US2416986A - Electromanual railroad switch lock and signal circuit control with emergency release - Google Patents

Description

March 4, 1947. Q 5, HELD AL 2,416,986

ELECTRO-MANUAL RAILROAD SWITCH LOCK AND SIGNAL CIRCUIT CONTROL WITH EMERGENCY RELEASE Filed Sept. 4, 1944 3 Sheets-Sheet 1 3nnentors 0.5.Field and RW. Hewes +heir Gltomeg March 4, 1947. o. s. FIELD ET AL 2,416,986

ELECTRO-MANUAL RAILROAD SWITCH LOCK AND SIGNAL CIRCUIT CONTROL WITH EMERGENCY RELEASE Filed Sept. 4, 1944 3 Sheets-Sheet 2 Y Zhmcntors osmw d RW. Hewes o. s. FIELD ETAL March 4, 1947. 2,416,986 ELECTRO-MANUAL RAILROAD SWITCH LOCK AND SIGNAL CIRCUIT CONTROL WITH EMERGENCY RELEASE Filed Sept. 4, 1944' 3 Sheets-Sheet 3 0.5.Field and Rims;

Patented Mar. 4, i947 ELECTROMANUAL RAILROAD SWITCH LOCK AND SIGNAL CIRCUIT CONTROL WITH EMERGENCY RELEASE Oscar S. Field and Ralph W. Hewes, Rochester,

N. Y., assignors to General Railway Si nal Company, Rochester, N. Y.

Application September 4, 1944, Serial No. 552,637

Claims. (Cl. 246-146) This invention relates in general to a lock device, and has more particular reference to an is usual to provide what is commonly known as an electric switch lock which can be governed both by automatic traffic controlled means and by suitable cooperation between the trainman at the switch and the central operator over suitable communication system. It will of course be appreciated that such electric locks are located on the ties supporting the track rails and thus are subject to extreme vibration and shocks.

With the above noted consideration in mind,

one object of the present invention is to provide an eiiiicient, rugged and practical switch lock adapted to accomplish the various functions and purposes'required of electric switch locks in a modern centralized traific control system.

Another object of the present invention is to provide an electric switch lock which is so constructed as to be immune to shocks and vibrations insofar as its false or unintended release of the lock is concerned.

Other objects, purposesand characteristic features of the present invention will bein part obvious from the accompanying drawings, and in part pointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to the accompanying drawings, in which like reference characters will be used to designate the corresponding parts throughout the several views, and in which- Fig. 1 shows a typical switch layout having a hand-operated switch stand with an electric switch lock constructed in accordance with the present invention applied thereto;

. Fig. 2 is a side view of the electric switch lock with certain parts shown in section as indicated by the section line 2--2 of Fig. 1;

Fig. 3 is a top view of the electricswitch lock with the cover removed so as to show certain parts of the mechanism and contact structure;

Fig. 4 is a sectional end elevation of the electric switch lock taken on line 44 of Fig. 5;

Fig. 5 is a sectional side elevation of the electric switch lock taken on line 55 of Fig. 3; and

Fig. 6 is an organizational view of the proposed electric switch lock with the related parts shown in distorted positions in order to more clearly illustrate their operative functions, rather than to disclose the specific structure.

Referring more particularly to Fig. 1 of the drawings, an electric switch lock EL, constructed in accordance with the present invention, is indicated as associated with. a hand-throw switch mechanism HT which is connected to the movable points of a track switch W. The movable points of the track switch'W areinterconnected by a' front rod 6 which has a throw bar 1 connecting it to a crank arm 8 of the hand-throw mechanism I-IT. The crank arm 8 is operated through a limited are by the hand-throw bar 9 when it is unlocked so that it can be moved from a normal position to a reverse position or from a reverse position to a normal position. Such a hand-throw mechanism HT may be of any suitable type and will thus not be described in further detail. Fig. 6 shows a diagrammatic illustration of the functional operation of such a hand-throw mechanism HT.

