Abstract: Apparatus are disclosed for securing an implement to a rigid longitudinally extended lifting member. A representative embodiment comprises a clamp that can be mounted to a forklift implement and/or socket for receiving a lifting member. A working surface engages the lifting surface of the lifting member. A cam is pivotably mounted on an axis transverse to and displaced from the working surface. The cam has an outwardly radiating spiraled engagement lobe that presses against the under-surface of the lifting member so as to press the lifting member between the working surface and the cam. Thus, the cam allows the clamp to be moved rearwardly but not forwardly on the lifting member. The cam, which is biased, can be characterized by having a fixed axis, being self-locking, and/or having a constant contact angle with the underside of the lifting member.