The invention pertains to the field of computer directed instruments for performing the polymerase chain reaction (hereinafter PCR). More particularly, the invention pertains to automated instruments that can perform the polymerase chain reaction simultaneously on many samples with a very high degree of precision as to results obtained for each sample. This high precision provides the capability, among other things, of performing so-called "quantitative PCR".
To amplify DNA (Deoxyribose Nucleic Acid) using the PCR process, it is necessary to cycle a specially constituted liquid reaction mixture through a PCR protocol including several different temperature incubation periods. The reaction mixture is comprised of various components such as the DNA to be amplified and at least two primers selected in a predetermined way to as to be sufficiently complementary to the sample DNA as to be able to create extension products of the DNA to be amplified. The reaction mixture includes various enzymes and/or other reagents, as well as several deoxyribonucleoside triphosphates such as dATP, dCTP, dGTP and dTTP. Generally, the primers are oligonucleotides which are capable of acting as a point of initiation of synthesis when placed under conditions in which synthesis of a primer extension product which is complimentary to a nucleic acid strand is induced, i.e., in the presence of nucleotides and inducing agents such as thermostable DNA polymerase at a suitable temperature and pH.
The Polymerase Chain Reaction (PCR) has proven a phenomenally successful technology for genetic analysis, largely because it is so simple and requires relatively low cost instrumentation. A key to PCR is the concept of thermocycling: alternating steps of melting DNA, annealing short primers to the resulting single strands, and extending those primers to make new copies of double stranded DNA. In thermocycling, the PCR reaction mixture is repeatedly cycled from high temperatures (>90.degree. C.) for melting the DNA, to lower temperatures (40.degree. C. to 70.degree. C.) for primer annealing and extension. The first commercial system for performing the thermal cycling required in the polymerase chain reaction, the Perkin-Elmer Cetus DNA Thermal Cycler, was introduced in 1987.
Applications of PCR technology are now moving from basic research to applications in which large numbers of similar amplifications are routinely run. These areas include diagnostic research, biopharmaceutical development, genetic analysis, and environmental testing. Users in these areas would benefit from a high performance PCR system that would provide the user with high throughput, rapid turn-around time, and reproducible results. Users in these areas must be assured of reproducibility from sample-to-sample, run-to-run, lab-to-lab, and instrument-to-instrument.
For example, the physical mapping process in the Human Genome Project may become greatly simplified by utilizing sequence tagged sites. An STS is a short, unique sequence easily amplified by PCR and which identifies a location on the chromosome. Checking for such sites to make genome maps requires amplifying large numbers of samples in a short time with protocols which can be reproducibly run throughout the world.
As the number of PCR samples increases, it becomes more important to integrate amplification with sample preparation and post-amplification analysis. The sample vessels must not only allow rapid thermal cycling but also permit more automated handling for operations such as solvent extractions and centrifugation. The vessels should work consistently at low volumes, to reduce reagent costs.
Generally PCR temperature cycling involves at least two incubations at different temperatures. One of these incubations is for primer hybridization and a catalyzed primer extension reaction. The other incubation is for denaturation, i.e., separation of the double stranded extension products into single strand templates for use in the next hybridization and extension incubation interval. The details of the polymerase chain reaction, the temperature cycling and reaction conditions necessary for PCR as well as the various reagents and enzymes necessary to perform the reaction are described in U.S. Pat. Nos. 4,683,202, 4,683,195, EPO Publication 258,017 and 4,889,818 (Taq polymerase enzyme patent), which are hereby incorporated by reference.
The purpose of a polymerase chain reaction is to manufacture a large volume of DNA which is identical to an initially supplied small volume of "seed" DNA. The reaction involves copying the strands of the DNA and then using the copies to generate other copies in subsequent cycles. Under ideal conditions, each cycle will double the amount of DNA present thereby resulting in a geometric progression in the volume of copies of the "target" or "seed" DNA strands present in the reaction mixture.
A typical PCR temperature cycle requires that the reaction mixture be held accurately at each incubation temperature for a prescribed time and that the identical cycle or a similar cycle be repeated many times. A typical PCR program starts at a sample temperature of 94.degree. C. held for 30 seconds to denature the reaction mixture. Then, the temperature of the reaction mixture is lowered to 37.degree. C. and held for one minute to permit primer hybridization. Next, the temperature of the reaction mixture is raised to a temperature in the range from 50.degree. C. to 72.degree. C. where it is held for two minutes to promote the synthesis of extension products. This completes one cycle. The next PCR cycle then starts by raising the temperature of the reaction mixture to 94.degree. C. again for strand separation of the extension products formed in the previous cycle (denaturation). Typically, the cycle is repeated 25 to 30 times.
Generally, it is desirable to change the sample temperature to the next temperature in the cycle as rapidly as possible for several reasons. First, the chemical reaction has an optimum temperature for each of its stages. Thus, less time spent at nonoptimum temperatures means a better chemical result is achieved. Another reason is that a minimum time for holding the reaction mixture at each incubation temperature is required after each said incubation temperature is reached. These minimum incubation times establish the "floor" or minimum time it takes to complete a cycle. Any time transitioning between sample incubation temperatures is time which is added to this minimum cycle time. Since the number of cycles is fairly large, this additional time unnecessarily lengthens the total time needed to complete the amplification.
In some prior automated PCR instruments, the reaction mixture was stored in a disposable plastic tube which is closed with a cap. A typical sample volume for such tubes was approximately 100 microliters. Typically, such instruments used many such tubes filled with sample DNA and reaction mixture inserted into holes called sample wells in a metal block. To perform the PCR process, the temperature of the metal block was controlled according to prescribed temperatures and times specified by the user in a PCR protocol file. A computer and associated electronics then controlled the temperature of the metal block in accordance with the user supplied data in the PCR protocol file defining the times, temperatures and number of cycles, etc. As the metal block changed temperature, the samples in the various tubes followed with similar changes in temperature. However, in these prior art instruments not all samples experienced exactly the same temperature cycle. In these prior art PCR instruments, errors in sample temperature were generated by nonuniformity of temperature from place to place within the metal sample block, i.e., temperature gradients existed within the metal of the block thereby causing some samples to have different temperatures than other samples at particular times in the cycle. Further, there were delays in transferring heat from the sample block to the sample, but the delays were not the same for all samples. To perform the PCR process successfully and efficiently, and to enable so called "quantitative" PCR, these time delays and temperature errors must be minimized to a great extent.
The problems of minimizing time delays for heat transfer to and from the sample liquid and minimizing temperature errors due to temperature gradients or nonuniformity in temperature at various points on the metal block become particularly acute when the size of the region containing samples becomes large. It is a highly desirable attribute for a PCR instrument to have a metal block which is large enough to accommodate 96 sample tubes arranged in the format of an industry standard microtiter plate.
The microtiter plate is a widely used means for handling, processing and analyzing large numbers of small samples in the biochemistry and biotechnology fields. Typically, a microtiter plate is a tray which is 35/8 inches wide and 5 inches long and contains 96 identical sample wells in an 8 well by 12 well rectangular array on 9 millimeter centers. Although microtiter plates are available in a wide variety of materials, shapes and volumes of the sample wells, which are optimized for many different uses, all microtiter plates have the same overall outside dimensions and the same 8.times.12 array of wells on 9 millimeter centers. A wide variety of equipment is available for automating the handling, processing and analyzing of samples in this standard microtiter plate format.
Generally microtiter plates are made of injection molded or vacuum formed plastic and are inexpensive and considered disposable. Disposability is a highly desirable characteristic because of the legal liability arising out of cross contamination and the difficulty of washing and drying microtiter plates after use.
It is therefore a highly desirable characteristic for a PCR instrument to be able to perform the PCR reaction on up to 96 samples simultaneously said samples being arranged in a microtiter plate format.
Of course, the size of the metal block which is necessary to heat and cool 96 samples in an 8.times.12 well array on 9 millimeter centers is fairly large. This large area block creates multiple challenging engineering problems for the design of a PCR instrument which is capable of heating and cooling such a block very rapidly in a temperature range generally from 0 to 100.degree. C. with very little tolerance for temperature variations between samples. These problems arise from several sources. First, the large thermal mass of the block makes it difficult to move the block temperature up and down in the operating range with great rapidity. Second, the need to attach the block to various external devices such as manifolds for supply and withdrawal of cooling liquid, block support attachment points, and associated other peripheral equipment creates the potential for temperature gradients to exist across the block which exceed tolerable limits.
There are also numerous other conflicts between the requirements in the design of a thermal cycling system for automated performance of the PCR reaction or other reactions requiring rapid, accurate temperature cycling of a large number of samples. For example, to change the temperature of a metal block rapidly, a large amount of heat must be added to, or removed from the sample block in a short period of time. Heat can be added from electrical resistance heaters or by flowing a heated fluid in contact with the block. Heat can be removed rapidly by flowing a chilled fluid in contact with the block. However, it is seemingly impossible to add or remove large amounts of heat rapidly in a metal block by these means without causing large differences in temperature from place to place in the block thereby forming temperature gradients which can result in nonuniformity of temperature among the samples.
Even after the process of addition or removal of heat is terminated, temperature gradients can persist for a time roughly proportional to the square of the distance that the heat stored in various points in the block must travel to cooler regions to eliminate the temperature gradient. Thus, as a metal block is made larger to accommodate more samples, the time it takes for temperature gradients existing in the block to decay after a temperature change causes temperature gradients which extend across the largest dimensions of the block can become markedly longer. This makes it increasingly difficult to cycle the temperature of the sample block rapidly while maintaining accurate temperature uniformity among all the samples.
Because of the time required for temperature gradients to dissipate, an important need has arisen in the design of a high performance PCR instrument to prevent the creation of temperature gradients that extend over large distances in the block. Another need is to avoid, as much as possible, the requirement for heat to travel across mechanical boundaries between metal parts or other peripheral equipment attached to the block. It is difficult to join metal parts in a way that insures uniformly high thermal conductance everywhere across the joint. Nonuniformities of thermal conductance will generate unwanted temperature gradients.


