US1055870A - Telephony and telegraphy. - Google Patents

Description

S. G. BROWN.

TELEPHONY AND TELEGRAPHY.

APPLICATION FILED DEO.12,1910.

Patentbd Mar. 11, 1913.

UNITED STATES PATENT OFFICE.

, SIDNEY GEo'EoE BROWN, 0E LONDON, ENGLAND.

TELE HONY AND TELEGRAPHY.

Specification of Letters Iatent.

Patented Mar. 11, 1913.

Application filed December 12, 1910. Serial No. 596,904.

- contacts or electrodes of which the resistance between them is controlled by local means; the object being to render the sound character and to render possible of employment minute or imperfect sounds or signals so that the same may be magnified, transmitted and received or recorded with more expedition accuracy and clearness than by the methods ordinarily employed.

According to this invention the resistance included at the point of contact of the electrodes is regulated by a local electromagnet the core of which is provided with a sheathing of copper or other metal, said sheath ing serving, by reason of the eddy currents set up therein, to'maintain the action of the electromagnet constant by excluding from the winding thereof the ill effects of the rapidly varying currents which traverse the contacts. The same effect may also be obtained by shunting the electromagnet with a suitable resistance or capacity.

The variable resistance contact device may comprise contacts or electrodes composed of carbon, metal or of carbon alone or of osmium-iridium and mounted in adjustable relation to each other. To this end they are respectively mounted on an adjustable arm, and a reed, tongue or strip which may be formed of hardened tempered steel;

the latter being influenced by the line and by the aforesaid local electromagnet. By utilizing a reed, tongue or strip for carrying the contact or conductor, outside disturbance may be avoided. The vibrating member is adapted for adjustment by means of a curved or knife edge bearing.

.In order that the said invention may be clearly understood and readily carried into effect I will proceed to describe the same 'with reference to the accompanying draw ing, in which Figure 1 is a side view of aninstrument embodying the present invention showing the casing in section and the cover in the open position. Figs. 2 to 4 are diagrammatic views of the electrical connections for the said instrument.

The aforesaid contacts or electrodes which may be pointed as regards the one and flat as regards the other, or be composed of powdered or'finely granulated material,

such as carbon, metal, or osmium-iridium,

are indicated at a a, the former of which is carried by a hinged or pivoted arm a and the latter a by a reed, tongue or strip 0, of hardened tempered steel or other suitable material capable of being vibrated under the influence of an electromagnet 1) arranged in the line and of a local electromagnet 1) arranged in the circuit of the local battery or source of current 0'; these electromagnets being shown as superimposed. The arm a which carries the contact a is hinged or pivoted at a to the framing a of the instrument in such a manner as to permit of the arm being turned into the position shown in broken lines when required to admit of cleaning or otherwise operatin upon or inspecting the contacts a a. he arm a is arranged so that its free end a rests upon or against a screwed stud or similar devices b whereby the position of the contact a thereon may be adjusted relatively to the contactva" carried by the reed or strip a. This latter may be secured to the framework a of the device also with a capability of adjustment and with this object in view the extremity (1 thereof remote from the contact-o is attached to the aforesaid framing by means of suitable studs, screws or the like b, b the necessary adjustment of the reed a may be readily effected by mounting the same upon a bearing surface 1) b ef curved or knife form so that a tilt may be given to the reed in the one or the other direction. By thus mounting the vibrating contact a on a reed tongue or strip a such as herein referred to the harmful effects due to outside disturbances experienced when the contact is mounted on a diaphragm or disk are avoided and improved working is obtained.

The windings 'c c of the electro-magnets b b -are mounted upon a core 0' and the winding 0' of the e'lectro-magnet b which carries the line currents to be magnified and the winding 0 of the local elect-ro-magnet both act upon the reed, tongue or strip a pertaining to the contact or electrode (1' when the arrangement is in operation. The core 0 of the local electro-magnet is provided with a sheathing or lagging 0 of copper or other metal, in the form of a tube or a winding which serves to maintain the action of said electromagnet constant ,If

a winding f (Fig. 4) be used the ends maybe brought out to terminals f f and the circuit completed by. placing a resistance ff an inductance f or a capacity f across the same. The instrument is arranged within a casing e which is provided with a hinged cover 6' so as topermit of the arm a being turned out of the Way to allow the contacts a a to be inspected or cleaned.

The local or magnifying circuit contains a battery or other source of current 0 the cont-acts a a, the windings c of the local electroniagnet b the primary 0 of a transformer a pertaining to the receiver or transmitter and theusual galvanometer or other instrument 0 whereby the required indication may be obtained such as that of the current that flows through the contacts, thereby indicating the resistance between the same. Owing to the increased resist ance ottered by carbon, itis necessary, tosuccessful working to increase the resistance of the. local circuit over that which would be necessary if metal contacts were used; the latter as is well known being of higher electrical conductivity. The winding .0 of'the localeleetromagnet b may be-shunted by a re-' sistance d or by a suitable capacity Fig. 4; the bulk of the local current however passes through the winding of the magnet. \Vhen the core 0 of the local electromagnet is lagged or covered with a copper sheathing 0 (Figs. 1 and 2); the shunt resistance 1] or capacity may be dispensed with. The

improved arrangements permit of stronger currents being employed in the local circuit and the magnification of the signals, or sound waves will be increased owing th the greater energy available in this circuit.

'hat I claim and desire to secure by Let-- ters latent of the United States is:

I. In an apparatus for the electrical transmission and reception of signals, the combination in a, microphonic resistance varying device, of a hinged member, an electrode mounted on said member, a vibratory member, a knife bearing forsaid vibratory member, means for adjusting. said member on the knife bearing, an electrode on said vibratory member acting in. conjunction with the previously mentioned electrode, an electro-magnet for controllingthe resistance be tween the coacting electrodes, and means for preventing the ill effects of the "arying currents which traverse the electrodes from entering the winding of the said electromagnet. I

2. In apparatus for. the electrical trans mission and reception of signals, the combi nation in a microphonic resistance'varying device, of a hinged member-, a'carbon electrode mounted on said 'member a vibratory member, a carbon electrode thereon acting in conjunction with the previously mentioned electrode, a knife bearin for said vibratory member, screws for adjusting the vibratory member onthe knifebearing, an electro-magnet for controlling the resistance between the coacting electrodes, and a copper lagging on the. core of said electromagnet for preventingt-he ill effects of the varying currents which traverse the electrodes from entering the winding of said magnet. I

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

SIDNEY GEORGE BROIVN. \Vitnesses B. Smwure Sntirn, G. ll. \VARREN.

Images