US3868518A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automobile theft alarm with ignition controlled automatic arming means
Assignee: Harrison Systems Corp
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Filing: 1972-12-04
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Granted: 1975-02-25
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Expires: 1992-12-04
Abstract
Abstract A vehicle alarm system adapted to provide a pulsed actuation of an audible alarm upon unauthorized entry is provided with means to automatically rearm the circuit a predetermined interval after the ignition switch is turned off. The alarm is activated by a pulse generating circuit which is energized by a sensing circuit responsive to the rate of change of voltage at the vehicle battery terminals and is latched in its energized condition until the ignition switch is turned on. Means are provided to render the sensing circuit ineffective while the ignition switch is on and for a predetermined interval after it is turned off to allow the driver sufficient time to exit the vehicle. The pulse generating circuit is provided with an inherent initial time delay to provide the driver sufficient time to enter the vehicle and turn the ignition switch on. Means are provided for disarming the circuit when the ignition switch is turned to the accessory position and held in such position for a predetermined time interval, failing which the circuit will be automatically rearmed upon turning the ignition off. The practical effectiveness of the system is greatly enhanced by the requirement that the driver take positive action to disarm the alarm.
Inventors
- 👤 Rudor M Teich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:28
CPC Classifications
H; H03; H03K; H03K3/00; H03K3/02; H03K3/35; H03K3/351; B; B60; B60R; B60R25/00; B60R25/10; B60R25/1003; B60R2025/1013; B60R25/1004
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
341 words
A pulse generator having an initial time delay and adapted to provide, following said time delay, a pulsating switching action to provide pulsed actuation of an electrical element, comprising a voltage source, first switch means operatively connected in series with said electrical element between said voltage source and a reference voltage node, second switch means connected in series with said electrical element between said voltage source and ground, said second switch means having a control terminal, first and second resistors, a first junction node connected to said reference voltage node through said first resistor, a second junction node connected to said electrical element and said second switch means at the series connection therebetween through said second resistor, a first capacitor operatively connected between said first and second junction nodes and capacitively coupling same, a second capacitor operatively connected between said first junction node and ground, third switch means responsive to the voltage at said first junction node and adapted, upon increase of the voltage thereat to a predetermined level, to conductively connect said first and second junction nodes to the control terminal of said second switch means, thereby to render said second switch means conductive, whereby upon the closing of said first switch means said first junction node is charged through said first resistor to said predetermined voltage level during a first time interval defining said initial delay, at which time said third switch means operatively connects said control terminal of said second switch means to said voltage source to actuate same, thereby producing a large current through said electrical element and shunting said first resistor, whereupon the voltage at said first junction node falls below said predetermined level and said third switch means is rendered nonconductive disconnecting the control terminal of said second switch means from said voltage source to render said second switch means nonconductive thereby terminating said large current and beginning a new cycle, said first junction node thereafter being rapidly charged to said pedetermined level, at least in part by the capacitive coupling of said first capacitor.
Claim 2
Dependent Claim
341 words
A pulse generator having an initial time delay and adapted to provide, following said time delay, a pulsating switching action to provide pulsed actuation of an electrical element, comprising a voltage source, first switch means operatively connected in series with said electrical element between said voltage source and a reference voltage node, second switch means connected in series with said electrical element between said voltage source and ground, said second switch means having a control terminal, first and second resistors, a first junction node connected to said reference voltage node through said first resistor, a second junction node connected to said electrical element and said second switch means at the series connection therebetween through said second resistor, a first capacitor operatively connected between said first and second junction nodes and capacitively coupling same, a second capacitor operatively connected between said first junction node and ground, third switch means responsive to the voltage at said first junction node and adapted, upon increase of the voltage thereat to a predetermined level, to conductively connect said first and second junction nodes to the control terminal of said second switch means, thereby to render said second switch means conductive, whereby upon the closing of said first switch means said first junction node is charged through said first resistor to said predetermined voltage level during a first time interval defining said initial delay, at which time said third switch means operatively connects said control terminal of said second switch means to said voltage source to actuate same, thereby producing a large current through said electrical element and shunting said first resistor, whereupon the voltage at said first junction node falls below said predetermined level and said third switch means is rendered nonconductive disconnecting the control terminal of said second switch means from said voltage source to render said second switch means nonconductive thereby terminating said large current and beginning a new cycle, said first junction node thereafter being rapidly charged to said pedetermined level, at least in part by the capacitive coupling of said first capacitor.
Claim 3
Dependent Claim
54 words
The pulse generator of claim 1, wherein said third switch means is a unijunction transistor having its emitter connected to said first junction node and one of its bases connected to said second junction node and the other base of said unijunction transistor operatively connected to the control terminal of said second switch means.
Claim 4
Dependent Claim
31 words
The pulse generator of claim 1, wherein said first switch means comprises a siLicon controlled rectifier, said second switch means being connected to said electrical element through said silicon controlled rectifier.
Claim 5
Dependent Claim
13 words
The pulse generator of claim 3, wherein said electrical element comprises a relay.
Claim 6
Dependent Claim
17 words
The pulse generator of claim 4, wherein said first capacitor is much larger than said second capacitor.
Claim 7
Dependent Claim
22 words
The pulse generator of claim 5, wherein the ratio between the capacitances of said first and second capacitors is 5 to 1.
Claim 8
Dependent Claim
88 words
The pulse generator of claim 1, further comprising a third resistor operatively connected between said third switch means and the control terminal of said second switch means and a third capacitor operatively connected in series with said third resistor between the control terminal of said second switch means and ground, said third capacitor being adapted to be charged through said third switch means, the interval of said pulsed actuation of said electrical element being a function of the discharge time of said third capacitor through said third resistor.
Claim 9
Dependent Claim
31 words
The pulse generator of claim 7, wherein said first switch means comprises a silicon controlled rectifier, said second switch means being connected to said electrical element through said silicon controlled rectifier.
Claim 10
Dependent Claim
13 words
The pulse generator of claim 8, wherein said electrical element comprises a relay.
Claim 11
Dependent Claim
17 words
The pulse generator of claim 9, wherein said first capacitor is much larger than said second capacitor.
Claim 12
Dependent Claim
22 words
The pulse generator of claim 10, wherein the ratio between the capacitances of said first and second capacitors is 5 to 1.
Claim 13
Dependent Claim
94 words
The pulse generator of claim 2, further comprising a third resistor operatively connected between said other base of said unijunction transistor and the control terminal of said second switch means and a third capacitor operatively connected in series with said third resistor between the control terminal of said second switch means and ground, said third capacitor being adapted to be charged through said other base of said unijunction transitor, the interval of said pulsed actuation of said electrical element being a function of the discharge time of said third capacitor through said third resistor.
Claim 14
Dependent Claim
17 words
The pulse generator of claim 12, wherein said first capacitor is much larger than said second capacitor.
Claim 15
Dependent Claim
40 words
The pulse generator of claim 12, further comprising a fourth resistor operatively connected between said other base of said unijunction transistor and ground, and diode means operatively connected between said other base of said unijunction transitor and said third resistor.
Claim 16
Dependent Claim
17 words
The pulse generator of claim 14, wherein said first capacitor is much larger than said second capacitor.
Claim 17
Dependent Claim
44 words
The pulse generator of claim 12, further comprising a fourth capacitor operatively connected in series with said first resistor between said emitter and said other base of said unijunction transistor, thereby to back bias said unijunction transistor upon conduction of said second switch means.
Claim 18
Dependent Claim
17 words
The pulse generator of claim 16, wherein said first capacitor is much larger than said second capacitor.
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) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |