US2500616A - Railway switch lock - Google Patents

Description

March 14, 1950 w. c. M WHIRTER 2,500,515

RAILWAY SWITCH LOCK 5 Sheets-Sheet 1 Fileq Aug. 27, 1946 March 14, 1950 w. c. MSWHIRTER 2,500,616

RAILWAY SWITCH LOCK Filea Aug. 27, 1946 5 Sheets-Sheet 2 I N VEN TOR.

March 14, 1950 w. c. MCWHIRTER 2,500,616

RAILWAY SWITCH LOCK Filed. Aug. 27, 1946 5 Sheets-Sheet 3 HIS ATTORNEY March 14', 1950 w. c. M WHIRTER 2,500,615

RAILWAY SWITCH LOCK Filed Aug. 2'7, 1946 5 Sheets-Shqet 4 Swizz/k Uzbem'z 0 Gonpolkn i I Opemed by l C'mwck IN TOR William 6 .1% [Pff 7 BY Z HS ATTORNEY March M 1950 W. s. MCWHHRTER 5 9 RAILWAY SWITCH LOCK Filea Aug. 27, 1946 5 Sheets-Sheet 5 H73 ATTORNEY Patented Mar. 14, 1950 RAILWAY SWITCH LO CK.

William- G. McWhirter, Wilkinsburg, Pa., assignor to The Union Switch and Signal Company, Swissva1e, Pa., a corporation of Penn-- Sylvania Application August 27, 1946, Serial No. 693,221

3' Claims. 1

My invention relates to railway switch locks, and particularly to railway switch locks of the type having circuit controlling contacts which may be utilized in the control of either or both the lock and signaling circuits associated with the track switch governed: by such a look.

It has been proposed heretofore to provide a railway switch lock' with an manually operable locking plunger which cooperates with a lock rod attached to the points of a railway track switch for locking the points against movement, and which locking plunger is provided with lock means effective atv times to prevent operation of the plunger away from a locking engagement with the lockro'd. In the usual construction the switch lock is provided with one or more contacts which become operated automatically upon an action of a trainman preliminary to an operation of the locking plunger. For example, such contacts may be operated bya push rod actuated by a door which must be opened to give access to the locking plunger, so that upon a trainman opening the 'door of the switch lock, the door-controlled contacts are operated to govern circuits including such contacts. A switch lock of this construction is shown, for example, in a copending application for Letters Patent of the United. States; Serial No. 644,338, now Patent No. 2,437,328; dated March 9, 1948; filed jointly by me and Glen V. Jefferson on January 30, 1946',

for Electric switch locks;v

In order to' assure that proper sequence of operation of contacts will be obtained" automatically, it is sometimes necessary'in railway signaling circuits to utilize preliminarily operated contacts of a switch lock in circuits for the control of signals, etc., thereby effecting such controls immediately upon the occurrence of the preliminary action. Where contacts of a switch lock are of the door-controlled type; operation of the contacts and consequent control of thegoverned circuits are effected automatically by opening the door even though it maybe desirabl'eto postpone or even avoid the necessity of effecting such controls.

It is an object of my invention to provide a railway switch lock arranged so as to obtain proper operation of contacts in a predetermined sequence automatically by a trainman in the course of operation of the locking plunger of the switch lock.

Anotherobject isto obtain preliminary operation of contacts bymeans which requires a positive action of-a trainman and which action constitutes a part of the complete" actionrequired way signaling circuits.

to unlock the switch after access to the lock hasbeen obtained.

Another object is to provide a railway switch lock incorporating contacts operated during a preliminary portion of travel of a locking plunger and having means for maintaining the locking plunger at its preliminarily operated position during the time required to obtain release of the lock means;

Another object is to provide means for holding or latching the operating member of a railway switch lock in a preliminarily operated position wherein contacts are governed but release is not effected of the locking imposed by the device;

The above-mentioned and other important objects and characteristic features of my invention are attained by incorporating into a railway switch look a contact or contacts operated during a preliminary portion of the operation of the handle of the lock to its unlocked position, thereby requiring apositive action of a trainman directed toward obtaining an unlock of the track switch, and means for latching the handle at the preliminarily operated position during the interval required to obtain unlocking of the switch lock.

