Q. How does a hydraulic trolley jack work?

Answer

Oil is pumped between two cylinders in a hydraulic jack trolley to generate force. When the pump plunger is withdrawn, the suction valve is opened, allowing oil to be sucked into the pump. Oil is pumped into the cylinder chamber by an external discharge valve as the plunger is depressed. Because of the pressure of the hydraulic fluid, the main cylinder (also called the ram) extends upwards from the body of the hydraulic jack trolley, providing the necessary lifting force and raising the load. The ram can be retracted and the load decreased thanks to the incorporated pressure release valve.