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:
Dec. 05, 2006
Filed:
Feb. 05, 2003
Yoshinori Matsunaga, Tokyo, JP;
Haruhiko Kurino, Tokyo, JP;
Yoshinori Matsunaga, Tokyo, JP;
Haruhiko Kurino, Tokyo, JP;
Kajima Corporation, Tokyo, JP;
Abstract
A hydraulic damper used for reducing shaking of a structure, for example in an earthquake. The hydraulic damper has a cylinder, a piston movable in a reciprocating manner within the cylinder, hydraulic chambers at opposite sides of the piston, and a single on-off control valve. There is a passage for connecting both of the hydraulic chambers and is on-off controlled to change a damping coefficient. A damping coefficient switching-type hydraulic damper is provided between a piston rod and the on-off control valve. A first damping coefficient is attained when the on-off control valve is maintained in a closed state for movement of said piston in one direction, and a second damping coefficient is attained when the on-off control valve is opened. A mechanical drive for the control valve may be a straight gear operatively attached to the piston rod of the cylinder, and a crank mechanism that works with the straight gear to on-off control the control valve.