US3753185A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metal detector search coil
Assignee: Individual
•
Filing: 1972-12-05
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Granted: 1973-08-14
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Expires: 1992-12-05
Abstract
Abstract A device for detecting metal articles buried beneath the surface for example, includes a search coil at one end of a handle, with the handle carrying the detector circuit components. The search coil is an induction coil enclosed within an annular chamber formed from a plastic housing having the form of a spoked wheel for example, and which is formed from two mating housing halves joined in the plane of the coil chamber. The coil is made up of a number of turns of insulated wire wherein the insulation material has a low coefficient of thermal expansion, with the coil being sheathed in metal foil to provide a Faraday shield. The coil is supported within the housing annular chamber on pads of foam rubber-like material which yieldingly supports and restrains the coil within the housing annular chamber.
Inventors
- 👤 W Mahan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:34
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/15
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
110 words
For use with a metal detector, a search coil structure comprising a flat housing defining an annular chamber having bottom and top walls; an induction coil, formed from a plurality of turns of insulated wire, disposed within said housing annular chamber; a sheath enclosing said induction coil turns to form an annular coil unit; cushioning support pads disposed within said housing chamber contiguous to the bottom and top walls respectively; said support pads confronting each other, with the confronting faces being spaced a distance less than the diameter of said sheathed coil unit; and said coil unit being supported between said pads in spaced relation to the housing chamber walls.
Claim 2
Dependent Claim
110 words
For use with a metal detector, a search coil structure comprising a flat housing defining an annular chamber having bottom and top walls; an induction coil, formed from a plurality of turns of insulated wire, disposed within said housing annular chamber; a sheath enclosing said induction coil turns to form an annular coil unit; cushioning support pads disposed within said housing chamber contiguous to the bottom and top walls respectively; said support pads confronting each other, with the confronting faces being spaced a distance less than the diameter of said sheathed coil unit; and said coil unit being supported between said pads in spaced relation to the housing chamber walls.
Claim 3
Dependent Claim
21 words
The search coil structure set forth in claim 1 said sheath being fabricated of metal foil to define a Faraday sHield.
Claim 4
Dependent Claim
20 words
The search coil structure set forth in claim 1 said support pads being annular and coextensive with said chamber walls.
Claim 5
Dependent Claim
33 words
The search coil structure set forth in claim 1 said housing being formed of mating members adjoined in the plane of said annular chamber; said housing members being fabricated from a plastic material.
Claim 6
Dependent Claim
63 words
The search coil structure set forth in claim 2 said housing providing support means adjacent to the center thereof and a radial channel for enclosing the induction coil lead wires; a coaxial connector mounted on said housing radial channel adjacent to the center thereof for connection to said lead wires; and a metal foil sheath enclosing said lead wires in said radial channel.
Claim 7
Dependent Claim
36 words
The search coil structure set forth in claim 1 said housing having the form of a spoked wheel having a rim portion defining said annular chamber; and having a hub portion for securing a supporting handle.
Claim 8
Dependent Claim
20 words
The search coil structure set forth in claim 1 said support pads being fabricated of a foam rubber type material.
Claim 9
Dependent Claim
31 words
The search coil structure set forth in claim 1 said induction coil turns being formed from wire having an insulation fabricated from a material having a low coefficient of thermal expansion.
Claim 10
Dependent Claim
29 words
The search coil structure set forth in claim 1 said induction coil turns being formed from wire having insulation fabricated from a material which remains firm at ambient temperatures.
Claim 11
Dependent Claim
16 words
The search coil structure set forth in claim 1 said wire insulation being fabricated from tetrafluroethylene.
Claim 12
Dependent Claim
16 words
The search coil structure set forth in claim 1 said wire insulation being fabricated from asbestos.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |