Abstract: A device for measuring the position of a target includes a track, which includes a primary winding (513) supplied with an alternating current at high frequency, and a plurality of secondary windings (511, 512). The device measures the position of the leading edge (510) of the target (500) in a so-called longitudinal direction (5000) between a first position and a second position between which the target (500) completely covers the track (550). Surprisingly, this configuration enables a very significant increase in the useful measurement length of such a track (550).

Abstract: The invention relates to a rotary transmitter for example for use in machine tools with adjusting tools. The rotary transmitter comprises a stator part (18) and a rotor part (26), each having a respective stator core part (72) and a rotor core part (74), which are separated from one another at mutually facing ends via an air gap, and each having at least one respective power winding (76, 78), which is wound on the stator core part and the rotor core part, in order to transmit power using the transformer principle, and having respective stator and rotor coupling turns (80?, 80?, 82?, 82?), which are associated with one another in pairs, for inductive data transmission. One aim of the invention is to transmit data without interference. A further aim is a low maintenance requirement.

Abstract: A device for measuring the position of a first body relative to a second body comprising: a first body which further comprises an electrical intermediate device; a second body which further comprises at least two inductors energised with an alternating current and at least one of which is formed by a planar spiral winding on a printed circuit board normal to the measurement axis and attached to the second body; arranged such that displacement of the electrical intermediate device causes a change in inductance of the planar spiral winding and whereby measurement of the ratio of the inductances indicates the position of the first body relative to the second.

Abstract: A method of extending the life of an extruder screw by affixing tiles of wear-resistant material along the crest of the extruder screw flighting threads, and optionally grinding the hardened material to remove any sharp edges. In another configuration of the present invention, plates of wear-resistant material are secured to the leading edges of the extruder screw threads to further prolong the life of the extruder screw.

Abstract: A rotary variable differential transformer apparatus for determining angular position of a rotor includes a stator support structure, a first pair of magnetically permeable stator elements and a second pair of magnetically permeable stator elements. The first and second pairs of stator elements are connected via first and second connecting members, respectively and are substantially supported by the stator support structure. Circuitry for generating a position indicator signal, including an array of coils is coupled to the first and second pairs of stator elements. A rotor is mounted within the stator support structure and substantially surrounded by the first and second pairs of stator elements. The rotor has a magnetic flux conducting element mounted thereon, which couples each of the first and second pairs of magnetically permeable stator elements in a manner which varies in proportion to the angular position of the rotor.

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: The present invention concerns the domain of inductive contactless sensors, allowing the position and/or the movement of a target sensitive to a magnetic field to be detected. The invention provides a miniature sensor comprising at least a primary coil generating an alternating magnetic field and at least two secondary coils for picked up such field, the coils being planar. The amplitude of the signal picked up by each coil is when the target passes in front of the coils, so that by measuring the signal amplitude or phase modulation, the speed and the direction of movement, or position of the object to be detected, is detected.

Abstract: A high efficiency radio frequency (RF) impedance matching network containing an "L-type" inductor-capacitor (LC) circuit where the capacitor is a variable capacitor coupled from an input port to ground and the inductor is a variable inductance inductor coupled from the input port to an output port. A blocking capacitor is provided between the inductor and the output port and a ceramic capacitor is coupled in parallel across the variable capacitor. The impedance match is tuned by physically adjusting tuning elements of both the inductor and capacitor. The variable inductor contains an improved inductor tuning element that optimizes current flow in the tuning elements and inductor. To further improve the efficiency of the matching network, the assembly uses an improved enclosure interior finish and various circuit optimization techniques that reduce contributions to match loop resistance.

Abstract: An angular displacement sensor for limited angle applications (e.g., for sensing automotive throttle positions) comprising first (14) and second (16) relatively rotatable components arranged to confront each other axially. The first component (14) provides a plurality of poles (14A, B, C) which are angularly disposed about the rotation axis and extend towards the second component. These poles (14A, B, C) have axes which extend in the same direction as the rotation axis. Some poles have windings (14A, B), while others (14B) provide flux return paths. The second component comprises an inductance affecting component (16) which overlies only some of the wound poles at any given time, the relative rotation varying the poles which are overlaid. The sensor includes an output unit (17) for providing output signal data related to the inductances of the excitation poles and thus related to the rotary configuration of the components.

