Varying Alternating Current Amplitude Responsive Patents (Class 335/231)
  • Patent number: 11659337
    Abstract: A balanced armature (BA) receiver and specifically a nickel-iron (Ni—Fe) alloy armature having improved robustness and performance receivers, as well as motors and receivers including such armatures are disclosed. The Ni—Fe armature has a nickel content of 45% or less by weight, 5% or less additive and impurities by weight, and the balance Fe. The armature can be configured as a U-reed, an E-reed or in some other configuration.
    Type: Grant
    Filed: December 29, 2021
    Date of Patent: May 23, 2023
    Assignee: Knowles Electronics, LLC
    Inventors: Charles King, Chris Monti
  • Patent number: 11197099
    Abstract: The invention discloses a screen sounding device including a frame, a screen, and a driving device. The driving device has a magnetic circuit system fixed on screen, an electromagnet driving the magnetic circuit system to vibrate and fixed on the frame and an elastic connector connecting magnetic circuit system and electromagnet. The magnetic circuit system includes a magnet arranged around the electromagnet and a magnetic frame fixing the magnet. The magnetic frame includes a top wall fixed to the screen, a bottom wall arranged opposite to top wall and a side wall connecting the top wall and the bottom wall. The magnet is fixed on a side surface of the side wall facing the electromagnet. Applying the technical solution can meet low energy consumption and provide adequate stronger driving force.
    Type: Grant
    Filed: August 13, 2020
    Date of Patent: December 7, 2021
    Assignee: AAC Technologies Pte. Ltd.
    Inventors: Lubin Mao, Zhaoxian Chen
  • Patent number: 10993035
    Abstract: A magnet system (100) for an electromechanical transducer has a first set (2) of magnets and a second set (4) of magnets. The first set (2) of magnets has a first, inner annular magnet (6) and a first outer, annular magnet (8), and the second set (4) of magnets has a second, inner annular magnet (10) and a second, outer annular magnet (12). The first, inner annular magnet (6) is arranged in the interior of the first outer annular magnet (8), and the second inner annular magnet (10) is arranged in the interior of the second outer annular magnet (12). The magnetic polarity in respect of the first, inner annular magnet (6), the first, outer annular magnet (8), the second, inner annular magnet (10), and of the second, outer annular magnet (12) has a direction (Y) corresponding to a direction perpendicular to the annular extension (X) of the magnets.
    Type: Grant
    Filed: October 4, 2019
    Date of Patent: April 27, 2021
    Assignee: Upper Level APS
    Inventor: Michael Børresen
  • Patent number: 10785573
    Abstract: A speaker device for a vehicle having a structure in which a seating direction and a magnetic path forming direction of a magnet coincide with each other, may include a frame, a magnet mounted in the frame to generate a magnetic flux, a yoke having a magnetic gap to form a magnetic path generated by the magnet, a voice coil mounted in the magnetic gap to move when a current is applied, a diaphragm engaged to the voice coil and configured to vibrate according to movement of the voice coil and generate a negative pressure, and a plate configured to support the magnet, wherein the magnet is accommodated in a horizontal direction such a seating direction and a magnetic path forming direction of the magnet coincide with each other.
    Type: Grant
    Filed: September 10, 2019
    Date of Patent: September 22, 2020
    Assignees: Hyundai Motor Company, Kia Motors Corporation
    Inventor: Youngbeom Kim
  • Patent number: 10578066
    Abstract: A valve assembly for an injection valve includes a valve body having a central longitudinal axis and a cavity with a fluid inlet portion and a fluid outlet portion, a valve needle axially movable in the cavity to prevent a fluid flow through the fluid outlet portion in a closing position and to allow fluid flow through the fluid outlet portion in further positions, and a guiding device arranged in the cavity and configured to guide the valve needle relative to the valve body. The guiding device has a first guide element fixedly coupled to the valve body and a second guide element fixedly coupled to the valve needle. The first guide element includes a magnetic material with a first magnetic field and the second guide element includes a magnetic material with a second magnetic field, the first and second magnetic fields being orientated in opposite directions.
