US2571969A - Emergency release for locking devices - Google Patents

Description

Oct. 16, 1951 w. vENs 2,571,969

EMERGENCY RELEASE FOR LOCKING DEVICES Filed April 25, 1947 2 SHEETS-SHEET 1 :llii

-22 EzZ////// ////f //////f/ //////////A IN V EN TOR.

[said Velzsel. BY 4 I Z HIS 47 7 01210?! fiatented Oct. 16, 1951 UNE'EED STATES PATrENT OFFICE EMERGENCY RELEASE FOR LOCKING DEVICES Isaiah W.'-Vense1, 'Wilkinsburg, Pa., assignor to Westinghouse Air Brake Company, a corporation of Pennsylvania Application'April-ZB, 1947,-Serial No. 743,833

9 Claims.

My invention relates to emergency release 'for locking devices, and particularly. to :emergency releases for locking devices having positive forcedown features for a locking dog.

Operation of the operating member between its locking and unlocking positions is controlled by a'lock arrangement usually comprising a locking segment operatively connected with the operating member, and a locking dog movable into and'out of locking engagement With'the locking segment.

The locking segment is provided with a shoulder which cooperates with the locking dog in its looking condition to prevent movement of the operating member from its looking to its unlocking position until such time as the locking dog is withdrawn from the path of movement of the shoul- -der. The locking dog is operated by anysuitable means, such as by an electromagnetorby a mechanically operated time release mechanism,

'andin order to assure that'the locking dog-will bepositioned in looking engagement with the segmember. When the operating member is moved -through the firstfewdegrees of rotation toward its unlocking position, the projection carriedby the locking segment is .:moved clear of the depressor member, whereupon. the operating mechanism immediatelyxsnaps'the lockingpdogout of the pathnof the Segmentshoulderso that the operating member canbe-moved without interruptiontoi its unlockingposition merely by action of the operator in; throwing the operating member after the unlocked indication has been displayed.

-As i customaryinidevices of this character, "means arerequired to provide for" emergency re- "lease of'the locking 'in the eventbf'aa failureiof the dog operating .mechanisinto operate properly. It-is desirable thatthe emergency release means: providelioran operationisimilar :to: that obtained: in. normaloperation, that is, that after 0 I effecting anemergency release andobtainingian indication of that condition, the. operator will :be ableto throw the :operatingt'member to its .unlocking:positionimerely .by acting .upon the top- -erating member alone. In'suchcase,therefore,

the emergency releaseimust be eiiective when ment, the looking segmentis provided'with a projection which cooperates with a i depressor member connected with the lockingdog for positively forcing down the locking dog into locking engagement with the segment when the operating member is operated from its unlocking to its locking position. The projection on the locking segment moves in conjunction with the segment and in a portion of the stroke of the-segmenten- .gages a cammed surface formed onthe depressor member to force that memberdownwardly so that its cammed surface is positioned beneath the projection. With the projection in this position, upward movement or" the dog required to liftit' out of the path of thesegment shoulder will be limited by the engagement of the cammed surface of the member with the underside of the segment projection.

In normal operation the parts are'arranged so brought into play to establish a condition which :remains unchanged during the coursev of operationof the opera'ting..member t its unlocking position.

It is an objectiof my invention to provide: novel and improved'emergency release means for locking'devices incorporating positive force-down fea- "tures fcr the locking dog, and which release imeans is arranged when brought into operation -to establish a condition which remains un- -changed throughout the operation of the operating member to its unlocking position.

Another object'of my invention is to provide novel and improved means-effective to providean "emergency release for locking devices arranged to permit operation of "a locking dog to itsunlocking position when the depressor member of the looking dog is in cooperating relation with a drawdown projection of the locking segment.

Another object of my invention isto provide a "novel and improved emergencyreleasefor locking devices having positive force-down features for the locking dog.

Another object of my invention is toprovide novel and improved means for'obtaining' emer- 1 gency operationof locking devices.

The above-mentioned and other important objects and characteristic features of my invention are obtained by providing the locking device with a manually operable'plunger arranged to swing a pivoted depressor member of a locking dog out of engagement with a draw-down projection on the locking segment and subsequently to force the locking dog out of the path of movement of the locking segment shoulder.

