US1759898A - Transmitter - Google Patents

Description

l May 27, 1930.-

H.'F.'FRUTH l TRANSMITTER Fi1ed sept. 16. 1926 155:41. All r ldllllldl,

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' Patented May ,27, 1930.

. tions inthe combinedor effective resistances UNITED ls'rfrlzs PATENT/OFFICE HAI. FREDERICK ERI'ITII, OE CHICAGO, ILLINOIS, ASSIGNQR To WESTERN ELECTRIC COMPANY, INCORoRaTEI), -OE NEW YORK, N. Y., .e CORPORATION or NEW YORK TRANSMITTER Application led September 1 more particularly to a variable resistance apparatus for4 telephone transmitters.

The primary object of this invention is to provide a simple, compact and'eiiective current varying means for electrical transmitters. ,f I

In accordance with the general features the invention contemplates the cooperation of a plurality of electrical conductors of different resistance values and differently affected by a vibration responsive means to roduce variathereof. One embodiment of the invention contemplates a current varying device which forms a part of a transmitter circuit and comprises a low resistanceconductor, such Vas a block of suitable conducting material fixed within the transmitter housing and a high re' sistance stripv adapted to make contact in varying degrees with the 'conductor bloc'k.

,The high resistance strip is so connected with the transmitter diaphragm that the vibrations of the diaphragm will be imparted thereto, causing the strip to vary its contact with the low'resistance block, short circuiting portions of the strip, and thereby producing variations v in the combined- Or effective resistance of they' strip and the block 1n accordance with the vibrations of the diaphragm. The invention is capable' of many other applicationsand some alternative forms thereof'are disclosed in the accompanying drawings.

These and other objects will be more apparent from the following detailed descrip'- 'tion and theaccompanying drawings, where- Fig. lis a central, vertical, sectional view of a transmitter provided with a current varying view of the device which is representative of one embodiment of the invention; ,I

' Fig. 2 is a transverse, vertical, sectional transmittertakenon the line 2-.2

ofrFig.1; I A Fig. 3 is acental, vertical, sectlonal view,

of a current varying device which represents A `an alternative-form of the invention;

Fig. 4 isa similar-,sectional view of a curient support for the diaphragm 6, 1926. i .Serial No. 135,7523.v

Fig. 5 is another form of the invention, disclosing a pair of diaphragms coupled with acurrent varying device. ,i Referring now to the drawing wherein like numeralsv have been vemployed .to designate similar parts through the various figures it will be observed that the numeral 10 in ig. 1 is employed generally'to indicate a telephone transmitter. This transmitter comprises a mouthpiece 11 which is threaded'upon a housing 12. Threaded within the housing 412 isa cylindrical ,casing or shell 14 Which-'is `closed at its inner end, its lopposite fend bef l phragm18 of duralumin, aluminum or other suitable material. These .rings 17 may be constructed of felt, rubber or other `suitable l I materialwhich will supply the properresil- 18D n l Acurrent varying means of the, typedis` closed in Fig. lconip'rises a semicylindrical low resistance block 20 -olf suitable conducting -Inaterial Asuch as a block of carbon or the like which is secured within the casing; 14 by means of brackets 21.-21 Fig. 2). A high .re-V

-sistance strip 22 of conducting material such as gold foil, tant-alum, 'platinum or other ma- -terial partiallyencircles the conductor block 420 and is connected at its ends to the diaphragm 18 The curved portion of the strip 22 lies immediatelyadjacent'the curved surface of the. block 20 and it will be understood that f any outward movement ofl the diaphragm 18fwillcause the strip 2.2v to be carried more intimatel into contact fwith 'the'` `adjacent curvedsur ace of the block." Like# wise, anyinwardmovement of the'diaphragm 18 will cause thestrip to becarried awayv from Acontact with the block. A screws24 which is threaded centrally of thelosedfend of the casing' '14 engageswith the medial point of the strip 22 'so as to hold the strip inontact at rent varying device wherein the high .tone point and in 'a iixedrelation with th ance element serves as thev diaphragm, and

block 20. `The screwg24also provides a -terl these terminals beingv connected with wire leads which pass through an opening 23 in the rear central portion of the housing 12.

