Various medical implants and methods of using the implants are disclosed. In an embodiment, the implants include piezoelectric polymers for treating unwanted medical conditions of a patient. The medical implants may be delivered to an organ of the patient to treat conditions of those organs.

The present invention relates to electrical stimulation and thermal therapies for various medical conditions. More particularly, embodiments of the present invention relate to medical implants that include piezoelectric materials and/or heating elements, and methods of using the implants to treat unwanted conditions in a patient.
Coronary Heart Disease is the leading cause of death in the Western world making it an important public health concern. Acute Myocardial Infarction (AMI) events play a key role in Coronary Heart Disease. In addition to being potentially lethal, AMI may lead to the development of congestive heart failure (CHF), a leading cause of hospitalization after AMI. The cornerstone of AMI management aims for myocardial salvage and prevention of complications caused by the event. Medical efforts are focused on increasing the supply of oxygen to the myocardium through primary angioplasty, thrombolytic therapeutics, and coronary vasodilation (nitroglycerin), and at the same time reducing ischemic myocardium oxygen consumption via β-blockers and angiotensin-converting enzyme (ACE) inhibitors. Ancillary therapeutics or anticoagulants such as non-fractionated heparin, low molecular weight heparin, or lipid lowering statins may also be administered to reduce the recurrence of ischemic events. Despite the existence of these therapies, additional therapies to manage the impacts of AMI are needed.
Electrical stimulation may be used as a pro-healing trigger after an AMI event. One potential target for electrical stimulation is angiogenesis. As angiogenesis takes place in tissue, the surrounding endothelial cells are exposed to an electric field due to the active ion transport across the epithelia. Research has attempted to control angiogenesis using electric fields and has succeeded in showing that electrical stimulation induces significant angiogenesis in vivo, possibly as a result of an observed increase in vascular endothelial growth factor (VEGF) in muscle cells. Thus, studies suggest that electric field generation could play a positive role in post-infarct healing by inducing or supporting angiogenesis.
In addition to electrical stimulation, thermal stimulation has been shown to induce healing in cardiac cells and tissue in the form of revascularization and angiogenesis. In infarcted myocardium, necrotic tissue is gradually replaced by scar tissue, which often leads to further diastolic dysfunction resulting from the limited contractile properties of scar tissue. Additionally, post-infarcted myocardium sees cardiomyocytes replaced by myofibroblasts, which do not have the functionality necessary for cardiac contraction. However, thermal stimulation of infarcted myocardium may positively affect the myocardial healing process and aid in regaining cardiac function. Thermal stimulation of cardiac tissue may induce heat shock protein (HSP) expression, which provides cardiac protection and maintains tissue viability. Thermal stimulation has also been shown to impact cell migration, which is essential in replacing ischemic tissue with new functional tissue. Such replacement involves cell replication that occurs until the injured area is covered with cells. Therefore, thermal stimulation can cause cell migration, potentially encouraging endothelial cells to repopulate the site of injury and triggering cardiomyocyte reorganization.
Thermal stimulation can also induce growth factor production and capillary growth. The application of heat causes vasodilation to occur and increases the permeability of the vascular wall. This mechanism increases the antioxidative enzyme, catalase, which aids in reperfusion recovery. Thus, thermal stimulation can lead to cell differentiation and capillary growth by triggering growth factor production.
Like Coronary Heart Disease, diabetes is another medical condition with a high global incidence. Glucagon-like-peptide-1 (GLP-1) is a hormone derived from the transcription product of the pro-glucagon gene. GLP-1 has been shown to play a central role in glucose tolerance and has thus raised questions about its possible involvement in the pathogenesis of diabetes. The major source of GLP-1 in the body is the intestinal L cell that secrete GLP-1 as a gut hormone. The infusion of native GLP-1 using an insulin pump has been studied, but the use of native GLP-1 to treat diabetic patients is limited because the peptide cannot be taken orally and because it is rapidly metabolized in the circulatory system. Accordingly, methods of stimulating the production of GLP-1 in the gut may prove to be a useful therapy for diabetes. Recent evidence suggests that small intestinal electrical stimulation reduces food intake, although the mechanism of action is debated.


A method performed by a first radio network node for handling mobility of a wireless device in a wireless communication network. The first radio network node provides radio coverage over a first service area using a first reference signal for identifying the first service area in the wireless communication network. A second radio network node provides radio coverage over a second service area using a second reference signal for identifying the second service area in the wireless communication network. The first radio network node receives a measurement report from the second radio network node, which measurement report indicates a second signal strength or quality of a second dedicated beam used for data transmission for wireless devices in the second service area. The first radio network node performs a mobility decision for the wireless device taking the second signal strength or quality, indicated in the received measurement report, into account.

In a typical wireless communication network, wireless devices, also known as wireless communication devices, mobile stations, stations (STA) and/or user equipments (UE), communicate via a Radio access Network (RAN) to one or more core networks (CN). The RAN covers a geographical area which is divided into service areas or cell areas, with each service area or cell area being served by radio network node such as an access node e.g. a Wi-Fi access point or a radio base station (RBS), which in some networks may also be called, for example, a "NodeB" or "eNodeB". The service area or cell area is a geographical area where radio coverage is provided by the access node. The access node operates on radio frequencies to communicate over an air interface with the wireless devices within range of the access node. The access node communicates over a downlink (DL) to the wireless device and the wireless device communicates over an uplink (UL) to the access node.
A Universal Mobile Telecommunications System (UMTS) is a third generation telecommunication network, which evolved from the second generation (2G) Global System for Mobile Communications (GSM). The UMTS terrestrial radio access network (UTRAN) is essentially a RAN using wideband code division multiple access (WCDMA) and/or High-Speed Packet Access (HSPA) for communication with user equipments. In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for present and future generation networks and UTRAN specifically, and investigate enhanced data rate and radio capacity. In some RANs, e.g. as in UMTS, several access nodes may be connected, e.g., by landlines or microwave, to a controller node, such as a radio network controller (RNC) or a base station controller (BSC), which supervises and coordinates various activities of the plural access nodes connected thereto. The RNCs are typically connected to one or more core networks.
Specifications for the Evolved Packet System (EPS) have been completed within the V Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases, such as 4G and 5G networks. The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also known as the Long-Term Evolution (LTE) radio access network, and the Evolved Packet Core (EPC), also known as System Architecture Evolution (SAE) core network, E-UTRAN/LTE is a 3GPP radio access technology wherein the access nodes are directly connected to the EPC core network. As such, the Radio Access Network (RAN) of an EPS has an essentially "flat" architecture comprising access nodes connected directly to one or more core networks.
With the emerging 5G technologies, the use of very many transmit- and receive-antenna elements is of great interest as it makes it possible to utilize beamforming, such as transmit-side and receive-side beamforming. Transmit-side beamforming means that the transmitter can amplify the transmitted signals in a selected direction or directions, while suppressing the transmitted signals in other directions. Similarly, on the receive-side, a receiver can amplify signals from a selected direction or directions, while suppressing unwanted signals from other directions.
Beamforming allows the signal to be stronger for an individual connection. On the transmit-side this may be achieved by a concentration of the transmitted power in the desired direction(s), and on the receive-side this may be achieved by an increased receiver sensitivity in the desired direction(s). This beamforming enhances throughput and coverage of the connection. It also allows reducing the interference from unwanted signals, thereby enabling several simultaneous transmissions over multiple individual connections using the same resources in the time-frequency grid, so-called multi-user Multiple Input Multiple Output (MIMO).
Overall requirements for the Next Generation (NG) architecture e.g. TR 23.799 v. 0.5.0, and, more specifically the NG Access Technology, e.g. TR 38.913 v. 0.3.0 will impact the design of the Active Mode Mobility solutions for the New Radio Access Technology (NR), see RP-160671 New SID Proposal: Study on New Radio Access Technology, DoCoMo, compared to the current mobility solution in LTE. Some of these requirements are the need to support network energy efficiency mechanisms, future-proof-ness and the need to support a very wide range of frequencies e.g., up to 100 GHz.
One of the main differences, with respect to LTE, comes from the fact that propagation in frequencies above the ones allocated to LTE is more challenging so that the massive usage of beamforming becomes an essential component of NR. Despite the link budget gains provided by beamforming solutions, reliability of a system purely relying on beamforming and operating in higher frequencies might be challenging, since the coverage might be more sensitive to both time and space variations. As a consequence of that a Signal to Interference plus Noise Ratio (SINR) of a narrow link can drop much quicker than in the case of LTE, see R2-162762, Active Mode Mobility in NR: SINR drops in higher frequencies, Ericsson.
To support Transmit (Tx)-side beamforming at a radio network node, a number of reference signals may be transmitted from the radio network node, whereby the wireless device can measure signal strength or quality of these reference signals and report the measurement results to the radio network node. The radio network node may then use these measurements to decide which beam(s) to use for the one or more wireless devices.
A combination of periodic and scheduled reference signals may be used for this purpose.
The periodic reference signals, typically called beam reference signals (BRS) or Mobility Reference Signals (MRS), are transmitted repeatedly, in time, in a large number of different directions using as many Tx-beams as deemed necessary to cover a service area of the radio network node. As the naming indicates, each BRS represents a unique Tx-beam from that radio network node. This allows a wireless device to measure the BRS when transmitted in different beams, without any special arrangement for that wireless device from the radio network node perspective. The wireless device reports e.g. the received powers for different BRSs, or equivalently different Tx-beams, back to the radio network node.
The scheduled reference signals, called channel-state information reference signals (CSI-RS), are transmitted only when needed for a particular connection. The decision when and how to transmit the CSI-RS is made by the radio network node and the decision is signalled to the involved wireless devices using a so-called measurement grant. When the wireless device receives a measurement grant it measures on a corresponding CSI-RS. The radio network node may choose to transmit CSI-RSs to a wireless device only using beam(s) that are known to be strong for that wireless device, to allow the wireless device to report more detailed information about those beams. Alternatively, the radio network node may choose to transmit CSI-RSs also using beam(s) that are not known to be strong for that wireless device, for instance to enable fast detection of new beam(s) in case the wireless device is moving.
The radio network nodes of a NR network transmit other reference signals as well. For instance, the radio network nodes may transmit so-called demodulation reference signals (DMRS) when transmitting control information or data to a wireless device. Such transmissions are typically made using beam(s) that are known to be strong for that wireless device.
Beamforming introduces a possibility to enhance the signal towards a specific location. This enables better signal to noise ratio towards a specific wireless device.
A specific beamforming towards a specific wireless device is handled per Transmission Time Interval (TTI) where a number of factors and measurements are used to determine how the beamforming should look like. With an increasing number of antenna elements, the number of possible beams that theoretically can be created increases a lot.
When performing mobility measurements, it will be quite difficult to create all or the best of any possible beams that is optimal from a location of the wireless device on which the specific wireless device can perform its measurement evaluation needed for mobility triggers. Instead a reasonable number of static beams are created, upon request or configured, that are supposed to cover a specific service area. An increasing number of static beams improves the possibility to get as accurate measurement as possible towards a specific location, but it also increases energy consumption and increases complexity in the RAN system, due to complex configuration, planning etc. The number of static beams to perform generic mobility measurements on is supposed to be a lot less than the dedicated beams possible to beam-form towards a specific wireless device in any location of the coverage area served by the radio network node.
The difference in characteristics of a mobility measurement beam, called a MRS beam or a static beam, and a fully dedicated beam for data transmission towards a specific wireless device, also referred to as UE dedicated beam or dedicated beam for data transmission, also creates a difference in what is measured on and what the result will be if the mobility action is performed and a dedicated beam for data transmission is created towards the wireless device. This may lead to wrong decisions when to perform a beam switch or not. In FIG. 1 the fully lined beam represents the mobility measurement beam and the dashed line beam represents a dedicated beam for data transmission towards a specific wireless device. Thus, it is shown a difference between the mobility measurement signal strength and the UE dedicated, beam-formed, beam signal strength.
In FIG. 2, there is one wireless device and three radio network nodes, AN1, AN2 and AN3, each radio network node provides a respective mobility measurement beam and each radio network node also has one dedicated beam for data transmission towards the wireless device. Note that the dedicated beam for data transmission normally only exists from the radio network node currently serving the wireless device, due to that this type of beam needs a lot of ongoing measurements and feedback from the wireless device to be shaped correctly, and these measurements and feedback are normally only available to the radio network node currently serving the wireless device with data transmissions. A mobility decision for the wireless device based on measurements on mobility measurement beams may lead to a non optimal decision resulting in a reduced or limited performance of the wireless communication network.

