EP0205225A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
An electromagnetic detection system, as well as a responder for such a system
Assignee: Nederlandsche Apparatenfabriek NEDAP NV
•
Filing: 1986-06-13
•
Granted: —
•
Expires: 2006-06-13
Abstract
Abstract An electromagnetic detection system comprising transmission means producing in at least one first spatial detection zone an electromagnetic interrogation field; plurality of responders having attachment means for attachment to articles to be protected, each including a resonant circuit and if present in a detection zone, in response to the interrogation field, producing a signal; and first detection means adapted to detect a responder and, on detection of a responder, to produce a warning signal. According to the invention, the responders are designed in such a manner that when the attachment means are removed or when a responder is damaged, at least one frequency determining parameter of the responder is changed in a predetermined manner. At least one second spatial detection zone is provided wherein responders with the at least one changed frequency determining parameter can be detected.
Inventors
- 👤 Johannes Harm Lukas Hogen Esch
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 02:34
CPC Classifications
E; E05; E05B; E05B73/00; E05B73/0017; G; G08; G08B; G08B13/00; G08B13/22; G08B13/24; G08B13/2402; G08B13/2405; G08B13/2414; G08B13/2417; G08B13/2422; G08B13/2425; G08B13/2428; G08B13/2431; G08B13/2434; G08B13/2437; G08B13/2442
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
139 words
An electromagnetic detection system comprising transmission means producing in at least one first spatial detection zone an electromagnetic interrogation field; a plurality of responders having attachment means for attachment to articles to be protected, each including a resonant circuit and which, if present in a detection zone, in response to the interrogation field, produce a signal; and first detection means adapted to detect a responder and, on detection of a responder, to produce a warning signal, characterized in that the responders are designed in such a manner that when the attachment means are removed or when a responder is damaged, at least one frequency determining parameter of the responder is changed in a predetermined- manner and that at least one second spatial zone is provided wherein responders with the at least one changed frequency determining parameter can be detected.
Claim 2
Dependent Claim
139 words
An electromagnetic detection system comprising transmission means producing in at least one first spatial detection zone an electromagnetic interrogation field; a plurality of responders having attachment means for attachment to articles to be protected, each including a resonant circuit and which, if present in a detection zone, in response to the interrogation field, produce a signal; and first detection means adapted to detect a responder and, on detection of a responder, to produce a warning signal, characterized in that the responders are designed in such a manner that when the attachment means are removed or when a responder is damaged, at least one frequency determining parameter of the responder is changed in a predetermined- manner and that at least one second spatial zone is provided wherein responders with the at least one changed frequency determining parameter can be detected.
Claim 3
Dependent Claim
34 words
An electromagnetic detection system according to claim 1, characterized in that at least one of the second spatial detection zones coincides at least partly with at least one of the first spatial detection zones.
Claim 4
Dependent Claim
37 words
An electromagnetic detection system according to claim 2, characterized in that the first detection means associated with the coinciding detection zones are adapted to also detect a responder a frequency determining parameter of which has been changed.
Claim 5
Dependent Claim
53 words
An electromagnetic detection system according to claim 1, characterized in that each responder comprises at least one connection wire extending along the edge of the responder, said wire forming an electric connection between a frequency determining component of the electric circuit of the responder and other frequency determining components of the responder circuit.
Claim 6
Dependent Claim
32 words
An electromagnetic detection system according to claim 4, characterized in that the responder circuit comprises at least two parallel-connected coils and that the connection wire forms a connectino between the two coils.
Claim 7
Dependent Claim
31 words
An electromagnetic detection system according to claim 4, characterized in that the responder circuit comprises at least two serially connected coils and that the connection wire bypasses one of the coils.
Claim 8
Dependent Claim
20 words
An electromagnetic detection system according to claim 5, characterized in that the connection wire also forms one of the coils.
Claim 9
Dependent Claim
32 words
An electromagnetic detection system according to claim 4, characterized in that the responder circuit comprises at least two parallel capacitors and that the connection wire forms a connection between the two capacitors.
Claim 10
Dependent Claim
30 words
An electromagnetic detection system according to claim 4, characterized in that the responder circuit comprises at least two series-connected capacitors and that the connection wire bypasses one of the capacitors.
Claim 11
Dependent Claim
38 words
An electromagnetic detection system according to claim 4, characterized in that the responder circuit comprises a non-linear element and that the connection wire connects the non-linear element to the rest of the circuit or bypasses the non-linear element.
Claim 12
Dependent Claim
59 words
ll. An electromagnetic detection system according to claim 1, characterized in that each responder comprises at least one connection circuit forming an electric connectbn between a frequency determining component of the electric circuit of the responder and other frequency determining components of the responder, with the connection circuit being closed by at least a part of the attachment means.
Claim 13
Dependent Claim
23 words
An electromagnetic detection system according to claims 4 and 11, characterized in that the connection circuit comprises the at least one connection wire.
Claim 14
Dependent Claim
89 words
An electromagnetic detection system according to claim 11, in which the responder included a lock adapted to receive an end of a conductive pin, the free end of the pin being connected to the responder by means of a flexible strip, characterized in that the connection circuit comprises a conductor extending through the flexible strip, which conductor is connected to the free end of the conductive pin, the connection circuit further comprising at least one contact member disposed in the responder and being adapted to coact with the pin.
Claim 15
Dependent Claim
61 words
An electromagnetic detection system according to claim 11, in which the responder includes a lock adapted to receive the end of a conductive pin, characterized in that the pin is designed as a plug member having two isolated portions, each adapted to coact with an associated contact member in the responder and electrically connected adjacent the free end of the pin.
Claim 16
Dependent Claim
19 words
An electromagnetic detection system according to claim 14, characterized in that the pin is designed as a coaxial plug.
Claim 17
Dependent Claim
52 words
An electromagnetc detection system according - to claim 11 or 12, characterized in that the attachement means comprise a magnet and that the connection circuit includes a reed switch disposed with the rsponder, the position of said switch being defined by the magnet when the attachment means are in the closed position.
Claim 18
Dependent Claim
16 words
A responder destined for a detection system * according to any one of teh preceding claims.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.