US375315A - Mechanical telephone - Google Patents

Description

(No Model.)

W. H. EASTMAN 8: D. J. ADAMS.

MECHANICAL TELEPHONE.

-No. 375,315. Patented Dec. 20, 1887.

WILLIAM H. EASTMAN AND DAVID PATENT OFFICE.

J. ADAMS, OF CONCORD, ASSIGNOBS, 9

BY MESNE ASSIGNMENTS, TO THE EUREKA TELEPHONE COMPANY,

OF NASHUA, NEW HAMPSHIRE.

MECHANICAL TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 375,315, dated December 20, 1887.

Application filed May 4, 1887.

To all whom it may concern:

Be it known that we, WILLIAM H. EAST- MAN and DAVID J. ADAMS, citizens of the United States, and residents of Concord, in the county of Merrimac and State of New Hamppose set'forth, with the receiving-diaphragm, I

of two conical diaphragms of thin sheet indiarubber, having their apexes in proximityito the center of the receiving diaphragm arranged nearly parallel to each other, separated by an ai rchamber,and stretched over a wooden ring surrounding the conducting-wire.

In the accompanying drawings a telephone is shown which embodies the principle of our invention, and Figure 1 is a back view of this telephone, showing the back board removed. Fig. 2 is a front View of the telephone. Fig. 3 is a sectional view.

In these several figures the same letters refer to the same parts.

We have represented our improved diaphragm and its attachment as used with a telephone-case of the box form; but they may be used with any other form of telephone-case.

Referring to the drawings, A is the diaphragm attached at its edge to a wooden frame, B, forming the front of the case and attached to a series of wooden posts. The sides of this case are formed of pieces of thin wood, 1), attached to these posts, and the back of the case is also formed of a piece of thin wood, E, se-

cured to the posts, and having a perforation in its center through which the conducting-wire passes. This manner of constructing the case forms no part of our invention, and it may be made in any manner by which a chamber will be formed in the rear of the receiving-diaphragm. This diaphragm is preferably dished, orof conical form, and is preferably made of Serial No. 237,035. (No model.)

drum-head parchment. A sheet ofthin indiarubber is stretched over the outside surface of the diaphragm, and is preferably made adherent to it. The effect of this rubber covering is to destroy the resonance of the parchment diaphragm, and thus prevent confusion of sounds and improve the articulating-power of the telephone. not claim in this specification; but it may form the subject for another application for a patent.

F is the conducting-wire, attached to a button, G, at the center of the diaphragm and passing through the same. The button which we use is preferably made of lead, and is sepaber, leather, or other similar sound-deadening material. Supported within the case about an inch from the receiviug-diaphragm,by wires ring, H, of less diameter than the receivingdiaphragm, and c c are two nearly parallel diaphragms of thin sheet india rubber, which are stretched over this ring,- and are separated from one another by an air-chamber. The rear one of these two diaphragms has at its center a metallic disk, I, preferably of lead, through which the conducting'wire passes. This disk is brought almost into cont-act with the back of the receiving-diaphragm A, after the proper tension has been given to the same, and is then suitably fixed upon the wire. In this way, and in addition, owing to the strain caused by the tension of the receiving-diaphragm A, the rubber diaphragms are caused to assume a conical form and to be maintained in a tense condition. The action of this device is to prevent the effect upon the receiving-diaphragm A of the longitudinal and transverse vibrations of the conducting-wire due to its resonant property and to the effect of wind, and thus prevent the roaring and ringing sounds which interfere with the perfect transmission of sounds by the molecular vibration of the conducting-wire, thereby enabling the instrument, as has been found by experience, to transmit speech with distinctness for distances much greater than is usually possible with mechanical telephones.

Having thus described our invention, what This form of diaphragm we do rated from the diaphragm by a washer ofrubattached to the walls of the case, is a wooden we claim, and desire to secure by Letters Pat- In witness whereof we have hereunto set our ent of the United States, is-- hands in the presence f the two subscribing The combination, substantially as and for witnesses.

the purpose set forth, of the diaphragm A, the

5 c0nducting-wire F, the button G, the disk I, WILLIAM H. EASTMAN.

the ring H, supported within the telephone- DAVID J. ADAMS. case, and the conical tense diaphragrns of thin sheet-rubber c a, stretched over said ring and NVitnesses: separated from each other by an air-space, sub- ALEX. L. HAYES, IO stantially as and for the purpose set forth. J. E. MANNING.

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