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 front view of a railway switch lock embodying my invention. Fig. 2 is a vertical sectional view'of' the lock shown in Fig. 1. Fig; 3 is a rear view of the lock shown in Fig. 1, with certain parts removed or broken away in order better to illusthe structure illustrated in Fig; 4. Figs. 6a, 6b

5'; Fig; 7 is'a diagrammatic view illustratingthe use of the lock embodying my invention in railviews, similar reference characters refer to cor"- respondingparts.

Referring to the drawings, my invention is illustrated applied to a railway switch lock of 50" the type shown in the previously mentioned application, Serial No. 644,338; Theswitch lock device comprises a casing It] (see Fig. 1) mounted on the upper end of a support H which is 'se-- cured, as bylag' screws [2 to one or morecros's ties I32 Supported in aguideway [4* provided In each of the several in the lower end of support II is a lock rod l of the usual type adapted to be secured to the points of a railway track switch (not shown). Rod i5 is provided with an Opening or hole it which, when the rod occupies a position corresponding to the normal position of the points of the associated switch, aligns with and is adapted to receive a locking plunger l'l pivotally attached to the lower end of an up-and-down rod #8 enclosed within support H and pivotally attached at its upper end to a crank l9. This crank is secured to an operating shaft 26 journaled in suitable bearings 21 (see Fig. 2) provided in a supporting frame 22 secured to the bottom of housing Iii. front and rear compartments 24 and 25, respectively, and shaft 25 mounted in frame 22 disposed in rear compartment 25 projects through an opening 26 into front compartment 24 and has fastened thereto an operating handle 21 provided with a knob 28.

The front compartment 24 is enclosed by a door 29a hinged at one side of housing It and when closed is arranged to be locked in the usual manner by a padlock (not shown) which can be operated by the trainmans switch key. The rear compartment 25 is similarly enclosed by a hinged door 2% arranged when closed to be locked by a padlock which may be opened only by a maintainers key. The doors 29a and 29?) each swing outwardly to give access to compartments 24 and 25, respectively. As indicated in Fig. 1, door 29a carries a projection 30 on its inner side for cooperating with and actuating a push rod 3! which extends from compartment 2 8 through wall 23 into rear compartment 25 for controlling contacts (not shown) in response to an actuation of the rod. A rod 32 also is shown extending from compartment 24 through wall 23 into compartment 25 to provide an emergency release in a suitable manner, such as that explained in the copending application, Serial No. 644,338.

The operating handle 27 has a normal position N (indicated in Fig. 1), in which the handle rests against a stop 33 provided on wall 23. In this position of the handle, plunger rod ll occupies hole [6 provided in lock rod l5, thereby preventing movement of rod l5 and consequently preventing any movement of the points of the associated track switch. The normal N position of handle 2? therefore corresponds to the locking position of the switch lock. Handle 21 is manually operable to a reverse position R (indicated in Fig. 1) provided an electric lock means hereinafter discussed is energized, and in the reverse position R of handle 27, crank l9 actuated by handle 27 through shaft 20 is operated to a position such that plunger rod I 'l is actuated out of engagement with rod Hi to permit movement of the latter rod and of the points of the associated track switch. The reverse position R of handle 21 therefore corresponds to the unlocked position of the switch locking device, and in this reverse position of handle 2'! a stop 34 provided on wall 23 engages the handle to arrest its movement. The parts of the lock mechanism are so arranged and proportioned that handle 2'! when operated to its reverse position and released, remains in that position against stop 34 until restored to its normal position.

A drum type circuit controller 35 (see Fig. 2) is mounted on shaft 20 for operation by handle 2'3. The controller is provided with a plurality of contact bands 36 which cooperate with pairs of conta fingers 31a and 31b disposedon opposite sides A wall 23 divides housing l0 into i of shaft 28 (see Fig. 3) to form circuit controlling contacts governed by the position of shaft 28 and handle 21. The contact bands 36 are secured at their ends within longitudinal slots provided in the insulating drum of the controller, and it follows that by assembling the bands in the proper positions on the drum and by varying their lengths, the contacts 3la'-3l'b, can be made to complete or interrupt a contact in any desired position of handle 21. Thus controller 35 may be arranged to govern a plurality of circuit controlling contacts, some of which may be com pleted in the normal (N) position of handle 2! and opened when the handle is operated away from that position; others of which may be con pleted only when handle 27 is in or near its reverse (R) position; and still others of which may be completed only when handle 2? is in a position intermediate its normal and reverse positions, as for example when the handle is intermediate the X and Y positions indicated in Fig. l and discussed hereinafter. The contact fingers 31a and 3% are secured by means of terminal posts 38 to insulating terminal boards 39 which in turn are supported on supporting bracket 22.

