A shot block for use in a die casting machine for die casting molten and semi-molten metal parts is formed from a metal or metal alloy having a thermal conductivity of at least about 25 Btu/ft.hr.xc2x0 F., a Rockwell C hardness of at least about 25 and a 0.2% Yield Strength of at least about 90 ksi.

1. Field
The present invention relates to die casting and in particular to new shot blocks for use in die casting and other similar casting operations.
2. Background
Die casting, which is also known as xe2x80x9cpressure die castingxe2x80x9d and xe2x80x9csqueeze casting,xe2x80x9d is a well known casting process in which molten metal is forced under high pressure into permanent steel dies. See Metals Handbook, (copyright)1985 American Society for Metals, pages 23*32 to 23*41, the disclosure of which is incorporated herein by reference. xe2x80x9cThixoforgingxe2x80x9d or xe2x80x9cthixoformingxe2x80x9d are similar processes in which the metal being cast is in a semi-solid state (i.e. a solid/liquid mixture) rather than in purely molten form.
In conventional die casting and thixoforming operations, a piston or like device forces the metal being cast into the die through one or more passageways or xe2x80x9crunnersxe2x80x9d which are connected to a manifold for receiving the pressurized metal. Thus, a conventional die casting machine typically includes a die composed of a cover die half and an ejector die half. The cover die half and the ejector die half mate with one another along a separation surface and together define multiple die cavities. The cover die half is stationary, while the ejector die half is movable so that when a molten charge solidifies, the ejector die half can be moved apart from the cover die half so that the solidified charge in each mold cavity can be removed.
Molten or semi-molten metal to be cast is charged into the die cavities by a charging assembly which includes a pressure cylinder for receiving molten metal from an inlet, a piston movable in the pressure cylinder for forcing the molten metal into the die cavities, and a shot block made from conventional tool steel mounted in or on the cover die half of the die. The shot block defines a manifold or reservoir for receiving molten metal from the pressure cylinder and supplying this molten metal to the die cavities via passageways or xe2x80x9crunnersxe2x80x9d defined in the separation surface between the cover die half and the ejector die half of the die. Flow passageways are normally provided in the shot block for cooling the metal in the reservoir by indirect heat exchange using water, hot oil or other liquid as the cooling medium.
Because molten metal shrinks as it solidifies, it is important that additional amounts of molten metal be continuously supplied at high pressure to the mold cavities until enough metal in these cavities has solidified. To this end, the reservoir in the shot block as well as the runners are normally designed to be large enough so that at least some metal in these locations is still molten when the necessary degree of solidification has been reached in the mold cavities. In actual practice, this often means that the metal in the reservoir (typically referred to as a xe2x80x9cbiscuitxe2x80x9d) will still be molten, or at least partially molten, when the metal in the mold cavities has completely solidified.
Once the metal in the mold cavities has solidified, the mold halves are separated from one another and the solidified castings in these cavities removed for further processing. However, for safety reasons, this cannot be done until the metal in the reservoir of the shot block has also solidified substantially. In this connection, it has been found that the metal in the shot block reservoir, since it is present under high pressure, can actually explode if the mold halves are opened too soon. Therefore, care must be taken to insure that the metal in the shot block reservoir solidifies sufficiently before the mold halves are separated from one another.
In modern industrial practice, it is always desirable to increase efficiency. To this end, commercial die casting machines such as described above are typically operated with as little cycle time as possible. In other words, the time between successive casting cycles is minimized to the greatest extent possible. Unfortunately, the time it takes molten metal in the shot block reservoir to solidify sufficiently represents the constraining factor in achieving shorter cycle times in 25 to 50% of commercial die casting operations.
Accordingly, there is a need for new technology which enables shorter cycle times to be achieved yet still allows the metal biscuit in the reservoir to solidify sufficiently before the mold halves are separated.
In accordance with the present invention, it has been found that the cycle times of die casting and like machines can be considerably shortened, while still allowing the metal biscuits in the shot block reservoirs of such machines to solidify sufficiently, by forming the shot blocks used in such machines from metal or metal alloys having a thermal conductivity of at least about 25 Btu/ft.hr.xc2x0 F., a Rockwell C hardness of at least about 25 and a 0.2% Yield Strength of at least about 90 ksi.
Thus, the present invention provides a new shot block for use in die casting molten and semi-molten metal parts wherein the shot block is formed from a metal or metal alloy having a thermal conductivity of at least about 25 Btu/ft.hr.xc2x0 F., a Rockwell C hardness of at least about 25 and a 0.2% Yield Strength of at least about 90 ksi.
In addition, the present invention also provides a new die casting machine including a die, a pressure cylinder for supplying molten or semi-molten metal to the die under pressure and a shot block defining a reservoir for transferring the molten or semi-molten metal received from the pressure cylinder to the die, characterized in that the shot block is made form from a metal or metal alloy having a thermal conductivity of at least about 25 Btu/ft.hr.xc2x0 F., a Rockwell C hardness of at least about 25 and a 0.2% Yield Strength of at least about 90 ksi.
In accordance with the present invention, conventional die casting machines and other like pieces of equipment for charging molten or semi-molten metals into dies under high pressure are equipped with shot blocks made from metals or metal alloys having a thermal conductivity of 25 Btu/ft.hr.xc2x0 F., a Rockwell C hardness of at least 25 and a 0.2% Yield Strength of at least 90 ksi. Therefore, the shot block in the apparatus described above, rather than being made from H13 tool steel or other conventional alloy, is made from an alloy having this combination of properties.
Properties of Metals Used in Forming Inventive Shot Block
An important feature of the metals or alloys used in making shot block 30 in accordance with the present invention is that they have thermal conductivities of at least about 25 Btu/ft.hr.xc2x0 F., preferably at least about 37 Btu/ft.hr.xc2x0 F. Metals or alloys having thermal conductivities of at least about 60 Btu/ft.hr.xc2x0 F. are more interesting, while metals or alloys having thermal conductivities of at least about 145 Btu/ft.hr.xc2x0 F. are of special interest. H13 tool steel, which is the material from which shot blocks are typically made, has a thermal conductivity of about 15 Btu/ft.hr.xc2x0 F., which is about half that of the metals forming the inventive shot blocks or less. Surprisingly, it has been found that this difference allows the inventive shot blocks to provide a more rapid cooling of the metal biscuit in the shot block reservoir, and hence a faster solidification of this metal biscuit, even though the same type and amount of cooling liquid is used to cool the shot block during the casting operation. This, in turn, allows cycle times to be significantly shortened while still maintaining all other structural and operating features of the casting operation the same.
A second important features of the metals and alloys used to form the inventive shot block is that they have a Rockwell C hardness of at least about 25. A common problem associated with conventional shot blocks is that they show significant amounts of surface crackingxe2x80x94i.e., small cracks with an average maximum crack length of about 0.080 inch and a total crack area of about 0.8 in2. In accordance with the present invention, it has been found that this problem is substantially eliminated by making the inventive shot blocks from metals and alloys which have a Rockwell C hardness of at least about 25 in addition to the thermal conductivities mentioned above. In particular, it has been found that the shot blocks made in accordance with the present invention show about {fraction (1/10)} (10%) of the surface cracking of conventional shot block made from H13 tool steel, when operated under essentially the same conditions. Metals and alloys having Rockwell C hardnesses of at least about 30, and especially at least about 35, are particularly interesting.
The metals and alloys used to form the inventive shot block should also have a strength comparable to that of the H13 tool steel used to make conventional shot blocks. Accordingly, these metals and alloys should have a 0.2% Yield Strength of at least about 90 ksi at room temperature. Metals and alloys with 0.2% Yield Strengths of at least about 100, and even 120 ksi are especially interesting.
Another desirable feature of the metals and alloys used to form the inventive shot block is that they exhibit good resistance to softening at elevated temperature. Some metals lose strength and/or hardness after repeated and/or prolonged exposure to elevated temperatures. Even H13 tool steel loses hardness and strength properties after repeated die casting cycles, at least with respect to processing most materials. The metals and alloys used to form the inventive shot block preferably exhibit a resistance to softening at elevated temperature which is at least as good as that of H13 tool steel and, more desirably even better than that of H13 tool steel.
Still another important feature of the metals and alloys used to form the inventive shot block is that they exhibit good machinability, as this makes fabrication considerably less expensive. Metals and alloys at least 50% more machinable than H13 tool steel as determined by ASTM E618 are desirable, while at least twice as machinable as determined by this test method are especially desirable.
Still another desirable feature in the metals and alloys used to form the inventive shot block is that they exhibit appropriate thermal expansion properties. Since the inventive shot blocks will be mounted in or on other steel parts, it is desirable that the metals and alloys forming the inventive shot blocks have a coefficient of thermal expansion which is similar to that of the steel parts on which the shot blocks will be mounted. Accordingly, the metals and alloys used to form the inventive shot block should preferably have a coefficient of thermal expansion which does not differ from the coefficient of expansion of H13 tool steel by more than 50% in either direction. In other words, it should not be more than 50% greater than the coefficient of expansion of H13 tool steel or less than 50% of the coefficient of expansion of H13 tool steel.
Still another desirable feature in the metals and alloys used to form the inventive shot block is limited porosity. In particular, these metals and alloys should have a porosity corresponding to a density of at least 90% of theoretical in order to provide the necessary heat transferability, strength and structural integrity. Porosities of at least 95 and at least 98% of theoretical density are desirable. In many instances, the inventive shot blocks will be made by conventional casting of molten alloys. In these cases, the shot blocks produced will normally have porosities of 100% of theoretical, as they will be completely solid. In other instances, however, the inventive shot blocks can be produced by powder metallurgy and other techniques which can introduce significant porosity into the products obtained. Accordingly, it is desirable in accordance with the present invention that shot blocks made by such techniques be processed to have porosities of at least about 90% of theoretical and preferably even more.