It is known to provide play sets for use with reduced scale (e.g., 1/64 Hot Wheels® and Matchbox) toy vehicles. Conventional scaled toy vehicle play sets are not well-suited for use by a child while riding in a vehicle such as a car. They are usually too large to set up and use in a car or other vehicle and often lack structure to secure toy vehicles and other loose pieces of the play set during travel. It is believed that a toy vehicle play set adapted for use by a child riding in a vehicle and that can secure its components would be desirable.


1. Field of the Invention
The present invention relates generally to processes for ensuring an importer's compliance with domestic customs requirements. More specifically, the invention relates to systems and methods for correcting erroneous information reported to customs agents, as well as the effects of such erroneous reports, after the imported goods to which the reported information refer are received by the importer.
2. Description of Related Art
When a company imports goods from foreign sources, the company is subject to numerous U.S. Customs regulations. One set of requirements is based upon a complex classification system created by U.S. Customs, known as the Harmonized Tariff Schedule (HTS) code. Within this system, U.S. Customs classifies types of products using 10-digit HTS codes. These codes are used, for example, in determining the applicable tariff rates on different types of products imported into the U.S. An company importing goods must correctly classify imported products under the HTS code. This task is especially difficult for companies that import a large variety of products, such as automobile parts, because of numerous complexities in the classification system.
Large importers of foreign goods often employ customs brokers to serve as agents between the importer and U.S. Customs. Brokers fulfill a number of duties related to ensuring the importer's compliance with customs rules, including gathering and delivering information regarding imported goods to customs agents. One such duty is classification of goods under the HTS code. A customs broker working for the importer traditionally classifies imported products by assigning what he decides are the appropriate HTS Codes. The broker also assigns what are known as “attribute classifications,” meaning classifications of other relevant attributes, such as classifications relating to NAFTA Certificates, anti-dumping and Department of Transportation specifications. In addition, a large number of parties may be involved in the importation process. For example, the importer may be working with a large number of foreign manufacturers or suppliers. Each imported item, from every manufacturer and every supplier, must be accounted for within the HTS classification system. In the case of an imported automobile, whose parts may originate from a variety of different overseas sources, vendors and suppliers, providing HTS classification for each part and each component is a daunting and difficult task, with many inherent complexities.
Once assigned, the customs broker reports classifications to U.S. Customs and pays duties on behalf of the company based on the reported classifications. Unfortunately, the information reported to U.S. Customs by the customs broker sometimes fails to conform to the actual facts surrounding the goods imported. For example, a broker may not be able to discern precisely how many parts are contained in a carton, or may be unable to accurately classify certain automobile parts that do not clearly fall within one of the Customs-defined HTS codes. For example, an automobile typically includes a transmission system which, in turn, includes a variety of individual components. Each of these components may need to be assigned an HTS code when the transmission system is imported. Assigning and tracking individual HTS codes manually is an extremely complicated and difficult task, particularly for major corporations involved in significant import or export activity. Also, classification codes assigned by a corporation, which a broker may then use to classify imported goods, may be initially incorrect in the corporation's records. This may occur, for example, because of subsequent information received from third parties relating to a particular part. Information obtained from various entities within the importation process, recent U.S. Customs Rulings, and the like may bear on whether initial classifications established by corporate analysts were correct in the first instance or have been modified subsequent to their establishment. Because of these and other complexities in the classification process, such subsequent information often gets lost or overlooked.
Moreover, complications can be inherent to the import process itself. At least four distinct phases of operation may exist as part of this process—namely, (i) a pre-entry or classification process, (ii) an entry process, (iii) a post-entry process (including audits and payment balancing), and (iv) an amendment process. Each such phase often includes a complicated set of procedures, many of which are dependent upon or interrelated to other procedures. The phases also usually include a complex set of data concerning importation procedures, which data may contain many other relevant dependencies and interrelationships. These procedures and interrelationships must often be integrated and managed in a meaningful way so as to ensure full compliance with U.S. import regulations.
Managing and communicating necessary information to and from an importer and a customs broker can also be important. Customs brokers may be appointed by the importer to prepare the necessary paperwork for a given shipment or set of shipments, such as a U.S. Customs 7501 form, a commercial invoice, and a shipment manifest and to present those forms to U.S. Customs when the goods are imported into the country. Customs brokers may also tender tariff payments to U.S. Customs, and are subsequently reimbursed by the importer. The reimbursement process is often slow because of its cumbersome nature. Typically, reimbursement requests or invoices are submitted by the broker to the importer, who must then enter data from the broker's request into a computerized system. Then a process of invoice balancing, reimbursement approval and generating payment for the broker begins. Each step of this process may require a different person or different data, and there is no centralized system for providing the data or access to multiple persons or entities.
Because of the difficulties described above, and other complexities involved in the classification, reporting and customs broker reimbursement process, broker reimbursement may be unduly cumbersome and time consuming.


1. Field of the Invention
The present invention relates to a wire harness-fixing clamp for holding a wire harness comprising wires or a cable, and more particularly to such a clamp suited for holding a self-supporting-type communication cable called xe2x80x9ca hanger gourd-shaped cablexe2x80x9d.
The present application is based on Japanese Patent Application No. Hei. 11-233535, which is incorporated herein by reference.
2. Description of the Related Art
FIG. 3 is a cross-sectional view showing a self-supporting-type cable 1 (called xe2x80x9ca hanger gourd-shaped cablexe2x80x9d) which is a kind of communication cable.
The self-supporting-type cable 1, having the illustrated configuration, includes a cable body portion 2, and a support wire portion 3 integrally formed with the cable body portion 2. Such self-supporting-type cables have various characteristics, and therefore have been extensively used in accordance with the purpose of use and a place where it is used. The cable body portion 2 comprises a conductor (cable core) 2a, an insulating layer 2b formed on the conductor 2a to cover the same, and a protective sheath 4 formed on the insulating layer 2b to cover the same. The support wire portion 3 comprises a support wire 3a, and the sheath 4 formed on the support wire 3a to cover the same, so that the support wire portion 3 is integrally connected to the cable body portion 2. The cable body portion 2 and the support wire portion 3 are interconnected by a sheath connection portion 4a at the boundary between the two portions 2 and 3.
In the installation of the self-supporting-type cable 1 of the above configuration, this cable is often fixed by clip-type clamps at suitable portions thereof spaced along the entire length thereof. One example of such clamps is a wire harness clamp disclosed in Unexamined Japanese Utility Model Publication No. Sho. 63-179717.
This clamp 5, shown in FIGS. 4A and 4B, includes a pair of left and right elastic holding portions 5a and 5b extending upwardly from a clamp body molded of a resin, and a holding recess 5c of an upwardly-open U-shape (in the drawings) is formed between the two elastic holding portions 5a and 5b. A retaining projection 5d is formed at an upper end of one of the elastic holding portions 5a, and bulges to be exposed to the holding recess 5c.
When installing the self-supporting-type cable 1, this cable 1 is fixed to a mounting panel or the like at suitable portions thereof by the use of the clamps 5. More specifically, when the clamp 5 is mounted in an upwardly-directed posture as shown in FIG. 4A, the self-supporting-type cable 1 is usually fitted into the holding recess 5c, with the support wire portion 3 directed downwardly, so that the cable body portion 2 is disposed at a level above the support wire portion 3. The cable body portion 2, thus disposed at the higher level, is held between the left and right elastic holding portions 5a and 5b, and is retained by the elastic force of the resin, and the retaining projection 5d is press-contacted with the cable body portion 2 to prevent the same from withdrawal from the holding recess 5c.
When the self-supporting-type cable 1 is set in an inverted posture in the related clip-type clamp 5 as shown in FIG. 4B, there is encountered the following disadvantage. More specifically, when the self-supporting-type cable 1 is attached to the clamp 5 in such a manner that the cable body portion 2 is directed downwardly, and is first fitted into the holding recess 5c, the support wire portion 3 projects outwardly from the clamp 5, so that the fixing of the cable is unstable. As a result, in use, the cable can flutter to produce noises, and in the worst case, the self-supporting-type cable is disengaged from the clamp 5.
It is therefore an object of the present invention to provide a wire harness-fixing clamp particularly best suited for holding a self-supporting-type communication cable (called xe2x80x9ca hanger gourd-shaped cable) among wire harnesses in a stable condition.
To achieve the above object, according to the first aspect of the present invention, there is provided a wire harness-fixing clamp which comprises a clamp body, a pair of elastic holding portions extending from the clamp body, the elastic holding portions being opposed to each other to form therebetween a holding recess, into which a wire is insertable, and which is operative to hold the wire, and a plurality of retaining projections formed respectively on the elastic holding portions to project into the holding recess, wherein when the wire is inserted into the holding recess, at least one of the retaining projections is operative to retain the wire in the holding recess. When the wire is held in the holding recess, the retaining projections are operative to engage the wire from such a direction as to prevent withdrawal of the wire from the holding recess. The retaining projections may be formed in a bulged manner respectively on inner surfaces of the elastic holding portions.
In the related art, the retaining projection is formed on only one of the elastic holding portions, and therefore there were occasions when the fixing of the wire harness was unstable. In the above construction of the present invention, however, the retaining projections are formed on the opposed elastic holding portions, respectively, and therefore even when the wire harness is set in any posture, the clamp can hold the wire harness in a stable manner.
According to the second aspect of the present invention, the wire may include a body portion, a connection portion, and a support wire portion connected to the body portion through the connection portion. In this case, when the wire is inserted into the holding recess so that the support wire portion is first introduced into the holding recess, the body portion is engaged with the retaining projections to be prevented from withdrawal from the holding recess. Further, when the wire is inserted into the holding recess so that the body portion is first introduced and pressed into the holding recess, the body portion is engaged with one of the retaining projections and a bottom of the holding recess. The wire may be a self-supporting-type cable having a hanger gourd-shape.
Accordingly, even when the wire is set in a proper posture or an inverted posture, with the support wire portion or the body portion first introduced into the holding recess, the body portion is positively held in a press-contacted manner, and therefore the self-supporting-type cable is positively held in a stable condition.
According to the third aspect of the present invention, it is preferable that the retaining projections are offset from each other in a longitudinal direction of the holding recess. More specifically, one of the retaining projections may be formed on an intermediate portion of one of the elastic holding portions, and the other one of the retaining projections may be formed on a distal end portion of the other one of the elastic holding portions. In this case, the retaining projections press-contact with the body portion of the wire, or the one of the retaining projections and the bottom of the holding recess press-contact with the body portion of the wire.
That is, the retaining projections are formed on the suitable portions of the opposed elastic holding portions, respectively. More specifically, the one retaining projection is formed on one of the two elastic holding portions intermediate the opposite ends thereof, whereas the other retaining projection is formed on the distal end portion of the other elastic holding portion. With this construction, the body portion is held between the two retaining projections, and are press-contacted with these retaining projections to be prevented from withdrawal from the holding recess. Alternatively, the body portion is held between the one retaining projection and the bottom of the holding recess in a press-contacted manner, and therefore is stably held against withdrawal from the holding recess.


