Permanent Magnets Patents (Class 335/302)
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Patent number: 5666097Abstract: A magnetizer for use in forming periodic magnetic fields is provided which utilizes two magnet structures which are coaxially aligned with one another. Two stages of magnetic cores are inserted into a gap between the two magnet structures. The stages of magnetic cores each have an upper and lower portion, each portion of which has grooves and ridges which mirror each other. The two different stages of magnetic cores are fabricated such that the respective grooves and ridges are offset and the grooves and ridges of one stage of magnetic core opposes the grooves and ridges, respectively, of the other stage of magnetic core. The two stages of magnetic cores can be active or passive magnetic material. In operation, the two magnetic structures form a uniform transverse magnetic field which passes through a working cavity of the magnetizer.Type: GrantFiled: June 14, 1996Date of Patent: September 9, 1997Assignee: The United States of America as represented by the Secretary of the ArmyInventor: Herbert A. Leupold
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Patent number: 5655747Abstract: A solenoid valve for an irrigation control unit comprises a cut-off element movable inside a respective seat between a closed position and an open position. The cut-off element defines inside the seat a chamber in constant communication with the inlet of the solenoid valve, so that the pressure exerted on the cut-off element by the water present at the inlet of the solenoid valve is balanced by the pressure exerted on the cut-off element by the water present in the chamber. The cut-off element is provided with a passing conduit that can be opened so that the chamber can be put in communication with the outlet of the solenoid valve. Since the pressure exerted on the cut-off element by the water present at the inlet of the solenoid valve is no longer balanced by the pressure exerted on the cut-off element by the water present in the chamber, the cut-off element is displaced by the thrust of the water present at the inlet of the solenoid valve in said open position.Type: GrantFiled: December 8, 1995Date of Patent: August 12, 1997Assignee: Claber S.p.a.Inventor: Claudio Pasut
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Patent number: 5634755Abstract: A magnetic drain bolt comprising: a bolt body and a magnet, the bolt body comprises a male-threaded member and a head member, the male-threaded member has an axial bore formed at a bottom end thereof for receiving the magnet, the male-threaded member further has a substantially circular lip extending axially inward at a bottom edge of the axial bore; the magnet consists of a cylindrical base and a cylindrical projecting extremity, the cylindrical base is sized to fit within the axial bore and has a diameter slightly larger than an inner diameter of the circular lip, the cylindrical projecting extremity extends axially from the cylindrical base and has a diameter slightly smaller than an inner diameter of the circular lip and thereby defines an indented circular shoulder along a bottom edge of the cylindrical base and along a top edge of the cylindrical projecting extremity, wherein the cylindrical base is fitted within the axial bore and the circular lip extends over the indented circular shoulder against theType: GrantFiled: April 1, 1996Date of Patent: June 3, 1997Assignee: Illinois Tool Works Inc.Inventor: James D. Jones, Jr.
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Patent number: 5631093Abstract: Nonmagnetized permanent magnet material is heated in a pattern by a laser beam to a localized temperature above the Curie point or a temperature sufficient to reduce the coercivity sufficiently for an external field to magnetize the pattern in the direction of the field. Magnets so produced can have very high pole density, digital encoding and analog patterns having gradually varying local field strength. Alternating pole magnets of this type can be used for stepper motor magnets.Type: GrantFiled: November 8, 1991Date of Patent: May 20, 1997Assignee: General Motors CorporationInventors: Thomas A. Perry, John R. Bradley, Thaddeus Schroeder, Carlton D. Fuerst
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Patent number: 5627505Abstract: A magnetic cylinder for holding printing plates and the like having a drum of non-magnetic material with recesses on the drum surface containing a series of uninterrupted elongated permanent ceramic magnets extending substantially the length of the cylinder in an axial direction with pole pieces between adjacent magnets.Type: GrantFiled: July 1, 1996Date of Patent: May 6, 1997Assignee: T. D. Wright, Inc.Inventor: Thaddeus T. Iwaszek
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Patent number: 5622351Abstract: Disclosed is a water-supply valve of a washing machine in which the consumption of electric power can be minimized in opening and closing the valve to supply water into and block off the water supply into a washing tub of the washing machine. In the water-supply valve, an actuator rod is elevated against downward biasing force of a spring by a magnetic force of the first solenoid generated by applying an electric current thereto, and then is retained at its uppermost position by the attractive force of the permanent magnet. And, the actuator rod starts to be lowered by a magnetic force of the second solenoid generated by applying an electric current thereto, and is retained at its lowermost position by the downward biasing force of the spring.Type: GrantFiled: December 23, 1994Date of Patent: April 22, 1997Assignee: Daewoo Electronics Co., Ltd.Inventor: Jinsoo Kim
