US234744A - Microphone - Google Patents

Description

(No Model.)

- E. BERLINER.

Microphone. No. 234,744. Patented Nov. 23, I880.

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UNITED STATES PATENT Grinch.

EMILE BERLINER, OF BOSTON, MASSACHUSETTS.

MICROPHONE.

SPECIFICATION formingpart of Letters Patent No. 234,744, dated November 23, 1880,

Application filed March 31, 1880. (No model.) Patented in France January 8, 1880, in Belgium January 9, 1880, in Italy February 15, 1880.

To all whom it may concern:

Be it known that I, EMILE BERLINER, of Boston, in the county of Suffolk and State of Massachusetts, have invented a certain new and useful Improvement in Microphones or Contact-Telephones, of which the following is a specification, reference being had to the accompanying drawings.

This invention relates to that form of microphone or contact-telephone described and claimed in Letters Patent of the United States, No. 225,790, March 23, 1880, in which one electrode forms part of or is attached to a pendulous weight, which is kept from reaching its point of rest by contact with the other electrode; and the improvement consists, first, in the combination, with said pendulous weight, of an adjusting device whereby its angle of inclination to the other electrode and pressure upon the same can be varied at will; second, in the combination, with the vibrating surface of the microphone or contact-telephone, of an elastic arm to which one of the electrodes is attached, and an adjusting-screw the point of which is in contact with said surface and forms a damper to the same; third, in suspending the pcndulous weight from a magnet which holds the said weight by attraction; and, fourth, in electroplating the surface of the said magnet.

In the accompanying drawings, Figure l is a view, in perspective, of the back of a microphone or contact-telephone containing my improvements herein described, that part of the instrument which contains the induction-coil having been removed, and Fig. 2 is a vertical section through the same.

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

A is the block which supports the vibrating diaphragm B andP is a block of carbon,forming one electrode of the circuit, which block is suitably attached to the center of the diaphragm.

D is an elastic plate of metal, which is fixed at one extremity, by a screw or in any other suitable manner, to the top of the block A, and is free at its other end. This end is made annular, so as to surround the carbon electrode P. A screw, M, passes through the lower end of the plate D and bears upon a piece of soft rubber on the diaphragm B, and by means of this screw the distance of the lower extremity of the plate D from the vibrating diaphragm can be varied at will to any desired extent. The pressure of the end of the screw on the vibrating diaphragm also acts to damp the vibrations of the diaphragm, and it is obvious that this pressure admits of adjustment.

E is a permanent magnet, which is attached to the plate D, and may either be a bar-magnet, as shown, or a horseshoe-magnet.

G is the pcndulous weight, having a carbon tip in contact with the carbon block P, and to this weight is fixed a plate, H, of soft iron, which forms the armature of the magnet E, and is attracted and held to the magnet by its edge, so that it is able to oscillate freely on the same from its point of suspension.

A copper wire, K, may be used for retainin g this weight in position.

One pole of the battery is connected to the plate D by the screw, which is insulated from the diaphragm, and from thence the current passes through the magnet to the carbon electrode on the pcndulous weight, and the other pole of the battery is connected by the metallic strip R to the carbon block P.

By raising or depressing the free end of the plate D by means of the screw M, the angle of inclination of the weight G to the surface of the electrode P and its pressure upon the same can be varied at will, so as affect the contact between the two electrodes as may be desired, to secure the proper transmission of sounds.

It has been found that in microphones or contact-telephones containing a frictional con- 1. A microphone or contact-telephone in which one electrode is held in position by being suspended from or attached to a permanent magnet by attraction, substantially as and for the purpose set forth.

2. In a microphone or contact-telephone, the combination of a vibrating surface, a damper consisting of an elastic arm provided with an adjusting-screw, the extreme point of which bears against the said vibrating surface, and two electrodes in variable contact with one another, which are situated between said screwpoint and the edge of said vibrating surface.

3. In a microphone or contact-telephone, the combination of a vibrating surface forming one electrode of an electric current, a pendulous weight forming the opposite electrode, and a device for changing the inclination of said pcndulous weight, substantially as and for the purpose set forth.

4. In a microphone or contact-telephone, the combination of the diaphragm B, carbon block P, adjustable weight G, plate H, forming an armature-magnet, E, elastic plate L, and adjustii'lg-screw M, substantially as and for the purpose set forth. v

In a telephonic apparatus, a magnet forming an electric contact and electroplated on its face in contact, substantially as and for the purpose set forth.

In witness whereofI have hereunto set my hand in presence of the subscribing witnesses.

EMILE BERLINER.

Witnesses:

OHAs. E. BURLINGAME, ALEX. L. HAYES.

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