US1033086A - Differential microphone-transmitter. - Google Patents

Description

J. J. comm, DIFFERENTIAL MICROPHONE TRANSMITTER.

APPLIOATIONIILED OUT. 24, 1910. v

Patented July 23, 1912.

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Y J .'J. GOMER. I DIFFERENTIAL MICROPHONE TRANSMITTER.

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atented July 23,1912:

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WI /E5553 Jenn J. comes, on CHICAGO, ILLINOIS, Assrenon'ro AUTOMATIC-ENUNCIATORW:

COMPANY, OI! CHICAGO, ILLINOIS, A CORPORATION OF ILLINOI DIFFERENTIAL MIcnorHonE-TRAnsMrrTER. r

Specification of Letters Patent.

perennially 23, 1912.

Application filed October 24, 1510. Serial at. 588,788.

To all whom it may concern? Be it known that I ,'JO IIN J; COMER, "a citizen of the United States of America, andresident of Chicago, Cookcounty, 'Illinois, 'haveanvented a certain .new and useful In'iprovement in Differential 'Microphone- .lransmitters, of which the following is a specification.

My invention relates to transmitters of the kind ordinarily known asdilferential transmitters. Theobject of my invention is to provide an improved construction and arrangement whereby the plunger or intermediate electrode 'ofa transinitterof this kind is heldstationary between two movable electrodes.

[In this wayI combine the agit ation'or shaking of. the carbon granules with the differ-1 ential principle of transmission in' a microphone in which at least one of the electrodes is stationary. Such atransmitter is, I find, especially adapted for use in loud speaking systems, or in systems forloud transmission,

such, forexample, as those employed for music or other similar purposes, it being es sential in such cases that the enunciation and tone be clear and. pure, and it being necessary very often, in order to obtain these results, to use heavy currents, or: at least currents much =tooheavy for the ordinary showing another form of my invention.-

Figs. 7, 8 and 9 are similar views showing still a thirdform of my invention;

As'thus illustrated, and referring to Figs. 1 to 3 inclusive, the transmitter comprises the front plate A having an opening therein forthe usual mouthpiece B. I The 'diae phragm O is seated against ashoulder a on the inside of said" plate, and'insulated,

therefrom, as shown, and heldin place by a disk D which is in electrical contact therewit'h. Said disk is provided with a central aperture (Z and is, held in place by a clampand is, ther ing rin'g E, that screws into said plate A,

and disk whereby the diaphragm and disk are insulated from the plate A, in themam ner shown. A' sheet metal boxorcu ,I! has its mouthoropenend provided with there being insulation between the said ring aflange f which is secured to the b'ack of the diaphragm C, todorin aamicrophorie chamber for containing the'front and back electrodes f and f and. the granular carbon f- The sald -fro'nt electrode is'secured byla l1ollow rivet-f* to the diaplira'gnniand the Stud back electrode is secured-by a hollow The granular carbon f is insulated from the box F by acylinder of mica "The fined or stat onary electrode f 'i's secured'toa stem] f and interposed between thetwdmovable' electrodes,-bcing in the nature of a plunger. Th s stem-extends v tl1 ro'u, 3;h the rivet f and 4 1s adjustably secured to the bridge f, which rivet f to the back wallfi of thebox F, be-

' ing separated therefrom by a disk of mica f I latter-is secured to the disk D but insulated I therefrom. Fluffy asbestos is used for fill,- mg the holes i-n the rivets ffand 'f, to pre-' ve'nt the granular carbon from escaping, the

opening in the rivet f being used for filling the box-that 1s, for nitrodu'cmg the -.said

granular carbon after the parts are all as sembled. The circuits for said electrodes I may be of any suitable cl'iaracter. As shown, one terminal wiregoes-to the disk D, to thereby in etfe'ctconnect with the front electrode f another' oes to the screw that is secured to the back electrode f and the third'wire-connectswith the bridge f tovthereby connect with the electrode fh' 'lVhen operated differentially, Ijfi'nd that the .above described microphone transmitter will produce goodresults with heavy currents,

in loud-speaking. systems.

efore, especially adapted for:use

In'Figs. -ft to 6 inclusive, the construction I substantially the same as that previously described, except that in this case the microphone box' or cup G -.has the integral end wall g thereof secured to-the diaphragm,

and-the open rear end of said box or cup 15- closed by a cap 9 of flexible sheet metal.

i In Figs. 7 to 9, inclusive,'the construction is in effect the same as that shown in Figs. I 1 to.3,'except that the microphone box 11 is disposed in an opening in the center of the diaphragm, and is.formed by two cups or. halves it and it that are secured to opposite sides of the diaphragm to cover said opening'and form a chamber between them, Thus it- Will be seen that I provide -a microphone box that 1s secured to the d12- -pl1r2\gm, and that-t-l e mode of operation isv such that the said box, althoughpreferably made of sheet metal. does not need aflexible wall or auxiliary diaphragm, both" the front and back electrodesmove by reason of the flexibility of the single lE -rge' and usual diaphragm. while the middle or intermediate electrode remains fixed. or .statioriarj to increase tl e resistance first on one side-thereof and then on the other.

What I claim as my invention is:

1. In a transinitterya diaphragm, "front and back electrodes carried by and movable w th saiddmpliragm, a stationary electrode between saidfront and back el'ectrmles, a support, :and a connection, from said sin-- tionaryelectrode to said'snpport l 'WlllCll con- I nection is secured tojsaid support.-

2. 111 a transmitter, a diaphragm, a' support, a differentialmicrophone box carried on-sziid 'diaplirag ire icl movable therewith, a connection extending lIlSldQ of said box,

and .meansbfor securing said connectionto said support.

3. in a transmit-tenedizrpliragm, a diiy ferential microphpnebox mounted on and momblewith said diaphragm, adisk for clamping said diaphragm in place a bridge on said disk, and a connection-secured 'to sdid bridge and extending inside of said extending through one of said movable electrodes to saidstationary electrode o. In a transmitter, a vdiaplimgm, a" difiierential microphone lion mounted on and movable with said d aphragm, asnpport, a

connection extending inside of said micro phone, and .means for adpistably securing said connection; to said support;

- Signed ,b v me at t liicago, Illinois, this 12th day of October; 1910. v

JOHN J."CO1\'IER. W it-nesses he B. DURNION, ,E. H. CLEGG..

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