Hydraulic nut is specially suitable to narrow space and tightness of vibration mechanics of heavy load. It can simultaneously assemble several bolts of same size. No torque design is adopted to avoid the factors of that friction and bolt-torqued influence pretension force of bolts. The clamped bolts undergo pure tensile force. Preload may be given precisely. Its accuracy is as high as �3%.There is a stroke indicator which is allowed to observe, measure and control the stroke of piston in the course of operation.

Hydraulic nut is specially suitable to narrow space and tightness of vibration mechanics of heavy load. It can simultaneously assemble several bolts of same size. No torque design is adopted to avoid the factors of that friction and bolt-torqued influence pretension force of bolts. The clamped bolts undergo pure tensile force. Preload may be given precisely. Its accuracy is as high as �3%.There is a stroke indicator which is allowed to observe, measure and control the stroke of piston in the course of operation.