US2672249A

US2672249A - Truck-mounted load pusher and puller

Info

Publication number: US2672249A
Application number: US71500A
Authority: US
Inventors: Bronislaus I Ulinski
Original assignee: Yale and Towne Manufacturing Co
Current assignee: Yale and Towne Manufacturing Co
Priority date: 1949-01-18
Filing date: 1949-01-18
Publication date: 1954-03-16
Anticipated expiration: 1971-03-16

Description

March 16, 1954 B. ULINSKI 2,672,249

TRUCK-MOUNTED LOAD PUSHER AND FULLER Filed Jan. 18, 1949 5 Sheets-Sheet l :Inl I fa/hwlz ATTORNEY March 16, 1954 B. l. ULINSKI 2,672,249

TRUCK-MOUNTED LOAD PUSHER AND FULLER Filed Jan. 18, 1949 5 Sheets-Sheet 2 om F m g? g @512 N INVENTOR ATTORNEY March 16, 1954 B. l. ULINSK! 2,672,249

' TRUCK-MOUNTED LOAD PUSHER AND FULLER Filed Jan. 18, 1949 5 Sheets-Sheet 5 ulllllmlllh EHIIETWIH lHIlIIBlHW Lulmmum' MHIHM 54 H, 34

II III] 11 Hlll INVENTOR ATTORNEY March 16, 1954 B. 1. ULlNSKl 2,672,249

TRUCK-MOUNTED LOAD PUSHER AND FULLER Filed Jan. 18, 1949 5 Sheets-Sheet 4 INVENTOR 6, l c/mw/ WrG/M.

ATTO R N EY March 16, 1954 B. I. ULINSKI TRUCK-MOUNTED LOAD PUSHER AND FULLER 5 Sheets-Sheet 5 Filed Jan. 18, 1949 midi MMEQEQ VGMIU Imam n56 32 nll INVENTOR ,6 I c /w f/ BY ATTORNEY Patented Mar. 16, 1954 UNITED STATES TENT OFFICE TRUCK-MOUNTED LOAD PUSHER AND FULLER Application January 18, 1949, Serial No. 71,500

17 Claims. 1

This invention relates to an attachment preferably adapted to be applied to an industrial lift truck, but adapted also to be embodied as an integral part thereof. More particularly, my in vention relates to an attachment for a lift truck adapted to push a load linearly 01? the load platform of a truck of the particular class. A further portion of my invention relates to means adapted to pull a load onto the platform of the truck, so that in effect, my invention may be utilized for both pushing and pulling a load or for pushing only.

As a feature of my invention, my attachment is readily applied to any usual type of truck. As a further feature, when so applied, the attachment may be readily connected for immediate operation.

Load pushers and pullers are old and well known in the art. However, they are generally quite bulky, inefilcient and expensive, and have not therefore been generally accepted for material handling. As a particular feature of my invention whereby it is rendered desirable and effective, my attachment is arranged to occupy an exceedingly small space so as not to increase the overall length of the truck. In addition, the attachment is so formed that it is considerably narrower than any usual standard type of load platform so as not to increase the overall width of the truck.

A further feature of my invention resides in the extremely novel concept of means carried by the attachment and connected respectively to what I term a load actuator and a part of the truck, for operation by a ram assembly to move the load actuator to and from the main frame of the truck. A particular feature of this part of the invention resides in an extremely efficient arrangement of movement multiplying means whereby a relatively short throw achieved by the ram assembly will effect a long throw of the load actuator and considerable linear movement of the load moved by the actuator.

A still further feature of my invention resides in the utilization of a load gripping assembly that may readily be applied to the load actuator of my invention so that the load actuator may become a load puller as well as a load pusher. As a particular feature of this part of the invention, the load gripper is adapted for movement to grip the load prior to movement of the actuator so that no special means must be manipulated by an operator to grip a load and then move it linearly. As a still further feature of this particular part of my invention, the load gripping means release the load at all times upon the stopping of the load moving operation.

invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which my disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of my invention. It is important, therefore, that the claims to be granted me shall be of sufiicient breadth to prevent the appropriation of my invention by those skilled in the art.

