US1824151A - Interlocking system for railroads - Google Patents

Description

M M E Sept. 22, 1931. w. K. HOWE INTERLOCKING SYSTEM FOR RAILROADS 4 llllllll Ill o I! lI/t lllllll e mm M n a Q m EH 5 0m O o ,been accomplished by Patented Sept. 22, 1931 UNITED STATES PATENT Fries WINTHRO]? K. HOWE, OF ROCHESTER, NEW YCRK, ASSZGNO R TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK INTERLOGKING SYSTEM FOR RAILROADS Application filed November 14, 1929.

This invention relates to interlocking systems for railroads, and more particularly pertains to indication means and devices for use in such interlocking systems.

Where a number of track switches are controlled by their respective control levers located in a central tower, it is desirable to provide means indicating in the tower the position and locked condition of the associated track switches, so that the governing control levers may be allowedto be operated to full normal or full reverse positions only when the associated switch machines are in corresponding normal, or reverse positions and locked. In one type of system, this has the use of separate line wires comprising a polarized circuit controlled by the track switch for operating a three position SS, or switch repeating, relay in the interlocking tower.

In accordance with the present invention, it is proposed to provide such an SS relay which is controlled over the regular operat ing wires of the switch machine by the use oi super-imposed alternating current. More specifically, it is proposed to employ the two field windings, of a double field winding type electric motor, alternately as the primary and secondary windings of a transforming means for super-'mposing alternating current upon the control wires of said electric motor. further object is to so correlate the indication system with the control systenithat it will be impossible for the control lever to be operated out of correspondence with its switch machine.

Other objects, characteristic features and advantages of the present invention will be in part obvious from the accompanying drawing, and in part pointed out as the description of the invention progresses.

The single figure of the accompanying drawing represents in a diagrammatic manner one embodiment of the present invention as applied to one type of electric interlocking system.

'With reference to the accompanying drawing, one end of a passing siding PS has been shown with a track switch TS connecting it to a stretch of main track MT. The main A i when the track switch operation. The movable contact 6 makes conintermediate position.

Serial No. 40?,133.

track MT, and the portion of the siding out to the fouling point are provided with inture A and two field windings F and F one of which, when energized in series with the armature, operates the switch machine in one direction; and the other of which, when energized in series with the armature,

operates the switch machine in an opposite direction. Included in the switch machine control circuit is a brake BR which normally prevents operation of the switch machine except when a normal value of operating current is flowing in its windings to actuate it .to a released condition. Associated with the rack switch TS and switch machine SM are movable contacts 6, 7 and 8 which assume extreme normal orreverse positions when the track switch TS is in extreme normal or reverse positions respectively and locked, and which assumeintermediate central positions TS is unlocked or in tact between a pair of fixed contacts when in a normal or interinediate'position, while the movable contact 7 makes contact between a pair of'iixed contacts when in a reverse or The movable contact 8 makes contact between one pair of fixed contacts when in a normal position and another pair of fixed contacts when in a reverse position. 1

A transformer T has its primary connected to a suitable alternating current source of potential provided bya transmission line extending from the interlocking tower, and has its secondary provided with a center tap for purposes hereinafter set forth;

. In the interlocking tower, a control lever L is provided for controlling the switch machine SM- over normal and reverse operating wires 9 and 10 respectively. The lever L operates movable contact blocks 11, 12 and 13 to which it is connected by a suitable rod. These movable contact blocks 11, 12 and 13 make contact between certain pairs of fixed contacts when the control lever L is in normal or half normal positions N and HN respectively, and make contact between certain other standpoint of operation.

tions of a protective relay and low reslstance ,windlngs pairs of fixed contacts when the control lever L is in reverse or half reverse positions R and HR respectively. The lever Lv is prevented from movement to the full normal or the full reverse position by the usual indication latch mechanism IL which is released by the energization of an indication magnet IM. A safety magnet S is provided which, when energized, prevents the actuation of the indication latch mechanism IL by the indication magnet IM. 1

The lever L is provided with a lever latch 14 which operates an energy saving contact 15, Also, a tappet bar Q0 is operated by a cam slot in the lever L in the usual manner for controlling the mechanical interlocking between the lever L and its associated opposing levers. I

A SS relay is provided with a local winding 16 continuously energized from the secondary of a local transformer T the primary of whichis connected to the same transmission line as the local transformer T at the switch machine. The line phase winding 17 of the SS relay is energized by alternating current supplied from the local transformer T over the operating wires of the switch machine in a manner as hereinafter set forth. 'The contact 18 of'the SS relay is operated to an extreme normal or reverse position depending upon the instantaneous relatlve polarity of the alternating currentin the line phase winding 17, and assumes a. central deenergized non-contacting position when either or both the local and line phase windings are deenergized.

