Rotary jack with blade mounted on shaft - has ball valve opposing pressure reduction on blade joint internal faces

摘要

The rotary jack has a cylindrical housing whose sides and ends form a cylindrical chamber containing a coaxial rotary shaft. A blade fixed in the housing has a seal bearing against the shaft, while a further blade (9) fixed to the shaft has a seal acting against the chamber walls. A medium under pressure is delivered to one or the other of the fixed blade faces. The moving blade (9) has a radial slot (13) accommodating a movable U-section sealing joint (14), whose outside faces bear against the internal surface of the chamber. The internal faces of this joint are connected to each of the side faces of the moving blade by a passage (20) containing a ball valve (19) opposing any reduction in pressure against these faces.