| 摘要 |
<p>A valve group comprises: a nonnally-closed two-way, two-position delivery valve (7) which places an external source of pressurised gas in communication with a pressurisable chamber (4) of a piston; a nonnally-closed two-way discharge valve (8), which places the pressurisable chamber (4) in communication with a discharge (9); and a total discharge valve (12) which when opened contemporaneously with an opening of the discharge valve, sucks gas from the pressurisable chamber by a venturi effect. The invention can be used in a pneumatic jack of a bellows-type for raising objects, in particular for raising a side of a motor vehicle.</p> |
