US428174A

US428174A - Telephone

Info

Publication number: US428174A
Authority: US
Publication date: 1890-05-20
Anticipated expiration: 1907-05-20

Description

(N-o Model.)

J. C. LUDWIG. TELEPHONE. No, 428,174- Patented May ZO, 1890.r

@lll 111-11-.-

UNITED STATES PATENT OFFICE.

JOHN C. LUDWIG, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF .ONE-HALF TO A. C. PAULSELL AND MARTIN CORCORAN, OF SAME PLACE, AND T. C. COOGAN AND H. T. COMPTON, OF OAKLAND, CALIFORNIA.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 428,174, dated May 20, 1890.

Application filed July 6, 1889. Serial No. 316,712. (No model.)

To @ZZ whom it may concern,.-

Be it known that I, JOHN C. LUDWIG, of the city and county of San Francisco, State of California, have invented an Improvement in Telephones; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relatesl to that class of telephones in which a diaphragm operates against 1o the armature of a magnet to induce a current over the line-wire; and my invention consists, essentially, in a hollow sounding frame or box, to which the mouth-piece is attached, the

.back of said frame or box forming the diaphragm, which acts upon the armature of the magnet.

My invention further consists in the combination, with a suitable diaphragm, of the particular' arrangement of armature and mag- 2o net hereinafter described; and my invention consists in the novel arrangement and combination of the hollow frame forming a sounding-box with a mouth -piece in its front, the back Wall serving as a diaphragm, the magz 5 net, the bobbins thereof, the armature of the magnet, and the arm of the armature resting against the back wall of the sounding-box, all as hereinafter fully described, and speciiically pointed out in the claim.

3o The object of my invention is to materially increase the efficiency of the telephone by increasing the loudness and distinctness of the sound transmitted. l

Referring to the accompanying drawings 3 5 for a more complete explanation of my invention, Figure l is a perspective view of my telephone, the casing A being vertically cut away to show the interior parts. Fig. 2 is a vertical section of my telephone.

A is the casing of the telephone. Y

B is the sounding-box or hollow frame, made of any suitable material-wood or thin sheet metal-as may be desired. This soundingbox or hollow frame is made with complete 4 5 front, back, sides, and ends, and into the front center of it is let the speaking-tube or mouthpiece C. The back wall b of the sounding box or frame forms the diaphragm of the telephone. Mounted on a cross-support D, back of the sounding-box, is the magnet E, having 5o the wire-Wound bobbins e.

F is the armature for the magnet, arranged on the face of the bobbins and supported by a suitable standard f, and'fromthis armature extends forwardly the arm G, the end of which rests in contact with the back wall or diaphragm b of the sounding box or frame.

I-I are the wires of the bobbins, one of which is the line-wire and the other the ground-wire, it not being intended in this telephone to use 6o any relay-battery at all. I have here shown these wires one to be connected with the post I and the other to be connected with the post J.

The sounding-box B is held in place within the casing Ain any suitable manner, as by the blocks K.

The sounding or speaking box or frame B,

I have found by experiment serves as an airchamber, in which the sound of the voice is materially increased and acts through its 7o back wall or diaphragm b with increased power-so much so that a relay or battery of any kind is entirely unnecessary, the current sent over the line wire being sufficiently strong to operate on the telephone at the other 7 5 end with great power and distinctness and emitting a loudness of sound, much to be desired. The back b of the box B, acting as a diaphragm, is an extensive one, and is very sensitive, and acting against the arm G of 8o the armature F produces vibrations, which serve the general purpose of efficiency, for which the instrument is intended.

I am of course aware that sounding-'boxes for increasing the volume of sound arenot new; and I am aware that in mechanical telephones such chambers or boxes have been used-as, for example, the' old and common form of mechanical telephone, consisting of two tin cans and an intervening string; but 9o my invention does not lie in merely a sounding-box, but in the combination of such in a magnetic telephone, whereby a better result is produced and the usually necessary relay or battery is entirely dispensed with.

Having thus described my invention, whatI claim as new, and desire to secure by Letters Patent, is-

In :L telephone, the Combination of the holwhieh forms the diaphragm, substantially :1s 1o low frmne forming; :L sounding-hex, the spenkherein described. ing-tube or mout-h-peee connected centrally In witness whereof I have hereunto set; my with the front ol' said frame, the nmgnet at hand. Y 5 the beek of the frame, the hohbin'S-of the JOHN C IUDXVN,

nmguet, the arnmture of said magnet on the L face of the bobhins, :md the projecting :mn Titnessesz of them'nmtnre, the end of which restsng'ninst II. NOURSE, andin Contact with the hoek. wall of the frmne 1I. C. LEN.