US275310A - Edwaed l - Google Patents

Description

(No Model.)

B. L. WILSON.

TELEPHONE TRANSMITTER.

Patehted Apr. 3, 1883.

Inn/e Yoko 7?- UNITED STATES PATENT OFFICE.

EDVARD L. W'ILSON, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE AMERHJAN BELL TELEPHONE COMPANY, OF SAME PLACE.

TELEPHONE-TRANSM ITTER.

SPECIFICATION forming part of Letters Patent No. 275,310, dated April 3, 1883.

Application filed January 27, 1883. (No model.)

I 0 all whom it may concern:

Be it known that I, EDWARD L. WILSON, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain Improvements in Telephone-Transmitters, of which the following is a specification.

My invention is an improvement in micro phonic or contact telephones-such as are in common use as transmittersand its objects, broadly stated, are to provide an improved method of supporting the diaphragm in place to minimize the cost, to simplify construction, and to dispense with parts which, while useful, by reason of their fragility and uncertainty of operation, are liable to cause annoyance both in construction and exploitation. In such transmittingtclephones it is well known that the current of a voltaic battery passing through two contact electrodes is varied. The vibrations of the diaphragm, developed by the action of the voice, thus act directly upon the contact-electrodes, varying their pressure upon one another, as a penultimate consequence producing variations in the resistance of the circuit, and as an ultimate consequence producing variations of strength in the current flowing in the circuit. Experience has demonstrated that all transmitting-diapbragms have distinct initial vibrations of their own, and when vibrations are produced in them from any external cause-for example, by vocal utterances in near proximity to them-it is difficult, and sometimes impossible, to obtain distinctness in the speech reproduced by the receiving-telephone unless the initial vibrations are first dampened or subdued. It has been customary to deaden these unnecessary and pernicious vibrations by clamping one edge of the diaphragm firmly to its seat by a metal clip, and by causing the other edge to be elastically held by a thin steel spring fastened at one end to thet'rame of the diaphragmseat, and pressing with its free end, which is covered with a pad of some textile or elastic non-conduct0r-such as rubber or clothupon the inner face of the diaphragm. This device. is used ordinarily in the well-known Blake transmitter, and is usually called a damping-spring. In practice these damping-springs have been productive of much trouble and annoyance in the course of manufacture and process of testing the transmitters, as well as during the operative life-time of the same. It has been found difficult to procure steel of the exact texture and temper required, and when such springs are procured they are frequently broken during the process of adjustment. which is a work of great delicacy. Moreover, when at work it is more or less diffioult to maintain a proper adjustment. By my invention 1 am enabled to dispense with the damping-spring, and may, if desired, dispense also with other delicate parts, as will be hereinalter succinctly described.

My invention consists chiefly in providing a magnetic support or seat for the diaphragm, and in combining the same with the other parts of the instrument in such a manner that no other means of holding or damping the diaphragm are necessary.

In the drawings, which form a part of this specification, for greater perspicuity I show the working parts of an ordinary Blake transmitter in contrast with a similar instrument furnished with my improvement.

Figure l is an elevation of the working parts of a Blake transmitter seen fromthe rear. Fig. 2 is a sectional side elevation of the working parts of the same on the line 00 00, Fig. 1. Fig. 3 is a vertical section, showing my improvement. Fig. 4 is a sectional elevation on the lineyyot' Fig. 3, looking from theinside. Fig. 5 is a rear elevation, and Fig. 6 a section on the line 2 z, of another form of microphonic transmitter, also furnished with my improvewent.

I will first briefly describe the Blake transmitter, which is depicted in Figs. 1 and 2.

A vibrative diaphragm, D, fringed with a rubber pad, (I, which overlaps both edges, is supported in a ring-seat formed in a metal frame, A, which also has at top and bottom a projecting piece or lug, S S From the upper lug, S, by means of a flat spring, a, an adjusting-lever, B, is suspended, which carries on an arm extending inward from its upper extremity the two contact-electrodes ot' the circuit 0 and O, the former beinga small piece of platinum and the latter a button ot'earbon in a casing of metal. The platinum electrode is suspended from the arm of the lever by a light spring, 0, while the carbon is similarly suspended by a heavier spring, b, Which is in electrical contact with the adjusting-lever, the spring 0' being insulated therefrom, so that the only electrical contact between the two springs is made through the platinum and carbon electrodes. An adjusting-screw, R, passes through the lower lug, S and bears against the angular extremity of the lever B, andis screwed up until the platinum electrode is broughtinto contact with the diaphragm, and when so placed any vibration of the diaphragm is participated in by the electrode. A metal clamp,f, screwed to the iron frame presses tightly on the padded rim of the diaphragm, and a damping-spring, g, on the opposite side, is similarly secured, and by its free end, which is padded, presses on the diaphragm near its center and averts or obviates any noxious or unnecessary or unwarranted vibration.