As previously mentioned, the operation of handle 2'! from its normal N to its reverse R. position can be efiected only when an electric lock means provided for the handle is energized. The electric lock means comprises a locking segment 40 formed integrally with crank l9 and provided with a notched or cutaway portion having a shoulder ll which cooperates with a locking dog 42 secured by a finger 43 (see Fig. 2) to a vertically swinging armature supporting member 64. Member 441 is pivotally supported intermediate its ends by trunnions it journaled in trunnion screws 46a screwed through lugs lla provided on a supporting plate 4'! bolted to the upper end of supporting frame 22, and the member 44 carries an armature 38 which cooperates with pole pieces Q9 formed on the lower ends of cores 50 of an electromagnet L. The cores 5!! are mounted in parallel spaced relation in the supporting plate t? and are connected together at their upper ends by a backstrap 5i. Surrounding the cores are coils 52 which will be connected in circuit so as to create cumulative flux in the cores, and which coils constitute the energizing winding for electromagnet L Armature supporting member at extends rearwardly past its point of pivotal support and has secured thereto a counterweight 53 which counterbalances the weight of the armature and looking dog 42 so as to enable a reasonable degree of energization of electromagnet L to attract the armature to its energized position, and thereby lift dog 42 out of the path of travel of shoulder 4|, as will be pointed out hereinafter. The locking dog 42 is operatively connected by means of a vertical rod 55 (see Figs. 1 and 2) with a pivoted indicator 56 visible through a window 5'; in the partition wall 23 of housing Ill. The indicator may assume any one of a variety of forms, but as shown comprises a pivoted arcuate member 58 positioned behind window 5? to display locked or unlocked aspects according as locking dog 32 is released into the path of travel of shoulder ll, or is swung upwardly out of the path of the shoulder.

The armature supporting member id also is operatively connected by a movable insulating link 6% to movable contact fingers, such as fingers SI and 62, which cooperate with other fixed contact fingers, such as fingers 63 and t l, to form circuit controlling contacts 6|-63 and 62-64. The contact fingers GI, 62, 63 and B4 are secured by terminal posts 65, 66, 61 and 68, respectively, to insulating terminal board 69 mounted on the rear end of supporting plate 41. As shown, the fingers are disposed so as to complete or interrupt a contact according as armature 48 is in its full released, or is in its picked-up position, respectively, but it is to be understood that where desired the fingers of either or both contacts may be reversed so as to be opened or closed according as armature 48 is released or picked up.

Locking dog 42 is maintained against lateral displacement by aslotted. guide member it (see 3) formed. integrally with supporting frame 22, and dog 42 is operable from a released posi' tion in which it is adapted to be in the path of travel. of shoulder 4| of segment 40, to an unlocked position in which it is removed from the path of shoulder 4|. The segment 40 is constructed so that with handle 21 in its normal position and armature 48 released, locking dog 42' rests upon. the notched or cutaway portion of the segment, and dog 42 rides on the notched portion of segment 40 when handle 21 is operated from its normal. position, until shoulder an engages dog 42 in the Y osition indicated in Fig. 1. In this Y position of handle 21, looking plunger H is still effectively engaged by rod l5 so as to prevent movement of that rod, but contacts of controller 35 closed in the normal position of the handle become open, and contacts open in the normal position of the handle become closed when the handle reaches a position, such as X indicated in Fig. I, in its movement to the Y position. At the Y position of handlefl, the engagement of shoulder 4| with dog 42 prevents further movement of the handle until such time as electromagnet L is energized to attract its armature 48 and thereby actuate dog 42 out of the path of shoulder 4|. 'In accordance with my invention, contacts operated by handle 27 in the preliminary movement of the handle to the Y position are utilized in the control of electromagnet L, as will be made clear hereinafter in connection with the description ofFig, '7, and during the appreciable interval of time required for these circuits to effect energization of the electromagnet L, it is necessary so as not to interrupt the established circuit conditions, to

maintain handle 21 in its Y position against the bias to its normal position occasioned by the parts, such as rods l1 andl8, that are supported from crank I9.

