Hydraulic locking device

A hydraulic locking device, comprising:

• a rod;
• a sleeve body fitting outside said rod;
• said sleeve body having an elastically deformable thinned tube part;
• a case member supporting said sleeve body;
• an outer periphery hydraulic pressure chamber on an outer periphery of said thinned tube part of said sleeve body;
• a hydraulic intensifier inside said case member, having a discharge part continuous with said outer periphery hydraulic pressure chamber;
• said hydraulic intensifier having an annular piston member fitted outside said sleeve body;
• an input port for supplying input hydraulic pressure from an exterior of said hydraulic locking device to an input oil chamber of said hydraulic intensifier;
• oil being sealed in said outer periphery hydraulic pressure chamber and said discharge part;
• a spring housing hole, said spring housing hole having one end open, and being formed proximal a shaft core of said rod;
• a spring bearing member partially slidably inserted inside said spring housing hole and affixed to a bottom wall of said case member;
• a compression spring attached to said spring housing hole and stopped by said spring bearing member at one end;
• said rod is elastically impelled towards a spring housing hole opposite end by said compression spring;
• and
• said rod being locked by driving said hydraulic intensifier with said input hydraulic pressure, whereby a hydraulic pressure that is higher than said input hydraulic pressure is generated to elastically deform said thinned tube part of said sleeve body to a smaller diameter frictionally locking said rod.