US2195884A - Switch control system - Google Patents

Description

April 2, 1940. c. w. DALZELL SWITCH CONTROL SYSTEM Filed Aug. 12, 1939 2 Sheets-Sheet l av .mw 6% N SQ mm Q v6 W w w E mfi WV mw GVV GWV c &w m m n w wsmfi} m W. mi 3w 0 Q a m g 0 mm. Wm Q 1111 ILF IL \J MN WW GNNJLIPWN K u w $9 Na W mm m w v w ma ell.

HIS ATTORNEY c. w. DALZELL' 2,195,884

SWITCH CONTROL SYSTEM Filed Aug. 12, 1939 2 Sheets-Sheet 2 April 2, 1940.

DaZ eZZ- INVENTOR HIS ATTORNEY Cla ence Q. WN RN iimm -f 111111 11% MN mm mm X g mm mm mm Patented Apr. 2, 1940 UNl-TED STATES ,ATENT OFFiCE 2,195,884 SWITCH ooNrRoL SYSTEM I Clarence W. Balzell, Belleville N. 3., assignor to The Union Switch & Signal Company, Swissvale, Pa, a corporation oi lennsylvania Application August 12, 1939, Serial No. 289,893

10 Claims' (Cl. 246-442 My invention relates to switch control systems for railway track switches, and has particular reference to improved systems of the class in which a selector conditions a railway track switch for operation by either remotely controlled power operating means or by local manual operating means. I

In switch control systems of the above class, a selector" is provided' for a switch operating mechanism and when set in a normal position permits operation of the associated switch by power operating means to a position of ccrrespondence with a polarized switch control relay which is'controlled by a control lever located in a remote control office, and which selector when set in a reverse position prohibits operation by power operating means and permits manual operation of the switch by means of a hand lever provided for the switch operating mechanism.

In connection with such dual control switch operating mechanisms, it is desirable to prevent automatic restoration of the switch by the power operating means to its position of correspondence with the switch control relay after the switch has been locally operated and the selector restored to its normal position. Thus, in the event that the switch has been manually operated to a position out of correspondence with the switch control relay, the restoration of the selector to itsnormal position will not cause the power operatingmeans to automatically restore the switch to the position corresponding with the relay, with the result that movement of the switch under the wheels of a train is-prevented in the event the switch is occupied when the selector is restored to its normal position.

Accordingly, an object of my present invention is to provide an improved system of the class described and incorporating means to insure against automatic restoration of the switch upon operation of the selector to its normal position after the switch has been manually operated to a position out of correspondence with the switch control relay. l

A further object is to provide an improved system of the class described and incorporating means eiiective when the switch has been manually operated, to establish remote control of the switch upon operation of a remote switch control lever.

An additional object is to provide an improved system of the class described and incorporating means providing control of a switch from a .remote point, andjwhich requires the provision of but two line wires from such remote point to the location of'the switch.

A still further object is the provision of an improved system of the class described and incorporating means providing control of a switch 5 from a remote point through the provision of i normally deenergized control line wires.

Another object is to provide an improved system oi the class described and incorporating means effective whenthe switch has been manually operated, to prev'entremote control of the switch until the remote control lever is moved to a position out of correspondence with the switch control relay;

A further object is to provide an improved systemof the class described requiring a minimum of apparatus for effecting the above and other important objects. j I

An additional object is to provide an improved system of the class described and employing circuit means controlled by the remote control lever for establishing remote control of a power operating means, and whichincorporates a circuit controlling contact operated toan open position when the selector is moved to condition the switch for manual operation, and which contact is restored to its normal closed position only after the selector is restored to its normal position and the remote control lever is moved to a position out of correspondence with the switch control relay.

Another object is to provide an improved switch control system forrailway trackswitches;

Other objects and advantages of my invention will be apparent from the following description taken in connection with the accompanying drawings.

I shall describe two forms of apparatus em+ bodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view of one form of an improved switch control system embodying my invention. Fig, 2 is a diagrammatic view showing a modified form of the system shown in Fig. l and also with a selector which operates a link 4.

When selector SL is in its normal position, as shown in the drawing, link 4 conditions the switch for operation by power switch operating means, designated by the reference character M, and when the selector is in its reverse position, link 4 conditions the switch to operation by manual operating means, here shown as a hand lever H.