The handle 2'! is maintained in its Y position, againstthe bias force urging the handle back to its normal position, by means of a latch or detent means. such as shown in Fig; 4. Referring now to Fig. 4, the latch means is shown in the condition obtaining when handle 2'! is operated to its Y position. The latch means comprise a ball 1| carried in the hollow body of knob 28 of handle 21 and pressed by a spring 13 against a plate 14 enclosing the opening in the knob. The ball 1| cooperates with. and rides on a projection 15, provided on wall 23, in the normal position of handle 21, with the projection 15 proportioned so that when handle 21 is operated to its Y position, ball rides oi the projection as represented in Fig. 4 and engages the end of the projection to latch handle 2'! in that position during the interval required to complete the energizing circuits for electromagnet L. It follows that until locking dog 42 is actuated out of engagement with shoulder 4| of segment 40, handle 21. is latched in its Y position by the means illustrated in Fig. 4 and will remain so latched until the locking is released and dog 42 is positioned to permit movement of handle 21 to its reverse position.

In operating the handle 21 shown in Fig. 4 from the reverse to the normal position, the ballll will be depressed when projection 15 is en-- countered at the Y position, and this may offer some slight resistance to the movement of the handle, but operation of the handle to its full normal position can readily be made without difficulty. Also, if handle 21 is operated from its normal to its Y position wherein ball 1| latches the handleby engagement with the shoulder of projection '35, the handle may be manually re-* stored to its normal position, if desired, by the trainman exerting on the handle sufiicient force to depress spring 13 and thereby force ball H to ride up on projection 15 to permit movement of handle 2i to its normal position.

Fig. 5 illustrates a modified form of the detent means shown in Fig. 4, While Figs. 6a, 6b and 6c are partial views showing different positional arrangements of'the detent means of Fig. 5. The detent means of Fig. 5 provides a directional detent operative to detain handle 27 in its Y' position during. movement of the lever from its normal to its reverse position but ineffective to re strain movement of the lever inan operation from its reverse to its normal position. Referring to Figs 5, 6a, 6b and 6c, the latching device shown comprises a ratchet dog pivotally mounted in rear compartment 25 on a pin 8| journaled in lugs provided on the rear face of wall 23, the axis of pin 8i being parallel to the wall so that dog 8% projects at right angles through an open-' ing 82 in the wall. As shown in Fig. 6a, in the normal position of dog 89 it rests on the lower edge of opening 82 with the lower side of the dog projecting slightly into the path of a springpressed rod 83 mounted in the hollow knob 28'. The knob 28 carries a pin 84 which operates in a slot 85 provided in rod 83 to restrict movement of the rod within given limits, while spring 86 is disposed in knob 28 between rod 83 and the closed end of the knob to urge rod 33 to its fully extended position wherein it projects outwardly from the knob so as to ride normally on the outer face of wall 23. The opening 82 is, provided in wall 23 at the Y position of the handle, and the opening is made such that when handle 2'! is operated from its normal to its Y position, rod

83 strikes dog to (see Fig. 6b) to rotate it, about its axis, until dog 80 engages a stop lug 87 which prevents further rotation of dog 80.. The dog 80 when rotated against stop 8'! provides a recessformed by the side of opening 82 and the underside of dog 80 and rod 83: occupies this recess to latch handle 2? against movement toward its normal position. When electromagnet L becomes energized to actuate dog 42 out of engagement with looking segment 4|], further operation of handle 2'! can be made and in this case rod 83 rides on the underside of dog So which as shown is positioned at a slight angle to wall 23. The upper edge of opening 82 is cut away or beveled in such a manner as to permit rotation of dog 8!! into engagement with stop Bl, and when rod 33' clears dog 80 (see Fig. 6c) the dog is returned, either by gravity or by spring pressure, to its normal position in which the upper end of the dog is substantially flush with the outer surface of wall 23. It follows that when handle 2? is operated from its reverse position to its nor-* mal position, the rod 83 rides up the slight angle" provided by dog 80, but the dog is not rotated to provide any recess and as a result operation of the handle is not impeded to any extent other than that necessary to depress rod 83 slightly against its spring 86. It is to be seen that ratchet dog 89 provides a means for obtaining'a recess engageable by rod 83 when operating the handle 21 from its normal to its reverse position, but that on return of the handle from its reverse to its normal position the ratchet forms no recess for engaging rod 83 and no latching action is effected.

