Magnetic vector field tag and seal

• US 6,784,796 B2
• Filed: 11/06/2001
• Issued: 08/31/2004
• Est. Priority Date: 12/17/1999
• Status: Expired due to Fees

• Current Assignee: Los Alamos National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Garcia, Anthony R. E., Johnston, Roger G.
• Primary Examiner(s): Mullen, Thomas J
• Application Number:
  US10/046,100
• Publication Number:
  US 20020171547A1
• Time in Patent Office: 1,029 Days
• Field of Search: 340/568.1, 340/572.1, 340/541, 340/547, 340/545.6, 335/219, 335/209, 600/15, 324/207.11, 324/207.22, 324/207.26, 446/444, 446/446, 446/447, 446/129, 446/131
• US Class Current: 340/568.1
• CPC Class Codes: G08B 13/06 by tampering with fastening
• CPC Class Codes: G08B 13/126 for a housing, e.g. a box, a safe, or a room
• CPC Class Codes: G08B 13/2442 Tag materials and material properties thereof, e.g. magnetic material details

Abstract

One or more magnets are placed in a container (preferably on objects inside the container) and the magnetic field strength and vector direction are measured with a magnetometer from at least one location near the container to provide the container with a magnetic vector field tag and seal. The location(s) of the magnetometer relative to the container are also noted. If the position of any magnet inside the container changes, then the measured vector fields at the these locations also change, indicating that the tag has been removed, the seal has broken, and therefore that the container and objects inside may have been tampered with. A hollow wheel with magnets inside may also provide a similar magnetic vector field tag and seal. As the wheel turns, the magnets tumble randomly inside, removing the tag and breaking the seal.

Claims

1. A method for providing a container that contains one or more objects with a magnetic vector field tag and seal, comprising the steps of:

(a) placing a magnetometer at a first location relative to the container;

(b) placing at least one magnet inside the container, the magnet providing a measurable magnetic field strength and vector direction at the first location of the magnetometer;

(c) measuring the magnetic field strength and vector direction at the first location using the magnetometer to provide the container with a magnetic vector field tag and seal; and

(d) removing the magnetometer.

2. The method of claim 1, wherein the at least one magnet comprises a permanent magnet.

3. The method of claim 1, wherein the at least one magnet comprises an electromagnet.

4. The method of claim 1, wherein the at least one magnet is placed on at least one object in the container.

5. The method of claim 1, wherein the magnetic field strength and vector direction are measured from inside the container.

6. The method of claim 1, wherein the magnetic field strength and vector direction are measured from outside the container.

7. The method of claim 1, further comprising repositioning the at least one magnet by exposing it to a magnetic force, thereby changing the measured magnetic strength and vector direction at the first location, thereafter measuring the new magnetic strength and vector direction at the first location, and thereafter removing the magnetometer.

8. The method of claim 1, wherein the magnet comprises a magnet rotatably engaged to a gimbal.

9. A method of providing a container filled with one or more objects with a magnetic vector field tag and seal, comprising the steps of:

(a) positioning a magnetometer at a first location relative to the container;

(b) placing a plurality of magnets inside the container, the plurality of magnets providing a measurable magnetic field strength and vector direction at the first location of the magnetometer;

(c) measuring the strength and vector direction of the magnetic field at the first location using the magnetometer to provide the container with a magnetic vector field tag and seal; and

(d) removing the magnetometer.

10. The method of claim 9, wherein at least one magnet of the plurality of magnets comprises a permanent magnet.

11. The method of claim 9, wherein at least one magnet of the plurality of magnets comprises an electromagnet.

12. The method of claim 9, wherein at least one of the plurality of magnets is placed on at least one object inside the container.

13. The method of claim 9, wherein the magnetic field strength and vector direction are measured from inside the container.

14. The method of claim 9, wherein the magnetic field strength and vector direction are measured from outside the container.

15. The method of claim 9, further comprising repositioning at least one of the plurality of magnets by exposing the plurality of magnets to a magnetic force, thereby changing the measured magnetic strength and vector direction at the first location, thereafter measuring the new magnetic strength and vector direction at the first location, and thereafter removing the magnetometer.

16. The method of claim 9, wherein at least one of the plurality of magnets comprises a magnet rotatably engaged to a gimbal.

17. A magnetic device, comprising:

(a) a permanent magnet;

(b) a wheel having a chamber sufficiently large for receiving said magnet and allowing it to tumble randomly inside when the wheel rotates about its axis; and

(c) an axle coincident with the wheel axis about which said wheel can rotate.

18. A magnetic device, comprising:

(a) a plurality of permanent magnets;

(b) a wheel having a plurality of chambers, each chamber sufficiently large to receive at least one of the magnets and allow it to tumble randomly inside when the wheel rotates about its axis; and

(c) an axle coincident with the wheel axis about which said wheel can rotate.

19. A movable tray, comprising:

(a) a permanent magnet;

(b) at least three wheels, one of said wheels having a chamber sufficiently large to receive the magnet and allow it to tumble randomly inside when the wheel rotates about its axis;

(c) axles for each wheel, each axle being coincident with the wheel axis about which said wheel can rotate;

(d) a substantially flat support having a first side for supporting objects thereupon and a second side for attaching said wheels thereto such that the support can be rolled across a surface; and

(e) means for attaching said wheels to the support.

20. The tray of claim 19, wherein at least two of said wheels each comprise a chamber large enough to receive a magnet and allow it to tumble randomly when the tray is rolled across a surface, and further comprising at least one additional magnet inside each additional chamber large enough to receive said magnet and allow it to tumble randomly therein.

21. A method for providing a stationary object with a magnetic vector field tag and seal, comprising:

(a) providing a device comprising a plurality of permanent magnets attached to a flexible support that can be wrapped around a stationary object; and

(b) wrapping the device around the object, and measuring the magnetic field strength and vector direction from at least one location near the object.