US2110424A

US2110424A - Hand lift truck

Info

Publication number: US2110424A
Application number: US69478A
Authority: US
Inventors: Quayle George
Original assignee: Yale and Towne Manufacturing Co
Current assignee: Yale and Towne Manufacturing Co
Priority date: 1936-03-18
Filing date: 1936-03-18
Publication date: 1938-03-08
Anticipated expiration: 1955-03-08

Description

G. QUAYLE HAND LIFT TRUCK March 8, 1938.

Fiied March 18, 195e 3 Sheets-Sheet 1 ATTORNEY March 8, 1938. G, QUAYLE 2,110,424

' HAND LIFT TRUCK Filed March 18, 1956 5 Sheets-Sheet 2 JVENTCR CV 60% ATTORNEY March s, 193s. G. QUAYLE 2,110,424

HAND LIFT TRUCK Filed March 18, 1936 3 Sheets-Sheet 5 INVENTOR ATTORNEY Patented Mar. 8, 1938 HAND TRUCK George Quayle, Philadelphia, Pa., assigner to The Yale & Towne Manufacturing Company. Stam. ford, Conn., a corporation of Connecticut Application March is, 193s, serial No. 69,478

26 Claims.

by the truck, the load being mounted on pallets' and therefore requiring a low extending type of overhanging fork load frame for its handling. My truck is especially adapted for handling rela-7 tively heavy sheets of tin plate stored on pallets, and forthis purpose I use forks movable into a very low position and adapted to be elevated to a position wherein the load may be transported'.

It will be readily appreciated that the placing of a relatively heavy compact loaden overhanging forks upsets the normal balance of a truck of the class described, so that it will tip readily when accepting the load and will be incapable of transporting the load, even should it be possible to actuallylift the load. My invention relates especially to means for facilitating the lifting of mounted on a relatively light hand lift truck, and to means for thereafter facilitating the moving of the load on the truck.

, Before describing in detail my truck, it may be well to indicate generally the basic operating principles thereof, and to indicate'generally the Y characteristics of the features whereby it is made to operate efficiently.

` Preferably, my truck comprises a main frame having at its front end a lifting mechanism which may be of any type well known in the art, but which I prefer to be of the type shown in the Stuebing patent, No. 1,785,368. This lifting mechanism is connected to a lifting frame, which in this case, is 'preferably a pair of forks which, are to be lifted relatively to the main frame, but which need not actually be even connected to the main frame. A presser foot is adaptedvfor co` operation with the lifting frame, or the forks, as

a relatively heavy load on overhanging forks" 'of the truck. Thelifting forks are preferably.

' supported relatively to the main frame by the presser foot, so that any load imposed on the forks will immediately move the presser foot into a downward position against the ground. The lifting mechanism at the front end of the truck is interconnected to the presser foot and lifting forks so that it tends to separate the two on operation of the lifting mechanism. This, of course, acts to elevate the forks and the load."

As a further feature of my invention, the forward load supporting wheels of the truck are mounted for lateral movement relatively to the truck once the lifting forks have been elevated and the load assumed by the presser foot. As a further feature, the main frame itself is actually elevated relatively to the presser foot so as to relieve the forward wheels of the load. Then, the operator need only move the wheels laterally into a. position directly under the elevating forks, which will of course still be supported by the presser foot. If now the lifting mechanism be released as described in the Stuebing patent, the lifting forks will come down into a lower position against supporting means associated with the load wheels, thus relieving the presser foot of the load. Thereafter, the springs which maintain the presser foot in an upper -position will be free tomove the presser foot into the Asaid upper. position, land the truck may then be moved freely.

There are, of course, further features of the invention which I shall describe in more detail hereinafter.' I believe my invention to be of a very basic nature, and I do not wish to be limited to any particular modification, but rather believe myself entitled to broad claims and a broad interpretationv of those claims.