Other important objects and features of my invention will be apparent from the following description.

I shall describe one form of apparatus embodying my invention and shall then point out the novel features thereof in claims.

Referring to the accompanying drawings, Fig. 1 is a front view with a portion broken away, showing one form of locking device provided with an emergency release embodying my invention. The portion broken away in Fig. 1 is shown in section taken on the line A-A of Fig. 3. Fig. 2 is a side view, partially in section, of the locking device illustrated in Fig. 1. Fig. 3 is a top view of the locking device shown in Fig. 1, with housing 60 and certain of the parts omitted. Fig. 4 is a partial view showing an arrangement of the parts which form a part of the locking device shown in the drawings. Fig. 5 is a side view showing an arrangement of some of the parts of the emergency release comprising my invention. Figs. 6 and 7 are side and end views, respectively, of the depressor member 4|.

In each of the several views similar reference characters refer to similar parts.

Referring to the drawings, a locking device having positive force-down features for the looking dog and provided with an emergency release embodying my invention is represented, for example, in the form of the well-known tower indicator comprising a face plate l0, secured as by tap bolts H to a base l2. Plate if! is provided with an opening i3 which aligns with an opening l4 provided in a supporting member I5 secured by bolts IE to the base i2. shaft I! is mounted in the aligned openings l3 and [4 to project past the face plate I!) and has provided thereon an operating handle l8. A drum type circuit controller is provided for operating shaft H and comprises a plurality of contact bands |El mounted on insulation carried by shaft 11, and which bands |9 cooperate with pairs of contact fingers 28 (see Fig. 4) secured by means of terminal posts 2| to insulation terminal blocks 22 which in turn are fastened by tap screws 23 to base plate 12. Shaft i7 is also provided with a crank arm 24 formed with an elongated slot 25 in which is mounted a driving pin 26 carried by a locking member 21. The locking member 21 as shown in Fig. l is adapted to be moved into and out of locking engagement with a lockable member 28, and when in locking engagement with member 28 projects into an opening 29 formed in member 28 to prevent movement of the latter member. Shaft I! also is provided with a locking segment 38 having a notched or cut-away portion provided with a shoulder 3| which cooperates with a locking dog 32 pivotally mounted for movement into and out of the path of movement of shoulder 3|.

The operation of dog 32 into and out of the path of shoulder 3| may be effected in any suitable manner commonly employed in looking devices of the type employed in railway signaling and traflic controlling systems. These means may, for example, comprise a time element device of the type shown in a copending application for Letters Patent of the United States Serial No. 734,273, filed March 12, 1947, by Kenneth J. J. McGowan, now Patent No. 2,520,848, dated August 29, 1950, for Looking Devices, or may as An operating shown comprise an electromagnet L having two cores 33, each surrounded by a magnetizing coil 34, mounted in parallel spaced relation on supporting member 15 and connected together at their lower ends by a back-strap 35. An armature 36 carried on an armature supporting member 31 pivoted on trunnion screws 38 threaded through suitable openings provided in the upper portions of supporting member I5, is disposed in magnetic relationship with the upper ends of cores 33 so as to be attracted to the cores when coils 34 of the electromagnet are energized. The electromagnet L may be provided in the usual manner with armature operated contacts comprising a stationary contact element 41 carried by a supporting bracket I5 anda movable contact element 48 carried by a dependent member 49 attached to armature supporting member 31 and arranged to be moved into and out of engagement with contact element ill according as armature 36 is in its attracted or released position, respectively. It is, of course, obvious that by varying the arrangement of the parts 41 and 48 the contacts formed thereby may be arranged to be open or closed, respectively, according as armature 36 is in its attracted or released position.