A suitable power supply for the switch machine SM is provided by a battery BT, or any other convenient source of electrical potential. Operating current is supplied to the switch machine SM in accordance with the position of the control lever L, the positions of a track repeating relay H and L respectlvely. The operating current of the switch machine flows through normal and reverse operatlng c01ls of an indication selector IS to insure the correspondence of the lever L with the switch TS.

It is believed that the usefulness of the system and the correlated functions of the various devices will be best understood by further I description being given from the control TR, and the posi- PR having. high Operation of the system The track switch TS is shown in the normal locked position so that traffic may pass in either direction .over the main track MT. Also, the lever L in the interlocking tower is in a full normal position N controlling the tappet bar 20 to release certain conflicting levers by the mechanical interlocking between levers in the usual well known manner.

Assuming that a contact 21 of the indication selector IS is operated to a normal position by the last operation of the switch machine, the normal energizing current for the line phase windings 17 of the SS relay is completed,.so that it receives energy from the transformer T This normal energizing circuit for the SS relay is effective because the transformer T energizes the field winding F which causes the field winding F to act as the secondary of a transformer in which a current is induced that energizes the line phase winding 17 of the relay SS over tlfie next operating circuit of the switch mac me.

circuit traced as follows :from the center tap of the secondary of transformer T through wires 25 and 26, field winding F wire 27, contacts 8-28, wire 29, to the right-handwires 30, and 31, armature A, wire 32, wind- .lng of brake BR, common wire C, wire 33,

back contact 34 of phase winding 37, contacts 1238, reverse operating wire 10, contacts 639, wire 40, to the left-hand terminal of field winding F With the line phase winding 17 of the relay SS energized over its normal energizing circuit, its instantaneous relative polarity is such in relation with the instantaneous relative polarity of the local phase winding 16, that thecontact 18 assumes a right-hand normal energized position, in which. position the energizing circuit of the indication magnet IM may be completed by actuation of the lever latch 14 to close power saving contact 15.

Assuming the leverlatch 14 to be actuated, the normal energizing circuit for the indication magnet IM is traced as follows :from the positive terminal of a suitable source of electrical potential indicated as B through contact 18 of relay SS in a right-hand normal position, wire 44, contacts 11 45, wire 46, contact 21 of indication selector IS in a rightrelay PR, wire 35, line hand position, wire 47, windings of indication magnet IM, wire 48, contact 15 in a 17 of relay SS, wires 36 and 1 The field winding F 1s energized through a closed position, to the negative terminal of the suitable source indicated as B The operator can control the track switch TS to a reverse eXtreme position by the movement of the lever L 1n a left-hand direction until the half reverse position HR is reached. Further movement is prevented by the indication latch mechanism IL until the indication magnet TM is again actuated. With the control lever L in a half reverse position, the initial reverse oper ting circuit for the switch machine is traced as follows :-from the positive terminal of battery BT, through the fuse F wire 49, front contact 50 of relay TR, wire 51, high resistance windings H of relay PR, wires 52 and 53, low resistance winding L of relay PR, wire 54, windings of safety magnet S, wires 55 and 56, reverse winding 57 of indicationselector IS, wire 62, contacts 13-58, wire 59, reverse operating wire 10, contacts 6-39, wire 40, field winding wires 30 and 31, armature A, wire 32, winding of brake BR, common wire C, to the negative terminal of battery ET. This circuit, however, includes the high resistance winding H of relay PR which prevents sufficient current from flowing in this circuit to operate the switch machine SM and the indication selector IS. However, the energization of the high resistance winding H actuates the contacts of the relay PR to energized positions, one of which is then effective to shunt out the high resistance winding H allowing the operating currenoto reach a value suflicient to operate the contact 21 of the indication selector TS to a left-hand extreme position, suificient to release the brake BR of the switch machine, and sufficient to operate the switch machine SM. This shunt includes wire 60 connected to fuse F front contact 61 of relay PR, the wire 53 and the low resistance winding L. Thus, the contacts of the relay PR are maintained in an actuated position by the energizat-ion of the low resistance winding L although the high resistance winding H is shunted out.

