US2437328A - Electric switch lock - Google Patents

Description

' M r 9, 1 4 w. c. M WHlR'i'ER ET AL 2,437,328

ELECTRIC SWITCH LOCK Filed Jan. '50, 1946 5 sheet s-she ec l Zl\ 41/10 S a c j Y 3 g 5 I 4 1 a f BY Glezz V I9! 91 5011.

7 /1273 ATTORNEY March 9, 1948. w. C. MCWHIRTER ETAL 2,437,328

ELECTRIC SWITCH LOCK Filed Jan. 30', 1946 5 Sheets-Sheet 2 INVENTORS WZ'ZJz'azzz 0. wit 252 691 and aim THEIR ATTORNEY March 9, 1948. w. c. MCWHIRTER ETAL I 2,437,328

ELECTRIC SWITCH LOCK Filed Jan. 30, 1946 5 Sheets-Sheet 5 I N VEN TORS THEIR ATTORNEY March 1948. w. c. MCWHIRTER ETAL- 2,437,328

ELECTRIC swncn LOCK Filed Jan. 50, 1946 5 Shets-Sheet 5 VINVENTORS Wcllz'amz (J. miflzz'rten and BY Glen V. 1916 1 1 5012.

, first 771273 ATTORNEY greases 3 usually comprise a switch stand of conventional construction.

A lock rod I2 is attached at one end to the switch point H and is slidably supported at the other end in a suitable guideway l3 provided in the bottom of the lock support 2. Formed in the lock rod I2 is a hole |2a which, when theswitch point occupies the normal position shown, is adapted to at times receive a locking plunger I4 forming part of the electric lock, to lock the.

switch point H in its normal position.

The locking plunger I4 is pivotally attached to the lower end of an up-and-down rod I5 which extends upwardly with clearancerthrough the lock support 2 and is pivotally connected at its upper end to a crank I! mounted on an operat-- ing shaft l8 journaled in suitable bearings l9 provided in a supporting bracket secured to the bottom of the casing within the rear compartment'S of the casing. The front end of the" shaft l8 extends with clearance through a hole 2| provided in the partition wall 1, and has secured thereto within the outer compartment 8 an operating handle 22 by means of which the shaft can be rotated when and only when the front door 5 is open. The front door 5 is arranged to be "locked in its closed position by inserting a padlock 23 (see Fig. 2) through an eye 24 which is provided on the door 5 and which cooperates with a hasp 25 pivotally attached to the casing 1 adja'cent the side of the door 5 which swings outwardly when the door is open. The operating handle is adapted to be swungbetween two extreme positions determined by stop lugs 26 and 121 provided on the outer sideof the partition wall I, and the parts are so proportioned that when the handle is swung to the extreme position in which it engages the stop lug 26, which position we shall designate its locking position, the locking plunger I4 will enter the hole |2a in the lock rod l2 and lock the switch point II in its normal position, but that when the handle 22' is swung to its opposite extreme position in which it en- 'gages the lug 21, which later position we shall designate its unlocking position, the locking ."plunger M will then be lifted clear of the lock rod l2. It is desired to prevent the front door 5 from being closed except when the operating handle 22 is moved to its locking position, and to this end an arcuate lug 28 is provided on the door 5 in such a position that it will cooperate with the operating handle to prevent'closure of the door if the handle is not in its locking position.

A drum type controller 36 is mounted onthe operating shaft I8, and is provided with a plurality of contact bands 3| which cooperate with pairs of contact fingers 32 and 33 disposed on opposite sides of the shaft to form circuit controlling contacts responsive to the position of the shaft The contact bands 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 the lengths of the bands the contacts may be made to open or close in any desired position of the shaft. The contact fingers 32 and 33 are secured by means of terminal posts 34 to insulating terminal boards 35 secured at their ends to supports 36 provided on vthe supporting bracket 20.

