US2309138A - Lift truck - Google Patents

Description

Jan. 26, 1943.l G. QUAYLE 2,309,133

LIFT TRUCK FledeJuly 25, 1940 6 Sleets-Sheet 1 mmn.

l ATTORN EY ,Janv 26, 1943 y G. QUAYLE 2,309,138 LIFTv TRUCK a Filed July 25, 1940 6 Sheets-Sheet 2 Jan. 26, 1943. G, QUAYLE y 2,309,138

/ 45 ATTORN EY 6 Sheets-Sheet 4 INVENTOR Bywf @'74 ATTORNEY Jan. 2.6, 1943.

G. QUAYLE 2,309,138

LIFT TRUCK 6 Sheets-Sheet 5 ATTORNEY Jan@ 26, 1943. f G. QUAYLE 24,309,133

LIFT TRUCK Filed July 25 1940 6- Shee'cs-SheeiI 6 ATTORNEY Patented Jan. 26, 1943 UNITED f STAT Es PATENT y 'Lm'r 'muck l George-Quayle, Philadelphia, Pa..V assignor to The .Yale & Towne Manufacturing Company, Stamford, Conn., a corporationof Connecticut v Application July 25, 1940, seriaiNo. 347,466

j (ci. 25a-z)- 19 claims.

swinging ofthe usual steering handle, it being.

a feature ofmyinvention that the handle may operate the hydraulic mechanism in all steering partscutl away tobetter expose .others ofthe parts. is a side view of the truck of Fig. 1 with some of the parts cut -away to better illusi trate the operation oi others of the parts. Fig. 3

is a View tak'enalong lines 3-3 of Figs. 2 and 10. Y

., Fig. 4 isa perspective view of certain of ther parts showniin Fig. A3. gFigs..5 andare sections "taken,

substaitiauyalong unes 5.-5 and s-.s of Fig. 3.

positions thereof,jIn asecond modification, I

utilize a depressible pedal mechanism for-oper ating the hydraulic `mechanis`m,it being a feature. of my inventionthat the hydraulicmechanism is so constructed that itis readily mounted between the lifting head and the lifting platform for lifting the said platform, while but slight change of 7 is aview ofcertain of. the parts ofFig. 6 in another position.` Figs. 8- and .9 are sections I along lines and 9-9 respectivelyof Fig. 6. f Fig. 10 is a view along lines Ill-'I0 of Fig.3. Figs. 1l and l2 are enlargedlviews of kparte `of Fig. 10

in otheli-operating positions Fig. 13 is a'view" vofthe'front ofthe truckof; Figs. 1 and 2, yshowing that truck adapted for pedal operation.y Fig. l141 is a horizontal sectionk through theghydraulic mechanism of Fig: 13 illustrating the relation of certain parts of the truck are required to adapt;

the truck for pedal or handlevoperation. Y

A further feature of the invention is the par- 'ticular mounting of the .hydraulic mechanism,

and the means whereby movementis transmitted I therefrom to the lifting platform. More in detail, this -feature ofthe'invention utilizesmechathe various portions of thehydraulic mechanism vand lthe mounting of the foottreadles. Fig. 15

I is a View4 similar to Fig.3 ofthe first modiflcation and showing amodied formof hydraulic mechae' nism. Fig.y 1651s. a section taken '.alongflines nism whereby the platformmay moverelatively.

to the ram of the'hydraulic mechanism'without affecting the mounting or the operation of thel ram. Those skilled inthe art will appreciatek the importance of this construction, since liftally do have somemovement which it is undesirable should be transmitted'to the hydraulic meching platforms of the type described by me naturanism and the mounting meansof the hydraulic mechanism.

I have attempted tolset forthgenerally the more important features of my invention,'but a reading of the specification which follows will indicate' that. there are a 4considerable number of additional features which are of great importance vand'which form valuable'p'ortions of my contribution to the art. vThese additional `features, together with those alreadydiscussed, will of course be set forth in the claims-hereinafter. it being further understood, moreover,l that the .patent claims which I expect to obtain should be of such a character as Lto prevent the' utilization of my contribution yto the art in specific forms other than those which I show anddescribein this application. Y

For adescriptionvof my invention, I shallrefer lsv-IBOFSZ-ll f f I shall now refer to Figsfl and! withLreference -to which I shall presentan outline of my truck construction.vr Y Thereafter, the details thereof will be described with reference to the remaininggures aswellasto Figs. l and2. My truck comprises whatl choose to call a lifting head I0, relatively'to, which is pivotally secured `what I term a lifting platform I I, the lifting platform II `having a front. vertical standard I2 against which operates .the `thrust pin'lof a hydraulic ram forming part of the hydraulic lifting assembly I I.

This hydraulic uiting assembly is actuated through. means of a pivoting lever I5 by vertical swinging movement of the steeringkhandle AIi connected to the lever Ili'by a vertical-strut I'I.

