Disclosed is an integrated tapping and drill attachment which includes a predetermined tapping configuration or mode which provides the desired flexibility for tapping, and also a predetermined drilling configuration or mode which provides the desired concentric and axial guidance as well as the desired rigidity for drilling operations.

Self-reversing tapping attachments have long been known in the tapping and machining industry for creating reliable tap holes in work pieces. Examples of such prior tapping attachments are illustrated in: U.S. Pat. No. 8,162,573, issued on Apr. 24, 2012, to Tapmatic Corporation; and U.S. Pat. No. 5,865,575, issued on Feb. 2, 1999, to Tapmatic Corporation; and which are each hereby incorporated in their entirety herein by this reference.
Self-reversing tapping attachments are used to create tap holes or apertures with internal screw threads. During the creation of a tap hole with self-reversing tapping attachments, the machine spindle goes through several stages, namely: driving the rotating tap into the tap hole, slowing the forward drive or feed rate and the rotation until the tap comes to a stop in the work piece, reversing the direction of the rotation and accelerating or increasing the reverse rate of rotation to match the desired tap pitch as the tap is retracted.
In a typical situation when a machinist is working to prepare internally threaded screw holes, the machinist will first drill holes through the workpiece using a traditional drill and drill chuck to hold the drill during the operation. The machinist, after drilling the required holes in the workpiece, will then physically or manually remove the drill chuck out of the machine spindle and then install a tapping attachment into the machine spindle and thereafter perform the tapping function, i.e. tap the holes (creating the internally threaded apertures or holes). During the tapping function, the tap is to follow the drilled hole.
For tapping holes, it is desirable to provide what is referred to as compression float or flexibility for the tap, which provides better and more preferable tap holes. For drilling holes on the other hand, it is generally undesirable to provide or even allow compression float because it is understood this allows the drill bit to undesirably move or walk on the workpiece before penetrating it to drill or cut the aperture or drill hole. It is also desirable to provide support so that concentricity is maintained during the operation(s).
One prior attempt to address some of the problems that some embodiments of this invention solve for example, was to provide a special cutting tools sometimes referred to as a "Drap" or combination drill-taps. These cutting tools can be used to drill and tap holes that go all the way through the material. The front of the cutting tool is a drill and the upper portion is a tap. After the drill portion of the cutting tool breaks through the work piece, the tap part can enter the hole to complete the threads.
In some of these prior attempts, others have attempted to use self-reversing tapping attachments with these Draps. However, it was learned that using a normal tapping attachment is undesirable. For example, when drillings it is important that the drill be guided concentrically and it is also best if it is held from moving axially. Normal tapping attachments allow the tap to float axially and the prior art tapping attachments may also typically include some radial play—which allows the drill to move off center when starting into the work piece. If additional pressure is imposed on the drill during the drilling operation, this pressure also tends to cause excess and/or premature wear on the bearings or other mechanisms used to provide the controlled axial movement.
It is an object of some embodiments of this invention to provide such a tapping attachment that strictly guides the drill concentrically and solidly so that the drill enters the workpiece without moving off center. Some embodiments of this invention utilize a taper configuration to guide the drill concentrically and solidly so that it enters the workpiece.
Up until now the industry has not found or provided a reasonable solution to the differing or competing preferred needs of drilling versus tapping.
It is also desirable in some applications of this invention to provide a tapping attachment which additionally provides a relatively quick and easy drilling function, and also that may be used on different types of manually operative machines with rotating spindles, along with automated applications.
Other objects, features, and advantages of this invention will appear from the specification, claims, and accompanying drawings which form a part hereof. In carrying out the objects of this invention, it is to be understood that its essential features are susceptible to change in design and structural arrangement, with only one practical and preferred embodiment being illustrated in the accompanying drawings, as required.


An insert for an external fixation has two jaws for clamping a rod-shaped element. The insert includes a locking element and is an angled piece having two free ends, with at least one engagement edge for engagement into the rod-shaped element being provided at its one free end. The insert has a recess or bore for engagement with a locking shaft of the clamp provided at the free end thereof that lies opposite to the free end having the rod engagement edge. The insert is angled so that it may extend through a passageway in one of the jaws and into a cavity formed in the jaw for receiving the rod. The insert rod engaging edges are tapered to bite into the rod to prevent its movement.

The invention relates to an insert for a clamping element for clamping a rod-shaped element of an articulated connection, particularly for a clamping element of an articulated connection for stabilizing bone fractures. Furthermore, the invention relates to an articulated connection having two clamping elements and having a locking element. In particular, the invention relates to an insert for optimizing the fixation of round rods in an external fixation system.
An articulated connection is known from U.S. Pat. Nos. 5,741,252, 5,752,954, 6,080,153, 6,342,054, 6,616,664, and 6,702,814, respectively, which consists of two or four individual clamping jaw elements and a central shaft or screw. In the case of this articulated connection, it is possible to introduce one or two rod-shaped elements into the corresponding cavities from the side. In U.S. Pat. No. 5,752,954, a spring is disposed between the two center clamping jaw elements, and it is possible to clip the rod-shaped elements in, counter to its spring force, and thereby hold the articulated connection in place against the rod-shaped elements, before it is locked in position. In U.S. Pat. No. 6,616,664, narrow lever arms disposed on the side are provided, in order to hold rod-shaped elements that have been inserted from the side in place before the articulated connection is locked in position.
These known articulated connections are particularly used with frame-type systems for external treatment of bone fractures, also referred to as external fixators. By means of a suitable material pairing of the clamps of the articulated connection and of the rods, for example steels of different hardness or a combination of steel and aluminum, or also by means of suitable surface structures of the interior surface of the clamp and the mantle surface of the rod, the result can be achieved that the rod-shaped elements are sufficiently secured against rotation and axial displacement after the locking screws have been fixed in place.
It is desirable to construct such external fixators using non-metallic materials, for example plastic materials, particularly in order to achieve a weight reduction of such a system. If the modules or parts of such a clamp are made of plastic injection-molded materials, there may be the difficulty in finding suitable material pairings with which sufficient fixation can be achieved. This is a problem particularly because many plastics are characterized by negative creep behavior, which causes connections that have been tightened to gradually come loose, i.e. to lose their gripping power.
Another problem that arises with such configurations is the high pressure stress on the plastic parts when the screw connection has been tightened, and this stress can result in stress cracks due to irregular stress on the plastic structure. This is particularly dangerous because such defects only occur after a certain period of time, and are not clearly evident optically.


Packaged integrated circuits having inductors and methods to form inductors in packaged integrated circuits are disclosed. An example method comprises forming a substrate having a first trace and a contact, attaching an integrated circuit to the substrate over the first trace, and electrically coupling the first trace to the contact via an electrical conductor that extends over the integrated circuit to form the inductor in the packaged integrated circuit.

To satisfy consumer desire for more portable electronic devices, semiconductor manufacturers desire to incorporate as many devices as possible at the integrated circuit level to reduce the amount of circuit board area needed. It is not often possible to incorporate certain devices such as high power resistors, large capacitors, or large inductors into an integrated circuit. Similarly, there is often not enough space within an integrated circuit package due to the large number of bond wires and traces that route signals to and from the integrated circuit.
Devices that cannot be incorporated into the integrated circuit and/or the integrated circuit package are attached to a circuit board, thereby consuming valuable circuit board area and increasing the total cost of manufacturing, for example, a portable electronic device incorporating the integrated circuit(s) and the circuit board.
To clarify multiple layers and regions, the thicknesses of the layers are enlarged in the drawings. Wherever possible, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. As used in this patent, stating that any part (e.g., a layer, film, area, or plate) is in any way positioned on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part, means that the referenced part is either in contact with the other part, or that the referenced part is over the other part with one or more intermediate part(s) located therebetween. Stating that any part is in contact with another part means that there is no intermediate part between the two parts.


Flexible epoxy-based adhesive compositions which remain Theologically stable at room temperature in an uncured state comprise: (a) at least one flexible polyepoxide resin having a hardness not exceeding a durometer Shore D reading of 45 when cured with a stoichiometric amount of diethylene triamine (xe2x80x9cDETAxe2x80x9d); and (b) a substantially stoichiometric amount of at least one latent epoxy resin curing agent. Optionally, the adhesive composition may also incorporate one or more semi-flexible resins. Other optional components include fillers, thixotropic agents, and flexibilizers. The adhesive composition provicdes an epoxy-based adhesive composition that is storable for weeks as a single component mixture at room temperature, curable at temperatures ranging from about 100xc2x0 C. to 125xc2x0 C. in less than two hours, and flexible upon curing to temperatures as low as minus 50xc2x0 C., exhibiting a durometer Shore A of less than about 95.

