Anti-friction composite with metal backing of rigid prongs and lubricant overlay

#This invention relates generally to improvements in anti-friction composites and in one aspect relates to anti-friction composites in the form of replaceable pressure shoes positionable on stationary platens of continuous presses used in the manufacture of consolidated board-like products such as fiberboard. Composites comprised of layers of solid lubricants such as polytetrafluoroethylenes bonded to metal backing members have long been used to reduce sliding friction between machinery components. For example, in Malarkey, U.S. Pat. No. 3,215,065, there is disclosed a continuous press apparatus useful for the manufacture of laminated beams and the like. The apparatus includes a pair of opposed, traveling belt runs (in the form of continuous metal bands) for moving material therethrough and stationary platens or pressure application members for urging the belt runs together. To facilitate sliding of the belts across the platens, each platen includes a low-coefficient-of-friction surfacing means comprising a series of plastic-coated shoes set end-to-end. The illustrated shoes are comprised of a backing plate and a tetrafluoroethylene sheet bonded thereto. Malarkey U.S. Pat. No. 2,918,307 and Knapp U.S. Pat. No. 3,215,065 disclose other continuous presses incorporating anti-friction surfacing means on stationary platens.

#It is an object of this invention to provide anti-friction composites useful, for example, as pressure shoes (or "wear pads") in continuous presses of the type just discussed and in other applications, which composites have high load-bearing capabilities, are capable of withstanding high temperatures, exhibit good heat transfer characteristics, are so constructed that they maintain their physical shape and integrity despite any tendency of the anti-friction surfacing material to undergo plastic flow under prolonged application of heat and stress.

#In one of its aspects, this invention is directed to a heat-transmitting, anit-friction composite comprising a metal backing member overlaid with a low-coefficient-of-friction sheet comprised of a solid lubricant, such as polytetrofluoroethylene (hereinafter abbreviated "PTFE"). The backing sheet carries thereon a multiplicity of rigid metal prongs projecting transversely from one of its faces. The overlay sheet is impaled on the prongs, and is preferably adhesively bonded to the backing member. The prongs extend through the overlay sheet and have their tips substantially coincident with the face of the overlay sheet remote from the backing member. The prongs serve to resist plastic flow of the overlay sheet when it is subject to stresses parallel to the plane of the sheet, and also serve as paths for efficiently conducting heat through the overlay sheet. Still further, the prongs serve to mechanically connect the overlay to the backing member. Preferably, the backing member is a thin brass or bronze plate that has been perforated to form the prongs carried thereon.

#The foregoing and further objects and various advantages of the present invention will become apparent to those skilled in the art from the following detailed description and appended drawings, wherein:

#FIG. 1 is a partially fragmented isometric view of an anti-friction pressure shoe of this invention.

#FIG. 2 is a plan view of an area of the pressure shoe of FIG. 1 with a portion of the anti-friction surfacing layer removed to expose the underlying structure.