US5114517A
Expired / Lapsed
US
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Methods, apparatus and devices relating to magnetic markers for elongated hidden objects
Assignee: Schonstedt Instrument Co LLC
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Filing: 1990-02-09
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Granted: 1992-05-19
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Expires: 2010-02-09
Abstract
Abstract A magnetic marker serving to locate, trace, and identify an elongated hidden object, such as a buried utility pipe, duct, conduit, or fiber optic cable, is manufactured by applying magnetic material to a substrate that is elongated and by forming from the material a helical or twisted permanent magnet pattern extending along the length of the substrate. The magnetic material, which may be coextensive with the substrate or applied to a portion only of the substrate, may be formed as a strip coextruded with the substrate and magnetized in the direction of the width of the strip. Alternatively, magnetic material may be mixed with the material from which the substrate is extruded or may be coated on the substrate. A strip may also be preformed and applied to an elongated object as the object is buried, or the strip may form a separate warning tape that is buried with the object and that is provided with a desired magnetic signature by twisting the strip lengthwise as it is advanced for burial.
Inventors
- 👤 John B. Rippingale
- 👤 Erick O. Schonstedt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:10
CPC Classifications
F; F16; F16L; F16L1/00; F16L1/024; F16L1/06; F16L1/11; B; B29; B29C; B29C48/00; B29C48/001; B29C48/0013; B29C48/0015; B29C48/0016; B29C48/03; B29C48/09; B29C48/16; B29C48/18; B29C48/21; G; G01; G01V; G01V15/00; G01V3/00; G01V3/15; G02; G02B; G02B6/00; G02B6/46; G02B6/56; G02B6/562; B29C48/05; B29K; B29K2995/00; B29K2995/0003; B29L; B29L2011/00; B29L2011/0075; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49071; Y10T29/49075; Y10T29/49078
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
62 words
A method of making a magnetic marker, comprising applying magnetic material to a substrate that is elongated, and forming at least a portion of said material into a helical permanent magnet pattern having a helix axis extending along the length, of said substrate, and wherein said forming of said helical magnetic pattern includes permanently magnetizing at least said portion of said material.
Claim 2
Independent Claim
62 words
A method of making a magnetic marker, comprising applying magnetic material to a substrate that is elongated, and forming at least a portion of said material into a helical permanent magnet pattern having a helix axis extending along the length, of said substrate, and wherein said forming of said helical magnetic pattern includes permanently magnetizing at least said portion of said material.
Claim 3
Dependent Claim
77 words
A method in accordance with claim 1, wherein said magnetic material is applied so as to be substantially coextensive with said substrate, and said forming comprises subjecting at least said portion of said magnetic material to a magnetic field transverse to said substrate and providing relative movement between said magnetic field and said substrate, wherein the relative movement includes relative rotational movement around the length of said substrate and relative movement along the length of said substrate.
Claim 4
Dependent Claim
20 words
A method in accordance with claim 1, wherein said magnetic material is applied to a portion only of said substrate.
Claim 5
Dependent Claim
24 words
A method in accordance with claim 1, wherein said pattern is formed by a helical strip permanently magnetized in the direction of its width.
Claim 6
Dependent Claim
16 words
A method in accordance with claim 1, wherein said substrate is formed as an extruded tube.
Claim 7
Dependent Claim
21 words
A method in accordance with claim 5, wherein said magnetic material is applied to said substrate by coextrusion with said tube.
Claim 8
Dependent Claim
29 words
A method in accordance with claim 5, wherein said magnetic material is applied to said substrate by mixing the magnetic material with material from which said tube is extruded.
Claim 9
Dependent Claim
54 words
A method in accordance with claim 1, wherein said substrate is formed as a cylinder that is advanced along its length and wherein said magnetic material is applied to said substrate from an extruder die having an outlet that rotates about the axis of said cylinder as the cylinder is advanced along its length.
Claim 10
Dependent Claim
33 words
A method in accordance with claim 8, wherein said magnetic material is magnetized by a magnetic field that rotates about the axis of said cylinder in synchronism with the rotation of said die.
Claim 11
Dependent Claim
95 words
A method in accordance with claim 1, wherein said substrate is formed as an extruded cylinder that advances along its length and that is taken up by rotation of a take-up spool about a winding axis, wherein said magnetic material is applied to said cylinder as a strip extending substantially parallel to the length of the cylinder as the cylinder is extruded, and wherein the strip is thereafter formed into a helix by rotating the take-up spool about an axis substantially perpendicular to said winding axis and substantially parallel to the length of said cylinder.
Claim 12
Dependent Claim
15 words
A method in accordance with claim 1, wherein said substrate is formed as a duct.
Claim 13
Dependent Claim
20 words
A method in accordance with claim 11, wherein a cable is inserted into said duct as the duct is formed.
Claim 14
Dependent Claim
65 words
Apparatus for making a magnetic marker, comprising means for providing a substrate that is elongated, means for applying magnetic material to said substrate, and means for forming at least a portion of said material into a helical permanent magnet pattern having a helix axis extending along the length of said substrate, and wherein said forming means permanently magnetizes at least said portion of magnetic material.