'A locking segment 40 is formed integrally with ,the crank I1, and this segment is provided with a notch or shoulder 4| which cooperates with a locking dog 42. The locking dog 42 is secured by means of a finger 43 to a vertically swinging arwill be described in detail hereinafter.

mature supporting member 44, and is maintained against lateral displacement by a slotted guide member 45 (Fig. 5) formed integrally with the supporting frame 20. The armature supporting member 44 is pivotally supported intermediate its ends by means of trunnions 46 journaled at their ends in trunnion screws 46a adiustably screwed through depending lugs 41a provided on a supporting plate 41 bolted to the upper end of the supporting frame 26, and carries an armature 48 which cooperates with pole pieces 49 formed on the lower ends of the cores 50 of an electromagnet L. The cores 50 are mounted in parallel spaced relation in the supporting plate 41 and are connected together at their upper ends by a backstrap 5|. Surrounding the cores are coils 52 which will usually be connected in series in such manner as to produce cumulative fluxes in thecores when these coils are energized, and which coils together constitute the energizing winding for the electromagnet.

The notch 4| in the locking segment 46 is so "disposed that it will align with the locking dog 42 when and only when the operating handle 22 is rotated to its locking extreme position, and the parts are so proportioned that when the notch I4| is in alignment with the locking dog 42, the

dog 42 will enter the notch due to gravity or will be lifted clear of the notch according as the electromagnet L is then deenergized or energized. It follows that When the operating handle 22 occupies its locking position, it cannot be moved away from this position unless the electromagnet L is then energized to lift the locking dog 42 out of the notch 4|, or unless the locking dog is manually lifted out of the notch in a manner which The energization of the electromagnet L will usually be effected as the result of the closing of a remotely controlled circuit which is rendered .available by the opening or closing of contacts actuated by the 'opening of the front door 5, as will appear here- "inafter.

The armature supporting member 44 extends rearwardly past its point of pivotal support and has secured thereto at its rear end an adjustable icounterweight 53 the function of which is to counterbalance the weight of the armature and the locking dog 42' a sufficient amount to enable the locking dog to be lifted out of the notch 4| in response to a reasonable degree of energizetion of the electromagnet L.

The locking dog 42 is operatively connected by means of a vertical rod 55 (Figs. 3 and 4) with a pivoted indicator 56 visible through a window 5'! in the partition wall 1 of the casing I. This indicator may assume a variety of forms, but in the form here shown consists of a pivoted arcuate member 58 positioned behind the window 51 in such manner that it will indicate locked or unlocked according as the locking dog 42 is within the notch 4| in the locking segment 46 or is swung upwardly to the position in which it is clearof the locking segment.

shcwmtheparts arc so armngedithat thesflngers mll'he moveu: to th'e lflsiflbfi'siifi -wmli the-con!- t'actsiorrned 'thereby'willi bewclcsed or: open a c-'- cording: as'thciocking new! *occupiesits: locking or itsunlockingposition;:buticshouldb'eipointed out that where desirabiefor special" applications the fingers et'leithenone orBoth ofrthe contacts may be reversed: contacts will: be 'open 'o'r clcsed accordin thera y-42 occupies its lockinrg cr ts-unlockm'g positiom a whc enr tl'ies'e =portioti=s '0-the lock will be apparent mm :an inspection the drawin'g'swithout-:further detailed-dawn ption.

According to ur presehtrinventiomthe lockis partition-wan 1', andiseonstantly biased to an outer position by *means' of a -'c'ompr-essed coil spring'fi'i disposed cnjtff rcr'r between the side "lea oi-the frame-ils and a rigidarm 18" which is pinned atone end to th rod [0. The outer end of the-m'dlil' cooperates 'the 'head of a stud T9 adjust'abl'y mounted-m =boss '80 provided on theinner f'ace eithemain do'or'i of the casing I. The'stud 1 9 issoiadjustedithat"when-the door 5 isclosed', the headof the stud will engage the rod 1 0 and will force it inwardly in opposition to the bias o'f the s'p ri'ng H toan' inner position in which the inner endof'the' arm= Ris-spac'eda slight distance from the-side7 3it er the bracket 13.

