Patents Assigned to Magnetic Technology, Inc.
  • Patent number: 10529362
    Abstract: A magnet structure for a magnetic data storage medium erasing apparatus includes a first half comprising a first plurality of magnets arranged symmetrically, having polarization direction of adjacent magnets in quadrature and at an oblique angle with respect to a plane of symmetry. A second half comprises a second plurality of magnets arranged symmetrically, having polarization direction of adjacent magnets in quadrature and at an oblique angle with respect to the plane of symmetry. The second half is arranged symmetrically with respect to the first half, wherein the first half and the second half are separated by an air gap disposed about the plane of symmetry.
    Type: Grant
    Filed: February 7, 2019
    Date of Patent: January 7, 2020
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventor: Chun Li
  • Patent number: 8760153
    Abstract: A rotary encoder includes a magnet disposed on a rotational axis of the encoder. The magnet is polarized transversely to the rotational axis. A first magnetic sensor is disposed on the rotational axis proximate the on-axis magnet. A magnet ring is disposed rotationally coaxially with the rotational axis and has a selected diametric distance from the axis. The magnet ring has a plurality of alternatingly polarized magnets. A number of pole pairs in the magnet ring is selected to match an angular resolution of the first magnetic sensor. A second magnetic sensor is disposed proximate the magnet ring.
    Type: Grant
    Filed: February 24, 2012
    Date of Patent: June 24, 2014
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventor: Anthony Parakka
  • Patent number: 8520333
    Abstract: A structure for erasure of magnetic media in a hard drive includes a main field pole magnet polarized in a direction toward a drive spindle motor in the hard drive. At least two quadrature magnets are disposed adjacent the main field pole magnet and polarized in a direction toward the main field pole magnet. The main field pole magnet and the at least two quadrature magnets are shaped to provide a slot for insertion of the magnetic media. At least two inverse polarity magnets are disposed on portions of the main pole and quadrature magnets forming the slot. The inverse polarity magnets are polarized in a direction opposed to the direction of the main field pole magnet.
    Type: Grant
    Filed: April 11, 2011
    Date of Patent: August 27, 2013
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventor: Chun Li
  • Patent number: 8305177
    Abstract: A magnet assembly for decoupling a plurality of different types of magnetically operated security devices includes a center pole magnet having a magnetic orientation along a first direction. A plurality of magnets adjacent to and surrounding the center pole magnet define an opening above the center pole magnet. Each adjacent magnet has a magnetic orientation orthogonal to the first direction. An end pole magnet is disposed adjacent to one of the magnets adjacent to the center pole magnet. The end pole magnet has magnetic orientation opposed to the first direction.
    Type: Grant
    Filed: January 5, 2010
    Date of Patent: November 6, 2012
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Chun Li, David Choit
  • Patent number: 7549467
    Abstract: A wellbore motor includes a source of rotational motive power disposed in a wellbore, a magnetic gear member operatively coupled at an input thereof to the source; and a magnetic gear member output coupled rotationally to a rotary wellbore tool.
    Type: Grant
    Filed: March 10, 2007
    Date of Patent: June 23, 2009
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: William J. McDonald, Timothy F. Price, Gareth P. Hatch
  • Patent number: 7487829
    Abstract: A wellbore valve includes a valve operator arranged to move axially along an interior of the wellbore, the valve operator arranged to operate a valve. A valve actuator is disposed proximate the valve operator. The valve actuator is arranged to move from one longitudinal position to another. A linear magnetic gear is coupled at an input element thereof to the valve actuator. The gear is coupled at an output element thereof to the valve operator such that motion of the valve actuator is transferred to the valve operator.
    Type: Grant
    Filed: June 14, 2007
    Date of Patent: February 10, 2009
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: William J. McDonald, Timothy F. Price
  • Patent number: 7481283
    Abstract: A wellbore motor includes a means for converting flow of fluid in the wellbore into rotational energy. A magnetic gear member is operatively coupled at an input thereof to the means for converting. A wellbore rotary tool is coupled to an output of the magnetic gear member.
    Type: Grant
    Filed: November 27, 2006
    Date of Patent: January 27, 2009
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: William J. McDonald, Timothy F. Price, Gareth P. Hatch
  • Patent number: 7373716
    Abstract: A method for constructing a permanent magnet assembly by using a non-magnetic frame between individual magnet segments to restrain the movement of the magnet segments. The frame restricts the movement of the magnets during assembly. The frame also provides an effective system for replacing magnets in the existing assembly.
