US1524689A - Diaphragm for sound-recording and sound-reproducing instruments - Google Patents

Description

Feb. 3. 1.925.

W. E. CLIFTON DIAPHRAGM FOR SOUND RECORDING AND SOUND REPRODUCING INSTRUMENTS Filed Nov. 12, 1921 certain Patented Feb; 1,925.

`.,UNITED STATES 1,524,689 PATENT OFFICE.

'WILLIAM ERNEST CLIFTON, 0F `NOTTIN'GrHAIM, ENGLAND, ASSIGNOR T0 CLIFTOPHONE LIMITED, 0F LONDON, ENGLAND.

p DIALPBAGM FOB SOUND-RECORDING AND SOUND-REPRODUCING INSTRUMENTS.

' Application led November 12, 1921. Serial No. 514,592.

]ect of the invention is to provide an imv proved means of connection between the inner end of the stylus-bar and the diahragm. 4

Hitherto the inner end of the Stylus-bar, the outer end of which is litted with the needle, has generally been attened and secured to the diaphragm by means of a small nut and bolt passing .through the attened end of the stylus-bar and the material of the diaphra in a direction substantiall normal to t e plane of the diaphragm. t has been found in practice that after the diaphragm has been in use for some time a jarring noise often becomes apparent l ,which is now believed to be due to a loosen- `ing of the connection between the stylus-bar and the -diaphra According to t e resent invention there is rovided, on one ace of the diaphra a ug or lugs which project from the iaphragm at right-angles to the surface thereof and to which the stylus-bar is,

or is to be, connected. Conveniently a strip or strips of material are secured to one face of the diaphragm with a portion of the strip or of each strip projecting through an orifice in the diaphragm so as to extend at rightangles to the surface of lthe latter on the opposite si\de of it from that to which'the strip or strips are secured, the projecting portion or portions affording the lug or lugs aforesaid.

According to another feature of the invention a metallic'or other hard member is-provided in contact with, or integral with, the inner end of the stylus-bar and extending towards the diaphragm up to or beyond the plane of the outerI face of the latter, that is to say that face of the latter which is adjacent to the stylus-bar.

By the term hard as applied to the above-named member is meant a characteristic of the material of the member which is hard in comparison with a substance like the libre of the lugs to be described hereinafter. Hard does not lnecessaril mean metallic hardness asfit may be har in the sense that box-wood or lignum vitae, for example, are hard.

Conveniently the hard member extends completely through the diaphragm with its end exposed to the atmosphere beyond the inner face of the diaphragm, that is to say the atmosphere within the sound-box.

rlhe invention will be more clearly understood from the followi description given by way of example o y, of .a preferred manner of carrying the invention into effect and read in conjunction with the accompanying drawings, in which- Figure 1 shows a front elevation of a part of the diaphragm and the stylus-bar;

Figure 2 is a section on an enlarged scale through a part of the diaphragm only on the line 2 2 of Figure 1;

Figures 3 and 4 are views similar respectively to Figures 1 and 2 of a modified form of diaphragm;

Figure 5 is a view similar to Figure 1 of a further modiication; and

Figuresl 6-9 illustrate, on an exaggerated scale, sections through a diaphragm and stylus-'bar connection -of further modified constructions according to the present invention Like reference numerals vindicate like parts in the several figures of the drawings.

In Figures 1 and 2 a simple diaphragm is illustrated as comprising a disc 1 of 'any preferredyielding material, such as is suit.'- able for diaphragms of this nature. The diaphragm 1 is as usual, secured within a sound-box casing indicated at 2. To the back or inner surface of the disc 1 are Secured two strips 3 of material such as libre or Celluloid, the adjacent extremities of which project at right-angles at4 through an orifice in the material of the diaphragm so as to extend beyond its front or outer surface.' The parts 4 constitute two lugs between which the inner end of the stylusbar 5' is received and to which it is secured by means of a transverse pin 6 having at one end a head 7, and at the other a nut 8 cooperating with the screw-threaded-ex-tremty of the pin 6. By means of the nut 8 the lu s in the stylus-bar end can be clamped tig tly together.

