An improved electric motor has a stator, and a hysteresis cylindrical ring formed of magnetic metallic material disposed within the stator cylindrical core with an annular air space between the hysteresis cylindrical ring and the stator core, and a rotor cylindrical sleeve formed of non-magnetic material relatively rotatably mounted within the hysteresis cylindrical ring on a suitable shaft. The improvement includes several interrelated elements. Firstly, the hysteresis cylindrical ring has four longitudinal, generally-rectangular slots spaced 90.degree. apart, and extending from an inner surface of the hysteresis cylindrical ring. Secondly, a permanent magnet is provided only in each of the slots. Thirdly, the rotor cylindrical sleeve has 4 longitudinally-extending, non-magnetically-retentive projections thereon, the projections being spaced 90.degree. apart. The rotor cylindrical sleeve thereby provides longitudinally-extending, annular air duct in each of the 4 sections. This provides an improved 4-pole combination hysteresis-reluctance-permanent-magnet electric motor.

(i) Field of the Invention
This invention relates to a permanent magnet hysteresis motor.
(ii) Description of the Prior Art
Electric motors containing magnets are well-known in the art.
Attempts have been made to employ permanent magnets instead of wire-wound direct current source for the excitation of synchronous machines. Previous efforts were somewhat unsuccessful for two major reasons. One reason was the unavailability of high coercive-force permanent magnets, while another reason was relatively higher per unit cost. The former is perhaps no longer applicable now because of the availability of high energy modern permanent magnets, e.g., ferrites, manganese-aluminum-carbon, samarium-cobalt, neodymium-boron-iron, etc.
The permanent magnet synchronous motor when connected to a balanced a.c. supply, will run up to synchronous speed, using its rotor cage windings for the starting torque purpose. During run-up period, the time-average motor torque has two components, namely the induction cage-torque and the permanent magnet brake-torque, which are mutually opposing in nature. When the motor attains synchronous speed the cage-torque reduces to zero, while the magnet-torque reverses its role and become the principal motor torque.
The stator of a permanent magnet synchronous motor is structurally similar to that of any conventional synchronous machine. The rotor has permanent magnets instead of wire-wound fields and its associated slip-ring and brush gears. Usually the rotor has squirrel-cage winding which provides the starting torque. The squirrel-cage-winding also acts as a preventive shield against the demagnetization of the permanent magnet due to armature reaction during run-up period. It also does provide the usual damping function against hunting. The power factor efficiency product of squirrel-cage permanent magnet synchronous motors is about 30-40 percent higher than that of induction motors for rating up to about 10 hp.
There are some merits offered by permanent magnet synchronous motors. However, the permanent magnet synchronous motor, when operated at line frequency, has a major drawback during the starting period as the magnets generate a braking torque which decreases the ability of the rotor to synchronize a load. This can be overcome by designing a cage winding having a high resistance to provide sufficient accelerating torque. The motor runs up from rest to near synchronous speed with the help of cage torque, and is then followed by a sudden acceleration into synchronization with the help of both the rotor saliency and magnets. When the motor has reached synchronous speed, the cage torque and its currents are reduced to zero, whereas the magnet torque becomes the sole source of motor torque. However, the rotor cage still provides the function of a damper winding during transient torque disturbances. During run-up, the instantaneous torque produced by such motors has two components, namely, the synchronous average torque and the pulsating torque. The average torque component is comprised of both the cage torque and magnet torque while the pulsating torque is comprised of pulsating cage torque and pulsating magnet torque components.
With recent advancements in magnet materials and solid state devices, there is now scope for large scale application of permanent magnet synchronous motors in variable speed drives. It has, however, been found that the permanent magnet motor becomes unstable when operated at low frequencies or is subjected to sudden changes in operating conditions. The instability is exhibited in the form of rotor oscillation around the mean synchronous speed. Such unstable operation is undesirable since permanent magnet motors are aimed at synchronous operation at all times. Therefore, stability problems emerge in the permanent magnet motor when it is subjected to small disturbances during steady state operation. Forced oscillation may also occur when there is an externally applied torque, voltage or change in one of the machine parameters.
Recent advances in the development of hard magnetic materials have spurred the provision of small and medium-sized brushless synchronous motors. This is, in part, due to changing markets for synchronous a.c. drives and power electronics for applications in computer, textile and glass industries, requiring precisely constant speed combined with smooth starting and braking capability, steady torque, brushless and relatively low noise operation. AC permanent magnet synchronous motors meet these drive constraints. Unlike induction motors, the speed of permanent magnet synchronous motor is uniquely determined by the inverter supply frequency irrespective of voltage, load, temperature and manufacturing variations. These motors are inherently high efficiency types, resulting in greater energy savings. There is no I.sup.2 R loss due to slip, as in induction motors. It has also no field losses like those in wire-wound conventional synchronous motors.
Both the permanent magnet synchronous motor and the conventional reluctance type synchronous motor are normally used in multimotor systems requiring synchronized operation from common inverter supply source. However, permanent magnet synchronous motors have several distinct advantages, namely, efficiency, high power factor, and relatively higher stability over the reluctance versions. Smooth brushless operation and simple rotor construction of permanent magnet synchronous motors offer additional advantages particularly for high speed applications.
The higher per unit cost still remains an obstacle for large scale industrial use of synchronous motors. However, the present concern of energy savings overrides the initial per unit higher costs of a synchronous motor. An efficient synchronous motor is cheaper to run over the life of a motor. High efficiency permanent magnet motors with improved power factors are fast catching up in the overall energy savings market. Savings in running a permanent magnet motor is greater than the unit price differential between an induction motor and a permanent magnet synchronous motor.
The hysteresis motor is a well known device. It is widely used in small motor applications. It has simple constructional features with conventional stator windings and a solid rotor hysteresis ring. It has built-in constant torque during the run-up period and it can pull into synchronism any load inertia that it can accelerate. Its starting current is usually less than 180% of the full-load current. Unlike other synchronous motors, it has no preferred synchronizing point and is practically noiseless during operation. These advantages make this motor specially suitable for wide industrial applications and meet the requirements of new adjustable speed drives. As a result, the hysteresis motor is manufactured with new high energy hysteresis materials to improve its performance and rating.
Conventional circumferential-flux-type hysteresis motors are widely used in drives demanding robustness in construction, simplicity in operation, speed constancy, self-starting, high starting and synchronizing torque, low starting current, and low noise. In spite of these advantages, the commercial hysteresis motors still suffer from chronic limitations, e.g. high magnetizing current, low power factor, and low efficiency associated with high parasitic losses. The starting torque of these types of motors is obtained by virtue of the hysteresis effect of the semi-hard permanent magnet material used in the rotor. The maximum torque is dependent on the area of its rotor B-H characteristics. For a fixed excitation, the conventional hysteresis motor torque is constant from start to synchronous speed. Thus the pullout torque is ideally equal to the full-load torque. If the load torque does not exceed the maximum hysteresis torque, the motor runs at synchronous speed in steady state but the angular position of the rotor relative to the stator revolving field is random. On the other hand, a conventional reluctance motor has quite low starting torque but high pullout torque. It also has preferred synchronizing position with respect to the stator revolving field.
The rotor annular ring of a hysteresis motor is normally made of cobalt-steel-type alloys. If such ring can be manufactured as a salient-pole type rotor by designing the rotor to have magnetic saliency with different reluctances on axes mutually at 90.degree. electrical, then the motor would also produce a torque by reluctance motor action in addition to its hysteresis torque. At any speed below the synchronous speed, rotor saliency produces a torque pulsation. When the rotor reaches synchronous speed, it synchronizes in a definite position relative to the stator revolving field. This position is determined by the axes of saliency and load torque. The resultant maximum synchronous torque is the combination of the hysteresis and reluctance effects. Consequently, the pullout torque capacity will be increased when compared to that of the plain hysteresis motor. This type of motor is also known as a polarized hysteresis motor. The unique feature of high starting torque which remains constant up to synchronous speed, makes this hybrid motor particularly suitable for applications in robotics, machine tools, and textile industries, where the precise rotor positioning of the drive is an important requirement.
The hysteresis motors of the prior art, however, have been subject to a number of shortcomings which have limited their application to motors of extremely small power output, for example, of the order of about 1/5000 horsepower, e.g., as are customarily used in synchronous electric clocks. The most important of these shortcomings have been extremely low efficiency, small power output per unit weight and volume, relatively small starting torque, and extremely small synchronizing torque. Certain of these shortcomings can be traced to the fact that it has been generally recognized in the art that hysteresis motors should have a relatively small air gap in order to provide any appreciable starting torque and at the same time avoid the tendency of the motor to lock in at subsynchronous speeds. A large air gap, of course, very materially reduced the magnetic efficiency of the motor.
It is well-known that the hysteresis-reluctance motor produces a torque that is a combination of the hysteresis and reluctance effects. Consequently, the performance characteristics of a hysteresis-reluctance motor would be improved when compared to that of the plain hysteresis motor.
In past designs of hysteresis-reluctance motors, the saliency of the rotor was created by cutting symmetrical slots in the outer surface of the rotor. This, however, caused tooth ripple harmonics, due to the variation of the air gap reluctance. These effects contributed additional flux parasitic losses and noise.
It had been proposed to avoid the last-mentioned disadvantage by decreasing the air gap of the motor to the minimum permitted by manufacturing tolerances and making it uniform throughout the periphery of the rotor and providing a polyphase rotating field of uniform intensity and constant angular velocity by means of a polyphase or split-phase distributed winding, the space-phase displacement of which is equal to the time-phase displacement of its excitation. However, it had been found that, while this relationship would be optimum for an ideal motor having a perfectly sinusoidal flux distribution, as a practical matter the reduction of the air gap below a definite value actually reduced both the starting torque and the running torque of the parasitic hysteresis losses developed by the harmonic flux components due to the armature teeth and slots. These parasitic hysteresis losses increase rapidly as the air gap is decreased. The synchronous hysteresis motors of the prior art have also been subject to the disadvantage that they have had extremely small synchronizing torques, both pull-in torque and pull-out torque.
U.S. Pat. No. 2,041,875 patented May 26, 1936 by H. M. Staller provided a hysteresis synchronous motor having a number of stator windings producing different numbers of poles and a cylindrical shell rotor operating at substantially maximum permeability that shall rotate at a number of synchronous speeds upon selective energization of the stator windings. The patentee provided a slow speed motor adapted to operate at a plurality of synchronous speeds. It included a stator having a slotted core and a plurality of windings wound for different numbers of poles. The rotor included a continuous, symmetrical ring of magnetic material, the windings being disposed in the stator slots at different depths and the thickness of the rotor magnetic material being such as to obtain optimum flux density in the rotor and maximum torque by the motor when either winding is energized. Electrical means shifted the synchronous speed of the rotor at will by energizing any desired stator winding.
U.S. Pat. No. 2,328,743 patented Sep. 7, 1943 by H. C. Roters provided self-starting hysteresis motor comprising stator and rotor elements having coaxial cooperating substantially continuous cylindrical surfaces forming a uniform air gap therebetween and means including a symmetrical distributed exciting winding wound on said stator element for developing a rotating field of constant intensity and angular velocity. The rotor element comprised an annular shell of material having a high hysteretic constant and a supporting spider of low remanence high-permeability material having salient poles with cylindrical faces engaging the shell and equal in number to the stator poles. The spider was effective to develop a substantial variable-permanence synchronizing torque.
U.S. Pat. No. 2,468,295 patented Apr. 26, 1949 by J. M. Hush provided a hysteresis type motor adapted for being driven at synchronous speeds for use as clock or timer motors. The patentee provided an electric motor having a magnetic frame including a plurality of spokes. Rings of magnetic material connected the ends of the spokes and defined an annular space. A rotor including magnetically-retentive material was rotatably suspended in that space. Coils were wound around the spokes for establishing a magnetomotive force across the annular space.
U.S. Pat. No. 2,784,331 patented Mar. 5, 1957 by E. P. Nodemann provided an orienting, self-starting synchronous motor including a polyphase stator member and a rotor member. The rotor member included a shaft, a hysteresis starting element floating on the shaft and a permanent magnet element fixed to the shaft. Means coupled the hysteresis element with the permanent magnet element for synchronously positioning the shaft of the rotor in a repeatable close mechanical reference to the rotating magnetic field vector produced by the stator. The permanent magnetic element had an outside contour to provide two salient poles with no abrupt change in curvature between the poles, thereby providing a large concentration of diametrical flux affording a high degree of orientation.


