Abstract: A towing arm is provided for use in a tow bar assembly that connects a towed vehicle to a towing vehicle. The towing arm has an inner leg and an outer leg so that it can move telescopically between a collapsed position which is suitable for storage and an extended position for towing. When connected between a towing vehicle and a towed vehicle, the towing arm will automatically lock in the extended position as the towing vehicle is pulled away from the towed vehicle. The locking feature is accomplished by a slideable collar that moves between a locked position and a released position. When in the locked position, the collar holds catches in place between the outer leg and grooves in the inner leg, thereby locking the legs in fixed relation to each other. When in the collar is moved to the released position, the legs are free to telescope relative to each other. The catches have saddle-shaped surfaces to fit the contours of the grooves. The grooves only partially encircle the inner leg.

Abstract: A release tool is provided to aid in the unlocking of extending towing arms. The tool is adapted to fit a tow bar assembly that has a telescoping towing arm which is locked in an extended position by a slideable collar. The collar is moveable between a locked position and a released position. When in the locked position, the collar holds catches in engagement with legs of the towing arm to hold the legs fixed relative to each other. When in the released position, the legs are free to telescope relative to each other. Stress can build-up in the towing arms making it difficult to move the collar from the locked position to the released position. The release tool of the present invention provides a mechanical advantage to aid in the movement of the collar from the locked position to the released position. A cam surface on the tool engages the collar and moves it from the locked position to the released position as a handle is rotated about a fulcrum means.