Patent ID: 6895749

Claim:
A double-acting pressure intensifying cylinder comprising: a first cylinder having a first piston; a second cylinder integrally connected in series to said first cylinder and having a second piston separated from said first piston; an operation chamber provided in an inner portion of said first cylinder and said second cylinder, having a fluid supply port, and having an inner diameter set to be smaller than inner diameters of said first cylinder and said second cylinder; and a check valve provided within said series connected first and second cylinders at a position which is closer to said second cylinder than to the fluid supply port of said operation chamber and which is between said operation chamber and said second piston so as to make it possible for a fluid to flow only in one direction from said operation chamber to said second cylinder, wherein a rod of said first piston cuts off fluid communication between a fluid chamber of said first cylinder and said operation chamber by sliding in said operation chamber, said second piston is stopped at a predetermined position or a given position, and said rod of said first piston is slid continuously and/or intermittently in said operation chamber, a hydraulic fluid is supplied with an amount generally equivalent to a volume of said operation chamber into said second cylinder through said check valve, whereby every time said first piston reciprocally slides once, a pressure-intensified stroke with pressure intensified by the amount generally equivalent to the volume of said operation chamber is obtained in said second piston.