US1669031A - Rotary line switch - Google Patents

Description

May s. 1928.

B. D. WILLIS ROTARY LINE SWITCH Patented May 8, 1928.

' NI E ST AUTOMATIC 'nnno'rmo INQ, or CHICAGO, ILLINOISQA conrona'rion or DELA- WAR Application filed May 9,

This inventionrelates in general to automatic switches, but is concerned more particularly with switches of the automatic hunting type, commonly known as .line switches. Switches of this character are used in automatic telephone systems, individual to each subscribers line, and; when used in this situation the. function of each line switch is to select'a trunk to an idle succeeding switch, for example, a first se lector, and connect the subscribers line thereto.

The object of this invention is to provide new line switches of the rotary type having ahome or normal position inwhich theswitch wipers normally rest. WVhen a call is initiated, the wipers are rotated in a forward direction in-search of a trunk to an idle succeeding switch, and come to rest when they engage the contacts at which the conductorsot a trunk to an idle succeeding switch terminate. WVhen the call is over withand the switches associated with. the talking connection are released, the wipers of the line switch are again automatically rotated in the forward direction until they reach the homeposition. y

The utility and advantages of the homeposition type rotary line switch are commonly known to those familiar in the art, so no discussion of these subjects is given.

The new line switches which form the subject-matter of this invention are illustrated by means ofthe-usual schematic cirouit diagrams in Figs. 1 .and 2 of the accompanying drawing. Refer-ring to'this draw" ing, in Fig. 1 is shown a subscribers tele phone substation A with a line terminating at a central automatic exchange in the individual line switch LS, which is of the home position rotary type. At the banks of the line switch access is had to first selector switches. These selector switches may be of any well known type, the vertical and rotary, for example, and are responsive. to the first digit dialled by the calling sub- SCl'lbGlC. One of these selector switches is indicated in Fig. 1 by reference letter S, only those elements having to do with the operation of the line switch being shownj A call from the substation A to another subscriber may be extended through line switch LS, selector S, and through other selectors, d ma-sing n th size at the y tem, an

v to protect this line from I being norms LINE swrrcn.

1925. Serial No. 28,995.

through a connector scriber.

switch to called sub In Fig; 2 is showna similar system; the

subscribers substation A, theline switch ranged to. operate with a common inter- 'rupter I, wh leiin the line switch LS",t-he

stepp ng magnet has its individual inter-I rupter springs, and accordingly,- I v Having given a general explanation of the 1nvention and the apparatus. involved, the operation of the equipment will now befexthecircuits are adapted plained more indetail. For this-purpose it will; be assumed thatthe subscriber at substation A desires connection with some other subscriber 1n the exchange. To initiate" the PATENT F BERNARD n, wILLis, ior'onroaqo, inmnors esslonon, BYMES assrcirnimn'rs, To

call, the subscriber atsubstation A removes his receiver. Removing the receiver at substation, A places a direct current bridge across theline conductors 2zan'd 3, thereby 1 closing a circuit for the line relay 5 of the line switch LS. This circuit may be traced from the grounded resting contact and armature 10, line conductor 3, through the substation A, line conductor 2, armature 7 and the resting contact, through the winding of line relay 5 to battery; The wipers 23, 24, 25 arenormally resting on the home-position contacts 20, 21, 22, respectively. Upon the energization of'line relay 5, at armature l1 and the Workingcontact ground is placed on the private normal conductor 16 connected to the private contact in the connector banks connected with by some other callingline. A circuit is also completed from ground by way of rmature l1 and the working contact, homeposition contact 21, wiper 24:, working contact and armature 12," through the lower winding ofthe switching relay 4 to battery.

