Patent ID: 7216580

Claim:
A multistage stroke cylinder apparatus comprising: a main cylinder including a main piston housed for sliding in a cylinder tube and driven by fluid pressure supplied to pressure chambers on opposite sides of said main piston and a main rod connected to said main piston, a head cover and a rod cover being mounted to opposite ends of said cylinder tube; an intermediate stop position setting mechanism for setting an intermediate stop position of said main piston; and a return position setting mechanism for setting a return position of said main piston, wherein said intermediate stop position setting mechanism includes a stop position setting piston disposed for sliding between said main piston in said cylinder tube and said head cover to define said intermediate stop position of said main piston by coming in contact with said main piston, an auxiliary rod connected to said stop position setting piston and having a tip end passing through said head cover and extending outside, a stopper fitted with said tip end of said auxiliary rod to stop said stop position setting piston in a necessary position by coming in contact with a contact portion of said head cover, and a changing mechanism for changing a stop position of said stop position setting piston when said stopper comes in contact with the contact portion, wherein said changing mechanism has a mechanism for changing a mounting position of said stopper on said auxiliary rod, said stopper has a plurality of stepped portions formed on opposite sides of an inner hole of said stopper and having different depths and a stepped portion formed on an outer periphery of said auxiliary rod and is formed to be able to change said mounting position of said stopper on said auxiliary rod by changing an orientation of said stopper to selectively bring any of said stepped portions into contact with said stepped portion of said auxiliary rod, and said return position setting mechanism includes a return position setting piston provided for sliding in said head cover and a position setting rod connected to said return position setting piston and having a tip end projecting so as to directly act on and behind said stop position setting piston.