' The steering handle I6 operatesthe lifting mechanism, and also. steers the front steering wheels to the drawingsjw'herein Fig. 1 is a plan view v looking downwardly on my truck, with'certain I8 of the truck. as lwill `be understood by those skilled in .the art. 'I'he rear wheels-.Il of the truckr are adaptedV for lifting movement'relativ ly to the platform .II ,whereby'the'.lea'rl end of the platformis elevated vat the same time that the front end carrying the vertical` standard I2 k `elevated. '1

Y Referring now more particularly to Fig. `l0, I shall first describe the liftingV head Ill cfm,

. f truck. This lifting head has mounted for'rotav tion .relatively thereto'the wheel supporting fort;

y2li, in which lare mounted the front" wheels II already described. .The 'forks 20 form part'ot what I term a steering head 2|, which is rotatable relatively to the lifting head through means of the roller bearings 22 and the sleeve bearing 23. Pinned to the steering head 2| as at 24, and forming part of the steering head 2|, is a collar 25, relatively to which is supported the lower main casting I Sa of the steering and lifting handle IB through means of the pin 21. rod 28 extending from the steering handle casting |611 is pivoted at 29 to the collar 25 and forms part of the spring balancing mechanism for that handie, a construction which is not new in this application and need not be described therefore.

Formed as part of the handle casting |6a and movable integrally therewith is a pin 3|, relatively to which is secured the strut I1 terminating in a ball 33 resting in a ball socket of ythe actuating pivoted lever i5, already described. The main portion of this lever I Vis substantially triangular in form, as can best be seen in Fg. l, and has formed as partthereof a sleeve 34 whereby it is secured for rotation about a shaft 35 carried in bearings 36 formed in each of the two upwardly `extending standards 31 of the lifting head l0, as is probably best seen in Figs. 2, 3 and 10.

The actuating lever I5 has formed also, as a portion thereof, an arm 33 which is forked at its end as at 39 and 40 for the mounting of a roller 4|. 'I'his roller is utilized to actuatethe pump of the hydraulic mechanism in a-manner to be indicated later. It is obvious, vof course, from the construction so far described. that the lifting and steering handle I6 is rotatable together with the steering head 2| to steer the truck, and that the handle il and its casting Ita may be swimg vertically to operate the strut to rotate the actuating lever |5 about the shaft 35, so as to force the roller 4| upwardly and downwardly to operate the pumping mechanism. It is further obviousto those skilled in the art that the strut lies substantially in the axis of the steering head 2|, and that through its ball end 33 operating in the ball socket ofthe actuating. lever i5, the handie I 5 may be utilized for lifting operation in any of its'steering positions.

As is probably best seen in Figs. 2, 3 and 10, the lifting head has a downwardly'and somewhat rearrlvardly` extending portion 42 at each side thereof, within which are formed bearings for the mounting of a shaft 43. Right and left hand front lifting links 44 are adapted for mounting at the right hand and left hand ends of the shaft 43 just inwardly of the lifting head portions 42 for rotation on the said shaft. Each of these links has a. bearing portion 45 (Fig. 5) whereby it is secured about a shaft 46 supported at each side of the lifting platform at points near the front end of that platform, as is quite apparent from Figs. 2 and 10.

Referring now again to F18. 5, each of ythe links 44 is shown as bifurcated at one end, forming bearings 41 for a pin 48, whereby each of the links. is pivotally secured toa threaded rod connector 49. Each of therod connectors 49 is threaded for the entry of a rod 5| which is secured thereto in adjustedthreaded relationsby a locking nut 59. As is best seen in Fig. 2, each rod 5| extends to the rear of the truckwhere it is secured to a second rod connector 52 in the same manner as it is secured to connectors 49.

.Each of the rod connectors 52 is in turn secured the platform frame and support the rear load wheels |9.

It is now obvious that should the front vertical standard I2 of lifting platform be moved vertically relatively to the lifting head l0, through the functioning of linkage and operating means not yet described, the shaft 46 on which are mounted the links 44 through their bearings 45, will cause the links 44 to rotate clockwise in Fig. 2 relatively to shaft 43 of the lifting head. This will cause the rods 5| to move to the right. thereby swinging the rear links 55 downwardly relatively to the lifting platform il, effecting the movement of the lifting platform in a vertical direction .to the position shown in dash and dot lines inFlg. 2.

t shown in dash and dot lines. It will be noted that the eiect of the movement of the wheels in Fig. 2 is to lengthen the wheel base of the truck, and as a matter of fact, there will be a tendency for the entire truck to move forward, as is illus- Itrated by the dash and dotlines of the front wheels I8 in Fig. 2. 'I'he advantage of the particular construction is that a load on the lifting platform Vwill be moved away from the wall against which it may be `stacked as the platform is elevated. Theeiectiveness of the construction will be particularly clear to those skilled in the art.

For imparting lifting movement to the lifting platform ||,as just outlined, I utilize a hydraulic lifting assembly, which I have already indicated generally by reference numeral i4, and which includes as part thereof a uhydraulic ram having a rounded pin |3 for imparting lifting thrust to thev vertical standard |2 of the lifting platform. This hydraulic lifting assembly, which is best shown generally in Figs. 3 and l0, has a main base portion 5l from which extend ears 56 whereby the base portion, and therefore the entire hydraulic assembly, is secured for pivotal movement relatively to the shaft 43 already described as supported by the extensions 42 of the lifting head i0. The base 5l extends upwardly and to each side to form a relatively large reser- Avoir chamber 58 as defined by an outer wall 59.

' ram being of any type well known in the art,

and carrying a series of piston rings 65, as will be readily appreciated by those skilled in the art.

