Strain gauge with moisture barrier

• US 8,490,481 B2
• Filed: 09/17/2008
• Issued: 07/23/2013
• Est. Priority Date: 03/29/2004
• Status: Active Grant

• Current Assignee: Hottinger Bruel & Kjaer Incorporated
• Original Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Inventors: Arms, Steven W., Townsend, Christopher P., Mundell, Steven W., Churchill, David L.
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): ROY, PUNAM P
• Application Number:
  US12/211,975
• Publication Number:
  US 20090007687A1
• Time in Patent Office: 1,770 Days
• Field of Search: 734/31, 737/65, 737/76, 737/86
• US Class Current: 73/431
• CPC Class Codes: G01B 7/16 for measuring the deformation in a solid, e.g. by resistance strain gauge
• CPC Class Codes: G01B 7/20 formed by printed-circuit technique
• CPC Class Codes: G01L 1/2268 Arrangements for correcting or for compensating unwanted effects
• CPC Class Codes: G01L 1/26 Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload
• CPC Class Codes: G01M 5/0083 by measuring variation of impedance, e.g. resistance, capacitance, induction
• CPC Class Codes: G01N 27/223 for determining moisture content, e.g. humidity rain detectors on vehicle windows B60S1/0825
• CPC Class Codes: G01N 33/442 Resins, plastics

Abstract

A device for mounting on a structure surface includes a component, a circuit, a moisture barrier, and a protective cover. The moisture barrier is within the protective cover. The component and the circuit are within the moisture barrier. The component is for bonding to the structure surface with a bond susceptible to damage from moisture. The circuit includes a radio frequency transmitter. The circuit is for providing data derived from the component to the radio frequency transmitter for external transmission.

Claims

1. A method of protecting a strain gauge on a structure surface, comprising:

a. providing a structure, wherein said structure has a structure surface;

b. providing a strain gauge and a preformed protective cover;

c. bonding said strain gauge to said structure surface;

d. placing said preformed protective cover over said strain gauge and connecting said preformed protective cover to said structure surface to enclose said strain gauge within said preformed protective cover, wherein other than at a penetration extending through said protective cover outer surface, all sidewalls of said preformed protective cover at least one from the group consisting of (a) have a rounded convex outer surface, wherein said rounded convex outer surface extends from the structure surface, and (b) are tilted, wherein said tilted sidewalls extend toward each other from the structure surface; and

e. providing an energy providing device, wherein said energy providing device includes a battery, said battery being replaceably sealed within said protective cover. measured by said temperature sensor.

2. A method as recited in claim 1, wherein said structure includes at least one from the group consisting of a building, a bridge, a vehicle, construction equipment, and excavation machinery.

3. A method as recited in claim 1, wherein said structure includes one from the group consisting of a car, a truck, and a ship.

4. A method as recited in claim 1, wherein no wires exit said Preformed protective cover.

5. A method as recited in claim 4, wherein said spinning shaft is part of at least one from the group consisting of a motor, a pump, and a generator.

6. A method as recited in claim 1, wherein said preformed protective cover is fabricated of polycarbonate.

7. A method as recited in claim 1, wherein no wires exit said preformed protective cover.

8. A method as recited in claim 1, wherein said bonding said strain gauge includes providing a light curable adhesive, positioning said strain gauge on said structure with said light curable adhesive, and exposing said light curable adhesive to light.

9. A method as recited in claim 8, wherein said light curable adhesive is UV light curable, wherein said exposing said light curable adhesive to light involves exposing said UV light curable adhesive to UV light.

10. A method as recited in claim 1, further comprising providing a microprocessor and signal conditioning.

11. A method as recited in claim 1, wherein said seal includes an o-ring.

12. A method as recited in claim 1, wherein said energy providing device includes an energy harvesting device.

13. A method as recited in claim 1, wherein said connecting said preformed protective cover to said structure surface includes adhesively bonding said preformed protective cover to said structure surface.

14. A method as recited in claim 13, wherein said preformed protective cover includes adhesive tape, wherein said adhesively bonding said preformed protective cover to said structure surface includes bonding with said adhesive tape.

15. A method as recited in claim 1, wherein said structure includes a civil structure.

16. A method as recited in claim 1, wherein said structure includes a machine.

17. A method as recited in claim 1, further comprising providing a moisture barrier material within said preformed protective cover.

18. A method as recited in claim 17, wherein said moisture barrier material includes a wax material.

19. A method as recited in claim 18, wherein said wax material includes at least one from the group consisting of wax, grease, a foam, and Waxoyl.

20. A method as recited in claim 17, wherein said providing said moisture barrier material within said preformed protective cover includes substantially filling said protective cover.

21. A method as recited in claim 17, wherein said providing said moisture barrier material within said preformed protective cover includes providing a thin layer on said strain gauge.

22. A method as recited in claim 17, wherein said preformed protective cover has a mechanical strength sufficient to protect said moisture barrier from mechanical damage.

23. A method as recited in claim 17, wherein said protective cover includes a first port for filling said protective cover with said moisture barrier and a second port for providing an exhaust while filling, wherein said moisture barrier material is provided after said connecting said preformed protective cover to said structure surface, further comprising injecting said moisture barrier into said first port in said protective cover and filling said protective cover with said moisture barrier.