    Type: Grant
    Filed: August 7, 2013
    Date of Patent: March 3, 2020
    Inventors: Stefano Filippi, Marco Mechi, Valerio Polidori, Mauro Grandi
  • Patent number: 10433066
    Abstract: A micro speaker includes a planar diaphragm, spacers respectively disposed at one side surface of the planar diaphragm, an upper plate and a lower plate, one or more magnets and a circuit board. The planar diaphragm includes a vibrating diaphragm and a coil conductor. The coil conductor is stretched and bonded onto the vibrating diaphragm via an adhesive layer on the upper side surface of the planar diaphragm; the coil conductor is electrically connected to the circuit board. The speaker in this present invention can get a diameter of 15 mm or less, and a height is 5 mm or less.
    Type: Grant
    Filed: October 11, 2018
    Date of Patent: October 1, 2019
    Inventor: Hong Xue
  • Patent number: 10162390
    Abstract: The described embodiments relate to an electronic assembly that includes multiple varied electrical components. In some embodiments, the electronic assembly can include electrical components susceptible to electromagnetic interference (EMI). In one particular embodiment, an antenna can be positioned along an exterior surface of an enclosure of the electronic assembly and another electrical component can be disposed within the enclosure. When the other electrical component is a speaker component, a port or opening for emitting audio output can be protected from EMI by surrounding the port with a conductive gasket that includes a closed cell foam substrate wrapped in an electrically conductive fabric. In some embodiments, the closed cell foam substrate defines a number of perforations that are plated with an electrically conductive material.
    Type: Grant
    Filed: January 15, 2016
    Date of Patent: December 25, 2018
    Assignee: Apple Inc.
    Inventors: Edward T. Sweet, Jerzy S. Guterman, Houtan R. Farahani, Justin D. Crosby, Daniel K. Boothe
  • Patent number: 9601980
    Abstract: An electromechanical transducer of the invention comprises a structural unit, an armature, and two elastic units. The structural unit includes magnets, a yoke and a coil. The armature has an inner portion disposed to pass through inside the structural unit and two outer portions protruding from the inner portion, and the armature constitutes a magnetic circuit with the structural unit via two regions through which components of the magnetic flux flow in reverse directions in the inner region. The elastic units give restoring forces to the outer portions in response to displacement of the armature due to magnetic forces of the magnetic circuit. Each of the elastic units includes a pair of elastic members symmetrically arranged via the armature in a direction of the displacement. Each of the elastic members has one end engaging one of the outer portions and another end engaging one of the elastic member attaching portions.
    Type: Grant
    Filed: February 4, 2014
    Date of Patent: March 21, 2017
    Assignee: RION CO., LTD.
    Inventors: Takashi Iwakura, Fumitaka Funahashi
  • Patent number: 9485584
    Abstract: An apparatus related to a magnetic circuit design is disclosed. The apparatus includes a magnetic assembly and an electrically-conductive mobile member. The magnetic assembly includes an inner magnet, an outer magnet, an inner cap, an outer cap and a washer. The magnetic assembly is configured to produce a magnetic field having a zone of operation between the inner cap and the outer cap. The zone of operation has substantially uniform magnetic field strength. The zone of operation has magnetic field directions substantially perpendicular to an ideal motion direction. The electrically-conductive mobile member is disposed in the zone of operation of the magnetic field and electrically coupled to a diaphragm of a driver. The electrically-conductive mobile member is configured to move within the zone of operation of the magnetic field in response to the magnetic field when an alternating current is passed through the electrically-conductive mobile member.
    Type: Grant
    Filed: March 13, 2014
    Date of Patent: November 1, 2016
    Assignee: Skullcandy, Inc.
