A cancellation circuit provides active electromagnetic shielding for canceling inductive noise in electrical circuits caused by electromagnetic flux. The cancellation circuit includes amplitude-adjustment and phase-adjustment circuits for adjusting the amplitude and phase of electrical signals, and a combining circuit for combining electrical signals such that the effects of electromagnetic induction cancel. An electromagnetic pickup is provided with a cancellation circuit for canceling its response to electromagnetic flux. An electromagnetic drive coil is provided with a cancellation circuit for canceling electromagnetic flux in a predetermined region of space, and a compensation circuit compensates for frequency-dependent phase and amplitude variations in electrical pickup signals and transmitted electromagnetic flux. The cancellation and compensation circuits may be combined to provide a device that can simultaneously transmit and receive electromagnetic radiation.

The present invention relates to electromagnetic shielding for shielding electromagnetic pickups, other types of electronic equipment, and specific regions of space from electromagnetic radiation, and more particularly to active electromagnetic shielding for providing an electrical cancellation signal for canceling electromagnetic radiation or canceling the response of an electronic device to electromagnetic radiation.
It has long been known that voltages are induced in all conductors exposed to changing magnetic fields regardless of the configuration of such conductors. Electromagnetic radiation will induce electrical signals in electronic devices according to the laws of magnetic induction. Thus it has been desirable in some applications of electronic instrumentation to reduce the inductive noise caused by electromagnetic radiation.
A common method for providing electromagnetic shielding involves the use of passive electromagnetic shielding. A shield consisting of layers of high and low permeability material may be used to attenuate electromagnetic radiation passing through it. However, this passive electromagnetic shielding adds substantial bulk and weight to the system which it shields.
Another method for providing electromagnetic shielding is to utilize cancellation coils for generating a cancellation electromagnetic radiation in opposition to incident radiation produced by external sources in order to cancel the effects of the incident radiation. In U.S. Pat. No. 5,066,891, Harrold presents a magnetic field sensing and canceling circuit for use with a cathode ray tube (CRT). Magnetic flux gate sensors provide output signals that are functions of detected fields. These signals are then used to control the current in the cancellation coils which produce a cancellation magnetic field. Harold explains that it is of great importance that the CRT in a color monitor be protected from the effects of external magnetic fields, and, in particular, time-varying magnetic fields. However, this method provides no compensation to the frequency-dependent amplitude and phase responses of the sensor that picks up incident electromagnetic radiation and the device which generates the cancellation radiation.
Likewise, in U.S. Pat. No. 5,132,618, Sugimoto shows a magnetic resonance imaging system that includes active shield gradient coils for magnetically canceling leakage fields that would otherwise produce eddy currents in the heat shield tube.
A common method for providing shielding to an electromagnetic pickup is to utilize identical pickup coils connected in series or in parallel so as to cancel the effects of uniform electromagnetic radiation. Pizzarello shows such a system in U.S. Pat. No. 5,045,784 for reducing inductive noise in a tachometer coil. An electric tachometer is a coil of wire that may be attached to a moving part of a motor that passes through a stationary magnetic field. The motion of the wire through the magnetic field induces a voltage that is indicative of the motor's speed. However, if the motor is powered by electricity, changes in the current powering the motor will cause a magnetic flux, which will also produce a voltage in the coil. Pizzarello shows a stationary pickup coil that is responsive to magnetic flux, and a means for subtracting the pickup voltage from the tachometer voltage.
Likewise, in U.S. Pat. No. 4,901,015, Pospischil shows a cancellation circuit for canceling the response of a magnetic pickup generators to ambient electromagnetic fields. Pickups used in integrated drive generators are responsive to ambient electromagnetic fields produced by the generator. A first magnetic pickup responsive to the ambient magnetic field and a modulated flux field produced by a rotating shaft is combined with a second magnetic pickup responsive to the ambient electromagnetic fields in order to cancel the inductive effects of the ambient electromagnetic field. Such pickup assemblies are also used with electric guitars and are known as "hum-bucking" pickups. This technique is not effective for providing a high degree of cancellation because slight differences between the pickups, even pickups that are substantially identical, cause the frequency-dependent amplitude and phase response of the pickups to differ significantly from each other. Thus the pickup signals will not be exactly out of phase and equal in amplitude when they are combined.
A prior-art method for providing shielding to an electromagnetic pickup from an electromagnetic source that produces a non-uniform field is to "unbalance" either the pickup device or the electromagnetic source. Such a method is described by Hoover in U.S. Pat. No. 4,941,388. Hoover uses amplitude-adjustment techniques to compensate for amplitude variations between the responses of separate pickups to electromagnetic radiation generated by an electromagnetic sustaining device for driving the vibrations of a string on an electric guitar. However, Hoover does not compensate for differences in the pickup coils which cause the amplitude-variation of the responses of the pickups to be frequency-dependent, thus resulting in poor cancellation over a broad range of frequency. Furthermore, Hoover does not compensate for phase-variations that occur between different pickup coils. The resulting cancellation from the unbalancing method is poor.
Hoover describes the operation of negative feedback in a system where a magnetic pickup provides an electrical signal to a magnetic driver which generates a magnetic field to which the pickup responds. Hoover mentions that the system tends to drift from the negative feedback condition at higher frequencies, and identifies the cause of this drift as distortions in the phase-response of the system resulting from the pickup, driver and amplifier in the system. Hoover neither presents an effective method for controlling the phase-response of the system, nor shows the mathematical relationships between phase and frequency resulting from the driver and pickup coils. Rather, Hoover proposes the use of a low-pass filter to reduce the gain of the system at which the negative feedback condition breaks down.
Methods of active phase-compensation are described by Rose in U.S. Pat. Nos. 4,907,483, 5,123,324, and 5,233,123. Rose uses active circuits for determining the frequency or frequency range of an electrical signal from an electromagnetic pickup. Active phase-adjustment is applied to the pickup signal, which is used to power an electromagnetic driver that generates an electromagnetic driving force on a vibratory ferromagnetic element of a musical instrument. The purpose of the phase-adjustment of the pickup signal is to provide a driving force to the vibratory element that is substantially in-phase with its natural motion. Because the purpose of Rose's invention is to improve the efficiency of the electromagnetic drive force on the element, it is apparent that a passive phase-compensation circuit would be preferable to Rose's active phase-compensation circuit. However, Rose does not realize the mathematical relationships between phase and frequency which provide the basis for constructing a passive phase-compensation network. Furthermore, Rose's invention does not provide simultaneous phase-compensation to more than one harmonic.
Another method for providing electromagnetic shielding is to orient the angle of a pickup coil to incident electromagnetic radiation such that the electrical current induced in the coil by the electromagnetic radiation will substantially cancel. One application of this method is shown by Burke in the Handbook of Magnetic Phenomena, published in 1986. Burke uses a transmitting coil that produces electromagnetic radiation and a receive coil which senses radiation. The two coils can be configured in such a way that no energy is transferred between the transmitting and receiving coils. Burke shows the receiving coil oriented with the axis of its turns at right angles to the direction of the magnetic field produced by the transmitting coil. Burke explains that the instantaneous generated voltage of the receive coil is determined by the instantaneous rate of change of the magnetic flux passing through the coil. If the flux is directed at right angles to the coil's axis, none of it is intercepted by the coil, and the instantaneous rate of change through the coil is zero. This method of cancellation was used in an electromagnetic sustain device for electric guitars marketed by T Tauri Research of Wilmette Ill. in November, 1988, and patented by Tumura, European Patent Application No. 92307423.1 filed on Aug. 13, 1992, and U.S. Pat. No. 5,292,999. The actual effectiveness of this technique is limited by several factors, such as the uniformity of the pickup coil's windings, the uniformity of the electromagnetic radiation near the pickup, interference due to other nearby conducting materials, and the difficulty of precisely positioning a pickup coil in a field whose intensity varies as the inverse square of the distance from its source.
Another method for providing active electromagnetic shielding is the differential transformer also shown by Burke. The differential transformer comprises a drive coil for generating a magnetic flux, and two pickup coils wrapped around a ferromagnetic core that includes a moveable armature that, when moved, varies the reluctance of the magnetic path associated with each pickup coil. If the two pickup coils are identical, and if the two magnetic paths about which they are wound are identical, the voltages induced in each pickup coil will be the same. However, Burke explains that the two pickup coils nor the two magnetic paths can be made exactly the same, therefore a differential transformer will always have some output voltage under zero stimulus.
Coils of wire whose currents support magnetic fields in space function as antennas radiating electromagnetic energy. There are several cancellation methods used with antennas that act as electromagnetic shielding. One of these methods is the basis of operation for a sidelobe canceller which uses an auxiliary antenna in addition to a main antenna. Combining the outputs from the two antennas results in cancellation of the antenna beam pattern in the direction of a noise source so that the effective gain of the antenna in that direction is very small. Likewise, the multiple sidelobe canceller addresses the problem of multiple noise sources.
Delay line cancellers are used in systems where multiple radar pulses are transmitted, and are used to detect moving objects. In a single-element delay line canceller, a received pulse is delayed and added to another pulse received later so that the pulses reflected by stationary objects are out of phase and thus cancel, whereas the pulses reflected by moving objects do not cancel.
Several methods are used to allow an antenna to simultaneously transmit and receive electromagnetic radiation. For example, in a continuous wavelength radar system, a single antenna may be employed since the necessary isolation between transmitted and received signals is achieved via separation in frequency as a result of the Doppler effect. The received signal enters the radar via the antenna and is heterodyned in a mixer with a portion of the transmitted signal to produce a Doppler beat frequency.
An intermediate-frequency receiver may use separate antennas for transmission and reception. A portion of the transmitted signal is mixed with an intermediate frequency, then a narrow-band filter selects one of the sidebands as the reference signal which is mixed with the signal from the receiver antenna.
It is one object of the present invention to provide active electromagnetic shielding for canceling the effects of electromagnetic induction in electrical circuits. It is a related object of the present invention to reduce interference between transmitters and receivers of electromagnetic radiation that operate simultaneously. It is another object of the present invention to provide a cancellation circuit that allows a single antenna element to simultaneously transmit and receive electromagnetic radiation. It is still another object of the present invention to compensate for frequency-dependent amplitude and phase responses of electromagnetic receivers and transmitters.

