US1112167A - Telephone-transmitter. - Google Patents

Description

Vif. L. SPENGE. TELEPHONE TRANSMTTER.

APPLICATION FILED JUNE 6,1913.

Illini narran sierras P iirnnr oFFioE.

JESSE L. SPENCE, 0F NEW YORK, N. Y., ASSIGNOR T0 ELECTICAL EXPERIMENT COMPANY, INC., A CORPORATION OF NEW YORK.

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Specification of Letters Patent.

Application filed .Tune 6, 1913. Serial No. 772,087.

To all'uwm t may concern.' y

Be it .known that I, JESSE L. SrnNoii, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Telephone Transmitters, and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The principal object' ct' the present invention is the production of a telephone tra'nsmitter capable of delivering to the transmitting medium a form of wave more strictly conforming to the acoustic wave to be re produced than has been possible hitherto. The result is materially improved enunciation at the receiving end of the system, which is particularly noticeable in loud speaking telephones.

One of the principal causes of distortion of sounds as iinally received over a telephone is found in the fact that the transmitter diaphragms against which the speakers voice is directed tend to impose an artificial vibratory -law upon the wavel to be transmitted, either. owing tothe-bending of the diaphragm itself or to its attachment to eX- ternal devices so constructed or mounted as to have their own period of vibration. The present improvement avoids Kthese objections by luse of a substantially rigid diaphragm and a mounting for the same of an aperiodic nature, whereby neither the diaphragm itself nor any external part connected therewith tends to impose an 'artiiicialperiodicity upon the resultant wave transmitted.

My improved transmitter may be used upon ordinary telephones, 'or in .connection with wireless telephonie systems.

The accompanyingr drawing is a vertical section of a preferred embodiment of my invention.

`Within the usual casing 10 is placed a conducting cup 11, preferably insulated from the casing where this latter is made of metal, as in the preferred form shown. This cup, is connected to one out-going wire 12, while the .other out-going wire 13 is connected to the, diaphragm, as for instance through the l casing 10 itself, as shown. vWithin the cap 11 is placed the carbon dust or powder, or other microphonic material 14 against which, (in my preferred form) the diathe same when not, iiiuse.

that cushions so used serve as an aperiodic' voice. I

' phragm 15 is made to bear directly. Owing to the fact that-the diaphragm is relatively inflexible, I am able to use a thin plate of carbon in this connection, and thus get the advantage ot' carbon against carbon without resort to anv attachments on the diaphragm. I prefer to inter-pose a soft felt layer 16 between the sides of the microphonic mass or masses and the cup 1l. rlhe conducting diaphragm 15 rests with its edge in contact with the metallic container or casing 10. as lshown in the drawing, and is thereby broughtl into electrical connection with one of the vleading-in wires 13.

preserved by two delicate annular air cushions 17 and 18, preferably of thin rubber,

which make light contact with thefedge of-i the diaphragm and act merely to support I have found I have found that a transmitter.. con structed substantially as described causes a movement of pure translation to be imposed upon the diaphragm 15, thus bringing int-o uniform and eiiieient action all the particles or microphonie masses 14 within the cup 11.

Patented sept. 29, i914.'

I do not con fine myself to this expedient for bringing the diaphragm into the circuit, however. The proper position of the 'diaphragm is This follows from the movement ofthe in- 1flexible diaphragm always parallel to the position of silence.

In certain forms of apparatus hitherto used, air cushions have been employed to clamp al diaphragm irmly in place, for damping purposes. Such a structure has no relation to thepresent invention, wherein a substantially rigid diaphragm isso mounted as to acquire a movement of translation as 'a whole. A movement of this character involves preservation of thevplane form of the diaphragm at all times, and there results a more evenly distributed pressure upon the microphonic material than Where the diaphragm bends in a-curve. This gives better efficiency in the microphone and prevents local packing of the particles near the center, -inaking the microphone more durable.

I do' not limit myself to the details of construction described, as various changes may be made Without departing from the invention. v

WhatI claim is- 1. In a telephonie transmitter, a microphone, a diaphragm sutiiciently stift' to be substantially inflexible under the conditions of-use and mounted in operative relation with said microphone, and a resilient mounting for said diaphragm of an aperiodic character, adapted to permit movements of the diaphragm responsive to the form of acoustic Waves with a minimum of distortion, substantially as described.

2. In a telephone transmitter, a microphone and a diaphragm in contact therewith suiiciently stiff to be substantially inexible under conditions of use; in combination with a resilient aperiodic mounting for said dia hragm adapted to permit moverments o. translation of the same responsive to the impressed acoustic Waves with a minimum of distortion.

3. In a telephonie transmitter, a conducting casing, a microphone Within the same insulated therefrom, a conducting diar.phragm resting on its edge upon and Within said casing, said diaphragm being sufiicient-ly stiff to be substantially inflexible under conditions of use, and a yielding aperiodic mounting for said diaphragm, substantially as described.

4:. In a telephonie transmitter, a microphone, a diaphragm suiliciently stift1 to be inflexible under conditions of use and mounted in operative relation with said microphone, and a pair of delicate air cushions making light contact with the opposite sides of the edge of said diaphragm and adapted to yield readily to the movements of the diaphragm incident to operation, substantially as described.

5. In a telephonie transmitter, a microphonic mass of carbon, a thin4 carbon diaphragm suiiciently stift' to be inflexible under conditions of use in contact with said mass, and a yieldin aperiodic mounting for said diaphragm, su stantially as described.

In testimony whereof', I aiiix my signature, in presence of two Witnesses.

KATHARINE C. MEAD, I-I. S. MACKAYE.

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