Still another desirable feature of the metals and alloys used to form the inventive shot block is that they be unreactive to the molten metal being cast. Welding or soldering of a metal being cast to a metal die used in the molding operation can often be a problem. Such problems are normally resolved by changing the chemical composition of the metal being cast, the metal forming the die, or both. Alternatively, such problems can be resolved by modifying the surface of the shot block to minimize unwanted reactions with the metal to be cast, such as by coating or other technique. Obviously, the inventive shot block should also be formed from a metal or alloy which does not undergo unwanted reactions with the metal to be cast, or which can be surface modified so as not to undergo unwanted reactions with the metal to be cast, to any significant degree. This can easily be determined by routine experimentation.
The metals and alloys used to form the inventive shot block are also desirably resistant to corrosion from the water, hot oil or other fluid used for cooling purposes. Stress corrosion cracking can occur in the cooling passageway surfaces if these surfaces begin to corrode, and so it is desirable that these metals and alloys also resist such corrosion. Similarly, it is also desirable that these metals and alloys do not promote, but instead preferably retard, any biological growth that may occur in the cooling passages during exposure to these fluids.
Precipitation Hardenable Alloys
A wide variety of different metals and alloys satisfy the above criteria and hence are useful in making the inventive shot blocks. Examples include the precipitation hardenable alloys containing at least 25 wt. % of a base metal selected from aluminum, nickel, iron, copper, silver, gold, magnesium and titanium. Particular examples are aluminum-beryllium, copper-niobium, nickel-beryllium alloys and the like. These alloys are described, for example, in the following patent applications and patents, the disclosures of which are incorporated herein by reference: Ser. No. 09/387,894, filed Sep. 1, 1999 (20721/04404), Serial No. PCT/US 00/24278, filed Sep. 1, 2000 (20721/04426) and Ser. No. 09/797,465, filed Mar. 1, 2001 (20721/04425).
A particularly useful alloy in connection with the present invention is composed of a base metal comprising copper, nickel or aluminum plus up to about 75 wt. % beryllium. Preferred alloys of this type include at least about 90 wt. % base metal and up to about 10 wt % Be and especially those containing at least about 95 wt. % base metal and up to 5 wt. % Be, and even up to about 3 wt. % Be. Especially preferred are copper alloys containing about 0.3 to 3.3 wt. % Be, nickel alloys containing about 0.4 to 4.3 wt. % Be and aluminum alloys containing about 1 to 75 wt. % Be. The addition of as little as 0.05 wt. % Be to these base metals produces dramatic enhancements in a number of properties including strength, oxidation resistance, castability, workability, electrical conductivity and thermal conductivity making them ideally suited for use in the present invention. Be additions on the order of at least 0.1 wt. %, more typically 0.2 wt. % are more typical.
These alloys may contain additional elements such as Co, Si, Sn, W, Zn, Zr, Ti, Al, Nb, Mn, Mg, Mo, C, Cr, Fe, Y, RE""s and others usually in amounts not exceeding 10 wt. %, preferably not exceeding 2 wt. %, or even 1 wt. %, per element. In addition, each of these base metal alloys can contain another of these base metals as an additional ingredient. For example, the Cuxe2x80x94Be alloy can contain Ni, Co, Zr and/or Al as an additional ingredient, again in an amount usually not exceeding 30 wt. %, more typically no more than 15 wt. %. Usually such alloys will have no more than 2 wt. %, and even more typically no more than 1 wt. % of this additional element.
These alloys are described, generally, in Harkness et al., Beryllium-Copper and Other Beryllium-Containing Alloys, Metals Handbook, Vol. 2, 10th Edition, (copyright)1993 ASM International, the disclosure of which is incorporated by reference herein.
A preferred class of this type of alloy is the C81000 series and the C82000 series of high copper alloys as designated by the Copper Development Association, Inc. of New York, N.Y.
Another preferred class of these alloys are the lean, high conductivity, stress-relaxation resistant BeNiCu alloys described in U.S. Pat. No. 6,001,196, the disclosure of which is also incorporated herein by reference. These later alloys contain 0.15 to 0.5 wt. % Be, 0.4 to 1.25 wt. % Ni and/or Co, 0 to 0.25 wt. % Sn and 0.06 to 1.0 wt. % Zr and/or Ti. Another preferred class of alloys can be described as containing more than 1.5 wt. % Be, with the balance being composed mainly of copper and other elements.
The excellent physical properties of the above alloys arise through a precipitation-hardening mechanism in which fine beryllide precipitates form in the base metal matrix. So long as beryllium is present in an appropriate amount, a small but suitable portion of this beryllium forms base metal beryllide precipitates of small particle size during precipitation hardening. These small precipitate particles uniformly distribute in the base matrix, thereby enhancing its strength. If too much beryllium is present, exceeding the solid solubility limit of beryllium in the base metal, the excess beryllium forms primary nickel beryllide particles, 1 xcexcm in diameter or larger, during solidification. These serve no useful purpose in increasing the strength of the alloys, and may have a detrimental effect on the fracture resistance of the alloys, since they become preferred sites for nucleation of voids. Therefore, the amount of beryllium in the alloy should not be so much that the alloy becomes too brittle or weak, as a practical matter, from formation of large primary base metal-beryllium intermetallic particles.
Forming useful products from ingots of the above precipitation hardenable alloys typically involves a series of heating and working steps to impart the desired shape, grain structure and properties to the alloy. These steps in the aggregate can be considered as constituting
(a) a shaping regimen for changing the bulk shape of the alloy as derived from the ingot into a shape approaching the final desired shape of the product (a xe2x80x9cnear net shapexe2x80x9d) and also for imparting a finer, more nearly uniform grain structure to the alloy, and
(b) a precipitation hardening regimen for nucleating and growing the fine nickel beryllide precipitates responsible for hardening.
Commercially, the shaping regimen involves one or more working steps and solution heat treatment steps (homogenization and/or annealing). Homogenization and annealing are typically done by heating the alloy near but below its solidus temperature to dissolve alloy solute elements in the alloy matrix, thereby achieving a more nearly uniform distribution of ingredients.
Working can be done either at elevated temperatures (xe2x80x9chot workingxe2x80x9d) or at lower temperatures such as room temperature (xe2x80x9ccold workingxe2x80x9d). Both working and annealing may be done multiple times, especially if change in shape is large, with a final solution anneal usually being done last.
Precipitation hardening is accomplished by heating the alloy at a fairly narrow temperature range roughly midway between the solvus temperature and room temperature for 0.5 to 20 hours. Precipitation hardening temperatures approaching the solvus temperature are usually avoided, since it is difficult to control the results obtained at these higher temperatures and the nature of the precipitates changes significantly. Precipitation hardening at less than a minimum practical hardening temperature at which precipitation hardening is too slow to be commercially feasible is also avoided. In general, each precipitation hardenable alloy has its own particular time/temperature combination leading to maximum hardness, meaning that if the alloy is heated either too little or too much its hardness and other properties are less than optimal, Thus, it is conventional to refer to such alloys as being xe2x80x9cpeak agedxe2x80x9d if age hardened at or near optimal time/temperature conditions, or as underaged or overaged if heated too little or too much.
Additional Alloys
Another type of alloy that can be used in making the inventive shot block is the alloy known as xe2x80x9cAnviloy,xe2x80x9d which is a tungsten-based alloy containing at least about 80 wt. % tungsten, at least about 1 wt. % molybdenum and one or more additional elements such as iron and nickel.
A different but related alloy that can also be used in the present invention, designated as xe2x80x9cTZM,xe2x80x9d is a molybdenum based alloy containing at least about 80 wt. % molybdenum, and small amounts of titanium, zirconium or both. Specific examples of such alloys are as follows:
Spinodal Alloys
Another class of alloys that is especially useful in making the inventive shot blocks is the spinodal alloysxe2x80x94i.e., alloys which spinodally decompose upon age hardening. A particularly interesting group of alloys of this type is the Cuxe2x80x94Nixe2x80x94Sn spinodal alloys. These alloys, the most commercially important of which contain about 8 to 16 wt. % Ni and 5 to 8 wt. % Sn with the balance being Cu and incidental impurities, spinodally decompose upon final age hardening to provide alloys which are both strong and ductile as well as exhibiting good electrical conductivity, corrosion resistance in Clxe2x88x92, wear resistance and cavitation erosion resistant. In addition, they are machinable, grindable, platable and exhibit good non-sparking and anti-galling characteristics. These alloys are described in U.S. Application Ser. 08/552,582, filed Nov. 3, 1995 (corresponds to New Zealand Patent No. 309290), the disclosure of which is also incorporated by reference. Especially preferred alloys of this type include those whose nominal compositions are 15Ni-8Snxe2x80x94Cu (15 wt. % Ni, 8 wt. % Sn, balance Cu) and 9Ni-6Snxe2x80x94Cu, which are commonly known as Alloys UNS C72700, C72900, C96800 and C96900 under the Unified Numbering System of the Copper Development Association. In addition to Ni and Sn, these alloys may also contain additional elements for enhancing various properties in accordance with known technology as well as incidental impurities. Examples of additional elements are B, Zr, Mn, Nb, Mg, Si, Ti and Fe.
In a particularly advantageous application of the present invention, the inventive shot blocks are made Nixe2x80x94Snxe2x80x94Cu spinodal alloys described in the above-noted U.S. Application Ser. No. 08/552,582 (New Zealand Patent No. 309,290) by the continuous casting technology also described in that application. In this technology, molten alloy is introduced into a continuous casting die in such a manner that turbulence is created at the liquid/solid interface. Because of this xe2x80x9cturbocastingxe2x80x9d procedure, a finer, more nearly uniform grain structure is achieved than possible before. As a result, the castings so obtained can be directly precipitation hardened without wrought processing first, as normally done when products formed from conventional precipitation hardenable alloys are made. Because wrought processing has been eliminated, products can be made in bigger sizes and/or more complex shapes than possible before. This can represent a significant advantage in making the inventive shot blocks, which may be large in size or complex in shape depending on the particular application in which they will be used.
In an especially preferred embodiment of this invention, shot blocks made in this manner are subjected to the hot isostatic pressing technology described in the above-noted Ser. No. 09/797,465 (20721/04425). In this technology, turbocast ingots made from the above Nixe2x80x94Snxe2x80x94Cu spinodal alloys are subjected to hot isostatic pressing preferably before spinodal decomposition. This enables even better properties to be achieved in final products with bigger sizes and/or more complex shapes.
Powder Metallurgy
In addition, to making the inventive shot blocks by casting techniques, as described above, the inventive shot blocks can also be made by powder metallurgy techniques as well. In these techniques, a xe2x80x9cgreen compactxe2x80x9d having a shape approximating the shape of the final desired product is made by compacting a mass of alloy powder under high pressure. The compact is then heated, during or after compaction, to cause contiguous particles to fuse to one another, thereby producing a final product of the desired shape and chemical composition. Depending on how the process is carried out, products having densities up to 100% of theoretical can be produced.
This preparation method can also be used to advantage in making the inventive shot blocks, especially those having large and/or complex shapes.