As viewed in Figs. 1 and 4, it will be seen that the hand-throw bar 9 is held in a normal position by the electric switch lock by reason of a locking latch In which has an extending foot pedal por-. tion II. This latch I0 is pivoted on a shaft I2 (see Fig. 3).

Referring to Figs. 2, 4 and 6, it can be seen that the latch I0 is normally in a position to hold the hand-throw bar 9 in its normal position, and the latch 10 is held in such position by a detent 13, which detent is pivoted at l4 and has a. hole at its other end which registers with a hole in a lug 15 so that the shackle of padlock P can be inserted. This looks the latch l0 and its releasing control to prevent unauthorized were to be employed to lock the hand-throw bar 9 in its reverse position, it should be understood that the opposite pivot point l9 would be employed. Also, the hold-open bar 26 rests on an inclined portion M of the latch base member 21, but if the lock mechanism were to be employed to lock the hand-throw bar 9 in its reverse position, as above mentioned, then the hold-open bar 2|] would enter its receiving space from the right (as viewed in Fig. 2) and rest on the opposite inclined surface 22 of the latch base member.

The electriclock.Ehcomprisesran outer casing 25 having ahinged'cover 26 with arsuitablehasp and padlock 55 (see Figs. 2- and Within the outer casing 25 is located the electromagnetic.

locking organization. As viewed in Fig. 4, the pedal-latch base 2"! is attached to-t'he side of the lock casing 25, and is held 'i'n'position'by suitable bolts as seen in Fig. 3. The pedal-latch base 2'! has a recessed portion adjacent the lock casing 25 for receiving the hand-throw bar9,'while the inner portion of the pedal-latch base 21 provides an enclosed housing for the tappet -bar 46 and lock rod 50 connecting with'the inner portion of the lock casing 25. The lock casing-'25 is-also supplied with a suitable opening near its base for-allowing the connection of conduit for bringing in lead 'wireszto the contacts-and electromagnetlof thelock mechanism., V j

.: .LReferringLtOiFig. 5,.it willlbeseenthataninner case structure 28 of suitableinsulating material provides .a mounting forpthexterminal posts 29. 'electromagnetcore. 3B, and various of ,the .oper ating means as will upresently be described. :The lower portion of. this inner; structure 28 .has a base.=3l connected to the outer ceasing. 25., while theupper'portion of this inner struoture 'lii is enclosed by a cover plate 32 which .is spring mounted to :the cover .26.:soas to properly assume .a position to tightly enclose, the inner structurelfi when :the .cover. =26 is :moved to its closed position. In this 'way, .the .:inner structom 28' insulates the contacts and cam operating organization .from the-outer casing to provide protection against frost and moisture-condensation upon changes .in temperature and relative humidity. Also, mounted to the top plate 3Z.is.an indicator lamp 33. which :is provided;in such a position that light from it can .pasS through :a glass closed opening .34 included in the .cover'member 26.

