US2266398A - Wheeled jack - Google Patents

Description

Dec. 16, 1941.

e. ou Yu-z WHEELED JACK 5 Shee'ts-Sheet 1 Filed 001:. 25; 1-938 INVENTOR ATTORNEY Dec. 16, 1941'. QUAYLE 2,266,398

. WHEELED JACK Filed Oct. 25, 1938 5 Sheets-Sheet 2 INVENTOR MBY WM ATIORNEY' De. 16,1941; 6. QLIJAYLEI 2,266,398

WHEELED JACK Filed Oct. 25, 1938 S Sheets-Sheet 5 WWW -" INVENTOR I BY 5 47 ATTORNEY -G. QUAYLE WHEELED JACK Dec. 16, 1941.

5 Sheets-Sheet 4 Filed 001:. 25, 1938 M v INVENTOR BY z 4 404% ATTORNEY Dec. 36, 1941. G. QUAYLE WHEELED JACK Filed Oct. 25, 1938 5 Sheets-Sheet 5 ATTO'RNEY Patented Dec. 16, 1941 George Quayle, Philadelphia, Pa., assignor Yale & Towne Manufacturing Company,

to The Stamford, Conn, a corporation of Connecticut Application October 25, 1938, Serial No. 236,866

24 Claims.

This invention relates to a type of lifting ap paratus known in the art as a wheeled jack or dolly. I shall herein call it a wheeled jack.

A wheeled jack is a two-wheeled lifting device especially adapted for lifting one end of a semilive skid platform, that is, a skid platform having two wheels at one end and two legs at its other end. By lifting that end of the skid platform which rests on legs, off said legs, and on to the wheels of the wheeled jack, the semi-live skid platform is converted into a full live skid platform, or the equivalent of a four wheel truck.

In my invention, I utilize a form of engaging means between the jack and the skid platform which is well known in the art, that is, a trunnion on the jack having a socket cooperable with a pin depending downwardly from the skid platform. My invention is equally useful should it be desired. to use a pin on the trunnion and a socket on the skid platform, as is disclosed in some prior art constructions.

While I have indicated that the general type of structure disclosed by me is old in the art, I should like to point out generally several-important advantages which are inherent in the structure which I have conceived and shall hereinafter disclose. Other advantages will appear as a study is made of the specification which follows. As a feature of my invention, I utilize a construction in which it is necessary that the operator assume the full weight of the load on the wheeled jack as by lifting it somewhat beyond its elevated position, before he can lower the skid platform on to its legs. Moreover, the release of the load is accomplished, preferably, solely through the operation of a lifting handle, rather than through additional means working in conjunction with the lifting handle. In this way, I prevent accidental release of the lifting mechanism and the free swinging of the handle through the application of the loadto the wheeled jack. Those familiar with this art will fully appreciate the value of this construction, eliminating as it does the flying handle hazard.

As a further feature of my invention, I utilize a lifting handle or lever which is spring balanced at all times so as to remain in a vertical position withoutv any effort on the part of the operator. This is an extremely desirable construction, and has long been sought for in the art. Moreover, the means whereby the balanced handle is obtained are simple, and the spring whichis required to be used is enclosed so as to present a very sightly appearance, and so as to be fully operation, all as will has a further function in that it holdsthe various I parts of my jack assembled and positioned for be described.

The most important feature of my invention is, however, the simplicity of the construction of my new wheeled jack, whereby I am able to obtaineasy lifting with complete safety, and whereby I am able to control the load and to lower the same without operating any system of complicated controls. p I 7 I consider my invention a distinct and valuable contribution to the priorart and do not wish to be limited in my patent monopoly to the specific structure I have shown, but rather wish to be protected in the enjoyment of my patent monopoly against the utilization of various other structures which may be devised by those skilled in the art embodying the principles of my invention.

