Locking means for clamps

Claim 1

A lock apparatus for a clamp, said clamp having a clamp body, a clamping piece rotatably pivoted at its base end on said clamp body, an abutment plate affixed to said clamp body opposite the clamping piece, and lifting means pivotally attached to said clamp body and to said clamping piece, whereby said clamping piece will rotate in the clamping direction toward the abutment plate when the clamp body is suspended by the lifting means and the item to be held will be clamped therebetween, said lock apparatus comprising a pair of base cam members located on the base end of said clamp piece eccentric with regard to each other and the pivotal axis of the base end portion of the clamp piece, a lock cam comprising a pair of lock cam members eccentric with regard to each other rotatably mounted for rotation between two positions on the clamp body at a position adjacent the base end of the clamp piece, one of said lock cam members engaging one of said base cam members when the lock cam is rotated in one direction, and the other of said lock cam members engaging the other of said cam members when the lock cam is rotated in the opposite direction, whereby movement of the clamping piece is restricted and said clamping piece is locked into position, a lever mounted on the clamp body with its fixed base end pivoted adjacent the lock cam, and a spring attached between the free end of the lever and the lock cam, whereby moving the lever upward will cause the lock cam to rotate in one direction and moving the lever downward will cause the lock cam to rotate in the opposite direction.