Inductive noise cancellation circuit for electromagnetic pickups


A method of analysis of a time interval between two selected measurement edges of interest includes locking a plurality of at least three substantially interchangeable oscillators to a common reference frequency, the oscillators containing digital locked-loop (DLL) circuit architecture. The method includes operating one oscillator as a timebase oscillator, and operating the other oscillators as edge-resettable measurement oscillators. The method further includes coupling one oscillator with a switched and physically-immutable parametric variation, producing an offset in the frequency of the coupled oscillator relative to the frequency of the other oscillators. The method includes phase-aligning each of the measurement oscillators to a triggering pulse created by one of selected measurement edges of interest, oscillating each phase-aligned measurement oscillator until its phase matches the phase of the timebase oscillator, and counting the number of oscillation cycles of the phase-aligned measurement oscillator from the time of phase-alignment until the time of phase matching.

U.S. Pat. No. 4,164,648 (hereinafter referred to as "HP TIA," where "TIA" is an abbreviation for "time interval analyzer") describes an approach to time interval measurement using three analog phase locked loops. Additionally, this patent identifies the shortcomings of a two-ring oscillator time vernier approach, described for example in U.S. Pat. No. 6,295,315 and PCT International Patent WO 01/69328 A2 (hereinafter referred to as "traditional"), currently used almost exclusively. In accordance with HP TIA, all loops are locked to a common reference frequency. Two of the loops differ slightly from a third loop, referred to as the "reference." Implementation is almost exclusively via analog circuitry.
Using analog PLL circuit techniques of HP TIA, three oscillators are locked to a system clock. One is a reference signal oscillator, and the remaining two are measurement oscillators. The measurement oscillators are locked to a frequency that differs from the reference signal by 1+1/N or 1−1/N, where N is an integer. Given an arbitrary phase and frequency start of a measurement oscillator, the phase of the measurement signal gains (or loses) until it matches the phase of the reference signal. Phase alignment requires a number of reference signal clock cycles, wherein the number of cycles is determined by the value of N.
The traditional circuit approach uses only two free running ring oscillators, whose slightly differing frequencies are calibrated at the start of the circuit operation, usually just after reset. The phase measurement is made using a measurement edge to start each oscillator and, like the HP TIA circuit above, counts how many clock cycles elapse for the phases to align. The free running oscillators, even if initially calibrated accurately, are unlikely to retain calibration at the time of measurement, if measurement occurs significantly later. The traditional circuits leave the oscillators off before a measurement, such that the precise dynamic bias conditions that existed during calibration will not apply during the measurement, if the oscillators are off for any significant period of time. If the oscillators are left on, the elapsed time between calibration and measurement may allow for a drift in the frequencies in either or both of the oscillators.


A piston (10) particularly suited for heavy duty diesel engine applications includes upper and lower crown sections (28, 30) joined by a friction weld (32) to define an annular ring belt (14) formed with ring groves (22) and having a lower end (20) and an internal piston cooling chamber (34). A pair of pin bosses (40) depend from the ring belt (14) and are formed as one piece with the lower crown section (30). A skirt (46) is also formed as one piece with the pin bosses (40) and has an upper end (48) that is spaced from the lower end (20) of the ring belt (14) to define a space (52) therebetween which effectively uncouples the skirt (46) from the ring belt (14).

1. Technical Field
This invention relates generally to pistons for heavy-duty engine applications.
2. Related Prior Art
Pistons for heavy-duty applications include an upper head formed with a ring belt having pin bosses depending therefrom for connecting the piston to a connecting rod of the engine. Such pistons also include a piston skirt that is formed either as one piece with the head and pin boss portions, or formed as a separate structure which is coupled in articulated fashion to the pin bosses via the wrist pin.
In pistons having a unitized skirt, axial loading from the combustion gases is transmitted through the head to the pin boss section. Since the skirt is coupled directly to the head as an extension of the ring belt, the skirt also sees axial loads. Such unitized skirts also tend to be overly rigid, as they are tied directly to the ring belt as one piece. Such inflexible skirts may make sensitive to scuffing or marking of the skirt and cylinder wall during radial thrust loading of the skirt. U.S. Pat. No. 6,155,157 shows such a piston.
Still a further characteristic of forming the skirt as one piece with the ring belt is that the heat from the head is transmitted directly to the skirt, and thus added clearance must be provided between the skirt and cylinder wall to compensate for thermal expansion of the skirt, sacrificing closeness of fit between the piston skirt and cylinder wall.
A piston constructed according to the present invention overcomes or minimizes the above difficulties associated with monobloc pistons.
A piston constructed according to the invention for heavy duty engine applications comprises a piston head having a peripheral ring belt with a lower end and a pair of pin bosses depending from the head portion, each formed with a wrist pin hole. An internal piston cooling gallery is formed in the head and includes a bottom wall coupled to and extending radially inwardly from the ring belt. The piston construction includes a piston skirt coupled directly and immovably to the pin bosses having an upper free end which is spaced in uncoupled relation from the lower end of the ring belt and the bottom wall of the piston cooling gallery.
A method is provided for making such a piston and comprises forming a head portion of the piston having an internal cooling gallery, a peripheral ring belt with a lower end and a pair of depending pin bosses, and unitizing a piston skirt with the pin bosses in direct immovable relation thereto, and having an upper free end of the skirt arranged in spaced uncoupled relation to the lower end of the ring belt.
One advantage offered by such a piston construction is increased flexibility of the skirt, since it is no longer united directly to the ring belt, and thus is free to flex and give under radial loads, thereby decreasing the occurrence of scuffing or marking of the cylinder walls associated with the aforementioned rigid skirts.
Another recognized advantage of uncoupling the skirt from the ring belt is that the intervening space precludes the axial loads imparted to the head by combustion gases from being transmitted to the skirt. Such loads are instead transmitted directly to the pin bosses, isolating the skirt from such axial loads.
Another advantage of the uncoupled skirt configuration is that the intervening space serves as an insulation barrier to prevent direct transmission of heat from the head to the skirt. By isolating the skirt from the heat of the head portion, the skirt is subject to far less thermal expansion and thus can be designed with a closer fit relative to the cylinder wall than the traditional coupled skirts above.
Still another advantage recognized by the subject piston construction is that it requires relatively less material to manufacture and is thus lighter in weight and less costly to produce than traditional monobloc pistons.


A molded fluidic device having a power nozzle with a width W and a coupling passage coupling a source of fluid to said power nozzle. The coupling passage has a planar enlargement and a plurality of posts spaced across the enlargement, the spacing S between each post being less than the width of the power nozzle with the sum of spacing S being greater than the width W.