Fora detailed description of my invention, I shall now refer to the drawings wherein Fig. 1 is a partial section along lines I-I of Fig. 4. Fig. 2 isa view of the forward portion of the truck shown in Fig. l, with the lifting forks in an elevated position and with the load being supported byl the presser foot. Fig. 3 is a vlew of that portion of the truck shown in Fig. 2 with the load wheels moved to a position under the lifting forks, and 'with the lifting forks supported thereby for movement.V Fig. 4 is -a top view of the parts of Fig.- 1 with the check eliminated for purposes of v clarity. Fig. 5v is va view taken along lines 'S4- 5 of Fig. l. Figs. 6, 7 and 8 are perspective views of the .presser foot, thelifting forks and the mov-fv ing handle` I2 and steering wheels Il. all of which operate as described in the Steubing patent supra. In Fig. 5, I show some of the mechanism of the steering head II, the main portion of this `mechanism being the lifting ratchet wheel I4,

which is operated by pumping movement of the handle I2 and actuates the lifting mechanism through a pair of crank arms I5. Since this mechanism is old in the art and does not form a part of my invention, I shall naturally not go into further detail in describing it. Suflice it to say that this type of lifting mechanism, or any type well known in the art, may quite well cooperate with the features of my inventi'onpin a 2|. Earsj22 are similarly formed'at the lowerl portion of the member I8 of the presser foot, and links 23 pivotedto the main frame at 24 connect the ears 22 to the main frame. The presser foot has a further pairofears 25 ca rrying a horizontal member 26, drilled atv 21 for cooperation with springs 28. These springs are suspended from an 'L-shaped member 28 on the main frame, and thus resiliently support the presser foot relatively to the' main frame in its pomtion illustrated in Fig. 1.

The lifting frameispreferably in the form of forks 30, having vertical portions Il connected by a horizontal bracing member 32, and a further bracing member 3l.` Lower ears 34 are secured t to thevvertical portions II and these ears are' connected to the main frame` I Il through means of links 35,*which links are pivoted to the main` frame `on the axis 24, or the same axis on which the links 23 -'o f the presser foot are pivoted. Similarly, the vertical portions 8l have upper ears 36 carrying'links I1 pivoted to the main frame through shaft 2I,'which is the same shaft that supportsv the link 20 of the presser foot.

While,- of course, I have shown the lifting forks pivoted to the main frame on the same axis as the presser foot, it should be understood that it maybe'pivoted on vother axes or otherwise' supported relatively to the presser foot itself. While the basic relationship of the presser foot and forks should preferably be that herein described, this basic relationship may take any number of ydlil'erent forms.

A check member Il of the ,fluid type well known in this art is connected to the upper horizontal bracing member 3l of the forks at 33a, and at its lower end to the bracket 88 fixed on the'mem- Yber I8 of the presser foot, as is shown in Fig. 5.

This check acts to slow down the movement between the lifting forksl and the presser foot, as will be readily understood by those skilled in the art. n

Each of the ears 25 of the presser foot is drilled 4out as at 4l for the support of the shaft 4I, at

each end of which is mounted an arm 42 connected by pivot 48 with a pair of link members 44. best illustrated in Fis. 5. Each pair of link members 44 is in turn pivoted at 45 toeach of the .l bell crank arms I5 of the lifting mechanism. in-A cluding the ratchet I4 maintained in lifting head II Each of thebellcrank levers 42 is connected, through a pivot 48, with a link 41 pivoted at 44 to one of the lower ears 84 of the lifting forks 8l.

It will readily be appreciated by viewing F188. 1 and 2 that when the bell crank arms Il are rotated clockwise by operation of the lifting handie I2,'the bell crank 42 will be rotated clockwise through its connection with the links 44, thus lifting the forks III relatively to the presser foot I5 by, in effect, separating the presser foot and the lifting forks in a manner well shown in Fig. 2. In effect, the toggle including pivot 40 on the presser foot and pivot 48 of the lifting forks, and

members

42 and 21, is straightened for obtaining the movement just described. Should there be no loadon the lifting forks 30, this movement of the lifting forks relatively to the presser foot may be mere relative movement without the presser foot actually coming in contact with the ground. However, if there is a load, such as "A" of Fig.V 2, on the lifting forks 30, then that load will'be accepted by the .presser foot I8 which will move with its presser feet I1 into a position against the ground and against the resilient force of springs 28. This movement will occur immediately upon the application of 'load A" to the forks 30. Thereafter, operation of the lifting" mechanism will tend to separate the lifting forks vfrom the presser foot more and more until the load is fully elevated, as shown in Fig. 2.

The main frame I Il of the truck is equipped with lugs 49 cooperable with lugs 50 on the lifting forks so that when the lifting forks reach the position of Fig. 2, the main frame III is elevated by the forks relatively to the presser feet I1.