Referring now to the drawings, Fig. 1 is a view of one end of an industrial truck showing my invention applied thereto and forming a part thereof. Fig. 2 is an end elevation of the truck of Fig. 1. Fig. 3 is an exploded view of certain of the parts of the ram assembly of my invention. Fig. 4 is a view of the parts of the ram assembly after some movement of certain of the parts thereof from the position of Fig. 1. Fig. 5 is a section taken along lines 55' of Fig. 4. Fig. 6 is a section taken along lines 66 of Fig. 5. Fig. '7 is a view looking downwardly on the ram assembly and the parts actuated thereby when the load actuator has been fully extended relatively to the truck frame. Fig. 8 is an elevation showing the construction of the load actuator. Figs. 9 and 10 are sections taken along lines 9-43 of Fig. 8 showing the gripper mechanism in two positions. Fig. 11 is a section through the gripper operating hydraulic means. Fig. 12 is a schematic drawing of the hydraulic mechanism of my invention.

Referring now more particularly to the drawings, and more especially to Figs. 1 and '7, I show at ill the primary uprights of a standard type of industrial truck, the secondary uprights being designated by reference numeral II. The load wheels of the truck are shown at [2, and at 13 there is shown a load carriage mounted through upper and lower rollers I l for vertical movement on the secondary uprights H. The attachment of my invention is here shown as applied to the carriage 13. Of course, those skilled in the art will understand that my attachment may be applied to any part of the main frame of an industrial truck and that it is herein shown as applied to the main frame carriage l3 because that is the preferred manner in which my invention will probably be used at the present time. It should further be understood that while I call my invention an at tachment, it can actually be an integral part of the truck. Thus, the base member of my attachment is designated by reference numeral l5 as best seen in Fig. 4 and this basemember may be welded to part of the main frame of a truck or may be applied to. the main. frame carriage l3 by merely forming on the base member IS a lip i6 adapted to coact with the end plate [3a of the carriage 13. The attachment thus is secured for movement with the carriage as a part thereof.

What I have heretofore termed the ram assembly of. my invention, I designate by, reference numeral 17, the said ram assembly being well illustrated in Figs. 1, 2, 4, 5, and '7. Ram assembly ll may be formed of one or more castings, the upper casting being shown supporting thereon what I term a ram cylinder l8. Cylinder 18 has a shaft portion llheld by a heavy nut idea in fixedrelation to the upper casting of ram assembly H as best seen in Fig. 5. A ram piston 231s mounted for vertical movement relatively to the ram cylinder l8 and is threaded at 2| so as to be secured to a heavy lower casting 22 of the ram assembly best illustrated in perspective in Fig. 3. Casting 22 has secured thereto through suitable nuts23 a pair of racks 24, each of which is formed with teeth on its forward and rear faces. Each rack 24 cooperates with four gear sectors, there being two

upper gear sectors

25, 26 and two

lower gear sectors

27 and 28 in engagement with the rack teeth.

The gear sectors. are all similar in construction, and each gear sector is secured to a lever. Thus, gear sector 25 is secured to a lever 29, while

gear sectors

26, 21, and 28 are secured respectively to levers 30, 3|, and 32. Considering first lever 29, we find that it is bored at 33 for a bearing shaft 34 carried by the upper casting of the ram assembly I? throughthe intermediary of a bearing sleeve 35. Between the lever 2i; and the ram assembly ll there is positioned the gear sector 25, this gear sector being bored at 36 for the bearing shaft 3 3. Gear sector 25 is further bored at 31 for a bolt 38, this bolt passing through a bore 39 in the lever 29, Bolt 38 is headed at one end to lie in a counter-bored portion of bore 31 and is threaded at its other end for a nut ll). It is obvious that the nut 49 and the bolt 38 thus secure the gear segment 25 to the lever 29 for integral rotation therewith on the bearing shaft l4, and relatively to the ram assembly [1.

