MULTIPLE-CONDITION AUTOMOTIVE ALARM SYSTEM
First Claim
1. A multiple-condition alarm system for a motor vehicle having an ignition switch having a hot side connected to a source of electrical potential and a cold side, said alarm system comprising an electrically operated audible alarm unit having a pair of terminals, a distribution circuit including first and second branches each connected to one of said alarm-unit terminals, a plurality of switches each responsive to a particular condition within said vehicle, a first group of said switches connected to the hot side of said ignition switch and a second group of said switches connected to the cold side of said ignition switch, a plurality of lead wires connecting said first and second groups of switches to the first and second branches respectively of said distribution circuit, and a lead wire connecting the cold side of said ignition switch to the first branch of said distribution circuit, whereby the closure of a switch of said first group only while said ignition switch is open or the closure of a switch of said second group only while said ignition switch is closed will cause said alarm unit to be energized.
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Accused Products
Abstract
An electrical audible alarm unit connected across a vehicle battery through a number of switches for indicating the presence of one of a number of conditions or malfunctions. Isolation diodes are used at avoid the coupling of electrical circuits within the vehicle. Switches may be connected to both terminals of the alarm unit, with or without isolation diodes, to provide a warning signal only when certain conditions are met.
7 Citations
9 Claims
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1. A multiple-condition alarm system for a motor vehicle having an ignition switch having a hot side connected to a source of electrical potential and a cold side, said alarm system comprising an electrically operated audible alarm unit having a pair of terminals, a distribution circuit including first and second branches each connected to one of said alarm-unit terminals, a plurality of switches each responsive to a particular condition within said vehicle, a first group of said switches connected to the hot side of said ignition switch and a second group of said switches connected to the cold side of said ignition switch, a plurality of lead wires connecting said first and second groups of switches to the first and second branches respectively of said distribution circuit, and a lead wire connecting the cold side of said ignition switch to the first branch of said distribution circuit, whereby the closure of a switch of said first group only while said ignition switch is open or the closure of a switch of said second group only while said ignition switch is closed will cause said alarm unit to be energized.
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2. The alarm system of claim 1 wherein said first group of switches includes a switch for a system oF external lighting for said vehicle.
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3. The alarm system of claim 1 wherein at least one of the branches of said distribution circuit includes a plurality of diodes for isolating certain of said leads from others in the same branch.
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4. The alarm system of claim 1 wherein one of said switches is normally closed and wherein the opening of said switch triggers a circuit including a silicon-controlled rectifier and connected to said distribution circuit to cause said alarm unit to be energized and to remain energized until electrical power is removed therefrom.
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5. The alarm system of claim 1 wherein said first group of switches includes a switch for a radio of said vehicle.
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6. The alarm system of claim 1 wherein said second group of switches includes a switch for the oil pressure system of said vehicle.
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7. The alarm system of claim 1 wherein said second group of switches includes a switch for the temperature-indicating system for said vehicle.
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8. The alarm system of claim 1 wherein said second group of switches includes a switch energizing the dome light for said vehicle.
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9. The alarm system of claim 1 wherein said second group of switches includes a switch for the master brake cylinder of said vehicle.
Specification