In Figures 3 and 4 the connection between the inner end of the stylus-bar and the diaphragm is eli'ected through the medium of the strips 3 having lugs 4 which project through an orifice in the diaphragm. In this illustrated application of the invention, however, the diaphragm 1 is stiEened by additional strips 9 and 10 applied -to the same sides of it with their inner extremities abutting at the centre line of the disc 1. Over the strips 9 and 10 is secured a cover 11 of Celluloid which completely encloses the strip. The strip 3 is secured in this case over the cover 11 as shown clearly in Figure 4.

It will be seen that the diaphragm illustrated in Figures 3 and 4 is of the construction such as is described in my co-pending application Ser. blo/514,591, tiled Nov. 12, 1921, the invention is equally applicable to diaphragms constructed according to my prior applicationSer. No. 47 9;?79'or in fact to any type of diaphragm employed in .apparatus of the class to which the present invention relates. y

In place of the two separate strips 3 as illustrated a single strip of material having a looped portion folded back on itselfto take .the place of lugs 4 could be employed, withthe inner ends of the stylus-bar secured either between the trwo laps of the loop or in contact with the outer surface of one of the laps of the loop.

Instead of forming the inner end'of the stylus-bar with a flattened portion as illustrated in Figures 1-4 to be received between or in Contact withl lugs such as 4, the inner extremity of the stylus-bar can, as shown i-n Figure 5, be bifurcated so as to receive between the two arms thus provided, the lugs such as 4` the two arms of the stylus ends and the lugs being secured together by a transverse pin similar to that illustrated.

It is found that with the present construction the tendency to loosening at the connection of the stylus-bar with the diaphragm is largely, if not completely eliminated, andthe jarring noise referred to as appertaining to constructions at present generally in use is also largely, if not completely, eliminated.

In the construction illustrated it is found that the strips 3 or their equivalent, owing tothe central division constituted by the formation of the lugs, will impart to the stiffening strips 9 and 10 a tendency to bend or flex along adiametral line crossing centrally through the' stiffening strips'parallel with the stylus-bar.

It is obvious that while the invention may be applied to any preferred form of diaphragm it is not necessary that the lugs 4 should be constituted solely in the manner illustrated. For example, a lug or lugs simadditional to the transverse screw securmg' the parts together, or in Some instances, if t'he paste is sulicientlv adhesive. it may be employed as the sole means of connecting the stylus-bar with the lug or lugs such as 4.

In Figure 6 the diaphragm 1 has preferably secured to it,'as before, strips such as 9 and 10, a cover 11 and other strips 3 formed with lugs 4 :projecting from the diaphragm from back to front. The inner end of the stylus-bar, that is the end connected to the lugs 4, is of such length as to pass between them so that its inner extremity terminates approximately flush with the back of the strips 3 and is exposed to the atmosphere within. the sound-box easing. The stylus-bar'and lugs'are secured by means of bolts and nuts 7 and 8 or their equivalent, as inthe previously described constructions.

In Figure 7 a similar construction is shown with the exception that the extremity of the stylus-bar is not tapered.

In Figure 8 the inner end of the stylusably extends tol a position through and between the lugs 4 to be exposed within the sound-box casing.

It is not necessary that the stylus-bar or the members such as 12 be extended completely through the diaphragm as the invention contemplates a hardmember extending either upto or beyond the plane of the outer face of the diaphragm and formed either as an integral extension of the stylus-bar,

v as illustrated in Figures 6 and 7 or as a separate member. For example, in the construction illustrated in Figure S the member 12 may be dispensed with when the stylusbar will terminate approximately on a plane containing the front or outer face of the diaphragm. The dimensions of the parts will be such that the lugs 4 are held tightly to ther.

many of the constructions the hard member ma be tapered in the manner in which the sty us-bar itself is tapered in Figure 6. Preferably the tapering is from a thiclmess of approximately ten to twelve-thousandths of an inch down to from three to fourthousandths of an inch.

