US3961618A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Small engine ignition system with spark advance
Assignee: STANDARD MAGNETO SALES Co Inc
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Filing: 1974-11-25
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Granted: 1976-06-08
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Expires: 1994-11-25
Abstract
Abstract An ignition system for a small internal combustion engine is energized by an alternator which is rotatably driven in association with the engine, and ignition pulses are supplied to the engine in timed relation with the movement of a plurality of different pistons in response to trigger signals generated by a trigger mechanism. The ignition pulses are produced by a capacitive discharge ignition circuit having a pulse transformer associated with each of the different pistons, and the energization of each pulse transformer is controlled by a corresponding switch which is actuated by a trigger signal generated in an associated trigger coil by the rotational movement of a magnetic trigger rotor driven in association with the engine. The trigger rotor carries magnetic means in association with an outer member of magnetically conductive material and having an eccentric configuration defining an intervening air gap with the trigger coil which varies with the movement of the trigger rotor. A radial slot is formed in the periphery of the outer member at a location furthest from the axis of rotation, and the magnetic means provide magnetic poles of opposite polarity on opposite sides of the radial slot to establish a magnetic field with flux reversal for generating a trigger signal of maximum magnitude at low engine speeds. To advance the timing of the ignition pulses a notch is formed in the periphery of the trigger rotor adjacent the radial slot to provide a variation in the flux density for generating a trigger signal which becomes sufficient to actuate the switches upon acceleration of the engine to a predetermined speed.
Inventors
- 👤 Thomas Edwin Swift
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:16
CPC Classifications
F; F02; F02P; F02P7/00; F02P7/06; F02P7/067; F02P7/0675; F02P1/00; F02P1/02; F02P1/08; F02P1/086; F02P11/00; F02P11/02; F02P3/00; F02P3/06; F02P3/08; F02P3/09; F02P3/093; F02P5/00; F02P5/04; F02P5/145; F02P5/155; F02P5/1553; F02P5/1555; F02P7/02; F02P7/03; F02P7/035; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
221 words
An ignition system, comprising: ignition means operable in response to trigger signals for producing corresponding ignition pulses to operate an internal combustion engine, trigger means for supplying trigger signals to said ignition means in timed relation with a movement of the piston of the engine, said trigger means including a trigger coil operably associated with the piston for supplying trigger signals to said ignition means and a magnetic trigger rotor rotatable about an axis past said trigger coil in synchronism with the movement of the piston for generating a trigger signal in said trigger coil, said trigger rotor having a peripheral portion constructed of magnetically conductive material with a substantially radial slot formed therein to provide an air gap rotatable past said trigger coil in close proximity and having magnetic means providing magnetic poles of opposite polarity on opposite sides of the radial slot in said peripheral portion to establish across the air gap a magnetic field with flux reversal for generating a trigger signal of maximum magnitude at relative low engine speeds, and said trigger rotor having a notch formed in said peripheral portion adjacent the radial slot for providing a reduced flux density through the trigger coil to generate an advanced trigger signal suitable for producing an advanced ignition pulse upon acceleration of the engine to a predetermined speed.
Claim 2
Dependent Claim
221 words
An ignition system, comprising: ignition means operable in response to trigger signals for producing corresponding ignition pulses to operate an internal combustion engine, trigger means for supplying trigger signals to said ignition means in timed relation with a movement of the piston of the engine, said trigger means including a trigger coil operably associated with the piston for supplying trigger signals to said ignition means and a magnetic trigger rotor rotatable about an axis past said trigger coil in synchronism with the movement of the piston for generating a trigger signal in said trigger coil, said trigger rotor having a peripheral portion constructed of magnetically conductive material with a substantially radial slot formed therein to provide an air gap rotatable past said trigger coil in close proximity and having magnetic means providing magnetic poles of opposite polarity on opposite sides of the radial slot in said peripheral portion to establish across the air gap a magnetic field with flux reversal for generating a trigger signal of maximum magnitude at relative low engine speeds, and said trigger rotor having a notch formed in said peripheral portion adjacent the radial slot for providing a reduced flux density through the trigger coil to generate an advanced trigger signal suitable for producing an advanced ignition pulse upon acceleration of the engine to a predetermined speed.
Claim 3
Dependent Claim
135 words
An ignition system according to claim 1, the combination further comprising: a plurality of trigger coils each operably associated with a different piston of an internal combustion engine having a plurality of pistons and being arranged about the rotatable path of said trigger rotor for supplying trigger signals to said ignition means in timed relation with the movement of the different pistons, and said trigger rotor having an outer member of magnetically conductive material arranged in an eccentric configuration with said radial slot being formed in a peripheral portion furthest from the axis of rotation of said trigger rotor to provide an intervening air gap between the outer member and the plurality of trigger coils which increases with the circumferential distance from the radial slot to prevent operation of the engine in a reverse direction.
Claim 4
Dependent Claim
47 words
An ignition system according to claim 2: said magnetic means being in the form of a ring, said outer member being formed by tapered arcuate sectors, and said trigger rotor further including nonmagnetically conductive material located radially opposite said radial slot for rotatably counterbalancing said trigger rotor.
Claim 5
Dependent Claim
63 words
An ignition system according to claim 2: said magnetic means being in the form of a ring concentric with the axis of rotation of said rotor, and said trigger rotor further including a cup constructed of nonmagnetically conductive material receiving said eccentric configuration of magnetically conductive material and being eccentrically positioned relative to the axis of rotation for rotatably counterbalancing said trigger rotor.
Claim 6
Dependent Claim
163 words
An ignition system according to claim 2: said trigger rotor being constructed from a single piece of magnetically conductive material having arcuate shaped slots formed therethrough and extending from adjacent the radial slot to a generally diametrically opposite location to form inner and outer segments secured together by a pair of radially extending leg portions defining the radial gap and a bridge portion generally diametrically opposite the radial slot of the trigger rotor, said magnetic means being in the form of arcuate shaped magnets received in said arcuate shaped slots, said bridge portion serving as a magnetic short for shorting the magnetic flux associated with the adjacent end portions of said arcuate shaped magnets, and said pair of magnetically conductive leg portions serving as flux chokes for diverting the flux associated with the adjacent magnets across the air gap to provide a highly concentrated field for inducing trigger signals in said trigger coils upon rotation of the radial gap past said trigger coils.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-08 | 1979-12-08 | 1980-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-08 | 1983-12-08 | 1984-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-08 | 1987-12-08 | 1988-06-08 | $7700.00 | Window Closed / Lapsed |