Abstract: A lock valve is provided on a conventional, mechanical lock member to add additional suspension by negative pressure in the socket created because of the intimate fit of the socket. The lock valve has a valve biased to a first position where the valve does not permit the ingress of air. When the valve is urged away from the first position to a second position, such as by pressing the lock valve inward toward the lock assembly, the mechanical locking member is released and the lock valve is opened to permit the ingress of air. As a result, the mechanical locking member and the negative pressure are simultaneously released.