Wireless device, radio network nodes, and methods performed therein for handling mobility in a wireless communication network


A leadless plastic chip carrier comprising a die attach pad, a semiconductor die mounted to a portion of the die attach pad and at least one row of contact pads circumscribing the die attach pad. The row of contact pads have a thickness greater than the thickness of the portion of the die attach pad. A plurality of wire bonds connect the die attach pad and the contact pads. An overmold covers the semiconductor die and all except one surface of the at least one row of contact pads and the die attach pad.

The present invention relates in general to integrated circuit packaging, and more specifically to an improved leadless plastic chip carrier which includes a unique die attach pad feature.
According to well known prior art IC (integrated circuit) packaging methodologies, semiconductor dice are singulated and mounted using epoxy or other conventional means onto respective die pads (attach paddles) of a leadframe strip. Traditional QFP (Quad Flat Pack) packages incorporate inner leads which function as lands for wire bonding the semiconductor die bond pads. These inner leads typically require mold locking features to ensure proper positioning of the leadframe strip during subsequent molding to encapsulate the package. The inner leads terminate in outer leads that are bent down to contact a mother board, thereby limiting the packaging density of such prior art devices.
In order to overcome these and other disadvantages of the prior art, the Applicants previously developed a Leadless Plastic Chip Carrier (LPCC). According to Applicants"" LPCC methodology, a leadframe strip is provided for supporting up to several hundred devices. Singulated IC dice are placed on the strip die attach pads using conventional die mount and epoxy techniques. After curing of the epoxy, the dice are gold wire bonded to peripheral internal leads. The leadframe strip is then molded in plastic or resin using a modified mold wherein the bottom cavity is a flat plate. In the resulting molded package, the die pad and leadframe inner leads are exposed. By exposing the bottom of the die attach pad, mold delamination at the bottom of the die attach pad (paddle) is eliminated, thereby increasing the moisture sensitivity performance. Also, thermal performance of the IC package is improved by providing a direct thermal path from the exposed die attach pad to the motherboard. By exposing the leadframe inner leads, the requirement for mold locking features is eliminated and no external lead standoff is necessary, thereby increasing device density and reducing package thickness over prior art methodologies. The exposed inner leadframe leads function as solder pads for motherboard assembly such that less gold wire bonding is required as compared to prior an methodologies, thereby improving electrical performance in terms of board level parasitics and enhancing package design flexibility over prior art packages (i.e. custom trim tools and form tools are not required). These and several other advantages of Applicants"" own prior art LPCC process are discussed in Applicants"" U.S. Pat. No. 6,229,200, issued May 8, 2001, the contents of which are incorporated herein by reference.
Applicants"" LPCC production methodology utilizes saw singulation to isolate the perimeter I/O row as well as multi-row partial lead isolation. Specifically, the leadframe strip is mounted to a wafer saw ring using adhesive tape and saws-singulated using a conventional wafer saw. The singulation is guided by a pattern of fiducial marks on the bottom side of the leadframe strip. Also, special mold processing techniques are used to prevent the mold flow from bleeding onto the functional pad area and inhibiting electrical contact. Specifically, the exposed die pad surface is required to be deflashed after molding to remove any molding compound residue and thereby allow the exposed leads and die attach pad to serve as solder pads for attachment to the motherboard.
According to Applicants"" co-pending U.S. patent application Ser. No. 09/288,352, the contents of which are incorporated herein by reference, a localized etch process is provided for the improved manufacture of the LPCC IC package. The leadframe strip is subjected to a partial etch on one or both of the top and bottom surfaces in order to create a pattern of contact leads (pads) and a die attach pad (paddle).
Although these prior art processes yield IC package designs with improved electrical performance over the prior art, it is desirable to further increase package density and thereby reduce the length of the gold wire bonds.
Accordingly, it is an object of the present invention to provide an improved leadless plastic chip carrier which includes a post mold etch back step and a unique die attach pad feature.
According to an aspect of the present invention, a new leadless plastic chip carrier is provided. The leadless plastic chip carrier has a die attach pad, a semiconductor die mounted to a portion of the die attach pad and at least one row of contact pads circumscribing the die attach pad. The contact pads have a thickness greater than the thickness of the portion of the die attach pad. A plurality of wire bonds connect the die attach pad and the contact pads and an overmold covers the semiconductor die and all except one surface of the contact pads and the die attach pad.
According to another aspect of the present invention, a new process for fabricating a leadless plastic chip carrier is provided. The process has the steps of: depositing a photo-imageable etch resist on opposing first and second surfaces of a leadframe strip; imaging and developing the etch resist to define a pattern for a die attach pad and at least one row of contact pads; etching the leadframe strip to define the contact pads and the die attach pad such that at least a portion of the die attach pad has a thickness less than the thickness of the contact pads; mounting the semiconductor die to the portion of the die attach pad; wire bonding the semiconductor die to the contact pads; and encapsulating the first surface of the leadframe strip in a molding material.
It is an advantage of an aspect of the present invention that the semiconductor die sits in a portion of the die attach pad that is reduced in thickness and therefore the length of the wire bonds (both to the die attach pad (ground bonds) and to the external pads (I/O bonds) can be reduced. Because electrical impedance in an IC package is directly related to the wire length, this construction allows for a LPCC package suitable to operate an higher frequencies compared to the prior art packages.
A further advantage of an aspect of the present invention is provided by the three dimensional nature of the partial etch die attach pad. This pad provides additional exposed metal for the mold compound to adhere to, thereby providing a more robust package.
Still further, it is an advantage of an aspect of the present invention that the die and wire bonds are lower in the profile of the package. This allows the option of using a thinner mold cap to further reduce the package profile.

