Pneumatic or hydraulic jack - has overlapped or interleaved flexible sheets forming envelope

摘要

The jack has a multi-layer envelope impermeable to air or liquid under pressure and textile-reinforced, its volume varying with internal pressure supplied via a union. It has two or more sheets, armoured if necessary, each comprising one or more layers of flexible and very strong material, in one piece or joined together along one or more edges by overlapping or interleaving of the layers. If required, one or more reinforcing strips can be provided, covering them or interleaved with their layers. The sheets can be rectangular or round, and one can include a layer of slightly elastic and impregnable cloth with wire woven into it.