| 摘要 |
PURPOSE:To prevent occurrence of an engine stall in a working area having a high running resistance by changing the displacement transmission ratio of a link mechanism linking between a potentiometer and an actuator so that a high speed position of an actuator which is lower than the maximum speed position thereof coincides with the maximum position of the potentiometer. CONSTITUTION:In an working area having a running resistance, the displacement transmission ratio of a link mechanism 17 between a potentiometer and an actuator 9 is changed. In this phase, when a setting unit is manipulated toward the high speed side, the actuator 8 is also operated toward the high speed side, following up the manipulation of the setting unit so that a feed-back signal from a potentiometer 9 for detecting the operating position of the actuator 8 coincides with a set signal from the setting unit. When the setting unit is manipulated to the maximum speed position, although a feed-back signal from the potentiometer coincides with or corresponds to the maximum speed position, the actuator 8 is set at a high speed position which is lower than the maximum speed position, thereby it is possible to prevent occurrence of a maximum speed position. |