    Type: Grant
    Filed: October 22, 2003
    Date of Patent: May 20, 2008
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Christopher A. Ras, Gareth Hatch, Mike Schilling
  • Patent number: 7182843
    Abstract: The magnet arrangement and resulting rotating sputtering magnetron design of an embodiment provides magnetic flux density and distribution to penetrate thick production ferrous targets. Further, the magnetic field shape improves target life by more uniformly removing target material.
    Type: Grant
    Filed: November 3, 2004
    Date of Patent: February 27, 2007
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Richard Stelter, Aron Welk, Christopher Padua, Chun Li
  • Patent number: 7135792
    Abstract: An embodiment of the invention is a particular arrangement of permanent magnets that generates a higher strength and more uniform magnetic field than existing permanent magnet arrangements for a voice coil motor. The permanent magnet arrangement of an embodiment is based on the Halbach arrangement of permanent magnets. The increased magnetic field strength and uniformity allows for a voice coil motor that is both capable of higher frequency actuations as well as more uniform force over the full stroke of the actuation.
    Type: Grant
    Filed: May 11, 2005
    Date of Patent: November 14, 2006
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Thomas J. Devaney, Chun Li
  • Patent number: 6639995
    Abstract: Disclosed is a concentric magnetic configuration for a speaker system which can produce a full range of frequency sounds from a single source magnet. The magnetic configuration of the present invention includes a high frequency pole plate and one or more middle yoke iron plate placed directly on a cylindrical permanent magnet wherein at least one magnetic flux controlling slot is formed beneath the high frequency pole plate and the middle yoke plate. The multiple air gaps defined by the pole plate and middle yoke iron produce a full range of frequency magnetic fields which can drive the high, medium, and low frequency voice coils.
    Type: Grant
    Filed: January 23, 2002
    Date of Patent: October 28, 2003
    Assignee: Advanced Magnetic Technologies, Inc.
    Inventor: You Lian Yu
  • Patent number: 6572778
    Abstract: The method includes placing a vessel containing a solution having magnetized substances into a magnetic device. The solution is then incubated in the device for a period of time sufficient to allow the magnetized substances to migrate radially toward the interior wall of the vessel, and a sample of the solution removed from the center of the vessel would contain non-magnetized particles. The magnetic device is made of four polar magnets and a plurality of interpolar magnets disposed therebetween. The interpolar magnets are positioned to progressively rotate towards the orientation of the four polar magnets creating an even flux within the solution thereby causing the radial movement of the magnetized substances toward the inner wall of the surrounding magnets.
    Type: Grant
    Filed: September 13, 2002
    Date of Patent: June 3, 2003
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Martin D. Sterman, Paul Lituri, Richard E. Stelter
  • Patent number: 6562239
    Abstract: A magnetic biological particle separation device comprising positioning a magnetic arrangement comprising a first magnet to generate a first north-south magnetic field in a plane co-planer with a horizontal cross-sectional plane of a container, positioning a second magnet in the magnetic arrangement to generate a second north-south magnetic field substantially opposing the first north-south magnetic field in a plane co-planer with the horizontal cross-sectional plane of the container, positioning a third magnet in the magnetic arrangement to generate a third north-south magnetic field substantially perpendicular to the first and the second north-south magnetic fields, directed radially away from the container, in a plane co-planer with the horizontal cross-sectional plane of the container, and pouring from the container a fluid containing magnetic beads, without a substantial loss of the magnetic beads.
    Type: Grant
    Filed: April 30, 2002
    Date of Patent: May 13, 2003
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Jeffrey E. Foy, Eric B. Sweeney
  • Patent number: 6514415
    Abstract: A method and apparatus for magnetic separation of particles within a container. In one embodiment, a container contains a number of particles and a number of magnetically susceptible particles. A number of magnets are arranged in a plane and is placed close to the container. The magnetic poles of the magnets are arranged in a pattern to apply magnetic fields oriented perpendicular to the plane on the container. The pole pattern provides in consistent separation across the container of the number of magnetically susceptible particles from the rest of the particles.