In many memory devices, including random access memory (RAM) devices, data is typically accessed by supplying an address to an array of memory cells and then reading data from the memory cells that reside at the supplied address. However, in content addressable memory (CAM) devices, data within a CAM array is not accessed by initially supplying an address, but rather by initially applying data (e.g., search words) to the array and then performing a search operation to identify one or more entries within the CAM array that contain data equivalent to the applied data and thereby represent a “match” condition. In this manner, data is accessed according to its content rather than its address. Upon completion of the search operation, the identified location(s) containing the equivalent data is typically encoded to provide an address (e.g., block address+row address within a block) at which the matching entry is located. If multiple matching entries are identified in response to the search operation, then local priority encoding operations may be performed to identify a location of a best or highest priority matching entry. Such priority encoding operations frequently utilize the relative physical locations of multiple matching entries within the CAM array to identify a highest priority matching entry. An exemplary CAM device that utilizes a priority encoder to identify a highest priority matching entry is disclosed in commonly assigned U.S. Pat. No. 6,370,613 to Diede et al., entitled “Content Addressable Memory with Longest Match Detect,” the disclosure of which is hereby incorporated herein by reference. Additional CAM devices are described in U.S. Pat. Nos. 5,706,224, 5,852,569 and 5,964,857 to Srinivasan et al. and in U.S. Pat. Nos. 6,101,116, 6,256,216 and 6,128,207 to Lien et al., the disclosures of which are hereby incorporated herein by reference.
CAM cells are frequently configured as binary CAM cells that store only data bits (as “1” or “0” logic values) or as ternary CAM cells that store data bits and mask bits. As will be understood by those skilled in the art, when a mask bit within a ternary CAM cell is inactive (e.g., set to a logic 1 value), the ternary CAM cell may operate as a conventional binary CAM cell storing an “unmasked” data bit. When the mask bit is active (e.g., set to a logic 0 value), the ternary CAM cell is treated as storing a “don't care” (X) value, which means that all compare operations performed on the actively masked ternary CAM cell will result in a cell match condition. Thus, if a logic 0 data bit is applied to a ternary CAM cell storing an active mask bit and a logic 1 data bit, the compare operation will indicate a cell match condition. A cell match condition will also be indicated if a logic 1 data bit is applied to a ternary CAM cell storing an active mask bit and a logic 0 data bit. Accordingly, if a data word of length N, where N is an integer, is applied to a ternary CAM array having a plurality of entries therein of logical width N, then a compare operation will yield one or more match conditions whenever all the unmasked data bits of an entry in the ternary CAM array are identical to the corresponding data bits of the applied search word. This means that if the applied search word equals {1011}, the following entries will result in a match condition in a CAM comprising ternary CAM cells: {1011}, {X011}, {1X11}, {10X1}, {101X}, {XX11}, {1XX1}, . . . , {1XXX}, {XXXX}.
Applications using CAM devices include database management, disk caching, pattern and image recognition and artificial intelligence. CAM devices are also well suited for use in routing network traffic, such as in network address lookup or packet switching. A network switch comprising a CAM device having entries therein arranged in sectors is illustrated as FIG. 1 of U.S. application Ser. No. 09/962,737, entitled “Content Addressable Memory (CAM) Devices That Can Identify Highest Priority Matches in Non-Sectored CAM Arrays and Methods of Operating Same, filed Sep. 25, 2001, the disclosure of which is hereby incorporated herein by reference. Each of the illustrated sectors is organized to contain only entries having the same number of actively masked bits, with the number of masked bits identifying entries of same priority.
FIG. 1 herein illustrates a conventional CAM device having a plurality of CAM arrays therein arranged in a plurality of rows and columns. The CAM arrays in the first, second, third and fourth rows are illustrated as CAM00–CAM07, CAM10–CAM17, CAM20–CAM27 and CAM30–CAM37. A respective row priority encoder is also provided between each pair of CAM arrays. Thus, as illustrated, the CAM device of FIG. 1 includes sixteen (16) row priority encoders (shown as Row Priority Encoder00-Row Priority Encoder33). These row priority encoders perform final encoding of all match information generated by a respective pair of CAM arrays. A respective global word line decoder is also provided for each row of CAM arrays. As will be understood by those skilled in the art, each global word line decoder provides word line signals on global word lines to the CAM arrays of a respective row during reading and writing operations. Unfortunately, the CAM device of FIG. 1 may not achieve sufficiently high integration or sufficiently low power consumption because each of the row priority encoders typically consumes substantial chip area and requires substantial duplication of circuitry. Moreover, the pitch between global word lines that span across each row of CAM arrays may not be sufficiently large to achieve high yield and reliability when CAM arrays having many rows of normal and redundant CAM cells are utilized.
U.S. Pat. No. 6,307,767 to Fuh also discloses a CAM device having a plurality of CAM arrays therein that are electrically coupled to a central priority encoder. In particular, FIG. 3 of the '767 patent illustrates a prior art CAM device having a central priority encoder 120 that receives match control signals from multiple CAM arrays 101–116 during a lookup operation and then, in response, generates an output address of a highest priority matching entry. FIG. 4 of the '767 patent discloses a CAM system having a plurality of CAM arrays therein that are assigned different priority levels. Circuitry is provided for identifying which of the plurality of CAM arrays has one or more matching entries of highest priority and then latching match control signals from the identified CAM array. These latched signals are provided to a respective priority encoder, which generates a respective address of a highest priority matching entry in the identified CAM array.


1. Field of the Invention
This invention relates to electronic circuits, and more particularly, to methods and mechanisms to record and/or compensate for the aging of the electronic circuits.
2. Description of the Related Art
Over the life an electronic circuit, the effects of aging may have an impact on its operation. Factors such as operating time, voltage, and temperature may change one or more characteristics of various circuit elements. For example, the threshold voltage of a transistor may change over the operating life of an integrated circuit (IC) in which it is implemented. A change in the threshold voltage of one or more transistors may in turn require a change in the supply voltage supplied to the IC. Generally speaking, an increase in the absolute value of a threshold voltage of one or more transistors in an IC may correspond to an increase in the required supply voltage for correct operation.
One common degradation mechanism that manifests itself during the aging of transistors in electronic circuits is negative bias temperature instability (NBTI), which may apply to PMOS (p-channel metal oxide semiconductor) transistors. The affects on a PMOS transistor of NBTI over a period of time may cause an increase in the absolute value of the threshold voltage, along with a decrease in drain current and transconductance. As the absolute value of the transistor's threshold voltage increase over time, a higher supply voltage value is required to ensure that the circuit operates properly. A similar phenomenon, positive bias temperature instability (PBTI) may affect NMOS (n-channel metal oxide semiconductor) transistors. Another potential degradation mechanism is hot carrier injection (HCI), wherein electrons or holes may gain sufficient kinetic energy to overcome potential barriers between different portions of the silicon (e.g., the potential barrier between the silicon substrate and the gate dielectric). Over time, HCI may degrade the gate dielectric of a transistor, increase its sub-threshold leakage current, and may also shift the threshold voltage.


The following is not an admission that anything discussed below is part of the prior art or part of the common general knowledge of a person skilled in the art.
Various types of surface cleaning apparatus are known. Surface cleaning apparatus include vacuum cleaners. Currently, a vacuum cleaner typically uses at least one cyclonic cleaning stage. More recently, cyclonic hand vacuum cleaners have been developed. See for example, U.S. Pat. No. 7,931,716 and US 2010/0229328. Each of these discloses a hand vacuum cleaner which includes a cyclonic cleaning stage. U.S. Pat. No. 7,931,716 discloses a cyclonic cleaning stage utilizing two cyclonic cleaning stages wherein both cyclonic stages have cyclone axis of rotation that extends vertically. US 2010/0229328 discloses a cyclonic hand vacuum cleaner wherein the cyclone axis of rotation extends horizontally and is co-axial with the suction motor. In addition, hand carriable cyclonic vacuum cleaners are also known (see U.S. Pat. No. 8,146,201 and U.S. Pat. No. 8,549,703).