seen in Fig. 3, a-shaft 35 is supportedby theside plates '36 .of the inner structure 28, and this shaft 35 is provided with a raisedeam portion and aslotted portionforreceiving the jfingers of-Lthe release arm t'Las will presently be," described. Thexcam shaft 35 is normally held in the position shown .in Fig.3 against the biasrof a1 coil spring 3'5, .and; when in this .positio'n the contact operating cam 38 is in a recess. on the cam. shaft 35 so as to cause the contacts mounted on arm 3.9 to assume their biased positions. Referring to. Fig. 5, it will be seen than the contactarm 39 is pivoted at 46 and iszbiased by a sprin 46 to close its backcontacts. The cam member. 33 is pivoted to the. wall of the inner structure 28 at and has a roller at its. oppoe site end which rides on the shaft 35, while extendingrfrom the. member 3.8 is an arm 4:3which engages a projection on the arm 39 so that if the cam shaft 352is moved to the left b springs! (as seenin Fig. 3), the :roller on the arm 38 rides up the cam surface of the shaft 35 and causes the contact armflll to bejmoved for compressing the spring H and closing the front contactpoints 82 "connected to .the arm 39. .Thesecontacts connected .to. arm .38 may be conveniently termed latch contacts since, they are: operated as soon as-latch I(lisi'eleasedfromdetent l3. Referring to Fig. l, it willibe'seen that the ped alelatch l I it, acts; :through" an :arm. 45-120 fmove compress spring 31. When the padlock detent l3 isremoved so as to release the pedal-latch l l-l 0, then the pedal-latch assumes a position where .-the arm 59 comes in contact with the lock rod '50 due to the weight of the pedal portion I I and the bias of spring 3?. In other words, such release of the pedal-latch allows a certain free movement thereof so that the spring 3? can cause the cam shaft 35 to be moved to a left-hand position in which the contact arm 39 is caused to assume a front contact making position.

Since the lock rod .50 is biased .to the left by a relatively strong spring 5|, the lock rod 58 holds the pedal-latch against further movement, and does not allow the lock-rod 50 to engage the balanced locking stop memberl52. It can be seen in Fig. .4. that the .lowerportion of the casing has two upwardly extending bossesibetween which the locking sto :member .52 is located. and'upon which it is balanced on a pivot shaft 53, so that it may be rotated into a position to in part close the guiding holes for the lock. rod 50 and thus pre- .ventits manual movementagainst the bias spring 5!. More specifically, .it can be seen in Fig. 5 that the locking stop memher52 assumesa position to partially close the holes 54 'andin such position .thelock rod 5iliif forced to .the right (as seenin Fig. 4) by reason of pressure'applied on the pedal portion H, the 'stop member 52 would'be pushed against'the upstanding boss of the base 25. In other words, the locking of the lock rod 50 is effected by dissipating any applied force against the relatively strong upstanding boss of the casing 25.

When the cam "shaftis in a normal position as shown, an extending arm 66 pivoted on the side plate. of the inner structure 28 at El has a roller at its left-hand end engaging the cam shaft 35 so as to be moved downwardly and force a plunger downwardly against the spring .63, and thereby force .or "insure that. the locking stop member 52 is in .a position to prevent longitudinal. movement of the lockrod to a releasing position '(i. e., where latch [0 allows movement of bar 3). It .can be seeniinrFig. 5 that the plunger 62 is provided with suitable guide members attached'to .the bottom plate 3.l "ofthe inner structure andzserving as a support for :the spring 63. At theupper end of the :plunger 62 is an enlarged portion against which the pivoting cam arm cantrest asv seen in'Figs. 4 and 5. 'Also, the arm lit-has a set screw adjusted lower portion to vary thezextent :of its effect .onlplunger 2.

.Whenthe camshaft. 35 assumes its biased position, then the arm 6!] is moved upwardly due to the bias of springBBron the plunger 62, and with the plunger 62. thus raise'dtoJa. position disengfagingthe locking stop "member. 52, it permits its free operation by- :its' associated electromagnetic operating means.

.- Referring to -Fig. '5, it will be seen that 'the inner structure 28 hasmounted at one side the core structure SI] of the ielectnomagnet upon which suitable .coils :are mounted. This core structure 30 has an associated armature structure of non-magnetic material and is provided with a suitable knife-edge bearing .66 and is biased :to a -:deenergized position by a spring '61. This armature. structure".v 65'. is provided "with Ian attachedia'mnature -64 .nh'magn'etic material for '5 cooperating with the core structure 30. Also, suitable contacts for making and breaking front and back contacts are provided. The bias spring 61 has its tension suitably adjusted by the adjusting screw 68 having a suitable lock nut.

