| 摘要 |
<p>PURPOSE:To strengthen the operating force of attachments and to improve the working efficiency by boosting the relief pressure of arm and boom cylinders rods in case only the head pressure of a bucket cylinder rises to a certain pressure setting of high pressure. CONSTITUTION:Pilot pressure signals entry sections 28 and 30 provided to relief valves 27 and 29 of each rod side of boom and arm cylinders 6 and 7 so as to enable them to give boosting function and a pilot pump 16 are interlocked through a solenoid-valve capable of switching by sensing the head side pressure of a bucket cylinder 8. The pressure setting of the relief valves 27 and 29 is so constituted that it is capable of boosting by the discharge pressure of the pump 16. In case of general soil excavation, the relief pressure of the relief valves 27 and 29 is normal, but the pressure setting of the relief valves 27 and 29 of rods of the cylinders 6 and 7 can be automatically boosted in case there is only a mixture of rocks in the soil or in case only a shovel is rid of mud.</p> |
