Hydraulic Control Device of Wheeled Industrial Vehicle

A hydraulic control system for a wheeled working vehicle provided with an engine, a starter for starting up the engine, a hydraulic pump drivable by the engine, an accumulator for storing pressure oil therein by being fed with hydraulic oil delivered from the hydraulic pump, a brake system for applying braking to wheels by the pressure oil stored in the accumulator, and a brake valve for controlling the pressure oil to be fed to the brake system, wherein:

• the hydraulic control system is provided with:
• a first accumulator connected, as the accumulator, to a first line connecting the hydraulic pump and the brake valve to each other,
• a second accumulator connected, as the accumulator, to a second line branching from the first line at a point between the hydraulic pump and the first accumulator,
• an operation detection device for detecting whether or not the starter is in an operation state,
• a rotational frequency detection device for detecting a rotational frequency of the engine,
• an on/off valve arranged in the second line and switchable in valve position to an open position, where the first line and the second accumulator are communicated to each other, or a closed position, where the first line and the second accumulator are cut off from each other, and
• a valve control device for controlling the on/off valve based on the operation state of the starter as detected by the operation detection device and the rotational frequency of the engine as detected by the rotational frequency detection device;
• and
• upon detection of the operation state of the starter by the operation detection device, the valve control device controls the valve position of the on/off valve at the closed position until the rotational frequency of the engine as detected by the rotational frequency detection device reaches a preset rotational frequency set beforehand, but controls the valve position of the on/off valve at the open position after the rotational frequency of the engine has reached the preset rotational frequency.