A lever arm- 81 *(Flgsze a'rid '6') is pivotally mounted at one end ona' pivot: pin 82' secured to the supporting-plate l'l 'asn'd-is pivotally connected at" one" endby means or apiii and slot connection to the-inner end'ofitherieidarm 18. A leaf Spring amofphosphor bronze or the" like is secured to one side of the ann 81', and this spring cooperateswith arr upstanding arm 83 provided on the armature supporting member 44 in such manner that when-the pus-h rod 10- is moved in- Wardly to its innerlposition by the'closing of the door, thespring'Mo will-engage'the arm 83 and will-exert a force on: thisarm sufficient to urge thelocki'ng dog-toits locking position and to retain it there irr'especti've of Vibrations which may-"be transmitted to therock due to passing trains, but=t hat,*when the'push' rod is permitted tomove to its" outerposition'due to the opening' of "the door 5,"t-he spring OM will then be swung clear of the armfis-a sumcientamount to prevent it from exerting any Iorceonthe-armature supporting-member 'll whfch would oppose that duetcthe energization of the-e'iectromagnet Attache'd' to the outer'ei-id of 'ther'od- 10 is a flexible weatherproof covering- "which acts to prevent the-entry of moisture into" thecasingl through the' open'i'ng '16 around' the rod; [0. I

The ro'd lfl cooperates at its inner end with a movable contact-lingerfi' secured' by means of terminalpostsSe eneEl -tonne side of the terinmai board w. 'rhe nnse' was: rsinsu' dated from we therod 'mzbyzarrinsulaaingstnip'm scui'editdffh finger an'dcooperatesiwithz'atfixedi contact rfinger 89 toi-formi a1 conta'ctw88-.-&9.; f The finger 89 is.se:.- cured to the oppositersideofithe terminal board from the fingerJBS- by means ofsthezterminal .posts 86 and-81- and isiinsulated 'firomthe terminal post 86 :but' iselectricailly' connected with the terminal post 8-1. The: finger iiis: irisulatedi-from the terminal post- 8 1 but is electrically: connected; with the t'erminallpostzafit lt'will bie apparent, there.- fore; that thenpostis lifi and Bltnotronly provide a means for. securinQi'theF contact fingers; tothe terminal -b'o ard but also? provide. a means: fores tahli'shing -eiectri'cali connections-with these fingers. The parts are'irso arranged that the; contact 85'89 will be clo'sedor openaccording as the rod 70 occupiesiitsa inneriiposition or is moved to its: outer p ositirmi This :contact: maybBllSGd to indirectly control: the energlzationofi the. electroma gne't L or -fO1 "2;ILyIO't1 IBf desiredipurpose;

'It should he rnoted that whllez the contact 85--89' as shown is; arranged: tovbe'zcl'osed' when the door is closedtandiopertwhen thesdonr. isopen, this: contact may: readilyzbeareversedl in accordancewithwellknown-practice.-

The emergency release mechanism in the; form here show-ricoinprises -a push-rod: eflz slidably supported in -thesiiiesl3a and 13bf0f'l7hh supporte ing bracket 13 above the operating rod 15. This rod is formed with 'arnloffset portion which extends outwardly through a. clearance hole. z9l provided in the partitionuwall 51 and has secured its outer end a push 'buttorrknohsz, The rod is biased to anouterziposition by meansof a com:- pressed coil spring '93: whi'ch;surrourrds'th-e rod between: the side 13w of'tlre'bracket-lzi and a collar 94 pinne'd tothe'rod. :Itma'y besealed in this position by means of a blockingi arm which is attached at oneend byyme'ans oi 'a pinrSfi to the outer side of the partiti'om wall- L The arm 95 is provided: with a tslotted'portionafira which, when thearm is rotated; toithezextremeposition shown, extends between the-partition. wall and the push buttonin such'mannerfthat it is. then impossible to move thexpush :ibnttoir inwardly from its outer: position lr'llh'e blocking arm, however, may be rotated to another'position in which the slotted portiom 9'5a is withdrawn from behind the push button When the blocking. arm occupies its blockingpositi'on; it engagesa stud B l-secured to the-:xpartition wall I, andthis stud is providedwith raihhl'e whichra-l-igns: with a hole in the blockinga-armto .enable a;. sea1 wire 818 to be passed through these-parts in such manner that the blockingamt;icarrzonly be rotated away from its blockinglpositionv-by' breaking' this seal wire.