1. Field of the Invention
The present invention relates to a face image obtaining apparatus for obtaining a face image to be attached to a personal paper or the like belonging to an individual, in particular, ID card, magnetic card, or the like. More specifically, the present invention relates to a face image obtaining apparatus having hand-related biological information obtaining function, as well as providing a face image of the user.
2. Description of the Related Art
Currently, unattended face image obtaining apparatuses for providing face images of the users are installed on the street. Such apparatuses provide recorded face images to the users by printing on plain papers or stickers.
In addition, a face image obtaining apparatus capable of obtaining biological information of the user such as fingerprint and the like, as well as face image, is proposed as described, for example, in International Patent Publication No. WO2005/050508. In the apparatus disclosed in the aforementioned patent publication, a face image of the user is recorded first, then the biological information. The apparatus records monitoring photographs, including a face image of the user, before and after obtaining biological information in order to provide a proof record when the user is switched for counterfeiting purpose. Such monitoring photographs may have a deterrent effect on the counterfeiting user switching. But, it is difficult to prevent such counterfeiting user switching at the site where the biological information and face image are obtained.
In order to prevent such counterfeiting user switching, a face image obtaining apparatus in which the face image and biological information are obtained at the same time has also been considered. If, for example, a fingerprint is obtained as the biological information, it is not an easy task for the user not accustomed to taking a fingerprint to obtain a face image and a proper fingerprint applicable to fingerprint authentication at the same time. When a user initially failed to obtain a fingerprint, if reacquisition of the fingerprint is authorized, the counterfeiting user switching may not be prevented.
In the mean time, another face image obtaining apparatus is also proposed as described, for example, in International Patent Publication No. WO2005/050508. In the apparatus, biological information is obtained before a face image, and when obtaining the face image, the biological information is obtained again to verify the identity of the user.
The face image obtaining means described in Japanese Unexamined Patent Publication No. 2005-141429 may prevent the counterfeiting user switching, but has a problem that the biological information needs to be reacquired when recording the face image, which increases the burden on the user.
The present invention has been developed in view of the problem described above, and it is an object of the present invention to provide a face image obtaining apparatus capable of reliably obtaining biological information applicable to authentication, and preventing counterfeiting user switching without increasing the burden on the user.


This invention relates to an automotive vehicle, especially a passenger car, having a bumper, at least two radiators, and an air duct for guiding the cooling air stream over the radiators. The air duct has an inlet port provided with air directing means.
German Unexamined Published Patent Application 2,306,317 shows an automotive vehicle which has two series-arranged radiators extending transversely to the driving direction. A common air duct is associated with the two radiators. The air duct includes two walls forming a tunnel and air directing means provided between the walls in the area of the cooling air inlet port. The air directing means is formed from a separately manufactured synthetic resin component.
A disadvantage of this arrangement is that the radiators, disposed in a common duct, are not exposed to an adequately defined throughflow of cooling air, as is required, for example, for a supercharger air cooler and an engine radiator.
Moreover, this air duct must be large in cross-sectional area to accomodate the necessary air flow for the radiators, since the cooling air inlet port is located in an area of relatively low dynamic pressure. Furthermore, design freedom in the front end space is impaired by the large-area structure of the air duct. Another drawback is that the air duct, which consists of several parts, is relatively expensive to manufacture and assemble.
It is an object of this invention to provide, for an automotive vehicle having at least two radiators, a cooling air guide system which is simple in construction, which functions satisfactorily, and which can be integrated into the vehicle with few problems.
These objects are attained in a cooling air guidance system which comprises a separate air duct for each radiator. Each air duct has an inlet port provided with means for directing the cooling air flow. The inlet ports and the air directing means are arranged in an elastic cover of the bumper. One of the air ducts extends, in part, through an opening in a rigid support member for the bumper. To increase cooling efficiency, at least one of the inlet ports is located in an area of maximum dynamic pressure, e.g., below a nose-shaped projection of the bumper cover.
The two radiators and their respective air ducts are preferably arranged in upper and lower vertical relation. Each air duct is formed by an air guide housing, detachably connected to the radiator and the inlet port. The housings are preferably made of a synthetic resin by a blow-molding technique.
The lower inlet port is formed by a plurality of vertically spaced slotted openings which extend transversely to the vehicle. Ribs in the bumper cover extend between the slotted openings and serve as means for directing the cooling air stream.
The bumper is supported by a rigid support member which is open, relative to the longitudinal axis of the vehicle, and which is situated directly behind the upper inlet port. The support member forms a portion of the upper air duct. The support is formed by two generally horizontal plate members, spaced vertically a distance from each other. The panels are held in position by locally arranged holders and spacer elements. The panels are fastened to the holders and spacers by fasteners, such as screws, rivets and the like.
The primary advantage attained by the invention is improved cooling as a result of providing each radiator with its own air duct. By locating the inlet ports in an area of maximum dynamic pressure, an increased air flow rate is attained with a smaller air duct cross section. This allows for reductions in the cross section of the air duct and the dimensions of the radiators. The inlet ports can also be made substantially smaller in size if they are located in an area of high, rather than low, dynamic pressure. Since the bumper (support and cover) is utilized for forming the cooling air guide system, the space available at that location is more effectively used.
By arranging the inlet ports and the air directing means in the elastic cover of the bumper and by manufacturing the air guide housings of a synthetic resin by a blow-molding method, a simple and economically producible cooling air guide system is created which can be mounted in a rapid and simple fashion. The bumper support, which consists of two panels with associated holder and spacer elements, is simple in construction and can be inexpensively manufactured.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.


From DE 102 60 000 B4 by the present applicant a wheel-force dynamometer for measuring tire forces is known, wherein a vehicle wheel is fixed onto a wheel axle which is mounted by roller bearings in a hollow shaft. The hollow shaft is mounted hydrostatically in a housing fixed to a frame and has a collar in which force sensors for the measurement of forces and torques are arranged. The forces acting on the wheel are thus transmitted, via the wheel axle, to the hollow shaft, which for its part “floats” in a frictionless manner by hydrostatic means in the housing. During the measurement of tire forces by a wheel-force dynamometer measurement errors can occur, which are determined by the design of the measuring device and its vibration behavior.


The invention relates to an inductive sensor head for detecting a ferrous, ferric and/or nonferrous electrically conducting objects buried in a surrounding medium.
Metal detectors for detecting ferrous or non-ferrous objects in media like walls of concrete, brick, plaster or the like or in the ground based upon the disturbance or modulation of the inductive coupling between two coils are known in the art. For example, U.S. Pat. No. 5,729,143 describes a microprocessor controlled metal detector which uses a transmitter coil providing a periodically varying magnetic field in combination with a receiver coil connected thereto in an inductive bridge. The detector comprises means for automatically balancing the two overlappingly arranged coils and electronically compensating any initial coil misalignments or unwanted signals, in particular, during an initial calibration step. In a known metal detector, one of the coils, the field coil, generates an alternating magnetic field while the other coil, the sense coil, measures changes caused by a ferrous or non-ferrous material coming into the magnetic flux field while moving the detector over the medium containing the hidden disturbing object.
A problem with the known metal detectors is, on the one hand, the relatively large size, which is unavoidable due to the side-by-side arrangement of the field coil and the sensor coil and, on the other hand, the fact that the detector must be swept over a certain search area in a kind of scanning process.
It is an object of the invention to provide an inductive sensor head which is small in size and may be used as a hand-held tool or may be integrated into an electric hand-held tool, preferably, a drill hammer.
It is a further object of the invention to provide an inductive sensor head which provides sufficient clear information about a hidden ferrous or non-ferrous electrically conducting object without the necessity of sweeping the sensor head over a certain working area of the medium in which said object may be buried.
The invention provides an inductive sensor head for detecting of ferrous or non-ferrous electrically conducting objects hidden. In particular, such a sensor head comprises at least one larger diameter field coil with a small axial length-to-diameter-ratio and at least one twin pair of co-axially arranged sense coils both having a small diameter compared to the diameter of the field coil. Preferably, the inductance of the sense coil is significantly higher than the inductance of the field coil. The higher the inductance the more sensitive the sense coil is to magnetic changes and the less gain is needed in the amplifiers that follow such elements. The common axis of the twin pair of sense coils extends perpendicular to the axis and in a diameter direction to the field coil, and the axis is positioned in a plane of the winding plane of the field coil or in a plane essentially parallel to the winding plane of that field coil. Further, the two sense coils are positioned in an equal distance from the center of the field coil such that they are penetrated by the same magnetic flux direction of the flux field emanating from the field coil when excitated by an electric current.
For achieving better positional information, in particular for resolving depth information in relation to a hidden object, e.g., a reenforcing bar (xe2x80x9crebarxe2x80x9d in the following) from a single position measurement cycle, a significant improvement of the invention is achieved if a twin pair of coaxially positioned field coils is provided. The mutual axial distance of the two field coils can be rather close and may preferably be less than their internal diameter. As a rule, the distance between the field coils is arranged such that the difference in magnetic field strength on a rebar is sufficiently large that it can be accurately measured. In addition, two twin pairs of sense coils with orthogonally arranged axes are positioned in a center plane parallel and approximately at a halfway distance between the winding planes of the two field coils.
As will be described in the following further details, the invention also provides an advantageous driving circuit for the combination of a twin pair of field coils and a double twin-set of sense coils, wherein additional correction coils are provided in series connection with each of the two field coils in order to minimize magnetic offsets due to the fact that the sense coils cannot be or are difficult to be exactly positioned in the magnetic null position of both field coils.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by it use, references should be had to the drawings and description matter in which there are illustrated and described preferred embodiments of the invention.


