US3222753A - Speaker magnet structure and method of forming the same - Google Patents

Speaker magnet structure and method of forming the same Download PDF

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US3222753A
US3222753A US813911A US81391159A US3222753A US 3222753 A US3222753 A US 3222753A US 813911 A US813911 A US 813911A US 81391159 A US81391159 A US 81391159A US 3222753 A US3222753 A US 3222753A
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retainer
magnet
walls
speaker
coaxially
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US813911A
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Elmore A Heppner
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HEPPNER Manufacturing CO
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HEPPNER Manufacturing CO
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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
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49005—Acoustic transducer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49826—Assembling or joining
    • Y10T29/49879—Spaced wall tube or receptacle
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49826—Assembling or joining
    • Y10T29/49908—Joining by deforming
    • Y10T29/49925—Inward deformation of aperture or hollow body wall
    • Y10T29/49927—Hollow body is axially joined cup or tube
    • Y10T29/49929—Joined to rod
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49826—Assembling or joining
    • Y10T29/49908—Joining by deforming
    • Y10T29/49938—Radially expanding part in cavity, aperture, or hollow body

Definitions

  • This invention relates to magnet structures and in particular to magnet structures for use in loudspeakers.
  • the principal feature of the invention is the provision of a new and improved speaker magnet structure of simple and economical construction.
  • Another feature is the provision of such a speaker magnet structure wherein the magnet is retained in the housing by a new and improved retainer.
  • a further feature of the invention is the provision of such a speaker magnet structure wherein the retainer provides an improved dustproof seal with the housing.
  • Still another feature of the invention is the provision of such a speaker magnet structure wherein the secured relationship of the retainer with the speaker housing is effected by pressure exerted by the ends of the retainer on the opposite housing walls.
  • a still further feature of the invention is the provision of a new and improved method of forming such a speaker magnet structure.
  • a yet further feature is the provision of such a method of forming a speaker magnet structure wherein the retainer is elongated in a novel manner in the securing operation to provide the desired retaining pressure thereof on the opposite walls.
  • FIG. 1 is a side elevation of a speaker magnet structure embodying the invention
  • FIG. 2 is a diametric section thereof
  • FIG, 3 is a vertical section thereof taken substantially along the line 3 3 of FIG. 1;
  • FIG. 4 is a side elevation of a retainer in its original, unextended configuration
  • FIG. 5 is a side elevation of the retainer in the unextended configuration and with a magnet shown in dotted lines secured therein;
  • FIG. 6 is a diametric section of another form of speaker magnet structure embodying the invention.
  • FIG. 7 is a side elevation of the retainer thereof in an unextended configuration with the magnet secured therein.
  • a speaker magnet structure generally designated 11i is shown to comprise an open sided housing having a front wall 12, a rear wall 13, a top wall 14 and a bottom wall 15.
  • Front wall 12 is provided centrally with a circular opening 16 adapted to receive the speaker voice coil (not shown).
  • annular retainer 17 Extending longitudinally between front wall 12 and rear wall 13 coaxially of opening 16 is an annular retainer 17 in which is secured a permanent magnet 18.
  • Retainer 17 comprises an annular member formed of a non-magnetic material, such as a nonferrous metal, to preclude short circuiting of the magnetic field.
  • the retainer may be formed by punch pressing or may be machined, as desired.
  • the rear portion 19 lof the retainer has an original internal diameter smaller than the diameter of the rear portion 20 of the magnet whereby magnet portion 2t) may have a press lit in retainer portion 19 and, thereby, be securely retained therein.
  • the retainer is provided with a front portion 21 having a substantially larger diameter 3,222,753 Patented Dec. 14, 1965 than rear portion 19 and joined to rear portion 19 by a generally transversely outwardly extending, frustoconical portion 22.
  • the forward portion 23 of magnet 18 has a reduced diameter slightly smaller than the diameter of opening 16 to permit the concentric disposition of the speaker voice coil (not shown) thereover.
  • the rear surface 24 of front wall 12 is provided with an annular groove 25 concentrically surrounding opening 16 and receiving the forward end 26 of retainer 17.
  • the method of forming speaker magnet structure 10 is as follows. Rear portion 19 of magnet 18 is forced into rear portion 19 of the retainer 17, as shown in FIG. 5. As the over-all length of retainer 17 in the unextended configuration as seen in FIG. 5 is no greater than the spacing between front wall 12 and rear wall 13 of the housing 11, the assembled retainer and magnet may be positioned in the housing between walls 12 and 13 in coaxial alignment with opening 16. A suitable gauge (not shown) may be employed to effect an accurate centering of the magnet relative to the opening.