Leadless plastic chip carrier with partial etch die attach pad


Fluorocarbon- and urethane-(meth)acryl-containing additives and hardcoats. The hardcoats are particularly useful as a surface layer on an optical device.

Optical hard coats are applied to optical display surfaces to protect them from scratching and marking. Desirable product features in optical hard coats include durability to scratches and abrasions, and resistance to inks and stains.
Materials that have been used to date for surface protection include fluorinated polymers, or fluoropolymers. Fluoropolymers provide advantages over conventional hydrocarbon based materials in terms of high chemical inertness (solvent, acid, and base resistance), dirt and stain resistance (due to low surface energy), low moisture absorption, and resistance to weather and solar conditions.
Fluoropolymers have also been investigated that are crosslinked to a hydrocarbon-based hard coating formulation that improves hardness and interfacial adhesion to a substrate. For example, it is known that free-radically curable perfluoropolyethers provide good repellency to inks from pens and permanent markers when added to ceramer hard coat compositions, which comprise a plurality of colloidal inorganic oxide particles and a free-radically curable binder precursor, such as described in U.S. Pat. No. 6,238,798 to Kang, and assigned to 3M Innovative Properties Company of St. Paul, Minn.
Industry would find advantage in other fluoropolymer-based hard coatings, particularly those having improved properties.

This patent is subject to a terminal disclaimer.

Perfluoropolyether urethane additives having (meth)acryl groups and hard coats


Video of an above ground effect of a subterranean event is received. The subterranean event is identified using Eulerian video magnification of the received video.

The present disclosure relates to monitoring subterranean events using enhanced video.
Recognizing, quantifying and otherwise identifying subterranean events present a perpetual challenge in engineering and in accessing subterranean resources. The challenge, of course, stems from the fact that these events are under ground, and thus cannot be easily accessed, seen or measured. In some instances, the above-ground effects of subterranean events can aid in such identification. For example, an underground explosion, well control event, or other subterranean event might cause surface effects in the form of vibration or other movement of surface objects such as trees, soil, equipment, or other structures. In the case of a large-magnitude subterranean event occurring near the surface, such surface movement (or other above-ground effects) may be easily visible to the unaided naked eye. In other instances, such surface effects may be only minimally detectible, or completely below the threshold of detection, by the unaided naked eye. Sensors, used in a wellbore or at the surface, are conventionally employed to recognize and quantify subterranean events by measure characteristics of the event. However, sensors typically only measure the characteristics only at point locations, and sensors in many existing systems must be placed on or in direct contact with the region or media being sensed. Thus, operators must make do with few sensors and the corresponding limited data produced by the sensors or bear the expense and complexity of placing, communicating with and maintaining a complex sensor network. Moreover, complex sensor networks are often infeasible in remote, inaccessible, and/or underdeveloped locations.
Like reference symbols in the various drawings indicate like elements.

Subterranean monitoring using enhanced video


A harvester includes a measuring device for detecting a grain number of a crop flow, in which a sensor of the measuring device detects via a measuring signal kernels impacting an impact surface of the measuring device, and a processing unit of the measuring device is arranged to detect and calculate the grain number by using the measuring signal, wherein the rising edges of the measuring signal are recorded and form a measurement for the grain number. Furthermore, the measuring device for detecting a grain number and method for detecting a grain number are also provided.

To increase the efficiency when harvesting with a combine harvester, the working bodies of the threshing unit, the separation unit or the cleaning unit are today increasingly controlled automatically via performance curves and/or measuring signals. To precisely adjust the process parameters and also determine the grain loss, an accurate determination of the grain output of different mechanical functional units and working bodies is extremely important. At the same time, the grain output and grain loss can be determined by means of grain output sensors in the form of structure-borne sound sensors, light barrier sensors or capacitive sensors. Structure-borne sound sensors have the advantage of being cost-effective and robust. Their operating principle is based on determining the impact energy of a kernel impacting the impact surface. This results in mechanical vibrations, which are converted to an electrical measuring signal by means of a sound converter/piezo element. The measuring signal may be evaluated in different ways in order to obtain information regarding the volume of kernels impacting the surface.
For example, the publication DE 10 2006 015 152 A1 discloses a method for grain volume determination, in which the partial surface arranged below an amplitude of a measuring signal is used as measurement for the number of kernels impacting a structure-borne sound sensor. However, the vibration amplitude depends on the grain moisture and the speed of the kernel and therefore on the temperature and moisture of the surrounding area, as well as on machine parameters. Therefore, with this method, kernels with different vibration amplitudes are evaluated differently when the grain number is detected. This results in inaccurate measurement, which are affected by environmental conditions and machine parameters.
The publication EP 0 166 137 A2 describes a method for acoustically counting particles, in which a vibration amplitude of a measuring signal measured at a structure-borne sound sensor is compared with a characteristic reference signal. If the amplitude of the measured vibration signal is smaller than that of the reference signal, a particle is counted. If the amplitude is greater the impact of a following particle is assumed. Because of the required comparison between the measuring signal and the reference signal, this method is complex. Moreover, it became apparent that it may no longer fulfills the current requirements of accuracy.

Harvester having a measuring device for grain number detection

CLAAS Selbstfahrende Erntemaschinen GmbH


An actuator mechanism that decreases the time needed to move the contacts of a circuit interrupter between a closed circuit position and an open circuit position to reduce the probability of the occurrence of restrikes. The actuator mechanism uses a toggle spring arrangement that uses a single spring to move the interrupter through both an opening stroke and a closing stroke. The interrupter is designed to connect to the circuit in parallel, so that the interrupter is not normally in the circuit when the circuit is closed. Because the interrupter is not normally in the circuit, it can be manufactured to less stringent standards than those that apply to electrical components that normally remain in the circuit. The interrupter is well adapted for use as a puffer-type interrupter in which the contacts of the interrupter are contained in an arc-extinguishing gas, such as sulphur-hexaflouride (SF6) gas to further reduce the probability of restrikes and to minimize the effect of occurring restrikes. The interrupter has a bellows arrangement that provides a seal to contain the sulphur-hexaflouride (SF6) gas while allowing the actuator mechanism to freely operate without deterioration of interrupter components. The bellows arrangement enables the interrupter to be utilized in capacitor switching applications in which frequent switching is required. The interrupter may also include a voltage-clamping device connected in parallel across the contacts of the circuit interrupter.