A pair of cover plates 66 and 61 are secured to the upper peripheral edge of the wall 59, whereby to completely enclose the reservoir 55.

f as best seen in Figs. 3 and 10. The cover plates 66 and 61 allow for the extension of the cylinders G2 and 63 therethrough, suitable sealing means being provided for sealing the openings through which the cylinders protrude, all as will be understood =by those skilled in the art.

l che Ibeamsr1s.

a'soaiss .A pair of telescoping'compression springs 13 surround the pump rod 88 and lie between a` washer 13a and the collar'69 whereby to.urge

pump rod 68 upwardly so as to .bring the cap 18 against the pump actuatingroller 4I. The

springs serve to press the cap against the roller f 4I, thereby pressing the roller 4| and the actuating lever 5 in a counter clockwise direction, as viewed in Fig. 18, and thereby bringing theY ball socket of the actuating'levex'" I5 against the ball end 33 of the strutA I1 so as to' take `up any Y lost motion between the several al1 as will bev quite apparent.

The ram 64 carries at the upper end thereof the rounded pin I3, which has already been described, and which operatesgin a cooperating depression 14 formed within a block 15 Which is secured as by welding or in any other manner, to parallel beams 16. The beams'16 have mounted between them vand on each 'end thereof a roller 11 as best seen'in Fig. 4,'the rollers 11 the vertical standard will move freely transversely relatively to thev two rollers11. Moreover, any circular or twisting movement of the elevatingv standard `I2, even if it should tend to rotate thebeams 18 through rollers 11, will f not be transferred to the hydraulic mechanism due to the relationship of the rounded pin I3 and the `socket 14 of the block 15 carried by lifting head which can -be compensated for by the roller 4I operating against the cap 18 of pump rod'58. v

There is of course a suitable stuiiing box between the end of the hydraulc ram 64 and the cylinder 63 in which vit is mounted, all as is well f understood by those skilled in the art. For protecting the hydraulic ram, Iemploy a, skirt 19 secured to the end of the ram through a. cap 88, with the said skirt surrounding the -outer i wall of the cylinder 63. As thehydraulic ram moves vertically from Fig. 3 to liftV theplatform, it is of course obvious that the skirt 19 will maintain covered the end of the ram at all times, thereby protectingit against picking up abrasive material and carrying it back into the cylinder 63. The skirt 1| of vcap 18 of the pump rod 68 has a like function.

There was described earlier the linkage whereby the lower end of the platform II is mounted relatively to the lifting head I8. It will now be i well to indicate that the upper lend of the vertical standard I2 of the lifting platform is also secured by linkage to the lifting head l0.A Thus, welded Naturally, longitudinal move- 'ment of the yplatform will simply cause a slight or otherwise secured to vertical standard I2 are spaced plates 8 I, between which is supported a v.shaft 82 (Figs. l and l0). A substantially H- shaped lever 8 3, best shown in Fig. 1, is equipped 5- with a sleeve portion 84 at one end thereof whereby it is secured aboutthe kshaft 82. At its other end, the H-shaped lever -83 has formed thereon a sleeve portion 85 whereby it is secured relatively to a-shaft 86 carried in bearings 86a at theupper end 31 of the lifting head I8. ,It is the function of the lever 83 to guide the upper end 1 of the kvertical standard `I2 in its movementrelatively to the lifting head, just asthe lower links 44 guidethe lower end of the standard and the platform II in theirelevating movement.

Referring now to Figs. 3, 5 and 6, I shall describe the variouspassages formedA within the base/ 51 ofthe `hydraulic mechanism, and the valvesk positioned relatively to those passages gowhereby the operation of the hydraulic mechanisrm will be understood. A longitudinally extendingmainvalve bore 81, 88 is formed in the base 51 inclined somewhat relatively to the Ahorizontal. as best shown in Fig. 6. Thisrnain valve .25 bore includes a bore 81 and 4afurtherb'ore 88, the two bores being coaxial. The valve Ibore 81, yIl8is closedvat one end through the screw threaded cap 89'holding in place the gasket 98all as is best seen in Figs. 3 and 6. Theopposite end is closedby a threaded plug |85. Y

Mounted'within the -bore 81 is avalve9| havl-ing a series of holes 92 drilled therethrough, as is best illustrated in section in Fig. 9. This valve is formed to cooperate with a seat 93 at the. left handend of the bore 81. A plug 9 4 ismou'nted within the bore 88, and itselfhas a bore 95 therethrough forming a valve passage for cooperation tively to a-valve seat 91 formed on the plug 94, and is held againts this seat by a spring 98, as is readily seen.v A spring 99 lies between theplug 94 and the valve 9| to maintainthe valve 9|y normally against its seat 93.

A-passage |88 leads through base 51jintothe valve bore 81 from the reservoir chamber 58, while Aa bore I8I .leads tothe valve bore 88 from the pump cylinder 62, as can be seen by reference to Figs. 3, 5-and 6, the bore `I8| `communicating .with the. cylinder 62 through the bore |82. Through bores Y |83 and |84,l commimication is established between the ram cylinder 63 and the extremeleft hand end of the main valve @bore which is to the left `of the valve 98. Thus. it may bev said that in Fig. l6 the right end of its piston, pressure against the end of thevalve away from its seat at 93'against the force of spring'99 so that uid will flow from the passage f |88 through the holes 92 of the stem of valve 8| andthrough the passages I8I, |82 into the pump. At the beginning of the downward pumping stroke, the valve 9| will become seated at 93', and all of the pump pressure will be introduced against the end of the valve 96. 'I'his will unseat valve 96 relatively to its seat at`91 and against the resistance of spring 98, whereby to force the fluid through the passages |84 and |83 in to the 75 cam cylinder 63, whereby to' move the ramv 64 with'a valve 96. The valve 96 y.is seated rela- `valve bore 81, 88 communicates with thereser- 9| will vnaturally berelieved, whereby to move it' vertically to lift the platform. 'I'hrough a series of strokes. the ram will be moved to its completely elevated position.

