Power-transmission control mechanism for lawn mower

A power-transmission control mechanism for a lawn mower in which power of an internal combustion engine is transmitted to a mowing blade through an electromagnetic clutch, wherein the power-transmission control mechanism comprises:

• an operating switch that is turned on or off by an operator;
• an engine rotational speed detector that detects engine rotational speed of the internal combustion engine;
• and
• an electromagnetic clutch controller that controls operation of the electromagnetic clutch on the basis of an operation signal of the operating switch and the engine rotational speed detected by the engine rotational speed detector;
• and
• wherein the electromagnetic clutch controller is configured to periodically repeats:
• reading the engine rotational speed detected by the engine rotational speed detector, during a predetermined time, when the operating switch is turned on,
• disengaging the electromagnetic clutch when the read engine rotational speed is lower than a lower limit engine rotational speed, which is lower than a specified engine rotational speed by a first predetermined rotational speed,
• engaging the electromagnetic clutch when the read engine rotational speed is equal to or higher than an upper limit engine rotational speed, which is lower than the specified engine rotational speed by second predetermined rotational speed,
• comparing the present engine rotational speed read in present cycle with a previous engine rotational speed read in a previous cycle, when the read engine rotational speed in the present cycle is equal to or higher than the lower limit engine rotational speed and is lower than the upper limit engine rotational speed,
• engaging the electromagnetic clutch when the present engine rotational speed is equal to or higher than the previous engine rotational speed, and
• disengaging the electromagnetic clutch when the present engine rotational speed is lower than the previous engine rotational speed.

A power-transmission control mechanism for a lawn mower in which power of an internal combustion engine is transmitted to a mowing blade through an electromagnetic clutch, wherein the power-transmission control mechanism comprises:

• an operating switch that is turned on or off by an operator;
• a throttle opening detector that detects a throttle opening of a throttle valve provided in an inlet system of the internal combustion engine;
• and
• an electromagnetic clutch controller that controls operation of the electromagnetic clutch on the basis of an operation signal of the operating switch and the throttle opening detected by the throttle opening detector;
• and
• wherein the electromagnetic clutch controller is configured to periodically repeats:
• reading the throttle opening detected by the throttle opening detector, during a predetermined time, when the operating switch is turned on,
• engaging the electromagnetic clutch when the read throttle opening is smaller than an upper limit throttle opening, and
• disengaging the electromagnetic clutch when the read throttle opening is equal to or larger than the upper limit throttle opening.