Antitheft system

• US 20050099296A1
• Filed: 04/17/2002
• Published: 05/12/2005
• Est. Priority Date: 04/20/2001
• Status: Active Grant

• Current Assignee: Tyco Fire & Security GmbH (Johnson Controls International plc)
• Original Assignee: Sensormatic Electronics Corporation (Johnson Controls International plc)
• Inventors: Matsudaira, Shinji, Yoshida, Hiroshi
• Granted Patent: US 7,224,276 B2
• Time in Patent Office: Days
• US Class Current: 340/566
• CPC Class Codes: G08B 1/08 using electric transmission ; transformation of alarm signals to electrical signals from a different medium, e.g. transmission of an electric alarm signal upon detection of an audible alarm signal
• CPC Class Codes: G08B 13/1445 with detection of interference with a cable tethering an article, e.g. alarm activated by detecting detachment of article, breaking or stretching of cable furniture, e.g. shelves for displaying merchandise, incorporating tethers to prevent theft A47F7/024, A47F5/0861
• CPC Class Codes: G08B 13/2402 Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting mechanical aspects of the tags, e.g. related to locking E05B73/0017; RFID readers G06K7/00; RFID tags G06K19/00; access control systems G07C9/00; anti-theft control in point of sale systems G07G3/003; security seals G09F3/03

Abstract

The present invention provides a burglar alarm system capable of accurately discriminating an alarm from a disturbance noise approximate to the alarm such as background music, ambient noises, etc. In a burglar alarm system comprising an alarm unit attached to an object to be protected from theft to emit an alarm of a particular frequency and an alarm sensor device for issuing an alarm signal upon sensing an alarm from the alarm unit, the alarm sensor device counts a predetermined number of waveform pulses of a received sound (S2, S5) more than once (S1˜S3, S4˜S6), determines, if it transpires that a differential between counted values falls within a predetermined time range, that the received sound is an alarm and issues an alarm signal (S7).

Claims

1. A burglar alarm system comprising an alarm unit attached to an object to be protected from theft to emit an alarm of a particular frequency in response to wrongful conduct and an alarm sensor device for emitting an alarm signal upon sensing an alarm from said alarm unit,

said alarm sensor device counting a predetermined number of waveform pulses of a received sound more than once, determining, if a differential between counted values falls within a specified time range, that said received sound is an alarm and issuing an alarm signal.

2. A burglar alarm system comprising an alarm unit attached to an object to be protected from theft to emit an alarm of a particular frequency in response to wrongful conduct and an alarm sensor device for emitting an alarm signal upon sensing an alarm from said alarm unit,

an alarm emitted from said alarm unit having an intermittent waveform of a constant cycle,

said alarm sensor device counting a predetermined number of waveform pulses of said alarm more than once while said alarm is continuing, determining, if a differential between counted values falls within a predetermined time range and that an intermittent cycle of said received sound matches an intermittent cycle of said alarm signal, that said received sound is an alarm and issuing an alarm signal and issuing an alarm signal.

3. The burglar alarm system as defined in claim 2, wherein determination based on a differential between said counted values and determination based on matching between said intermittent cycles are made more than once, thereby adjusting a sensitivity level.