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:
Apr. 23, 1991
Filed:
Feb. 08, 1989
Shinji Oshima, Ama, JP;
Hidenobu Misawa, Nagoya, JP;
NGK Insulators, Ltd., Aichi, JP;
Abstract
A method for producing a sleeve having a closed end by extruding a forming material from a mouthpiece. A core member is arranged in position in the mouthpiece and has a piston member detachably provided in a tip end of the core member. The piston member has an air communication aperture. On the other hand, an outer die is arranged in the mouthpiece for forming an outer configuration of the closed end. As a result, an annular space is formed by the mouthpiece, core member and outer die. The forming material is then supplied into the annular space and extruded to form the closed end of the sleeve. After the outer die has been removed from the mouthpiece, the piston member is caused to slide relative to the mouthpiece and at the same time the air is blown into an inside of the closed end through the air communication aperture of the piston, while the forming material is further supplied and extruded from the mouthpiece to form the closed end sleeve.