US2091156A - Lift structure - Google Patents

Description

D. D. MYERS Aug. 24, 1937.

LIFT STRUCTURE Filed Jan. 20, 1936 5. Sheets-Sheet l c2193? gm Aug. 24, 1937. D D MYERS 2,091,156

LIFT STRUCTURE Filed Jan. 20', 1936 3 Sheets-Sheet 2 n .1 I l Aug. 24, 1937. D. D. MYERS 2,091,156

LIFT STRUCTURE v Filed Jan. 20, 1936 3 Sheets-Sheet 3 Patented Aug. 24, 1937 UN'HTE FATENT OFFICE LIFT STRUCTURE poration of Ohio Application `lfanuary 20, 1936, Seriai No. 59,934

23 Claims.

An object of my invention is to provide a lift structure of comparatively simple and inexpensive construction, the present application being an improvement over my copending applications Serial Number 39,939 led September 10, 1935 and Serial Number 47,137 iiled October 28, 1935.

A further object is to provide a lift structure with a combination manual and automatic switch which automatically limits the movement of the carriage, so that its movement is not excessively high or excessively low, which would result in breakage of parts.

A further object is to provide a control structure which can be manually moved to operating position and to non-operating position ii, desired, automatic means being provided to move it to nOnoperating position at its limits of travel.

Another object is to provide a switch structure which is manually operable to cause moven ment of a vehicle lift or the like upwardly or downwardly, a guard means being utilized, however, to prevent movement of the switch to up position when it has reached its set limit of upward movement, or to down position when it has reached its set limit of downward movement.

Still a further object is to provide in a type oi lift having a post relative to which a carriage moves vertically, a shield for at least partially fm enclosing the post for protecting operative parts otherwise exposed in the post, the shield being of telescopic character to prevent prohibitive extension thereof when the lifting carriage reaches its upward limit of movement.

Another object is to provide a shield in the form of. an assembly, consisting of a plurality of telescoping sheet metal elements, means being provided to limit their extension both relative to each other and relative to a post on which they 4 4) are mounted, one of the elements being connected with the lifting carriage to insure proper extension and collapse of the shield during lowering and raising of the lifting carriage.

A further object is to provide axle blocks for the lifting rails of vehicle lift, these blocks being so formed that they can be readily removed from the rails of the lift without sliding them orf the ends thereof by merely tilting and twisting them, whereupon they may be removed, the

,7U blocks, however, being so formed that normally they cannot move laterally relative to the rails, although they can be moved longitudinally thereof.

A further object is to provide in connection with one form of axle block, a hook-like handle adapted to engage the rail under tension to retain the axle block in adjusted position.

Another object is to provide a pair of axle blocks connected for simultaneous sliding movement and actuation to position permitting re- 5 moval of both blocks simultaneously from the lifting rails.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which:

Figure 1 is a perspective view of a lift structure or" the four post type, embodying my invention.

Figure 2 is a greatly enlarged front elevation of a control switch mounted on one of the posts.

Figure 3 is a side elevation in the direction of the arrow 3, adjacent Figure 2, parts of the gure being taken on the section line 3 3.

Figure l is a plan view of the switch structure showing the post on which it is mounted in cross section. 25

Figure 5 is a sectional view on the line 5--5 of Figure 2.

Figure 6 is a sectional view on the line 6 6 or" Figure 4, showing the switch in an operating position.

Figure 'l is a similar view showing it in nonoperating position.

Figure S is an enlarged perspective View of the nearest corner post in Figure 1, showing most of the post broken away and illustrating a shield assembly comprising a plurality of telescoping elements.

Figure 9 is a similar perspective View of the far corner post of Figure l, showing the shield co1- lapsed. 40

Figure 10 is a sectional view on the line I-IIJ of Figure 8.

Figure 11 is a perspective view of vehicle supporting rails of the lift, showing axle blocks mounted thereon.

Figure 12 is a sectional view on the line |2-I2 of Figure 11, showing one of the axle blocks in end elevation.

Figure 13 is a side elevation of the axle block shown in Figure 12.

Figure 14 is a bottom plan view thereof.

Figure 15 is a top plan view of the same.

Figure 16 is a top plan view of the axle blocks at the inner ends of the rails in Figure 11.

Figure 17 is a sectional View on the line I'I-I'I of Figure 16.

