US1246552A

US1246552A - Acoustic diaphragm.

Info

Publication number: US1246552A
Authority: US
Inventors: Clarence F Cookson
Original assignee: ROBERT L MCELROY
Current assignee: ROBERT L MCELROY
Priority date: 1917-03-19
Filing date: 1917-03-19
Publication date: 1917-11-13
Anticipated expiration: 1934-11-13

Description

c. icooxson. ACOUSTIC DIAPHRAGM.

y APPLICATION FILED MAR. I9 19H.

1,246,552. mmm Nov. 13', 1917.

wnessfs) a; :Mmm Lv' 'larenceil.

UNITED STATES PATENT OFFICE..

I CLARENCE F. COOKSON, OF BROOKLYN, NEW YORK, ASSIGNGR TO ROBERT L. MGELRO'Y',

0F NEW YORK, N. Y.

ACOUSTIC DIAPHRAGM.

Speccation of Letters Patent.

Patented Nov. 13, 1917.

To all whom t may concern:

Be it known that I, CLARENCE F. Cooxsotv, a citizen of the United States, residing `1n Brooklyn, in the county of Kings and State of Newr York, have invented certain new and useful Improvements in Acoustic Diaphragms, of which the following is a speelcation. This invention relates to improvements 1n diaphragms and the method of making the same, and more particularly to such a diaphragm for a phonograph constructed of a laminated fabric. Preferably two layers of vellum or other parchment are employed, between which is a plurality of layers of tissue paper having one side coated with an adhesive substance providing means for unitingthe layers of tissue and for securing one of .the layers of vellum on each side thereof. Diaphragme constructed of metal, mica and paper have. been heretofore employed, but it has been long recognized that such diaphragme have a relative slow recovery,

which will not permit the needle actuated thereby to contact with all the minute variations of the sound grooves of'a record. The present improvement, however, consisting ofa laminated fabrica diaphragm, has a very rapid recovery causing the needle to contact with every variation of groove on the record, no matter how Aminute, thereby developing accurate reproduction and a greater' resonance. Y

*Another object of the present invention, is to devise a simple and inexpensive method of making the laminated fabric diaphragm.

A still further object of the present improvement, is to devise aiphonograph diaphragm which is constructed of cheap ma` terial and which may be manufactured at minimum expense.

Other objects and advantages of the present improvement will be set forth in the following description, one embodiment of which is illustrated in the drawings, in which: c

'.Figure 1, is a ldiagrammatic view of an apparatus for making sheets of laminated fabric and stamping diaphragms therefrom.

Fig. 2, is a side Ielevation of one ofthe completed diaphragms. Fig. 3, is a side elevation of a diaphragm showing the layers lof fabric composing it pulled apart.

Fig. '4 is a diagrammatic view of a sound wave on a record and illustrating the difpressing machine.

ference in the actionv of a needle operated in4 conjunction with a laminated fabric diaphragm and a needle operated in conjunction with a metal, mica or paper diaphragm.

eferr-ing now tb the drawings in detail, in which like reference/ numerals designate similar parts, throughout the several fig; ures; 1 represents a suitable framework at one end of which eight shafts are mounted in spaced relation and one above the other. These shafts are numbered 2 to 9 inclusive on the drawing. A roll of fabric, preferably vellum, 1.0 is revolubly mounted on the shaft 2, the free end of which is passed between a roller 12, and 'a roller 13, which latter roller has its lower portion arranged to dip esy within an adhesive substance 14, carried shafts 3 to 8, respectively, the ends of the tissue paper 16 being passed between contacting rolls '22 and 23, the roller 23 dipping within an adhesive substance carried Within a receptacle 24, the said

rollers

22 and 23, and receptacle 24 similar to and arranged directly beneath the receptacle 15. The end of the tissue paper 16 is then led beneath a guide roller 25 and thence'to the The other live rolls of tissu-e paper have their free end passed through similar devices for coating theirr 95 these devices being numbered'26 to 30, which under surface with an adhesive substance,

operate upon the tissue paper rolls 17` to' 2l, respectively. The ends of these rolls of tissue paper are also lcd beneath guide rolls i numbered 3l to 35 respectively and thence to the pressing machine. A second roll of vellum 36 is revolubly mounted on the bottom shaft 9, the' free end of which does not pass through an adhesive coating device but' and passed between two rolls 38 and 39 re' volub'ly mounted upon shafts 40 and 41, carried in a'framework 42. 1t will be noted that all the layers of tissue paper are arranged one on top of the other and between the layers of vellum, and that the under surface of the sheet of vellum 2 and of all the sheets of tissue are coated with the adhesive substance 14. applied thereto by means ot' the applying devices heretofore described.

