Fluid-driven torsional operators for turning rotary valves and the like

摘要

Fluid-driven torsional operators for turning rotary valves such as ball valves, butterfly valves and the like and for turning similar devices which swing about a pivot axis, said torsional operators including an inflatable fluid-driven torsional actuator having an axially elongated, flexible, hollow, thin-walled elastic shell defining a fluid chamber with a plurality of inextensible flexible strands bonded to this thin-walled shell. These strands extend between the shell ends and are anchored to axially opposed coupling members which are fixed to and in fluid-tight sealing engagement with the opposite ends of the shell. When the torsional actuator is deflated, its flexible shell and the strands bonded thereto are helically twisted or coiled through a predetermined initial angle, and when the chamber within the shell is inflated the shell expands, causing the strands to bow outwardly along arcuate paths and the shell to uncoil, thereby relatively rotating the axially opposed coupling members for turning the valve or other device connected to the coupling members. The predetermined angle through which the shell and strands are initially twisted when the shell is deflated may be selected in accordance with the requirements of the device being turned by the operator embodying the present invention.PPThe opposed coupling members are mounted for relative rotation in a housing which holds these coupling members and establishes the axial distance between them. Further, a coil spring or another actuator, is provided to urge the shell and strands to helically coil into their initial position and thus to reverse the relative rotation of the coupling members, that is, to turn them back toward their starting position when the actuator is deflated.