Figure 18 is a sectional view on the line I8-I8 of Figure 16; and

Figures 19 and 2O are sectional views on the lines i-IS and E-Z respectively of Figure 18.

On the accompanying drawings, I have used the reference numeral I I) to indicate a corner post of a lift structure. I have illustrated four of these corner posts, and a carriage vertically movable relative thereto, consisting of vehicle supporting rails I2 and end rails I4. The ends of the end rails I4 are provided with bearings I6 which extend to a position between the anges I' of the posts I9, the posts Ill being angle shaped in cross section as shown in Figures 8 and 10.

The lifting carriage is motivated by an electric motor I8 which rotates sprocket nuts relative to stationary screws 2Q, as shown in my copending applications. The sprockets carry the vehicle supporting rails I2 upwardly or downwardly as desired. My present application is not concerned with the particular means actuating the carriage but rather with details of construction, which I will now describe.

In association with the motor I8 I provide a reversing switch 22 of any suitable type, having a control knob 24 manually movable from 01T to either up or down positions, or vice versa, as will hereinafter appear. Ihe switch is, of course, connected with a suitable source of current supply and by a flexible conductor 25 with the motor I8.

It is desirable, of course, to automatically control the switch 22 to limit the upward and downward movement of the lifting carriage, so that the carriage will not overrun these limits, and thereby cause breakage of parts of the lift. For this purpose I provide a cam member comprising a sliding plate 28 carrying a pair of oppositely inclined cams 30 and 32 for cooperation with the control knob 2li. The cams 33 and 32 are secured to the plate 28, and are provided with an ear 34, (see Figure 2) to which a control rod 36 r is secured. The control rod extends slidably through a bracket 38 on the post I, and is provided with a pair of collars lil and 42. These collars are adapted for engagement by an arm M extending from a special casting Ia of the lift carriage on which the motor I8 is mounted. A third collar 46 is provided for limiting excessive upward movement of the rod 3B.

The plate 23 is slidable relative to the switch casing, it being confined between the back thereof and two pairs of posts it extending from the back and connected by a cross bar Sil, the cross bar being bolted as at 52 to the post IG (see Fig ure A leaf spring 54 (see Figure 3) is secured to one of the cross bars 5I), and frictienally engages the plate 28 to normally hold it in any position to which it is moved.

The cam 3Q is inclined upwardly and toward the post IQ, as shown in solid lines in Figure 3, while the cam 32 is inclined upwardly and away from the post as shown by dotted lines. These cams are adapted to engage the knob 2f?- when it is in either its up or down position. In Figure 2 the carriage is illustrated at its lower limit of movement, the arm 435i having engaged the collar 40 and moved it downwardly, and consequently the cams 3H and 32 downwardly to the position shown in Figure 2.

Pivoted to the cam 32 is a guard 5S, the pivot connection being indicated at 58. This guard, due to its weight, assumes the position shown in Figure 3, a portion thereof being dotted as it extends behind the switch 22. It will be noted that this guard is in such position that it will not permit movement of the knob 2li from off to down position, thus guarding against actuating the motor I8 in a downward direction when it is already at its downward limit of movement.

With the cams Si] and 32 in the position shown in Figure 2, it is possible, however, to move the knob 24 from on te up position as illustrated, the cam 3i) being in such position (see Figure 3) that it does not interfere with such movement. The cam 3E! has pivoted thereto a second guard means SEI, the pivot being shown at 62. A counter-weight 64 extends from the guard GI) normally tending to keep it in the i'ull line position of Figure 3. This guard, it will be noted, is not in position to intereere with movement of the knob 2li from oit to up position.

With the parts in the position or Figure 2, the motor I8 is actuated for raising the lift carriage, and the arm M will consequently move from the collar i9 and at the upper limit of movement raise the collar ft2, and consequently the cams 30 and 32 together with the guards 55 and Gil.

Referring to Figure 3, the guard Sel can tip to the dotted position relative to the cam 3Q, and will do so as the cam rises and the upper edge oi' the guard strikes the knob 26. The cam will swing the knob toward the off position, and such movement will be continued by mechanism within the switch,such as a roller and cam mechanism shown in Figures 6 and '1.