Fluidic oscillators as shown in FIG. 1 are well known and particularly useful in liquid spray applications such as washer nozzles. Such fluidic oscillators are typically manufactured of molded plastic and comprise a fluidic oscillator circuit OC or silhouette molded in a chip or insert 13 and a housing 10 having a cavity 11 into which the chip or insert 13 is forcibly inserted. A source of fluid under pressure is supplied to the power nozzle PN in the fluidic oscillator circuit OC by way of an inlet pipe or barb 12. Care is taken in the design to assure a seal between the housing internal surfaces and the mating surfaces of the chip or insert. In mass manufacturing of such chips and housing, small loose plastic particles can be carried by liquid flow and can clog portions of the fluidic circuit or outlet thereby blocking the flow of liquid (washer liquid in the case of a washer nozzle). In the case of fluidic oscillators, this interrupts the oscillation function.
There have been efforts to place screens or discrete filter screens upstream of the fluidic circuit, but these expedients add cost and complexity to the device. Thus, the problem solved and addressed by the present invention is potential clogging of liquid flow devices. The invention solves this problem by integrally providing extra places or enlargements and spaced posts for contaminants or loose particles to lodge or become trapped in areas other than main flow areas so that there are additional flow passages or ways for liquid to flow if a contaminant or particle blocks one or more passages or spaces between posts.
The invention provides for low profiles in areas specifically designed to encourage contaminants to flow into and stop in areas other than the power nozzle or the main jet flow area. By providing integral molded enlargements with spaced posts in areas as described above, the fluidic nozzle can continue to function in spite of partial upstream blockage in the enlargement area because a power jet channel is still completely open. In the absence of the present invention, contaminants usually flow directly into the power nozzle or the main jet area, thereby making the system nonfunctional.
The invention features a molded fluidic device having a power nozzle with a width W and a coupling passage coupling a source of fluid to said power nozzle. The coupling passage has an enlargement and a plurality of posts spaced across the enlargement, the spacing S between each post being less than the width of the power nozzle with the sum of spacings S being greater than the width W and the coupling passage and posts being integrally molded with the fluidic device. The dimensions of the coupling passage, the planar enlargement and the spacing S are such that the fluidic flow rate from the source to the power nozzle is substantially unaffected when a foreign particle blocks any one of the spaces between the posts. In a preferred embodiment, fluidic is a liquid oscillator which issues a fan spray of liquid droplets to ambient and wherein the dimensions of the planar enlargement and the spaces S are such that the fan spray is substantially unaffected when one or more foreign particles is trapped in any one or more of the spaces. The coupling passage and the posts are molded as an integral molding with the fluid device. A housing member into which the integral molding is inserted has a coupling to a source of liquid under pressure.
The invention has advantageous usage in molded liquid-spray nozzles, particularly when the liquid is sprayed to ambient; and still more particularly when the liquid is a wash liquid to be sprayed on a surface to be washed, such as vehicle glass.
Benefits of the present invention include the following:
1. Provides for prolonged life for the system in which the nozzle is used. PA1 2. Provides a filter mechanism free of cost compared to in-line filters which require a separate component and some of which require a hose to be cut to include the filter, install the filter, etc.

Nozzles with integrated or built-in filters and method


A wall construction for a combustion chamber or thrust nozzle of a high power engine of a flying body includes an inner wall body that is subjected to the hot gases within the combustion chamber, and an outer jacket that surrounds the inner wall body and carries the mechanical loads. The inner wall body has a plurality of cooling channels through which a cooling medium may flow. The outer jacket is made of a long-fiber C/SiC composite material, while the inner wall member is made of a short fiber C/SiC composite material. The reduced thermal expansion coefficient of this ceramic composite material in comparison to metal alloys leads to a reduced straining and reduced deformation of the wall construction and therewith an increased operating life.

German Patent Publication 3,535,779 discloses a thrust nozzle for a high power engine, for example for a booster rocket or a reusable spacecraft, which has a rotationally symmetric contour. The circular cross-section of the known thrust nozzle tapers or becomes narrower starting from the combustion chamber in a direction toward the constricted throat of the nozzle, whereafter it again expands or becomes wider outwardly. Such a known rotationally symmetric contour is simple to manufacture using known production technology and makes it possible to effectively withstand the arising gas pressure forces.
Due to the high operating temperatures of approximately 3000.degree. C., it is in any event necessary that the thrust nozzle must be effectively cooled. In the conventional thrust nozzle, which comprises an inner casing or jacket made of a copper alloy, the necessary cooling is achieved by providing cooling channels extending in the circumferential direction or in the axial direction in the inner jacket. A cooling medium, such as the liquid hydrogen that is to be combusted in the combustion chamber or thrust nozzle, flows through the provided cooling channels and thereby cools the thrust nozzle. The conventional thrust nozzle further includes an outer support casing or jacket that externally surrounds the inner jacket in a joint-free manner, whereby this outer support jacket serves to take up and withstand the forces arising from the combustion gas pressure. For this purpose, the support jacket must comprise a high tensile strength, while its thermal resistance or temperature stability is of lesser importance due to the cooling that is provided.
Efforts are currently being pursued for developing hypersonic aircraft, which will similarly utilize such thrust nozzles. Due to weight, fuel capacity, and cost considerations, these thrust nozzles must achieve a high efficiency of thrust generation, whereby several engines are typically to be arranged clustered adjacent one another. In order to meet these requirements, there have already been proposals of thrust nozzles of which the cross-sectional contour transitions from a round cross-section in the area of the combustion chamber to a quadrilateral cross-section in the area of the exhaust outlet of the thrust nozzle or even in the area of the constricted throat of the thrust nozzle. Such a configuration in turn requires that the thrust nozzle wall has a complex curved contour.
On the one hand, the relatively soft inner jacket must have an inner contour exactly matching a prescribed shape in order to achieve an optimal combustion and gas through-flow. On the other hand, the outer supporting jacket must be sufficiently rigid and configurationally stiff for strength reasons. Therefore it becomes impossible to achieve a matching or adaptation of the outer jacket to the form of the inner jacket. As a result, it becomes necessary to manufacture the two jackets with a very high degree of matching shape accuracy, which necessitates the use of very complicated and costly production processes in view of the complicated geometry that is involved. A further disadvantage is that it is possible for hollow spaces or gaps to remain between the two jackets after they are joined together, whereupon these hollow spaces or gaps can lead to deformations, cracking and ultimately failure of the inner jacket during operation of the combustion chamber and thrust nozzle. As a result, the operating life of the rocket engine is limited.
To overcome the above discussed disadvantages, German Patent Publication 4,015,204 discloses a thrust nozzle for an aeronautic or aerospace engine comprising an inner casing or jacket that has a high thermal conductivity and that is provided with a plurality of cooling channels, a rigid and strong support casing or jacket externally surrounding the inner jacket, and an intermediate layer that is integrally cast in place between the inner jacket and the outer support jacket. In this manner, the intermediate layer serves to compensate for any production tolerance between the inner jacket and the outer support jacket so that the requirements of shape accuracy of the two jackets can be reduced.
German Patent Publication 4,115,403 discloses a thrust nozzle wall construction for expansion ramps and hot gas nozzles that comprises an outer supporting structure arranged facing away from the hot gas, as well as a multi-layered inner structure having a plurality of mutually spaced-apart cooling channels that run along the inner structure facing toward the hot gas that is present inside the nozzle. In order to achieve a high thrust output, and in order to simplify the exchangeability of the nozzles between different types of engines, thrust nozzles having a quadrilateral configuration are particularly suitable. However, the nozzle walls of such thrust nozzles are subjected to high pressure forces and high temperatures. In contrast to the walls of circular cross-section nozzles, flat planar nozzle walls of quadrilateral nozzles or combustion chambers are subjected to high bending moments due to the pressure forces of the combustion gases. As a result, bulging or bending deformations and overstrain conditions can arise in the thrust nozzle walls, which jeopardize the proper functioning of the thrust nozzle according to specifications. An additional difficulty arises in view of the so-called bi-metal effect, due to the different metal components of the inner jacket and of the outer jacket and due to the temperature differences through the multi-layered wall. In order to avoid thrust losses and leakage flows, it is therefore necessary to provide very rigid, form-stable, cooled walls for the combustion chamber and the thrust nozzle.
For the above reason, this known thrust nozzle wall comprises an inner structure that consists of an inner thermal conduction layer that is impinged upon by the hot gas, as well as a heat resistant gliding layer. The required cooling channels are embedded in the thermal conduction layer, and these are elastically connected to the supporting structure by means of a plurality of holding elements that penetrate through the gliding layer. In this context, the gliding layer can consist of a ceramic granulate, while the thermal conduction layer consists of copper. The holding elements can be embodied in the form of small pipes or tubes. However, due to the required minimum strength in this context, an adequate straining distance is not available when the thrust nozzle is subjected to the extremely high thermal loading that is typical in the operation of high power engines. Due to the high thermally induced tensions, which cause considerable plastic strain deformation of these holding elements particularly, the operating life of the wall construction is drastically limited.
The above discussed limitation of the operating life is predominantly caused by a failure or defect formation, for example the formation of a crack in the combustion chamber wall, after a limited number of load cycles and associated plastic deformations and creeping of the components due to the thermally limited strains, in other words due to the secondary stresses caused by the high thermally induced stresses amounting to approximately 80% of the total load.
For the above reasons, not only is the reusability of the combustion chamber and thrust nozzle or overall engine system sharply limited, but also the total costs of the booster or other propulsion system are significantly increased. Moreover, thrust losses and overloading of the various engine components, including the known turbo-pumps for pumping the fuel, oxidizer, and/or coolant, also arise during operation of the engine, and, for example, lead to the formation of cracks or the like in these various components.
Even in the case if intermediate materials are arranged between the inner wall that is exposed to the hot gases and the outer supporting structure, such as sintered aluminum or foamed aluminum materials for example, which can take up and effectively absorb relatively high deformations, irreversible deformations in the plastic deformation range ultimately also arise, so that any such constructions are only suitable for single use engine concepts.
The above discussed support elements arranged between the inner hot gas wall and the outer surrounding structure, when made of conventionally known materials, are intended to achieve a defined yielding in the direction of their respective length as a result of associated widthwise or crosswise strain during operation of the high power engine. However, the known materials for making such supporting elements do not comprise an adequate elastic strain characteristic. As a result, the elastic strain required for the desired compensating effects during operation of the engine is not provided.
German Patent Publication 3,136,252 describes a ceramic combustion chamber wall for burner heads and combustion chambers, which are installed in combustion and drive plants or assemblies. In this context, the combustion chamber wall of the combustion space is an integrated component of a ceramic heat exchanger with single-stage or multi-stage flow channels. By means of strand pulling or extrusion techniques, film techniques, and winding or wrapping techniques, it is possible to produce such combustion chamber walls with parallel-flow, counter-flow, and/or cross-flow heat exchangers, as they are otherwise usually produced in metal embodiments. The use of silicon carbide or silicon nitride is suggested as the material for the combustion chamber wall.