The present invention relates to electric power circuit interrupters and, more particularly, relates to a circuit interrupter with limited restrike capability suitable for use as a line capacitor and load switch. The interrupter, which is disconnected from the circuit in normal operation, includes a bidirectional freewheeling toggle mechanism and a bellows around a relatively slow moving actuator shaft to minimize wear and tear imposed on the interrupter through repetitive cycles.
A circuit interrupter is a disconnect switch used to periodically disconnect and reconnect an electrical power transmission, sub-transmission or distribution line from a connected device, such as a load, a line capacitor, a voltage regulator, or another type of device. Circuit interrupters typically include two or more contacts that are in physical contact with one another when the electric power line is connected to the switched device, and that are physically separated when the line is disconnected from the switched device. The interrupter is said to be in the xe2x80x9cclosed positionxe2x80x9d when the contacts are in contact with each other, and in the xe2x80x9copen positionxe2x80x9d when the contacts are separated.
For an electric power line that carries high voltage and/or high current, it is desirable to open the male and female contacts quickly to avoid a restrike, in which the electric current arcs across a physical gap between the contacts. Restrikes impose high current spikes and serious voltage disturbances on the power line, and can also physically degrade the components of the interrupter, especially the contacts. These current spikes and voltage disturbances can also damage other pieces of equipment connected to the power line. Sensitive loads, such as computers and other electronic devices, are particularly vulnerable to this type of damage. Generally, the wider the arc gap during a restrike, the higher the voltage required to breakdown the gap, and the larger the current spike and the associated risk of damage.
Restrikes occur when the interrupter""s contacts are not in physical contact, but are still close enough to each other to permit electric current to arc through the air or other media between the contacts. When the contacts of a properly designed circuit interrupter are fully separated, the distance between the contacts is sufficient to prohibit restrikes. However, a restrike can occur as the contacts are moved through an xe2x80x9copening strokexe2x80x9d from the fully connected or closed position to the fully separated position or open position. Likewise, an arc can occur across a gap between the contacts as the contacts are moved through a xe2x80x9cclosing strokexe2x80x9d from the open position to the closed position. However, arcs during a closing stroke are less dangerous to the electric system because the current in the circuit is zero prior to reconnection, which greatly reduces the current spike caused by the arc. Nevertheless, for safety reasons it may desirable to control the arcs during reconnection of the circuit interrupter.
Restrikes typically occur because once the circuit is opened at a zero voltage crossing, there is a rapid rise in voltage across the contacts known as the xe2x80x9ctransient recovery voltage.xe2x80x9d If the interrupter""s contacts are not separated quickly enough for the gap between the contacts (the xe2x80x9carc gapxe2x80x9d) to withstand this rising voltage, then the gap breaks down and the current flow arcs across the gap and results in a restrike. A first restrike generally occurs at or near the point when the transient recovery voltage reaches its maximum value, which is typically one-quarter of a cycle from the zero voltage crossing when the circuit was initially opened. Thus, to prevent a restrike, the contacts must be moved from the closed position to a position at which a restrike is impossible within one-quarter of a cycle.
On an opening stroke in which the arc gap increases quickly, a second restrike is much more severe than the first because the arc gap is much larger. For this reason, in certain applications a maximum of one restrike is permitted. To meet this one-restrike-maximum, the contacts must be moved from the fully connected position to a position at which a restrike is impossible within three-quarters of a cycle. In particular, governmental regulations and municipal codes generally permit a maximum of one restrike per transmission or distribution line disconnection. Thus, the actuator mechanism of a typical interrupter must be capable of opening the contacts at a separation velocity sufficient to prevent multiple restrike (i.e., more than one) once the initial arc extinction occurs at a current zero.
Usually, a human operator of an interrupter cannot create enough energy to separate the contacts of an interrupter in a short enough time without a mechanical advantage. Thus, separation velocity is typically provided by an actuator mechanism, usually a spring arrangement, in the circuit interrupter. A typical spring arrangement stores potential energy in a spring-type actuator mechanism and then releases the spring energy abruptly to produce the desired separation velocity. Of course, higher separation velocity can often be accomplished by a more robust actuator mechanism. However, the designer of the circuit interrupter is also concerned with the cost and durability of the resulting device.
The designer therefore takes the intended use of the circuit interrupter into account when designing the circuit interrupter. For example, disconnection is often required to perform maintenance on the electrical power line or on a device connected to the line downstream from the disconnect switch, such as a transformer or voltage regulator. A disconnect capability may also be required for fault protection. A conventional circuit breaker is typically used as the circuit interrupter for these applications. In this application, the circuit breaker can be expected to cycle several dozen or a hundred or so times over its life span.
Line capacitor switches, on the other hand, can be expected to cycle much more frequently. This is because a line capacitor is typically switched into connection with the electric power line to correct the power factor during high-load periods. The line capacitor is later switched out of the circuit when the load drops and the power factor correction afforded by the capacitor is no longer needed. Because electric power loads typically peak on a daily or twice-daily basis, capacitor switches typically cycle on a daily or twice-daily basis. In addition, certain types of industrial loads, such as coal mines and arc furnaces, often impose peak loads many times each day. Therefore, a capacitor switch can be expected to cycle hundreds or thousands of times over its life span. A load switch, which is typically used to disconnect a discrete distribution voltage load such as customer-owned device or premises, may also experience hundreds or thousands of cycles over a lifetime.
In addition, it is economically feasible to design very expensive transmission voltage circuit breakers to provide fault protection for the transformer, which is a very expensive device. In addition, multiple restrikes at very high voltages can damage the transformer and other connected devices. Transmission voltage circuit breakers have therefore been designed with very robust actuator mechanisms, xe2x80x9cpenetrating contactsxe2x80x9d (e.g., a male xe2x80x9cpinxe2x80x9d contact and a female xe2x80x9ctulipxe2x80x9d contact) that fit into each other, sealed chambers that surround the penetrating contacts with a dielectric gas that quenches the arcs within xe2x80x9carc gapsxe2x80x9d between the contacts, and nozzles that direct the dielectric gas into the arc gaps as the penetrating contacts separate. Although these features are very effective at minimizing restrikes, they have traditionally been too expensive to be feasible for inclusion in sub-transmission and distribution voltage devices, such as capacitor and load switches.
Conventional circuit breakers have a number of other attributes that make them unsuitable as capacitor or load switches. First and most importantly, circuit breakers are not designed to withstand the hundreds or thousands of cycles that capacitor and load switches must withstand. For example, circuit breakers typically include xe2x80x9cstopxe2x80x9d mechanisms for charging and then abruptly releasing spring energy. These stop mechanisms are prone to wear and tear and thus limit the durability of the circuit breaker. Bellows placed around high-speed actuators to seal the dielectric gas chambers are also prone to wear and tear through repetitive cycling of the breaker. A circuit breaker would therefore break down far to quickly to be cost effective if used as a capacitor switch. Second, circuit breakers are normally operated as series-connected devices, which raises their cost as compared to disconnect switches that are normally disconnected from the circuit and only conduct current when temporarily connected during disconnect operations. Third, circuit breakers typically include separate actuator mechanisms for opening and closing the breaker, which also raises their cost as compared to a disconnect switch that includes a single actuator mechanism.
Electric switchgear manufacturers have developed circuit interrupters for sub-transmission and distribution applications that overcome some of these disadvantages. For example, normally disconnected circuit interrupters have been developed for use as capacitor and load switches. However, these devices are not designed to prevent restrikes, but instead include a series connected cascade of sacrificial xe2x80x9cbuttxe2x80x9d contacts that are designed to deteriorate over time as a result of restrikes. The deterioration of the contacts requires regular maintenance to monitor and replace the contacts as they deteriorate, and thus increases the cost of using this type of circuit interrupter. These devices are also prone to cascading failures when one of the butt contacts deteriorates to the point of malfunction. These circuit interrupters are also designed to control the arc only on the opening stroke, and typically conduct an uncontrolled arc through air on the closing stroke.
Although transmission voltage circuit breakers are available with penetrating contacts, dielectric gas chambers, and actuators that accelerate the penetrating contacts to quench arcs between the contacts within the dielectric chambers during circuit opening, these features are not presently available in sub-transmission or distribution devices, such as capacitor and load switches. Moreover, circuit breakers with these features are not presently designed to be economical enough to serve as capacitor or load switches. Available capacitor and load switches, on the other hand, are not presently designed to avoid multiple restrikes or to accelerate their contacts to control the resulting arcs on both the opening and closing strokes. The limited durability of conventional capacitor switches with sacrificial contacts also limits their feasibility for many applications.
Therefore, there is a need for a circuit interrupter that prevents or limits restrikes, and that is durable enough to be used as a capacitor and load switch. There is a further need for a normally disconnected capacitor switch that controls the arc on both the opening and closing strokes. There is also a need for more durable and cost effective capacitor and load switch designs.