A polymer composite and its method of manufacture using a recycled multilayer material. An example of the recycled multilayer material is comprised of a polyethylene/polyethylene terephthalate/aluminum film that may be extruded with organic filler to obtain desirable performance in wood-substitute products such as deck boards, railing, fencing, pergolas, residential cladding/siding, sheet products, and other applications.

Exemplary embodiments of the present invention relate generally to composite products and related methods for manufacturing such products. Composite materials can offer many benefits as compared to natural materials such as wood. However, despite many years of development, there is still a need to improve the formulation, manufacturing, and resulting characteristics of composite materials.
Many composite products are made from virgin materials. However, virgin materials may be in limited supply and/or costly. Thus, there is a need to use at least a portion of recycled material in the formulation of a composite. There is also a need to use at least a portion of recycled material for sustainability reasons and also to potentially earn LEED points.
There is also a need to be able to incorporate a wider range of materials into the composite. The ability to use a broader range of materials (including materials such as lubricants, processing aids, etc.) may facilitate the manufacturing of composite products due to the increased availability of suitable materials. For example, it may be desirable to use different types of recycled material including materials with multiple polymer, filler, and additive materials within the recycled material construction, which may not be an option with typical composites. For another example, one particular material in a multilayer construction may be most important, yet it is still desirable to be able to incorporate the other materials in the multilayer construction to allow for more flexibility in material selection. In addition, the increased availability of suitable materials may help to control the cost of the composite product.
A drawback of typical composites using recycled materials is that the physical characteristics of the composites may lack in comparison to the same composites made with virgin materials. For example, characteristics such as coefficient of thermal expansion, modulus of rupture, modulus of elasticity, moisture sensitivity, peak load, and other mechanical characteristics may be adversely impacted by the use of recycled materials in many common composites. With respect to decking products such as deck planks and rails, the reduction of such characteristics may lead to increased sagging or other types of deterioration. Accordingly, there is a need to be able to use recycled materials and still maintain the same or similar physical characteristics relative to comparable virgin materials.
Additionally, there is a need to improve the manufacturability of composite materials to obtain desirable products. For instance, the use of recycled materials may impact the extrudability of the composite material. It may also limit the adhesion of a cap layer to a substrate.
Furthermore, when exposed to the sun, composite materials can become hot to the touch, especially relative to natural wood. As such, there is a need to transfer heat away from a surface of a composite product and/or minimize the static charge of a composite material. In particular, there is a need to transfer heat away from or otherwise cool the surface of composite decking and railing components.
Present exemplary embodiments may satisfy some or all of the aforementioned needs. An exemplary embodiment may use recycled packaging (e.g., juice pouches or other types of aluminized packaging) or other types of multilayer materials (e.g., films) in the production of a polyethylene, polypropylene, other olefin, or ionomer composite to obtain one or more of the aforementioned advantages. Another example may include metal filler in a composite, which may assist with transferring heat away and/or dissipating a static charge from the surface of a composite product. Yet another embodiment may include polyethylene terephthalate (PET). Thus use of PET may, for example, effectively act as a compatibilizer to allow for the incorporation of a wider range of materials into the composite. In some embodiments, PET may also improve the adhesion of a capstock layer to a substrate. Accordingly, examples of recycled packaging or other multilayer materials may include PET and/or a metallic layer such as may be found in recycled beverage pouches or other liquid containers. While PET may be particularly beneficial, other embodiments may include another polyester instead of or in addition to PET. Further embodiments may include improvements in the incorporation of other ingredients and/or in processing conditions to facilitate manufacturing of the aforementioned composites that have the same, similar, or improved physical characteristics relative to a comparable control.
In certain exemplary embodiments, the inventors have overcome a difficulty in using recycled materials, particularly multilayer materials such as recycled packaging (e.g., juice packs and other types of aluminized packaging). Multilayer materials are often for a single use and disposable, which places a burden on landfills that are nearly filled to capacity. In fact, The Freedonia Group has estimated that approximately one-third of all municipal solid waste in the United States consists of discarded packaging. As such, there is a need to be able to reuse discarded packaging, particularly multilayer plastics.
In many multilayer materials, the combined polymer layers are beneficial for packaging such as for barrier properties, but are difficult to re-utilize. Multilayer recycled plastics cannot be readily separated back into the individual components such as high density polyethylene. In the combined form, certain layers melt at different process temperatures than other polymer layers, and some layers such as an aluminum coating do not melt at all at polymer processing temperatures. There has thus been a difficulty in recycling multilayer plastics (e.g., flexible packaging) due to the combination of different materials in the laminate. Enval, which is based in the United Kingdom, uses microwave-induced pyrolysis technology to separate laminate materials into the individual components. However, this technology is costly, time-consuming, and requires an undesirable amount of energy to achieve the separation of the individual components.
In view of these difficulties, it is surprising that the inventors have identified a class of materials and, for example, a particular combination of polyethylene/PET/aluminum film and other polyethylene, polypropylene, olefin, and ionomer multilayer materials, that may be extruded successfully and also provide desirable performance in wood-substitute products that may be used, for example, in deck boards, railing, fencing, pergolas, residential cladding/siding, and other applications.
In addition to the novel features and advantages mentioned above, other benefits will be readily apparent from the following descriptions of the drawings and exemplary embodiments.

This patent is subject to a terminal disclaimer.

Use of recycled packaging in polymer composite products


A programmable dental x-ray inscription system is disclosed for use in physically inscribing developed dental x-rays with patient identifying indicia representative of the identity of the patient, the esposure date of the dental x-ray, the tooth numbers of teeth represented in the x-ray and other related information. The physical inscriptions have a depth dimension into the developed dental x-ray. The programmable dental x-ray inscription system includes a housing which is positionable on a work surface such as a desk or countertop. During the programming cycle of the system, the user places a developed dental x-ray within the projected support tray of the system, which is thereafter retracted within the housing. Then during the programming cycle, user-directed prompts and queries are displayed on the display panel of the system so that the user selects a suitable inscription field and enters data representative of desired patient identifying indicia. Thereafter, the patient identifying indicia is automatically inscribed within the selected inscription fields of the dental x-ray. In the illustrative embodiment, the physical inscription process is achieved using a laser beam generated and scanned within the housing of the system.

