Belt-type particleboard press

In a continuous belt press having:

• a frame having horizontally extending and vertically spaced upper and lower platens defining a horizontally extending gap having an upstream end and a downstream end;
• vertically spaced upper and lower upstream drums rotatable on the frame about respective horizontal drum axes at the upstream end;
• vertically spaced upper and lower downstream drums rotatable on the frame about respective horizontal drum axes at the downstream end;
• upper and lower endless steel belts spanned over the respective upper and lower drums and each having a working stretch lying between the platens and a return stretch;
• upper and lower sets of rollers engaged between the working stretches and the respective platens;
• and
• means connected to the drums for advancing the belts to move the working stretches horizontally in a transport direction to displace a workpiece in the direction through the gap, the improvement wherein
• each belt further has a pair of edges projecting transversely past the respective rollers, and
• at least one of the drums of each of the belts has a substantially cylindrical central region of a predetermined central diameter bearing through the respective rollers on the working stretch of the respective belt and a pair of edge formations of smaller diameter than the central-region diameter lying outside the central region and in engagement with the edges of the respective belt.