Patent ID: 7537427

Claim:
A clamping apparatus for lifting a rectangular layer of items on a pallet comprising: a frame; four clamping arms pivotably mounted on the frame for pivoting with respect to the frame with a single degree of freedom and positioned on the frame so as to be able to grasp a rectangular layer of item on a pallet from four sides of the layer, each clamping arm including a contact portion for contacting a side of the layer to be lifted, each clamping arm defining a four-bar linkage which controls an angle of the contact portion with respect to the vertical as the clamping arm pivots with respect to the frame, the four-bar linkage of each clamping arm including a lever portion pivotably connected to the frame and to the contact portion of the clamping arm, and a rigid control rod for adjusting the angle of the contact portion with respect to the vertical extending alongside the lever portion and having an upper end pivotable with respect to the frame and a lower end pivotable with respect to the contact portion; and a plurality of drive mechanisms connected to the clamping arms to pivot the clamping arms with respect to the frame.