Radio frequency identification systems for asset tracking

• US 20030089771A1
• Filed: 11/12/2001
• Published: 05/15/2003
• Est. Priority Date: 11/12/2001
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Francis, Robert C., Kallestad, Mary C., Tong, Sai-Kit K., Dehn, Francis D., Cybulski, Eric R., Kropp, Karl M., McGee, James P., Hogerton, Peter B.
• Granted Patent: US 6,669,089 B2
• Time in Patent Office: Days
• US Class Current: 235/385
• CPC Class Codes: B65D 19/00 Pallets or like platforms, with or without side walls, for supporting loads to be lifted or lowered in devices for lifting or lowering bulky or heavy goods for loading or unloading purposes B66F9/12
• CPC Class Codes: B65D 2203/10 Transponders
• CPC Class Codes: B66F 9/0755 Position control; Position detectors
• CPC Class Codes: G06K 19/07758 arrangements for adhering the record carrier to further objects or living beings, functioning as an identification tag

Abstract

An asset tracking system is provided, having particular usefulness in connection with the interrogation of RFID-tagged pallets by a forklift equipped with one or more RFID reader antennas. A useful embodiment of an RFID-tagged pallet is described, along with other beneficial components of such a system.

Claims

1. An asset tracking system, comprising:

a) at least one RFID reader antenna positioned on a fixed portion of a forklift;

b) at least one RFID reader antenna positioned on a portion of the forklift that is vertically movable with respect to the fixed portion; and

c) a pallet including at least two RFID tags, in which one RFID tag is positioned in one quadrant of the pallet and another RFID tag is positioned in an opposite quadrant of the pallet, to enable at least one of the RFID tags to be interrogated by an RFID reader antenna adjacent any one of the four sides of the pallet.

2. The system of claim 1, wherein the system comprises at least two substantially horizontally-aligned RFID reader antennas positioned on the vertically movable portion of the forklift, and at least two substantially horizontally-aligned RFID reader antennas positioned on the fixed portion of the forklift.

3. The system of claim 1, wherein the pallet includes only two RFID tags.

4. The system of claim 1, wherein at least one RFID tag has a longitudinal axis positioned at approximately a 45-degree angle with respect to a side of the pallet.

5. The system of claim 1, wherein at least one RFID tag is secured in an opening in the pallet.

6. The system of claim 1, wherein the forklift includes at least one of a sensor to activate an RFID interrogation system automatically, and a deactivation system to turn off the RFID interrogation system automatically if no RFID tag has been successfully interrogated for a predetermined period of time.

7. The system of claim 1, wherein an array of reader antennas are provided, at least two of which are horizontally aligned and at least two of which are vertically aligned.

8. The system of claim 1, in combination with the forklift.

9. The system of claim 1, in combination with a plurality of pallets.

10. The system of claim 9, in combination with a double stack of pallets, wherein the system further comprises one set of RFID reader antennas for reading RFID tags associated with a first stack of pallets, and a second set of RFID reader antennas for reading RFID tags associated with a second stack of pallets.

11. The system of claim 1, wherein the system also comprises an antenna adapted to interrogate location RFID tags to provide information to the system related to a specific location.

12. The system of claim 1, further comprising a multiplexing circuit for multiplexing interrogation signals between the antennas.

13. A pallet, comprising:

(a) a first RFID tag provided in a first quadrant of the pallet; and

(b) a second RFID tag provided in an opposed second quadrant of the pallet, such that an RFID reader antenna that approaches the pallet from one of the four sides of the pallet can interrogate at least one of the RFID tags.

14. The pallet of claim 13, wherein at least one RFID tag has a longitudinal axis positioned at approximately a 45-degree angle with respect to a side of the pallet.

15. The pallet of claim 13, wherein the pallet includes only two RFID tags.

16. The pallet of claim 13, wherein the pallet includes two end boards, each of which includes an RFID tag positioned on or in the end board at approximately a 45-degree angle with respect to the longitudinal axis of the end board.

17. The pallet of claim 16, wherein the end board comprises plastic.

18. The pallet of claim 16, wherein the end board is made of wood.

19. A stack of the pallets of claim 13.

20. The pallet of claim 13, wherein the RFID tag is contained within a hermetically-sealed enclosure.

21. The pallet of claim 20, wherein the hermetically-sealed enclosure is received within an opening in the end board.

22. A forklift RFID system, comprising:

a) at least one RFID antenna positioned on a fixed portion of the forklift; and

b) at least one RFID antenna positioned on a portion of the forklift that is vertically movable with respect to the fixed portion.

