Device for preventing an internal combustion engine from revolving at more than the predetermined speed

Claim 1

A device for preventing an internal combustion engine from revolving at more than the predetermined speed in combination with an ignition system for the engine comprising a power source, an ignition coil including a primary coil portion and a secondary coil portion with said primary coil portion supplied with a primary current from said power source and switching means to interrupt the primary current through said primary coil portion of said ignition coil, said device including a semi-conductor controlled switching element connected in parallel to said primary coil portion of said ignition coil; and a control circuit comprising a transistor to control triggering of said semiconductor switching element, an r.p.m. detector to control said transistor in response to the r.p.m. of said engine, a series connection of a first diode, a first resistor, a capacitor and a second diode with said series connection connected in parallel to said primary coil portion and wherein said transistor has the emitter grounded, the base connected to the output of said r.p.m. detector and the collector connected through a second resistor to said first diode at the end adjacent to said power source, said transistor at the collector further connected to the point between said capacitor and said second diode and said semiconductor controlled switching element having the gate connected to the point between said first resistor and said capacitor, said control circuit connected to control said semiconductor controlled switching element so that it is non-conductive upon said engine revolving at less than the predetermined r.p.m. and so that said semiconductor controlled switching element is conductive upon said engine revolving at more than the predetermined r.p.m. whereby when said semiconductor controlled switching element is non-conductive it allows said ignition coil to induce a high voltage across said secondary coil portion for normal operation of the ignition system and when said semiconductor controlled switching element is conductive said semiconductor controlled switching element shorts a primary voltage across said ignition coil established upon opening of said switching means for non-operation of the ignition system.

Claim 2

A device for preventing an internal combustion engine from revolving at more than the predetermined speed in combination with an ignition system for the engine comprising a power source, an ignition coil including a primary coil portion and a secondary coil portion with said primary coil portion supplied with a primary current from said power source and switching means to interrupt the primary current through said primary coil portion of said ignition coil, said device including a semi-conductor controlled switching element connected in parallel to said primary coil portion of said ignition coil; and a control circuit comprising a transistor to control triggering of said semiconductor switching element, an r.p.m. detector to control said transistor in response to the r.p.m. of said engine, a series connection of a first diode, a first resistor, a capacitor and a second diode with said series connection connected in parallel to said primary coil portion and wherein said transistor has the emitter grounded, the base connected to the output of said r.p.m. detector and the collector connected through a second resistor to said first diode at the end adjacent to said power source, said transistor at the collector further connected to the point between said capacitor and said second diode and said semiconductor controlled switching element having the gate connected to the point between said first resistor and said capacitor, said control circuit connected to control said semiconductor controlled switching element so that it is non-conductive upon said engine revolving at less than the predetermined r.p.m. and so that said semiconductor controlled switching element is conductive upon said engine revolving at more than the predetermined r.p.m. whereby when said semiconductor controlled switching element is non-conductive it allows said ignition coil to induce a high voltage across said secondary coil portion for normal operation of the ignition system and when said semiconductor controlled switching element is conductive said semiconductor controlled switching element shorts a primary voltage across said ignition coil established upon opening of said switching means for non-operation of the ignition system.