Armature supporting member 3! also carries at its opposite end a finger 40 to which is secured locking dog 32, the arrangement being such that when electromagnet L is deenergized, dog 32 rotates armature 35 counterclockwise (as viewed in Fig. 2) about trunnions 38 to a position away from cores 33 with the dog 32 being positioned in the path of shoulder 3|, but that when electromagnet L is energized, armature 36 is attracted toward cores 33 so that dog 32 is rotated clockwise about trunnions 38 to a position clear of the path of shoulder 3|. As will be made clear hereinafter, the movement of dog 32 to a position clear of shoulder 3| in response to energization of electromagnet L may be restricted at times by 00- operatin dog and segment elements providing the positive force-down features for the locking device, but such movement will be completed when the dog and segment elements are moved out of cooperating relationship. The cooperating dog and segment force-down elements as shown comprise a projection in the form of a lug or pin :34 provided on looking segment 30, and a cooperating depressor member 4| mounted on finger 48 and provided with a cammed surface adapted to engage and be driven underneath pin M. Depressor member 4| as shown (see Figs. 6 and 7) has a cam arm 45 carried at the lower end of a supporting leg 45a of member ll, and is beveled at one end so that when dog 32 is positioned clear of shoulder 3| (as shown in Figs. 6 and '7) movement of pin 44 past dog 32 will force the beveled surface of arm 45 downwardly to draw down dog 32 into the path of shoulder 3|. The parts are preferably so proportioned that when pin 44 rides on the upper horizontal surface of arm 45, dog 32 is forced down to approximately one-half of the depth of shoulder 3|. When dog 32 occupies its full down position (illustrated in Fig. 2) the doe. rests on the cut-away portion of segment 30 and the horizontal surface of arm 45 is then disposed underneath pin 44. With dog 32 in its full down position and member 4| and pin 44 in cooperating relationship any movement of dog 32 upwardly will be restricted by arm 45 engaging t ing: relationshipwith arm 45 or conversely rm 45is moved'out of 'cooperating'relationship with pin44.

The movement of pin -'44 with relation toarm '45 iseffected' in normal operation of the locking device, as will be'made clear hereinafter -while movement of arm-c with respect to pin 44-is-requiredfor emergency operation of the locking-deviceand in accordance with'my invention is attained'by pivoting-member'l on finger 6B, and by providing means operable to swing member-4 l to a' position where cam arm 45 is out of cooperating relationwith pin 44. Depressormember ll as "shown inFigs. 6 and '7'is slotted to'receive-finger 40 to which it is pivotall attachedbyapin-"M passing through aligned openings provided in finger 40 and' the-bifurcatedportion-of "member -41 As can be seen inFigp-fi; member 4 I is'pivoted eccentrically so that the weight of "the member causes it to be biased ina clockwisehirection about pin 42 with cam arm 45 normally occupying aposition in which'itis disposed for-cooperating relationship with-pin M. The bottom of the slot diagonally oppositepin-42 is-relieved at an angle (see Fig. 6) which permits member 4 l--toberotated counterclockwise about pin 42 to "a position in which arm *45 clears pin 44,-andin this position of member-4| the relieved bottom of the slot in member'4l will :bear against the bottom of 1 finger 46. --A pin '43, as shown in Figs. -6 and 7 preferably is pressed tightly-'into-an opening formed in member iiand rojects at an ang-le -to the axis'of-finge1' 40. Pin 43 is adapted-to cooperate with anoperating member of-an emergency release hereinafter described to :rotate member 4! about pin .42 to. a position in :which .arm 45 clears pin 44, and then subsequently-to lift 'finger 4|] so that dog 32lis withdrawn from 1 the path of shoulder 3 I.