The upperwinding of switching relay t is adjusted so that armature 12 and its Working contact close before armature 11 and 1ts working contact close. This is to assure the proper-partial operation of switching relay 4 at this time. A circuit is now completed :for the stepping magnet 6 from ground by way of armature 11 and the working contact, armature 9, contact springs 18 and 17,

through the winding of the stepping magnet 6, to the interrupter I. which supplies interrupted battery. The interrupter I, as indicated by the small arrows to either side otthe conductor connecting the interrupter to the magnet 6, is common to a plurality of line si'vzitches such as LS. As long as this circuit is maintained complete, the stepping magnet will energize and deenergize in response to interrupted battery from interrupter 1. The stepping magnet is arranged to rotate the switch wipers on its return stroke, 'i. e., when it deenergizes. the first deenergization of steppingmagnet (t the wipers 23, 24, 25 are rotated oi? the home-position to the next set of bank contacts. Cam 14 also rotates and closes springs 13 thereby preparing the return stepping circuit to be described later. If thefirst selector accessible at this set of contacts is busy, there will be ground on the private contact engaged by the private wiper 24 and the ground will be maintained on the junction of the upper and lower winding of the stepping relay 4. The circuit for the stepping magnet 6 is still maintained and on the next dcenergizationot the magnet the wipers will be rotated to thenextset of bank contacts. This stepping action will continue until the wipers 23, 2 t, 25, engage a set of contacts leading to an idle selector switch, the. idle condition being indicated by no ground present on the private contact.

It will be assumed that selector S, accessible at the line switch bank contacts 26, 2?. 28. is the first idleselector found. Under this condition there is no ground on bank contact 37 and the upper winding of switching relay 4 is no longer shortcircuited and the relay will energize completely. In op-v erating fully, armature 9 completes its stroke, separates springs 18 and 17 and makes contact with both springs 18 and 19. The circuit of the stepping magnet is thus opened and as a result the wipers 23, 24, E remainengaged with'the bank contacts leading to selector .The complete energization of switching relay 4 also results in the opening of a point in the return-stepping circuit, to be described later, at armature 8, and in the operation of armatures 7 and 10 which disconnects theline conductors 2 and 3 from the line relay 5 and ground, and connects themby way of wipers 23 and 25, bank contacts 26 and 28, armatures 33 and 35 andthe resting eontacts,through the upper and lower windings of the line relay 31 Upon of the selector S to battery and'ground, rcspectively.

The line relay 31 ot' the selector S energizes overthe above traced circuit and closes acircuit for the release relay 32 atarmature Release relay 32 operates and places ground on conductor 38 at arn1ature37 thereby supplying a holding ground for the switching relay shot the line switch LS and a protecting ground to conductor 16, by way or bank contact 27 and wiper 24:, before line relay 5 has had time to fall back.

The subscriber at substation A now dials the directory number of the substation with which connection is desired. Inresponse to the first digit dialled, the selector S raises its wipers to the proper level of bank contacts, corresponding to the digit dialled, and then rotates its wipers in search of'an idle trunk to a succeeding selector. In response to other digits dialled by the calling subscriber, other selectors operate in the well known manner, the number of selectors being determined by the size of the system. The operation of the succeeding switches-is well known in'the art and consequently need not be described. Responsive to the last two digits dialled, a connector *aises its wipers and then rotates them to connect to the called line, automatically signals the called subscriber and finally completes the talking connection when the called subscriber answers. The subscribers may then hold conversation.

At the termination of the conversation the subscribers will replace their receivers on their respective switch-hooks. Replacing the receiver at substation A opens the direct current bridge across the line conductors 2 and 3. As a result, the selectors are released, in the well known manner, and the holding ground removed from conductor 38. The switching relay 4: deenergized and its armature springs are restored to normal. A return-stepping circuit is now completed for the stepping magnet (3 from ground by way of arnniiture 11 and the resting contact, closed springs 13. the resting contact and armature 8, closed springs 18 and 17, through. the winding of the step ping magnet 63, to the interrupter I which supplies interrupted battery. The stepping magnet 6 will now operate to rotate the wipers 23, 24, 25 step-by-step in the forward direction until they reach the home-posi tion. 'At this position the cam 14 will again open the springs 13 thereby opening the return stepping circuit of the stepping magnet 6. Consequently, the wipers will remain resting in the home-position. The replacement of the receiver at the called substation effects the release of the connector as is well known and need not be discussed.

