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:
Mar. 30, 2004
Filed:
Sep. 05, 2001
Carl W. Van Gilst, Goshen, IN (US);
Rotational Molding Technologies, Inc., New Paris, IN (US);
Abstract
A rotomolded plastic wall and ladder structure ( or )), which may be an article such as a window well ( ) or a manhole ( or ), includes a thermoplastic wall ( ), a ladder ( ) whose rungs ( ) each include an elongated metallic core ( ) and a thermoplastic sleeve ( ). Mold apparatus ( ) includes a thermoplastic rotomold ( ), an elongated hollow metallic core ( ) having a heating passage ( ) therein, and means for flowing hot air through the heating passage ( ). The method includes disposing the hollow metallic core in a mold, placing a quantity of a thermoplastic inside a mold, heating the mold, rotating the heated mold, flowing heated air through the hollow metallic core, and bonding a layer of the thermoplastic onto the hollow metallic core.