US1367705A - Automatic telephone system - Google Patents

Description

C. W. KECKLEB. AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED MAR.2I, |91?.

Patented Feb. 8, 1921.

HMM/2 ffy 'v4/flu UNITED STATES PATENT OFFICE.

CHARLES W. lKEGKLER, OF NEWARK, NEVI JERSEY, ASSGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORIPORATION 0F NEW YORK.

AUTOMATIC TELEHONE SYSTEM.

Specification of Letters Patent.

Patented Feb. 8, 1921.

Application filed March 21, 1917. Serial No. 156,314.

Y 10 all 'w hom t may concern Be it known that I, Ci-mnnns W. Klienten, a citizen ot the United States, residing at Newark in the county ot Essex and State of New Jersey, have invented certain new and useful Improvements in Automatic Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to substation circuits for use with substation sending devices tor automatic telephone exchange systems.

Heretofore in automatic telephone systems ,in which the calling subscriber operates a calling device or impulse sending mechanism to control the operation ot selecting apparatus, it has been necessary that the subscriber remove his receiverfrom the switchhoolr before operating his calling device, so as to allow a line finder or an equivalent switch to operate at the central office to extend the line circuit to the selecting apparatus which is to be controlled by the first series of impulses.

The object of this invention is the provision ci a substation circuit arrangement for use with a calling device whereby the line circuit is closed to start the line finder or an equivalent switch at the central cnice as soon as the calling device is moved from its normal position. An oit-normal contact is closed by the initial movement of the dial of the calling device which completes a bridge across the line conductors and allows the line' finder to operate before the impulses are transmitted by the return movement of dial to its normal position.

This invention may be more readily understood by referenceto the accompanying drawings, in which Figure l shows a preferred substation arrangement embodying this invention; and Fig. 2 shows a modication of the circuit arrangement shown in Fig. l.

Beferring'to Fig. 1 of the drawings, 1 designates the usual ringer in series with a condenser 2 in the normal circuit of the line conductors 3 and 4. A telephone transmitter 5 and a primary winding 7 of an induction coil 6 are included in a normally open bridge of the line conductors, and are arranged to be brought intocircuit upon the removal of the telephone receiver 9 from its switchhook 10. The receiver 9 and the secondary coil 8 of the induction coil 6 are also arranged to be brought into circuit upon the removal. of the receiver.

Associated with the substation circuit is a calling device 11 having a dial 12 rotatable about the axis 13 and provided with the teeth A hcllcrank lever 15, pivoted at 1G is located in operative relation to the dial 12. One arm of the lever is engaged by the teeth oi the dial 12, and the other arm is eiigaged by the contact arm 17, which also engages the contact 18. The contact arm il? is connected to contact 24 by a conductor 26. Two conductors, 19 and 20, eX- tend from the induction coil leads, as shown, and terminate in the contact 21 and the contact arm respectively.` An arm 23 is fastened to the wheel. 12 and is removable therewith. Contacts 24., 21 and contact arm 22 constitute an off-normal switch, and the closing of this switch when the calling device moves from normal places a bridge across the line conductors 3 and 4l, and also places a shunt around lthe receiver 9, which shunt is maintained until after the required number of impulses is sent and the calling device returns to normal. y

rThe operation is as follows, it being assumed that the calling party does not move his receiver until after he has started operating his calling device to send out the lirst set of impulses. Only so much of .1 telephone system has been shown as is thought necessary for a complete understanding of thc invention. The system hercin disclosed is similar to that shown in Patent No. 1,231,013, issued June 26, 1917, to C. L. Goodrum. As a preliminary to Vthe sending of the impulses, the dial 12 is moved in the direction of the arrow a required di,.- tance corresponding to the number ot impulses to be sent, after which it is returned to normal by the action of a spring (not shown). As soon as the dial leaves its normal position, a circuit is closed :tor the start magnet 30 of the line finder from grounded battery, right-hand winding of relay 30, line conductor at, conductor 27, contact 18, contact arm 17, conductor 26, contact 24:, conductor 19, primary coil 7, line conductor 3, lett-hand winding of relay 30 to ground. Relay 30 becomes energized and starts the line switch operating to extend the line conductors 3 and 4 to a first selector. As soon as the calling line is found cut-off relay 111 is energized and opens the circuit of relay 30.

In the return of the dial l2 to its normal position, the teeth la engage the bell-crank lever l5, thereby making and breaking, at contacts 17 and 18, the bridge across the line circuit which by this time extends to the `first selector and completes a circuit for a line relay Ll0 oi this selector. rlhe relay 40 is thereby energized and denergized a number or times Acorresponding to the number of impulses transmitted, to move the selector to the desired group or' trunks. rlhe relay E30 will be denergized at this time, because as soon as the line finder linds theV calling line the cut-ofi relay fl-.l is energized to open the circuit of relay 30.

The moving of the dial from normal also places a short circuit, conductor 19, contacts 2l` and 22 and conduct-or 20, about the receiver. rThe switch contact 2Q is arranged to Vengage contact 2l before the circuit through contact 24 is completed. lWhen this circuit is completed through the primary coil 7 to start the line finder, and later made and broken to transmit impulses to the selector switch, the current which is induced in the secondary by these current changes does not-affect the receiver' because of the shunt around it. Therefore, when the sub scriber removes his receiver during the operation ot the calling device, he does not receive adisagreeable click in his receiver each time a circuit change is produced.

Upon the dialreaching its normal posi-V tion, arm engages contact arm 22, thereby Aopening the shunt for the circuit of receiver Y), but there is no effect produced in the receiver, since at this time there is a steady flow of current through the primary coil :trom ground at the selector, conductor 3,

contact arm l0, transmitter contact arm the primary coil i oit the induction coil asv in Fig. l, as the calling device in this circuit arrangement short-circults all oi. the substation apparatus as soon as it leaves its `normal position. The disadvantage et this circuit arrangement shown in Fig. 2 is that the calling subscriber receives-a click in his receiver at the end of each dial movement, when current is restablished through the primary of the induction coil.

V'Jhat is claimed is: 4

l. ln a substation circuit for an automatic telephone system, a calling device having normally closed impulse springs, a normally open line circuit, a hook switch, a normally pen short-circuit around the hook switch,

and means operated by the initial movement oi' said calling device for closing said short-circuit and closingsaid line circuit through said impulse springs.

ln a substation circuit for an automatic exchange system, a calling device having' impulse springs, sets of ofhnormal springs controlled by said calling device, a line circuit includingA said impulse springs and one set of said off-normal springs, and a short circuit around the telephone receiver controlled by another set of said oli-normal springs.

3. ln a substation circuit for automatic telephone systems, a calling device having normally closed impulse springs, a normally open line circuit, a receiver, a normally open short circuit around said receiver, and means operated by the initial movement of said calling device for first closing said short circuit and then closing said line circuit through said impulse springs.`

a. ln a substation circuit for automatic telephone systems, a calling device having impulse springs and sets of onormal springs, a line circuit including said impulse springs and one set of otfnormal springs, a telephone receiver, and a short circuit around said receiver including another set ot ofi-normal springs.

ln a substation circuit for automatic telephone systems, a calling device having impulse, springs and sets or oli-normal springs, a line circuit including said impulse springs and one set of off-normal springs, a telephone receiver, a short circuit around said receiver including another set of off-normal springs, and means controlled by the movement of the calling device for closing the short` circuit in advance of closing the line circuit.

In Witness whereof, l hereunto subscribe' my naine this 20th day of March A. D., 1917.

' CHARLES KECKLER.l

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