A device for preventing unauthorized intentional uncoupling or accidental uncoupling of a trailer from a towing vehicle. The threaded shaft of the ball slides through an upper housing allowing the upper housing to contain the shoulder of the ball so that the ball and upper housing can be mounted to a tow bar by inserting the threaded shaft of the tow ball through the aperture in a tow bar and then screwing a flanged nut onto the threaded shaft. A lower housing is then placed around the flanged nut and bolted to the upper housing so that the tow bar and the flanged portion of the flanged nut are sandwiched between the upper and lower housings. There is a yoke which encircles the shank of the tow ball, the dimensions of which make it impossible for it to slide over the ball. There is a locking hat which is placed over the trailer tongue ball socket having legs extending vertically downward allowing it to be locked to the yoke. Once in locked position, the trailer hitch cannot be disengaged without first unlocking and removing the locking hat. The locking hat and yoke do not limit the inherent rotation of the socket about the ball.

An attachment bolt extends upwardly through a support member and threadedly engages the ball component of a coupling apparatus. A locking member extends downwardly through the ball component and cammingly engages the attachment bolt with the pitch different than the threaded engagement between the ball component and the attachment bolt. Engagement of the ball component within a complemental coupler component prevents access to and removal of the locking member.

The ball member of a trailer hitch is bolted to a tongue piece and is coaxially surrounded at its base by a raised rim integrally formed with the tongue piece. A ball cover is pivotally mounted on the tongue piece and is movable from an open position to a closed position covering the ball. Means are provided for locking the cover in the closed position so that the cover prevents the trailer socket member from disengaging from the ball and together with the rim prevents the ball from disengaging with the tongue piece either vertically or horizontally.

An anti-theft, safety device is disclosed for use with ball and socket trailer hitches comprising a base plate clamped to the tow bar near the ball, a post attached at one end to the base plate that extends vertically from the tow bar adjacent to the ball and socket, an upper plate through which the post extends that moves vertically and rotates with respect to the post, a bushing with an opening in register with the opening in the upper plate through which the post extends, both the post and the bushing having transverse openings through which a lock bolt may be passed when the holes are aligned so that the upper plate will be held over the socket to prevent the socket from being disconnected from the ball.

A self aligning hitch arrangement for attachment to the drawbar of a towing vehicle for lifting and aligning a trailer tongue into place on a towing ball includes a mounting plate attachable to the drawbar and having side members which support a horizontal transverse pivot in front of (i.e. on the vehicle side of) the ball. A ramp member supported by the pivot has a ramp plate with its front edge spaced behind the ball member, and is pivotable between a raised position in which the plate lies at a suitable angle for lifting the trailer tongue onto the ball, and a lowered position in which the plate lies at a steeper angle and allows the tongue to fall onto the ball. The ramp member also has diverging flanges to guide the trailer tongue laterally into position over the ball. A latch carried by the side members can hold the ramp member in its raised position and has an abutment which is struck by the tongue as this becomes located over the ball, causing it to release the ramp member and allowing this to fall to its lowered position while the tongue falls onto the ball.