    Inventor: Rex Price
  • Patent number: 9301054
    Abstract: An electromechanical transducer of the invention comprises a structural unit, an armature, and first and second elastic members. The structural unit includes at least one pair of magnets, a yoke conducting a magnetic flux generated by the magnets, and a coil supplied with an electric signal. The armature has an inner portion disposed to pass through an internal space of the structural unit and first and second outer portions protruding on both sides from the inner portion, and the armature constitutes a magnetic circuit with the structural unit via two regions through which components of the magnetic flux flow in directions opposite to each other in the inner portion. The first and second elastic members connect between the first and second outer portions of the armature and the structural unit, respectively.
    Type: Grant
    Filed: January 29, 2014
    Date of Patent: March 29, 2016
    Assignee: RION CO., LTD.
    Inventors: Takashi Iwakura, Munehiro Date
  • Patent number: 9154884
    Abstract: An electro-acoustic transducer includes a frame, a magnet circuit unit accommodated in the frame, and a vibration unit engaging with the frame. The magnetic circuit unit includes a lower plate, a main magnet positioned centrally on the lower plate, a pair of auxiliary magnets positioned spaced from the main magnet for forming a magnetic gap, and a pair of upper plates attached to the auxiliary magnets, respectively. Each upper plate includes a base body integrated with the frame, and a restricting part extending from the base body and engaging with an inner surface of the auxiliary magnet facing the main magnet.
    Type: Grant
    Filed: July 30, 2014
    Date of Patent: October 6, 2015
    Assignee: AAC Technologies Pte. Ltd.
    Inventor: Xudong Yan
  • Patent number: 7660083
    Abstract: An electromechanical/solid-state AC relay has an electromechanical winding coil that moves an armature to force mechanical contacts to open or close. Electrical arcing across the mechanical contacts that occur as the contacts are opening or closing can damage and severely reduce the lifetime of the relay. Contact arcing is prevented by pulsing a triac on for a short period of time just before and after the mechanical contacts make or break contact. The triac limits the voltage difference across the mechanical contacts to less than one volt to prevent arcing. The triac is turned off after the mechanical contacts finish moving, reducing the heating and average power through the triac. A zero-sampling circuit that detects when the AC input voltage switches across 0 volts and activates a control integrated circuit to switch on the triac during zero-crossings to minimize power surges.
    Type: Grant
    Filed: August 6, 2007
    Date of Patent: February 9, 2010
    Assignee: Pericom Technology Inc.
    Inventors: Li Yao, Shu Peng Chen, Yong Wei
  • Patent number: 7518479
    Abstract: An inline electromagnetic tool actuator incorporates an actuator housing, an elongated armature, a tool assembly, spaced-apart return magnets, at least one drive magnet, and at least one magnet wire. The elongated armature is located inside the housing, and is adapted for reciprocating linear movement along a notional assembly axis. The tool assembly is operatively attached to the armature. The return magnets are located inside the housing, and are coaxially aligned with the armature. The return magnets have respective inward facing surfaces defining respective magnetic poles. The drive magnet is affixed to the armature, and is arranged between the return magnets. The drive magnet has opposing outward facing surfaces each of like polarity to adjacent inward facing surfaces of the return magnets. The magnet wire is coiled about the armature.
    Type: Grant
    Filed: August 31, 2006
    Date of Patent: April 14, 2009
    Inventors: Thomas Mask, Mark Evans
  • Publication number: 20090091410
    Abstract: A magnetic levitation vibration system comprising a top plate, a base plate, at least one first magnet, at least one second magnet, at least one electromagnetic actuator comprising an upper half and a lower half, a controller, a sensor, and a control circuit. A method for the treatment or prevention of musculoskeletal indications comprising providing a top plate, providing a base plate, generating a first magnetic field to levitate the top plate, generating a second magnetic field to drive the top plate into vibration, adjusting frequency of vibration of the top plate; and adjusting magnitude of vibration of the top plate.
