The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 06, 1981
Filed:
Oct. 10, 1980
Michel Vernon, Trilport, FR;
K.R.P. Plastiques, Trilport, FR;
Abstract
An improved process and apparatus for producing rigid cellular materials comprising polyvinyl chloride, wherein the controlled expansion of embryonic blocks obtained by molding, is carried out in a single expansion box closed throughout the whole duration of the expansion treatment, in several stages including pre-heating, pre-expanding and final expansion to the final dimensions of the block, the expansion box containing the block expanded to its final dimensions being then immersed in a bath of cold water for dimensional stabilization. The expansion box comprises at least two plates, with a frame attached to the lower face of each plate, to form, in use, a closed expansion box which is provided with a centering and holding mechanism to maintain the embryonic block in place within the expansion box, a device for opening and closing the expansion box being also provided, as well as a mechanism for transferring a plurality of expansion boxes assembled together from one bath to the other in succession.