Patent ID: 7096773

Claim:
A telescopic pneumatic device comprising: an outer cylinder; an inner cylinder disposed in said outer cylinder and being made of a rigid plastic material, said inner cylinder including a cylinder wall defining therein an air chamber, and a valve mounting part which is formed in one piece with said cylinder wall, said valve mounting part having a first cavity; a piston capable of reciprocal motion mounted in said air chamber; a piston rod connected to said piston and extending out of said outer cylinder; a flow passage provided between said cylinder wall and said outer cylinder and having two ends connected respectively to said first cavity and said air chamber; a conduit embedded in said cylinder wall of said inner cylinder and defining said flow passage; and a control valve mounted within said valve mounting part and including a valve section disposed within said first cavity and an operating section connected to said valve section and being operable to control said valve section so as to permit or interrupt fluid communication between said flow passage and said air chamber.