Combustion chamber wall construction for high power engines and thrust nozzles


An evacuation hand piece for collecting debris during dental procedures. The hand piece is adapted for attachment to evacuation apparatus and provides both intra- and extra-oral suction. A body member of the hand piece has a contoured outer gripping surface which makes the hand piece easier to grasp. A mask is disposed at one end of the hand piece to create a suction area which is larger than the cross sectional area of the body member. The mask is attached to a spherical tip of the body member to form a ball and socket-type connection which permits directional adjustment of the mask, thereby maximizing the effective extra-oral suction of the hand piece. The mask is formed from transparent material to allow viewing through the mask during dental procedures.

Dental procedures, especially dental procedures using air abrasion systems, produce a number of particulate by-products which must be collected with evacuation apparatus. For example, when an air abrasion system is used to reduce a tooth, the process produces not only spent abrasive material but also portions of tooth, blood, gums, and other debris. This debris must be removed during the dental procedure to allow the dentist to monitor progress and to make the procedure more comfortable to the patient. During air abrasion procedures, it will be appreciated that while most of the abrasive material collects in the mouth of the patient, some abrasive material deflects out of the mouth and into the surrounding area. As a result, evacuation apparatus is needed which removes debris from both inside and outside the mouth.
Evacuation hand pieces are known which attempt to provide both intra- and extra-oral evacuation. These devices typically have a larger diameter cylindrical handle portion with a coaxially mounted smaller diameter tube. The tube is sized for insertion into the patient's mouth while the handle portion has holes extending through an end thereof and is generally positioned just outside of the mouth during dental procedures. These hand pieces are connected to evacuation means such as a vacuum pump to create a suction flow through the hand piece. Accordingly, suction flow is created through the tube and the holes located in the handle portion.
Unfortunately, conventional evacuation hand pieces do not adequately collect debris from both inside and outside the mouth. The area of suction created outside the mouth in such hand pieces is limited by the size of the handle portion. The handle portion must be small enough to be held and also must be small enough to allow the dentist to adequately see inside the mouth during the procedure. It will be appreciated, however, that the extra-oral suction area created by the hand piece is directly related to the size of the handle portion, and therefore a smaller diameter handle portion evacuates a smaller extra-oral area. Accordingly, conventional evacuation hand pieces are either too big and therefore cannot be easily held or used during dental procedures, or are too small and collect only a fraction of the debris which deflects from the mouth.
Conventional evacuation hand pieces further fail to maximize extra-oral suction from all areas of the mouth. During some procedures, the evacuation hand piece must be placed near the corner of the mouth and therefore a portion of the holes in the handle portion are disposed near the cheek of the patient rather than the mouth. Debris, however, deflects out of the mouth and therefore the holes disposed over the cheek are ineffective to collect debris. Accordingly, conventional evacuation hand pieces do not maximize the effectiveness of the extra-oral suction holes.
Furthermore, the extra-oral suction provided by conventional evacuation hand pieces is localized in that it does not address debris escaping from the other side of the mouth. During a dental procedure, the evacuation hand piece is typically placed on a first side of the mouth while the dentist works on a second side. As noted above, a handle with holes is typically provided in conventional hand pieces for creating extra-oral suction. The suction produced by such hand pieces, however, simply collects debris from the first side of the mouth. As a result, debris escapes through the second side of the mouth unimpeded by the conventional hand piece.
Furthermore, conventional evacuation hand pieces are overly cumbersome to sterilize between patients. During dental procedures, the evacuation hand piece is positioned so that the smaller tube extends into the patient's mouth while the handle is located near the patient's mouth. Conventional hand pieces have an integral tube and handle assembly and therefore both the tube and handle must be sterilized between each use.

Evacuation hand piece for use during dental procedures


A fixing solution having a pH.gtoreq.7 and comprising a fixing amount of sulfite and a fix accelerating amount of a thioether compound; wherein the fixing solution contains less than 0.05 moles/liter of thiosulfate and a method of processing an imagewise exposed and developed silver halide photographic element comprising fixing in said fixing solution a silver halide photographic element containing at least one emulsion or deposit of silver halide comprising greater than 90 mole % silver chloride.

The basic image-forming process of silver halide photography comprises the exposure of a silver halide photographic element to actinic radiation (for example, light or X-rays), and the manifestation of a usable image by the wet, chemical processing of the element. The fundamental steps of this processing entail, first, treatment of the photographic element with one or more developing agents wherein some of the silver halide is reduced to metallic silver. With black-and-white photographic materials, the metallic silver usually comprises the desired image. With color photographic materials, the useful image consists of one or more images in organic dyes produced from an oxidized developing agent formed where silver halide is reduced to metallic silver.
To obtain useful black-and-white images it is usually desirable to remove the undeveloped silver halide, and to obtain useful color images it is usually desirable to remove all of the silver from the photographic element after the image has been formed. In black-and-white photography the removal of undeveloped silver halide is accomplished by dissolving it with a silver halide solvent, commonly referred to as a fixing agent. In color photography the removal of silver is generally accomplished by oxidizing the metallic silver, and dissolving the oxidized metallic silver and undeveloped silver halide with a fixing agent. The oxidation of metallic silver is achieved with antioxidizing agent, commonly referred to as a bleaching agent. The dissolution of oxidized silver and undeveloped silver halide can be accomplished concurrently with the bleaching operation in a bleach-fix process using a bleach-fix solution, or subsequent to the bleaching operation by using a separate processing solution containing a fixing agent.
It is highly desirable to process a photographic element as rapidly as feasible, and a shortened process compared to ones known in the art is highly desired. Shortening the silver removal step, which consumes a large amount of the total process time, is one manner in which to shorten the overall processing time. Juxtaposed to the desire for an accelerated process is the desire for, and the need for, photographic elements and processing solutions that require lower chemical usage and that generate less polluting chemical waste.
A wide variety of fixing agents and silver solvents are known. Such materials form relatively stable and soluble reaction products with silver ion or silver halides. Such agents include, for example, alkali metal and ammonium thiosulfates, thiocyanate salts, sulfites, cyanides, ammonia and other amines, imides as described in U.S. Pat. No. 2,857,274; thiols as described in U.S. Pat. Nos. 3,772,020 and 3,959,362; mesoionic 1,2,4-triazolium-3-thiolates as described in U.S. Pat. No. 4,378,424 and other mesoionic heterocyclic thiolates as described in European Patent Application 431,568; thioureas, thioacids, and thioethers as described in German Offen. 2,037,684 and U.S. Pat. Nos. 2,748,000; 3,033,765; 3,615,507; 3,958,992; 4,126,459; 4,211,559; 4,211,562; 4,251,617; and 4,267,256; phosphines as described in U.S. Pat. No. 3,954,473; and concentrated halide solutions as described in U.S. Pat. No. 2,353,661.
Thiosulfate salts are generally preferred as fixing agents because they are inexpensive, highly water soluble, non-toxic, non-odorous, and stable over a wide pH range in the fixer bath. Furthermore, thiosulfate salts form very stable, water soluble reaction products with both silver ion and with silver halides. Sulfite salts are practical fixing agents for the same reasons as thiosulfate mentioned above, except sulfites are not useful for the fixing of silver bromide or silver iodide containing materials. Sulfite salts are effective fixing agents for high chloride elements, as indicated, for example, in U.S. Pat. No. 5,171,658. On a mole for mole basis, sulfites are not as rapid in fixing action as thiosulfates, but sulfites contribute less sulfur waste, less BOD (biochemical oxygen demand), and less COD (chemical oxygen demand) to photographic processing waste than do thiosulfates. Therefore, there is a need to improve the fixing speed of sulfite fixing agents for silver chloride photographic materials so that the environmental advantages of sulfites can be realized.
Thioether compounds have been reported to improve bleaching effectiveness when present in bleach or bleach-fixing baths (for example, British Patent 933,008; U.S. Pat. Nos. 3,241,966; 3,767,401; 4,201,585; 4,695,529; 4,804,618; 4,908,300; 4,914,009; 4,965,176; and 5,011,763; and unexamined Japanese Patent Application JP 02-44,355 A). These references do not disclose the use of thioethers as fix accelerators.
U.S. Pat. No. 4,960,683 of Okazaki et al. describes a method for processing black-and-white photosensitive materials comprising fixing a developed black-and-white spectrally sensitized photographic material in the presence of an aliphatic thioether compound and/or a heterocyclic thiol or thiolate compound. There is no indication that such compounds are useful with sulfite fixing solutions.
The use of ammonium thiocyanate, thiourea, or a thioether (e.g. 3,6-dithia-l,8-octanediol) to accelerate fixing by ammonium thiosulfate is mentioned in U.S. Pat. No. 5,002,861. There is no indication that these compounds are useful with other fixing agents, such as sulfite.
SIR H953 describes a method of processing color photographic materials in which thioether-containing compounds are present in a fixer bath which immediately follows a bleaching bath containing ammonium 1,3-diaminopropanetetraacetatoferrate(III) as the bleaching agent. The reported result of such a process is the improved bleaching of the developed silver in the photographic material. There is no mention of using such compounds with a sulfite fixing agent.
There remains a need for materials or methods that increase the speed of fixing of silver chloride photographic recording materials. Further, there remains a need for materials or methods that increase the fixing speed of sulfite fixers, so that improved processing ecology can be achieved.

