Safety interlock for an engine ignition system

Claim 1

In an apparatus including an engine having a capacitor-discharge engine ignition system having a timing cycle including a first component consisting of a charge storage capacitor, means connected to charge said capacitor through a charge path, a second component consisting of a unidirectional current rectifier means connected in said charge path in series with said capacitor to block the discharge of said capacitor through said charge path in the absence of an unsafe condition, and a third component consisting of a discharge triggering means connected to said capacitor through a discharge path and having a control terminal connected to receive a discharge control signal at a preselected time in the timing cycle, said triggering means discharging said capacitor through the discharge path when the discharge control signal is received by said control terminal, spark producing means connected in said discharge path such that said capacitor discharges therethrough and produces an ignition spark, all of said components being inherently essential to the proper operation of said ignition system, the improvement being a safety interlock system for preventing engine ignition upon the occurrence of an unsafe condition comprising: safety switch means movable between open and closed conditions and connected to one of said first, second and third components for disabling said one component to function in said ignition system by electrically isolating said one component from said ignition system when said switch means is one of said open and closed conditions, said switch means and said one component being disposed within an integrally encapsulated structure located remote from the other said components, said switch means being in one of said open and closed conditions on the occurrence of a preselected unsafe condition of said apparatus to electrically isolate the inherently essential component from the ignition system and render the ignition system inoperative.