If now it is desired to lower the load, utilization is made of a cam operating shaft |06 and its cam surface |01. It will be notedthat the cam operating shaft |06 is mounted within a transverse bore |08 formed in the base 51, as best illustrated in Figs. 5 and 6, the shaft extending outwardly of the base 51 through a suitable stuiling box- |09. 'I'here will be described later the mechanisms which are mounted on the shaft |06 for operating that shaft and for controlling its movement. Sufllce it to say at this time that when the shaft |06 is rotated in a counter clockwise direction to position F, as seen in Fig. 6, its surface |01 .will move the valve 9| oif its seat at 93, so as to establish low pressure communication between the pump and the reservoir 56 through passages |00, |02. Thereafter, p and down movement of the pump will have no affect whatsoever on the pumping mechanism, since it will be impossible to generate suillcient pressure to Amove the valve 96 off its seat at 91, as is necessary when it is desired to admit uid under pressure to the hydraulic ram. In this position of the parts, there will be hadk what is known in the art as a free operating handle, and which is obtained usually in mechanical structures by simply releasing the operating mechanism from the vertically swinging handle.

If in the position of the partsdescribed, it is.

desired to lower the truck lplatform l, rod |06 is rotated further carrying cam surface |01 past the position of Fig. 7 to the position L shown in Fig. 6. 'Ihis rotation of rod |06 will bring the left lhand end of the valve 9| against the right hand end of the valve 96, moving that valve off its sat at 91. Communication will then be established between the ram and the reservoir 59 through the valve passage 95, the open valve seat Il, and the bores of valve 9| wherebyto effect the lowering of the load platform.

Those skilled in the art will fully appreciate that the initial withdrawal of the valve 96 from its seat at 91, especially with a heavy load o'n the ram, will cause an extremely swift movement of a small quantity of fluid past the valve seat 91. This extremely swift movement of fluid will gradually wear away the valve seat under the usual operating conditions.- Therefore, I have arranged means whereby there is substantial-1y no flow of fluid past the valve seat 91 until the valve Il has beeny moved oil its seat a sulcient distance to present a relatively large opening. The flow of fluid is then' in relatively large volume, and as `will be understood by those skilled in the art, the

speed of the flow of the duid wil-1 be considerably reduced.

A is best shown in Figs. 6, '1 and 8, the valve plug is counter bored at 94a to present a somewhat larger flow opening than the remainder of valve bore 95. The valve stem of valve 96 has a necked portion 96a which is normally opposite counter bore 94a and is defined at one end by a shouldered portion ||0 which, in the normal position of the parts in Fig. 6, fully closes the bore 95 within which the valve $6 is adapted to slide. Extending from this surface ||0 in valve 96 is a gradually tapered groove shown in section in Fig. 8, the groove ||I being entirely eliminated at the shouldered surface |0.

Because of this relation of the parts, it is readily seen that even if the valve 96 is moved off its seat 91 toward the position of Fig. 7, there still will be very little now past the seat 91 because the surface ||0 of the valve maintains substantially closed theV valvebore 95. It is only after the valve 96 has been moved for a considerable distance, and somewhat further thanshown in Fig. 7, whereby to space it from its seat 91 an appreciable amount, that the surface ||0 is moved sufiiciently out of the main portion of the bore 95 and opposite the counterbore 94a to expose part of the groove of the valve stem. An appreciable amount of :duid maythen begin its flow past the valve seat 91, and at a speed which is comparatively low, so that the worst possible wear condition no longer exists. It is well to indicate that the groove acts to control the platform lowering 'speed. that speed being in- 4creased as the valve 96 is moved to the left in Figs. 6 and '1 to expose the deeper portion of the srooveto the fluid.

Referring now once again especially to Figs.

3, 5, 11 and 12, the end of the valve control rod |06 has secured thereto the foot treadle ill v through its sleeve portion ||6 and cotter pin ||6a, whereby the treadle will rotate the rod |06 to control the valve mechanism, as previously described.

Rotating withthe treadle H5 and its sleeve I|6 are a pair of ears ||1 carrying a pin H6. Mounted on this pin H0 through bifurcated legs ||9 is a cam piece |20. This cam piece |20 has secured thereto a rod |2I which slides at its upper end in holes` |22 formed in the cover plates 66 and 61 -of the reservoir 50. A spring |23 surrounds the-rod |2| and bears between the lower cover plate 61 and the upper surface of the cam |20, whereby through the pin |I8, it tends to rotate the treadle in a clockwise direction, looking' at Figs. ll, 12 and 13, and to maintain the valve control rod |06 in its full line position of Fig. 6. In this position of the parts, lifting movement of the hydraulic mechanism will be effected by the pumping action of the steering handle I6.

