Hydraulic jack refers to the use of plunger or hydraulic cylinder as a rigid lifting of the jack. It has the characteristics of compact structure, smooth work, large jacking force and self-locking. The hydraulic Jack's bracing ability is strong.
Hydraulic jacks are divided into: General hydraulic jacks, special hydraulic jacks.
The general hydraulic jack is suitable for lifting the lifting height is not big. It is composed of oil chamber, pump, reservoir cavity, piston, crank, valve and other main parts. Work, as long as the reciprocating wrench, so that the manual oil pump continuously to the cylinder pressure oil, because the oil cylinder pressure in the constant increase, forcing the piston and the heavy weights on the piston together upward movement. Open the return valve, the high-pressure oil in the tank will flow back to the oil storage cavity, so the weight and the Pistons also fall together.
Special-Purpose hydraulic jack is a special tensioning machine, in the production of prestressed concrete members, the Prestressing force to exert tension. The special hydraulic jack is double action type.