US2522859A - Electrodynamic loudspeaker and mounting therefor - Google Patents

Description

p 1950 s. s. CARBONNEAU 2,522,859

ELECTRODYNAMIC LOUDSPEAKER AND MOUNTING THEREFOR Filed Jan. 30, 1948 IN VEN TOR. 60/0 00 6. 60/50/7020 Patented Sept. 19, 1950 UNITED STATES PATENT OFFICE Gordon S. Carbonneau, Grand Rapids, Mich.

Application January 30, 1948, Serial No. 5,329

14 Claims. (Cl. 179115.5)

This invention relates to improvements in radio loud speakers.

The principal objects of this invention are:

First, to provide a housing and magnetic structure for a loud speaker which will require less steel than conventional structures and at the same time improve the magnetic and acoustic characteristics of the speaker.

Second, to provide a radio loud speaker which is more rigid than conventional speakers thus eliminating to a large degree undesirable vibrations in the frame structure.

Third, to provide a mounting for the cone of a loud speaker with a reduced amount of material overlying the rear of the cone thus eliminating a large amount of the interference and sound pressure peaks caused by the reflection of sound waves from the frame structure to the rear of the cone.

Fourth, to provide a mounting for the cone of a loud speaker having an accurately controllable effective clamp ring diameter and providing a maximum accessibility to the several elements of the speaker to permit easy installation and inspection of the elements.

Fifth, to provide a mounting for the cone of a loud speaker which eifectively protects the front and back of the cone where the cone is most liable to be damaged during mounting in a radio set and which may be easily clamped to a support without danger of distorting the frame and thus causing undesirable strains in the speaker cone.

Sixth, to provide a loud speaker structure which will have a maximum degree of magnetic efiiciency with a minimum amount of steel due to the location of more metal along the point of greatest magnetic reluctance and reducing the amount of metal where it will cause magnetic leakage from the speaker magnet.

Other objects and advantages pertaining to the details and economies of my invention will be apparent from a consideration of the following description and claims. The drawings, of which there is onesheet, illustrate a preferred form of my loud speaker.

Fig. 1 is a side elevational view of my speaker mounted on a suitable support and partially broken away in vertical cross section along the line l--! in Fig. 2 to illustrate details of construction thereof.

Fig. 2 is a rear elevational view of my speaker partially broken away in vertical cross section along the line 2-2 in Fig. 3.

Fig. 3 is a longitudinal cross sectional view through the magnet of my speaker taken along the line 3-3 in Figs. 1 and 2.

leaving a recess 10.

Fig. 4 is a fragmenetary perspective view of the foot for attaching my speaker to the support.

The supporting structure for my speaker which takes the place of conventional basket structures consists of an annular ring I of relatively heavy gage metal having a forwardly opening cylindric flange '2 and a flat back flange 3 defining the clamp ring opening 4. The ring I is secured to a single strap 5 of relatively heavy gage steel having a central base 6 from which the arm portions 1 diverge toward the edges of the ring. The outer ends of the arms I are bent forwardly and are slightly concave as at 8 to fit closely along the outside of the cylindric flange 2 of the ring. The forwardly bent portions 8 have the feet 9 stamped and folded upwardly therefrom thus The feet 9 define the slots H (see Fig. 4) for receiving the mounting bolts I2 for clamping the speaker to a support panel 13.

The magnet structure of my speaker is secured to the base 6 of the strap and consists of a loop magnet l4 formed of a strip of heavy gage steel folded into rectangular shape with its ends forming an air gap l5 opposite the center of the base 6 of the strap. The magnet loop is is, preferably formed with small projections on its forward face and pressure welded to the base of the strap as at l6. It will be noted from Figs. 1 and 2 that the base 6 of the strap thus forms an. integral and substantial bridge for the .air gap of the magnet loop I4 materially reducing the magnetic reluctance of the air gap so that I am able to form the loop 14 of substantially lighter gage material than is required in other magnets to obtain comparable operating results.

After the loop M has been welded to the base of the strap the coil aperture I i can be accurately reamed through both the strap and the magnet and centered along. the air gap l5. The remaining elements of my speaker are of more or less a conventional design including the pole piece [8 having a reduced forward end l9 projecting into the coil opening anda mounting ring 20 engaged with a shoulder on the pole piece. The voice coil 2| is wound on paper tube 22 and a sealing diaphragm 23 is cemented to the forward face of the base of the strap and to the circumference of the tube.