Movable also integrally with the treadle ||5 is the roller |25 which, in the normal position of the parts, that is, in the position of Figs. 5, 6 and l0, lies within a depression or cam surface |26 formed on the cam piece |20. It will of course be appreciated that the relation of the roller and cam surface may easily lbe reversed and that other cooperating parts may be used. With the truck platform in any particular elevated position, should it be desired to obtain a free handle by the moving of the valve control rod |06 and its cam surface |01 to the position F in Fig. 6. as already described, the operator steps on the treadle I5 and moves that treadle from the Dosition of Fig. 10 to the position of Fig. 11 against the resistance of spring |23, whereby to move the roller |25 outv of the depression or cam surface |26 tovthe position of Fig. 11. In this position of the parts, the spring |23 will tend. of course, to rotate the roller |25 and the treadle |I5 back to the position of Fig. 10 but the surface |21 coopertating with the roller will prevent such movemen If, in this position of the parts, it is now desired to rotate the valve control rod |06 to the position L in Fig. 6, whereby to release the load by the movement of the valve stem 96 off its seat as in Fig. 7, the operator will move the pedal H5 to the position of Fig. l2, thereby compressing the spring |23 even more than previously. Natural- 1y, in this position of the parts, the ram and plat-l The operator now has a choice of two actions. If he wishes to have a free handle so that the truck may be hauled about, he may return the treadle slowly to the position of Fig. 11 where it is stopped by roller |25 striking surface |21. In this position of pedal ||5, the valve 8| will be maintained off its seat at 83 and free communication is had between the pump and reservoir to yield the free handle desired. On the other hand, if the operator wishes to place the valve mechanism in its initial position of Fig. 6 so that operation of the lifting handle will elevate the truck platform, he has only to release the treadle vin the position of Fig. 12 to allow the full action of the spring |23. The spring |23 will, in its then state of compression. rotate the treadle ||5 rather swiftly towards the position of Fig. 11.

I The speed of movement is such that the surface |21 will be incapable of preventing the movement of the roller |25 back into the depression |20, as shown in full lines in Fig. l0. Therefore, the treadle will return to its initial position of Fig. 10. all as is quite apparent.

Also mounted for movement with the treadle ||5 is a cam |28, the purpose of which will now be described. Referring also to Figs. 3, 5 and 10, it will be noted that the left hand front lifting link 44 has mounted thereon an adjustable screw bolt |28. It is the function of this bolt when the platform is in a fully elevated or other predetermined position, to strike the cam |28 so as to move the treadle from its position of Fig'. l0 to the position of Fig. 11. 'I'he purpose of this action is to present a free handle immediately upon the elevation of the load platform to a predetermined position. This predetermined position may be varied, of course. by an adjustment of the bolt |28, all as is quite apparent,

Referring now to Figs. 13, 14 and 15,Ishow there certain modifications of my structures already described. The first modification includes means whereby a foot operated treadle |30 is adapted to operate the pump mechanism. Instead of utilizing the type of actuating lever I5 shown in Fig. 10, I utilize a short form of lever, designated by reference numeral 5a, pivoted on shaft 35a in a manner similar to the pivoting of the lever l5 on the shaft 35 carried -by the portion 31 of the lifting head i in the first modification.

It will be recalled that the actuating lever l of the first modification has extending therefrom but a single lever arm 38, on which is mounted the roller 4|. In the modification of Figs. 13, 14 and 15, the lever |5a has two extending arms, designated in the drawings by reference numeral 38a, but only one of these arms is bifurcated for the mounting of a roller 4|a for operating the pump piston, as best shown in Figs. 13 and 15. Each of the arms 38a carries a short shaft |3| whereby connection is made to vertical struts |32, which at their lower ends are pivoted at |33 to the foot treadles |30. The roller 4 la is mounted on the shaft |3| carried by the right arm 38a in Fig. 15. As is apparent from Fig. 14, the foot treadles |30 are mounted at each side of the lifting head, and are connected by a transverse bar |3| so that the pump may be actuated from the right or left hand of the truck, depending on which is most convenient in any particular posi tion of the truck. 'I'he foot treadles |30 are mounted for pivoting movement about a shaft 43a, which is positioned exactly as is the shaft 43 of the first modification. By comparing Figs. 3 and 15, it will be seen that shaft 43a is simply slightly longer than shaft 43 in order 'to support thereon the treadles |30, which treadles are of course not required in the modification of Fig. 3. The shaft 43a. just as does the shaft 43, supports the links 44 and the .basev 51 of the hydraulic mechanism through the ears 58 thereof.

A further variation from the modification of Fig. 3 is in the securing of spring brackets |34 to the side extensions 42 of the lifting head. These spring brackets |34 support the ends of springs |35, which at their other ends are secured at |38 to the treadles |30 whereby to somewhat balance the weight of those treadles, thereby assisting the springs 13 of the pump rod in maintaining the treadles in their normal position.

'I'he hydraulic mechanism shown in Figs. 14, 15 and 16 is modified by the addition of means whereby when the platform is lightly loaded, or not loaded at all, the pumping action will cause a swift elevating movement thereof, While when the platform becomes loaded, the lifting motion thereof will be at a slower rate. In order to accomplish this, the ram mounted within the cylindex' 63 and designated by' reference numeral |31, is bored as at |38 for the mounting therein of a stationary ram utilizing a. piston |38 secured to a sleeve-like rod |40. Rod |40 is threaded as at |4| into the base 51 of the hydraulic mechanism and communicates with passages |03, |04 leading to the main valve bore 81, 38 described with reference to the rst modification. lowered position of the platform, there is preferablya space |42 between the piston |38 of the stationary ram and the block |43 forming the end of the movable ram |31.

