Development of a Twisting Vacuum Bellows

A vacuum bellows assembly that can follow a twist motion around the axis is designed and developed. The bellows assembly consists of two normal bellows sections and a special bellows section with a corrugation oblique to the axis. A trial model with a total length of 400 mm and an inner diameter of 100 mm is able to absorb the twist up to about ± 22° (44° in total) within a twisting torque of 120 kg · cm while keeping the length constant. The bellows assembly can also follow easily the usual bending, shifting, expanding and contracting motion.