Selector SL also controls a member 5 which rotates about a pivot 6 between a normal position as shown and a reverse position. Member 5 r is adapted to engage a contact controlling memher I, pivoted about 6, to move the latter member from its normal position as shown into a reverse position. Member 'i in its reverse position engages a, contact member 8 to move member 8 out of engagement with a contact member 9 and thereby open a normally closed circuit controlling contact 8-9 formed by the two contact members. Contact controlling member 1 is biased by any suitable means, such, for example, as a toggle l0, into its last operated position, so that once operated by selector SL to its reverse position, selector SL may be restored to its nor mal position but member T is retained in its reverse position by virtue of the action of toggle I6, thereby holding contact member 8 out of engagement with contact member 9 until such time as member 7 is actuated against its bias into its normal position. Contact members 8 and 9 are biased into mutual engagement with the result that when member 7 is restored to its normal position, circuit controlling contact 8-9 also is restored to its normally closed position by virtue of the bias of members 8 and 9.

Member I also is controlled by a reset magnet RM having an armature H which at times engages contact controlling member 'I, the arrangement being such that when contact controllin member I is in its reverse position and armature H in its released position, the energization of magnet RM and consequent operation of its armature l l to its attracted position operates member 7 against its bias into its normal position, thereby permitting contact 89 to become closed. Preferably, the forces exerted by selector SL and the armature of magnet RM are selected and proportioned in such manner that selector SL, when operated into its reverse position to force contact controlling member '5 into its reverse position, exerts a force upon member 1 which exceeds the force exerted upon member I by armature H. Selector SL in its reverse position accordingly holds contact controlling member I in its reverse position against the energization of magnet RM, and prevents armature ll of magnet RM from moving to its attracted position in the event that magnet RM is energized during the interval that selector SL is in its reverse position.

Magnet RM also is provided with a normally open contact l2-l2a which becomes closed only when the associated armature H is operated to its attracted position. It can be seen that during the interval selector SL is in its reverse position, contact l2l2a of magnet RM cannot be closed if magnet RM is energized, since the associated armature l l of the magnet cannot be operated to its full attracted position, due to the fact that contact controlling member 1 (which is held in its reverse position by selector SL) engages armature H and prevents movement of the armature to its full attracted position.

The power switch operating means of mechanism SM,-hereinbefore referred to, is illustrated in the drawing as a switch movement of the type having a reversible electric motor M which comprises an armature l3 and a field winding id, but it is contemplated that other types of switch movement, such for example, as the type provided with a pneumatic motor, may be employed if desired.

Remote control of switch mechanism SM is established by means of a control lever E, which may be a switch control lever of an interlocking machine and which is generally positioned at a point remote from the location of switch SM. Lever E preferably is a manually operable circuit controller of the type operable to two extreme positions and biased to an intermediate position. As is readily apparent from an inspection of the drawing, lever E operates as a pole changer to supply line wires l5 and i8 (which extend from the position of lever E to the location of switch S) with current of one polarity or another from a suitable source of current, such as a battery not shown in the drawing but located adjacent the switch control lever and having its two terminals designated by the reference characters B and C. Normally, with lever E in its mid position, the wires I5 and I6 are deenergized.

In accordance with the polarity of current supplied to wires l5 and I6, one or another ,of two switch operating relays NWR and RWR is adapted to be controlled through the medium of a polarized switch control relay PR mechanically interlocked with a neutral relay NR in such manner that relay PR is permitted to reverse its polar contact only after neutral relay NR is energized and operates its associated armature to its energized position.

Polarized switch control relay PR comprises, as shown, a magnet l'l having two windings Ila and Nb and a polarizing winding [8, which latter winding preferably is provided with a permanently magnetized core l9. Mounted on core 19 is an armature 20, the arrangement being such that when windings Ila-I'll) are supplied with current of one polarity, armature 20 is operated in a counterclockwise direction to a normal position, that is, the position illustrated in Fig. 1, but that when current of the opposite polarity is applied to windings l7allb, the armature is then swung in a clockwise direction to a reverse position. In either event, energization of winding :8 is effected to strengthen the permanent magnetic field and thereby increase the polarizing action of core l9. Armature 20 of relay PR is operatively connected with a, polar contact member 2!, which is operated to a normal position when armature 20 is in its normal position, to close normal polar contact ZD-Zl. When armature 20 is swung to its reverse position, contact member 2| is swung to a corresponding reverse position and closes reverse polar contact 2l-'23.

Neutral relay NR controls a pivoted armature 24, the lower end of which projects into the path of movement of a portion of armature 20 of relay PR to prevent movement of the latter armature when relay NR is deenergized. Armature 24 of relay NR carries contact fingers 25a and 25b adapted to close front contacts 262'! and 28-29, respectively, when relay NR is energized. Contact finger 25a also closes a back contact 30-3I when relay NR is deenergized.

