US2856028A

US2856028A - Automatic locking device

Info

Publication number: US2856028A
Application number: US363193A
Authority: US
Inventors: Racely Kermit Lamar
Original assignee: Dover Corp
Current assignee: Dover Corp
Priority date: 1953-06-22
Filing date: 1953-06-22
Publication date: 1958-10-14
Anticipated expiration: 1975-10-14

Description

Uct. M, l958 K. L. RACELY 2,856,028v v AUTOMATIC LOCKING DEVICE `0ct. M, 1958 K. L. RACELY 2,856,028

AUTOMATIC LOCKING DEVICE i JWM..

AUTMATHC LOCKDJG DEVICE Kermit Lamar Racely, Memphis, Tenn., assignor to Dover torporation, a corporation of Delaware Application .lune 22, 1953, Serial No. 363,193

9 Claims. (Cl. IS7-76) The present invention relates to an improved automatic locking device for elevatable platforms such as elevators, factory lifts, lumber lifts, loading docks, and the like, which are subject to heavy loads being trundled on and off the platform.

'In the following description and claims the term elevator is used in a generic sense as including elevators of all types, elevatable platforms, factory lifts, lumber lifts, loading docks, hoists, and the like, with which the automatic locking device of this invention may be equipped.

It has been found necessary in some elevator installations to provide additional supporting means for the elevator adjacent the oor or landing to prevent tipping of the elevator at the loading side while heavy loads are trundled on and olf. These locking devices usually comprise bolts movable into and out of locking position by manual or power means when the elevator has been moved to the proper position at the landing. In none of these prior installations, however, has it been possible for the supporting bolts automatically to be moved into locking position as the elevator approaches the landing, and to hold the elevator in proper or level position with rcspect to the landing. Furthermore, none of these prior devices incorporates any means automatically withdrawing the locking bolt when it is desired to lower the elevator from the elevated landing.

It is, therefore, the principal object of the present invention to provide a novel automatic elevator locking device which is movable into and out of locking or supporting position at the landing where it is desired to load or unload the elevator.

It is another object of the present invention to provide a novel automatic locking device for elevators which is moved into and out of locking position in accordance with the vertical movement of the elevator.

Another object of the present invention is to provide a novel automatic locking device for elevators which incorporates means which conditions the elevator control for movement of the elevator in a predetermined direction when it is desired to move the automatic locking device into nonsupporting position.

it is a further object of the present invention to provide a novel automatic locking device for elevators having simple controls which are readily incorporated into the now commercially used controls for either electric or hydraulically operated elevators.

A further object of the present invention is to provide a novel automatic locking device for elevators which does not require any manual controls for its operation other than those now used by the elevator operators.

Another object is to provide a novel automatic locking device for elevators which is simple in construction and incorporates a maximum of safety features so as to be certain in its operation.

Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawings, wherein:

Fig. l is an elevational view of the automatic lock- 2,856,028 Patented Oct. 14, 1958 ing device of the present invention, illustrating the landing support and a portion of an elevator in cross section, with the automatic locking device in its normal or nntripped position;

Fig. 2 is a view similar to Fig. l of the automatic locking device of the present invention, but showing the device in elevator supporting position;

Fig. 3 is an enlarged elevational view, partly broken into section, of the automatic locking device immediately prior to being tripped to release the locking bolt and diagrammatically showing the electrical control circuit and the elevator controls and operating mechanism;

Fig. 4 is a bottom plany view of the device as shown in Fig. 3, omitting the diagrammatic electrical circuit;

Fig. 5 is a transverse cross sectional view taken along the lines 5-5 of Fig. 3, looking in the direction of the arrows; and

Fig. 6 is a fragmentary elevational view similar to Fig. 3, showing a modified form of automatic locking device which is usable with elevators which may be stopped and supported at more than one elevated landing.

