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Working machine

  • US 20060266029A1
  • Filed: 05/01/2006
  • Published: 11/30/2006
  • Est. Priority Date: 05/24/2005
  • Status: Abandoned Application
First Claim
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1. A working machine comprising:

  • left and right traveling units operating by means of the supply of hydraulic fluid from a hydraulic fluid supply source; and

    a hydraulic pressure supply apparatus, the hydraulic pressure supply apparatus including;

    a first hydraulic pump serving as a hydraulic fluid supply source for supplying hydraulic fluid to the left traveling unit;

    a second hydraulic pump serving as a hydraulic fluid supply source for supplying hydraulic fluid to the right traveling unit;

    a first travel control valve disposed between the left traveling unit and the first hydraulic pump, the first travel control valve having a neutral position for directly leading the hydraulic fluid supplied from the first hydraulic pump to a tank-side flow channel, the first travel control valve leading an amount of the hydraulic fluid from the first hydraulic pump in proportion to an operational amount of the first travel control valve from the neutral position to another position to the left traveling unit;

    a second travel control valve disposed between the right traveling unit and the second hydraulic pump, the second travel control valve having a neutral position for directly leading the hydraulic fluid supplied from the second hydraulic pump to a tank-side flow channel, the second travel control valve leading an amount of the hydraulic fluid from the second hydraulic pump in proportion to an operational amount of the second control valve from the neutral position to another position to the right traveling unit;

    at least one actuator control valve connected to at least one of the tank-side flow channels of the first travel control valve and the second travel control valve, the actuator control valve being switchable between a neutral position and driving position, the neutral position meaning that hydraulic fluid flowing through the tank-side flow channel is directly led to the tank side, the driving position meaning that the hydraulic fluid flowing through the tank-side flow channel is led to a predetermined actuator different from the left and right traveling units;

    a straight-ahead travel control valve being switchable between a block position and merge position, the block position meaning that a first hydraulic supply channel starting from the first hydraulic pump to the first travel control valve is blocked from a second hydraulic supply channel starting from the second hydraulic pump to the second travel control valve, the merge position meaning that the first hydraulic supply channel is connected to the second hydraulic supply channel so as to merge hydraulic fluid ejected from the first hydraulic pump and hydraulic fluid ejected from the second hydraulic pump;

    a third hydraulic pump separately disposed from the first hydraulic pump and the second hydraulic pump;

    a hydraulic feed channel for leading hydraulic fluid ejected from the third hydraulic pump to the predetermined actuator so as to feed the hydraulic fluid to the predetermined actuator;

    a feed switching valve being switchable between a feed position and block position, the feed position meaning that the third hydraulic pump is connected to the hydraulic feed channel, the block position meaning that the third hydraulic pump is disconnected from the hydraulic feed channel; and

    switching control means for switching the straight-ahead travel control valve and the feed switching valve to the block positions when at least one of the first travel control valve and the second travel control valve remains at the neutral position or when all of the actuator control valves remain at the neutral positions and switching the straight-ahead travel control valve to the merge position and the feed switching valve to the feed position when both the first travel control valve and the second travel control valve are operated from the neutral positions by a predetermined operational amount and when at least one of the actuator control valves is operated from the neutral position to the driving position.

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