It should be pointed out that the polarized switch control relay usually is positioned adjacent its associated track switch, and hence is subject to relatively severe jars and shocks due to railway trafiic moving over or adjacent the switch. It is readily apparent, however, that with 2gl9fig88-k which. may be, traced from terminal B throughagainst and avoiding-improper operation of theswitch due to an accidental reversal of the switch.

control relay contacts. t v

The reference character J designates aswitch cirouitcontroller comprising a movable contactmember 32 operatively connectedwith switch S in the usual manner for movement between a normal position. (in Whichit. is. illustrated) and a reverse position.

all positionsof switch S except its fullnormal position, and also: engages another fixed contact member 34.. at. all positions or the switch except when the switch isin its-full'reverseposie tion.

The reference character OR designates an and a stick winding 36.

sistor 31, the function of which will be made i clear presently.

is closed, relays NR, PR, OR, NWR, RWR and magnet RM are all deenergized, motor M also is deenergized, and switch S and polar relay PR are in corresponding norinal positions.

I shall now assume that switch 5 is operated;

by-power to its reverse position. To do this,

lever E is actuated to its lower position (as viewed in the drawing) to connect wire l5- with the B terminal of the source of current over lever contact 38-40, and to connect'wire' it with A the C terminal of the source overlever contact Relay NR now becomes energized over" an obvious circuit and attracts its armature out of thepath oftravel of armature 26 of relay PR. The energizationof relay NR also closes front contacts 26-2'| and ZB-JQ, the closing of the last mentioned contact completing anobvious. circuit for winding l8 of relay- PR, which circuit is-supplied with energy; from a local source, such as a battery positioned adjacent the switch. The closing of front contact 25 -21 of relay NR completes anobvious circuitfor reset magnet RM, whereupon its armature H is attracted to its energized position and coin tact iii-12a is closed. This completes a circuit including the source of currentlocated adjacent lever E and the line wires I5 and I6, whereby windings lla-|'lb of relay PR are supplied with current of a polarity such tliat 'armaturezfl of relay-PR is operated to its reverse position. It should be noted that a resistor-43a and an asymmetrical unit 44w are connected in par allel with winding Ila and a-resistor-43b and an asymmetrical unit MD are connected in parallel with winding lib to improve the operation of relay PR.

Lever E may now be released, thereby interrupting the supply of energy to relays NR and PR, and relay NR releases its armature to-close back. contact 3fl.-3!', whereupon reverse operatingcrelayzRwR becomesenergized=over-acircuit Contact member 32' of con.- troller J engages a fixed contactmember 33 at back contact -3 I of relay NR, circuitcontrob ling;contact.8e9,.back.contact IE-45b ofrelay 9B,. reverse, polar contact, ll-23, of relay PR,

the-winding of reverse. switch. operating relay RWR and contact Sit-32. of controller J. (closed;

inrthe; normal. position of theswitch). to. termr- 1 nal C.

The energization of; reverse operating. relay RWR causes motor M to become energized. over. a. reverse operating circuit, which ext'endsirom terminal B through front. contact .46.-4Ga. of.

relay RWR, armature i3 ofmotor M, front con.-

tact 414la of relay RWR, field winding; IA of. -motor M and overload winding of'relay OR.

in parallel with resistor 3i, to terminal C. :The

polarity of energization of motor M is now such that the motor operates switch S to its reverse position, the circuit being maintained (unless mo tor M becomes overloaded) until the. switch reaches its full reverse positionwherein contact 32-'34. of controller J is opened. The opening of contact 32-3l of controller J interrupts the.

previously. traced circuit of relay RWR, whereupon the relay releases to terminate operation of motor M and switch S.

Winding 35 0f relay. ORand resistor 31' are so proportioned that under ordinary operating conditionsthe current division between the relay winding and the resistor when motor M is energized is such that. the energy level created in relay OR is insufiicient to. cause the relay to become picked up. However, in the event that motor M? becomes overloaded when operating switch S toits reverse position, as might occurif the switch strikesan obstruction or is blocked from moving to its full reverse position, the excessive current drawn by motor M under the latter condition causesresistor 3's to heat up and increase its resistance, thereby increasing thecurrent flow througlrwinding 35 and as a result the energizationof winding 35. increases to a point suchthat therelay picks up to open its back contact -451) and close-its front contact 45 -4541. The opening of back contact 45-451)- of relay OR interrupts the previously traced circuit of'relay RWR and as a result relay RWR re leases to terminate the operation of motor M. The closing of front contact" 45-450; of relay OR connects stick' windingtfi of relay OR in circuitwith back-contact Bib-3i of relay NR'and circuit controlling contact l -hand stick'winding 35 accordingly becomes. energized to hold relay OR'picked up until contact 3- -9 is opened, oruntil relay NR becomes energized.

