US1873360A - Loud-speaker construction - Google Patents

Description

Aug. 23, 1932. J. SWALLOW 1,873,360

LOUD SPEAKER CONSTRUCTION Filed June 15, 1929 7 Q9?) van far &5 d osep/z 510a (Ivar M. 153% V Patented Aug. 23, 1932 UNITED; STATES JOSEPH SWALLOW, on BnnwYn, 'rnninols,

ssmme To 5113mm eonnonn'rrom .1

CHICAGO, ILLINOISfA ooRroa'ArIoN on DE AWARE IiO UD- SBEAKER Application filed. June 15,

My. invention relatesbroadly to loud speakers, and has among its other objects the production of devices of the kind described that are eificient,durable, compact and simple in construction. V U I v A particular object of the invention. is to: provide improved means for supporting the diaphragm of'aloud speaker.

Another particular object ofthe invention is to provide improved means for support. ing a movable armature or winding in a loud speaker, the armature or winding being one subjected to telephonic currents and opera. tively connected to a diaphragm.

Still another particular object of the 1nvention is to provide an improved magnetizing structure for loud speakers.

A preferred form of the invention is embodied in a loud speaker which comprises a magnetizingstructure fabricated from parts securely held in alinement "and formedto provide an annular magnetic field in which a winding is disposed, the winding being sub j ected to telephonic currents delivered to it '25 from a radio-receivingset, or the like'. The winding is preferably-supported, upon an annular member secured to afldiaphragm and a rod projecting through the magnetizing structure supports the winding, the annular 80 member and the diaphragm. The rod is supported by spaced spiral spr ng members which exert sufficient tension upon the dia phragm and the winding to hold them in their normal positions, as shown in the draw-. ing, when the winding is not being subjectedto telephonic currents.

Many other objects and advantages will appear as this description progresses, reference being had to the accompanying draw ing, wherein: V r j j V Figure 1 is a central section taken through a loud speaker embodying my. invention, and 1 i Fig. 2 is a front elevation of a spiral spring member which forms part of the loud speaker shown in Fig. 1. j 7

Referring for the present to Fig. l wherein I have shown a loud speaker embodying a preferred form of the invention, the ref- 50 erence character 10 designates generally a 1 18,, or the equivalent.

comm nio isaefiserieu n 371,207.

magnetizing structure-which preferably coin prises a' U-shaped magnet,member lhrthe ends of the magnet member 1-1 having'a rece tangular plate l2 securedto them by screws A rel t y l rge" 5 aperture 1% formed in the rectangular plate 12 is co-axiallydi'sposed with respectgto aperture 15 formed in the magnet member 11. 'Dispo'sedin the aperturel l is oneend.

of a pole piece 16 which is preferablyt'ubu- 6' lar inform projects into theaperture 15. Disposed around the pole piece 16 is a ring 18. formed from non-magnetic material and mounted in a recess 24 formed in thering. 18; is an annularpole piecei22 spacedfrom the pole piece 16 to provide an annular mag-J V netic field. The annular pole piece is pref erably fitted snug y n the p rtur l .Dis,- posed around the polepiece 161's awinding; 23,,wher'eby the magnet member, the rec'- t ngul rp te l2e dthe p0lep e n 22 may be magnetized. Obviously, the mag,- netizing current maybe of such magnitude that the field between the pole pieces l6 and 22 will be relatively intense, the'magnetizing electriccurrent being derived from any suit;

able source, r H 4 e Disposed inthe annular magnetic field provided between the pole'pieces 16 and22 is an electrical conducton armature or winding 26 adapted to be subjected to telephonic currents obtained-from a radio-receiving set, i or the like. The winding 26 is mounted upon an annular'member 27 which maybe; formed fromany suitable material, such as paper, or a phenolic condensation product," Formed integral with theannular meine ber27 is a conical flange 30 in which the apex I of a conicalmember 32, is seated, the conical member 32 being part of the diaphragm which is designated generally by reference character 38 and also comprisesan annulus 34 attached tothei base of the conical portion 32. The conical-portion 32 preferably formed from paper, or the equivalent, but the annulus 34is preferably formed from relatively flexible leather, or the equivalent, The outer edge of the annulusgSl is prefer ablyrigidly secured to a ring 36 formed from sheet metal, or the like, and the ringfi s sup- 100 ported by aplurality of arms 37 which have their outer ends spot-welded to the ring 36 and have their inner ends secured to the magnet member 11 and to frame members 38 by screws 40, or the e uivalent. The frame members 38 may be-o any suitable construc- 'tion and 'are'preferably formed'from sheet.