All the remaining levers and gear segments are similarly secured to the ram assembly I'l, except that the lower levers 3i, 32'a1'e in offset relation to the

levers

29 and 39, even though the gear sectors 2T, 28 are in substantial alignment with the

upper gear sectors

25, 26. Thus, as is best seen in Fig. 5, lower lever 3i lies at the right of its particular gear sector 21 for rotation therewith relatively to the ram assembly ll. Because the lower lever 31 is so offset relatively to upper. lever29, the two levers can lie in substantial verticalialignment as shown in Fig. 1. At the same time, of course, upper lever 39 can lie in substantial vertical alignment with lower lever 32.. It will be well at this point to indicate further that the mounting of the four levers 29-32 that I have thus described is duplicated at the right side of the ram assembly pictured in Fig. 5, there being thus eight levers, with four mounted at each side of the ram assembly.

Upper lever 38, as best seen in Figs. 4 and 7, is pivoted-througha shaft 4t relatively to-a bracket portion 52 forming part, of. the base member l5 of my invention. Lower lever 32 is pivoted through a shaft 43 to the same bracket 22 of the base member 15. Because of the particular arrangement, the offset relationship of the levers 3i332 previously stressed is useful also in more rigidlymounting the levers 3El-32 relatively to the mainframe l5. Of course, the levers at the opposite side of. the ram assembly i! will be similarly pivoted to a bracket 42a as need not here be emphasized.

Levers

29 and 3| at the right side of the ram assembly pictured in Fig. 4 are pivoted to

brackets

55, 45a forming integral parts of whatI term an actuator A. This actuator, A may be fabrie cated in any desiredmanner, one particular form of fabricationbeing that illustrated best in, my drawings andespecially in Figs. 7, 8 and9. Naturally, the

levers

29 and 3! will form a fairly rigid connection between the ram assembly I! and theactuator because of the particular olfset relation that has already beenreferred to, It is now quite obvious that when the ram piston 2G is moved relatively to the ram cylinder 18 from its full line position of Fig. 1 to the full line position of Fig. 4 and then to its dash and dotted line position of Fig. 1, the racks 24 willeffect movement of theeight levers comprising levers 29-32. These levers will move from the full line position of 'Fig. 1 to the dash and dottedline. position of Fig. 1 and theposition illustrated in Fig. '7. Because of the parallelogram relationship between the several levers and the main frame of the truck on the one side and the load actuator A on the other side, theload actuator will beextended a considerable distance away from the main frame of the truck. Upon opposed movement of the ram piston 20', the actuator will, of course, be brought into very close coupled relation to the truck.

As is quite apparent from Figs. land 2, when the load actuator. is brought closely to the main frame of'the truck, my entire assembly including the load actuator occupies but very little space. Therefore, the overall length of the truck is not substantially increased. Similarly, as is particularly well seen in Fig. 2, the width of my attachment is considerably less than the width.

of the truck so that my attachment does not increas the overall width of the, truck as isthe case in many prior art constructions.

The load actuator A has formed thereon a gripper plate (is extending for thefull widthof the actuator.. This gripper, plate is. preferably made quite rigid and is .weldedtothe brackets 45, 45a. and the actuator. In addition, the plate 45 is so formed that its lower surface 46a will lie in juxtaposed relation to theupper surface ll of a pair of forks 48 extending fromand forming a part of thecarriage 53.0f myinventiom 0f course, the forks t8 vcouldconceivably-be secured to the base member I5. of myattachment, but I prefer to applythe forks directly toplate |3a just as member 55 is. applied to plate 130... In either case, itis importantmerely tolznow that I do prefer to use forks one platform cooperating with the load-actuator. A, and that these forks or the platform may be apart of the truck or. part-of my. attachment, theoperation being the same regardlessof the particular relationship of the parts. It is now apparent, however, that during the linear movement of the actuator from the full line position of Fig. l to the dash and dotted line position of Fig. 1, the gripper plate 46 will lie in uxtaposed relation to the upper surfaces It? of the forks 43.