A scanning display system includes smart infrared pulsing to detect gestures and touch events with reduced power consumption. Infrared laser light pulses are emitted at a first density in a field of view and reflections are detected. Times of flight of the infrared laser light pulses are measured to determine if an object is in the field of view. The density of the infrared pulses may be increased based on various factors to detect gestures and touch events. Power consumption is reduced by reducing the density of laser pulses when possible.

Interactive scanned beam display systems typically acquire data that relates to the position or movement of pointing objects in the field of view of the display. The data relating to the pointing objects is then mapped to events that can be consumed by a processing device. For example, pointing object data may be mapped to gestures, touch events, mouse clicks, or the like.
Increased resolution, accuracy, and range can be achieved by increasing power output and/or receive gain, both of which result in increased power consumption, and/or opto-mechanical design complexity, which may not be desirable.

Scanning time of flight 3D sensing with smart pulsing


An electric caulking gun may include a cartridge setting portion to which a cartridge containing a caulking material can be set, an electric motor, a push rod driven by the electric motor via a power transmission path and configured to be pressed against the cartridge for dispensing the caulking material from the cartridge, and an interruption device provided in the power transmission path and operable for interrupting the power transmission path and allowing the push rod to be freely moved.

1. Field of the Invention
This invention relates to filling tools (so-called caulking guns) used mainly for repairing operations of building materials or the like for the purpose of waterproofing, such as repairing operations of cracks or gaps in the outer wall of a residential building and repairing operations of a joint between a bathtub and a wall surface of a bathroom, by filling materials, such as a silicon type filling material, (hereinafter simply referred to as caulking materials).
2. Description of the Related Art
For example, a caulking material known as a silicon sealant is commercially available on the market in a form of a cartridge filled with a fixed amount of the material. The cartridge may be set in a dedicated caulking gun to be used for the filling operation.
In general, the caulking gun includes a lever in the form of a trigger that can be pulled by the user grasping a handle portion of the caulking gun to move an push rod, whereby the caulking material can be extruded from a nozzle of the cartridge. In the case of this completely manual type caulking gun, great fatigue is involved as a result of the repetition of the extruding operation. In view of this there has been provided an electric caulking gun using an electric motor as a drive source. Techniques related to this electric caulking gun are disclosed, for example, in JP-A-8-257465 (also published as Japanese Patent No. 3598565), JP-A-58-137465, and U.S. Pat. No. 4,615,469 (Also published as JP-A-59-222251). In the electric caulking guns as disclosed in these publications, the electric motor is started to move the push rod when a switch lever is operated to be turned on. Therefore, unlike the manual type caulking gun, in which the operation force of the lever generates the extrusion force, the user can easily perform the filling operation repeatedly.
However, the electric caulking guns potentially involve a problem of so-called after-dripping, in which some caulking material is discharged due to the residual pressure inside the cartridge immediately after the stopping of the electric motor. JP-A-8-257465 discloses a technique for inhibiting the problem of after-dripping. According to an after-dripping prevention mechanism disclosed in this publication, the electric motor is reversed immediately after the of operation, so that the push rod is forcibly restored to thereby release the residual pressure inside the cartridge, whereby it is possible to prevent after-dripping.
However, because the electric motor is reversed to forcibly restore the push rod in the case of this after-dripping prevention mechanism, a gap may be generated between the rear end surface of the cartridge (the surface to be pressed by the push rod) and the front end of the push rod. Thus, when the electric motor is started again, the push rod moves idle by an amount corresponding to this gap before being pressed against the rear end surface of the cartridge, with the result that there is generated a time lag (a delay) by an amount corresponding to this idle movement (i.e., corresponding to the gap).
Therefore, there has been a need in the art for a technique of inhibiting the after-dripping without causing a time lag in pressing a cartridge by a push rod.


Testosterone ester triglyceride formulations, optionally further including adducts. Methods of in-situ control of the manufacture or formation of such adducts are also described.

Testosterone is the primary male sex hormone and an anabolic steroid. In men, testosterone plays a key role in the development of male reproductive tissues such as the testis and prostate, and promotes secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. Testosterone enanthate is the heptanoic acid derived ester of testosterone, and thus a prodrug of testosterone. Testosterone enanthate is less polar than free testosterone, and affords a sustained in vivo delivery of testosterone upon parenteral administration, by being slowly absorbed from the lipid phase. Thus testosterone enanthate can be administered at longer time intervals, for example one to four weeks.


A computer includes a processor that is programmed to activate a vehicle exterior light, and measure a luminance in a predetermined region outside the vehicle based on vehicle camera data. The processor is programmed to determine whether the vehicle exterior light is operational based the measured luminance.

Vehicles typically have multiple exterior lights such as headlights, turn signals, brake lights, tail lights, etc. A vehicle exterior light may fail to operate, which may impair, e.g., during night time, vehicle driver visibility and/or vehicle sensor operation. To detect other vehicles and/or a vehicle driving lane, a vehicle camera and/or a vehicle driver may need operational exterior lights that illuminate an exterior of the vehicle, e.g., the driving lane. Detecting non-operating exterior lights may be a challenge, e.g., due to cost of diagnostics circuitry, lack of existing mechanism, etc., for exterior light outage detection.


This invention relates to a toothbrush which includes tufts of bristles which are fixed to and project from a head to define a substantially rectangular brush surface and a pair of resilient gum massage members which are located on opposite long sides of the brush surface with each massage member being at least as long as the brush surface occupied by three tufts of bristles but shorter than the surface and as wide as a tuft of bristles.

It is well known that a substantial proportion of dental disorders and particularly tooth loss are directly attributable to periodontal deterioration and disease. Periodontal problems can be reduced by physical massage of the periodontal tissue or gums surrounding teeth. The bristles of a conventional toothbrush provide the cleansing action of the brush by abrasion and picking and although they do come into contact with the user's gums the massage action they provide is minimal.
Brushes intended for gum massage are known. These brushes include rubber or like formations which are arranged amongst the conventional brush bristles for massaging the user's gums while the conventional bristles provide the normal abrasive cleaning and picking action. In one form of known brush the formations extend along the length of the bristle zone on either side of the brush head and in a second form are columns or cones made of rubber which are spaced among the bristles. A problem with brushes of the first type is that the formations prevent or at least seriously inhibit the conventional and necessary action of the brush bristles in cleaning the interstices between the teeth when the brush head is moved transversely over the length of the user's teeth. Additionally, these brushes are unacceptable from a hygienic point of view in that the spaces between the formations and the adjacent bristles on the brush head provide excellent traps, which are difficult to clean, for used toothpaste and particles dislodged from the user's teeth. A disadvantage to brushes of the second type is that the formations are of necessity made from soft resilient material to avoid point contact damage to the user's gums and because of the flexibility over their lengths and their small gum contact areas provide insufficient traction on the gums, particularly in the longitudinal direction of the brush head, to be effective in providing the required massage action without damage to the user's gums.


