Belt-type particleboard press

Claim 1

In a belt-type press for making particleboard, including a preliminary station for prepressing a mass of wood particles and binder into a mat, a final station for converting said mat into a rigid particleboard, and an intervening central station wherein said mat is continuously compacted between confronting stretches of a pair of conveyor belts entraining said mat along a straight horizontal path under pressure from an upper platen and a lower platen bracketing said stretches between them, the pressure exerted by said platens upon said mat reaching a peak in an upstream zone, decreasing in an intermediate zone and leveling off in a downstream zone of said path, said platens being mounted on a frame structure with interposition of a set of actuators for generating said pressure, the improvement wherein said frame structure comprises a multiplicity of substantially identical sheet-steel frame elements disposed in parallel vertical planes perpendicular to said path, some of said frame elements standing alone to form single-element supports, other of said frame elements being juxtaposed to form plural-element supports, said single-element supports being disposed in said downstream zone, several of said plural-element supports being disposed in each of said intermediate and upstream zones, said supports being spaced apart along said path by distances increasing progressively from an upstream end of said path to a downstream end thereof, said frame elements being provided with mutually aligned windows traversed by said platens, said stretches and said mat, said actuators being mounted in groups in said windows, the number of actuators per support being greater near said upstream end than near said downstream end.