Abstract: A timing apparatus comprises a gear, for example a camshaft gear, and a timing ring secured to one side of the gear. The timing ring has a number of equally spaced timing teeth which when used with a sensor provide information about the rotation of the gear. The gear has a generally cylindrical recess on one face of the gear, and the timing ring is secured within the recess. The timing teeth are arranged radially inwardly of the gear teeth, so that the timing teeth are protected from damage. The resulting timing apparatus is economic to manufacture and facilitates compact adaption to a rotating body of an engine.

Abstract: A multi-turn rotary encoder that includes a first code carrier connected with an input shaft, a scanning device that scans the first code carrier and generates an absolute position of the input shaft within one revolution, and a digital code word is present at an output of the scanning device and a second code carrier for measuring the number of revolutions of the input shaft. A reduction gear is arranged between and coupled to the first and second code carriers. The second code carrier includes a magnetic body with at least one north and south pole and a substrate with a spatial arrangement of sensor elements integrated therein, which are sensitive to magnetic fields, is associated with the magnetic body.

Abstract: The seat position sensor includes a housing, a magnetoelectric converting element which performs changeover of an output at a given magnetic field intensity, and a magnet which is held by the housing at a position where the magnet faces the magnetoelectric converting element in an opposed manner. A shielding plate is capable of entering into or exiting from a space defined between the magnetoelectric converting element and the magnet. An inverse bias magnet which applies a magnetic field of an inverse direction to the magnet is provided to a side opposite to the magnet side while sandwiching the magnetoelectric converting element therebetween.

Abstract: A capacitive motion encoder, for sensing the position of a moving object relative to a stationary object, includes at least one stationary element, coupled to the stationary object and a moving element, coupled to the moving object and in proximity to the stationary element. A field transmitter generates an electrostatic field, which is modulated by a change in capacitance between the stationary and moving elements responsive to relative motion of the elements. A conductive shield, is electrically decoupled from both the moving and the stationary objects, and encloses the moving and stationary elements so as to shield the elements from external electrical interference. Processing circuitry is coupled to sense the modulated electrostatic field and to determine responsive thereto a measure of the position of the moving object.

Abstract: A magnetic incremental encoder includes a plurality of detection devices which are provided on an outer periphery of a rotational member at a predetermined phase difference, wherein each of the detection devices outputs signals which vary periodically in accordance with the rotational angle of the rotational member upon rotation thereof; wherein the plurality of detection devices are provided in sets of two detection devices on the outer periphery of the rotational member, wherein a phase difference between one of the sets of two detection devices and an adjacent another of the sets of two detection devices is determined according to the following formula: 2&pgr;P+&pgr;/j; wherein P designates an arbitrary integer; and j designates one of the number of k orders, wherein k designates the number of orders of harmonic distortions to be corrected. The number of the plurality of detection devices is equal to 2k.

Abstract: A position detector is provided for detecting the relative movement of first and second members which are mounted for relative movement along a measuring path. One of the members comprises a magnetic field generator for generating a magnetic field and the other member comprises first and second conductors which are inductively coupled to said magnetic field generator. The arrangement of the first and second conductors and the magnetic field generator is such that output signals are generated in a first and second receive circuits whose position varies with the relative movement between the two members. In addition to carrying information relating to the relative position between the two members, the signals induced in the receive circuits also comprise information defining the relative orientation of the two movable members, and by suitable processing of the received signals the relative orientation of the two members can also be determined.

Abstract: A magnetic encoder includes a magnetic drum having, on the outer peripheral surface thereof, magnetized portions spaced at equal pitches; a magnetic sensor unit opposed to the outer peripheral surface of the magnetic drum; magnetic sensors are provided in the magnetic sensor unit spaced at a distance smaller than one pitch of the magnetized portions; a calculation device for calculating two sets of vectorial signals, from detection-signal output levels of the magnetic sensors generated upon rotation of the magnetic drum or the magnetic sensor unit, using the following equations (1) and (2):

Abstract: A magnetic incremental motion detection system for outputting a plurality of voltage and/or current signals in analog or digital form wherein the voltage and/or current signals are a collective representation of any incremental rotational, linear, or pivotal movement of an object. A target of the system is adjoined to an object to synchronously move with the object. A plurality of indications are adjoined to the target, and uniformly and serially disposed along an area of a surface of the target. The system further comprises one or more magnetic sensors spatially positioned from the area of the surface to define air gap areas therebetween. Each of the magnetic sensors are operable to output at least one analog signal in response to a synchronous movement of the target with the object. The outputted analog signals have the same duty cycle, and are consistently out of phase with each other by the same degree.