1. Field of Invention
The present invention generally relates to automated x-ray marking systems, and more particularly to a programmable dental x-ray inscription system which facilitates permanent marking of developed dental x-rays with patient identifying indicia and other information useful in patient record management and dental insurance claim processing.
2. Brief Description of the Prior Art
The use of x-ray photographs is a long established practice in the dental art. The reason for this is quite clear. Dental x-ray photographs (hereinafter "dental x-rays") provide high-definition visible images of the internal structure of a patient's teeth, permitting early identification of cavities, tooth decay, and other dental diseases which otherwise are not visible to the unaided eye of the dentist. Consequently, the use of dental x-rays in the field of dentistry has become a standard practice, and in many instances, required prior to conducting particular procedures such as, for example, root canal, apicoectomy and extraction.
As with most technological innovations, the social impact of dental x-rays has extended beyond those who primarily use them, namely dentists and oral surgeons. For example, when a patient having dental insurance or a dentist accepting insurance assignment for services rendered, submits a dental claim to the patient's insurance carrier, the insurance carrier typically requires the attending dentist to send dental x-rays taken of those teeth involved in the dental claim. This dental x-ray reporting procedure involves mailing a set of developed dental x-rays from the dentist's office to the insurance company's claim department. Typically, these dental x-rays are held in a dental x-ray folder having slots within which periapical size dental x-rays are held. During this procedure, however, a number of problems frequently occur.
For example, one problem is that in the claims department of the insurance company, the dental x-rays of one patient are often mistaken for the dental x-rays of another patient. This occurs primarily because most dental x-rays are typically unmarked as to patient identity and date of exposure, and also because the developed dental x-rays within dental folders frequently dental fall out during handling and mailing. Consequently, at both the dentist office and dental insurance claim department, dental x-rays are frequently dated incorrectly, mishandled or placed in wrong patient charts or wrong dating envelopes. Thus, when clerks at the insurance company attempt to process submitted dental insurance claims, they are often unable to identify which dental x-rays belong to which patient. Consequently, the claim clerks must frequently request a second set of dental x-rays, causing added expense in claim processing, and further delay in payments to dentists and patients alike.
In an effort to avoid the above-described problems within dental offices and claim departments of insurance companies, a number of prior art approaches have been proposed for marking dental x-rays.
One prior art approach has been to use pens, stickers or labels to mark developed dental x-rays with the name of the patient and the date of exposure of the x-ray. However, such a dental x-ray marking technique suffers from a number of significant shortcomings and drawbacks. In particular, the pen markings on the dental x-ray often smear, and patient identification stickers and labels are easily removed and replaced with new stickers or labels containing false information. Consequently, false dental claim submissions can be easily corroborated using this dental marking technique.
An alternative approach to marking dental x-rays has been proposed in U.S. Pat. Nos. 5,034,974 to Yurosko and 3,846,634 to Fleming. In both of these U.S. Letters Patents, a method is disclosed for photographically marking dental x-ray film with patient identifying indicia, using a light transparent card or band in conjunction with an identification camera. To photographically imprint patient identifying indicia on a selected portion of an exposed dental x-ray, the patient identifying indicia is either typed or written onto the light transparent card. Then, the card is registered with a selected portion of the exposed dental x-ray on which the patient identifying indicia is to be printed. The exposed dental x-ray and card are then loaded into the identification camera, and only a selected portion of the dental x-ray, where imprinting is desired, is exposed to intense light. Thereafter, the exposed dental x-ray is unloaded from the identification camera, the card removed, and the exposed dental x-ray developed using a conventional photographic development process. The result is a dental x-ray which bears a permanent marking indicating the identity of the patient and the date of exposure of the x-ray. While the above-described U.S. Letters Patents disclose a way and means to permanently mark exposed dental x-rays, this prior art approach suffers from significant shortcomings and drawbacks. In particular, this technique is manually intensive, time-consuming and generally prone to errors in marking. In addition, it involves handling exposed dental x-ray photographs during the photographic marking process, and thus requires working in a dark-room environment.
Thus, there is a great need in the dental art and insurance industry for a method and apparatus for permanently marking developed dental x-rays with patient identifying indicia, while overcoming the shortcomings and drawbacks associated with prior art methodologies and apparatus.

Programmable dental x-ray inscription system and method of processing dental insurance claims using same


A circuit arrangement for automatic distortion correction of a signal transmitted over a line having low-pass filter characteristics, employs a distortion corrector having a controllable high-pass filter and a controllable-gain amplifier. The distortion corrector includes the high-pass filter with a predetermined frequency characteristic and a first attenuator connected in series therewith in a first branch, and a two-terminal network of a predetermined frequency characteristic in a second branch. The controlled-gain amplifier includes a second attenuator and an amplifier connected in series therewith which effects a predetermined amplification. The current/voltage characteristics of the first and second attenuators are substantially identical and their attenuation depends on a signal which is derived from the distortion-correct signal by means of rectification and smoothing.

1. Field of the Invention
The present invention relates to a circuit arrangement for automatic distortion correction of a signal which has been transmitted over a line having low-pass filter characteristics and which is fed to a distortion corrector having a controllable high-pass filter and a controllable-gain amplifer. As an example, the line can be a two-wire circuit of a local cable.
2. Description of the Prior Art
As is well known in the art, the level of a signal is lowered all the more after transmission by way of a line, with respect to the length of the line. At the same time, all frequency components and, particularly the high-frequency components, of the signal are attenuated all the more, the longer the line. Therefore, the low-pass filter behavior of the line is all the more pronounced with increasing line length. As is known in the art, a distortion-corrected signal is desired whose level and whose frequency characteristic is constant and independent of the length of the line.
For automatic distortion correction of a signal, as is known in the art, the signal to be corrected can be transmitted by way of a controllable high-pass filter and by way of a controllable-gain amplifier, whereby, as a function of the output signal of the controlled-gain amplifier, a control voltage is derived with which both the high-pass behavior of the high-pass filter, as well as the amplification of the controllable-gain amplifier, can be regulated in such a manner that a distortion-corrected signal is delivered at the output of the control-gain amplifier. Circuit arrangements known in the art which effect such an automatic distortion correction of the signal require a relatively large technical expense and a large expense with respect to time in order to match the various control loops of the high-pass filter and of the controlled-gain amplifier to one another and adapt the same to the low-pass filter characteristic of the line.

Circuit arrangement for automatic distortion correction of a signal


A method is specified for operating a rotating electrical machine, in which the rotating electrical machine is connected in terms of phase to a converter circuit, having a DC voltage circuit, for connecting at least two voltage levels, and the phases of the converter circuit are connected to the DC voltage circuit in accordance with a selected switching state combination of switching states for power semiconductor switches in the converter circuit. In order for operation of the rotating electrical machine to be possible in an event, over a number L of sampling times various values are determined, and a switching state combination is set as the selected switching state combination with which a sum of determined values is at its smallest.