Abstract: A measuring device for contactless determination of a rotary angle has two movable members which are rotatable relative to one another and two sensor coils whose resistance value to alternating current is varied by relative changes of values of regions of the members associated with the coils. One of the bodies members has a region corresponding to a number of the coils. At least one of the coils formed as a wire coil is arranged on the region. At least one second of the members is arranged on both end sides of the first member.

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: In a screened inductance sensor having a drive winding, a sense winding, and a conductive screen for varying the induced voltage in the sense winding by reason of the eddy currents generated in the conductive screen in the presence of the drive field, a physical barrier is interposed between the region of the sensor in the windings are located and the region in which the screen is located. These regions are fully environmentally isolated from each other by the physical barrier. The construction is especially suited to screened inductance level gauges, in particular for fuel tanks, where the conductive screen is part of a float assembly in contact with the fuel, but the electrical windings are kept dry in a separate portion of the gauge.

Abstract: A transducer measures the angular relationship between a drive and a driven member throughout a range of relative angular positions therebetween. The transducer provides a signal indicative of that angular relationship, and the signal can be transmitted to a controller that regulates the torque applied by the drive shaft. The transducer can be used in a web spooling apparatus where the position of the driven member relative to the drive shaft during web winding operation is a function of tension transients in the web. The transducer enables the system to adjust the torque of the drive shaft as a function of the angular relationship of the driven member and drive shaft so that the system can reduce tension transients in the web being wound onto the spool.

Abstract: Various forms of hydraulic cylinders having axial bores formed in their piston rods, and probes projecting axially from the closed end of the cylinder body with two spaced coils thereon are disclosed. The coils are connected into external circuitry which responds to change in inductance of either coil whereby to generate a reference signal upon the occurrence of preselected changing conditions of inductance of either coil caused by movement of that coil into or out of mutual induction with a shorted turn arrangement formed by or carried by the piston. The coils may be the drive coils of a displacement transducer arranged to indicate either end of the stroke of the piston. Alternatively either a supplementary shorted turn or an additional drive coil may be provided to generate an intermediate stroke reference signal. The reference signals may be used in operation of a system for effecting automatic continuous reciprocation of the piston.

Abstract: A musical keyboard having keys which carry metal spoilers that alter the resonance characteristics of tank circuits associated with the keys as the keys move toward and away from the inductance coils of the tank circuits. The tank circuits are connected sequentially to a frequency sensing circuit which develops indications of key positions by sensing the resonance frequency of each tank circuit.

Abstract: In a screened inductance sensor system having a drive winding energizable to set up an alternating magnetic drive field, a sense winding links the drive field and a screening element modulates the spatial distribution of the drive field, when in the vicinity of the sense winding. Variations in voltage induced in the sense winding provide an indication of the relative position of the screening element and the sense winding. The drive winding and the sense winding are accommodated in a displaceable portion of the sensor, and the screening element is fixedly located relative to the movable sensor portion. Modulation of the spatial distribution of the drive field occurs when the displaceable sensor portion is moved into the vicinity of the screening element.

Abstract: Two-phase voltage signals for use with a resolver-to-digital converter (RDC) are produced as a periodic function of permeance developed across an air gap between a rotor and stator wherein the permeance varies as a periodic sinusoidal function which can be related to the electrical angle of the position of the rotor. The two-phase voltage signals are developed as a function of inductive reactance and follow the form ##EQU1## wherein the phase angle between V.sub.x and V.sub.y is exactly 90.degree. and the term [A+A.sub.n +B+B.sub.n ] is completely free of second harmonics.

