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US2511114A - Polarized electromagnet - Google Patents

Polarized electromagnet Download PDF

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Publication number
US2511114A
US2511114A US752889A US75288947A US2511114A US 2511114 A US2511114 A US 2511114A US 752889 A US752889 A US 752889A US 75288947 A US75288947 A US 75288947A US 2511114 A US2511114 A US 2511114A
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US
United States
Prior art keywords
armature
pole
magnetic
magnets
faces
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US752889A
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English (en)
Inventor
Grant G Lavery
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to FR963909D priority Critical patent/FR963909A/fr
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US752889A priority patent/US2511114A/en
Priority to GB15120/48A priority patent/GB660997A/en
Application granted granted Critical
Publication of US2511114A publication Critical patent/US2511114A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R11/00—Transducers of moving-armature or moving-core type

Definitions

  • This invention relates to electromagnetic translating devices and more particularly to armature type electromagnetic units especially suitable for use in telephone receivers and transmitters.
  • One known type of electroacoustic transducer comprises, generally, a magnetic armature fixed at one end and having its other end extending into a gap between a pair of pole pieces between which a direct current flux is maintained by one or more permanent magnets.
  • a signal coil is associated with the magnetic circuit including the armature for varying the flux in the circuit thereby to cause vibrations of the armature in accordance with signal currents supplied to the coil or, conversely, for establishing a signaling current in accordance with vibrations of the armature.
  • One object of this invention is to simplify the construction and to facilitate the manufacture of electroacoustic transducers of the general type above described.
  • Another object of this invention is to expedite the attainment of substantially exact magnetic balance of the armature in the absence of signaling currents in the signal coil.
  • a further object of this invention is to increase the magnetic and operating eillciencies of armature type electromagnetic translating devices.
  • the elements including the armature, pole pieces and magnets, of the magnetic system are constructed and arranged so that when the elements are assembled in pile-up relation the free end of the armature is substantially centered automatically in the gap between juxtaposed faces of the pole pieces and preassigned magnetic gaps between the armature and these faces obtain.
  • the magnetic system comprises a pair of longitudinally magnetized, bar permanent magnets mounted in alignment, with the juxtaposed pole faces thereof of unlike polarity, a pair of pole pieces each seated upon the other pole face of a respective magnet and having a pole tip coplanar with the respective one of the juxtaposed pole faces, an armature having one end portion extending between the pole tips and another portion extending between the juxtaposed pole faces, and magnetic shims interposed between and spacingthe armature from the juxtaposed magnet pole faces.
  • the shims are of equal preassigned thickness so that when the elements are assembled in pile- 2 length obtain between the of the pole pieces.
  • the magnets are provided with grooves in the juxtaposed pole faces to permit the insertion of a tool therethrough in the assembled structure, for effecting bending of the armature adjacent the magnets thereby to adjust the armature-pole piece spacings if necessary or desired.
  • the armature is provided with one or more extensions, for example tabs extending from the fixed portion thereof, in juxtaposition to the magnets, these extensions constituting magnetic shunts across the magnet or magnets and being adjustable relative to the latter to compensate for magnetic unbalances in the magnetic system.
  • the armature is formed of two portions having different magnetic characteristics, to enhance the magnetic and. hence, the operating eiliciency of the device. More specifically, in accordance with this feature of the invention, the portion of the armature extending between the juxtaposed faces of the magnets is constructed of a material having a higher reversible permeability at low flux densities and lower coercive force than the part of the armature which extends between the tips of the pole pieces.
  • Fig. 1 is a side elevational view in section of an electroacoustic transducer illustrative of one embodiment of this invention
  • Fig. 2' is an exploded perspective view of the magnetic unit included in the transducer illustrated in Fig. l;
  • Fig. 3 is a diagram illustrating the magnetic circuit included in the transducer shown in Fig. 1.
  • the electromagnetic device therein illustrated is operable as either a telephone receiver or transmitter and comprises a pair of substantially identical bar or block magnets IDA and MB, advantageously of a high coercive force magnetic material such as an aluminum-nickel-cobalt-iron alloy known comarmature and the tips flashally as Alnico.
  • the magnets are posiup relation, equal magnetic gap of prescribed tioned in alignment with each other,
  • each magnet has afllxed thereto, as by soldering, an L-shaped pole piece II having a flange l2 terminating in a pole tip face I3, the pole pieces being 'of high permeability material.
  • a nickel-iron alloy known commercially as Permalloy.
