Abstract: A core component is disclosed. In an embodiment, the core component includes at least one edge that has a transition, wherein the transition is asymmetrical.

Abstract: Inductor core including: a base core portion having a first surface and an opposite second surface; an inner core portion extending from the first surface in a direction transverse to the first surface; an outer core portion extending, in the direction transverse to the first surface, from the first surface to an end surface of the outer core portion, the outer core portion at least partly surrounding the inner core portion, thereby forming a space around the inner core portion for accommodating a winding; wherein the first surface includes a recess for accommodating a connection portion of the winding, said recess extending at least a part of a distance between the inner core portion and the outer core portion, and wherein the outer core portion presents a slit extending from said end surface towards the recess, and wherein the second surface comprises a first protrusion oppositely arranged to the recess.

Abstract: In one aspect of the invention, an off-circuit tap changer includes a switch base and a rotation shaft penetrating the switch base. An upper end of the rotation shaft is connected to an operation positioning device, a lower end of the rotation shaft is disposed with moving contacts, and fixed contacts corresponding to the moving contacts are circumferentially disposed at a spacing on the switch base; the moving contacts are radial elastic rolling moving contacts, and the radial elastic rolling moving contacts span between two adjacent fixed contacts and closely contact the fixed contacts.

Abstract: The present invention provides a heating unit capable of easily and inexpensively adjusting total impedance based on tire mold size so that a power source can be used at a high power factor, and a tire heating apparatus using the same. A ferromagnetic metallic member 10a heats a tire mold M1 by heat conduction. An induction heating coil C1 is disposed on the side of the ferromagnetic metallic member 10a opposite the tire mold M1 to induction-heat the ferromagnetic metallic member 10a by generating magnetic field lines. A nonmagnetic conductor 30a is disposed on the side of the induction heating coil C1 opposite the ferromagnetic metallic member 10a to shield the magnetic field lines generated by the induction heating coil C1. A heating unit 100a including these elements heats the tire mold M1 storing a tire.

Abstract: A novel coupler, coupler housing and ferrite core and associated elements and concepts thereof and therefor for use in particular with an Inductive Power Transfer or Distributed Power System.

Abstract: A compact position sensor with high operational reliability is provided. This sensor has a tubular detection coil, a magnetic core movable in the detection coil, a drive circuit for the detection coil, a signal processing circuit for converting a change in impedance of the detection coil into an electric signal, and a guide means for guiding a movement of the magnetic core in the detection coil. The guide means has a guide portion connected to the magnetic core and a support portion for slidably supporting the guide portion. The magnetic core can be smoothly displaced in the detection coil without contacting an inner surface of the detection coil by a sliding movement of the guide portion relative to the support portion.

Abstract: A scale loop formed by a loop trace of electrically conductive material is usable in an induced current position transducer. The scale loop is continuous and has a particular shape depending on the configuration of the induced current position transducer. The scale loop is not in contact with other highly conductive materials. The dimensions of the cross-section of the conducting trace are chosen to increase the transfer of energy through the transducer.

Abstract: A differential pulse transformer having a drive coil (10a) and differential sense coils (10b) are disposed on a planar surface with a target (10e, 10f) movable over the sense coils to cause an imbalance in magnetic field when a large di/dt pulse is generated in the drive coil. A detection circuit senses the imbalance and provides a digital output accurately identifying the position of the target. Coil and target embodiments include relatively small secondary coils and relatively long targets (10b, 10e/10f; 12b, 12e/12f and 14b) and relatively large secondary coils and short targets (16b, 16c; 18b, 18c; 20b and 22b).

Abstract: A electromagnetic induction-type absolute position transducer according to the present invention has a plurality of scale loops functioning as coils. The scale loop has first and second loop portions and a connecting pattern portion which connects the corresponding first and second loop portions with each other. The first and second loop portions are arranged along the measuring axis at different wavelength intervals. At least part of the pattern widths constituting scale loops are gradually increased as the length of a connecting pattern portion becomes longer.

