US3183989A

US3183989A - Hand lift truck

Info

Publication number: US3183989A
Application number: US180124A
Authority: US
Inventors: George J Trusock; Kenneth C Johnson
Original assignee: Individual
Current assignee: Doosan Bobcat North America Inc
Priority date: 1962-03-26
Filing date: 1962-03-26
Publication date: 1965-05-18
Anticipated expiration: 1982-05-18
Also published as: GB978969A; GB978970A

Description

G. J. TRUSOCK ETAL May 18, 1965 HAND LIFT TRUCK Filed March 16. 1962 4 Sheets-Sheet l INVENTORS GEORGE J. TRUSOCK BY KENNETH C. JOHNSON ATTORNEY G. J. TRUSOCK ETAL 3,183,989

May 18, 1965 HAND LIFT TRUCK 4 Sheets-Sheet 2 Filed March 16, 1962 INVENTORS GEORGE .1. TRUSOCK KENNETH c. JOHNSON ATTOR NEY y 18, 1965 G. J. TRUSOCK ETAL 3,183,989

HAND LIFT TRUCK F iled March 16, 1962 r 4 Sheets-Sheet 3 FIG. 3

2 9 82 IN VENTORS GEORGE J TRUSOCK KENNETH C. JOHNSON ATTORNEY y 1965 G. J. TRUSOCK ETAL 3,183,989

HAND LIFT TRUCK 4 Sheets-Sheet 4 Filed March 16, 1962 INVENTORS GEORGE J. TRUSOCK KENNETH C. JOHNSON ATTORNEY viewed in FIGS. 1 and 2;

United States Patent 3,183,989 HAND LIFT TRUCK George J. Trusock, Battle Creek, and Kenneth C. Johnson,

Kalamazoo, Mich, assignors to Clark Equipment Company, a corporation of Michigan Filed Mar. 16, 1962, Ser. No. 180,124 9 Claims. (Cl. 180-13) Our invention relates generally to power operated hand lift trucks, and more specifically to the construction of the frame and lifting means therefor.

Presently, powered hand lift trucks commonly comprise the primary elements of a main frame which is supported by a drive head and wheel unit rotatably mounted therein about a vertical axis, and a load supporting frame disposed forwardly of the main frame and supported at its forward end by means of extensible wheels. The load supporting frame is mounted for vertical movement on the main frame by means of vertical slides and roller members. Vertical movement of the load supporting frame is commonly effected by means of a pair of transversely spaced hydraulic piston and cylinder assemblies connected by suitable linkage means to the extensible wheel assemblies for extending and retracting the latter to elevate and lower the load supporting frame which, as mentioned above, is guided on the main frame by means of the vertical slides and roller members.

It is a primary object of our present invention to provide in a hand lift truck of an improved construction of the load supporting means and of the means for elevating the load supporting means.

. It is another object of our invention to provide in a hand lift truck improved means for facilitating lateral adjustment of the pallet legs thereof.

Another object of the invention is to provide a simplified, less costly and more efficient hand truck construction 'than heretofore, while maintaining a short length of the ing forwardly extending linkage members which are connected to lever supported trail wheels adjacent the front end of the load supporting frame for raising the front end thereof with the rear end upon actuation by the hydraulic motor. The lift linkage means are located transversely outwardly of portions of the horizontal legs I of the load supporting frame such that the pallet arms extending forwardly of said frame can be adjusted laterally within limits without requiring any change in basic truck structure.

Other objects, features and advantages of the invention will become apparent to persons skilled in the art in view of the description below of one embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a side View of a hand lift truck which embodies our invention;

FIGURE 2 is a plan view of FIG. 1 showing certain portions broken away;

FIGURE 3 is an enlarged partially broken-away view of the truck taken from the right-hand end thereof as FIGURE 4 is a broken-away side elevational view of the truck showing the load supporting frame in an elevated position;

FIGURE 5 is a reduced perspective view showing the load supporting frame per se; and

FIGURE 6 is an enlarged plan view of the tip portion of one of the pallet legs showing the manner of mounting the trail wheel assembly.

