The trailer jack
is mainly used in factories, mines, transportation and other departments as vehicle repair and other lifting and support work. The structure is light, firm, flexible and reliable, and can be carried and operated by one person.
In principle, the most basic principle of hydraulic transmission is Pascal's law, that is, the pressure everywhere in the liquid is consistent. The common hydraulic jack uses this principle to achieve force transmission.
The screw jack
pulls the handle back and forth, pulls out the claw, that is, it pushes the ratchet clearance to rotate, and the small bevel gear drives the large bevel gear to rotate the lifting screw, so that the lifting sleeve can be lifted or lowered to achieve the function of lifting tension, but it is not as simple as the hydraulic jack.