Magnetic Patents (Class 33/708)
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Patent number: 6145214Abstract: The present invention provides a position detection apparatus capable of suppressing a crosstalk between a scale signal and an origin signal and detecting a position with a high accuracy. A recording medium 12 of a round bar shape has a magnetic signal alternately reversing the polarity at a predetermined recording wavelength .lambda..sub.1 and recorded as a scale signal in the longitudinal direction of the recording medium 12. This scale signal is recorded over the entire outer circumferential surface of the recording medium 12 and almost over the entire length of the recording medium 12. Moreover, the recording medium 12 has a one-wavelength origin signal of recording wavelength .lambda..sub.2 recorded at least at one position over the scale signal. The recording wavelength .lambda..sub.2 of this origin signal is longer than the recording wavelength .lambda..sub.1 of the scale signal. The origin signal is recorded at a part of the outer circumference.Type: GrantFiled: March 23, 1999Date of Patent: November 14, 2000Assignee: Sony Precision Technology Inc.Inventors: Tadahiko Shimano, Takamoto Yoshioka
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Patent number: 6119357Abstract: 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.Type: GrantFiled: May 19, 1998Date of Patent: September 19, 2000Assignee: Sony Precision Technology, Inc.Inventors: Osamu Ochiai, Ken Onoe
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Patent number: 6114820Abstract: A power window apparatus is provided for detecting pinching in accordance with the opened/closed position of the window and a state of rotation of a motor, the apparatus having a position sensor which detects a safety-control suspension region of the window and which is an accurate sensor. A spiral guide groove is formed in the inner surface of a housing opposite to a rotational plate which is rotated by an output shaft of a motor which opens/closes a window. A follower which is guided by the spiral guide groove is able to move along a straight guide groove provided for the rotational plate in the radial direction. Terminals in the form of conductive films are provided for a printed circuit board accommodated in the housing. When the rotational plate has been rotated, the follower is guided by the spiral guide groove so as to be moved in the straight guide groove. Thus, a slide member provided for the follower is brought into contact with the terminals so that the terminals are conducted with each other.Type: GrantFiled: March 15, 1999Date of Patent: September 5, 2000Assignee: Koito Manufacturing Co., Ltd.Inventor: Masanori Nishigaya
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Patent number: 6079113Abstract: An electronic radius gauge including a base with an inverted U-shaped configuration having a horizontal top post, a pair of side posts each coupled to opposite ends of the top post and depending therefrom, and a vertically oriented bore centrally formed in the top post. The base adapted to be removably situated on a curvature with an associated radius wherein both side posts rest thereagainst. Also included is a control housing with a probe comprising a rod. The rod is adapted to be slidably insertable through the bore and further abut the curvature. A distance measuring mechanism is situated within the control housing and is adapted to calculate a distance the post has slid up or down with respect to an equilibrium position. A display is situated on a front face of the control housing for depicting a plurality of numbers. Finally, a control mechanism is situated within the control housing and connected to the distance measuring mechanism, the display, and a power source.Type: GrantFiled: March 18, 1998Date of Patent: June 27, 2000Inventor: Terry L. Helmrichs
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Patent number: 6070337Abstract: A passive magnetic position sensor, has a substrate with a resistance network arranged on it, and a contact structure which is associated with the resistance network and which can be deflected under the action of a magnet device. An electric connection which is dependent on the position of the magnet device is produced between resistance network and contact structure. In order to provide a position sensor which has a high resolution, operates with a little wear, and is constructively simple to produce, the contact structure is developed as contact-spring structure, and the junction points of the resistance network are connected to contact surfaces also applied on the substrate. The contact-spring structure is arranged at a constant distance from the contact surfaces, the latter entering into contact with the contact-spring structure under the action of the magnet device.Type: GrantFiled: October 8, 1997Date of Patent: June 6, 2000Assignee: VDO Adolf Schindling AGInventor: Werner Wallrafen
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Patent number: 6056218Abstract: A fishing reel includes: a spool rotatably supported to a reel main body; rotation number detect element detecting the rotation number and rotation direction of the spool; a microcomputer measuring the length of a fishing line in accordance with the detected rotation number and displaying the measured fishing line length on a display device; and control element controlling the processing operation speed of the microcomputer according to a rotation state of the spool detected by the rotation number detect element.Type: GrantFiled: November 25, 1998Date of Patent: May 2, 2000Assignee: Daiwa Seiko, Inc.Inventor: Kazuya Nanbu