My cone 24 is of conventional paper or fiber construction having an annular mounting flange 25 around the forward edge thereof which is cemented to the inturned flange 3 of the clamp ring. The rear end of the cone 24 is provided with a cylindrical flange 26 cemented to the forward end of the voice coil .tube and a dust shield 21 is provided at the inner end of the speaker cone to prevent the entrance of dust into the speaker coil tube.

One arm of the strap defines a rectangular aperture 3i! bridged by an insulating terminal stri 35 on which are mounted the terminals 32. Lead. wires 33 connect the terminals 32 to the voice coil 2|.

Particular attention is called to Figs. 1 and i in which it will be noted that the cylindric flange 2 of the clamp ring is welded to the forwardly bent portions of the strap as at 28 with the for ward edge of the flange 2 spaced slightly inwardly from the feet 9 on the strap. Thus when the feet are clamped to the supporting panel by the bolts E2 the forward edge of the clamp ring will be spaced slightly from the rear surface of the panel 53 as at It is thus impossible for an inexperienced or careless workman to clamp the speaker to the panel 53 in such a fashion as to distort or twist the clamp ring i. If desired, rubber bumpers 34 may be positioned between the free edges of the clamp ring and the supporting panel. l3 to dampen any possible vibration of the speaker but in most cases this is unnecessary. The base of the feet 9 is cut away as at 35 so that in any case where the feet are not exactly parallel to the supporting panel is the feet can twist at their relieved portion without distorting the clamp ring.

s It should further be noted that the clamp ring opening 4 is entirely unobstructed and has an accurately controllable sharp forward edge so that when the attaching flange 25 of the speaker cone is cemented thereto it is impossible for any portion of the speaker cone to be cemented to the clamp ring inside of the clamp ring diameter. The connection to the suspended portion of the speaker cone is thus accurately circular and. the cone is entirely free to vibrate under the influence of the voice coil without distortion.

It will be noted from Fig. 2 that the rear sur face of the speaker cone is largely unobstructed so that there is little chance for the reflection of sound waves from the strap to the rear of the cone to cause interference and sound pressure peaks in the response curve of the speaker cone. It will further be noted that due to the absence of any metal along thesides of the loop magnet i ithere is little tendency for the magnet flux to stray from the path of least resistance through the magnet and the base 6 of the strap. This further increases the efficiency of my magnet and speaker assembly as a whole.

In addition to the operating advantages and structural economies of my loudspeaker, the con struction of my speaker mount is particularly advantageous in preventing or reducing the amount of accidental damage to speaker cones incident to manufacture and installation of the loudspeakers in radio sets. Most cone damage has been inflicted in the past from the front of the speaker, either due to mounting screws which project from the baffle puncturing the cone, or from laying the cone down on some pro jecting object on a bench.

My mount protects the cone from these hazards in the following manners:

First, the cylindrical flange 2 is deeper than in speakers previously devised and the forwardly displaced mounting feet 9 coupled with the flange serve to protect the cone from accidental contact with projecting objects;

Second, the mounting holes H are spaced laterally from the ring so there is less likelihood of a workman accidentally placing the cone over Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A radio loud speaker comprising an annular clamp ring having a cylindrical forward fiange and a flat rear flange defining a circular clamp ring opening, a strap having a base parallel to said clamp ring with arms diverging from each end thereof, one of said arms defining an aperture, forwardly bent portions on the ends of said arms welded to the outside of said cylindrical flange and projecting forwardly thereof, said forwardly bent portions being concave to fit ring, attaching feet stamped from said forwardly bent portions of said arms and bent radially out-- wardly of said ring, a loop magnet of rectangularly folded strap metal welded to said base of said strap with the ends of said magnet positioned in the middle of said base, said magnet and base defining a coil opening centered with respect to the ends of said magnet and said strap, a speaker cone having an annular attaching flange around the outer edge thereof cemented to said rear flange of said clamp ring, an electromagnetic structure for actuating said cone associated with said magnet and the rear end of said cone, an insulating terminal strip bridging said aperture, and voice coil leads for said electro-magnetic structure secured to said terminal strip and extending through said aperture.