For a description. of the'structure I have devised, I shall refer to the drawings wherein Fig. 1 is a view showing a skid platform elevated by my wheeled jack and ready for movement by the operator. Fig. 2 is a View of my wheeled jack separated from the skid platform and in normal resting position on the floor. Fig. 3 illustrates the wheeled jack of my invention in partial section about to be applied to the downwardly depending pin of the skid platform. Fig. 4 illustrates the parts of Fig. 3 in a slightly different position and with the weight of the skid platform about to be assumed by the wheeled jack. Fig. 5 is a view showing the parts of Fig. 4 after the front end of the skid platform has been lifted and after the handle has been elevated somewhat and into position to move the load. Fig. 6 illustrates the position of the parts When the liftin lever has been moved into a position to release the trunnion locking mechanism so as to allow the lowering of the skid platform. Fig. 7 is a view looking downwardly on my wheeled jack with the tubular lifting lever shown in section. Figs. 8, 9 and 10 are perspective views of the parts forming my invention.

Referring now more specifically to the drawings and especially to Figsvl, 2 and 3, it will be noted that my wheeled jack or dolly cooperates with a semilive skid platform l0 having rear wheels H and front supporting legs l2. In Fig. 1 the skid platform is shown supported at its forward end by the wheels of my wheeled jack, but in Fig. 3 the skid platform ID is shown supported by its legs l2. Depending downwardly from the forward end of the skid platform is a pin l3 which is adapted to enter the socket [4 of the trunnion protected from any damage. My balancing spring I5 of'my Wheeled jack. Through lifting of the trunnion I5, by means to be described below, the front end of the skid platform is elevated from the position of Fig. 3 to the position of Fig. 1.

The construction of my wheeled jack is best illustrated in Figs. 3, 8, 9 and 10. There it will be noted that the wheels I8 support an axle I! on which is mounted the main frame I8, through bearing hubs IS. The main frame of course occupies that portion of the axle which is between the two wheels I6.

Bearing hubs 28 on the main frame support trunnion shafts 2| extending at each side from the trunnion I5, as is best illustrated in Fig. 10. In this way, the trunnion I5 is allowed to hang vertically from frame I8 at all times when free. A pair of gravity dogs 22, identical in function, are also pivotally mounted on the trunnion shafts 2|, their surfaces 23 cooperating with surfaces 24 formed on gravity detent plates 25 which are also freely mounted on the trunnion shafts 2I.

The two detent plates 25 are joined by a cross bar 25 preferably welded to the two plates. An angle iron 2'! is welded to the side Plates of the main frame I8 and forms a leg on which the entire dolly may rest in a manner best illustrated in Fig. 2.

In Fig. 8, I show a handle frame 28 which through bearings 29 is mounted on that portion of the main shaft II lying between the two side plates of the main frame I8. The handle frame 28 has fixed thereto as by welding or in any other preferred way, a tubular lifting lever 30 which has secured to its upper end a cross bar 3| forming a handle. The lifting lever 33 acts to lift the trunnion I 5 and therefore the skid platform,

when swung downwardly, as will be described presently.

Mounted on shaft I'I between the side plates comprising the handle carrying frame 28, is a locking lever 32 having a locking hook portion 33 and horizontally extending frame contacting surfaces 34. The end of the locking lever 32 opposite the hook portion 33 is designated by reference numeral 35, and is connected through a pin 35 with a vertical strut member 31 terminating at 38 in a piston-like portion having a lug 39. The piston-like portion 33 slides in the tubular lifting lever 38 asis illustrated. Between thelug 39 on piston 38 and an abutment 48 fixed nearthe upper end of lifting lever 38, there is mounted a spring 4!. It is obvious that this spring tends to separate portion 35 of the locking lever 32 from the handle 33. As a matter of fact, the operation of the spring 4'I will best be appreciated if it be considered that its action is the same as though a spring were inserted in the space 42 in Fig. 3 between the tubular lever 38 and handle carrying frame 28 on the one side, and the main frame It and arm 35 of locking lever. 32 on the other side.