Abstract: An inductive length measuring system which, by scanning a scale with a graduation of periodically variable reluctance and a coil system in a linear arrangement, can detect information relating to the position and/or the movement of the coil system with reference to the scale. The coil structure comprises a multi-ply arrangement of a combination of coils in the form of planar spiral windings or turns having a plurality of receiver pairs, each pair having two differentially connected receiver elements which can be interconnected for the purpose of signal generation for each of at least two measuring channels, and wherein at least one emitter element is provided which is inductively coupled to the receiver elements as a function of the relative position in the measuring direction relative to the measuring scale, thereby generating at least one output signal which is compensated for offset and/or sinusoidal shape and/or amplitude.

Abstract: A scale and a detecting head each include input/output connectors. Either of the input/output connectors is connected to receiving-side connector. By connecting the receiving-side connector to either of the scale and the detecting head, which is fixed in use, there is no change that a receiving-side cable will be disconnected by movement of the counterpart of the fixed member. This results in improvement of the reliability. Additionally, device is operable at high speed since the cable does not restrict motion of the movable member.

Abstract: An electromagnetic induction position detector has a detection head and a scale which are placed so as to be opposed to each other with a predetermined gap in a relatively movable manner. The detection head has a driving coil which generates a primary varying magnetic flux, and a receiving coil which detects a magnetic pattern changed in a predetermined spatial period and in a direction of the relative movement. The scale 2 has a magnetic modulating section which modulates the primary varying magnetic flux to generate the magnetic pattern. The scale 2 has a plate-shaped resin substrate 30. Metal foil 61 of a predetermined pattern which prevents the resin substrate 30 from being expanded or contracted, and suppresses an eddy current formed on a face of the scale opposite to a face on which the magnetic modulating section is formed.

Abstract: The invention relates to a method for substantially temperature-independent detection of the position of a moving element (9) by way of an inductive position sensor (1), comprising a coil (5) and a core (4) movable within the coil, the position of said core in relation to the coil (5) being dependent on the position of said element (9), whereby a measurement of the inductance of said coil (5), corresponding to the core (4) position, is detected by connecting a voltage to said coil (5) and measuring the time period in which a current (i) through the coil (5) is changed between two predetermined levels. The method follows the steps of feeding a regularly alternating voltage to the coil (5), measuring the current (i) flowing through the coil (5), measuring the period of time (t1) needed for the current (i) to change from a first predetermined level (i1) to a second predetermined level (i2), and determining a measurement of the core (4) position through measuring the period of time (t1).

Abstract: A transducer is provided for use in a position sensor which senses the position of two relatively movable members. In one form, the transducer has a plurality of sensor windings having a number of loops arranged in succession and connected in series so that signals induced in adjacent loops by a common electromagnetic field oppose each other and an excitation winding having at least one loop super-imposed on but electrically isolated from the loops of the sensor windings.

Abstract: The present invention is intended to provide a ultra-precision high sensitivity displacement measuring device which has such a high resolution as to be able to make submicron measurement.

Abstract: A reduced offset absolute position transducer has at least one magnetic field generator that generates a first changing magnetic flux in a first flux region. A plurality of coupling loops have a first plurality of coupling loop portions spaced at a first wavelength along a measuring axis and a second plurality of coupling loop portions spaced at a second wavelength along a measuring axis. One of the first plurality of coupling loop portions and the second plurality of coupling loop portions are inductively coupled to a first changing magnetic flux from a transmitter winding in a first flux region to generate a second changing magnetic flux outside the first flux region in the other of the first plurality of coupling loop portions and the second plurality of coupling loop portions. A magnetic flux sensor is positioned outside the first flux region and is responsive to the second changing magnetic flux to generate a position-dependent output signal.

Abstract: A high-accuracy inductive absolute position transducer system has two members movable relative to each other and includes an amplitude modulating transducer including flux modulators of progressively varying properties. The amplitude modulating transducer includes a transmitter winding and at least one set of receiver windings. An amplitude modulating transducer has a plurality of flux modulator zones distributed along the measuring axis. Flux modulators are formed in at least some of the flux modulator zones. The properties of different flux modulators are varied so as to generate varied flux. A signal generating and processing circuit is connected to the transmitter winding. The flux modulators modulate the inductive coupling based on the relative position between the read head member and the scale member.