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Patent number: 5623241Abstract: A permanent magnet structure includes a generally shaped frame made of a magnetic material and a pair of opposite polarity magnet members mounted on the opposed surfaces of the legs of the U. The connecting element of the U which connects the legs, is disposed at a sufficient distance from the magnets so that the resulting magnetic field passes substantially entirely between the magnets and through the arms and so that no substantial eddy currents are induced in the connecting element during imaging. Between the connecting element and the magnets, there is disposed a non-conductive, non-magnetic separating member which contacts the two arms and tends to keep them apart. The separating member is so positioned relative to the connecting member and the magnets that effects of the force between the two magnets and the force produced by the magnetic field passing through the arms and connecting element are counterbalanced. This results in a structure which is mechanically stable.Type: GrantFiled: April 17, 1995Date of Patent: April 22, 1997Assignee: Magna-Lab, Inc.Inventor: Lawrence A. Minkoff
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Patent number: 5621369Abstract: A flexible magnetic sheet is made of a rubbery synthetic material in which magnetic ferrite particles have been embedded and which one surface of the sheet has a grid pattern of ridges and depressions. The magnetic material is magnetized so that one pole is one each surface. The magnetic lines of force are generated substantially in a plane.Type: GrantFiled: September 18, 1995Date of Patent: April 15, 1997Inventors: Harris L. Gardner, William H. Gardner, heir
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Patent number: 5610568Abstract: A magnetic bar includes a magnetized core extending along a median line between two parallel polepieces extending along the magnetized core transversely to its permanent magnetization. The magnetized core embodies, substantially along the median line, a discontinuous succession of identical separate magnets. The magnetic bar can be used in the manufacture of magnetic bearings and thrust bearings.Type: GrantFiled: July 26, 1994Date of Patent: March 11, 1997Assignee: Societe Nationale Industrielle et AerospatialeInventor: Oliver Marroux
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Patent number: 5539368Abstract: The magnet roll of the present invention includes a shaft and a permanent magnet member fixed to the shaft, the permanent magnet member being composed of a hollow, cylindrical magnet body, and a magnetic pole piece fixed to a recess of the hollow, cylindrical magnet body, the hollow, cylindrical magnet body having a plurality of axially extending magnetic poles arranged circumferentially on the surface, the magnetic pole piece being provided with two magnetic poles having the same polarity for constituting a developing magnetic pole, and a thermally demagnetized portion being formed substantially at a center of the developing magnetic pole such that the permanent magnet member generates a magnetic flux density distribution having two peaks of the same polarity at a position of the developing magnetic pole.Type: GrantFiled: October 1, 1993Date of Patent: July 23, 1996Assignee: Hitachi Metals, Ltd.Inventor: Keitaro Yamashita
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Patent number: 5532665Abstract: A force rebalance accelerometer includes a proof mass suspended by one or more flexures between stationary mounted upper and lower excitation rings. Pick-off capacitance plates formed on opposing sides of the proof mass form capacitance elements whose capacitance varies in response to displacement of the proof mass to provide a displacement signal. The displacement signal is applied to one or more electromagnets, used to force the proof mass back to a null or at-rest position. The drive current applied to the electromagnets thus represents the force or acceleration applied to the accelerometer. The electromagnets include a magnet and a pole piece which forms a magnetic return path. In order to relieve stresses due to thermal expansion, the magnet is spaced apart from the pole piece to enable the bonding area to be constrained to a minimum which, in turn, reduces the overall stress on the accelerometer.Type: GrantFiled: January 21, 1994Date of Patent: July 2, 1996Assignee: AlliedSignal, Inc.Inventors: Steven A. Foote, Damon R. Stoddard
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Patent number: 5515020Abstract: A premagnetizing head for charging the magnetizable pigment of characters printed on a document includes a permanent magnet (10) whose one pole is connected to a magnetically conductive metal plate (12) which extends away from the magnet (10) in a direction generally transversal to the north-south pole axis of the magnet and up to the document (D) whose characters are to be magnetized and read. The permanent magnet (10) is oriented so that its northpole-southpole axis will extend generally parallel with the plane of the document (D) to be read.Type: GrantFiled: May 12, 1993Date of Patent: May 7, 1996Assignee: ICL Systems AktiebolagInventor: Allan Stiernspetz