The surfaces '34 extending horizontally from the locking lever 32, best illustrated in Fig. 8, are forced by the spring 4| against the lower angular surfaces of the side plates of main frame I8, as is best illustrated in Fig. 3, and tend to rotate frame I8 in a counter clockwise direction about the shaft I1. At the same time, of course, the lifting lever 30' and handle carrying frame 28 are being rotated by the spring 4| in a clockwise or upward direction. It is the function of the dogs 22 previously described, to prevent the collapse of the entire apparatus and to maintain the apparatus properly assembled and positioned. For this purpose, the dogs 22 are equipped with notches 43 which in the normal position of the parts, coact with lugs 44 of the handle carrying frame 28 to maintain the frame and handle in the position of Fig. 3, and with the space 42 between the handle carrying frame 28 and the main frame I8.

The lower end of trunnion I5 is formed with a locking nose 45 which is adapted to engage with the hook portion 33 of the locking lever 32 under conditions to be described presently. It will also be well to indicate that the gravity detent plates 25 are formed with surfaces 45 which cooperate with detent surfaces 41 of the locking lever 32, best shown in Fig. 8, all for a purpose to be described presently.

I shall now refer to the series of Figs. 2, 3, 4, 5 and 6 to describe one complete lifting and lowering operation of my wheeled jack. Referring now to Fig. 2, it will be noted that the wheeled jack is supported through its wheels I6 and leg 2'! on the floor. The dogs 22 cooperate with lugs 44 on the handle carrying frame 28 to maintain the handle carrying frame and the main frame in the position of Fig. 2 and against collapse through the action of the handle balancing spring 4!. The trunnion I5 hangs in a substantially vertical position, and of course the locking lever 32 is positioned with its surfaces 34 against the lower edges of the side plates of the main frame I8 by the pressure of the handle balancing spring 4|.

By swinging the tubular lifting lever 38 from its position of Fig. 2 to its position of Fig. 3, the trunnion I5 may be positioned with its socket I4 directly under the pin I3 of the skid platform, as in Fig. 3. The parts of the wheeled jack remain, however, in the same relation as in Fig. 2, all through the action of the dogs 22 which maintain the handle carrying frame 28 in somewhat spaced relation to the main frame I8, the space being shown and designated by reference numeral 42 in Fig. 3.

Downward swinging of the lifting lever 38 to its position of Fig. 4 moves the trunnion I5 against the surface 43 from which depends the pin I3 of the skid platform. Once this has been done, it will readily be appreciated that the trunnion I5 will accept the load on the skid platform, and that it will thereafter be possible to rotate the handle carrying frame 28 through downward pressure on the lifting lever 33 in opposition to the pressure of the handle balancing spring 4|. This brings the parts into the position of Fig. 4 and releases the handle carrying frame 28 from dogs 22 which dogs then drop by gravity until their surfaces 23 contact the surfaces 24 of the gravity detent plates 25. This is actually the position of the parts in Fig. 4. No lifting has taken place. All that has happened is the compression of handle balancing spring 4|, and the releasing of the lifting lever from dogs 22.

The actual lifting of the skid platform by further downward swinging movement of the lifting lever 38 is best illustrated in Fig. 5. There it will be noted that the main frame I8 has been rotated to bring the trunnion shafts H and the trunnion I5 into a position corresponding to an elevation of the front end of the skid platform I 0. The cam surface 45a to the rear of the locking nose 45 of the trunnion I5, has, during this movement of the main frame I8, first contacted the cam surface 49 of the locking lever 32 so as to cam the locking lever downwardly against the force of the balancing spring 4i. As the hook portion 33 of the locking lever 32 then moved into a position opposite the locking nose 45 of the trunnion l5, the locking-lever 32 moved under the influence of the spring 4i whereby to effect the engagement of the locking nose 45 with hook 33, as is illustrated in Fig. 5.

