Hydraulic damper is a device that to reduce the resistance of movements, and then depletes the kinetic energy. Hydraulic damper is widely used in automotive and medical equipment; the feature is the resistance changes with running speed. Obviously, it can play a buffer role in connected institutions. The most important feature is that the force of the gas spring changes with velocity of movement. Significantly, when the force point of gas spring movement faster, then the resistances of the spring is increased. In other case, when the force point movements is slow, almost no resistances.