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Patent number: 5506557Abstract: A high performance radial anisotropic cylinder-shape ferrite magnet for use in a motor to lower its noise and enable miniaturization thereof is formed of an integrated one-piece body formed of sintered Sr and/or Ba ferrite powders and has an axially-extending slit that is created before the body is sintered to reduce internal stress due to shrinkage. The slit can extend in parallel to both the axial and radial directions of the body, diagonally to both the axial and radial directions, or diagonally to the radial direction and parallel to the axial direction. The slit can be filled with a resin material.Type: GrantFiled: January 18, 1994Date of Patent: April 9, 1996Assignee: Sumitomo Special Metals Company, LimitedInventors: Takehisa Sakaguchi, Takahiro Sunaga, Jun Hoshijima
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Patent number: 5488341Abstract: A permanent magnet member composed of an integral sintered body made of a ferrite magnet material, the integral sintered body including a cylindrical center portion and shaft portions formed at the opposite ends of the cylindrical center portion and each having a smaller diameter than that of the cylindrical center portion, the cylindrical center portion being provided with a plurality of magnetic poles extending axially and arranged circumferentially on an outer surface of the cylindrical center portion.Type: GrantFiled: June 6, 1994Date of Patent: January 30, 1996Assignee: Hitachi Metals, Ltd.Inventors: Mikio Yamamoto, Keitaro Yamashita, Katsunobu Kiriyama
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Patent number: 5467769Abstract: A magnetic field generating apparatus has a permanent magnet arrangement for generating a magnetic field in a magnetic field generating space and a yoke arrangement for forming magnetic circuits for generation of the magnetic field together with the permanent magnet arrangement. The yoke arrangement includes a first pair of yokes arranged facing each other, a second pair of yokes arranged facing each other through which the first pair of yokes are magnetically connected to each other, a third pair of yokes arranged between one end of one of the first pair of yokes and one end of one of the second pair of yokes and between the other end of the one of the first pair of yokes and one end of the other of the second pair of yokes, respectively, and yoke moving units for independently moving the one of the first pair of yokes and each of the second pair of yokes with respect to the third pair of yokes, respectively.Type: GrantFiled: February 16, 1994Date of Patent: November 21, 1995Assignees: Hitachi Medical Corporation, Sumitomo Special Metals Co., Ltd.Inventors: Hitoshi Yoshino, Shigeo Hashimoto
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Patent number: 5462054Abstract: A permanent magnet assembly used for creating a uniform magnetic field across a portion of an air gap has a permanent magnet grouping, including a first, principal magnet, a pole piece contacting said principal magnet, and a set of auxiliary magnets extending about the periphery of the pole piece. Two such magnet groupings are positioned within a test chamber, separated a spacer, with the magnet groupings and the chamber defining the air gap across which the magnetic field extends. The strength and uniformity of the magnetic field is adjusted by including a second set of auxiliary permanent magnets or a set of electromagnetic shim coils positioned within the air gap surrounding and overtapping a portion of the air gap. Further adjustment of the magnetic field is accomplished shaping the front surfaces of the pole pieces, thus affecting the shape and direction of the resulting magnetic field.Type: GrantFiled: March 31, 1994Date of Patent: October 31, 1995Assignee: Advanced Techtronics, Inc.Inventors: Uri Rapoport, Richard Panosh
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Patent number: 5428332Abstract: A process and apparatus for permitting the magnetization of flexible hard magnetic materials in the form of sheets or strips, such as magnetic rubber, wherein opposing arrays formed from alternating magnetic disks and flux conducting elements are use in sets of two with opposing polar moments such as to induce a magnetic flux in the gap between the discs. The width of the magnetic disk and flux conducting elements, respectively, are selected to optimize the magnetic pull strength of the material. At the array ends are flux conducting elements that are about 1/2 (i.e., from about 0.25 to about 0.75, and preferably from about 0.4 to 0.6) of the width of the internal flux conducting elements. A material to be magnetized is passed between the array sets in contrast with both disks and consequently imprinted with magnetic poles. The magnetized properties of the material is enhanced by passing the material through a second set of arrays which are axially offset with respect to the first set of arrays.Type: GrantFiled: May 26, 1994Date of Patent: June 27, 1995Assignee: RJF International CorporationInventors: Raymond C. Srail, Richard A. Glover, Thomas R. Szczepanski, Eric M. Weissman, Frederic W. Kunig
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Patent number: 5421722Abstract: A magnet arrangement is provided having mutually opposing, cylindrical magnets for securing a prosthesis, one magnet being implanted or fastened to an implant and the opposing magnet being fitted in a prosthesis, in particular a dental prosthesis, wherein the bearing surface of the one magnet is of convex configuration and the bearing surface of the opposing magnet is of concave configuration corresponding to the radius of curvature of the convex bearing surface of the other magnet.Type: GrantFiled: June 11, 1993Date of Patent: June 6, 1995Inventor: Hartmut Stemmann