When the switch is in its full reverse position, or'when it is'in a mid position and relay OR is held-picked up over its stick winding. 36, the switch may-be restored to its normal position by actuatingswitch control lever E in its upper di-:

rection (as viewedin the drawing). Wire Ifiis now connected with the B terminal of the source of current by lever contact air-42. while wire is connected with the C terminal by lever conof reset magnet RM closes, windings l'lai?b-of' relay PR-i'are supplied with current of a polarity such as to cause the relay to operate its armature to its normal position. Lever E may now be released, thereby permitting relay NR to become released and close back contact 30-31 to establish a circuit, which includes circuit controlling contact 8-9 and normal polar contact 21-22 of relay PR as well as contact 32-33 of controller J, for normal switch operating relay NWR.

The energization of relay NWR causes motor M to become energized over a normal operating circuit which may be traced from terminal B through front contact Mia-48 of relay NWR, armature 13 of motor M, front contact 49-4961. of relay NWR, field winding 14 of motor M, and overload winding 35 of relay OR in parallel with resistor 31, to terminal C. The polarity of energ'ization of motor M is now such that switch S is moved to its normal position. When the switch reaches its full normal position, contact 32-33 of controller J opens to interrupt the circuit of relay NWR whereupon that relay releases to terminate operation of motor M and switch S.

It should be pointed out that in the event mo- .tor M is controlled to operate switch S to its ,relay NR becomes energized due to an operation of lever E to pick up relay NR, or until selector SL is operated to its reverse position to open circuit controlling contact 8-9.

I shall now assume that with the apparatus 0f Fig. l in its normal condition (as illustrated),

selector SL is moved to condition the switch for hand operation, thereby opening circuit controlling contact 8-9. Switch S may now be operated to its reverse position by means of hand lever H. If, during an operation of switch S by lever H, lever E is operated in an attempt to remotely control the switch, such remote control is prevented by virtue of contact 8-9 which is held open by selector lever SL. Thus,althougha movement vof lever E to either of its extreme positions will cause relay NR to become energized and thereby control reset magnet RM to its energized condition, selector lever SL in its reverse position is effective to maintain contact controlling member ,1 in its reverse position against the energization of reset magnet RM, and also is eifective to prevent the closing of front contact 12-12a of magnet RM. Accordingly, windings Ha-IIb of relay PR remain deenergized since the energizing circuit for such windings is open at front contact 12-1211 of magnet RM, and as a result relay PR retains its armature in its normal position. Then, if lever E is released to its mid position so that relay NR becomes deenergized ,and closes back contact 311-31, neither of the two switch operating relays NWR and RWR can become energized, since the circuit for each of the relays is open at circuit controlling contact 8-9. It follows, therefore, that the construction ,and control of circuit controlling contact 8-9 by selector SL prohibits remote control of the switch during the interval the selector conditions the switch for manual operation. Also, the control of contact 12-12a of magnet RM by selector SL prohibits either relay NWR or RWR from being energized in response to an operation of switch lever E during the interval that selector SL conditions the switch for operation by hand lever H.

In the event that switch S is manually operated to a position out of correspondence with relay PR and the selector is restored to its normal position, the action of contact controlling member 1 in holding circuit controlling contact 8-9 open functions to avoid automatic restoration of the switch to its position of correspondence with polar relay PR. That is to say, when selector SL is restored to its normal position, contact controlling member 1 is held in its reverse position by virtue of the action of its toggle 10, with the result that contact 8-9 is held open. Accordingly, the circuit for normal operating relay l\WR which normally would be established with relay NR released and relay PR in its normal position while switch S is in its reverse position, is open at circuit controlling contact 8-9, and consequently automatic restoration of the switch to its position of correspondence with relay PR is avoided.

