The hydraulic principle of pallet jacks

The large cylinder 9 and the large piston 8 constitute a lift cylinder. Lever handle 1, small cylinder 2, small piston 3, one-way valve 4 and 7 form a manual hydraulic pump. Such as lift the handle so that the small piston to move up the small piston lower end of the oil chamber volume increases, the formation of local vacuum, then check valve 4 open, through the suction pipe 5 from the oil tank 12 oil; forced down the handle, the small piston down, The pressure of the lower piston chamber is raised, the check valve 4 is closed, the check valve 7 is opened, and the oil of the lower chamber is input into the lower chamber of the lift cylinder 9 through the pipe 6, forcing the large piston 8 to move upwards. When the handle sucks oil again, the check valve 7 closes automatically, so that the oil can not flow back, thus ensuring that the weight does not fall on its own. Constantly pull back and forth handle, you can continue to push the oil into the lifting cylinder under the cavity, so that heavy objects gradually rise. If the shut-off valve 11 is opened and the fluid in the lower chamber of the lift cylinder passes through the pipe 10 and the shut-off valve 11 flows back to the tank, the weight is moved downward. This is the hydraulic principle of a pallet truck.

Simply it is just like the Inflator,but take place air with oil

The hydraulic principle of pallet jacks