Patent ID: 6294114
Filing Date: 2001-09-25
Classification: B29C,B29L,B65D

Abstract:
A method for thermoforming a single article from three heat deformable thermoplastic sheets, the method comprising:releasably clamping three thermoplastic sheets to a frame;moving the three thermoplastic sheets on the frame through at least three ovens and heating the three thermoplastic sheets to a heat deformable temperature;moving the three heated sheets successively to a forming station on the frame;supporting in spaced apart overlying relation a first platen and a second platen on the forming station, and causing the platens to travel in opposed directions between open and closed positions;selectively positioning three molds on the first and second platens;selectively slidably moving a second one of the molds and a third one of the molds into and out of position on the second platen;moving the first and second platens in succession between the open and closed position to displace the three molds and to apply pressure to the three heated thermoplastic sheets in order to mold the sheets in a preselected configuration;moving one platen to compress a first one of the molded sheets against a second one of the molded sheets retained by the second platen in order to fuse together the two molded sheets to form a twin sheet molded article; andmoving the platen retaining the twin sheet molded article into compression with the other platen retaining a third one of the molded sheets on the third mold in order to fuse together the twin sheet molded article and the third molded sheet to form a triple sheet molded article.