Relay PR may be restored to control of switch mechanism SM by actuating lever E to either of its extreme positions to cause relay NR to become energized. With relay NR energized, magnet RM also becomes energized to attract its armature 11 to its energized position, thereby closing front contact 12-12a. and operating contact controlling member I to its normal position to permit circuit controlling contact 8-9 to become closed. With contact 12-120. of reset magnet RM closed due to the energization of that magnet, relay PR will be operated to its normal or its reverse position according as lever E. is actuated to its corresponding normal or reverse position to supply wires 15 and 1G with current of normal or reverse polarity. If the position of lever E is such that relay PR is actuated to its position of correspondence with switch S, then when lever E is released and relay NR becomes deenergized, the apparatus will remain in its position wherein switch S and relay PR are in agreement. However, if lever E is actuated to control relay PR to a position out of correspondence with switch S, then when the lever is released and relay NR, becomes deenergized, switch S will be controlled to its position of correspondence with relay PR, in a manner pointed out hereinbefore.

From the foregoing description, it can be seen that the apparatus of Fig. 1 permits remote control of the switch by the switch control lever when the selector is positioned to condition the switch for power operation, and that when the selector conditions the switch for manual operation, remote control of the switch by the control lever is prohibited.

It is readily apparent that the control of circuit controlling contact 8-9 is such that if the switch is manually operated to a position out of correspondence with the switch control relay, automatic restoration of the switch to its position of correspondence is avoided when the selector is restored to its position conditioning the switch for power operation. It is also apparent that contact 8-9 is controlled to restore the apparatus for remote control whenever the switch control lever is actuated after the restoration of selector SL to its normal position. It follows, therefore, that apparatus embodying my invention provides a novel and improved switch control system for dual-control switch movements, and requires a minimum of apparatus to at times prohibit power operation of the switch and automatic restoration of the switch to its position of correspondence with the switch control relay.

In Fig, 1, the control linewires 15 and 16 are normally deenergized since lever E is biased to its mid position where the wires are disconnected from the source of current located at the lever, and the apparatus is arranged to operate during the. relatively short interval of time the lever is actuated to connect the source of current to the control wires. Because of the fact that the apparatus of Fig. l is caused to operate on a relatively short impulse of current, such apparatus is particularly well adapted for use in systems of the type known as Coded centralized trafi'ic control systems. In: such systems, control code impulses are supplied to normally deenergized line wires to effect operation of a switch or other trafilc controlling apparatus positioned at aremote point. When the apparatus of Fig. l is used in a system of the type mentioned,- the control impulse may be supplied by any of the usual and well-known code transmitting devices.

' In Fig. 2, a modification of the system shown in Fig. l. is shown wherein the control line wires are normally. connected in an open circuit with the source of current. Lever El of Fig. 2 is of the usual type movable between a normal and a reverse position and remains in its last operated position. The remainder of the apparatus of Fig, 2 is substantially similar to the apparatus of Fig. l previously described, except that two additional polar contact members 50 and 5| are controlled by relay PR to form normal polar contacts 5ll-52 and 5!-53 and reverse polar contacts EtL-M and 5l55, which are interposed in energizing circuits shortly to be pointedout for relay NR. Also, overload relay ORl of Fig. 2 is provided with a toggle controlled armature 58 which is operated from a normal into an operated position upon energization of overload winding 35 of relay OR! by current of overload magnitude, and

is retained in its operated position by virtue of the action of its associated toggle 5l' until a reset winding 53' provided for relay ORl is energized to attract it's own armature 59 into engagement with armature 56 to restore the latter armature to its normal position. Armature 56 of winding 35 controls a normally closed contact 6ll50a in such manner as to open that contact whenever armature 55 is in its operated position. Armature 59 of winding 58 controls a contact lit-6m to an open or closed position according as winding 58 is deenergi'zed or energized. The parts of the relay are arranged to permit armature 59 of winding 58 to operate into or from its deenergized and energizedpositions without effecting operation of armature 55 of winding 35, when the latter armature is in its normal position.

Lever El of Fig. 2 in its normal position N connects terminal B with wire l5 and terminal C with wire l6, and in its reverse position, con nects terminal B with wire l6 and terminal C with wire l5.

' Wires l5 and ll; of Fig. 2, although'constantly' connected by lever El to the source of current are normally deenergized by virtue of the fact that the circuit across the wires normally is open,

