Abstract: A pivot joint including a mounting frame, a pivot bolt inserted through a hole on the mounting frame, and a lock nut screwed up with the pivot bolt to hold the mounting frame and the pivot bolt together, permitting the pivot bolt to be turned about its longitudinal center axis, wherein the pivot bolt has a collar stopped against the mounting frame at one side opposite to the lock nut; two washers are mounted around the pivot bolt and retained between the mounting frame and the lock nut; a plurality of corrugated plate springs are mounted around the pivot bolt and retained between the washers.

Abstract: A pivot joint including a pivot bolt, which has an elongated flat mounting rod section at one end, a screw rod section at an opposite end, which has two longitudinal planes at two opposite sides, and a collar between in the middle, a mounting frame rotatable about the screw rod section, a lock nut in threaded engagement with the screw rod section, a first packing ring mounted around the screw rod section between the mounting frame and the collar, a second packing ring mounted around the screw rod section between the mounting frame and the lock nut, a locating ring mounted around the screw rod section between the second packing ring and the lock nut and rotatable by the pivot bolt relative to the mounting frame, reversed sets of disk-like spring rings mounted around the screw rod section between the locating ring and the lock nut, and a washer mounted around the screw rod section between the spring rings and the lock nut, wherein the second packing ring has a curved flange abutting the locating ring so that th