Patent Application
20190023547
Layer-picking clamp assemblies of various different types have previously been used in the load-handling industry to reach sideways from a lift truck or other load-handling machine so as to position a downwardly extending load-engaging clamp into alignment over a load, selectively lower the clamp so as to surround an upper portion of the load laterally, and then clamp and lift the upper portion vertically to separate it from a lower portion of the load.
Previous types of such layer-picking clamp assemblies, exemplified in U.S. Pat. Nos. 6,135,704 and 7,841,822, have utilized a laterally rotational boom assembly to rotate a suspended, downwardly-directed load-engaging clamp into a position horizontally aligned above a layered load located remotely from the lift truck. However, the laterally rotational boom assemblies of both of these examples limit the ability of the clamp assembly to transfer the load from the boom to the forks of a counterbalanced lift truck upon which the boom is mounted without tipping the lift truck, unless the weight of the load is greatly limited below the normal capacity of the lift truck. Rotation of such a boom assembly when loaded also creates a large moment of inertia which further limits the lift truck's counterbalanced load carrying capacity.
Another previous type of layer-picking clamp assembly, exemplified in U.S. Pat. No. 5,516,255, utilizes a non-rotational, laterally extensible boom assembly to position a load-engaging clamp above a layered load. However, such boom assembly likewise prevents the ability of the clamp assembly to transfer a load from the boom to the forks of the counterbalanced lift truck upon which the boom is mounted. Such boom assembly also disadvantageously requires a large forwardly-positioned counterweight on the opposite side of the lift truck which limits the counterbalanced forward tipping stability of the lift truck.
A need therefore exists for an improved structure which minimizes the foregoing drawbacks of existing layer-picking load clamping assemblies.
An exemplary layer-picking load clamp assembly, indicated generally as 10, is shown in
The lifting chain 14 is connected to, and vertically movably supports, a forwardly-projecting load-lifting arm assembly 16 which may comprise a rectangular frame as shown, or any other suitable vertically movable load lifting structure. The load-lifting arm assembly 16 supports a bidirectional side-shifting assembly having a selectively reversible hydraulically driven rotary motor drive assembly 18 equipped with a selectively operable hydraulic brake. The motor drive assembly 18 is preferably capable of selectively bidirectionally driving or braking a conventional toothed rack and pinion gear assembly, shown schematically as 20, 22 in
Vertically supported by the rack assembly 23b, and movable in unison therewith, is an exemplary layer-picking load clamping assembly generally indicated as 24 mountable transversely to the lift truck mast 12 as shown in
Optionally, hydraulic cylinders such as 29a shown in
Preferably, but not necessarily, mounted transversely to the foregoing load clamping assembly 24 is a separate load clamping assembly 30 for selectively engaging the front and rear sides of the load, transversely to the direction of engagement of the load clamping assembly 24. Such engagement can be controlled by separate hydraulic piston rods 32 which selectively extend or retract the clamping assembly 30. The separate clamping assembly 30 is preferably supported telescopically by structural tubes such as 34 and slidable rods such as 36 in a direction perpendicular to the previously described tubes 26.
Depending upon the transverse length dimensions of the loads to be handled, or other variables, the foregoing extensible rack assembly 23a, 23b may or may not require multiple telescopically extensible overlapping rack stages. However, if the expected transverse lengths of the loads to be handled, and/or the expected degree of transverse extension of the loads, are large enough to require one or more telescopic rack stages, each rack stage should preferably have a length which is substantially within the transverse width dimension of the lift truck or other support upon which the rack assembly is mounted, as exemplified in
Conventional multi-stage telescopic hydraulic piston and cylinder designs are alternatively usable in the present invention in place of rack and pinion technology, although not as effectively because of more limited degrees of retraction of such piston and cylinder structures. However, all of the foregoing existing telescopic types of designs described herein can provide significant improvements relative to presently known layer-picking load handling techniques.
The terms and expressions which have been employed in the foregoing specification are used therein as terms of descriptive examples, and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.