With the parts in this position, it is obvious that the trunnion I5 is locked by the locking lever 32 relatively to the main frame l8 and the axle i1, so that the main frame can no longer rotate relatively to the trunnion l5. Since the trunnion of course cannot rotate due to the action of pin 13, the skid platform I will be maintained in its elevated position supported by the wheels it of my wh'eeled jack. The lifting lever 30 and its carrying frame 28 may now be moved as to their position of Fig. to transport the skid platform to any desired location, without any interference from dogs 22.

Should it now be desired to lower the load, it is of course necessary to first release the trunnion l5 from the locking lever 32 by the movement of the hook 33 of the locking lever 32 away from the nose 45 of the trunnion. This is accomplished by the operator of the wheeled jack assuming the load by proper manipulation of the lifting lever. The release of the trunnion I5 is best illustrated in Fig. 6, wherein it will be noted that the lifting lever 30 has moved the main frame l8 about the axis of the axle I! to a position somewhat beyond the normal elevated position of Fig. 5.

Since during this movement of main frame IS the trunnion I5 is held by the skid platform pin 13 against any rotary movement whatsoever, the following action takes place: The cam surface 50 of the locking lever 32 moves against the surface 45a of the trunnion as the locking lever 32 moves with the main frame l8 to the position of Fig. 6, and the fixed trunnion surface 45a forces the locking lever 32 out of locking relation to the trunnion and into a position wherein detent surfaces 41 of lever 32 interlock with the surfaces 46 of the gravity detent plates 25. This movement of lever 32, of course, releases main frame l8 for movement relatively to the trunnion l5. It should be noted also that the movement of the gravity plates 25 into the position of Fig. 6, that is, into cooperation with the detent surfaces 41 of lever 32, moves the dogs 22 into position for cooperation with the lugs 44 of the handle carrying frame 28, all as is quite apparent.

If now the operator allows the lifting lever 30 to move upwardly, the detent plates 25 will continue holding the locking lever 32 so that its looking hook portion 33 will move past the locking nose 45 of the trunnion without engaging it. This will allow a rotation of the main frame l8 about the axle l1 and relatively to the trunnion l5 so as to lower the trunnion and place the load of the skid platform on its legs l2. At the same time, the dogs 22 will have dropped by gravity with their surfaces 23 against surfaces 24 of the detent plates 25. This moves the notches 43 of dogs 22 into cooperation with the lugs 44 ofthe handle carrying frame 28, as is seen in Fig. 6, so as to control that frame.

When the skid platform has been positioned so as to be supported by its legs I2, a further rotation of the handle carrying frame 28 and the lever 30 will bring the bar 26 connecting detent plates 25 against the flat surface 26a of the trunnion [5 so that the plates 25 are incapable of further rotation with the locking lever 32. A slight further movement of the locking lever 32 with the lifting lever 30 and frame l8, releases the locking lever from the detent plates 25, restoring the locking lever 32 to its normal functioning position ofFigs. 2 and 3. 1

I believe that the simplicity of operation ofmy invention will now be apparent. It will also be apparent that many changes in actual structure may be made without departing from the basic principles of my contribution to the art.

I now claim: 7

1. In a combination of the class described, a frame mounted on a-wheel supported shaft for rotation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted and to be maintained by said means thereafter in a predetermined position, a locking lever pivoted relatively to said frame and adapted to lock said frame relatively to said trunnion when said trunnion is in an elevated position whereby to lock said frame against reverse pivotal movement to lower said trunnion, a lifting lever for rotating said frame about said axis whereby to lift'said trunnion, and means actuated by rotation of said frame somewhat beyond a position corresponding to full lifting of said trunnion, for releasing said trunnion from said locking lever.

2. In a combination of the class described, a frame mounted on a wheel supported shaft for rotation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted and. to be maintained by said means thereafter in a predetermined position, a locking lever pivoted relatively to said frame and adapted to lock said frame relatively to said trunnion when said trunnion is in an elevated position whereby to lock said frame against reverse pivotal movement to lower said trunnion, a lifting lever for rotating said frame about and means.

whereby application of lifting pressure by said lifting lever to move said frame and trunnion beyond the elevated position of said trunnion releases said trunnion from said locking lever.