The operation of a railway switch lock embodying my invention will be best understood in connection with the apparatus shown in Fig. 7. Referring now to Fig. 7, the reference character W designates a track switch diagrammatically illustrated as provided with a switch lock, of the type embodying my present invention and shown in detail in Figs. 1, 2 and 3. The reference character2l designates the handle of the switch lock, with positions N, X, Y and R of the handle corresponding to the similarly designated positions of handle 27 shown in Fig.1; the reference character L designates the electromagnet of the switch lock; contacts 6|, B2, 63 and 69 correspond to the similarly designated contacts shown in Fig. 3, while the reference characters 99 and 9! indicate contacts controlled by drum controller 35, arranged as indicated in Fig. '7 so that contact 90 is closed or completed in the normal (N) position of handle 2'1, and contact 9! is closed when handle 2'3 is in or intermediate its X and Y positions indicated in Fig. 7. The reference character TER designates a time element relay having a front contact 92 closed only at the end of a predetermined length of time after the operating element 93 of the relay is supplied with energy, and with a back checking contact 94 closed only when the relay restores to its normally deenerg'ized condition and is prepared for another timing operation; the reference character TESR designates a stick relay repeating relay TER; the reference character NWPR designates a normal switch repeater relay provided to repeat the position of the associated track switch W; and the reference characters 95 and 96 designate circuit controller elements operated by the circuit controller (not shown) provided for track switch W. Contacts 95 and 95 occupy the positions shown when switch W is in its normal position, and are operated to the dotted positions indicated in Fig. 7 when switch W is reversed. The reference characters 13 and C designate the opposite terminals of a suitable source of current, such as a battery not shown.

The switch lock usually is provided with means, such as a projection on the inner face of door 29a, which insures that door 29a can be closed and padlocked only when handle 2'1 occupies its normal position. The handle can be operated to its normal position only in the event that plunger rod l1 engages opening it in rod I5, and this is effected only when switch rod occupies a position corresponding to the normal position of switch W. In the normal position of the switch lock, therefore, switch W is locked against movement, handle 2': is in its normal position, and both doors 29a and 2% are closed (as indicated in Fig. 2) and locked by their respective padlocks previousl mentioned. Electromagnet L is deenergized; relays TER and TESR of Fig. '7 are likewise deenergized; and relay NWPR is normally energ'zed over a circuit extending from terminal B through back checking contact 94 of relay TER, back contact 98 of relay TESR, contact 90 of handle 2? closed in the normal (N). position of that handle, contact 6l63 controlled by the are mature of electromagnet L of the switch lock, contact 95 closed in the normal position of switch W, the winding of relay NWPR, contact 96 closed in the normal position of switch W, and contact B l-62 of electromagnet L to terminal C. Relay NWPR closes its front contacts, such as contact I 00, which may be used in the control of circuits, as indicated in Fig. 7 and as discussed herein after. a

If, with the apparatus in the normal condition just described, it is desired to unlock switch W to enable the switch to be reversed, the padlock controlling door 29a must first be unlocked and removed by the trainman, and door 29a then opened to give access to handle 21. This opera-. tion may result in the control of door operated contacts actuated by push rod 3 I, and these contacts may be utilized for an desired purpose not pertinent to the present invention. However, the opening of door 29a does not result in any control of the electromagnet L or of any of the apparatus shown in Fig. '7, with the result that door 29a can be held open as long as desired, and may even be closed, without effecting any change in the condition of the switch lock and associated apparatus other than possible operation of the door operated contacts.

