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:
Nov. 28, 1989
Filed:
Dec. 24, 1987
Kent H French, Newport News, VA (US);
Rampart Packaging Inc., Houston, TX (US);
Abstract
This invention relates to a method and apparatus for making cupped articles from thermoplastic sheet or billets wherein the articles are formed with a bellows bottom which will displace inwardly when the internal pressure within the cup decreases. The invention specifically relates to an improvement upon the forming process which involves clamping a heated sheet or billet of a thermoplastic material in the solid phase state between a forming plug and a hollow mold having an end opening, moving the forming plug into the opening to carry the sheet into the mold, and introducing pressure fluid into the stressed portion of the sheet to form the article by making the sheet conformed to the shape of the hollow mold. The closed end of the hollow mold is improved by forming it with a flat central portion which has a tapered portion extending outwardly therefrom. The tapered portion tapers in the direction of the open end of the mold and ends in a ridge which extends away from the open end and vertically beyond the flat central portion. A second ridge extends beyond the first. The forming plug is improved in that it has inwardly tapering sides which terminate in a curved portion which itself terminates at a plug tip. The radius of the curved portion is greater than the radius of the plug tip. Preferably, the plug tip is flattened but still rounded such that its height is less than its radius. Also, most preferably, the taper of the forming plug sides is from 9.degree. to 11.degree. from vertical.