Abstract: This invention relates to means for imparting angular movement to a first member connected to a second member by a hinge in one sense about said hinge pivot axis. The actuator is formed from a flexible substantially inelastic retaining means connected between two anchorage positions on the members and subtending that angle between the two members which is reduced on the first member moving relative to the second member and includes an elongated inflatable conduit of substantially constant surface area which is mounted between the members and the retaining means. The conduit is inflated to press outwards against the retaining means to cause the retaining means to exert a pulling force between the members to impart angular movement to one of said members relative to the other member in this one sense.

Abstract: The present invention relates to a fluid pressure powered actuator for imparting relative angular movement between two members, connected together by a hinge, comprising an elongated inflatable flexible conduit of substantial constant surface area, connected between the two members with its longitudinal axis substantially parallel to the hinge pivot axis and with the two members substantially equispaced around the conduit whereby on inflation, the conduit exerts a pulling force between the two members to impart relative angular movement therebetween.