    Type: Application
    Filed: October 5, 2007
    Publication date: April 9, 2009
    Applicant: The Chinese University of Hong Kong
    Inventors: Kwok-Sui Leung, Wing-Hoi Cheung, Kam-Fai Tam, Wai-Kin NG
  • Publication number: 20080309440
    Abstract: An electroacoustic transducer has a magnetic circuit unit including a plate-shaped yoke, first and second magnets juxtaposed on the yoke, and first and second top plates mounted on the respective tops of the first and second magnets. One end of the first magnet is magnetized to one of north and south poles. The other end of the first magnet is opposite in polarity to the one end. The second magnet is magnetized to polarities opposite to those of the first magnet. A magnetic gap is formed between the first and second top plates.
    Type: Application
    Filed: June 13, 2008
    Publication date: December 18, 2008
    Inventor: Toshio Itakura
  • Patent number: 7260229
    Abstract: The invention relates to an improved electro-dynamic loudspeaker.
    Type: Grant
    Filed: October 16, 2002
    Date of Patent: August 21, 2007
    Assignee: Audio Products International Corp.
    Inventor: Stefan R. Hlibowicki
  • Patent number: 6020805
    Abstract: A permanent magnet assembly comprising an essentially tubular magnet element which is radially magnetized, inner and outer members of a magnetic material resting against inner and outer sides, respectively, of the magnet element, and an annular top plate placed on one end of the outer member. The annular top plate and an end portion of the inner member form an annular air gap which is axially separated from the magnet element and across which the magnetic flux of the magnet element extends radially. The inner member has a polygonal outer surface. The magnet element is divided axially into a number of separate magnet segments having inner surfaces fixed to corresponding outer surfaces of the inner member.
    Type: Grant
    Filed: December 1, 1998
    Date of Patent: February 1, 2000
    Assignee: Seas Fabrikker As
    Inventor: Bj.o slashed.rn B.o slashed.rja
  • Patent number: 5896076
    Abstract: An electromagnetic active vibration actuator configuration combines two modes of operation to obtain the advantages of long stroke and linearity of voice coil type actuators and high efficiency of dual-gap solenoid type actuators. A coaxial stator shell surrounds an axially vibratable armature. Either the stator or the armature can carry one or more coils and/or permanent magnets, however usually the magnets are located on the armature for their contribution to vibrating mass. Alternate coils and alternate magnets are made opposite in polarity, the stator armature pole pieces being held symmetrically staggered relative to the stator pole pieces by end springs or flexures that allow axial vibration when AC is applied to the coils.
    Type: Grant
    Filed: December 29, 1997
    Date of Patent: April 20, 1999
    Inventor: Frederik T. van Namen
  • Patent number: 5883557
    Abstract: A magnetically latching solenoid apparatus is characterized by a non-magnetic armature carrying a permanent magnet having poles aligned with the throw axis of the device. The poles of the magnet are substantially aligned with corresponding pole pieces and define respective variable air gaps therebetween. The apparatus assumes one of two bistable magnetically latched states according to the one of the air gaps across which the magnetic attractive force exceeds the magnetic attractive force across the other of the air gaps. Single or dual winding coils temporally excitable unidirectionally or bidirectionally and, in the case of dual winding coils mutually exclusively or contemporaneously, to cause the latch state to change.
    Type: Grant
    Filed: October 31, 1997
    Date of Patent: March 16, 1999
    Assignee: General Motors Corporation
    Inventors: Andrzej Marian Pawlak, Chi Hung Leung
  • Patent number: 5705969
    Abstract: An actuator for converting electrical energy into rotary or reciprocating motion comprising a casing filled with an electro-sensitive fluid, the casing having a plurality of electrodes affixed along its inner periphery and including a rotary member which is impelled by the flow of the electro-sensitive fluid when DC voltage is applied to the electrodes.
    Type: Grant
    Filed: July 26, 1995
    Date of Patent: January 6, 1998
    Assignee: Fujikura Kasei Co., Ltd.
