US2934607A

US2934607A - Selector

Info

Publication number: US2934607A
Application number: US629580A
Authority: US
Inventors: Clarence E Lomax
Original assignee: General Telephone Laboratories Inc
Current assignee: General Telephone Laboratories Inc
Priority date: 1956-12-20
Filing date: 1956-12-20
Publication date: 1960-04-26
Anticipated expiration: 1977-04-26

Description

C. E. LOMAX April 26, 1960 SELECTOR 2 Sheets-Sheet l Filed Dec. 20. 1956 NVENTOR,

CLARENCE E. LOMAX ATTY.

C. E. LOMAX April 26, 1960 SELECTOR 2 Sheets-Sheet 2 Filed DeC. 20. 1956 wss? .E5

INVENTOR.

CLARENCE E. LOMAX ATTY.

United States Patent O SELECTOR Application December 20, 1956, Serial No. 629,580 16 Claims. (Cl. 179-18) This invention relates to an improved control circuit for a step-by-step switch in general and, in particular, to an improvement in a vertical to rotary change-over control circuit of a step-by-step switch.

In the usual step-by-step switch of the two motion type, la line relay thereof is energized upon seizure of the switch and is then intermittently operated by a series of incoming impulses, corresponding to a digit, to step the switch in its primary direction to select a desired group of outlets corresponding to the number of impulses received. Means is then provided to promptly switch in another circuit to cause the switch to automatically select an idle outlet in the elected group.

In such switches a change-over relay of the slow acting type is usually used to switch in the circuit which causes the switch to automatically select an idle outlet after the primary movement has been completed.

Such a change-over relay is energized when the line relay starts its intermittent operation and is held operated during such operation and upon the completion of the intermittent operation is released as promptly as possible thereby completing the circuit for causing the automatic selection of the idle outlet.

As the number of received impulses will vary with the digit dialled and therefore the group elected, the slow acting relay must be held energized for different periods of time and still be promptly released at the end ofany series of impulses to promptly start the automatic selection so that adequate time is given for the selection of theidle outlet before another series of impulses is receivedwhich is to be sent over the selected outlet to another switch.

The usual slow acting relays are liable to release more slowly after having received a greater number of impulses than after having received only a few and thereforethere is the possibility of such a relay not always acting as promptly as desired and thus not giving suicient timefor the automatic selection of an idle outlet before the next series of impulses is received.

In order to overcome this ditliculty and standardize the time, after receipt of the series of impulses, when the change-over relay operates, I have provided an improved change-over relay which Will operate promptly and always within the same time period, independent of the number of impulses received by the line relay. This relay is a doublewound, differentially connected, slow-to-operate relay.

The purpose of this invention is to produce an improvement in the change-over of a step-by-step switch from primary to secondary motion by the use of a doublewound, dilerentially connected, slow-to-operate relay as the change-over control relay. I have illustrated the invention in connection with the well known step-by-step switch having vertical and rotary motion.

It is an object of this invention to provide a step-bystep switch that can change its motion from one direction to another in a constant period of time regardless ofthe number of steps taken in the rst direction.

It is another object of this invention to'provide a two motion switch which employs a doublewound, differentially connected control relay which causes the switch to change from its first to its second direction of motion.

It is still another object of this invention to provide a selector which can switch from vertical to rotary motion a fixed time after the vertical motion has been completed regardless of the number of vertical steps taken, thereby enabling the selector to perform the change-over in a shorter period of time.

It is another object of this invention to provide a selector which employs a doublewound, diiferentially connected relay as its vertical to rotary motion control, thereby enabling said selector to be changed from rotary to vertical motion in the same period of time regardless of the number of vertical steps taken, thus enabling the selector to `engage an idle trunk in a shorter period o f time than pres ent selectors.

This relay will get two pulses for each dial pulse. The pulses are delivered at alternate times and to two diiferent windings on the change-over relay. The windings are such that the field created by each winding is in an opposite direction to that created by the other. Therefore the windings are so arranged that they attempt to cancel each other. `This is the means employed for preventing magnetism from building up in the relay with each dial pulse.

