Fabric-based strain gauge

• US 7,750,790 B2
• Filed: 01/19/2007
• Issued: 07/06/2010
• Est. Priority Date: 01/23/2006
• Status: Active Grant

• Current Assignee: Chang-Ming Yang
• Original Assignee: Chang-Ming Yang
• Inventors: Yang, Chang Ming, Chou, Chun-Mei
• Primary Examiner(s): LEE, KYUNG S
• Application Number:
  US11/655,199
• Publication Number:
  US 20070171024A1
• Time in Patent Office: 1,264 Days
• Field of Search: 338/2, 338/99, 338/101, 338/114, 338/210, 338/212, 338/259, 442/229, 442/256, 442/2, 428/357, 428/364, 428/408, 737/60, 737/68
• US Class Current: 338/2
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion
• CPC Class Codes: A61B 5/6805 Vests
• CPC Class Codes: G01L 1/22 using resistance strain gauges
• CPC Class Codes: Y10T 428/29 Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 442/102 Woven scrim

Abstract

The invention provides a strain gauge which includes a fabric base and at least one conductive yarn. In addition, the fabric base is weaved with a plurality of non-conductive yarns, and the fabric base thereon defines a sensing direction. Moreover, each of the conductive yarn is gimped by a textile process with one of the non-conductive yarns and is woven through the fabric base along the sensing direction. Furthermore, the at least one conductive yarn is capable of being applied by an electric power; when an external force acts on the fabric base, the geometrical property of the at least one conductive yarn alters so that a change of an electric property associated with the applied electric power is sensed to indicate an elongation of said strain gauge applied by the external force along the sensing direction.

Claims

1. A strain gauge, comprising:

a fabric base weaved with a plurality of non-conductive yarns, and the fabric base thereon defining a sensing direction; and

at least one conductive yarn, each of the conductive yarn being gimped with one of the non-conductive yarns by a textile process and woven through the fabric base along the sensing direction;

wherein the at least one conductive yarn is capable of being applied by an electric power;

when an external force acts on the fabric base, the geometrical property of the at least one conductive yarn alters so that a change of an electric property associated with the applied electric power is sensed to indicate an elongation or contraction of said strain gauge applied by the external force along the sensing direction.

2. The strain gauge of claim 1, wherein the electric property of the electric power is an impedance.

3. The strain gauge of claim 1, wherein the electric property of the electric power is a magnetic flux or an electric flux.

4. The strain gauge of claim 1, wherein at least one of the non-conductive yarns is elastic.

5. The strain gauge of claim 1, wherein the textile process is a weaving process or a knitting process.

6. The strain gauge of claim 1, wherein each of the at least one conductive yarn substantially contains textile fibers and metal fibers in an amount between 1 to 100 volume percentage.

7. The strain gauge of claim 6, wherein the metal fibers are formed of a stainless steel, a Ni—

Cr alloy, or a Cu—

Cr alloy.

8. The strain gauge of claim 7, wherein the diameter of each of the metal fibers is in a range from 1 μ

m to 30 μ

m.

9. The strain gauge of claim 1, wherein each of the at least one conductive yarn substantially contains textile fibers and metallic fibers in an amount between 1 to 100 volume percentage.

10. The strain gauge of claim 9, wherein the metallic fibers are formed from natural fibers, synthetic fibers, carbon fibers, or glass fibers, coated with Cu, Al, or Ag.

11. The strain gauge of claim 1, wherein each of the at least one conductive yarn is formed from an ultra-fine metal wire twisted with a plurality of textile fibers.

12. The strain gauge of claim 11, wherein the diameter of each of the ultra-fine metal wire is in a range from 10 μ

m to 80 μ

m.

13. The strain gauge of claim 12, wherein each of the ultra-fine metal wire is made of a stainless steel, a Ni—

Cr alloy, or a Cu—

Cr alloy.

14. The strain gauge of claim 12, wherein the strain gauge is capable of electrically connected to a monitoring circuit for detecting change of voltage of the strain gauge;

wherein when the strain gauge is elongated or contracted and maintained at a length for a period, the potential of the strain gauge detected by the monitoring circuit will be assigned as a reference potential.