Cylinder device

A double housing type machine tool, comprising:

• a double housing balancing device and
• a cylinder device having
• a hollow cylinder tube having a supply flow path formed therein for a working fluid;
• a first piston slidably accommodated in said hollow cylinder tube;
• a first guide bar inserted through said first piston;
• a first piston rod connected to said first piston through said first guide bar and provided with a cylindrical room therein;
• said first piston rod being provided with a first cushion chamber formed between an inner peripheral surface of said piston rod and an end portion of said guide bar;
• a plurality of belleville springs provided between said guide bar and an inside of said first piston;
• a second piston slidably accommodated in said cylindrical room of said first piston rod;
• a second guide bar inserted through said second piston;
• a second piston rod connected to said second piston through said second guide bar;
• said second piston rod being provided with a second cushion chamber formed between an inner peripheral surface of said piston rod and an end portion of said guide bar;
• a plurality of belleville springs provided between said guide bar and an inside of said second piston;
• and
• a means for supplying said working fluid into said cylindrical room of said first piston rod;
• said double housing balancing device for holding a cross beam for up and down motion by said cylinder device, said cross beam bridging a pair of columns standing parallel to each other.