In the up or "down position of the switch, a roller G6 engages in a notch 63 of a cam l0. The roller is carried by a pivoted arm 'It A spring "I2, connected with the arm, causes such engagement. Adjacent each notch Sii a hump '59 is provided beyond which a center notch ill for the ori position is provided. Accordingly the knob 2li can be rotated slightly so that the cam 'I5 assumes the dotted position in Figure 6, after which the knob swings the rest of the way to the ofi position.

Thus by starting the knob from up toward oi position by the cam 3G, it will continue its swing until the off position is assumed. By that time the carriage will have lifted far enough to move the cam 3U to the dash line position shown in Figure 3, the guard E@ will swing, shown by dot and dash lines, to a level though higher position. When in this position, the guard Gil will prevent movement of the knob 2li from oil to up position, but the guard 56 will be above the knob, thus permitting it to be moved to the down position only.

In Figures 8, 9 and 10 I show a shield for the post Il) comprising a plurality of telescoping elements It, I8, 89 and 82. These are provided for closing the open side of the angle shaped post lil, as best shown in Figures 9 and l0. The elements 76, '13, im and 82 provide a shield assembly which is preferably closed at the top by a cap 8G. The post I@ is also provided with a cap Means is provided for limiting the extension oi one element relative to the other, so that they do not become dissociated, and this means consists of strips 83 secured at the tops of the elements 1S, 8@ and 82 and extending downwardly inside the elements, these strips terminating in hooks Si). At the top of the next nearest element a cooperating hook 92 is provided. When the telescoping elements are collapsed, the hooks 92 and Si? are spaced substantially from each other, indicated in Figure 8, adjacent the lower end tion on the rail.

of the assembly, while when the elements are extended, the hooks cooperate with each other, the upper two in Figure 8 being close tothe cooperating position.

The lowermost element I6 is provided with a hook 94 for engagement with a cooperating hook 96 secured to the carriage bearing I6. The upper strip 88 is provided with a lug S8 for engagement under the cap 86 of the post I0.

In associating the shield assembly with the post I0, the parts are telescopically associated, and this assembly is then pla-ced on the post by extending the assembly and slipping it down over the post, while the carriage is in lowered position. First of all, the lug 9.8 will engage the cap 8S of the post, and the upper strip 88 is then sprung outwardly until the lug passes the cap, so that it can thereafter engage the under side of the cap.

The shield is then lowered until the hook 94 engages the hook 06, whereupon the hook 94 is forced past the hook 96, so that they can thereafter cooperate in such manner that when the carriage lowers, it will lower the shield element 1B. This insures proper extension of the shield assembly as the lift lowers, as friction between the telescoping elements might be too great to be overcome by the weight of the elements. As the carriage raises, the telescoping elements will be collapsed, and the upper element 82 can raise relative to the top of the post I0, so that the cap 84 is spaced from the cap 80, as shown in Figure 8, the lug 9S preventing any further spacing of the caps relative to each other. When the carriage is in lowered position, the cap 84 lowers to position adjacent to the cap 86.

On the vehicle supporting rails I2 I provide axle blocks 00 and |02 The blocks |00 are for the rear axle of the automobile, notches |04 being provided therein for the axle, and a notch |06 being provided for the truss rod, if any, of the axle. Each axle block |00 rests on top of the rail I2, and is provided with guide means for flanges |08 to normally prevent lateral movement of the block |00 relative to the rail.

At the lower ends of the flanges |08 I provide inwardly directed flanges I I0 and I2, which are diagonally oppositely arranged as shown in Figure 14. This construction permits tipping of the block |04, as shown in Figure 13, so that the flanges |08 clear the tops of the rails I2, and the block may then be twisted as shown by dotted lines in Figure 14, so that the flanges II 0 and I I2 clear the sides of -the rail, whereupon the axle block can be lifted off the rail without the necessity of sliding it off the end thereof.

For manipulating the axle block |00 as described, I provide a handle ||4 terminating in a hook IIS. The normal position of the handle and hook relative to the block is shown by dotted lines in Figure 12.

The rod II 4 is formed of spring steel or the like, and can therefore be sprung to the position shown in Figure l2, thus placing the handle under tension when the hook IIS is engaged over the edge of the rail I2, as shown by solid lines. This retains the block effectively downward against the rail I2, and normally prevents tipping thereof, as shown in Figure 13, so that the operator is thus insured of the axle block remaining in posi- This also insures maintaining the position of the block longitudinally of the rail, the handle I|4 facilitating such movement for adjusting the block to the vehicle without having to get under the rear end of the chassis.