through contact 38 l2 of lever El, wire l6, normal'polar contact 525fi of relay PR, normal polar contact Ell-53 of relay PR, and the winding of relayNR to terminal 0. The energization of relayNR closes front contact 28-439 to energize winding 18 of relay PR, and front contact 26-27 of relay NR also becomes closed tocomplete a circuit which includes winding 58 of relay OR! in series with the winding of magnet RM, thereby energizing reset winding 58 of relay ORI (which causes contact Gi-lila to close) and reset magnet RM (which causes contact l2'l2a to close). In addition, contact 52-53 of relay NR is closed by contact finger 25c of relay NR to complete a circuit for windings lla--l'lb of relay PR, which circuit extends from wire [6 through windings lid-I'll) of relay PR, contact E2Hia of reset magnet RM, contact 5la6l of winding 58 of relay ORl, and contact 53- -62 of relay NR to wire l5. The polarity of energization of windings l'la -l'lh oi? relay PR is such that the relay operates its armature to its reverse position, thereby opening its normal con tacts 525il and 5l56 to interrupt the previously traced circuit of relay NRso that relay NR releases. With relay NR released, winding 58 of relay ORl, reset winding RM, winding l8 of relay PR and windings i'lolllb of relay PR "all become deenergized. Also, when back confor relay PR across the two control wires l5 and l6. i

To restore relay PR and switch S to-their respective normal positions, lever B l is moved to its normal position, thereby energizing relay NR over a circuit extending from'terrninal B through contact 38 lt of lever El, wire l5, reverse polar contact 55-5l of relay PR, reverse polar contact 52--54 of relay PR. and the winding of relay NR ing 58 of relay ORE, reset magnet R'i/l, winding ll! of relay PR and magnet ll of relay PR are all energizedjand the polarity of energization of magnet l! is now such that armature of relay PR is swung to its normal position, thereby open ing its reverse polar contacts 55-5l and 59-54 to interrupt the circuit of relay NR. When relay NRreleases and closes back contact fill-3i normal switch operating relay N'WR becomes energized to control the switch S to its normal position.

It should 'benoted that whenever lever'El is moved to a position out of correspondence with polar relay PR, the movement of lever El to such position closesa circuit across wires 55 and l B which energizes relay NR. Relay NR, accordingly, is energized only whenever lever El is moved to a position out of agreement with relay PR.

In the event that switch S is manually operated to a position out of correspondence with switch control relay PR and the selector is restored to its normal position,.circuit controlling contact 8 9 is held in its open position by virtue of the toggle biased contact controlling member l. Thus, when'selector SL is restored to its normal position, circuit controlling contact t-9 being open prevents either relay NWR or RWR'from to terminal C. With relay NR energized, windbeing energized, and thereby avoids automatic restoration of the switch to its position of correspondence with relay PR after a manual operation of the switch.

In the event that circuit controlling contact 89 is held open by the toggle biased contact controlling member I, the contact is restored to its normal position to thereby establish remote control of switch S whenever lever El is operated to its position out of correspondence with relay PR and relay NR becomes energized. Under the above conditions, the energization of relay NR causes reset magnet RM to become energized and actuate its armature ll into its attracted position to operate contact controlling member 1 against the action of toggle l9 into its normal position. Circuit controlling contact 8-9 now becomes closed. Thus, for example, if switch S is manually operated to its position out of correspondence with lever El and relay PR, contact 89 becomes closed only when lever E! is moved to its position of correspondence with switch S and causes relay PR to assume its position of correspondence with switch S. In the event that the switch is manually operated and is left at its position of correspondence with lever El and relay PR when selector SL is restored to its normal position, the operation of lever El to its position out of correspondence with relay PR causes contact 8-9 to become closed, and also causes relay PR and switch S to be operated to their respective positions of correspondence with lever El. It follows from the foregoing that remote control of the switch is established only when circuit controlling contact 3-43 is caused to become closed when the switch. control lever is moved to a position out of correspondence with the polarized switch control relay.

It should be pointed out that whenever lever El is moved to a position. out of correspondence with relay PR during the interval that selector SL conditions the switch for manual operation, contact 8-4) is held open by selector SL against the energization of reset magnet RM to prohibit remote control at this time. Also, since contact l2.l2a of reset magnet RM is held open under the above conditions, relay PR is not operated to its position of correspondence with lever El, but remains at its position out of correspondence with lever El until such time selector SL is restored to its normal position. Then, however, when selector SL is restored to its normal position, contact l2--l2a of reset magnet RM closes and relay PR operates to its position of correspondence with lever El. If, now. switch S is in correspondence with lever El, no operation of the switch is effected, but the switch is out of correspondence with lever El, then relay PR controls the switch operating relays NWR and RWR to cause the operation of switch S to its position of correspondence with lever El.

In the event that overload relay OR! operates its main armature 56 to its operated position due to current of overload ma nitude being drawn by motor M. it can be seen that armature 55 is restored to its normal position whenever lever El is moved to its position out of correspondence with relay PR to cause the energization of relay NR and consequent energization of reset magnet 58 of relay ORl.