Figure l is one embodiment of the invention and discloses the use of a doublewound, differentially connected slow-to-operate relay to cause a battery searching selector to change over from vertical to rotary motion. The relay in this embodiment has the vertical magnet connected in yseries with one of its windings. Figure 2 is another embodiment of the invention and discloses another method of using a doublewound, difierentially connected relay to cause a selector to change from vertical to rotary motion. In this embodiment the relay windings are energized through the contacts of the vertical magnet. However, only those components necessary ,todescribe this claimed embodiment are included as the other components necessary to complete the entire selector can be of the standard type which could readily be added by one skilled in the art.

Figure 3 is yet another embodiment of the invention and it also discloses only those components necessary to describe this claimed embodiment for the same reason.

In this embodiment the doublewound, dilerentially connected relay has a resistor inserted in series with one of its windings during a certain portion of the time when that winding is energized.

Figure l is a iive relay battery-searching selector switch containing a pulsing relay 1A, a holding relay 1B, a change over relay 1D, a switch through relay 1F, a stepping relay 1S, a rotary magnet lRM, a vertical magnet IVM, and a release magnet. l

When the switch is seized, relay 1A is energized and dial tone provided in a well known manner. Relay 1A upon operating closes an obvious circuit to ground for relay 1B at contacts 1A1. Relay 1B encrgizes: to prepare a circuit for the vertical magnet 1VM through the upper winding of relay 1D, at contacts 1B2 to complete a circuit from ground to the lower winding of relay 1S through resistor 1K1 at contacts 1B4, and to place ground on lead C through contacts 1B1 to mark the selector busy to all preceding switches. Relay 1S does not operate at this time because the field created by the lower winding is not strong enough to operate the relay. This is a method of pre-energizing relay 1S to make it operate quickly when the upper winding is energized.

If the calling party hangs up before dialing, relay 1A restores, but relay 1B being a slow-torelease relay remains closed for a period of time. During that period of time a pulse is sent to the vertical magnet 1VM which operates, from ground, through contacts 1F7, contacts vIAZ, contacts IDI, contacts 1B2, through the upper winding of relay ID, and through the vertical magnet 1VM to battery. `Relay ID is not operated through its upper winding but a magnetic field is builtup. The vertical magnet IVM is operated and steps the wiper of the switch one step in the vertical direction thereby causing the vertical-ol-normal contacts IVMZ and 1VM3 to be closed and the vertical-oi-normal contacts IVMI to be opened. Relay 1B thereafter restores, and at contacts IBZopens the vertical magnet circuit, and at contacts IBS closes the circuit to the release magnet. The release magnet is then operated `over an obvious path and then restores the selector in -a well known manner. Y

When the calling party starts dialing, relay 1A is restored by each dial pulse. When relay IA is restored by the rst dial pulse it closes a circuit to the vertical magnet IVM as has been described. The vertical magnet 1VM operates and opens its spring contacts IVMI, and steps the wiper of the switch one step in the vertical direction thereby closing the vertical-oi-normal springs IVM2 and IVMS and opening the vertical-offnormal springs IVMI. During the time that the vertical magnet IVM is operated, a current is owing through the upper Winding of relay ID but the eld created thereby is not sufficient to operate the relay. Relay l1B being a slow-to-release relay, remains operated throughout the pulsing of relay 1A.

Relay IA reoperates after the rst pulse and opens the circuit to the vertical magnet IVM and the upper winding of relay ID at break contacts IAZ, thereby causing the vertical magnet IVM to restore. 'Ihe vertical magnet upon restoring closes a circuit to the lower winding of relay 1D, from ground at contacts IB4,

"through break contacts IVMI of the vertical magnet,

contacts IVMS of the vertical-off-norrnal springs, through the lower winding of relay ID to battery.

The current through the lower winding of relay 1D is in the opposite direction to the current through the upper winding. The vertical magnet IVM is not restored long enough between pulses to operate relay 1D. The second pulse, which occurs when relay 1A restores again, operates the vertical magnet IVMI which opens its armature springs I, thereby opening the circuit to the lower winding of relay ID. -As has been pointed out when the vertical armature operates, current ows through the upper winding of relay ID. This current creates a iield which is opposite to that created by the lower winding. The purpose of the upper winding is to act as a cancellation winding for the lower winding so that the lower winding will not build up magnetism in relay ID due to the repeated pulses.