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Patent number: 5416457Abstract: A lateral orientation type of anisotropic permanent magnet having a face of magnetic application and at least one lateral face adjacent to the face of magnetic application. An axis of easy magnetization of particles of a magnetic powder constituting the permanent magnet is oriented substantially along lines from the lateral face toward the face of magnetic application to increase the peak value of the surface magnetic flux density at the face of magnetic application.Type: GrantFiled: August 10, 1994Date of Patent: May 16, 1995Assignee: Kawasaki Steel CorporationInventors: Satoshi Nakatsuka, Akira Yasuda, Itsuo Tanaka, Koichi Nushiro, Takahiro Kikuchi
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Patent number: 5406240Abstract: In combination with an electric apparatus emitting electromagnetic radiation, an arrangement for reducing the radiation hazards on an operator in front of the apparatus is provided, the arrangement comprising at least three magnetic devices approximately located at the apices of a triangle in front of the apparatus, each magnetic device including a closed housing made of a nonmagnetic material, a permanetn magnet located within the housing for producing a magnetic flux, and a bar of non-magnetic material located within the housing in a defined spaced-apart relationship such that the bar of non-magnetic material is placed in the effective flux area of the permanent magnet, the magnetic devices being positioned in front of the apparatus such that each permanent magnet has its north pole opposed to the south pole of the other magnets and such that each bar of non-magnetic material is situated behind the permanent magnet associated thereto.Type: GrantFiled: November 12, 1993Date of Patent: April 11, 1995Inventor: Francois E. Deckers
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Patent number: 5400786Abstract: An MRI magnet arrangement comprises, an annular electromagnet defined by a coil, an annular shim of magnetic material coaxially disposed within the coil, first permanent magnet means having a field, the direction of which is the same as the field of the coil, disposed coaxially within the said shim and second permanent magnet means disposed coaxially within the said first permanent magnet means, the field of which is arranged to be opposite in direction to the field produced by the said first permanent magnet means, the arrangement being such that the magnetic field produced in an imaging volume within the said second permanent magnet means is substantially homogeneous.Type: GrantFiled: January 4, 1994Date of Patent: March 28, 1995Assignee: Oxford Magnet Technology LimitedInventor: Jonathan L. Allis
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Patent number: 5399933Abstract: A pair of ring-shaped magnets, or magnetic pole pieces, having the same magnetic field strength, or magnetic flux density, are disposed about the neck portion of a cathode ray tube (CRT) for statically converging a plurality of inline electron beams on the CRT's faceplate. The magnetic ring pair includes an inlet ring magnet facing the CRT's base and an outlet ring magnet facing the CRT's faceplate, with the inlet ring magnet having a thickness greater than that of the outlet ring magnet along the CRT's longitudinal axis. The inlet ring magnet thus exerts a larger off-axis force on the electron beam than the outlet ring magnet because of the longer beam path in the inlet ring magnet to permit the magnetic ring pair to apply a maximum convergence correction for substantially misconverged electron beams and a minimum convergence correction when the beams are in convergence.Type: GrantFiled: May 20, 1993Date of Patent: March 21, 1995Assignee: Chunghwa Picture Tubes, Ltd.Inventor: Sen-Su Tsai
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Patent number: 5399311Abstract: A magnet is formed as a ring magnet and magnetized by radial application of a magnetic field while the intensity of the magnetic field is changed periodically along the circumference of the ring magnet to give a circumferentially sinusoidal waveform distribution of magnetic flux density to the ring magnet in the magnetized state of the magnet.Type: GrantFiled: November 12, 1992Date of Patent: March 21, 1995Assignee: Daido Tokushuko Kabushiki KaishaInventors: Yasuaki Kasai, Hiyoshi Yamada, Norio Yoshikawa
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Patent number: 5387893Abstract: A permanent magnet magnetic circuit comprises a main magnet block having a pair of opposite outer surfaces. A pair of main magnetic poles of opposite polarities are disposed on the respective outer surfaces of the main magnet block. The main magnet block is provided with a channel defined between the pair of outer surfaces and the channel has a pair of inner surfaces corresponding to the respective outer surfaces of the main magnet block. The main magnet block is also provided with a pair of oppositely polarized compensating magnetic poles arranged on the respective inner surfaces for controlling any vector of the magnetic field directed from one of the main magnetic pole to the other main magnetic pole. A pair of adjusting magnet blocks are arranged on the respective inner surfaces to adjust the magnetic field directed from one of the main magnetic poles to the other magnetic pole.Type: GrantFiled: March 9, 1993Date of Patent: February 7, 1995Assignee: Tokyo Electron LimitedInventors: Masami Oguriyama, Haruo Okano, Isahiro Hasegawa, Junichi Arami, Hiromi Harada
