US257686A - Electric telephone - Google Patents

Description

' UNITED STATES PATENT OFFICE.

JAMES I). FREEMAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE HOME TELEPHONE COMPANY, OFILLINOIS.

ELECTRIC TELEPHONE.

SPECIFICATION' for-lacing` part of Letters Patent No. 257,686, dated May 9, 18.52.

Application filed July 21, 1881. (No model.)

To all whom it may concern:

Be it known that I, JAMES P. FREEMAN, a citizen of the United States, residing at Chicago, in the county ot Cook and State of 111inois, have invented certain new and useful Improvements in Electric Telephones, and I do herebydeclare 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 appertans to make and use the same, reference being had tothe accompanying drawings, and to the letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to electric telephones adapted to the transmission ofarticulate speech by means of electrical waves or impulses traversing a circuit.

The object ot' my improvement is to obtain a greater permanency of adjustment of the electrodes.

`T0 this end itcousists mainlyin holding the electrode operated by the diaphragm in contact therewith by magnetic force, said electrode being attached to the keeper of a permanent magnet with which the keeper is in contact along one edge or line only, so that the keeper can oscillate on the magnet in unison with the vibrations of the diaphragm.

In order that my invention may be clearly understood, I have illustrated in the annexed drawings and will proceed to di scribe one form thereof which I have practically tested and found very eective.

Figure 1 is a front elevation of the door or side of a box to which my invention is shown as connected. Fig. 2 is a rear elevation of the same. Fig. 3 is an edge view. Fig. 4 is a transverse section on line :v .r ot' Fig. 2. Fig. 5 is a separate view ot' the permanent magnet and its keeper provided with the electrode to be operated by the diaphragm. 4

The same letters of reference indicate like parts in all the figures.

The door or side A,pret`erably made of hard rubber, is provided with the usual central fiaring depression and orifice, covered on the inside by the diaphragm B, which may be en-` circled around its periphery by a C-ring of soft rubber, andheld in place by a number of clamping spring-fingers, b b, healing on the rubber ring.

the permanent magnet C, which is in this instance an ordinary horseshoemagnet. The magnet is arranged to reach to about theeentral .line of diaphragm with its poles, it being at its neutral end secured to the dloor A by a clamp-bar, c, and a screw, c. A thin piece,c2, is placed between the door andthe magnet to separate it the proper distance from the diaphragm. The. keeper is preferably made flat, as shown, and the end of the electrode E eX- tending to and touching the center ot' the diaphragm is of such a length that it holds that portion ot' the keeper to which it is attached separated from the magnet, and onlyr permits the extreme edge ot' the keeper to remain in contact with the magnet, as clearly shown in Fig. 4. Thus the electrode E is held in contact with the diaphragm by the attraction of the magnet C exerted on the keeper D, which can oscillate on the magnet in unison with the vibrations of the diaphragm. The force. with which the electrode E is pressed against the diaphragm may be primarily regulated by proper adjustment ot' the magnet and keeper to make the instrument more or less sensitive. When once adjusted' no subsequent adjustments will be required. In order that the keeper may not slip on the magnet, I provide the latter with shoulders c3 c3, against which that edge of the keeper in Contact with the magnet abuts.

The xed electrodethe carbon button H- is carried in a cup, F', of a bridge or cross-bar, F, the ends of which rest on elastic cushions composed ot' rubber blocks I, and are secured by screw J passing through the rubber blocks into taps or nuts in the door A. In securing the cross-bar by the screws the rubber blocks are compressed, sothat they will force the crossbar back on looseningthe screws. The crossbar can thus be readily adjusted to bring the carbon button H into proper position with respect to the electrode E.

One pole of the batteryis connected by wire Ll to the cross-bar F, while the other pole thereof is preferably connected by the wire K to the diaphragm, though it may be connected by a wire, M, to the magnet C instead.

I do not claim broadly the a-pplication of a permanentmagnet for snpportin g byits keeper one electrode of a telephonie transmitter; but I believe myself tobe th'erst who so combined these parts that the electrode is held in contact with the diaphragm solely by the magnetic attraction exerted on the keeper by the magnet.

Having thus described myinvention, what I claim is 1. The combination, substantially as before set forth;s of' the diaphragm, the fixed perma nent magnet, the fiat oscillatory keepe'rin constant contact with said magnet, and the electrode carried by the keeper and held in contact with the diaphragm solely by magnetic attraction exerted on the flat side ofthe keeper.

2. The combination, substantially as before set forth, of the diaphragm, the fixed permanent magnet, the fiat oscillatory keeper in constant contact with said magnet, the elect-rode carried by the keeper and held in contact with the diaphragm solely by magnetic attraction exerted on the flat side of the keeper, and the fixed electrode.

3. The combination, substantially as before set forth, of the diaphragm, the electrode operated thereby, andthe oscillatory keeper, of a permanent magnet carrying said electrode, the fixed electrode, the cross bar supporting said fixed electrode, and the elastic cushions interposed between the cross-bar and the door or side to which the cross-bar is secured by screws.

In testimony whereof I affix my signature in presence of two witnesses.

JAMES P. FREEMAN.

Witnesses:

EDWARD C. WALLER, II. B. Pnoss'ER.

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