3. Ina combination of the class described, a frame mounted on a wheel supported shaft for rotation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted and to be maintained by said means thereafter in a predetermined position, a locking lever movable to lock said frame relatively to said trunnion when said trunnion is in an elevated position whereby to lock said frame against reverse pivotal movement to lower said trunnion, a lifting lever pivoted relatively to said frame and adapted to rotate said frame about said axis whereby to lift said trunnion, and a spring between said lifting lever and said locking'lever tending to rotate said levers in opposite directions.

4. In a combination of the class described, a frame mounted on a wheel's'upported shaft for rotation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted and to be maintained by said means thereafter in 'a'predetermined position, a locking lever movable to lock said frame relatively to said trunnion when said trunnion is in an elevated position whereby to lock said frame against reverse pivotal movement to lower said trunnion, a lifting lever for rotating said frame about said axis whereby to lift said trunnion, a

spring between said liftin'g'lever; and said locking lever tending to rotate said levers in opposite directionsand a dog pivoted on said frame and @Q l il l l morall ii? 34 ift n l t l? 9 maintain said lifting lever against said rotation.

a I a eemb ne i a f e las descr be a fram mou te a whe l temm a t for reiatien n. the rt f s id haft. a l f ing r nn on r e ed on aid trams seie meni e being adapted fo ee ae eieei w th mea s 01- k platform to be lifted and to be maintained by s id mean h r after in a predetermined posiion; i 1991i er, m v 2 9? said ra relati el t aid tr nn n en s trunnion n an le at pos t on h 110 k sa frame. a a ns e erse q a m em n o lower sai runn n a l f in eve f a n Said rame abou aid x s wh eby to t e i trunni n a spr n betwee s d ng lev a Said locking lever tending to rotate said levers in opp s ts d re ives m an ai o ki level pressing on said frame and thereby tending to impart rotation to said frame, and means between said lifting lever and said frame for limiting the relative movement between said lifting lever and said frame, whereby said spring holdssaid frame, locking lever and lifting lever in pred te -mined r la d etition Q. In a combination of the class described, a frame mounted on a Wheel supported shaft for otat qn t e axis of a a t f ng t nion pivoted o said frame, said trunnion being adapted for enga ement with means on a skid platfOl'm to be lifted and to be maintained by said means thereafter in a predetermined posi tion, a locking lever movable to lock said frame relatively to said trunnion when said trunnion is in an elevated position whereby to lock said frame against reverse pivotal movement to lower said trunnion, a lifting lever for rotating said frame about, said axis whereby to lift said trunnion, means for releasing said locking lever from said trunnion when said trunnion and frame are moved to a position slightly beyond the normal lifted position of said trunnion, and means for thereafter maintaining said locking lever in releasing position until said trunnion and frame move to a lowered position.

'7. In a combination of the class described, a frame mounted on a wheel supported shaft for rotation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted and to be maintained by said means thereafter in a predetermined position, a locking lever movable relatively to said frame and adapted to lock said frame relatively to said trunnion when said trunnion is in an elevated position whereby to lock said frame against pivotal movement to lower said trunnion, a lifting lever for rotating said frame about said axis whereby to lift said trunnion, and means for releasing said locking lever from said trunnion when said trunnion and frame are moved by said lifting lever to a position slightly beyond the normal lifted position of said trunnion and for thereafter maintaining said locking lever in releasing position until said trunnion and frame move to a lowered position.

8. In a combination of the class described, a frame mounted on a wheel supported shaft for rotation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted and to be maintained by said means thereafter in a predetermined position, a locking lever pivoted relatively to said frame and adapted to lock said frame relatively to said trunnion when said trunnion in an elevated position whereby to lock said frame against pivotal movement to lower said trunnion, a lifting lever for rotating said frame about said axis whereby to lift said trunnion, means for releasing said locking lever from said trunnion when said trunnion and frame are moved to a position slightly beyond the normal lifted position of said trunnion, a detent adapted to hold said locking lever in releasing position thereafter to allow lowering movement of said frame and trunnion, and means for moving said detent out of holding position as said trunnion is lowered whereby to restore said locking lever to its normal functioning position.

