US3718128A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ignition interlock system
Assignee: Philips North America LLC
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Filing: 1971-08-20
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Granted: 1973-02-27
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Expires: 1991-08-20
Abstract
Abstract An interlock circuit grounded at one side and having one wire connected to the ignition magneto of a gasoline engine. A second wire is connected to a switch on the transmission to actuate the circuit to be a short circuit across the magneto when the engine is not running, except when the transmission is in neutral. The circuit automatically disables itself after the engine starts.
Inventors
- 👤 K Botker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:41
CPC Classifications
F; F02; F02N; F02N11/00; F02N11/10; F02N11/101; F02N11/105; F02P; F02P1/00; F02P1/08; F02B; F02B1/00; F02B1/02; F02B1/04
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
268 words
A circuit to control the starting of a magneto ignition engine having power take-off means movable between at least one safe condition and one other condition and in which the magneto has a voltage supplying terminal and ground, said circuit comprising: A. A silicon-controlled rectifier comprising: 1. an output circuit connected between said terminal and ground to short-circuit said magneto and prevent it from producing ignition pulses when said rectifier is conductive, and 2. an input circuit; B. A transistor comprising: 1. an output circuit connected across the gate and cathode terminals of said silicon-controlled rectifier to prevent said rectifier from becoming conductive when said transistor is conductive, and 2. an input circuit; C. Means to supply voltage impulses from said magneto to said rectifier to tend to cause said rectifier to become condUctive in response to each of said impulses; D. Means to supply voltage impulses from said magneto to said transistor to cause said transistor to become conductive upon the occurrence of each of said impulses prior to said rectifier''s becoming conductive; E. Means to prevent said last-named impulses from making said transistor conductive until the engine is running; and F. A switch having one side connected to ground and being mechanically controlled by the power take-off mechanism to be closed only when the power take-off mechanism is in said safe condition to allow the engine to start, the other terminal of said switch being connected to said transistor to effect a short-circuit condition across said input circuit of said silicon-controlled rectifier at least during the occurrence of each of the voltage impulses from said magneto.
Claim 2
Dependent Claim
268 words
A circuit to control the starting of a magneto ignition engine having power take-off means movable between at least one safe condition and one other condition and in which the magneto has a voltage supplying terminal and ground, said circuit comprising: A. A silicon-controlled rectifier comprising: 1. an output circuit connected between said terminal and ground to short-circuit said magneto and prevent it from producing ignition pulses when said rectifier is conductive, and 2. an input circuit; B. A transistor comprising: 1. an output circuit connected across the gate and cathode terminals of said silicon-controlled rectifier to prevent said rectifier from becoming conductive when said transistor is conductive, and 2. an input circuit; C. Means to supply voltage impulses from said magneto to said rectifier to tend to cause said rectifier to become condUctive in response to each of said impulses; D. Means to supply voltage impulses from said magneto to said transistor to cause said transistor to become conductive upon the occurrence of each of said impulses prior to said rectifier''s becoming conductive; E. Means to prevent said last-named impulses from making said transistor conductive until the engine is running; and F. A switch having one side connected to ground and being mechanically controlled by the power take-off mechanism to be closed only when the power take-off mechanism is in said safe condition to allow the engine to start, the other terminal of said switch being connected to said transistor to effect a short-circuit condition across said input circuit of said silicon-controlled rectifier at least during the occurrence of each of the voltage impulses from said magneto.
Claim 3
Dependent Claim
7 words
an input circuit; B. A transistor comprising:
Claim 4
Dependent Claim
7 words
an input circuit; B. A transistor comprising:
Claim 5
Dependent Claim
158 words
an input circuit; C. Means to supply voltage impulses from said magneto to said rectifier to tend to cause said rectifier to become condUctive in response to each of said impulses; D. Means to supply voltage impulses from said magneto to said transistor to cause said transistor to become conductive upon the occurrence of each of said impulses prior to said rectifier''s becoming conductive; E. Means to prevent said last-named impulses from making said transistor conductive until the engine is running; and F. A switch having one side connected to ground and being mechanically controlled by the power take-off mechanism to be closed only when the power take-off mechanism is in said safe condition to allow the engine to start, the other terminal of said switch being connected to said transistor to effect a short-circuit condition across said input circuit of said silicon-controlled rectifier at least during the occurrence of each of the voltage impulses from said magneto.