Abstract: An inductive absolute position sensor has at least one magnetic field generator that generates a first changing magnetic flux in a first flux region. A plurality of coupling loops have a first plurality of coupling loop portions spaced at an interval related to a first wavelength along a measuring axis and a second plurality of coupling loop portions spaced at an interval related to a second wavelength along a measuring axis. One of the first plurality of coupling loop portions and the second plurality of coupling loop portions are inductively coupled to a first changing magnetic flux from a transmitter winding in a first flux region to generate a second changing magnetic flux outside the first flux region in the other of the first plurality of coupling loop portions and the second plurality of coupling loop portions. A magnetic flux sensor is positioned outside the first flux region and is responsive to the second changing magnetic flux to generate a position-dependent output signal.

Abstract: An absolute position transducer system has two members movable relative to each other and includes a code track transducer and at least one fine wavelength transducer. The code track is arranged to form a sequential pattern of base-N code words, where N is greater than two (i.e., non-binary). Each sequential non-binary code word identifies an absolute position of one member with respect to the other at a first resolution. Alternatively, the code track is arranged to form a pseudo-random non-binary code word pattern. In this case, the transducer system compares a non-binary code word with a look-up table to determine an absolute position of one member with respect to the other at a first resolution. In order to generate a non-binary code word pattern, code track transducer employs different-sized flux disrupters, different-sized flux enhancers, or a combination of flux disrupters and enhancers.

Abstract: An inductive linear encoder (10) has a position sensor (1) and scale (2) which are movably disposed relative to each other. The sensor (1) is with a drive wire (3) to which an alternating current is supplied, and one set of detection wires (4a-4d) at right angles to the drive wire (3) in the same plane. The scale (2) is configured including an elongate substrate (7) having its surface on which a series combination of conductive closed loop patterns (8) are periodically arranged at equal intervals. These conductive closed loop (8) are linearly laid out on the substrate (7) in the relative movement direction. Each loop (8) consists essentially of a reception conductor segment (8a) and signal transmit conductor segments (8b, 8c) integral with the former (8a). The receive conductor segment (8a) is responsible for generation of an induced current due to a first variable magnetic field creatable from the drive coil (3).

Abstract: A device for measuring the displacement of stems of valves having a spindle coupled to a stem of a valve and provided with two inductive pickups; each inductive pickup is formed by a fixed part and a movable part constituting a variable inductor, which, following a displacement of the stem and a rotation of the spindle coupled thereto, generates an inductance variation of the electric circuit associated thereto; electronic excitation and detection means are adapted to convert the inductance variations into a pair of digital signals whose difference is indicative of the displacement of the stem.

Abstract: The proposed device comprises a primary detector and a measuring amplifier, the primary converter comprising a central cylindrical core and an external cylindrical core arranged coaxially along a longitudinal axis, a movable member being mounted coaxially with the cores, a measuring winding arranged on the central core along the longitudinal axis in such a manner that the turns of the winding encompass the central core in a transverse direction, and an additional winding having a common electrical connection point with the measuring winding and disposed on one of the cores so that its turns encompass the core in a longitudinal direction and pass through the corresponding central axial opening. The measuring winding and the additional winding are connected with the measuring amplifier, and alternating current voltage is fed to the input thereof.

Abstract: A compact, long-range inductive absolute position transducer system has two members movable relative to each other and includes a code track transducer and at least one fine wavelength transducer. The two members include a read head member and a scale member. The phase difference between the phase angles of two fine wavelength transducers may be used to generate an intermediate wavelength. Alternatively, the phase difference between the phase angles of one fine wavelength transducer and the code track transducer may be used to generate an intermediate wavelength. The code track includes sequential n-bit code words. Each sequential code word identifies an absolute position of one member with respect to the other with a first resolution. Each intermediate wavelength includes an integer number of code words greater than or equal to one. Using this relationship, the intermediate wavelength is used to identify the start position (start bit) of the appropriate code word.