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Patent number: 5382905Abstract: The invention relates to a magnet apparatus for producing a uniform magnetic field for magnetic resonance imaging (MRI). The magnet apparatus is of the type having a pair of permanent magnet discs each of which has a hole in a central region and a yoke structure in which the magnet discs are held opposite to each other. For each magnet disc the yoke structure has an aperture which is in alignment with the hole in the magnet disc. As is usual, a pair of pole plates are attached to the opposite faces of the magnet discs, respectively, so as to produce a uniform magnetic field in a space between the two magnet discs. To ease visual observation of the object of imaging in the afore-mentioned space, such as the head part of a human body, the pole plate on each magnet disc is formed with a hole which is in alignment with the hole in the magnet disc. A video camera can be used. According to the need small pole pieces are attached to the surfaces of the holed pole plates to keep uniformity of the magnetic field.Type: GrantFiled: March 30, 1994Date of Patent: January 17, 1995Assignees: Shin-Etsu Chemical Co., Ltd., Yokogawa Medical Systems, Ltd.Inventors: Koji Miyata, Yuji Inoue
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Patent number: 5367278Abstract: A magnet holding structure comprising a magnet holder for holding a permanent magnet and a mounting frame formed integrally with a container such as a plastic basket for holding the magnet holder, the mounting frame including at least one pair of projecting walls having an engaging pawl on each of opposed inner surfaces thereof and the magnet holder having engaging projections corresponding to the engaging pawls, the interval of the engaging projections being slightly larger than the interval of the engaging pawls.Type: GrantFiled: June 7, 1993Date of Patent: November 22, 1994Assignee: Kabushiki Kaisha Yoshikawakun KogyoshoInventor: Toshimichi Yoshikawa
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Patent number: 5350628Abstract: A magnetic material is provided which includes a discrete phase including grains made of a first substance which comprises a magnetic metal; and a continuous phase including a thin coating film made of a second substance which comprises a dielectric or insulating substance. The thin coating film is formed on the surface of the grains and has a mean thickness smaller than the mean particle size of the grains. The grains are separated substantially from each other by the thin coating film.Type: GrantFiled: November 19, 1992Date of Patent: September 27, 1994Assignee: Matsushita Electric Industrial Company, Inc.Inventors: Koichi Kugimiya, Yasuhiro Sugaya, Osamu Inoue, Ken Hirota, Mitsuo Satomi
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Patent number: 5347733Abstract: A magnetic name tag has a pole piece panel elongated in one direction and with opposite end portions. One or more magnets assembled with the pole piece panel establish respective separate, complete magnetic flux paths at each of the end portions. A magnetically attractive keep plate elongated in generally complementary relation to the pole piece panel carries indicia thereon. The keep plate is attracted towards the magnet by the magnetic flux paths which effect a stabilized magnetic holding attraction for the keep plate in any assembled orientation of the pole piece and magnet assembly relative to the keep plate.Type: GrantFiled: March 30, 1992Date of Patent: September 20, 1994Inventor: Richard W. Whittington
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Patent number: 5347253Abstract: A non-magnetic case 3 made of acrylic acid or like synthetic resin has a case body 3a, a lid 3b and a right hexahedron shape. The case body 3a has a substantially spherical accommodation space 3c in which a spherical magnet body 2 having paired N and S poles arranged in a uni-axial direction is sealed together with oil or a like transparent liquid having a high specific gravity and also having a considerably high viscosity to provide buoyancy to the magnet body 2 and facilitate the rotation thereof with a lubricating action. The clearance between the magnet body 2 and the wall surface of the accommodation space 3c is set to be small such that the magnet body 2 can be rotated smoothly. The case 3 with the magnet body 2 therein is applicable to combination toys such as toy blocks and puzzle sets or various attracting articles having mutual attraction requirement. The thickness of a central portion of each side wall of the case is reduced to facilitate the attraction of the magnet bodies to each other.Type: GrantFiled: July 23, 1993Date of Patent: September 13, 1994Assignee: MagX Co., Ltd.Inventor: Konomu Ogikubo
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Patent number: 5345130Abstract: A permanent magnet rotor is shaped to optimize the flux distribution thereabout. In one embodiment, cut-outs in the rotor core between magnetic poles forces more of the magnetizing flux, i.e., that which would normally be distributed about the transition zone between the poles, into the main part of the poles, resulting in a substantially trapezoidal flux distribution that is substantially flat over approximately the central 120.degree. of each respective 180.degree. half-cycle thereof. In an alternative embodiment, the rotor core is shaped to be substantially square with rounded edges. Permanent magnet material is molded onto the square-shaped rotor core to form a plurality of magnetic poles such that the flux distribution about the rotor core is substantially sinusoidal.Type: GrantFiled: April 28, 1993Date of Patent: September 6, 1994Assignee: General Electric CompanyInventors: Gerald B. Kliman, Eike Richter