The present invention relates generally to compositions used as adhesives. More particularly, the present invention relates to flexible epoxy compositions for use as adhesives, which are designed to be stable at room temperature.
The flexible polymer market offers a wide variety of adhesive polymers, including such compounds as polyurethanes, polysulfides, silicones, and epoxy compounds. In particular, epoxy compounds demonstrate the ability to strongly adhere to a variety of materials, including metal, glass, plastic, wood, and fiber, and consequently are often used to bond dissimilar materials. However, various disadvantages long associated with epoxy compounds have dampened industry enthusiasm for using epoxy compounds as adhesives in automated bonding processes.
One-component epoxy-based adhesives are available for industrial application in two basic forms: rigid epoxy adhesives and frozen pre-mix, flexible epoxy adhesives. Rigid epoxy adhesives include such compounds as Bisphenol-A epoxy adhesives and novolacs. These rigid epoxy adhesives exhibit strong adhesion for many materials and may be conveniently stored at room temperature. However, these adhesives form brittle bonds that are often insufficiently pliant for bonding dissimilar materials. For example, a brittle bond between dissimilar materials with different thermal expansion rates may be unable to withstand the stresses caused by the thermal mismatch, so that both the bond and its adherends may be susceptible to failure.
Frozen pre-mix, flexible epoxy adhesives are also employed by industry, although the usage of such adhesives is far surpassed by the usage of rigid epoxy adhesives. A description of frozen pre-mix, flexible epoxy adhesives is found in U.S. Pat. No. 4,866,108, assigned to the present assignee, which discloses and claims the composition behind Flexipoxy 100 Adhesive, a frozen flexible epoxy adhesive developed for spacecraft electronic applications. In comparison to rigid epoxy adhesives, flexible epoxy adhesives form more pliable bonds that are capable of successfully adapting to stresses between dissimilar materials caused by differing rates of expansion. However, in contrast to rigid epoxy adhesives, frozen pre-mix flexible epoxy adhesives must be stored in a frozen state and must be thawed prior to use. Moreover, frozen adhesives offer a limited working life of only about 2 to 8 hours once thawed, whereas at least one week of working life is realistically required for general automated bonding operations. Therefore, frozen pre-mix, flexible epoxy adhesives are widely considered impractical for use in high volume automated processing given the scheduling difficulties wrought by both the need to thaw the adhesives as well as the limited working life available after thawing.
Thus, a need remains for a one-component epoxy adhesive that offers the convenience of room temperature storage while also providing pliable bonds capable of withstanding the rigors of varying expansion rates-between bonded materials. This need is particularly acute for high volume automated bonding operations, which can tolerate neither frequent periods of downtime for thawing nor the expense of discarding adhesives that quickly become ineffective. This need must be achieved without sacrificing good adhesion characteristics.
In accordance with the present invention, epoxy adhesive compositions are provided which are storable at room temperature, produce non-brittle, flexible bonds, exhibit strong adhesion, and have good processing characteristics. These compositions possess most, if not all, of the advantages of the above prior art compositions while overcoming their above-mentioned significant disadvantages.
The room-temperature stable, one-component, flexible epoxy-based adhesive compositions of the present invention comprise:
(a) at least one polyepoxide resin having a hardness not exceeding a durometer Shore D reading of 45 when cured with a stoichiometric amount of diethylene triamine (xe2x80x9cDETAxe2x80x9d); and
(b) a substantially stoichiometric amount of at least one latent epoxy resin curing agent,
wherein the cured combination of the polyepoxide resin and the latent curing agent exhibits a durometer Shore A of less than 95.
The polyepoxide resin component of the present compositions is a flexible epoxy resin. Flexible epoxy resins are defined herein to be those epoxy resins having a durometer Shore D measurement of 45 or less when cured with DETA. Polyepoxide resins suitably employed in the practice of the invention include, but are not limited to, diepoxide resins, triepoxide resins, and poly(oxypropylene)epoxide resins. Optionally, the epoxy resin component may also incorporate a semi-flexible resin such as the adduct of two moles of bisphenol A with one mole of the diglycidyl ester of linoleic dimer acid, the trifunctional novolac epoxy of cardanol, and the difunctional epoxy of cardanol. Semi-flexible epoxy resins are defined to be those epoxy resins having a durometer Shore-D value ranging from about 45 to 75 when cured with DETA. In comparison, rigid epoxy resins are defined as epoxy resins having a Shore-D value exceeding about 75 when cured with DETA.
The epoxy resin curing agent employed to cure the epoxy resin is a latent curative. As such, there is no reaction between the curing agent and the epoxy resin component at room temperature. Rather, the epoxy resin component is cured in the presence of the curing agent upon exposure to elevated temperatures. The present combination of epoxy resin and the latent epoxy resin curing agent remains uncured and Theologically stable at room temperature for months or even years, thus providing a long storage life conducive to automated bonding operations.
Aside from epoxy resin and latent curing agent components, other components that may be optionally added to the present adhesive compositions include fillers, thixotropic agents, and flexibilizers.
The present adhesive compositions are prepared by first mixing the following components to form a thoroughly wetted mass: (1) liquid components comprising the flexible polyepoxide component, and optionally, at least one component selected from the group consisting of flexibilizers and semi-flexible resins; and (2) solid components comprising at least one latent epoxy resin curing agent, and optionally, at least one component selected from the group consisting of fillers and thixotropic agents. The thoroughly wetted mass is then reacted at a temperature ranging from about 100xc2x0 C. to 175xc2x0 C. to form the present cured flexible epoxy adhesives, although the composition is designed to cure at a relatively low temperature ranging from about 100xc2x0 C. to 125xc2x0 C. in less than about two hours.
In sum, the adhesive of the present invention is novel in providing an epoxy-based adhesive composition that is storable for weeks as a single component mixture at room temperature, curable at relatively low temperatures in less than two hours, and flexible upon curing to temperatures as low as xe2x88x9250xc2x0 C. Thus, the present adhesives offer the best features of the prior art adhesives. Like the frozen, pre-mix, flexible epoxy adhesives, the present adhesives form pliant bonds that withstand the stresses of thermal mismatch. Like the rigid epoxy adhesives, the present compositions may be conveniently stored at room temperature and easily processed. The ability of the present adhesives to provide strong flexible bonds without wreaking havoc on production schedules effectively promotes epoxy-based adhesives to use in automated bonding processes. In short, these adhesives enable industry to avail itself of the excellent adhesive qualities associated with epoxy compounds without sacrificing the advantages of automation. Importantly, the compositions of the present invention offer these benefits without employing solvent components, so that environmental integrity is maintained.
The adhesive compositions of the present invention have been developed to provide industry with the ability to store epoxy-based adhesives at room temperature, as well as to provide good adhesion qualities, flexibility, and ease of processing.
The compositions of the present invention are based on the use of a combination of selected epoxy resins and a curing agent which will provide a flexible product that is storable at room temperature in an uncured state. The selection of the particular epoxy resins and the curing agent is critical in obtaining the desired flexibility in the final adhesive product.
The compositions of the present invention employ at least one polyepoxide resin falling within the class of so-called xe2x80x9cflexible epoxy resinsxe2x80x9d. The phrase xe2x80x9cflexible epoxy resinxe2x80x9d is intended to encompass epoxy resins having a durometer Shore D reading not exceeding 45 when cured with diethylene triamine (xe2x80x9cDETAxe2x80x9d). Flexible polyepoxide resins suitably employed in the practice of the invention include, but are not limited to, diepoxide resins, triepoxide resins, and poly(oxypropylene)epoxide resins. The internal flexibility exhibited by flexible polyepoxide resins derives from such features as long aliphatic chains, ether and ester linkages in the polymer chains, and double carbon-carbon bonds, which increase flexibility by enhancing the rotation of adjacent single carbon-carbon bonds.
Examples of polyepoxide resins suitably employed in the practice of the invention include such diepoxide resins as the following three compounds that are commercially available from Shell Chemical Co. of Houston, Tex.: (1) the diglycidyl ether of 1,4-butanediol, which has an epoxy equivalent weight of about 130 and is sold under the trade designation Heloxy 67, (2) the diglycidyl ether of neopentyl glycol, which has an epoxy equivalent weight of about 135 and is available under the trade designation Heloxy 68, and (3) the diglycidyl ether of cyclohexane dimethanol, which has an epoxy equivalent weight of about 160 and is sold under the trade designation Heloxy 107. Examples of poly(oxypropylene)epoxide resins suitably employed in the practice of the invention include the diglycidyl ether of polyoxypropylene glycol, which is commercially available from Dow Chemical, Midland, Mich., under the trade designations DER 732 and DER 736, having epoxy equivalent weights of about 320 and 190, respectively. Another suitable poly(oxypropylene)epoxide is the diepoxide of a polyoxypropylene diol, which has an epoxy equivalent weight ranging from about 290 to 325 and is commercially available from Shell Chemical Co. under the trade designation Heloxy 502. An example of suitably employed polyepoxide resin that is classified as both a poly(oxypropylene)epoxide resin and a triepoxide resin is 10 the polyglycidyl ether of an aliphatic polyol, which has an epoxy equivalent weight of about 650 and is commercially available from Shell Chemical Co. under the trade designation Heloxy 84.
It is important to note that not all so-called flexible polyepoxide resins are suitable for the practice of the invention. For instance, certain flexible epoxy resins fail to cure in a reasonable amount of time with available latent epoxy resin curatives. One example is the polyglycidyl ether of castor oil, which has an epoxy equivalent weight of about 600 and is commercially available from Shell Chemical Co. of Houston, Tex., under the trade designation Heloxy 505.
The compositions of the present invention may optionally employ so-called xe2x80x9csemiflexible epoxy resinsxe2x80x9d as secondary resins. The phrase xe2x80x9csemi-flexible epoxy resinxe2x80x9d is intended to encompass epoxy resins having a durometer Shore D reading ranging from about 45 to 75 when cured with DETA. While semi-flexible resins are too rigid to serve as primary resins in the practice of the invention, these resins may be used to enhance certain properties of the adhesive composition, such as lap shear strength. While these secondary resins are useful as modifiers, they lack the flexibility or elongation necessary to serve as primary resins. More specifically, the addition of a semi-flexible epoxy resin to the present adhesive composition increases the composition""s glass transition temperature Tg, which represents the temperature at the mid-point in the transition from glassy to rubbery behavior by a polymer. Since it is important that the present adhesive compositions have a glass transition temperature Tg well below temperatures to which the present adhesive compositions may be exposed during their service life (including sub-zero conditions found outdoors), the concentration of semi-flexible resins in the present compositions must be limited. The maximum allowable concentration of semi-flexible resin will vary according to the composition of the adhesive as well as the lowest expected service temperature for the adhesive. However, as a general rule, the amount of semi-flexible epoxy resin present in the adhesive composition preferably does not exceed 40 wt % of the epoxy resin component.
