Patent ID: 7637039

Claim:
An apparatus for controlling a hydraulic pump for a working machine of a working vehicle having a cylinder arrangement for operating the working machine, a variable displacement hydraulic pump for supplying oil at a specified pressure to said cylinder arrangement, a control valve for controlling a flow rate of oil supplied to predetermined cylinders in said cylinder arrangement and a working machine operating lever, comprising: a bottom pressure detector for detecting a hydraulic pressure in a bottom side of at least one cylinder of said predetermined cylinders in said cylinder arrangement; a displacement control device for controlling a displacement of said variable displacement hydraulic pump so that a load sensing differential pressure that is differential pressure of a load pressure of said predetermined cylinders and a discharge pressure of said variable displacement hydraulic pump becomes constant; and a controller which inputs therein a detection value from said bottom pressure detector, determines that an excavating operation starts when a predetermined time elapses with said detection value at a predetermined value or less and thereafter, said detection value exceeds a predetermined value, and reduces a stroke of said control valve for a maximum stroke of said working machine operating lever to be a smaller predetermined stroke than a maximum stroke.