In the production of pressed laminates having a relatively rigid core sheet made of relatively inexpensive material such as woodchips and having at least one high-quality cover sheet which is integrally bonded with the core usually by means of hot pressing it is necessary that the workpiece stack, or sandwich when two cover sheets are used, be loaded into the press without displacement of the various sheets relative to each other It is necessary that the core panel remain within the outlines of the two cover sheets.
Traditionally this workpiece stack or sandwich is gripped along opposite edges and displaced horizontally between the platens of the press. Then both edges are released and the stack is dropped a short distance onto the lower press platen.
Such a system has the disadvantage that a cushion of air forms under the dropping stack which slows its fall and frequently causes the sheets to shift relative to one another. This often results in a spoiled product. The difficulty can be avoided by providing extra-large cover sheets so that even a moderate shifting of the core sheet will not spoil the workpiece as this core sheet will nonetheless remain between the cover sheets. However this latter system is disadvantageous in that it increases the overall cost of the product due to the oversized expensive cover sheets, and requires troublesome trimming operations.
USPTO Backgrounds
USPTO Backgrounds