A machine is provided for molding an optical element by using a molding block having upper and lower molding dies, a sleeve die and a glass blank combined integrally with each other. The machine includes a chamber which accommodates a heating zone having a plurality of sections for heating the molding block from above and below, a deformation zone for pressing the molding dies and a cooling zone having a plurality of sections for cooling the molding block. The chamber is formed with an inlet and an outlet for the molding block. The sections of the heating zone, the deformation zone and the sections of the cooling zone are provided independently of one another. A transport member is provided for sequentially transporting the molding block through the heating zone, the deformation zone and the cooling zone, and first and second shutters are provided for opening gas supply member is provided for introducing nonoxidizing gas into the chamber.

The present invention relates to a molding machine for mainly press molding a high precision optical element and a method of producing the optical element by using the molding machine.
Recently, in production of an optical element represented by an optical lens, a number of attempts have been made in which the optical element is obtained by press molding through cancellation of a polishing process. Thus, at present, press molding of the optical element is used for mass production by several optical lens makers. In the most efficient of the known methods for press molding optical elements, molten glass material is poured into a die and then, is press molded. However, in this known method, it is difficult to accurately control contraction of glass during cooling of glass and thus, a high precision optical element cannot be produced efficiently. This is because the temperature difference between the melting point of about 1,300.degree. C. at which glass is molten and the transition point at which glass is set is too large. Therefore, an extremely large period is required for cooling glass. Thus, even if a high precision optical element is obtained, this known method is problematical in view of its efficiency. Accordingly, in a general known molding method, a glass blank is preliminarily worked into a certain shape and then, is supplied between molding dies so as to be press molded through heating as described in, for example, Japanese Patent Laid-Open Publication Nos. 58-84134 (1983) and 60-200833 (1985).
Japanese Patent Laid-Open No. 61-26528 (1986) discloses a machine for pressing a lens, which is constituted by an inlet chamber for a glass preform, a heating chamber, a pressing chamber, a gradual cooling chamber and an outlet chamber for the lens. In this known machine, the machine housing as a whole should be adapted to be evacuated to vacuum and a number of molding dies are employed so as to raise production rate. However, this known machine is quire expensive because the machine housing as a whole should be evacuated to vacuum. Furthermore, since a number of the molding dies machined with high precision are employed, production cost of the lens rises considerably.
Meanwhile, Japanese Patent Laid-Open Publication No. 62-292629 (1987) discloses a machine in which processes of heating, pressing and cooling molding dies can be performed in an identical chamber and the molding dies are heated efficiently from above and below. However, productivity of this prior art machine is low due to its intermittent transport of the molding dies. Furthermore, this prior art machine has a drawback that a large uniform heating portion of a heat source cannot be obtained.
Japanese Patent Laid-Open Publication Nos. 62-292636 (1987) and 2-34526 (1990) discloses a machine in molding dies are heated and cooled from one side. Thus, the conventional machine has such problems that the molding dies cannot be heated and cooled efficiently and that since a temperature difference occurs in a vertical direction of the molding dies, lenses having stable performance cannot be obtained.
Furthermore, U.S. Pat. No. 4,913,718 discloses a machine in which a glass blank and molding dies are separately heated on an identical pallet and the glass blank in a high-temperature state is supplied into the molding dies so as to be press molded. However, this known machine is necessarily structurally complicated and expensive due to the need for it to handle glass blanks at high temperatures, etc.
As is seen from the foregoing, the prior art documents do not give detailed descriptions of temperature distribution and uniform heating of the glass blank, the molding dies, the heat source, etc., on which performance of the molded item directly relies.

Matsushita Electric Industrial Co., Ltd.


A holder for a cutting tool includes a body having a first channel for receiving a stem portion of the cutting tool. The body has a second channel intersecting with the first channel. The holder further includes a plunger to be inserted in the second channel, the plunger having a third channel the cross section of which at least partly overlaps with the cross section of the first channel when the plunger is inserted into the body so as to enable the stem of the cutting tool to extend into the third channel when the stem is inserted in the first channel. The holder further includes a mechanism for locking the stem against movement relative to the body by means of the plunger. A cutting tool for use in such a holder and a cutting insert are also provided.

The invention relates to a holder for a cutting tool. In particular the invention relates to holder for a cutting tool where the holder is adapted to firmly hold the cutting tool to transfer a rotational movement from a driving source in boring or milling machine to a cutting tool secured in the holder. The cutting tool may preferably be designed for chip forming metal cutting.
Precision cutting requires that the position at which a cutting tool is located when held by a holder for the cutting tool is highly reproducible. For this purpose various types of holder for cutting tools are known. Precision hole making is defined by characteristics—among others—such as straightness, roundness and position accuracy, and in addition—for some applications—the properties of the produced surfaces. In particular for high integrity components such as gas turbine rotors and pressurized vessels a high demand is imposed on the tools in order to achieve the desired property on the machined surfaces. The type of tool holder used has an impact of the quality of the worked surfaces.
A common type of tool holder is designed as body having a channel for receiving a stem portion of a cutting tool. The stem portion will be locked by screws that penetrate into the channel in order to engage with the stem portion of the cutting tool. With this type of locking engagement, load is concentrated to one or two locations where the screw or screws engage with the stem. It has shown that this type of engagement does not suppress oscillations for certain frequencies, which frequencies depend on the location of the connection between the screw and the shaft. Another type of locking device is presented in U.S. Pat. No. 6,568,055, where an axially wedge shaped sleeve is pushed by a hydraulic actuator to tighten a boring arbour.
It is desirable to provide a tool holder that facilitates preparation of high quality surfaces and which creates conditions for a cost-efficient production and/or use of the tool holder.
A tool holder according to an aspect of the invention comprises a body having a first channel for receiving a stem of the cutting tool. The body furthermore includes a second channel intersecting with the first channel. A plunger is inserted in the second channel. The plunger has a third channel with a cross section which at least partly overlaps with the cross section of the first channel when the plunger is inserted into the body. The stem of the cutting tool thereby extends into the third channel when the stem is inserted in the first channel. The holder further comprises a mechanism for locking the stem against movement relative to the body by means of the plunger. An aspect of the invention is based on the observation that the quality of the machined surfaces is dependent on the wear of the cutting insert. By virtue of the fact that the holder comprises a plunger with said third channel, which plunger is configured for acting on the stem, an accurate holding of the cutting tool can be achieved. Further, by arranging the plunger moveable in the second channel which intersects with the first channel into which a cutting tool is inserted, lateral compensation of the position of the cutting tool is facilitated. Hence, production of high quality surfaces is facilitated.
According to an embodiment, the plunger comprises said locking mechanism. In this way, the need for including functional features for locking the cutting tool in the body is eliminated. It is therefore easier to make the body sufficiently sturdy to achieve a desired stiffness of the tool holder. Preferably the body may be formed as a monolith only provided with ducts for cooling liquid and means for locking and positioning of the plunger relatively to the body. Hence the tool holder enables production of high quality surfaces by facilitating lateral positioning of the cutting tool, while allowing a compact stiff design of the body. The plunger may thus be moveably arranged in the second channel so as to allow lateral dislocation of the plunger and hence of the cutting tool. Accurate lateral positioning of the cutting insert to compensate for the successive wear of the cutting insert may therefore be achieved in a straightforward manner while maintaining a firm grip of the cutting tool.
According to a further embodiment, said locking mechanism comprises a membrane delimiting a pressure chamber. The holder may comprise a mechanism for pressurizing the pressure chamber in order to lock the stem against movement relative to the body. In this embodiment a holder is provided, which enables suppression of oscillation over a wide range of frequencies.
According to a further embodiment, the membrane forms a part of the third channel and is configured to act directly on the stem. The pressure mechanism is configured to press the membrane directly against the stem. Thus, the membrane is integrated into the plunger, which creates further conditions for a firm locking of the cutting tool.
The contact between the stem and the membrane forming part of the third channel in the plunger ensures a distribution of the load on the stem enabling suppressions of oscillation of the cutting tool.
Optionally, the part of the third channel which is formed by the membrane is cylindrical and especially circular-cylindrical. The use of a cylindrical membrane ensures that the membrane grips the stem with a constant radial load. A hydraulic oil pipe is connected to the pressure chamber for enabling a movement of the membrane thereby enabling locking or release of the stem of the cutting tool. The use of hydraulic locking of the stem has a beneficial effect on the suppression of oscillations of the cutting tool.
Optionally a hydraulic oil pipe connects the pressure chamber with an outwardly facing end wall of the plunger, at which the mechanism for pressurizing the pressure chamber is located.
Optionally the first channel may extend along a first length axis and the second channel may extend along a second length axis. Each of the first and second channels are preferably straight. Optionally the first and second axes are essentially perpendicular to each other. By arranging the first and second axes perpendicular to each other, the risk of that the stem is axially dislocated during the locking process is reduced since a small movement of the plunger in the second channel in this case will not result in a translation of the plunger relatively to the length axis of the first channel. Hence movement of the plunger will not result in axial dislocation of the cutting tool.
Optionally the third channel extends through said plunger so as to enable a stem of a cutting tool to extend through said third channel when the stem is inserted in the first channel. The third channel is preferably straight. By allowing the stem to pass through the third channel a good contact between the stem and the membrane is ascertained.
Optionally the holder includes a mechanism for movement of the plunger along a length axis of said second channel so as to position the stem in a lateral position relatively to the body. Lateral positioning is performed to enable accurate positioning as the cutting insert wears out during use.
Optionally the holder comprises means for angular and/or axial positioning of the cutting tool relative to the body. Preferably, the positioning means comprises an indentation provided at an opening of the first channel, which indentation is arranged to receive a notch provided on said stem of the cutting tool, thereby enabling axial and angular positioning of the cutting tool.
The invention furthermore relates, according to an aspect thereof, to a cutting tool for use in a holder, which cutting tool includes a stem. The cutting tool comprises means for angular and/or axial positioning of the cutting tool relative to a body of the holder. Particularly said positioning means comprises a notch provided on a stem of the cutting tool, thereby enabling axial and angular positioning of the cutting tool in the holder. The notch is to be inserted in a corresponding indentation made at the holder for enabling axial and angular positioning of the tool in the holder.
Optionally the stem portion of the cutting tool includes a cooling liquid flow entrance in a lower region of the stem, a cooling liquid feeding conduit extending from said liquid flow entrance to a head located on the top of said stem, and a cooling liquid ejector outlet nozzle connected to said cooling liquid feeding conduit at said top portion of said stem.
Optionally the cooling liquid ejector outlet nozzle has a smaller cross sectional area than said cooling liquid feeding conduit. By arranging the cooling liquid feeding conduit with a larger cross sectional area than the cooling liquid ejector outlet nozzle it is ensured that the pressure drop in the cutting tool can be reduced.
Optionally the cooling liquid ejector outlet nozzle has a length between 1 mm and 3 mm. By making the cooling liquid ejector outlet nozzle short an output spray from the nozzle will be focussed. Long narrow channels will tend to result in a distributed spray. By making the length of the narrow cooling liquid ejector outlet nozzle short, the spray will thus be focused.
Optionally the cooling liquid feeding conduit is eccentric in relation to a centre axis of said stem. Steep changes in flow direction result in cavitation losses. The eccentric location allows for less steep change in flow direction in the vicinity of the cooling liquid ejector outlet nozzle.
The cutting tool preferably comprises a head located on the top of the stem. Optionally, said head includes a first surface, which extends in a plane in parallel with a longitudinal axis of the cutting tool, wherein a cutting insert is located on the first surface, and a second surface which extends in a plane which is inclined with regard to a plane at right angles to the longitudinal axis and which intersects with a length axis of the cooling liquid ejector outlet nozzle. This arrangement allows that the cooling liquid ejector outlet nozzle, which may have an exit opening in the inclined surface which extends perpendicularly to the direction of the inclined surface, may focus a cooling liquid jet on an edge of a cutting insert. The location of the rim an exit opening in a plane vertical to the length axis of the cooling liquid ejector outlet nozzle reduces spray diffusion in comparison to when the plane is inclined in relation to the length axis of the cooling liquid ejector outlet nozzle.
Optionally the cutting tool includes a cutting insert which before use has a polygonal cross sectional shape, that sides of the polygon meet at rounded corners and that a straight portion is present in the rounded area. Preferably, the polygon has the shape of an equilateral triangle or a square. Optionally the cutting insert is secured to said head such that said straight portion is coaxial with a centre axis of a stem of said cutting tool. By allowing the straight portion to be coaxial with the centre axis a reduction of wear of the cutting insert and of unintended deformation of the worked goods can be obtained. It is believed that in the event no straight portion is present in the rounded area a local concentration of force is obtained at the contact between the goods and the cutting insert such that the contact force will initially be too high with excessive wear and risk for damage of the cutting insert as well as of the worked goods as a consequence.
The invention also relates, according to an aspect thereof, to a cutting insert which before use has the shape of an equilateral triangle or a square, which sides meet at rounded corners and that a straight portion is present in the rounded area. Optionally, the rounded corners have a curvature radius between 0.6 and 1.2 mm and that the straight area has a length between 0.07 and 0.15 mm.

