Self-dispensing spaced electronic markers

• US 5,017,415 A
• Filed: 09/18/1989
• Issued: 05/21/1991
• Est. Priority Date: 09/18/1989
• Status: Expired due to Fees

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Minarovic, Joe T., Cosman, Armond D., Knippelmier, Gary H.
• Primary Examiner(s): Thomas, Alexander S.
• Application Number:
  US07/409,523
• Time in Patent Office: 610 Days
• Field of Search: 428/77, 428/136, 428/99, 428/906, 405/157, 324/326, 324/67
• US Class Current: 428/77
• CPC Class Codes: F16L 1/11 for the detection or protection of pipes in the ground
• CPC Class Codes: G01V 15/00 Tags attached to, or associated with, an object, in order to enable detection of the object record carriers for use with machines having a detectable tag or marker G06K19/00
• CPC Class Codes: G02B 6/562 locatable, e.g. using magnetic means
• CPC Class Codes: Y10S 428/906 Roll or coil
• CPC Class Codes: Y10T 428/24008 including fastener for attaching to external surface
• CPC Class Codes: Y10T 428/24314 Slit or elongated
• CPC Class Codes: Y10T 428/24322 Composite web or sheet

Abstract

A marker tape for location of a buried conduit, having a plurality of electronic markers spaced thereon at predetermined intervals. The distance between the markers encodes information about the buried conduit. The tape may be a nonconductive ribbon or cord, and the markers are preferably passive circuits tuned to a specific frequency. The tape ribbon embodiment may include slots therein for receiving the markers. The markers may be oriented in a predetermined pattern to encode additional information.

Claims

1. An article for electronically marking a buried conduit, comprising:

a plurality of generally cylindrical, electronic markers;

a cord maintaining spacing of said markers at predetermined intervals; and

means attached said markers to said cord.

2. The article of claim 1 wherein said electronic markers are passive, having a coil of wire connected in parallel with a capacitor, forming a resonant circuit.

3. The article of claim 1 wherein said plurality of electronic markers includes a set of first markers having a first resonant frequency, and a set of second markers having a second resonant frequency which is different from said first resonant frequency, said first and second markers being arranged in a predetermined order.

4. An article for electronically marking a buried conduit, comprising:

a plurality of electronic markers having longitudinal axes;

a tape ribbon having a plurality of slots therein receiving said markers and maintaining said markers with their respective axes oriented in a predetermined pattern; and

means attached said markers to said tape ribbon.

5. The article of claim 4 wherein said tape ribbon further spaces said markers at predetermined intervals.

6. The article of claim 4 wherein said plurality of electronic markers includes a set of first markers having a first resonant frequency, and a set of second markers having a second resonant frequency which is different from said first resonant frequency, said first and second markers being arranged in a predetermined order.

7. An article for electronically marking a buried conduit, comprising:

a plurality of first electronic markers each being tuned to a first resonant frequency;

a plurality of second electronic markers each being tuned to a second resonant frequency which is different from said first resonant frequency;

tether means for securing said first and second markers in a predetermined order; and

means for attaching said first and second markers to said tether means.

8. The article of claim 7 wherein said first and second markers are passive, each having a coil of wire connected in parallel with a capacitor.

9. The article of claim 7 wherein said first and second markers have longitudinal axes, said axes being oriented in a predetermined pattern.

10. The article of claim 7 wherein said tether means additionally maintains a spacing of said first and second markers at predetermined intervals.