The circuit interrupter of the present invention meets these needs in circuit interrupter that includes many of the features of conventional circuit breakers, including a plunging contactor, a dielectric gas chamber, and an actuator mechanism that accelerates the plunging contactor during circuit opening. Unlike conventional circuit breakers, however, the circuit interrupter of the present invention includes these features in a normally disconnected device that opens and closes the circuit in response to physical movement of a conventional disconnect switch blade arm. These attributes allow the circuit interrupter to operate as a normally disconnected sub-transmission or distribution voltage disconnect switch.
In addition, the circuit interrupter includes a number of features that improve its operation over conventional circuit breakers or disconnect switches. These features improve the durability of the circuit interrupter and allow it to quench arcs within the dielectric gas chamber on both opening and closing strokes, which improves the operation of the device as a capacitor and load switch. In particular, the circuit interrupter includes a bidirectional freewheeling toggle mechanism that stores and then abruptly releases spring energy to accelerate the plunging contactor on both the opening and closing strokes. This allows the circuit interrupter to quench arch within the dielectric gas chamber on only the opening stroke, or on both the opening and closing strokes. This improves the safety of the circuit interrupter while allowing the device to avoid multiple restrikes on only the opening stroke, or on both the opening and closing strokes.
The freewheeling toggle mechanism improves the durability of the circuit interrupter as compared to conventional designs with stops that allow a spring to store and then release spring energy. The circuit interrupter also includes a bellows to seal the dielectric gas chamber around a relatively slow moving actuator shaft to minimize wear and tear imposed on the interrupter through repetitive cycles. The circuit interrupter may also be positioned so that the actuator arm meets the spacing requirements of electric codes, which allows the blade arm of a conventional disconnect switch to trigger the circuit interrupter on both the opening and closing strokes. These characteristics make the circuit interrupter particularly well suited to operation as a capacitor or load switch.
The circuit interrupter may also include a voltage-clamping device, such as a metal-oxide varistor, connected in parallel across the contacts of the interrupter. The xe2x80x9cbreak downxe2x80x9d or xe2x80x9ctripxe2x80x9d voltage for the voltage-clamping device is typically set at or near one per-unit (i.e., the maximum system voltage), which causes the voltage-clamping device to conduct electricity whenever the voltage across the interrupter exceeds the maximum system voltage. In this configuration, the parallel-connected voltage-clamping device may operate to discharge a capacitive load switched by the circuit interrupter. In addition, by limiting the voltage across the circuit interrupter, the parallel-connected voltage-clamping device prevents restrikes from occurring within the circuit interrupter when the voltage across the interrupter during operation would otherwise exceed the no-restrike design voltage of the interrupter. For example, the parallel-connected voltage-clamping device may prevent restrikes from occurring within the circuit interrupter during capacitor switching, when the voltage across the interrupter would approach two per-unit (i.e., double the maximum system voltage) if the voltage-clamping device was not present, and the two per-unit voltage level exceeds the no-restrike design voltage of the interrupter.
Generally described, the invention may be employed as an interrupter for an electric power circuit. A plunging contactor having first and second contacts moves in an opening stroke from a closed position to an open position to electrically open the circuit, and in a closing stroke from the open position to the closed position to reset the interrupter. A bidirectional freewheeling toggle mechanism stores and abruptly releasing spring energy to accelerate movement of the plunging contactor in both the opening and closing strokes. In addition, an actuator arm moves the toggle mechanism and thereby causes the toggle mechanism to store and then abruptly release the spring energy in both the opening and closing strokes. The freewheeling toggle mechanism may include a single spring that drives the toggle mechanism in both the opening and closing strokes.
The interrupter may also include a sealed interrupter chamber filled with a dielectric gas, such as sulphur-hexaflouride (SF6) gas. In this case, the plunging contactor is located within the dielectric gas chamber and a piston forces a flow of the dielectric gas into an arc gap defined by a separation between the first and second contacts on both the opening and closing strokes. The gas flow is enhanced by a nozzle that directs the flow into the arc gap at a predetermined distance from the first or second contact, such as 1.5 inches. In particular, the toggle mechanism typically accelerates the plunging contactor to a separation velocity of at least about 100 inches per second when then arc gap reaches 1.5 inches during the opening stroke. On the closing stroke, the toggle mechanism accelerates the plunging contactor to a reconnection velocity of at least about 80 inches per second when then arc gap reaches 1.5 inches.
When the interrupter operates as a disconnect switch, the actuator arm is positioned to be movable from an initial position (i.e., lowered in a typical disconnect switch configuration) to an opposing position (i.e., raised in a typical disconnect switch configuration) by a conventional disconnect switch blade arm as the blade arm moves from a closed position (i.e., lowered in a typical disconnect switch configuration) to an open position (i.e., raised in a typical disconnect switch configuration) to trigger the opening stroke of the plunging contactor. When the blade arm is in the closed position, it electrically connects to a jaws to provide a first electric path for the circuit path.
During a first portion of the movement from the closed position to the open position and before electrically disconnecting from the jaws, the blade arm electrically connects to the actuator arm, which is electrically connected to the plunging contactor, to provide a second electric path for the circuit through the plunging contactor in parallel with the first electric path through the jaws. Then, during a second portion of the movement from the closed position to the open position, the blade arm electrically disconnects from the jaws and remains in electrical connection with the actuator arm to connect a series electrical path for circuit through the plunging contact.
In addition, the toggle mechanism is configured, before accelerating the plunging contactor to open the circuit during the opening stroke, to allow the blade arm to move through a sufficient distance to prevent the circuit from arcing between the blade arm and the jaws in response to separation of the first and second contacts. This causes an arc to be drawn and extinguished between the first and second contacts within the sealed interrupter chamber during the opening stroke. In one alternative, after completion of the opening stroke and upon reaching the opposing position, a counter weight connected to the actuator arm causes the actuator arm to automatically return to its initial position. This causes the plunging contactor to moved through the closing stroke to reset the interrupter.
In another alternative, after completion of the opening stroke and before the blade arm reaches the open position, the actuator arm passes through the opposing position, separates from the blade arm, returns to the opposing position, and temporarily remains substantially in the opposing position. Then, as the blade arm subsequently moves from the open position to the closed position, the blade arm electrically connects with and moves the actuator arm from the opposing position to the initial position and thereby triggers the penetrating contact to move through the closing stroke. In this case, the toggle mechanism is configured to accelerate the plunging contactor to close the circuit during the closing stroke before the blade arm to moves to a position that would allow the circuit to arc between the blade arm and the jaws. This causes an arc to be drawn and extinguished between the first and second contacts within the sealed interrupter chamber during the closing stroke.
The blade arm typically pivots about a base during movement between the open and closed positions, and includes a contact area for contacting the jaws when the blade arm is in the closed position. To meet electrical code requirements, the actuator arm is positioned in the opposing position such that the minimum distance between the contact area of the blade arm and the actuator arm is at least as great as the minimum distance between the contact area and the base of the blade arm. In other words, the distance between the actuator arm and the blade arm is at least as great as the distance between the blade arm and the jaws when the blade arm is in the open position (i.e., raised in a typical disconnect switch configuration) and the actuator arm is in the opposing position (i.e., raised in a typical disconnect switch configuration).
In order to provide the required xe2x80x9cdwellxe2x80x9d to allow the actuator arm to trigger as desired on other the opening and closing strokes, the toggle mechanism includes a cam surface positioned between the actuator arm and a linkage mechanically coupling the actuator arm to the plunging contactor by way of the toggle mechanism. The cam surface causes the toggle mechanism to trigger the opening stroke of the plunging contactor as the blade arm moves the actuator arm from the initial position to the opposing position, and also triggers the closing stroke of the plunging contactor as the blade arm moves the actuator arm from the opposing position to the initial position, while maintaining a sufficient distance between the blade arm and the jaws to prevent the circuit from arcing between the blade arm and the jaws.
In yet another alternative, the circuit interrupter includes a voltage-clamping device connected in parallel across the contacts of the interrupter. The voltage-clamping device has a voltage-level threshold that may be selected to prevent a restrike from occurring across the contacts of the interrupter when the interrupter is operated to disconnect a capacitive load from an electric power system. For example, the electric power system may carry an AC voltage defining a maximum voltage of about one per-unit, the capacitive load may be charged to about one per-unit, and the voltage-level threshold for the voltage-clamping device may be selected to be about one per-unit. In this configuration, the parallel-connected voltage-clamping device may operate to discharge the capacitive load while limiting the voltage across the circuit interrupter to the voltage-level threshold, about one per-unit. Thus, the parallel-connected voltage-clamping device prevents restrikes from occurring within the circuit interrupter during capacitor switching, when the voltage across the interrupter would approach two per-unit if the voltage-clamping device was not present, and the two per-unit voltage level exceeds the no-restrike design voltage of the interrupter.
That the invention improves over the drawbacks of prior circuit interrupters and accomplishes the advantages described above will become apparent from the following detailed description of specific embodiments and the appended drawings and claims.

