US2534157A - Sound reproducing device - Google Patents

Sound reproducing device Download PDF

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Publication number
US2534157A
US2534157A US97234A US9723449A US2534157A US 2534157 A US2534157 A US 2534157A US 97234 A US97234 A US 97234A US 9723449 A US9723449 A US 9723449A US 2534157 A US2534157 A US 2534157A
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US
United States
Prior art keywords
diaphragm
air gap
sound
voice coil
loudspeaker
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
US97234A
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English (en)
Inventor
Zuerker Siegfried
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.)
General Electric Co
Original Assignee
General Electric Co
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 BE496097D priority Critical patent/BE496097A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US97234A priority patent/US2534157A/en
Priority to GB13849/50A priority patent/GB672467A/en
Application granted granted Critical
Publication of US2534157A publication Critical patent/US2534157A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • H04R9/025—Magnetic circuit
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/06—Loudspeakers

Definitions

  • My invention relates to sound reproducing devices and, more particularly, to sound reproducin'g devices-f the electromagnetic loudspeaker typeinwhich a magnetic: field structure provides an air gap for a voice coil connected to thesound emitting diaphragm;
  • the. conical sound diaphragm of a sound. reproduc, ing device is provided with a folded re-entrant; central portion thereby substantially decreasing. the depth of the diaphragm, a large diameter movable voice coil. being attached to the C113,? phragm at the point of fold thereof.
  • the mag; netic field structure. of the sound. reproducing device is positioned on the inactive. side of the sound diaphragm substantially within the space; defined by the. re-entrant portion of the dia-.-' phragm and the movable, voice. coil, the air gap. of the magnetic structure being spaced from the. bottom thereof by an amount equal.
  • the diaphragm hous ing is providedwith a cylindrical flange. loosely encircling the topof the permanent magnet. field. structure and soldered thereto,.securely toposi tion the; voice coil within; the air gap of thefield structure.
  • Fig. 1 is a plan view of the sound reproducing device; and Fig. 2 is a cross-sectional view of the sound reproducing device taken along the line 2-2 of Fig. 1.
  • an electrodynamic loudspeaker constructed in accordance with my invention comprises a sound emitting diaphragm indicated generally at I, the periphery thereof being supported on a ledge 2 formed in a cone shaped metallic housing 3.
  • the outer portion of diaphragm I is provided with corrugations 4 to allow movement of the diaphragm relative to the supported edge thereof, the edge of the diaphragm being secured to ledge 2 by any means, such as cementing, as will be readily understood by those skilled in the art.
  • the diaphragm I is provided with an outer frusto-conical' portion 5, the central portion of the diaphragm comprising an innerre-entrant frustoconical portion 6.
  • the center of the diaphragm I is provided with an aperture I in which may be seated a dust cap (not shown) to maintain the air gap of the loudspeaker free from dust and foreign particles which would be attracted thereto.
  • the upper edge of the re-entrant portion '5 is preferably spaced a distance A from the upper lip 8 of the conical housing 3, the distance A being equal to the maximum displacement of the inner re-entrant portion of the diaphragm.
  • a large diameter coil form 9 is attached to the diaphragm at the junction point It of the frusto-conical portions thereof.
  • the lower portion of coil form 9 carries a voice coil II, which may be in the form of a plurality of turns of wire wound upon the coil form Qin a manner well known to those skilled in the art.
  • Coil form 9 is attached to point III of the diaphragm by any convenient means. II! the inner edge of an annular corrugated spider I2 is also cemented to the coil form 9, the outer edge of spider I2 being supported on and cemented to a ledge formed at the appropriate point I3 in the conical housing 3. It will be understood that spider I2 serves as a flexible centering device for the voice call assembly and also serves as a dust protective device in a manner similar to that performed by the dust cap discussed above.
  • I provide a permanent magnet field structure comprising an outer cups haped pole piece I4, having an upwardly extending cylindrical side portion I5.
  • magnet I6 of generally cylindricalconfiguration is positioned centrally of the cup-shaped outer pole piece I4, the diameter of permanent magnet It being substantially smaller than the diameter of pole piece I4.
  • Permanent magnet I6 may be' made of any of the well known magnetic alloys having high fiux producing qualities, such as, for example, an alloy of aluminum, nickel and cobalt. Seated on the upper surface of magnet I6 is an inner cup-shaped pole piece I! At this point.
  • a permanent 4 which is provided with a central flat portion conforming to the contour of the magnet 56 and a downwardly extending side portion IS which extends toward the bottom of the outer pole piece I4. Pole pieces I4, IT, and magnet it are held in concentric stacked relationship by any convenient means such as the rivet I9 which is passed through apertures 20 in the pole pieces and the central aperture 21 of the permanent magnet It.
  • the surfaces 22, 23 of the permanent magnet I5 are preferably cemented to the upper and lower pole pieces respectively to prevent dislocation of the members when subjected to shock.
  • inner pole piece I! is spaced from the adjacent side portion of outer pole piece I4 to define an air gap 24 therebetween. While the outer portion I8 of pole piece 57 may be bent at any particular angle so as to define the air gap 24 at any particular point along the side portion I5, I prefer to form the pole piece I? so that the air gap 24 is spaced from the bottom of outer pole piece I4 by a distance B, this distance being substantially equal to the maximum displacement of the voice coil when energized by the conventional electrical signal.