  • a pair of semi-annular jaws 27 is now pressed against the exterior of the retainer at outwardly extending portion 22 to reduce the angularity thereof relative to the axis of the retainer and, thereby, effect an over-all elongation of the retainer.
  • front end 26 of the retainer seats in groove 25 to bear forcibly against front wall 12.
  • the outer end 28 of the retainer is concurrently forced against inner surface 29 of rear wall 13, whereby the retainer is forcibly secured between walls 12 and 13.
  • magnet 18 is positively and accurately secured in coaxial relationship with opening 16.
  • a modied form of speaker magnet structure generally designated is shown to comprise a retainer 117 generally similar to retainer 17 but having a rear portion 119 provided with a diameter smaller than that of corresponding rear portion 19 of retainer 17.
  • Rear portion 119 has a press iit with a cylindrical magnet 11S having a uniform diameter corresponding to the diameter of forward portion 23 of magnet 18 and a length substantially equal to the spacing between the front surface 129 of a rear wall 113 and the front surface 130 of a front wall 112 of a housing 111 similar to housing 11.
  • the forward end 123 of magnet 118 projects forwardly of the front end 126 of the retainer 117 to extend longitudinally through opening ⁇ 116 of the front wall.
  • Outwardly extending frusto-conica1 portion 122 of retainer 117 is somewhat longer than corresponding portion 22 of retainer 17 but functions similarly thereto in providing for an increase in the over-all length of the retainer upon a deformation which reduces the agularity.
  • Magnet 118 is installed in retainer 117 subsequent to the disposition of the retainer between the housing walls, and preferably prior to the elongation lof the retainer.
  • the installation of the magnet may be readily effected by urging it through the opening 116 with the retainer disposed coaxially behind the opening.
  • the method of securing a cylindrical speaker magnet between spa-ced walls of a housing and coaxially of an opening in one of the walls comprising the steps of: securing the magnet coaxially in an annular retainer provided with a transversely outwardly extending portion and an original length substantially equal to the spacing between the walls; positioning the retainer coaxially of said opening with the opposite ends of the retainer juxtaposed to said walls; and deforming the outwardly extending portion transversely inwardly toward a longitudinally extending configuration to increase the over-all length of the retainer and cause the ends to press retentively against said walls.
  • the method of securing a speaker magnet between spaced walls of a housing comprising the steps of: seccuring the magnet coaxially in an annular retainer provided with a transversely outwardly extending portion and an original length substantially equal to the spacing between the walls; positioning the retainer with the opposite ends of the retainer juxtaposed to said walls; and deforming the outwardly extending portion transversely inwardly toward a longitudinally extending configuration to increase the over-all length of the retainer and thereby cause the ends to press retentively against said walls, and increase the securing force of the retainer about the magnet.
  • the method of securing a speaker magnet between spaced walls of a housing comprising the steps of; forcing the magnet coaxially into a press tit with an annular retainer provided with a transversely outwardly extending portion and an orginal length substantially equal to the spacing between the walls; positioning the retainer with the opposite ends of the retainer juxtaposed to said walls; and deforming the outwardly extending portion transversely inwardly toward a longitudinally extending contiguration to increase the over-all length of the retainer and cause the ends to press retentively against said walls, and increase the securing force of the retainer about the magnet.
  • the method of securing a cylindrical speaker magnet between spaced walls of a housing and coaxially of an opening in one of the walls comprising the steps of positioning a retainer having a portion substantially conforming to the outer periphery of the magnet and having a transversely outwardly extending portion and an original length substantially equal to the spacing between the walls coaxially of said opening with the opposite ends Iof the retainer juxtaposed to said walls; locating a magnet in said retainer portion, and deforming the outwardly extending portion transversely inwardly toward a longitudinally extending conguration to increase the 1overall length of the retainer and cause the ends to press retentively against said walls, and to secure the magnet coaxially in said retainer portion.
  • the method of securing an object between xedly spaced elements comprising the steps of xedly associating the object with a deformable member having a rst portion extending in one direction and an annular second portion extending laterally therefrom, disposing the member with said portions serially related between the elements, and turning the second portion substantially continuously circumferentially thereof toward a configuration extending in said one direction to elongate the member in said one direction and cause the opposite ends thereof respectively to engage securedly the spaced elements.