Abstract: An inductance coil sensor in which a rotating spoiler (46) alters the inductance of a stationary coil (1230/1432) having two parts (12a, 12b; 30a, 30b/14a, 14b; 32a, 32b) disposed on opposite sides of the spoiler. Changes in inductance of the stationary coil are sensed to develop an indication of the rotary movement of the spoiler which, in turn, represents changes in the parameter being monitored. By locating one part of the stationary coil above the spoiler and one part below the spoiler, compensation is provided for undesired movements of the spoiler along its rotation axis.

Abstract: In a sensor having a drive winding for establishing a forward field, an electrically conductive screen is displaceable relative to a sense winding. In the presence of the drive field, eddy currents are generated in the screen to establish a counter-field opposing the forward field, so that the sense winding is shaded by the screen to a varying extent during relative displacement of screen and sense winding and the voltage induced in the sense winding is accordingly correspondingly varied. Application of a high frequency input to the drive winding results in a modulated output from the sense winding which may be demodulated to provide a signal indicative of screen position relative to sense winding. The position signal may be further processed to provide a speed signal. The sensor may assume a multiplicity of linear or planar, rotational and axial or solenoidal configurations.

Abstract: A series of rotary sensors are disclosed. Each sensor consists of a drive coil which is a planar coil configuration separated from a sensing coil which is parallel to the drive coil. Interposed between the drive and sensing coils is a rotatable plate fabricated from a material capable of blocking a magnetic field induced in a drive coil from reaching or activating the sensing coil. The rotatable plate is shaped to allow predetermined amounts of flux to couple from the drive coil to the sensing coil as the plate is rotated. The shape of the plate therefore determines the signal provided at the sensing coil to enable one to provide such signals indicative of the angular movement of the plate between wide limits as from zero to 360.degree.. Other configurations utilizing a plurality of drive and sense coils and special shaped plates provide sine and cosine outputs as well as enable one to determine the quadrant of operation.

Abstract: A planar coil apparatus is disclosed for providing an output signal indicative of a movement between at least a first and a second position. A first stationary planar member has disposed on a surface, a first flat coil configuration which is emplaced thereon by a printed circuit or similar technique. Located adjacent to this coil on the board is a second coil of similar configuration. A drive signal such as that obtained from an AC or pulse source is applied to the input terminals of one of the coils which constitutes the drive coil. A second planar board is positioned relatively congruent and above the first board and has located thereon a closed coil configuration which constitutes a closed coil loop. As this movable board is brought into proximity with the stationary board, magnetic flux is coupled via the loop from the drive coil to the second coil which serves as the sense coil.

Abstract: The variable inductor and the comparison inductor of a semi-differential variable inductance both have a pair of coils magnetically coupled together. The output current of an amplitude-controlled oscillator flows through the series combination of one coil of each pair and the other coil of the comparison inductor is used to supply a signal which is rectified in order to regulate the amplitude of the oscillator. The remaining coil, the other coil of the variable inductor, is rectified to provide an output signal representative of the ratio of the variable inductance to the comparison inductance and also representative of the displacement of the short-circuiting ring of the variable inductance, which is mechanically linked to the control rod of a fuel injector of a diesel engine as required for a system controlling the fuel injector. The oscillator and the rectifiers can conveniently use operational amplifiers of the same type designation.

Abstract: An apparatus for applying tabs to end units wherein the tabs are in the form of an aluminum foil-plastic film laminate. A heating dial is provided for receiving tabs, rotating the tabs by indexing, and then applying the tabs. The heating dial includes a radio frequency transformer which includes a fixed primary winding and a segmented secondary winding which is rotatable as a unit together with heating elements secured thereto. The secondary winding segments are circumferentially spaced and each heating element is secured to two adjacent segments in bridging relation.

Abstract: An adjustable output transformer using a pair of adjacent facing pot cores, the first of which carries both primary and secondary windings, the second having only a shorted winding around one leg. The shorted winding inhibits flux through its leg and the corresponding portion of the adjacent leg on the first core so that the secondary voltage may be varied by adjusting the relative rotational positions of the two cores and hence the amount of flux linking the secondary winding.