High-power voltage converter circuits are used in many applications today. Such a converter circuit usually connects three voltage levels and is often used for operating rotating electrical machines, in particular in synchronous and asynchronous machines, which rotating electrical machines generally have three stator windings. In a conventional method for operating a rotating electrical machine, it is connected in terms of phase to such a converter circuit, having a DC voltage circuit, for connecting generally m voltage levels, where m≧2. In the case of a converter circuit for connecting typically three voltage levels, the DC voltage circuit is formed by a first capacitor and by a second capacitor which is connected in series with the first capacitor, the DC voltage circuit also having a first main connection at the first capacitor, a second main connection at the second capacitor and a subconnection formed by the two series-connected capacitors. Furthermore, the converter circuit for connecting three voltage levels comprises power semiconductor switches, which are generally interconnected. In relation thereto, FIG. 1 shows an embodiment of a known three-phase converter circuit for connecting three voltage levels. According to the method, the phases of the converter circuit are generally connected to the DC voltage circuit in accordance with a selected switching state combination of switching states for the power semiconductor switches in the converter circuit. In the case of a converter circuit for connecting three voltage levels, the phases of the converter circuit are accordingly connected to the first main connection, to the second main connection or to the subconnection according to a selected switching state combination of switching states for the power semiconductor switches in the converter circuit. In a state diagram shown in FIG. 2, these switching state combinations and their transitions with respect to one another are shown, the "+" representing a connection of the corresponding phase to the first main connection, "−" representing a connection of the corresponding phase to the second main connection and "0" representing a connection of the corresponding phase to the subconnection.
The selection of the corresponding switching state combinations takes place, for example, according to the known "direct torque control" (DTC) method, in which the latest actual value for the torque of the rotating electrical machine, the magnetic stator flux of the rotating electrical machine and the potential at the subconnection are initially in each case compared with an associated predetermined value range. The respectively predetermined value range is or can be time-variant and is usually determined by an upstream closed-loop control circuit from reference values for the torque of the rotating electrical machine, the magnetic stator flux of the rotating electrical machine and the potential at the subconnection. If a latest actual value now exceeds its associated predetermined value range, a switching state combination is selected from a table as a function of the preceding selected switching state combination such that the latest value resulting for this switching state combination could, if need be, again be within the associated value range, this not being guaranteed. In addition, a switching state combination is always only selected either with respect to the latest actual value for the torque, the magnetic stator flux or the potential when the associated value range is exceeded. The latest actual value for the torque, the magnetic stator flux and the potential is not considered jointly.
One problem with a method described above for operating a rotating electrical machine by means of the known "direct torque control" is the fact that there are typically a plurality of transitions between the preceding selected switching state combination and the latest selected switching state combination, these transitions being illustrated in FIG. 2 as lines between the switching state combinations. The switching state combinations and the transitions from one switching state combination to another are generally stored permanently in the table, in which case typically not all of the combination possibilities for the switching state combination are stored in the table, as shown in FIG. 2. Furthermore, in the case of "direct torque control", only one switching state combination is selected as a function of the preceding selected switching state combination with the associated transitions, which is stored in the table and which brings the latest value resulting for the selected switching state combination back to within the associated value range again. Switching state combinations to be selected as an alternative, in particular with possibly fewer transitions to the preceding selected switching state combination, are not stored in the table. A plurality of transitions between switching state combinations do generate, however, a large number of switching operations for the power semiconductor switches in the converter circuit, as a result of which the switching frequency of the power semiconductor switches is increased. However, such a high switching frequency produces heat loss (a higher energy consumption) in the power semiconductor switches in the converter circuit, as a result of which heat loss the power semiconductor switches age more quickly and may be damaged or even destroyed.
In this regard, EP 1 670 135 A1 specifies a method for operating a rotating electrical machine by means of which the switching frequency of power semiconductor switches in a converter circuit, which is connected in terms of phase to the rotating electrical machine, for connecting m voltage levels can be reduced, where m≧2. In accordance with the method, in one step (a) the phases of the converter circuit are connected to the DC voltage circuit in accordance with a selected switching state combination of switching states for power semiconductor switches in the converter circuit. The selection of this switching state combination takes place in the following further steps:    (b) beginning with a starting sampling time k for a selectable number N of sampling times: determination of all the switching state combinations at each of the N sampling times, where N≧1,    (c) formation of switching state sequences for each determined switching state combination at the starting sampling time k, each switching state sequence being an arrangement of determined switching state combinations of the N sampling times next to one another in a row, said switching state combinations being associated with the respective switching state combination at the starting sampling time k,    (d) for each of the switching state sequences, calculation of a torque trajectory of the rotating electrical machine and a magnetic stator flux trajectory of the rotating electrical machine from determined state value sets of the rotating electrical machine and the converter circuit for the starting sampling time k up to the sampling time k+N,    (e) selection of a switching state sequence, in which an associated torque trajectory and a magnetic stator flux trajectory at the (k+N)-th sampling time is in each case within a predetermined value range and setting of this selected switching state sequence,    (f) repetition of steps (a) to (d), where k=k+1.
In the method for operating a rotating electrical machine in accordance with EP 1 670 135 A1, only one switching state combination is selected and set, in which the associated torque trajectory and the associated magnetic stator flux trajectory at the (k+N)-th sampling time is in each case within a predetermined value range. However, it is possible for the torque trajectory or the magnetic stator flux trajectory of each associated switching state combination to already be outside the predetermined value range at the k-th or at the (k+1)-th sampling time, and the method for operating a rotating electrical machine in accordance with EP 1 670 135 A1 cannot handle such a state. Therefore only a restricted operation of the rotating electrical machine is possible, however.

Method for operating a rotating electrical machine


Methods for recovering gold from gold-bearing materials are provided. The methods rely upon on the self-assembly of KAuBr4 and α-cyclodextrin (α-CD) in aqueous solution to form a co-precipitate, a 1:2 complex, KAuBr4•(α-CD)2 (“α•Br”), either alone or in an extended {[K(OH2)6][AuBr4]⊂(α-CD)2}n chain superstructure (FIG. 1). The co-precipitation of α•Br is selective for gold, even in the presence of other metals, including other square-planar noble metals. The method enables one to isolate gold from gold-bearing materials from diverse sources, as further described.

Considerable interest exists in methods for recovering gold from gold-bearing materials. Besides the obvious economic incentives associated with gold being a precious metal, environmental motivations justify extracting gold from certain gold-bearing waste materials (for example, consumer electronics).
A common method for gold recovery uses a cyanide leaching process in which highly poisonous inorganic cyanides convert gold(0) into a water-soluble Au(CN)2-coordination complex, which is subsequently isolated using cementation, absorption, or solvent extraction as typical methods. The cyanide leaching process for gold recovery is undesirable, as accidental leakages of cyanide result in environmental contamination and inadvertent cyanide exposure to those who conduct the process causes needless human health concerns. Accordingly, developing processes for gold recovery using environmentally benign chemistry is not only important from a green chemistry perspective, but such efforts may also lead to health benefits for the processing workers.


In a matched filter, a spread data path unit holds inputted spread data, a multiplier unit multiplies an output of the spread data path unit by a spreading replica code, and an adder unit adds results of the multiplication and outputs an added result. The spread data path unit comprises a first selector being able to selectively output the spread data, a plurality of sub spread data path units each having a plurality of latch circuits temporarily holding the spread data from the first selector, and a second selector being able to selectively output outputs from the sub spread data path units, whereby a circuit scale of the spread data path unit is decreased.