  • each pole piece is affixed to the respective magnet and the pole tip face and respective magnet face are made accurately coplanar, as by grinding or lappin thereof.
  • One of the pole pieces may be formed as an integral part of a foundation plate I4, the function of which will appear presently.
  • a rectangular armature ISA. ISB extends between the pole tip faces I3 and the magnets In and is spaced from the latter by substantially identical, high permeability, e. g. Permalloy," shims I6. These shims are made of preassigned thickness, for example .004 inch, so that, inasmuch as the pole tip faces and the respective magnet faces are coplanar, the armature to pole tip face spacings are equal and-fixed at a desired value by the shims.
  • Thefmag'nets I0, pole pieces II, armature IS and shims IS are assembled in pile-up relation and are fixedly clamped together as by a pair of screws I'l extending between the pole pieces and threaded into one of them.
  • a signal coil II is mounted between the pole pieces II and encompasses the armature IS.
  • the plate I4 serves as a mount for a circular, non-magnetic diaphragm I9 which, together with annular washers 20, may be secured to the plate by an annular clamping band 2 I.
  • the diaphragm I9 is coupled at its center to the free end of the armature IS by a connecting link or drive rod 22.
  • M1 and M2 are the magnetomotive forces of the two magnets, R1 and R: are the reluctances of the by to exactly center the armature in the gap between the pole tip faces I3.
  • the armature IS is provided with integral extensions or tabs 24 adjacent the magnets.
  • These tabs represented by S1 and S: in Fig. 3, constitute adjustable shunts across the magnets. Adjustment is effected by bending the tabs to increase or decrease the spacing thereof from the magnets to establish exact equality of the two arms, R1, M1, Si and R2, M2, 82, of the magnetic bridge circuit. Adjustment of these tabs is equivalent to a vernier mechanical adJustment of the position of the armature in the two air gaps.
  • the air gaps may be equalized and the two arms, above-noted, of the magnetic circuit also may be equalized, whereby both mechanical and magnetic balance of the system are attained and, therefore, high efliciency and faithful translation of signals are realized.
  • the magnetic and, hence, the operating efllciency of the transducer is dependent upon the magnetic character of the armature IS particularly upon its reversible permeability, which is one aspect of its magnetic character.
  • the tractive force on the armature is a positive function of its reversible permeability, which is therefore a measme of the displacement response of the armature to variations in that force.
  • substantially optimum magnetic characteristics for the armature are realized. specifically. as illustrated clearly in Fig. 2, the armature I5 is constructed of two sections ISA and ISB joined and to end, as by butt weld ing.
  • the two sections are of different magnetic materials, the section ISB having a higher reversibl permeability at low flux densities and lower coercive force than the portion or section ISA, whi n has a higher reversible permeability at high iux densities than the portion ISB,
  • the portion or section ISA may be of 45% Permalloy (45% nickel and balance iron) and the portion or section ISB may be molypermalloy (4% molybdenum, 79% nickel and balance iron).
  • the latter portion is at a low superimposed flux density in the operation of the device,- being adjacent the neutralpoint of the two permanent magnets and having a largereffective area which the flux traverses than the portion ISA adjacent the small pole tip areas. Because of the low coercive forc of the portion ISB, positional variations of the armature due to residual flux in th armature following mechanical or magnetic displacement of the armature are reduced whereby the stability of the magnetic unit is increased. Additionally, the possibility of the armature freezing to one of the pole tip faces is minimized, whereby very short air tip faces. The reluctances of the pole pieces are so small, usually, as to be negligible. In order that magnetic balance may exist, it is obvious that the parameters involved in the system must be such that the flux through the armature be zero.
  • G1 and G2 should be exactly equal.
  • This desideratum is obtainable readily in devices constructed in accordance with a feature of this invention.
  • the juxtaposed pole faces of the two magnets are provided with parallel grooves 23 through which a tool may be inserted to effect a permanent bending of the armature adjacent the magnets theregaps between th armature and the pole tip faces cs tion has been shown and described, it will be understood that it is but illustrative and that variface of unlike polarity of the other magnnet, a pair of pole pieces each extending from the other pole face of a respective magnet and having a pole tip face coplanar with the respective one of the juxtaposed pole faces, the pole tip faces defining a ap, a unitary magnetic sheet metal armature assembly having an integral armature with one portion in said gap and another portion clamped between said juxtaposed pole faces, a signal coil in electromagnetic relation with said armature, and a pair of spacer members each inter