Examples of semi-flexible resins suitably employed in the practice of the invention include the following compounds: (1) the adduct of two moles of bis-phenol A with one mole of linoleic dimer acid, which has an epoxy equivalent weight of about 700 and is commercially available from the Shell Chemical Company, Houston, Tex., under the trade designation EPON 872; (2) the trifunctional novolac epoxy of cardanol having an epoxy equivalent weight of about 600, as available from the Cardolite Corp., Newark, N.J., under the trade designation NC-547; and (3) the difunctional epoxy of cardonal having an epoxy equivalent weight of about 350, as available from Cardolite Corp. under the trade designation NC-514.
The curing agents used in the present compositions are chosen to provide a flexible product from the selected epoxy resins. The present curing agents are characterized by long aliphatic moieties in their structure which allow compatibility with the selected resins at cure temperature. The present curing agents are further characterized as xe2x80x9clatentxe2x80x9d curatives. A latent curative is one that does not operate to cure an epoxy resin until melted in the elevated temperatures of a curing process while in contact with the targeted epoxy resin.
Examples of curing agents that may be suitably employed in the practice of the invention to achieve flexible epoxy adhesives (in view of the selected classes of epoxy resins, the selected cure temperature range of about 100xc2x0 C. to 125xc2x0 C., and the selected cure time of less than two hours) include dihydrazide curing agents, although the choice of curing agent is not so limited. Examples of dihydrazide curing agents suitably employed in the practice of the invention include the following compounds available from Ajinomoto Co., Inc., of Teaneck, N.J.:
(1) aliphatic dihydrazide with Diuron accelerator (3-(3,4-dichlorophenyl)-1,1-dimethyl urea), having an active hydrogen equivalent weight of 134 as available under the trade designations Ajicure AH-122 and Ajicure AH-123;
(2) adipic acid dihydrazide with Diuron accelerator (3-(3,4-dichlorophenyl)-1,1-dimethyl urea), having an active hydrogen equivalent weight of 49 as available under the trade designation Ajicure AH-127;
(3) icosanedioic acid dihydrizide (C20H42N4O2), having an active hydrogen equivalent weight of 92.5 as available under the trade designation LDH, with about 10% of the compound as sold being hexadecanedioic acid dihydrazide according to the Ajinomoto material safety data sheet (xe2x80x9cMSDSxe2x80x9d);
(4) 7,11-octadecadiene-1,18-dicarboxylic acid dihydrazide (C20H38N4O2), having an active hydrogen equivalent weight of 91.5 as available under the trade designation UDH; and
(5) Valine dihydrazide, having an active hydrogen equivalent weight of 78.5 as available under the trade designation of VDH.
Preferably, AH-122, AH-123, and AH-127 are employed in the practice of the present invention.
Certain curing agents are known to fail in meeting one or more of the objectives of the present invention. For example, the polyarine adduct of epoxy resin, commercially available from Air Products, Allentown, Pa., under the trade designation Ancanine 2014, displays poor compatibility with flexible epoxy resins and results in unacceptably long cure times. Likewise, epoxy-amnine adducts, such as commercially available from Ajinomoto Co., Inc. under the trade designations Ajicure PN-23 and Ajicure MY-24, prove incompatible with flexible epoxy resins.
The amount of latent curing agent is preferably in stoichiometric proportion relative to the epoxy resin employed. In general, the amount of curing agent may be varied about xc2x115 percent from stoichiometry, with little adverse effect on the final product. The severity of adverse affects deriving from employing more or less than the exact stoichiometric amount of curing agent depends upon the fuinctionality of the ingredients employed (e.g., trifunctional epoxy resins fare better than difunctional epoxy resins) and the cure temperatures employed (e.g., resins cured at higher temperatures fare better than those cured at lower temperatures).
One novel feature of the invention is that the uncured combination of epoxy resins and a latent curing agent is stable at room temperature. More specifically, the uncured combination is rheologically stable at room temperature so that it does not cure at room temperature and is stable in terms of viscosity. Thus, unlike frozen, pre-mix flexible epoxy compounds, the present compositions may be cured relatively quickly (less than two hours) on an as-needed basis. Upon cure, the present compositions remain flexible and reworkable, with a Durometer Shore A of less than 95. Another novel feature of the present composition is that its flexibility extends to as low as minus 50xc2x0 C. (xe2x88x9250xc2x0 C.), as measured by glass transition temperature Tg. This compares to typical glass transition temperatures in excess of +100xc2x0 C. for rigid epoxy adhesives.
Optionally, the composition of the present invention may include reactive or nonreactive flexibilizers, preferably not exceeding 50 wt % of the total liquids in the adhesive, which include the epoxy resins and the flexibilizers. Both reactive and non-reactive flexibilizers serve to enhance the flexibility and reworkability of the final adhesive composition, albeit by different mechanisms. Reactive flexibilizers act as internal plasticizers, typically taking the form of long aliphatic chains which are pendant to the main polymer network. Reactive flexibilizers include rubbery polymers which have a suitable reactive group. Examples of such flexibilizers include polysulfides (such as Thiokol LP3, which is a liquid polysulfide reactant available from Morton Chemical of Chicago, Ill.), polyamides, and carboxyl-terminated butadiene rubbers.
On the other hand, non-reactive flexibilizers act as external plasticizers which do not chemically attach to the polymer network but are retained in the network due to van der Waals attraction and/or hydrogen bonding. Consequently, they must have a chemical structure compatible with the epoxy/curative structure in order not to be expelled. Plasticizers with high molecular weight are desirable, since the increased chain entanglement between plasticizer and the epoxy/curative structure serves to decrease migration of the plasticizer. Simple experimentation to determine compatible plasticizers, such as by preparing a polymer and proposed plasticizer and observing whether compatibility exists, may be done. Such experimentation is considered to be a routine endeavor that is well within the capabilities of those having ordinary skill in the art and is not considered to be undue.
Polyols having molecular weights of at least 1,000 and triols with molecular weights ranging from 1,500 to 6,000 are commonly employed as non-reactive plasticizers. Examples of high molecular weight triols suitably employed in the practice of the invention are high molecular weight poly(oxypropylene)triol (available from Union Carbide, Danbury, Conn., under the trade designation LHT-28) and hydroxyl-termiinated polybutadiene (available from Atochem, under the trade designation Poly BD R45HT). Other examples of suitable non-reactive flexibilizers include phthalate esters, adipate esters, and methyl lineolate.
The adhesive composition may also optionally include a thixotropic agent. Thixotropic agents are used to prevent settling of the curative, which is in powder form and is prone to separating from the liquid epoxy resin during cure. More specifically, thixotropic agents retard settling of the curative by increasing the low shear viscosity of the liquid. The thixotropic agent may comprise any of the well-known materials for this purpose, such as fine particle fillers like clays, talc and, preferably, fumed silica. The amount of thixotropic agent is that amount which is effective in producing the desired thixotropic properties of the final product, i.e., that amount which prevents the paste or film from flowing under its own weight. Simple experimentation will readily determine the appropriate amount of thixotropic agent in the adhesive composition. The scope of experimentation required to determine the proper concentration of thixotropic agent is considered to be reasonable for those having ordinary skill in the art and is not considered to be undue. As a general rule, it is preferred in the practice of the invention that the thixotropic agent be limited to 5 wt % of the total liquids in the adhesive composition, with a concentration ranging from about 1 to 5 wt % of the total liquids being more preferred. It is noted that the components making up the total liquids in the adhesive composition include the epoxy resins and any flexibilizers. The preferred particle size for a thixotropic agent in the practice of the invention ranges from about 0.01 to 0.1 xcexcm.
Other optional additives to the flexible epoxy adhesive composition include fillers, UV stabilizers, antioxidants, and processing aids. If employed, the amount of filler should be adjusted to impart a smooth paste-like consistency to the liquid adhesive, keeping in mind that the filler preferably does not exceed 60% by volume of the total liquids in the adhesive, which include the epoxy resins and any flexibilizers. More preferably, the filler does not exceed 50% by volume of the total liquids in the adhesive. Further, the particle size of the filler material should be considered in formulating the adhesive composition, since the filler and curative particulate materials likely compete for space within the adhesive cornposition. This potential overcrowding problem can be overcome by selecting different particle sizes for curative and filler such that the smaller particle fits into the interstices between the larger particles. At any rate, the adhesive composition is best served if the filler material is fine and measures less than 44 xcexcm in diameter, which correlates to the standard 325-mesh sieve size.
Processing aids that may be employed in the practice of the invention include wetting agents, anti-foaming agents, and dispersing agents, all of which are known and commonly used in the art. The processing aids are preferably employed at a concentration of up. to 5 wt % of the total adhesive composition.
The adhesive of the present invention is formulated by mixing the liquid components (namely, the epoxy resins and flexibilizers) with the dry ingredients (namely, the curing agents, thixotropic agents, and fillers) in their appropriate concentrations until the dry ingredients are thoroughly wetted. Preferably, the dry ingredients are milled into the liquid ingredients, for example, using a 3-roll mill. Milling achieves a good blend of resin and curative so that the resulting adhesive is uniform in composition and therefore exhibits higher overall quality. Once the dry ingredients are thoroughly wetted, air is removed from the adhesive mixture by further mixing it under vacuum. The resulting uncured composition may be stored at room temperature for several weeks. Further, storage for extended periods of time may be done at temperatures not exceeding 35xc2x0 C.
When the mixture comprising the present composition is to be used as an adhesive, the mixture must be cured. First, the mixture is placed in contact with the materials to be bonded in the manner desired for adhesion. Then, the mixture is cured by heating both the materials to be bonded and the inserted mixture to an elevated cure temperature. While a cure temperature as high as 175xc2x0 C. may be employed depending upon the particular electronics application, the present adhesive compositions are designed to cure in less than about 2 hours at a temperature ranging from about 100xc2x0 C. to 125xc2x0 C. The minimum curing temperature varies by formulation, but below 70xc2x0 C., the mixture will not properly cure. While cure times vary with the melting point and molecular weight of the curing agent, the cure time for the adhesives of the present invention does not exceed about 2 hours. It is contemplated that in most cases the cure time need only be approximately 30 minutes. Upon cure, the present adhesive composition forms a strong, flexible bond between the materials that remains flexible down to a glass transition temperature Tg as low as xe2x88x9250xc2x0 C., with the precise minimum Tg depending on the formulation of the adhesive.