Extending from the actuator A is a pair of upper brackets 39, there being pivoted to each bracket $93 at iii), a ram cylinder 5! of what I term a gripper ram. Within each ram cylinder 5| there is mounted a ram piston 52 equipped with a piston head 53. A spring presses at one end against each piston head 53 and at its other end against a washer 55 carried by a closing block 56 that closes the lower end of each ram cylinder 59. The lower ends of the two ram pistons 52 are secured to a gripper bar 5? adapted to coact with the gripper plate 36. Gripper bar 5? has at its lower end a rubber part 58 adapted to ride toward a groove 59 in the gripper plate 6 so as to grip a paper or thin metal plate til as well illustrated in Figs. 9 and 10. Gripper bar 5? has a series of brackets 6! whereby to be pivoted to a series of levers 62 that are in turn pivoted at 63 to the main frame of the actuator A. In this manner, the movement of the gripper bar 5i is controlled between an upper position of the gripper bar illustrated in Fig. 9, and a lower gripping position illustrated in Fig. 10. It will be further appreciated that the gripper bar ill will move from the position of Fig. 9 to the position of Fig. upon movement of the pistons 52 by the introduction of hydraulic fluid into the ram cylinders 5!. It will be further understood that this movement will be in opposition to the two springs 54 of the two rams and that when the application of fluid to the piston heads 53 stops, the springs 5 1 would immediately act to return the gripper bar to the position of Fig. 9.

It will be recalled that in Fig. 5 the shaft 34 was described as mounted within a bearing sleeve 35 carried by the ram assembly ll. As a very important feature of my invention, I make it possible to adjust each of the shafts 34 relatively to the ram assembly H, and thus am able to compensate for any errors in the fabrication of my assembly, the several levers, and all the other operating parts thereof that I have described. I am able to obtain this adjustment of the shafts 34 by forming each of the sleeves 35 so that its i bearing relatively to the assembly H is eccentric with regard to the axis of the shaft 35. The particular sleeve 35 to which I have alluded is shown in Fig. 6, and as there seen is formed with a flange 64 that is castellated as at 65 for coaction with a wrench. A locking lug 66 held by a screw 61 is adapted to coact with the castellations 65 to hold the flange 6 1 and the bearing sleeve 35 in any position to which it may be rotated by a wrench applied thereto. It is therefore seen that merely by removing the locking lug 3b, the sleeve 35 may be rotated into a particular adjusted position and then looked in that position. As will be seen in Fig. 5, each of the four bearing sleeves there illustrated is formed in exactly the same manner as the bearing sleeve just described, and is similarly held locked in any adjusted position to which it may be moved.

Referring now to Fig. 12, I show a schematic view of the several parts of my invention whereby the push pull ram assembly and the gripper rams are operated. It will be noted that I employ a reservoir 68 in communication with a gear pump 69 that is driven by a motor ltl. Preferably all these parts are carried by base member 55 of my attachment so that the entire attachment may readily be applied as an operating unit to a truck. The pump 69 moves fluid from the reservoir past the check valve H and through pipe 13 to a selector valve having a rotating valve body 19 equipped with passages 80, 8 l. The selector valve has for communication with the passages 80, 8|,

passages

82, 83, B4, and 85. Passage 83 communicates with a pipe 86 that leads to the upper end of the push-pull ram cylinder l8 as is not only shown in Fig. 12, but may also be seen in Fig. 5. Passage 84 leads to a pipe 8? that is in communication with the reservoir. Passage 85 leads to a pipe 88 that connects with a pipe 89 leading to the upper ends of the two gripper ram cylinders 5!. Pipe 88 continues also into a sequence valve where it is in communication with a passage 98 and a passage 9!. Passage 9! is in communication past ball valve e2 with a passage 93 leading to pipe 94. Pipe 9 goes to the lower end of the push-pull ram cylinder 58. Passage 90 leads past a valve to a passage 93 in communication with pipe 94 and the lower end of the push pull ram cylinder I8.