(1) Field of the Invention
The present invention relates to a matched filter suitable for use in a radio receiver adopting direct sequence code division multiple access.
(2) Description of Related Art
In direct sequence code division multiple access (DS-CDMA [Direct Sequence Code Division Multiple Access]), the transmitter primarily modulates a data code in, for example, QPSK (Quadrature Phase Shift Keying), spreads a bandwidth thereof using a spreading code, and transmits the data code. On the other hand, the receiver cross-correlates using the same spreading code as in the transmitter to detect a peak of the correlation value, performs acquisition and tracking, and demodulates by correlation detection.
FIG. 11(a) is a block diagram of a transmitting unit of a radio terminal in DS-CDMA using QPSK. In the transmitting unit 30 of the radio terminal in DS-CDMA shown in FIG. 11(a), a data code is QPSK-modulated in a primary modulating unit 30a, a bandwidth of the signal is spread with an PN code (Pseudo Noise Code) in a spreading modulating unit 30b, an output of the spreading modulating unit 30b is up-converted in a frequency converting unit 30c, a power thereof is amplified in an RF amplifying unit 30d, and a radio signal is sent out to a radio propagation path from an antenna 30e.
FIG. 12 is a diagram showing a relationship among a data code, a spreading code and a transmit code when the data is spread using QPSK in the primary modulation. Data codes Di and Dq are complex-multiplied by spreading codes Ci and Cq in multipliers 36a, 36b, 36c and 36d, and obtained results are added in adders 37a and 37b and outputted as transmit codes Si and Sq The complex-multiplication signifies an operation [(Di+jxc2x7Dq)xc2x7(Ci+jxc2x7Cq) with the date codes Di and Dq and the spreading codes CI and Cq, where j represents an imaginary unit (j2=xe2x88x921).
Next, a receiving system will be described. FIG. 11(b) shows a block diagram of a receiving unit of the radio terminal in DS-CDMA using QPSK. In the receiving unit 31 of the radio terminal in DS-CDMA, a weak radio signal whose bandwidth has been spread is received by an antenna 31a, the radio signal is amplified with a low noise in an RF amplifying unit 31b, an output of the RF amplifying unit 31b is down-converted in a frequency converting unit 31c. Further, the signal down-converted in the frequency converting unit 31c and a spreading replica code generated inside the receiving unit 31 are band-cross-correlated in a despread demodulating unit 31d, a narrow-band signal is thereby taken out, and an output of the despread demodulating unit 31d is QPSK-demodulated in a primary demodulating unit 31e.
FIG. 13 is a diagram showing a detailed structure of the receiving unit 31 of the radio terminal in DS-CDMA using QPSK. As shown in FIG. 13, a flow of the signal in the frequency converting unit 31c, the despread demodulating unit 31d and the primary demodulating unit 31e is as follows. Namely, an I channel signal is mixed with an output of a local oscillator 38b in a frequency converting unit 38a, whereas a Q channel signal is mixed with an output of a 90xc2x0 phase shifter 38c in a frequency converting unit 38d. Outputs of the frequency converting units 38a and 38d are converted from analog to digital in A/D (analog/digital) converters 39a and 39b. These digital signals are branched and inputted to despread demodulating unit 40. In four matched filters in the despread demodulating unit 40, the signals are band-cross-correlated, an output of a matched filter 40a and an output of a matched filter 40d are added, in an adder unit 41a, whereby I channel data Si is outputted. In a similar manner, a signal obtained by inverting an output of a matched filter 40b and an output of a matched filter 40c are added in an adder unit 41b, Q channel data Sq is thereby outputted. These outputs are QPSK-demodulated in a post-demodulation processing unit 42.
Next, band-cross-correlation in the despread demodulating unit 40 will be described. The despread demodulating unit 40 generates spreading replica codes Ci and Cq in the same sequence as on the transmitter""s side to perform despreading, which comprises the matched filters 40a, 40b, 40c and 40d. When the two spread codes are cross-correlated, each of the I channel component and the Q channel component is despread two times, four times in total. In the matched filters 40a, 40b, 40c and 40d, M(nt) in the following formula (1) is computed.
M(nt)=xcexa3Tk=1R(k)xc2x7P(nt)xc2x7Zxe2x88x92kxe2x80x83xe2x80x83(1)
Where t is a chip duration, T is the number of taps, R is a spreading replica code, k and n are integers, P(nt) is a received spread code, and Z is a complex number in Z transform. One chip duration t represents a time for which the spread code is switched, designed to be a time of speed several tens to several hundreds times one bit duration. One chip duration t is a reciprocal of a chip rate. The number of taps T represents a length of a spread code. A length of the spread code is, for example, 256 bits, but there can be used a different spread code of, for example, 128 bits or the like. The received spread code P(nt) and the spreading replica code R(k) of 256 bits are EXORed, a result of this is shifted at the chip rate, added and outputted. Accordingly, an output signal Di of the A/D converter 39a and an output signal Ci of a spreading replica code generator 44a are cross-correlated in the matched filter 40a. In the similar manner, an output signal Di of the A/D converter 39a and an output signal Cq of the spreading replica code generator 44a are cross-correlated in the matched filter 40b, an output signal Dq of the A/D converter 39b and an output signal Ci of the spreading replica code generator 44a are cross-correlated in the matched filter 40c, and an output signal Dq of the A/D converter 39b and an output signal Cq of the spreading replica code generator 44a are cross-correlated in the matched filter 40d. A reason why the number of the matched filter is four is to-prevent degradation of an S/N (Signal/Noise) ratio of a despread signal.
Such a matched filter is a key device necessary to despread a received spread code, there is hence required a low power thereof. FIG. 14 is a diagram showing a block structure of the matched filter. The matched filter 40a (40b, 40c or 40d) shown in FIG. 14 cross-correlates a digital signal outputted from the A/D converter 39a or 39b shown in FIG. 13 with a spreading replica code generated inside the receiving unit 31, thereby despreading the signal. The matched filter 40a (40b, 40c or 40d) comprises a spread data path unit 43, a spreading replica code generator 44a, a register for replica code 44b, a multiplier unit 45 and an adder unit 46. The spread data path unit 43 is a shift register that captures a received spread code input at each clock and shifts the code one stage by one stage, which comprises T flip-flops (FF) 43-1, 43-2, 43-3, . . . 43-(Txe2x88x922), 43-(Txe2x88x921) and 43-T. Hereinafter, the flip-flop will be abbreviated as FF occasionally. The spreading replica code generator 44a generates a spreading replica code identical to one used in the transmitter. The register for replica code 44b is a register for computing the spreading replica code generated by the spreading replica code generator 44a. The multiplier unit 45 multiplies each of outputs of the flip-flops 43-1, 43-2, 43-3, . . . , 43-(Txe2x88x922), 43-(Txe2x88x921) and 43-T with each output of the register for replica code 44b. The adder unit 46 adds outputs from the multiplier unit 45 and outputs an added result. Each of the multiplier unit 45 and the adder unit 46 has the number of taps T, to which a clock at the chip rate is inputted. In FIG. 14, the number of spread data path bits represents the number of bits equal to a modulation multivalue in the primary modulation. In this case, the number of spread data path bits is 6. The received spread code signifies that one symbol is received with 6 bits. Therefore, a total number N of the necessary flip-flops is given by N=Dxc3x97T, where D is the number of spread data path bits and T is the number of taps of the flip-flops.
This circuit is an example where the number of times of over-sampling is 1, so that sampling is performed once during one chip duration. The flip-flops are therefore in T stages equal in number to a length of the spread code. When the over-sampling is performed plural times within one chip duration, the operation is performed plural times equal to the number of times of over-sampling within one chip duration. In the case of four-times over-sampling, for example, the sampling is performed four times within one chip duration on a spread code of 256 bits. The number of stages of the flip-flops M is given by M=Txc3x97O, where T is the number of taps T and O is the number of times of over-sampling. Accordingly, a total number N of necessary flip-flops is given by N=Dxc3x97M, where D is the number of spread data path bits and M is the number of stages of the flop-flops.
FIG. 15 is a functional block diagram of the matched filter. It is only necessary to hold a received spread code (spread data input) consisting of plural bits shown in FIG. 15 for one cycle in the sp read data path unit 43, it being unnecessary to shift the spread code. One cycle of the spread code is a time for which the received spread code is held, corresponding to a life time of P(nt). This cycle U is expressed as U=[(one chip duration)xc3x97(the number of taps T)]. The operation of the formula (1) is performed in the multiplier unit 45 and the adder unit 46, and can be performed in any portion without limitations on the order or positions of operators since the operation does not rely on results of operations performed before and after. Further, since the contents of the operation on any received spread code is quite the same, it is seen that the operation is xe2x80x9csymmetricalxe2x80x9d. With the matched filter, initial acquisition can be very quickly, and a process up to despreading can be completed once. The matched filter has futures {circle around (1)} through {circle around (4)} below.
{circle around (1)} operating at a frequency equal to or greater than a chip rate (in the case of over-sampling);
{circle around (2)} since the spreading data path unit is generally configured with a shift register, all the flip-flops always operate;
{circle around (3)} in order to certainly hand data to be shifted, a flip-flop of a master/slave type in two stages is used as the flip-flops configuring the shift register;
FIG. 16(a) is a diagram showing a structure of the shift register in which flip-flops of a master/slave type are used. FIG. 16(b) is a diagram showing an example of a structure of the flip-flop of a master/slave type in two stages. A clock terminal of the master FF and a clock terminal of the slave FF are given signals inverted to each other. FIG. 16(c) is a diagram for illustrating an operation of the flip-flop of a master/slave type in two stages. An input signal is stored at a posiedge clock, and the stored input signal is outputted at a negaedge clock shown in FIG. 16(c).
{circle around (4)} in the case of QPSK, four matched filters are basically required in order to separate into I channel and Q channel.
However, these futures conversely cause the following problems. Namely, these futures causes an increase of power consumption ({circle around (1)}) since the device operates at a high frequency, an increase of the number of flip-flops to be operated ({circle around (2)}), and an increase of circuit scale of the spread data path unit ({circle around (3)} and {circle around (4)}) further, from {circle around (2)} to {circle around (4)}, an increase of scale of the circuit because of the long shift register and adder. Moreover, since a switching activity in the spread data path unit is very high, the power consumption is increased.