Abstract: A sensor head is provided for use in a apparatus for indicating the position of a movable member relative to a fixed member. It has two multi-turn sensor windings, each including repetitive pattern of series connected alternate sense loops of conductor. One sensor winding is in spatial phase quadrature with the other sensor winding, and the arrangement of the windings is such that the mid points of the sensor windings coincide. The sensor head is particularly suited for use in indicating the position of a movable member relative to a fixed member as it is relatively insensitive to longitudinal tilt relative to the other member.

Abstract: A scanning element for a position measuring instrument. The scanning element includes a first scanning track disposed within a first region and a second scanning track disposed adjacent to the first scanning track within a second region. An electromagnetic field generator generates a homogeneous electromagnetic exciting field within the first region and the second region.

Abstract: A high-accuracy inductive absolute position transducer system has two members movable relative to each other and includes a code track transducer and may include a fine track transducer. The code track transducers includes a code track transmitter winding and at least one set of code track receiver windings. Each set of code track receiver windings includes n balanced pairs. Each balanced pair extends along the measuring axis and includes a positive polarity winding and a negative polarity winding. A code track has a plurality of flux modulator zones distributed along the measuring axis. Flux modulators are formed in at least some of the flux modulator zones. A signal generating and processing circuit is connected to the transmitter winding and each balanced pair. The code track transmitter winding and each balanced pair form an inductive coupling.

Abstract: An electronic linear scale having a reduced offset position transducer that uses at least one coupling loop on a scale to inductively couple a transmitter winding on a read head to one or more receiver windings on the read head. The transmitter winding generates at least one primary magnetic field. The transmitter winding is inductively coupled to first loop portions of the coupling loops by the primary magnetic field. Second loop portions of the coupling loops generate secondary magnetic fields. Each receiver winding is inductively coupled to the second loop portions of the coupling loops by the secondary magnetic fields. At least one of the transmitter winding or the receiver windings is formed in a periodic pattern complementary to the dimensions of the coupling loops. Prescribed winding configurations are used to reduce the effects of extraneous inductive coupling in the device.

Abstract: A reduced offset position transducer uses at least one coupling loop on a scale to inductively couple a transmitter winding on a read head to one or more receiver windings on the read head. The transmitter winding generates at least one primary magnetic field. The transmitter winding is inductively coupled to first loop portions of the coupling loops by the primary magnetic field. Second loop portions of the coupling loops generate secondary magnetic fields. Each receiver winding is inductively coupled to the second loop portions of the coupling loops by the secondary magnetic fields. At least one of the transmitter winding or the receiver windings is formed in a periodic pattern complementary to the dimensions of the coupling loops. Prescribed winding configurations are used to reduce the effects of extraneous inductive coupling in the device.

Abstract: An electronic linear scale, which uses an induced current position transducer, includes a slider assembly mounted adjacent to an elongated beam. The slider assembly is mounted on one mounting member of a device such as a machine tool. The elongated beam is mounted on a second mounting member of the device. The first and second mounting members move relative to each other. The position of the slider assembly on the beam is indicative to of the position between the first and second mounting members. Relative movement is determined by an inductive read head mounted on the slider assembly that couples to flux modulators on the beam. The read head includes a transmitter winding and a pair of receiver windings, preferably fabricated in a planar form, carried by a common printed circuit board. The flux modulators, which can include flux disrupters and/or flux enhancers, are carried by the beam and modulate the magnetic fields produced by the transmitter.

Abstract: A pitch-compensated induced current position transducer includes a scale having a plurality of scale elements arranged along a measuring axis and a read head positioned adjacent to and movable relative to the scale. The read head has a transmitter winding that generates a changing magnetic field and at least one receiver winding. One of the transmitter winding and receiver winding is formed from a spatially modulated section having an associated phase. The spatially modulated section has flux coupling areas distributed relative to a plurality of polarity zones. The spatially modulated section has at least one pitch balancing section. In one type of pitch balancing section the positive polarity winding loops and the negative polarity winding loops have their centroid axes aligned.