The construction of the elevator and the operating means and controls for raising and lowering the elevator and regulating its speed form no part of the present invention and for suitable operating mechanisms and controls reference may be had to Lawrence F. Jaseph Patents Nos. 2,280,291, dated April 2l, 1942, and entitled Power Transmitting System, and 2,553,045, dated May l5, 1951, and entitled Pump and Motor Hydraulic System.

The automatic locking device of this invention, indicated generally by the reference character lll, is shown mounted on the underside of an elevator l2 having a platform structure 14 and bottom frame i6, the locking device being `bolted to the bottom frame lo. The elevator 12 is vertically movable in a shaft 1S, or the like, a portion of which is shown in Figs. l-l, with Figs. l and 2 showing only an upper landing Zil to which it is desired to bring the platform 14 of the elevator in level position. If desired the shaft i8 may be provided with guide rails or ways for the elevator. It is preferred that the elevator be of the hydraulically operated type having electrical controls for the hydraulic operating mechanism, as illustrated in the previously mentioned patents.

The automatic locking device includes a locking bolt 22 adapted to engage in a steel lined recess 24 in the wall of the shaft 18, a guide cylinder 26 for the locking bolt 22, latching means 28 for holding the bolt in retracted position and releasing it at the proper time to engage in the recess 24, and electric control means 3l) which is integrated with the main control and operating mechanism 32 of the elevator l2, the latter being very diagrammatically shown in Fig. 3.

Preferably there are two locking devices mounted on the underside of the elevator platform lli at each active side or edge thereof to insure substantial stability of the elevator with respect to the landing 2l) and to provide an adequate safety factor for extremely heavy loads. Only one locking device is illustrated, it being understood that two or more may be used at properly spaced intervals at each active side of the elevator platform t4.

The locking bolt 22 comprises a bar 34 having a rectangular cross section and formed with a wide milled slot 36 at its outer end and opening to its upper side in which is journaled a roller 38 on a pin itl carried in the walls of the slot. The roller 38 projects slightly from the slot (Fig. 2) to be engageable with the wall of the shaft 18 and recess 24 for purposes which will be hereinafter explained.

At its opposite or inner end the bar 3ftis formed with a bore 42 into which projects a guide member or shaft 44, the outer end Vof which lis carried on a plate 461secured by means of bolts 48 to a supporting bracket 49 fixed with respect to and secured as by welding to the guide cylinder 26. Thus, the guide member or shaft 44 is fixed relative to the guide means 26 and the bolt bar 34 telescopes over the shaft 44.

The guide cylinder 26 comprises a pair of depending

plates

50, 52 welded to the underside of a top plate 54 by means of which the automatic locking device is secured by bolts 56 to the lower flange of the channel 16 and an extension plate 58. The

plates

50 and 52 are joined at their lower edges by a bottom cylinder plate 60 and the

plates

50, 52, 54 and 60 form the rectangular guide or cylinder 26 for the locking bolt 22. A pair of top and bottom machined ways 62, 64 are mounted within the guide cylinder 26 to insure freedom of movement of the bolt 22.

The locking bolt 22 is urged outwardly and toward the wall of the shaft 18 by a spring 66 confined between the inner end of the bolt bar 34 and rear plate 68 of the bracket 49, the plate 68 having a central opening 70 therethrough to accommodate the guide bolt 44 which is secured to the plate 46 to project inwardly of the bracket 49.

The latching means 28, which normally holds the bolt 22 in retracted position against the biasing force of the spring 66, includes a latch pin 70 carried fixedly in the bolt bar 34 to project sidewardly therefrom and outwardly through a longitudinally extending slot 72 in the cylinder plate 52. The outer end of the latch pin 70 is formed with right angled fiat working faces 74 and 76. retracted position of the bolt 22 the latch pin face 74 is engaged by a shoulder 7S on a latch hook 80 pivotally mounted by means of a stud 82 to the guide cylinder side plate 52, the latch lever being pivotal between the full and dotted line positions of Fig. 3. The latch hook 80 is formed with a straight flat edge 84 extending outwardly of the shoulder 74 to engage the latch pin face 76 when the latch bolt 22 projects outwardly of the guide cylinder 26 (Fig. 2) and while it is being reset to its retracted position. The latch hook 80 is biased in the clockwise direction and into engagement with the pin 70 by a tension spring 86 secured to an eyelet 88 on the lower edge of the latch hook outwardly of the pivot 82 and an eyelet 90 secured, as by welding, to the lower face of the plate 54.