The present invention relates to a rotor for a rotary electric machine.
A structure of a conventional rotor core of a wound rotor having a rotor coil for a rotary electric machine is constructed by punching a silicon steel plate in a disc shape and laminating the disc-shaped plates.
However, since the punching die used to punch the steel plate is large in size in the case of a large-sized rotary electric machine, a rotor core is constructed, due to the above mentioned restriction in the manufacture of the rotor core, for example, as shown in FIG. 4, by punching a silicon steel plate in a sector shape, then arranging sector-shaped steel plates in a circle as shown in FIGS. 6(A) and 6(B), and laminating them.
In FIGS. 4, 5, 6(A) and 6(B), reference numeral 1 denotes a rotor core, symbol la denotes rotor core pieces made of a punched silicon steel plate, numeral 2 denotes slots to which a rotor coil is inserted, numeral 3 denotes a clamping bolt hole through which a clamping bolt is penetrated, numeral 4 denotes keyways for coupling the rotor core 1, for example, to a spider boss, numeral 5 denotes a ventilation duct for ventilating to cool the rotor, numeral 6 denotes a rotor coil, numeral 7 denotes a retainer for clamping the rotor core to integrate them by clamping the rotor core pieces la, numeral 8 denotes a ventilation fan for blowing cooling air to the stator, numeral 9 denotes a spider boss, and numeral 10 denotes a rotational shaft. The slots 2 are shown only in FIG. 4 for the simplification of the illustration.
Then, a method of manufacturing the conventional rotor will be described.
The rotor core 1 having a large diameter is generally formed by punching a thin silicon steel plate in a sector shape as shown in FIG. 4 to form rotor core pieces 1a. Then, the rotor core pieces 1a are stacked in a cylindrical shape while providing the ventilation duct 5 as shown in the sectional view of FIG. 5. In other words, a plurality of the rotor core pieces 1a are disposed horizontally to form one circular shape, and then the layers each formed of the one circular-shaped thin plates made of the rotor core pieces 1a are sequentially stacked upward similarly to the above. In the case of FIG. 4, 10 sheets of the core pieces 1a are disposed horizontally in one circular shape as one layer, and the layers thus formed are sequentially stacked upward. As described above, the rotor core pieces 1a thus stacked are clamped by penetrating the clamping bolts through the clamping bolt holes 3, and the rotor core 1 is constructed by providing the retainers 7 for clamping the rotor core at the upper and lower ends of the rotor core pieces 1a thus stacked, penetrating the clamping bolts therethrough, and clamping them with the clamping bolts in the axial direction.
The slots 2 for inserting the rotor coil 6 are formed at the outer periphery of the rotor core 1. After the rotor core 1 is constructed, the rotor coil 6 is inserted into the slots 2, and fixed in the slots 2 by inserting wedges to the outer peripheral ends of the slots 2.
A torque is transmitted between the spider boss 9 and the rotor core 1 through keys inserted into the keyways 4.
As described above, the rotor core pieces 1a are arranged horizontally in one circular shape, and the layers of the circular-shaped thin plates made of the rotor core pieces 1a are sequentially stacked. FIGS. 6(A) and 6(B) show the case where the rotor core pieces 1a are lap stacked at each 1/4 of one circle. More specifically, the rotor core pieces 1a shown in FIG. 4 are aligned in one circular shape on the outer periphery of the spider boss 9. In the case of the rotor core piece shown in FIG. 4, when ten sheets of the rotor core pieces 1a are aligned horizontally, they form one circular shape, and the split positions of the sectors are as designated by thick solid lines indicated by numeral 11 in FIG. 6(A).
When the second layer of the rotor core pieces 1a shown in FIG. 6(B) is so arranged in one circular shape that the split position is disposed at the position displaced by 1/4 of one sector from the split position 1 of the first layer of the rotor core pieces 1a, the split position of the second sector is disposed at the portion designated by a fine solid line indicated by numeral 12 in FIG. 6(A).
Similarly, when the third and fourth layers of the rotor core pieces 1a are stacked by displacing them by 1/4 of one sector from the split position, the split positions of the sectors are disposed at the positions designated by a broken line indicated by numeral 13 and a dotted broken line indicated by numeral 14, respectively.
The conventional rotor core 1 is constructed in the cylindrical structure by sequentially stacking the layers of the rotor core pieces 1a arranged horizontally in one circular shape as described above, providing the ventilation ducts 5 between several layers, and stacking the layers of the rotor core pieces 1a to a predetermined core length.
The rotor core 1 is constructed by stacking the layers of the rotor core pieces 1a, and then integrally clamping the stacked rotor core pieces through the retainers 7 disposed at the upper and lower ends thereof with the clamping bolts.
Since the conventional rotor core is constructed as described above, it is necessary to disassemble the rotor coil and to disassemble all the rotor core pieces after the rotor is assembled and tested for its factory test if the entire rotor cannot be transported as a unit due to limitations in transportation. Thus, it is also needed to reassemble the rotor coil and the rotor core pieces at a site after the disassembled rotor is transported to a place where the rotor is to be installed. Therefore, it takes a long time to disassemble the rotor in the factory, to transport the disassembled rotor and to reassemble the rotor, and there may be a problem in reliability of the performance of the reassembled rotor. It is an object of this invention to overcome this problem.


Retail, office and home environments frequently make use of shelving, and lighting to illuminate or even showcase items on a shelf. Movable shelves are often supported on shelf brackets, which attached to shelf support columns. Typically, each shelf support column attaches to a wall or other supporting member, and has a series of apertures to which the shelf brackets affix. A shelf or a series of shelves is generally supported by two shelf support columns, one at each end of the shelf, and optionally one or more additional shelf support columns in the middle. It would be advantageous to provide for lighting or other electrical needs at the shelves.
U.S. Pat. No. 5,695,261 describes a modular furniture system having vertical standards with internal conductors. The conductors are coupled to a source of low-voltage electrical power such that adjacent vertical standards are of differing electrical polarity. Brackets supporting the shelves of the modular furniture system make electrical contact with the internal conductors when a bracket is engaged in a vertical standard. A light fixture, coupled between a pair of brackets engaged with adjacent vertical standards, can be energized. Yet, there is a need in the art for improvements and alternatives to the above-described system.


The present invention relates to a composition comprising a polyarylene ether and a dispersible reactive solvent. Polyarylene ethers (PAEs) are a class of thermoplastic resins with excellent mechanical and electrical properties, heat resistance, flame retardancy, low moisture absorption, and dimensional stability. These resins are widely used in automobile interiors, particularly instrument panels, and electrical as well as electronic applications.
PAEs are very difficult to process (for example, by injection molding) as a result of their high melt viscosities and their high processing temperature relative to their oxidative degradation temperature. Consequently, PAEs are commonly blended with compatible polymers such as polystyrene (WO 97/21771 and U.S. Pat. No. 4,804,712); polyamides (U.S. Pat. No. 3,379,792); polyolefins (U.S. Pat. No. 3,351,851); rubber-modified styrene resins (U.S. Pat. Nos. 3,383,435 and 3,959,211, and Ger. Offen. No. 2,047,613); and mixtures of polystyrene and polycarbonate (U.S. Pat. Nos. 3,933,941 and 4,446,278). Unfortunately, improvements in processing have generally been obtained at the expense of flexural modulus, flexural strength, or heat distortion temperature.
Epoxy resins have also been investigated as a reactive solvent for the PAE. (See Venderbosch, R. W., "Processing of Intractable Polymers using Reactive Solvents," Ph.D. Thesis, Eindhoven (1995); Vanderbosch et al., Polymer, Vol. 35, p. 4349 (1994); Vanderbosch et al., Polymer, Vol. 36, p. 1167 (1995a); and Vanderbosch et al., Polymer, Vol. 36, p. 2903 (1995b)). In this instance, the PAE is first dissolved in an epoxy resin to form a solution that is preferably homogeneous. An article is then shaped from the solution, and the solution is cured at elevated temperatures, resulting in a phase separation that can give a continuous PAE phase with epoxy domains interspersed therein. The properties of the finished article are primarily determined by the PAE; however, the use of an epoxy resin as a reactive solvent for the PAE is not practical in a continuous melt process like injection molding because the epoxy resin needs a curing agent to set. The curing agent will, over time, accumulate in the injection molding barrel, thereby fouling the machine. Furthermore, the cure and subsequent phase separation has to take place at at least 150.degree. C., which is impractical in a molder environment.
In view of the deficiencies in the art, it would be desirable to find a reactive solvent that would solve the processing problems inherent in some reactive solvents for PAE, without deleteriously affecting the physical properties of the PAE.


Mobile or wireless communications networks are capable of carrying traffic (e.g., voice traffic, data traffic, etc.) between mobile stations and other endpoints, which can be another mobile station or an endpoint connected to a network such as a public-switched telephone network (PSTN) or a packet data network (e.g., local area networks, the Internet, and so forth). Examples of wireless communications networks include those that operate according to the GSM (Global System for Mobile) or UMTS (Universal Mobile Telecommunications System) standards, as defined by the Third Generation Partnership Project (3GPP). Another type of wireless communications network is according to the Code Division Multiple Access (CDMA) 2000 standards, as defined by 3GPP2.
A media gateway is often provided between a radio access network (which is part of the core network of the wireless communications network) and a fixed network such as a PSTN, an Internet Protocol network, or other network. The media gateway performs various signal processing tasks with respect to bearer traffic (e.g., voice traffic) communicated between the radio access network and the fixed network. The signal processing includes encoding and decoding of the bearer traffic, with the encoding and decoding typically performed by a digital signal processor (DSP). The DSP is a shared resource that can be shared by multiple call sessions (or call contexts). Multiple events (e.g., encoding or decoding events) associated with the call contexts are scheduled so that the DSP processes the events one at a time according to the schedule. Conventional scheduling techniques do not allow for efficient handling of dynamically changing numbers of events that are to be processed by the DSP.


