US2670867A

US2670867A - Lift truck with lazy tong pusher

Info

Publication number: US2670867A
Application number: US162865A
Authority: US
Inventors: Warren H Thompson
Original assignee: Towmotor Corp
Current assignee: Caterpillar Industrial Inc
Priority date: 1950-05-19
Filing date: 1950-05-19
Publication date: 1954-03-02
Anticipated expiration: 1971-03-02

Description

March 1954 w. H. THOMPSON LIFT TRUCK WITH LAZY TONG PUSHER INVENTOR.

TUBA/75 2 Sheets-Sheet l Original Filed July 8, .1948

WARRfN/i THOMPSON Patented Mar. 2, 1954 LIFT TRUCK WITH LAZY TONG PUSHER Warren H. Thompson,

to Towmotor corporation of Ohio Wicklifie, Ohio, assignor Corporation, Cleveland, Ohio, a

Continuation of application Serial No. 37,711,

July 8, 1948. This ap Serial No. 162,865

' 3 Claims.

This invention relates broadly to lift trucks and more specifically to improvements in pushers for ejecting the work from the load-carrying platform. This application is a continuation of my co-pending application, Serial No. 37,711, filed July 8, 1948, for Lazy Tong Pusher for Industrial Trucks, now forfeited.

One of the objects of the invention is to provide a pusher plate actuating mechanism which is designed to afford free access to the vehicle and avoid the hazard of injury to the operator by elimination of such parts as customarily traverse the zone of his activity during the elevation of the load. To this end the invention contemplates a pair of lazy tongs nested, in their closed position, forward the steering column and distensible the length of the forks. The lazy tongs are actuated by linkage coupled with a hydraulic plication May 19, 1950,

ram which is carried by the elevating mechanism and likewise disposed forwardly of the driver.

Another object of the invention is to provide a coupling between the pusher and lazy tongs which will support the plate in normal relation to the load-carrying platform throughout the actuation of the pusher.

Another object of the invention is to provide linkage for actuating the lazy tongs which effect the operation thereof with a minimum effort.

Other objects of the invention reside in the provision of a pusher which is efiicient of operation, economic of manufacture, sturdy of structure, and adapted for interchangeable assembly on vehicles of variable size and design. 7

Other objects and advantages more or less ancillary to the foregoing, and the manner in which all the various objects are realized, will appear in the following description, which, considered in connection with the accompanying drawings, sets forththe preferred embodiment of the invention.

Referring to the drawings:

Fig. 1 is a side elevational view of the improved pusher in its distended position;

Fig. 2 is a similar View shown upon an enlarged scale with the lazy tongs in their retracted position, certain of the parts in this view being broken away and shown in section in the interest of clarity;

Fig. 3 is a front elevational view of a fragmentary portion of the pusher;

Fig. 4 is a vertical sectional view through the lazy tongs and. supporting frame therefor, the section being taken on a plane indicated by the line 4-4 in Fig. 2; and,

Fig. 5 is a transverse sectional view through the lazy tongs guide rail and carriage, the sec- 2 tion being taken on a plane indicated by the line 5-5 in Fig. 2.

Referring first toFig. l, the vehicle for which the improved pusher is designed may be of any conventional form, such, for example, as the Industrial Truck disclosed in Letters Patent of the United States No. 2,418,661, issued April 8, 1947, to Dwight M. Palm. The vehicle comprises a frame Ill supported on dirigible wheels I I, a steering gear l2 therefor, a fixed mast l3 adjacent the front wheels, a reciprocable slide I4 therein, and a load-carrying platform or fork I5 carried thereby. The vehicle further includes a hydraulic pump and lift cylinder, not shown, for elevating the slide, and a multi-valve operating unit I 6 for the control of the lift cylinder and other operating mechanisms in the machine. The pusher is supported by a carriag I! which is mounted on the slide I4 and constructed for the retention of the fork I5. The carriage is formed with cross members I8 having the ends thereof disposed beyond the plane of the side walls of each stanchion of the mast I3. The ends of the cross members retain the frames I9 that constitute the supporting elements for the hydraulic jacks, lazy tongs, and operating linkage therefor. The frames are disposed in parallel relation with each other on opposite sides of the vehicle,.the inner ends thereof terminating forward the opening that'forms the entry to the vehicle. In detail, each frame comprises a top rail 20, a bottom rail 2|, and an intermediate end member 22. The end member is formed from a pair of channel irons mounted withthe center webs thereof in contiguous relation and with their flanged portions normal to the plane of the lazy tongs. The channels as thus arranged form a track for guiding a carriage 23 which is pivotally connected to the free end of the upper link of the lazy tongs 24. The lower terminating link of the lazy tongs is pivoted in a bracket 25 welded or otherwise alfixed to the end member 22. The carriage comprises a pair of plates 21 disposed adjacent the outer edges of the flanges and fabricated for the reception of stub axles 28 having rollers 29 thereon which engage the inner walls of the flanges.