The switch machine SM now unlocks the track switch TS and operates it to a reverse position in which it is again locked.

During the operation of the switch machine SM and as soon as the track switch is unlocked, the movable contacts 6, 7 and 8 are operated to their intermediate positions. With the contacts 6 and 7 in intermediate positions both the reverse and normal energizing circuits are completed at the switch machine, thus the reverse energizing circuit is completed if the lever L is maintained in a reverse position, while the normal energizing circuit will be completed if the lever L is returned to a normal position. With the movable contact 8 in an intermediate position, the energizing circuit for causing the field winding F to act as the primary of a transformer is open at contacts 8-28, thus insuring deenergization of the line phase winding 17 of the relay SS while the track switch is unlocked. It will be pointed out in this connection, that the line phase winding 17 is deenergized as soon as the contact 34 of relay PR is actuated to an energized position even before the switch machine SM receives operating current to unlock the track switch TS. I

As soon as the pletes the operation of the track switch TS to a reverse position and locked condition, the contacts 6, 7 and 8 are operated to their reverse eXtreme positions which causes the reverse operating circuit to be opened at contacts 6-39 and which causes alternating current potential to be placed across the field winding F so that it will operate as the primary of a transformer in a similar manner as the field winding F chine is in a normalposition. A predetermined time after the operating current of the switch machine ceases to flow through the low resistance winding L of the relay PR, the

tions so that the energizing circuit for the l1ne phase winding 17 of relay SS may be completed.

lVith the switch machine SM in a reverse the field winding F is energized position, from the transformer T through a circuit traced as follows z-froin the center tap of the secondary of transformer T through wires 25 and 30, field winding F wire 65, contacts left-hand terminal of 8-66, wire 67, tothe the secondary of transformer T The field winding F now acts as the secondary of a transformer with its induced current flowing through the reverse energizing circuit for the line phase winding 17 of the SS relay, which circuit is traced as follows i-from the righthand terminal of field winding F through wires 26 and 31, armature A, wire 32, winding of brake BR, common wire C, wire 33, back contact 34 of relay PR, wire 35, line phase winding 17 of relay SS, wire 36, contacts 12-68, wires 69 and 9, contacts 7-70, wire 71, to the left-hand terminal of field winding F As the reverse energizing circuit for line phase winding 17 gives a current of reversed instantaneous polarity, the contact 18 is now actuated from a deenergized position to a left-hand reverse position. may actuate the lever latch 14 which closes the contact 15 and thus energizes the indication magnet IM through a circuit traced as follows :-from the positive terminal of a suitable source of electrical potential indiwire 73, contacts 11-74, wire 75, contact 21 of indica ion selector TS in a left-hand reverse position, wire 47 windings of indication magnet IM, wire 48, contact 15 witch machine SM. comwhen the switch ma- The operator.

. 0 contacts 34 and 61 assume deenergized pos1- -5 cated as 13+, through contact 18 in a leftin hand position,

in a closed position, to the negative terminal the movable contacts of of the suitable source indicated as B. The energization of the indication magnet IM releases the indication latch IL which permits the operator to move the lever L further in a left-hand direction to the full reverse position N which operates the tappet bar 20 in the usual manner to release the mechanical interlocking between the lever L and certain conflicting levers.

The operation of the system has been described from the normal condition to' the reverse condition which is deemed sufiicient to point out the characteristic features of the present invention as the operation of the system from a reverse condition to normal con dition is merely an inverse function of the operation already described.

It will be noted that the relay PR allows its contacts 34 and 61 to assume biased deenergized positions a predetermined time after the operating current of the switch machine SM ceases to flow in the low resistance winding L. This releasing time period of the relay PR is of sufiicient value to allow the control lever L to be moved from a half normal position I-IN to the half reverse position HR in mid-operation of the switch machine without the contact 61 opening its'front contact, which maintains the operating circuits intact for quick reversal.

The combination of the high resistance Winding II with the low resistance winding L and the track repeater relay TR allows the switch machine SM to complete its operation should a train enter the detector track section DT shortly after the track switch TS has begun to be operated which, for example, is completely set forth in my pending application Ser. No. 370,906 filed June 14, 1929.

