HYDRAULIC CYLINDER APPARATUS

PROBLEM TO BE SOLVED: To provide a technique concerning a hydraulic cylinder apparatus which reinforces a starting force on a drawing side for working on a load such as a metallic mold, by a restoring force of an elastic body like a belleville spring. SOLUTION: An elastic body 2 like a belleville spring 21 is installed on a cylinder tube 13 on a rod cover 15 side with a piston rod 12 as an axial center. A pressurizing part 23 for contracting the elastic body 2 on the terminating end of the upstroke of a piston 11, which works a force on the pushing side on the load 4 by operating a hydraulic force on a hydraulic chamber 16a on the head side, is installed on the piston rod 12. Then, the restoring force of the elastic body 2 is generated on the starting end of the downstroke of the piston 11, which works a force on the drawing side on the load 4 by operating the hydraulic force on the hydraulic chamber 16b on the rod side. As a result, the force of the starting time of the drawing side for working on the load 4 is increased, which reduces the capacity of the hydraulic cylinder apparatus 1 for driving the load 4 such as a metallic mold. COPYRIGHT: (C)2011,JPO&INPIT