Acceleration of silver removal by thioether compounds in sulfite fixer


The ion implantation method includes setting an ion beam scanning speed and a mechanical scanning speed of an object during ion implantation using hybrid scan in advance and implanting ions based on the set ion beam scanning speed and the set mechanical scanning speed of the object. In the setting in advance, each of the ion beam scanning speeds is set based on each of ion beam scanning amplitudes changing severally according to a surface outline of an object which is irradiated with the ions so that an ion beam scanning frequency is maintained constant for any of ion beam scanning amplitudes, and the mechanical scanning speed of the object corresponding to the ion beam scanning speed is set so that an ion implantation dose per unit area to be implanted into the surface of the object is maintained constant.

1. Field of the Invention
The present invention relates to ion implantation, and more particularly, to an ion implantation method and an ion implantation apparatus.
2. Description of the Related Art
In semiconductor manufacturing processes, a process for implanting ions into a semiconductor wafer is performed in a standard procedure for the purpose of changing conductivity, changing a crystalline structure of the semiconductor wafer, or the like. An apparatus used in this process is generally called an ion implantation apparatus.
The ion implantation apparatus is configured so that, for example, an ion source, an extraction electrode, a mass analysis magnet device, a mass analysis slit, an acceleration/deceleration device, a wafer processing chamber, and the like are arranged along a beamline so as to implant ions into a wafer which is a semiconductor substrate.
In general, since the cross-sectional area of an ion beam with which a wafer is irradiated is smaller than the size of the wafer, several irradiation methods for irradiating the entire surface of the wafer with the ion beam have been contrived. As an example of the irradiation method, there is a known method of performing ion implantation on the entire surface of the wafer by scanning the wafer with an ion beam in one direction and allowing the wafer to be reciprocally scanned in the direction perpendicular to the ion beam scanning direction.
In addition, as one of means for controlling an implantation dose in an ion implantation area, there is a contrived ion implantation apparatus where a plurality of ion beam detectors performing current detection in an X-direction (ion beam scanning direction) are installed behind a platen mounting wafers and an automatic X-scanning width controller automatically controlling an X-scanning width and an automatic Y-scanning speed controller automatically controlling a Y-scanning speed (wafer movement speed) are included.
In addition, similarly, as another means for controlling an implantation dose in an ion implantation area, there is a contrived method of measuring a beam current amount during ion implantation and automatically correcting and tracking a Y-direction (wafer movement direction) speed of a mechanical scanning device based on the measured beam current amount.

Ion implantation method and ion implantation apparatus


A stand-alone electronic measuring instrument for measuring AC (alternate current) power parameters on a utility distribution system wherein the measurement results are communicated telephonically to a facsimile device. Well-known techniques are used to acquire and accumulate analog signals representative of voltages and currents on an AC power system and digital signals. If the signals exceed a programmed threshold, or if an interval of time elapses, or if some other triggering even occurs, the instrument prepares a bit-mapped digital report on its accumulated input signals which may contain text, graphics, or both. The instrument then employs well-known techniques to telephonically transmit this report directly to a facsimile receiver without employing an intervening computer system.

1. Field of the Invention
This invention relates to electronic measuring apparatus. More specifically, this invention relates to a stand-alone electronic measuring apparatus for utility AC power systems incorporating analog voltage and current inputs, digital inputs, trigger event processing, and coupling to telephonic facsimile apparatus without an intervening computer system.
2. Background of the Invention
It is often necessary to read the results of an instrument on a utility power distribution system at some distance from where it is located. For example, the power flow through a particular transformer may be read by an operator at an office miles away, or the power factor of a branch circuit leaving a substation may be checked electronically without physically visiting the substation. Early remote instruments were connected to their output devices by direct cables. More recent instruments may employ communication techniques such as power line carrier, radio transmission, or the telephone switching network to transmit their readings.
If an instrument is read frequently enough, it may be appropriate to install a remote output device that is dedicated to the instrument. But if the information from the instrument is required infrequently, it is common practice to employ an output device, typically a computer, that can be shared between several instruments. For example, a single personal computer can easily be employed to occasionally interrogate and report on the status of several power quality instruments on a single power distribution network. This approach works well with many kinds of measurements.
However, if the instruments are a trigger-type instruments (that is, they are instruments that need to report their data at unpredictable intervals) with limited ability to store the measurements, a remote output device, typically a personal computer, must be standing by at all times to receive the measurements, or data may be lost. For example, if the instrument is an AC power system lightning strike recorder with sufficient storage space for data about a single lightning strike, and it records a strike, it must either be able to communicate its measurements to its remote output device before it detects a second lightning strike or lose its data about subsequent lightning strikes.
At utility companies, it is often difficult to economically justify dedicating a personal computer to standby communications from instruments, especially if the communication are infrequent. Even when a personal computer can be justified, it is often difficult to economically justify the associated outside telephone line required for that computer.
In some systems, such as the one disclosed by French et al. in U.S. Pat. No. 5,061,916, the output of remote instruments in a building automation system are coupled to a central control computer which in turn generates and transmits a report to a standard facsimile apparatus. This approach succeeds in remotely presenting the data collected by the instruments, but does not succeed in eliminating the requirement to dedicate a personal computer and its associated communication network to standby communications from instruments.
When making remote AC power system measurements, it is often necessary to check the measured data at an arbitrary time. For example, a utility company may receive an urgent telephone call from a customer requesting information about power line disturbances that have taken place in the last fifteen minutes. In situations like this, the user of a remote AC power measurement system may need to request that the remote sensor provide a report immediately, whether or not any triggering event has occurred.
The French reference does not disclose any method for instructing their building automation system to generate a report in response to a request signal.
The present invention solves the problem of requiring a standby computer by coupling the output of a remote AC power instrument directly to a facsimile apparatus via the telephone system without an intervening computer.
The present invention solves the problem of generating a report in response to a request signal by instructing the remote instrument to generate and transmit a report whenever it receives a phone communication that it cannot otherwise process, thus allowing a user to trigger a report by simply telephoning the instrument, waiting for it to answer, then hanging up.