.'I'his moves the frame from a position wherein it rests on supporting portions 50 carried by frame members 5I, which in turn carry the load wheels 52, through means of the axle 5l. 'Ihe frame members 5I of the load wheels 52 are-movable' laterally-from the position illustrated in Hg. 1 to the position illustrated in Fig. 3, through means of a lever 54 pivoted to the frame members 5I at 55, andpivoted at 58 to the main frame I0, and having a relatively long extending portion 51 whereby the moving leverage may be obtained.

With the load elevated as in Fig. 2, and with the main frame no longer resting on the upper surfaces of the members 50, the frame members 5I may be moved from.the position of Fig. 2 to the position of Fig. 3v with very.little eifort on the Ipart of theoperator, by merely rotating the lever manner well known in the art, and best described4 in the Stuebing patent previously referred to,

the forks 30 will tend to descend, checked of.

course by the member 38 until they rest on the `member 50 supported by the frame 5I and'load `wheels 52, as is well-illustrated in Fig. 3. As

soon as the members 50 accept the load of the forks 30, the springs 28' will no longer be stressed by the load and they willact to pull the presser foot I6 upwardly so as to remove the presser feet -I1 from the ground.

' The presser feet I1 have lug portions Il and Il. The lugs 58 cooperate with the axle 58 in the potain it relatively rigid. Similarly. in Fig. 3 the lugs 59 cooperate with the axle for maintaining it relatively rigid.

I believe that thev operation of my n simon or the parts iuustrated ni Fig. rana mlns" now be relatively clear to those skilled in the art, but it may be well to go through one complete operation in order to even better clari its action.

In the initial position of the truck, the forks 30 constituting thelifting platform are in the position of Fig. 1, and the main frame is supported on members 50, while the axle 53 is held in position by cooperationv with the lugs 58 on the presser feet I1, the presser foot being maintained in an upper position with the feet off the ground through means of springs 28. Operation of the lifting handle I2 serves to rotate the crank arms I5 which in turn pull on the'links 44 and rotate thebell cranks 42 for moving the lifting forks relatively to the presser foot. If there is a load on the forks sufficient to overcome the springs 28, that load will naturally be transferred` to the presser foot, which will move through its

links

20 and 23 relatively to the main frame into the position of Fig. 2 with the feet II against the ground.' Thereafter, further operation of the lifting handle I2 will elevate the forks to the position of Fig. 2 and will at the same time, through the coaction of

lugs

49 and 50, move the main frame I 0 off* its support on the members 50. At this point, the portions of check 38 Will reach a fully outstretched position' ready to absorb the movement of the load downwardly with the lifting forks when the elevating mechanism in the head II is released.

If it is desired to move the load A of Fig. 2, it is merely necessary to apply effort to the extension 51 of the member 54 and rotate that member against the force of spring 54a from the position of Fig. 1 to the position of Fig. 2, wherein the wheels 52 wi" be positioned under the load forks 30. If the lifting mechanism in the head II is then released, the forks will descend slowly under the control of the check 38 until they rest on the members 50. Thereafter, the load being taken off the presser foot I6, the presser foot will rise under the inuence of springs 28 until its lugs 59 abut the axle 53 for holding the axle in position.' Incidentally. in this position of the parts, the'spring 54a. will act also to hold the lever 51 and therefore the wheel assembly in its I proper operating position.

I now claim: 1. In a lift truck of the class described, a main frame, a load liftingframe, elevating means on said main frame, toggle means, in effect, operated by said elevating means for elevating said load lifting frame relatively to said main frame, and means movable against the ground and into truck'stabilizing position actuable incidental to the elevating of said load lifting frame.

2. In a lift truck of the class described, a main frame', a forwardly extending load lifting frame supported by said main frame, means for elevating said load lifting frame relatively to said main frame, presser means movable against the ground incidental to the elevating `of a load and said load lifting frame by said elevating means whereby to prevent tipping of said truck, a longitudinally movable wheeled frame normally under said main frame, means whereby said wheeled frame is moved to a position under said lifting frame when said frame is elevated, whereby said wheeled frame supports said lifting frame when said lifting frame is lowered thereafter.