The push rodfifl i'szprovided Jadj acent r its inner end with a; collar- .1 00 GEEMYiIIg'lS; flexible. or spring rod ll)! which cooperates-with. the upstanding arm 83 on the armature supporting member i at the opposite side of the. arm from-thespring Bla. The-parts are so proportioned thatwhen the push button 92 is moved't'oits inner position,

the. flexible rod: I M- will. enga'ge the "arm as and will move the arm "far enough to lift thelocking dog clearoftheunotch' 41 in the locking segment 4fl if the flexible spring'flla is out of. engagement with the armr'as-will be the case when the door 5 is open. However, if the door-5 is closed, the force exerted: onthearm 8'3 by theflexiblerod It! will be insufficient to overcome the opposing force due to the spring 81a.-

The collar: Mill cooperateswith alatching member] 02 secured by 'meeznswof a; flexible strip I33 to the upper side of the supporting frame 13 in such manner that when the push button 92 oocupies its outer extreme position, the latch will rest on top of the collar, but that when the push button is moved to its inner extreme P sition, the latch will then move downwardly due to the bias of the flexible supporting strip [03 to a position behind the collar I06 and will thus act to latch the push button in its inner extreme position. The outer end of the flexible supporting strip H13 is bent upwardly and outwardly to provide a finger grip Him by means of which the latch may be restored to its unlatching position after it has once been moved to its latching position. It will be obvious that in order to gain access to the latch it is necessary to open the rear door 6 of the mechanism case and since this case is locked by a lock which can only be opened by the maintainers key, it is impossible for a trainman after he operates the pushbutton to restore it to its unlatched condition. To prevent damage to the latch by moving it upwardly an excessive amount when restoring the latch to its unlatched position after it has been moved to its latched position, a screw stop I04 is provided. The shank of this screw extends through a clearance hole in the latch and is screwed into a tapped hole provided in the upper side of the supporting bracket 13.

The push rod 90 cooperated at its inner end with a contact comprising a flexible contact finger I05 and a fixed contact finger I06. These contact fingers are secured to the opposite sides of the terminal board 69 by means of terminal posts I01 and I08 in the manner similar to that in which the contact fingers 85 and 89 are secured to the terminal board and are so arranged that the contact formed thereby will be closed or open according as the push button occupies its outer or its inner extreme position.

The operation of the lock as a. whole is as follows: When the switch point ll occupies its nor-- mal position as shown in Fig. 1, both doors of the electric lock are normally locked in their closed positions and the switch is accordingly locked by engagement of the locking plunger M with the notch i2a in the lock rod l2. Assuming now that a trainman desire to reverse the switch S, and has obtained the necessary permission to do so, he will remove the padlock 23 from the hasp 24 on the door 5 and will then open the door. The opening of the door will permit the push rod to move to its outer position and will thus cause the contact 85-89 to move from its closed to its open position. 'If conditions are such that it is safe to reverse the switch without endangering trafflc, the opening of the contact 85-89 will ordinarily cause the electromagnet L to become energized by virtue of circuits forming no part of my present invention, and the energization of this electromagnet will move the armature 48 to its attracted position. This movement, in turn, will lift the locking dog 42 out of the notch 4| in the locking segment 40 and will thus unlock the lever 22. This movement of the armature will also operate the contacts 61-63 and 62-64 and will thus provide a means for indicating at a distance control point that the electric lock has functioned to unlock the switch. The movement of the armature to its attracted position williurther act through the armature supporting member 44 and the rod 55 to move the switch indicator from the position in which it reads locked to the position in which it reads unlocked. As

- soon as this. indicator moves to thi latter posttion, the trainman knows that the lever is un- -locked,and he will then operate the lever 22 from its locking position to its unlocking position whereupon he may reverse the switch points by means of the usual switch stand or other switch throwing device. The operation of the lever to its unlocking position will work the contacts of the drum controller connected therewith and will thus provide a means for conditioning any circuits controlled thereby in accordance with the positions which the parts then occupy.