Referring now in detail to the drawing, there is indicated generally by the reference numeral 10 a hand lift truck which comprises a reversed generally L-shaped main frame 12, a forwardly extending L-shaped load supporting frame 14 having the vertical leg means thereof mounted in telescoping relation to the vertical leg means.

of main frame 12, said

frames

12 and 14 including

transverse frame members

17 and 18, respectively, having mounted centrally therebetween and extending vertically thereof a single, relatively short hydraulic cylinder-piston motor 20 for lifting frame 14 relative to frame 12.

Rotatably mounted about a vertical axis in the main frame 12 is a drive head unit indicated generally by numeral 16 which is supported on a ground engaging drive-steer wheel 19. Wheel 19 is powered by an electric motor enclosed in the drive head unit and adapted to have driving connection with the drive wheel through suitable gearing, and to have electrical connection with the battery carried by the truck in battery compartment 22. The truck may include a motor driven pump uni-t 24 having a suitable electrical and hydraulic connections for operating hydraulic devices on the truck, such as piston and cylinder assembly 20 by way of

conduits

26 and 28.

The upper end of drive head unit 16 is secured in the inner race of a tapered roller bearing assembly 30, the outer race of which is secured in a horizontal plate member 32 suitably connected to the main frame 12. The lower end of the drive head unit 16 is supported and guided in a circular ring or track member 34 which is secured to the main frame. Four spaced rollers 36 are connected to the drive head unit and engage track 34 such that the drive unit 16 and drive wheel 19 may be steered in either direction by a steering and driving operators control handle assembly 48 which is pivoted to the drive unit 16 by a pin 42, and which is also adapted to control the application of and release of brakes, not shown, associated with drive unit 16. The construction and mounting of drive unit and

wheels

16 and 18 in the main frame of lift truck 10 is described in detail in US. Patent No. 2,762,444, issued on September 11, 1956, in the name of R. H. Gardner.

As best shown in FIG. 5, the load supporting frame 14 comprises a pair of vertical transversely spaced inwardly opening channel members 46, a pair of forwardly extending transversely spaced frame members 48 having axially aligned openings 50 therein, an upstanding transverse plate member 52 connected to the front end of frame members 48, and a pair of forwardly extending pallet legs 54 located somewhat transversely outwardly of members 48 and secured, as by welding, to the lower corner portions of plate 52. Each pallet leg 54 comprises a generally inverted U-shaped construction having an open framed end portions 56 adapted to receive a trial wheel and lift lever linkage assembly 58. The load support frame 14 is mounted in relation to main frame 12 such that plate 52 lies immediately forward of battery compartment 22, members 48 extend rearwardly beneath the main frame, and vertical members 46 extend upwardly and behind battery compartment 22 through openings 60 cut out of the horizontal base plate 62 of the main frame. A plurality of body or cover plate members, as shown in the figures, are connected to each other and to the main frame 12, and

cover the drive head assembly 16, frame 12, battery compartment 22 and parts of frame 14.

A transverse torque tube 66 is journaled in openings 50, and supports transversely outwardly of the members 48 a pair of bell crank members 68 keyed to the ends of said shaft. n the upper end of each bell crank 68 is mounted a roller 69 which is received in a short longitudinally extending and inwardly facing guide track 7% secured to and beneath floor portion 62. A forwardly extending arm of each bell crank is connected to an elongated pull rod 72 by a threaded link 73. The pull rod extends through and beneath the pocket of each inverted U-shaped leg 54 and is pivotally connected at its forward end by a pin 74 to a lifting lever 76 of each trail wheel assembly 58 which is supported for lifting movement beneath each pallet leg by means of a pivot pin 7 8 mounted in a pair of openings 83 in each pallet leg dd. Each lift lever 76 is bifurcated to receive a trail wheel 82 properly disposed within an open pocket 84 formed by the forward portion '6 of each pallet leg when the latter is disposed in a lowered position as shown in FIG. 1.