A brief explanation of the operation of line switch LS may now be given and for ill) initiate the call, the subscriber at substation AFremoves his receiver and dials the direc tory number of the substationwith which connection is desired. Removing the receiver at substation A places a bridge across the lineconductors 2 and 3 and, closes a circuit for the line relay 5 of the line switchLS';

Line relay 5 energizes and places ground on the home-position private contact 21, on the lower end of the winding of the switching relay 4-, and on the private conductor 16, at armature 11; and at armaturelZ closes a circuit for the stepping magnet 6. This circuit may be traced from ground on contact 21, wiper 2i, armature 9' and the resting contact, the working contact and armature l2, interrupter springs 15, through the winding oit thestepping magnet 6 to battery. Switching relay l isshort-circuitcd at this time'by ground on'both ends of its winding. Stepping magnet 6 energizes and, nearthe end of its stroke, opens its own circuit at the interrupter springs -15. Stepping magnet 6 thenreleases and in so doing rotates the switchwipers23, 2 L 25, off the home-position to the next set of bank contacts. Cam 14 alsowrotates and closes springs 13, thereby preparing the return stepping circuit to bedescribed later. If the selector accessible at this set of bank contacts is busy, the private contact engaged by the private wiper 24 willbe grounded and the circuit for the stepping relay 6 will again be completed and the wipers will be rotated to the next set of bank contacts. This stepping action will continue until the wipers 23, 24;, 25 engage a set of contacts connected to an idle selector. It will be assumed that selector S, accessible at bank contacts 26, 27, 28, is the firstridle selector encountered. Under this conditionthere will be no ground on contact 27', engaged by wiper 2 L. Relay 4; being no longer short circuited by ground on both ends of its winding, will be energized from ground by way of a rmat-ure 11 and the working contact, through the winding otswitching relay l", closed in terrupter springs 15, through the winding of the stepping magnet 6 to battery. The

stepping magnet does not energizeat this time on account of the high resistance of relay t. 'Upon energizing,.relay l prepares a holding circuit for itself at armaturefi, opens a point in the return stepping circuit to be described later atarmature 8, and at armatures 7 and 10 disconnect-sthe line conductors 2' and 3 from ground and line relay 5 and connects them to the'selector S as similarly described in? connection with the description of line switch LS.

The succeeding operations are also similar to those already described in connection with net is stopped.

the description of LS, and theytalking connection is; established in like manner \Vhen T the -subscribers.replace their recc-iversat the termination Of theficonversas tion, the selector switches areareleased;and

the holding ground removed from conductor 38?. Switching relay 4. I deenergizes and closes ytheireturn-stepping circuit at arma-, true 8. This circuit maybe traced from groundby wayof armature 1' 1- and the restingconta'ct, closed springs 13,armature 8' and theresting contact, closed interrupter springs 15, through thewinding ofthe stepping magnet 6 to battery. The wipers are rotated in a forwarddirection to the homeposition. At this position the return-stepping circuit is opened at springslfi by cam 14, thereby preventingfurther movement of the wipers. L 1

Having described; the invention, what is thought new and is desired to have protected by Letters Patent is set forth in the appended claims; r lVhat is claimed is: c i 1. In a selector switch, a marginal relay, means for partially operating said relay to start the switch, and means for completely operating said relay to stop the switch.

2. In a trunk selecting switch, a twostep magnet closed by said relay in its first step andopened inits second, means for operating said relay in its first step to start the switch hunting, and means lIlClUCllHg a-test circult for preventing the relay from operating in its second step until an idle trunk is found. i

3. In a trunk selecting. switch, a relay operable, in two stages, amotor magnet having acircuit closed by said relayin its first stage of operation, two windings for said relay, meansforenergizing one winding alone tooperate the relay in its first stage, whereby the operation 01. said magnet is initiated, and testing means for energizing the second winding also when an idle trunk is found, wherebythe operation of the mag- 4. In a rotary line switch, trunk line contacts, a home position contact, a test wiper, means including a circuit extending through said wiper and said home contact for enabling the switch to start hunting, meansin- [eluding a circuit throughgsaid wiper and busy trunk contacts for continuing the huntingoperation'until an idle contact is found, oii normal contacts, and acircuitincluding said oft normal contacts "for causing the switch to. resume its. movement and continue same until said wiper reaches said home contact again. r

5. In ajtelephone system, a plurality of line switches, each terminating in a subscribers l1ne,trunk llnesaccessibleto said line switchesin the banks thereof, means tor indicating a busy or idle condition of said trunk lines, an interrupted battery supply common to said line switches, means in each line switch operable from said interrupted battery supply for causing said line switch to connect to an idle one or" said trunk lines in response to a subscriber initiating a call, and means in each line switch including said second named means for causing it to restore to normal position at the termination of a call, said last named means also including normally closed switch contacts which are opened responsive to the selection of an idle trunk. 1

6. In a telephone system wherein electroresponsive means is provided for operating atrunk selecting switch, a two step marginal relay contacts of which are connected in a first operated position to establish a circuit to said means and in its second operated position to break the said circuit.