After the switch has been reversed in the manner just described and it is desired to restore it to the position shown, the trainman will first return the switch point to its normal position by means of the switch stand and will then restore the lever 22 to its locking position. The movement of the lever to its locking position will cause the locking plunger to reenter the notch PM in the lock rod and will thus again lock the switch point II in its normal position. As soon as the switch point has been locked in its normal position, the trainman may then close the door and replace the padlock 23 in the hasp 24. The closing of the door will move the operating rod Ill inwardly against the bias of the spring T! which latter movement, in turn, will close the contact -89 whereupon the electromagnet L will become deenergized through controls not shown. The inner movement of the push rod will also act through the arm 18 and. lever 8| to cause the spring Bla to exert a force on the arm 83 of the armature supporting member 44 which force will act to insure that the locking dog will reenter the notch 41 in the locking segment 40 and will be prevented from vibrating within the notch.

We shall noW assume that a trainman desires to reverse the switch in the manner previously described but that when he opens the door 5, the electromagnet fails to become energized due to some unusual condition such for exam-pie as a power failure, or a failure of some part of the energizingcircuit for the magnet to function as intended. Under these conditions the trainman after obtaining permission so that his action is recorded-by proper authority will remove the seal 98 and will then rotate the blocking arm upwardly from its blocking position to a position in which it is out of the path of movement of the emergency release push button 92. As soon as the blocking arm has been rotated to this position, the push button 92 may be operated. 0p eration of this push button will first cause the contact lll5-l 66 to become opened and will then cause the latch I62 to drop down behind the collar we and thus latch the push button in its inner extreme or operated position. The inward movement of the push rod will also act through the spring rod lotto exert a force on the arm 83 carried by the armature supporting member 44 suflicient to lift the locking dog from the notch 4| in the locking segment 40, It will be remembered that the opening of the door 5 permits the operating rod ill to move outwardly due to the bias of the spring ll so that when the push rod 9c is move-dinwardly under the conditions just described, the leaf spring iila will have been rotated to a position in which it will not oppose the motion of the armature supporting member by the spring rod I61. It follows that it is possible for the locking dog to be moved to its unlocking position under these conditions without interference by the forced drop mechanism of the lock. The parts are so designed and so proportioned that the movement whichthe spring rod Hll will a: havei-imparteditoztheia a8z8 whemtnezpusnlbutton-hastbeem movedijusiz tameneuehstoiopemthei contact:- ME -mid andz permit; the: latch; t'oi drop dowm liehimitthe collarslllfliwillinot-be suificient. to2completeiyliitzthezlochineidoeroutrofithernotch; 41 so that, im order: to lifts thexdog; clean of: the, notch: in will: bei necessarae for, the: traimnamto push: the push: button: 92. to;:the.. extrema-inner-- end ofits-strok-e; 'Ifhea-reasomfor this? proper-' tioning of t-herpartssis-l to makeaitdmpossibleitoi obtain 7 an: unlock: ofirthezswitchsuntilethersignals-i have b een place dwin-theinmestrictivezlwsitionsaandi the contacts .=latched:openr Ass'soczt as. thefil-Q kw ingr-doghas been-flirted; cleaner; thevnotch; thee trainman: maythen. proceed-i 110;" unlock; and ire-- verse; the.- switch: in; the-emanneh previouslydc scribed; When: the emergency pushbuttom has: become latched; inz-- the-manner: previously olescribed; it remains; latohe'eb against fur-then ma.