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Patent number: 6051971Abstract: An opto-electronic scale reading apparatus includes a scale 10 and a readhead 14 movable one relative to another. The readhead produces a pair of quadrature pulses which enable the generation of an incremental count corresponding to the displacement of the readhead 14 relative to a reference mark 80. The reference mark 80 is a permanent magnet mounted on the scale substrate inside a non-ferromagnetic casing 90. A pair of differential Hall sensors 62A,B within the readhead, and associated processing circuitry generate a step-change ZERO pulse when the readhead 14 and scale 10 are in a particular relative position. This relative position can be adjusted to enable corresponding adjustment of the relative phase of the quadrature pulses emitted from the readhead and the ZERO pulse, by means of a ferromagnetic adjusting screw 92.Type: GrantFiled: October 20, 1997Date of Patent: April 18, 2000Assignee: Renishaw PLCInventor: Peter G Holden
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Patent number: 6029363Abstract: A self-calibrating position transducer system and method uses the position transducer itself as a position reference during calibration, thus eliminating using an external reference during calibration. The transducer signals are sampled at a plurality of evenly-spaced positions within each sampled scale wavelength, using the transducer itself as a position reference. The calibration values for the DC signal offsets, the amplitudes and non-orthogonality of the fundamental signals, the amplitudes of the signal harmonic components and position offsets are then determined using Fourier analysis techniques. The transducer signals are corrected using the determined calibration values, which are in turn used to revise the stored calibration values in anticipation of the next calibration operation. The self-calibrating position transducer uses the stored calibration values to enhance its accuracy.Type: GrantFiled: April 3, 1998Date of Patent: February 29, 2000Assignee: Mitutoyo CorporationInventors: Karl G. Masreliez, Nils Ingvar Andermo
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Patent number: 6018881Abstract: A position measuring system that includes a scale graduation and a scanning element, wherein the scanning element moves relative to the scale graduation along a measurement direction so as to generate position-dependent, intensity-modulated output signals. The scanning element includes a dynamic characteristic, which has saturation areas adjoining both sides of an at least partially approximately linear operating area, in which no significantly changed output signal results any more, even when the input signal changes. The scanning gap (d) between the scale graduation and the scanning element is selected in such a way that as the scanning element moves over its entire measurement range a modulation between maximum input signals, which are located in the saturation areas of the dynamic characteristic, takes place.Type: GrantFiled: December 15, 1997Date of Patent: February 1, 2000Assignee: Dr. Johannes Heidenhain GmbHInventor: Alfons Spies
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Patent number: 5901458Abstract: An electronic caliper having a reduced offset position transducer that uses two sets of coupling loops on a scale to inductively couple a transmitter winding on a read head on a slide to one or more receiver windings on the read head. The transmitter winding generates a primary magnetic field. The transmitter winding is inductively coupled to first loop portions of first and second sets of coupling loops by a magnetic field. Second loop portions of the first and second sets of coupling loops are interleaved and generate secondary magnetic fields. A receiver winding is formed in a periodic pattern of alternating polarity loops and is inductively coupled to the second loop portions of the first and second sets of coupling loops by the secondary magnetic fields. Depending on the relative position between the read head and the scale, each polarity loop of the receiver winding is inductively coupled to a second loop portion of either the first or second set of coupling loops.Type: GrantFiled: November 21, 1997Date of Patent: May 11, 1999Assignee: Mitutoyo CorporationInventors: Nils Ingvar Andermo, Karl G. Masreliez
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Patent number: 5842283Abstract: A position detection apparatus having a scale with resilient engaging portions that attach to a lower surface of the scale and engage insertion holes in a track rail into which fastening members are inserted for fixing the track rail to a bed. Also, a track rail unit that includes the position detection apparatus, and a guide unit that includes the track rail unit.Type: GrantFiled: August 6, 1996Date of Patent: December 1, 1998Assignee: Nippon Thompson Co., Ltd.Inventors: Takashi Yatsu, Kouji Obara, Takaaki Hagiya