Secured to and extending upwardly in transverse spaced relation from floor 62 of the main frame is a pair of frame members 88, outwardly of each of which is mounted a pair of upper and lower rollers 901 which engage the channels of inwardly opening channel members 46 whereby to support for vertical movement in main frame 12 the load supporting frame 14. Transverse member 17 extends between .and is secured to frame members 88 adjacent the upper pair of rollers 93.

During assembly of the truck, and after the load supporting frame 14 is mounted in main frame 12 and drive motor 16 is mounted in the main frame, as described above, lift cylinder 29 is mounted centrally of plate 17, and in partial overlapping relation to drive motor 16 and drive

motor support

34, 36, following which upper-most frame plate 18 is secured to the upper ends of channels 46 while the piston rod is secured centrally of plate 18 'by the bolted connection 96. An apron @3 depends downwardly from mounting plate 18 behind cylinder 2d to protect the piston rod when it is ext-ended, and a pair of gusset plates 1% are secured forwardly of cylinder 20 between the forward flanges of channels 46 and the underside of plate 18. Connected between an eye 1% in base plate 62 and the one leg of an L-shaped bracket 1454 secured to the one channel 46 is a cylinder return tension spring 106 which functions to return the load supporting frame to a lowered position as shown in FIG. 1. Release of pressure fluid in cylinder 2% following extension thereof to elevate the load supporting frame permits spring 106 to pull load supporting

frame members

18 and 46 downwardly to return the hydraulic motor 26' to a retracted position whereby to lower the load supporting frame. A pair of side thrust rollers 114? are secured by bracket members to the outer surfaces of frame members 88 and contact the web portions of channels 46 to aid in taking up side thrust and twisting moments between the load supporting and main frames.

It will be appreciated that the foregoing construction which enables the driving and load supporting ends of the truck to be coupled together for movement and elevation of the load supporting end relative to the drive end effects a minimum length of the drive end, which is desirable, for any given length of the load supporting end.

This minimization of drive end length is a result largely of the construction by means of which the lifting and coupling assembly comprising fixed frame members 88, movable channel members 46, hydraulic motor 21 and overlying andunderlying transverse members 13 and 17, are located partially in the vertical plane of the drive motor assembly 16 and mounting

track

34, 36. This manner of construction and assembly also simplifies the construction of the drive end of such trucks, lessen the cost of the truck, and eliminates the prior problem of synchronizing a pair of transversely spaced lifting motors previously utilized in such trucks for the same purpose as hydraulic motor 26 in the present invention.

Considering the foregoing description, and particularly FIGS. 1, 3 and 4, it will be appreciated that in elevating the loadsupport assembly 14 pressure 'fiuid is directed to the bottom of hydraulic motor 29 through conduit 28 which actuates the piston rod thereof upwardly from the FIG. 1 and 3 to the FlGf i position, thereby actuating upwardly therewith channel members 46 with mounting member 18 and horizontal frame members 43, whereby torque tube 66 is actuated upwardly with frame members 48 which causes levers to be actuated from the FIG. 1 to the FIG. 4 position wherein rollers 69 are located in the extreme right-hand ends of short channels 7 0', thereby causing each rod 72 to be actuated as shown to pivot each lever 76 clockwise about the respective pins 78 as shown in EEG. 4. The lifting motion of the pair of levers 76 is synchronized through the actuation of link rods 72 and the operation of torque tube 66 ,in lifting the front end of the pallet legs 54 with

frame members

46 and 48.

In FIGS. 2 and 3 it will be noted that torque tube 66 extends through and transversely beyond frame members 48, and that levers 68 are connect-ed to shaft 66 outwardly of frame members 48; channel members 7% and actuating rods 72 are also located outwardly of frame members 48. With tlus construction, and the turn-around construction of each wheel assembly 58, described below, it is possible to adjust the spacing of pallet legs 54 transversely within predetermined limits Without the necessity of providing any different or additional parts than those illustrated in the drawing, and with a minimum reorientation of the parts already shown.