    Inventors: Kazuya Edamura, Yasufumi Otsubo
  • Patent number: 5367277
    Abstract: An electromagnetic energy converter comprises a frame-like magnet core, a closed magnetic path being formed along the sides of the magnetic core, a winding wound around the magnet core and connected to a power supply or a load, an armature conductor having a frame-like body forming a closed electric circuit and having a portion of the magnet core passed therethrough, and a field magnet disposed so that the magnetic flux generated thereby passes through the magnet core and armature conductor. One of the winding, armature conductor and field magnet is movable with respect to the magnet core. Electric power is transmitted between the winding and armature conductor by electromagnetic induction, and conversion of electromagnetic energy takes place between the magnetic flux generated by the field magnet and the armature conductor through the displacement of the movable part.
    Type: Grant
    Filed: July 24, 1992
    Date of Patent: November 22, 1994
    Assignee: Nippon Steel Corporation
    Inventor: Chikara Kaidou
  • Patent number: 5323133
    Abstract: A device for making electrical connection to a reciprocating element, such as to a voice coil of an actuator. An electrical flow path utilizing the helical centering springs as a primary element in conducting current ensures reliable current flow to a reciprocating element and avoids high-speed flexing of brittle wires. Hard-wired connections are utilized only between stationary elements. A second double-coil actuator embodiment employs a coaxial, substantially co-extensive pair of springs as the input and return current flow paths for each actuator.
    Type: Grant
    Filed: July 15, 1992
    Date of Patent: June 21, 1994
    Assignee: Lord Corporation
    Inventors: Michael C. Heath, John J. Quinn
  • Patent number: 5315471
    Abstract: The coil holding current of a contactor is regulated to the lesser of two measurements of coil current during each cycle of the full-wave rectified control voltage to compensate for induced flux in the coil generated by load current through the main contacts of the contactor, thereby preventing uncontrolled drop out of the contactor.
    Type: Grant
    Filed: June 1, 1992
    Date of Patent: May 24, 1994
    Assignee: Westinghouse Electric Corp.
    Inventors: Rick A. Hurley, Mark E. Innes
  • Patent number: 5270676
    Abstract: A lower die having a first recess corresponding to one of outer shapes of the element, and an upper die having a second recess are provided. The outer diameter of the upper dies is smaller than the inner diameter of the first recess so that a gap is formed between the inside wall of the first recess and the outside wall of the upper die. A workpiece is put between the lower and upper dies, and the upper die is pressed against the lower die to form the element.
    Type: Grant
    Filed: December 20, 1991
    Date of Patent: December 14, 1993
    Assignee: Pioneer Electronic Corporation
    Inventors: Kunio Mitobe, Shuichi Watanabe, Masatoshi Sato
  • Patent number: 5128825
    Abstract: A microprocessor controlled electrical contactor monitors the voltage and peak current produced by a first voltage pulse gated to the coil of the contactor electromagnet and adjusts the conduction angle of the second pulse to deliver a constant amount of electrical energy to the electromagnet coil despite variations in coil resistance and supply voltage so that the contactor contacts can be consistently closed with low impact velocity and minimum contact bounce. Normally, the third and subsequent pulses are gated to the coil at constant conduction angles selected so that the contacts consistently touch and seal on a preselected pulse with declining coil current. Under marginal conditions, determined by the peak current produced by the first pulse, the third and subsequent pulses are gated at substantially full conduction angles to assure contact closure. If the voltage or current produced by the first pulse is below a predetermined value, closure is aborted.
    Type: Grant
    Filed: February 1, 1990
    Date of Patent: July 7, 1992
    Assignee: Westinghouse Electric Corp.
    Inventors: Rick A. Hurley, Bruce R. Quayle
  • Patent number: 4846715
    Abstract: A voice coil motor assembly for a voice coil motor printwheel setting apparatus comprises a plate having the voice coil motor coils mounted thereon. The plate is adapted for attachment to a printed circuit board by pins electrically connected to the voice coils. Picker links having voice coil magnets connected thereto are stacked in sequence and the final assembly is completed by enshrouding the voice coil magnets with the voice coils mounted on the plate.
