Wafer and fastener for use in electronic theft detection system
First Claim
1. A target wafer for use in an electronic theft detection system, said wafer comprising upper and lower members which are generally flat and coextensive and which are laminated to each other, one of said members having a continuous, spiral shaped groove formed in the surface thereof facing the other member, an elongated electrical conductor lying in said groove, a capacitor also contained between said members, said capacitor being electrically connected to said electrical conductor near each end thereof to form a resonant electrical circuit.
1 Assignment
0 Petitions
Accused Products
Abstract
A wafer construction which includes an expansive, generally flat plastic member formed with a spiral groove in which an elongated electrical conductor is held in the shape of a coil. The plastic member is also formed with a recess in which a capacitor is contained. The capacitor is connected to both ends of the conductor to form a resonant electrical circuit. A hardened steel reinforcing element is also embedded in the wafer around the wafer circuits to protect them against severing. A tack-like fastener element has a concave head which telescopes over a dome-like projection on the wafer to provide a tamper resistant fastening assembly when the tack shank is inserted into an opening in the wafer.
-
Citations
12 Claims
- 1. A target wafer for use in an electronic theft detection system, said wafer comprising upper and lower members which are generally flat and coextensive and which are laminated to each other, one of said members having a continuous, spiral shaped groove formed in the surface thereof facing the other member, an elongated electrical conductor lying in said groove, a capacitor also contained between said members, said capacitor being electrically connected to said electrical conductor near each end thereof to form a resonant electrical circuit.
- 10. A target wafer for use in an electronic theft detection system, said wafer comprising upper and lower members which are generally flat and coextensive and which are laminated to each other, one of said members having a continuous, spiral shaped groove formed in the surface thereof facing the other member, means forming an electrical circuit embedded within said spiral groove and capable of cooperating with an electronic theft detection system to produce characteristic signal disturbances, and a hardened metal ring also embedded inside said wafer and surrounding said electrical circuit to protect said circuit from damage due to severing of said wafer.
Specification