After access to handle 2'! is gained by the trainman opening door 29a, the trainman can then obtain control of switch W by grasping handle 2! and moving it toward its reverse position R. When handle 21 leaves its normal position N, contact 99 is opened to interrupt at that point the previously traced circuit of relay NWPR, and that relay accordingly releases to close its back contact llll to prepare a circuit for winding 93 of may TER, which circuit may be traced from terminal B through back contact 192 of relay TESR, the operating element 93 of relay TER, back contact 19! of relay NWPR, and contact 9| of handle 21, closed in or intermediate the X and Y positions of that handle, to terminal 0. At the X position of handle 21, contact!!! closes so that relay 'IER becomes energized over the circuit previously traced, while continued operation of handle 27, to itsY position results in dog 42 engaging shoulder 4! of segment 49 to prevent further movement of the handle. In this Y position, the previously described latching means for the handle becomes effective to maintain the handle in its Y position against the bias of its parts, and the handle may then be released by the operator until the electric unlock is obtained as indicated by indicator 58 visible through window 51 provided in wall- 23. The unlock is obtained only after a complete cycle of operation of relay TER, that is. only after front contact 92 closes, and then back contact 94 subsequently closes. Front contact 92 of relay TER closes at the end of a predetermined time interval following the completion of the circuit for operating element 93 of the relay, and completes a circuit from terminal B through front contact 92 of relay TER, the winding of relay TESR, back contact Ifll of relay NWPS, and

contact 9! of handle 27 to terminal 0; whereuponrelay TESR, picks up to close its front contact I02 and complete for itself an obvious stick circuit in which contact I02 is connected around front contact 92 of relay TER. The opening of back contact m2 of relay TESR interrupts the previouslytraced circuit of rela 'I'ER at that point, and relay TER. becomes deenergized and closes itsba'ckchecking contact 96 at the end of a predetermined time interval following the deenergiz-ation of element 9?. When back checking contact 94 of relay TER. closes, electromagnet L becomes energized over a circuit from terminal B through back checking contact lid of rela TER, front contact Q8 of relay TESR, and the winding (coils 52 of Fig. 2) of electromagnet L to terminal C. Electromagnet L thereupon attracts its armature 53 (see Fig. 2) to actuate indicator so to cause it to indicate the unlocked condition of the electric lock, and opens contacts 6 9-63 and 62S in the manner previously explained. Armature 8 also actuates locking dog 42 out of the path of movement of shoulder st of locking segment 46, as explained previously, thereby freeing handle 2'! for further movement to its reverse po ition. This operation of handle 2'! to its reverse position usually will be effected immediately by the trainman as soon as indicator indicates un ocked, and in the reverse position of handle 2'5, plunger rod ll is operated out of engagement with rod 55 so that the points of switch W are relea ed and the sw tch is unlocked s that it ma be re e ed.

From the the foregoing description it will be noted that the latching means provided for handle 2! is effective to retain the handle in its Y position during the time required for relay TER to complete the cycle of closing its front contact 92 and subsequently closing its back contact 94. This cycle of operation of relay TER. is initiated by operating handle 2? from its normal (N) position into its Y position, and as is customary in switch locking circuits of this type, the time of operation of relay TER may be used to provide a period of warning to traiiic approaching on either side of the switch, during which period the switch is locked against operation so as to prevent any possibility of causing a hazardous condition of the switch with reference to a proaching traffic. In the system shown in Fig. '7, the contacts operated by relay N'WPR may be used to control the warning of the traffic a roaching the location of switch W. Relay NWPR, as previously explained, is released upon movement of handle 2'! from its normal position and it follows that the warning of traffic is provided automatically by a preliminary operation required of a trainman as a part of the complete operation of handle 2? from its normal to its reverse position, and therefore is initiated only upon a positive act of the trainman indicative of the intention to unlock the track switch. Should the trainman decide not to unlo k the switch after gaining access to handle '2'! by opening door 29a, then in such event door 29a may be closed without in any way interfering with the circuits governing the warning of traffic adjacent to switch W.

The switch lock apparatus may be restored to its normal position, provided the points of switch W are in their normal positions, by operating handle 2i to its normal position, it being noted that in the event handle 21 is provided with latching means of the type illustrated in Fig. 5, n0 latching effect will be imposed by these means at the Y position during operation from the reverse to the normal position. With handle 2! restored to normal wherein plunger rod I; engages rod l5, switch W is locked against operation, while all of the apparatus shown in Fig. '7 will occupy the normal condition as therein illustrated. The door 29a may therefore be closed and padlocked in the customary manner.

An advantage of the apparatus embodying my invention is the provision of means for latching the operating handle of a railway switch look at a preliminarily operated position in which the handle initiates the cycle of operation required to obtain an unlock of the track switch. The latching means obviates the necessity of requiring a trainman to hold'the handle against the bias of the parts in its preliminarily operated position during the period required to obtain release of the switch lock, and the arrangement is such that a specific and positive action of the trainman directed toward obtaining an unlock of the switch is required before the apparatus imposes any change in the signaling circuits government trafiic approaching the position of the Switch.