7 In a telephone system wherein electroresponsive means is provided for operating a trunk selecting switch, a two step marginal relay connected in a first operatedposition to establish a circuit to said means, in its second operated position to break the said circuit, and in its normal inoperative position to establish a circuit for said means provided the switch is in any position other than one certain position.

8. In a telephone system wherein electroresponsivc means is provided for operating a trunk selecting switch, a two step marginal relay contacts of which are connected in a first operated position to establish a circuit to said means and in its second operated position to break the said circuit, and means for preventing the operation of said relay into its second operated position until an idle trunk is reached. l

9. In combination, a motor magnet, a switch controlling the circuit of said motor magnet, means for partially operatingsaid switch to close a circuit to said motor magnet, means moved under the control of said magnet to cause the complete operation of the switch to break the circuit to said motor magnet.

10. In combination, a motor magnet, a switch controlling the circuit of said motor magnet, means for partially operating said switch to close a circuit to said motor magnet, means moved under the control otsaid magnet causing the complete operation of the switch, means operated when the switch is completely operated to break the circuit to said motor magnet, and means effective upon the subsequent release of said switch to cause the second named means to return to its initial position.

11. In a telephone system, a trunk selecting switch including a motor magnet and a relay controlling. the circuit of said motor magnet, means for partially energizing said relay to close a circuit for said motor magnet, a trunk selecting wiper moved under the control of said magnet, said wiper causing the complete energization of the relay, and means operated when; the relay is completely energized to break thecircuit to said magnet. p

12. In a telephone system. a trunk selecting switch including a motor magnet and a relay controlling the circuit of said motor magnet, means ifor partially energizing said relay to close a circuit for said motor magnet, a trunkselecting wiper moved under the control of said magnet, said wiper causing the complete energization'ot the relay, means operated when the relay is completely energized to break the circuit to said magnet, and means effective upon the deenergization of said relay to cause the wiper to return to its initial position.

13. In a telephone system a line switch including a trunk selecting wiper having a home position, av line relay, a switching relay,a magnet for moving the wiper, off normal contacts open when the switch is in the home position and closed when the switch is in any other position, and an operating circuit for said magnet extending when the switch is away from the home position through two branches, one of said branches being controlled through said wiper and including a front contact on the line relay and back contact on the switching relay, the other branch including back contacts on each ofthc two relays and the off normal contacts. 1

14:. In a lincswitch oi? the homing type, a line relay, a switching relay, amotor magnet, a trunk hunting circuit for the magnet effective when the switch is away from the home position, said circuit including aback contact of the switching relay and a front Contact of the line relay, and a homing circuit for the magnet including said back contact of the switching relay, and a second back contact oi the switching relay in series.

'15. In a lineswitch of the homing type,

a line relay, a switching relay, a motor mag net, a trunk hunting circuit for the magnet effective when the switch is in an oft-normal position, said circuit including a back contact of the switching relay and a front contact of the line relay in series, and a homing circuit for the magnet including a back contact on the switching relay and a back contact on the line relay in series.

16. In a lineswitch of the homing type, a line relay, a switching relay, a trunk hunting wiper having a home position contact, a circuit for the magnet for initiating the trunk hunting movement of the switch, said circuit being controlled over said wiper and the home contact and including a back contact on the switching relay anda front contact on the line relay in series, otiqiorinal contacts, and a homing circuit for the n1agtrunk hunting movement of the switch, said circuit being controlled over said Wiper and the home contact of the switch and including a back contact on the switching relay and a front contact on the line relay in series, off-normal contacts, and a homing circuit for the magnet including said off-nor- 1nalcontacts, said back contact of said switching relay and a i ront contact of the line relay.

18. In a rotary line switch, a cut ofi relay, and a circuit for said relay extending through two setsof contacts on said relay in i series.

In Witness whereof, I hereunto subscribe my name this 6th dayof May, A. D., 1925.

BERNARD D. WILLIS.

Images