QQIn a combination of the class described, a frame mounted on a wheel supported shaft for rotation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted and to be maintained by said means thereafter in a predetermined posi: tion, a locking lever movable to lock said frame relatively to said trunnion when said frame ele-, vates ai r ni n t ro gh o at on on s ax a lifting lever for rotating said frame to lift said trunnion, and a surface of said trunnion cooperable. with said looking lever to earn said leverout of looking position when said frame and locking lever are rotated to a position beyond the DQ tion corresponding to a normal elevation of said trunnion. v

10. In a combination of the glass described, a frame mounted on a wheel supported shaft for rotation n h a is 'e said haft i in tru nion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted whereby to be maintained by said means thereafter in a' predetermined position, a locking lever movable to lock; said frame relatively to said trunnion as said frame elevates said vertically maintained trunnion through rotation on its axis, the said rotation of said fr m mo n a d o leve nt e k n r lation to said trunnion, a lifting lever for r0: tating said frame to lift said trunnion, a surv face of said trunnion cooperable with said look: ing lever to cam said lever out of locking position when said frame and said locking lever are rotated to a position beyond the position corremndi e a n rma l a n f e runnion n a d nt wan ed a hol sa d 99. 9% lev r in fireme r ea i res gr hereafte h eb to allow reverse rotation of said frame to lower said trunnion. I

11, In a combination of the class described, a frame mounted on a wheel supported shaft for rotation in the axis of saidshaft, a lifting'trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted and to be maintained by said means thereafter in a predetermined position, a locking lever movable to lock said frame relatively to said trunnion as said frame elevates said vertically maintained trunnion through rotation on its axis, the said rotation moving said locking lever into looking relation to said trunnion, lifting lever for rotating said frame to lift said trunnion, a surface of said trunnion coopernble with said locking lever to cam said lever out of locking position when said frame is rotated to a position beyond the position corre sponding to a normal elevation of said trunnion, a det t da d to o d aid lock n lever n tru eie e e sin posi on the eaf r o. a l w reverse rotation of said fram to lower said trunnion, and means for cainin'ing said detent outer holding relation to saidlockingTlever'as. said trunnion is lowered whereby'to restore said'looking lever to its normal'functioning position.

12. In a combination ofthe class described, a frame mounted on a wheel supported shaft for rotation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a' skid platform to be lifted and to be maintained by said means in a predetermined position, a locking lever pivoted relatively toi said frame, a lifting lever for rotating said frame about its axis whereby to lift said trunnion, spring means pressing said lifting and locking levers in opposite directions, said locking lever being adapted to lock said frame to said trunnion when said frame elevates said'vertically maintained trunnion through rotation on its axis, a dog pivoted on said frame and adapted to lock said lifting lever against said spring pressed movement beyond a predetermined position allowing said lifting lever a slight amount of free rotation against said spring pressure prior to actuating said frame,

the rotation of said lifting lever through said u distance against said spring pressure and while said trunnion and frame are held by contact with the means on the skid platform being sufficient to release the lever from said dog.

13. Ina combination-of the class described, a 1 i frame mounted on a wheel supported shaft for rotation in the axis 'of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be liftedwhereby to be maintained i by said means in a vertical position, a locking lever pivoted relatively to said frame, a lifting lever for rotating said frame about its axis whereby to lift said trunnion,spring means pressing said lifting and locking levers in opposite directions, said locking lever being adapted to lock said frame to said trunnion when said frame elevates said vertically maintained trunnion through rotation on its axis, a dog pivoted on said frame and adapted to look said lifting lever against said spring pressed movement beyond a predetermined position 1 allowing said lifting lever a slight amount of free rotation against said spring pressure prior to actuating said frame, the rotation of said lifting lever through said distance against said spring pressure and while said trunnion and frame are held by contact with the means on the skid platform being suflicient to release the lever from said dog, a surface of said trunnion cooperable with said locking lever to cam said lever out of locking position when said frame and said locking lever are rotated to a position beyond the position corresponding to a normal elevation of said trunnion, a detent adapted to hold said locking lever in trunnion releasing position whereby to allow reverse rotation of said frame to lower said trunnion while also moving said dog into position for locking said lifting lever once again against spring pressed movement beyond said predetermined position, and means for moving said detent out of holding relation to said locking lever as said trunnion is lowered.

