Three-axis trailer hitch having improved rotatable coupling between vehicle and trailer

Claim 1

A trailer hitch for providing coupling about three independent axes between a towing vehicle and a trailer, comprising in combination: (a) a universal coupling having a first U-shaped yoke member, a second U-shaped yoke member, and a pair of hollow cylindrical sections joined together in the form of a cross, said first U-shaped yoke member having a base plate adapted for attachment to the towing vehicle and a pair of spaced-apart, parallel arms extending from said base plate for supporting one of said pair of joined hollow cylindrical sections for limited angular movement about a first axis; said second U-shaped yoke having a base portion and having a pair of spaced-apart, parallel arms extending from said base portion for supporting the other of said pair of joined hollow cylindrical sections for angular movement about a second axis inclined ninety degrees with respect to said first axis; (b) a first, short, hollow cylindrical member having a forward end portion securely joined to the base portion of said second U-shaped yoke member, said first, short, hollow cylindrical member extending from the base portion in a direction opposite to that of the pair of spaced-apart, parallel arms; said first, short, hollow cylindrical member having a smooth rear-end surface perpendicular to the longitudinal axis of said first, short, hollow cylindrical member; (c) a second, short, hollow cylindrical member having a smooth front-end surface perpendicular to the longitudinal axis of said second, short, hollow cylindrical member, said second, short, hollow cylindrical member having a rear-end portion adapted for secure attachment to a trailer; each of said first and second short, hollow cylindrical members having a smooth cylindrical inner wall surface forming a bore; (d) a hollow, cylindrical sleeve member coaxially positioned within and extending between said first and second short, hollow cylindrical members, said hollow, cylindrical sleeve member having a diameter slightly less than the diameter of the bores of said first and second short, hollow cylindrical members, and a length less than the total length of said first and second short, hollow cylindrical members; and (e) a bolt having a head at one end and a threaded portion at its opposite end, said bolt extending axially between the opposite ends of said first and second short, hollow cylindrical members and through the center of said hollow, cylindrical sleeve member to retain the smooth rear-end surface of said first short, hollow cylindrical member in abutment with the smooth front-end surface of said second short, hollow cylindrical member; said hollow, cylindrical sleeve member maintaining axial alignment between said first and second short, hollow cylindrical members and providing a smooth bearing surface for relative rotation of said first short, hollow cylindrical member with respect to said second short, hollow cylindrical member about a longitudinal axis perpendicular to said second axis.