Material or article handling – Elevator or hoist and loading or unloading means therefor – Comprising means enabling additional movement of carrier or...
Patent
1980-09-22
1983-07-12
Blix, Trygve M.
Material or article handling
Elevator or hoist and loading or unloading means therefor
Comprising means enabling additional movement of carrier or...
B66F 912
Patent
active
043927734
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates generally to a carriage assembly having a laterally shiftable fork structure and more particularly to such an assembly mounted to a mast structure of a lift truck.
2. Background Art
In the construction of vehicles, as for example a lift truck as shown in U.S. Pat. No. 3,999,675 which issued Dec. 28, 1976, to James E. Forrey et al., both vertical and horizontal force components from the fork, are commonly taken up by the top portion of the carriage assembly. Thus, it is required that the top portion of the carriage assembly by relatively large and heavy to carry the vertical force components. Because of the size and location of the top portion of the carriage assembly, forward downward vision of the operator of the lift truck can be somewhat restricted. Because of the weight of the top portion, the cost of the structure is somewhat high.
In carriage assemblies which have a side shifter, that is, a frame which shifts laterally relative to the mast assembly and carries the forks with it, it is particularly important to have clear forward and downward vision for the lift truck operator, since this allows the operator to visually follow lateral movement and downward tilting of the forks and associated load.
While some structures exist wherein the top portion of a carriage assembly does not accept any vertical forces, but only horizontal forces resulting from the moment created by a load held by the forks of such an assembly, such structures have not been utilized with a carriage assembly which includes a side shifter. U.S. Pat. No. 3,381,834, issued May 7, 1968, to C. B. Gibson, illustrates a lift truck wherein there is no vertical load accepting ability in the upper portion of the carriage assembly and where the entire vertical load upon the forks is taken up by a structure beneath the forks. Such an assembly is not readily adaptable for use with side shifting carriage assemblies.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, a load lifting apparatus has a mast assembly and a carriage assembly. The carriage assembly has an upper member and a lower member and is mounted to and translatable along the mast assembly. A side shifter, having upper and lower bars, is mounted to and laterally translatable along the upper and lower members. A generally "L" shaped tine has a generally vertical leg and a generally horizontal leg. Means are provided for mounting a top end portion of the vertical leg to transfer substantially only horizontal forces to the upper bar. Means are also provided for mounting the bottom end portion of the leg to transfer vertical forces to the lower bar. Further, means are provided for maintaining the lower bar from moving laterally away from the lower member, said means being free from interference with relative longitudinal movement between the lower bar and lower member.
A structure as set out above has the advantage that all vertical forces are taken up by the lower portion of the carriage assembly. As a result, the upper portion of the carriage assembly can be relatively small. This allows relatively free forward and downward view for an operator of a lift truck which has such a carriage assembly. Also, the ability of the assembly to lift a load is improved since the effective lever arm, from the load on the tines to the lower portion of the carriage assembly, is shorter than the effective lever arm in prior art structures (from the load to the upper portion of the carriage assembly). Further, side shifting is provided. Also, a close fit can be maintained between the lower member and the lower bar and apparatus can be provided which keeps the tine from rotating away from the side shifter and which can be easily removed to replace or repair damaged tines, or to mount tines of specialized shapes and/or sizes.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates, in perspective view, one embodiment of the present inven
REFERENCES:
patent: 2788148 (1957-04-01), Parcell
patent: 2886197 (1959-05-01), Harris
patent: 2904203 (1959-09-01), Mindrum
patent: 3066807 (1962-12-01), Draxler
patent: 3106305 (1963-10-01), Gehring
patent: 3381834 (1968-05-01), Gibson
patent: 3589541 (1971-06-01), Melin
patent: 3974927 (1976-08-01), Schuster
patent: 3999675 (1976-12-01), Forry
Blix Trygve M.
Hickman Alan J.
Sotelo Jesus D.
Towmotor Corporation
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