In the position of the parts shown in Fig. 12, the selector valve has been actuated so that its rotating body 79 is in a pull-grip position calling for a gripping of the load and a pulling of the load actuator A from its dash and dotted line position of Fig. 1 to its full line position of the same figure. Let us now consider just how the fluid flows. First, the gear pump will be actuated by the closing of the motor circuit to bring fluid from the reservoir past the check valve H and into pipe '58. The fluid will then flow through passage 82, passage 83, passage t5, and pipe 83 toward the sequence valve. The fluid cannot, of course, flow past the ball valve 92, but it will flow towards the valve 95. The setting of the valve 95 is such that considerable pressure will be required to unseat the valve. Therefore, the fluid will first flow through pipe 89 toward the two gripper ram cylinders 5!. The pistons 52 of the gripper rams will be actuated and will move downwardly against the force exerted by springs 5G, thereby bringing the gripper bar 5? downwardly to its position of Fig. 10 so as to grip a paper 60 on which a load may have been placed. As soon as the gripper rams have thus been actuated, pressure will build up in the system until the valve Q5 of the sequence valve body will be unseated. Fluid will now flow through passages 9t, 96 into pipe 95 to the lower end of the push pull ram cylinder I 8. The ram is will now move upwardly from its dash and dotted line position of Fig. 1 to its position of Fig. i, and then will continue to its solid line position of Fig. 1. The fluid on the upper side of the ram piston 20 will move through pipe 86 and thence through passages 83, 8!, 34 to pipe 8'? and back to the reservoir 68.

When the uppermost position of the push-pull ram piston 20 is reached, the selector valve body 79 will be rotated to a hold position. This stops the motor and brings passage 30 into communication with

passages

84, 85. At the same time, passage 8| will be brought into communication with

passages

82 and 83. With the parts in this position, fluid will no longer flow toward the push-pull ram. However, the push-pull ram will not move downwardly because no fluid can flow from its lower end because of the seating of the ball valve 52 in a particular position. Fluid cannot move from the other side of the push-pull ram because of the presence of check valve H and gear pump 69. Therefore, the actuator will reaer acac main' in the particular positionto which it has been moved, and this is a particular feature of my inventionthat I believe to be of considerable importance At the same time, however, fluid will flowfrom above the gripper rams as the gripper rams -are moved upwardly by springs 54..

Thus, the fluid will flow through pipe 89, pipe 88, passage 85, passage 80, passage 84, pipe 81, and to reservoir 68. Because of this arrangement, it is apparent that immediately upon the stoppage of the pulling movement of the load actuator, the gripper-bar 5! will release the paper or'other type.

sheeton which a load has been placed.

Let us now consider that in the full line position of the parts in'Fig. 1 a load rests on the forks "and on the upper surface of the said forks and that it isdesired to push the load-off the forks.

Selector valve is now rotated to push position to bring passage 80 in communication with

passages

82, 83 and passage 8| in communication with

passages

84, 85, while the motor I is simultaneously started; Fluid will now flow from the reservoir 88 through gear pump 69 past check valve H into pipe 18. From the pipe '58 fluid will flow through passage 82, passage 80 and to passage -83 to pipe 85. and the upper end of the ram cylinder It. This will effect a downward movement ofthe ram pistonZll from its full line position of Fig. 1 to its dash and dotted line position of Fig. 1. This movement of the ram piston 20 will, of course, effect movement of the actuator from its solid line position of Fig. l to its dash and dotted line position of the same figures and the load .will be moved off the forks 48. At the same time, fluid will flow from below the ram piston 28 through pipe 94 with the pressure sufficient to unseat ball valve 92. Fluid will continue to flow through pipe 88 into passage 85 and thence through passages 84, 8|, 85 into pipe 8'! and back to the reservoir. It will be noted that no fluid will flow to the gripper ram cylinders Therefore, when the selector valve is operated in this last manner, the push-pull ram alone will be operated and the load will be moved, but there will be no actuation of the gripper bar 51. It will be well to emphasize that the controls thus described are purely schematic and that many arrangements of valves and other means can readily be conceived for yieldingthetype of control I have contributed here.

I believe that the operation of my invention as Y ram assembly, a load actuator, a ram piston in said ram' assembly movable relativelythereto,

upper and lower levers pivoted at one end thereofto onesideof said ram assembly, the other ends of said levers being'pivoted to said frame so as to form a parallelogram arrangement of said levers and said f-rame and ram assembly, upper and lower levers similarly extending between the other side of said ram assembly and said load actuator and. similarly secured thereto, and means whereby said ram piston applies force directly to each of the four ends of said four levers pivoted to saidram assembly for swingingsaid four levers on their pivots to move said load actuator toward and away fromsaidframe.