3. In a liftvtruck of the classdescribed, a main frame, a Wheeled supporting frame for said main frame normally under said main frame, a for wardly extending load lifting frame, .means mounting said lifting frame for movement relatively to said main frame, means for elevating said load lifting frame relatively to said main frame, a presser foot for said lifting frame, means whereby the said presser foot assumes a load imposed on said lifting frame and moves against the ground in supporting relation to said lifting frame when a load is applied to said lifting frame and lifted, said wheeled supporting frame being thus relieved of the weight of said main and load lifting frames, and means whereby said wheeled frame is moved under-said load lifting frame whereby to support said lifting frame independently of said presser foot when said liftingframe is lowered thereafter.

4. In a' lift truck of the class described, a main frame, a load -lifting frame, means for velevating said load lifting frame relatively to said main frame, means mounting said lifting frame 'for lifting movement relatively to said main frame, a presser foot for said lifting frame, means whereby said presser foot assumes a load imposed on said lifting frame and moves against the l ground in supporting relation to said lifting frame whereby to support a load on said lifting against the ground in supporting relation to said lifting frame, means whereby said lifting means separate said load lifting frame from said presser foot whereby to lift said lifting frame, and Wheels carried by said main frame movable under said lifting frame when said frame is elevated, whereby to assume the load and relieve said presser foot therefrom.

6. In a lift truck of the class described, a main frame. a load lifting frame, lifting means on said main frame for elevating said load lifting frame, a presser foot for assuming substantially the load and the weight of said load lifting frame when the said frame is elevatedby said lifting means,

means whereby said presser foot is maintained spaced from the ground when said lifting frame is not in load assuming position, and means whereby said presser foot moves against the ground upon the assumption of a load .by said lifting frame.y

7. In a lift truck of the classdescribed, a relatively short main frame, Wheels supporting said frame, lifting forks pivoted to said main frame at its forward end, a presser foot also pivoted to said main frame at its forward end, lifting means carried by said main frame and so connected to said presser foot and said lifting forks as t'o separate said presser foot and lifting forks when operated, for lifting said forks through said presser foot, a

. spring, means whereby said spring holds said lifting forks and said presser foot in an elevated po-I 'sition until a load is applied to said forks whereforward` end, a load lifting frame adapted to be elevated relatively to said presser foot and said main frame, liftingfmeans so connected to said presser foot and load lifting frame as to separate them when operated andthus elevate the load liftingframe through said presser foot, whereby when a load is applied to said lifting frame and said lifting means are actuated, said presser foot is forced against the ground and thereafter Supports the load lifting frame as said frame is separated from said presser foot.

9. In a lift truck ofthe class described, a main iframe,- wheels supporting said frame, a presser foot pivoted relatively to said main frame' at its forward end, a load lifting frame supported by and adapted to be elevated relatively to said presser foot and said main frame, lifting means so connected to said presser foot and load lifting frame as to separate them when operated and thus elevate the load lifting frame through said presser foot. whereby when a load is applied to said lifting frame and said lifting means are acmain frame at its forward end, a load lifting v tuated said presser footis forced against the ground and thereafter supports the load lifting frame as said frame is separated from said presser foot, and a spring for maintaining said load lifting frame and presser foot in an elevated position until a load is applied toV said frame suillcient to force the presser foot against the ground in opposition to said spring.

10. In a lift truck of the class' described, a

main frame, wheels supporting said frame, av

presser foot pivoted relatively to said main frame at its forward end, a load lifting frame adapted to be elevated relatively to said presser foot and said main frame, lifting means carried by said main frame and so connected to said presser foot and load lifting frame as to separate them when operated and thus elevate the load lifting frame through said presser foot; whereby when a load is applied to said lifting frame and said lifting means are actuated said presser foot is forced against the ground and thereafter supports the load lifting frame as said frame is separated from said presser foot, supporting wheels normally mounted under the main frame of said truck, means for moving said wheels under the load `lifting frame when said frame is elevated to a predetermined position relatively to the presser foot then maintainedagainst the ground, and means movable with said wheels and on which said load lifting frame may then be lowered to apply the load to said wheels and remove it from saidpresser foot.

11. In a lift truck of the'class described, arelatively short mainv frame, wheels supporting said frame, a presser foot pivoted relatively to said frame adapted to be elevated relatively to said presser foot and said main frame. lifting meansI carried by said main frame and so connected to said presser foot and load lifting frame as to sep,

arate them when operated and elevate the load lifting frame through said presser foot, whereby for moving said wheels under the load lifting frame when said frame is elevated to apredetermined position relatively to said presser foot then maintained against the ground, and means movable with said Wheels and on which said loadl lifting frame may then be lowered to apply the load to said wheels and remove itl from said presser foot so that said presser foot is lifted oil.' the ground by said spring means to permit the truck to be moved to transport the load.