A s best seen in Figs. 14 and 16, the lower end of the cylinder 83 in which operates the large movable ram |31, is in communication through a series of holes |45 with a valve passage |48. This passage |48 is in communication with a bore |41, which in turn is in communication with the reservoir 58. The passage |03 whereby fluid is supplied to the stationary and movable rams, communicates through a small opening |48 with the valve passage |46.

Through suitable means which are shown in Fig. 16 and require no description, there is mounted within the valve passage |48, a valve |48, which is spring pressed by a spring |50 off its seat at |5| and in position to maintain closed the opening |48. Communication between the cylinder 83 of the large ram and the reservoir 58 through the three holes |45 is normally malntained when valve |48 is in its position of Fig. 16. In the position of the parts in Figs. 15 and 16, fluid from the pump is first introduced through the bore |04 into the bore |03 and passes up through the tube I 40 into the space |62 between the piston |38 of the small ram and the cap |43 .relatively to the small stationary ram.

of the large ram, whereby to move the large ram movement will of course move the large ram relatively to the small stationary ram. This movement will of course move the large ram relatively .to its cylinder 83, whereupon fluid lls the resulting space in the bottom of cylinder 83, flowing from the reservoir 58 through the hole |41, past the valveseat |5l, and through the several' holes I 45.

When' the load is encountered, or if the load is very heavy, it will be realized that'the pressure will be greatly increasedand will overcome the pressure of spring |50 holding valve |48 against opening |48 whereby to move the valve |48 from In the.

This.

opening |48. As soon as any slight opening occurs at |48, the uid will then exert pressure against the relatively large surface |49a of the valve |49, and will quickly move that valve into its dotted line position of Fig. 16, in which position it becomes seated against seat |I, shutting off communication between the reservoir 58 and the cylinder 63. Fluid then iiows from the pump through the small opening |48 and the bores |45 into the cylinder 63 to actuate the large ram.

summarizing the action of the last modication, it is quite apparent that upon operating movement of the pump, fluid will flow under the control of valves in main valve bore 81, 08 through passages |04 and |03, and up through the tube |40 to separate the large ram from the small stationary rain. As soon as the pressure is developed through the lifting platform encountering the load or through an increase of the load, the valve |40 will be moved within the valve passage |40 to open up communication at |48, |46 and I 45 between the pump and the large ram, whereupon the large ram will be moved at a slow rate `so that it may handle the relatively large load involved.

In the modification of Figs. 14, and 16, it will be appreciated that the valve mechanism whereby the change from the high speed to the low speed operation is made possible, is entirely automatic, and that this mechanismdoes not in any way affect the operation of the control mechanism of Figs. 5 and 6 described earlier. It will be well also to indicate that In Fig. 14, there is shown the relation of the several valve mechanisms of Figs. 5 and 6 to the pump and the ram, and that this relationship of the parts in the modification is the same as in the first structure described herein. The only change in Fig. 14 is the addition of the valve mechanism shown in Fig. '16, but as has already been said, this does not affect the operation of the main valve mechanism in any way. It will also be well to indicate that the main valve mechanism is operated by the foot treadle ||5 in the modification of Fig. 14 in the same manner as in the first structure described.

I should like to emphasize further at this point that a basic feature of my invention is the arrangementof the parts thereof whereby foot or hand operation may be obtained with a minimum of change, and with the main elements of my combination remaining unchanged. 'I'his is in great part due to my utilization of a hydraulic assembly in which the pump, as well as the ram, is merely in thrust engagement with the parts cooperating therewith. This feature makes it possible to arrange for the mounting of the pump actuating means entirely on the lifting head, all as willbe appreciated. It is thought that a further analysis and description of my invention is not necessary, especially since reference .to the claims will further clarify the significance and value of various cooperating parts thereof.

I now claim:

1. In a truck of the class described, a lifting head, an elevating platform, a hydraulic lifting assembly pivoted at its lower end to said lifting head and including a. ram bearing at its upper end against said platform, a rotating steering head in said lifting head, a steering handle secured to said steering head for rotating the same while mounted for vertical swinging movement relatively to id head, a pump included in said hydraulic lif assembly and comprising a asoaiss pump plunger.

2. In a truck of the class described, a lifting' head, an elevating platform, a hydraulic lifting assembly pivoted at'its lower end to said lifting head and including a ram bearing at its upper end against said platform. a rotating steering head in said lifting head, a steering handle secured to said steering head for rotating the same while mounted for vertical swinging movement relatively to said head, a pump included in said hydraulic lifting assembly and comprising a plunger, a lever pivoted on said lifting head and bearing at one end against said pump plunger,

and a universal joint connection between the other end of said lever and said steering handle whereby vertical swinging movement of said steering handle in all steering positions thereof moves said pivoted lever to actuate the pump plunger.

