Tine-mounted antenna for a RFID

• US 20060255950A1
• Filed: 05/15/2006
• Published: 11/16/2006
• Est. Priority Date: 05/13/2005
• Status: Active Grant

• Current Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Original Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Inventors: Sorenson, Richard W. Jr., Roeder, William H., Runyon, Donald L., Clott, Michael Sayre
• Granted Patent: US 7,548,166 B2
• Time in Patent Office: Days
• US Class Current: 340/572.700
• CPC Class Codes: B62B 3/06 for simply clearing the load from the ground masted lift trucks B66F
• CPC Class Codes: B62B 5/0096 Identification of the cart or merchandise, e.g. by barcodes or radio frequency identification [RFID]
• CPC Class Codes: B66F 9/0755 Position control; Position detectors
• CPC Class Codes: B66F 9/12 Platforms; Forks; Other load supporting or gripping members
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 13/22 Longitudinal slot in boundary wall of waveguide or transmission line H01Q13/203 takes precedence
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence

Abstract

The present invention provides a tine-mounted antenna for reading RFID tags in a warehouse environment using RFID technology operating at ultra-high frequencies (UHF) or microwave frequencies and backscatter coupling techniques. At least one ruggedized antenna is mounted on the tine (or other base-level platform) of a lift truck (e.g., a forklift). The antenna can be configured to read RFID tags on pallets that are loaded on the lift truck and communicate the tag information to a warehouse management system.

Claims

1. An antenna system for interrogating radio frequency identification (RFID) tags with backscatter coupling techniques, said antenna system suitable for mounting on the tine of a forklift, comprising:

a support structure adapted for mounting on said tine, said support structure including a mounting section and a component section each extending along at least a portion of said support structure, said mounting section configured to secure said support structure to said tine and said component section including at least one cavity wherein said cavity has a first opening;

a first antenna mounted in said transverse cavity, said antenna comprising a first radiating element and a first power distribution network;

a first cover for said radiating element, said first cover mounted to and essentially flush with the component section so as to permit said radiating element to project a first radio frequency signal through said opening.

2. The antenna system of claim 1, wherein said mounting section and said component section are side-by-side when said support structure is mounted on said tine.

3. The antenna system of claim 1, wherein said component section is above said mounting section when said support structure is mounted on said tine.

4. The antenna system of claim 1, wherein the first radio frequency signal is in the functional range of about 800 to 1000 MHz.

5. The antenna system of claim 1, wherein the first radio frequency signal is in the functional range of about 2.4 to 2.5 GHz.

6. The antenna system of claim 1, wherein the antenna system has an adjustable power level to allow for accurate RFID tag reading in different applications.

7. The antenna system of claim 1, wherein the first cover is an abrasion-resistant and impact-resistant dielectric material.

8. The antenna system of claim 1, wherein said support structure has a uniform voltage across the component section at low frequency.

9. The antenna system of claim 1, further comprising a first RF cable to provide RF energy to the first power distribution network, wherein said component section contains a channel for the RF cable to extend along a portion of the length of the component section.

10. The antenna system of claim 1, wherein said antenna is an open-ended waveguide antenna.

11. The antenna system of claim 1, wherein said first radiating element is formed by said first cavity in said component section.

12. The antenna system of claim 1, wherein said radiating element is F-shaped.

13. The antenna system of claim 1, further comprising:

a second cavity in said component section, wherein said second cavity has a second opening;

a second radiating element of conducting material mounted within said second transverse cavity; and

a second cover for said radiating element, said second cover mounted to and essentially flush with the component section so as to permit said radiating element to project a second radio frequency signal through said second opening.

14. The antenna system of claim 13, further comprising a first RF cable to provide RF energy to the first power distribution network, wherein said component section contains a channel for the RF cable to extend along a portion of the length of the component section.

15. The antenna system of claim 14, further comprising a second RF cable and a second power distribution network coupled to a second antenna.

16. The antenna system of claim 15, wherein said first radio frequency signal and said second radio frequency signal are independently controlled by a RFID reader.