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Patent number: 5798640Abstract: A passive magnetic position sensor is constructed of an electrically non-conductive, non-magnetic substrate on which a resistance layer and a soft-magnetic, electrically conductive bending-beam structure are arranged. The resistance layer and bending-beam structure are arranged at a constant distance apart partially overlapping each other. The distance apart is selected so that, under the action of a magnet device conducted along the overlapping region of the bending-beam structure and resistance layer, contact is produced between resistance layer and soft-magnetic bending-beam structure. In order to provide a position sensor which permits a precise tapping of voltage, the electrically conductively developed resistance layer has along its longitudinal direction a meander-like structure adjoined by taps which have contact surfaces on the regions opposite the soft-magnetic bending-beam structure.Type: GrantFiled: May 14, 1996Date of Patent: August 25, 1998Assignee: VDO Adolf Schindling AGInventors: Lothar Gier, Bernd Osterle, Rudolf Borchert, Wolfgang Porth, Sabine Stark, Werner Wallrafen
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Patent number: 5778547Abstract: An improved electronic combination square (10) comprising an elongate blade (12) constructed of a nonmagnetic material. An elongate conductor strip (14) constructed of a magnetic material is connected longitudinally into a recessed top surface of the blade (12). A head (16) is provided having two ninety degree angle sides (18), (20) and two forty five degree angle sides (22), (24) constructed of a non-magnetic material. A facility (26) is for allowing the head (16) to slide to any position along the blades (12) over the conductor strip (14) from either of the two ninety degree angle sides (18), (20). A structure (28) is for locking the head (16) to the blade (12) from either of the two ninety degree angle sides (18), (20). A component (30) in the head (16) is for actuating a signal magnetically, relative to the position of the head (16) on the conductor strip (14) in the blade (12).Type: GrantFiled: October 21, 1996Date of Patent: July 14, 1998Inventor: Kerry D. Wolken
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Patent number: 5716071Abstract: A rotary prime mover, preferably an electric motor, is remotely operable from the cab of the vehicle. A linkage couples the rotary prime mover to the pins of the slider assembly, wherein rotation of the rotary prime mover selectively moves the pin in and out registry with holes in a pair of rails on the trailer to prevent and permit relative movement between the rear tandem axle assembly and the trailer. A pin sensor is coupled to the linkage to detect whether the pins are in or out of registry with the holes in the rails and a counter is coupled between the rear tandem axle assembly and the trailer to determine with which of the holes in the rails the pins are aligned. A visual display is provided in the cab and coupled to the pin sensor and counter to communicate to the operator the registry of the pins and with which of the holes the pins are aligned.Type: GrantFiled: June 17, 1994Date of Patent: February 10, 1998Assignee: Patrick L. StanleyInventors: Patrick L. Stanley, Alan C. Lesesky, Bobby Weant
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Patent number: 5628120Abstract: The invention relates to a method and to an arrangement for measuring length or angles, in which method use is made of a tape-shaped transmitter element (1) which is provided with markings and is designed to be pulled out of and pushed into a housing (6), easing or the like, the latter being provided with at least one sensor (4, 5) for detecting the markings on the transmitter element, and with an electronics unit (33) for converting signals from the sensor into length measurements or angle measurements.Type: GrantFiled: July 31, 1995Date of Patent: May 13, 1997Inventor: Jan G. Sergenius
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Patent number: 5566216Abstract: A tool which can be remotely operated to precisely measure the downcomer annulus width at the elevation of the top guide support ring. The measuring tool has a support frame adapted to be grappled and then hooked onto the upper rim of the shroud, and a measuring subassembly mounted on the support frame. The measuring subassembly has a contact block mounted on a bearing-mounted slider. The slider is translatable between a retracted (i.e., "home") position and an extended position in response to actuation of a cylinder mounted on the support frame. When the tool is properly installed on the rim of the shroud, the slider travels radially outward in response to actuation of the cylinder until the contact block abuts the opposing inner surface of the reactor pressure vessel wall, i.e., the slider is stopped.Type: GrantFiled: September 22, 1995Date of Patent: October 15, 1996Assignee: General Electric CompanyInventor: Khanh T. Ly
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Patent number: 5546672Abstract: A method and apparatus for detecting magnetic marks on a wireline logging cable and for more accurately making depth measurements during logging is described. The method uses depth-based, rather than time-based, samples and calculations. A Hall Effect sensor samples the cable at regular depth intervals approximated by an encoder mechanism. The signal values from the Hall Effect sensor are signal processed to better discriminate the precise location of the magnetic marks on the cable. The location of the magnetic marks is used to refine the depth measurements from the encoder mechanism. Depth-based sampling eliminates detection dependence on cable speed, enhances detection ability, reduces computational load, and leads to more accurate determination of the location of magnetic marks.Type: GrantFiled: November 9, 1994Date of Patent: August 20, 1996Assignee: Schlumberger Technology CorporationInventors: Heather A. Campbell, Terry L. Mayhugh, Marvin W. Rasmussen, Guy Vachon
