Jacks are pieces of material handling equipment that uses force multiplication to lift or move heavy loads. The term jacks can refer to a variety of lifting devices that employ leverage and other methods of mechanical advantage to amplify an applied force to provide the ability to transport a load.
Hydraulic jacks are distinguished by their use of an in-compressible liquid, such as hydraulic fluid or jack oil, as the means by which force multiplication is achieved.
It creates pressure by moving oil through two cylinders via a pump plunger. The pump plunger is drawn back, which opens the suction valve and draws oil into the pump chamber. As the plunger is pushed down, the oil is transported through an external discharge valve and into the cylinder chamber. The suction valve then closes, resulting in pressure being built up within the chamber; causing the piston in the chamber to rise and lift your heavy object. This process can be repeated many times, allowing your load to be lifted higher, and higher.