US1480785A - Diaphragm for sound reproducers - Google Patents

Description

Jan. 15,1924. 1,480,785

C. E. SEMPLE, JR

DIAPHRAGM FOR SOUND REPRODUCERS l Filed May 24. 1922 v Apzeferred and.

the ollnwing .iste ispee fieation. Thisinirentioxrrelutes, to an imp ngement I A primery object pf the inrentlon is to; providegegliephrs, ,thet grill giYe e'eleefif well defined repro notion; of ampleyo'lu'mef 1 but: without-:3. harshnesgt-while at the same timeavoidingwany tendency to inufile or sup press; the 5011116." 5T9 that end the' invent1on a has -in view A. 9, diaphragm that is H h t; ree

Patented an 15, .1924.

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To all whom it" may. ooncem Beit known that I. J r., afcitizenfiof the United Stutes,.=r-e siding,

,ut Youngs ,wn in the eountyej Mehoning 'andEState-pfk )hio, w--heve;invented eertain new P and r 1iseful-z.-,Impi1o);cnientsin Din; phra s fon sound-."lleproducel's, u'ln eh in. diuphri lgms I0 1 z-reproducers ,of

weight, ver "-,sensit1v e, and tpi eetice from resulting f rom ,loe'alfect on of the- -.diephragrn itself.

wA- further objectnof the invention is to provide -t a -.,di uphragm, ha'ving', structural features and characteristics; which niateri. ally contribute tolitslproper functioning,

comprising: a novel distribution and 31rrangement of reinforcing and absorbing elements designed to .prevent the diaphragm from vibruting 1n vpartials which, as is well known bythose familiar with. the operation I of reproducers, produces sounds foreign to the record,

-A furtherobject of theinvention is to utilize appropriate, resonant n'nd suherous materials combineduin a manner to elfeetuall overcome many of the difficulties hereto ore encountered indinphragms of the plate type.

With the above and other ob ects in ,view whichiwill more readily' appear as the na-' ture of the, invention is better .undcrstoodql the same; consists in. the novel constructi on combination underrangementof parts here:

inafte'. more ifullydeseribed, illustrated and claimed.

Figures 6, 7, 8 and 9are also cross secractical embodiment 0E1 tidnal vievrs illustrating further modifiesthroughout thedrawing fi-s th" flat plate typ Wh Diephraig ms 4' used; ';urelropen ztof the f objection "that they 1 m precticall unrestrained" j-tlieirfi operetionhind t erefore produce feigm'drfnnrecordedsounds. :v

Byltlie way oi illustration reference may he hadkt'o Figurei 10 foffthe drawings. which shows a fiat late ieph're'tgni'iR he. vi ngg coneted te t to; 'centm l' fiportionthereof a "stylus-liar connectirfg,fliillt -Sia'nd' held et its outer edges between" the "**gaskets '1 of the reproducer' frainer This'itype of diaplira in may moveias a'whole, a's'mdicated-bj' t c dottedlines m,'-but it"also' vibrates irr partiulsf, as'indieated bythe lines 3/ and z, thereby'producing the points 10 of practically no vibration-known asnodal points, and the'ventrul segments 10' or points of greatest vibration. The formation of these pa'i'tials is due to the' fact that when the vibration, through the stylus'-bar link conriiiti n member S, -:icts on the diaphragm it tends to buckle or depress the area, immediately surronndin the center, while the next section of .thediaphragm takes a reverse position etc; to-the periphery ()fthe diaphragm; l Vl to' the partials, thus forming the dia- 'phregm-generated sounds, I

As'previouslyindicated, it is one of the "princi alobje'cts of the present invention to 'rovi e e diaphra'ginjthat will tend to avoid to itself; Tti'thisend' the invention contemFlates'a main-:diaphra D rrh'ich is pre erably made of-verytlii: flexible material that is hard and stiff. In this connectionI have found that materials of a fibrous nature immersed in a; bath of res inous materiel, such as shellac or compounds of shellac and other materials, and allowed .to dry andthcn worked between heatei dies is very suitable. That is to say, several sheets otcomparatively thin paper, sin-l1 as tissue paper, may he dipped into a tions of the construction wherein? the centrel part of the diaphragmis of eom'pound the sevhe formation of foreign sounds peculiarien the diaphragm rebounds a reverse action takes place with reference Ill) , communicate the diaphragm. That is to say,