Adhesive of flexible epoxy resin and latent dihydrazide


A friction stir welding spindle includes a support having a center bore. A spindle shaft is adapted to support a stir welding tool and extends within the bore. A bearing assembly allows simultaneous rotational and axial displacement of spindle shaft in the bore relative to the support. A sensing device is adapted to provide an output signal indicative of at least one of a force coincident with axial displacement of the spindle shaft and an axial position of the spindle shaft.

The present invention relates to a friction stir welding machine. More particularly, the present invention relates to a spindle for a friction stir welding machine.
Friction stir welding is a process of welding component parts together using friction heat generated at a welding joint to form a plasticized region that solidifies to join workpiece sections. Welding is performed by inserting a probe into a joint between the workpiece sections. The probe includes a pin that is inserted into the joint and a shoulder, which is urged against the surfaces of the workpieces. The pin and shoulder spin together to generate friction heat to form the plasticized region along the joint for welding operation.
Various parameters must be controlled in order to form a quality weld. One of the more critical parameters is the depth of the probe. As is known in the art, the depth of the probe can be controlled using either position or load control. Position control is generally difficult because of the high loads present on the spindle during the welding process. In particular, the spindle and the probe are under a considerable load, which will cause flexure and bending in various components thereof, which in turn will affect the accuracy of the position measurement. In view that the spindle must also operate in multiple degrees of freedom, the individual loading on the components of the spindle can vary depending on the position of the spindle in space. In addition, thermal expansion of the probe must also be taken into account in position control.
Load control has also been used to control the welding process. Load control requires measuring the normal load or force on the welding probe (i.e. the force coincident with the spinning axis of the probe). Prior art techniques for load control require supporting the whole spindle assembly on one or more load cells. Since the spindle assembly is commonly quite heavy, the load cells used must be of large capacity, which increases the cost of the machine and as well as generally sacrificing accuracy.
One aspect of the present invention is a friction stir welding spindle that includes a support having a center bore. A spindle shaft is adapted to support a stir welding tool and extends within the bore. A bearing assembly allows simultaneous rotational and axial displacement of spindle shaft in the bore relative to the support. A sensing device is adapted to provide an output signal indicative of at least one of a force coincident with axial displacement of the spindle shaft and the axial position of the spindle shaft.
In another aspect of the present invention, a portion of the spindle shaft cooperates with the support, forming an actuator adapted to cause axial displacement of the spindle shaft relative to the support. For instance, the actuator can be fluidly operated from pressurized fluid wherein the portion of the spindle shaft cooperates with the inner surface of the bore to form pressurizable chambers which, when pressurized, will cause axial displacement of the spindle shaft relative to the support. Pneumatic or hydraulic operation can be employed. In yet other embodiments, the spindle shaft and the support can cooperate magnetically to form an actuator.

Friction stir welding spindle with axially displaceable spindle shaft


A marine sanitation holding vessel basically comprising a welded aluminum barge; a waste removal system mounted on the barge; and a ventilation system mounted on the barge. The barge is of modular construction and comprises three basic sections: first and second end sections and an elongate middle section. The waste removal system includes first and second pumps, a battery for storing power for operating the pumps, a receptacle for receiving waste from portable toilets, and a solar generating system for charging the battery. The first pump withdraws waste material from the holding tank to be emptied and deposits it into the barge storage tank. The second pump provides water for cleansing the receptacle for receiving waste collected in portable toilets. The ventilation system comprises a hollow mast painted black to heat the mast and thus generate an upward draft within the mast which draws the fumes from within the storage tank. The ventilation system further comprises a charcoal filter element located below the mast through which the fumes must pass while being ventilated to the surrounding environment. The mast is hinged to the barge to allow the mast to be rotated towards the horizontal to allow access to: (a) the charcoal filter element and an opening into the barge storage tank; and (b) the interior of the storage tank.

Passengers on pleasure boats are faced with the problem of collecting and disposing of waste material including excreta and other human waste generated during the voyage. The large numbers of pleasure boats on the water today render it unsanitary to dump this waste material directly into the water; this is especially true with such relatively confined bodies of waters as lakes and coastal waterways and near marinas and other areas where large numbers of boats congregate. Accordingly, many pleasure craft are provided with self-contained bathroom facilities or portable toilets in which this waste material may be collected.
Because the holding tanks on such pleasure craft contain relatively small amounts of this waste, they must frequently be emptied. Land-based collection stations located near marinas are predominantly used to remove this waste from pleasure craft holding tanks because of the easy availability of sewer lines and power to operate pumps. However, the dock space at such marinas is limited, preventing the dedication of dock space for a waste collection stations. The dock space provided for such a collection station may also not be easily accessible. Additionally, such land-based collection sites are inappropriate in remote areas where such craft may congregate because sewer lines and power for pumping stations are not found in such remote areas; further, these remote areas may not be provided with permanent docks which can be piped to accommodate such a land-based collection station.
In at least one instance, a floating waste collection station has been provided in a lake. This collection station comprised a converted barge provided with a solar powered electric pump for pumping waste from the pleasure craft holding tank into the hold of the barge. A pleasure craft is tied up to the barge, and the operator of the pleasure craft operates the pump as necessary to empty the holding tank of his craft. While this barge was nominally effective, it suffered many problems related to the design and construction of the barge and waste removal system provided thereon.

American Eagle Aluminum Manufacturing, Inc.


A catalytic Wittig method utilizing a phosphine including the steps of providing a phosphine oxide precatalyst and reducing the phosphine oxide precatalyst to produce the phosphine; forming a phosphonium ylide precursor from the phosphine and a reactant; generating a phosphonium ylide from the phosphonium ylide precursor; reacting the phosphonium ylide precursor with the aldehyde, ketone, or ester to form the olefin and the phosphine oxide which then reenters the cycle. The invention is also directed to a Mitsunobu reaction catalytic in phosphine.