With portable electric tools there is a need to simplify assembly to both reduce production costs and to reduce the risk of assembly errors. This has become more important as such tools have become more sophisticated in their functioning.
In the manufacture of electric motors for such tools, it is becoming increasingly common practice to wind the field coils mechanically on to the stator and to provide terminations on the latter for receiving the ends of the field coil windings and which facilitate electrical connection of the windings to the commutator brushes. The stator assembly can be formed by a stack of field laminations and a plurality of coils, and be adapted for automatic connection of the coils to terminal means mounted on the stack wherein the terminal means and mounting means lie entirely within an area defined by the outline of the field laminations. Such an arrangement is disclosed in U.S. Pat. No. 4,071,793 which is hereby incorporated by reference.
Improvements have been made in the manner of connecting the electric leads to the stator assembly. In one such arrangement a pair of blocks made from suitable insulating material such as a polysulphone are located in slots in the stator laminated stack, these blocks being provided with a pair of apertures for receiving a conductive terminal. Each terminal comprises a sleeve portion for engaging in the aperture and a channel portion connected to the sleeve portion by a short connecting neck. A wire to be attached is crimped in the channel portion. Such an arrangement is disclosed in British Pat. No. 1,402,591 which is hereby incorporated by reference. When this method of connecting electrical leads is used with the stator assembly referred to above, the stator assembly can be readily manufactured as a separate unit which is then easily insertable into the housing of the portable electric tool and then the electrical connections to be made to it can be made simply and effectively.
It has been proposed to mount a printed circuit board on a plate having attached thereto carbon brush assemblies, with the plate being attached to the housing of the tool. The armature of the electric motor passes through central openings in both the plate and the printed circuit board.
In order to reverse the rotational direction of drive of an electric tool, a separate reversing switch can be incorporated. However, with many forms of motors, for example, universal motors, damage can occur if the reversing switch is operated to reverse the direction of electrical supply to the motor whilst it is still rotating. To eliminate this danger of damage occurring to the electrical motor, it has been proposed to incorporate the reversing switch in a trigger switch for energizing the tool. The trigger switch is mounted, as well known, in the handle of the tool, and the actuating member of the reversing switch is disposed immediately above the trigger of the trigger switch and just below the motor compartment of the tool. The actuating member of the reversing switch and the trigger are mechanically related so that the trigger remains inoperative, i.e. it cannot be moved, until the actuating member of the reversing switch is positioned to one side of the trigger to allow the motor to be energized to rotate in one direction, or until the actuating member is positioned to the other side of the trigger to reverse the direction of rotation of the motor.
A disadvantage of this reversing switch and trigger switch combination is that it complicates the number of electrical wires that have to feed from the handle of the tool through to the motor compartment and also the number of electrical connections that have to be made to the combined switches in the handle.
The present invention is concerned with further simplifying the assembly of portable electric tools.
It is an object of this invention to provide a portable electric tool having a reversing switch interrelated with a main energizing switch and being arranged so that the number of electrical wires feeding from the handle to the motor compartment can be reduced by at least two.
It is another object of this invention to provide a portable electric tool having a printed circuit board assembly in the motor compartment with the reversing switch being part of that assembly.
It is yet a further object of this invention to provide a portable electric tool having a comprehensive printed circuit board assembly in the motor compartment and being readily mounted on a stator lamination stack of the electric motor.


This section provides background information related to the present disclosure which is not necessarily prior art.
FIG. 1 is a view illustrating an example of the semiconductor light emitting device proposed in U.S. Pat. No. 7,262,436. The semiconductor light emitting device includes a substrate 100, an n-type semiconductor layer 300 grown on the substrate 100, an active layer 400 grown on the n-type semiconductor layer 300, a p-type semiconductor layer 500 grown on the active layer 400, electrodes 901, 902 and 903 formed on the p-type semiconductor layer 500, while serving as reflective films, and an n-side bonding pad 800 formed on the n-type semiconductor layer 300 which has been etched and exposed. The n-type semiconductor layer 300 and the p-type semiconductor layer 500 can be of opposite conductive types. Preferably, a buffer layer (not shown) is provided between the substrate 100 and the n-type semiconductor layer 300. A chip having this structure, i.e. where all the electrodes 901, 902 and 903 and the n-side bonding pad 800 are formed on the opposite side of the substrate 100, with the electrodes 901, 902 and 903 serving as reflective films, is called a flip-chip. The electrodes 901, 902 and 903 are made up of an electrode 901 (e.g., Ag) with a high reflectance, an electrode 903 (e.g., Au) for bonding, and an electrode 902 (e.g., Ni) for preventing diffusion between materials of the electrode 901 and materials of the electrode 903. While this metal reflective film structure has a high reflectance and is advantageous for current spreading, it has a drawback that the metal absorbs light.
FIG. 2 is a view illustrating an example of the semiconductor light emitting device proposed in JP Pub. No. 2006-120913. The semiconductor light emitting device includes a substrate 100, a buffer layer grown on the substrate 100, an n-type semiconductor layer 300 grown on the buffer layer 200, an active layer 400 grown on the n-type semiconductor layer 300, a p-type semiconductor layer 500 grown on the active layer 400, a light-transmitting conductive film 600 with a current spreading function formed on the p-type semiconductor layer 500, a p-side bonding pad 700 formed on the light-transmitting conductive film 600, and an n-side bonding pad 800 formed on the n-type semiconductor layer 300 which has been etched and exposed. Further, a DBR (Distributed Bragg Reflector) 900 and a metal reflective film 904 are provided on the light-transmitting conductive film 600. While this structure reduces light absorption by the metal reflective film 904, it has a drawback that current spreading is relatively poor, compared with the use of the electrodes 901, 902 and 903.
FIG. 12 is a view illustrating an example of the semiconductor light emitting device proposed in JP Pub. No. 2009-164423. In the semiconductor light emitting device, a DBR 900 and a metal reflective film 904 are provided on a plurality of semiconductor layers 300, 400 and 500, a phosphor 1000 is provided on opposite side thereof. The metal reflective film 904 and an n-side bonding pad 800 are electrically connected with external electrodes 1100 and 1200. The external electrodes 1100 and 1200 can be lead frames for a package, or electrical patterns provided on the COB (Chip on Board) or PCB (Printed Circuit Board). The phosphor 1000 can be coated conformally, or can be mixed with an epoxy resin and then used to cover the external electrodes 1100 and 1200. The phosphor 1000 absorbs light that is generated in the active layer, and converts this light to a light of longer or shorter wavelength.


1. Field of the Invention
The present invention relates generally to voltage regulators, and more particularly to a frequency sensing voltage regulator that uses the system operating frequency to limit the amount of current delivered to a load, thereby regulating the variance of the supply voltage to the load.
2. Description of the Related Art
Voltage regulator circuits are known in which a voltage supply to a load is regulated by controlling the current supplied to the load. Typical of such prior art structures is the use of a negative feedback circuit for sensing the output voltage and/or output current which is used for comparison with a reference voltage/reference current. The difference between the output and the reference signal is used to adjust the current supplied to a load.
There are problems, however, with such voltage regulators. A considerable amount of power is drawn, and thus heat dissipated, because of the use of the negative feedback circuit. In addition, the negative feedback circuit decreases the response time to sharp current fluctuations. Furthermore, the comparator circuits and reference level generating circuits take up considerable layout area when the voltage regulator is incorporated in an integrated circuit (IC) structure.
Additional problems also occur when a voltage regulator is used to regulate the supply voltage to a synchronous device, such as a synchronous memory device, for example an SRAM. In an SRAM, an external supply voltage, Vcc, must be maintained within a predetermined level. The external supply voltage Vcc must be regulated to produce a regulated Vcc value during periods of considerable current fluctuation. For example, an SRAM load current may quickly fluctuate between microamps and milliamps during use. Such changes in the load current can cause significant variation on the regulated Vcc value, which can result in improper operation of the SRAM or possibly even damage to the SRAM.
Thus, there exists a need for a voltage regulator that is easy to implement, does not occupy significant layout area when the voltage regulator is incorporated in an integrated circuit (IC), and provides a minimal variance of the supply voltage Vcc over a wide current range.