2. A radio loud speaker comprising an annular clamp ring having a cylindrical forward flange and a flat rear flange defining a circular clamp ring opening, a strap having a base parallel to said clamp ring with arms diverging from each end thereof, one of said arms defining an aperture, forwardl bent portions on the ends of said arms welded to the outside of said cylindrical flange and projecting forwardly thereof, attaching feet stamped from said forwardly bent portions of said arms and bent radially outwardly of said ring, a loop magnet of rectangularly folded strap metal welded to said base of said strap with the ends of said magnet positioned in the middle of said base, said magnet and base definin a coil opening centered with respect to the ends of said magnet and said strap, a speaker cone having an annular attaching flange around the outer edge thereof cemented to said rear flange of said clamp ring, an electro-magnetic structure for actuating said 'cone associated with said magnet and the rear end of said cone, an insulating terminal strip bridging said aperture, and voice coil leads for said electromagnetic structure secured to said terminal strip.

3. A radio loud speaker comprising an annu lar clamp ring having a cylindrical forward flange and a flat rear flange defining a circular clamp rin opening, a strap having a base parallel to said clamp ring with arms diverging from each end thereof, forwardly bent portions on the ends of said arms welded to the outside of said cylindrical flange and projecting forwardly thereof, attaching feet stamped from said for' wardly bent portions of said arms and :bent radially outwardly of said ring, a loop magnet of rectangularly folded strap metal welded to said base of said strap with the ends of said magnet positioned in the middle of said base, said magnet and base defining a coil opening centered with respect to the ends of said magnet and said strap, a speaker cone having an annular attaching flange around the outer edge thereof cemented to said rear flange of said clamp ring, and electro-magnetic structure for actuating said cone associated with said magnet and the rear end of said cone.

4. A radio loud speaker comprising an annular clamp ring having a cylindrical forward flange and a flat rear flange defining a circular clamp ring opening, .a .strap having a base parallel to said clamp ring with arms diverging from each end thereof, forwardly bent portions on the ends of said arms welded to the outside of said cylindrical flange, attaching feet stamped from said forwardly bent portions of said arms and bent radially outwardly of said ring, a loop magnet of rectangularly folded strap metal welded to said base of said strap with the ends of said magnet positioned against said base, said magnet and base defining a coil opening, a speaker cone having an annular attaching flange around the outer edge thereof cemented to said rear flange of said clamp ring, and electro-magnetic structure for actuating said cone associated with said magnet and the rear end of said cone.

5. A radio loud speaker comprising an annular clamp ring having a cylindrical forward flange and a flat rear flange defining a circular clamp ring opening, a strap having a base parallel to said clamp ring with arms diverging from each end thereof, forwardly bent portions on the ends of said arms welded to the outside of said cylindrical flange, attaching feet on said forwardly bent portions of said arms and bent radially outwardly of said ring and lying in a plane forwardly of said ring, a loop magnet of rectangularly folded strap metal welded to said base of said strap with the ends of said magnet positioned against said base, said magnet and base defining a coil opening, a speaker cone having an annular attaching flange around the outer edge thereof secured to said rear flange of said clamp ring, and structure for actuating said cone associated with said magnet and the rear end of said cone.

6. Supporting structure for a radio loud speaker cone comprising an annular clamp ring having a cylindrical forward flange and a fiat rear flange defining a circular clamp ring opening, a single strap member having a base parallel to said clamp ring with arms diverging forwardly from the ends thereof, forwardly bent portions on the ends of said arms lapped upon the outside of said cylindrical flange and welded thereto, said forwardly bent portions being slightly concave to match the curvature of said ring, attaching feet stamped from said forwardly bent portions of said strap and turned radially outwardly from said ring, said feet defining bolt receiving slots and lying in a plane spaced forwardly of the end of said cylindrical flange, and a loop magnet having an air gap therein and welded to the base of said strap with said air gap positioned against the center of said base to be bridged thereby, said base and loop magnet defining a voice coil aperture centered on said air gap.

7. Supporting structure for a radio loud speaker cone comprising an annular clamp ring having a cylindrical forward flange and a flat rear flange defining a circular clamp ring opening, a single strap member having a baseparallel to said clamp ring with arms diverging forwardly from the ends thereof, forwardly bent portions on the ends of said arms lapped upon the outside of said cylindrical flange and welded thereto, said forwardly bent portions being slightly concave to match the curvature of said ring, attaching feet stamped from said forwardly bent portions of said strap and turned radially outwardly from said ring, said feet defining bolt receiving apertures, and a loop magnet having an air gap therein and welded to the base of said strap with said air gap positioned against said base to be bridged thereby, said base and loop magnet defining a voice coil aperture centered on said air gap.

