Corrugating machine with a flexible vessel pressure applying means

A corrugating machine in which a continuous single-faced corrugated board consisting of a corrugated sheet glued on one face to a first flat sheet and with glue applied to the exposed tips on the opposite face of the corrugated board, is to be brought together while continuously advanced through the machine with a second flat sheet to be adhered to said exposed tips, the machine comprising a stationary and substantially rigid hot plate surface over which the second flat sheet with the single-faced board superimposed thereon, is conveyed to cure the glue and produce a double faced board, and means to apply a load on a face of the double faced board which is remote from the hot plate surface to maintain thermal contact between the conveyed double faced board and the stationary hot plate surface;

• characterized in that said hot plate surface comprises a series of individual hot plates aligned in a direction of travel of the double faced board, in that said load applying means includes a series of flexible vessels aligned in the direction of travel of the double faced board and each separately containing a fluid medium and adapted to maintain said double faced board pressed uniformly against the hot plate surface as the double faced board is advanced over the hot plates during conveyance through the machine, thereby to conform to said surface irrespective of any undulation thereof, and wherein the fluid containing vessels rest upon at least one flexible plate which is fixed at one end thereof relative to said fluid containing vessels and which may assume a curvature about an axis extending in the direction of travel of the double faced boards.