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Patent number: 5345207Abstract: The invention relates to a magnet configuration with permanent magnets (5, 6) around a yoke (2, 3, 4) connecting these permanent magnets (5, 6). The magnetic field strength of this magnet configuration is varied thereby that in the region of the yoke (2, 3, 4) at least one rotatable body (8) is provided which comprises at least two spatially separated materials (9, 10) with different magnetic properties.Type: GrantFiled: December 24, 1992Date of Patent: September 6, 1994Assignee: Leybold AktiengesellschaftInventor: Thomas Gebele
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Patent number: 5337033Abstract: A permanent magnet assembly for stably fixing a denture comprising a permanent magnet, a casing made of a corrosion-resistant, magnetic material having a cavity for receiving the permanent magnet, and a seal plate for covering an opening of the casing to prevent the permanent magnet from exposing outside, the seal plate consisting of a seal ring member made of a corrosion-resistant, non-magnetic material and a disc plate made of a corrosion-resistant, soft-magnetic material and having substantially the same outer diameter as the inner diameter of the seal ring member, the seal ring member and the disc plate being concentrically arranged in the same plane, the disc plate being welded to the seal ring member in their abutment, and the seal ring member being welded to the casing. Laser welding is utilized.Type: GrantFiled: January 15, 1992Date of Patent: August 9, 1994Assignee: Hitachi Metals, Ltd.Inventors: Yohsuke Kinouchi, Minoru Ai, Hiroshi Mizutani, Osamu Okuno, Kiyotaka Yamauchi, Akira Yamataka, Hiroya Suzuki
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Patent number: 5333767Abstract: A wrist mounted magnetic holder for small articles such as screws, nails, bolts, drill bits and the like having a non-ferrous material housing with a ceramic magnet polarized into two distinct regions and a flux concentrator for increasing the magnetic flux density at the holding surface.Type: GrantFiled: February 16, 1993Date of Patent: August 2, 1994Inventor: Steven P. Anderson
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Patent number: 5320103Abstract: A permanent magnet assembly used for creating a uniform magnetic field across a portion of an air gap has a permanent magnet grouping, including a first, principal magnet, a pole piece contacting said principal magnet, and a set of auxiliary magnets extending about the periphery of the pole piece. Two such magnet groupings are positioned within a test chamber, separated a spacer, with the magnet groupings and the chamber defining the air gap across which the magnetic field extends. The strength and uniformity of the magnetic field is adjusted by including a second set of auxiliary permanent magnets or a set of electromagnetic shim coils positioned within the air gap surrounding and overtapping a portion of the air gap. Further adjustment of the magnetic field is accomplished shaping the front surfaces of the pole pieces, thus affecting the shape and direction of the resulting magnetic field.Type: GrantFiled: October 15, 1991Date of Patent: June 14, 1994Assignee: Advanced Techtronics, Inc.Inventors: Uri Rapoport, Richard Panosh
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Patent number: 5319339Abstract: A tubular structure having a transverse magnetic field that varies in eit the longitudinal direction or the lateral direction. In one embodiment, a permanent magnet tubular structure has a working magnetic field space that is partially bounded by pole pieces that reduce the height of the working magnetic field space. A laterally varying magnetic field is formed within the tubular structure. In another embodiment, a permanent magnet tubular structure is comprised of sections made of a permanent magnetic material, each section having a different remanence. The adjacent sections, having different remanence, form a linear array resulting in a longitudinally varying magnetic field gradient within the working space. The present invention has many practical applications such as in magnetic resonance imaging.Type: GrantFiled: March 8, 1993Date of Patent: June 7, 1994Assignee: The United States of America as represented by the Secretary of the ArmyInventor: Herbert A. Leupold
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Patent number: 5315245Abstract: A semiconductor magnetoresistive sensor and a method for its assembly is specifically provided. The preferred assembly method of this invention is compatible with automated semiconductor chip placement and packaging technology, so as to alleviate the previous requirement that the semiconductor sensing element be separately packaged. The sensor leads are substantially embedded within a powdered metal permanent magnet body. An exposed terminal end of each lead is available for electrical and adhesive contact to a subsequently attached magnetoresistive semiconductor sensing element, using conventional semiconductor placement and packaging techniques. The powdered metal magnetic body is preferably formed by utilizing powder metal compaction techniques, wherein the powder metal is compacted around the interior electrical leads.Type: GrantFiled: November 25, 1992Date of Patent: May 24, 1994Assignee: General Motors CorporationInventors: Thaddeus Schroeder, Chi H. Leung, Bruno P. B. Lequesne, Robert W. Ward
