Metal detector with first and second nested rectangular coils
AssigneeXonics, Inc.
InventorsFrank E. Ambler, Carl James Duthler, Norton L. Moise
Life of this patent
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Abstract
An orthogonal coil metal detector with nesting rectangular coils, each comprising a plurality of turns encapsulated in an insulating material and having a layer of electrical resistive material thereon. An encapsulating material in the gap between the coils bonding the coils together. A fixture for supporting the coils in spaced relations and providing for translation and rotation of one coil relative to the other for adjusting the coil position to a minimum coupling condition, and for holding the coils in the adjusted condition during curing.
Claims19
In a two coil metal detector, the combination of:
- a first coil of rectangular configuration and comprising a plurality of turns of wire encapsulated in an insulating material and having a rectangular opening;
- a second coil of rectangular configuration and comprising a plurality of turns of wire encapsulated in an insulating material, with said second coil positioned in said first coil opening with the axes of said coils disposed substantially at a right angle;
- a first layer of electrical resistive material on said first coil;
- a second layer of electrical resistive material on said second coil, each of said layers of electrical resistive material having a resistance in the range of about 1,000 to about 100,000 ohms per square unit of area;
- means for making electrical connections to said coils and layers;
- and
- an encapsulating material in the gap between said coils binding said coils together in a fixed relation, with said coils adjusted relative to each other for substantially minimum coupling between the coils.
In a metal detector, the combination of:
- a first coil of rectangular configuration and comprising a plurality of turns of wire encapsulated in an insulating material and having a rectangular opening;
- a first layer of electrical resistive material on said first coil;
- first means for making electrical connections to said first coil and layer;
- a second coil of rectangular configuration and comprising a plurality of turns of wire encapsulated in an insulating material;
- a second layer of electrical resistive material on said second coil;
- second means for making electrical connections to said second coil and layer;
- a frame having top, bottom, two side and two end faces, with a set of screw means carried in each of said faces, with the inner ends of said screw means engaging said first coil in supporting relation;
- and
- coil support means mounted in opposing faces of said frame in engagement with said second coil for supporting said second coil in said opening of said first coil, whereby said coils may be translated and rotated relative to each other to achieve substantially minimum coupling between the coils.
In a nulling fixture for a two coil metal detector, the combination of:
- a frame having top, bottom, two side and two end faces, with a set of screw means carried in each of said faces, with the inner ends of said screw means adapted for engaging a first coil for supporting the coil within the frame;
- and
- a second coil support means mounted in opposing faces of said frame for engaging and supporting a second coil positioned within the first coil, providing for translating and rotating one of the coils relative to the other.
A method of manufacturing an orthogonal coil metal detector, including the steps of:
- applying an electrical resistive layer to a first rectangular encapsulated coil;
- applying an electrical resistive layer to a second rectangular encapsulated coil;
- positioning the second coil within the first coil with an air gap therebetween;
- connecting the layers together at a point remote from the coils;
- connecting an a-c source to one of the coils and detecting the a-c signal produced in the other coil;
- rotating and translating the coils relative to each other to obtain a minimum signal from said other coil;
- filling the gap between the coils with an encapsulating material;
- and
- curing the material in the gap to bond the coils together.
Dependencies are inferred from the claim text.