Abstract: An induced current position transducer has a multi-tap winding. The multi-tap winding allows for digital interpolation of position to a small fraction of a wavelength, thereby reducing the amount of analog interpolation performed by the transducer electronics. In addition, a multi-tap receiver winding enhances the total output signal strength, thereby allowing a smaller receiver winding length along the direction of the measurement axis. Furthermore, a multi-tap receiver winding exhibits low impedance, thereby improving the output signal time constant. The multi-tap receiver winding of this invention comprises a plurality of receiver winding loops offset with respect to each other along the measuring axis, and electrically connected in series. Preferably, the signal contributions of each loop combine to form a "vector circle".

Abstract: An inductive absolute position transducer system, usable in high accuracy applications such as linear encoders, has two members movable relative to each other and includes three inductive position transducers. Each inductive position transducer includes at least one transmitter winding for generating a magnetic field and two or more receiver windings for receiving the magnetic field. Each inductive position transducer also includes a plurality of flux modulators which modulate the magnetic field generated by the transmitter winding. Each receiver winding has a plurality of symmetric loops arranged along a measurement axis. The receiver windings of two of the inductive position transducers define two wavelengths that are similar to each other, but not equal. Thus, a phase relationship between the inductive position transducers has a wavelength much longer than the wavelength of either of the two inductive position transducers.

Abstract: A high-accuracy inductive absolute position transducer system has two members movable relative to each other and includes a code track transducer and may include a fine track transducer. The code track transducer includes a code track transmitter winding and at least one set of code track receiver windings. Each set of code track receiver windings includes n balanced pairs. Each balanced pair extends along the measuring axis and includes a positive polarity winding and a negative polarity winding. A code track has a plurality of flux modulator zones distributed along the measuring axis. Flux modulators are formed in at least some of the flux modulator zones. A signal generating and processing circuit is connected to the transmitter winding and each balanced pair. The code track transmitter winding and each balanced pair form an inductive coupling.

Abstract: The inductive displacement sensor includes a first element of cursor (31) and a second element or scale (32) exhibiting spatially periodic electromagnetic characteristics, such as windows (321) and traverses (322). The first element (31) has a series of windings, e.g., three interlaced meander windings (31A to 31C) and an electronic circuit being connected to the windings on the first element to bring about a current in at least one of the windings (31A) and to measure the influence due to the position of the second element's spatially periodic electromagnetic characteristics on the inductances of at least a part of the windings (31B, 31C) of the first element (31). Such a displacement sensor is simple, rugged, small, draws little current and is insensitive to water.

Abstract: A variable inductance device for indicating the position of one body relative to another includes primary and secondary windings which are mounted such that one is slidable over the other. The primary winding is wound on a body including annular channels for retaining the winding turns in an arbitrarily selectable turns distribution. The secondary is a shorted winding. A signal producing circuits electrically connected to the primary winding for producing a signal which varies with the device inductance. By selecting the turns distribution such that the device's inductance variation with position and the signal producing circuit's output variation with inductance complement each other, the output signal is made to vary as an arbitrarily selectable function of the position.

Abstract: In one aspect of the present invention, an apparatus for determining an extended length of a hydraulic cylinder is disclosed. A piston and rod are contained within a cylindrical housing of the hydraulic cylinder. A coil is wound about the rod and is attached to the piston and an end of the cylindrical housing. The coil extends and retracts with the reciprocating movement of the piston. An oscillator is coupled to the coil and produces a position signal in response to the inductance of the coil. A circuit receives the position signal, and determines the incremental linear position and velocity of the piston and rod relative to the housing in response to the frequency of the position signal.

Abstract: Position sensors for detecting the position of a linear motor relative to a platen are disclosed. In one embodiment, the sensor includes first and second magnetic members having teeth disposed relative to the teeth on the platen. A single turn planar drive winding is disposed around at least one of the teeth of the first and second magnetic members for producing a first and a second drive flux within each of the magnetic members. A single turn planar sense winding is disposed around at least one of the teeth of the first and second magnetic members for generating first and second outputs which are a periodic function of the position of the sensor relative to the platen. In another embodiment of the present invention, the sensor includes two magnetic members each having four pole pieces. A drive winding is disposed on each member for establishing first and second fluxes in each member which are symmetrical about a center of each member.