The latch hook 80 is moved from latching position by a relatively wide latch tripping lever 92 pivotally mounted below the guide cylinder 26 on a pin or axle 96 projecting through a pair of depending ears 94 welded to the cylinder plate 60 and thc inner end of the lever 92. It will be observed from Figs. 1, 3 and 4 that the outer end of the latch tripping lever 92 projects outwardly of the elevator 12 and the guide cylinder 26 and toward the shaft wall 1S, so as to be in position to engage a tripping dog 98 lixedly mounted on the wall of the shaft 18 at a point slightly below the recess 24- and thereby to be pivoted downwardly or in the counterclockwise direction when the elevator rises past the dog 98. A link 100, pivotally mounted on a stud 102 projecting sidewardly from the latch hook 80 and by pin 104 to the latch tripping lever 92, communicates the counterclockwise movement of the latch tripping lever 92 to the latch hook 80 to draw the latter downwardly against the force of the spring 86, thereby releasing the latch pin 70 from the shoulder 78 and permitting the spring 66 to drive the locking bolt 22 outwardly against a steel plate 106 mounted in the wall of the shaft 18 immediately below the recess 24. The link 100 is formed with a slot 10S through which the pin 104 projects so that the tripping lever 92 has pivotal lost motion in the clockwise direction relative to the latch hook 80, thereby permitting the elevator to travel downwardly and the dog 9S clockwise to pivot the latch tripping lever 92 without releasing the automatic locking device.

The roller 38 at the outer end of thelocking bolt 22 In the rides on the plate 106 and prevents the bolt from binding against the shaft wall. After the lower edge of the bar rises above the lower edge 110 of the recess 24, the bolt is moved by the spring 66 into the recess, and the elevator 12 may, at least partially, be supported on the bolts 22 resting on the bottoms 110 of the recesses 24.

In order to lower the elevator 12 the locking device 10 must be reset, and the resetting means are shown in Figs. l and 2. The elevator 12 is first moved upwardly so that the roller 38 rides up and outwardly on the steel liner 112 of the recess 24 along an angularly disposed cam surface 114 which extends from the base of the recess to a point spaced from the shaft wall and very close to thc elevator. By the time the roller 3S reaches the straight and vertical surface 116 of the liner 112, the bolt bar 34 has been moved inwardly against the force of the spring 66 sufficiently to clear the locking pin 70 of the latch hook shoulder '78 which thereafter is in position to engage the locking pin face 74 as the locking bolt 22 is moved outwardly by the spring 66. The upward movement of the elevator 12 is but a few inches and not more than the distance between the bottom and top of the recess 24. As the elevator moves down and the roller 38 rides off the straight liner portion 116, the spring 66 moves the bolt 22 only slightly outwardly to engage the locking pin face 74 against the latch hook shoulder 78, and the resetting is then completed.

While it is possible that this resetting of the locking device 10 might be accomplished by first actuating the up control of the elevator so that the latter moves the requisite distance above the top landing, stopping the car, and then actuating the down control, it is not essential that this be done with the automatic locking device of this invention. Fig. 3 diagrammatically illustrates at 30 the additional circuit means to be integrated with the controls of the aforementioned patents which adapt these controls for use with an elevator equipped with the automatic locking device of this invention.

The operating and control mechanism for a hydraulic elevator of the type disclosed in the previously mentioned patents includes an expansible hydraulic motor secured to the elevator, a hydraulic pump, a hydraulic fiuid tank, an electric motor for the pump, valves, and electric controls, including relays, solenoids, and switches, for the electric motor and the valves. Since the herein invention is not concerned with the details of such apparatus, the whole is diagrammatically represented by a box and the reference character 32 in Pig. 3.

