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:
May. 30, 1978
Filed:
Nov. 24, 1975
Angel Tonchev Balevski, Sofia, BG;
Ivan Dimov Nikolov, Sofia, BG;
Evgeni Hristov Mateev, Pleven, BG;
Todor Kostadinov Trifonov, Pleven, BG;
Vassil Vladimirov Kojuharov, Pleven, BG;
Abstract
A method of injection molding foamed articles wherein, after the mold is closed and while the mold is held closed, a gas counterpressure is generated within the mold cavity against which a portion of the foamable resin is injected under a pressure which prevents foaming. Thereafter, a shape-forming element adapted to be retracted to be flush with a wall of the mold cavity in the final phase thereof, is advanced to force the nonfoamed material, still against the gas counterpressure, into the remainder of the cavity. After a skin has formed, on the mass within the mold cavity the latter element is retracted to permit foaming, preferably after foaming has been initiated by allowing a portion of the foamable mass to recede into the injection cylinder during the inception of the foaming process.