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. 13, 2008
Filed:
Sep. 03, 2004
Takeshi Kamo, Hitachinaka, JP;
Akira Uno, Hitachinaka, JP;
Michio Wakabayashi, Hitachinaka, JP;
Haruhiko Oouchi, Hitachinaka, JP;
Yasuo Sasaki, Hitachinaka, JP;
Takeshi Kamo, Hitachinaka, JP;
Akira Uno, Hitachinaka, JP;
Michio Wakabayashi, Hitachinaka, JP;
Haruhiko Oouchi, Hitachinaka, JP;
Yasuo Sasaki, Hitachinaka, JP;
Hitachi Koki Co., Ltd., Tokyo, JP;
Abstract
A pneumatically operated screw driver ensuring a complete return of a piston to its top dead center. The screw driver has a compressed air return chamber for returning the piston to its top dead center by applying a compressed air in the return chamber to the piston. The piston includes a main piston and an auxiliary piston. The main piston is first reaches its bottom dead center, and then the auxiliary piston reaches its bottom dead center whereupon screw driving is terminated. Before the auxiliary piston reaches its bottom dead center, and after the main piston moves past a predetermined position, a compressed air is introduced into the return chamber. After the main piston reaches the bottom dead center, application of the compressed air pressure in the return chamber to the auxiliary piston is prevented.