The armature member 55 has an extending forked portion 69 which extends around the plunger 62 and its supporting guide means so as to freely move vertically and to carry at its outer extremities a resilient connector 19. This resilient connector may be made of phosphor bronze spring or the like and extends downwardly through a hole in the base plate 3i of the inner structure 23 to engage the grasping finger portion H mounted on the locking stop member 52. Assuming the force drop lock plunger 62 to be released, that is, moved upwardly to a disengaging position, as above explained, then the energization of the electromagnet causes the armature member 65 to be moved to an energized position against the bias of coil spring 6'5. This breaks the back contacts of the associated con tact fingers and closes the front contacts. At the same time, the resilient connector T5 is moved upwardly and to the left, thus transmitting mo- I tion to the locking stop member 52 which rotates counter-clockwise as viewed in Fig. 5 to a position in which it does not block the guide holes 54 for the lock rod 56]. Under such a condition, any substantial force applied to the foot pedal portion II will be transmitted through the arm 49 to the lock rod 55 compressing the spring 5! and causing the lock rod to move through its guide holes 54 freely without interference from the locking stop member 52. When the pedallatch ll--I0 has been moved until its lower portion 56 contacts stop 51, the tappet bar 48 through its lost motion connection will engage the lever 41 to positively insure that the cam shaft 35 is assuming its biased position. Also, the pedallatch l i-lll will then have been moved counterclockwise as viewed in'Fig. 4 to such a position as to permit the hand lever 9 to be free for operation to an opposite position.

When the hand-throw lever ii is thus operated, the hold-open lever is moved to such a position beneath the pedal-latch lllfl, as can be seen in Figs. 2 and 4, as to hold the pedal-latch in a releasing position insofar as the hand-throw level" 9 is concerned even though the trainmans foot is removed from the pedal portion I I. This hold-open lever feature is necessary since the relatively strong spring 5| biases the lock rod and the pedal-latch l l-l0 toward a locking position, so that whenever the hand-throw rod 9 is restored to its normal position, and the bar is withdrawn from beneath the pedal-latch I ll0, it immediately engages the hand-throw bar 9. However, this does not cause the contact arm 39 to break its back contacts since the cam shaft remains in its biased position until the pedal portion II is lifted andthe arm causes the tapp t rod 46 to be moved to the left as seen in Fig. 4 to act through the lever 4! to compress the spring 31. In other Words, the lock latch contacts are not'actuated to normal positions until the pedal-latch II-l0 has been moved to such a position that the padlock detent I3 may be moved to hold the latch H) in a normal position in which the padlock P may be properly inserted.

Referring to Fig. 5, it will be seen that a sealed cover 12 is over a spring biased push button having a button portion 13, a biasing spring 14 and a water-proofing flexible cover'l5. This emergency sealed push button, when manually depressed, engages a slidable bar 16 which is held in its normal position by a spring pressed detent 11, but the depression of the plunger 13 engages the bar 16 and moves it downwardly (the detent recess 18 going past the detent Tl). The downward motion of the bar 16 engages an extending arm l9 connected to the latch contact arm39 so that the initial movement of the bar 16 causes the latzh contacts to be opened and the front contacts to be closed independently of the position of the cam shaft 35. After the initial movement of the bar 16 and the operation of the latch contacts, the lower end of the bar engages the locking stop member 52 to move it to a non-locking position. This cannot happen however unless the cam shaft 35 is in a biased position permitting the plunger 62 to be moved upwardly to a nonengaging position, which means that the padlock P must be removed and detent l3 actuated to release latch It! before the emergency push button can be effectively operated.

When the locking stop member 52 is thus released, the pedal-lat:h I l-l6 can of course be moved to a releasing position to allow hand operation of the track switch, but when the hand operation of the track switch has been completed and the hand-throw bar 9 moved to a normal position so that the pedal-latch member H-l9 can be raised, the tappet bar 46 causes the cam shaft 35 to assume its normal position and in so doing the plunger 62 is caused to force the locking stop member downwardly into a locking position. This movement of the locking stop member 52 restores the emergency release bar i6 only to a position where the detent 11 engages the recess 18. This means that the bar 16 still acts through arm 19 to hold the latch contacts open, even though the switch has been restored to normal and padlocked, Holding back contact 8| open holds the signals at stop, which condition continues until a maintainer is called to open the cover 26 and restore the bar 15 to its original position. This action of bar 16 guards against misuse of the emergency release by a trainman.

