EP 0116701 B1 19870603 - ANTI-THEFT DEVICE
Title (en)
ANTI-THEFT DEVICE
Publication
Application
Priority
- DE 3302459 A 19830126
- DE 3314187 A 19830419
Abstract (en)
[origin: EP0116701A1] 1. Anti-theft system for merchandise, having at least one source of surveillance current, at least one sensor which cooperates with the item of merchandise and is linked into the surveillance circuit and modifies the surveillance current if the merchandise is removed, and having a surveillance circuit which provides an alarm signal if a modification of the surveillance current is detected, where the unit comprising the sensor and the connection cable between the sensor and the surveillance circuit provides, when properly connected to the merchandise, a surveillance current which may be varied in terms of its amplitude and/or frequency and/or phase position to larger or smaller values, so as to produce a change in the amplitude and/or frequency and/or phase position of the surveillance current both if the connection between the sensor and the merchandise is broken and if the connection cable is short-circuited, characterized in that the surveillance circuit exhibits an activation circuit (138C, 142 ; 332, 334, 340-344 ; 332, 348, 350 ; 352, 354 ; 383) energized via a plug-in connector (14 ; 314) by a control current which also serves to link the sensor (100 ; 200 ; 318) to the surveillance circuit (16 ; 326), so as to produce a change in the surveillance current in terms of amplitude and/or frequency and/or phase position if the sensor and surveillance circuit become disconnected, but at the same time allowing the sensor and the surveillance circuit to be connected up without setting off an alarm.
IPC 1-7
IPC 8 full level
G08B 13/14 (2006.01); G08B 13/22 (2006.01)
CPC (source: EP)
G08B 13/1454 (2013.01); G08B 13/22 (2013.01)
Designated contracting state (EPC)
AT BE CH DE FR GB IT LI NL SE
DOCDB simple family (publication)
EP 0116701 A1 19840829; EP 0116701 B1 19870603; DE 3371951 D1 19870709
DOCDB simple family (application)
EP 83112050 A 19831201; DE 3371951 T 19831201