| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a control device for a piston concrete pump simply configured to reduce noises and vibration due to the surge pressure of a hydraulic selector valve or the collision of main hydraulic cylinders during the change-over of the valve of the piston concrete pump. <P>SOLUTION: The control device for the piston concrete pump includes proximity sensors 26a, 26b provided on head side pressure chambers 19a, 19b of the main hydraulic cylinders 4a, 4b of the piston concrete pump for detecting that main hydraulic pistons 6a, 6b come close to stroke ends, respectively, and a pressure switch 27 and a depressure valve 28 provided on the discharge side of an oil pump 20 which supplies pressure oil to pressure oil supply and drain lines 8a, 8b. When the discharge pressure of the oil pump 20 is not lower than a set value for the pressure switch 27, if the main hydraulic piston 6a or 6b is detected by the proximity sensor 26a or 26b, the depressure valve 28 is actuated in accordance with a detection signal from the pressure switch 27 and a detection signal from the proximity sensor 26a or 26b to apply depressure to the discharge side of the oil pump 20, thus reducing the speeds of the main hydraulic pistons 6a, 6b. <P>COPYRIGHT: (C)2012,JPO&INPIT |