It should be understood in this connection, that the sealed cover 12 should not be opened and the emergency release button used except under proper emergency conditions, and under such conditions, the trainman at the switch has usually received permission from the central operator via'a telephone or other communication means that the switch lock is out of order, or the remote control thereof is inefiective, so that manual release is necessary and safe under the particular conditions in which such emergency release operation is to'be employed.

Referring to Fig. 6, the general functions'and operations of the electric switch lock can be considered with more particular regard to the specific sequences of operations for a particular operation. that the various parts in this functional diagram have been distorted in order to illustrate the functions, and the parts do not necessarily have the same structural forms as found in the structural figures of the disclosure.

More specifically, the removal of the padlock P and the upward movement of the detent l-3 permits the latch I ll to operate through a limited free movement so that the tappet bar 46 will allow the coil spring 31 to move the cam shaft 35 to a biased position. This allows the latch con tacts 8| and 82 to assume their biased positions It should be understood, however,

and close their front contacts. With front. con.- tract 82 closed, the coils of the electromagnet can be energized through suitable remote control means and any automatic circuits desired. The opening of the back contact 8| also causes the opening of the signal control circuit of: any signal or signals governing trafiic over the track switch W.

However, the trainman does not step on the pedal I I until the indicator. lamp 33 is illuminated, indicating that the remote operator and the automatic controls have released the electric lock by energization of the electromagnet 30. When the electromagnet is energized, the armature structure 65 opens back contact 84 and closes front contact 83. The. back. contact B l further opens the signal circuits, while front contact 83 energizes indicator lamp 33.

When the cam shaft 35 is. actuated to its biased position, the lock plunger 62' is moved to a nonengaging position by the spring 63. This permits the resilient connector 10 to operate the stop member 52 to a non-locking position by the energization of the electromagnet 30, thereby permitting the longitudinal movement of the lock bar 50 upon the application of downward force on pedal II. This movement of the pedal-latch Hi9 to a depressed position releases the hand-throw lever 9 and permits the operation of track switch W to an opposite position. While the handthrow lever 9 is out of its normal position, the hold-open bar 20 keeps the latch It in such a position that the lever 9 can be restored at any time. It is of course understood that the usual holding catch 85 (see Fig. 1) is used for the reverse position of the lever 9, and that this catch can be released by the trainman at any time.

The restoration of the manual throw lever 9 to a normal position allows the lock rod 50 to assume a normal'position by reason of the biasing spring and the hold-open bar 2!] permits the latch H] to assume a locking position. As above mentioned, the lifting of the pedal-latch H-|0 (as instructed on the pedal portion) allows the detent 13 to go into a position so that the padlock can be inserted and locked. At the same time, the tappet bar 46 causes the cam shaft 35 to positively assume a position which forces the latch contacts to their'normal positions and at the same time forces the plunger 62 downward to insure that the locking stop member 52 is in a locking position. It is obvious that this forcing of the locking member 52 to a locking position acts to apply pressure through the resilient connection in on the armature 65 and thus assure that. it assumes a deenerg-ized positiOn.

It can be readily seen that the use of the emergency release forces the latch contacts to open positions, but the stop member 52 cannot be moved to a non-locking position by the bar 16 unless the padlock has been removed and the pedal latch allowed to assume its initiating position to allow the plunger 62 to be raised by spring 63. In this way, misuse of the sealed emergency release is prevented by an unauthorized person not having a key for padlock P.