2. In a truck of the class described, aframe, a load actuator, a ram assembly positioned in spaoedrelation tosaid frame andload actuator, a ram piston in said ram assembly movable relatively thereto, upper and lower levers pivoted at one end thereof to one side ofasaid ram assembly, the other ends of said levers-being pivoted to said frame so'as to form a parallelogram arrange ment of said levers and said frame and ram assembly, upper and lower levers similarly extending between the other side of said ram assembly and said load actuator and similarly secured thereto, rack means movable by said ram piston, and gear means whereby said rack means moves directly each ofsaid four levers on their pivots to movesaid-loadactuator toward and away from saidframe.

3. In atruck of the class described, a frame, a ram assembly, a load actuator, a ram pistonin said ram assembly movable relatively thereto,

upperlandlower levers pivoted at one end thereof to oneside of said ram assembly, the other ends.

of said levers being pivoted tosaid frame so as to form a parallelogram arrangement of said levers and said frame and ramassembly, upper and lower levers similarly extending between'the other side of said ram assembly. and said'loa'cl actuator and similarly secured thereto, a gear sector secured to each of saidfour levers, andatwo-faced rack positioned between the gear. sectors of the levers for actuating all four ofsaid levers simultaneously to move said load actuator toward and away from said frame.

4. In a truck of the class described, a frame, a

ram assembly, a load actuator, a ram piston in said ram assembly movable relatively thereto,

upper and lower levers pivoted at one end thereof. to one side of said ram assembly, the other ends said levers being pivoted to said frame so as toform a parallelogram arrangement of said levers and said frame and. ram assembly, upper and lower levers similarly extending betweenthe other side of said ram assembly and said loadv actuator and similarly secured thereto, gear;.sectors secured to each of said four levers coaxially with the pivots of said lever to said ram assembly, anda two-faced rack positioned between thefour gear sectors of the levers for actuating all four 'of said levers simultaneously to. move said loadv actuator toward and away from said frame.

5. In a truck of the class described, a framaa ram assembly, a load actuator, a ram piston in:

said ram. assembly movable relatively thereto,

upper and lower levers'pivoted at one end thereof to'one side of said ramassembly, the other ends of said levers being pivoted to said frame so as to form a parallelogram arrangementof said levers; and said frame and ram assembly, upper and.

said levers move into coincidence to bringsaid' ,load actuator and main frame into the closest.

possible relationship.

6. In a truck of the class described, a frame, a ram assembly, a load actuator, a ram pistonin said ram assembly movable relatively thereto, upper and lower levers pivoted at one end thereof to one side of said ram assembly; the other ends of said levers being pivoted to said frame so as to form a parallelogram arrangement of said levers and said frame and ram assembly; up-

. per and lower levers similarlyextending betweenthe other side of said ram assembly and said load actuator and similarly secured thereto, and means whereby said ram piston applies force directly to each of the four ends of said four levers pivoted to said ram assembly for swinging said four levers on their pivots to move said load actuator toward and away from said frame, said upper and lower levers at each side being laterally ofiset relatively to one another so that the longitudinal axes of said levers move into coincidence to bring said load actuator and frame into the closest possible relationship.

7. In a truck of the class described, a frame, a ram assembly, a load actuator, a ram piston in said ram assembly movable relatively thereto, upper and lower levers pivoted at one end thereof to one side of said ram assembly, the other ends of said levers being pivoted to said frame so as to form a parallelogram arrangement of said levers and said frame and ram assembly, upper and lower levers similarly extending between the other side of said ram assembly and said load actuator and similarly secured thereto, means whereby said ram piston moves said levers on their pivots to move said load actuator toward and away from said frame, and eccentric sleeve bearings for at least certain of said pivots of said levers.