It should be pointed out at this time that the current starts flowing through the upper winding while current is still flowing through the lower winding since some time is required for the vertical magnet to operate after its energization circuit has been closed. Therefore the operating power for relay ID, that is, the field created by the current through the lower winding is reduced before the vertical armature moves, thus aiding the upper winding to more quickly dispose of the eld of the lower winding.

When relay 1A comes to rest in the operated position at the end of the dialled digit, the current through the lower winding of relay ID creates a eld which is energized long enough to operate the relay 1D.

As relay ID operates it opens another point in the circuit for its upper winding, the vertical magnet 1VM, and the release magnet, at contacts IDI. At contacts 1D2, it closes a holding circuit for itself from ground, through make contacts YIBi, through contacts IDZ, through the lower Winding of relay 1D to battery. At contacts 1D4, it prepares a circuit for relay 1S. At contacts ID3, it closes a circuit to the rotary magnet IRM from ground, contacts ID3, contacts ISZ, contacts IFS, the rotary cam springs 1, the rotary magnet interrupter contacts IRMI, and the rotary magnet IRM to battery. The rotary magnet energizes and rotates the shaft and its wipers to the rst set of bank contacts, and if no battery potential is encountered by wiper C', rotates the wipers to the next set of bank contacts and so on until an idle switch is found. The' rotary magnet opens its own circuit at contacts IRMI and thereby automatically rotates the shaft and wipers until an idle switch is found.

As soon as battery potential appears on lead 1C, indicating an idle switch, relay 1S is operated from ground, contacts 1D4, the upper winding of relay 1S to battery on lead IC.

Relay 1S when operated opens the circuit to the rotary armature at break contacts 1S2, and closes a cir cuit to relay IF, from ground, through the contacts ID3, and ISI to the winding of relay 1F and battery.

Relay 1F, upon operating, extends the calling line conductors, -L and --L, at contacts 1F2 and 1F4, respectively, and completes a holding circuit for itself from ground on the C lead at springs IBI extended, through contacts IF6 to battery. The seized switch which upon being seized also places a ground on the wiper extended over the contacts IFS and 1F6 to provide holding ground for relay 1F upon the release of the relay 1B.

Upon opening of the contacts IFI and IFS, the relay IA releases and opens the circuit to relay 1B at contacts 1A. Relay 1B restores and opens the circuit to relay 1D at conatcts 1B4 thereby releasing relay 1D, and prepares a circuit to the release magnet through the contact ID3 which does not operate until the relay 1F releases and closes its contacts IF7.

Relay 1D upon releasing, opens the circuit for relay 1S at contacts ID4. Relay IS then drops out leaving the switch through relay IF as the only relay operated. Relay 1F is released when the holding ground removed from lead wiper C. To close an obvious circuit to the release magnet at contacts 1F7 thereby causing the switch to be returned to normal in a well known manner.

Various arrangements of the change-over relay and the vertical magnet can easily be made without departing from the scope of this invention.

Figure 2 shows an arrangement comprising a modiiied form of the invention whereby the change-over relay 2D is energized through the springs of the vertical magnet. Both the vertical magnet and the change-over relay are in separate circuits. Only those components necessary to describe this embodiment of the invention are shown and the remainder of components necessary to complete the entire selector can be of the standard type which can be readily added by one skilled in the art. s

Figure 2 contains a pulsing relay 2A, intermittently operated by a series of impulses such as those caused by the operation of a dial, holding relay 2B, which is a slowto-release relay, relay 2D, which causes the change-over from vertical to rotary motion after the completion of the series of impulses to the pulsing relay, a vertical magnet ZVM, a rotary magnet 2RM, and a release magnet.

When the calling subscriber initiates the call the pulsing relay 2A is energized in a well known manner, and completes an operating circuit to relay 2B from ground, extending through contacts ZAI, and the winding of relay 2B to battery. Relay 2B upon operating prepares a circuit to the vertical magnet ZVM by closing the contact ZBI.

When relay 2A restores in response to the tirst pulse, relay 2B being a slow-to-release relay stays operated during the restoration of relay 2A and a circuit extending to the vertical magnet is closed, from ground, through contacts 2A2, 2B1, 2D1rotary cam springs 21 tobattery.