trolled; byv-theg a-pusnbutton'ivliilhnormally:harem? played; to- CDi'l-I-IDjle the; signals; governing; trafficmovementssoizer t-he l srvitehw and it: follows that: thezlatch ,mechanism providesalmeansforguardeingg against. asdangerousrconditiontduef toscarer- IBSSHBSS-r omthesparti otaetrainmam since while the: switch maybe: restorerntmits :normal position: and: relo ckedz im thisrpositiom it .isyimpossibley for: thB?-t1ainman tci-unlaclomanushibutt e fact that itr is 'nebessarry 'forrthe trai-nmam to: break a: sealiinzonderrtb;.op;emte the push -v button leaves:attel-ltaleethatwtheslookihassbeen operated.- under: emergency; conditionswby propen au h y: SO," that: thesma-intainer wi-llgimmediately b notie lied to restore the cbnd-itionsrtn normal; The, maintainer will thereupon opens the rear? door andvlift the latch: cleanzoiethewcollan 0 1 which: will'permin-the oush ;button toireturnstosits: outer: position: soon: asflthezepusha button-l-hastbeem returned to itsoutenposition, theinrain-tamer!willsv then: restore theiblocking arm mills a-bleeking poesition and-will; seal it; in? thisapositienabma newe seali Bothr'doors may; thembe returnedttoatheir. normal:locked-positions and? allvp rtsvwilllbe re. stored. to, their normals onerati-ng; positions; in which: they: are illustratedain the? drawing It-l-shouldlbepointed outsthat :the design: ofrthev spring; rod-.- Hit. is suoh, --that it is: .possible: after' the: push-button f has lzbeenemovedntotitsr emer, genoyrelease position and: latched there to close the main! door oivthecase. thenormalsmanner to thereby oause-thenormalq forced.- dropandr antiwi'bration; forcefexertediby; theespring- 8| a to be applied to the-armatunez,

It: should-also? beepointed out that after the.- emergency release:- p ush \buttorr/h-asebeen once latchednin itsoperatedpositiomandy-the door? 5: isropened, the locking dog -isxheldsirr locked position-s unless.the-trainmampushesetheabntton: 92;- in. order. to; again:causeethezlocking-adog; to; moveto. its uniciCkiHgt-HOSHHQRJ Duringe this op'erationqif; the rwayside'signals arstdontrollflbmthmcontacts lli'ziFia-nd Hi6? as: will! n'ormal'lwbe the tease; these: signalszwilr continue ltozdisplay their most frestric-z tiveindications Iffthereforemecomes a matter of 'urgent'rn-aintenancethat where it; hl'as on'ce -been found necessary to operatemhe emergency release mechanism immediate steps 's-hould betaken to restore-all parts totheii normal positions by the; maintainer; j j

Although we'hlave; herein shown and described only one form of electric lock'embodyingpurtinvent-ion,. itis understood thatg'various changes 'and modifications may"be .madetherein within .the

10' scope oi the appended, claims without departing? from the. spirit-and scopeL-otour invention.

Having thus desoribedfmyv invention, what we claimis:

1. v A, locking? device lion-railway trafilc, controleling apparatus comprising I a locking. segment,- manually operable means: connected with. said, segment for movingsaidrsegment betweenltwoexe. treme positions, alockingdoa adapted. to engage.- said segment in.- one extremev position-to prevent movement of said segment away. from such. ex.-. treme position, electrically controlled means eiiective when energized for, moving, said locking dog to, an, unlocking. position, an emergency rte-a lease push),- button.v biased} to, one. position, means, controlled bysaid.pushbuttonlandlefiective when said lpushlbutton is moved from .saidione, posit-ion. tor-another positiontotmove 'saidl'loicking, dog toitsunlock-mgr position,,-latcl i. means efiective. when 203 said -.push button ismovedpart way, to, said other position for subsequently preventingfiaidlpush button) from. returning. to ..its, one position until said latch meansis; manually operated; to, release said. push button,,:and; contact; means selectivelyl responsive tothe latched and unlatched positions of,.said push button.v

2, A locking device for railway traiiic control ling apparatus, comprising a locking segment, manually operable, means connected with said segment. for movinggsaid" segment between two extreme positions a locking Cl'Qg adapted to en eagesaid seement' n one-extreme-p nt Pr s vent movement of, said, segment away. from such extreme position, electrically controlled means efiective, when energizedjtor moving said locking dog. to an unlocking position; ian emergency release push button bialS dQtQ 6. lQQ m a s controlled bysaid, push button and effective. when, said. push button is movedi'fromlsaid one, position to, another position to movesaid'locking dog to its; unlocking position latch means effective when said pushbutton is; moved part way. to said other position for subsequently preventing. said push button from returning to its one position until Said latch means is manually operatedto release saidpush. button, contact. means operated by movement of said push button from its one to. its latched position, a blocking'lever' movable between a. normal position in whioh it prevents operationof said push button away from its one position and another position in which it is out of the path, of movement of said push button, and a removable sealior sealing said, blocking lever in its normal position, saidf seal bein constructed. to be destroyed by its removal to provide a telltale when said sealis removed.