Although I have herein shown and described only two forms of railway switch locks embodying my invention, it is to be 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:

i. In combination, a casing divided by a partition wall into a front compartment and a rear compartment, a shaft journaled in said partition wall, an operating member in said front compartment operatively connected with said shaft, said operating member having a normal position and an intermediate position and an operated position, means in said rear compartment operatively connected with said shaft adapted to .1 look the points of a track switch against movement in the normal and intermediate positions but not the operated position of said operating member, a locking dog in said rear compartment operable between a locking position and an unlocking position, means in said rear compartment operatively connected with said shaft cooperating with said locking dog to prevent movement of said operating member from its said normal position past its said intermediate position unl ss said locking dog is in its said unlocking position, means in said rear compartment for operating said locking dog into its said unlocking position, a time element device operable from a normal to an operated position at the end of a predetermined time interval, means controlled solely by operation of said operating member for setting into operation said time element device, means controlled by said time element device in its said o erated position, other means governed by said last mentionedmeans for controlling said dog operating means to cause operation of said locking dog to its said unlocking position, whereby said operating member may be freed to unlock the switch points following I the operation of said time element device initiated by operation of said operating member, an element carried by said operating member biased into engagement with said partition wall, an opening provided in said partition wall, a dog pivotally supported to project into said opening and operable upon engagement by said element to rotate to a position in which said dog and said opening provide a recess engageable by said element at said intermediate position of said operating member, whereby to retain said operating member at said intermediate position during the interval required for said time element device to operate to its said operated position.

2. In combination, a casing divided by a partition wall into a front compartment and a rear compartment, a shaft iournaled in said partition wall, an operating member in said front compartment operatively connected with said shaft, said operating member having a normal position and an intermediate position and an operated position, means in said rear compartment operatively connected with said shaft adapted to lock the points, of a track switch against movement in the normal and intermediate positions but not the operated position of said operating member, a locking dog in said rear compartment operable between a locking position and an unlocking position, means in said rear compartment operatively connected with said shaft cooperating with said locking dog to prevent movement of said operating member from its said normal position past its said intermediate position unless said locking dog is in its said unlocking position, means in said rear compartment for operating said locking dog into its said unlocking position, a time element device operable from a normal to an operated position at the end of a predetermined time interval, means controlled solely by operation of said operating member for setting into operation said time element device, means controlled by said time element device in its said operated position, other means governed by said last mentioned means for controlling said dog operating means to cause operation of said locking dogto its said unlocking position, whereby said operating member may be freed to unlock the switch points following the operation of said time element device initiated by operation of said operating member, an element carried by said operating member biased into engagement with said partition wall, and a directional detent for said element comprising an opening provided in said partition Wall, a dog pivotally supported on the opposite side of said wall from said element and disposed to project through said opening into the path of said element and rotatable in response to engagement by said element on movement of said operating member from said normal 1 to said operated position but not on movement,

from said operated position to said normal position, said dog upon rotation forming with the walls of said opening a recess engageable by said element at said intermediate position of said operating member whereby to retain that member in said intermediate position.

3. In an electric switch lock, in combination with a casing provided with a partition wall supporting a shaft provided with an operating member having a normal position andan operated position and an intermediate position, an element carried by said operating member biased into engagement with said partition wall, and a directional detent for said element comprising an opening provided in said partition wall, a dog pivotally supported on the opposite side of said wall from said element and disposed to project through said opening into the path of said element and rotatable in response to engagement by said element on movement of said operating member from said normal to said operated position but not on movement from said operated position to said normal position, said dog upon rotation forming With the walls of said opening a recess engageable by said element at said intermediate position of said operating member whereby to latch that member in said intermediate position to prevent return to said normal position.

WILLIAM C. McWI-IIRTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 681,167 Fairbrother et a1. Aug. 20, 1901 832,166 Salmon et a1 Oct. 2, 1906 1,087,170 Loguin Feb. 17, 1914 1,126,834 Neubert et a1 Feb. 2, 1915 1,535,923 Leake Apr. 28, 1925 1,710,668 Stephenson Apr. 23, 1929 2,193,906 Logan Mar. 19, 1940 2,365,344 Judge Dec. 19, 1944

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