  • the voice coil By spacing the voice coil from the bottom pole piece It by an amount equal to, or only slightly greater than, the voice coil displacement and by positioning the upper edge of re-entrant portion 6 and cone 5 a distance A, equal to the voice coil displacement, from the upper edge of the speaker housing 3 it will be evident that substantially the entire depth of the loudspeaker is determined by the dynamic sound diaphragm and voice coil assembly.
  • the permanent magnet may be of substantial depth it is positioned on the inactive side of the sound diaphragm, within the pocket formed by the re-entrant portion of the sound diaphragm and the coil form 9 so that the permanent magnet field structure contributes little or nothing to the over-all depth of the loudspeaker.
  • the conical housing 3 is provided with a cylindrical, downwardly extending flange portion 25.
  • Flange portion 25 has an inner diameter sufficiently large that it will loosely encircle the side portion I5 of outer pole piece I4, thus allowing considerable lateral and angular movement of the diaphragm and voice coil assembly with respect to the magnetic field structure.
  • flange portion 25 is secured to the outer surface of the field structure by flowing solder therebetween, thereby securing the voice coil I8 in strain-free position within the air gap 24. While the above described.
  • strain-free connection between the permanent magnet field structure and the diaphragm speaker housing is particularly adapted to the strucamee, rev
  • a permanent magnet field structure for an electrodynamic loudspeaker comprising a permanent magnet, a pair of opposed cup-shaped pole pieces of substantially larger diameter than said magnet and having base portions respectively located in spaced parallel planes, means for holding said magnet between said opposed pole pieces in concentric relation thereto, said pole pieces having interfltting edges located in a third plane' located intermediate said parallel planes and spaced to provide an axially disposed annular air gap therebetween.
  • a permanent magnet field structure for an electrodynamic loudspeaker comprising a per manent magnet, a pair of opposed cup-shaped pole pieces of substantially larger diameter than said magnet and having base portions respectively located in spaced parallel planes, means for holding said magnet between said opposed pole pieces in concentric relation thereto, said pole pieces having interfitting edges located in a third plane located intermediate said parallel planes and spaced to provide an axially disposed annular air gap therebetween, said air gap being spaced from the base portion of one of said cup-shaped pole pieces by an amount substantially equal to the maximum travel of a voice coil positioned within said air gap.
  • a cylindrical permanent magnet inner and outer cup-shaped pole pieces of substantially larger diameter than said magnet, means for holding said magnet between said opposed pole pieces in concentric relation thereto, said pole pieces having interfitting edges spaced to provide an axially disposed air gap therebetween, said air gap being spaced from the bottom of one of said cu'p shaped 'pole pieces by an amount substan tially equal to the maximum travel of a voice coilpositioned" within said air gap, a frusto-conical housing attached to said outer cup-shaped pole piece at the periphery thereof, and a folded conical diaphragm supported on the peripheryof said housing, said diaphragm having an outer frusto-conical portion extending from said air gap substantially to the periphery of said housing and disposed inwardly substantially in conformity with the contour of said housing and said diaphragm alsohaving a reversely-directed inner portion joining said outer portion at said air gap and conforming substantially to the contour of said contour of said
  • a magnetic field structure comprising an outer cupshaped pole piece having a base portion and upwardly extending side portions, a permanent magnet of substantially smaller diameter than the diameter of said outer pole piece and positioned centrally on the base portion thereof, a cup-shaped inner pole piece of smaller diameter than said outer pole piece and positioned on said magnet, said inner pole piece having an outer frusto-conical portion extending downwardly around the outside of said magnet and defining an air gap in a plane located intermediate the upper and lower faces of said inner and outer pole pieces, said air gap being spaced from the base portion of said outer pole piece by an amount substantially equal to the maximum travel of a voice coil positioned within said air gap.
  • a permanent magnet field structure having an outer cylindrical surface and having an axially extending annular air gap located therein
  • a cone-shaped housing provided with a cylindrical flange portion at the small end thereof adapted loosely to encircle said cylindrical surface
  • said housing being adapted to have a diaphragm and voice coil assembly attached thereto at the periphery thereof, whereby said voice coil is positioned relative to said flange portion so as to enter said air gap when said cylindrical surface and said cylindrical flange are interfitted, and a bonding material filling the space between said cylindrical flange and said cylindrical surface, thereby to secure said flange and surface together in strain-free position concentric with said air gap.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
US97234A 1949-06-04 1949-06-04 Sound reproducing device Expired - Lifetime US2534157A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE496097D BE496097A (en, 2012) 1949-06-04
US97234A US2534157A (en) 1949-06-04 1949-06-04 Sound reproducing device
GB13849/50A GB672467A (en) 1949-06-04 1950-06-02 Improvements in and relating to sound reproducing devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US97234A US2534157A (en) 1949-06-04 1949-06-04 Sound reproducing device