An advantage of the apparatus of Fig. 2 is that automatic restoration of the switch to its position of correspondence with its polarized switch control relay is avoided by means of a circuit controlling contact 8-9, which is so constructed and controlled as to require the xninimum of apparatus to provide the above protection in switch control systems for a dual-control switch mechanism.

Although I have herein shown and described only two forms of improved switch control srs' terns embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. The combination with a railway track switch having a two-position selector effective in but one position to condition the switch for power operation, oi a circuit controlling contact operativcly associated with the selector and operated from a normally closed position to an open position when the selector is moved out of its said one position, said contact having means for maintaining the contact in its open position when said selector is restored to its said one position, a switch. control lever having normal and reverse extreme positions, power operating means, means controlled by said lever when operated to an extreme position and including said circuit controlling contact in its closed position for controlling said power operating means to move the switch to a position of correspondence with said lever, and means controlled by said lever and effective when and only when said selector is in its said one position for restoring said circuit controlling contact to its normal position upon movement of said lever.

2. The combination with a railway track switch having a two-position selector effective in but one position to condition the switch for power operation, of a circuit controlling contact operatively associated with the selector and operated from a normally closed position to an open position when the selector is moved out of its said one position, said contact having means for maintaining the contact in its open position when said selector is restored to its said one position, a switch control lever having normal and reverse extreme positions, a polarized switch control relay, circuit means controlled by said lever and effective when and only when said selector is in its said one position for operating said relay to a position of correspondence with the extreme position of said lever, power operating means, means controlled by said relay and including said circuit controlling contact in its closed position for controlling said power operating means to operate the switch to a position of correspondence with said relay, and means controlled by said lever and efiective when and only when said selector is in its said one position for restoring said circuit controlling contact to its normally closed position upon movement of said lever.

3. The combination with a railway track switch having a two-position selector effective in but one position to condition the switch for power operation, of a circuit controlling contact operatively associated with the selector and operated from a normally closed position to an open position when the selector is moved out of its said one position, said contact having means for maintaining the contact in its open position when said selector is restored to its said one position, a switch control lever having normal and reverse extreme positions and biased to an open intermediate position, a polarized switch control relay, circuit means effective when and only when onenesssaidzselector" is in its said' one. position for con:-

' trolling saidrrelay to a position otfcorrespondor operating means; circuit meanscontrolled by once with the extreme position'of said lever, powsaid switch control relay and including'said circuit controlilng. contact :in' its closed position forcontrolling said poweroperating means'to operate the switchto its position of correspondencenormal position upon operation of said lever to either of its extreme positions. a

4. The combination. witharailway trackswitch having a two-position. selector efiective in but one position to condition the switch for power" operation, of a circuit controlling contact operatively associated with theselector and operated from a normally closed position toan open position when the selector is moved out of itssaid one position, said contact having means for maintaining the contact in its open position whensaid selector is restoredto its said one position, a

switch control lever havingnormal and reverse extreme positions and biased to an intermediate position, two normally deenergized control line circuit controlling contact in its normally closed position for controlling said'power operating means to operate the switch to a position of 'cor- I I respondence with said relay, and. means controlled by saidlever and efi'ective'when and only when said selector is in its said one position for restoring said circuit controlling contact to its normally'closed position upon operation of said lever to either extreme'p'osition;

5. The combination with a railway track switch having atwo positi'on selector efiective in but one position to condition the switch for power operation, of a circuit controlling contact opera tively associated with the selector and operated 1 from a normally closed position to an open position when the selector is moved out of its said one position, said contact having means for maintaining the contact in its open position when said selector is restored to its said one position, a

switch control lever having normal and reverse position, two normally deenerglzed control line' extreme positions and biased to an intermediate wires, a source of current connected by said lever to said control wires to supply current of normal or reverse polarity to such wires according as said lever is in its respective normal or reverse extreme position, power operating means for operating said switch. control. means selectively controlled in accordance with the polarity of energization of said control wires for controlling the operation of said power operating means to cause said switch to be moved to a position of correspondence with said lever, means controlled by said circuit controlling contact when held opened by said selector being out of its said one position for preventing said control means from responding to the said selector is. iniits said'one position for re-.

polarity is supplied to said control wires; when.

storing said circuit controlling-contact to its normally closed position.