Abstract: A core with at least three elongated legs, at least one leg being centrally located among all the elongated legs, is joined at at least one end by a yoke portion connecting all the legs. The central leg or legs is wound with a magnet winding close to the yoke portion of the core, with which the core is excited with an alternating field. A short-circuiting ring structure, which may be in the form of an apertured plate, encircles at least the central leg or legs of the core and is movable in the direction of elongation of the core in accordance with the movement of a body the displacement of which is to be measured. The legs of the core may be bent in order to measure rotational or angular displacement. Movement of the short-circuiting ring along the length of the core varies the inductance of the coil in a predetermined manner, which may be a linear relation to displacement. A yoke and a winding may be provided at the other end in order to increase the sensitivity by a differential method of measurement.

Abstract: An induction-type meter for measuring mechanical quantities, comprising a first converter to convert the controlled parameter into a displacement and having elements adapted to be moved relative to each other, and a second converter to convert the displacement into an electric signal and including a magnetic circuit with a block of coils mounted on one of the elements capable of relative movement, and a diamagnetic screen mounted on the other element capable of relative movement. The magnetic circuit is embodied as a closed-open loop system comprised of two parallel parts formed by armored cores mounting said coils and arranged to provide a gap accommodating said diamagnetic screen with profiled working edges.

Abstract: An inductive transducer is provided with a core with legs extending in opposite directions from a yoke on which a coil is wound. On the leg portions extending on one side of the coil a short-circuiting ring displaceable in accordance with the displacement of a body the movement of which is to be measured is provided and on the leg portions extending on the other side of the coil a compensating short-circuiting ring is provided having a mass corresponding to the total mass of the first short-circuiting ring and the movable portion of the body to which it is connected and the connection therebetween. The effect of acceleration forces produces an equal shift of both short-circuiting rings in the same direction, leaving the total flux linking the coil substantially unchanged. The device can be adapted to measure either linear or angular movement.

Abstract: A variable inductor having a U-shaped magnetic core with a short-circuiting plate providing a short-circuiting ring for both legs of the core movable along the core legs in response to a displacement to be measured is connected in an electronic circuit to generate oscillation of a frequency that is either directly or inversely proportional to the displacement. For the inversely proportional case, the variable inductance component can be combined with an integrator function and connected to an operational amplifier, for generation of the output frequency with a small number of electrical components. The thickness and spacing of the core legs are varied along their length to produce a highly linear inductive transducer characteristic. The core legs are bent in a circle when it is desired to measure an angular displacement.

Abstract: The inductance of a coil wound on one end of an elongated rectangular core with an elongated central window is caused to vary by the displacement of a conducting plate or ring arrangement lengthwise of the core. The other end of the core may also be wound with a coil to produce a differential type of transducer. The elongated core may be bent around into a circle in order to provide a transducer for rotational displacement. Additional ferromagnetic bodies in fixed relation to the core or to the short-circuiting rings can be used to modify the translation characteristic.

Abstract: The inductance of a coil wound on one end of an elongated rectangular core with an elongated central window is caused to vary by the displacement of a conducting plate or ring arrangement lengthwise of the core. The other end of the core may also be wound with a coil to produce a differential type of transducer. The elongated core may be bent around into a circle in order to provide a transducer for rotational displacement. Additional ferromagnetic bodies in fixed relation to the core or to the short-circuiting rings can be used to modify the translation characteristic.

Abstract: An improved servomechanism control cylinder has a housing and a position feedback system contained in the housing. Movement of a piston of the control cylinder moves a shield relative to a fixed electrical coil for changing the signal delivered by the position feedback system. The delivered signal is representative of the position of the piston and can be utilized for controlling movement of the piston.

Abstract: A pulse producing device has an E-shaped core with an input winding and an output winding, so that flow of flux between the limbs of the core produces an output in the windings. The flow of flux is controlled by parts rotating close to the limbs, and these parts are formed on a rotatable plate the periphery of which is split and deformed to provide two rows of tags, one row passing close to the central limb and one of the outer limbs and the other row passing close to the central limb and the other outer limb.