Description

Dec. 14, 1965 E. A. HEPPNr-:R 3,222,753
SPEAKER MAGNET STRUCTURE AND METHOD OF FORMING THE SAME j Filed May 18, 1959 Z @921% J/g' United States Patent 3,222,753 SPEAKER MAGNET STRUQTURE AND METHD F FGRMHNG THE SAME Elmore A. Heppner, Round Lake, Ill., assigner to Heppner Manufacturing Co. Filed May 18, 1959, Ser. No. 813,911 Claims. (Cl. 29-155.5)
This invention relates to magnet structures and in particular to magnet structures for use in loudspeakers.
The principal feature of the invention is the provision of a new and improved speaker magnet structure of simple and economical construction.
Another feature is the provision of such a speaker magnet structure wherein the magnet is retained in the housing by a new and improved retainer.
A further feature of the invention is the provision of such a speaker magnet structure wherein the retainer provides an improved dustproof seal with the housing.
Still another feature of the invention is the provision of such a speaker magnet structure wherein the secured relationship of the retainer with the speaker housing is effected by pressure exerted by the ends of the retainer on the opposite housing walls.
A still further feature of the invention is the provision of a new and improved method of forming such a speaker magnet structure.
A yet further feature is the provision of such a method of forming a speaker magnet structure wherein the retainer is elongated in a novel manner in the securing operation to provide the desired retaining pressure thereof on the opposite walls.
Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:
FIG. 1 is a side elevation of a speaker magnet structure embodying the invention;
FIG. 2 is a diametric section thereof;
FIG, 3 is a vertical section thereof taken substantially along the line 3 3 of FIG. 1;
FIG. 4 is a side elevation of a retainer in its original, unextended configuration;
FIG. 5 is a side elevation of the retainer in the unextended configuration and with a magnet shown in dotted lines secured therein;
FIG. 6 is a diametric section of another form of speaker magnet structure embodying the invention; and
FIG. 7 is a side elevation of the retainer thereof in an unextended configuration with the magnet secured therein.
In the exemplary embodiment of the invention, as disclosed in FIGS, 1 through 5 of the drawing, a speaker magnet structure generally designated 11i is shown to comprise an open sided housing having a front wall 12, a rear wall 13, a top wall 14 and a bottom wall 15. Front wall 12 is provided centrally with a circular opening 16 adapted to receive the speaker voice coil (not shown). Extending longitudinally between front wall 12 and rear wall 13 coaxially of opening 16 is an annular retainer 17 in which is secured a permanent magnet 18.
Retainer 17 comprises an annular member formed of a non-magnetic material, such as a nonferrous metal, to preclude short circuiting of the magnetic field. The retainer may be formed by punch pressing or may be machined, as desired. The rear portion 19 lof the retainer has an original internal diameter smaller than the diameter of the rear portion 20 of the magnet whereby magnet portion 2t) may have a press lit in retainer portion 19 and, thereby, be securely retained therein.
As best seen in FIG. 4, the retainer is provided with a front portion 21 having a substantially larger diameter 3,222,753 Patented Dec. 14, 1965 than rear portion 19 and joined to rear portion 19 by a generally transversely outwardly extending, frustoconical portion 22. The forward portion 23 of magnet 18 has a reduced diameter slightly smaller than the diameter of opening 16 to permit the concentric disposition of the speaker voice coil (not shown) thereover. As 4best seen in FIG. 2, the rear surface 24 of front wall 12 is provided with an annular groove 25 concentrically surrounding opening 16 and receiving the forward end 26 of retainer 17.
The method of forming speaker magnet structure 10 is as follows. Rear portion 19 of magnet 18 is forced into rear portion 19 of the retainer 17, as shown in FIG. 5. As the over-all length of retainer 17 in the unextended configuration as seen in FIG. 5 is no greater than the spacing between front wall 12 and rear wall 13 of the housing 11, the assembled retainer and magnet may be positioned in the housing between walls 12 and 13 in coaxial alignment with opening 16. A suitable gauge (not shown) may be employed to effect an accurate centering of the magnet relative to the opening.
A pair of semi-annular jaws 27 is now pressed against the exterior of the retainer at outwardly extending portion 22 to reduce the angularity thereof relative to the axis of the retainer and, thereby, effect an over-all elongation of the retainer. As a result of this elongation, front end 26 of the retainer seats in groove 25 to bear forcibly against front wall 12. The outer end 28 of the retainer is concurrently forced against inner surface 29 of rear wall 13, whereby the retainer is forcibly secured between walls 12 and 13. Thus, magnet 18 is positively and accurately secured in coaxial relationship with opening 16.