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 absolute-value encoder device for detecting a plurality of rotation quantities is disclosed. An A/B phase forming portion 610 forms an A-phase pulse signal and a B-phase pulse signal, based on light passing through a slit rotating together with a rotary shaft. One period of each of those pulse signals corresponds to one revolution of a rotary shaft. The A- and B-phase pulse signals are displaced in phase by 90° from each other. When an A/B-phase state detecting portion 640 detects a state change of each of those pulse signals, a clock forming portion 66 changes a frequency of a clock pulse signal to another frequency.

Abstract: This invention relates to a steering angle sensor wherein the angle values are determined by the position of a code disk provided with an incremental track and a code track. So as to be able to express the 8-step-code-word-defined precision by means of six-step code words on the code track the six-step code words are supplemented by 2 bit resulting from the momentary state of the incremental track scanned by two detectors.

Abstract: The invention provides a method of sampling precision measurement signals to achieve an accurate measurement position at a particular measurement time, such that the measurement accuracy is unaffected by the velocity of motion. The method involves sampling each signal during a predetermined sampling period such that a signal from one sensor is sampled first, a signal from a second sensor sampled second, etc., and then the signals are sampled in reverse order such that the first signal sampled is sampled last. These sampled signals are averaged and produce a precision measurement at a time measured at one-half of the sampling time. In addition, this method can be applied to the use of separate scale tracks where each scale track is alternately sampled, or alternatively, where one scale track is sampled in the middle of the sampling period of another scale track.

Abstract: A linear position encoder is provided which is not affected by ambient light, smoke, moisture, particulate matter, and also not affected by electrical interference such as may be caused by stray fields or permanent magnets or magnetic particles. The encoder comprises a linear scale having an excitation loop disposed along the length of the scale and having electrical terminals preferably disposed at one end of the scale. An alternating current is applied to the excitation loop to create an alternating magnetic field. At least one periodic conductive pattern is provided on an outer side of the excitation loop. The periodic pattern has electrical terminals preferably at the same end of the scale as the terminals of the excitation loop. A sensor is provided on a small printed circuit card that is movable in relation to the scale. The card has a pickup loop which receives energy coupled from the scale excitation loop and which induces current in the periodic pattern.

Abstract: A moving target opposite a stationary analog sensor has two sensitive elements delivering two sinusoidal output signals, of equal maximum amplitudes, centered on the same average value, in quadrature and with a period equal to one revolution of the target. A device for processing the two output signals, generates n output signals in-parallel, where n is a positive whole number greater than or equal to 2, for providing the position of a rotating component, connected to the moving target, with a resolution equal to 2n. The processing device includes a generator device, a detection device, a multiplexing device and an interpolation device.

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: A detector of position of rotation of a target wheel via the outputs of a differential sensor employing two matched MRs to extract position of rotation information from the target wheel. The target wheel is provided with wide and narrow slots or teeth circumferentially arranged such that, for example, 24 zones are created wherein each zone ranges from the center of a wide slot to the center of a narrow slot, and wherein each zone occupies 15 degrees circumferentially. The two matched MRs of the sensor are powered by matched current sources and matched magnetic biasing and are aligned in the circumferential direction of the target wheel. The MRs generate two angularly offset signals from the passage of a single slot (or tooth) of the target wheel which are input to a signal conditioning circuit. Within the signal conditioning circuit, the two sensor signals are differentially amplified to produce a differential signal whereby the width of the slot is used to encode a binary position pulse.

