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. 25, 2014
Filed:
Jan. 21, 2010
Tomoyoshi Sakamoto, Ota, JP;
Minoru Ojiro, Gunma, JP;
Hiroki Katagiri, Gunma, JP;
RP Topla Limited, Suita-Shi, JP;
Abstract
A hollow body formed of a thermoplastic resin and having uniform inner diameter and thickness and an excellent inner surface smoothness, and, in particular, a pipe-shaped hollow body having a bent portion is manufactured by injection molding. A method of manufacturing a hollow body includes injecting a molten resininto a mold cavityof a mold, the mold cavityhaving on its one end a pressure portprovided with a floating coreand on its other end an outlet, pressure-injecting a pressurized fluid through the pressure portafter the injection of the molten resin, and moving the floating coretoward the outlet, and, at the same time, extruding the molten resinfrom the outlet In the method, the floating coreis constituted of a columnar portion and a top portion, which is continuously connected to one surface of the columnar portion and has a shape that a cross-sectional area perpendicular to a central axis of the columnar portion gradually decreases from one surface side of the columnar portion. When a diameter of the columnar portion is represented by A, the height of the columnar portion is 0.1 A to 1 A, and the height of the top portion is 0.3 A to 1.6 A.