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Patent number: 5313182Abstract: Two magnetic circuits are separated by an air gap and are made up respectively of a series of permanent magnets which are attached and rigidly held together by flux return yokes. One side of the magnetic circuits is turned towards the air gap. The directions of magnetization of the opposing magnets and of the attached magnets are antiparallel and the length of each magnet is approximately two times larger than the width of the air gap.Type: GrantFiled: February 26, 1993Date of Patent: May 17, 1994Assignee: The Torrington CompanyInventor: Claire Blache
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Patent number: 5300910Abstract: In a known magnet system, specifically for magnetic separators, having homogeneously magnetized magnet blocks arranged in circular ring shape, the magnet blocks have their magnetization directions aligned differently from one to another and established in accordance with a predetermined mathematical formula. While a magnetic field running almost uniformly over the whole region of the magnet system is thus produced, the magnet blocks are made trapezoidal in cross section and, because of the many distinct magnetization directions, require separate fabrication. Both the fabrication and the assembly of these magnet blocks are therefore relatively complicated and time-consuming. In accordance with the invention, however, the fabrication and the assembly of the magnet blocks into a magnet system are quite substantially simplified and improved by virtue of the fact that the magnet blocks (1) are made square in cross section.Type: GrantFiled: December 9, 1991Date of Patent: April 5, 1994Assignee: Klockner-Humboldt-Deutz AktiengesellschaftInventors: Karl-Heinz Unkelbach, Marlene Marinescu, Nicolae Marinescu
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Patent number: 5289152Abstract: A permanent magnet magnetic circuit is provided capable of producing a unidirectional magnetic field substantially free of unnecessary perpendicular magnetic field components. A pair of main magnetic poles of opposite polarities are situated at a pair of opposite edge surfaces of a permanent magnet block for producing lines of magnetic force. One major surface of the block between the edge surfaces is provided with a channel where a pair of auxiliary magnetic poles are situated at opposed inner surface portions of the channel for controlling a middle portion of the lines of magnetic force to be linear.Type: GrantFiled: April 12, 1993Date of Patent: February 22, 1994Assignees: TDK Corporation, Kabushiki Kaisha Toshiba, Tokyo Electron LimitedInventors: Masami Oguriyama, Yoshio Ishigaki, Haruo Okano, Isahiro Hasegawa, Jun-ichi Arami, Hiromi Harada
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Patent number: 5283130Abstract: A permanent magnet is heated in a pattern by a laser beam to a localized temperature above the Curie point or a temperature sufficient to reduce the magnet coercivity sufficiently for the field of the magnet or an external field to remagnetize the pattern in the reverse direction. Magnets so produced can have very high pole density, digital encoding and analog patterns having gradually varying local field strength.Type: GrantFiled: November 6, 1991Date of Patent: February 1, 1994Assignee: General Motors CorporationInventors: John R. Bradley, Thomas A. Perry, Thaddeus Schroeder
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Patent number: 5266917Abstract: A magnet device having a predetermined field profile has an elongated permanent magnet, having a longitudinal axis and a peripheral surface, magnetized diametrically with the direction of magnetization extending transversely to the longitudinal axis and rotating about at least a portion of the length of the longitudinal axis of the magnet. The rate of rotation is selected to provide a predetermined magnetic field profile as presented to a Hall effect device positioned a fixed distance from the peripheral surface of the magnet when relative movement between the Hall effect device and the permanent magnet occurs. The magnet is formed of a composite material which includes a magnetically isotropic permanent magnet powder adhered together by an adhesive non-magnetic binder.Type: GrantFiled: November 12, 1991Date of Patent: November 30, 1993Assignee: Xolox CorporationInventors: William F. Bleeke, John M. Kaste
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Patent number: 5258735Abstract: The composite magnet of the present invention comprises two pieces of permanent magnet material formed into a complementary pattern of holes and projections. The two pieces are magnetized in opposite axial directions. The two pieces, magnetized in this manner, when placed together form an interlocking single element which exhibits a magnetic pattern of north-south poles which matches the pattern of holes and projections. In this manner, the composite magnet appears as a single permanent magnet, exhibiting a sharp, strong, and well-defined magnetic pattern. In accordance with the present invention, the composite magnet may be used in many applications including, but not limited to encoders, one of which is described in detail.Type: GrantFiled: October 28, 1991Date of Patent: November 2, 1993Inventor: Elmer C. Allwine, Jr.