Claim 15
Dependent Claim
65 words
Apparatus for making a magnetic marker, comprising means for providing a substrate that is elongated, means for applying magnetic material to said substrate, and means for forming at least a portion of said material into a helical permanent magnet pattern having a helix axis extending along the length of said substrate, and wherein said forming means permanently magnetizes at least said portion of magnetic material.
Claim 16
Dependent Claim
23 words
Apparatus in accordance with claim 13, wherein said applying means applies said magnetic material so as to be substantially coextensive with said substrate.
Claim 17
Dependent Claim
21 words
Apparatus in accordance with claim 13, wherein said applying means applies said magnetic material to a portion only of said substrate.
Claim 18
Dependent Claim
25 words
Apparatus in accordance with claim 13, wherein said forming means forms said pattern as a helical strip permanently magnetized in the direction of its width.
Claim 19
Dependent Claim
60 words
Apparatus for making a magnetic marker, comprising means for providing a substrate that is elongated, means for applying magnetic material to said substrate, and means for forming from said material a helical permanent magnet pattern having a helix axis extending along the length of said substrate, wherein said providing means provides said substrate in the form of an extruded tube.
Claim 20
Dependent Claim
60 words
Apparatus for making a magnetic marker, comprising means for providing a substrate that is elongated, means for applying magnetic material to said substrate, and means for forming from said material a helical permanent magnet pattern having a helix axis extending along the length of said substrate, wherein said providing means provides said substrate in the form of an extruded tube.
Claim 21
Dependent Claim
20 words
Apparatus in accordance with claim 17, wherein said applying means comprises means for coextruding said magnetic material with said tube.
Claim 22
Dependent Claim
26 words
Apparatus in accordance with claim 17, wherein said applying means comprises means for applying said magnetic material mixed with material from which said tube is extruded.
Claim 23
Dependent Claim
103 words
Apparatus for making a magnetic marker, comprising means for providing a substrate that is elongated, means for applying magnetic material to said substrate, and means for forming said material a helical permanent magnet pattern having a helix axis extending along the length of said substrate, wherein said providing means comprises means for forming said substrate as a cylinder that is advanced along its length, and wherein said applying means comprises an extruder die having an outlet that rotates about the axis of said cylinder as the cylinder is advanced along its length, said magnetic material being applied to said cylinder from said outlet.
Claim 24
Dependent Claim
103 words
Apparatus for making a magnetic marker, comprising means for providing a substrate that is elongated, means for applying magnetic material to said substrate, and means for forming said material a helical permanent magnet pattern having a helix axis extending along the length of said substrate, wherein said providing means comprises means for forming said substrate as a cylinder that is advanced along its length, and wherein said applying means comprises an extruder die having an outlet that rotates about the axis of said cylinder as the cylinder is advanced along its length, said magnetic material being applied to said cylinder from said outlet.
Claim 25
Dependent Claim
37 words
Apparatus in accordance with claim 20, wherein said forming means comprises means for magnetizing said magnetic material with a magnetic field that rotates about the axis of said cylinder in synchronism with the rotation of said die.
Claim 26
Dependent Claim
137 words
Apparatus for making a magnetic marker, comprising means for providing a substrate that is elongated, means for applying magnetic material to said substrate, and means for forming from said material a helical permanent magnet pattern having a helix axis extending along the length of said substrate, wherein said providing means comprises means for extruding said substrate as a cylinder that advances along its length and a take-up spool that rotates about a winding axis for winding the cylinder thereon, wherein said applying means applies said magnetic material to said cylinder as a strip extending substantially parallel to the axis of the cylinder as the cylinder is extruded, and wherein said forming means comprises means for rotating said take-up spool about an axis substantially perpendicular to said winding axis and substantially parallel to the length of said cylinder.
Claim 27
Dependent Claim
137 words
Apparatus for making a magnetic marker, comprising means for providing a substrate that is elongated, means for applying magnetic material to said substrate, and means for forming from said material a helical permanent magnet pattern having a helix axis extending along the length of said substrate, wherein said providing means comprises means for extruding said substrate as a cylinder that advances along its length and a take-up spool that rotates about a winding axis for winding the cylinder thereon, wherein said applying means applies said magnetic material to said cylinder as a strip extending substantially parallel to the axis of the cylinder as the cylinder is extruded, and wherein said forming means comprises means for rotating said take-up spool about an axis substantially perpendicular to said winding axis and substantially parallel to the length of said cylinder.
Claim 28
Dependent Claim
16 words
Apparatus in accordance with claim 13, wherein said providing means forms said substrate as a duct.
Claim 29
Dependent Claim
21 words
Apparatus in accordance with claim 23, further comprising means for inserting a cable into said duct as the duct is formed.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-05-19 | 1995-11-18 | 1996-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-19 | 1999-11-18 | 2000-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-19 | 2003-11-18 | 2004-05-19 | $7700.00 | Window Closed / Lapsed |