The formation of carbon-carbon double bonds represents one of the pillars on which modern synthetic chemistry is based because the production of many natural products and drugs necessitate their assembly. Consequently numerous processes for the construction of carbon-carbon double bonds have been developed. Besides direct elimination, there are currently four reliable methodologies for the routine formation of alkenes: the Wittig, Peterson, and Kocienski-Julia olefination reactions, as well as metathesis. Currently only metathesis is catalytic and even this is limited in requiring alkene starting materials, with high loading of a suitably ligated transition metal catalyst, usually Ru or Mo, often required and, in the case of ring closing metathesis, high dilution. The use of transition metals may lead to complications in that any transition metal must be removed or substantially reduced for any products intended to be used as active pharmaceutical agents, for example.
In addition, environmental concerns increasingly influence decision making insofar as chemical synthetic route selection, which is impacted by the waste and energy consumption profile of a particular process. The Wittig reaction, for example, which is the most widely employed olefination process, comes at a cost—the stoichiometric formation of phosphine oxide byproduct.
Therefore the development of new eco-friendly catalytic methodology, which either limits the generation of waste or downgrades the waste produced, for example from toxic to harmful, would be highly desirable. The successful design and implementation of organocatalytic processes offers the possibility of lessening the environmental footprint that chemical industries have on their surrounding ecology. Therefore, an organocatalytic methodology that yields the possibility to construct olefins selectively would represent an important advance.
Of the three stoichiometric olefination processes mentioned above, the only one that may offer the realistic possibility to transition from a stoichiometric to a catalytic process, coupled with the selective formation of either E or Z alkenes, is the Wittig reaction. The Wittig reaction was discovered in 1953 by Georg Wittig and involves the treatment of an aldehyde or ketone with a phosphonium ylide, which yields an alkene concomitant with the generation of a phosphine oxide. Wittig's pioneering studies in this area resulted in his receipt of the 1979 Noble Prize for Chemistry. Since its discovery, the Wittig reaction has been used extensively, demonstrated by its inclusion in numerous natural product syntheses and undergraduate laboratory courses and teaching texts.
FIG. 1 illustrates a prior art textbook illustration for the Wittig reaction. The accepted mechanism involves the attack of a phosphonium ylide on an aldehyde or ketone, yielding an oxaphosphetane intermediate. Formation of the oxaphosphetane can occur through a direct [2+2] cyclo-addition reaction between the phosphonium ylide and the carbonyl compound. Alternatively it has been proposed that a betaine intermediate is first formed. The oxaphosphetane intermediate subsequently collapses via a retro-[2+2] cyclo-addition reaction to produce the desired alkene concomitant with phosphine oxide byproduct. Further discussion of the Wittig reaction can be found in O'Brien et al., Angew. Chem. Int. Ed. 2009, 48, 6836-6839 and references cited therein.
Although there has been significant work directed towards the development of the Wittig reaction, significant problems still persist and remain to be addressed. For one thing, the process is stoichiometric and for another, complete removal of the phosphine oxide byproduct is at best time consuming or is impossible. In some cases also, Wittig reactions give diastereomeric mixtures with ensuing purification issues. A catalytic protocol would reduce the amount of the phosphine oxide byproduct. The lack of a catalytic protocol also removes from serious consideration the possibility to control the olefination by alteration of the phosphine's structure. This is unfortunate, as the phosphine's structure has been shown to have a substantial impact on the stereochemical outcome of the reaction, and therefore a carefully designed phosphine may yield a selective process.
That said, the barriers to the development of a catalytic Wittig reaction are formidable, and the successful construction of a catalytic process relies on the completion of four steps: A) formation of the phosphonium ylide precursor, typically a phosphonium salt; B) generation of the phosphonium ylide, normally by deprotonation; C) olefination with concomitant generation of phosphine oxide; and D) reduction of the phosphine oxide byproduct producing phosphine to reenter the catalytic cycle. The most daunting of the aforementioned processes is step D—the required chemoselective reduction of the phosphine oxide byproduct to a phosphine in the presence of either an aldehyde or ketone starting material and alkene product.
One could ameliorate this problem of chemoselective reduction by the replacement of phosphorus with arsenic, tellurium, or antimony, as their corresponding oxides, owing to bond strength, are appreciably easier to reduce. In fact, such an approach has led to the successful development of catalytic Wittig-type processes employing arsines and tellurides (For a review on catalytic aldehyde olefinations see F. E. Kuhn, A. M. Santos, Mini-Rev. Org. Chem. 2004, 1, 55-64). Unfortunately, significant drawbacks to the broad adoption of the aforementioned methodologies are the intrinsic high toxicity and carcinogenicity of arsenic, tellurium, and antimony compounds; environmental contamination particularly of groundwater would be one concern if these reactions were performed on a large scale. Importantly, the catalytic use of phosphine would not suffer from these issues; therefore a Wittig reaction catalytic in phosphine would find wider employment. Furthermore, this would marry the power of the Wittig olefination protocol to the synthetic benefits of a catalytic reaction without the poisoning issues that can plague transition metal catalyzed processes.
This aforementioned reduction of phosphine oxide to phosphine is pivotal to the successful development of any catalytic Wittig process; therefore the available methodology to effect this reduction merits a detailed discussion. To date the most successful class of reagents for the reduction of phosphine oxides to phosphines is silanes. Other methodologies exist but none have the scope and reliability of silanes. Fritzsche and co-workers first reported the reduction of phosphine oxides with silanes in 1964 (Fritzsche, H. et al., Reduction of organic compounds of pentavalent phosphorus to phosphines. I. Reduction of tertiary phosphine oxides to tertiary phosphines with silanes. Chem. Ber. 1964, 97, 1988-1993; Fritzsche, H. et al., Reduction of organic compounds with pentavalent phosphorus to phosphines. Reduction of tertiary phosphine oxides to tertiary phosphines with trichlorosilane. Chem. Ber. 1965, 98, 171-174; Fritzsche, H. et al., Reduction of organic compounds of pentavalent phosphorus to phosphines. III. Preparation of primary and secondary phosphines with silanes. Chem. Ber. 1965, 98, 1681-1687).
These publications are a thorough evaluation of silane reducing agents, and four successful reducing agents emerged: phenylsilane, diphenylsilane, triphenylsilane, and trichlorosilane. Since Fritzsche's work, phenylsilane and trichlorosilane have emerged as the most widely utilized with the latter, often coupled with an amine base, the most employed.
The mechanism of reduction is dependent on the silane, and in the case of trichlorosilane in the presence of an amine often leads to inversion of the phosphorus center, while with phenylsilane reduction is achieved with retention.
Efforts towards the development of catalytic processes in the Wittig reaction have primarily focused on two main areas: 1) catalytic generation of the phosphonium ylide or 2) substitution of phosphorous by arsenic due to the reduction of the arsenic-oxygen bond being more easily achieved than the analogous phosphorus-oxygen bond. However, neither represents a true catalytic Wittig reaction, as this would necessitate the catalytic use of phosphine. Indeed, the only documented use of catalytic phosphine was disclosed for the related aza-Wittig reaction; however, the reduction protocol, an isocyanate, cannot be utilized in the parent reaction. Therefore, the development of a catalytic Wittig reaction where the phosphine is the catalytic species has not before been achieved.
The Mitsunobu reaction also utilizes a phosphine, in the conversion of primary and secondary alcohols to esters, phenyl ethers, thioethers, and various other compounds. The general mechanism is shown in FIG. 7. Discovered in 1967 by Professor Oyo Mitsunobu, the reaction is extensively employed in academic and industrial laboratories due to its scope, stereospecificity, and mild reaction conditions. The Mitsunobu reaction, like the Wittig, employs a phosphine and produces a phosphine oxide as a byproduct. Like the Wittig reaction, the Mitsunobu reaction often suffers from problems related to product isolation and purification. These issues occur due to the formation of phosphine oxide and hydrazine byproducts.
There are three possible ways the Mitsunobu reaction can be made catalytic: in phosphine, in hydrazine, and in both. FIG. 8 illustrates a Mitsunobu reaction cycle catalytic in phosphine. The most challenging protocol to develop would be the duel catalytic protocol, which would necessitate a reducing agent (phosphine oxide to phosphine) and an oxidizing agent (hydrazine to azo compound) being present in the same flask.

Catalytic Wittig and Mitsunobu reactions

Board of Regents, The University of Texas System


Provided is a thin printed circuit board (PCB) for manufacturing a chip scale package (CSP). The thin printed circuit board includes a plurality of unit printed circuit boards, each of which is comprised of a circuit pattern, to which a semiconductor chip is adhered, and a substrate surrounding the circuit pattern. The unit printed boards are arranged in a row and includes a support molding, which is spaced a predetermined interval apart from the circuit pattern of each unit printed circuit board on the substrate of each unit printed circuit board and formed in a ring shape along the edge of the thin printed circuit board.

1. Field of the Invention
The present invention relates to a printed circuit board (PCB) for manufacturing a semiconductor package, and more particularly, to a thin PCB for manufacturing a chip scale package (CSP).
2. Description of the Related Art
In recent years, as most electronic products including various portable data communication devices, such as personal computers, cellular phones, and personal data terminals, have been scaled down and become more light-weight and efficient, their data processing capacities have increased. Thus, using a chip scale package (CSP) technique, a semiconductor chip can be assembled in a semiconductor package having a size similar to or slightly larger than the chip size. CSP techniques vary according to manufacturing methods, for example, a thin PCB method of manufacturing a CSP. In this method, semiconductor packages comprise a semiconductor chip manufactured with a thin PCB. However, the thickness (e.g., 0.17 mm or less) of a conventional thin PCB for manufacturing a CSP is typically smaller than that (e.g., 3 mm) of a conventional PCB for manufacturing a typical semiconductor package.
FIGS. 1 through 3 are diagrams illustrating problems of a conventional thin PCB. As shown in FIG. 1, in a conventional thin PCB 10, a plurality of unit PCBs 10a, 10b, and 10c are connected in a row. Although only three exemplary unit PCBs 10a, 10b, and 10c are illustrated in FIG. 1, the thin PCB 10 can include a greater number of unit PCBs. Circuit patterns 11a, 11b, and 11c are disposed in the unit PCBs 10a, 10b, and 10c, respectively. A plurality of holes (not shown) are formed in each of the circuit patterns 11a, 11b, and 11c. A plurality of holes or slots 12 are vertically arranged at interfaces between adjacent unit PCBs, for example, between the unit PCBs 10a and 10b or 10b and 10c. These holes or slots 12 suppress distortion of the PCB 10. A plurality of holes 13 are formed in an upper portion of the thin PCB 10, and a plurality of holes 14 are formed in a lower portion thereof. These holes 13 and 14 are used as recognition marks for a package manufacturing apparatus and may be used for alignment of the thin PCB 10 when the thin PCB 10 is transferred.
As described above, the thin PCB 10 has a relatively small thickness. Thus, the thin PCB 10 is flexible and makes it difficult to manufacture semiconductor packages. Thus, one solution shown in FIG. 2 was proposed. That is, semiconductor packages are manufactured using a carrier 20 supporting a thin PCB 10. In this method, since the thin PCB 10 is supported by the carrier 20, it is inflexible during package manufacturing processes. The carrier 20 can be formed of an inflexible material, for example, a sus material. A vacant space 23 is located in the center of the carrier 20 so as to expose the rear surface of the thin PCB 10. The carrier 20 is a kind of frame that surrounds the vacant space 23. Holes 21 are formed on both lateral surfaces of the carrier 20, and a mark 22 is formed on an edge thereof. The holes 21 and the mark 22 are used as recognition marks and may be used for alignment of the carrier 20 when the carrier 20 is transferred.
As shown in FIG. 3, in order to adhere the thin PCB 10 to the carrier 20, the thin PCB 10 is first mounted on the carrier 20. Only the upper and lower portions of the thin PCB 10 overlap upper and lower portions of the carrier 20 and are supported by the carrier 20, and the remaining portion of the thin PCB 10 do not overlap the carrier 20. Next, the thin PCB 10 is secured to the carrier 20 by an adhesive 31. The adhesive 31 is applied to the upper and lower portions of the thin PCB 10 and the upper and lower portions of the carrier 20.
As described above, since the conventional thin PCB 10 has a very small thickness, it should be adhered to a supporting portion such as the carrier 10 and used in package manufacturing processes. Thus, prior to the package manufacturing processes, additional processes of aligning and adhering the thin PCB 10 to the carrier 20 should be performed. Also, after a semiconductor package is completed, a process of removing the adhesive 31 from the carrier 20 should be further performed to reuse the carrier 20.

This patent is subject to a terminal disclaimer.

