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:
Sep. 20, 1983
Filed:
Dec. 18, 1980
Ichiro Nakamura, Katsuta, JP;
Mitsuaki Takenoshita, Katsuta, JP;
Ken Ichiryu, Mito, JP;
Yoshimichi Akasaka, Hitachi, JP;
Haruo Watanabe, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A hydraulic operating apparatus including an actuating cylinder having a piston arranged therein and moved by a fluid under high pressure further includes a control valve having only one metallic seal whether the piston is at its upper or lower positions. The control valve is operative to apply the fluid under high pressure to a pressure receiving surface of the piston on the opposite side of a piston rod to move the piston in a direction in which the piston rod extends from the piston and to discharge the fluid existent on the opposite side of the piston rod from the actuating cylinder to move the piston in a direction opposite the direction in which the piston rod extends from the piston. The hydraulic operating apparatus further includes a seal for dividing the pressure receiving surface of the piston on the opposite side of the piston rod into first and second pressure receiving surface sections, the first pressure receiving surface section having an effective pressure receiving area smaller than that of a pressure receiving surface of the piston on the side of the piston rod.