Referring now to FIGS. 6 and 7, a modied form of speaker magnet structure generally designated is shown to comprise a retainer 117 generally similar to retainer 17 but having a rear portion 119 provided with a diameter smaller than that of corresponding rear portion 19 of retainer 17. Rear portion 119 has a press iit with a cylindrical magnet 11S having a uniform diameter corresponding to the diameter of forward portion 23 of magnet 18 and a length substantially equal to the spacing between the front surface 129 of a rear wall 113 and the front surface 130 of a front wall 112 of a housing 111 similar to housing 11. Thus, the forward end 123 of magnet 118 projects forwardly of the front end 126 of the retainer 117 to extend longitudinally through opening `116 of the front wall. Outwardly extending frusto-conica1 portion 122 of retainer 117 is somewhat longer than corresponding portion 22 of retainer 17 but functions similarly thereto in providing for an increase in the over-all length of the retainer upon a deformation which reduces the agularity.
Magnet 118 is installed in retainer 117 subsequent to the disposition of the retainer between the housing walls, and preferably prior to the elongation lof the retainer. The installation of the magnet may be readily effected by urging it through the opening 116 with the retainer disposed coaxially behind the opening.
While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as dened in the appended claims.
I claim:
1. The method of securing a cylindrical speaker magnet between spa-ced walls of a housing and coaxially of an opening in one of the walls, comprising the steps of: securing the magnet coaxially in an annular retainer provided with a transversely outwardly extending portion and an original length substantially equal to the spacing between the walls; positioning the retainer coaxially of said opening with the opposite ends of the retainer juxtaposed to said walls; and deforming the outwardly extending portion transversely inwardly toward a longitudinally extending configuration to increase the over-all length of the retainer and cause the ends to press retentively against said walls.
2. The method of securing a speaker magnet between spaced walls of a housing, comprising the steps of: seccuring the magnet coaxially in an annular retainer provided with a transversely outwardly extending portion and an original length substantially equal to the spacing between the walls; positioning the retainer with the opposite ends of the retainer juxtaposed to said walls; and deforming the outwardly extending portion transversely inwardly toward a longitudinally extending configuration to increase the over-all length of the retainer and thereby cause the ends to press retentively against said walls, and increase the securing force of the retainer about the magnet.
3. The method of securing a speaker magnet between spaced walls of a housing, comprising the steps of; forcing the magnet coaxially into a press tit with an annular retainer provided with a transversely outwardly extending portion and an orginal length substantially equal to the spacing between the walls; positioning the retainer with the opposite ends of the retainer juxtaposed to said walls; and deforming the outwardly extending portion transversely inwardly toward a longitudinally extending contiguration to increase the over-all length of the retainer and cause the ends to press retentively against said walls, and increase the securing force of the retainer about the magnet.
4. The method of securing a cylindrical speaker magnet between spaced walls of a housing and coaxially of an opening in one of the walls, comprising the steps of positioning a retainer having a portion substantially conforming to the outer periphery of the magnet and having a transversely outwardly extending portion and an original length substantially equal to the spacing between the walls coaxially of said opening with the opposite ends Iof the retainer juxtaposed to said walls; locating a magnet in said retainer portion, and deforming the outwardly extending portion transversely inwardly toward a longitudinally extending conguration to increase the 1overall length of the retainer and cause the ends to press retentively against said walls, and to secure the magnet coaxially in said retainer portion.
5. The method of securing an object between xedly spaced elements, comprising the steps of xedly associating the object with a deformable member having a rst portion extending in one direction and an annular second portion extending laterally therefrom, disposing the member with said portions serially related between the elements, and turning the second portion substantially continuously circumferentially thereof toward a configuration extending in said one direction to elongate the member in said one direction and cause the opposite ends thereof respectively to engage securedly the spaced elements.
References Cited by the Examiner UNITED STATES PATENTS 1,058,210 4/1913 Welch 29-522 1,561,872 11/1925 Lovejoy. 1,711,182 4/1930 Shrum. 1,856,774 5/19312 Mayer 179-1155 1,941,477 1/1934 Jensen. 2,020,212 11/1935 Quam 29-155.5 2,141,949 12/1938 Carbonneau 29-155.5 X 2,174,355 9/1939 Sundstrom 179-1155 2,221,209 11/1940 Sims. 2,666,980 1/ 1954 Russell 29-155.5 3,092,694 6/ 1963 Walczak 29-155.5 X
FOREIGN PATENTS 497,652 12/ 1950 Belgium.
389,898 3/1933 Great Britain.
397,617 8/1933 Great Britain.
WHITMORE A. WILTZ, Primary Examiner.
NEDWIN BERGER, JOHN F. CAMPBELL, Examiners.