Publications (1)

Publication Number Publication Date
US2534157A true US2534157A (en) 1950-12-12

Family

ID=22262326

Family Applications (1)

Application Number Title Priority Date Filing Date
US97234A Expired - Lifetime US2534157A (en) 1949-06-04 1949-06-04 Sound reproducing device

Country Status (3)

Country Link
US (1) US2534157A (en, 2012)
BE (1) BE496097A (en, 2012)
GB (1) GB672467A (en, 2012)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2778882A (en) * 1951-01-11 1957-01-22 Lustraphone Ltd Microphones
US3046362A (en) * 1956-11-06 1962-07-24 Stanley F White Speaker
US3125647A (en) * 1964-03-17 Frequency-o cycles sec
US3573396A (en) * 1964-02-05 1971-04-06 Electronic Res Ass Loudspeaker having improved diaphragm
US3679844A (en) * 1970-08-27 1972-07-25 Alpha Products Inc Moving coil loudspeaker using thin magnet
US3937905A (en) * 1972-07-25 1976-02-10 Manger J W Moving voice coil transducer having a flat diaphragm of an impregnated knit
US4306121A (en) * 1979-04-12 1981-12-15 Instrument Systems Corporation Electro-acoustic transducer assembly

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2197649A (en) * 1936-11-14 1940-04-16 Cinaudagraph Corp Loudspeaker and method of formation
US2400662A (en) * 1941-05-27 1946-05-21 Int Standard Electric Corp Telephone transmitter and receiver

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2197649A (en) * 1936-11-14 1940-04-16 Cinaudagraph Corp Loudspeaker and method of formation
US2400662A (en) * 1941-05-27 1946-05-21 Int Standard Electric Corp Telephone transmitter and receiver

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3125647A (en) * 1964-03-17 Frequency-o cycles sec
US2778882A (en) * 1951-01-11 1957-01-22 Lustraphone Ltd Microphones
US3046362A (en) * 1956-11-06 1962-07-24 Stanley F White Speaker
US3573396A (en) * 1964-02-05 1971-04-06 Electronic Res Ass Loudspeaker having improved diaphragm
US3679844A (en) * 1970-08-27 1972-07-25 Alpha Products Inc Moving coil loudspeaker using thin magnet
US3937905A (en) * 1972-07-25 1976-02-10 Manger J W Moving voice coil transducer having a flat diaphragm of an impregnated knit
US4306121A (en) * 1979-04-12 1981-12-15 Instrument Systems Corporation Electro-acoustic transducer assembly

Also Published As

Publication number Publication date
GB672467A (en) 1952-05-21
BE496097A (en, 2012)

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