metal. .They are preferably provided with flanges 41 which may be secured to the mag.-

n'et'member i 11" and to the rectangularplate" 12 by the aforementioned'screws It will be noted that the apex of'the conical portion 32 of the diaphragm 33 is apertured to accommodatearod43 which passes through the aperture and extends. into the conical portion. conical washer 44, the construction belng such Carried by the rod 43 is a that theedge of the conical washer 44 clamps the conical portion 32 against the conical er against .the conical portion32.

flange30. A nut 45 screw-threaded upon the rod 43 maybe manipulated to urge the wash- A -portion of the rod 43 projects into tu- 25' bular pole piece 16 and is preferably enlarged in diameter to provide-an annular shoulder 46 against which a washer 47 is'positioned.

' A nut 48 screw-threaded upon the rod 43 clamps the central portion of the conical por- 7 with the interior surface of the hollow pole have-shown one of them in detail in Fig. 2.

piece 16'and the spiral spring members 50 and 51 are preferably cup-shaped and are preferably soldered v or otherwise. secured within the tube 53. 'The'metal from which the spiral spring members are formed'is preferably thin and relativelyfiexible. I

The-spiral spring members 50 and 51 are preferably identical in construction, and I It will be noted that each of the spiral spring members is preferably formed from a sheet metal stamping, and that each'is provided with a spiral slot 54 to provide a spring 56 having aplurality'of convolutions, the constructlon being such that the springs 56"do not exert sufficient tension on the diaphragm at anytime to distort the soundemitted therefrom. Thus, it is readily understood that the spiral springs 56'are not adapted to subject the diaphragm 33 to-such tension, but that they-are 'adapted'to hold the conical portion 32 of the diaphragm and the winding 26in neutral positions when the Winding 26 is not being subjected to telephonic currents. It might be said that the springs 56 provide a restoring'force of a magnitude corresponding to the magnitude of the electrical currents to which the winding 26 is subjected-F A feature ofthe invention is the manner in which the spiral spring members 5Oand 51 hold the winding 26 and the annular member 27 in concentric relation with the pole pieces 16 and 22, it being well-known to those skilled in the art that because of the relatively small clearance allowedbetween the several'parts of the loud speaker at this point, it isabsolutely. essential thatlthe winding and itssupport shall be 1 retained ,in concentric relation with respect :to the'inner and outer pole pieces.- To prevent frictional engagement between the-fixed and moving parts, which frictional engagement would distort the sounds reproduced by the diaphragm'q 7 Another feature of the invention'is the construction of the magnet [members and pole pieces andthe manner inwhich ,they'are assembled' to remain in permanent alinement even when the speaker is subjected to rough handling,-etc. 1 a

type, the combination "with a magnet includingia tubular pole piece, ofa coil adapted-to 1. In a loud speaker 'of the electromagnetic move in the "magnetic field "of said magnet,

. and supporting means :forsaid coil compris ing flexible members disposed in said pole piece and extending outwardly-with respect to the longitudinal axis of said coil,'said flexible members extending in a non-radial 'direc tion between said longitudinal axis and" a support, said flexible members being disposed substantially at right angles to the direction 7 of movement of the coiland having a length greater than theradialdistance between said longitudinal axis and said support.

' 2. In a si-gnal transmitting device, means including a tubular polepiece form'ing a magnetic air'gap, a current-carrying, coil adapted to move in said airgap, and a. yield ing support for said coil comprising fiat strips of non-elastic flexible material] dis posed in said pole piece and extending out wardly with resp'ectto the longitudinalaxis of said coil, s'aidflat strips extending to fixed points, said strips being positioned with respect to the coil and fixedpoints soth at a twisting str'ain-w'illbe imposed" upon said; strips as the coil moves axially in said-gap.

In testimony whereof, lliave hereunto set my hand'this 17th day; of May, 1929. 1

7 I JOSEPH SWALLOWV.

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