Holder for a cutting tool, a cutting tool and a cutting insert


An x-ray tube of a CT scanner is powered by a high-voltage power supply (26). The high-voltage power supply includes a plurality of sections (102) each having three straight-up transformers (48) which receive three 120.degree. phase shifted alternating current components as inputs. The straight-up transformers perform a direct voltage transformation with single or multiple transformers and with no capacitive multipliers. Each straight-up transformer has a primary winding (T1) and two secondary windings (T1-A, T1-B). The secondary windings are connected together in delta and wye configurations (84). The alternating current components have their voltage boosted and are rectified and summed to form a high-voltage output that is substantially ripple-free. A pulse-width modulated converter (34) generates a conditioned output current from an inputted direct current. Resonant inverters (36) receive the conditioned output current and convert the conditioned, direct current into alternating current received by each of the straight-up transformers (48) in the stack. The resonant inverters (36) operate at or near resonance. The power supply (26) has no added capacitance and stores a minimum of energy. It provides rise and fall times which enable the x-ray tube to perform sub-second exposures with very short rise and fall times.

The present invention pertains to the art of high-voltage power supplies. It finds particular application in conjunction with high power generators for CT scanners and will be described with particular reference thereto. However, it is to be appreciated, that the present invention will also find application in conjunction with high-voltage supplies for other purposes.
Early x-ray tubes were provided with oil-filled transformers for providing an unregulated, alternating current source of high-voltage power. The tube itself acted as a rectifier, emitting radiation on alternating half cycles when the anode was positive and the cathode was negative. Subsequently, diode rectifier tubes, filter capacitors, and controlled grid tubes were added to deliver smoother and more stable power, improving image quality and repeatability. By operating at a 60 Hz power line frequency, these x-ray generators were characterized by their large size, heavy weight, and high stored energy. They were also reliable, had a low cost, were well understood, and were relatively simple to manufacture. Of course, they suffered from significant 60 Hz x-ray output fluctuations.
Another type of power supply developed for commercial use was a solid-state switching-type high-voltage power supply. These power supplies incorporated a kilohertz range inverter which reduced the size and weight of an HV transformer and output filter. Kilohertz range ripple had serious detrimental effects, particularly in sensitive x-ray equipment like CT scanners which measure x-ray variation at the detectors with high sampling rates to generate a diagnostic image. To smooth the ripple, capacitors were added at the output. The capacitors stored energy which slowed switching response and contributed to arcing problems. The capacitance emptied its stored energy into the short circuit caused by the arcing increasing anode and other tube damage. These switching power supply generators were also plagued by numerous problems due to their complexity and dependence on SCR inverters, infamous for their commutation failures.
Individual transformers commonly were used to boost line voltage to a few thousand volts. Stacked voltage multipliers, for example, were used to increase the voltage to the +75,000 and -75,000 volt levels commonly applied across today's x-ray tubes. Pairs of diodes or diode bridges or half bridges were connected by capacitors. The current pulses built voltages on the capacitors. A sufficiently large number of diodes and capacitors were connected in series that the voltage at the end had built to about 75,000 volts.
In a cascade arrangement, each transformer had a capacitance connected across its output to act as a voltage source at the voltage level of the transformer output. A sufficient number of the capacitors were connected in series to build the voltage to 75,000 volts or other selected voltage level. The stack of capacitors stored a large amount of energy.
The present invention provides a new and improved high-voltage power supply particularly adapted for x-ray tubes which overcome the above-referenced problems and others.

High-voltage power supply for x-ray tubes


A flexible carrier tape for storage and delivery of components by an advancement mechanism, comprises a strip portion, a plurality of aligned pockets spaced along the strip portion for carrying the components, wherein each pocket includes a bottom wall, and a non-pressure sensitive adhesive comprising a thermoplastic elastomer block copolymer on the bottom wall of the pocket for retaining a component in the pocket.