The vertical magnet operates and steps the switch one step in the vertical direction thereby closing the verticaloff-normal springs 2VM3.

vmake contacts 2VM1, to

The vertical! magnet then closes its spring contacts 2VM1 thereby completing 'a circuit to the upper winding of relay 2D, from ground, through the vertical-off-normal springs 2VM3, armature battery. K d

The current flowing through the upper winding of relay 2D is not sufficient to create a field capable of operating the relay.

Relay 2A then re-operates after the first pulse and opens the circuit to the vertical magnet ZVM at its contacts ZVMZ. The vertical magnet then restores and opens the circuit to the upper winding offrelay 2D at contacts 2VM1, and closes a circuit to the lower winding of relay 2D at contacts '2VM2, from ground, through the verticaloff-normal contacts 2VM3 and 2VM2 through the lower winding of relay D, to battery. Thus current is caused to flow in the lower winding of relay 2D. The field produced in the lower winding of relay 2D is opposite to field in the upper winding.

The Vertical magnet ZVM is not restored long enough between pulses to operate relay 2D. Thel second pulse which occurs when Vrelay 2A restores responsive to the series of impulses operates the vertical magnet ZVM as has been explained, thereby closing its contacts 2VM1 to again energize the upper winding of relay 2D, and opens the circuit to the lower winding of relay 2D at contact 2VM2. The field created by this upper winding of relay 2D is Aopposite toy that created by the lower winding of relay 2D and tends to cancel the lfield remaining in the lower winding. The purpose of the upper winding is to act as a cancellation winding for the lower winding so that the lower' winding will not build up magnetism in the relay due to the repeated pulsing.

After the end of the dialed digit the current through the lower winding is not interrupted and, after the counter effect of its upper winding ceases, relay 2D energizes, Yand upon operation closes a circuit for the rotary magnet 2RM, from ground, extending'throu'gh the contacts ZDZ and the interruptor contacts 2-RM2 and rotary 4magnet to battery. The remainder of the operation can be conventional 'and is not pertinent to this embodiment of the invention. p

Still another embodiment of the invention is shown in Figure 3. Figure `3 like Figure 2 is not a complete drawing of afstep-by-step switch such as Figure 1 wherein the invention is shown as applied to a selector. One skilled `in the a'rt would have no difficulty in adding the necessary components to complete the entire selector since the omitted components can be of the standard type.

Figure 3 contains a pulsing relay 3A, a holding relay 3B, a change-'over relay 3D, a vertical magnet SVM, and a rotary magnet SRM. p n

When a calling subscriber initiates a call, the pulsing relay 3A is seized in awell known manner. When relay 3A operates it closes a` circuit to the holding relayl 3B from ground, through contacts BA1 and winding of relay 3B to battery. d

Relay 3B is a slow-to-release relay and stays operated during the intermittent operation of relay 3A which is operated responsive to the dial pulsing of a dialed digit. Relay 3B upon venergizing prepares a circuit to the changeover relay 3D and the vertical magnet 3VMat contacts BB3.

When relay 3A lrestores responsive to the 'rst dial pulse it closes a circuit towboth the vertical magnet SVM and the upper winding of the change-over relay 3D, from ground through the contacts 3 A2 of relay 3A, contacts 3B3, contacts 3D4, contacts SVMS and the upper winding of relay 3D t'o battery and through the vertical magnet SVM to battery. The upper winding of the change-over relay could operate the relay'except that resistor R1 is placed in series with the 'upper winding near the end of -the armature stroke when contacts SVMS open. The current is also cut down to the vertical magnetby the insertion of the resistorSRlbut the momen-y relay 3D is again closed as Yturn of the shaftitself operated by thevertical'magnet wouldfcause the'shaft to finish its stroke. Y 1

The vertical magnet SVM causes the switch totstepv off normal and close a circuit to the lower, or operating winding of relay 3D from ground, to the vertical-'olfnorrnal contacts 3VM7 and 3VM6, and through the lower winding of relay 3D to battery. However, contacts 3VM6 of the vertical magnet are so arranged that they open at the beginning of the stroke and the circuit therefore has no effect on the operation of relay 3D at this time. p