The sheets of tissue and vellum upon passing through the rolls` 38 and 39 are pressed together by spring tension accomplished by means of springs -l3 strained between set screws 44 and t-he shaft 40 which is vertically movable in a slot 45. Heat is applied to the laminated sheets by means ot a suitable heating medium 46 contained within the roller 39. Upon leaving the rollers 39 and et() the laminated sheets have been all secured together by the adhesive substance and the said adhesive therebetween dried. The unitary structure 47 then passes between a female die 48 having a plurality of openings 48 therein and a plurality of cored male dies 49 the cores of which are the desired size of the diaphragm. The male dies 49 are forced downwardly by any suitable means, entering the openings 48 in the female'die 48 cutting out a plurality of completed diaphragms 50, which drop within a collection receptacle 51.

The adhesive substance used within the coating devices may be gum, resin, paratlin wax, shellac, varnish or any resinous gum.

Diaphragms constructed of metal, mica or paper have in practice demonstrated that they have what is know as a slow recovery. This means that the needle upon being moved and released by a sound groove will not be returned quickly to its original position by the diaphragm for contact with the neXt portion of the sound wave of the groove.

In Fig. 4 a portion of sound wave is illustrated at 55 which has a large curve 56, a number of small curves 57 and another large curve 58. A needle 59 is illustrated as just leaving the large curve 56. When this needle is controlled by a mica, metal or paper diaphragm, upon being moved by the curve 5G will recover so slowly that the small waves 57 will be skipped in the rapid passage of the record and the needle strikes the second large sound wave 58 as is illustrated in dotted lines at 60.

When the needle 59 is controlled by a laminated diaphragm, however, upon being struck by the large curve 56 will be returned to its original position so quickly by the diaphragm that it will slide down the slope 5G of the large curve 56 and pass over all the small curves57 as is illustratedvinA dotted lines at 61.

The laminated diaphragm will interpret all the phrasing of the notes which the ing apparatus, comprising a plurality of interposed layers of relatively thick and relatively thin fabric homogeneously secured together into a composite single sheet, the tivo outer layers being thicker than the inner layers.

2. A diaphragm consisting oi' two layers of vellum, a plurality of layers of tissue paper therebetween, and an adhesive substance uniting the vellum and tissue.

$3. A diaphragm consisting of two layers ot vellum, a plurality of layers of tissue paper therebetween, and an adhesive substance applied to one side ofl the vellum and tissue paper for uniting them.

il. A diaphragm for use in. sound transmitting, receiving, recording, or reproducing apparatus, comprising interposed layers of relatively thick fabric and layers et relatively thin fabric, the thin fabric being 'oit a. dilerent material than the thick, and an adhesive substance applied to one surface of each of the layers for securing them together.

5. A diaphragm consisting of two layers of relatively thick fabric and a plurality of -layers of relatively thin fabric therebetween, and an adhesive substance uniting the said thick and thin layers of fabric.

6. [i diaphragm consisting ot a plurality of interposed layers of vellum and tissue paper secured together.

7. vdiaphragm consisting of two layers of relativel thick fabric and six layers of relatively tliin fabric therebetween, and an adhesive substance uniting the layers.

8. A diaphragm consisting ot two layers of vellum, six layers of tissue therebetween, and an adhesive substance uniting the vellum and tissue.

9. A diaphragm consisting of a plurality of interposed layers oit vellum andtissue paper and an adhesive substance for uniting them.

10. A diaphragm consisting of a plural' vellum and layers ot tissue paper secured thereto.

Clie RENCE F. COOKSN. Witnesscsz H. A. ParrrsoN, H. D. PENNEY.