    Type: Grant
    Filed: December 21, 1987
    Date of Patent: July 11, 1989
    Assignee: Pitney Bowes Inc.
    Inventors: Donatas V. Gasiunas, Paul R. Sette, Anthony Storace
  • Patent number: 4720763
    Abstract: An electromagnetic contactor or controller is taught in which the voltage which is impressed across the electromagnetic armature accelerating coil is compared by a microprocess against a menu of memory stored voltages with related delay angles. The delay angles are utilized to alter the conduction interval of a triac or similar gated device which is connected in series circuit relationship with the coil in question. During an ACCELERATION interval a number of consecutive full-wave rectified half-cycles of voltage pulses are phase angle or delay angle controlled so that the amount of energy provided to the moving armature of the contactor is approximately sufficient to cause the armature to abut a fixed magnetic member. Furthermore, there is provided a separate memory menu for mid-flight adjustment of the armature to compensate for unknown variations to fine tune the closing operation. This latter correction is known as COAST.
    Type: Grant
    Filed: February 19, 1987
    Date of Patent: January 19, 1988
    Assignee: Westinghouse Electric Corp.
    Inventor: James A. Bauer
  • Patent number: 4720761
    Abstract: An electromagnetic contactor is taught which includes a conduction angle controlled triac or similar gated device which is connected in series circuit relationship with the winding of an electromagnetic solenoid or coil which is responsible for closing the contactor contacts and for keeping them closed. The current flowing through the triac is fed to a microprocessor which digitizes the current and compares it to a stored standard. The conduction angle is then decremented or incremented as necessary to change the conduction angle to cause less or more current to flow per half cycle until the amount of current flowing as sensed on a half-cycle-by-half-cycle basis is equal to the current represented by the stored standard.
    Type: Grant
    Filed: February 19, 1987
    Date of Patent: January 19, 1988
    Assignee: Westinghouse Electric Corp.
    Inventors: Gary F. Saletta, Joseph C. Engel, John G. Leddy
  • Patent number: 4628154
    Abstract: An annular gap magnet system, in particular for a low frequency loudspeaker (Woofer), in which a coil is movable with a large stroke in the working air gap. A braking air gap provided in the region of the inner or lower pole plate produces a magnetic resistance in the pole plate so that a part of the magnetic flux flows over the braking air gap. This magnetic flux is opposed to the stray magnetic flux below the working air gap and excites a counter magnetic field which opposes further inward movement of the moving coil. In this way an impact of the moving coil against the inner or lower pole plate is prevented. In a low frequency loudspeaker the membrane carrying the moving coil may, therefore, be suspended extremely softly.
    Type: Grant
    Filed: December 23, 1982
    Date of Patent: December 9, 1986
    Inventor: Eckehard K. Kort
  • Patent number: 4580119
    Abstract: Mono-directional magnetic anisotropy given to a Fe-Cr-Co straight tube by initial heat magnetization is converted into radial magnetic anisotropy by subsequent formation of one or more flange sections through plastic deformation which is perpetuated by final age-hardening in order to obtain an excellent configuration magnet well suited for electro-acoustic converters.
    Type: Grant
    Filed: May 23, 1983
    Date of Patent: April 1, 1986
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventors: Kenzaburo Iijima, Toshiharu Hoshi, Kazumoto Asano, Yoshinori Hayashi
  • Patent number: 4465906
    Abstract: A low-leakage pot magnet system for moving-coil loudspeakers having two permanent magnets of opposite polarity is accomplished by spacing the lower permanent magnet away from the bottom of the screen pot by an appropriate support which includes a disk or plate of nonmagnetic material arranged between the lower permanent magnet body and the bottom of the screen pot.