From the above description, it is obvious that the control lever L cannot be moved from a governing position such-as HR and HN to the corresponding full positions R and N, due to the indication latch mechanism IL, except after said mechanism has been actuated b the energization of the indication magnet IM. This indication magnet IM depends for its energization upon the correspondence of the contact 21 of the indication selector IS and thecontrol lever L with the position assumed by the contact 18 of the SS relay. The SS relay in turn depends upon the deenergization of the protective relay PR.

lVith such an arrangement, the control lever L cannot be moved to a new governing position and then returned to the former governing position to receive an indication before the switch machine has operated to unlock the track switch TS, which would be extremely undesirable should a fuse blow at that time allowing the momentum of the switch machine to continue to operate the track switch to an unlocked condition. One method used to accomplish this result and the associated control lever the circumstances in which such undesirable inent invention provides double check against such improper operation by the provision of the protective relay PR and the indication selector IS.

The protective relay PR opens the energizing circuit for the line phase winding of the SS relay before operating current for the switch machine flows and does not again close its back contact until after a predetermined time, which, as well as being sufficient to allow the control lever L to be returned to a former governing position in mid-stroke ithout opening the control circuit, is also of suficient duration to permit the switch machine to come to rest should it have received any operating current when lever L was in the new governing position. If the SS relay then indicates that the switch machine is still in a locked extreme position in correspondence with the former governing position of the control lever L, indication magnet IM could be energized and the control lever L be returned to a former full position. However, the indication selector IS prevents such returning'of the control lever L in a manner as obvious from the above description if the switch machine SM receives sufficient amount of operating current to affect its operation.

However, if therequirements of practice demand that the control lever L be returned to a former full position although it has re-'' ceived operating current but has not unlocked the track switch, the indication selector IS may be omitted without detracting from the present invention, as the protective relay PR is suflicient to meet the other requirements 4 of an interlocking system. The indication selector IS thus provides a double check that the control lever is in correspondence with its switch machine and also an additional function as heretofore mentioned, which is desirable in some cases.

An interlocking system has thus been shown and described which employs the two field windings of an electric motor to act alternately as the primary and secondary respectivelyofa transformer for super-imposingalternating current upon the control wires of the interlocking system to accomplish the indication of the position and locked condition ing tower, in a simple and economical manner, and also in a manner which prevents its to be moved out of correspondence therewitl.

Having described one specific embodiment of the present invention, it is to be understood the various circuits'und devices are used ilitate in the disclosure of the invention rather than to limit the invention to one s )8- l of a track switch in the interlock-' be understood that various modifications, alterations and adaptations may be made to meet the requirements of practice without departing from the spirit and scope of the invention as set forth in the appended claims.

Having described my invention, I now claim 1. In an interlocking system for railroads, a track switch, a power operated switch machine having an electric motor of the double field winding type, a control lever, normal and reverse operating wires governed by said control lever, contacts operated jointly by said track switch and said switch machine for connecting either said normal wire or said reverse wire to its respective one of said field windings to produce rotation in a direction to operate said track switch to an opposite position, means energizing the last used field winding with alternating current, whereby alternating current is induced in the other field winding connected by said contacts to its respective operating wire, and indication means controlled by said induced currents.

2. In an interlocking system for railroads, a track switch, a power operated switch machine having an electric motor of the double field winding type, one field for producing rotation in one direction and the other field for producing rotation in an opposite direction, and means for alternately using said field windings as primaryand secondary windings of a transforming means in accordance with the position of said track switch.

3. In an interlocking system for railroads, a. track switch, a power operated switch machine having an electric motor of the double field winding type, means for alternately energizing one or the other of said field windings with alternating current in accordance with the position of said track switch, whereby alternating current is induced in the opposite field winding, and indication means operated by said induced current with sald indication means indicating the position of said track switch.

4. In an electric motor for railroad signaling purposes, an armature, a field winding having a center tap connected to said armature, operating circuits connected to the extremities of said field winding and to the opposite terminal of said armature, and means energizing one-half of said field winding with alternating current to induce a current for indication purposes in the operating circuit connected to the other half of said field winding.

5. In an interlocking system for railroads, a track switch, a switch machine, a control lever, normal and reverse operating circuits, an indication latch mechanism, means indicating the position and locked condition of said track switch for governing said indication latch mechanism, means connecting said indicating means across said operating circuits, means for super-imposing alternating current upon said operating circuits, and means for disconnecting said indication means from said operating circuits when said switch machine receives operating current.

