Jack is divided into mechanical jack and hydraulic jack, with different principles. In principle, the hydraulic jack is based on the Pascal principle, that is, the pressure is the same everywhere in the liquid, so in the balanced system, the pressure applied on the smaller piston is relatively small, and the pressure applied on the larger piston is relatively large, so that the liquid can be kept still. So through the transfer of liquid, we can get different pressures on different ends, so that we can achieve a transformation. The hydraulic jack that we often see uses this principle to achieve the transmission of force. The mechanical jack adopts the mechanical principle to pull the handle back and forth, and the claw pulls the ratchet clearance to rotate. The small bevel gear drives the large bevel gear and the lifting screw to rotate, so that the lifting sleeve can be lifted or lowered, and the lifting tension function can be achieved. But not as easy as a hydraulic jack.
The basic equation of static pressure (P = P 0 + ρ GH). When the external pressure P 0 of a liquid in a closed container changes, as long as the liquid remains in its original static state, the pressure at any point in the liquid will change by the same size. That is to say, in a closed container, the pressure applied to the static liquid will be transmitted to each point at the same time with equal value. This is the static pressure transfer principle or Pascal principle. Pascal's law is that in hydrodynamics, because of the fluidity of the liquid, the pressure change of some part of the static fluid in the closed container will transfer the size to all directions without change. Pascal first elaborated this law. The pressure is equal to the applied pressure divided by the area under force. According to Pascal's law, if a certain pressure is applied to one piston in a hydraulic system, the same pressure increment will be produced on the other piston. If the area of the second piston is 10 times that of the first piston, the force acting on the second piston will increase to 10 times that of the first piston, and the pressure on the two pistons will still be equal. This law was first proposed by French mathematician, physicist and philosopher Blaise Pascal. This law has a very important application in production technology. Hydraulic press is an example of Pascal principle. It has many uses, such as hydraulic brake. Pascal also found that the pressure at any point in a stationary fluid is equal in all directions, that is, the pressure at that point is equal in all planes through it. This fact is also known as the Pascal principle.
It can be expressed as: P1 = P2, that is, F1 ÷ S1 = F2 ÷ S2