When the hard member is non-tapered it is found that a Strip of metal such as tinned iron of from three to four-thousandths of an inch thick andapproximately one-eighth of an inch in width will give a successful result with, for example, a diaphragm of two inches diameter andlsay teli-thousandths of an inch thick.

In place of providing an additional hard member this may be constituted by a metallic coating applied, for example, mechanically or by electro-deposition as a thin layer to the inner surface of one or each of the lugs 4.

What I claim as m invention and desire to secure by Letters atent is 1. In a diaphragm of flexible and substantially non-resilient material for sound-re- -cording and sound-reproducing instruments,

at least one stiiening element superimposed on said diaphra in the region of its central portion an secured thereto, two-lu extending from the outer face of the diaphragm and at right angles thereto and each constituting part of a strip which extends transversely over the aforesaid stiffening element, and means to secure the inner end of a stylus-bar between said lugs, substantially as described.

2. In a sound-box of the type specified, the combination of a diaphragm, articulating means projecting from the outer face of the diaphragm at right angles thereto, a stylusbar havlng its inner end connected by Asaid articulating means tothe diaphragm, and a.

hard member additional to the articulating means extending at one end towards the diaphragm at least up to the plane of the outer face thereof and at the other end forming a close-contact co ection with the inner end of the stylus-bar, substantially as described. l

3. In a sound-box of the type specified, the combination of a diaphragm, articluating means projecting from the outer face of the diaphragm at right angles thereto, a stylus-bar having its inner end connected by said articulating means to the diaphragm, and a hard member additional to the articulating means and extending at one end completely through the diaphragm, whereby said end is exposed to the atmosphere beyond the inner face of 'said diaphragm, and at the other end forming a close-contact connection with the inner end of the stylus-bar, substantially as described.

4. In a sound-boxof the type specied,

the combination of a diaphragm, articulating means projecting `from the outer face of the diaphragm at right angles thereto, a stylus-bar having its inner end connected by said articulating means to the diaphr and a hard member additional to the articulating means and extending at one end at least up to the plane of the outer face of the diaphragm, said end being exposed to the atmosphere beyond the inner face of said diaphragm, and at the other end forming a close-contact connection with the inner end of the stylus-bar, said hard member being in the form of a flat strip whose dimension 1n a plane parallel with the length of the stylus-bar and normal to the plane of the diaphragm is large in comparison with the thickness thereof, substantially as described.

l 5. In a sound-box of the type specified, the combination of a diaphragm, articulating means projecting from the outer face of the diaphragm at right angles thereto, a stylusbar having its inner end connected by said articulat' g means to the diaphragm, and a hard member additional to the articulating means and extending at one end at least gs u to the planeof the outer face of the diap ragm, said end being exposed to the atmosphere beyond the inner face of said diaphragm, and at the other end forming a close-contact connection with the inner end of the stylus-bar, said hard member being wedge-shaped and tapering towards that extremity of it which approaches the diaphragxlxli, substantially as described.

6. asound-box of the type specified, the combination of a diaphragm, two lugs extending efrom the outer face of the diaphragm at right angles thereto, a stylus-bar, the innerv end of which is secured between said lugs, and a hard member disposed between said lugs and extending at one end at least up to the plane of the outer face of the diaphragm, and at the other end forming a close-contact connection with the inner end of the stylus-bar, substantially as described.

7. In a sound-box of the type specified, a diaphragm having an aperture in the region of its centre, a stylus-bar vhaving its inner end extending completely through said aperture, an articulating member one end of which is parallel with and secured to the inner face of the diaphragm and the other end of which extends through the aforesaid diaphra aperture at right angles to and beyond iii outer face of the diaphragm, and means for securing the free end of the articulating member to the stylus-bar, substantially as described; f I mx ture Intestimon wereo a m si a i ERNEST oN,

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