Referring especially to FIGS. 2 and 6 it will be noted that each lever 76 includes bifurcated or spaced arms 116 in which a roller 82 is mounted on a stub shaft 111), said lever being mounted for pivotal movement about pin 78 which is received in openings 86 and held in position by vertical pin 112, and having an overlying member 114 forming a part of pocket 84 and functioning as a stop limiting pivotal movement of wheel assembly 58 in a counterclockwise direction. Rod 72 is received between the sides 116 of the downwardly extending nose portion of lever 73, being retained in position by transverse pin 74 which is held in position by a vertical pin 118, The forward end of each rod 72 comprises a hollow sleeve and spacer member 120 which is adapted to receive the pin 74 and which extends transversely outwardly of the end of rod '72. At the time of assembly of the truck, or after some use thereof, the spacing of pallet legs 54 may, for example, be fixed at 24 inches (from one outer side to the other) or 27 inches. As shown in FIG. 2, pallet legs 54, rods 72 and wheel assemblies 58 are positioned with the wider available spread. The narrower spread may be accomplished in the truck of FIG. 2 by detaching each Wheel assembly from link rods 72, detaching pallet legs 54 from plate member 5-2, moving each pallet leg 54 transversely inwardly 1 /2 inches, in the above example, resecuring, as by welding or bolting, the rear end of each pallet leg to plate 52, removing pin 74, rotating each rod 72 about connector link 73, and revassemblying wheel assemblies 58 on the end of pallet legs 54 and link rods 72 by means of

pins

74 and 73. Rotation of link rods 72, as aforesaid, causes transversely extendin sleeve 12% to be projected to the opposite side of the link rod and therefore to space arms 116 of each wheel assembly towards the opposite pallet leg 54 relative to its respectvie link rod '72 rather than away from the other pallet leg relative to said link rod, as in FIGS. 2 and 6. It is, therefore, a relatively simple matter to adjust the spacing of pallet legs 54, such adjustment requiring merely detachment of wheel assemblies 58 from the pallet legs, rotation of the link rods 180, adjustment of the pallet legs 54 on supporting plate 52, and reassembly of wheel assemblies 58 in pockets 84 in the new relationship to therespective link rods 72. Heretofore, major alteration in the truck frame or other par-ts was required in order to eifect a change in the lateral spacing of the pallet arms.

Although only one embodiment of our invention has been illustrated and described, it will be apparent to those skilled in the art that changes and modifications in the adjacent the forward end thereof a pivoted trail wheel assembly, and actuating link and lever means connected to each said trail wheel assembly, said latte-r connection including a transverse member mounting said actuating linkage in eccentric relation to each said trail wheel assem bly andbeing reversible relative to said trail wheel assembly so as to dispose the latter in oppositely disposed eccentric relation to said actuating linkage, each of said load support members being reconnectable at a second position transversely of the load support frame upon a reversal in the position of said trail wheel assembly rela-' tive to the actuating linkage, as aforesaid, whereby the spacing between said pair of load support members can be varied.

2. Ina hand lift truck, the combination of a generally L-shaped forwardly extending load support frame, a generally 'L -shaped rearwardly extending main frame coupled to said load support frame, a single fluid lift cylinder means mounted vertically and longitudinally centrally of the truck and operatively connected between the coupled L-shaped frames for actuating the load support frame vertically relative to the main frame, the upstanding legs of said L-shaped frames each comprising a pair of transversely spaced members, one of which pairs is located transversely outwardly of the other pair, a pair of vertically spaced transversely extending support members connected to the respective pairs of said upstanding legs, said lift cylinder means being connected to and between said transversely extending members and located at least partially within the transverse projection of the upstanding legs, a mounting means formed in said main frame, a drive motor and wheel assembly mounted in said mounting means, said lift cylinder means being mounted at least partially within the vertical projection of said mounting means and above the horizontal plane thereof, and a battery compartment extending transversely of the truck located on the main frame immediately forwardly of said pairs of upstanding legs and of said lift cylinder means.

