| 摘要 |
<p>The invention concerns a method for the automatic lightening of a machine working unit (U) by means of a hydraulic jack (57) associated with a hydropneumatic accumulator (67). The method is characterised in that it consists in: using a second hydraulic jack (58) whose piston (53) capable of moving to a predetermined position (PP) in the cylinder (C2) and disengaged from the rod (46) of the first hydraulic jack (57),acts directly or indirectly on the latter by means of the oil (O) contained in the first hydraulic jack (57); lifting and lowering the working unit (U) using the second hydraulic jack (58); in lifting the working unit (U) the volume of oil is increased or decreased in the first hydraulic jack (57) such that the working unit (U) is always at a predetermined height (HP) at the end of the lifting stroke.</p> |