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Patent number: 5535142Abstract: A circuit arrangement for an inductive position indicator which comprises a measurement coil arrangement having a plurality of measurement coils forming at least first and second groups, each of which supplies a measurement coil signal that varies with the position to be monitored, includes a computing circuit which, to produce a measurement signal, interlinks at least two signals derived from the measurement coil signals, in accordance with a predetermined algorithm. The circuit arrangement further includes a multiplexer for feeding a variable selection of measurement coil signals to the further processing, to achieve a high level of resolution and measurement accuracy.Type: GrantFiled: July 21, 1993Date of Patent: July 9, 1996Inventors: Walter Mehnert, Thomas Theil
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Patent number: 5488782Abstract: A scale plate arrangement is adapted to be attached to a machine tool for detecting, for example, position and velocity of an object. The scale plate arrangement includes a scale-plate base and a scale plate which has a scale thereon. The scale plate is welded to the scale-plate base. With this, it is not necessary to use an adhesive or a fixing member to attach the scale plate to the scale-plate base. In case that the scale plate has a magnetic scale and that the scale-plate base is made of a magnetic material, the scale-plate base is formed with a recess which is positioned under the magnetic scale. With this, magnetic influence of the scale-plate base on the magnetic scale can be prevented.Type: GrantFiled: April 29, 1994Date of Patent: February 6, 1996Assignee: Sony Magnescale Inc.Inventor: Osamu Ochiai
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Patent number: 5442865Abstract: A position sensor has an electrically non-conductive substrate with a resistance layer and a conductor track serving as a potentiometer tap arranged parallel thereto, and a second, electrically conductive substrate. At least one substrate is of resilient construction, and at least one of the substrates has a soft-magnetic layer. A magnet is mounted for guidance in the direction of the conductor track, and is located at a constant distance away from the conductive track. The two substrates are spaced apart at a distance allowing contact to be produced under magnetic action. The resistance layer and the conductor track each have structural parts which engage alternately into each other along a path of movement of the magnet.Type: GrantFiled: January 4, 1994Date of Patent: August 22, 1995Assignee: VDO Adolf Schindling AGInventor: Werner Wallrafen
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Patent number: 5386642Abstract: A position measuring instrument for measuring the relative position of two objects movable relative to one another. The position measuring instrument comprises a periodic measurement scale division having a period t and a scanner unit, wherein the scanner unit and the periodic measurement scale division move relative to one another in a measuring direction. In addition, the scanner unit comprises four groups (A-D) each comprising at least four magnetoresistive elements (A.sub.n -D.sub.n) (n=1, 2, 3, 4, . . .), which are interconnected in the form of a series-parallel circuit to form a half bridge circuit having an upper branch and a lower branch. The upper branch comprises a magnetoresistive element from each group (A-D) and the lower branch comprises a corresponding magnetoresistive element from each group (A-D). Furthermore, the magnetoresistive elements of the upper branch are offset from the corresponding magnetoresistive elements of the lower branch by t/2.Type: GrantFiled: February 4, 1993Date of Patent: February 7, 1995Assignee: Dr. Johannes Heidenhain GmbHInventors: Alfons Spies, Gerald Metz
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Patent number: 5327653Abstract: A magnetic-electronic linear measurement gage for measuring workpiece miter lengths for picture and window frames and the like includes a gage bed on which a workpiece may be removably mounted, a stop body slidably mounted on the gage bed having a stop which may butt against a workpiece mitered end, and length and width scales and scanning units associated with the gage and the stop body generating output signals in response to the scanning of the scales. The output signals are received and converted by a CPU to generate a linear measure output signal which may be inputted to a digital LED display for visually displaying the linear measure corresponding to the workpiece length so measured.Type: GrantFiled: August 19, 1992Date of Patent: July 12, 1994Inventors: Robert T. Pistorius, Thomas H. Hoffmann