-The terminal of one of the leads may be secured in position -by means of the screw 24 and the terminal of the other wire lead may be soldered to the diaphragm 18 or secured in any other suitable manner. i

From the foregoing it will be clear that u on the outward movement of the fdiap ragm 18 a certain portion ofthe high resistance strip 22 will be short circuited by being carried more into contact with the block 20 associated therewith and this short circuiti ing will eii'ectively vary the combined resistanceof the strip and the block and hence vary the amount of current flowing through the transmitter circuit. The amount of short circuiting or resistance variation eiected by the movement of the strip 22 'will be in accordance with and responsive to the vibrations experienced by the diaphragm 18 enter- 11. y Referring to Fig. 3 where an alternate form of the current varying device disclosed in Fig. 1 is shown, it will be observed that a cy.- lindrical casing 25 and aclamping ring 26 similar to the casing 14 and clamping ring 15 shown in Fig. 1, has a diaphragm 28 constructedof duralumin, aluminum or the like and elastic supporting rings 29 clamped therebetween. Extending transversely within the casing 25 are a palr of low resistance ing the mouthpiece vconductor blocks 31 which are separated at their medial point by an insulating member 32.A One l,of the surfaces of each ofl these blocks 31'is slightly tapered and disposed immediately-adjacent these tapered surfaces is a flexible high resistance strlp 33 of conductin material such as one of the non-corrosive no le' metals which is clamped at its extremities between the outer ends of the blocks 31 and the inner surface of the wall of the casing 25. .The extremities of the strip 33 are electrically connected with the Iterminals of wire leadswhichpass through openings 34 provided inthecasing 25 by means fsolder or in any other suitable manner. Interposed betweenthe medial portions of the strip 33 and the diaphra m 28 is a connecting member 36 and '1t wi l be apparent that this 'connecting member will serve to impart vibrations'from the-diaphragm 28 to the strip 33.

Thecurrent varying mechanism, just described, functions very similarly to the mech-v anism disclosedin connection withv Fig. 1.

' thestrip 33 will be effected andthe resistance As the high' resistance strip 33 is caused to move inwardly and thereb to be carried more intimately into contact w1th the tapered sur` face ofthe blocks 31. the short circuit-ing .of

of` the transmitter` circuit correspondingly lowered. This variation in the elective resistance of the strip 33 and the blocks 31 will cause a relative variation in the current flow and these changes will be'directly responsive to and in accordance with the vi V brations of the diaphragm 28. xThe structures disclosed in Fig. 4 are similar to those disclosed in Fig. 3, the only difference being that in Fig. 4 the diaphragm 28 and the co'nnecting member 36 are not present and the high resistance strip 33 has a double function, serving in contact with opposite sides of the strip 37 and is secured inthe wall of the casing 38 Y `and uponthe vibration'of the diaphragms 40 the members 42 willbe carried into more or less intimate contact with-the strip 37. The contaeting ofthe members 42 with the strip 37 will result in a resistance variation 'which will relatively affect the amount of current iow in the circuit and it will be noted-that in this instance, the high resistance strip is the' stationary element while the low members are movable.

The types ot current varying devices hereinbefore described may be made very compact and-by reasonof 'their compactness a transmitter. may be relatively small-'in size 'and convenient to handle. By reason of the fact that the movable parts are very light a transbot-h as a vibratory diaphragm and also as a positive current conducting element mitter ogE thel type disclosed will approach a condition of free, undamped vibration which is necessary or'high eiiciency and quality;

Although the invention has beende'scribed in connection with a certain type of telephoneI transmitter, it should be understood that the' current varying means may have many other applications and the invention is limited only bythe scope of the appended` claims.

What is claimed is: 1. In a transmitter,

a housing, a low resistance conductor block fixed within the housing and provided with an arcuate contact surface, a flexible hi h resistance conductor strip connected with t e diaphragm and secured'to the block medially of the arcuate surface, the strip being o erable in response to vibrations of the aphragm to vary its contact with thesurface of the block and thereby vary the eiective resistances of ythe elements.. l

2. In atr'ansmitter, a vibratory diaphragm, a fixed low resistance-element providedwith 'an arcuate vContact surface, a' support therefor, anda high resistance element of very 10W mass substantially enclosingthe arcuate surface of the low resistance element and having both of its ends vfastened to the diaphragm, the high resistance element being operable in response to vibrations of the dlaphragm to vary its Contact vwith the W resistance elesurface and operable in response to vibrations i ment to effect variations in their effective resistance. i

3. In a transmitter, a vibratory diaphragm, a stationary 10W resistance block having an arcuate contact surface, and a high resistance foil of very 10W mass partially encircling the low resistance block and having its ends fastened to the diaphragm, the foil being secured to the block medially of the arcuate of the diaphragm to vary the effective resistance 'of the block and the-foil;

In Witness whereof, I hereunto'subscribe ryname this 3rd day of September, A. D.`

HAL FREDERICK FRUTH.

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