| 摘要 |
<p>The described drive unit (10) comprises a cam (11) acting on at least one hydraulic drive plunger (16, 17) hydraulically connected to at least one thrust plunger (18, 19) for a traction carriage (20, 21) to be moved along its stroke. Advantageously, the thrust plunger (18, 19) is a double-acting plunger one side of which is connected to said hydraulic drive plunger (16, 17) and the other side is connected to an expansion element (41, 42) storing kinetic energy in the form of pressure when the carriage is pushed in its forward stroke and giving the kinetic energy back for pushing the carriage (20, 21) in its backward stroke. In particular, the drive plungers (16, 17) are two in number and are disposed in phase opposition to be controlled by the cam (11) for alternately pushing two carriages (20, 21) aligned with each other along a forward stroke.</p> |