In recent years, a motor wherein current paths are electronically altered by plural transistors has been widely used as a drive motor in office automation equipment and audio-visual equipment. A disk drive apparatus, such as an optical disc drive apparatus (DVD, CD, and the like) and a magnetic disk drive apparatus (HDD, FDD, and the like), includes such a motor. As an example of such a conventional motor, a motor wherein current paths are altered by PNP-type and NPN-type bipolar power transistors is disclosed on lines 16 to 31 in the first column and FIG. 34 in the specification of the U.S. Pat. No. 5,982,118.
FIG. 35 shows a prior art motor, and the operation of the prior art motor is described below. A rotor 2011 has a field part formed by a permanent magnet. In a position detector 2041, three position sensors detect the magnetic field of the field part of the rotor 2011. In other words, the position detector 2041 produces two sets of three-phase voltage signals, that is, Kp1, Kp2 and Kp3, and Kp4, Kp5 and Kp6, in response to the three-phase output signals of the three position sensors in response to the rotation of the rotor 2011. A first distributor 2042 produces three-phase lower-side signals Mp1 Mp2 and Mp3 in response to the voltage signals Kp1, Kp2 and Kp3, thereby controlling the activation of lower-side NPN-type bipolar power transistors 2021, 2022 and 2023. A second distributor 2043 produces three-phase higher-side signals Mp4, Mp5 and Mp6 in response to the voltage signals Kp4, Kp5 and Kp6, thereby controlling the activation of the upper-side PNP-type bipolar power transistors 2025, 2026 and 2027. Accordingly, three-phase drive voltages are supplied to windings 2012, 2013 and 2014.
In the prior art configuration shown in FIG. 35, the position detector 2041 comprises three position sensors for detecting the rotational position of the rotor 2011. This has caused the necessity of a substantial space for installing these position sensors and the complexity of the wiring, resulting in an increase in cost. On the other hand, a motor with no position sensor is disclosed on line 54 of the second column to line 45 of the third column and FIG. 1 in the specification of the U.S. Pat. No. 5,473,232. In the motor, the back-electromotive forces of the windings are detected so as to obtain the rotational position of the rotor. In the motor with no position sensor, however, the rotational position cannot be detected correctly at a low rotational speed of the motor, since the magnitudes of the back-electromotive forces become too small to detect at a low rotational speed of the motor. So, it is difficult to drive and control the motor at a low speed. In particular, in the case when the rotational speed is controlled by using a pulse signal which responds with the detected back-electromotive forces, a large fluctuation occurs in the rotational speed of the motor at a low speed because of the inaccurate detection of the pulse signal.
A motor with a single position sensor is disclosed on line 30 of the fifth column to line 41 of the 12th column and FIG. 1 in the specification of the U.S. Pat. No. 5,729,102. In the motor, the rotational electrical angle is estimated from the output of the single position sensor, and sinusoidal currents are supplied to the windings in response to the estimated rotational electrical angle. However, in the case of the motor with the single position sensor, positional information in the stop state of the rotor is insufficient, thereby starting and acceleration of the motor with the single position sensor becomes unstable. Accordingly, the starting and acceleration of the rotor are not carried out smoothly, resulting in a starting failure. Furthermore, in the configuration of the motor according to the specification of the U.S. Pat. No. 5,729,102, it is difficult to estimate the rotational electrical angle with a fine step resolution. In particular, the error in the estimated electrical angle becomes larger at a higher rotational speed. Accordingly, precise rotation control of the motor has been difficult.
In an optical disc drive apparatus for reproducing signals from DVD-ROM, CD-ROM, and CD disks, stable operation is required over a wide range of rotational speed from 10,000 rpm for high-speed reproduction to 200 rpm for CD reproduction. In a rewritable disk drive apparatus for recording information on a high-density disk and/or reproducing information from a high-density disk such as DVD-RAM/RW and CD-R/RW, the disk is required to be rotated precisely. In these disc drive apparatuses, it is necessary to smoothly start and accelerate the disk and to carry out information reproduction in a short time. In addition to the optical disc drive apparatuses, magnetic disc drive apparatuses such as HDD and FDD are also required to be low cost and to carry out stable rotation of the disk during the whole operation which includes the operation of the starting and acceleration thereof.


Pectin polymers are important constituents of plant cell walls. Pectin is a hetero-polysaccharide with a backbone composed of alternating homogalacturonan (smooth regions) and rhamnogalacturonan (hairy regions). The smooth regions are linear polymers of 1,4-linked alpha-D-galacturonic acid. The galacturonic acid residues can be methyl-esterified on the carboxyl group to a varying degree, usually in a non-random fashion with blocks of polygalacturonic acid being completely methyl-esterified.
Pectinases can be classified according to their preferential substrate, highly methyl-esterified pectin or low methyl-esterified pectin and polygalacturonic acid (pectate), and their reaction mechanism, beta-elimination or hydrolysis. Pectinases can be mainly endo-acting, cutting the polymer at random sites within the chain to give a mixture of oligomers, or they may be exo-acting, attacking from one end of the polymer and producing monomers or dimers. Several pectinase activities acting on the smooth regions of pectin are included in the classification of enzymes provided by the Enzyme Nomenclature (1992) such as pectate lyase (EC 4.2.2.2), pectin lyase (EC 4.2.2.10), polygalacturonase (EC 3.2.1.15), exo-polygalacturonase (EC 3.2.1.67), exo-polygalacturonate lyase (EC 4.2.2.9) and exo-poly-alpha-galacturonosidase (EC 3.2.1.82).
Pectate lyases have been cloned from different bacterial genera such as Erwinia, Pseudomonas, Klebsiella and Xanthomonas. Also from Bacillus subtilis (Nasser et al. (1993) FEBS 335:319-326) and Bacillus sp. YA-14 (Kim et al. (1994) Biosci. Biotech. Biochem. 58:947-949) cloning of a pectate lyase has been described. Purification of pectate lyases with maximum activity in the pH range of 8-10 produced by Bacillus pumilus (Dave and Vaughn (1971) J. Bacteriol. 108:166-174), B. polymyxa (Nagel and Vaughn (1961) Arch. Biochem. Biophys. 93:344-352), B. stearothermophilus (Karbassi and Vaughn (1980) Can. J. Microbiol. 26:377-384), Bacillus sp. (Hasegawa and Nagel (1966) J. Food Sci. 31:838-845) and Bacillus sp. RK9 (Kelly and Fogarty (1978) Can. J. Microbiol. 24:1164-1172) has been reported, however, no publication was found on cloning of pectate lyase encoding genes from these organisms. All the pectate lyases described require divalent cations for maximum activity, calcium ions being the most stimulatory.
Generally, pectinase producing microorganisms exhibit a broad range of pectin degrading or modifying enzymes. Often the microorganisms also produce cellulases and/or hemicellulases and complex multi-component enzyme preparations from such microorganisms may be difficult to optimise for various applications, they even may contain enzymes with detrimental effect. Thus, it is an object of the present invention to provide a pectin degrading enzyme exhibiting only the desired effects e.g. in detergents or different industrial processes.


The present invention relates generally to fluid power systems, and more particularly to a fluid power system which includes two fluid power circuits and a means for controlling the pressure in one of the circuits in response to the pressure in the other circuit. Still more particularly, the invention relates to such a fluid power system for use in a dewatering filter press.
Dewatering filter presses are used to remove excess water from a slurry. In such filter presses, water pressure acts against a diaphragm to squeeze the water from the slurry while hydraulic pressure acts against a piston to provide a clamping force holding the press closed. In this type of press, the magnitude of the clamping force, and hence the magnitude of the hydraulic pressure in the clamping piston, must be proportional to the water pressure acting against the diaphragm. In the prior art, this is accomplished by using several pressure activated switches that are responsive to the water pressure acting against the diaphragm. This arrangement produces a clamping pressure that is not a linear function of the water pressure but instead is a stair step function of the water pressure.


1. Field of the Invention
The present invention relates to a photography device.
2. Description of the Related Art
Among photography devices in which a lens for photography is protruded through a protrusion aperture of a casing body, there are photography devices which are structured such that the protrusion aperture is covered by a lens barrier when the lens for photography is retracted into the casing body (stored).
For example, Japanese Patent No. 2,712,160 discloses a camera which is equipped with an urging mechanism and an operation mechanism. The urging mechanism urges the lens barrier in a closing direction. The operation mechanism moves the lens barrier to an open position, against urging force from the urging mechanism, and retains the lens barrier. Accordingly, operations to open and close the lens barrier are implemented simply and safely.
However, in an operation to close the lens barrier, the lens barrier temporarily abuts against a peripheral surface of a lens barrel and movement toward the closed position is obstructed. Thereafter, when the barrel has moved to a camera body side end of the movement thereof, the lens barrier is closed by the urging force from the urging mechanism. In this operation, because the lens barrier abuts against the lens barrel, there is a risk that damage or breakage may occur.
Similarly, in a retraction-type camera disclosed in Japanese Patent No. 3,078,408, when a barrier is being moved from a completely open position to a completely closed position, a trigger switch operates and a lens barrel starts to retract. When the barrier is moved further in the closing direction, clicking means operates, prompting a user to wait until the lens barrel has completely retracted. Then, when the retraction has completely finished and it is possible for the barrier to completely close, the barrier is moved so as to pass over the clicking means, and is completely closed.
In this structure, although impacts between the barrier and the lens barrel can be avoided at least, movement of the barrier is temporarily stopped at an intermediate position during complete closing of the barrier. Thus, there is a problem in that operability is poor.
Japanese Patent Application Laid-Open (JP-A) No. 7-49515 discloses a camera (lens device) which is equipped with a motor for implementing protrusion and withdrawal of a moveable barrel, and which is structured so as to rotate a lens barrier for closing while the moveable barrel is being withdrawn.
With this structure, a mechanism for transmitting driving force of the motor to the lens barrier is necessary, and there is a disadvantage in that the structure is complicated.