When relay 3A reoperates during its intermittent operation it opens the circuit to the vertical magnet BVM and upper winding of relay 3D. The vertical magnet restores and closes a circuit to the lower winding of relay 3D which is the operate winding, from ground, 3VM7 and BVM6, through the lower winding of relay 3D to battery. The current through the lower winding of relay 3D does not have time to operate the relay during pulsing of relay 3A. The magnetic field created by the lower winding is opposite to the magnetic field created by the upper winding. The circuit to the upper winding of has been described.y The purpose of the upper winding of relay 3D is to act as a cancellation winding for the lower winding which is the operate winding to prevent magnetism from building up in the relay due to the pulsing. K

In this embodiment of the invention the initial surge to the cancellation winding is relatively larger than in the other embodiments discussed and would not only cancelthe'operate field still remaining but would operate the relay itself. However, a resistor SR1 is inserted lin series with the upper winding near the end of the vertical stroke of the vertical magnet and the field of the upper winding is thereby decreased.

The purpose of theresistor is to enable a strong field to be created in the first winding of relay 3D without operating relay 3D.k The pulsing relay 3A is intermittently operated responsive to a received number of impulses thereby. There is no assurance that every rseries of impulses will have pulse lengths of equal length. The worst condition in 'as far as this design is concerned is when the pulse length is short to the pulsing relay thereby causing the pulsing relayto be released a smaller 'percentage of the time than it is operated during the intel'- mittent operation.

This shorter release time of the pulsing relay will cause the second winding of relay 3D to be energized a longer period of time and therefore require a stronger field in the first winding of relay 3D to eliminate the buildfup of magnetism in the relay.

Therefore in order to create as strong a field as practical in the first winding of relay 3D without operating relay 3D a resistor has been inserted to reduce the field of the lfirst winding before the first winding can operate the relay.

It can now be seen that the alternate pulsing of Vthe two windings of the change-over relay 3D during the dialing of the digit by the calling party eliminates magnetism from being built up in the relay and enables the relay to be so wound that a considerable amount of time can be saved in transferring the vertical motion of a step-by-step switch to rotary motion.

What has been described are considered to be the preferred embodiments of the invention and -it is to be further understood that other modifications both in structure and manner of operation may be made without departing from the scope of my invention as defined in the vclaims which follow.

What is claimed is:

l. In a selector switch having pulse responsive means for stepping a wiper in a vertical and rotary motion, a vertical to rotary motion change-over control relay, a first and a` second winding on said relay, first circuit means operable during the vertical stepping of said wiper or energizing :indue-energizing said first windi'rigof -said first winding of said relay,

stepping, thereby enabling said relay to operate at a constant period of time after the vertical stepping of .said wiper has been` completed regardless of the number -of vertical steps said switch wiper has'taken.

2. -A step-by-step'selector switch as claimed in claim l wherein said firstcircuit means and said second circuit means, operable duringthe vertical stepping of said wiper for energizing and de-energizing said first winding and vsaid second winding of said relay, energizeand de-energize said first winding and said second winding once for each vertical step of said wiper.

3. In a step-by-step switch as claimed in claim 1 wherein said rst circuit means, operable during the vertical stepping of said wiper for energizing and de-energizing comprises a pulsing relay, a slow-to-release holding relay, and a vertical magnet connected in series with .the first winding of said control relay, said pulsing relay causing the operation of said holding relay upon initial operation of said pulsing relay, subsequently said pulsing relay being intermittently operated responsive to a series of impulses received thereby, said holding relay remaining operated during said intermittent operation of said pulsing relay thereby enabling said pulsing relay to cause said first winding of said control relay and said vertical magnet to be energized and de-energized, each energization of said vertical magnet causing said wiper to be stepped one step.

4. A step-by-step switch as claimed in claim 1 wherein said second circuit means, operable during the vertical stepping of said wiper for energizing and de-energizing said second winding of said control relay, comprises a pulsing relay, a slow-to-release holding relay, and a ver tical magnet connected in series with said first winding of said control relay, said pulsing relay causing the operation of said holding relay upon initial operation of said pulsing relay, subsequently said pulsing relay being intermittently operated responsive to a series of impulses received thereby, said holding relay remaining operated during said intermittent operation of said pulsing relay thereby enabling said pulsing relayy to cause said first winding of saidcontrol relay and said vertical magnet to be intermittently energized, each energization of said vertical magnet causing said wiper to be stepped one step, each deenergization of said vertical magnet causing said second winding of said control relay to be energized.