.The emergency :release means provided 'for swinging member "4| about: its pivot 42- comprises a manually operabletpmnger E5 slidably'mounted in a supporting bracket 65 secured '.to .the rear of..face plate Iii with the plunger, projecting out- ;warclly through an opening formed in theiface plate. The plunger t.65:is'p1'ovided;at;itsouter end with a knob 68 and;istbiasedto"an outer- -most position as by. a coilspringifia confined' be- :rtween an upturned leg ofibracketziist-and a sprin-g :collar secured toiplungerfi5 asAby-LaLpin 'I-I. The portion of plunger 65 projectingoutwardly :from face plate l'0 is slotted adjacentlto-theface iplate to receivea thin ribbon 73 of metal which has its ends fastened togetheras by the=usua1 car seal. The sealed ribbon will 'functiomas-a 'telltale to indicate'that anoperation f plunger 65 has been efiected, and .will preventsuch an :operation until-the ribbon is broken and-removed from the slot to permit plunger -t5-toiibemoved :inwardly. iMember:65 carries at its extremein- -mally clear of pin 43 of depressor fiL-but'movable when plungerfiia is depressed to engage-..pin 43 to cause rotation of depressor member ik-about itszpivot pin 42 so that-cam arm 45is-oper-ated .clear of pin s l and the relievedportion of-the slot of member lllbears against finger 40 to force 1 that finger upwardly, thereby moving dog -32 entirely clear of shoulder 3iof segment 3il.

' The locking 'device alsois provided in the cus-' tomary mannerwith indication :means fo'r in'di- :cating the condition of locking imposed by :the :device upon the operation of shaft ll. 'Ihis means as shown-in Fig. 2-comprises-anarcuate ner end an operating member 12 disposed nor- *Visible through a window 5i provideci in -an opeii ing 53 formed-iniface plate l ll. Member -SO iS operated byan operatingro'd 54 fastened .to looking dog 32 with the arrangement being such that Whenlocking dog-321s in its'lowermostposition in locking'engagement with segment 30, arcuate member rotates to its lowermost-position but when locking-dog 32 -is operatede-to. or above the previously mentioned position in which the dog is withdrawn to one-halfof'the depth of shoulder 3l, rod' 54'drives member 50' to an upperposition in which a legend, such as Unlocked'fis visible through window 52. The pin' 5I about which member 50-rotates is supported by-a' member 55 which in turn is-supported from elements SB-secured to or'formed integrally on face-plate HI and disposed. on eitherside of dog 32 to provide restraining surfaces which prevent lateral movement of the dog.

The parts-of the locking device hereinbefore'de scribed are suitably enclosed by-a housing-6D formed to cover both sides, therear an'dthe'top 'of the deviceand provided with an opening 6! through'which a-staple 62fastened to face plate [0' projects to provide ahasp fora padlock (not shown) for' locking housing to= the other parts of "the lock device. The housing -60 when ren oved' provides access to the working parts of the locking device.

'The lock device hereinbefore described will operate in "the following 'manner: With handle i8 in its extreme left-hand position, asviewed 'in Fig. 1, the handle willbe retained-inthis position by the natural bias of the parts-including the weight of locking memberZlsupported from crank arm 24. In this position 'of theparts, looking member 21 is positioned in opening-'29 of lockable member 2 8 so that thispositionofhandle I8 corresponds to the locking condition of the device, and pin 44 carried by segmentfill is disposed immediately above but out of-engagement with cam arm 45 of depressor member-4i. With the parts in the positions described and electromagnetL deenergized; dog 32 will rest against the notched or cut-away portion of segment 30 so that the-dog is disposed inthe'path of movement of shoulder 3|, arcuatemember 50 will berotated Tasshown in Fig. 2 to its lowermost positionin which the legend Unlocked is obscured, while anotherlegend Locked maybe provided on the member-"50 to be visible in this condition of the apparatus, or as shown, the latter legend may be omitted from member 50 sothat no legendis visible at this time through the window.

I willnow assume that electromagnet L be- "comes energized'in response to current supplied "to-coils 34 over an energizing circuit (not'shown) When this happens, armature 36 is attracted toward pole pieces 33 to rotate armature-supporting -member3l about its trunnion screws 38, thereby causing dog 32 to lift away from the notched portion of segment 30. Upward movementof deg- 32 is restricted-howeverat this time since camarm -45 of depressor member-4i will engage pin44 carried "by segment 39. As previously-mentioned,

