The function of a manual hydraulic pump is to convert the mechanical energy of a power source (such as an electric motor and an internal combustion engine) into the pressure energy of a liquid.

Operation Principle: The cam is rotated by an electric motor. As the cam pushes the plunger upwards, the sealed volume between the plunger and cylinder decreases, causing the oil to be expelled through a one-way valve to the required location. When the cam rotates to the descending part of the curve, the spring forces the plunger downward, creating a vacuum. Under the influence of atmospheric pressure, oil from the reservoir enters the sealed volume. The cam continuously raises and lowers the plunger, causing the sealed volume to periodically decrease and increase, thereby continuously suctioning and discharging oil.