Some of inventors of this invention have proposed a structure of a ring register in substance in the following publication.
Ben CHEN and Hideto FURUKAWA, xe2x80x9cA Low Power Consumption Digital Matched Filter Design for Wideband DS-CDMAxe2x80x9d, The Institute of Electronics, Information and Communication Engineers, 1998, xe2x80x9cTechnical Group of Circuits and Systems (CAS)xe2x80x9d Work Shop (Apr. 20 and 21, 1998).
FIG. 17 is a schematic block diagram of a matched filter 50 disclosed in the above publication. A received spread signal is stored in one of FFs in a spread data path unit 51b designated by a spread data input control unit 51a. Incidentally, the number of the FFs shown in FIG. 17 is equal to [(the number of taps)xc3x97(the number of times of over-sampling)]. A position designated by the spread data input control unit 51a is cyclically changed at each clock. The stored code is held in the register for only one cycle, shifting being not at all performed. In a multiplier unit 51c having multipliers having the same number [(the number of taps)xc3x97(the number of times of over-sampling)], a spreading replica code generated in its own station is shifted at each clock to perform EXOR operation, and a result of the operation is outputted from an adder unit 51d, whereby computation of despreading is completed.
FIG. 18. is a diagram conceptually showing circuit structures of the spread data input control unit 51a and the spread data path unit 51b, illustrating that circuit structures are conceptually ring. xe2x80x9cRingxe2x80x9d means that a position at which data is held in the spread data path unit 51b is cyclically changed. In other words, xe2x80x9cringxe2x80x9d means a cyclical circuit structure in which a received spread code is stored in a flip-flop at the tail of the shift register circuit, the next received signal is then stored in a flip-flop in the front of the shift register circuit. In this sense, the register circuit for storing (plural bits) is in a ring structure. Note that this does not mean a physical ring circuit arrangement.
FIG. 19 is a diagram showing a structure of the spread data input control unit 51a. A shift register circuit 52 shown in FIG. 19 is a circuit called a round robin ring, configured with [(the number of taps)xc3x97(the number of times of over-sampling)] flip-flops connected to one another. An output of a flip-flop at the tail of the shift register circuit 52 is inputted to a flip-flop at the head of the shift register circuit 52, so that the shift register circuit 52 is in the ring structure as well as the above circuit.
In the round robin ring, only one flip-flop indicates the state xe2x80x9c1xe2x80x9d, the remaining flip-flops are all kept in the state xe2x80x9c0xe2x80x9d, and the flip-flop in the state xe2x80x9c1xe2x80x9d is successively shifted at each sampling clock. Outputs of these flip-flops are connected to flip-flops of the spread data path register circuit 51b in the next stage, neither more or less. Only a flip-flop in the spread data path register circuit 51b connected to the flip-flop in the round robin ring whose state is xe2x80x9c1xe2x80x9d captures a received spread code. As this, a position in which a received spread code is stored is cyclically changed. In the spread data input control circuit 51a, a flip-flop in operation is always one, so that the switching activity is largely decreased, the power consumption is thus effectively decreased.
However, each of the spread data path register circuit 51b and the round robin ring (shift register circuit 52) is configured with flip-flops in 1024 stages simply connected to one another. For this, the circuit is excessively concentrated from a viewpoint of circuit structure or layout, so that the layout becomes impossible.
In the light of the above problems, an object of the present invention is to provide a matched filter, in which the spread data path unit is divided into sub spread data path units equal in number to the number of times of over-sampling so as to decrease a circuit scale of the spread data path unit, each of the sub spread data path units is configured with latch circuit so as to further decrease the circuit scale, each of the sub spread data path units uses an independent clock so as to decrease frequencies of circuit operation, a code load register always recognizes the leading position of a spread code so that the spread code can be instantaneously switched, and a dynamic mask is served to cope with a multi-tap spread code, whereby the switching activity and the circuit scale of the whole circuit of the matched filter is effectively decreased.
The present invention therefore provides a matched filter comprising a spread data path unit comprising a first selector being able to selectively output spread data, a plurality of sub spread data path units each comprising a plurality of latch circuits temporarily holding the spread data from the first selector, and a second selector being able to selectively output outputs from the sub spread data path units, a spread data path input control unit comprising a selector control unit for performing a selection control on the first selector and the second selector according to an input of the spread data, and a data holding control unit for performing a data holding control on the sub spread data path units, a spreading code setting unit being able to set a spreading code, and an arithmetic unit for multiplying an output from the spread data path unit by the spreading code from the spreading code setting unit, adding results of the multiplication and outputting a result of the addition.
Accordingly, with the above structure, the wiring becomes simpler, and excessive concentration of the circuits can be avoided. Since the huge spread data path unit is divided, not a high-speed clock but a low-speed clock can be used so that the power consumption can be decreased. Further, the switching activity and the circuit scale of the whole circuit of the matched filter can be effectively decreased.
The above spread data path unit may comprise sub spread data path units equal in number to the number of times of over-sampling, and each of the sub spread data path units may be configured with latch circuits equal in number to taps.
It is thereby possible to take out the contents at one clock, which is advantageous with respect to speed. It is also possible to reduce a scale of the whole circuit since a shift register causing an increase of the circuit scale is not used.
The data holding control unit may comprise a round robin ring in which finite-state holding units equal in number to the taps are arranged in a ring, and states of the finite-state holding units equal in number to the taps are successively changed at a chip rate such that a state of only one finite-state holding unit among the finite-state holding units equal in number to the taps differs from a state of the other finite-state holding units, so that data holding to the latch circuits configuring each of the sub spread data path units is updated in a predetermined order.
Accordingly, with the above structure, the layout becomes easy and wasteful switching can be avoided, since [(the number of times of over-sampling)xc3x97(the number of taps)] shift register circuit that is huge is not used.
The above selector control unit may comprise a phase counter for generating plural kinds of phase state signals within one chip duration and cyclically outputting the phase state signals, and the first selector may cyclically give inputted spread data to the sub spread data path units in synchronism with the different kinds of phase state signals from the phase counter, whereas the second selector may select one output among outputs of the sub spread data path units and output the selected output in synchronism with a corresponding one of the different kinds of phase state signals from the phase counter. The different kinds of phase state signals may correspond to phase states equal in number to the number of times of each over-sampling.
Accordingly, the layout of the circuit becomes easier, and wasteful switching can be avoided, since a huge shift register circuit is not used.
The above spreading code setting unit may set plural kinds of spreading codes in order to cope with plural kinds of spread code lengths. The spreading code setting unit may comprises code register for holding the spreading code for operation and a code load register being inputted thereto a control signal from the outside to load the next spreading code while the arithmetic unit operates, and the code load register may update contents at a predetermined position of the code register at a predetermined timing. The code load register may be inputted thereto an enable/disable signal controlled from the outside to capture the next spreading code when the enable/disable signal is enable, while not capturing when the enable/disable signal is disable, and be controlled by an algorithm updating contents at the leading position of the code register in synchronism with the code register.
Accordingly, with the above structure, it is possible to cope with an instantaneous switching of the spread code even if the spread code or the number of taps in use is changed.
The above spreading code setting unit may comprise a code register for holding the spreading code for operation and a code load register being inputted thereto a control signal from the outside to load the next spreading code while the arithmetic unit operates, a multi-tap control unit may be disposed on the multiplied output""s side of the arithmetic unit in order to cope with plural kinds of spreading codes, the multi-tap control unit may comprise a mask ring comprising finite-state holding units not less in number than applied taps, and a logical product of an output of each of the finite-state holding units of the mask ring and a multiplied output of the arithmetic unit is outputted to an adder unit of the arithmetic unit.
Accordingly, with the above structure, it is possible to cope with different kinds of spread code lengths with one matched filter, so that it is possible to track the data even if an optional specification is added to the system, and a degree of freedom in designing is increased.
In the mask ring, continuing finite state holding units equal in number to the taps among the finite-state holding units may hold the same state so that a state thereof differs from a state of the other finite-state holding units, and the leading position in the mask ring may be shifted in synchronism with the code register. The multi-tap control unit may be inputted thereto a spread code identify signal that can be controlled from the outside.
Accordingly, with the above structure, the leading position in the mask rings is shifted in synchronism with the code register so that data tracking is possible.
The present invention also provides a matched filter comprising a spread data path unit comprising a plurality of sub spread data path units in each of which a plurality of latch circuits are arranged in order that spread data is inputted thereto, a spread data path input control unit for performing a data holding control to the latch circuits, in a predetermined order according to an input of the spread data, a spreading code setting unit being able to set a spreading code, and an arithmetic unit for multiplying an output from the spread data path unit by the spreading code from the spreading code setting unit, adding results of the multiplication and outputting a result of the addition.
Accordingly, with the above structure, the wiring becomes simple and excessive concentration of the circuit can be avoided, as well. Since the hug spread data path unit is divided, it becomes possible to use a low-speed clock in lieu of a high-speed clock, which leads to a decrease of frequencies of the circuit operation. Further, the switching activity and the circuit scale of the whole circuit of the matched filter are effectively decreased.