5. A selector switch having a pulse responsive means for stepping a wiper in a vertical and rotary motion comprising a pulsing relay having a set of make and break contacts operated thereby, a slow-to-release holding relay having a set of make contacts operated thereby, an operate path for said holding relay completed by said make contacts of said pulsing relay in response to the operation of said pulsing relay, a vertical to rotary motion changeover control relay having a first and second winding, a vertical magnet connected in series with said first winding, said magnet having a set of break contacts operated thereby, an energization path for said first winding and said vertical magnet completed through said break contacts of said pulsing relay and said make contacts of said holding relay responsive-to the release of said pulsing relay and the operation of said holding relay, an energization path for said second Winding completed through said break contacts of said vertical magnet upon release of said vertical magnet, said pulsing relay upon initial 'operation causing said holding relay to be operated, said pulsing relay subsequently being intermittently operated responsive to a series of impulses received thereby and remaining operated thereafter, said holding relay remaining operated during said series of impulses to said pulsing relay, said energization path for Ysaid first winding and said vertical magnet and said energization path of said second winding alternately closed responsive to each release and operation of said pulsing relay, said energization path for said first winding and said vertical magnet being completed when said pulsing relay is released, through said break contacts of said pulsing relay and said make contacts of said holding relay, said vertical magnet causing said wiper to be stepped one step responsive to each successive energization of said vertical magnet, said energization path for said second winding being completed when said vertical magnet is released through said break contacts of said vertical magnet, said first and said second winding upon being energized producing magnetic fields which oppose each other and thereby eliminate any build-up of magnetism in said control relay as said pulsing relay is intermittently operated, said energization path for said second winding remaining completed after said intermittent operation of said pulsing relay to thereby operate said control relay, said operation of said control relay causing said wiper to change from vertical to rotary motion, said elimination of said magnetic build-up in said control relay and said completion of said second winding after said intermittent operation, enabling said wiper to change from vertical to rotary motion a fixed period of time after the last impulse has been received by said pulsing relay regardless of the number of impulses in said series of impulses.

6. A selector switch having pulse responsive means for stepping a wiper in a vertical and rotary motion comprising, a pulsing relay, a slow-to-release holding relay, a vertical to rotary motion change-over control relay having a first and a second winding, and a vertical magnet, said pulsing relay upon initial operation causing said holding relay to be operated, said holding relay thereafter preparing a circuit to said vertical magnet, said pulsing relay subsequently being intermittently operated in response to a series of impulses received thereby and remaining operated thereafter, said holding relay remaining operated during said impulsing, said pulsing relay causing said vertical magnet to be intermittently operated responsive to the intermittent operation of said pulsing relay thereby causing said wiper to be vstepped in the vertical direction, said vertical magnet upon operation during said intermittent operation causing said first winding to be energized and upon release of said vertical magnet causing said second winding to be energized, both windings producing magnetic fields which oppose each other thereby preventing the build-up of magnetism in said control relay during said stepping of said switch, said vertical magnet after vertical stepping has been completed causing said second winding to remain energized to thereby operate said control relay to cause said switch to change from vertical to rotary stepping, said elimination of said build-up of magnetism in said relay and said cornpletion of said second winding after said intermittent operation, enabling said wiper to change from vertical to rotary motion a fixed time after said last impulse is received by said pulsing relay regardless of the number of impulses in said series.