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Patent number: 5287630Abstract: A distance or position detecting device has a movable member forming a measuring ruler and a detector in the form of a primary coil and a plurality of secondary coils forming together a stationary member. The measuring ruler is movable coaxially inside a hollow core of the primary coil. The measuring ruler is made of a plurality of sections alternating with one another along the length of the ruler, whereby these sections have different discernible characteristics, for example, magnetic characteristics and nonmagnetic characteristics. The individual ruler sections are assembled along the length of the ruler in such a manner that a respective limited number of neighboring ruler sections are arranged in an encoded form so that the encoding provides an absolute position indication. Such a structure is simple and hence cost effective in any of its operational states. An accurate and absolute position indication is thus possible.Type: GrantFiled: September 3, 1991Date of Patent: February 22, 1994Assignee: Hottinger Baldwin Messtechnik GmbHInventor: Peter Geisler
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Patent number: 5174041Abstract: A method and an electronic slide caliper serve for measuring a length. The slide caliper comprises a rule and a slide which is arranged on the rule for longitudinal displacement and which is provided with two sensors which are offset relative to each other in the longitudinal direction in such a way that the zero passages of the signals generated by the sensors will not coincide. In order to be able to measure the lengths even in the presence of considerable drifts, the zero passages (ND) of the signals are determined by determining first maximum values (MX) and minimum values (MN) of the signal values (U) and deriving thereafter the zero passages (ND) as arithmetic mean value. By taking the average of a larger number of zero passages one then determines the respective zero level (U.sub.N).Type: GrantFiled: May 31, 1991Date of Patent: December 29, 1992Assignee: AktiengesellschaftInventor: Marcel Lorenz
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Patent number: 5136883Abstract: A liquid level gage system is disclosed. This system includes a displacer secured to a cable and movable in response to winding or unwinding said cable around or from around a rotatable drum. The rotatable drum is coupled to a driven shaft, and a drive assembly is provided to drive the driven shaft. An indicator subsystem is included which provides an indication of a change in the apparent weight of the displacer as the displacer is moved across a liquid level. A strain gage is a key component of the indicator subsystem. In one embodiment, an assembly is provided for powering the indicator subsystem and transferring data from the indicator subsystem which involves two pair of coils. In another embodiment, the gage system can be effectively remotely programmed using light signals.Type: GrantFiled: August 24, 1990Date of Patent: August 11, 1992Inventor: Louis J. Jannotta
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Patent number: 5074053Abstract: A linear sensing device containing an electrically conductive reed strip which, in the presence of an external actuating horseshoe magnet, makes electrical contact to a resistive strip at the location of that magnet. The conductive reed strip is attached along one end to a supporting member, formed from a material with coefficient of thermal expansion similar to the reed strip, to prevent warping of the reed strip over a range of environmental temperatures. The sensing device is of a modular construction with elongate cap, to which the resistive strip is attached, and an elongate base, to which the reed strip support member is attached. The cap and base mate together to form an inner container which then slides into an outer container.Type: GrantFiled: August 13, 1990Date of Patent: December 24, 1991Inventor: John D. West
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Patent number: 5036597Abstract: A securing device composed of a plurality of components for a measuring apparatus used for determining the positions of two structural members which are movable relative to each other. The measuring apparatus includes a graduation, a carrier member carrying the graduation and a scanning device for scanning the graduation. The scanning device is guided at a constant distance from the graduation. The scanning device is fastened to one of the movable structural members by means of an assembly base. Spacer members are used for maintaining the securing device in an intended position relative to the carrier member. Each component of the securing device is a unit which can be separately attached to the carrier member. The components include interacting elements for connecting the components in a securing position.Type: GrantFiled: December 11, 1990Date of Patent: August 6, 1991Assignee: Dr. Johannes Heidenhain gmbHInventors: Bernhard Falkinger, Reinhold Schopf
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Patent number: 5016359Abstract: A scale arrangement is designed for monitoring relative displacement between first and second members. The scale arrangement comprises an elongated scale having end portions at both ends thereof, a pair of receptacles respectively receiving the end portions, a hollow member receiving the scale therein, the hollow member being formed into essentially quadrate cross section, a head slidingly mounted on the scale for axial movement therealong for reading scale to generate a read scale indicative signal, a head slider associated with the head for axial movement with the head, the end portions, the receptacles and the head sliders being positioned on respectively associated one of first and second members with respect to the end portions, position of the head slider being determined with respect to a reference plane set on the outer peripheral plane on the hollow member in relation to the end portion.Type: GrantFiled: May 30, 1989Date of Patent: May 21, 1991Assignee: Sony Magnescale Inc.Inventors: Kazuo Nagaoka, Tadao Hatano, Sadao Wakabayashi, Takamitsu Shimizu