Thin printed circuit board for manufacturing chip scale package


A binder resin for sliding resistors contains an acetylene-terminated polyamic acid oligomer represented by the following general formula (I):

1. Field of the Invention
The present invention relates to binder resins for sliding resistors included in potentiometers for use in, for example, on-vehicle sensors, and also relates to sliding resistors formed using the binder resins. In particular, the present invention relates to a binder resin that can provide a sliding resistor capable of withstanding 50 million, or more than 100 million, sliding movements, and a sliding resistor formed using the binder resin.
2. Description of the Related Art
A potentiometer is generally used as a variable resistor in, for example, on-vehicle sensors. This device includes a resistor that is typically formed with a binder resin in which conductive particles, such as carbon black, are dispersed, and a slider, such as a metal contact brush, that can be moved over the resistor to change its resistance.
The binder resin used is generally a thermosetting resin such as phenol resin and epoxy resin. Examples of the conductive particles used include carbon black and carbon fiber, which also serves to increase the durability to sliding movements. The resistor is formed by mixing and dispersing the conductive particles into the binder resin together with a solvent to prepare a resistor paste, applying the resistor paste directly onto an insulating substrate by, for example, screen printing, and firing the resistor paste.
For example, sliding components such as on-vehicle sensors installed in the vicinity of engines are exposed to increased temperatures of about 100° C. to 120° C. Sliding components used in such a hostile environment therefore need a resistor having high heat resistance. In recent years, polyimide resin has been frequently used as a binder resin for applications such as on-vehicle devices because this resin has high heat resistance.
Japanese Patent No. 3372636 (the corresponding U.S. Pat. No. 5,781,100), for example, discloses a method of producing a resistor substrate having excellent heat resistance, less variations in resistance due to heat, and a long life using an acetylene-terminated polyisoimide oligomer having a specific glass transition temperature as a binder resin.
A resistor substrate produced by the above method, however, has the problem that more than 50 million sliding movements cause an increase in contact resistance due to the wearing down of the resistor. On-vehicle sensors, for example, need a potentiometer having the durability to 50 million, or more than 100 million, sliding movements. Resistors included in potentiometers are therefore required to achieve a further improvement in sliding durability.

Sliding resistor having excellent sliding durability

Abstract: wherein n is an integer of zero or more.


Methods and apparatus, including computer program products, are provided for remote monitoring. In some example implementations, there is provided a method. The method may include receiving, at a remote monitor, a notification message representative of an event detected, by a server, from analyte sensor data obtained from a receiver monitoring an analyte state of a host; presenting, at the remote monitor, the notification message to activate the remote monitor, wherein the remote monitor is configured by the server to receive the notification message to augment the receiver monitoring of the analyte state of the host; accessing, by the remote monitor, the server, in response to the presenting of the notification message; and receiving, in response to the accessing, information including at least the analyte sensor data. Related systems, methods, and articles of manufacture are also disclosed.

Diabetes mellitus is a disorder in which the pancreas cannot create sufficient insulin, such as in the case of Type I diabetes and/or in which insulin is not effective, such as Type 2 diabetes. In a diabetic state, a victim suffers from high blood sugar, which causes an array of physiological derangements, such as kidney failure, skin ulcers, or bleeding into the vitreous of the eye, associated with the deterioration of small blood vessels. A hypoglycemic reaction, such as low blood sugar, may be induced by an inadvertent overdose of insulin, or after a normal dose of insulin or glucose-lowering agent accompanied by extraordinary exercise or insufficient food intake.
A diabetic person may carry a self-monitoring blood glucose (SMBG) monitor, which typically requires uncomfortable finger pricking methods. Due to the lack of comfort and convenience, a diabetic typically measures his or her glucose level only two to four times per day. Unfortunately, these time intervals are spread so far apart that the diabetic will likely find out too late, sometimes incurring dangerous side effects, of a hyperglycemic or hypoglycemic condition. In fact, it is not only unlikely that a diabetic will take a timely SMBG value, but additionally the diabetic will not know if his blood glucose value is higher or lower based on conventional methods.
Consequently, a variety of non-invasive, transdermal (e.g., transcutaneous) and/or implantable electrochemical sensors are being developed for continuously detecting and/or quantifying blood glucose values. These as well as other types of devices generally transmit raw or minimally processed data for subsequent analysis at a remote device, which can include a display, to allow presentation of information to a user hosting the sensor.

Remote monitoring of analyte measurements


Spliced structural members for supporting a traffic deck on a short span bridge. A spliced structural member includes a plurality of metal box-shaped girder segments placed end to end and splice channels nested around the adjacent ends of the girder segments. A spliced joint is formed by connecting the splice channels to the adjacent ends of the girder segments. The spliced joint has at least 75% of the flexural and shear strength of the girder segments and provides continuity for structural strength and rigidity for the spliced structural member.

This invention relates to a spliced structural member. More particularly, a plurality of girder segments are placed end to end and splice channels are nested around and connected to the adjacent ends of the girder segments to form a spliced joint in the structural member. The spliced joint has at least 75% of the flexural and shear strength of any one of the girder segments and provides continuity for structural strength and rigidity for the spliced structural member.
It is known that structural members such as beams, girders, columns and the like can be fabricated in various shapes from light weight, structural materials. Box-shaped girder segments are normally manufactured by press brake-forming metal sheet or by cold rolling metal strip into a C-shape configuration and arc or resistance welding a pair of the C-shape members into a box configuration. The length of a span such as in a bridge or a building for which structural members provide load support often exceeds the nominal length of such conventionally produced girder segments. Manufacturing and transportation limitations also restrict the length availability of girder segments.
It is known that girder segments can be structurally joined end to end using splice plates or by welding. Splice plates are bulky, clutter the top surface, time consuming to connect, and impractical to use inside of box-shaped girder segments. All these problems can be overcome when welding capability is available at the job site to splice the girder segments into the required length by butt welding the girder segments end to end. However, field welding conditions are usually poor because welding equipment and qualified welding personnel frequently are unavailable in many remote areas, especially in third world countries.
Accordingly, there remains a long felt need for an improved mechanical splice that is shop fabricated to minimize the time, equipment and skill necessary to assemble a spliced structural member at the jobsite. Furthermore, the spliced structural member must develop high strength and be able to transfer structural strength and rigidity through the spliced joint connecting girder segments. The splice also must be readily transportable and the upper surface of the splice be free of bolts to prevent interference with placement of a bridge deck when the structural member is used as a bridge girder or with placement of a floor, wall or roof deck when the structural member is used as a building frame component.


A label supplying device is provided, whereby false bonding at a cylindrical label's end is reliably released, and ill-timed supplying of the label to the label supply position hardly occurs. The supplying device includes: a material delivery unit (10) for continuously delivering an elongated label base material (M) paid out from a material roll by a pay-out unit; a cutting unit (20) for cutting, at a predetermined pitch, the base material (M) delivered by the delivery unit (10); an upstream and a downstream belt transfer units (30, 40) for transferring labels (L), formed by the cutting of the cutting unit (20), to a label supply position (α); and a separation unit (50) for separating overlapping edges of the upper end of the label (L) (upstream end in the transfer direction of the label (L)) during the transferring of the label (L) by the upstream transfer unit (30).

A labeling system is used for attaching cylindrical labels, such as stretch labels or shrink labels, to the outer body surfaces of various bottles. Such a labeling system is provided with a label supplying device designed to make cuts consecutively in a label base material in the form of an elongated folded sheet to provide closely arranged cylindrical labels. Through the cutting, the label base material is formed into cylindrical labels each having a predetermined length. These cylindrical labels of the predetermined length are forwarded by the label supplying device to the following label attaching device.
As shown in FIG. 18, the label supplying device includes a delivery roller 101 for delivering a label base material M in the form of an elongated folded sheet, a cutting unit 102 for cutting the label base material M delivered by the delivery roller 101 into a predetermined length to form individual cylindrical labels L, and a belt transfer unit 103 for transferring the cylindrical labels L of the predetermined length to a label supply position α. The belt transfer unit 103 transfers the labels L, which are formed by the cutting operation and have a predetermined length, to the label supply position α. For this transfer, the labels L are sucked onto a pair of feed belts 103a, 103a arranged parallel to each other with a predetermined space between them.
As noted above, the long strip-like label base material M is cut into cylindrical labels L. Unfavorably, in each resulting label L, the cut edges at an end falsely stick together. As a result, in opening the folded sheet of the cylindrical label L, the label fails to open properly, and hence, fails to be attached to a bottle smoothly and reliably. To avoid this problem, the label supplying device 100 of this kind includes a label edge separation unit 104 for separating the overlapping edges of the folded sheet of the cylindrical label L during the transferring of the cylindrical label L by the belt transfer unit 103.
As illustrated in the figure, the label edge separation unit 104 is arranged to face the feed belts 103a, 103a across the transfer line of the cylindrical label L, and includes three guide rollers 104a, a driving pulley 104b, and belts 104c, 104c wound around these rollers and pulley. The driving pulley 104b is driven by a servomotor operable independently from the servomotor for circulating the feed belts 103a, 103a.
The rotation speed of the driving pulley 104b is set so that the belts 104c, 104c circulate at a higher speed than that of the feed belts 103a, 103a. The overlapping edges of the cylindrical label L, sandwiched between the belts 104c, 104c and the feed belts 103a, 103a, will be separated from each other due to the difference in speed between the movement of the belts 104c, 104c and that of the feed belts 103a, 103a.


Contrast enhancing exposure apparatus and method for use in semiconductor fabrication are described. In one embodiment, a method for forming a pattern on a substrate, wherein the substrate includes a photoresist layer comprising photoacid generators (“PAGs”) and photobase generators (“PBGs”), is described. The method includes dividing the pattern into two component patterns; exposing the photoresist layer of the substrate to UV light through a first mask corresponding to a first one of the component patterns; subsequent to the exposing the photoresist layer of the substrate to UV light through the first mask, exposing the photoresist layer of the substrate to UV light through a second mask corresponding to a second one of the component patterns, wherein the PAGs and PBGs disposed in areas of the photoresist layer that have been exposed to UV light at least twice are activated and wherein the activated PAGs neutralize the activated PBGs in areas of the photoresist layer that have been exposed to UV light at least twice.