    Type: Grant
    Filed: September 28, 1982
    Date of Patent: August 14, 1984
    Assignee: Magnetfabrik Bonn GmbH Vormals Gewerkschaft Windhorst
    Inventors: Kurt Adolph, Winfried Grimbach
  • Patent number: 4427958
    Abstract: An acoustic transducer of novel structure suitable for automatic assembly is made by arranging with its wall upwards a generally cup-shaped rear cover having a cylindrical wall out-turned at its upper end and extending from the rim of a base divided along a chord into a major segment for receiving an electromagnetic driving unit and a terminal receiving minor segment at a higher vertical level than the major segment. The major segment has on its inner face fixing lands disposed symmetrically with respect to a diameter normal to said chord offset away from the minor segment and extending inwards from the side wall. Each fixing land is formed to define a fixing location and having on its face presented to the minor segment an upstanding locator wall.
    Type: Grant
    Filed: September 14, 1982
    Date of Patent: January 24, 1984
    Assignee: A. P. Besson Limited
    Inventors: David V. Charlesworth, Derek F. Smith
  • Patent number: 4425482
    Abstract: The disclosure relates to a ring armature electroacoustic transducer adapted for use as the receiver for telephone sets and for other purposes. The exemplary embodiment comprises the following elements coaxial about a common vertical axis: (a) a cylindrical ring permanent magnet (15) of Fe-Cr-Co material, (b) an annular disc upper pole piece (20) seated on magnet 15 and having at its inner margin a downwardly salient annular boss (30) providing an upper pole tip, (c) a lower pole piece (35) providing an annular lower pole tip (37) and aflange (36) coupling such tip (37) to the bottom of the magnet, (d) an armature support (40) within the magnet (15), (e) an annular disc armature (50) seated on the support (40), (f) a diaphragm (60) on the armature (50), and (g) a terminal plate (45) supporting such elements. The armature (50) is seated on a circular edge (90) on the support (40). The support (40), lower pole piece (35) and plate (45) form a unitary structure.
    Type: Grant
    Filed: March 8, 1982
    Date of Patent: January 10, 1984
    Assignee: Western Electric Company
    Inventors: Chester M. Bordelon, Richard M. Hunt, Robert A. Wheeler
  • Patent number: 4386332
    Abstract: A magnetic circuit for a dynamic speaker which can be manufactured inexpensively without the need of machining. The magnetic circuit includes an annularly-shaped magnet, a pole yoke having a backplate coupled to a first surface of the magnet and a pole yoke extending from a central portion of the back plate through a hole in the annularly-shaped magnet, and an annular top plate coupled to a second surface of the magnet with an air gap being formed between the top plate and the center pole. A tapered groove is formed in the back plate along a circumferential direction of the base of the center pole tapering outwardly toward the magnet. The groove extends beyond a region defined by the inner diameter of the magnet.
    Type: Grant
    Filed: July 31, 1981
    Date of Patent: May 31, 1983
    Assignee: Pioneer Electronic Corporation
    Inventor: Tatsuo Saito
  • Patent number: 4346318
    Abstract: Apparatus for producing linear motion comprising a coil defining an electromagnetic field across a gap; and a permanent magnet disposed within the magnetic field in the gap and arranged to be driven in motion by the magnetic field, the permanent magnet being configured such that its axis of magnetization lies along its smallest dimension.
    Type: Grant
    Filed: February 21, 1979
    Date of Patent: August 24, 1982
    Assignee: Yeda Research and Development Co. Ltd.
    Inventor: Shmuel Shtrikman
  • Patent number: 4293741
    Abstract: A loudspeaker design for use in transmitting and receiving sound waves is disclosed. The loudspeaker consists of a basket (12) and magnet assembly (14). The magnet assembly consists of a sandwich of front (16) and back (20) plates on either side of a ring-shaped ceramic magnet (18). The back plate (20) has a pole piece (22) projecting outward therefrom. The ceramic magnet (18) has a center aperture. The magnet (18) is affixed to back plate (20) concentrically around the projecting pole (22). The front plate (16) is circular in shape and also has a center aperture (31). A centering device and shield (24) is placed concentrically around the projecting pole (22) and is adjacent to the inside surface of the back plate (20), the inner surface of the aperture (30) within the ceramic magnet (18), and the inner surface of front plate (16) when it is affixed to the ceramic magnet, thereby creating the above-mentioned sandwich.