The blocks |02 are provided for the front axle of the vehicle and are preferably connected by bars IIB. These in turn are provided with a handle |20 for manipulating the blocks |02. The blocks |02, in a somewhat similar manner to the blocks |00, are provided with diagonally oppositely disposed flanges Illia and II2a, and also with anges I08ct. The blocks |02 can be oper-ated in a similar manner for disconnection from the rails I2. These blocks, however, are simultaneously operable by the handle |20 and the bars I I8.

The bars II8 are slidably received in sockets |22 of the blocks |02. These sockets are open at their bottom, as shown in Figure 20, so that the bars I I8 rest directly on the rails I2. This serves as a reinforcement for the blocks |02, on which the axles of the vehicles rest, these blocks being usually formed of cast iron.

In manipulating the blocks |02 to disconnect them from the rails I2, the handle |20 is rst lifted to tip the blocks |02 in the manner similar to that shown in Figure 3, tc cause the iiangesv Ia to clear the sides of the rails I2. The handle |20 is then swung in the direction of the arrow |24, to release the flanges lilla and |I2ay from under the rails I2.

During this swinging operation, the blocks |02 will move away from each other as vthey are farther spaced when mounted diagonally on the r-ails I2 than when mounted at right angles crosswise thereof. The sliding connection of the bars I I8 in the sockets |20 permits such movement of the blocks away from each other. After the blocks have been sufliciently twisted to clear the flanges Illia and |1201., the blocks may be simultaneously lifted off the rails I2.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

1. In a lift structure, a lift carriage, means for motivating said carriage, posts for guiding said lift carriage vertically, a controller for said motivating means and an automatic control element therefor movable relative to each other, said controller being mounted on one of said posts, said automatic control element being operably connected with said carriage for movement thereby, said controller having a manually operable control element movable laterally of said posts, a pair of guard means each pivoted to said automatic control element, one of said guard means to prevent movement of said manually operable control element to operating position when said automatic control element has been moved to one of its positions by said carriage and the other to prevent movement of said manually operable control element to operating position when said automatic control element has been moved to the other of its positions by said carriage, said controller being moved to inoperative position and said guard elements moving to non-guarding position upon said automatic control element being moved to either of its positions by said carriage, said guard elements thereafter returning to guarding position.

2. In a lift structure, a lift carriage, means for motivating said carriage, a post for guiding said carriage vertically, a controller for said motivating means, an automatic control element moved by said carriage at opposite ends of its travel, said controller having a manually operable control element, said automatic control element having cam surfaces to engage said manually operable control element and thereby move said controller to inoperative position upon said automatic control element being moved to either oi its positions by said carriage.

3. In a lift structure, a lift carriage, motivating means therefor, a post for guiding said lift carriage vertically, a controller for said motivating means mounted on said post, a control lever on said controller manually movable laterally of said post to operating position, and means for automatically moving said controller to inoperative position comprising a cam vertically movable relative to said post, means operated by said carriage at opposite limits oi vertical movement to move said cam vertically, said cam moving said control lever` when in operating position laterally to non-operating position,

4. In a lift structure, a lift carriage, a motivatmeans therefor, a post for guiding said liit ri ge vertically, a controller lor said motivating means mounted on said post, a control lever on said controller manually movable laterally of said post to operating position, and means for automatically moving said controller to inoperative position comprising a cam vertically movable relative to said post, means operated by said carriage at opposite limits oi vertical movement to move said cam vertically, said cam moving said control lever when in operating position laterally to non-operating position, and guard means carried by said cam and movable to position preventing movement of said control lever to operating position except for causing movement oi carriage in a direction opposite to its previous direction of movement.

fi. In a liit structure, a post, a lift carriage movable vertically relative thereto and guide-fl thereby, an electric motor carried by said carriage, a switch mounted on said post, a exible electric connection between said switch and motor. and means for automatically controlling said switch comprising a cam vertically movable on said post and operated to opposite positions by said carriage at opposite limits of its movement, said switch having a control element manualiy operable to cause ascension and descension oi said carriage relative to said post, said cam cooperating with said control element to move it to open circuit position at opposite limits of travel of the carriage, and means carried by said cani for preventing manual movement of said control eieinent to ascension position when the carriage is at its upper limit of travel, and to descension position when the carriage is at its lower limit of movement.

