Abstract: A self-locking trailer hitch assembly includes an elongated housing attachable to the draw bar of a towed vehicle, and the housing includes an attachment end and an opposite socket which is shaped to receive a vertically-projecting ball member. The ball member is mounted to the draw bar at the rear of the towing vehicle. Disposed within the housing adjacent the socket is a jaw pivotable on a horizontal axis so that the jaw can be pivoted to a ball locking position for holding and retaining the ball member within the socket and also pivotable to a ball releasing position for unlocking and releasing the ball member from the socket so that the towed vehicle can be uncoupled from the towing vehicle. A unique releasing function is provided by a manually-operable latch which disengages the jaw from the ball locking position in order to facilitate removal of the ball member from the socket, but manual operation of the latch is not required to seat and positively lock the ball member within the socket.

Abstract: A standard ball and socket type of trailer hitch assembly is modified so as to provide means for automatically and positively locking the trailer hitch each time the trailer hitch ball is inserted into the trailer hitch socket. The socket receptacle of the trailer hitch is modified to receive a push rod which is actuated by contact with the ball of the hitch and in turn causes the latch to positively lock in place without requiring the operator to remember to move the latch into a positive locking position.