US295806A - Chaeles a - Google Patents

Description

(No Model) l C. A. RANDALL.

. l TTLEPHUNIC TRANSMITTER.

No. 295,806. TatenteaT/m. 25. 1884.

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'i lNiTED STATES "PATENT OYEEIGE,

.cEAELEs A. RANDALL, oE NEW vonk, N. Y.

TELEPHONIC TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 295,806, dated March 25, 1884.

Application led May 3, 1883. (No model.)`

.To all whom, it may concern."

Be it known that I, CHARLES A. RANDALL, a citizen of the United States, residing at New York, in the county and State of New York, have invented new and useful Improvements in Telephonie Transmitters, of which the following is a specification.

This invention relates to that class of telephonictransmitters in Which the movements of a vibrator under the inliueuce` of soundwaves are communicated to the current-varying electrodes through an amplifying-lever. This type of -transmitter is illustrated in PatentsNos.` 235,019, 235, 020,238,434, and 255, 333, heretofore granted to me, and is designed to secure a greater range of variation of contactpressurc between the electrodes than is possible vbetween electrodes acted upon by thedirect movement of a diaphragm or vibrator.

The objects of my presentimprovem ent are, first, to obviate the necessity for adjusting the electrodes under variations of temperature or other conditions; second, to dispense `with spring-supports for electrodes, such supports being liable to variations of tension, which `interfere with the proper action of the electrodes and render frequent adjustments necessary; third, to remedy the abrupt and irregular breaking and varying of the electric current by the'jostling unsteady movements of electrodes mounted on independent supports under the iniiuence of loud or abrupt sounds; fourth,to reduce thewear between the currentvarying electrodes; fifth, to obviate injury to the electrodes by electric sparks; sixth, to prevent the` electrodes from being disarranged by expansion and contraction of the diaphragm or other vibrator, which gives motion to the amplifying-lever.

With these objects in view my invention consists in a new mode of supporting the electrodes in their proper relative positions, and in certain novel combinations of devices,which will be readily understood from the following particular description, in connection with the accompanying drawings, in which-- Figure I is a rearperspective view of a transmitter constructed according to my invention. Fig. 2 is an enlarged longitudinal section of one ofthe long arms of the amplifying-lever and diametric section of the movable contactpieces carried thereby. Fig. 3 is a side View of an instrument in which the vibrator is moved by the variations of attraction in the core of an electro-ma net. Referring toFig. l, the letter D designates a diaphragm which may be supported in the usual manner, and provided with a mouthpiece, which is not shown in this figure, from the fact that it is a rear view. v

The letter S indicates a metallic rock-shaft mounted in bearings s s, and having an upwardly-projecting short arm, L, which is connected with the center of the diaphragm by a link-rod, R. Three long arms, L L'L L3, de- 65 pendfrom the shaft S, and two, `L2 and L3, are insulated from the shaft and the other long arm and the short arm. These long arms, the short arm, and part of the shaft compose, es-

sentially, a mechanical lever having one short 7o and three long arms, and thevibrations of the diaphragm will be amplified by all the long arms, in accordance with the proportion v between their length and the length of the short arm. Vhen it is desired to use only one of these block-supporting arms, arm L would preferably be selected, as its extension or short arm is the means by which the vibrator controls the contacts. Each of the long arms has mounted loosely upon it, in the present instan ce, two cylindrical blocks of carbon, C C, perforated centrally for the passage ofthe rod, and held in place upon said rod by a suitable shoulder or abutment, against which the bottom block rests. In one instance an adjustable nut, N, screwed upon the rodtis used. In another instance a pin, P, which may be passed through any one of a series of holes in the rod; and in still another instance a rubber washer, W, lwhich hugs the rod, but may slide thereon. In all three instances the blocks are adjustable, in order that they may be brought to the most effective position on the rod. Of course, one block C on each rod would vary the contact, and hence the circuit; 9 5

but I have shown two, as preferable in givin a greater degree of variation. The two blocks C G of each rod are connected by a iine wire, f, i and one of the blocks-no matter whichuponeach rod, is connected to `a leading-oftwire, these wires being respectively desig= nated by the lettersY, Y', and Y2. The arms L', L2, and Ii3 are respectively connected to binding-posts B, B', and B2 by Wires y, g/ ,and y?,

