Patent ID: 7887031

Claim:
A stay damper, comprising: a cylinder in which a gas is charged; a piston rod which projects from the cylinder according to a pressure of the gas; a stopper which locks contraction of the piston rod from an elongated position, the stopper displacing between a lock position which locks the contraction of the piston rod and a release position which permits the contraction of the piston rod, according to an operation force applied from outside; a restricting member which holds the stopper in the lock position when the stopper is in the lock position and holds the stopper in the release position when the stopper is in the release position, the stopper displacing only when the operation force is greater than a restriction force of the restriction member; and a cover which covers the piston rod and is connected to a projecting end of the piston rod, the cover being free to swing relative to the piston rod, the stopper being fixed to a tip of the cover, and displacing due to the swinging of the cover, according to the operation force applied from outside, between the lock position and the release position, the cover locking the contraction of the piston rod from the elongated position by interfering with the cylinder when in the lock position; wherein the stopper comprises a holder having an elongated circular shape cross-section which encloses the cylinder, the holder allowing the cylinder to displace only in a direction along a major axis of the elongated circular shape cross-section and the lock position corresponding to an end of the elongated circular shape while the release position corresponds to another end of the elongated circular shape, and a contact face which interferes with the cylinder to prevent contraction of the piston rod.