| 摘要 |
A control arrangement (10) for a hydraulic lifting-gear control system on a tractor is proposed which avoids peak starting pressures. The control arrangement (10) has a reversing spool (21) which is controlled by a pilot-control stage (16) and, loaded by a spring (53), assumes a neutral position if there is a lack of feed pressure, in which neutral position it separates a feed chamber (27) from a discharge chamber (26) connected to the tank (34) and connects it to a working line (62, 74, 72) leading to the hydraulic cylinder (12). A pressure-control valve (19) lying in the control circuit (118, 121) of the reversing spool (21) enables the neutral circulation (32, 54) to be rapidly opened in a controlled manner if there is a sudden flow of pressure medium and avoids pressure peaks in the feed chamber (27), while during normal control actions its dampened reversing function is not impaired. <IMAGE>
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