Burglar alarm system
OwnerCharles Querciainventor
Life of this patent
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Abstract
A protective alarm system for a vehicle or the like wherein a protective switch initiates operation of a circuit combining two timing effects : effecting time delaying of an alarm device, and determining the duration of the alarm. Once initiated by the protective switch, the alarm is actuated after a predetermined delay and for a predetermined duration despite any action on the switch such as a periodical opening and closing. Circuitry operated by a key switch defeats instantaneously actuation of the alarm system when a further manually operated knob is on, which results in a necessary order of operation, involving the possession of the key, to inhibit definitely the alarm.
Claims4
An alarm system for use in a vehicle to detect unauthorized entry into the vehicle, comprising:
- A. a first switch means positioned to be operated when a door of the vehicle is opened,
- B. a key-operated switch means having at least first and second switch conditions, normally being in the first condition when the vehicle is empty, and adapted to be placed in the second condition by insertion and operation of a key,
- C. a two-position switch means which is manually operable between first and second switch positions,
- D. alarm means for giving an alarm when operated,
- E. disabling means operative only when the key-operated switch is in the second condition and responsive to placement of the two-position switch in the second switch position for disabling the alarm system,
- F. first delay means, operative only when the two-position switch is in the first switch position, and responsive to the act of placing the key-operated switch in the first condition, for beginning to measure a first delay interval,
- G. second delay means, fully operative only after the first delay interval has been measured to its conclusion, and responsive to operation of the first switch means, for beginning to measure a second delay interval, and
- H. third delay means, operative unless and until inhibited by placement of the key-operated switch means in the second condition, for defining a third delay interval during which the alarm means is operated.
For use in a vehicle having a d.c. power supply, an alarm system for providing an alarm in response to unauthorized entry into the vehicle, said system comprising:
- A. switch means operated by said entry,
- B. alarm means,
- C. alarm energizing means connected to operate said alarm means, the energizing means being provided with an input terminal and, when activated by an activating signal to said input terminal, energizing said alarm means to produce said alarm, and
- D. activating means connected to said switch means for activating said alarm energizing means after a predetermined delay and during a predetermined duration in response to the operation of said switch means, wherein said activating means comprises
- 1. an input capacitor connected across the terminals of said power supply through a circuit including said switch means,
- 2. a first resistor shunting said input capacitor,
- 3. an output capacitor coupled to said input capacitor through a second resistor shunted by a diode, and
- 4. means for connecting said input terminal to the common terminal of said output capacitor and said second resistor.
Dependencies are inferred from the claim text.