Pallet jack antenna for RFID system

• US 20060255949A1
• 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 7,557,714 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 an antenna for reading RFID tags in a material handling environment. At least one ruggedized, upward-looking antenna is mounted on the fork (or other base-level platform) of a pallet jack or pallet truck. The antenna can be configured to read RFID tags on pallets that are loaded on the pallet jack 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 suitable for mounting on the fork of a pallet jack, comprising:

a pallet jack fork, said pallet jack fork including a top surface, a first cut-out in said top surface, and two side surfaces, wherein said top and side surfaces form an internal channel;

an antenna mounted in said internal channel, said antenna comprising a radiating element and a power distribution network;

a cover mounted in said cut-out essentially flush with said top surface, so as to permit said radiating element to project a first radio frequency signal from said cut-out in an essentially upward direction.

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

3. 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.

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

5. The antenna system of claim 1, wherein a combined thickness of the antenna and cover is no more than a height of said side surfaces.

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

7. The antenna system of claim 1, wherein said projected first radio frequency signal is circularly polarized.

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

a second cut-out in said top surface;

a second antenna mounted in said internal channel, said second antenna comprising a second radiating element;

a second cover mounted in said second cut-out essentially flush with said top surface, so as to permit said second radiating element to project a second radio frequency signal from said second cut-out in an essentially upward direction.

9. The antenna system of claim 8, wherein said pallet jack fork is configured to hold a first pallet essentially adjacent to a second pallet and said first cut-out and said second cut-out are spaced apart on said top surface so that said first radio frequency signal is projected from under the first pallet and said second radio frequency signal is projected from under the second pallet.

10. The antenna system of claim 8, wherein said first radio frequency signal and said second radio frequency signal are independently controlled by a RFID reader.

11. The antenna system of claim 1, further comprising a RFID reader mounted on said pallet jack and operatively connected to said antenna.

12. The antenna system of claim 1, wherein said antenna is a patch antenna and said patch antenna further comprises a support structure for said radiating element.

13. The antenna system of claim 12, wherein said cover serves as said support structure.

14. The antenna system of claim 12, further comprising a second radiating element operatively coupled to said radio frequency transmission line to form an array.

15. The antenna system of claim 1, wherein said antenna is a slot antenna, said cut-out being in the form of a slot and said pallet jack fork being made of conducting material having a substantially uniform voltage distribution across the fork surface at a low frequency.

16. The antenna system of claim 15, further comprising a second cut-out in the form of a slot, said second cut-out oriented so as to be non-parallel to said first cut-out.

17. The antenna system of claim 16, wherein said first cut-out and said second cut-out are oriented at a 90 degree angle respective to each other.

18. The antenna system of claim 1, wherein said antenna is a leaky waveguide antenna, said antenna further comprising a waveguide channel with said cut-out providing an opening for said waveguide channel.

19. The antenna system of claim 1, wherein said antenna is one or more of a patch antenna, a slot antenna, and a leaky waveguide antenna.

20. A method of collecting inventory tracking data in material handling environment using an integrated pallet jack fork antenna, said method comprising the steps of:

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

transmitting an RF signal from an antenna on the pallet jack fork; and

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

21. The method of claim 20, further comprising the step of communicating the RFID tag information to an inventory management system.

22. The method of claim 20, wherein the radio frequency signal is in the functional range of about 800 to 1000 MHz.

23. The method of claim 20, wherein the radio frequency signal is in the functional range of about 2.4 to 2.5 GHz.

24. The method of claim 20, wherein the RF signal is transmitted from the antenna in a predominantly upward direction.

25. The method of claim 20, wherein said antenna has circular polarization.

26. The method of claim 20, wherein a plurality of antennas are located on the pallet jack and 1 to N pallets are provided and each of said 1 to N pallets is uniquely identified by one or more of said antennas.

27. An antenna system for interrogating radio frequency identification (RFID) tags with backscatter coupling techniques, said antenna suitable for mounting on the fork of a pallet jack, comprising:

a pallet jack fork, said pallet jack fork including a top surface, a two or more cut-outs in said top surface, and two side surfaces, wherein said top and side surfaces from an internal channel;

an antenna mounted in said internal channel at each cut-out, each of said antennas comprising a radiating element and a power distribution network;

a cover mounted in each of said cut-outs, said cover being essentially flush with said top surface, so as to permit each of said antennas to project a radio frequency signal from said cut-out in an essentially upward direction.

28. The antenna system of claim 27, wherein said pallet jack fork is of a length sufficient to accommodate two or more adjacent pallets and wherein each of said antennas is essentially aligned under one pallet.

29. The antenna system of claim 28, wherein each of said antennas communicate independently with a RFID reader.