3. A locking device for railway'trafflc controlling apparatus comprising a casing provided with front and rear doors and divided'by means ofv a partition wall into front and rear-compartments, a trafiic oontrolling yshaft disposed in said rear compartment and connected with an operatinglever disposed in said" front compartment, said operating lever; being mova-bl between locking and unlocking positions; means preventing the closing oi said front door except when said lever occupies its locking position, a locking segment connected to sai-d"'shaft, a'locking dog movable between locking, and unlocking positions and effective when said lever and said "dog bothoocupy their locking positions to' engage said segment to prevent movement of said" lever away from its locking p osition; electrically controlled means effective whenenergized to movesaid lockingr'dog to its unlocking position, an operatingrod biased to an outer position and movable to an inner position in response to the closing of said front door, means connected with said operating rod and effective when said operating rod is moved to its inner position to exert a force on said locking dog which biases it to its locking position, a push rod movable between inner and outer positions, a pushbutton secured to said push rod within said outer compartment, means biasing said push rod to its outer position, other spring means connected with said push rod and effective when said push rod is moved to its inner position to exert afoice on said locking dog which biases it to its unlocking position. latch means effective when said push rod is moved part way to its inner position for preventing it. from returning to its outer position. said latch means being accessible only through the rear door of said casing, and contact means selectively responsive to the latched and unlatched positions of said push rod.

, 4. A locking device for railway traflic control-' between locking and unlocking positions and effective when sa d lever and said dog both occupy their locking positions to en age said se ment to prevent m vement of said lever away from its locking. position. electrically controlled means effect ve when energized to move said lookin dog to its unlocking position. an o erating rod b ased to an outer position and movable to an inner position inresponse to the closing of said front door, sprin means connected w th said operating rod and effective when said operating rod is mov d to its inner position to exert a force on said lock n dog which b a es it to its locking. position. a push rodmovable between inner and outer posit ons, a push button secured to said push rod w thin sa d outer compartment, means biasing said push rod to its outer position, other spri g means connected with said push rod and effect ve when said push rod is moved to its inner position to exert a force on sa d locking dog which biases it to its unlocking position. latch means effective when said push rod is moved part way.

toward its inner position for preventing it from returning to its outer position. said latch means being accessible only through the rear door of said casing. cont-acts operated by said push rod to one position or another according as said push rod occupies its outer position or is moved toward its inner position at least as far as its latched position, a blocking lever movable between a normal position in which it cooperates with said push button to prevent operation of said push button away from its outer position and an operated position in which it is out of the path of movement of said push button, and a removable seal for sealing said blocking lever in its normal position, said seal being constructed to be destroyed by its removal.

5. A locking device for railway traffic controlling apparatus comprising a casing provided with front and rear doors and divided by meansof a partition wall into frontand rear compartments,

12' a trafllc controlling shaft disposed in said rear compartment and connected with an operating lever disposed in said front compartment, said operating lever being movable between locking and unlocking positions, means preventing the closing of said front door except when said lever occupies its locking position, a locking segment connected to said shaft, a locking dog movable between locking and unlocking positions and effective when said lever and said dog both occupy their locking positions to engage said segment to prevent movement of said lever away from its locking position, electrically controlled means effective when energized to move said locking dog to its unlocking position, an operating rod biased to an outer position and movable to an inner position in response to the closing of said front door, spring means connected with said operating rod and effective when said operating rod is moved to its inner position to exert a force on said lockingdog which biases it to its locking position, a push rod movable between inner and outer positions, a'push button secured to said push rod within said outer compartment, means biasing said push rod to its outer position, other spring means connected with said push rod and efiective when said push rod is moved to its inner position to exert a force on said locking dog which biases it to its unlocking position, latch means effective when said push rod is moved part way toward its inner position for preventing it from returning to its outer position, said latch means being accessible only through the rear door of Said Casi and contacts controlled by said operating rod and said push rod.