12. In a lift truck of the class described, a relatively short main frame, lifting forks pivoted to said main frame at its forward end, a presser foot also pivoted to said main frame at its forward end,liftingm'eansl carried by said main frame and so kconnected to said presser foot and said lifting forks as to ,separate them when operated and thus lift the said forks through said presser foot, a spring, means whereby said spring holds said lifting forks and said presser foot in an elevated position until a, load is applied to said forks whereupon said presser foot is forced against the ground and thereafter supports the load lifting forks as said forks are separated from said presser foot by actuation of said lifting means, supporting Wheels normally mounted under the short main frame of said truck, l means for moving said wheels under the load lifting forks when said f forks are' elevated to a predetermined position relatively to the presser foot then maintained against the ground. and means movable with said wheels and on which said liftingl fprks may then be lowered to apply the load to said wheels and remove it from said presser foot so that said presser foot is lifted oi! the ground by said spring means to permit the truck to be moved to transport the load. l

`13. In a lift truck of the class described, a

relatively short mainframe, a presser foot plv-,l

oted to said main frame at it's forward end, a load lifting frame adapted to be elevated relatively to said presser foot and said main frame, lifting means carried by said` main frame and so connected to said presser foot and load lifting frame' as to separate them when operated and elevate the load lifting frame through said presser foot, 'whereby when a load is applied to said lifting frame and said lifting meansare actuated said presser foot is forced jagainst the ground and thereafter supports the load lifting frame as said frame is separated from said presser foot, supporting wheels normally mounted under the' short main frame of said truck, means for moving said wheels under the loadlifting frame when said frame is elevatedto a predetermined position relatively to the presserl foot then maintained against the ground, means movable with said' wheels on which said loadlifting frame may then be lowered to apply'the load .to said wheels and remove it from said presser foot, and means on said presser foot for stabilizing said wheels.

14. In a lift truck of the class described, a

` relatively short main frame, wheelsv supporting said frameat its rear end, wheels supporting said frame at its forward end, apresser foot pivoted to said main frame at its forward end, a load lifting frame adapted to be elevated relatively to said presser foot and said 'main frame, lifting means carried by said main traine and so oonneeted to said presser foot and load lifting frame as to separate them when operated and thus elevate the load lifting frame through said presser foot, whereby when a load is applied to said lifting frame andvsaid lifting means are actuated saidpresserfootisforoedaglinstthesrwndmd thereafter supports the load lifting frame as said lifting frame is separated from said presser foot, means whereby continuous operation of said lifting means lifts the main frame also relatively to on which said load lifting frame may then be lowered to apply the load to said wheels and remove it from said presser foot.

15. In a lift truck of the class described, a relatively short main frame, wheels supporting` said frame at its' rear end, wheels supporting said frame at its forward end, a presser foot pivoted to said main frame at its forward end, a load lifting frame adapted to be elevated relatively to said presser foot and said main frame, lifting means carried by said main frame and so connected to said presser foot and load lifting frame as to separate them when operated and elevate the load lifting frame through said presser foot, whereby when a load is applied to said lifting frame and said lifting means are actuated said presser foot is forced against the ground and thereafter supports the load lifting frame as said lifting frame is separated from said presser foot, means whereby continuous operation of said lifting means lifts the main frame also relatively to said presser foot so as to relieve the wheels at the forward end of any load, a, spring for maintaining said load lifting frame and presser foot in an elevated position until a load is applied to said frame sufficient to force the presser foot against the ground in opposition to said spring, means for moving said wheels at the forward end under the load lifting forks when said forks and said main frame are elevated to a predetermined position relatively to the presser foot then maintained against the ground, means movable 4with said wheels and on which said load lifting frame may then be lowered to apply the load to said wheels and remove it from said presser foot so that said presser foot is lifted oif the ground by said spring means to permit the truck to be moved to transport the load.

16. In a lift truck of the class described, a main frame, rear supporting wheels on said main frame, forward supporting wheels for said frame movable laterally relatively thereto, said frame resting normally on means supported by said wheels, means for lifting the main frame so as 4[to relieve the forward supporting wheels of the weight thereof, and means for then moving said wheels laterally relatively to said main frame to change the truck wheel base.