17. The antenna system of claim 15, wherein each antenna has an independently adjustable power level.

18. The antenna system of claim 13, wherein said forklift tine is of a length sufficient to accommodate two or more adjacent pallets and wherein each of said openings is essentially aligned under one pallet.

19. The antenna system of claim 13, wherein said first antenna is an inverted F antenna.

20. The antenna system of claim 13, wherein said first antenna is an open-ended waveguide antenna.

21. A method of collecting inventory tracking data in a material handling environment using an integrated forklift tine antenna, said method comprising the steps of:

providing inventory RFID tags on a pallet and/or inventory on the pallet, wherein the inventory RFID tags represent inventory contents;

transmitting a radio frequncy signal from an antenna mounted on the forklift tine; and

reading information from the inventory RFID tags using backscatter coupling techniques.

22. The method of claim 21, further comprising the step of communicating the RFID tag information to an inventory management system.

23. The method of claim 21, wherein the radio frequency signal is in the functional range of about 800 to 1000 MHz.

24. The method of claim 21, wherein the radio frequency signal is in the functional range of about 2.4 to 2.5 GHz.

25. The method of claim 21, wherein said antenna is configured to radiate a dual linearly polarized signal.

26. The method of claim 21, wherein a plurality of antennas are located on the forklift tine and 1 to N pallets with product RFID tags are provided so that each of said 1 to N pallets is uniquely identified by one or more of said antennas.

27. The method of claim 26, wherein the power level of the antenna system is adjusted to identify a minimum number of product RFID tags.

32. A tine for a forklift, comprising:

a single piece of rigid material having a vertical portion for mounting to a carriage of a forklift, a horizontal portion for engaging a load, and an elbow portion connecting said vertical portion to said horizontal portion, said horizontal portion including top surface, a bottom surface, a first side surface and a second side surface, wherein said first side surface includes a notch;

an antenna housing mounted in said notch, said housing comprising an opening and a radiating element of conducting material, said housing having a uniform voltage at low frequency, wherein said housing is mounted essentially flush with two of said top, bottom, and first side surfaces with said opening exposed along one of said top, bottom, and first side surfaces so as to project a radio frequency signal from said opening.

33. The tine of claim 32, further comprising a cover for said housing, said cover mounted over said opening and essentially flush with one of said top, bottom, and first side surfaces.

34. The tine of claim 32, wherein the radio frequency signal is in the functional range of about 800 to 1000 MHz.

35. The tine of claim 32, wherein the radio frequency signal is in the functional range of about 2.4 to 2.5 GHz.

36. The tine of claim 32, wherein the antenna system has an adjustable power level to allow for accurate RFID tag reading in different applications.

37. The tine of claim 32, further comprising a radio frequency transmission line, wherein said tine includes a groove extending from said elbow to said notch and said transmission line is mounted in said groove and coupled to said radiating element.

38. The tine of claim 32, further comprising a second notch in which to mound a second antenna housing.

39. A method of associating RFID tags on a shipping unit, said method comprising:

providing a pallet with a uniquely identified RFID tag affixed thereto;

providing individual inventory containers, each container with a uniquely identified RFID tag affixed thereto;

building a shipping unit comprising said pallet and said containers;

using a RFID reader with a computer memory to read data from each of said RFID tags on said containers and said pallet;

associating in the computer memory data from each of said pallet and inventory RFID tags.

40. The method of claim 39, further comprising the steps of affixing to said shipping unit a shipping unit RFID tag;

reading data from said shipping unit RFID tag and associating in the computer memory said unit load RFID tag data with said RFID tag data from said containers and said pallet.

41. The method of claim 39, further comprising the step of storing the associated RFID tag data from said containers and said pallet in an inventory control system.

42. The method of claim 41, further comprising the steps of:

after said storing step, reading data from one of said pallet RFID tags or said inventory container RFID tags;

comparing said data from one of said pallet RFID tags or said inventory container RFID tags with said stored data in the inventory control systems; and

identifying other RFID tag data associated with the data from one of said pallet RFID tag or said inventory container RFID tags.