Patent ID: 7674109

Claim:
A pusher plate for moving materials to be heated thereon through a pusher furnace having a guide rail which extends through at least one heating section of the furnace and defines an axis of travel of the pusher plate; the pusher plate comprising: a body having a leading face, a trailing face and a lower surface; and a groove formed in the pusher plate which extends upwardly from the lower surface from the leading face to the trailing face; wherein the groove has a first section and a second section which is laterally wider than the first section so that the groove has a shape which allows limited rotation of the pusher plate about a generally vertical axis during travel of the pusher plate along the axis of travel with the guide rail disposed in the groove; and wherein when the guide rail is disposed in the groove, the guide rail extends continuously from the leading face to the trailing face of the body and the pusher plate is rotatable about the generally vertical axis at least 6° and no more than 20°.