Metal detector coil
First Claim
1. A walk-through, person-screening metal detector comprising bistatic coil means in a portal with transmitting coil means on one side and receiving coil means on the opposite side of the portal, said transmitting coil means being multiple coils and having changeable interconnection means for changing a field pattern in local regions of the portal to compensate for the effects of adjacent metal near t portal, and with gaps between adjacent parts of said multiple coils for adjustably controlling sensitivity variations within a volume contained by the receiving coil means disposed on said portal to intercept a field induced in a contraband item by the transmit coil means, detector means coupled to said coils, and alarm means responsive to said detector means for reporting contraband metal passing the portal.
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Accused Products
Abstract
A coil for a metal detector is constructed from a ribbon cable having a plurality of spaced parallel conductors. The ribbon is formed into a loop where its opposing ends confront each other. The conductors are joined in an off-set manner at the end of the cable to form a single conductor into a loop. Various configurations of coil placement are shown to compensate for various external disturbances such as nearby metal objects, for example.
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Citations
12 Claims
- 1. A walk-through, person-screening metal detector comprising bistatic coil means in a portal with transmitting coil means on one side and receiving coil means on the opposite side of the portal, said transmitting coil means being multiple coils and having changeable interconnection means for changing a field pattern in local regions of the portal to compensate for the effects of adjacent metal near t portal, and with gaps between adjacent parts of said multiple coils for adjustably controlling sensitivity variations within a volume contained by the receiving coil means disposed on said portal to intercept a field induced in a contraband item by the transmit coil means, detector means coupled to said coils, and alarm means responsive to said detector means for reporting contraband metal passing the portal.
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5. A coil array for a walk-through, pulsed-field metal detector, said array comprising:
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a. first receiver coil means having four loops of conductor material, constructed from a ribbon cable with no dipolar or quadrupolar moment, and with gaps between conductors of adjacent coils; b. second receiver coil means constructed similar to and inverted with respect to said first receiver coils; c. said first and second coils being aligned so that the least sensitive zone of said first coil coincides with the most sensitive zone of the second coil and vice versa. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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Specification