| 摘要 |
<p>The ram of the high speed punching press is driven with a reciprocating movement by an hydraulic piston operated by pressurised medium supplied by an electric motor-driven reciprocating pump. The lower end of a differential piston is chamfered and carries a connecting element, on which a further piston is fitted. Between the chamfered end of the piston and the connecting element, an annular chamber is formed, to which a branch of the feed piping is connected. While the pressure of the medium acts synchronously on the annular chamber the downward movement of the piston closes the connection between the annular chamber and branch.</p> |