the parts of the indication means'areso-propor- This will indicate 'to the operator member 50 pivoted to rotate about--a pin i I and erationof h-andle W away from-its extreme lefthand position results in pin 44 moving to the lelt (as Viewed in Fig. 1) out of engagement with cam arm 45, thereby removing the restraint upon the upward movement of dog 32 so that armature 36 is attracted to its full down position to snap dog 32 out of the path of movement of shoulder 3|. This operation will take place immediately upon pin 44 disengaging from arm 45 and will result in dog 32 being lifted away from the path of shoulder 3| prior to the time that the shoulder reaches a position of engagement with dog 32, with the result that handle I 8 can be swung without interruption to its extreme right-hand position to cause operation of the contacts operated by the drum type controller and to lift locking member 21 out of opening 29 of lockable member 28. With handle l8 in its right-hand position, lockable member 28, is free to move so that this position of handle I8 corresponds to the unlocking condition of the device. The handle will be retained in this position by spring 63 engaging a notch 64 formed in the lower portion of segment 30 (see Fig. 1). It is, of course, obvious that if the operator should attempt to move handle |8 from its left-hand to its right hand position at a time that dog 32 is disposed in .the path of shoulder 3|, handle [8 will freely move toward its right-hand position until shoulder 3| abuts against locking dog 32 at which position further movement of handle I8 is prevented. The locking dog 32 and shoulder 3| therefore cooperate to prevent movement of handle i8 to its right-hand position unless dog 32 is withdrawn from the path of movement of shoulder 3| and dog 32 accordingly is positioned in locking relationship with segment 30, or is out of such looking relationship, according as the dog is or is not disposed in the path of shoulder 3 In this normal operation of handle I8 effective when dog 32 is operated by the associated dog operating mechanism, it is to be noted that the operator will not attempt to move handle l8 until after the Unlocked? indication is exhibited through window 52, and that after such indication is displayed handle |8 may be operated without interruption to its extreme right-hand position by the operator throwing the handle to its unlocking (right-hand) position. In order to unlock member 28, therefore, the operator is merely required to move handle 18 to its unlocking (right-hand) position after receiving the Unlocked" indication.

When handle I8 is operated to its right-hand or unlocking position, electromagnet L may be deenergized or not but in either case operation of handle l8 back to its left-hand locking position will result in dog 32 assuming its locking relatlonship with segment 3!]. Restoration of handle Hi to its left-hand position may be effected only when lockable member 28 is positioned so that looking member 21 can enter opening 29, and assuming that this condition obtains, handle l8 may then be restored to its left-hand position by the operator. If electromagnet L is deenergized at the time handle I8 is restored to its left-hand position, dog 32 will be resting against the upper portion of segment 30 so that when shoulder 3| moves past dog 32, the dog will drop down to rest against the cutaway portion of the segment and will be positioned for engaging shoulder 3|. If, however, electromagnet L is energized when handle I8 is restored to its left-hand position, or if with electromagnet L deenergized dog 32 should stick in its clear position, then dog 32 will not drop when shoulder 3| moves beyond the dog, but

the dog will be forced down into locking relation-.

ship with segment 3|) by pin 44 engaging cam arm 45 to drive that arm downwardly and under pin 44. This action will usually be suificient to correct any sticking action of dog 32 with electromagnet L deenergized and generally will result in such cases in dog 32 dropping to its full down position. In the case where electromagnet 'L is energized, however, the dog 32 will remain in its position half withdrawn from shoulder 3| established by arm 45 engaging pin 44, until electromagnet L becomes deenergized so that dog 32 drops to its full down position. The Unlocked" legend of member 50 will of course become obsoured when dog 32 operates to its full down position, and this will inform the operator that dog 32 is in looking relationship with segment 30.