It will also be noted that the locking stop member 52 is of the statically balanced typeand the various jars, shocks and vibrations transmitted to the lock does not act to throw itout of a looking position while the padlock detent i3. is released. This is because such jars and vibrations act equally on all sides of the pivot point 53. It is also noted that any shocks or vibration which mi ht cause a slight amount of vibratory action on the armature structure is minimized by the use of the resilient connection III.

It is therefore believed that a reliable, positive acting, and efficient switch lock organization has been provided in accordance with the present invention, which organization is constructed so as to be immune to shocks and vibration and to be relatively free from moisture and frost conditions by reason of the double casing structure.

While the present invention has been described rather specifically, it should be understood that this description has been given solely by way of example, and is not intended in any manner whatsoever in a limiting sense. Obviously the invention can assume many physical forms, and is susceptible of various modifications, and it is intended to include in this invention all such forms and modifications as come within the scope of the appended claims.

Having described our invention, what we claim 1s:.

1. In an electric lock for hand-operated track switches, a manually operable lever for moving the, points of a track switch to their opposite positions, a manually operable catch for preventing operation of said lever subject to the release of an electric lock mechanism comprising a longitudinally movable cam shaft, contacts operated by said cam shaft to their. closed positions when said cam shaft is in a predetermined position, a lock member for preventing manual operation of said catch until released, electromagnetic means for releasing said lock member, and means for positively forcing said lock member to be in alocking position when said cam shaft is in said. predetermined position.

2. In an electric lock for hand-operated track switches, a manually operable lever for moving the points of a track switch to their different positions a manually operable catch for preventing operation of said lever when held in its normal position, means for holding said catch in its normal position comprising a lock bar associated with said catch and moved longitudinally when said catch is manually operated to a released position, a pivoted stop member normally preventing longitudinal movement of said lock bar to thereby prevent the manual operation of said catch, an electromagnet of the tractive type, and a resilient connection between said electromagnet and said stop member for causing a limited amount of rotation of said stop member when said electromagnet is energized to thereby release said catch for manual operation.

3. In an electric lock for hand-operated track switches, a manually operable lever for moving the points of a track switch to their opposite normal and reverse positions, a manually releasable catch for preventing operation of said lever from its normal position, a lock bar associated with said catch and moved longitudinally when said catch is manually operated to a released position,

a pivoted balanced stop member normally preventing longitudinal movement of said lock bar to thereby prevent the manual release of said catch, and electromagnetic means rotating said stop member a limited number of degrees on its pivot point to at times allow the manual release of said catch, whereby the balanced stop member is substantially immune to shocks and vibration which might otherwise cause a false release of said catch.

4-. In an electric lock for hand-operated track switches, a manually operable lever for moving the points of a track switch it their opposite normal and reverse positions, a manually operable catch for normally preventing operation of said lever away from its normal position, "a' lock plunger operably connected to said catch so as to be moved longitudinally by the operation of said catch to its locking and released positions, a locking member statically balanced on a pivot point for normally engaging said locking plunger to prevent said catch from being manually released, and electromagnetic means for operating said locking member to a non-engaging position, whereby said catch cannot be falsely released due to shocks and vibration since said balanced locking member is immune to shocks and vibration.

5. In an electric lock for hand-operated track switches, a manually operable lever for moving the points of a track switch to their normal and reverse positions, and an electric lock mechanism for normally preventing manual operation of said lever comprising, a locking plunger operable longitudinally to release said lever, a pivoted locking member statically balanced about its pivot point for in one position preventing longitudinal movement of said lock plunger and in another position for permitting movement of said lock plunger, an electromagnet having an armature normally biased to a deenergized position, and resilient means interconnecting said annature and said pivoted locking member, whereby energization of said electromagnet actuates said pivoted locking member to a non-locking position, and whereby holding of said locking member in either position does not prevent said armature from moving to a non-corresponding position.