7. In a selector switch having wipers and a magnet for moving said wipers in a primary movement and means for moving said wipers in a secondary movement, a pulsing relay energizesd when said switch is Yseized, said pulsing relay thereafter intermittently operated in response to received impulses to operate the wipers in their primary movement, a change-over relay having a first and a second winding, means controlled by the intermittent operation .0f Said pulsing relay for. .intermittently closing y9 a circuit for said magnet and said first winding to thereby intermittently operate said magnet to move said switch in said primary movement and intermittently energize said first winding, and means controlled by the intermittent operation of said magnet for intermittently closing a circuit for said second winding during receipt of said impulses and for maintaining said circuit for said second winding closed thereafter, the fields created in said change-over relay during said intermittent energization of said windings opposing each other to prevent any build up of magnetism in said change-over relay during said intermittent energization, said continued energization of said second winding afterpthe completion of said intermittent pulsing and said elimination of any build up of magnetism in said change-over relay thereby enabling said relay to operate a predetermined period of time after the cessation of said impulses to thereby cause the operation of said means for moving the wipers in said secondary movement a fixed period of time after the completion of said impulses to said pulsing relay.

8. In a switch having a movable wiper means responsive to the recepit of impulses for selectively stepping said wiper in a primary or secondary movement, means for transferring said stepping means from primary to secondary motion, comprising: a differentially connected relay having a 1st and 2d winding first; circuit means for creating a field in said first winding; second circuit means for creating an opposing field in said second winding, said first and second circuit means each actuated once for each step of said switch in the primary movement; means responsive to cessation of said received pulses for rendering said first circuit means ineffective and enabling said relay to operate a fixed time following said cessation; and means controlled by the operation of said relay for transferring said stepping means from the primary movement to the secondary movement.

9. In a two-motion switch; having a wiper means operated responsive to the receipt of impulses for stepping the wiper; a differentially connected relay having two windings; circuit means for energizing each of said windings once for each step of said wiper; means for causing said relay to operate a predetermined time after cessation of said pulses to said stepping means; and means controlled by the operation of said relay for enabling further operation of said switch.

10. In a two-motion switch having a movable wiper; means responsive to the receipt of impulses for selectively stepping said wiper in a primary or secondary movement; a differentially connected relay having a pair of windings, said windings being so constructed as to produce opposing fields when energized; circuit means for energizing each of said windings once for each step of said switch in the primary movement; means responsive to cessation of said received pulses for controlling said circuits means and enabling said relay to operate at a fixed time thereafter; and means controlled by the operation of said relay for transferring said stepping means from the primary movement to the secondary movement.

11. In a two-motion switch having a movable wiper; means responsive to the receipt of impulses for sequentially stepping said wiper in a vertical and rotary movement; a relay having two windings each of said windings being constructed as to produce a field which, when energized, opposes the field produced by the other winding; circuits means for energizing each of said windings once for each step of said wiper in the vertical direction; means responsive to cessation of pulses tosaid switch for controlling said circuit means and enabling said relay to operate; and means controlled by the operation of said relay for transferring said stepping means from the vertical movement to a rotary movement, whereby the windings of said relay are energized to produce the vertical portion of the wiper movement and energizing current to one winding is discontinued upon cessation of the pulses to enable said relay to operate at a fixed time -after such cessation.

1`2. In a two-motion switch having a movable wiper means operated responsive to the receipt of impulses for stepping said wiper in vertical or rotary movement; a relay having a pair of windings; circuit means for alternately energizing each of said windings once for each step of said switch in the verticaly direction, each of said windings operable upon energization to cancel the effect of any residual magnetism in the other winding; means responsive to cessation of said pulses for controlling said circuit means to discontinue energization of one of said windings to 'enable said relay to operate a `fixed time thereafter; and means controlled by the operation of said relay for transferring said stepping means from a primary movement to a secondary movement, whereby said relay is prevented from operation by the build-up of residual magnetism therein and is operated a fixed time after the cessation of pulses to the stepping switch without regard to the number of pulses received by said switch.

13. In a twomotion switch having a movable wiper; means responsive to the receipt of impulses for selectively stepping said wiper in a primary or a secondary direction; a relay having a pair of windings each winding being so constructed that the field produced therein, when energized, opposes the field of the other winding; circuit means for energizing each of said windings once for each step of said wiper in said primary direction; means responsive to cessation of pulses to said stepping means to control said circuit means and enable said relay to operate a fixed time after cessation; and means controlled by the operation of said relay for transferring said stepping means from the primary movement to the secondary movement, whereby the opposed windings of said relay prevent operation thereof prior to cessation of the pulses to said stepping means and prevent build-up of residual magnetism so that said relay operates a fixed time thereafter.