1. Technical Field
This invention relates generally to carrier tapes of the kind used to transport components from a component manufacturer to a different manufacturer that assembles the components into new products. More specifically, this invention relates to carrier tapes for storing electronic surface mount components and for supplying those components seriatim to a machine.
2. Description of the Related Art
In general, carrier tapes that are used to transport components from a component manufacturer to a different manufacturer that assembles the components into new products are well known. For example, in the field of electronic circuit assembly, electronic components are often carried from a supply of such components to a specific location on a circuit board for attachment thereto. The components may be of several different types, including surface mount components. Particular examples include memory chips, integrated circuit chips, resistors, connectors, dual in-line processors, capacitors, gate arrays, etc. Such components are typically affixed to a circuit board that may later be incorporated into an electronic device.
Rather than manually affixing each individual electronic component to a circuit board, the electronics industry makes extensive use of robotic placement machines, sometimes known as "pick-and-place" machines, which grasp a component at a specific location (the supply) and place it at another specific location (the circuit board). To ensure the sustained operation of the robotic placement machine, a continuous supply of electronic components must be furnished to the machine at a predetermined rate and location to permit the machine to be programmed to repeat a precise sequence of movements during every cycle. It is therefore important that each such component be located in the same position (i.e. the point at which the robotic placement machine grasps the component) as each preceding and succeeding component.
One way to provide a continuous supply of electronic components to a desired location is to use a carrier tape. Conventional carrier tapes generally comprise an elongated strip that has a series of identical pockets formed at predetermined, uniformly spaced intervals along the length of the tape. The pockets are designed to receive an electronic component. A continuous cover tape is applied over the elongated strip to retain the components in the pockets. The tapes also normally include a series of through holes uniformly spaced along one or both edges of the elongated strip. The through holes receive the teeth of a drive sprocket that advances the tape toward the robotic placement machine.
Each pocket is shaped to closely receive the electronic component. Frequently, the pockets are sized to match a particular component. In fact, the tolerances between the component and the pocket walls may be quite small such that a given carrier tape may only be useful with a single size of component. Thus, a component of a different size would require a new pocket design. In conventional carrier tapes, if the pockets are not properly sized for the stored component, the component may rotate within the pocket making subsequent removal by automatic pick-up equipment difficult or impossible since these devices require precise component orientation for proper removal. A component may even turn over within its pocket during shipping, necessitating reorientation of the stored component. Excessive component movement may also result in a component becoming damaged as it collides with the pocket walls. Given these variables, it can be expensive to design, manufacture and store a multitude of different carrier tapes having different pocket designs for different components.
Eventually, the carrier tape is fed to a robotic placement machine that strips the continuous cover tape from the carrier and removes the components from the pockets and places them onto the circuit board. Removal of the component is commonly accomplished with a vacuum pick-up device that grasps the top of the component by suction. The vacuum pick-up may be assisted by a push-up needle or probe that penetrates a hole formed in the floor of the pocket to push up against the component. The removed cover tape is waste that must be gathered and disposed.
U.S. Pat. No. 4,778,326 (Althouse et at.) discloses a carrier that is adapted for handling semiconductor chips and other smooth-surfaced articles. The carrier includes a base that has a recess within its interior. The recess includes a plurality of protuberances that support a thin flexible film cover that overlies the base. Semiconductor chips are carded on the upper surface of the cover. By connecting the base to a vacuum, the cover can be drawn down into the base recess and against the protrusions. This converts the cover from a flat condition in full surface contact with the semiconductor chip to a wavy or undulating condition having reduced surface contact with the semiconductor chip. Reportedly, the reduced surface area contact facilitates removal of the semiconductor chip.
However, Althouse et al. note that while their invention is adapted for use with a wide variety of chip sizes, the number and the size of the protuberances employed in the base are selected in relationship to the size of the chips to be handled. As a result, a chip which is too small for proper use with the carrier could be drawn down with the cover into a recess and its removal from the carrier would not be facilitated.
U.S. Pat. No. 4,667,944 (Althouse) discloses a related device in which a textured fabric is sandwiched between the cover and the base. To facilitate removing the semiconductor chip from the cover, surface contact between the cover and the chip is reduced by drawing portions of the cover into crevices in the upper face of the textured fabric by applying a vacuum thereto.
Although the invention is apparently adapted for use with a wide variety of chip sizes, Althouse notes that among the factors to be considered in selecting the textured fabric is the size of the devices to be handled.
U.S. Pat. No. 5,089,314 (Masujima et al.) discloses a carrier tape for surface mounted electronic circuit elements which includes a tape body having an adhesive applied thereto. The adhesive is formed of a material that does not exhibit any adhesion at a normal temperature but which does exhibit adhesion when heated to a temperature of about 80.degree. C. The adhesive may be a silicone, an acrylic resin, or a mixture of silicone and acrylic resin. When the electronic circuit element is removed from the carrier, the adhesive transfers to the bottom of the circuit element. The circuit element and the adhesive are then heated such that the adhesive can provisionally bond the circuit element to a printed circuit board.
U.S. Pat. No. 4,966,281 to Kawanishi et al. discloses an electronic component carrier having a series of electronic component-mounting portions that include a layer of adhesive. The adhesive is a rubber type, an acryl type or a silicone type having suitable pressure sensitive adhesive properties. The use of a push bar enables smooth removal of the electronic component from the adhesive layer.
However, there is still a need for a carrier tape that can securely retain a stored component in the proper orientation for subsequent removal by an automated device. It would be highly desirable if this could be accomplished without the need for separate carrier tapes for different component sizes and designs. It would also be highly desirable if this could be accomplished without using a cover tape. Such carrier tapes would offer even further advantages if any adhesive used to retain the components on the carrier tape did not display pressure sensitive adhesive properties because tacky pressure sensitive adhesives can retain dirt and other potential contaminants. Similarly, it would be useful if the adhesive did not transfer to the stored component upon removal of the component so as to reduce the risk of contamination.


A worm and meshing worm gear are provided. The worm has a central cylindrical portion, and tapered portions at either end thereof. The angle of taper of the two tapered portions is the same, but in different directions. The angle of taper is substantially equal to 360 degrees divided by the number of teeth in the worm gear. Contact between the worm and gear occurs over three times the number of teeth in which contact is obtained with a conventional cylindrical worm. The worm is capable of being formed by thread rolling.

Worm gearing is well known and is used in installations where a driving shaft and a driven shaft must be at right angles to one another. The worm is of cylindrical outline in simplest form and has one or more thread turns or spiral teeth thereon. A meshing worm gear has a plurality of appropriately twisted teeth having tooth flank surfaces, generally of an involute curved shape, which are conjugate to the worm.
The instantaneous contact between a worm and a worm gear is at a rather limited area where the worm is tangent to the gear. The area of contact is quite limited, generally being aong a full line on one tooth and a very short line on an adjacent tooth. Consequently, only a limited amount of power can be transmitted between a worm and worm gear.
Efforts have been made to provide greater contact between a worm and a worm gear and thereby to permit greater transmission of power by shaping the worm somewhat in the nature of an hourglass. Manufacture of such worms is quite a complicated process, requiring precise control of the relative positions of the worm blank and of a cutting tool as the worm blank is turned. It is not possible to form hourglass worms by a thread rolling process as is possible with straight worms.


An apparatus configured to facilitate mounting a first device to a second device where the first device has a plurality of first apertures and the second device has a plurality of second apertures. The apparatus includes a base member and a plurality of post members affixed to the base member at a plurality of attachment loci. Each post member is substantially in register with a first aperture and with a second aperture when the first device, the second device, and the apparatus are in a mounting orientation. Each post member includes a tab member and a mounting aperture which traverses the post member. For each post member and for each first aperture, the tab member is configured to flex from an initial position to pass through the first aperture when the post member is urged into the first aperture. The tab member returns to the initial position when the post member passes a predetermined distance into the first aperture to captively retain the first device intermediate the tab member and the base member. Each first aperture is substantially coaxial with one of the second apertures and substantially coaxial with one of the mounting apertures when in the mounting orientation.

The present invention is generally related to an apparatus for mounting a subunit to a host unit in assembling a device. More particularly, the present invention relates to a mounting apparatus to facilitate mounting a first device to a second device. The mounting apparatus snap-engages one of the devices and provides mounting apertures for through-fastener mounting of the first device to the second device with the snap-engaged mounting apparatus intermediate the first device and the second device.
Snap-engaging structures are found in various environments. For example, U.S. Pat. No. 4,841,100, of Jun. 20, 1989, to Ignasiak for "Expanding Surface Mount Compatible Retainer Post", discloses an expandable retainer post for use with printed circuit boards employing surface mount technology intended to be attached to a host board. The Ignasiak device, however, does not provide a mounting aperture through his snap-engaging structure to facilitate mounting with a through-hole fastener.
U.S. Pat. No. 5,365,408, of Nov. 15, 1994, to Apitz for "Chassis with a Movable Attachment Element Affixed Thereto", discloses a chassis with attachment elements which cannot be separated from the chassis, with an attaching device for carrying and attaching components or chassis elements. In one embodiment, Apitz discloses a column-shaped attachment element for attaching a plate-shaped component using a hot-molded retaining head. If the retaining head must be removed during servicing, or if it breaks off, a self-tapping screw may be screwed into a central bore in the column-shaped attachment element as a repair element to affix the subchassis to the original chassis in the same manner as the original retaining head. However, Apitz does not disclose employment of a snap-engaging apparatus with a through-aperture to facilitate mounting a subassembly to a host assembly.
Another known method of attaching a printed circuit board to a host device is to heat stake a mounting plate to the printed circuit board to provide the requisite stand-off spacing between the printed circuit board and the host device.
There is a need for an inexpensive and reliable apparatus to facilitate mounting a first device, such as a printed circuit board, to a second device in a manner facilitating mounting by a through-hole fastener. It is particularly desirable that such a mounting apparatus be configured to provide a predetermined stand-off distance between the first device and the host device.

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A process for synthesizing nanosized powders utilizes a hybrid exploding wire device containing a solid metal wire fuse in the bore of a tube that is open at each end. The ends of the fuse are connected to electrodes on the ends of the tube. The electrodes are designed to erode to maintain a heavy metal plasma. The bore may comprise a corresponding ceramic to be produced, and a microcrystalline powder of a corresponding ceramic may be retained within the bore. An electrical discharge vaporizes and ionizes the fuse. The tube confines the radial expansion of the plasma such that the plasma exits from both ends of the tube where it reacts with a suitable gas to form nanoscale particles. In addition, the plasma gas ablates and vaporizes a portion of the bore wall to contribute to the nanoceramic synthesis. Other alternatives include replacing the fuse with a thin conductive sheath or a consumable metal insert.