Abstract: A rotary sensing device for indicating the angular displacement of a shaft is disclosed which comprises a magnetic core member formed of ferromagnetic material, a first winding wound within the core member for producing a first magnetic field in a closed path throughout the core, a second winding wound around the core member for producing a second magnetic field in a closed path throughout the core, the first and second magnetic fields being orthogonal to each other, and a pick-up coil assembly associated with the magnetic core member, the magnetic fields, and the shaft for sensing angular displacement of the shaft. A proximity sensor for sensing the passage of an object and the direction of passage of the object is also disclosed.

Abstract: The sensor comprises a field coil generating a time-variant magnetic field, and sensor coils arranged inside the field coil, a rotatable device being arranged for modulating the magnetic flux passing through the sensor coil according to its angular position. Each sensor coil comprises a magnetically permeable core having a polar portion facing the rotatable device. A portion of a magnetically permeable sealing element is arranged facing the rotatable device on the opposite side from said polar portion. The air gaps between said polar portion and rotatable device, and between said portion of the sealing element and said rotatable device, are wholly located substantially within the field coil.

Abstract: A substantially C-shaped core which is used in a rotational position sensor of an inductance type. The core is formed of a sensing side portion and a referencing side portion, each of which has an arc shape. The centers of the arc shapes are spaced apart from one another at a predetermined distance, thereby extending a movable range of a movable short ring. As a result, a rotational position can be detected over a wider range of degrees. The core is also formed of a core intermediate portion, which has laminated thin plates therein, and core opposite end portions, which are disposed in a sealed state on the top and bottom surfaces of the core intermediate portion. The core intermediate portion and the core opposite end portions are welded together at given points so as to form a one-piece body. Surfaces of the core can thereby be prevented from being deformed or detached.

Abstract: A transducer system is provided including an inductive linear displacement transducer connected to a temperature-compensating signal processor. The signal processor includes (a) an amplitude-variable, frequency-stable device providing a modulated D.C. current through the transducer, (b) a temperature-sensitive element connected in series between the transducer and the current-providing device such that it is subjected to substantially the same temperature as the transducer, and (c) a signal processing circuit coupled to the temperature-sensitive element. The temperature-sensitive element has a high temperature coefficient so that temperature changes have a substantial effect on the DC offset of the signal coming from the temperature-sensitive element, and a low dynamic resistance so that temperature changes have substantially no effect on the amplitude of the signal coming from the temperature-sensitive element.

Abstract: A position sensing device including two spaced conductive coils constituting a primary and secondary winding of a transformer. A coupling member is mounted to a moveable object such as an automobile steering mechanism and moves relative the primary and secondary windings. This movement adjusts or alters the transformer coupling between the primary and the secondary and produces a variable output signal which can be correlated through use of appropriate circuitry to the position of the moveable member. Two alternate designs are disclosed. In a first design, the transformer primary and secondary are disposed side-by-side and the coupling member slips over the primary and secondary for relative linear movement. In a second design, the primary and secondary are disposed one within the other and the coupling member fits within a gap between the primary and secondary.

Abstract: A device for determining a length of linear movement of an angle of rotation of a machine part, and comprising spaced first and second bodies, a coil arranged on one of the first and second bodies, and a diaphragm connectable to a machine part for joint displacement therewith and arranged between the first and second bodies for movement relative to the one of the first and second bodies, which diaphragm has an area formed in such a manner than an inductive effect and an eddy current effect which result from axial oscillation of the diaphragm, upon flow of an alternating current through the coil, cancel each other with respect to their electrical action on the coil.

Abstract: A displacement measuring apparatus including a variable inductance coil formed of a pair of coils, on a core of predetermined length made of a material having high magnetic permeability. The pair of coils are disposed on a core adjacent to each other in their axial directions and are covered by a metal sleeve of substantially the same length of one of the coils. A detecting circuit is provided including a high frequency oscillator and a rectifier and is connected to the variable inductance coil, wherein when the metal sleeve is slidably moved, the detecting circuit generates a direct current voltage in correspondence with the displacement of the metal sleeve.