The carriage is provided to facilitate the translation of the free link of the lazy tongs and form a thrust bearing therefor during the actuation of the pusher. The end member 22 is provided with a lug 30 subjacent the bracket 25 which is cross drilled for the pivotal support of a hydraulic piston cylinder assembly 3 I. The cylinder is formed with ports 32 in the opposed ends thereof to facilitate the reciprocative movement of the piston when pressure fluid is admitted successively through conduits 33 and 34 coupled with the ports and the control valve Hi. The piston rod 35 is pivotally connected to the lower end of an arm 36' mounted for pendulous movement on the rail 20 of the frame l9, and this arm is connected in turn with a drag link 37 coupled with the first section of the lazy tongs. The lazy tongs are preferably constructed from a series of relatively heavy bars 38 pivotally connected at their ends and central portions to lighter cross bars 39 disposed on the opposed sides thereof. The upper forward link 49 of the lazy tongs is pivoted to a carriage ll similar in structure, and function to the carriage 23. The carriage il is guided in a track 42 formed in the pusher plate t3, and the lower outer link 44 is pivoted in a bracket 45 welded on the plate adjacent the lower end thereof.

Although the drag link as shown herein is connected to an extended portion of each of the bars 39, it will be recognized that the link may be connected to an elongated end of the companion bar 38 which is proportioned relative to the piston throw to provide the requisite distention of the lazy tongs.

In operation, when the valve 16 is adjusted to admit pressure fluid to the rearward portion of the cylinder the piston will be advanced and will swing the arm 36 forwardly, thus eifectuating the distention of the lazy tongs and the removal of the work supported on the fork 15. When the valve is reversed, pressure fluid will enter the forward end of the cylinder and effect the retraction of the lazy tongs. It will be recognized that the carriages 23 and M will maintain the pusher plate normal to the fork and parallel the medial axis of the lazy tongs as the angular relation of the cross links is changed during the operation of the pusher. It will be further noted that the structure of the linkage of the lazy tongs will accommodate the nesting thereof into such compact form that the assembly may be readily mounted on a vehicle intermediate the elevating mechanism and the opening defining the entrance to the vehicle.

Although the foregoing description is necessarily of a detailed character, in order that the invention may be completely set forth, it is to be understood that the specific terminology is not intended to be restrictive or confining, and that various rearrangements of parts and modifications of detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

What is claimed is:

1. In a lift truck, a chassis, a mast mounted forwardly on said chassis, a carriage movable along said mast, supports extending rearwardly from each side of said carriage and straddling said mast, lazy tongs anchored at one end to a rearward portion of said supports and joined at their forward ends to a pusher plate, and motor means for extending and retracting said lazy tongs.

2. In a lift truck, a chassis, a mast mounted forwardly on said chassis, a carriage movable along said mast, a driver's compartment rearwardly of said mast, supports extending rearwardly from each side of said carriage and straddling said mast, said supports stopping short of the forward wall of said drivers compartment, lazy tongs anchored at one end to a rearward portion of said supports and joined at their forward ends to a pusher plate and motor means for extending and retracting said lazy tongs.

3. In a lift truck embodying a chassis, a mast on the forward end thereof, a carriage movable vertically along said mast, a horizontal load-carrying platform extending forwardly from said carriage, and a truck body on said chassis having a drivers station formed therein, said drivers station being disposed rearwardly of said mast, a pusher for discharging material on the loadcarrying platform comprising a vertically disposed pusher plate forward of said carriage and above said platform, vertically disposed rails mounted for vertical movement with said carriage and disposed adjacent the forward end of said driver's station when the carriage is in its lowered position, multiple link lazy tong assemblies pivotally connected at one end to said rails and at the other end to said pusher plate, a piston and cylinder assembly pivotally mounted at one end upon said rail subjacent one of said lazy tong assemblies, means pivotally connecting the other end of said piston and cylinder assembly to a link in said lazy tong assemblies, said lazy tong assemblies being disposed between said rail and the rear of said platform while in their retracted position and between said rail and the forward end of said platform while in their distended position, and roller means on said lazy tong assemblies engaged with and vertically movable upon said rail and said pusher plate for supporting the plate in normal relation to said platform.

WARREN H. THOMPSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,977,785 Wheelock Oct. 23, 1934 2,256,454 Bomar -2 Sept. 16, 1941 2,412,155 Jessen Dec. 3, 1946 2,418,661 Palm Apr. 8, 1947 2,583,977 Turner Jan. 29, 1952 FOREIGN PATENTS Number Country Date 474,968 Germany Apr. 17, 1929 323,812 Italy Jan. 9, 1935