Under the conditions just described operation of handle l8 from its locking to its unlocking position will be prevented at all times except when electromagnet L is energized, and it may be possible that operation of the handle is required at a time when the electromagnet L cannot be energized as, for example, due to some failure of the parts of its energizing circuit. Under these conditions the emergency release means embodying my invention provides means effective after operation to permit the operator to unlock member 28 merely by moving handle Hi to its unlocking (right-hand) position. Assuming that operation of handle l8 from its left-hand to its right-hand position is desired at a time when electromagnet L cannot be energized to operate locking dog 32, the operator will first break and remove ribbon I3 from the slot of plunger 65 so that the plunger is free to be moved inwardly. The operator will next depress plunger 65 to move operating rod 12 inwardly into engagement with pin 43 pressed into depressor member 4|. This will rotate member 4| about its pivot 42, arm 45 will be swung out of cooperating relationship with pin 44, and the relieved bottom of the slot in member 4| will bear against finger 40, thereby forcing the finger upwardly to drive dog 32 out of the path of shoulder 3|. The upward movement of dog 32 at this time will not be restrained by arm 45 engaging pin 44, consequently the dog 32 will be operated to its uppermost position in which armature 36 is swung into a position corresponding to its attracted position with respect to cores 33, and the armature and dog will therefore occcupy the positions corresponding to those established when electromagnet L is energized and pin 44 is moved clear of cam 45. This operation of dog 32 out of locking relationship with segment 30 will result in operation of member 58 by rod 54 so that the legend Unlocked is displayed through window 52. The operator will hold plunger 65 depressed, and will move handle i8 to its extreme right-hand unlocking position. Plunger 65 may now be released and when the operator does this, plunger 65 will operate to its outermost position in response to the bias of spring 69, and operating rod I2 will disengage from pin 43 so that member 4| will swing back to its biased normal position in which arm 45 is disposed for engaging pin 44 when handle I8 is restored to its locking position. Dog 32 will also drop into rest against the upper portion of segment 30 and the parts will therefore assume the condition which obtains when electromagnet L becomes deenergized after handle 3 is operated to its unlocking position with electromagnet L energized. With the parts in the condition described, the handle |8 may be restored to its left-hand position by the operator in the manner explained in detail hereinbe- 9 fore in connection with the. descriptionof the normal operation of the lockingdevice.

It is to be noted that the emergencyrelease means embodying myinvention-provides for unlocking member 28mere1y by operating handle l8 to its unlocking position after the Unlocked indication is displayedthroughwindow 52. The operation of-the locking device under emergency conditions of operation is therefore identical with the operation under normalconditions, in that in either case the operator will not attemptto move handle l8 until after an Unlock indicationis exhibited, and after such indicationis received the operator obtainsan unlock merely by moving handle l8 withoutinterrup-tion.to its right-hand position. In the-case of emergency operation, the Unlock indication is. provided by the operator depressingplungertE.to its extreme innermost position before actuating handle l8, so that a conditionis .establishedwhichis maintained by the operator without change while operating handle is to unlock member 28.

From the foregoing description it is readily apparent that I have provided an emergency release means effective to operate a lockingdog from its looking to itsunlooking position during the interval that a depressor member provided on'the locking dog is disposed in a position to engage a positive draw-down projection provided on the locking segment. The emergency release means is arranged to move the depressor-member out of the path of engagement with the-draw-down projection and then to. withdraw the locking dog from its locking position. The arrangement therefore provides means which makes it possible to incorporate both a positive draw-down of the locking dog and an emergency release in a locking device.

The emergency release means embodying my invention is highly advantageous for use with a locking device having positive force-down features for a locking dog, in that it provides the same type of operation of the operating member under both normal and emergency conditions of operation. The operator may therefore obtain an unlock merely by moving the operating member after receiving an Unlock indication, and therefore the emergency operation is exactly the same as normal operation, except for the usual depression of the emergency release plunger required to establish the emergency operation.

Although I have herein shown and described but one form of emergency release for locking devices embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, What I claim is:

1. In a locking device, in combination with a locking dog operable into and out'of locking engagement with an operating member movable between a first and a second extreme position only when said locking dog is out of its locking engagement, two cooperating elements comprising an element on said operating member and an element on said locking dog, said two elements being positioned in cooperating relationship in said first extreme position of said operating member with one of said two elements projecting into and obstructing the path traveled by the other element when said locking dog is. operated out of locking engagement with said operating member, and means for moving one of said two elements relative to the otherwhereby toremove said two elementsfromcooperating relationship and permit said-dog to be operated out of locking relationship. when said operating member occupies its. saidrfirst extreme position. I

2. In a locking device, .alocking .dog operable into and out of locking relationship with a'locking segment operablebetween a first and asec- 0nd extreme positiononly when said'locking dog is outoflocking relationship with said segment, two cooperating elements. comprising. a. fi'rstelement on .said locking segmentand a second element on saidlockingdog, said first element'being positioned in saidfirst extreme position-of said locking segmentto project into and obstruct the path traveled by saidfsecond element whensaid locking dog is operated. out of its said'locki'ng relationship, and means operable with said locking-segment stationary in its said first extreme position for moving oneofsaid. two elements relative to andcle'ar of the othernwh'ereby to permit said dog to be operated out of its said locking relationship, with said locking segment.

