| 摘要 |
PURPOSE:To prevent unnecessary up and down swing motion of an operating equipment and improve the security by incorporating a safety circuit which has a make contact point, a break contact point and a plurality of change-over valves, in the travel vibration restraint circuit of a hydraulic means in a wheeled construction machine. CONSTITUTION:When a switch 6 is turned on, for example, electric current flows through a break contact point 3 and an electric wire 38 and to a secondary change-over valve 31. The secondary change-over valve 31 is then changed over to the position F so that a pipe passage 37 communicated with a tank 10 is communicated with a pipe passage 36. Discharge oil in a hydraulic pump 11 is flown via a pipe passage 33 and then into an accumulator 19 and when the pressure in a pipe passage 41 is increased higher than that in the pipe passage 37, a primary change-over valve 30 is changed-over to the position D. Then the discharge oil flows flows into a plurality of hydraulic change-over valves 12 and 13 via the pipe passage 32. And furthermore, when the electric current passing across and switch 6 runs via a limit switch 5 to excite a make contact point 2, an opening and closing valve 17 is changed-over to the position B to realize the vibro-isolation effect. |
