Clamping and lifting mechanism

Abstract

A clamp for clampingly engaging a portion of a workpiece and for lifting the workpiece from a work surface. The clamp comprises a fluid actuated pistol and cylinder assembly, a frame assembly, first and second clamp arms supported by said frame assembly for pivotal movement about respective first and second pivot axes and axial movement parallel to said longitudinal axis between an unclamped position and a clamped and lifted position, first and second pivot pins respectively defining said first and second pivot axes, first and second slider members respectively supported in first and second tracks for axial movement relative to frame assembly and respectively supporting said first and second pivot pins for axial movement along said first and second tracks relative to said frame assembly, first and second link pins supported proximate the opposite ends of said first and second clamp arms, respectively, said first link pin being movable along said first arcuate track and said first track and said second link pin being movable along said second arcuate track and said second track, first and second link members connecting said first and second link pins, respectively, to the piston such that movement of piston between said extended position and said retracted position causes movement of said first and second clamp arms between the unclamped position and the clamped and lifted position. As the piston is moved from the extended position to an intermediate position, the clamp arms are pivoted to a clamped position. As the piston is moved from the intermediate position to the retracted position, the clamp arms are moved to the clamped and lifted position and the slider members are moved in the tracks, respectively, so that said arcuate portions are substantially misaligned with said arcuate tracks to prevent the clamp arms from moving to an unclamped position.