The electric circuit of the control system receives power from the line 118, 120. An up magnetic switch 122 which controls the current supply to the electric motor has one terminal connected to the line 113 and the other to a conductor 128. The line 113 is also connected to a down magnetic valve control 125 for the valve which controls the flow of hydraulic fluid from the expansible hydraulic motor back to the tank so that the downward movement of the elevator is properly governed. The usual controls also include a manually operable up switch 124 and a manually operable down switch 126, each of which has one of its poles connected directly to the line 120. The automatic locking device control ineludes a pair of two position switches 127 and 129 mounted on the underside of guide cylinder' 26 and bracket 49, respectively, by depending brackets 131 and lswitch 124, and line 120. When this circuit is energized, the operating and control mechanism 32 will move the elevator upwardly and the automatic locking device will be tripped adjacent the top landing as previously described.

The locking bolt bar 34, at its inner end, carries a switch operating member 14d projecting downwardly therefrom and through a slot 142 in the bottom of the bracket 49 and movable between retracted positions in which it is in actuating engagement with switch actuating arm 144 of the switch 129 and advanced position in which it is in actuating engagement with switch actuating arm 145 of the switch 127. When the locking bolt advances, the switch actuating member 140 releases the arm 144 and, since switch blade 148 is biased to close the contacts 134, it moves in such direction to close the contacts 134 and simultaneously open a pair of contacts 150. Almost immediately the member 1411 contacts and moves the arm 145 of switch '127 to move the switch blade 136 from its biased position, closing the contacts 13G, to open the latter and close a pair of contacts 146.

The

switches

127 and 129 are preferably of the biased snap acting type and are so adjusted that the movement 0f the member 140 substantially to the full extent of its travel in either direction is required to operate them so that there will be no malfunctioning of the control circuit 30.

The second terminal of the magnetic valve control 125 is connected by a conductor 154 to one of the switch contacts 150, and to a conductor 156 leading to one of the switch contacts 146.' The second contact 150 andthe second `Contact 134 are connected together and by a conductor 158 to that pole of the down7 switch 126 opposite the line 12%. Therefore, when the locking bolt 22 has been seated in the recess 2d and the actuated arm 145 has opened the switch contacts 130 and closed the switch contacts 146, and the released arm 1441 has opened the switch contacts 150 and closed the switch contacts 134, the circuit 3i) throughfthe automatic locking device has been conditioned for down operation.

Closing the up switch 124 completes a circuit from the line 120 through the conductor 138, the normally closed contacts 130 of the switch 127, the conductor 128, and the up magnetic switch 122 to the line 118, thus energizing the pumping unit for upward motion of the elevator. When the elevator` with its safety device reaches the tripping dog 98, the locking mechanism will be tripped as .previously described and the bolt 22 urged forwardly as far yas the plate 1116 permits, but not far enough to operate the switch 127; therefore, the upward motion of the elevator continues. When the bolt enters the recess 24, however, the switch 127 is actuated, thereby interrupting the circuit to the up magnetic switch 122. At this time, due to the inertia of the driving parts in the hydraulic pumping unit, the elevator will be somewhat above its landing 2d, but if the up switch 124 is held in closed position, a new circuit through the now closed contacts 146 of the operated switch 127, conductor 156, and down magnetic valve control 125 is completed, causing downward motion of the elevator until its weight is taken yby the locking bolts 22 resting on the ledges 110 of the recess 24 in the hatch walls. The operator will normally release the up button or control at this time, leaving the elevator securely seated on the safety device.