Limited restrike electric power circuit interrupter suitable for use as a line capacitor and load switch


An image reading apparatus has a sensing unit to repeat a scanning on an original image with a predetermined time interval between scans so as to obtain a new set of image information data with each scan, a memory unit to store the image information data and a control unit which commands the memory unit to read the image information stored therein. The memory unit has two memory areas, and each of the two memory areas is alternately updated with each scan for storing a set of the image information data. In response to a read command from the control unit, the memory unit starts to read the image information data from one of the memory areas which is not used for storing at the time the command is issued.

The present invention relates to an image reading apparatus which divides an image on a negative color film into pixels so as to read the image information in the form of digital image information, and which controls the exposure amount properly according to the digital image information or contributes to determine the amount of exposure correction.
In general, a photographic printing apparatus uses an LATD system to control exposure time when a photographic paper is printed from a negative image. In this case, the LATD system is defined as an entire area transmission density control system in which: an amount of light transmitted through a negative film is measured at each color of B, G and R; and from the obtained measurement information, the exposure amount of each color for a photographic paper is controlled to be equal so that a print of appropriate color balance and density level can be provided.
However, the LATD system is based on the following rules of thumb:
(1) A ratio of the average luminance of an entire photographic scene to the luminance of a primary photographic object is statistically constant.
(2) Color balance of B, G and R in a scene is approximately constant, and its average is statistically neutral gray.
Therefore, in the case of a negative film, the luminance distribution and color balance of which are deviated from a statistical average, a desirable print can not be provided.
Therefore, in the highly efficient photographic printing apparatus used at present, an exposure amount is determined in the following manner: a negative image is divided into small pixels; image information characteristic values of each pixel (such as optical transmitting density and/or optical transmitting ratio) are measured; and the exposure amount is determined according to the result of this measurement. Alternatively, according to the result of measurement, the exposure amount determined by the LATD system is appropriately corrected.
The aforesaid apparatus is generally referred to as a scanner. The following 3 kinds of pixel division reading apparatus to read an original image on a negative film can be considered.


The device is a precision motion right angle drive for use with linear and rotary stages which employs a combination of globoid worm and small diameter star gear. Coaxial with the star gear, on the same shaft, is a spur gear which drives the rotary stage gear or a linear rack. The thin star gear achieves meshing accuracy with the globoid worm permitting a large tooth angle for direct preloading without jamming. This gear combination eliminates backlash, allows a low gear ratio for low globoid worm speed, and enables the use of an ordinary spur gear to engage the stage gear without backdrive or backlash. Further, it allows for gear contact area to compensate for the thinness of the star gear. An embodiment including an integrated bearing rotary stage permits flexibility of application and avoidance of need for custom bearing designs by achieving high motion precision at low cost.

Precision positioning stages, both linear and rotary, are used for laboratory and industrial applications including fiber optic and optical alignment systems.
Prior art technologies include means to achieve precision linear or rotational motion using either open-loop or closed-loop methodologies. In the context of right angle drives, of relevance are means that achieve precision motion while converting rotation along one axis into rotation along a second axis, orthogonal to the first. Application to linear output motion, concerns means of converting precise rotation about a first axis into precise translation along a second axis, orthogonal to the first. Various drive systems employed for stage motion include lead screws, recirculating ball screws, worm drives, gearboxes, and flexible shaft couplings. Prime mover actuation means include manual, electric stepper and servo motors, piezoelectric, magnetostrictive, and hydraulic. Subsidiary to these general design considerations, are supporting technologies relevant to the implementation disclosed herein, such as robust bearing designs, globoid worms, and motion encoders (.
Conventional precision motorized rotary stages exhibit a limited diameter clear aperture in comparison to the bearing footprint, with significant surrounding housing bulk, and a large motor assembly (protrusion) in proportion to the stage size (often conventional designs exhibit a motor housing larger than the stage.
What is needed is a compact mechanism that provides precision rotational drive to any size rotational stage with minimal customization; such a mechanism would not exhibit backlash. The problem for rotational stages is making a full line of standard and custom sizes without the prohibitive expense of new custom high precision parts for each variation. The use of such a mechanism to meet these objectives would be advantageous for driving linear stages, as well.
Globoid Worms
Worms are relevant to the present disclosure and more particularly, globoid worms, given features that can be specially adapted to address issues concerning precision motion drives. With respect to globoid worms, among the various names used to denote this type of gear are the following: globoid worm, hourglass worm, wormoid gear, double enveloping gear, enveloping worm, double enveloping worm, double throated worm, double globoid worm, and cone drive.
FIG. 1 depicts the different types of various prior art worms and associated worm wheels, absent depiction of the associated teeth; (a) cylindrical worm and cylindrical worm wheel, (b) cylindrical worm and enveloping worm wheel, (c) enveloping worm and cylindrical worm wheel, and (d) enveloping worm and enveloping worm wheel. The globoid (enveloping) worm is shown in FIGS. 1c and 1d.
Advantages of the globoid worm over a traditional worm comprise increased driving efficiency (6-10% higher on 25:1 ratio) and increased loading capacity (about 30%). The most commonly cited disadvantages concerning conventional implementations of globoid worm drives include higher manufacturing cost and sensitivity of the enveloping pinion to the axial location. In order for the conventional device to be efficient (or turn at all), stage carrier backlash (moving platform relative to stage body) must be introduced. Due to the tooth geometry, the globoid worm can mesh not only with a mating enveloping gear but also with a correctly designed cylindrical helical gear. The substantial thickness of the mating gear is to exploit the heavy load advantage of the globoid worm drive.
There is need to exploit the advantages of the globoid worm for precision motion applications while overcoming the cited disadvantages.

Precision positioning device and stage incorporating a globoid worm and its manufacture


A camless internal combustion engine has electronically or computer controlled, electrically operated hydraulic actuators for selectively opening the engine cylinder valves. The engine is capable of operating in either positive power mode or compression release engine braking mode. The pressure of the hydraulic fluid available for application to the hydraulic actuators is automatically adjusted from a relatively low pressure during positive power mode to a relatively high pressure during compression release engine braking mode. The stroke lengths of the engine cylinder valves may be automatically adjusted for various engine operating conditions using feedback loops that include sensors for detecting the amount of opening of each engine cylinder valve whose stroke length is to be controlled in this manner. The shapes of the valve opening and closing trajectories as a function of engine crank angle may similarly be varied in many other respect.

This invention relates to camless internal combustion engines, and more particularly to providing compression release braking and other enhancements for such engines.
Most conventional internal combustion engines have rotating cams for causing the intake and exhaust valves in the engine cylinders to open and close at the appropriate times relative to reciprocation of the pistons in the cylinders. This type of engine construction has some limitations which have prompted consideration of alternative means for opening the intake and exhaust valves. For example, with cams for opening the cylinder valves it is difficult or impossible to adjust valve timing for different engine operating conditions (e.g., different engine speeds). The engine is therefore typically constructed so that it has optimum valve timing under one set of operating conditions (e.g., at a particular engine speed), thereby leaving valve timing somewhat suboptimal for other operating conditions (e.g., at other engine speeds). The amounts by which the valves open are also difficult or impossible to adjust for various operating conditions of engines with cams. Again, the engine is therefore typically constructed so that it has fixed valve openings which may be better for some engine operating conditions than for other engine operating conditions.
Because of the difficulty or impossibility of adjusting such parameters as valve timing and stroke in conventional internal combustion engines, various "camless" engines have been proposed. For example, Ule U.S. Pat. No. 4,009,695 purports to show engines in which the intake and exhaust valves are opened and closed by hydraulic actuators. The application of hydraulic fluid to these actuators is controlled by electrically operated hydraulic valves.
With many engines it is desirable to have both a positive power mode of operation (in which the engine produces power for such purposes as propelling an associated vehicle) and a braking mode of operation (in which the engine absorbs power for such purposes as slowing down an associated vehicle). As shown, for example, by Cummins U.S. Pat. No. 3,220,392, it is well known that a highly effective way of operating an engine in braking mode is to cut off the fuel supply to the engine and to then open the exhaust valves in the engine near top dead center of the compression strokes of the engine cylinders. This allows air that the engine has compressed in its cylinders to escape to the exhaust system of the engine before the engine can recover the work of compressing that air during the subsequent "power" strokes of the engine pistons. This type of engine braking is known as compression release engine braking.
It takes a great deal more force to open an exhaust valve to produce a compression release event during compression release engine braking than to open either an intake or exhaust valve during positive power mode operation of the engine. During positive power mode operation the intake valves typically open while the piston is moving away from the valves, thereby creating a low pressure condition in the engine cylinder. Thus the only real resistance to intake valve opening is the force of the intake valve return spring which normally holds the intake valve closed. Similarly, during positive power mode operation the exhaust valves typically open near the end of the power strokes of the associated piston after as much work as possible has been extracted from the combustion products in the cylinder. The piston is again moving away from the valves and the cylinder pressure against which the exhaust valves must be opened is again relatively low. (Once opened, the exhaust valves are typically held open throughout the subsequent exhaust stroke of the associated piston, but this only requires enough force to overcome the exhaust valve return spring force.)
During compression release engine braking, however, a much greater force is required to open the exhaust valves to produce a compression release event because such events are produced near top dead center of engine compression strokes when the gas pressure in the engine cylinders is close to a maximum. If the engine is a camless engine of the type in which the valves are opened by hydraulic actuators, very high pressure hydraulic fluid may have to be supplied to ensure that there is sufficient force available to open the exhaust valves during compression release engine braking. For example, the necessary hydraulic fluid pressure may be approximately 3,000-4,000 psi.
It is not a problem or even a disadvantage to provide high pressure hydraulic fluid during engine braking because the more energy the engine absorbs in this operating mode, the more braking it produces. During positive power mode operation, however, it is undesirable for the engine to be required to pump hydraulic fluid to such high pressures because this reduces the power available from the engine for useful, vehicle-propelling work.
In view of the foregoing, it is an object of this invention to improve the performance of camless engines in which the valves are opened hydraulically and which are capable of operating in a compression release engine braking mode as well as in a positive power mode.
It is a more particular object of this invention to avoid wasteful pumping of hydraulic fluid to very high pressures which are not needed during positive power mode operation of a camless engine, even though such high pressure hydraulic fluid may be needed during compression release engine braking mode operation of the engine.
Another characteristic of engine operation which it may be desirable to change when switching from positive power mode to compression release engine braking mode (or even when operating conditions change significantly within either of these two modes of engine operation) is the amount by which some or all of the valves in the engine cylinders open. For example, because exhaust valves open near top dead center of compression strokes of the engine cylinders during compression release engine braking, it may be desirable to reduce the exhaust valve stroke during engine braking to ensure that the exhaust valves do not hit the top of the engine pistons when the exhaust valves are opened. As another example, larger valve openings may be desirable during high speed positive power mode operation of the engine, while smaller valve openings may be preferable at lower speed positive power mode operation. Other changes in valve opening and closing trajectories may be desirable under various engine operating conditions. It may also be important to ensure that each valve returns to its seat without undue impact between the valve and seat.
It is therefore another object of this invention to facilitate modifying the stroke lengths and/or other characteristics of the trajectories of the cylinder valves in camless engines depending on various operating parameters of the engine.
It is still another object of this invention to facilitate reducing the impact between a closing valve and its seat in a camless internal combustion engine.