24. A method as recited in claim 1, wherein said structure surface is subject to strain from a mechanical force other than that provided by bonding said strain gauge to said structure surface, wherein said bonding said strain gauge to said structure surface is for obtaining data related to said strain from said mechanical force, further comprising obtaining said data related to said strain from said mechanical force.

25. A method as recited in claim 24, further comprising providing a processor, a memory, a wireless communications device, and a power supply within said protective cover, wherein said obtaining said data related to said strain from said mechanical force involves transmitting with said wireless communications device.

26. A method as recited in claim 25, further comprising logging said data related to said strain from said mechanical force in said memory.

27. A method as recited in claim 25, further comprising providing a temperature sensor within said protective cover and obtaining data related to temperature measured by said temperature sensor.

28. A method of protecting a strain gauge on a structure surface, comprising:

a. providing a structure, wherein said structure has a structure surface;

b. providing a strain gauge, a wireless communications device, a moisture barrier material, and a preformed protective cover, wherein said wireless communications device is connected for transmitting data derived from said strain gauge for external transmission, wherein said preformed protective cover includes a first port for filling said preformed protective cover with said moisture barrier material;

c. bonding said strain gauge to said structure surface with a bond, wherein said bond is susceptible to damage from moisture;

d. placing said preformed protective cover over said strain gauge and over said wireless communications device and connecting said preformed protective cover to said structure surface to enclose said strain gauge and said wireless communications device within said preformed protective cover;

e. after said connecting said preformed protective cover to said structure surface providing said moisture barrier material within said preformed protective cover by injecting said moisture barrier into said first port in said protective cover and filling said protective cover with said moisture barrier material.

29. A method as recited in claim 28, wherein said preformed protective cover has an outer surface having a convex curvature, said convex curvature extends from said structure.

30. A method as recited in claim 28, wherein said structure surface is subject to strain from a mechanical force other than that provided by bonding said strain gauge to said structure surface, wherein said bonding said strain gauge to said structure surface is for obtaining data related to said strain from said mechanical force, further comprising obtaining said data related to said strain from said mechanical force.

31. A method as recited in claim 30, further comprising providing a processor, a memory, and a power supply within said protective cover, wherein said obtaining said data related to said strain from said mechanical force involves transmitting with said wireless communications device.

32. A method as recited in claim 28, wherein said protective cover further includes a second port for providing an exhaust while filling with said moisture barrier material.

33. A method of protecting a strain gauge on a structure surface, comprising:

a. providing a structure, wherein said structure has a structure surface;

b. providing a strain gauge, a moisture barrier material, and a preformed protective cover, wherein said preformed protective cover includes a vent to provide pressure equalization without allowing moisture to pass;

c. bonding said strain gauge to said structure surface with a bond, wherein said bond is susceptible to damage from moisture;

d. placing said preformed protective cover over said strain gauge and connecting said preformed protective cover to said structure surface to enclose said strain gauge within said preformed protective cover; and

e. providing said moisture barrier material within said preformed protective cover.

34. A method as recited in claim 33, wherein said preformed protective cover has an outer surface having a convex curvature, wherein said convex curvature extends from said structure surface.

35. A method as recited in claim 33, wherein said structure surface is subject to strain from a mechanical force other than that provided by bonding said strain gauge to said structure surface, wherein said bonding said strain gauge to said structure surface is for obtaining data related to said strain from said mechanical force, further comprising obtaining said data related to said strain from said mechanical force.

36. A method of protecting a strain gauge on a structure surface, comprising:

a. providing a structure, wherein said structure has a structure surface;

b. providing a strain gauge, a moisture barrier material, and a preformed protective cover;

c. bonding said strain gauge to said structure surface with a bond, wherein said bond is susceptible to damage from moisture, wherein said bonding said strain gauge includes providing said strain gauge on a backing, providing a light curable adhesive, positioning said strain gauge on said backing on said structure with said light curable adhesive, and exposing said light curable adhesive to light; and

d. placing said preformed protective cover over said strain gauge and connecting said preformed protective cover to said structure surface to enclose said strain gauge within said preformed protective cover; and

e. providing said moisture barrier material within said preformed protective cover.

37. A method as recited in claim 36, wherein said backing includes fiberglass.

38. A method as recited in claim 36, further comprising providing a bonding pad on said backing for providing electrical contact to said strain gauge, wherein said bonding pad includes at least one from the group consisting of a window and a stripe for facilitating light transmission to said light curable adhesive.

39. A method as recited in claim 36, wherein said preformed protective cover has an outer surface having a convex curvature, with wherein said convex curvature extends from said structure.

40. A method as recited in claim 36, wherein said backing transmits UV light, wherein said light curable adhesive is UV light curable, wherein said exposing said light curable adhesive to light involves exposing said UV light curable adhesive to UV light.

41. A method as recited in claim 36, wherein said structure surface is subject to strain from a mechanical force other than that provided by bonding said strain gauge to said structure surface, wherein said bonding said strain gauge to said structure surface is for obtaining data related to said strain from said mechanical force, further comprising obtaining said data related to said strain from said mechanical force.