  • An electromagnetic translating device comprising a pair of substantially equal permanent magnets positioned in alignment and magnetized in the direction of their alignment, one pol face of one magnet being in juxtaposition to the pole face of unlike polarity of the other magnet, a pair of pole pieces each extending from the other pole face of a respective magnet and having a pole tip face coplanar with the respective one of the juxtaposed pole faces, the pole tip faces defining a gap, a unitary magnetic sheet metal armature assembly clamped between the magnets comprising an integral armature having one portion in said gap, another portion between said juxtaposed pole faces and magnetic shunt means comprising an element extending substantially perpendicular to said armature along each of the two magnets away from the other magnet, a signal coil in electromagnetic coupling relation with said armature, and a pair of spacer members each interposed between said another portion of said armature and one of said pole faces.
  • An electromagnetic translating device comprising a pair of aligned, juxtaposed, block permanent magnets magnetized in the direction of their alignment and having their juxtaposed pole faces of unlike polarity, a pair of pole pieces having pole tip portions spaced to define a gap, each of said pole pieces extending from the other pole face of a respective magnet, a unitary magnetic sheet metal armature assembly comprising an armature having on end portion in said gap and an intermediate portion clamped between said juxtaposed pole faces, said one end portion being of a material having a higher reversible permeability at high fiux densities than the material of said intermediate portion and said intermediate portion being of material having a higher reversible permeability at low flux densities than the material of said on portion, and a signal coil in electromagnetic coupling relation with said armature, said armatur assembly also comprising two integral magnetic shunt elements separately extending from between said magnets with each shunt element extending along a different one of the two magnets away from the other magnet to a point of substantially different magnetic
  • An electromagnetic translating device comprising a pair of aligned, juxtaposed, block permanent magnets magnetized in the direction of their alignment and having their juxtaposed faces of unlike polarity, a pair of pole pieces having pole tip portions spaced to defin a gap, each of said pole pieces extending from the other pole face of a respective magnet, a unitary magnetic sheet metal armature assembly comprising an armatur having one end portion in said gap, an intermediate portion between said juxtaposed pole faces and integral magnetic shunt means comprising an element extending substantially perpendicular to said armature along each of the two magnets away from the other magnet, said one end portion of said armature being of material having a higher reversible permeability at high flux densities than the material of said intermediate portion and said intermediate portion being of material having a higher reversible permeability at low flux densities than the material of said one portion, and a signal coil in electromagnetic coupling relation with said armature.
  • An electromagnetic translating device comprising means defining a magnetic circuit having an air gap therein, a vibratile armature having a first portion in said air gap and a second portion coupled to a region in said circuit removed from said air gap, said first portion being of a material having a higher reversible permeability at high flux densities than the material of said second portion and said second portion being of a material having a higher reversible permeability at low flux densities than the material of said first portion, and a signal coil in electromagnetic coupling relation with said armature.
  • An electromagnetic translating device comprising means including permanent magnet means having a neutral point and pole pieces spaced to form an air gap, defining a magnetic circuit, an armature extending from adjacent said neutral point and projecting into said air gap, and a signal coil in electromagnetic coupling relation with said armature, the portion of said armature adjacent said neutral point having a higher reversible permeability at low fiux densities and a lower reversible permeability at high flux densities than the armature portion in said air gap.
  • An electromagnetic translating device comprising a pair of magnets disposed with one pole of one magnet in juxtaposition to the unlike pole of the other magnet, a pair of pole pieces each extending from the other pole of a respective magnet, said pole pieces having juxtaposed tips defining an air gap, an armature having a first portion between the juxtaposed poles of said magnets and having a second portion in said air gap, said first portion having a higher reversible permeability at low flux densities than said second portion and said second portion having a higher reversible permeability at high flux densities than said first portion, and a signal coil in electromagnetic coupling relation with said armature.
  • An electromagnetic translating device comprising a pair of aligned bar magnets substantially equally magnetized in the direction of their alignment and having unlike pol faces in juxtaposition, a pair of pole pieces each extending from the other pole face of a respective magnet, said pole pieces having juxtaposed tips defining an air gap, an armature having a first portion fixed between said juxtaposed pole faces and having a second portion in said air gap, and a signal coil in electromagnetic coupling relation with said armature, said first portion having a higher reversible permeability at low flux densities and 7 2,o11,1 14 lower coercive 10m than said second portlon and and second portion hevln: a hlzher reversible Number permeabilit at high flux densities then sold first 265,485 portion. 847,555 936,503 GRANT G. LAVERY. 1.677.836 REFERENCES CITED 1,876,164