Electronic remote data recorder with facsimile output for utility AC power systems


Granular absorbent products with low amounts of paper fiber are described. The absorbent products are made from recycled paper and include less than about 10% of paper fibers having a length sufficient to be retained on a 100 mesh screen. A process for making such granular absorbent products is also provided. The granular absorbents are useful for absorbing liquids spilled on the floor, and are crushable when walked on to provide greater resistance to slipping, and yet have a high resistance to attrition.

When paper such as ledger or magazine paper is recycled by first breaking the paper down into a pulp slurry containing its individual components, long cellulose fibers are recovered that are useful for making tissue or other paper products. The slurry also contains a significant amount of other materials including primarily kaolin clay and short cellulose fibers which are not useful for making tissue. In an effort to make the maximum use of materials in the pulp slurry, various products have been developed.
One of the products that has been developed is a granular absorbent product that is made by a process that is known as the KAOFIN process and is described in U.S. patent application Ser. No. 08/852,419, filed May 8, 1997, now U.S. Pat. No. 5,882,480 which is incorporated herein by reference for its disclosure of the process for making absorbent granules. The granular product of this process is described in our copending applications, Ser. No. 08/857,302 filed May 16, 1997 now U.S. Pat. No. 5,807,465; and Ser. No. 08/929,601 filed Sep. 19, 1997, now U.S. Pat. No. 5,888,345 which are incorporated herein by reference for a disclosure of the granular absorbent product made by the KAOFIN process.
Desirable characteristics for granular absorbent products include a high rate of absorption of liquids, a high bulk density, and a high resistance to attrition. For example, U.S. Pat. No. 4,343,751 (the '751 patent) discloses a process for making absorbent pellets from clay that may be used as a floor absorbent. The '751 patent discloses the use of paper sludge in amounts between ten percent and fifty percent of the total mass of the agglomerated solids. However, the absorbency is less than ideal as seen in the examples which include pellets having 50% paper sludge and 50% clay fibers, a bulk density of 38 lbs/ft and only 78% absorbency (see Chart 2, sample 008).
Another example is disclosed in U.S. Pat. No. 5,019,564 (the '564 patent) which is directed to non-clay agricultural granules. The granules are formed by the agitative agglomeration of a plant fiber slurry and resembles a clay granule in all respects except for its chemical inertness.
Clay products, such as those described in the '751 patent, have the disadvantage of low absorbency when mixed with paper sludge, and relatively high attrition rates when the fiber content is low, as described in the '564 patent. When used as a floor absorbent, it is desirable that the granules retain their integrity after absorbing water or oil from the floor.
Another problem encountered with granular floor absorbents is that the granules are generally spherical and tend to roll across the floor. When a worker steps on the granules, there is a danger that the granules will cause the worker to slip and fall as the granules roll under his shoes.

Floor absorbent granular product comprising kaokin clay and cellulose fibers


A support frame removably engageable with a wheelchair using no fasteners or tool-requiring engagement components. The support frame is slidably engaged and disengaged to the wheelchair by vertical translation. In an engaged position the weight of the support frame and anything attached thereto is born entirely by the rigid frame of the wheelchair through a positioning of support members of the frame in a frictional engagement atop the push handles of the wheelchair. So engaged, the support frame allows for easy transfer to other wheelchairs or easy removal and engagement from a collapsible wheelchair prior to or after transport of the wheelchair in a car or vehicle.

1. Field of the Invention
This application claims priority to Provisional Application No. 61/441,163 filed on Feb. 9, 2011, and incorporated herein in its entirety by reference.
The present invention relates to headrest and support assemblies and, more particularly, to a removably engageable headrest and support assembly configured for operative engagement with a wheelchair. The disclosed device is adapted to removably engage and support the weight of the headrest device itself and anything additionally engaged thereon, securely upon the handles of the chair. So supported, the device is easily disengageable for storage or for an engagement to another chair with a simple sliding engagement and no tools.
2. Prior Art
It is estimated that 1.5 million Americans residing outside of medical institutions employ manually operated wheelchairs. Reasons for wheelchair use can range from temporary injury rehabilitation to life long use from birth or after a severe injury. Users of wheelchairs are continually maintained in a seated position over extended periods of time and are offered only limited mobility. As such, wheelchair users as well as their loved ones often desire to provide the wheelchair user with the most comfortable seating experience possible.
Comfortable and ergonomic headrests in conventional chairs and other seated arrangements are extremely important for proper head and neck support where improper positioning and use can cause pain and even long term damage. This is even more true for wheelchair users who experience limited control of the neck muscles. When wheelchairs are used for temporary patient rehabilitation or when they are permanent fixtures of a person's life, the importance of proper head and neck support can make a huge difference in the person's recovery and overall quality of life.
Unfortunately, a conventional manual as well as motorized wheelchair available to the average consumer consists of a seating platform and backrest, and more often than not no specific neck or head support. Manual versions of such a chair are considered the bare minimum of medical technology for the patient and usually what insurance will buy. Without insurance such manual versions of wheelchairs are most affordable and available to average consumers.
Advancements in modern medical technology, however, have driven the evolution of the wheelchair to provide some support and some increase in the quality of life for individuals who would otherwise be fully incapacitated. These chairs can provide full body support, including neck and head, employ hydraulics and motors, and can have the ability to position the user in the standing position. Such adaptation with technology tends to increase costs, producing some with price tags in the tens of thousands of dollars. These types of chairs are employed by severely incapacitated users.
To the average consumer, be they significantly injured or just recovering from knee surgery, such expensive motorized chairs are simply unattainable. As a result, many consumers attempt to modify the conventional canvas or material supported wheelchair with attachments to fill certain needs. Head and neck support is one of those needs most sought after.
Some prior art efforts in headrest attachments are seen in full force. For example U.S. Pat. No. 3,643,996 to Carnahan, U.S. Pat. No. 4,989,836 Hudson III et al., U.S. Pat. No. 5,074,574 to Carwin, U.S. Pat. No. 5,308,028 to Kornberg, and U.S. Pat. No. 5,791,735 to Helman teach headrest assemblies that are engageable to a wheelchair, often to the structural elements such as the frame, handles, or other rigid element in a manner that does not disturb the seating or backrest platforms.
U.S. Pat. No. 4,498,704 to Hildreth teaches a slidably and removably engaged headrest assembly for a wheelchair. Although providing convenient means for removability as well as maintaining simplicity, the headrest of Hildreth is supported by a less than rigid fabric backrest of the wheelchair. Support is therefor limited to the condition and tensile strength and stretched condition of the fabric providing the backrest. Even sturdy reinforced fabric backs, after extended periods of time, can become uncomfortable if not painful to users and are in no manner adapted to support weight vertically downward.
The available devices to provide such support, however, require complex assembly with permanent or mechanical engagement of many components. The need for employment of such complicated and permanent engagement means does not easily permit removable engagement in a hospital, convalescent home, the user's home, or other settings where wheelchairs are used from patient to patient, or when neck and head support is temporarily undesirable.
Additionally, many lower cost fabric based wheelchairs collapse for transport in a vehicle or storage, and then must be expanded for use. Consequently, any device engageable to the wheel chair for head support and to support and communicate the weight of luggage, bags, or other items to the chair, must also engage with the chair and collapse, or be disengageable quickly, and without tools when the chair is to be collapsed. Once collapsed and then re-enlarged, such a device must be easily re-engaged to the chair, and then allow attachment of luggage, and coats, and purses and the like thereto so that the user or caregiver need not have to carry it at the same time as navigating with the wheelchair.
As mentioned, for many wheelchair users the chair additionally provides a means to transport their belongings such as purses, bags, backpacks, or luggage. The user conventionally places their belongings on their lap, or if possible, hangs the bag or other belongings off the push handle located on the rear of the chair. However, belongings positioned on the user lap may further limit the mobility of the user especially if the user does not have aid from a caregiver to propel the chair. Further, many chair styles do not offer push handles or other means to securely engaged belongings. Consequently, users and/or caregivers must somehow move the wheelchair while also carrying or somehow supporting their luggage, purses, coats, and other items that move with the patient which can be quite difficult and dangerous.
As such there is a continuing and unmet need for an improved removably engageable headrest and transport assembly for a wheelchair. Such a device should be easily assembled, and more importantly be easily engageable and disengageable, to any of a plurality of wheelchairs. Such a device should provide this means for easy engagement to allow for easy transfer to another chair or to allow the chair to be collapsed and re-enlarged again. Importantly, such a device should anticipate engagement to a fabric-based chair and should be configured with a contact means to the chair, whereby the weight of the device and anything attached to it is fully supported by the rigid frame without tools.
Further, such a device once engaged, should be selectively adjustable for supporting a user's head support needs as well as adapted to slidably engage upon a wide variety of wheelchairs. Finally, in so doing, such a device must still provide weight support through a contact with the frame of the chosen chair, and do so without tools or compression fittings. The device should also engage in such a manner to maintain the ergonomic comforts provided by the wheelchair to which it is engaged.