3. In a truck of the class described, a lifting head, an elevating platform, a hydraulic lifting assembly pivoted at its lower end to said lifting head and including a ram bearing at its upper end against said platform, a rotating steering head in said lifting head, a steering handle secured to said steering head for rotating the same while mounted for vertical swinging movement relatively to said head, a pump included in said hydraulic lifting assembly and comprising a plunger, a lever pivoted on said lifting head and bearing at one end against said pump plunger.

the other end of said lever extending substantial- 1y over the axis ofthe steering head, and a vertical strut member bearing at its upper end against said end of the said lever and at its lower end against the steering handle, and movable substantially in the steering axis by vertical swinging movement of said steering handle in all steering positions thereof to move said pivoted lever whereby to actuate said pump.

4. In a truck of the class described, a lifting head, an elevating platform mounted for lifting movement relatively to said lifting head, a hydraulic uiting assembly, means pivoting said assembly at its lower end to said lifting head, a ram extending from said assembly and bearing at its upper end against said platform whereby to impart lifting movement to said platform and to control lowering movement of said platform, a pump included in said hydraulic lifting assembly comprising a plunger. a lever pivoted on said lifting head having a part bearing against a surface of said pump plunger whereby to allow for movement between said plunger and the lever as the hydraulic assembly moves on its pivot when the platformis being elevated, and means for moving said lever to actuate the plunger.

5. In a truck of the class described, 'a lifting head, an elevating platform, a hydraulic lifting assembly, means pivoting said assembly at its lower end to said lifting head, a ram extending from said assembly and bearing at its upper end against said platform whereby to impart lifting movement to said platform and to control lower- T5 ing movement of said platform, a pump included :,aoaise i in said hydraulic lifting assembly comprising a plunger, a lever pivoted on said lifting head, 4a roller mounted at one end of said lever and bearthe upper end of said ram and bearing in aco- Voperating depression of said` thrust accepting ing against vthe upper end of said pump plunger whereby to allow for movementl between the said lifting head whereby the hydraulicliftingl assembly extending between said head and platform receives but slight pivotal movement Vwhile elevating said platform.

v 6. In a truck of the class described, aflifting head, an elevating platform aY hydraulic lifting assembly, 'means pivoting said assembly at its lower end to said lifting head, a`ram extending *fromy saidassembly and bearing at its upper end against said platformwhereby to impart lifting movementto said ,platform and to control lower ing movement ofsaid platform, a'pump included in said hydraulic lifting assembly comprising a plunger, arlever pivoted on said liftingy head, and bearing at'one end against said pump plunger in all positions thereof, means for moving said lever to operate the plunger, and means mounting, said platform for elevatingmovement relativelyto said tendingbetween said head and'platform receives but, slight -pivotal movement while elevating said platform. Y .o i,

'7. In a truck of the class described,` a lifting head, an elevatingy platform, a hydraulicy lifting assembly, means pivoting said assemblylat its lower end to said lifting head, a ram extending substantially vertically from said assembly yand bearing at its .upper end against' said platform whereby to apply lifting effort to said platform and to control lowering movement of said vplatform, a pump included in said hydraulic lifting assembly, comprising fa plunger extending parw allel to said ram, a lever pivoted on said v lifting head and bearing against said pump plungerfor operating said Dump' plunger` in all positions thereof asithe Vhydraulic assembly moves on its pivot while the platform is being elevated, means for moving said lever to operate the` plunger, and

means mounting said platform for elevating movement relatively to said lifting head in substantially'a predetermined line whereby the hydraulic lifting assembly extending between said head and platformreceives but slight pivotal movement while elevating said platform.

8. In a truckof the class described, a'lifting head, an elevating platform pivoted to said lifting head, a hydraulic lifting assembly including a ram, 'means whereby said assembly is supported at its lower end on said lifting head for pivotal movement in a vertical plane longitudinal of the said truck, a thrust accepting means for said elevating platform against which the ram bears to lift the platform relatively to said lifting head. and means whereby said thrust accepting means are adapted for movement transversely relatively to said platform while imparting thrust thereto from said ram.

9. In a truck of the class described, a liftingV head, an elevating platform pivoted to said lifting head, a hydraulic lifting assembly including a. ram, bearing means whereby said assembly is supported at its lower end on said lifting head for free pivotal movement relatively to said lifting head, thrust accepting means carried by said elevating platform, a thrust member carried on means to lift the platform, the cooperation between said thrust member and said thrust accepting means'malntaining said hydraulic assembly particularly positioned on .said bearing means ,as

'said elevating .platformf moves vrelatively to said lifting head during the elevating movement thereof.

10.' In atlruck ofthe class described; a-Vliftlng head, an elevating platform pivoted to said lift- 4ing head, a hydrauliclifting assembly including a ram, means whereby said assembly is supported at its lower end on said lifting heady forlrpivotal movement ina vertical planelongitudinal of the said truck, ahthrust accepting assembly for said platform including a transverse beam against the centralportlonrof which the nam bears,` and a roller ateachend of said beam bearing against a surface of said platform, whereby said platform may move transversely relatively :to said-beam on said rollers while .accepting thrusttherefrom through said rollers. f

l1l. In a4 truck of theclass-described a lifting head, an elevating platformpivoted to said lifting head, a hydraulic lifting assembly including .a

accepting thrustv therefrom through said rollers.

