Position control apparatus and method for working machine of construction machinery

1. A position control apparatus for a working machine of a construction machine, comprising: a boom driving unit for driving a boom; a bucket driving unit for driving a bucket; a working tool manipulating part for generating a manipulation signal for driving the boom driving unit and the bucket driving unit; a kick-down switch for generating a kick-down signal for lowering a gear stage; and a controller configured to generate output signals as a combined function of the kick-down signal and the manipulation signal such that, if the kick-down signal is generated by the kick-down switch and the manipulation signal is generated by the working tool manipulating part, the controller outputs a control signal to the boom driving unit and the bucket driving unit to move the boom and the bucket to a preset position, and such that if the kick-down signal is generated by the kick-down switch and the manipulation signal is not generated by the working tool manipulating part, the controller outputs the kick-down signal to a transmission control unit to lower a gear stage.

2. The position control apparatus of claim 1 , wherein the manipulation signal of the working tool manipulating part for moving the boom and the bucket to the preset position is a boom-down signal.

3. The position control apparatus of claim 2 , further comprising: a boom posture detecting sensor for detecting a posture of the boom; and a bucket posture detecting sensor for detecting a posture of the bucket, wherein if the kick-down signal and the boom-down signal are input, the controller drives the boom driving unit and the bucket driving unit until the signals output by the boom posture detecting sensor and the bucket posture detecting sensor, respectively are the same as signals for the postures of the boom and the bucket corresponding to the preset position.

4. The position control apparatus of claim 2 , wherein the working tool manipulating part includes: a boom manipulating part for generating a manipulation signal for driving the boom; and a bucket manipulating part for generating a manipulation signal for driving the bucket, wherein the kick-down switch is installed in the boom manipulating part, and the preset position is a position of the bucket where a bottom surface of the bucket is parallel to the ground surface and a position of the boom where the bottom surface of the bucket is close to the ground surface.

5. A position control apparatus for a working machine of construction machinery, comprising: a boom driving unit for driving a boom; a bucket driving unit for driving a bucket; a working tool manipulating part for generating a manipulation signal for driving the boom driving unit and the bucket driving unit; a manipulation unit for changing the boom and the bucket to a preset posture; and a controller configured to output a control signal to the boom driving unit and the bucket driving unit such that, if a manipulation signal of the manipulation unit is input, the bucket is automatically moved to a position close to the ground surface in parallel to the ground surface by lowering the boom and changing a posture of the bucket; wherein the working tool manipulating part includes a boom manipulating part for generating the manipulation signal for driving the boom, and when the manipulation signal of the manipulation unit is input and a boom-down signal is input by the boom manipulating part, the controller automatically drives the boom and the bucket, and wherein when the manipulation unit is manipulated while the boom-down signal is not input, the controller is a kick-down switch for outputting a transmission adjusting signal to a transmission control unit and is installed on an upper surface of the boom manipulating part to be manipulated together with the boom manipulating part.