In my improvement I replace the metal frame constituting the ring-seat by a pair of semicircular bar-magnets, M M, having like poles in juxtaposition, as shown in Fig. 4, wherein N N represent the two north and S S the two south poles. These magnets are held together and in place by brass brackets or standards 6, which are screwed thereto at top and bottom, and which may also be screwed to the front board of the transmitter-box. The holes a are for the latter purpose. From the upper bracket extends the lug E and from the lower bracket the complementary lug E, which both subserve the same purpose, as in the ordinary Blake transmitter. The dampingspring 9 and metal clamp fare both entirely dispensed with, since it is tound that by forming the diaphragm-seat of magnetic material the diaphragm is both efficiently supported and controlled.

In Figs. 5 and 6 I show another form of contact-telephone to which my invention is applied. In this form also the diaphragm is held by magnetism alone, and the platinum electrode, with its delicate suspending-spring, is superseded by a condnoting-electrode, G, rigidly secured tothediapragm D. This islightly pressed upon by the usual spring-suspended carbon button, 0, and the initial pressure is given by combining an auxiliary spring,j, riveted at its upper end to the suspending-spring of the button, with a metal bar, F, fastened at its end thereof to the abutment or lug E, and provided at its lower and free end with an adjusting-screw, k, passing through the said bar and against the free end of the auxiliary spring. By means of this device a delicate but firm initial pressure may be obtained between the electrodes.

The electrode U is brought into the voltaic circuit by fastening one of the wires thcreot'to the diaphragm, as shown in Fig. 5. In this form of instrumentthcre is a small bent piece, It, fastened to the lower bracket, 0, for attaching the transmitter to the front board of the transmitter-box.

Although I have shown the magnets forming the frame or seat of the diaphragm as being semicircular, I may, without departing from the spirit of my invention, form the same of a complete or closed circular magnet; or I may use four quandrantal magnets, it being evident that in this case form is not of paramount importance. I may also, if I so elect, place opposite instead of like poles in juxtaposition.

I claim- 1. In a battery-telephone, the combination, with the diaphragm, of a permanently-magnetic frame or support adapted by the force of the magnetism to hold the edges of said diaphragm, substantially as described.

2. In a battery or variable-resistance telephone, the combination, with the diaphragm, of a magnetic frame orsupport, the magnetism of said frame or support being independent of the current upon the line, substantially as described.

3. The combination of the diaphram, magnetic frame therefor and contact-pieces or electrodes, substantially as described.

at. In a telephone, the combination, with the diaphragm, of a frame or support comprising one or more permanent magnets, substantially as described.

5. In a telephone, the combination, with the vibratory diaphragm, of a seat or support therefor comprising curved or semicircular magnets, so disposed as to attract and hold the diaphragm at its edges only, substantially as described.

(5. A telephone-transit]itter consisting of a vibrating diaphragm, a circular or double semicircular magnetic frame therefor, brackets of non-magnetic metal attached thereto-one on each side-and forming a partial ring-seat for the diaphragm, combined with the circuitelectrodes composing the variable resistance, and devices for adjusting the initial pressure of the same, substantially as hereinbefore described.

7. The combination, substantially as hereinbefore described, ot' a vibrating diaphragm adapted to control the electrodes of a variableresistance transmitter, with two semicircular magnets placed with like poles in juxtaposition, and two non-magneticyoke-pieces therefor, uniting the said magnets and forming thereon a seat or support for the said diaphragm, in which it is magnetically held.

8. The combination, substantially as described hereinbefore, ofa vibrating diaphragm, a frame composed of two semicircular magnets held together bynon-magnetic yokes, the said yokes extending inwardly and forming, with the magnetic frame, a holder or seat for the diaphragm, whereby the said diaphragm is freed during its operation from hurtful vibrations, independently of the employment of a damping-spring.

Intestimony whereofI have signed my name to this specification, in the presence of two subscribing witnesses, this 25th day of January, 1883.

EDWD. L. WVILSON.

Witnesses:

J. H. OHEEVER, GEO. WILLIs PIERCE.

Images