Dampar and seat suspension mechanism

A damper comprising:

• an outer cylinder;
• a movable inner cylinder having a shorter axial-direction length than an axial-direction length of an inner space of the outer cylinder and movable in the outer cylinder;
• a piston around whose outer peripheral surface a linear member that generates a frictional force with the movable inner cylinder is wound, and which operates in the axial direction in the movable inner cylinder;
• and
• movable inner cylinder cover members provided at axial-direction ends of the movable inner cylinder,
• wherein an orifice is formed in a peripheral wall of the movable inner cylinder, and a viscous liquid is filled in the outer cylinder including the inside of the movable inner cylinder, and
• wherein, when the piston moves relative to the movable inner cylinder, a predetermined damping force is generatable owing to viscous friction generated between the piston and the movable inner cylinder and owing to viscous resistance of the viscous liquid passing through the orifice, whereas when the piston moves in the outer cylinder together with the movable inner cylinder, the predetermined damping force is not generated.