The fabrication of integrated circuits ("ICs") involves the performance of a range of chemical and physical processes on a semiconductor substrate. In general, these processes include deposition, patterning, and doping. Fundamental to all of these processes is lithography by which process three-dimensional relief images are formed on a substrate for subsequent transfer of a pattern to the substrate.
Lithography accounts for a large part of the cost of IC fabrication, due to the large number of lithography steps involved in fabrication. In addition, lithography generally presents the primary limitation to further advancements in the reduction of feature size and silicon area and the increase in transistor speed. Clearly, therefore, a balance must be struck between cost and capability when developing a lithography process.
Optical lithography is a well-known photographic process by which a photoresist layer comprising a polymer product deposited on a substrate is exposed (i.e., irradiated with UV light) and developed to form three dimensional relief images on the substrate. In general, the ideal photoresist image has the exact shape of the intended pattern in the plane of the substrate with vertical walls through the thickness of the resist. Thus, the final resist pattern is binary, with parts of the substrate covered with the resist while other parts are uncovered. Although the polymer product itself may be photoactive, generally a photoresist contains one or more photoactive components in addition to the polymer product. Upon exposure, the photoactive component acts to change the physical or chemical characteristics of the photoresist.
It has been known in the art to use a double exposure process in IC fabrication; however, current double exposure processes require additional developing, film deposition and/or etch process steps or result in a loss of contrast on the photoresist pattern.

Contrast enhancing exposure system and method for use in semiconductor fabrication

Taiwan Semiconductor Manufacturing Company, Ltd.


An object of the invention is to provide thermosetting amic acid microfine particles, thermosetting imide microfine particles and crosslinked imide microfine particles of controlled particle shape and size distribution. The invention provides a production technology which comprises mixing a first solution containing a tetracarboxylic anhydride and a C.dbd.C bond-containing acid anhydride with a second solution containing a diamine compound, causing precipitation of thermosetting amic acid microfine particles from the resulting mixture, and further producing thermosetting imide microfine particles and crosslinked imide microfine particles from the thermosetting amic acid microfine particles.

Imides inclusive of polyimides have good heat resistance, resistance to chemicals, and electric insulating properties in addition to favorable mechanical characteristics so that they have been used not only as electric/electronic materials and automotive materials but also broadly as substitutes for metals and ceramics.
While polyimides are classified by skeletal chain morphology into linear polyimides (thermoplastic type) and three-dimensional network polyimides (thermosetting type), the latter thermosetting polyimides are particularly superior in heat resistance, processability, moldability, etc. and, therefore, are generally acknowledged to be of great use as electrical laminate materials, aerospace materials, and various other molding materials.
As regards the thermosetting imide resin, many versions are known, such as the resin produced by a process starting with a bismaleimide and a diamine compound, as represented by KERIMID (trademark, manufactured by Rhone-Poulenc), and the terminal double bond-containing resin such as the adduct type imide resin represented by the PMR series resin (PMR-11, trademark, manufactured by NASA).
The thermosetting imide resin has been produced typically by the method which comprises reacting a tetracarboxylic dianhydride and an acid anhydride having a carbon-carbon double bond with an organic diamine compound in an organic solvent generally at a temperature of 0.about.100.degree. C. to prepare a thermosetting amic acid solution, pouring this solution in a nonsolvent for the thermosetting amic acid, recovering the resulting precipitate, and subjecting it to cyclization for imidation.
However, when thermosetting imide resin microfine powders are to be produced from a thermosetting amic acid solution as in the above method, the resin block recovered following said imidation reaction must be pulverized by mechanical means, which adds to the complexity of the process. Moreover, a procedure by mechanical pulverization yields only coarse particles so that a monodispersed system of fine discrete particles can hardly be obtained. In addition, by the above production technology, the shape and size distribution of particles can hardly be controlled. For these reasons, there has been a persistent demand for the development of a technology for producing microfine particles of a thermosetting imide with good monodispersibility and other favorable characteristics.
An object of the present invention, therefore, is to provide thermosetting amic acid microfine particles, thermosetting imide microfine particles and crosslinked imide microfine particles each well-controlled in shape and size distribution.

Thermosetting amic acid microfine particles, thermosetting imide microfine particles, crosslinked imide microfine particles, and processes for their production


A post-processing apparatus is connected to an image forming apparatus that forms an image on a sheet. The post-processing apparatus includes a post-processor, a sensor, and a controller. The post-processor performs post-processing on the sheet. The sensor is provided in a space where the post-processor operates and provides an output based on a presence of a foreign substance in the space. The controller acquires a first output value from the sensor prior to the image forming apparatus forming the image on the sheet, acquires a second output value from the sensor after the image forming apparatus forms the image on the sheet and before the post-processor performs the post-processing on the sheet, and determines whether or not the foreign substance is present in the space based on the first output value and the second output value.

In the related art, there is an image forming apparatus that performs post-processing such as stapling after forming an image on a sheet. Such an image forming apparatus is provided with a space for executing the post-processing. Since the sheet is discharged after executing the post-processing, the space for executing the post-processing is connected to the outside. Therefore, when a foreign substance intrudes into the space from the outside, there is a possibility that the post-processing apparatus is broken.

Post-processing apparatus and control method


In one embodiment, techniques approximate concurrent monitoring of a large number of geo-fences, potentially beyond a number supported by a mobile device, The mobile device may obtain a set of geo-fences and maintain a first subset of the geo-fences as an active subset of geo-fences and a second subset of the geo-fences as an inactive subset of geo-fences. The mobile device may also establish and monitor an envelope geo-fences that excluded the inactive subset of geo-fence. In response to detecting that the mobile device has moved to a new location proximate to the envelope geo-fence, one or more geo-fences are moved between the active subset of geo-fences and the inactive subset of geo-fences to produce a new active subset of geo-fences and a new inactive subset of geo-fences.

Technical Field
The present disclosure relates generally to location-based services, and more specifically to geo-fences.
Background Information
Location-based services are a field of mobile applications that leverage the ability of many mobile devices to determine their current location and perform actions based on that location. Location-based services may involve supplying location-dependent content (e.g., advertisements, weather forecasts, driving directions, traffic updates, or other content) on the mobile device itself, providing location information for the mobile device to other devices (e.g., to enable "buddy" finding, child monitoring, or other services), collecting location-based statistical information (e.g., consumer demographic data, traffic data, or other data), or other types of operations.
Some location-based services utilize geo-fences. A geo-fence is a virtual perimeter that may be established around a real-world geographic area. Crossing a geo-fence may cause a service to be provided, cause a service to be withheld, or trigger some other sort of action, depending on the particular application. However, there are several shortcomings in the present implementation of geo-fences on many mobile devices. Two prominent shortcomings involve limits on the number of geo-fences that a mobile device may concurrently monitor, and restrictions on the shape and/or size of geo-fences that the mobile device may monitor.
In order to support geo-fences, mobile devices typically repeatedly determine their current location and compare that location to the virtual perimeter defined by the geo-fence. Such location determination and comparison consumes resources of the mobile device, including processing resources, and, often more importantly, power resources. Given the importance of battery life for many mobile devices, there may be practical limits on how many geo-fences can be concurrently monitored. In some cases, these practical limits are codified into restrictions imposed by the mobile device's operating system or firmware. For example, some mobile devices currently allow concurrent monitoring of about 20 geo-fences for a given application and about 100 geo-fences across all applications. These geo-fence limits are becoming increasingly problematic, as geo-fences are being utilized in more and more location based services. However, increasing these limits has proven difficult, given the compelling desire to even further reduce power consumption of mobile devices.
Further, in order to simplify processing and achieve other efficiencies, some mobile devices impose limits on the possible shapes and sizes of monitored geo-fences. While geo-fences may theoretically be defined to have any of a wide variety of shapes and sizes, some mobile devices only support monitoring of geo-fences having certain supported shapes and sizes. For example, a mobile device may only support circular-shaped geo-fences having a radius of 100 meters. This limitation is becoming increasingly burdensome on developers and users, who may desire to utilize geo-fences having shapes and/or sizes other than those natively supported.
Accordingly, there is a needed for improved techniques that may allow for monitoring of a number of geo-fences beyond a mobile device's geo-fence limit, and for using geo-fences of shapes and/or sizes other than those natively support by the mobile device.


There is provided a connector capable of realizing simple assembly and prevention of entering of foreign matter. A connector terminal (56) includes an insertion part (56a) that has a terminal metal fitting to be electrically connected with an external connection terminal, and a pin (56d) fixed to the insertion part (56a) and has a bent shape. The connector terminal (56) is held by a connector housing (55). In this situation, the connector housing (55) has a hole (57) that has a size at which the pin (56a) can penetrate from a tip side, and a guide wall (57d) formed along an outer circumference of the hole (57) and projects in a direction in which the pin (56d) projects from the connector housing (55).

The technique disclosed in PTL 1 is described, for example, as a connector of the related art. The purpose of this technique is to prevent dew condensation around a terminal of a connector, so a wall that blocks a gap part created when a connector housing is mounted on a substrate is formed in the connector housing. In such a situation, the wall is partially arranged (i.e., discontinuously on a connector outer circumference).
In addition, the technique disclosed in PTL 2 is described, as another example. In this technique, a terminal is press-fit into a connector housing, so that a projection that prevents molding material leakage from the interior is fit into the connector housing for providing a creepage distance. In such a situation, the wedge-shaped projection is disposed midway on the terminal, and the projection and a concave part disposed in the connector housing are fit into each other.