The present invention relates to a flexible polyurethane foam, its production method and a material system for its production.
In recent years, along with progress in an automobile industry, not only improvement in performance of an automobile but also a high degree of vehicle interior and improvement in interior comfort have been desired, and development of a flexible polyurethane foam for seat (hereinafter referred to as a flexible foam) having more excellent cushioning properties has been strongly desired in view of improvement in comfort to sit on and comfort to ride in.
Heretofore, as a seat cushion, a combination of metal springs and a pad material comprising a flexible foam has been used widely. However, in recent years, a seat for an automobile so-called full-foam type, wherein a flexible foam itself is made to have spring properties so that metal springs are not used, tends to be employed, with a demand for cost saving, weight saving, etc. The full-foam type seat tends to be thick since no metal spring is used together, and properties of the flexible foam are factors which greatly contribute to comfort to sit on and comfort to ride in of the seat. Namely, importance has been given to static characteristics and dynamic characteristics as indices of comfort to sit on and comfort to ride in, in development of a flexible foam. Particularly among the static characteristics, control of the feeling of support at the initial stage of sitting and the feeling of bottom out at the terminal stage of sitting are important.
When a person actually sits on a seat equipped with a pad material made of a flexible foam, the flexible foam is compressed and indented, and the position of e.g. the bottom falls to a certain height. As a method of measuring the static characteristics (static seat feeling), a load test in accordance with a performance test method of a pad material for a seat for an automobile in JASO (Japanese Automobile Standards Organization) B408-89, wherein a deflection is measured to obtain a load-deflection loop, is used. In FIG. 2 is shown a load-deflection loop of a conventional flexible foam. In the load-deflection loop, the value of the tangent of the tangent line at the pressing side (upper side in FIG. 2) at each load is the static spring constant. Namely, when the static spring constant is high, the curve has a steep slope and when the static spring constant is low, the curve has a gentle slope.
The load-deflection loop of a flexible foam usually rises quickly at the initial stage of application of the load, then gently increases at the inflection point 1 and with further application of the load, it rapidly increases at the inflection point 2. A flexible foam excellent in the feeling of support is considered to be such a flexible foam that the curve steeply rises at the initial stage of application of the load, and the static spring constant is high from the starting point to the vicinity of the inflection point 1. Further, a flexible foam which provides no feeling of bottom out and provides favorable comfort to sit on, is considered to be such a flexible foam that the static spring constant is low even in the high load region after the inflection point 2. Adjustment of hardness of the flexible foam has conventionally been carried out to obtain the feeling of support, however, in such a case, the static spring constant in the high load region tends to be high, and the feeling of bottom out can not be overcome.
Generally, a full-foam type flexible foam for seat provides a small deflection in the high load region as the static characteristics, it provides the feeling of bottom out, and the comfort to sit on tends to deteriorate, as compared with the foam for seat in combination with metal springs. In order to overcome such problems, a method has been known to make the foam thick or to increase the density to make the deflection large, however, problems of increase in cost and increase in the seat weight can not be overcome.
JP-A-11-322875 proposes a method of adding a specific fluorine type surfactant to a material for production of a polyurethane foam composed mainly of a polyol and an isocyanate component so as to increase the deflection. However, there are such problems that the feeling of support is insufficient, the fluorine type surfactant itself is expensive, thus increasing the cost, and the surface tension of the surfactant is low, whereby the inside of a mold at the time of foam production may be polluted.
Further, JP-A-5-320304 proposes a method for producing a polyurethane foam, which comprises reacting a polyol component comprising a polyol, a catalyst, a blowing agent and other additives, with a polyisocyanate component, wherein a specific bifunctional secondary amine is added, to produce a foam which provides a small slope of the pressing side curve at 75% deflection as a characteristic to evaluate the feeling of bottom out, which provides no feeling of bottom out, and which has a well balance among softness, degree of falling and vibrating property. However, the feeling of support is insufficient, and durability particularly heat and humid permanent compression set is insufficient.
Namely, such a flexible foam is not present that the static spring constant is high in the low load region, the feeling of support and rigidity are satisfied, and further, the static spring constant is low in the high load region, the deflection is large and the feeling of bottom out is overcome.
Under these circumstances, it is an object of the present invention to provide a flexible foam for an automobile seat, with which the feeling of bottom out is overcome, the feeling of support is favorable, and the comfort to sit on is significantly improved, and which has favorable vibrating property and durability, and a method for producing said foam and a material system for production of said foam.
The present inventors have conducted extensive studies to overcome the above problems and as a result, they have found a foam which exhibits a load-deflection loop which satisfies characteristic conditions in a load test of the flexible foam or in a load test of its core portion, and found that a foam having such a characteristic load-deflection loop significantly improves the comfort to sit on as the static seat feeling, when an automobile seat is molded (see FIG. 1). A foam which satisfies such conditions has such characteristics that the deflection is small at the initial stage of application of the load, the feeling of support is sufficient, and after that region, the rate of change of the static spring constant is small, and the curve gently increases. Namely, it is estimated that at the initial stage of sitting, the feeling of support is sufficient, whereby the foam is excellent in body weight support, and after a person sits on the foam, it is well bent, whereby the body weight is softly supported, and accordingly the feeling of bottom out is overcome, and the comfort to sit on becomes favorable.
Namely, the present invention provides a flexible polyurethane foam, wherein in a load (N)-deflection (mm) loop obtained by a load test of the flexible polyurethane foam, the X value as calculated from the formula (1) is at most 4.2:
X=(static spring constant at a load of 883N)/(static spring constant at a load of 98N)xe2x80x83xe2x80x83(1)
The present invention further provides a flexible polyurethane foam, wherein in a load (N)-deflection (mm) loop obtained by a load test of a core portion of the flexible polyurethane foam, the Y value as calculated from the formula (2) is at most 1.8:
Y=(static spring constant at a load of 127.4N)/(static spring constant at a load of 19.6Nxe2x80x83xe2x80x83(2)
The present invention further provides a method for producing the above flexible polyurethane foam, which comprises reacting a polyol having from 5 to 85 mass % of an oxyethylene/oxypropylene random chain, the oxyethylene group content in the random chain being from 3 to 40 mass % and the content of the terminal oxyethylene block chain being from 3 to 40 mass %, and having a hydroxyl value of from 10 to 56 mgKOH/g and a degree of unsaturation of at most 0.04 meq/g, with a polyisocyanate in the presence of a blowing agent and a catalyst.
Still further, the present invention provides a material system for production of the above flexible polyurethane foam, which comprises a polyol system liquid containing a polyol having from 5 to 85 mass % of an oxyethylene/oxypropylene random chain, the oxyethylene group content in the random chain being from 3 to 40 mass % and the content of the terminal oxyethylene block chain being from 3 to 40 mass %, and having a hydroxyl value of from 10 to 56 mgKOH/g and a degree of unsaturation of at most 0.04 meq/g, and a polyisocyanate.


This invention relates to controlling the operation of refrigeration systems which contain multiple compressors. More particularly, the present invention is concerned with refrigeration systems of the type having multiple compressors fed from a common suction manifold and which deliver refrigerant gas under pressure to a common head pressure manifold.
It is known from U.S. Pat. No. 3,599,006 to John L. Harris granted Aug. 10, 1971 and entitled "Condition Control Device and System" to provide multiple compressors in a refrigeration system. The system is arranged so that the compressors are started in sequence, allowing each compressor to come up to speed before the next compressor is started. The system also interposes a delay between the stopping and restarting of the respective compressors so that a compressor is not started under heavy load. The system is essentially an electromechanical system responsive to analog signals and completely analog in nature.
It is known from U.S. Pat. No. 4,128,854 to Robert T. Ruminsky issued Dec. 5, 1978 and entitled "Compressor Minimum Off-time System" to place a current transformer in a circuit which controls the switching of a compressor. The current transformer, in turn, provides a control signal to a minimum off-time circuit. The purpose of the delay effected by the off-time circuit is to prevent start-up under heavy load. Like the system disclosed in Harris, supra, the system is analog in nature and is responsive to analog signals.
It is known from U.S. Pat. No. 3,636,369 to Donald G. Harter, granted on Jan. 18, 1972 and entitled "Refrigerant Compressor Control-relay to Control Two Time Delays" to provide a refrigerant compressor with a relay arrangement which controls two time delays. One time delay keeps the compressor deenergized at least for a predetermined period after each stop action. The other time delay keeps the compressor energized for at least a predetermined period after each start action.
It is known from U.S. Pat. No. 4,033,738 to Carl R. Metrola et al., granted on July 5, 1977 and entitled "Heat Pump System with Multi-stage Centrifugal Compressors" to arrange multistage compressors in series. The start of the second compressor is delayed for a sufficiently long period to enable the first compressor to reach its design speed.
The use of a microprocessor and timed solid state logic circuitry to control automatically sequencing of compressors in a refrigeration system is disclosed in U.S. Pat. No. 4,152,902 granted May 8, 1979 to Lawrence E. Lush and entitled "Control for Refrigerator Compressors".


This invention relates to electronic music systems, and more particularly relates to a method permitting interactive performance of music generated by an electronic music device. This invention is more specifically directed to synthesizer or computer-generated music, especially automatic or semiautomatic digital generation of music by algorithm (i.e., by computer program).
In the recent past, there have been proposed music generating systems, to be comprised of a digital computer and a music synthesizer coupled thereto. In performing typical such systems, the generated music is determined entirely by the user of the system, playing the role of performer or composer. The user first determines the nature of the sounds of the system produces by manipulating a plurality of controls, each associated with one or more parameters of the sound. Once the sounds are determined, the user performs music with the system in the manner of a traditional musical instrument, usually by using a piano-type keyboard.
A major problem with the traditional approach to music as applied in the above-mentioned systems, is that it requires a considerable technical knowledge of sounds that are produced and varied electronically. Another problem is that such systems produce each sound only in response to external stimuli (i.e., acts performed by the user of the system), thereby limiting the complexity of the system's output to what the user is capable of performing. Still another problem is that the relationship between the system and user is limited to the type of functioning typical of a traditional musical instrument, so that the user can relate to the system only as a performer relates to his or her instrument. A further problem is that the peformance device employed by the user is normally a fixed part of the system, and is not interchangeable with other peformance devices.
Previous systems have not automatically generated sounds, music, or performance information, while allowing a performer to interact with and influence the course of the music. No previous system designed for performance could be used effectively by a performer or user not having previously learned skills, such as those required to play a keyboard instrument.