HYDRAULIC CONTROLLER FOR DUST COLLECTING VEHICLE

PURPOSE:To increase body locking force by connecting a hydraulic pump with a pair of cylinders so that they may be made a thread take-up lever type to constitute a variable capacity type, and holding a body in a lowering direction when the changing-over switch of a dust processing device is at its neutral position to set pump delivery at zero. CONSTITUTION:While running, a body is at its low position, a detecting switch 16 turns on, and changing-over switch 27 is at its neutral position. When a main switch 26 closes, therefore, oil pressure flows to the rod side of a dumping switch 9, and the body keeps a lowering finish condition to prevent the body from floating. After completion of lowering the dumping cylinder, the pressure of a pump output circuit rises rapidly. With the pressure rising, the contact pressure maintaining control valve 24 of a pump P comes into action, and the discharge rate of the hydraulic pump P is controlled so that it may become zero by the first and second control cylinders 21, 22.