Camless engines with compression release braking


A fan motor includes a motor, an impeller and a housing. The housing includes an inner wall portion, a silencer portion, and a communicating opening. The inner wall portion extends along a rotation axis to assume a tubular shape, and houses at least a portion of the impeller therein. The silencer portion includes a portion radially outside of the inner wall portion, and defines a silencing space between the inner wall portion and the silencer portion. The communicating opening brings a space inside of the inner wall portion into communication with the silencing space. A portion of the communicating opening is defined by an end portion of the inner wall portion on an inlet side. The silencing space covers only a portion of the circumferential extent of the inner wall portion. This allows the silencing space to be arranged in a dead space around the inner wall portion.

1. Field of the Invention
The present invention relates to a fan motor.
2. Description of the Related Art
Axial fan motors arranged to produce axial air flows by rotating impellers using driving forces of motors have been known. The axial fan motors are, for example, installed in household electrical appliances, office automation appliances, transportation equipment, and so on, and are used for the purposes of cooling electronic components, circulating gases in device cases, and so on. In addition, such fan motors are sometimes used for circulating gases in server rooms in which a large number of electronic devices are installed. A known fan motor is described in, for example, JP-A 2007-218150.
The fan motor described in JP-A 2007-218150 includes a casing defining a wind channel inside thereof, and a rotor fan and a stator housed in the casing. Once this fan motor is driven, a plurality of blades of the rotor fan are caused to rotate to produce an axial air flow in the wind channel.
In recent years, there has been an increasing demand for an increase in efficiency of fan motors. However, if the flow rate of a fan motor is increased in order to improve the efficiency of the fan motor, noise inevitably increases. Accordingly, in recent years, there has been an increasing need for reducing noise of the fan motors. Meanwhile, in recent years, there has been an increasing demand for reducing the size of the fan motors. Therefore, it is not desirable to increase the size of a fan motor in order to achieve reduced noise. Accordingly, there has been a demand for a technique for reducing noise of a fan motor without increasing the size of a space in which the fan motor is installed.
A space in which the known fan motor described in JP-A 2007-218150 is installed is a space which includes flanges and is substantially square when viewed in an axial direction. In this case, spaces extending in the axial direction between the two flanges are dead spaces. That is, this fan motor has dead spaces covering only a part of the circumferential extent thereof. If a reduction in the noise of the fan motor can be achieved by utilizing such dead spaces, the reduction in the noise of the fan motor can be achieved without an increase in the size of the space in which the fan motor is installed.


A device for producing-cropped photographs is made up of separate pieces adapted to be assembled entirely by feel in a darkroom relative to a conventional enlarger for the making of prints from a photographic image projected by the enlarger. The device includes a base sheet and template sheet or sheets having the same shape and outside dimensions as the base sheet. Both the base sheet and the template sheet or sheets are sufficiently thick and stiff to enable proper alignment thereof entirely by feel in a darkroom of the outer peripheries thereof, relative to a sheet of photographic paper interposed therebetween. Multiple template sheets are preferably provided by packaging the device in kit form. In assembling the device in a darkroom, adjustment of the enlarger is usually carried out relative to the base sheet with the room lighted and prior to placement of the unexposed photographic paper, the base sheet being fastened in place on the enlarger stand as by pressure sensitive tape following adjustment of the enlarger. The invention is also concerned with the method of using the device.

1. Field
The invention is in the field of photography, and particularly the darkroom enlarging and printing of photographs.
2. State of the Art
Adjustable cropping devices, usually in the form of so-called "easels" are in general use. As used, the operator places a sheet of photographic paper on the bed of the device in a darkroom and moves adjustably-attached, side pieces over onto the paper to frame a desired opening for receiving the image to be applied to and developed on the paper. The side pieces are arranged to cover edge margins of the paper so as to prevent exposure of those areas. After the image to be printed is projected onto the paper by a conventional enlarger and the operator develops the exposed paper as a photographic print, the resulting image on the print is framed by a white border. Such cropping easels are shown in various brochures and catalogs. They are quite expensive. Moreover, operators have difficulty accurately placing the photographic paper on them in a darkroom. Also, they are delicate and easily damaged. The side members are typically made of thin metal, which are easily bent out of place as well as being subject to damage from developer chemicals used in darkrooms. Such easel cropping devices are intended for professional photographers. Amateurs and photographic students do not usually own an easel and those provided in schools are for use in common by many students and are subject to abuse.


An electrically heatable window pane suitable for use in an anti-icing capacity in an aircraft windshield includes a substantially transparent layer of an electroconductive material, preferably tin oxide, sandwiched between fused sheets of glass. The sheets of glass and the layer of electroconductive material are fused together to form a structurally unitary window pane which is heatable by applying an electric potential to the electroconductive layer. Such a heatable window pane may be laminated to a structural fail-safe glass ply in a conventional manner to form a preferred embodiment of an aircraft windshield. In an alternative embodiment, an airplane windshield is formed with two independent electroconductive layers adjacent the inner and outer surfaces of the windshield to provide anti-icing capability on the outside surface and defogging capability on the inside surface.

