| 摘要 |
A load supporting device to facilitate transport of a load carrying unit along a supporting surface comprises a piston member having a restricted movement in a cylinder member towards and from the supporting surface, a recess open towards the supporting surface, and a spherical supporting member in said recess movable in relation to the piston member to a position partly out from the piston member a channel in the piston provides flow communicating between said recess and the end of the piston member opposite the end from which the spherical member can extend, and an inlet member through the cylinder member is connected to a gas source under pressure to supply gas to the end portion of the piston member adjacent the channel move the piston member and/or the spherical supporting member to a position in which the spherical supporting member contacts the supporting surface, in which position the gas may flow past the spherical supporting member while maintaining an increased pressure in the recess to produce a lifting movement of the load carrying unit from the supporting surface. A valve member is located in the channel to restrict the gas flow to the recess when the spherical supporting member is located in an extended position from the piston member without contacting the supporting surface.
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