6. In a lift structure, a carriage, a post for gudii'ig the movement of said carriage, and a sh .ld for the portion of said post on one side of .said carriage comprising an assembly consisting of a plurality of telescoping elements which at least partially surround said post, means for limiting the extension of said elements relative to each other, means on the element at one end of said assembly to engage said post to prevent disassociation of said clement relative to said post, and means on the element at the other end of assembly to engage said carriage for extendM lng and collapsing said assembly as said carriage moves toward or away from the end of said post on side of said carriage, said last two means comprising hooks which can be sprung to non-interengaging position to permit said assembly to be removed from said post.

7. In a liit structure, a lift carriage, an angle shaped post for vertically guiding said carriage, and a shield for a portion of said post above said carriage comprising an assembly consisting of a plurality of telescoping elements closing the open side of said angle shaped post, means for limiting extension of said elements relative to each other comprising a hook on one element and an elongated bar on the next adjacent element having a hook end to coact with said hook, means on the element at the upper end of the assembly to ensaid post adjacent the top thereof to prevent disassociation of said assembly relative to said post, and means on the lowermost telescoping element to engage .said carriage for extending and collapsing said assembly as said carriage moves downwardly and upwardly respectively.

8. In a lift structure, a lift cariage, a post for vertically guiding said carriage, and a shield for said post comprising a plurality of assembled telescoping elements, means adjacent the top of one element and adjacent the bottom of the next elemen` for engaging each other to prevent clisassociation of said telescoping elements, and disengage-,able hooks on the upper and lower telescoping elements respectively for engaging the top of said post and said carriage respectively.

9. In a lift structure, an angle shaped post, a lifting screw between flanges thereof, a cartiage having element vertically guided and actuated by post and screw respectively, and a shield for said screw comprising a plurality of assembled telescoping elements enclosing the open side of said angle shaped post, hooks on said elements and elongated bars on each next adjacent element having hook ends to coact with said hooks for limiting the extension of said elements relat. to each other, means on the upper element for engaging said post and on the lower element for engaging said carriage to prevent deisassociation of the assembly relative to the post and telescopically actuating the assembly by movi-.nent of the carriage respectively.

l0. In a lift structure, an angle shaped post, a lifting screw between the flanges thereof, a carriage having an element vertically guided and actuated by said post and screw respectively, and a shield for said screw comprising a plurality of assembled telescoping elements enclosing the open side of said angle shaped post, means for limiting the extension oi said element relative to each other, means on the upper element for engaging said post and on the lower element for engaging said carriage to prevent disassociation of the assembly relative to the post and telcscopically actuating the asse-'ably by movement of the carriage respectively, said means for limiting the extension of said elements comprising a strap secured to one end of one clement and projecting longitudinally of said element toward the other ond thereof, hook on the free end of said strap, and a cooperating hook on the correspondingly opposite end of the next succeeding telescoping element.

ll. In a lift structure, a vehicle axle supporting rail, an axle block mounted thereon, said axle block com 4rising a block element resting on the rail, guide` means on the Block element engaging the sides of said rail to prevent lateral movement of the block element relative to the rail, and iianges at each side ol said block element engaging the under side of the rail to prevent disconnection of the block element relative to the rail, said flanges being diagonally arranged to permit disengagement thereof from the under side of said rail when the block element is twisted relative to the rail.

12. In a lift structure, a vehicle axle supporting rail, an axle block mounted thereon, said axle block comprising a block element resting on the rail, guide means on the block element engaging the sides of said rail to prevent lateral movement of the block element relative to the rail, and flanges at each side of said block element engaging the under side of the rail to prevent disconnection of the block element relativey to the rail, said flanges being diagonally arranged to permit disengagement thereof from the under side of said rail when the block element is twisted relative to the rail, said guide means normally preventing such twisting, said flanges being normally suciently spaced from said rail to permit said block element to be tipped to cause said guide means to clear said rails.

13. In a lift structure, a vehicle axle supporting rail, an axle block mounted thereon, said axle block comprising a block element resting on the rail, and iianges at each side thereof engaging under the rail, said flanges being diagonally oppositely arranged on the block element to permit disengagement thereof from the under side of the rail when the block element is twisted relative to the rail.