14. In a device of the class described, a pair of wheels and a shaft supported thereby, a main frame rotatable about the axis of said shaft, a lifting trunnion pivoted on said frame and adapted to be lifted and lowered as said frame rotates on said axis, a lifting lever for rotating said frame, a spring pressing said lifting lever upwardly and in a non-lifting direction relatively to said frame,"and means between said frame and lifting lever for locking said lifting lever against said movement by said spring in a non-lifting direction while allowing rotation of said lifting lever in a downwardly or lifting direction relativelyfto said frame. l v

15. In a device of the class described, a pair of wheels and a" shaft supported thereby, a frame rotatable about the axis of said shaft, a lifting trunnion pivoted on said frame and adapted to be lifted and lowered as said frame rotates on said axis, a lifting lever for rotating said frame, a spring pressing said lifting lever upwardly and in a non-lifting direction relatively to said frame,

a dog carried by said main frame for locking said lifting lever against said spring pressed movement while allowing free rotation of said lifting lever in a-downwardly or lifting direction relatively to said frame, and a foot on-said frame for supporting it and its trunnion and said lifting lever in a resting-position. v I

16. In a device of the class-described, a pair of wheels and a shaft supported thereby, a frame rotatable about the axis of said shaft, a lifting trunnion pivoted on said frame and adapted to be lifted and lowered as said frame rotates on said axis, aliftinglever adapted to rotate said frame about said axis whereby to lift said'trunnion, a balancing spring pressing said lifting lever upwardly and in a non-lifting direction relatively tosaidframe, anda gravity dog carried by said frame for locking said lifting lever against said spring pressed movement beyond a predetermined position relatively to said frame, while allowing free rotation of said lifting lever in a'downwardly or lifting direction relatively to said frame. l 7

17. In a combination of the class described, a frame mounted on a wheel supported shaft for r0- tation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on askid platform to be lifted and to be maintained. by said means thereafter in a predetermined position, a locking lever pivoted relatively to said frame and adapted to lock said frame relatively to said trunnion when said trunnion is in-an elevated position whereby to lock said frame against reverse pivotal movement to lower said trunnion, a lifting lever of tubular form for rotatg said frame about said axis whereby. to lift said trunnion, a spring in said tubularlifting lever, and means for securing said spring relatively'to said frame for pressing said tubular handle and said frame in. opposite directions.

18. In a combination of the class described, a frame mounted on a wheelsupported shaft for rotation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted and to be maintained by said means thereafter in a predetermined position, a locking lever pivoted relatively to said frame and adapted to lock said frame relatively to said trunnion when said trunnion is in an elevated position whereby to lock said frame against reverse pivotal movement to lower said trunnion, a lifting lever of tubular form for rotating said frame about said axis whereby to lift said trunnion, a spring in said tubular lifting lever, means whereby said spring is secured at its lower end to said locking lever, whereby said spring tends to swing said tubular handle upwardly relatively to said frame while simultaneoiis'ly pressing said locking lever in a locking dir'eetioh. V i