6. In an electric lock for hand-operated track switches, a latch for normally looking a track switch to prevent operation of the track switch from its normal position, electromagnetic means for normally holding said latch in its locking position until energized, contacts manually operable from one position in which a signal circuit is closed to another position for permitting energization of said electromagnetic means, and means acting upon the manual restoration of said contacts to said one position for positively forcing said electromagnetic means to its normal position for holding said latch in its locked condition, whereby the restoration of said electromagnetic means is self-checking.

ii. In an electric lock for hand-operated track switches, a manual lever for moving the points of a track switch to their opposite positions, a catch for holding said manual lever in a particular one of said positions secured by a padlock in such position, a lock member for restricting the movement of said catch, a latch contact block having normal and operating positions, means effective after the removal of the padlock from said catch for causing said contact block to assume said operating position, electromagnetic means for operating said lock member to allow the complete manual release of said catch in response to the movement of said contact block to said operating position, and manual release means having normal and operated positions, said release means being effective when manually moved to its operated position for operating said lock member to allow the complete release of said catch irrespective of said electromagnetic means, and said means being effective to operate said lock member only when said padlock is removed from said catch.

8. In an electric lock for hand-operated track switches, a manual lever for movement of the aims-8t points ofa track" switch to their. opposite positions, a catch for. holding said manual lever in a particular'one off said positions and secured by a padlock in such position, a lock member for restricting the movement of said catch, a latch contact block having normaland operated positions, a spring for biasing said latch contact block to an intermediate position, means dependent upon the action of said spring for causing said contact block to assume said operated position after the padlock is removed from said catch, electromagnetic means for operating said lock member to allow the complete manual release of said catch in response, to the movement of said contact block to said operated position, manually operable means for operating said lock memher to allow the complete manual release of said catch irrespective of said electromagnetic means, said manually operable means being effective to release said catch only when said padlock is removed from said catch, and means for causing said latch contact block to be restored to its normalposition upon the complete operation of said manual lever and the locking of said catch by said padlock, only if such operation has been effected by said electromagnetic means rather than said manually operable means.

9. In an electric lock for hand-operated track switches, a manual lever for moving the points of a track switch to their opposite positions, a catch for holding said manual lever in a particular one of said positions, a lock member for restricting the release of said catch, a contact block having normally closed contacts, electror responsive means for releasing said locking member and thereby releasing said catch, manually operable emergency release means for releasing said lock member and thereby releasing said catch, and contact operating means for operating said contact block to open its contacts when said catch is released from its holding position, said contact operating means being effective to restore the contacts of said contact block to their closed positions upon the manual restoration of said catch to its holding position, only if the release of said catch has last been effected by said electromagnetic means rather than by said emergency means.

10. In an electric lock for hand-operated track switches, a manual lever for moving the points of a track switch to their opposite positions, a catch for holding said manual lever in a particular one of said positions secured by a padlock in such position, a lock member for restricting the movement of said catch, a latch contact block having normal and operating positions, means efiective after the removal of the padlock from said catch for operating said contact block to its operating position, electromagnetic means for operating said lock member to allow the complete manual release of said catch in response to the movement of said contact block to said operating position, manual release means having normal, intermediate, and operated positions, said manual release means bein efiective when moved to its operated position to allow the complete release of said catch, irrespective of said electromagnetic means, and said manual release means being effective only after said padlock is removed from said catch, means for operating said latch contact block to restore to its normal position after the restoration of said catch if the release of said catch has been effected by the operation of said electromagnetic means, and means for allowing said manual release means to be restored only to 1-1 12 its intermediat ze positionafter the locking of said UNITED STATES PATENTS. catch with sand padlock. Number Name Date OSCAR HELD-r 5:22 615 Beze M 18 '1897 W HEWES. W

2,019,462 Phmney Oct. 29, 193.5 REFERENCES CITED 2,360,956 McGowan Oct. 24, 1944 The following references are of i'ecord in the file .of this patent:

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