Claims
- 1. In an internal combustion engine powered implement having an engine with a piston disposed in a cylinder, a crankshaft, a flywheel secured to the crankshaft, and a sparking device for igniting fuel in the cylinder, a safety device comprising:
- an ignition circuit operable to produce a spark in the sparking device to combust the fuel, said ignition circuit having means for generating a normally timed sparking voltage to normally combust the fuel, and means for generating an advanced timed sparking voltage to prematurely combust the fuel;
- a switch device for decoupling one of said generating means from said ignition circuit and connecting the other of said generating means in said ignition circuit; and
- a deadman mechanism operable to actuate said switch device, said deadman mechanism being operator actuable into a first position wherein said switch device decouples said means for generating an advanced timed sparking voltage from said ignition circuit whereby said engine may normally run, said deadman mechanism normally biased into a second position when released by the operator wherein said switch device decouples said means for generating a normally timed sparking voltage from said ignition circuit and connects said means for generating an advanced sparking voltage to cause the engine to rapidly slow and stop under influence of the prematurely combusted fuel.
- 2. The safety device of claim 1, wherein said means for generating a normally timed sparking voltage is a first breaker switch and a first rotating cam, said first rotating cam open circuiting said first breaker switch to generate said normally timed sparking voltage, and said means for generating an advanced timed sparking voltage is a second breaker switch and a second rotating cam rotating in advanced phase relative to said first cam, said second rotating cam open circuiting said second breaker switch to generate said advanced timed spar said first cam open circuits said first breaker switch.
- 3. The safety device of claim 2, wherein said switch device alternatively connects one of said first breaker and said second breaker switch in said ignition circuit an disconnects the other of said first breaker switch and said second breaker switch when actuated by the deadman mechanism.
- 4. The safety device of claim 1, wherein said ignition circuit further comprises a magnet disposed on the flywheel so as to rotate therewith, said magnet producing a magnetic flux gradient about the flywheel;
- said means for generating a normally timed sparking voltage is a first coil disposed about the periphery of the flywheel and responsive to said magnetic flux, said means for generating an advanced sparking voltage is a second coil disposed about the periphery of the flywheel and responsive to said magnetic flux, said second coil being circumferentially spaced from said first coil such that said magnet passes said second coil before said first coil.
- 5. The safety device of claim 4, wherein said first coil is disposed about the periphery of the flywheel to generate a sparking voltage when the piston is approximately 0.degree. BTDC, and said second coil is disposed about the periphery of the flywheel to generate an advance sparking voltage when the piston is approximately 110.degree. BTDC.
- 6. The safety device of claim 4, wherein said switch device alternatively connects one of said first coil and said second coil in said ignition circuit and disconnects the other of said first coil and said second coil when actuated by the deadman mechanism.
- 7. The safety device of claim 1, including a mechanical blade brake that is actuated when said deadman mechanism is released.
- 8. In an internal combustion engine powered implement having an engine with a piston disposed in a cylinder, a crankshaft, a flywheel secured to the crankshaft, a magnet disposed on the flywheel so as to rotate therewith, the magnet producing a magnetic flux gradient about the flywheel, and a sparking device for igniting fuel in the cylinder, a safety device comprising:
- an ignition circuit operable to produce a spark in the sparking device to combust the fuel, said ignition circuit including a first coil disposed about the periphery of the flywheel and responsive to the magnetic flux generated by the magnet, said first coil for generating a normally timed sparking voltage to normally combust the fuel, and a second coil disposed about the periphery of the flywheel and responsive to the magnetic flux generated by the magnet, said second coil for generating an advanced timed sparking voltage to prematurely combust the fuel;
- a switch device for decoupling one of said coils from said ignition circuit and connecting the other of said coils in said ignition circuit; and
- a deadman mechanism operable to actuate said switch device, said deadman mechanism being operator actuable into a first position wherein said switch device decouples said second coil from said ignition circuit whereby said engine may normally run, said deadman mechanism normally biased into a second position when released by the operator wherein said switch device decouples said first coil from said ignition circuit and connects said second coil to cause the engine to rapidly slow and stop under influence of the prematurely combusted fuel.
- 9. The safety device of claim 8, wherein said first coil is disposed about the periphery of the flywheel so as to generate a sparking voltage upon passage of said magnet when the piston is approximately 0.degree. BTDC, and said second coil is disposed about the periphery of the flywheel and circumferentially spaced from said first coil so as to generate an advanced sparking voltage upon passage of said magnet when the piston is approximately 110. BTDC.
- 10. The safety device of claim 8, including a mechanical blade brake that is actuated when said deadman mechanism is released.
- 11. In a lawnmower having wheels and a handle gripped by an operator, the lawnmower powered by a single cylinder internal combustion engine having a piston disposed in the cylinder, a crankshaft, a flywheel disposed on one end of the crankshaft, a blade disposed on another end of the crankshaft, a magnet disposed on the flywheel, the magnet producing a magnetic flux gradient from the flywheel, and a spark plug for igniting fuel in the cylinder, a safety device for stopping the engine, the safety device comprising:
- a solid state ignition circuit for producing a spark in the spark plug to combust the fuel, said ignition circuit including a first coil disposed about the periphery of the flywheel and responsive to the magnetic flux as said magnet passe thereby to produce a normally timed sparking voltage for said ignition circuit, and a second coil disposed about the periphery of the flywheel angularly spaced from said first coil and responsive to the magnetic flux as said magnet passes thereby to produce an advanced timed sparking voltage for said ignition circuit to prematurely combust the fuel;
- a switch device for decoupling one of said coils from said ignition circuit and connecting the other one of said coils in said ignition circuit; and
- a deadman lever pivotally attached to the handle so as to be gripped by an operator during operation of the lawnmower and operable to actuate said switch device, said deadman lever being operator biased during gripping of the handle into first position wherein said switch device decouples with second coil from said ignition circuit whereby the engine may normally run, said deadman lever normally biased into a second position when released by the operator wherein said switch device decouples said first coil from said ignition circuit and connects said second coil to cause the engine to rapidly slow and stop itself and the blade under influence of the prematurely combusted fuel.
- 12. The safety device of claim 11, wherein said first coil is disposed about the periphery of the flywheel so as to generate a sparking voltage upon passage of said magnet when the piston is approximately 0.degree. BTDC, and said second coil is disposed about the periphery of the flywheel and circumferentially spaced from said first coil so as to generate an advanced sparking voltage upon passage of said magnet when the piston is approximately 110.degree. BTDC.
- 13. The safety device of claim 11, including a mechanical blade brake that is actuated when the deadman lever is released.
- 14. The safety device of claim 11, wherein said lawnmower is a walk behind lawnmower.
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation-in-part of co-pending application Ser. No. 07/878,175 filed May 4, 1992 now abandoned entitled "IGNITION BRAKE FOR INTERNAL COMBUSTION ENGINE" by the present inventor.
US Referenced Citations (13)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
878175 |
May 1992 |
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