Claim 6
Dependent Claim
158 words
an input circuit; C. Means to supply voltage impulses from said magneto to said rectifier to tend to cause said rectifier to become condUctive in response to each of said impulses; D. Means to supply voltage impulses from said magneto to said transistor to cause said transistor to become conductive upon the occurrence of each of said impulses prior to said rectifier''s becoming conductive; E. Means to prevent said last-named impulses from making said transistor conductive until the engine is running; and F. A switch having one side connected to ground and being mechanically controlled by the power take-off mechanism to be closed only when the power take-off mechanism is in said safe condition to allow the engine to start, the other terminal of said switch being connected to said transistor to effect a short-circuit condition across said input circuit of said silicon-controlled rectifier at least during the occurrence of each of the voltage impulses from said magneto.
Claim 7
Dependent Claim
20 words
The circuit of claim 1 in which said switch is connected in parallel with the output circuit of said transistor.
Claim 8
Dependent Claim
50 words
an input circuit; B. A capacitor connected across said input circuit of said semiconductor device; and C. A charging circuit connected to said capacitor to supply repetitive incremental charges thereto at each firing of said magneto to charge said capacitor to a voltage level to render said semiconductor device non-conductive.
Claim 9
Dependent Claim
50 words
an input circuit; B. A capacitor connected across said input circuit of said semiconductor device; and C. A charging circuit connected to said capacitor to supply repetitive incremental charges thereto at each firing of said magneto to charge said capacitor to a voltage level to render said semiconductor device non-conductive.
Claim 10
Dependent Claim
20 words
The circuit of claim 1 in which said switch is connected between ground and said input circuit of said transistor.
Claim 11
Dependent Claim
43 words
The circuit of claim 3 comprising, in addition: A. A first voltage divider connected in series with said switch and said terminal of said magneto; and B. A connection between one part of said voltage divider and said input circuit of said transistor.
Claim 12
Dependent Claim
37 words
The circuit of claim 4 comprising, in addition, a first diode connected between said voltage divider and said input circuit of said transistor to permit voltage impulses of only one polarity to be applied to said transistor.
Claim 13
Dependent Claim
59 words
The circuit of claim 5 comprising, in addition: A. A second diode and a second voltage divider connected in series between said magneto terminal and ground; and B. A connection between one section of said second voltage divider and said input circuit of said transistor to provide a second circuit for supplying pulses from said magneto to said transistor.
Claim 14
Dependent Claim
42 words
The circuit of claim 6 comprising, in addition, a second diode connected in series between said section of said second voltage divider and said input circuit of said transistor and polarized to prevent undesired coupling between said first and second voltage dividers.
Claim 15
Dependent Claim
40 words
The circuit of claim 6 comprising, in addition: A. A semiconductor device connected in parallel with said portion of said second voltage divider; and B. Means responsive to repetitive voltage pulses from said magneto to render said semiconductor device non-conductive.
Claim 16
Dependent Claim
29 words
The circuit of claim 1 in which said means to prevent said impulses from making said transistor conductive until the engine is running comprise: A. A semiconductor device comprising:
Claim 17
Dependent Claim
61 words
The circuit of claim 9 in which said charging circuit comprises: A. A second capacitor; B. A first diode connecting said second capacitor to said magneto; and C. A second diode connecting said second capacitor to said first-named capacitor to transfer charge from said second capacitor to said first-named capacitor upon the occurrence of each magneto pulse of the proper polarity.
Claim 18
Dependent Claim
55 words
The circuit of claim 10 comprising, in addition: A. A first resistor connected in series with said second capacitor and in a closed loop series circuit with said first-named capacitor and said second diode; and B. A second resistor connected in series with said second capacitor and said first resistor in a second closed loop.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |