RFID torque sensing tag system for fasteners

• US 9,483,674 B1
• Filed: 03/07/2014
• Issued: 11/01/2016
• Est. Priority Date: 03/07/2014
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Fink, Patrick W., Lin, Gregory Y., Ngo, Phong H., Kennedy, Timothy F.
• Primary Examiner(s): Backer, Firmin
• Assistant Examiner(s): Tun, Nay
• Application Number:
  US14/200,122
• Time in Patent Office: 970 Days
• US Class Current: 1/1
• CPC Class Codes: F16B 31/028 with a load-indicating washer or washer assembly
• CPC Class Codes: G01L 5/243 using washers
• CPC Class Codes: G06K 7/10366 the interrogation device being adapted for miscellaneous applications

Abstract

The present invention provides an RFID-based torque sensor that can be used to quickly monitor off the shelf fasteners including fasteners that are used in expensive satellites or other uses where fastener failure can be very costly. In one embodiment, an antenna, RFID ring and spring comprise a sensor tag that can be interrogated with an interrogation signal produced by an interrogator device. When sufficient torque is applied to the fastener, an RFID circuit is connected, and produces a radio frequency (RF) signal that can be read by the interrogator. In one embodiment, the RFID circuit does not transmit when the spring member is not compressed, thereby indicating insufficient tensioning of the fastener. The present invention offers the ability to remotely, quickly, and inexpensively verify that any number of fasteners are torqued properly upon initial installation. Where applicable, the present invention allows low cost monitoring over the life of the fastener.

Claims

1. A wireless tag system configured to detect tension of at least one fastener in response to an interrogation signal from a wireless interrogator, comprising:

at least one wireless tag, wherein each of said at least one wireless tag comprises;

a ring circuit comprising two electrical contacts forming a contact gap between said two electrical contacts; and

a first RFID integrated circuit electrically connected in series with said ring circuit,

wherein said each of said at least one wireless tag is operable to transmit a tension indication signal when said contact gap is electrically closed; and

at least one resilient member each comprising a first opening for receiving a corresponding said at least one fastener,

wherein each of said at least one resilient member is responsive to a predetermined amount of tension applied to said corresponding said at least one fastener for movement from an uncompressed first configuration to a compressed second configuration,

wherein in said compressed second configuration, said each of said at least one resilient member indicates said predetermined amount of tension applied to said corresponding said at least one fastener, and

wherein in said compressed second configuration, said each of said at least one resilient member electrically closes a predetermined said ring circuit comprised of a predetermined said contact gap formed by a predetermined said two electrical contacts thereby enabling a predetermined said first RFID integrated circuit to respond to said interrogation signal and a predetermined said at least one wireless tag to transmit a corresponding said tension indication signal.

2. The system of claim 1,

wherein in said uncompressed first configuration, said each of said at least one resilient member comprises an offset between itself and said predetermined said contact gap of said predetermined said ring circuit, and

wherein in said compressed second configuration, said offset is eliminated.

3. The system of claim 1,

wherein said at least one fastener is comprised of one fastener,

wherein said at least one wireless tag is comprised of one wireless tag,

wherein said at least one resilient member is comprised of one resilient member, and

further comprising an antenna operable for transmitting said tension indication signal at a predetermined frequency of operation wherein said antenna is comprised of:

a around metallization layer comprising a first and second distal end and a second opening for receiving said one fastener;

an insulating substrate comprising a third opening for receiving said one fastener wherein said insulating substrate is positioned on top of said ground metallization layer and wherein said second and third openings are substantially aligned with respect to each other;

a first surface metallization layer positioned in proximate relation to said one fastener and on top of a first portion of said insulating substrate; and

a second surface metallization layer positioned in proximate relation to said one fastener, positioned on top of a second portion of said insulating substrate, and positioned in opposite spatial relation to said first surface metallization layer with respect to said one fastener,

wherein said insulating substrate is sandwiched between said ground metallization layer and a combination of said first and second surface metallization layers,

wherein said first surface metallization layer is shorted to said first distal end of said ground metallization layer, and

wherein said second surface metallization layer is shorted to said second distal end of said ground metallization layer.

4. The system of claim 3,

wherein said ring circuit is electromagnetically coupled to said first and second surface metallization layers and said antenna is thereby further comprised of said ring circuit, and

when said one resilient member is in said compressed second configuration,

said one resilient member makes contact with said contact gap of said ring circuit thereby electrically coupling said one resilient member to said first and second surface metallization layers,

said antenna is thereby further comprised of said one resilient member, and

said antenna continues to operate at said predetermined frequency of operation.