6; The combination with a railway track switch having a two-position selector effective in but tion when the selectoris moved out of its said.

one position, said contact having means for maintaining the contact in its open position when said selector is restored. to its said one position,. a

switch control lever having normal and reverseextreme'positions. and biased to an'intermediate position, two normally deenergized control line wires, a source of current connected by said lever tozsaid. control wires to. supply current of normal or reverse; polarity to such wires. according as said lever is in its respective normal or reverse extreme: position, a neutral relay connectedin circuit'with said controlwires, a polarized switch control relay mechanically interlocked with said neutral relay whereby saidpolarized relay is permitted to reverse its polar contacts only when said neutral relay isenergized, means effective when said neutral relay is energizedfor connectingsai'dipolarized relay in circuit with said control. wiresprovided that said selector is in its said one position, power operating means .for operating. theswitch,.means controlled by said'polarized relay and including said circuit controlling con.- tactinitsnormally closed position for controllingsaid. poweroperating means tooperate the switch to a position of correspondence with said polarized. relay, and means controlled by said neutral relay when energizedfand effective when and 'only'whenxsaid selector is in its said onepositionfo-r restoring: said circuit controlling contact to its. normally closed: position. v

. 7.. The combinationwith a railway track switch h'avinga two-position:- selector' effective in but oneposition to condition the switch for power operation,v ofa circuit controllingcontact opera tively associated with .the selector and operated from. a-normally closed position to an open position when the selector is moved out of its said one position, said contact having means for maintaining the contact in its open position when said selector is restored to its said one position, a switch control lever, a polarized switch control relay, means controlled by said lever and efiec- 'tive when and only when said selector is. in its to operate the switch. to-a position of correspond-' ence with said relay, and means controlled by said. switch control lever and effective when and only when said selector is in its said one position and said lever is out of correspondence with said relay for restoring said circuit controlling contact to its normal position.

8. The combination with a railway track switch.

having a two-position selector effective in but one position to condition the switch for power operation, of a circuit controlling contact operatively associated with the selector and operated from a normally closed position to an open position when the selector is moved out of its said one position, said contact having means for maintaining the contact in its open position when said selector; is restored to its said one position, a switch control lever having normal and reverse positions, a polarized switch control relay, circuit means controlled by said lever and effective when and only when said selector is in its said one position for operating said relay to a position of correspondence with said lever, power operating means for operating the switch, means controlled by said relay and including said circuit controlling contact in its normally closed position for controlling said power operating means to operate the switch to a position of correspondence with said relay, and electromagnetic means controlled by said lever when and only when said lever is out of correspondence with said relay and said selector is in its said one position for restoring said circuit controlling contact to its normally closed position.

9. The combination with a railway track switch having a two-position selector effective in but one position to condition the switch for power operation, of a circuit controlling contact operatively associated with the selector and operated from a normally closed position to an open position when the selector is moved out of its said one position, said contact having means for maintaining the contact in its open position when said selector is restored to its said one position, a switch control lever having normal and reverse positions, a neutral relay, a polarized relay mechanically interlocked with said neutral relay in such manner that said polarized relay can operate its polar contacts only when said neutral relay is energized, means controlled by said lever for energizing said neutral relay when and only when said lever is out of correspondence with said polarized relay, means also controlled by said lever and effective when said neutral relay is energized provided that said selector is in its said one position for causing said polarized relay to operate to a position of correspondence with said lever, power operating means for operating said switch, means controlled by said polarized relay and including said circuit controlling contact in its normally closed position for controlling said power operating means to operate said switch to a position of correspondence with said polarized relay, and means controlled by said neutral relay and effective when and only when said selector is in its said one position for restoring said circuit controlling contact to its normally closed position.

10. The combination with a railway track switch having a two-position selector eiiective in but one position to condition the switch for power operation, of a circuit controlling contact operatively associated with the selector and operated from a normally closed position to an open position when the selector is moved out of its said one position, said contact having means for maintaining the contact in its open position when said selector is restored to its said one position, a switch control lever having normal and reverse positions, a neutral relay, a polarized relay mechanically interlocked with said neutral relay in such manner that said polarized relay can operate its polar contacts only when said neutral relay is energized, means controlled by said lever for energizing said neutral relay when and only when said lever is out of correspondence with said polarized relay, other means also controlled by said lever and effective when said neutral relay is energized for causing said polarized relay to operate to a position of correspondence with said lever, means controlled by said selector lever in the other of its two positions and interposed in said other means for preventing operation of said polarized relay when said selector is in its said other position, power operating means for operating said switch, means controlled by said polarized relay and including said circuit controlling contact in its normally closed position for controlling said power operating means to operate said switch to a position of correspondence with said polarized relay, and means controlled by said neutral relay and efiective when and only when saidselector is in its said one position for restoring said circuit controlling contact to its normally closed position.

CLARENCE W. DALZELL.

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