Abstract: A position detector is provided for detecting the relative movement of first and second members which are mounted for relative movement along a measuring path. One of the members comprises a magnetic field generator for generating a magnetic field and the other member comprises first and second conductors which are inductively coupled to said magnetic field generator. The arrangement of the first and second conductors and the magnetic field generator is such that output signals are generated in a first and second receive circuits whose position varies with the relative movement between the two members. In addition to carrying information relating to the relative position between the two members, the signals induced in the receive circuits also comprise information defining the relative orientation of the two movable members, and by suitable processing of the received signals the relative orientation of the two members can also be determined.

Abstract: A method for more accurately sensing the rotational position of a shaft having a toothed sensor wheel with a missing tooth is disclosed. The method includes employing an inductive sensor to produce a signal in response to the passing of the teeth on the sensor wheel. The sensor signal is altered by the geometry of the wheel about a gap formed by the missing tooth in order to correct for residual stored energy in the sensor at this location, and thus correct the signal for the timing measured by a processor in communication with the sensor.

Abstract: A rotary transmitter for registration of the steering angle of a motor vehicle, with a transmitter component (49) on which is provided a coding (51) of a predetermined number n of locally sequentially digital words (Wi) with a width of m bits (b1, b2, . . , Bm) in m adjacent to each other tracks, at least one detector (55) for essentially simultaneous registration of the individual bits (b1, b2, . . . , Bm) of a digital word (Wi), whereby the transmitter component (49) and at least the one detector (55) are movable relative to each other, and with an evaluation unit (11) to which is conducted the signal of at least the one detector (55). The evaluation unit (11) ascertains the absolute position of the transmitter component (49) relative to at least the one detector (55), at least one time, by evaluation of a predetermined number (p) of sequentially detected digital words (Wi), whereby the evaluation unit (11) assigns to a detected p-measure (Wi, Wi+1, . . .

Abstract: A geartooth target providing a consistent magnetic signal for each feature type with unambiguously readable features has three unique 30° segments, each segment ending with a falling edge transition, the segments placed to have a unique pattern of segments every 90°.

Abstract: The device for determining a steering angle of a motor vehicle with a steering column, a steering mechanism and a steering tie rod includes a device for generating a fine signal according to an angular position of the steering wheel, a device for generating a coarse signal according to a number of revolutions through which the steering column has been turned in one or the other direction, and a device for combining the fine signal and the coarse signal to obtain the steering angle.

Abstract: A magnetic encoder apparatus comprises a moving disk 5 made of a magnetic substance including a position detection slit track 31 provided with a slit for detecting the position thereof, a magnetic pole detection slit track 33 provided with a slit for detecting the magnetic pole of a motor, and a reference detection slit track 32 provided with a slit for detecting the reference position thereof, magnetic sensors 1 being spaced out the moving disk; bias magnets 2 each provided on the back face of the respective magnetic sensors and situated at where corresponds to the respective slit tracks, and a signal processing circuit 6 for processing a signal from the magnetic sensors.

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 scale device 1 includes a base unit 2 comprised of an elongated casing 3 wherein an elongated thin-plate-like scale 4 is secured with the a mid portion of the thin-plate-like scale 4 kept in a floating state and a slider unit 10 slidable relative to the base unit 2. The slider unit 10 has a sensor 15 for detecting magnetic graduations recorded on the thin-plate-like scale 4. A reference sliding member 16 is provided for maintaining a constant separation between the sensor 15 and the recording surface of the magnetic graduations of the thin-plate-like scale 4. A pressing sliding member 17 is provided for pressing the reference sliding member 16 so that the recording surface of the magnetic graduations are perpetually contacted with the reference sliding member 16. A detection head unit 14 is movable telescopically relative to the thin-plate-like scale 4 in a direction along the width of the scale.

Abstract: A position encoder is provided for indicating the relative position between first and second relatively movable members. One of the members carries a multi-pole magnetic scale which generates a magnetic field whose magnitude and direction vary with position and the other member carries at least one sense conductor. A saturable magnetic element is located in the positionally varying magnetic field of the magnetic scale and an excitation winding is provided which, when energized, generates a magnetic filed which interacts with the positionally varying magnetic field to cause different portions of the saturable magnetic element to saturate and desaturate at different times. The arrangement of the sense conductor is such that as the magnetic element is driven into and out of saturation, it outputs a signal which is indicative of the position of the magnetic scale relative to the sense conductor.