3. Ihe combination accordingto claim 2' in which said one element-movable relative to-the other is pivoted for rotation into and out ofoooperating. relationship/with said other element, and said' means for moving said: one element rotates said one element out of'cooperating relationship with. said otherelement.

4. The combination according to .claim 3; in whichsaid meansrotating'said one element out of cooperatingrelationship with saidfother element also eflects operation of 'said'locking dog out of locking relationship with said locking segment.

5. In a locking device, in combination with a locking segment movable between two extreme positions and a locking dog operable into and out of locking engagement with said locking segment for respectively preventing and permitting movement of said segment from one extreme position to the other, a projection on said segment, a cooperating depressor member pivotally connected with said locking dog and having a cammed surface adapted to be driven underneath said projection for drawing down said locking dog into locking engagement with said segment, and

means operable for rotating said depressor mem- 1 her out of cooperating relationship with said projection whereby to permit said locking dog to be forced out of locking engagement with said segment.

6. In a locking device, in combination with a locking segment movable between two extreme positions and a locking dog operable into and out of locking engagement with said locking segment for respectively preventing and permitting movement of said segment from one extreme position to the other, a projection on said segment, acooperating depressor member pivotally connected with said locking dog and having a cammed surface adapted to be driven underneath said projection for drawing down said locking dog into locking engagement with said segment, and means operable for rotating said depressor member out of cooperating relationship with said projection and for subsequently forcing said locking dog out of locking engagement with said segment.

7. In a locking device having means positively forcing down a locking dog which cooperates with a shoulder formed on a locking element operatively connected with an operating member for preventing movement of said operating member from a first to a second extreme position unless said locking dog is operated to a position clear of the path of movement of said shoulder; said force down means including a projection on said locking member for cooperating with means carried by said locking dog and effective in a given portion of the stroke of said operating member to draw down said locking dog into the path of movement of said shoulder, the

combination with such projection of cooperating means comprising a member pivotally mounted on said locking dog for rotation into and out of a position of engagement with said projection and biased into said engaging position, and means operable for rotating said member against its bias out of said engaging position to permit said locking dog to be forced clear of said shoul- 'der.

. 8. In a locking device, in combination with a locking segment movable between a first and a second position, and a locking dog operable into and out of locking engagement with said locking segment for respectively preventing and permitting movement of said segment from its said first to its said second position, a projection on said segment, a cooperating depressor member pivotally connected with said locking dog and biased to a position to engage said projection when said segment is moved into its said first position whereby a portion of said depressor member is driven beneath said projection in said first position of said segment, and means for rotating said depressor member clear of said projection to permit operation of said locking dog out of locking engagement with said segment in its said first position.

9. In a locking device, in combination with a locking segment movable between a first and a second position, and a locking dog operable into and out of locking engagement with said locking segment for respectively preventing and permitting movement of said segment from its said first to its said second position, a projection on said segment, a cooperating depressor member pivotally connected with said locking dog and biased to a position to engage said projection when said segment is moved into its said first position whereby a portion of said depressor member is driven beneath said projection in said first position of said segment, and means for rotating said depressor member clear of said projection and for operating said locking dog out of locking engagement with said segment in its said first position.

ISAIAH W. VENSEL.

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

' UNITED STATES PATENTS Number Name Date 1,710,668 Stephenson Apr. 23, 1929 2,390,815 Steiner Dec. 11, 1945 2,416,986 Field et a1 Mar. 4, 1947 2,437,328 McWhirter Mar. 9, 1948

Images