    Type: Grant
    Filed: June 21, 1979
    Date of Patent: October 6, 1981
    Inventor: Clifford B. Digre
  • Patent number: 4289937
    Abstract: A speaker comprises a voice coil placed in an air gap between a center pole and a plate wherein a specific ferromagnetic material obtained by forming fine crystalline grains is used on at least one of the surfaces of the center pole and the plate which respectively face the voice coil, thereby providing a speaker having low distortion.
    Type: Grant
    Filed: May 10, 1979
    Date of Patent: September 15, 1981
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hideo Ikeda, Hideshi Tsuchiya, Masaru Okada
  • Patent number: 4163962
    Abstract: The subject matter of the present invention is a universal impedance element of electric power transmission and distribution use, having either fixed or controllably variable magnitude. One and the same unit of such element can be made to function as an inductor, condenser, contactless voltage regulator, fault-current attenuator, or arcless circuit breaker, by either choosing the magnitude of one mechanical and/or one electrical parameter.
    Type: Grant
    Filed: February 17, 1977
    Date of Patent: August 7, 1979
    Inventor: Nick D. Diamantides
  • Patent number: 4035591
    Abstract: An electroacoustic transducer includes a permanent annular magnet with a central aperture, with front and back multisided flux plates attached to the annular magnet to complete a magnetic circuit which drives a voice coil and operatively drives a diaphragm. The edges of the front and back multisided fluxed plates defined a surface area of approximately 77 percent of the area bounded by the outer diameter of annular magnet.
    Type: Grant
    Filed: March 12, 1976
    Date of Patent: July 12, 1977
    Assignee: Carbonneau Industries, Inc.
    Inventor: Gordon S. Carbonneau
  • Patent number: 4015227
    Abstract: An electromagnetic transducer in which a D.C. magnetic flux generating section including a permanent magnet and a signal flux generating section including a coil are arranged in spaced relation on opposite sides of a diaphragm to form a balanced type transducer.
    Type: Grant
    Filed: February 25, 1975
    Date of Patent: March 29, 1977
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasuhiro Riko, Kenzo Miura
  • Patent number: 3971054
    Abstract: The permanent magnet of a magnetic structure is formed of isotropic magnetic material, and is magnetized along the path that the flux follows during use of the magnetic structure to increase the efficiency of the magnetic structure in use. The magnetic structure, which may be the annular magnetic structure of an electrodynamic loudspeaker, includes a cylindrical permanent magnet and an annular cup-like return path element connected to the magnet at one end thereof and forming an air gap with the magnet at the opposite end. Apparatus is provided for magnetizing the permanent magnet having an annular portion which may extend into the air gap of the speaker magnetic structure, to provide curved magnetic lines in the permanent magnet in substantially the path of the operating flux to the air gap.
    Type: Grant
    Filed: July 12, 1974
    Date of Patent: July 20, 1976
    Assignee: Motorola, Inc.
    Inventor: Leon Jasinski
  • Patent number: 3937904
    Abstract: A transducer device such as a loudspeaker or microphone has a U-shaped core of magnetically permeable material with attached pole pieces defining a gap and a stationary electrical coil around the core. A permanent magnet is positioned for movement through the central portion of the gap as directed by a variable magnetic field within the gap. The permanent magnet has diagonally positioned poles of like magnetic orientation to provide a north-south pole combination facing one of the pole pieces and a complementary south-north pole combination facing the other pole piece.
    Type: Grant
    Filed: August 7, 1974
    Date of Patent: February 10, 1976
    Assignee: Hitachi Magnetics Corporation
    Inventor: Rollin James Parker