8. In a truck of the class described, a load actuator, a ram cylinder and a, ram piston for pushing and pulling said load actuator relatively to said truck, a source of fluid pressure, valve means set for holding said piston and cylinder against relative movement except upon application of fluid under pressure between said ram piston and ram cylinder from said source of fluid pressure, a gripper movably mounted on said load actuator, hydraulic means for moving said gripper relatively to a part of said actuator whereby to grip a part of the load between said gripper and said actuator, means whereb fluid under pressure is directed solely to one end of said ram cylinder to move said actuator to push a load, means whereby fluid under pressure is supplied to the other end of said ram cylinder to move said actuator to pull the load, means whereby fluid under pressure is first supplied to said hydraulic means in advance of said other end of said cylinder whereby the load is first gripped and then pulled, a spring pressing said gripper away from gripping position, and means releasing the fluid in said hydraulic means upon the stoppage of the flow of fluid under pressure to said hydraulic means whereby said spring moves said gripper to release the load whil said load actuator will be held in the position to which it was moved by the application of fluid under pressure to said piston and cylinder.

. In a truck of the class described, a load actuator, a ram cylinder and a rain piston for pushing and pulling said load actuator relatively to said truck, a source of fluid pressure, means for holding said piston and cylinder against relative movement except upon application of fluid under pressure between said ram piston and ram cylinder from said source of fluid pressure, a gripper movably mounted on said load actuator, hydraulic means for moving said gripper relatively to a part of said actuator whereby to grip a part of the lead between said gripper and said actuator, means whereby fluid under pressure is directed solely to one end of said ram cylinder to move said actuator to push a load, means whereby fluid under pressure is supplied to the other end of said ram cylinder to move said actuator to pull the load, means whereby fluid under pressure is first supplied to said hydraulic means in advance of said other end of said cylinder whereby the load is first gripped and then pulled, and a spring pressing said gripper away from gripping position whereby upon the stoppage of the flow of fluid under pressure to said hydraulic means said gripper will release the load while said load actuator will be held in the position to which it was moved by the application of fluid under pressure to said piston and cylinder.

10. In a truck of the class described, a load actuator, a ram cylinder and a ram piston for pushing and pulling said load actuator relatively to said truck, a source of fluid pressure, valve means set for holding said piston and cylinder against relative movement except upon application of fluid under pressure between said ram piston and ram cylinder from said source of fluid pressure, a gripper movably mounted on said load actuator, hydraulic means for moving said gripper relatively to a part of said actuator whereby to grip a part of the load between said gripper and said actuator, selector means whereb fluid under pressure is directed solely to one end of said ram cylinder to move said actuator to push a load upon the setting of said selector means in one position, the setting of said selector means in another position directing fluid under pressure from said source to said hydraulic means and also to the other end of said ram cylinder, and sequence means whereby said fluid under pressure first actuates said hydraulic means to grip the load and then actuates said ram and cylinder to pull the load.

11. In a truck of the class described, a load actuator, a ram cylinder and a ram piston for pushing and pulling said load actuator relatively to said truck, a source of fluid pressure, valve means set for holding said piston and cylinder against relative movement except upon application of fluid under pressure between said ram piston and ram cylinder from said source of fluid pressure, a gripper movably mounted on said load actuator, hydraulic mean for moving said gripper relatively to a part of said actuator whereby to grip a part of the load between said gripper and said actuator, selector means whereby fluid under pressure is directed solely to one end of said ram cylinder to move said actuator to push a load upon the setting of said selector means in one position, the setting of said selector means in another position directing fluid under pressure from said source to said hydraulic means and also to the other end of said ram cylinder, sequence means whereby said fluid under presure first actuates said hydraulic means to grip the load and then actuates said ram and cylinder to pull the load, and a spring pressing said gripper away from gripping position whereby upon the stoppage or" the flow of fluid under pressure to said hydraulic means said gripper will release the load while said load actuator will be held in the position to which it was moved by the application of fluid under pressure to said piston and cylinder.

12. In a truck of the class described, load supporting and raising means, load moving means carried by said load supporting and raising means, clamping means carried by said load moving means, hydraulic means for actuating said clamping means to clamp a part of a load, a ram for moving said load moving means relatively to the load supporting and raising means, a source of fluid pressure, a manually operated valve, means through which saidvalve when in one position directsfluidpressure toward said hydraulic means and said ram, and. a second valve automatically :directing the. fluid pressure first to said hydraulic means and then to said ram.