Closing the down switch 126 establishes a circuit through lthe line 126, down switch 126, conductor 158, contacts 134 and switch blade 146, conductor 132, up magnet switch 122, and the line 116.` Because a circuit through the up magnetic switch is energized, the elevator 12 will be moved iirst in the upward direction despite the fact that the down button has been pushed. This upward travel will continue until theV cam surfaces 114, 116 move the locking -bolt 22 against the spring 66 sufciently so that the latch hook 80 engages the pin 70, at which time the switch operating member 140 will have moved away from the arm 145 and actuated the arm V144,v therebyrestoring the

switches

127 and 129 to the positions in which they are shown in Fig. '3. The circuit through the up magnetic switch 122 will be opened, but another circuit 'through the down switch will be closed as follows: line 120, down switch 126, conductor 158, switch contacts 159 and switch blade 16g, conductor 154, down magnetic valve control 125, and line 118. This establishes the circuit necessary to open the valve governing the descent of the elevator and it moves downwardly at a rate regulated by the control mechanism andv system 32.

As `the latch tripping lever 92 contacts the stationary tripping .dog 98, the diagonal surfaces on these members engage and slide over each other, the lever 92 pivoting in the clockwise direction and the pin 1154 moving in the lost motion slot 108 in the link 1011 so that the latch hook is not moved. Thus, the elevator can travel downwardly completely automatically, and with normal operation of the usual manual controls even though the locking bolt must first Ibe disengaged from the recess 211.

It'should be appreciated that the operation of this automatic locking device is very simple and requires no more manipulation by the operator of the elevator 12 than required at present, it being `one of the advantages of the presentinvention that the locking device is completely automatic, requiring no special manual controls. Also it will be seen that slight upward movement of the elevator before its descent easily 4releases the locking bolt from the recess, which minimizes the amount of wear to which this part is subject.

The described automatic locking device is contemplated for use with a single landing. However, it may be used with more than vone landing and a modification of the locking device of this invention for use with a plurality of landings iswshown in Fig. 6, wherein those elements which are similar to and fully equivalent to the comparable elements of the principal modification shown in Figs. 1 to 5 are designated by the same reference number with the suffix LL In this modification the latch tripping lever 92a is slotted at 160 where it is pivotally mounted on the pin 96a carried inthe depending ears 94a. The inner end of the lever 92a is provided with an ear 162 received between bifurcated ends 164 of a solenoid armature 166 and pivotally secured thereto by a pin 16S. The armature 166 is carried in a solenoid 170 mounted on the bracket 131a opposite the switch 127a and is biased outwardly by a spring 174 secured between the inner end of the armature 166 and the bracket 131g. The solenoid has one of its poles connected to the line 126:1 and its other pole connected by a conductor 176 to one terminal of a manually operable switch 178, the other terminal of which is connected by a conductor 180 to the line 118a.

If it is desired to operate the elevator to the rst landing, then the operation is carried out in the manner previously described and the up switch 124e is closed. However, if itis desired to operate the elevator to any landing above the rst landing, then the switch 178 is manually closed as well as the switch 124a. This energizes the solenoid to retract the armature 166 against the force of the biasing spring 174. The armature 166 pulls the trip lever 92a inwardly, the amount of movement being governed by the length of the slot 160 but being suilicient so that the lever 92a in its retracted position will clear any of the stationary trip lugs 98o which normally lie in its path. This retracted movement of the lever 92a utilizes the lost motion connection between the link 100a and the lever 92a as the pin 10aa moves very slightly upwardly in the slot 108m As the elevator approaches the landing at which it is desired to stop, the switch 178 is opened, deenergizing the solenoid 170 and the spring 174 moves the armature 166 outwardly thereby restoring the trip lever 92a to tripping position, and the latter engages the stationary trip dog 98a to operate the automatic locking device in the manner previously described herein.

From the foregoing description it will be clear that the objects claimed for this invention are fully attainable by the structure illustrated which is simple in its construction, extremely rugged so as to support the load to which it will be subject, and simple in its operation so that the elevator operators who are familiar with conventional controls need learn no new operations for an elevator equipped with the device of this invention.

While two embodiments of the automatic locking device constituting the invention have been shown and described, it will be apparent that numerous modifications and variations thereof may be made without departing from the underlying principles of the invention. It is therefore desired, by the following claims, to include within the scope of the invention all such variations and modifications by which substantially the results of this invention may be obtained through the use of substantially the same or equivalent means.

