Chair face lifting chair lift is mainly by the lowerpart of the lifting device, the current main lifting device is divided intothree categories: hydraulic, mechanical and pneumatic. Pneumatic lifting chairis the most common chair lift, pressure lifting chair in a pressure rod,pneumatic rod is a kind of gas and liquid as working medium, can support,buffer, brake, height adjustment and Angle adjustment function such as elasticelement, its basic principle is filled with high pressure nitrogen, due to thepiston with internal hole, the gas pressure is equal on both ends of thepiston, the piston on both sides of the cross-sectional area is different, withpiston rod and the other end without end, under the influence of gas pressure,produce to the small area on one side of the pressure, the pressure elasticrods, sat up to press the elevator shaft, lift shaft will gradually decline,uniform speed, can hit bottom. Don't give lift shaft force, lift shaft back tothe highest point. Concentration of normal manufacturer adopt nitrogen filling,generally over 99%, the pressure around one or two atmospheres.