Claims (1)

1. THE METHOD OF SECURING A CYLINDRICAL SPEAKER MAGNET BETWEEN SPACED WALLS OF A HOUSING AND COAXIALLY OF AN OPENING IN ONE OF THE WALLS, COMPRISING THE STEPS OF: SECURING THE MAGNET COAXIALLY IN AN ANNULAR RETAINER PROVIDED WITH A TRANSVERSELY OUTWARDLY EXTENDING PORTION AND AN ORIGINAL LENGTH SUBSTANTIALLY EQUAL TO THE SPACING BETWEEN THE WALLS; POSITIONING THE RETAINER COAXIALLY OF SAID OPENING WITH THE OPPOSITE ENDS OF THE RETAINER JUXTAPOSED TO SAID WALLS; AND DEFORMING THE OUTWARDLY EX-
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3293378A (en) * 1963-06-28 1966-12-20 Heppner Mfg Co Loudspeaker
US3448505A (en) * 1963-12-10 1969-06-10 Renault Method of manufacturing internal combustion engine cylinder heads
US3492443A (en) * 1967-04-14 1970-01-27 Clifford B Digre Dust shield and pressure element for speaker magnet assembly
USD940115S1 (en) * 2018-03-26 2022-01-04 Viablue, Gmbh Absorber for a loudspeaker
USD956021S1 (en) * 2018-03-26 2022-06-28 Viablue Gmbh Spike for a loudspeaker

