US1221167A - Automatic telephone-exchange system. - Google Patents

Description

C. L. GOODRUM. AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED SEPTIH, BIG- LQQLEEWYB 'Patented'Apr.3,1917.

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CHARLES L. GOODRUM, OF BROOKLYN, NEW YORK, ASSIGN OR TO WESTERN ELECTRIC COMPANY, INCORPORATED, 015 NEW YORK, N. Y., A CORPORATION OF NEW YORK.

AUTOMATIC TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Apr. 3, 1917.

To all whom it may concern.

Be it known that I, CHARLES L. GoonRUM, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Automatic Tele-' phone-Exchange Systems, of which the fol-v lowing is a full, clear, concise, and exact description.

This invention relates to automatic telephone exchange systems, and more particularly to circuit arrangements for controlling the operation of a switch which is set in accordance with directive impulses sent out by a calling subscriber.

The object of this invention is'to provide simple and eflicient means for controlling the operation of a. switch in response to impulses.

A feature of this invention is a line relay having a secomlary winding in inductive r lation to its primary winding. Current set up in such'secomlary winding controls a polarized relay to interrupt the circuit of a stepping magnet.

A further feature of the invention is an arrangement by which the ne relay remains energized during the sending of impulses to hold open the circuit of a release magnet.

The invention has been shown applied to a selector switch .ofthe well-known step-bystep type, and may obviously be used for controlling switc-"es of various types.

It is thought that the invention will be best understood from the following detailed description, reference being bad to the accompanying drawing.

in the drawingthe circuits of a selector switch are shown i full and at the. left is shown a subscrila-i"s substation apparatus.

\Vhen the subscriber at substation 1 desires to initiate a call, he removes his receiver from the hook, whereupon his line is extended by means of a; line tinder or other suitable device indicated by dotted lines at a and to the selector shown in the drawing. Linc relay 4. is then energized over a circuit from positive pole of battery, lefthand winding of relay l, conductor 5, sideswitch wiper (3 in its first position, line conductor 2, the substation apparatas of the calling subscriber, contact springs 7 of an impulse sending device 8, line conductor 3, side-switchwiper" U inrits first position, conduceor lO and right-hand winding of relay 4 to negative pole of batt ry. Relay 4 is energized and remains energized until the side switch moves into position 3, regardless of the operation of the sender 8, this circuit being maintained by a shunting resistance 11, which allows sufficient current to flow when contact springs 7 are separated to hold up relay 4.

When the circuit just traced was completed, an impulse was induced in a secondary winding of relay 4, this winding being 1n a clrcuit in series with a polarized relay 11, by means of conductors 12 and 12 This impulse, however, is of such polarity as not to cause the operation of relay 11.

The calling subscriber now operates the sender 8 to transmit a desired number of impulses. At the first break of the circuit through contact springs 7, an impulse of a polarity such as to cause the operation of relay l1 is'induced through the secondary winding of relay 4-. Relay l1 attracts its armature and closes a circuit for the primary stepping magnet 14, from grounded battery, winding of magnet 14 to groun at the armature and front contact of relay 11. When the contact springs 7 again close, an impulse is again induced in the secondary winding oi relay 4, but this time of such polarity as not to cause the operation of relay 11. It will thus be seen that by the use of a polarized relay, an impulse will be transmitted to the primary stepping magnet for each make-aml-break oi the circuit, whereas an ordinary relay, used in place of 90 a polarized relay. would send an impulse on each make and on each break of the line circuit.

When relay 11 first attracted its armature, it completed a circuit for slow release 95 escape magnet 15, from grounded battery, winding of magnet 15, side-switch wiper 16 in its first position, conductor-'17, armature and front contact of relay 11 to ground. The escape magnet is energized, and being slow to release, remains energized during the sending of the series of impulses.

After the series of impulses have been sent, the armature of relay 11 remains rc tracted for a comparatively long time and escape n'iagnet 15 is deiinergized, releasing the side-switch wipers controlled by it into their second position.

In the second position of the side switch, a circuit is closed for a secondary stepping magnet 18 from grounded battery, the wind,

ing of magnet 18, its armature and back a set of such terminals being indicated at 23,

24 and. 25.

Assuming now that an idle condition 'of trunks is indicated by ground on test terminals 25, and a busy conditionbythe absence of such ground, the secondary mag; net will continue to advance the brush set until test brush 22 encounters a terminal 25 'l \Vhen this takes having ground thereon. place, escape magnet 15 is energized over a circuit from grounded battery, winding of escape magnet 15, side-switch wiper 16 in its second position,brush 22 and terminal 25 to ground. The energization of the escape magnet releases the 'side-s\vitch wipers into their third position, the circuit of stepping magnet 18. The sub- ',scribers line has now been advanced to a 1 while-the side-switch wipers are in either positions, the dener-V 4 willresult in energi'zation of'a release magnet 26, its circuit succeeding switch, which may be a connector or another selector; c v

If the subscriber desires to abandon a call their first or second gization of line relay being from grounded battery, winding of magnet 26, off-normal contact 27, sideswitch wiper28 in either first or second position, and armature and back contact of relay'4 to ground. This release magnet 26,

on energization completes a locking circuit for itself through its armature and front contact, which maintains it energized until."

the switch is fully restored, at which time this'locking' circuit is broken by the operation of off-normal contact27.

After the side switch has moved its wipers into their third position, the release of the switch is controlled bythe succeeding switch. The restoration of the preceding switch will put a ground on terminal 25. A circuit is then completed for release magnet 2.6 from grounded battery, winding of magnet 26, off-normal contact 27, side-switch Wiper. 28 in its third position, brush .22 and said stepping relay,

.contact of said first rel and permanently opens 1n inductive pulses ;to said relay,

switch as previously described.

What is claimed is:

1. In a control circuit, a relay having .a

.primary winding and a secondary winding 1n inductive relation thereto, a polarized stepping relay in circuit with said secondary winding, a stepping magnetcontrolled by a release magnet, anda circuittherefor extending through a back ay. r I

In a telephone exchange system, an automatic switch, an impulse circuit therefor,

a polarized relay, a stepping magnet controlled thereby, a circuit for said relay, a reay arrangedmo inductively unite said circuits, a release magnet, and a circuit theresaid circuit extending through a front for, contact .of said last named relay.

3. In a telephone exchange system, an incoming. line, outgoing lines, an automatic switch for interconnecting said lines,-a relay having a primary windin in circuit with said incoming line and a secondary winding relation thereto, and an impulse sending device for transmitting immeans to control the operation of said, switch by'currents induced in said secondary winding by such impulses, said relay being maintained en'- ergized during the-sending of impulses.

4. In a telephone exchange system, an incoming line, switch for interconnecting said lines, controlling circuitstherefor, a controlling switch including a plurality of Wipers and contacts, an impulse sending device, having two windings in inductive outgoing lines, an automatic' a relay relation for controlling the setting of said automatic switch, and means including a back contact of said relay for preventing the release.of said automatic switch in certain positions of said controlling switch,

5. An automatic switch, an impulse circuit therefor, a circuit controlling the operation bf said switch, and means for inductively unitin said circuits, said means being arranged to prevent the release of said .switch in certain stages of its operation.

In witness whereof, I hereunto subscribe 1015 my name this 8th day of September A. D,, 1916.

CHARLES L. GOODRUM.

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