US1403849A - Sotjnd-reprodttcing diaphragm - Google Patents

Description

P. B. DELANY. SOUND REPRODUCING DIAPHRAGM. APPHCATION mm ocr. 1920.

W/gVENTOR M AITORNE UNITED STATES PATENT oFricE.

PATRICK B. DELANY, OF SOUTH ORANGE, NEW JERSEY.

SOUND-REPRODUCING DIAPHRAGM. I

Specification of Letters Patent. Patent-ed 17,- 1922.

Application filed October 1, 1920. Serial No. 414,112.

and claimed a laminated diaphra consist in'g of layers of paper or other br'ous-m'aterial alternating with-layers'of permanently flexible adhesive material, the whole assemblage being' clampe'd between rigid or nonyielding gasket members. Diaphragms of this type have given eatly improved results as compared with the ordinary mica diaphragm particularly in the excellence of rendition of musical tones unaccompanied by extraneous metallic sounds characteristic of the use of mica diaphragms. In the course of continued experiments conducted for the purpose of obtaining, if possible, still more perfect results, I have discovered that a greatly improved laminated diaphragm can be formed of layers of fibrous or other material alternating with layers of a viscous substance, such as Vaseline, in which the factor of adhesiveness is largely replaced by a lubricating characteristic and which not only permanently retains a pronounced yielding or pliant capacity but also renders the diaphragm, as a whole, impervious to moisture.

I do not confine myself to the use of any specific material to the exclusion of other materials and I find that excellent results can be obtained by the use of layers of mica, metal or glass alternating with films of vaseline, castor oil or other similar materials of animal, vegetable or mineral origin, or combinations of such materials, the assembled diaphragm being clamped between yielding gaskets. When sheets of fibrous material alternating with viscous substances are used, I prefer to clamp the diaphragm formed between non-yielding gaskets of metal, hard rubber, celluloid or the like. I find that diaphragms of either one of the two general forms referred to are greatly superior to the ordinary solid disk diaphragm formed of mica. in that the normal resonance and metallic ring of the ordinary diaphragm are wholly overcome,

there is almosta complete eliinination of scratching and other-extraneous sounds. In addition, .there is v developed amarked mellowness and human quality. to vocal tones and a harmonious blending of svmpathy. in- I strumentation. I t

I attribute-the-superior results. obtained to an increased degree-of flexibility of the thin layers of nateria'l between whicln the material to, at least, prevent the absorption of moisture by the disks.

In order to exclude air from the viscous substance between the disks comprising the diaphragm, I arrange to clamp the disks together tightly at their central as well as at their peripheral portions. thereby an annular air-tight receptacle or series of receptacles for the substance as will be clear, and which will preserve the material for an in definite period of time unimpaired.

In the drawing:

Fig. 1 shows in cross-section a diaphragm formed of two disks of thin mica with an interposed layer of viscous lubricating material.

Fig. 2 shows a similar view of a diaphragm formed of four layers of paper alternating with lubricating material.

Fig. 3 shows a composite diaphragm such as is shown in either Fig. 1 or 2, clamped to gether both at the center and at the periphi ig. 4 shows a composite diaphragm formed of sheets of fibrous material placed in immediate contact with each other.

In Fig. 1 of the drawing there is illustrated a diaphragm formed of two thin sheets of mica 1, with an interposed layer of lubricating material 2, such as Vaseline. Fig. .2 shows a similar structure in which sheets of paper 3 or other fibrous material vibrating arm of .viscous substance, is .spre'adiand the conse- -quent.damping. of inherent resonance the -case of mineral? or hand; disksas well as to the increased flexizlziillity 'owingto the lubricationEqfithe' disks, .ingthei-rfbowed flenation. under :thef-actionwt 1 the alternate with films of Vaseline 2. I have found a tough-fibred writi paper or .WEZLP- ping paper well adapted? this purpose. As has been already indicated, the composite diaphragm thus produced is much more pliable and sensitive than a solid diaphragm of the same thickness, owin' to the freedom of movement of the disks re ative to each other as contrasted with the strains and compres sion efi'ects on the outer surfaces of the solid or unitary type of diaphragm.

In Fig. 3 of the drawing there is shown a clamping arrangement in which the central as well as the peripheral portion of the diaphragm is clamped or compressed to thereby produce a sealing effect which will prevent the access of air to the lubricating material and thereby maintain the material indefinitely against deteriorationQ As already indicated, the-amount of lubricating material employed may be very small and may even be wholly omitted in certain cases. InFigJl of the drawing there is shown a diaphragm -formed of a plurality of sheets of fibrous-material such as paper, the sheets or disks being clamped into intimate superficial contact with each other,

without making use of either adhesive or lubricating material between the disks.

What I claim is:

l. A diaphragm formed of a plurality of layers of mica with a lubricant therebetween, the mica being clamped together at its periphery and also near the center to preventaccess of air to the lubricant.

2. A diaphragm formed of a plurality of layers of mica with Vaseline therebetween, the mica being clamped together at-its periphery and also near the center to prevent access of air to the Vaseline.

3. A diaphragm for sound boxes comprising a plurality of layers of normally resonant material with a lubricant therebetween, whereby normal resonance is overcome, the layers of material bei-n clampecl 'together at their periphery and a o near the *center to prevent access of air'to the lubricant 'Signed at Nantucket, in the countyio f Nantucket a-nd -State of Masaohusetts, this 13th "day of Septem-hery1920.

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