13. In a truck of the class described,:forward- 1y projecting load supporting and raisingmeans,

pusher means carried by said load supportingand raisingmeans, clamping means carried by said pusher means, hydraulic means for actuating said clamping means to clamp a .part of a load, a'ram for moving said pusher means forwardly and rearwardly relativelyto the load supporting and raising: means, asource offluid pressure, amanually operated valve, means through which said 1 valve when in one position-directs fluid pressure simultaneouslytoward said hydraulic means and said ram, and a second'valve automatically di- =recting the fluid pressure first to said hydraulic -means to effect-actuation of the clamping" means and then to saidram whereby toeifect rearward 'movement of the pusher-means and load subsequently to clamping of the load.

14. .In a truck of'theclass described, forwardly projecting load supporting and raising means,

vertical pusher meanscarried by said load supporting andraising means, clampingmeans car ried'by said-pusher means adjacent to the load supporting surface of said load supporting means,

hydraulic means for actuating said clamping 'means to clamp'a part of a load, a ram for moving said pusher means forwardly and rearwardly relatively to the load supporting and raising means, a source of fluid pressure, a first valve, means through which said valve when in one position directs fluid pressure simultaneously toward said hydraulic means and said ram, said hydraulic means being in direct unobstructed communication with said first valve, a further valve interposedbetween said ram and said first valve for preventing theflow of fluid to said ram, and

means forming a part of said further valve and porting and raising means, clamping means carried by said pusher means adjacent to the load supporting surface of said load supporting means,

"hydraulic means for actuating said clamping means to clamp a part of a load, a ram for moving-said pusher means forwardly and rearwardly relatively to the load supporting and raising means, asource of fluid'pressure, a manually operated valve, means "through which said valve when in one position directs fluid pressure toward said hydraulic means and said ram, a second valve automatically effecting the flow of fluid first 'tosaid hydraulic means until development of predetermined fluid pressure incidental to actuationtof the clamping means, and then to one end -of:said ram, whereby to effect clamping of the load and rearward movement of the pusher means and load, and means through which said manually operated valve-when in a second position directs fluid pressure 'to the opposed end of said ramito move the pusher means'forwardly relativelyto-the load supporting and raising means while simultaneously effecting the exhaust of fluid from said hydraulic means.

16. Ina truck of the class described, forwardly projecting load supporting and raising means,

pusher means carried by said *loadsupportin'g (ill .and raising means, clampinglmeans carried by said pusher means, hydraulic means for actuating said clamping means to:clamp a part of aload,

,a;ram for moving said pusher means forwardly and rearwardly relatively to the loadsupporting and raising means, a:source of fluid pressure, a manually operated valve, means through'which said valve-when in one-position directs fluidpressure simultaneously toward said. hydraulic means and said ram,;a second valve automatically effecting the flow of fluid first to said hydraulic means to effect actuation of the clamping-means, andthenztoone end of. said ram whereby to effect .rearward movement of the pusher means and load, and'means through which. said manually operated valve when in a second position directs fluid pressure to the opposed end of said ram'to move thepusher means forwardly relatively to the load supporting and raising means while simultaneously effecting the exhaust of fluid from said. hydraulic means.

17. Ina truck of .the'class described, load'sup- .porting and raising means, pusher means carried by said load supporting and raising means, clamping means carried ,by said pusher means, hy-

draulic means for actuating said clamping means to clamp a part of a load, a ram for movingv said pusher means forwardly and rearwardly relatively to the loadsupporting and raising means, a source of fluid pressure, a first valve, means through which said valve when. in one. position directs fluid pressure toward 'said hydraulic means and simultaneously toward one end of said ram, a second valve automatically effecting the flow of fluid first to said hydraulic means to clamp the load, and then to the said end of the ram upon development of predetermined fluid pressure incidental to actuation of the clamping means whereby to move the pusher means and load rearwardly, means through which said first valve when in a second position directs fluid pressure to'the opposed end of said mm to move said pusher means forwardly, springs pressing said clamping means toward release position, and said first valve in its second position effecting the exhaust of fluid from said hydraulic means under the pressure of the springs on said clamping means.

BRONISLAUS I. ULINSKI.

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