3. In a hand lift truck, the combination of load supporting and main frame assemblies each of generally L-shaped configuration and each having a pair of transversely spaced upstanding legs, said pairs of upstanding legs being mounted in transverse coupled relation to each other such that the load supporting frame is elevatable on and relative to the main frame, a pair of vertically spaced transversely extending members connected to respective pairs of said upstanding legs, a single longitudinally centrally located pressure fluid actuated cylinder-piston motor having opposite ends thereof connected to opposite ones of said transversely extending members and located at least partially within the transverse projection of the upstanding legs, a circular mounting means formed in said main frame, and a drive motor and wheel assembly mounted in said mounting means, said cylinder-piston motor being mounted at least partially within the vertical projection of said circular mounting means and above the horizontal plane thereof, and a battery located on the main frame immediately forwardly of said pairs of upstanding legs.

4. In a hand lift truck, the combination of a generally L-shaped forwardly extending load support frame, a generally L-shaped rearwardly extending main frame coupled to said load support frame, a single fluid lift cylinder means mounted vertically and longitudinally centrally of the truck and operatively connected between the coupled L-shaped frames for actuating the load support frame vertically relative to the main frame, the upstanding legs of said elevatable load support frame comprising a pair of outer transversely spaced members and the upstandinglegs of said'main frame comprising a pair of inner transversely spaced members coupled to said outer pair of such members, an upper transverse support member connecting the upper end portions of said outer members, a lower transverse support member spaced beneath said upper member and connected to said inner members, said single lift cylinder means being fixedly connected to said lower support member and movably connected to said upper support member and located at least partially within the transverse projection of the upstanding legs, whereby said lift cylinder means is extendable to elevate said outer pair of upstanding legs on said inner pair thereof, a battery compartment extending transversely of the truck located on the main frame immediately forwardly of said pairs of upstanding legs and of said lift cylinder means, a circular mounting means formed in said main frame, and a drive motor and wheel assembly mounted in said mounting means, said lift cylinder means being mounted at least partially within the vertical projection of said mounting means and above the horizontal plane thereof.

5. In a hand truck, the combination of a main frame, a generally L-shaped load supporting frame mounted for vertical movement in said main frame, said L-shaped 'frame including a pair of transversely spaced L-shaped lmembers, shaft means supported on the horizontal leg portions of said l -shaped members and extending transversely outwardly thereof, a pair of actuator levers mounted on the outwardly extending ends of said shaft means, guided relative to said main frame and operatively connected to a pair of lift wheel assemblies which are mounted adjacent the forward end of the load supporting frame, each operative connection including a longitudinally extending rod which is connected to the respective lift wheel assembly by means of a transversely extending member which extends outwardly of one side of said rod, said transversely extending member being adjustable with said rod so that it extends either transversely outwardly or inwardly of the respective rod, said pair of transversely extending members associated with said pair of rods being adapted to vary the transverse spacing between the lift wheel assemblies, and said horizontal leg portions of the load support frame being reconnectable at first and second positions on the load support frame corresponding to the transverse spacing of said pair of lift wheel assemblies.

6. A hand lift truck as claimed in claim 2 wherein an elongated tension spring is connected outwardly of the upstanding legs of the load support frame for lowering said latter legs and frame relative to the main frame.

7. In a battery-powered lift truck, the combination of a generally L-shaped forwardly extending load support frame, a generally L-shaped rearwardly extending main frame coupled to said load support frame, said load support frame being movable vertically relative to the main frame, a single fluid lift cylinder means mounted vertically and longitudinally centrally of the truck and operatively connected between the coupled L-shaped frames for actuating the load support frame vertically relative to the main frame, the upstanding portion of said load support frame comprising a pair of transversely spaced vertical members located transversely outwardly of a pair of transversely spaced upstanding legs of the main frame, said pairs of upstanding legs being coupled for guiding and supporting vertical movement of the load support frame, a pair of vertically spaced transversely extending support members connected to respective pairs of said upstanding legs, said lift cylinder means being connected to and between said transverse support members and located at least partially within the transverse projection of the upstanding legs, a battery compartment extending transversely of the truck located on the main frame immediately forwardly of said pairs of upstanding legs and of said lift cylinder means, and a drive motor and Wheel assembly mounted in said main frame rearwardly of said upstanding legs, said lift cylinder means being mounted at least partially within the vertical projection of said assembly and above said assembly.