6. In an interlocking system for railroads of the type substantially as shown and described, a track switch, a switch machine driven by a motor having two field windings, a control lever, operating circuits, indication means, and means including said field windings for super-imposing alternating current on said operating circuits for controlling said indication means.

7. In an interlocking system for railroads, a track switch, a power operated switch machine having an electric motor of the double field winding type, normal and reverse operating wires, contacts operated by said track switch and said switch machine for connecting either said normal wire or saidreverse wire to its respective field winding depend ing upon the position of said track switch, a common wire, means energizing one of said operating wires and said common wire to operate said track switch to one position or the other, a shunt cross protection circuit, indication means included in said shunt cross protection circuit, means opening said shunt cross protection circuit during operation of said switch machine, and means energizing said indication means with alternating current induced in the one of said field windings connected to its operating wire while said switch machine is at rest.

8. In an interlocking system for railroads, a track switch, a power operated switch machine having a double field winding type elec-. tric motor, means for alternately energizing one or the other of said field windings with alternating current of opposite relative polarity respectively in accordance with the position of said track switch, whereby alternating current is induced in the opposite field winding, and indication means responsive to said induced alternating current and responsive to the change of relative polarity of said induced alternating current, with said indication means giving indication of the position and locked condition of said track switch.

9. In an interlocking system for railroads, a track switch, a switch machine having normal and reverse operating circuits, a control lever, an indication latch mechanism, indication means indicating' the position and locked condition of said track switch, said means having control circuits in part including said switch machine operating circuits, means for super-imposing alternating current upon said control. circuits of said indication means, and means actively disconnecting said control circuits of said indication means from said operating circuits when said switch machine receives operating current, said means maintaining its active condition for a predetermined time after said operating current of said switch machine ceases to flow.

10. In an interlocking system for railroads, atrack switch, a power operated switch machine having an electric motor of the double field winding type, normal and reverse operating wires, contacts operated by said track switch and said switch machine connecting either said normal 'or said reverse wire to its respective field winding depending upon the position of said track switch, a common wire, a control lever for energizing one or the other of said operating wires and said common return wire to operate said track switch to one position or another, an indication selector having a contact operated to one position or another in accordance whether operating current flows in said normal or said reverse operating wire, an indication latch mechanism, indication means having an indication circuit in part including said normal or reverse operating wire and said common wire, means energizing said indication means with alternating current of opposite relative instantaneous polarity according to the position of said track switch, means for opening said indication circuit of said indica'lion means during operation of said switch machine, and means for actuating said indication latch mechanism when said control lever and saidindication selector are in correspondence with the indication given .by said indication means.

11. In an interlocking system for railroads; a track switch, a power operated switch machine having a double field winding type electric motor, means for alternately energizing one or the other of said field windings with alternating current of opposite instantaneous relative polarity respec tively in accordance with the position of said track switch, said means including a transformer having a center tap, whereby alternating current is induced in the opposite field winding, and indication means responsive to said induced alternating current and responsive to the change of instantaneous relative polarity of said induced alternating current, said indication means giving indication in accordance therewith of' the position and locked condition of said track switch.

12. In combination, a motor having an armature and field windings, normal and reverse operating circuits for said motor, and means including said field windings for superimposing a current of distinctive character upon said opera-ting circuits.

13. In combination,v a motor having field windings, normaland reverse operating circuits for said motor, indication means, normal and reverse indication circuits for said indication means, sa1d indication circuits including in part said reverse and normal operating circuits respectively, and means ineluding said field windings for inducing a' current of distinctive character in said indication circuits.

14. In combination, erable to normal and electric motor for operating said switch machine, said motor having field windings, operating circuits for said motor, indication means responsive to currents of distinctive character, indication circuits for said indication means, and means including said field windings for energizing said indication cir-. cuits with currents of distinctive character depending upon the position of said switch machine.

15. In combination with a railroad switch machine, an electric motor having field windings, a control lever operable to normal and reverse positions, two control wires each used separately in a circuit with a common return wire for operatingsaid motor in opposite directions each circuit of which is established so long said lever and'said switch machine are out of correspondence, an indicating relay associated with said lever, two indicating circuits for said indicating relay each in eluding a difierent control wire together with said common return wire and completed only when said lever and said switch machine are in correspondence, and means including said field windings for causing a flow of current in saidindication circuits respectively in accordance with the position of said switch machine.

In testimony whereof I afiix my signature.

WVINTHROP K. HOIVE.

a switch machine opreverse positions, an

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