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Patent number: 5252940Abstract: A magnetic material and an actuator having magnetic circuit elements incorporating the magnetic material formed of equal amounts of iron and cobalt and between about 2.1 to 5% by weight vanadium. The actuator is well suited for inclusion in an impact printer for driving the impact members of the impact printer in response to printing signals. The composition of the magnetic material of the actuator provides high energy efficiency under greatly fluctuating direct current conditions by reducing eddy currents.Type: GrantFiled: March 22, 1991Date of Patent: October 12, 1993Assignee: Seiko Epson CorporationInventor: Minoru Tanaka
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Patent number: 5243752Abstract: An instrumentation apparatus with curable internal magnets is shown. The apparatus comprises a magnetic rotor and a rotatably mountable spindle to which the magnetic rotor is attached. A support structure to which the spindle is rotatably mounted defines at least one retaining area. A material is poured into and cured in the retaining area, and then charged to form a magnet. The molded and cured magnet provides a constant magnetic field that acts upon the magnetic rotor, providing a return-to-zero function or a volt gauge function for the instrumentation apparatus.Type: GrantFiled: March 20, 1992Date of Patent: September 14, 1993Assignee: Delco Electronics CorporationInventors: Stephen M. Moore, Scott L. Semrau
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Patent number: 5237301Abstract: A magnet system such as for magnetic separators including uniformly magnetized arcuately positioned magnet blocks, the magnetization direction of the blocks being differently aligned relative to one another and defined according to a predetermined mathematical equation wherein the blocks are arranged in an arcuate path about a center and the magnetic orientation of the blocks is arranged according to the formula .psi..sub.1 =-n.phi..sub.1 in one arrangement.Type: GrantFiled: September 25, 1991Date of Patent: August 17, 1993Assignee: Kloeckner-Humboldt-Deutz AGInventors: Karl H. Unkelbach, Hans D. Wasmuth
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Patent number: 5218333Abstract: A magnetic field generating device for use with an ESR (electronic spin resonance) device essentially comprises a pair of stationary yokes and a pair of permanent magnets respectively attached to the yokes in opposite and spaced apart relationship with each other so that a magnetic field is generated in the space between the permanent magnets. A movable yoke is attached to at least one of the pair of stationary yokes so that the magnetic resistance of the magnetic path formed by the permanent magnets, stationary yokes and movable yoke is varied without changing the size of the space between the permanent magnets thereby generating a continuously changing magnetic field between the permanent magnets.Type: GrantFiled: October 2, 1989Date of Patent: June 8, 1993Assignee: Sumitomo Special Metal Co., Ltd.Inventor: Takashi Kobayashi
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Patent number: 5214404Abstract: A continuously magnetizing magnet for use in bedding for magnetic medical treatment is made of magnetic material whose semicircular crests and semicircular bases are alternately combined in series and the crests are magnetized so that they have alternately N and S magnetic poles.As the magnetic poles are isolated via the base, the magnetic lines of force are vertically generated and the magnetic density at a position upwardly far from both magnetic poles increases.Type: GrantFiled: July 31, 1991Date of Patent: May 25, 1993Assignee: Japan Life Co., Ltd.Inventors: Takayoshi Yamaguchi, Isamu Kobayashi
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Patent number: 5210493Abstract: A semiconductor magnetoresistive sensor and a method for its assembly is specifically provided. The preferred assembly method of this invention is compatible with automated semiconductor chip placement and packaging technology, so as to alleviate the previous requirement that the semiconductor sensing element be separately packaged. The sensor leads are substantially embedded within a powdered metal permanent magnet body. An exposed terminal end of each lead is available for electrical and adhesive contact to a subsequently attached magnetoresistive semiconductor sensing element, using conventional semiconductor placement and packaging techniques. The powdered metal magnetic body is preferably formed by utilizing powder metal compaction techniques, wherein the powder metal is compacted around the interior electrical leads.Type: GrantFiled: February 27, 1992Date of Patent: May 11, 1993Assignee: General Motors CorporationInventors: Thaddeus Schroeder, Chi H. Leung, Bruno P. B. Lequesne, Robert W. Ward
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Patent number: 5204572Abstract: A permanent magnet coupling including a rotatable inner member 32, and outer member 12 rotatable about the same axis 14 as the inner member 32, a plurality of magnets 36 each having a nominally trapezoidal cross section, and a plurality of interpole members 34 each having a nominally trapezoidal cross section. The interpole members 34 are disposed circumferentially between adjacent magnets 36. The major bases 38 of the magnets 36 are located on the sleeve-like cylindrically-shaped iron core 16 of the inner member 32. In operation, the side surfaces 48,50 of the permanent magnets 36 wedge between the side surfaces 42 of the interpole members 34 by centrifugal force. This, in turn, prevents the magnets 36 from moving under static or dynamic conditions. Thus, the interpole members 34 restrain the magnets 36 in a similar fashion as the containment ring 30 generally without requiring a containment ring 30.Type: GrantFiled: September 13, 1990Date of Patent: April 20, 1993Assignee: Sundstrand CorporationInventor: Caio A. Ferreira
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Patent number: H1615Abstract: A permanent magnet design including a Chiron Wiggler, which is able to produce a magnetic field to accelerate and focus electrons in a high frequency laser without the use of an externally powered, current driven solenoid.Type: GrantFiled: February 27, 1995Date of Patent: December 3, 1996Inventor: Herbert A. Leupold