6. A locking device for railway tramc controlling apparatus comprising a casing provided with front and rear doors and divided by means of a partition wall into front and rear compartments,

a traffic controlling shaft disposed in said rear compartment and connected with an operating lever disposed in said front compartment, said operating lever being movable between locking and unlocking positions, means preventing the closing of said front door except when said lever occupies its locking position, a locking segment connected'to said shaft. a locking dog movable between locking and unlocking positions and effective when said lever and said dog both occupy their locking positions to engage said segment to prevent movement of said lever away from its locking position, electrically controlled means effective when energized to move said locking dog to its unlocking position, a supporting bracket secured within said rear compartment, an operating rod slidably supported in said supporting bracket andextending into said outer compartment through a hole provided in said partition wall, means for constantly biasing said rod to its outer position, means on said front door cool erating with the outer end of said operating rod when said front-door is closed to move said operating rod to an inner position, a lever pivoted at one end and operatively connected at the other end to a, rigid arm attached to said operating rod, a leaf spring secured to said lever and effective when said operating rod is moved to its inner position to exert a force on said locking dog to bias said locking dog to its locking position, a push rod slidably supported in said supporting bracket and extending into said outer compartment through a hole provided in said partition wall, a push button secured to the outer end of said push rod, spring means biasing said push rod to an outer position, latch means se-' when it is moved more than a predetermined.

amount toward its inner position, contacts operated by movement of said push rod from its outer to its latched position, and other spring means connected with said push rod and efiective when said push rod is moved to its inner position to exert a force on said locking dog which biases it to its unlocking position, said other spring means being weaker than said leaf spring..

7. A locking device for railway trafiic controlling apparatus comprising a casing provided with front and rear doors and divided by means of a partition wall into front and rear compartments, a traffic controlling shaft disposed in said rear compartment and connected with an operating lever disposed in said front compartment, said operating lever being movable between locking and unlocking positions, means preventing the closing of said front door except when said lever occupies its locking position, a locking segment connected to said shaft, a locking dog movable between locking and unlocking positions and effective when said lever and said dog both occupy their locking positions to engage said segment to prevent movement of said lever away from its locking position, electrically controlled means effective when energized to move said locking dog to its unlocking position, a supporting bracket secured within said rear compartment, an operating rod slidably supported in said supporting bracket and extending into said outer compartment through a hole provided in said partition wall, means for constantly biasing said rod to its outer position, means on said front door cooperating with the outer end of said operating rod when said front door is closed to move said operating rod to an inner position, a lever pivoted at one end and operatively connected at the other end to a rigid arm attached to said oper- 14 ating rod, a leaf spring secured to said lever and effective when said operating rod is moved to its inner position to exert a force on said locking dog to bias said locking dog to its locking position, a push rod slidably supported in said supporting bracket and extending into said outer compartment through a hole provided in said partition wall, a push button secured to the outer end of said push rod, spring means biasing said push rod to an outer position, latch means secured to said bracket and cooperating with means secured to said push rod to latch said push rod in an intermediate position following its movement to its inner position, contacts responsive to the position of said push rod, other spring means connected with said push rod and eifective when said push rod is moved to its inner position to exert a force on said locking dog which biases it to its unlocking position, said other spring means being weaker than said leaf spring, a blocking lever pivotally attached to said partition Wall for movement between a normal position in which it cooperates with said push button to prevent operation of said push rod away from its outer position and an operate-d position in which it permits movement of said blockin lever, and removable means for sealing said blocking lever in its blocking position.

WILLIAM C. MCWHIRTER.

GLEN V. JEFFERSON.

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

UNITED STATES PATENTS Number Name Date 582,615 Bezer May 18, 1897 914,447 Neubert Mar. 9, 1909 1,710,668 Stephenson Apr. 23, 1929 2,390,815 Steiner Dec. 11, 1945

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