Rear wheel steering system

Claim 1

In a tractor-trailer combination: a. a towing vehicle; b. a trailer having a forward end adapted to be pivotally connected to said towing vehicle, said trailer having an elongated frame with a pair of spaced longitudinally extending side members connected by a plurality of longitudinally spaced transverse cross members; c. a frame member fixed on the trailer frame adjacent a rear end thereof and extending under each of the trailer frame side members, said frame member having a downwardly facing bearing surface; d. a rear wheel assembly having a mounting member with load carrying axles having rotatable ground engaging wheels, said mounting member being resiliently supported by said axles, said mounting member being under said frame member and having an upwardly facing bearing surface engaging the downwardly facing bearing surface of said frame member; e. means on said frame member and mounting member pivotally connecting same together for rotative movement of said mounting member on a vertical axis centrally of the rear wheel assembly and on a longitudinal center of the trailer frame; f. laterally spaced fluid actuated extensible members each having one end pivotally connected to a leading portion of the mounting member and the other end pivotally connected to the frame of the trailer forwardly of said mounting member and extension of one and contraction of the other extensible members operates to rotate the rear wheel assembly about said vertical axis; g. said mounting member having lock recesses each substantially spaced outwardly from said vertical axis; h. lock structures on the frame member and an end having a lock tongue registering with a respective lock recess when the rear wheel assembly is in position for movement of the trailer in a straight longitudinal line and normally engaged in said lock recesses to retain the rear wheel assembly in said position; i. means controlled from within the towing vehicle and operative to simultaneously release the lock tongues from the lock recesses to permit turning of the rear wheel assembly about said vertical axis; and j. means controlled from within the towing vehicle and operative to selectively apply fluid pressure to said pair of extensible members to turn the rear wheel assembly about said vertical axis for steering the rear end of the trailer.