1. Field of the Invention
The present invention generally relates to a method and system for the production of submicron materials, and in particular to a method and system of synthesizing, in bulk quantities, nanosized powders, including nanocrystalline ceramics. Even more particularly, the present invention relates to a method and system for increasing the rate and thereby reducing the cost of the production of bulk quantities of nanosized powders by electrothermal gun synthesis.
2. Description of Related Art
Ceramic materials are used in a wide variety of applications, and generally have excellent heat resistance, corrosion resistance, and abrasion resistance, as well as unique electrical and optical properties. Ceramic material, as used herein, generally refers to an oxide, nitride, boride or carbide of a metal, or a mixture thereof. Very fine ceramic powders are used in a large number of industrial processes to introduce or modify material properties. These materials can pose difficulties in sintering but, when they are converted to ultrafine particles, particularly submicron crystalline particles, numerous traditional problems are avoided. Accordingly, several processes have been devised for fabricating ultrafine, or submicron, crystalline materials, such as those of 1-500 nanometer size, referred to herein as xe2x80x9cnanosized,xe2x80x9d xe2x80x9cnanocrystalline,xe2x80x9d xe2x80x9cnanoparticles,xe2x80x9d and the like.
Techniques for producing nanocrystalline materials generally fall into one of three categories, namely, mechanical processing, chemical processing, or physical (thermal) processing. In mechanical processes, fine powders are commonly made from large particles using crushing techniques such as a high-speed ball mill. There are several disadvantages with this approach.
Sometimes metallic powders and highly reactive metals are combined with and subjected to such milling, which can pollute the material with a nanocrystalline alloy. Fragmented powders produced by mechanical processes can also result in particles of inconsistent shapes and sizes, and are often coarse and so not suited for high-performance applications.
With chemical processes, nanocrystalline materials are created from a reaction that precipitates particles of varying sizes and shapes, using a family of materials known as organometallics (substances containing combinations of carbon and metals bonded together). It is difficult, however, to produce ultrafine ceramics using organometallics without introducing excess carbon, or nitrogen (or both) into the final composition. Solution-gelation (sol-gel) ceramic production is similar to organometallic processes, but sol-gel materials may be either organic or inorganic. Both approaches involve a high cost of raw materials and capital equipment, limiting their commercial acceptance.
One of the earliest forms of physical, or thermal, processing, involves the formation and collection of nanoparticles through the rapid cooling of a supersaturated vapor (gas phase condensation). See, e.g., U.S. Pat. No. 5,128,081. In that example, a raw metallic material is evaporated into a chamber and raised to very high temperatures, and then oxygen is rapidly introduced. See also U.S. Pat. No. 5,851,507, in which a carrier medium is mixed with precursor material which is vaporized and subsequently rapidly quenched.
Thermal processes create the supersaturated vapor in a variety of ways, including laser ablation, plasma torch synthesis, combustion flame, exploding wires, spark erosion, electron beam evaporation, sputtering (ion collision). In laser ablation, a high-energy pulsed laser is focused on a target containing the material to be processed. The high temperature of the resulting plasma (greater than 10,000xc2x0 K.) vaporizes the material so quickly that the rest of the source (any carrier and quenching gases) can operate at room temperature. The process is capable of producing a variety of nanocrystalline ceramic powders on the laboratory scale, but it has the great disadvantage of being extremely expensive due to the inherent energy inefficiency of lasers, and so it not available on an industrial scale.
The use of combustion flame and plasma torch to synthesize ceramic powders has advanced more toward commercialization. In processes, the precursor material can be a solid, liquid or gas prior to injection into the flame or torch, under ambient pressure conditions (the most common precursor state is a solid material). The primary difference between the two processes is that the combustion flame involves the use of an oxidizing or reducing atmosphere, while the plasma torch uses an inert gas atmosphere. Each of these processes requires relatively expensive precursor chemicals, such as TiCl4 for the production of TiO2 by the flame process, or TiC and TiB2 by the plasma process. A feature of both methods is the highly agglomerated state of the as-synthesized nanocrystalline ceramic powders. While for many applications the agglomeration of the powders is of little significance, there are situations where it is a shortcoming. Loosely agglomerated nanoparticle powders are produced in the combustion flame method of U.S. Pat. No. 5,876,683.
In the plasma process, reactants or feed materials are delivered to a plasma jet produced by a plasma torch. See generally, U.S. Pat. Nos. 4,642,207 and 5,486,675. Alternatively, the feed material may be delivered to the plasma stream by arc vaporization of the anode. The anode is normally metallic but may be a metal-ceramic composite. An improved plasma torch process is described in U.S. Pat. No. 5,514,349. That process can produce non-agglomerated ceramic nanocrystalline powders starting from metalorganic precursors, and uses rapid thermal decomposition of a precursor/carrier gas stream in a hot tubular reactor combined with rapid condensation of the product particle species on a cold substrate. Plasma torch processes, while gaining some limited commercial acceptance, are still energy inefficient and often involve materials which are extraneous to the products being produced. For example, in the ""349 patent, a working gas must be heated by the plasma arc, which is wasted energy. Also, since the product particles are suspended in the hot process gas stream, it is necessary to quench not just the particles but the process stream as well. The multiple gases used (the reaction gas, quench gas, and passivating gas) are either wasted, or must be separated for reuse.
Another apparatus for producing nanosized particles is the exploding wire device. A conventional exploding wire device is illustrated in FIG. 5. A pulsed current discharge is driven through a small diameter wire that is typically on the order of 0.1 mm. The resulting joule heating of the wire vaporizes and ionizes the wire resulting in plasma which expands radially. The nearly cylindrical plasma contact surface which expands into the ambient gas, undergoes a reaction with the gas and subsequently cools. The mixing process relies on molecular diffusion and the cooling process is nearly isentropic. Production rates are typically only a few milligrams owning to the small diameter wire necessary for complete vaporization.
Another device that builds on the exploding wire method is a conventional capillary plasma device, shown in FIG. 6. Conventional capillary plasma devices produce hydrocarbon-based plasmas that are used to ignite explosives because the plasma will not negatively react with the explosive. The capillary plasma device consists of two non-eroding electrodes positioned at the ends of a non-conducting bore with one open end. A fuse wire is connected between the electrodes. The process begins with an electrical discharge that explosively vaporizes and ionizes the fuse wire between the two electrodes. The discharge is maintained by the erosion and subsequent ionization of the liner to produce a dense plasma inside the bore which then exits from the open end of the device. The sealed end or breech of the gun must be capable of withstanding extremely high pressures in the order of 10,000 psi. The plasma exits the gun and is then used to ignite the explosive. The length to diameter ratio of bore, L/D, is large which helps to promote bore wall erosion to sustain the discharge. This process is not well suited for ceramic production because the erosion of a ceramic bore would not produce the ionization needed to sustain the plasma and consequently the production would be low.
The electrothermal gun, also known as an electrogun or capillary discharge device (shown in FIG. 7), is a pulsed power device for the production of very high velocity plasma jets and vapors of different metals such as aluminum or titanium. A pulsed, high current arc is struck down the barrel of a gun, between an electrode in the breech of the gun and an electrode at the muzzle. This arc produces rapid vaporization of the electrodes and of the barrel of the gun so that a pulsed, high-temperature, high-velocity plasma jet is fired out the muzzle.
Electrothermal guns are superficially similar to plasma torches. In a plasma torch, an electric arc is used to convert a gas stream into a plasma jet. Electrothermal guns have been used for a variety of applications such as laboratory plasma producers, spacecraft thrusters, propellant ignitors for high performance guns, and plasma armature sources for electromagnetic rail guns. Electrothermal guns also have been used to vaporize and project an initially liquid gas (such as argon) to atomize an external stream of molten metal. In addition, electrothermal guns have been used to heat and propel powdered material for the application of coatings. xe2x80x9cElectrothermal gun synthesisxe2x80x9d is the use of an electrothermal gun to synthesize nanomaterials such as powdered material with particle sizes of approximately 100 nanometers or less. The plasma jet itself is converted physically or physically and chemically into ultra-fine powder. The material composing the plasma jet typically comes from the breech electrode or the muzzle electrode.
In operation, it is frequently necessary to change the breech electrode of the gun. For production of bulk quantities, it is an economic necessity to accomplish this change automatically rather than manually. Thus, simplification of the breech electrode replacement process produces significant cost reduction. For proper operation, the breech electrode must form an effective seal against the reverse flow of high-pressure plasma. The breech electrode is installed with a high-force mechanical preload to insure that the seal remains effective against the sudden onset of high-pressure plasma. In addition, a heavy-duty electrical connection to the breech electrode must be effected. A final consideration is that when the breech electrode is changed, the stub end of the breech electrode is wasted. A method and system for increasing the production rate and reducing the cost of the production of bulk quantities of nanosized powders by electrothermal gun synthesis is needed to overcome these limitations.
The limitations of the prior art are overcome by a new process for the synthesizing nanosized powders. The process utilizes a xe2x80x9chybrid exploding wirexe2x80x9d (HEW) device containing a small diameter solid metal fuse wire or foil sheath inside a cylindrical tube. The ends of the fuse are connected to electrodes which are designed to have sufficient erosion to maintain the heavy metal plasma. The cylindrical tube is designed to contain the large pressures generated when the plasma is produced. The bore may be made of but is not limited to the corresponding ceramics to be produced. Microcrystalline powder of corresponding ceramic may also be retained within the bore.
The process is initiated with an electrical discharge that vaporizes and ionizes the fuse. The tube confines the radial expansion of the plasma which forces it to exit from both ends of the tube where it mixes and reacts with a suitable gas to form nanoscale particles. In addition, the plasma gas will ablate and vaporize the bore wall contributing to the nanoceramic synthesis.
The benefits of the current invention are both chemical, via reaction of the metal vapor with the reaction gas, and physical via ablation of the bore wall, conversion processes are employed to produce the nanocrystalline ceramics. Having the plasma exit both ends of the bore eliminates the problems associated with high pressure breech seals and eliminates the corresponding forces because the internal pressures are used to balance each other. The dual bore also allows increased production by simultaneously operating two guns.
In an alternate embodiment, the fuse wire is replaced with a thin conductive sheath. The conductive sheath fits inside the bore which has been undercut to form an annular area. The annular area is filled with micron sized particles of the desired compound, reactant metal, or combination thereof. The process is initiated as described earlier and the conductive sheath is instantly vaporized. The micron particles are exposed to the plasma where they are vaporized and ejected with the plasma. The plasma jet with the ceramic vapor is rapidly cooled and nanosized particles are formed. The large surface area to volume ratio of the microparticle material overcomes the problems with low production rates by allowing quick and efficient conversions to nanoparticle ceramics.
In another embodiment, a consumable metal insert is placed in the center of the bore. In this version, a spark progresses from one electrode to the metal insert, and then from the insert to the other electrode. The metal insert is eroded and/or vaporized to sustain the discharge and increase production of the nanosized material. The external electrodes can be made of tungsten in an effort to minimize erosion so that they do not have to be replaced. Because the metal insert is in the center, the forces on it are symmetrical and they will balance one another. This eliminates the need for high pressure seals. In addition, there is no electrical contact on the metal insert so that it can be replaced quickly and easily, thus facilitating higher rates of production over prior art methods.
It is one object of the present invention to expedite changing the breech electrode of an electrothermal gun.
It is another object of the present invention to eliminate material waste by providing for complete consumption of the breech electrode without leaving a stub or heel.
The foregoing objects are achieved by modifying the design of the electrothermal gun to simplify installation of the breech electrode. The modified design is open at both ends, and the breech electrode is replaced by a central electrode. In operation, two opposing electrothermal jets are produced, one exiting from each of the two open ends of the gun. There are no mechanical electrical (i.e., direct) connections to the central electrode. Current is transferred to the central electrode by two arcs, one arc attaching to each end of the central electrode. There is little or no pressure differential between the two ends of the central electrode, so the need to provide a seal is eliminated. Also, if a pressure differential does develop between the two ends of the central electrode, there is no adverse consequence to the leakage of plasma and molten metal across the central electrode.
The above as well as additional objectives, features, and advantages of the present invention will become apparent in the following detailed written description.

