a hand-operated machine with hydraulic drive that is employed for various technological operations such as tightening threaded joints and pressing in and pressing out parts.
Hydraulic tools are constructed with piston, rotary, screw, and other types of motive power. Those with reciprocating action from piston drives, such as hydraulic nut wrenches, are widely used. Hydraulic tools operate quietly and are dependable in service. Their chief advantage over pneumatic and electrical tools is the possibility of obtaining considerably greater force or torque with tools of the same size. This stems from the fact that the hydraulic drive can operate at pressures ten times higher than the pneumatic drive. However, it is necessary to provide a pump for supplying the working fluid to the hydraulic drive and to use high pressure fittings.
M. L. GEL’FAND