Abstract: A plate chain conveyor assembly including a plurality of plate members each having first and second opposite ends, a single hinge eye being provided at the first end of each plate member and two juxtaposed hinged eyes being provided at the second end of each plate member. Plate members are disposed adjacent one another such that the single hinge eye of each plate interengages with the two juxtaposed hinge eyes of an adjacent plate member to form a passage therethrough. A hinge bolt is disposed in each passage formed by the interengaged hinge eyes. Each hinge bolt has cylindrical ends connected to a center section. The center section has a cross section which changes from a substantially circularly shaped center portion to a substantially lens shaped cross section towards each of the cylindrical ends.