1'7. In a ,lift truck of the class described, a

vmain frame, a load lifting frame, lifting means for elevating said load lifting frame, a presser foot for said load lifting frame, means whereby the lifting means separates said presser foot from said load lifting frame and forces said foot -against the ground to support said load lifting' frame for elevating movement by said lifting means, supporting wheels for the main frame of said truck relieved of the load of said main and lifting frames by the action of said presser foot,

18. In a lift truck of the class described, 'a main frame, a load lifting frame, lifting means on said main framje for elevating said load lifting frame, a presser foot for said load lifting frame, means whereby the lifting means separates said presser foot from said vload lifting frame and forces said foot against the ground to support said load lifting frame for elevating movement by said lifting means, supporting wheels for the main frame of said truck, meansrfor moving said wheels to a point under the load lifting frame when said load lifting frame is elevated relatively to said presser foot, and means supported by said moving wheels for taking the load of said lifting frame when said frame is lowered from an elevated position relatively to said presser foot.

19. In a lift truck ofthe class described, a main frame, a load lifting frame', lifting means on said main frame for elevating said load lifting frame, a presser foot for said load lifting frame,

by said lifting means, and a fluid check between said presser foot and load liftingframe for ab: sorbing the downward movement of said load lifting frame.

20. lIn a lift truck of the class described, a main frame, a presser foot and load lifting frame supported through said main frame, lifting mechanism of the type operated by a lifting lever carried by said main frame, means whereby said lifting mechanism is inter-connected between said presser foot and said load lifting frame for vlifting said load lifting frame by separating it from said presser foot while said presser foot is maintained against the ground. i

21. In a lift truck of the class described, a main frame, a presser foot and load lifting frame supported through said main frame, a spring for maintaining said load lifting frame and presser foot in a predetermined position with the presser foot oi the ground, said presser foot being movable against the ground in opposition to said spring when a load. is applied to said load lifting frame, lifting mechanism of the type operated by a lifting lever carried by said main frame, means whereby said lifting mechanism is interconnected between said presser foot and'said lead lifting frame (for lifting said load lifting frame by separating it from said presser foot while said presser foot is maintained against the ground.

22. In a lift truck of the class described, a main frame, rear supporting wheels for said main frame, forward supporting wheels for said main frame mountedfor longitudinal movement relatively to said main frame when said wheels are relieved of the load of said main fram'e whereby to change the wheel base lof the truck, and lifting means for soirelieving the said forward supporting. wheels of the weight of said main frame.

23. -In a .lift truck ofthe class described, a main 4frame, rear supporting wheels for said main relieved of the load of said main frame whereby to change the wheel base of the truck, a lifting frame overhanging the forwardend of the truck, and means for lifting said lifting frame together with said main frame relatively to said forward supporting wheels whereby'to so relieve the said wheels of the weight of said main frame.y

24. In a lift truck of the class described, a main framef'rear supporting wheels for` said mainframe, forward supporting wheels for said main frame'mounted for longitudinal movement relatively to said main frame when said wheels are relieved of the load of said mainframe whereby to change the wheel base of the truck, a lifting frame overhanging the forward end'of the truck, means for lifting said lifting frame together with said main frame relatively to said forward supporting wheels whereby to so relieve the said wheels of the weight 'of said main frame. and means for moving said wheels longitudinally thereafter under the said overhanging lifting frame to support the said lifting frame when it is lowered by saidlifting means.

25. In a lift truck of the class described, a main frame, rear supporting wheels for said main frame, forward supporting wheels for said main frame mounted for longitudinal movement relatively to said main frame when said wheels are relieved of the load of said main frame whereby to change the wheel base of the truck, and lifting means engaging the ground for so relieving the said forward supporting wheels of the weight of said main frame.

26. In a lift truck of the class described, a

`main frame, rear supporting wheels for said mainframe, forward supporting wheels for said main frame mounted for longitudinal movement relatively to said main frame vwhen said wheels are relieved of the load of said main frame whereby to change the wheel base of the truck, a lifting frame overhanging the forward end of the truck, means engaging the ground for lifting said lifting frame together with said main frame relatively to said forward supporting wheels whereby to so relieve the said wheels of the weight of said -main frame, and meansi for moving said wheels longitudinally thereafter under the said overhanging lifting frame to support the said lifting frame when it is lowered by said lifting means.

GEORGE QUAYLE.