14. In a selector switch having pulse responsive means for stepping a wiper in a vertical and rotary motion, means independent of the number of pulses in a series, operable a fixed time after cessation thereof for transferring the wiper stepping means from vertical to rotary motion, comprising; a vertical to rotary motion changeover control relay having a first and second winding; a vertical magnet connected in series with the first winding of said control relay operable to step said wiper in a vertical direction one step for each operation thereof; a pulsing relay included in said pulse response adapted to receive pulses and be intermittently operated thereby; a slow-to-release holding relay operated and held operated by the operation of said pulsing relay; a first operating circuit for energizing said first winding to create a magn netic field therein and said vertical magnet, said circuit including a normally open contact on said holding relay and a normally closed contact on said pulsing relay for energizing said vertical relay and said first winding for each intermittent operation of said pulsing relay; a second circuit actuated under control of said pulsing relay to energize said second winding to create a magnetic field therein which is opposed to the magnetic field in said first Winding to prevent operation of said control relay by the build-up of a magnetic field in said first winding, whereby said second winding is unopposedly energized only upon cessation of pulses to said pulsing relay.

15. A selector switch having a pulse responsive means for stepping a wiper in a vertical and rotary motion, comprising: a pulsing relay, included in said pulse responsive means, having a set of make and break contacts operated thereby; a slow to release holding relay having a set of make contacts operated thereby; a vertical magnet intermittently energized by operation of said pulsing relay to step said wiper in a vertical direction once for each pulse received thereby, said magnet having a set of make and a set of break contacts operated thereby;

, 11 an operating circuit'including the rnaln'contactsY on said pulsing relay for intermittently supplying energizing current toV said holding relay to 4operate' said relay and hold it operated throughout the operation of said pulse responsive means; a vertical magnet operatingcircuit conditioned through the make contact on said holding relay and operated through the break contact on said pulsing relay; and a vertical to rotary motionl changeover control relay having a rst Winding energized through the closure of the make contact on said vertical magnet, and a second winding energized through the break contact on said vertical magnet, said first and second winding each creating a eld opposed to the other upon energization `to neutralize the magnetic elds created therein, whereby said relay is held against operations by said tirst winding during the receipt of impulses and is operated by said second winding upon cessation of the pulses.

16. The switch of claim 13 wherein the circuit means for transferring the stepping means from Yprimary to secondary motioncornprises; an operating circuit including make contacts operated by said pulsing relay to supply energizing current to said holding relay during'receipt of impulses; a parallel circuit including a vertical magnet and theA rst winding of control relay; a resistor circuit on said diterentially connected relay connected in series with said parallel circuit, said circuit including a resistor and anormally opened contact adapted to be closed'by a'predetermined amount of operation of said vertical magnet, whereby the time of maximum energization of said first winding is controlled to prevent build up of suiiicient eld therein to cancel the maximum field in said second winding.

References Cited in the le of this patent UNITED STATES PATENTS 2,529,402 Lomax Nov. 7, 1950 2,529,409 Newstedt Nov. 7, 1950 2,575,842 Rudeforth Nov. 20, 1951 2,663,763 Lomaxv Dec. 22, 1953 2,731,515 Wicks Jan. 17, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF rC()RR1ELCTIO1\I Ratent No. 2,934,607 April 26, 1960 Clarence E. Lomax It is hereby certified that error appears in the-printed specification of the above -numbered patent requiring correction and that the said Letters Patent should read as corrected below.

I Column 9, line 73, after "produce" insert opposing fields to prevent operation of the relay during Signed and sealed this 31st day of January 1961.

(SEAL) Attest: KARL f1. AXLINE i ROBERT c. WATSON y"'Attesting Officer Commissioner of Patents Ratent No. 2,934,607

UNITED STATES PATENT OFFICE CERTIFICATE 0E coRREcTToN April :26l 1960 Clarence E. Lomax pears in theprinted specificationl It is herebr certified that error ap rrection and that the said Letters of the above numbered patent requiring co Patent should read as corrected below.

Column 9, line 73, after "produce" insert opposing fields to prevent operation of the relay during Signed and sealed this 31st day of January l96l (SEAL) Attest:

IARL n AXLNE I ROBERT c. WATSON Attesting Ofcer Commissioner of Patents