23. The forklift RFID system of claim 22, wherein the system comprises at least four spaced antennas on the fixed portion of the forklift, and at least four spaced antennas on the vertically movable portion of the forklift.

24. The forklift RFID system of claim 22, wherein the forklift further comprises an antenna for interrogating RFID location tags in a storage area.

25. The forklift RFID system of claim 24, wherein the antenna for interrogating RFID location tags in a storage area is located on the top of the forklift, and at least one RFID location tag is located in the storage area above that antenna.

26. The forklift RFID system of claim 22, wherein the system further comprises a multiplexing circuit for multiplexing interrogation signals among the at least two antennas.

27. The system of claim 22, wherein the system further comprises a user interface including a touch-panel display.

28. The system of claim 27, wherein the system further comprises software adapted to provide information to the display describing which RFID tags have been interrogated by the antennas.

29. The system of claim 22, wherein the system further comprises software adapted to provide information to a user interface regarding a pallet.

30. The system of claim 29, wherein the software associates an RFID-tagged pallet with an RFID location tag.

31. The system of claim 27, wherein the software provides a signal to user through the user interface when a forklift carrying an RFID-tagged pallet approaches a correct RFID location tag.

32. The system of claim 27, wherein the software provides a signal to a user through the user interface when a forklift carrying an RFID-tagged pallet approaches an incorrect RFID location tag.

33. The system of claim 22, wherein the forklift includes at least one sensor to activate an RFID interrogation system automatically.

34. The system of claim 22, wherein the forklift includes a deactivation system to turn off the RFID interrogation system automatically if no RFID tag has been successfully interrogated for a predetermined period of time.

35. A forklift RFID system, comprising:

(a) a forklift having a mast and a load backrest; and

(b) at least one RFID antenna positioned within a column on each side of the forklift, the columns each being bounded by (i) the outer edge of the forklift mast;

(ii) the outer edge of the forklift, (iii) the back edge of the forklift mast, and (iv) the front edge of the load backrest.

36. The forklift RFID system of claim 35, wherein the system includes at least four RFID antennas, two of which are disposed on each side of the mast.

37. The forklift RFID system of claim 35, wherein the system includes at least eight RFID antennas, four of which are disposed on each side of the mast.

38. The forklift RFID system of claim 35, wherein the system comprises at least one antenna on a fixed portion of the forklift, and at least one antenna on a vertically movable portion of the forklift.

39. The forklift RFID system of claim 35, wherein the forklift further comprises an antenna for interrogating RFID location tags in a storage area.

40. The forklift RFID system of claim 39, wherein the antenna for interrogating RFID location tags in a storage area is located on the top of the forklift, and at least one RFID location tag is located in the storage area above that antenna.

41. The forklift RFID system of claim 35, wherein the system further comprises a multiplexing circuit for multiplexing interrogation signals among the at least two antennas.

42. The system of claim 35, wherein the system further comprises a user interface including a touch-panel display.

43. The system of claim 42, wherein the system further comprises software adapted to provide information to the display describing which RFID tags have been interrogated by the antennas.

44. The system of claim 35, wherein the system further comprises software adapted to provide information to a user interface regarding a pallet.

45. The system of claim 44, wherein the software associates an RFID-tagged pallet with an RFID location tag.

46. The system of claim 44, wherein the software provides a signal to user through the user interface when a forklift carrying an RFID-tagged pallet approaches a correct RFID location tag.

47. The system of claim 44, wherein the software provides a signal to a user through the user interface when a forklift carrying an RFID-tagged pallet approaches an incorrect RFID location tag.

48. The system of claim 35, wherein the forklift includes at least one sensor to activate an RFID interrogation system automatically.

49. The system of claim 35, wherein the forklift includes a deactivation system to turn off the RFID interrogation system automatically if no RFID tag has been successfully interrogated for a predetermined period of time.

50. A board for a pallet, wherein the board includes an edge and an RFID tag positioned at approximately a 45-degree angle with respect to that edge.

51. The board of claim 50, wherein the board is wood.

52. The board of claim 50, wherein the board is plastic.

53. The board of claim 50, wherein the RFID tag is positioned within a slot formed in the board.

54. The board of claim 50, wherein the RFID tag is positioned within an enclosure that is affixed to the board.

55. A pallet including a corner block, wherein the corner block includes a chamfered inside corner with an RFID tag affixed thereto.

56. The pallet of claim 55, wherein the RFID tag has a longitudinal axis that is parallel to the z axis of the pallet.

57. The pallet of claim 55, wherein the pallet includes two corner blocks, and each corner block includes a chamfered inside corner with an RFID tag affixed thereto.