A control apparatus for a hydraulically operated vehicular transmission has a plurality of hydraulic engaging elements including a first hydraulic engaging element which is kept engaged in a plurality of transmission trains. The control apparatus has an accumulator which is connected, via a branched oil passage, to a working oil passage which is communicated with the first hydraulic engaging element. It also has a control valve which is disposed in the branched oil passage and which can be moved between a first position in which an upstream portion of the branched oil passage on a side of the first hydraulic engaging element and a downstream portion of the branched oil passage on a side of the accumulator are brought into communication with each other and a second position in which the communication is shut off. It further has an oil discharge passage which is connected to a second hydraulic engaging element when the second hydraulic engaging element is disengaged. This oil discharge passage is arranged to be connected to the downstream portion of the branched oil passage in the second position of the control valve.

1. Field of the Invention
The present invention relates to a control apparatus for a hydraulically operated vehicular transmission which has a plurality of hydraulic engaging elements.
2. Description of Related Art
In a hydraulically operated transmission for use in a vehicle such as an automobile, it is normal practice to effect the speed changing or shifting by controlling the engaging or disengaging of a plurality of hydraulic engaging elements. In this case, unless an appropriate control is made of a simultaneous engagement of a hydraulic engaging element to be engaged and a hydraulic engaging element to be disengaged at the time of speed changing, there will occur speed-change shocks (i.e., shocks at the time of speed shifting). As a solution, the following arrangement is disclosed in Japanese Published Unexamined Patent Application No. 180756/1988. Namely, an accumulator is provided in parallel with each of the hydraulic engaging elements, and an oil discharge control valve is provided in an oil discharge passage that is connected to the hydraulic engaging element to be disengaged. The pressure decrease in the hydraulic engaging element to be disengaged is buffered or cushioned by the accumulator that is parallelly connected thereto and causes a simultaneous engagement to take place. Once the hydraulic oil pressure in the hydraulic engaging element to be engaged has increased to a certain degree, the oil discharge control valve is opened to rapidly decrease the hydraulic oil pressure in the hydraulic engaging element to be disengaged, thereby preventing an excessive simultaneous engagement.
If one accumulator must be provided for each of the hydraulic engaging elements as in the above-described conventional example, there is a disadvantage in that a large number of accumulators are required and consequently that the control apparatus becomes large in size.
By the way, in the above-described conventional example, there is interposed in the first-speed transmission train a one-way clutch which allows for overrunning of the output side. The first-speed transmission train is thus established by engaging the hydraulic engaging element for the first-speed transmission train and, while this hydraulic engaging element is kept engaged, other hydraulic engaging elements are respectively engaged to thereby establish the other transmission trains. As described above, in the transmission provided with a hydraulic engaging element that is kept engaged in a plurality of transmission trains, the accumulator for that particular hydraulic engaging element will always be kept in a condition of pressure accumulation.
Taking note of this point, the present invention has an object of providing a control apparatus in which the pressure decrease characteristics at the time of disengagement of other hydraulic engaging elements can be controlled by the accumulator for the hydraulic engaging element that is always kept engaged, thereby making it possible to decrease the number of accumulators to be used.

Control apparatus for hydraulically operated vehicular transmission


A seat slide device which includes a lower rail fixed to a vehicle floor, an upper rail fitted into the lower rail to be slidable relative to the lower rail for supporting a seat, a lock device for fixing the upper rail at an arbitrary position of the lower rail, a lock lever provided in the lock device and rotatably supported on the upper rail, a lock bore formed on the lower rail, a pawl provided on the lock lever for being able to be inserted into the lock bore, and an energy absorbing bore provided on the lower rail and arranged in series with the lock bore and separated from the lock bore by a predetermined distance.

Known vehicle seat slide device includes a pair of lower rails fixed to a vehicle floor, a pair of upper rails fitted into the lower rails to be slidable in the longitudinal direction relative to the lower rails and supporting a seat, and a lock device for maintaining each lower rail and upper rail to be fixed. Japanese Patent Laid-Open Publication No. H11-348627 discloses a known vehicle seat slide device which includes a pair of lower rails having U shaped cross section and a pair of upper rails having approximately reversed T shaped cross section. In the construction of the known vehicle seat slide device according to Japanese Patent Laid-Open Publication No. H11-348627, a bottom portion of the upper rail is inserted into the lower rail and engages with opposing side wall portions of the lower rail via rollers and shoes. A plurality of lock bores are provided on one of the opposing side wall portions of the lower rail in series with a predetermined distance one another. An engaging piece of a lock lever pivotally supported by a bracket fixed to the upper rail is inserted into lock bores provided on the bracket, the side wall portion of the lower rail, and the bottom portion of the upper rail. Under a state that the engaging piece of the lock lever is inserted into the lock bores of the bracket, the sidewall portions of the lower rail, and the bottom portions of the upper rail, the lock lever is supported on two points thereof by the upper rail side. And the lock lever opposes to the lock bore of the lower rail at a portion between the two supported portion thereof. Thus, when the impact force is applied to the seat upon the frontal or rear collision of the vehicle, shearing stress is generated on both of contact portions between the lock lever and the lock bore of the lower rail.
The lock lever is made of a plate member having an L shape in cross section, and a horizontal plate part of lock lever is the engaging piece which includes either two pawls or three pawls. The pawls are inserted into each lock bore. Thus, when the impact is applied on the seat, the horizontal plate part hits on an upstanding plate part of the lock bore of the lower rail, and the sharing force is generated on and shears the upstanding plate part. The impact force is absorbed by the shearing and mitigated effectively, and the drop out of the seat from the lower rail is prevented.
Because the strength of the upstanding plate part of the lower rail having the lock bores is determined to be lower than the strength of the plane plate of the lock lever, the engaging piece which is the horizontal plane plate of the lock lever is consecutively entering adjacent lock bores while breaking the upstanding plate portions of the lower rail to absorb the impact energy.
In the configurations of H11-348627, the lock bores of the lower rail are only provided on portions necessary for adjusting the seat position in the longitudinal direction of the vehicle. This prevents the undesired lock of the seat at the undesired position and further ensures the strength of the opposing sidewall portions of the lower rail. Notwithstanding, when the engaging piece of the lock lever is inserted into either at a front most or rear most position of the lock bore, when the horizontal plate portion serving as the engaging piece of the lock lever is broken by the impact force, the seat posture may suddenly and significantly be changed, because there is no adjacent lock bores to absorb the impact applied to the seat either by the collision from the front or the collision from the rear.
A need thus exists for a vehicle seat slide device which securely absorbs the impact due to the collision from the longitudinal directions.


A master cylinder including a cylinder having one end open to the outside. A secondary piston guide ring, a sleeve and a primary piston guide ring are adapted to be fitted in this order into the cylinder from the one open end. A piston is slidably fitted in an axial direction of the cylinder, into each of the secondary piston guide ring, the sleeve and the primary piston guide ring. A retainer is provided at the open end of the cylinder, and adapted to abut against the primary piston guide ring so as to prevent escape of the primary piston guide ring from the cylinder. An elastic member is provided between a rearward end portion of the sleeve and a forward end portion of the primary piston guide ring.