What is claimed as new and desired to be secured by United States Letters Patent is:

l. An automatic locking device for an elevator or the like including in combination, a reciprocable locking member mounted on the elevator and adapted in one position to engage a stationary supporting means, means biasing said locking member to such position, a pivotally mounted latch releasably connected to said locking member to hold the latter against movement by said biasing means, means releasing said latch from holding position upon movement of the elevator in a predetermined direction, said last named means including a pivotally mounted trip lever engageable with a xed trip member as the elevator moves in said predetermined direction toward said supporting means and a link interconnecting said latch and said trip lever, and means engageable by said locking member to cause said locking member to be engaged by said latch upon further movement of the elevator in said predetermined direction. v

2. An automatic locking device for an elevator or the like having electric control means including in combination, a movable locking member mounted on the elevator and movable in a rst direction to engage a stationary supporting means, means biasing said locking member in such direction, releasable latch means holding said locking member against movement by said biasing means, trip means transitorily engageable by said latch means to release the latter from holding position upon move-' ment of the platform in a predetermined direction toward the position in which said locking member may engageV said supporting means, cam means engageable by said locking member upon further movement of the elevator in the predetermined direction to reset said locking member, and switch means in said electric control means and actuated by said locking member upon movement thereof to condition said electric control means for operation of the elevator in desired directions and in such direction as to reset said locking member. i

3. An automatic locking device for an elevator or the like having an electric control means including manually operable Up and Down controls comprising in combination a reciprocable locking member mounted on the elevator and adapted in an advanced position to engage a stationary supporting means, means biasing said locking member to said advanced position, releasable means holding said locking member in a retracted position and against movement by said biasing means, stationary trip means engageable with a part of said releasable holding means as the elevator moves upwardly toward said stationary supporting means to actuate said releasable holding means to permit said biasing means to move said locking member to said advanced position, cam means engageable by said locking member upon further upward movement of the elevator to move said locking member to said retracted position to be held therein by said re-` leasable holding means, and a pair of switches in the electric contro1 means, said switches being positionedto be actuated by said locking member in said advancedy and retracted positions, whereby actuation of the Down control with said locking member in said advanced position causes the elevator first to rise to retract said locking member and actuate one of said switches and then causes the electric control means to lower the elevator.

4. An automatic locking device for supporting an elevator or the like at a landing including in combination, a pocket in the landing support and adjacent the landing, a locking bolt slidably mounted on the elevator and movable between a retracted position and an advanced position in which the outer end of said locking bolt may engage in and be supported from below by said pocket thereby to support the elevator, spring means biasing said locking bolt toward said advanced position, a pivotally mounted latch engageable with said locking bolt and biased in such direction as to hold said locking bolt in said retracted position, a pivotally mounted latch tripping lever, a link pivotally connected to said latch and 'to said latch tripping lever and having a lost motion connection with said latch tripping lever, whereby pivotal movement of said latch tripping lever in one direction disengages said latch from said locking bolt to release the latter and said latch tripping lever may be pivoted in a second direction relative to said latch, and trip means carried by the landing support adjacent said pocket and in the path of vertical movement of said latch tripping lever to pivot the latter in said one direction as the elevator is raised and in said second direction as the elevator is lowered therepast,

5. An automatic locking device for supporting an elevator or the like at a landing including in combination, a pocket in the landing support and adjacent the landing, a locking bolt having a roller journaled in its outer end slidably mounted on the elevator and movable between a retracted position and an advanced position in which the outer end of said locking bolt may engage in and be supported from below by said pocket thereby the support the elevator, spring means biasing said locking bolt toward said advanced position, a pivoted latch engageable with said locking bolt and biased in such direction as to hold said locking bolt in said retracted position, a latch tripping lever connected to said latch and movable in such direction as to disengage said latch from said locking bolt to release the latter, and means carried by the landing support adjacent said pocket and in the path of movement of said latch tripping lever to move the latter in latch disengaging direction as the elevator is raised, and cam means mounted on the landing support above said pocket and engageable by said roller upon further upward movement of the elevator to move said locking bolt to retracted position thereby reengage said latch with said locking bolt.