Abstract: The transducer comprises only a simple coil in which a core normally connected to a device the position of which is to be measured is displaced axially. The core comprises a rod of ferromagnetic material surrounded by a tube of good electrical conductivity but of small magnetic permeability. The coil is supplied by an alternating current producing eddy currents in the tube. The drop of sensitivity due to the increase of the resistivity of the tube with the increase of the temperature is compensated by the increase of the sensitivity due to the increase of the permeability of the rod with the increase of the temperature. The transducer is of light weight and of small dimensions and it is compensated in temperature in the temperature range comprised between -40.degree. C. and +20.degree. C.

Abstract: A method and system for exploiting the signals of linear inductive sensors, which system is adaptable for different sensor structures. The system is formed of a linear inductive displacement sensor provided with a primary coil and two identical symmetrical secondary coils which are in series and in antiphase. A mobile core and an alternative voltage source are mounted between the terminals of the primary coil wherein the amplitude of the voltage at the primary coil terminals is greater than the maximum amplitude of the voltage that can be taken at the secondary coil terminals. The method has the steps of forming the sum of the two alternative voltages present at the primary and secondary coils. These voltages are rectified by means of full wave rectifying and deriving the difference between the sum of recitified voltages. A continuous means valve corresponding to the difference is also derived.

Abstract: A compensation winding for improving the linearity of a displacement transducer. The displacement transducer is the type having an electrically conducting non-ferromagnetic wall which moves in telescoping relation with the coil and is excited by a signal at a sufficiently high frequency that skin effect on the wall permits displacement of the wall to vary the reluctance of the coil flux path and thereby vary its inductance proportionally to displacement of the wall. The compensation winding is wound in telescoped, coaxial relationship to the coil in a fixed position. The compensation winding has a pitch which is a decreasing function of the distance from the end of the coil which is nearest the wall when the wall and the coil are in their least overlapping relationship.

Abstract: A displacement transducer has a movable slug which varies the mutual inductance of two coil sections. The coil sections are connected in a network which causes a variation of phase shift in a signal from an oscillator on movement of the slug. A phase detector detects this phase shift. The use of a variable phase design overcomes the need for high gain linear amplification and the problem of noise in conventional variable amplitude linear variable displacement transducers. The variable phase shift network obviates the need for balanced amplitude quadrature input signals of one known variable phase transducer, while giving a linear phase shift wihtout the need for a specially shaped slug as in another known variable phase transducer.

Abstract: For enabling a resolver to have absolute position sensing over a wide displacement range while still obtaining the resolution, accuracy and precision obtainable by operation in an incremental mode, the resolver is provided with a number of terminals for providing offset pitch phase indications as a function of position. A microcomputer is programmed to execute a decoding procedure for reading the offset pitch phase indications and from them computing the absolute position. This method is applicable to linear as well as rotary position sensing. By using multiplexing, digital signal processing and large-scale circuit integration of interfacing the resolver to the microcomputer, the method can achieve absolute position sensing with high reliability and low cost. The offset pitch phase indications are readily provided by inductive coupling between a multiplicity of windings, including a set of offset pitch windings connected to the terminals.

Abstract: A linear resolver utilizes multiple pairs of nulled coil sets arranged co-linearly for sensing the position of multiple edges of a magnetically permeable object. An excitation coil produces an alternating magnetic field which is normally weakly coupled to the nulled coil sets across a magnetic gap. As the object covers the area of the gap, the coupling between the excitation and the individual coils in a nulled coil set is increased. Each nulled coil set produces an output which varies cyclically with increasing coverage of the object. The two nulled coil sets in each pair of nulled coil sets are offset from each other so that their cyclical outputs are offset by one quarter cycle, or 90.degree. with respect to the area of coverage by the object. Detection means are provided which resolve the outputs from a pair of nulled coil sets to precisely determine the position of the object edge. Each nulled coil pair is processed separately by the detection means so that multiple edges can be detected.