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Patent number: 5007177Abstract: The incremental measuring system comprises a scale member with an incremental scale and a scanning unit comprising scanning sets for generating analog measured-value signals in response to the scanning of the scale. The system also comprises an evaluating unit for deriving digital countable signals from the analog measured-value signals and for generating a reference pulse. At least one pair of reference marks are spaced along the scale on a carrier releasably fixed to the scale member. The scanning unit comprises a reference mark scanning set to scan the reference marks and connected to the evaluating unit. A reference point which registers with a selected increment of the scale is disposed on the carrier between the reference marks of the pair and can be defined by the distances from the reference point to the reference marks, and these distances are stored in a memory.Type: GrantFiled: January 22, 1990Date of Patent: April 16, 1991Assignee: RSF-Elektronik Gesellschaft m.b.H.Inventors: Heinz Rieder, Max Schwaiger
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Patent number: 4991311Abstract: A magnetic linear scale unit comprises a magnetic scale and mounting blocks which are designed to be rigidly fixed to one of relatively displaceable mechanical components, about which magnitude or stroke of the relative thrusting displacement is to be measured. The magnetic scale has end sections to be mounted on the mounting blocks. The end sections have round peripheral portion mating with the mounting block. At least one of the end section also includes a structural component which allows pivotal movement of the magnetic scale relative to the mounting block for fine adjustment of the axis of the magnetic scale relative to the axis of relative movement of the mechanical components. A scale channel is free from the mounting block and simply serves as the magnetic shield. Therefore, the scale channel of the invention is substantially free from the accuracy requirement and production error of the scale channel and will never affect measurement of the displacement magnitude.Type: GrantFiled: June 26, 1989Date of Patent: February 12, 1991Assignee: Sony CorporationInventors: Kazuo Nagaoka, Sadgo Wakabayashi, Yoshihiko Kanasugi, Tadao Hatano
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Patent number: 4843729Abstract: A magnetic linear scale unit comprises a magnetic scale and mounting blocks which are designed to be rigidly fixed to one of relatively displaceable mechanical components, about which magnitude or stroke of the relative thrusting displacement is to be measured. The magnetic scale has end sections to be mounted on the mounting blocks. The end sections have round peripheral portion mating with the mounting block. At least one of the end section also includes a structural component which allows pivotal movement of the magnetic scale relative to the mounting block for fine adjustment of the axis of the magnetic scale relative to the axis of relative movement of the mechanical components. A scale channel is free from the mounting block and simply serves as the magnetic shield. Therefore, the scale channel of the invention is substantially free from the accuracy requirement and production error of the scale channel and will never affect measurement of the displacement magnitude.Type: GrantFiled: August 18, 1987Date of Patent: July 4, 1989Assignee: Sony Magnescale, Inc.Inventors: Kazuo Nagaoka, Sadao Wakabayashi, Toshihiko Kanasugi, Tadao Hatano
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Patent number: RE35084Abstract: A method and an electronic slide caliper serve for measuring a length. The slide caliper comprises a rule and a slide which is arranged on the rule for longitudinal displacement and which is provided with two sensors which are offset relative to each other in the longitudinal direction in such a way that the zero passages of the signals generated by the sensors will not coincide. In order to be able to measure the lengths even in the presence of considerable drifts, the zero passages (ND) of the signals are determined by determining first maximum values (MX) and minimum values (MN) of the signal values (U) and deriving thereafter the zero passages (ND) as arithmetic mean value. By taking the average of a larger number of zero passages one then determines the respective zero level (U.sub.N).Type: GrantFiled: December 15, 1994Date of Patent: November 14, 1995Assignee: PAV Praezisions-Apparatebau AktiengesellschaftInventor: Marcel Lorenz
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Patent number: RE35918Abstract: A stem load determining system comprises a method and apparatus for determining the load developed on a threaded stem, including a valve stem driven by a valve operator. An integral component of the apparatus is a stem strain transducer uniquely designed to girp a threaded stem to define a guage length on the threaded stem and to detect and measure deformation of the stem at the guage length when subjected to a compressive or tensile load.Type: GrantFiled: March 27, 1991Date of Patent: October 13, 1998Assignee: Westinghouse Electric CorporationInventors: Paul Gene Anderson, John A. McMennamy