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: Onto a long rectangular board like base board, first Hall IC's are mounted at specified equal pitches in the longitudinal direction, and second Hall IC's are mounted at the equal pitches from a position shifted by a phase difference of 90 degrees in the longitudinal direction relative to this first Hall IC, and a single rectangular board like field magnet (12) having a length of a half of the equal pitch is mounted, opposite to the first Hall IC's and the second hole IC's, and consequently, a linear encoding device is provided, by which a long positional measurement can be performed, and further, which has a simple arrangement.

Abstract: The present invention discloses an optical sensing system which uses a plurality of detectors installed at various positions next to an optical panel to generate a position signal for indicating the position of the optical panel. The optical sensing system has an optical panel having a plurality of sensing areas each having a plurality of encoding holes arranged in a predetermined direction, a sensing device having a plurality of detectors for detecting movements of the optical panel corresponding to the sensing device, each of the detectors being corresponded to one of the sensing areas of the optical panel for detecting movements of the encoding holes along the predetermined direction and generating correspondent sensing signals, and a control circuit electrically connected to the sensing device for collecting the sensing signals generated by the detectors of the sensing device to form a position signal so as to indicate the optical panel's position.

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: A device for detecting faults including sensor failure in a sensor that outputs a substantially binary output signal is described. For fault detection, the various terminals of the sensor are supplied with substantially binary voltages from a fault detection circuit and the changes in the output signal of the sensor that occur as a consequence of the supplied voltages are evaluated for fault detection.

Abstract: An apparatus is provided to determine the speed and direction of a rotating shaft, including a rotor with three circumferentially spaced teeth connected to the shaft. The spacing of the center of the second rotor tooth is wider than the spacing of the center of the first tooth and the spacing of the center of the third tooth is wider than the spacing of the center of the second tooth. A sensor detects the center of each tooth and produces a signal in response thereto. The signal is received by a computer. The computer determines the speed and direction of rotation of the shaft by determining a first time period to reach the center of the first tooth, a second time period to reach the center of the second tooth and a third time period to reach the center of the third tooth.

Abstract: An electrical signal transmitter intended for use in a motor vehicle is disclosed. The signal transmitter is provided with a magnetic sensor device for the detection of various positions of a movable vehicle part. To properly recognize a variety of positions, the movable part is connected with a correspondingly movable magnetic trigger member located on a holder. The trigger member has several magnetic tracks extending in the longitudinal direction of movement of the trigger member. Each magnetic track is provided with alternating N/S pole sections to provide a coding scheme. At least one magnetic field sensitive component is associated with each magnetic track to sense fields generated from the N/S pole sections. The at least one magnetic field sensitive component then generates a signal based on the sensed magnetic fields. The signal is indicative of the position of the magnetic trigger.

Abstract: A magnetic encoder is disclosed that provides a uniform magnetic field which is time modulated at a carrier frequency and space modulated by a repetitive pattern of eddy-current conducting lands that move with variable motion. The time modulation is provided by driving an electrical coil in a resonant tank circuit. The space modulation provides areas of higher and lower magnetic field intensity which change in correspondence with the motion of the conducting lands. The intensity of the varying magnetic field is detected by a series connected pair of stationary coils that are positioned orthogonal to both the direction of the changing magnetic field and the direction of the motion of the conducting lands. The pair of stationary coils yield a differential electrical signal that is representative of the motion of the conducting lands.

Abstract: An angular position sensor is provided by disposing two sensors proximate a rotatable member. A stationary sensor is located in a fixed position and a movable sensor is pivotable about the center of rotation of the rotatable member. A software routine uses a first output signal from the stationary sensor to calculate the rotational speed of the rotatable member. The software also determines a time offset between the receipt of a signal pattern by the stationary sensor and a subsequent receipt of the same pattern by the movable sensor. Using this time offset and the rotational speed of the rotatable member, the angular difference between the positions of the movable and stationary sensors can be developed. This angular difference is equivalent to the throttle position.

