摘要 |
A piston rod is formed in a diameter smaller than an inner diameter of a hollow cylinder. The piston rod is inserted in the cylinder so as to be relatively movable in an axial direction of the cylinder. A locking mechanism comprises a first surface provided on the inner surface of the cylinder, a plurality of second surfaces arranged in an axial direction of the piston rod and parallel to one another, and a locking member. The first surface is so inclined that the inside diameter of the cylinder gradually increases toward one end of the cylinder. Each second surface is so inclined that the diameter of the piston rod gradually increases to the one end of the piston rod. The locking member is held between the first surface and any one of the second surfaces to lock relative movement of the piston rod with respect to the cylinder.
|