Abstract: A press for rigid foam sheets with continuous adjustment of the spacing between the two press plates (1,3), in particular for sandwich panels with an upper and lower outer layer and, located therebetween, a core of rigid polyurethane foam. The lower press plate (3) is here moved into a preselected position corresponding to the panel thickness to be foamed by means of synchronously rotating threaded lifting spindles (4), assisted by weight-compensating cylinders (5). Short-stroke cylinders (6) are provided between the heads of the threaded lifting spindles (4) and the lower press plate (3). Said short-stroke cylinders have the function of dissipating the moulding force which has arisen due to foaming by moving the press plate (3) a very small stroke downwards. It is also possible, instead of the short-stroke cylinders (6), to install an air cushion system, which has a stroke of approx. 1 mm, between the press plate and the heating plate. This stroke is sufficient to dissipate the foaming pressure.

Abstract: A press for rigid foam sheets with continuous adjustment of the spacing between the two press plates (1, 3), in particular for sandwich panels with an upper and lower outer layer and, located therebetween, a core of rigid polyurethane foam. The lower press plate (3) is here moved into a preselected position corresponding to the panel thickness to be foamed by means of synchronously rotating threaded lifting spindles (4), assisted by weight-compensating cylinders (5). Short-stroke cylinders (6) are provided between the heads of the threaded lifting spindles (4) and the lower press plate (3). Said short-stroke cylinders have the function of dissipating the moulding force which has arisen due to foaming by moving the press plate (3) a very small stroke downwards. It is also possible, instead of the short-stroke cylinders (6), to install an air cushion system, which has a stroke of approx. 1 mm, between the press plate and the heating plate. This stroke is sufficient to dissipate the foaming pressure.