i 19. In a 'coinbin'ationof the class de's'cribeda frame inbi'inted on a wheel supported shaft for rotation the axis of "said shaft, a lifting trun' man pivoted on said frame, said trunnion being adapted for engagement with means on a skid platferrn to b'e lifted and to be maintained by said means thereafter in a predetermined position, a locking means for locking said frame relativelyto said trunnion when said trunnion is in an elevated pp saian whereby to l oek said frame against revi se pivotal movement to lower 's'aid PI 'llIQfliQIi, a V lifting lever jfor rotating said frame about said axis wherebyto lift said trunnion, and means actuated by rotation of said frame seine- Wh fi ybnd @P dti flQ I Pd Qfi 56 l l ing of said trunnion for releasing said trunnion om sa oc n me p, 20; In a combination of theclass described, a frame mounted on a wheel supportedshaft for rotation in the axis of said shafta lifting trunnion piyoted on said frame, said trunnion being adapted for engagement with means ona siiid 'platforrnto belifted and to be maintained bysaid means thereaftenin a predetermined position, locking means for locking said frame relatively to said trunnion when said trunnion is in an ele: vated position, whereby to lock said frame against reverse pivotalmovement to lower said trunnion, a lifting leverfor rotating said frame about said axis whereby to lift said trunnion, means actuated by rotation of said frame somewhat beyond a position correspondingto full lifting of said trunnion for releasing said trunnion from said locking means, and means for holding said looking means out of locking position until said trunnion is lowered.

21'. In a combination of the class described, a frame mounted on a wheel supported shaft for rotation in the axis of said shaft, a lifting trunnion pivoted on said frame, said trunnion being adapted for engagement with means on a skid platform to be lifted and to be maintained by said means thereafter in a predetermined position, a locking lever pivoted relatively to said frame and adapted to lock said frame relatively to said trunnion when said trunnion is in an elevated position whereby to lock said frame against pivotal movement to lower said trunnion; a lifting lever for rotating said frame aboutsaid axis whereby to lift said trunnion, means for releasing said locking lever from said trunnion when said trunnion and frame are moved by said lifting lever to a position slightly beyond the normal lifted position of said trunnion, means for thereafter maintaining said locking lever in releasing position until said trunnion and frame move to "a lowered position, and means for mov'- ing' saidlast means out of maintaining position when said trunnion is lowered.

22., In a device of the class described, a pair of wheels and a shaft supported thereby, a main frame 'rgitatable about the axis of said shaft, a lifting" t unnion pivoted on said frame and adapted to be lifted and lowered as said frame rotates 'on said axis, a lifting lever for rotating said frame, a spring pressing said lifting lever upwardly and in a scanning direction relatively to said frame, a do'g for locking said lifting lever against rotation bysaid spring relatively to saidfr'ame beyond a predetermined position, said lifting lever moving against said spring pressure relatively to said frame when said frame is held against movement with said lever as when said trunnion is n engagement with a load to be lifted, said relati" movement between the lifting lever the frame releasing the lifting lever from said dog. a

23. In a device of the lass described, a pair of wheels and shaft siipportd thereby, a main framerotatable about the axis of said shaft, a lifting trunnion pivoted on said frame and adapted to be lifted and lowered as said frame rotates on said axis, a lifting iey -ior rotating said frame, a spring pressing said liftinglever upwardly and in a non-lifting direction relatively to said frame, and means between said frame and lifting lever for locking said lifting lever against said movement by said spring in a non-lifting direction while allowing rotation of said lifting lever in a downwardly or lifting direction relatively to said frame when said frame is held against movement with said lever as when said trunnion is in engagement with a load to be lifted.

24. In a device of the class described, a pair of wheels and a shaft supported thereby, a main frame rotatable about the axis of said shaft, a lifting trunnion pivoted on said frame and adapted to be lifted and lowered as said frame rotates on said axis, a lifting lever for rotating said frame, a spring pressing said lifting lever upwardly and in a non-lifting direction relatively to said frame, means between said frame and lifting lever for locking said lifting lever against 'said movement by said spring in a non-lifting direction while allowing rotation of said lifting lever in a downwardly o'r lifting direction relatimely to said frame when said frame is held against movement with said lever as when said trunnion is in engagement with a load to be lifted, said relative movement between the liftiiig lever and said frame releasing said lifting lever from said means.

GEORGE QUAYLE.

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