Abstract: Apparatus for supplying heat and pressure to a corrugated paper board comprising heated means for supporting a web of the board as it is drawn thereover, an endless belt whose lower flight is adapted to overlie the web while it is drawn over said heated means and a plurality of freely rotatable transversely extending parallel longitudinally spaced rolls engaging the upper surface of the lower flight of said belt, at least some of said rolls being journaled in bearings located in pivoted levers, there being resilient spring means for applying a variable force to said levers, whereby an adjustment of the effective weight of at least some of the rolls on said belt may be made.