Abstract: A fifth wheel assembly for coupling tractor and trailer units includes an improved trunnion bracket, comprising a pair of forged bearing caps having an inverted, U-shaped configuration, with bearing sleeves fixedly mounted therein. In sliding fifth wheel embodiments of the present invention, the bearing caps are mounted on rectangular channels fabricated from two L-shaped channel members with a flat plate attached to the upper edges of the L-shaped channels. An improved plunger is provided for adjustably connecting the trunnioned fifth wheel assembly with a base plate on which slotted racks have been mounted, and comprises a forged, two-prong construction with internal guides which minimizes structural disruption in the channels to provide greater strength. Adjustable stops are mounted on the exterior ends of the plungers, and abut the exterior sides of the racks to accurately maintain the plungers in a locked position.

Abstract: A fifth wheel hitch includes a kingpin locking mechanism having a pair of pivoting locking jaws which form a socket in which the kingpin is retained. An adjustment device varies the angular position of the closed jaws to vary the side-to-side dimension of the socket, and thereby compensate for side wear in the hitch. A stationary, semicircular bearing is fixedly mounted in the hitch to form a portion of the forward half of the socket, such that pivotal adjustment of the closed jaws also varies the fore-to-aft dimension of the socket, and thereby compensate for end wear in the hitch.

Abstract: A support for a tilt stabilizing fifth wheel hitch that connects a truck tractor to a trailer, the fifth wheel plate being on a movable frame having a pair of convex shoes connected by a tie rod and resting on concave bearing plates on a fixed frame, the movable frame being movable on the fixed frame toward either of two opposite extreme positions from an intermediate neutral position. The movable frame is biased away from these extreme positions toward the intermediate position by variable force biasing means, preferably coil compression springs on said tie rod, which apply increasing biasing force with increased movement of the movable frame toward one of said extreme positions, thereby enabling the truck driver to "sense" or "feel" the tilted condition of his trailer relative to his tractor during operation.