14. In a lift structure, a vehicle axle supporting rail, an axle block mounted thereon, said axle block comprising a block element resting on the rail, guide means on the block element engaging the sides of said rail to prevent lateral movement of the block element relative to the rail, and flanges at each side of said block element engaging the under side of the rail to prevent disconnection of the block element relative to the rail, said flanges being diagonally arranged to permit disengagement thereof from the under side of said rail when the block element is twisted relative to the rail, and means to normally prevent such twisting comprising a handle extending from said block element and having a hook for engaging said rail.

l5. In a lift structure, a vehicle axle supporting rail, an axle block mounted thereon, said axle block comprising a block element resting on the rail, guide means on the block element engaging the sides of said rail to prevent lateral movement of the block element relative to the rail, and iianges at each side of said block element engaging the under side of the rail to prevent disconnection of the block element relative to the rail, said flanges being diagonally arranged to permit disengagement thereof from the under side of said rail when the block element is twisted relative to the rail, and means to normally prevent such twisting comprising a handle extending from said block element and having a hook for engaging said rail, said handle when the hook thereof is so engaged being under tension.

16. In a lift structure, a vehicle axle supporting rail, an axle block mounted thereon, said axle block comprising a block element resting on the rail, guide means on the block element engaging the sides of said rail to prevent lateral movement of the block element relative to the rail, and flanges at each side of said block element engaging the under side of the rail to prevent disconnection of the block element relative to the rail, said flanges being diagonally opposite to permit disengagement thereof from the under side of said rail when the block element is twisted relative to the rail, said guide means normally preventing such twisting, said flanges being normally sufficiently spaced from said rail to permit said block element to be tipped to cause said guide means to clear said rails, said'handle when the hook thereof is so tension.

1'?. In a lift structure, vehicle axle supporting rails, an axle block mounted on each rail, said axle blocks comprising each a block element having anges at each side thereof diagonally oppositely arranged to permit disengagement thereof from the under side of said rails when said block elements are twisted relative to said rails, a bar connection between said block elements, and a handle projecting from said bar for sliding said block elements relative to said rail, and for twisting them for disengagement purposes.

18. In a lift structure, a pair of vehicle supporting rails, an axle block on each rail comprising a block element resting on the rail and having guide means engaging the sides of the rails, and flanges engaging under the rails, said flanges being diagonally oppositely arranged on said block element to permit disengagement thereof from under said rails when the block is twisted relative to said rails, and a bar connecting said block elements for simultaneously moving them relative to said rails and twisting them relative to said rails.

19. In a lift structure, a pair of vehicle supporting rails, an axle block on each rail comprising a block element resting on the rail and having guide means engaging the sides of the rails, and flanges engaging under the rails, said flanges being diagonally oppositely arranged on said block element to permit disengagement thereof from under said rails when the block is twisted relative to said rails, and a bar connecting said blockV elements for simultaneously moving them relative to said rails and twisting them relative to said rails, said block elements having sockets to receive said bar, the bottom of said socket being open and said bar resting on said rails, whereby the weight of the vehicle on the block is transmitted through the bar to the rails.

20. In a lift structure, a vehicle axle supporting rail, an axle block mounted thereon, said axle block comprising a block element resting on the rail and flanges at each side thereof engaging under the rail, said flanges being diagonally oppositely arranged on the block element to permit disengagement thereof from the under side of the rail when the block element is twisted relative to the rail and means to normally prevent such twisting comprising a handle extending from said block element and having a hook for engaging said rail.

21. In a lift structure, a vehicle axle supporting rail, an axle block mounted thereon, said axle block comprising a block element resting on the rail and flanges at each side thereof engaging under the rail, said fianges being diagonally oppositely arranged on the block element to permit disengagement thereof from the under side of the rail when the block element is twisted relative to the rail and means to normally prevent such twisting comprising a handle extending from said block element and having a hook for engaging said rail, said handle when the hook thereof is so engaged being under tension.

22. In a lift structure, a pair of vehicle supporting rails, an axle block on each rail comprising a block element resting onthe rail and engaged being under able vertically, said automatic control element being operatively connected with said carriage for movement thereby at opposite limits of its travel, said controller having a manually operable control element extending from said vertical rock shaft, said automatic control element, upon vertical movement, moving said manually operable control element horizontally to rock said rock shaft to non-operating position of the controller upon either of said opposite limits being l0 assumed oy said lift carriage.

DON D. MYERS.

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