Expandable lifting devices and valve assemblies for such lifting devices

Abstract

A valve assembly having a rigid mounting and a valve member located in an opening in the mounting wherein an annular part of the mounting around the opening provides a first valve seat on one side thereof and a second valve seat on the other side; wherein the valve member includes a first head joined to a second head by a neck which extends through the aperture; wherein the first head has a resilient flange which resiliently engages the first valve seat to form a first valve and the second head has a resilient flange which resiliently engages the second seat to form a second valve; and wherein the flange of the second head has an actuator formation thereon which is movable to move at least part of this flange off the second seat whereby, in use, to allow fluid under pressure to flow past this flange into the opening for automatically lifting the flange of the first head off the first seat when the fluid pressure in the opening is greater than the fluid pressure at said one side of the mounting.

Dependencies are inferred from the claim text.