A new and improved overhead door apparatus is provided for a structure, such as an enclosed trailer or enclosed truck body, and includes a pair of guide channel assemblies connected to a pair of sidewalls of the structure a predetermined distance from the floor of the structure. A pair of central pivot assemblies are connected to the pair of sidewalls. The central pivot assemblies are located on the pair of sidewalls at locations between the pair of guide channel assemblies and the floor. A rigid unitary door panel assembly which contains an interior X-frame assembly includes a pair of top corners, a pair of bottom corners, and a pair of sides separating the pair of top corners from the pair of bottom corners. The pair of top corners of the door panel assembly includes a pair of roller assemblies adapted to roll along the pair of guide channel assemblies. A pair of first extensible and retractable assemblies are pivotally connected between the pair of top corners of the door panel assembly and the pair of central pivot assemblies. A pair of second extensible and retractable assemblies are pivotally connected between the pair of bottom corners of the door panel assembly and the pair of central pivot assemblies. One of the pair of door panel sides, one of the pair of first extensible and retractable assemblies, and one of the pair of second extensible and retractable assemblies form three sides of a triangular structure.

1. Field of the Invention
The present invention relates generally to doors installed on enclosed trucks or trailer and, more particularly, to truck and trailer doors that are adapted for opening by being moved to a position above the door threshold.
2. Description of the Prior Art
Doors for enclosed trucks, and especially enclosed trailer doors, are often doors that are adapted for opening by being moved to a position above the door threshold. Such overhead doors are generally comprised of a plurality of articulated panel units that have laterally located rollers that ride in laterally located channels as the overhead door is opened and closed. The panels are connected to each other by hinges. Each channel has a vertical portion for keeping the articulated panels in a vertical orientation when the door is closed. Also, each channel has a horizontal portion for retaining the articulated panels in a horizontal orientation when the door is open. Unfortunately, with this type of overhead door, rollers and hinges for the articulated panels are highly susceptible to wear and tear and often need repair or replacement. In this respect, it would be desirable if an overhead door were provided for an enclosed truck or trailer that does not include a plurality of articulated panels connected together by hinges. Also, it would be desirable if an overhead door were provided for an enclosed truck or tr28 ailer which does not include a plurality of rollers associated with each of a plurality of articulated door panels.
The most important factors causing the wear and tear of the hinges of the articulated door panels and the lateral rollers are the vibrations and the road shocks that are transmitted to the stack of door panels and the rollers for each door panel when they are in the vertical portions of the lateral roller channels when the truck or trailer is in motion. Much of such vibration and road shock damage to the overhead door could be reduced or eliminated if the vertical stack of hinged door panels and the vertical stack of lateral rollers could be eliminated. In this respect, it would be desirable if an overhead door were provided for an enclosed truck or trailer that did not include a vertical stack of hinged door panels and did not include a vertical stack of lateral rollers.
In structures that bear stresses and strains, it is well known that the triangle is an excellent structural form for withstanding stresses and strains. In this respect, it would be desirable if an overhead door were provided for an enclosed truck or trailer that employed triangular construction forms.
Another contributing factor to damage experienced by an overhead door for a truck or trailer is the weight of the overhead door. A heavy overhead door tends to experience considerable vibration and road shock damage due to large inertial forces engendered by the heavy weight of the door. To lessen damage of vibration and road shock to an overhead door, it would be desirable if the overhead door were lightweight.
Lifting an overhead door for a truck or trailer may require considerable effort. The door must be lifted against the pull of gravity. To lessen the lifting effort, it would be desirable if the overhead door contained components which provide a lifting force to assist a person in lifting the overhead door.
Throughout the years, a number of innovations have been developed relating to doors for containers, such as tracks and trailers, and the following U.S. patents are representative of some of those innovations: U.S. Pat. Nos. 3,596,403; 3,934,635; 3,950,894; 4,057,170; and 5,016,393. More specifically, U.S. Pat. Nos. 3,596,403 and 4,057,170 disclose trailer doors that open sideways, not overhead. Such side opening doors require two doors at the back of each trailer, one door for the left side and one door for the right side. To avoid the complexity of two doors, it would be desirable if only one truck or trailer door were employed.
U.S. Pat. No. 3,934,635 discloses an overhead door for a trailer that employs a plurality of hinged door panels that have laterally disposed rollers as described above. In addition, the panels are counterbalanced by a spring which is wound by gears that cooperate with racks on the horizontal portions of the tracks on which the panels are movably supported. Although the use of a counterbalancing device is desirable, the use of gears which cooperate with racks may not be. Rotating gears present structures that need be periodically lubricated and may be prone to squeaking if not properly lubricated. In this respect, it would be desirable if an overhead door were provided for an enclosed truck or trailer which provided counterbalancing without the use of gears.
U.S. Pat. Nos. 3,950,894 and 5,016,393 may be of interest for their disclosure of particular door constructions. However, none of the doors disclosed in these patents are for overhead doors for trucks or trailers.
Thus, while the foregoing body of prior art indicates it to be well known to use overhead doors for trucks and trailers, the prior art described above does not teach or suggest a overhead door apparatus which has the following combination of desirable features: (1) does not include a plurality of articulated panels connected together by hinges; (2) does not include a plurality of rollers associated with each of a plurality of articulated door panels; (3) does not include a vertical stack of hinged door panels and does not include a vertical stack of lateral rollers; (4) employs triangular construction forms; (5) is lightweight; (6) contains components which provide a lifting force to assist a person in lifting the overhead door; (7) employs only one door panel; and (8) provides counterbalancing of a single door panel without the use of gears. The foregoing desired characteristics are provided by the unique overhead door apparatus of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.


A fastener for securely fastening a plurality of members having a sleeve with a generally tubular portion and a flange extending radially from one end of the tubular portion and having a mandrel with an enlarged head and a generally cylindrical stem, the stem having a grooved locking section in which the locking groove has a longitudinal component and an adjacent tapered section containing a breakneck groove, the tapered section tapering radially outward toward the mandrel head and ending in a shoulder having an outer diameter signal to or greater than that of the locking section to provide a surface for improved retention of the mandrel with respect to the sleeve when the fastener is installed.

This invention relates in general to fasteners, and more invention relates in general to fasteners, and more particularly to an improved fastener mandrel and method for securing the fastener mandrel with relation to the fastener sleeve.
A blind rivet is generally composed of two pieces. The first piece is the mandrel, which is composed of a cylindrical stem having an enlarged head at one end. The second piece is the sleeve, a generally tubular member surrounding a portion of the mandrel stem and abutting the mandrel head, with an outwardly protruding flange at the end opposite the mandrel head.
In use, such a fastener is typically placed in the pulling head of the powered fastener installation device and directed to the workpiece, which commonly consists of a plurality of members to be fastened. In other instances, the fastener is placed in the workpiece and the powered fastener installation device is then applied to it. In either case, the stem of the fastener is gripped by the jaws of the fastener installation device pulling head, which is then operated by hydraulic pressure to clamp the jaws radially about the fastener stem and pull the stem rearward away from the workpiece. At the same time, a reactive force is applied to the sleeve flange, urging it forward against the workpiece. The tension on the stem pulls the stem head against the sleeve, thereby upsetting the sleeve.
Once the sleeve has been upset, the sleeve flange and mandrel head clamp the members of the workpiece together. After the fastener sleeve is upset in the manner described above, and the workpiece members are clinched together, resistance to the stem movement, and thus tension in the stem, increases under the continued application of the pulling force.
Continued application of a compression load on the sleeve flange causes the bore of the sleeve to constrict as material flows inward toward the mandrel stem. The sleeve material that flows inward into the locking grooves creates an interference fit that inhibits withdrawal of the mandrel from the sleeve.
The stem is provided with a locking section having grooves thereon. The locking grooves may take the form of one or more annular grooves, as shown, for example, in U.S. Pat. No. 3,230,818 to G. Siebol. It has been found, however, that a thread-like spiral locking groove is preferable to annular grooves. Although a locking section having a spiral locking groove may not provide as high an installed mandrel retention load (the force required to pull an installed mandrel out of its sleeve) as one having annular grooves, the installed mandrel retention load will be uniform along the length of the spiral locking groove. On the other hand, in a locking section having annular grooves, the installed mandrel retention load depends on where the locking section is located when the sleeve is deformed to effect mandrel retention. Obviously, the material will not flow into the ridges between locking grooves. The annular ridges can, therefore, provide an area in which there is little if any resistance to withdrawal of the mandrel. In a locking section with a spiral locking groove, those areas of minimal resistance are distributed lengthwise along the locking section.
Spiral locking grooves offer an additional advantage over annular grooves. The edges of a spiral locking groove are significantly less likely to abrade the sleeve bore than the edges of an annular locking groove. Annular locking grooves may tend to break small chips of material off the inside of the sleeve during installation of the fastener. These chips may accumulate in the fastener installation device and, eventually, clog the device. The material buildup, tool damage and resulting downtime can be quite expensive.
It is conventional in the art to provide the stem with a weakened section, termed a "breakneck" groove. The mandrel stem is designed to fracture at the breakneck groove when the tension reaches a predetermined maximum load during installation, whereupon the gripping section of the stem separates from the remainder of the stem disposed within the sleeve. As is commonly known in the art, the breakneck groove is formed in a two-step rolling process. First, the groove is notched into the mandrel blank. This process creates bulges or ridges of material displaced on either side of the groove which present relatively sharp corners. If these ridges were not removed, they would scoop material from the sleeve bore during installation, creating chips of material that may clog the fastener installation device, as discussed above. Accordingly, the stem is rolled so that the area next to the breakneck groove is rolled down and the groove is rolled almost completely shut, thereby reducing any sharp corners that could catch the sleeve bore.
The prior art has long sought to improve the installed mandrel retention load of fasteners. These efforts have focused on ways to improve the flow of material from the sleeve into the grooves in the mandrel stem locking section. One approach has been to apply axial force to the fastener sleeve flange with a pulling head nosepiece having a sharp protruding configuration which acts to stake material from the sleeve into the locking grooves. An example of this approach is the Cherry T Rivet..RTM. Use of such an arrangement, however, may result in the production of tiny chips of material, which are broken from the sleeve during displacement of the sleeve material by the pulling head nosepiece. As discussed above, these tiny chips are quite detrimental. In addition, such sharp protruding nosepieces are relatively expensive, and their use renders the fastener installation process sensitive to wear or damage to the nosepiece. An incorrect, worn or broken sharp protruding nosepiece will preclude obtaining the proper interference fit between the sleeve and mandrel during installation of the fastener. The sharp protruding nosepiece tends to wear and break much more quickly than a planar nosepiece, which causes problems both due to inadequate fastener installation, increased cost of nosepiece replacement, and increased downtime. Because the operators of such equipment may be relatively unskilled, the worn or broken nosepiece may go unnoticed. Thus, a large number of fasteners may be improperly installed before the defective nosepiece is discovered. This can lead to weak joints or complete "pop-out" of the mandrels, in either case resulting in expensive repair of the workpiece with concomitant downtime.
The traditional problems with specially configured fastener installation tool nosepieces have been exacerbated by the recent application of powered fastener installation devices to automated assembly. These robot-mounted devices require a sturdy and simple design of the nosepiece so as to reduce the potential for error and downtime. The high installation volume and inability of the automated power fastener installation device to detect defects in the nosepiece render this problem critical.
The problems associated with the sharp protruding nosepiece have been reduced by use of a special fastener sleeve configuration, as disclosed in my co-pending patent application, Ser. No. 217,318, entitled "Fastener With Integral Locking Means," the disclosure of which is hereby incorporated by reference. Nevertheless, the need remains to improve the installed mandrel retention load of such fasteners. Accordingly, there exists a need for enhancing the interference between an installed fastener sleeve and mandrel having a spiral lock groove.


The core panel includes a plurality of carbon foam blocks. One or more of the blocks have a cell volume wherein at least about 90% of the cells have a diameter of between at least about 10 microns and about 150 microns. Also at least about 1% of the cell volume of the block has cells having a diameter of about 0.8 microns to about 3.5 microns.