The present invention relates to electrically heated windows, and more particularly to electrically heated windshields for aircraft.
Windshields for commercial aircraft are generally laminated structures formed of several layers of tempered glass and polymeric binding materials. Typically, a laminated aircraft windshield includes an outer glass face ply that is electrically heatable to prevent the accumulation of ice thereon. The outer glass face ply is laminated to a thicker, inner glass ply referred to as a main structural ply or pressure pane. Sometimes an additional structural ply, known as a fail-safe pane, is provided. The glass plies are typically bonded together with a clear polymeric sheet known as an interlayer. In addition to binding the glass plies together, the interlayer provides a flexible membrane to contain internal cabin pressure in the unlikely event of a complete glass pane failure.
In one type of heated aircraft windshield known in the industry, an electrical heating element consists of a thin layer of a transparent electroconductive material fused to the inner surface of the glass face ply. The face ply is bonded to a main structural glass ply by a polymeric interlayer as described above. The layer of electroconductive material is thus fused to the glass face ply on one side and adhered to the interlayer on the opposite side. The glass face ply is heated by passing an electric current across the windshield through the electroconductive layer. Electrical contact with the electroconductive layer is typically made with a pair of bus bars inserted between the glass face ply and the interlayer along opposite sides of the windshield. One advantage of such a windshield is that heat may be generated as a result of the electrical resistance of the electroconductive coating to maintain the temperature of the outer surface sufficiently high to prevent formation of ice or frost. Also, the absence of wire or other types of opaque heating elements embedded in the windshield improves the optical quality of the windshield.
Despite the advantages of the above-described windshield, certain disadvantages have been recognized. For example, the wide temperature range to which aircraft windshields are exposed during normal flight operations results in differential expansion of the polymeric interlayer and the glass plies. The interlayer has a higher coefficient of thermal expansion than that of either the glass face ply or the glass structural ply. Hence, the interlayer tends to expand and contract to a greater extent than the glass plies during temperature fluctuations, thereby resulting in substantial shear stresses being imposed on the bond between the glass plies. It has been observed that such shear stresses imposed by temperature fluctuations are particularly pronounced at the margins of the windshield. Additionally, various orthogonal stresses are imposed on the glass plies and the interlayer by the pressure differential between the pressurized aircraft cabin and the reduced pressure of the outside atmosphere. The various stresses imposed by thermal fluctuations and pressure differentials lead to three principal modes of failure of such windshields. First, bond failure, or delamination, occasionally occurs btween the glass plies and the interlayer. This results in deterioration of the optical quality of the windshield and also occasionally results in disruption and failure of portions of the electroconductive heating element.
Secondly, a phenomenon known in the industry as "cold chipping" is occasionally observed along the margins of the windshield where shear stresses are most pronounced. Cold chipping occurs when the interlayer thermally contracts due to cold temperatures and pulls chips of glass inwardly away from the edges of the outer glass face ply. Occasionally, these chips are deep enough to penetrate that portion of the glass that is subject to locked-in tension stresses caused by tempering, resulting in complete fracturing of the face ply.
Thirdly, a condition also due to the thermal contraction and stiffening of the interlayer is known as interlayer or vinyl cracking. This occurs when the resulting high stresses are not relieved by delamination or cold chipping, and is essentially a tensile or cohesive failure of the interlayer. This results in a loss of the ability to carry fail-safe pressure loads in the event of glass failure.
It is also recognized that the deterioration of aircraft windshields in the manner described above may be aggravated and accelerated by exposure of the polymeric resin constituting the interlayer to ultraviolet radiation and moisture, particularly around the edges of the windshield. Such exposure may cause the interlayer resin to deteriorate and become relatively hard and brittle. The brittle resin is thus less plastic and causes greater stresses to be applied to the bond line, the glass plies and the interlayer itself upon thermal contraction and expansion of the resin.
Yet another problem with conventional electrically heated windshields is the occasional fracturing of the outer face ply by hail. This occurs because the face ply must be kept sufficiently thin so that the electroconductive heating element may be positioned sufficiently close to the outer exposed surface to provide effective anti-icing capabilities. The strength of a glass ply may be increased by a thermal or chemical process known as tempering. The increase in strength that is obtainable is proportional to the thickness of the ply and has a marked effect on the fracture characteristics and residual visibility through the windshield in the event of impact damage. To ensure sufficient residual visibility, face plies are usually only partially tempered. As a result, and also because of the reduced thickness demanded by thermal requirements, face plies are not as strong as would be desired to effectively withstand all hail conditions.
Accordingly, it is a general object of the present invention to provide an improved electrically heated window suitable for use as an aircraft windshield. Specifically, it is an object of the present invention to provide an electrically heated aircraft windshield having a heatable main glass ply of unitary construction. It is also an object of the present invention to reduce the use of interlayers in electrically heated aircraft windshields. Finally, it is yet another object of the present invention to provide a heatable aircraft windshield that can be fabricated with a greater degree of strength for increased impact and abrasion resistance and improved durability.


A nut includes a bottom wall adapted to be connected fixedly to a printed circuit board, and an annular surrounding wall extending integrally from a periphery of the bottom wall away from the printed circuit board, having a threaded inner wall surface, and cooperating with the bottom wall to define a threaded blind hole for engagement with a bolt.

1. Field of the Invention
The invention relates to a nut, more particularly to a nut with a threaded blind hole for use on a printed circuit board.
2. Description of the Related Art
Currently, to solder circuit-related components on a printed circuit board (PCB), each component is sucked by a suction nozzle first, and is then released to a predetermined position on the PCB. After all the components are mounted on the PCB, the latter is heated by passing through a soldering furnace, thereby soldering all components on the PCB.
Referring to FIG. 1, a conventional nut 3 includes an annular surrounding wall 31 and a through hole 32 defined by the annular surrounding wall 31. Since a suction nozzle 5 cannot apply a negative pressure to the nut 3 due to the presence of the through hole 32, a soft top plug 33 has to be mounted on a top surface 34 of the nut 3. The top plug 33 includes a head portion 332, and a shank portion 331 that extends into the through hole 32 and that has an outside diameter slightly larger than the inner diameter of the through hole 32 such that the shank portion 331 forms an air-tight seal with the through hole 32, thereby sealing the through hole 32.
During assembly, the suction nozzle 5 applies a negative pressure to the head portion 332 of the plug 33 so as to hold the nut 3, and subsequently releases the nut 3 to a predetermined position on the PCB 4. The PCB 4 is then passed through a soldering furnace (not shown) so that the nut 3 and the other components are soldered on the PCB 4. The plug 33 is removed after assembly. When an automated arm (not shown) is used to remove the plug 33 from the nut 3, it is likely that the connection between the nut 3 and the circuit board 4 is damaged. As such, manual removal is needed.
Referring to FIG. 2, a cap 33′ can be mounted on the top surface of the nut 3 instead of the plug 33 (see FIG. 1) to cover the through hole 32. The cap 33′ has a clamp portion 331′ with an inner diameter slightly smaller than the outer diameter of the nut 3, such that the clamp portion 331′ can be sleeved tightly on the surrounding wall 31 of the nut 3. The cap 3′ is also manually removed from the nut 3 after the nut 3 is soldered on the PCB 4.
Since the through hole 32 in the conventional nut 3 has to be covered by the plug 331 or the cap 331′ before soldering on the PCB 4, and since the plug 331 or the cap 331′ has to be manually removed after soldering on the PCB 4, the assembly steps and the assembly cost for mounting the conventional nut 3 on the PCB 4 are increased.


An apparatus and method for hydrating is provided for hydrating a lens and extracting residual materials from the lens. The apparatus includes a shaft; multiple arms extending radially from a lower end of the shaft about a central axis in a star-shaped pattern, each arm including a fin extending therebelow such that multiple fins also extend radially with respect to said central axis, wherein the fins including lower outer edges that converge and form a nozzle face. A fluid transport passage extends through the shaft and terminates at an opening in the nozzle face, whereby fluid can be evacuated from the lens through this passage. Preferably, at least one recessed channel is formed in the nozzle face where the fins converge, wherein each of these channels extends from the opening in the nozzle face that forms a terminus of the fluid transport passage to a space between two adjacent fins. The lower outer edges of the fins have an arcuate surface, the arcuate surfaces forming a convex-shaped nozzle face. Preferably, the outer tips of the arms extend radially from the central axis of the apparatus further than the fins extend.

This invention relates to an apparatus for hydrating and extracting residual materials from a lens, especially a contact lens, and methods employing the apparatus.
Soft, hydrogel contact lenses are produced by polymerizing a monomeric mixture comprising a hydrophilic monomer and a crosslinking agent. The monomeric mixture can be cast directly into lenses by static cast molding or spincasting methods, where the liquid monomeric mixture is charged to the mold and is then cured, typically by subjecting the monomeric mixture to UV radiation, heat or both. Alternately, the monomeric mixture can first be cured in the form of cylindrical blanks (also referred to in the art as "buttons"), which buttons are then lathe cut into lenses, or buttons can be cut from rods or sheet of cured lens material for lathe cutting into lenses.
Regardless of the manner of forming the lens, following polymerization (or curing) of the monomeric mixture such soft lenses are typically hydrated by exposure to water or an aqueous solution under appropriate conditions that the lens-shaped article absorbs and retains water to form a hydrogel. Also, the lenses are typically treated to extract undesired residual materials remaining in the lens from the polymerization process. Such extractibles may include incompletely polymerized monomers, oligomers formed from the curing process, and any diluent or solvent present in the initial monomeric mixture. The extraction may be performed as a process step separate from the hydration process, or these two processes may be performed simultaneously.
As an example, U.S. Pat. No. 5,271,875 discloses a method of static cast molding lenses in a mold assembly composed of anterior and posterior mold sections. The method includes introducing monomeric mixture to the mold assembly, curing the monomeric mixture to form a lens, and recovering the lens and hydrating the lens to form a soft hydrogel lens. U.S. Pat. No. 5,271,875 illustrates two general methods of recovering the lens from the mold and hydrating the lens. First, in a "wet release" process, the lens is hydrated while retained in a mold section, the hydration process also facilitating removal of the lens from the mold section in which it is retained. Second, in a "dry release" process, the lens is first disengaged from the mold section in which it is retained by a force applied by a mechanical fixture, whereby the lens is hydrated after removal from the mold. U.S. Pat. No. 5,264,161 also discloses a "wet release" method of recovering a lens, where a contact lens and the mold in which it is retained are added to an aqueous bath including a surfactant.