8. In a hand lift truck, the combination of a generally L-shaped forwardly extending load support frame, a genenerally L-shaped rearwardly extending main frame coupled to said load support frame, a single fluid lift cylinder means mounted vertically and centrally of the truck and operatively connected between the coupled L-shaped frames for actuating the load support frame vertically relative to the main frame, the upstanding legs of said L-shaped frames each comprising a pair of trans versely spaced members, one of which pairs is located transversely outwardly of the other pair, a pair of vertically spaced transversely extending support members connected to respective pairs of said upstanding legs, said lift cylinder means being connected to and between said transversely extending members, shaft means supported from and extending transversely of each of a pair of transversely spaced horizontal leg portions of said load support frame, an actuator lever mounted on each opposite end portion of said shaft means, guided relative to said main frame and operatively connected to a pair of lift wheel assemblies mounted adjacent the forward ends of said horizontal leg portions, said operating connection including a longitudinally extending rod connected to each lift wheel assembly by means of a transversely extending member which extends outwardly of one side of said rod, said latter transversely extending member being adjustable to extend transversely outwardly or inwardly of said rod so that the transverse spacing of said pair of lift wheel assemblies is adjustable.

9. In a hand lift truck having forwardly extending pallet fork means for elevating loads on the truck, a trail wheel pallet lifting assembly connected to the end portion of each fork member by transverse pin means, said trail wheel assembly including a bifurcated lever mounted on said pin means and extending forwardly thereof, a trail wheel mounted adjacent the forward end of said lever, actuating rod means connected between the arms of and to said lever in eccentric relation to said lever, said connection including a transversely extending member connected to the end of said rod and extending outwardly thereof in one direction therefrom for holding said rod in eccentric relation to said lever when said rod is' mounted between the arms of said lever, removal of said transverse pin permitting said lever to be disassembled from said rod, whereupon said transverse member and rod may be adjusted so that the transverse member extends outwardly of said rod in the opposite direction, said lever and rod being thereuron reassembled with said transverse pin and disposing said lever and wheel in a transversely adjusted position relative to the first position thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,358,957 9/44 Barrett 254l0 2,359,493 l0/44- Schreck 2542 2,417,394 3/47 Framhein 254-2 2,615,677 10/52 Quayle 2542 A. HARRY LEVY, Primary Examiner.

PHILIP ARNOLD, Examiner.

Claims

1. IN A HAND LIFT TRUCK, THE COMBINATION OF A DRIVE HEAD AND MAIN FRAME, A PAIR OF FORWARDLY EXTENDING LOAD SUPPORT MEMBERS MOUNTED ON SAID MAIN FRAME FOR ELEVATION RELATIVE THERETO, EACH OF SAID PAIR OF MEMBERS SUPPORTING ADJACENT THE FORWARD END THEREOF A PIVOTED TRAIL WHEEL ASSEMBLY, AND ACTUATING LINK AND LEVER MEANS CONNECTED TO EACH SAID TRAIL WHEEL ASSEMBLY, SAID LATTER CONNECTION INCLUDING A TRANSVERSE MEMBER MOUNTING SAID ACTUATING LINKAGE IN ECCENTRIC RELATION TO EACH SAID TRAIL WHEEL ASSEMBLY AND BEING REVERSIBLE RELATIVE TO SAID TRAIL WHEEL ASSEMBLY SO AS TO DISPOSE THE LATTER IN OPPOSITELY DISPOSED ECCENTRIC RELATION TO SAID ACTUATING LINKAGE, EACH OF SAID LOAD SUPPORT MEMBERS BEING RECONNECTABLE AT A SECOND POSITION TRANSVERSELY OF THE LOAD SUPPORT FRAME UPON A REVERSAL IN THE POSITION OF SAID TRAIL WHEEL ASSEMBLY RELATIVE TO THE ACTUATING LINKAGE, AS AFORESAID, WHEREBY THE SPACING BETWEEN SAID PAIR OF LOAD SUPPORT MEMBERS CAN BE VARIED.