The present invention relates to a master cylinder which generates a fluid pressure for operating a brake.
As an example of a conventional master cylinder, there can be mentioned that which is disclosed in Unexamined Japanese Patent Application Public Disclosure (Kokai) No. 2-136363.
This master cylinder comprises a cylinder having one end open to the outside and the other end closed, and a secondary piston and a primary piston slidably disposed at a forward position (on a side of the closed end) and a rearward position (on a side of the open end) in the cylinder. Each piston forms a pressure chamber between itself and the cylinder, so as to generate a fluid pressure. A secondary piston guide ring, a sleeve and a primary piston guide ring are slidably fitted into the cylinder, in this order, from the open end to be provided at the forward position, a central position and the rearward position in the cylinder, respectively. A holder which abuts against the primary piston guide ring is provided at the open end of the cylinder to prevent escape of the primary piston guide ring, the sleeve and the secondary piston guide ring from the cylinder.
The secondary piston guide ring and the primary piston guide ring are adapted to axially and slidably guide the secondary piston and the primary piston. Each piston guide ring forms a fluid supply chamber between itself and an outer circumferential surface of the piston. The piston guide ring includes a communication port having one end open to the fluid supply chamber and the other end open at an outer circumferential surface of the ring. Further, the sleeve forms communication passages which allow communication between the communication ports of the secondary and primary piston guide rings and a reservoir.
However, the conventional master cylinder of Kokai No. 2-136363 has the following problems.
In this master cylinder, to prevent an excessive assembly load acting on the primary piston guide ring, the sleeve and the secondary piston, and to prevent axial play of these elements, an elastic member is provided between the secondary piston guide ring and the sleeve. However, in the case that a large force is applied in a braking operation, the sleeve moves toward the open end of the cylinder under the effect of fluid pressure generated by the primary piston, which is moved toward the closed end of the cylinder by a brake pedal. More particularly, fluid pressure works in the gap between the rear end of the secondary piston guide ring and the forward end of the sleeve where the elastic member is clamped, to thereby urge the secondary piston guide ring forwardly toward the closed end of the cylinder and the sleeve rearwardly toward the open end of the cylinder, respectively. Consequently, the play is not completely eliminated and the holder is pressed and instantaneously deformed. To prevent such deformation, the holder must be manufactured using an expensive high strength material, and be provided with a sufficient wall thickness. Accordingly, not only are costs increased but the size of the master cylinder must be increased to accommodate the extra wall thickness.
To overcome these problems, the present invention has been made. It is an object of the present invention to provide a low-cost, reduced size master cylinder in which deformation of a holder is prevented and a play of a sleeve is eliminated.
The present invention provides a master cylinder comprising a cylinder having one end open to the outside. A secondary piston guide ring, a sleeve and a primary piston guide ring are adapted to be fitted in this order into the cylinder from the one open end. A piston is slidably fitted in an axial direction of the cylinder, into each of the secondary piston guide ring, the sleeve and the primary piston guide ring. A retaining member is provided at the open end of the cylinder, and adapted to abut against the primary piston guide ring and prevent escape of the primary piston guide ring from the cylinder. An elastic member is provided between a rearwardly facing surface or rearward end portion of the sleeve and an associated forwardly facing surface or forward end portion of the primary piston guide ring.
Thus, in the present invention, the elastic member is provided between the sleeve and the primary piston guide ring. Therefore, under generation of a large force in a braking operation, unlike in the prior art, the sleeve does not play either forwardly or rearwardly. Furthermore, since fluid pressure does not create significant force between the sleeve and primary piston guide ring, the holder is not subjected to significant force and, therefore, it need not be made particularly strong.


A configuration generates a clock signal from a digital signal by evaluating signal edges of the digital signal. A first device generates a pulse at a signal edge oriented in a first direction, and a second device generates a pulse at a signal edge oriented in a second direction being opposite the first direction. Each of the devices has one terminal for receiving a digital signal and one output. A voltage-controlled, triggerable oscillator device has at least two trigger inputs, one control input and one output. Each of the trigger inputs is connected to the output of a respective one of the first and second devices, and the output of the oscillator device is an output for the clock signal. An integration device has an input connected to the output of the oscillator device and has an output connected to the control input of the oscillator device.

1. Field of the Invention
The invention relates to a configuration for generating a clock signal from a digital signal by evaluating signal edges of the digital signal.
In digital signals, the logical values L and H are represented by different signal levels. A change in signal levels is carried out synchronously with a clock. In general, a signal level change does not occur upon each clock edge, so that the data clock cannot be detected directly from the digital signal. Due to delays, for instance during signal transmission or signal processing, the phase relationship and instantaneous frequency of the digital signal vary. However, processing the signal at the correct time in a digital signal processing apparatus requires a clock signal that has the same frequency, or a multiple of the instantaneous frequency of the digital signal, and has a fixed phase relationship with it.
German Published, Non-Prosecuted Application DE 35 15 542 A1 discloses a configuration for generating a clock signal from a digital signal by evaluating the signal edges of the digital signal. A signal at the frequency of the digital signal is already present. Only a readjustment of the phase is performed, in a digital control loop.
German Patent DE 35 43 826 C2 discloses a phase-locked loop that generates a frequency-coupled and phase-coupled output signal for a digital input signal. It uses a voltage-controlled but not triggerable oscillator, a phase detector, and a low-pass filter for that purpose. German Published, Non-Prosecuted Application DE 37 28 022 A1, corresponding to U.S. Pat. No. 4,803,705, shows a further phase-locked loop, which includes a voltage-controlled, non-triggerable oscillator, as well as a phase detector and a frequency detector.
2. Summary of the Invention
It is accordingly an object of the invention to provide a configuration for clock recovery, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and which generates a clock signal from a digital signal that is coupled to the phase and the frequency of the digital signal.
With the foregoing and other objects in view there is provided, in accordance with the invention, a configuration for generating a clock signal from a digital signal by evaluating signal edges of the digital signal, comprising first means for generating a pulse at a signal edge oriented in a first direction, and second means for generating a pulse at a signal edge oriented in a second direction being opposite the first direction, each of the means having one terminal for receiving a digital signal and one output; a voltage-controlled, triggerable oscillator device having at least two trigger inputs, one control input and one output, each of the trigger inputs being connected to the output of a respective one of the first and second means, and the output of the oscillator device being an output for a clock signal; and an integration device having an input connected to the output of the oscillator device and having an output connected to the control input of the oscillator device.
In accordance with another feature of the invention, each of the means include one D flip-flop having an output being fed back to a reset input, a clock input being connected to the terminal for the digital signal and a data input being controlled by a logical level, and one of the means having an inverter connected between the clock input and the terminal for the digital signal.
In accordance with a further feature of the invention, the oscillator device is a ring oscillator including a delay device having an adjustable delay time and having an output being fed back inverted to an input, and the ring oscillator includes an NOR gate having an output being connected to the input of the delay device and to the output of the oscillator device and having inputs being connected to the output of the delay device and to the trigger inputs of the oscillator device.
In accordance with an added feature of the invention, the delay device includes a series circuit of at least one delay element having a fixed delay time and at least one delay element having an adjustable delay time.
In accordance with an additional feature of the invention, there is provided a divider device having an input connected to the output of the oscillator device and an output connected to the output for the clock signal.
In accordance with yet another feature of the invention, the divider device has a reset input connected to the output of one of the means.
In accordance with yet a further feature of the invention, the integration device is an analog resistor capacitor configuration.
In accordance with a concomitant feature of the invention, the integration device includes an up-down counter having a control input for a switchover between up and down counting being connected to the output for the clock signal and having an output, and the integration device includes a digital/analog converter being connected downstream of the output of the counter and having an output being the output of the integration device.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a configuration for clock recovery, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.


An array resistor network that has a high density of resistors per unit area. The array resistor network includes a ceramic substrate having a top and bottom surface. Apertures extend through the substrate between the top and bottom surfaces. Recesses are located on opposite edges of the substrate. Resistors are located on the top surface. Each resistor is located between a recess and an apertures. Inner conductors are connected to one end of the resistors. The Inner conductors are located on the top surface and extend through the aperture onto the bottom surface. Outer conductors are connected to another end of the resistors. The outer conductors are located on the top surface and extend along the recess onto the second surface.

1. Field of the Invention
This invention generally relates to resistors for electronics. Specifically, the invention is a group of resistors mounted in a high density network or array package.
2. Description of the Related Art
Resistor networks are commonly used to terminate high speed digital signal lines to minimize unwanted reflections back through the transmission structure which is typically a printed circuit board. In most applications, the terminations are made by placing a resistor with a resistance matching the impedance of the transmission line, at the end of the transmission line. One end of the resistor is connected to a common termination voltage and the other end is connected to the signal line. For these applications, a bussed resistor network is a convenient solution, since one end of the termination is common to all signal lines.
The previous resistor network designs include surface mount, through hole SIP and DIP versions and chip resistor arrays.
Despite the advantages of each type of prior art resistor network, there is still difficulty in economically manufacturing resistors with a high density of interconnects per unit area. In particular, providing electrical connections only on the periphery of the resistor network causes the electrical leads to be tightly spaced on the edge of the device, while the area in the interior of the device is unused for electrical interconnections.
Therefore, there is a current unmet and heretofore long felt need for a resistor network with higher density that can be manufactured at low cost.
It is a feature of the invention to provide an array resistor network that has a high density of resistors per unit area.
It is a feature of the invention to provide an array resistor network that includes a substrate that has a first and a second surface and first, second, third and fourth edges. Several apertures extend through the substrate between the first and second surfaces. Several recesses are located in the first and second edges. Several resistors are disposed on the first surface. Each resistor is located between the recess and the apertures. Several first conductors are connected to a first end of the resistors. The first conductors are located on the first surface and extend through the aperture onto the second surface. Several second conductors are connected to a second end of the resistors. The second conductors are located on the first surface and extend through the recess onto the second surface.