1. Technical Field
The present invention relates to a laminated high strength monolithic carbon foam material that is especially useful for the production of decking for naval vessels and the like. More particularly, the present invention relates to reinforced carbon foam sandwiched between two composite facesheets, and exhibiting improved strength, weight and density characteristics desired for decking applications. The invention also includes methods for the production of such sandwiches.
2. Background Art
Decking for naval vessels and the like presents unique challenges. While metals such as steel and aluminum have traditionally been used where high strength is desired, the weight of these materials is such that the configuration of the vessels has to be specifically designed with the weight of the decking material in mind. In addition, metallic decking transmits heat and vibration, requiring specialized dampeners and other materials to be employed, at significant cost, and added weight. While composite laminates of for example, foams and wood products, have been suggested for decking applications, a composite having the required strength to weight ratio has not yet been found feasible. Added to this is the fact that laminate sandwiches developed to date are prone to failure through shear stresses—the tendency of the layers to fail laterally along the major surfaces of the sandwich.
Carbon foams have attracted considerable recent activity because of their properties of low density, coupled with either very high or low thermal conductivity. Conventionally, Carbon foams are prepared by two general routes. Highly graphitizable foams have been produced by thermal treatment of mesophase pitches under high pressure. These foams tend to have high thermal and electrical conductivities. For example, in Klett, U.S. Pat. No. 6,033,506, mesophase pitch is heated while subjected to a pressure of 1000 psi to produce an open-cell foam containing interconnected pores with a size range of 90-200 microns. According to Klett, after heat treatment to 2800° C., the solid portion of the foam develops into a highly crystalline graphitic structure with an interlayer spacing of 0.366 nm. The foam is asserted to have compressive strengths greater than previous foams (3.4 MPa or 500 psi for a density of 0.53 g/cc).
In Hardcastle et al. (U.S. Pat. No. 6,776,936) carbon foams with densities ranging from 0.678-1.5 g/cc are produced by heating pitch in a mold at pressures up to 800 psi. The foam is alleged to be highly graphitizable and provide high thermal conductivity (250 W/m·K).
According to H. J. Anderson et al. in Proceedings of the 43rd International SAMPE Meeting, p 756 (1998), carbon foam is produced from mesophase pitch followed by oxidative thermosetting and carbonization to 900° C. The foam has an open cell structure of interconnected pores with varying shapes and with pore diameters ranging from 39 to greater than 480 microns.
Rogers et al., in Proceedings of the 45th SAMPE Conference, pg 293 (2000), describe the preparation of carbon foams from coal-based precursors by heat treatment under high pressure to give materials with densities of 0.35-0.45 g/cc with compressive strengths of 2000-3000 psi (thus a strength/density ratio of about 6000 psi/g/cc). These foams have an open-celled structure of interconnected pores with pore sizes ranging up to 1000 microns. Unlike the mesophase pitch foams described above, they are not highly graphitizable. In a recent publication, the properties of this type of foam were described (High Performance Composites September 2004, pg. 25). The foam has a compressive strength of 800 psi at a density of 0.27 g/cc or a strength to density ratio of 3000 psi/g/cc.
Stiller et al. (U.S. Pat. No. 5,888,469) describes production of carbon foam by pressure heat treatment of a hydrotreated coal extract. These materials are claimed to have high compressive strengths of 600 psi for densities of 0.2-0.4 g/cc (strength/density ratio of from 1500-3000 psi/g/cc). It is suggested that these foams are stronger than those having a glassy carbon or vitreous nature which are not graphitizable.
Carbon foams can also be produced by direct carbonization of polymers or polymer precursor blends. Mitchell, in U.S. Pat. No. 3,302,999, discusses preparing carbon foams by heating a polyurethane polymer foam at 200-255° C. in air followed by carbonization in an inert atmosphere at 900° C. These foams have densities of 0.085-0.387 g/cc and compressive strengths of 130 to 2040 psi (ratio of strength/density of 1529-5271 psi/g/cc).
In U.S. Pat. No. 5,945,084, Droege described the preparation of open-celled carbon foams by heat treating organic gels derived from hydroxylated benzenes and aldehydes (phenolic resin precursors). The foams have densities of 0.3-0.9 g/cc and are composed of small mesopores with a size range of 2 to 50 nm.
Mercuri et al. (Proceedings of the 9th Carbon Conference, pg. 206 (1969) prepared carbon foams by pyrolysis of phenolic resins. For foams with a density range of 0.1-0.4 g/cc, the compressive strength to density ratios were from 2380-6611 psi/g/cc. The pores were ellipsoidal in shape with pore diameters of 25-75 microns) for a carbon foam with a density of 0.25 g/cc.
Stankiewicz (U.S. Pat. No. 6,103,149) prepares carbon foams with a controlled aspect ratio of 0.6-1.2. The patentee points out that users often require a completely isotropic foam for superior properties with an aspect ratio of 1.0 being ideal. An open-celled carbon foam is produced by impregnation of a polyurethane foam with a carbonizing resin followed by thermal curing and carbonization. The pore aspect ratio of the original polyurethane foam is thus changed from 1.3-1.4 to 0.6-1.2.
Unfortunately, carbon foams produced by the prior art processes are not effective for many high strength applications, such as naval decking, where high strength must be balanced with the need for light weight. In other words, decking, especially for an application such as a naval vessel, needs to be strong enough to withstand the weight to be applied to the decking, whether it is due to people aboard ship or equipment installed on the decking. At the same time, the decking must be lighter weight than steel or aluminum, the materials being replaced in such applications, in order to be considered worthwhile.
In U.S. Pat. No. 6,291,049, a foam core laminate is disclosed, having a core with opposing top and bottom surfaces; a plurality of discrete pins disposed through the core and extending beyond the top and bottom surfaces of the core; a face sheet on the top core surface; and a face sheet on the bottom core surface, the ends of each pin bent over and lying between the respective core surfaces and the facesheets. However, although useful for many applications, the resulting sandwich does not have the strength and weight characteristics needed for naval decking.


A bicycle frame attachable kneeling pad is described. The bicycle frame attachable kneeling pad is adaptable to a standard bicycle to provide new coaster usage where a user can propel forward with an active push leg, like a scooter, while resting a passive or compromised leg in the kneeling pad. The bicycle frame attachable kneeling pad includes a kneeling pad for supporting a user's passive or compromised leg while coasting on the bicycle, and a frame assembly for facilitating the assembly of the kneeling pad to the bicycle frame. The frame assembly may further include one or more crank arms that are attachable to a bottom bracket of the bicycle. The crank arms may then assemble with the frame member to ultimately attach the kneeling pad to the bicycle frame to provide the new coaster usage.

Various types of bicycles are known in the prior art. Generally, to operate a traditional bicycle a user needs two functioning legs to operate the pedals to crank the wheels. However, if one of the user's legs becomes compromised, due to injury for example, then the user is unable to operate their bicycle. In other scenarios, a user may desire a different bike riding experience that requires the use of only one leg for locomotion. In which case, the user must purchase a different type of bicycle or other locomotion device altogether. Thus, there is a need for a bicycle frame attachable kneeling pad that includes a kneeling pad disposed upon a frame assembly for coupling to a bicycle frame, said frame assembly disposed on one side of the bicycle frame and between a directable front wheel and at least one rear wheel, wherein a user is enabled to kneel upon the kneeling pad with one leg and probel the bicycle at a desired velocity by use of the other leg in striding contact with a ground surface.


Provided is an apparatus and method for allocating time slots to nodes without contention in a wireless network. The method for allotting time slots includes: receiveing a packet length and maximum allowable latencies of the nodes and converting them into data in symbol units; determining a beacon order so that a beacon interval representing a length of a superframe is smaller than or equal to a minimum value of the converted maximum allowable latencies; determining a superframe order so that the sum of a length of a beacon frame, a length of a contention access period, and a length of contention free period is smaller than a length of an active portion, based on the converted packet length; and allocating a guaranteed time slot without contention to each node according to an allocation priority order for the nodes.

A wireless sensor network (WSN) is one of essential techniques in the ubiquitous era and is greatly highlighted along with the rapid development of wireless communication and network theories. The wireless sensor network may be utilized for industrial vehicles, home automation, militaries, agriculture, health care, and other various fields. The design of the wireless sensor network system has a very close relation with a specific application program field. In the case of an industrial application, the wireless sensor network should have features such as real-time transmission, low energy consumption, high security, scalability and tenacity.
As specifications for physical layers and link layers of such a sensor network, IEEE 802.15.4 (Low-Rate Wireless Personal Area Network) is settled, and various application products of ZigBee using the same have been put into the market in various fields. In addition, IEEE 802.15.4 suggests wireless connection where a physical (PHY) layer and a medium access control (MAC) layer are defined.
After IEEE 802.15.4 is open to the public, many researchers have suggested a lot of improvements, which result in the improvement of performance of the corresponding specifications. For example, a performance analysis for the GTS allocation mechanism has been already introduced, and a traffic scheduling method for improving the energy efficiency of a network has been proposed. In addition, the implied GTS allocation mechanism has also been proposed for improving the utilization of GTS bandwidth, and the message scheduling method has been introduced for scalability and improvement of the real-time performance of industrial applications. In addition, the adaptive GTS allocation method has been proposed for improving the delay and fairness. However, despite such endeavors, IEEE 802.15.4 still has drawbacks in traffic scheduling due to inherent limitations of the specification.

Apparatus and method for allocating time slots to nodes without contention in wireless network