    Type: Grant
    Filed: January 30, 2001
    Date of Patent: February 4, 2003
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Gareth Hatch, Mike Schilling
  • Patent number: 6514416
    Abstract: A method and apparatus for magnetic separation of particles within a container. In one embodiment, a plurality of magnets are arranged in a first row and in a second row on a frame, wherein the plurality of magnets are oriented in a plane coplanar with a horizontal cross sectional plane of the frame. The frame has housing means between the first row and the second row for housing containers. The plurality of magnets apply north-south magnetic fields oriented coplanar with the horizontal cross sectional plane of the frame. The north-south magnetic field direction of a first magnet in the first row alternates 180 degrees from the north-south magnetic field direction of a second magnet in the first row, and the north-south magnetic field direction of a first magnet in the second row opposes the north-south magnetic field direction of the first magnet in the first row.
    Type: Grant
    Filed: May 7, 2001
    Date of Patent: February 4, 2003
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Mark A. Harradine, Richard V. Bennett
  • Patent number: 6451207
    Abstract: The magnetic pole device of the present invention has four polar magnets and any number of interpolar magnets adjacent to and in between said polar magnets. The interpolar magnets are positioned to progressively rotate towards the orientation of the four polar magnets. Such a magnetic device would create an even flux within a liquid sample and cause the radial movement of magnetized particles toward the inner wall of the surrounding magnets.
    Type: Grant
    Filed: June 4, 1997
    Date of Patent: September 17, 2002
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Martin D. Sterman, Paul Lituri, Richard E. Stelter
  • Patent number: 6413420
    Abstract: A magnetic biological particle separation device comprising a permanent magnet structure substantially surrounding a vessel containing a liquid and a biological sample in colloidal suspension in the liquid is described. The magnetic separation device comprises a window through which to view the liquid. The permanent magnet structure comprises a plurality of permanent magnets arranged in such a manner to provide for superpositioning of the external magnetic field generated by each magnet. The external magnetic field acts on magnetic beads attached to the biological sample, causing the sample to move toward the inner wall of the vessel. The permanent magnets do not completely surround the outside of the vessel to allow the liquid to be poured out of the vessel, substantially leaving the sample.
    Type: Grant
    Filed: March 17, 2000
    Date of Patent: July 2, 2002
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Jeffrey E. Foy, Eric B. Sweeney
  • Patent number: 6249200
    Abstract: A combination of magnets provides a substantially uniform external magnetic field, in which a plate shaped magnet generates an external magnetic field and a frame shaped magnet generates another external magnetic field. The frame and plate shaped magnets are disposed proximate each other to provide, through the combination of their external magnetic fields, the substantially uniform external magnetic field in a plane disposed substantially parallel to the plate and frame shaped magnets. The size, shape and relative position of the magnets combine to produce an external magnetic field having a highly uniform magnetic field orientation over a wider area of a plane disposed proximate the magnets than heretofore available.
    Type: Grant
    Filed: April 10, 1998
    Date of Patent: June 19, 2001
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Richard E. Stelter, Ging Li Wang
  • Patent number: 6084498
    Abstract: An improved magnetic decoupler with a magnetic field shape, strength and gradient optimized for releasing security tags, such as an antitheft device of the type described above. Due to the structure of the magnetic decoupler, it contains less ferrous material than prior art decouplers heretofore employed. Reduction in size of the magnetic decoupler, along with improved magnetic strength, derive from the magnet assembly including magnets arranged with orientations that increase axial magnetic field gradient by superposition of the magnetic fields of each magnet.
    Type: Grant
    Filed: April 7, 1999
    Date of Patent: July 4, 2000
    Assignee: Dexter Magnetic Technologies, Inc.
    Inventors: Richard E. Stelter, David Choit, Thomas J. Devaney
  • Patent number: 5959856
    Abstract: A dc-to-dc power converter for delivering continuous and controlled power to a load includes first and second controllable switching devices having a junction therebetween. Each of the first and second controllable switching devices include a parasitic gate to source capacitance, parasitic gate to drain capacitance, output capacitance and an intrinsic diode. First and second power supplies have a junction therebetween. A power transformer has a primary winding, a secondary winding and inductance in series with the primary winding. The secondary winding is connected to a rectifying circuit connected to the load to supply a controllable current to the load. The primary winding is connected between the junction between the first and second controllable switching devices and the junction between the first and second power supplies. A first drive circuit is connected to the first controllable switching device. A second drive circuit is connected to the second controllable switching device.
    Type: Grant
    Filed: March 9, 1998
    Date of Patent: September 28, 1999
    Assignee: Magnetic Technology, Inc.
    Inventor: Clayton L. Sturgeon