8. Supporting structure for a radio loud speaker cone comprising an annular clamp ring having a cylindrical flange and a flat flange defining a circular clamp ring opening, a single strap member having a base parallel to said clamp ring with arms diverging forwardly from the ends thereof, forwardly bent portions on the ends of said arms lapped upon the outside of said cylindrical flange and welded thereto, attaching feet on said forwardly bent portions of said strap and turned radially outwardly from said ring, said feet defining bolt receiving apertures and lying in a plane spaced forwardly of the end of said cylindrical flange, and a loop magnet having an air gap therein and welded to the base of said strap with said air gap positioned against said base to be bridged thereby, said base and loop magnet defining a voice coil aperture.

9. In a radio loud speaker, a loop magnet of rectangularly folded strap metal having an air gap across the forward side thereof, a strap metal bridge for said air gap welded to the forward side of said magnet and substantially co-extensive therewith, said bridge and magnet defining a voice coil opening centered on said air gap, forwardly diverging arms extending from the ends of said bridge, forwardly bent portions on the outer ends of said arms, outwardly bent attaching feet on the ends of said forwardly bent portions and defining apertures for receiving mounting bolts, and a clamp ring having a cylindrical flange Welded to said forwardly bent portions on said arms, said clamp ring having a flat flange within said arms defining a circular clamp ring opening.

10. In a radio loud speaker, a loop magnet of rectangularly folded metal having an air gap across the forward side thereof, a metal bridge for said air gap welded to the forward side of said magnet and substantially as wide as said magnet, said bridge and magnet defining a voice coil opening, forwardly diverging arms extending from the ends of said bridge, forwardly bent portions on the outer ends of said arms, outwardly bent attaching feet on the ends of said forwardly bentportions and defining apertures for receiving mounting bolts, and a clamp ring having a cylindrical flange welded to said forwardly bent portions onsaid arms, said clamp ring having a flat flange within said arms defining a clamp ring opening.

11. In a radio loud speaker, a loop magnet of rectangularly folded metal having an air gap across the forward side thereof, a metal bridge for said air gap Weldedto the forward side of said magnet and substantially as wide as said magnet, said bridge and magnet defining a voice coil opening, forwardly diverging arms extending from the ends of said bridge, outwardly bent attaching feet on the ends of said arms and defining apertures for receiving mounting bolts, and a clamp ring having a flange welded to said arms, said clamp ring having a flat flange within said arms defining a clamp ring opening.

12. In a radio loud speaker a loop magnet of rectangularl folded metal having an air gap across one side thereof, a metal bridge for said air gap welded to said magnet, forwardly diverg ing arms extending from the ends of said bridge, outwardly bent attaching feet on the ends of said arms and defining apertures for receiving mounting bolts, and a clamp ring having a flange welded to said arms, said clamp ring having a fiat flange within said arms defining a clamp ring opening.

13. Means for mounting the loop magnet of a radio loud speaker on'the clamp ring of the speaker comprising, a strap of steel having a base portion with forwardly diverging arms on the ends thereof, forwardly bent generally parallel portions on the outer ends of said arms adapted to be welded to the outside of said clamp ring,

and outwardly turned attaching feet struck from said forwardly bent portions on the forward ends thereof, said base being adapted to be welded to a side of said magnet, said base being approxi-- mately the same dimension as the side of the magnet.

14. Means for mounting the loop magnet of a radio loud speaker on the clamp ring of the speaker comprising, a strap of steel having a base portion with forwardly diverging arms on the ends thereof, said arms having forwardly folded portions on the ends thereof adapted to be welded to said clamp ring and having outwardly turned attaching feet on the forward ends of said forwardly folded portions, said base being approximately the same dimension as the side of the magnet.

' GORDON S. CARBONNEAU.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,805,459 Batcher May 12, 1931 2,016,453 Olney Oct. 8, 1935 2,027,473 C'reager et al Jan. 14, 1936 2,141,949 Carbonneau Dec. 27, 1938 2,174,355 Sundstrom Sept. 25, 1939 2,178,030 Bowley Oct. 31, 1939 FOREIGN PATENTS Number Country Date 407,474 Great Britain Mar. 22, 1934

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