Apparatus for sensing and indicating the angular relationship between a towing and a towed vehicle

Claim 1

Apparatus for sensing and indicating the angular relationship between a towing and a towed vehicle, wherein the towing vehicle includes a ball hitch assembly comprising a ball connected to a shaft which is attached to the towing vehicle, said apparatus comprising: a variable resistor having a body portion, a shaft rotatably mounted to said body portion so that the resistance of the variable resistor is varied as the shaft is turned; a plate having an orthogonal portion and an aperture, the body part of the variable resistor being rigidly attached to said plate, said shaft protruding through the aperture therein; a second plate having a circular aperture, said second plate being mounted to the towing vehicle by sliding the shaft of the ball hitch assembly of the towing vehicle through said circular aperture, said second plate also having an orthogonal portion, said orthogonal portion having an aperture into which is placed the orthogonal portion of said first plate so as to form a hinge; a feeler rigidly connected to the shaft of the variable resistor; means for fixedly but removably attaching said feeler to the towed vehicle thereby providing for rotational movement of the shaft in relation to the body portion of said variable resistor as the towed vehicle moves in relation to the towing vehicle; and an indicator means electrically responsive to the movement between the shaft and body portions of said variable resistor for representatively indicating the angular relationship between the towing and towed vehicle.