Systems and methods for requesting modification of traffic flow control systems that combine satellite position navigation systems and dead reckoning technology with secure radio communications to accurately report a vehicle's real-time location and estimated arrival times at a series of signal lights within a traffic grid or at a distant signal light, while enabling signal controllers to accommodate priority requests from these vehicles, allowing for these vehicles to maintain a fixed schedule with minimal interruption to other grid traffic.

1. Field of the Invention
This disclosure is related to the field of systems for the management of traffic flow through the controlling of signal lights and monitoring the location of vehicles within a traffic grid.
2. Description of Related Art
In the perfect commuter utopia, signal lights would automatically switch to green every time a driver's vehicle approached an intersection, creating an unobstructed pathway towards the driver's final destination. In real life though, hitting a red light is a normal and inevitable part of any driver's commute. With the growth of modem cities and the reliance of much of the population on mass transit and personal automobiles for transportation, efficient control of the ebb and flow of traffic through efficient and smart signal light control and coordination systems has become increasingly important.
There are many substantial benefits to be reaped from improved traffic flow for personal, mass transit, and emergency motor vehicles. For many commuters, reclaiming part of their day would enhance their quality of life. Further, less congestion on the roads would generate fewer accidents, thereby saving lives. Moreover, traffic delays impinge on productivity and economic efficiency—time spent traveling to and from work is not time spent doing work. Further, many goods must be transported and many service providers must travel to their clients. Traffic delays all of these economic production factors. There is also a concern regarding the increased pollution that results from stop-and-go traffic flow in contrast to smooth flowing traffic. Further, longer commutes means longer running times and entails more greenhouse gases. Also, congested traffic and uncoordinated signal lights can cause delays in the mass transit system which, if not remedied, can throw off an entire mass transit schedule grid and disincentivise individuals from using mass transit systems. For example, it has been demonstrated that schedule adherence for mass transit vehicles results in an increase in ridership. Lastly, the importance of prioritizing and efficiently moving emergency vehicles through traffic lights is axiomatic.
Currently, a variety of different control and coordination systems are utilized to ensure the smooth and safe management of traffic flows. One commonly utilized mechanism is the traffic controller system. In this system, the timing of a particular signal light is controlled by a traffic controller located inside a cabinet which is at a close proximity to the signal light. Generally, the traffic controller cabinet contains a power panel (to distribute electrical power in the cabinet); a detector interface panel (to connect to loop detectors and other detectors); detector amplifiers; a controller; a conflict motor unit; flash transfer relays; and a police panel (to allow the police to disable and control the signal), amongst other components.
Traffic controller cabinets generally operate on the concept of phases or directions of movement grouped together. For example, a simple four-way intersection will have two phases: North/South and East/West; a four-way intersection with independent control for each direction and each left hand turn will have eight phases. Controllers also generally operate on the concept of rings or different arrays of independent timing sequences. For example, in a dual ring controller, opposing left-turn arrows may turn red independently, depending on the amount of traffic. Thus, a typical controller is an eight-phase, dual ring controller.
The currently utilized control and coordination systems for the typical signal light range from simple clocked timing mechanisms to sophisticated computerized control and coordination systems that self-adjust to minimize the delay to individuals utilizing the roadways.
The simplest control system currently utilized is a timer system. In this system, each phase lasts for a specific duration until the next phase change occurs. Generally, this specific timed pattern will repeat itself regardless of the current traffic flows or the location of a priority vehicle within the traffic grid. While this type of control mechanism can be effective in one-way grids where it is often possible to coordinate signal lights to the posted speed limit, this control mechanism is not advantageous when the signal timing of the intersection would benefit from being adapted to the changing flows of traffic throughout the day.
Dynamic signals, also known as actuated signals, are programmed to adjust their timing and phasing to meet the changing ebb and flow in traffic patterns throughout the day. Generally, dynamic traffic control systems use input from detectors to adjust signal timing and phasing. Detectors are devices that use sensors to inform the controller processor whether vehicles or other road users are present. The signal control mechanism at a given light can utilize the input it receives from the detectors to adequately adjust the length and timing of the phases in accordance with the current traffic volumes and flows. The currently utilized detectors can generally be placed into three main classes: in-pavement detectors, non-intrusive detectors, and detectors for non-motorized road users.
In-pavement detectors are detectors that are located in or underneath the roadway. These detectors typically function similarly to metal detectors or weight detectors, utilizing the metal content or the weight of a vehicle as a trigger to detect the presence of traffic waiting at the light and, thus, can reduce the time period that a green signal is given to an empty road and increase the time period that a green signal is given to a busy throughway during rush hour. Non-intrusive detectors include video image processors, sensors that use electromagnetic waves or acoustic sensors that detect the presence of vehicles at the intersection waiting for the right of way from a location generally over the roadway. Some models of these non-intrusive detectors have the benefit of being able to sense the presence of vehicles or traffic in a general area or virtual detection zone preceding the intersection. Vehicle detection in these zones can have an impact on the timing of the phases. Finally, non-motorized user detectors include demand buttons and specifically tuned detectors for detecting pedestrians, bicyclists and equestrians.
Above and beyond detectors for individual signal lights, coordinated systems that string together and control the timing of multiple signal lights are advantageous in the control of traffic flow. Generally, coordinated systems are controlled from a master controller and are set up so that lights cascade in sequence, thereby allowing a group or "platoon" of vehicles to proceed through a continuous series of green lights. Accordingly, these coordinated systems make it possible for drivers to travel long distances without encountering a red light. Generally, on one-way streets this coordination can be accomplished with fairly constant levels of traffic. Two-way streets are more complicated, but often end up being arranged to correspond with rush hours to allow longer green light times for the heavier volume direction. The most technologically advanced coordinated systems control a series of city-wide signal lights through a centrally controlled system that allows for the signal lights to be coordinated in real-time through above-ground sensors that can sense the levels of traffic approaching and leaving a virtual detection zone which precedes a particular intersection.
While cascading or synchronized central control systems are an improvement on the traditional timer controlled systems, they still have their drawbacks. Namely, priority vehicles in these systems are only able to interact with a virtual detection zone immediately preceding a particular intersection; there is no real-time monitoring of the traffic flows preceding or following this virtual detection zone across a grid of multiple signal lights. Stated differently, there is no real-time monitoring of how a vehicle or a group of vehicles travels through a traffic grid as a whole (i.e., approaching, traveling through and leaving intersections along with a vehicle's transit between intersections). Accordingly, these systems can provide for a priority vehicle, such as an emergency vehicle, to be accelerated through a particular signal at the expense of other vehicles, but they lack the capability to adapt and adjust traffic flows to keep a mass transit vehicle, or similar time scheduled vehicle, on time or adjust the lights in front of a mass transit vehicle to get it back on schedule. Virtual detection zone based systems only have the capability for control of a particular signal light to accelerate the movement of a single vehicle or a group of vehicles approaching that signal directly; they cannot offer an integrated control system with the capability of controlling the phases of multiple signal lights in a grid system, altering the length of particular phases at particular signal lights within the grid system to accommodate a particular vehicle traveling through the grid system according to a relatively fixed path and schedule.
Another problem with virtual detection zone based systems is their disruption of the overall traffic flow of the grid. As noted previously, detection zone based systems are focused on individual signal lights. If a priority vehicle is sensed in the virtual detection zone, the immediately upcoming light will either change to green to give the priority vehicle the right-of-way and potentially disrupt the entire system (something logical for allowing rapid passage of an emergency vehicle) or will not because the vehicle lacks sufficient priority to disrupt the system (as can be the case with a mass transit vehicle) simply to beat the next signal.
What detection zone based systems fail to take into account is the impact this immediate change in an immediately approached signal light phase, irrespective of other traffic at the light, has on the overall traffic flows of the grid as a whole. Thus, while aiding in getting a particular priority vehicle through an intersection, these systems can, on a broader basis, add to rather than decrease the traffic levels in a given area at a given time. Further, because of their focus on a single signal light and vehicles approaching a single signal light, these systems are generally incapable of adjusting a series of lights within the traffic grid based upon a vehicle's current position, speed, schedule and path of travel.
Another frequent traffic problem which cannot be addressed by these commonly utilized virtual detection zone based systems is mass transit vehicle bunching, also known as bus bunching, clumping or platooning. Bunching refers to a group of two or more transit vehicles along the same route, which are scheduled to be evenly spaced, such as buses, catching up with each other and, thus, running in the same location at the same time. Generally, bunching occurs when at least one of the vehicles is unable to keep to its schedule and therefore ends up in the same location as one or more other vehicles on the same route. Thus, the lead mass transit vehicle in the bunch typically slows to pick up passengers that would otherwise be boarding the trailing mass transit vehicle. This leads to overcrowding and further slowing of the lead vehicle. Conversely, the trailing mass transit vehicle encounters fewer passengers and, soon, both mass transit vehicles are in full view of each other—to the dismay of passengers on the overcrowded and behind schedule vehicles. It is no surprise that bunching is a leading complaint of regular transit riders and a headache for those operating and managing transit services. The currently utilized detection zone based systems—with their control methodology localized to individual lights—are simply incapable of controlling or preventing bunching.
Another failing of the currently utilized detection zone based systems is their inability to modify the conditions under which a vehicle may request priority. For example, under many of these currently utilized systems, priority is given to any flagged vehicle that enters a detection zone and is sensed by a detector (such as an in-pavement detector). These systems are generally incapable of granting priority on a more nuanced and conditional basis such as only granting priority when another mass transit vehicle has not requested priority within a specified time frame or only granting priority when an exit request has not been made for the next stop.
Thus, there is a need in the art of traffic flow management for a system that is capable of controlling and adjusting signal lights based on the movement, position and proposed schedules of one or more tracked vehicles within a traffic grid.

Signal light priority system utilizing estimated time of arrival