Abstract: A locking and unlocking apparatus using an engagement pin with beveled surfaces designed to be inserted between two bodies. As the engagement pin is extended axially into a gap between the two bodies, it moves in a transverse direction to wedge tightly between the first and second body, locking them tightly together. When the engagement pin is retracted, the second body is able to move relative to the first body. A plurality of engagement surfaces placed into one of the bodies allows the mechanism to be locked into a plurality of set positions. These engagement surfaces on the first and second bodies also serve to locate the engagement pin when in the fully locked position, thereby reducing the need for tight tolerances.