Safe start system for riding mowers

Claim 1

In combination, a riding type vehicle having traction wheels, an internal combustion engine having a flywheel on its crankshaft shaped to provide a cavity between it and the adjacent wall of the engine, the engine also having an ignition system, transmission means including a manually operable control member movable to an operative position in which it effects a driving connection between the engine and the traction wheels, and safestart means for grounding the ignition system of the engine to keep the engine from starting if it is cranked while said control member is in an operative position, said safe-start means comprising: an ignition system grounding circuit including 1 a first switch operatively connected with said control member to be closed when the control member is in an operative position and open when the control member is not in an operative position, 2 a second switch in series with the first switch so that both switches must be closed to close the grounding circuit, and 3 centrifugally responsive instrumentalities to maintain said second switch closed when the engine is not running and open when the engine is running at above predetermined rpm, said centrifugally responsive instrumentalities being located in the cavity of the flywheel and having an actuator drivingly connected with the crankshaft of the engine to rotate directly therewith and to respond to engine speed, the actuator of said centrifugally responsive instrumentalities having considerable inherent hysteresis so that opening of the switch does not occur until a predetermined high engine speed is reached, but when opened remains open despite a substantial reduction in engine speed.