Lift truck clamp for handling stacked loads of different sizes

Claim 1

A load-handling clamp adapted to be mounted upon the lifting apparatus of a lift truck, comprising: (a) a frame adapted to be mounted upon said lifting apparatus so as to be selectively movable vertically by said lifting apparatus; (b) first and second selectively openable and closable opposing clamping assemblies mounted upon said frame, the first clamping assembly comprising at least a pair of clamp arms movable separately from each other relative to said frame selectively toward and away from the second clamping assembly; (c) a pair of fluid power actuators, each associated with a respective clamp arm, for moving said clamp arms separately from each other selectively toward and away from the second clamping assembly; (d) a source of pressurized fluid connected to said pair of fluid power actuators for selectively causing said actuators to move said clamp arms toward said second clamping assembly by the supply of respective flows of fluid to said actuators; (e) flow-regulating means connected to said pair of actuators for regulating said respective flows of fluid so as to cause the respective movements of said pair of clamp arms, in a direction toward said second clamping assembly, to be simultaneous with each other; and (f) override means for overriding said flow-regulating means, automatically in response to the attainment of a predetermined clamping force by one of said pair of clamp arms, by permitting the other of said pair of clamp arms to move in a direction toward said second clamping assembly without simultaneous movement in said direction by both of said pair of clamp arms.