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
  • Reciprocating, Oscillating Or Vibrating Motors (AREA)
US752889A 1947-06-06 1947-06-06 Polarized electromagnet Expired - Lifetime US2511114A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
FR963909D FR963909A (fi) 1947-06-06
US752889A US2511114A (en) 1947-06-06 1947-06-06 Polarized electromagnet
GB15120/48A GB660997A (en) 1947-06-06 1948-06-04 Improvements in or relating to electro-magnetic translating devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US752889A US2511114A (en) 1947-06-06 1947-06-06 Polarized electromagnet

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US2511114A true US2511114A (en) 1950-06-13

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FR (1) FR963909A (fi)
GB (1) GB660997A (fi)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2536179A (en) * 1950-04-05 1951-01-02 Remco Ind Magnetic sound-powered telephonic unit
US2594088A (en) * 1950-05-05 1952-04-22 Westinghouse Electric Corp Polarized relay construction
US2912522A (en) * 1954-06-14 1959-11-10 Industrial Res Prod Inc Electro-mechanical transducing device
US2994016A (en) * 1957-08-28 1961-07-25 Tibbetts Industries Magnetic translating device
US3002058A (en) * 1958-03-07 1961-09-26 Hugh S Knowles Electro acoustic transducer
US3002057A (en) * 1956-03-29 1961-09-26 Vigren Sten Daniel Polarized electromagnetic device
US3054426A (en) * 1958-12-15 1962-09-18 Gen Motors Corp Rotary magnetic actuator
US3128537A (en) * 1958-06-26 1964-04-14 Vigren Sten Daniel Manufacture of electromagnetic devices
DE1173184B (de) * 1958-04-22 1964-07-02 Hugh Shaler Knowles Elektromechanischer Wandler, insbesondere fuer Hoerhilfen
DE1257283B (de) * 1959-11-05 1967-12-28 Tibbetts Industries Elektromagnetischer Wandler
DE1269246B (de) * 1959-11-05 1968-05-30 Tibbetts Industries Magnetischer Wandler
DE1276105B (de) * 1956-03-29 1968-08-29 Claesson Harry Elias Elektromagnetischer Kopfhoerer
US3436568A (en) * 1966-04-19 1969-04-01 Indian Telephone Ind Ltd Electromagnetic vibratory devices
US3531745A (en) * 1969-10-22 1970-09-29 Tibbetts Industries Magnetic translating device with armature flux adjustment means
US4050043A (en) * 1973-12-29 1977-09-20 Elmeg Elektro-Mechanik Gmbh Electromagnetic system

