Engine-clutch control interlock system

In a power train that includes an engine having an engine speed control means for controlling the speed of the engine in response to an engine speed control signal generated and selectively conducted to the speed controller and a clutch having a clutch control means for engaging and disengaging the clutch in response to a clutch actuator signal, an engine and clutch control interlock system comprising means for monitoring engine speed and producing a speed signal indicative of whether the engine is running at a speed above or below a selected nominal idle speed;

• means for generating and monitoring a clutch control signal and producing a clutch control status signal indicative of whether or not a clutch control signal is being generated;
• means for monitoring the operating status of the clutch and producing a clutch status signal indicative of whether the clutch is engaged or disengaged;
• means responsive to the clutch control status signal and the speed signal for conducting the clutch actuator signal to the clutch control means of a disengaged clutch only when a clutch control signal is generated and the engine is running below the nominal idle speed;
• and means responsive to the clutch status signal for permitting a speed control signal to be conducted to the speed control means only after the clutch is engaged.