| 摘要 |
An apparatus to maintain optimum engine speed and cutter wheel speed to maintain peak power output of the engine and peak flywheel effect of the stump cutter wheel. The stump cutter has a rotating cutting wheel powered by an engine, and the cutter is mounted to be moved laterally. The mounting includes a boom and at least a first hydraulic cylinder for urging the boom to move along the path of travel over the surface of a stump. The hydraulic cylinder is activated by a hydraulic circuit which includes a source of pressurized hydraulic fluid. A pressure hydraulic line connects the source of hydraulic fluid to a first port of the hydraulic cylinder and a return line is connected to a second port of the hydraulic cylinder. A valve diverts a portion of flow from the pressure line to the return line or to a sump. The valve is shiftable between at least a first and a second position. In the first position, substantially all hydraulic fluid is passed along the pressure line to the hydraulic cylinder. In the second position, at least a portion of the hydraulic fluid is diverted from the pressure line. A sensor is provided for sensing a speed of the engine. A circuit interconnects the sensor and the valve. The circuit selectively shifts the valve from the first position to the second position when the sensed speed of the engine is less than a predetermined minimum speed.
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