5. The system of claim 4,

wherein said one wireless tag is further comprised of a supplemental circuit which is comprised of a second RFID integrated circuit and operable to produce a second wireless signal with identification information in response to said interrogation signal when said one resilient member is in either said uncompressed first configuration or said compressed second configuration,

wherein said ring circuit and said supplemental circuit are in parallel relation to each other, and

wherein said antenna transmits said second wireless signal at said predetermined frequency of operation (a) in response to said interrogation signal and (b) when said one resilient member is in either said uncompressed first configuration or said compressed second configuration.

6. The system of claim 5, further comprising software operable to analyze said second wireless signal as a means for determining if said interrogation signal is adequate for receiving said tension indication signal.

7. The system of claim 3, wherein said ring circuit is electromagnetically coupled to said first and second surface metallization layers and said antenna is thereby further comprised of said ring circuit.

8. The system of claim 1, wherein said each of said at least one wireless tag further comprises:

a supplemental circuit comprising a second RFID integrated circuit and operable to produce a second wireless signal with identification information in response to said interrogation signal when at least one corresponding said at least one resilient member is in either said uncompressed first configuration or said compressed second configuration.

9. The system of claim 8, further comprising software operable to analyze said second wireless signal as a means for determining if said interrogation signal is adequate for receiving said tension indication signal.

10. A wireless tag system configured to detect a tension applied to a fastener in response to an interrogation signal from a wireless interrogator, comprising:

a resilient member comprising a first opening for receiving said fastener wherein said resilient member is capable of compressing in a predetermined compressed configuration in response to said tension applied to said fastener;

a wireless tag controllably operable to transmit a tension indication signal indicating said tension applied to said fastener in response to said resilient member in said predetermined compressed configuration; and

an antenna operably connected to said wireless tag and operable to transmit said tension indication signal to said wireless interrogator at a predetermined frequency of operation, said antenna comprising;

a ground metallization layer comprising a first and second distal end and a second opening for receiving said fastener;

an insulating substrate comprising a third opening for receiving said fastener wherein said insulating substrate is positioned on top of said ground metallization layer and wherein said first, second, and third openings are substantially aligned with respect to each other;

a first surface metallization layer positioned in proximate relation to said fastener and on top of a first portion of said insulating substrate; and

a second surface metallization layer positioned in proximate relation to said fastener, positioned on top of a second portion of said insulating substrate, and positioned in opposite spatial relation to said first surface metallization layer with respect to said fastener,

wherein said insulating substrate is sandwiched between said ground metallization layer and a combination of said first and second surface metallization layers,

wherein said first surface metallization layer is electrically connected to said first distal end of said round metallization layer, and

wherein said second surface metallization layer is electrically connected to said second distal end of said ground metallization layer.

11. The system of claim 10, wherein said wireless tag is configured to exclusively utilize power of said interrogation signal and wherein said interrogation signal provides si power for said wireless tag to wirelessly transmit said tension indication signal.

12. The system of claim 10, wherein said wireless tag is comprised of:

a ring circuit comprising two electrical contacts forming a contact gap between said two electrical contacts; and

a first RFID integrated circuit electrically connected in series with said ring circuit, wherein said contact gap of said ring circuit is electrically closed when said resilient member is in said predetermined compressed configuration.

13. The system of claim 12,

wherein said ring circuit is electromagnetically coupled to said first and second surface metallization layers and said antenna is thereby further comprised of said ring circuit, and

when said resilient member is in said predetermined compressed configuration,

said resilient member makes contact with said contact gap of said ring circuit thereby electrically coupling said resilient member to said first and second surface metallization layers, and

said antenna is thereby further comprised of said resilient member.

14. The system of claim 13, wherein said antenna is operable to transmit said tension indication signal at said predetermined frequency of operation.

15. The system of claim 12, wherein said wireless tag is further comprised of:

a supplemental circuit comprising a second RFID integrated circuit and operable to transmit a second wireless signal with identification information when said resilient member is either in or not in said predetermined compressed configuration.

16. The system of claim 15,

wherein said supplemental circuit is operable to transmit said second wireless signal with said identification information when said resilient member is only in said predetermined compressed configuration.

17. The system of claim 15, further comprising software operable to analyze said second wireless signal as a means for determining if said interrogation signal is adequate for receiving said tension indication signal.

18. The system of claim 15, wherein said ring circuit and said supplemental circuit are in parallel relation to each other.

19. The system of claim 12,

wherein said ring circuit is electromagnetically coupled to said first and second surface metallization layers and said antenna is thereby further comprised of said ring circuit.

20. The system of claim 19, wherein said antenna is operable to transmit said tension indication signal at said predetermined frequency of operation.