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL282929A (fi) * 1961-09-06
DE1179256B (de) * 1963-04-13 1964-10-08 Lehner Fernsprech Signal Vierpoliges Antriebssystem fuer elektro-akustische Wandler
DE1299039B (de) * 1966-04-19 1969-07-10 Indian Telephone Ind Ltd Doora Elektromagnetische Schwingvorrichtung

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US265485A (en) * 1882-10-03 Electro-magnet
US847555A (en) * 1906-02-05 1907-03-19 Western Electric Co Adjusting device for relays.
US936503A (en) * 1908-01-04 1909-10-12 Charles E Williams Magnetic regulator for audiphone-receivers.
US1677336A (en) * 1925-05-25 1928-07-17 Westinghouse Electric & Mfg Co Induction relay
US1876164A (en) * 1929-07-01 1932-09-06 Magnavox Co Magnetic device
US2013229A (en) * 1931-10-08 1935-09-03 Andis Mathew Power driven hair clipper
US2163161A (en) * 1937-05-20 1939-06-20 Control Instr Co Inc Magnetic unit
US2215782A (en) * 1938-08-31 1940-09-24 Control Instr Co Inc Telephonic unit

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US265485A (en) * 1882-10-03 Electro-magnet
US847555A (en) * 1906-02-05 1907-03-19 Western Electric Co Adjusting device for relays.
US936503A (en) * 1908-01-04 1909-10-12 Charles E Williams Magnetic regulator for audiphone-receivers.
US1677336A (en) * 1925-05-25 1928-07-17 Westinghouse Electric & Mfg Co Induction relay
US1876164A (en) * 1929-07-01 1932-09-06 Magnavox Co Magnetic device
US2013229A (en) * 1931-10-08 1935-09-03 Andis Mathew Power driven hair clipper
US2163161A (en) * 1937-05-20 1939-06-20 Control Instr Co Inc Magnetic unit
US2215782A (en) * 1938-08-31 1940-09-24 Control Instr Co Inc Telephonic unit

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2536179A (en) * 1950-04-05 1951-01-02 Remco Ind Magnetic sound-powered telephonic unit
US2594088A (en) * 1950-05-05 1952-04-22 Westinghouse Electric Corp Polarized relay construction
US2912522A (en) * 1954-06-14 1959-11-10 Industrial Res Prod Inc Electro-mechanical transducing device
US3002057A (en) * 1956-03-29 1961-09-26 Vigren Sten Daniel Polarized electromagnetic device
DE1276105B (de) * 1956-03-29 1968-08-29 Claesson Harry Elias Elektromagnetischer Kopfhoerer
US2994016A (en) * 1957-08-28 1961-07-25 Tibbetts Industries Magnetic translating device
US3002058A (en) * 1958-03-07 1961-09-26 Hugh S Knowles Electro acoustic transducer
DE1173184B (de) * 1958-04-22 1964-07-02 Hugh Shaler Knowles Elektromechanischer Wandler, insbesondere fuer Hoerhilfen
US3521208A (en) * 1958-04-22 1970-07-21 Hugh S Knowles Reluctance adjustment in electromagnetic devices
US3128537A (en) * 1958-06-26 1964-04-14 Vigren Sten Daniel Manufacture of electromagnetic devices
US3054426A (en) * 1958-12-15 1962-09-18 Gen Motors Corp Rotary magnetic actuator
DE1257283B (de) * 1959-11-05 1967-12-28 Tibbetts Industries Elektromagnetischer Wandler
DE1269246B (de) * 1959-11-05 1968-05-30 Tibbetts Industries Magnetischer Wandler
US3436568A (en) * 1966-04-19 1969-04-01 Indian Telephone Ind Ltd Electromagnetic vibratory devices
US3531745A (en) * 1969-10-22 1970-09-29 Tibbetts Industries Magnetic translating device with armature flux adjustment means
US4050043A (en) * 1973-12-29 1977-09-20 Elmeg Elektro-Mechanik Gmbh Electromagnetic system

Also Published As

Publication number Publication date
FR963909A (fi) 1950-07-26
GB660997A (en) 1951-11-14

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