12Inatruck of thevclass described, a lifting head, en -elevating. platform pivoted to saidlifting head, a hydraulic lifting assembly including a ram, means whereby said assembly is supported atits lower end on said liftinghead for. pivotal movement in la verticalrplaney longitudinal of the said truck, a thrust accepting assembly for.

said platform including a transverse beamagainst the central portion of which the ram isadapted to kbeanaa roller, at each end of said-beam bearing againsta cooperatingsurface-of said platvfcrmgwhereby said platform may movetransversely. relatively to said beam on said rollers vwhile..accepting thrust therefrom through said rollers,v and means between said ram and vsaid beamin rotatable thrust engagement wherebyto permit rotation of said beam relatively to said ram.k

, 13.- In a ytruclr of the class described, an elevating platform, lift .thrust imparting means, a

lift thrust accepting assembly for said platform includinga ,transverse beam, ,a roller at each endofsaid beam, and a surface on said platform resting on said rollers whereby said platform is movable relatively to said beam on said rollers.

means formed on said casting and whereby it is pivotallv secured to said lifting head, a sleevelike cylinder threaded in to said base casting, a

reservoir chamber formed insaid base casting and extending about the lower portion of said cylinder, a. cover plate for said reservoir having an opening through which the upper portion of said cylinder extends, .a ram in said cylinder bearing at its upper end and against said plat--v form whereby to impart lifting movement to said platform, and pump means in said assembly for applying fluid under pressure to said cylinder whereby to impart movement to said ram 15. In a truck of the class described, a lifting head, a steering head rotatable relatively to the front end of said head and carrying wheelsfor supporting said lifting head, a vertically extending standard forming the rear of said lifting head, a load platform having a vertically extending standard. `a link pivoted at its front end to the upper end of said lifting head standard and pivoted at its rear end near the upper end of said platform standard, a transverse shaft supported on the lower end of said lifting head standard, a link pivoted at its front end on said shaft and pivoted rearwardly thereof at substantially the' lower end of said platform standard, a hydraulic lift assembly comprising a base carrying theusual reservoir, ram and pump, bearing means on said base whereby it is pivotally supported on said transverse shaft and with the upper end of the ram of said assembly bearing againstV the said vertical platform standard, a pump actuating lever pivoted on the vertical standard of said lifting head, and vertically swinging means connected to said lever for moving it to operate said Dump.

16. In a truck of the class described, a lifting head, a steering head rotatable relatively toA the front end of said head and carrying wheels for supporting said lifting head, a vertically extending standard forming the rear of said lifting head, a load platform having a vertically extending standard, a link pivoted at its frontend to the upper end of said lifting head standard and pivoted at its rear end near the upper end of said platform standard, a transverse shaft supported on the lower end of said lifting head standard, a link pivoted at its front end' on said shaftand pivoted rearwardly thereof at substantially the lower end of said platform standard, a hydraulic lift assembly comprising a base carrying the usual reservoir, ram and pump, bearing means on said base whereby it is pivotally supported on said transverse shaft and with the uppernend of the ram of said assembly bearing against the said vertical platform standard,'a pump actuating lever pivoted on the vertical standard of said lifting head, and a vertically swinging pedal pivoted on said transverse shaft and connected to said lever for moving it to operate said pump;

17. In a truck of the class described, a lifting head having a vertical standard, a steering head supporting said lifting head, a steering handle mounted on said steering head for vertical swinging movement, an elevating platform having a standard and pivotally connected through upper and lower links to said lifting head standard, a hydraulic lift unit pivoted at its lower end to said lifting head and extending vertically between said standards, a ram forming part of said lift unit and bearing with its upper end against the standard of said elevating platform whereby to lift said platform on said upper andiower links relatively to said lifting head, a pump plunger forming part of said hydraulic lift unit, a lever pivoted on said lifting head standard and having one end bearing directly against said pump plunger in all positions thereof, for operating said pump in all positions `of said lift unit as said elevating platform is lifted, and a vertical strut for connecting the other end of said lever tov said steering handle whereby vertical swinging of said handle actuates said pump plunger.

18. In a truck of the class described, a lifting head'having a vertical standard, a steering head supporting said lifting head, a steering handle mounted on said steering head for vertical swinging movement, an elevating platform having a standard and pivotally connected through upper and-lower links to said lifting head standard, a hydraulic lift unit pivoted at its lower end to said lifting head and extendingV vertically between said standards, a ram forming part 'of said lift unit and bearing with its upper end against the standardv of said elevating platform whereby to lift said platform on said upper and lower links relatively to said lifting head, a pump plunger forming part of said hydraulic lift unit, a lever pivoted on said lifting head standard and having one end bearing directly against said pump plunger in all positions thereof for operating said pump in all positions of said lift unit as said elevating platform is lifted, and means connecting the said lever to said steering handle whereby vertical swinging of said handle actuates said pump plunger.

19. In a truck of the class described, a lifting head having a vertical standard, an elevating platform having a, standard and pivotally connected` through upper and lower links to said lifting head standard, a hydraulic lift'unit pivoted at its lower end to said lifting head and extending vertically between said standards, a ram forming part of said lift unit and bearing with its upper end against the standard of said elevating platform whereby to lift' said platform on said upper and lower linksrelatively to said lifting head, a pump plunger forming part of said hydraulic lift unit, a'lever pivoted on said lifting head standard and having one end bearing directly against said pump plunger in all positions thereof for operating said pump in ll positions of said lift unit' as said elevating platform is lifted, and means connected to the said lever for moving it to actuate said pump'plunger.

- GEORGE QUAYIE.

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