Abstract: A sensing method continuously scans an array of sensing elements and determines positions by converting array peak amplitude information to a time based function. An array of magneto resistive elements responds to a relatively moving magnetic field. The process of scanning the magneto resistive elements is independent of the relatively moving magnetic field. Instead of using only one voltage source to power both the driving logic circuitry and the sensing element array, a separate voltage source for powering the sensing element array is used in conjunction with the solid switch array, thus excluding unwanted noise that originates in the driving logic circuitry.

Abstract: A rotatable rotor 41 and a stator 51 located at a predetermined gap between outer circumferential face of the rotor 41 provided with half-cylindrical inner circumferential face are provided. The both ends of the outer circumferential face of the rotor 41 are provided with a step portion 44 to retain a predetermined gap between the opposing faces of the rotor 41 and the stator 51, and a stopper portion 45 to be abutted to both end faces of the stator in the axial direction. A forcing means 61(plate spring) are also provided to force the stator 51 to the rotor 41 so that the inner circumferential face of the stator is abutted at the step portion 44.

Abstract: Magnetic poles are regularly spaced along a path to form a magnetic track. Some of the magnetic poles are separated by regular pole junctions aligned uniformly with respect to the path of the magnetic track. At least two of the magnetic poles are separated by a skewed irregular pole junction aligned such that a sensor near an edge of the magnetic track will sense a wide pole and a narrow pole to allow an index signal to be produced.

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 sensing device for determination of a steering wheel angle of a steering column of a vehicle includes a first coded disk which is read by a first group of receiving devices to form a fine code signal and which rotates at the same speed as the steering wheel. A second coded disk rotates with a fourth the speed of the first disk and has two or more pole change positions which are detected by a second group of receiving devices to form a gross code signal. Hall elements are used as receiving devices. Magnetically coded disks having a predetermined sequence of alternating North and South pole regions are used as the coded disks. These regions are distributed around the periphery of the disk and have different arc lengths. Hall switching devices are used as receivers which cooperate with the magnetic regions of the coded disks.

Abstract: A position encoder system is provided, such system including a code wheel, a pair of sensors, a counter, and a processor capable of identifying the correlation between separately identified markings of the code wheel. The identified correlation is indicative of code wheel accuracy, and thus is used to correct error in any angular position determined using the code wheel.

Abstract: A rotation sensor includes a binary encoded target wheel and a pair of sensors disposed about the target wheel periphery. One of the sensors provides a signal indicative of the passage of regular angular intervals of the target wheel and the other of the sensors provides binary states corresponding to the regular angular intervals.

Abstract: An encoder for measuring a relative position between two objects and including a scale support connected with one of the objects, and a scanning unit displaceable along the scale support and connected with the other of the two objects, either directly or by a carrier, by a coupling having a first coupling part attached to the scanning unit, a second coupling part attached to the other object and a carrier, and a third ball-shaped coupling part located between the facing each other surfaces of the two coupling parts and held in a constant contact with these facing surfaces by magnetic forces.

Abstract: A pointing device includes a plate which is made of a magnetic material and having at least one surface with a regular change in first geometrical configuration along a direction y and a regular change in second geometrical configuration along a direction x which is perpendicular to the direction y, where the change in first geometrical configuration is different from the change in second geometrical configuration, and a coordinate input part slidably provided on the surface of the plate. The coordinate input part comprises a mechanism for generating one of a magnetic flux and magnetic field, and a mechanism for detecting a change in the magnetic flux or magnetic field fed back to the coordinate input part via the plate and generating signals indicating a moving direction and a moving quantity of the coordinate input part on the plate.

Abstract: A rotary encoder 10 is composed of a halfway cylindrical stator 11 and a cylindrical rotor 12. The rotor 12 is disposed coaxial with the stator 11 with a predetermined gap. Plural transmitting electrodes 13 with spiral patterns and receiving electrode 14 with a rectangular pattern are formed on the inner surface of the stator 12. The transmitting electrodes 13 and receiving electrode 14 are formed of a FPC substrate 17 with lead lines 15, 16. On the outer surface of the rotor 12, coupling electrode 18 are formed with a spiral pattern so as to be capacitively coupled to the transmitting electrodes 13 and receiving electrode 14. FIG.