6. An automatic locking device for supporting an elevator or the like at a landing including in combination, a pocket in the landing support and -adjacent the landing, a locking bolt having a roller journaled in its outer end slidably mounted on the elevator and movable between a retracted position and an advanced position in which the outer end of said locking bolt may engage in and be supported from below by said pocket, spring means biasing said locking bolt toward said advanced position, a pivotally mounted latch engageable with said locking bolt and biased in such direction as to hold said locking bolt in said retracted position, a pivotally mounted latch tripping lever a link pivotally connected to said latch and to said latch tripping lever and having a pivotally mounted lost motion connection with said latch tripping lever, whereby pivotal movement of said latch tripping lever in one direction disengages said latch from said locking bolt to release the latter and said latch tripping lever may be pivoted in a second direction relative to said latch, means carried by the landing support adjacent said pocket and in the path of vertical movement of said latch tripping lever to pivot the latter in said one direction the elevator is lowered therepast, and cam means mounted on the landing support above said pocket and engageable by said roller upon further upward movement of the elevator to move said locking bolt to retracted position thereby to reengage said latch with said locking bolt.

7. An automatic locking device for supporting an elevator or the like having a control system, including in combination, a locking bolt mounted on the elevator and movable to one position in which it engages a stationary supporting means thereby to support the elevator, means biasing said locking bolt to such position, latch means holding said locking bolt in a second and retracted position and against movement by said biasing means, means releasing said latch means from holding said locking bolt upon movement of the elevator in a predetermined direction so that said locking bolt may engage said supporting means, and electric circuit means in said control system including a pair of circuit conditioning switch means alternately actuated by said locking bolt at the opposite ends of its movements to said positions to permit operation of the elevator in desired directions, and manually operable switch means connected to said pair of switch means and selectively operable to cause movement of the elevator in a selected direction after retraction of said locking bolt to said second position.

8. An automatic locking device for supporting an elevator or the like at a landing, the elevator having electric control means, including in combination, a movable locking member mounted on the elevator and adapted in one position to engage a stationary supporting means thereby to support the elevator, means biasing said locking member to such position, releasable means holding said locking member in a second and retracted position and against movement by said biasing means, a pair of electric control conditioning switch means in said electric control means and alternately actuated by said member as it moves into said positions to condition said electric control means for operation of the elevator in desired directions, and manually operable switch means connected to said pair of switch means and selectively operable to energize said electric 10 control means to cause movement of the elevator in a selected direction after retraction of said locking member to said second position.

9. An automatic locking device for an elevator or the like having a control system, including in combination, a reciprocable locking member mounted on the elevator and projectable to engage a stationary supporting means thereby to support the elevator, means biasing said locking member in the projected direction, a releasable latch means holding said locking member in a retracted position against movement by said biasing means, a trip lever, a lost motion connection pivotally mounting said lever to the elevator, a link having a lost motion connection With said trip lever connecting said trip lever with said releasable latch means, trip means engageable by and moving said trip lever as the elevator moves toward a landing thereby to move said latch means from holding position to release said locking member for projection into engagement with said supporting means, electromagnetic means in said control system having a movable part connected to said trip lever for withdrawing said trip lever upon energization of said electromagnetic means so that said trip lever will be moved out of the path of engagement with said trip means as said trip lever moves therepast, and manually operable switch means in said control system connected to said electromagnetic means for selectively energizing the latter.

References Cited in the le of this patent UNITED STATES PATENTS 1,302,873 Stii May 6, 1919 1,773,163 Becker Aug. 19, 1930 2,597,056 Beder May 20, 1952 2,639,150 Aberle May 19, 1953 FOREIGN PATENTS 222,720 Germany June 4, 1910 743,208 France Jan. 6, 1933