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE497652A (en) * 1949-08-18
US1058210A (en) * 1910-12-30 1913-04-08 Allie Ray Welch Method of finishing castings.
US1561872A (en) * 1925-03-26 1925-11-17 Ralph M Lovejoy Process of permanently sealing an aperture and the seal therefor
US1711182A (en) * 1926-05-11 1929-04-30 Colona Mfg Company Apparatus for making expansion couplings
US1856774A (en) * 1930-11-15 1932-05-03 American Bosch Magneto Corp Loud speaker construction
GB389898A (en) * 1931-11-03 1933-03-30 Darwins Ltd Improvements in or relating to permanent magnets
GB397617A (en) * 1932-05-13 1933-08-31 Everett Ross Dempster Loud speakers
US1941477A (en) * 1931-07-25 1934-01-02 Jensen Radio Mfg Company Method of making magnetic sound reproducers
US2020212A (en) * 1935-09-06 1935-11-05 James P Quam Method of making dynamic speakers
US2141949A (en) * 1937-04-17 1938-12-27 Utah Radio Products Company Loudspeaker
US2174355A (en) * 1936-02-01 1939-09-26 Sundstrom Pressed Steel Co Loudspeaker and method of making same
US2221209A (en) * 1938-02-17 1940-11-12 Ernest M Sims Method of making jacketed rods and the like
US2666980A (en) * 1947-04-02 1954-01-26 Rola Company Inc Method of making loud-speakers
US3092694A (en) * 1959-02-16 1963-06-04 Rca Corp Loudspeaker

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1058210A (en) * 1910-12-30 1913-04-08 Allie Ray Welch Method of finishing castings.
US1561872A (en) * 1925-03-26 1925-11-17 Ralph M Lovejoy Process of permanently sealing an aperture and the seal therefor
US1711182A (en) * 1926-05-11 1929-04-30 Colona Mfg Company Apparatus for making expansion couplings
US1856774A (en) * 1930-11-15 1932-05-03 American Bosch Magneto Corp Loud speaker construction
US1941477A (en) * 1931-07-25 1934-01-02 Jensen Radio Mfg Company Method of making magnetic sound reproducers
GB389898A (en) * 1931-11-03 1933-03-30 Darwins Ltd Improvements in or relating to permanent magnets
GB397617A (en) * 1932-05-13 1933-08-31 Everett Ross Dempster Loud speakers
US2020212A (en) * 1935-09-06 1935-11-05 James P Quam Method of making dynamic speakers
US2174355A (en) * 1936-02-01 1939-09-26 Sundstrom Pressed Steel Co Loudspeaker and method of making same
US2141949A (en) * 1937-04-17 1938-12-27 Utah Radio Products Company Loudspeaker
US2221209A (en) * 1938-02-17 1940-11-12 Ernest M Sims Method of making jacketed rods and the like
US2666980A (en) * 1947-04-02 1954-01-26 Rola Company Inc Method of making loud-speakers
BE497652A (en) * 1949-08-18
US3092694A (en) * 1959-02-16 1963-06-04 Rca Corp Loudspeaker

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3293378A (en) * 1963-06-28 1966-12-20 Heppner Mfg Co Loudspeaker
US3448505A (en) * 1963-12-10 1969-06-10 Renault Method of manufacturing internal combustion engine cylinder heads
US3492443A (en) * 1967-04-14 1970-01-27 Clifford B Digre Dust shield and pressure element for speaker magnet assembly
USD940115S1 (en) * 2018-03-26 2022-01-04 Viablue, Gmbh Absorber for a loudspeaker
USD956021S1 (en) * 2018-03-26 2022-06-28 Viablue Gmbh Spike for a loudspeaker

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