TAG FOR BURGLAR PREVENTION AND DOOR OPENING ALARMING DEVICE

摘要

PROBLEM TO BE SOLVED: To make surely detachable whether or not a tag is separated from a metallic article or whether or not a door is opened and to issue an alarm. SOLUTION: For this tag for burglar prevention, a non-magnetic case 18 is attached to the soft magnetic body part 11a of an article 11 for burglar monitoring and a resonance circuit part 14 for resonating to the radio waves of a specified frequency, a permanent magnet 19 facing the soft magnetic body part 11a, a reed switch 16 and an alarming means 17 for issuing the alarm when the switch 16 is closed are incorporated in the case 18. A main magnetic path is formed between the magnet 19 and the soft magnetic body part 11a and the switch 16 is opened in the attached state of the case 18 and the magnetic path for the alarm is formed between the magnet 19 and the switch 16 and the switch 16 is closed in the detached state of the case 18. For this door opening alarming device, the case is attached to a frame for a door for abutting the door when the door is closed or the door and the door or the frame for the door facing the case is a soft magnetic body or is provided with the soft magnetic body.