Method and apparatus for direct electrothermal-physical conversion of ceramic into nanopowder


A rotating machine is provided, including a rotor and a stator set. The rotor rotates around an axis, wherein the rotor includes a first permanent magnet set and a second permanent magnet set, the first permanent magnet set is magnetized in a circumference direction of the axis, and the second permanent magnet set is magnetized in an axial direction of the axis. The stator set corresponds to the rotor, wherein the stator set includes a radial stator member and an axial stator member, the axial stator member corresponds to the rotor in the axial direction of the axis, and the radial stator member corresponds to the rotor in a radial direction of the axis.

1. Field of the Invention
The present invention relates to a rotating machine, and in particular relates to a rotating machine and a rotor having increased unit volume capacity.
2. Description of the Related Art
A conventional rotating machine is composed of a stator and rotor. The stator is arranged corresponding to the rotor, and the rotating machine is rotated by magnetic force generated between the rotor and the stator.
A conventional rotating machine having distributed windings has good torque, inductance and flux weakening performance. However, the conventional rotating machine having distributed windings has grooves crossing across a large amount of silicon steel sheets, and a stator coil is coiled on an end portion of the stator. The length of the end portion of the stator is therefore increased, the length of the coil is increased, an additional radial or axial space occupies the stator, and unit volume capacity is reduced.
Recently, rotating machines having planar structure are popular due to their heat dissipation advantages over other like machines.


A production process for producing a hollow steel tube of a high strength includes the steps of a tube preparation step of producing a seamless steel tube of a heavy thickness containing flaws of less than 0.25 mm in depth in an inner periphery thereof, a tube inner periphery correction step of correcting at least the flaws having a width of 0.001 mm or less so as to have a depth of 0.15 mm or less, and a hardening step of hardening the seamless steel tube across a whole thickness thereof to a hardness of from 450 to 670 in Vickers hardness (Hv). The production process enables not only to produce a hollow steel tube of a high strength at a less production cost but also to adapt it to exhibit such a high torsional fatigue fracture resistance and a high impact strength that it is applicable to axles for large size automobiles producing high outputs.

1. Field of the Invention
The present invention relates to a production process for producing a hollow steel tube of a high strength which is applicable to automobile axles, or the like.
2. Description of the Related Art
There have been the lightweight requirements for vehicles such as automobiles, or the like. Accordingly, axles have been examined to hollow them out, and part of such attempts have been put into actual applications. The specifications of such hollow axles which have been put into actual applications by certain automobile manufactures are identical with each other more or less, and they can be summarized as follows:
Material Quality: S45C through S50C (as per Japanese Industrial Standard), carbon steel for mechanical structures, or the equivalents;
Hollowing Rate: approximately 50%, and the ratio of the inside diameter (hereinafter abbreviated to "I.D.") to the outside diameter (hereinafter abbreviated to "O.D."), i.e., I.D./O.D., falling in a range of from 0.45 to 0.55;
Hollowing Way: Drilling round bar stocks with a gun drill followed by reaming; and
Heat Treatment: Induction hardening followed by tempering (Here, the hardening is carried out up to about a half of the thickness of the hollow axles.)
The S45C through S50C carbon steels were used to make the conventional hollow axles because the inner hardness was intended to be as high as possible in the unhardened portions while maintaining such high carbon contents that there arise no cracks resulting from the hardening.
Namely, when the induction hardening is carried out too deep, the crystalline grains become so coarse that the resulting hollow axles are deteriorated in the impact strength. Accordingly, the heat treatment is limitedly carried out only up to about a half of the thickness of the conventional hollow axles. Therefore, the conventional hollow axles hardened to the shallow depths cannot be applied to large size vehicles which produce high outputs, because they lack the torsional fatigue fracture resistances. It has been known that the torsional fatigue fracture resistances of the automobile axles depend greatly on the induction hardened depth. FIG. 17 illustrates the relationship between the torsional resistances and the hardened depths, relationship which was exhibited by the conventional hollow axles hardened to such shallow depths. In FIG. 17, solid diamonds ( ) designate the torsional resistance exhibited by the conventional hollow axles made from "TS" No. 1, and blank circles (.largecircle.) designate the torsional resistance exhibited by the conventional hollow axles made from "TS" No. 3. As illustrated in FIG. 17, the conventional hollow axles exhibited sharply deteriorating torsional resistances when the ratios of the hardened depths to the radii were 0.6 or less. Here, the conventional hollow axles were examined for the torsional resistances by twisting them with an increasing torque until they ruptured or broke.
With respect to the hollowing way, the conventional hollow axles were bored by machining the round bar stocks because there are no alternative ways available. In view of the productivity, it takes a long processing tact-time for such boring with the drill to complete hollowing out a round bar stock, and consequently it is needed to provide a plurality of the facilities therefor. As a result, the manufacturing cost for the conventional hollow axles increases sharply because of the costs of the facilities and the spaces to be secured in a manufacturing plant. Thus, it is impossible to actually hollow out all the axles for all types of vehicles currently manufactured.
As for the other hollowing way, one can think of using electrically-welded steel tubes, for example. However, it is impossible to produce electrically-welded tubes which have heavy thicknesses appropriate for the manufacture of the vehicle axles, because they are formed into the tubular shapes by welding thin steel strips.
Further, the production process for seamless steel tubes can make hollow steel tubes of desired sizes, e.g., I.D.'s. and O.D.'s., at the least expensive cost. However, in the manufacture of the seamless steel tubes, it is inevitable that the seamless steel tubes contain flaws in the peripheries. The flaws in the outer peripheries of the seamless steel tubes can be machined out in one of the manufacturing processes of the vehicle axles, but the flaws in the inner peripheries thereof are left as they are in the end. In addition, no analysis has been made extensively so far in order to verify how wide and deep the flaws can be so as not to render them the starting points of fatigue fracture in the resulting hollow steel tubes.
For instance, the present inventors examined the seamless steel tubes, which had I.D.'s and O.D.'s applicable to hollow axles, for the flaws, and they found that the seamless steel tubes contained the flaws of 0.3 mm in depth. These flaws are believed to result from the scratches which are caused by a rolling and boring machine in the boring process of the seamless steel tubes production process. Namely, the scratches are believed to be folded into the inner peripheries of the seamless steel tubes when the seamless steel tubes are drawn and rolled to a predetermined thickness, i.e., to a half of the differences between O.D.'s and I.D.'s, by a stretching reducer, and they are believed to be left in the inner peripheries as the flaws of such a deep depth.

Production process for producing hollow steel tube of high strength