Abstract: A sensor coil pattern used in combination with a coordinate input apparatus is provided, which is adapted to exactly detecting positions if a noise source such as an converter or an electrically closed conductor exists in the periphery of the apparatus. The apparatus is provided with a sensor surface having a sensor coil pattern of many sensor coils arranged thereon in parallel with each other in position detecting directions, a position indicator, a coil or a resonance circuit incorporated therein and a switching means so connected as to select simultaneously one of a plurality of a sensor coils, wherein said many sensor coils include a predetermined number of sensor coils individually connected to the switching means, said predetermined number of sensor coils including at least one or a plurality of sensor coils counted from one end of the arrangement.

Abstract: The apparatus for determination of absolute angular position of a steering wheel (w) rotatable through several revolutions includes a fine code disk(2) nonrotatably attached to the steering column (c) and provided with circumferentially distributed code elements (2',2", 2'", . . . ) and circumferentially distributed code element sensors (5) for sensing the code elements (2", 2", 2"', . . . ) to generate fine signals which repeat after each revolution of the steering wheel and are indicative of a relative steering wheel angular position during each revolution; and a coarse code disk (7) provided with at least three code tracks (A,B,C, . . . ) and at least three code track sensors (8a, 8b, 8c , . . . ) for sensing respective code tracks (A,B,C, . . . ) to generate a progressive 3-bit coded signal indicative of the absolute steering wheel angular position over the several revolutions.

Abstract: For detecting the angle of rotation of a shaft, in particular of a gear shift shaft in a gear change box for a motor vehicle, a device is proposed in which a carrier arrangement carries a magnet and in its proximity magnetically sensitive sensors. A screening device, rigidly attached to the shaft, moves in the intermediate space between the magnet and the sensors. This screening device is made from a ferromagnetic material such that the magnetic field permeating the sensors is influenced in a manner whereby the sensors generate a signal that unambiguously identifies the position of the shaft.

Abstract: Displacement measuring apparatus for measuring the displacement and movement of an object includes a sensor having an operative surface and circuitry for producing an electrical output signal whose value is dependent upon the area of the operative surface covered by an electrical/magnetic field producing member. The apparatus also includes an elongate, flexible band capable of producing an electric/magnetic field, where the band is attached at one end to the sensor to roll over and cover or unroll from over and uncover the operative surface as the object whose displacement is to be measured is moved. The value of the electrical output signal produced by the circuitry is thus dependent upon the area of the operative surface covered by the band and thus by the position and movement of the object.

Abstract: The present invention relates to a linear encoder that does not require the connection cable to be pulled around and has a simple constitution, while also contributing to smooth operation of the moving side as well as reduced size of the apparatus. In addition, the present invention also relates to a guide wherein a guiding device composed of a track rail and so forth is added to the linear encoder. In addition to arranging a plurality of detecting elements composed of electromagnetic conversion elements and so forth at prescribed intervals along the direction of relative motion on the stationary side, a detected element composed of a permanent magnet is arranged so as to oppose the above-mentioned detecting elements on the moving side, thus obtaining the above-mentioned effects.

Abstract: A rotatable member is positioned coaxial with a joint between a first element and a second element. The joint defines an angle to be measured. The rotatable member has coded information thereon. First and second sensing heads are attached to respective elements. Coded information is arranged on the rotatable member so as to periodically pass in readable proximity to the sensing heads once every revolution of the rotatable member. A decoding system is provided for each sensing head. Each decoding system includes threshold circuitry, a state machine, and a pulse generator for providing a timing strobe. A first timer uses a timing strobe from the first sensing head for continuously determining the average elapsed time for one complete revolution of the rotatable member. A second timer uses timing strobes from the first and second sensing heads to continuously determine the average elapsed time for the coded information on the rotatable member to travel from the first sensing head to the second head.