' center, themajor bend resinous varnish and allowed to dry and then pressed together between hot plates or dies, which transforms the se arate sheets into one unitary structure 0 the desired thickness. Or, pn the other hand, a single sheet of sufiicient weight may be used, which, after proper treatment, may be pressed into the desired thickness and form. In its rimary aspect, therefore, the present diap ra m contemplates a main .diaphra D, ig. 2, comprisin a disk of a suite 1e relatively elastic ma rial in combination-with a stifiening plate or reinforc in disk 4: and. a rin F of relatively soft or $11 rous material 1i e cork, the central portion D of the diaphragm being deflected to one side of the plane of the body thereof to provide increasing stifi'ness and reinforcement' and also to reduce the tendenpy to vibrate in partials. Referring now more specifically to Figure 2 ofthe drawings, it will be observed that the main diaphragm D has its central portion D pressed into a substantially crowned or ofiset portion 1, theicenter of which, adjacent the opening 2, is preferably given a substantially conical form 3. The concave side of the crowned portion is preferably provided with a reinforcing member 4 of the same material as the diaphragm, which gives added strength and reinforcement to that portion of t e diaphragm subjected to the greatest strain.

Between the outer edge of the reinforcement 4 and the periphery of the crowned portion 1, is secured a cork or quivalent ring F. This ring is preferably ofgraduated cross sectional area, decreasin in thickness toivards the peri hery, all its inner edge 5 overlaps the ed e of the reinforcement 4 so that no wea mess may dcvelvovp in this region.

ith the construction held'in the reproducer frame by means of the usual askets T, the offset central portion I) ten sto vibrate asawhole, while the bending or flexing takes place inthe flat portion, or annulus D at the outer edge of the vibratmg energy is the cone-shaged central part 3, and then to the larger central or crown portion 1, which, by reason of its substantially conical shape, supported by the reln-' forcing member 4, is relatively stiff, and therefore resistant. Thus, the movement is communicated to the annulus rtion D wlnch is flat and relatively thin, ahd although the vibratory eifort 1S applied at the ing movement takes lace in the annulus D, gradually decreasmg inthe direction of the reinforced central areas- In connection with the functioning of the above described construction, the cork ring nal,

shown in Figure 2 first applied to the center on F of raduated cross section is of much praccreases in thickness toward its inner edge, and also being elastic, it causes a more graduniform flexing, thereby tending to avoid the formation of partials, and also by reason of its soft nature, tending to further prevent the formation of partials.

B the use of this ring instead of a pad or disk covering the entire central portion, the tendency to mullle the sound is avoided.

It will, of course, be understood that va-i rious minor 'ohan es may be resorted tofu constructing the iaphragm, but in all cases the primary features of making the central portion of the diaphragm offset or bowed,

, in one form 'oranother, n combination with a reinforcingmember 4 and the ring F, of suberous material is preserved to carry into efiect the objectsought to beattained by the present improvement. 1 5 As illustrating the range of such modifications, reference may to 9, inclusive of the drawing, whic show varying forms of thecentral portion'ofrthe diaphragm which maybe used without de parting vention; r

, Figures 6, 7, 8 and '9 show more particularly what may be termed a compound oil" setting of the -"ci'antral portion D' of the diaphragm, the same being ollset to both sides of the plane of the annulus D. That is to say, the central portion D of the dia-' phragm I) in Figures'tl, 7, 8 and 9 is'more or less ahrupgly de ressed or ofi'set as indicated at T us arrangement gives added strength, andserves to better resist the tendency of the diaphragm itself to warp.

'From the foregoing it features and advantages provement will be readily apparent to, those skilled in the art, and it will of"-course be understood that further chan es in the form, propoi tion and minor detai s of construction may be resorted to without departin irit of the invention or scope o is thought that the from the s the appen ed claims."

I claim; f 1. A construction for reproducerdiaphragms cdmprisinga resilient body disk having a central unpadded ofiset portion and an-unpadded'outer edge portion, and a rin of suberous material secured to' one face 0 the body disk adjacent the edge of the olfset and disposed inside of the unpadded outer edge portion. I V

2. construction for reproducer diaphragms comprising a resilient body disk having a central, unpadded offset portion and an un added outer ed e portion, and a ring of Sn rous material, iaving atapered crow section, secured to oneface of the body from the spirit or scope of the of the present im--.

disk adjacent the edge of the offset and disposed inside of the unpadded outer edge portion.

3. A construction for reproducer dia- 6 phrugms comprising a resilient body disk having a central unpudded ofi'se't portion and an unpadded outer edge portion, a reinforcing plate secured to said ofl'set portion, und ring of suberous material secured to one face of the body disk adjacent the edge 10 of the ofl'set and disposed inside of the unpaddedouter edge portion.

In testimony whereof I hereunto afiix my signature in the presence of two witnesses. CHARLES E. SEMPLE, JR. Witnesses:

LEILA C. Aoovs'nue, Mum, Scnmrcx.

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