and these binding-posts are connected to separate batteries G G G2, having' opposite con` nection to ground or otherwise. rIhe wires Y, Y', and Y2 are connected to binding-posts 133,]3, and B5, and are each supposed tohave nal 1o ground-connections, but may be intermediately connected in line-circuits including receivinginstruments, or to primary circuits of induction-coils, the secondary coils of which are connected in main lines. The said Wires may be connected to independent line-circuits, or

they may all be connected to the same main line, or all to one induction-coil primary. When they are connected to one circuit, the

currents of all the batteries will of course be 2o combined upon such circuit. Imore especially contemplate their union with one line, so that all the currents of all the batteries, as varied by all the contacts, shall be jointly in one circuit, obtaining thus a larger quantity of current with the electro-motive force of one of the sections of battery. In addition, while the danger of non-adj ustment or lack of proper relation between the electrodes for effective work is reduced to a minimum, if such danger should become a reality in one set of electrodes, the' instrument Wound remain operative, because of the remaining sets.

The perforations of the blocks C C are of a size, as clearly shown in Fig. 2, to permit some considerable play of the contact-blocks upon their supporting-arms, the vibration of an arm causing a corresponding play or sliding of its contact-blocks within their range of motion.

'Ihe operation is as follows: rIhe arms are Aro given normally such an inclination `that the interior walls of the perforations through the blocks will rest upon and contact with the supporting-arms. Vhenthe diaphragmisvibrated by the impingement of sound-waves upon it,

its movement is transferred to the short arm of the lever system, thence to the long arm, at whose extremity it is largely amplified. The movement or vibration there is sufficient to jostle or move the blocks, or to cause them to 5o have a slight play around the supporting-rod sufficient to vary the contact between them, and so vary and control the current in the circuit. The amount and rapidity of these variations will of course depend upon the rapidity and amplitude of the vibrations or.

. except that the vibrator D is the armature of an electro-magnet, as shown at M. This magnet may be connected in one main line, and

the instrument serve as a repeater to transmit the message over one or more other lines connected with it, as already described, or may be used as a relay.

In my transmitter as now described, it will be seen that there are no nice adjustments requiring attention. In fact,` after the contactblocks are first given a proper position on their supporting-arm the instrument never requires any further adj ustment; also, there are no electrode-supporting springs, which would by their changes of tension render frequent adjustment necessary. It will also be noted that the contact-blocks are in such position to each other and their supporting-arm that they cannot easily be irregularly thrown or vibrated out of operative position by abrupt, loud, or violent sounds at the transmitter. Another advantage is that as the electrodes have comparatively large contact-surfaces the wear in use is much less than when two small points only are in contact, as is the usual method. It should also be noticed that, owing to the large contact-surfaces of the electrodes, larger batteries can be used than heretofore without injury to the electrodes by sparks at the breaking yof contact. Finally, it will be observed that as one electrode is carried by the other there will be no disarrangement of their proper relative positions by eX- pansion and contraction of the diaphragm or motive vibrator. y

Having now described my invention and eX- plained the operation thereof, I wish it to be understood that I do not confine myself to any of the particular constructions or arrangements shown in my drawings, but may vary any or all of them in any manner for the elflcient carrying out of my invention without departing from the essential principles thereof.

Vhat I claim isl. In a telephonie transmitter, the combination of an amplifying vibratory lever forming one electrode, and the opposite electrode mounted loosely thereon and supported thereby, so that the contact of the two electrodes may be varied, substantially as described.

2. In a telephonie transmitter, the combination of a diaphragm or vibrator, an amplifying-lever operated thereby and forming an electrode, and an opposite or second electrode loosely mounted upon the long arm of the lever, the two electrodes being arranged and adapted to -vary contact Vupon movement or vibration ofthe lever, substantially as described.

3. rIhe combination of a lever forming one electrode, a secondfelectrode loosely mounted thereon and carried thereby, and means, substantially as described, for adjusting or regulating the position ofthe second electrode upon the first, as set forth.

4. The combination,with the diaphragm and short lever-arm connected therewith, of a plurality of long lever-arms provided with electric contact-surfaces and connections, substan- IIO i by, each lever -forming one electrode loosely carrying and supporting a second electrode, a series of batteries-one for each lever and connected thereto--and connections to the line or lines from the second electrodes, substantially as described.

In testimony whereof Ihave hereunto set my hand in the presence of two subscribing Witnesses. y

C. A. RANDALL.`

Vitnesses:

J. W. HUGHES,

W. J, CAHooNE.

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