Pressure sensing fabric

• US 7,544,627 B2
• Filed: 05/12/2005
• Issued: 06/09/2009
• Est. Priority Date: 05/12/2005
• Status: Active Grant

• Current Assignee: Hong Kong Polytechnic University
• Original Assignee: Hong Kong Polytechnic University
• Inventors: Zhang, Hui, Tao, Xiao-ming
• Primary Examiner(s): JOHNSON, JENNA LEIGH
• Application Number:
  US11/127,142
• Publication Number:
  US 20060258247A1
• Time in Patent Office: 1,489 Days
• Field of Search: 442/301, 442/189, 442/308
• US Class Current: 442/189
• CPC Class Codes: D03D 1/0088 Fabrics having an electronic function
• CPC Class Codes: D03D 15/258 Noble metal
• CPC Class Codes: D03D 15/49 textured chenille D03D27/18; curled; crimped
• CPC Class Codes: D03D 9/00 Open-work fabrics
• CPC Class Codes: D04B 1/14 Other fabrics or articles characterised primarily by the use of particular thread materials
• CPC Class Codes: D04B 21/14 Fabrics characterised by the incorporation by knitting, in one or more thread, fleece, or fabric layers, of reinforcing, binding, or decorative threads; Fabrics incorporating small auxiliary elements, e.g. for decorative purposes pile fabrics D04B21/02; non-woven fabrics in general D04H
• CPC Class Codes: D10B 2101/08 Ceramic
• CPC Class Codes: D10B 2101/12 Carbon; Pitch
• CPC Class Codes: D10B 2101/20 Metallic fibres
• CPC Class Codes: D10B 2201/02 Cotton
• CPC Class Codes: D10B 2211/02 Wool
• CPC Class Codes: D10B 2211/04 Silk
• CPC Class Codes: D10B 2331/02 polyamides D10B2331/08 takes precedence
• CPC Class Codes: D10B 2331/021 aromatic polyamides, e.g. aramides
• CPC Class Codes: D10B 2331/04 polyesters, e.g. polyethylene terephthalate [PET]
• CPC Class Codes: D10B 2401/061 elastic
• CPC Class Codes: D10B 2401/16 antistatic; conductive
• CPC Class Codes: D10B 2403/02431 with electronic components, e.g. sensors or switches
• CPC Class Codes: D10B 2501/00 Wearing apparel
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: Y10T 442/3065 : Including strand which is of specific structural definition
• CPC Class Codes: Y10T 442/3179 : Woven fabric is characterized by a particular or differential weave other than fabric in which the strand denier or warp/weft pick count is specified
• CPC Class Codes: Y10T 442/3976 : Including strand which is stated to have specific attributes [e.g., heat or fire resistance, chemical or solvent resistance, high absorption for aqueous composition, water solubility, heat shrinkability, etc.]
• CPC Class Codes: Y10T 442/425 : Including strand which is of specific structural definition
• CPC Class Codes: Y10T 442/45 : Knit fabric is characterized by a particular or differential knit pattern other than open knit fabric or a fabric in which the strand denier is specified

Abstract

Existing pressure sensing fabrics may involve two portions, i.e., insulating and conductive portions in the fabric, which increases the complexity of the fabric system and more important, and the instablization of the resistance-strain relationship during dynamic deformation which limits the application fields due to intrinsic properties difference between the two portions. These fabrics commonly employ two or more layers to accomplish the detecting functions. Such arrangements increase the thickness, weight, and cost of the sensors with some other disadvantages such as low accuracy, instability, etc. This invention describes a pressure sensing fabric have a general structure as simple as a plurality of electrically conducting yarns forming interlocking loops of yarns. The pressure sensing fabric is found not only be able to sense pressure but also the magnitude of the pressure.

Claims

1. A pressure or strain sensing fabric, the fabric comprising at least one elongate electrically conductive yarn, wherein one or more of said electrically conductive yarns is arranged as a series of loops of the same yarn, at least one of the loops of said series of loops of said one or more yarns being interlocked with another loop of said series of loops;

wherein the loops are interlocked in a manner such that the contact area between adjacent loops can be altered so as to alter the electrical resistance along the length of the yarn.

2. The fabric of claim 1, wherein the yarn comprises staple fiber yarn.

3. The fabric of claim 1, wherein the yarn comprises filament yarn.

4. The fabric of claim 1, comprising a plurality of electrically conductive yarns, wherein each of the electrically conductive yarns forms interlocking rings.

5. The fabric of claim 1, wherein the fabric includes one or more strands formed from two or more yarns, a portion of the loops of one yarn being interlocked with loops of at least one adjacent yarn forming said strand.

13. The fabric of claim 1, wherein the loops are interlocked in a manner such that, upon a tensile load being applied to the yarn, a loop is urged away from an adjacent loop and such that a portion of the loop is urged against a portion of an adjacent loop so as to increase the contact area between the loop and the adjacent loop.

6. A pressure and position sensing fabric including a first plurality of electrically conductive fabrics comprising a plurality of electrically conductive yarns, said electrically conductive yarns arranged so as to intersect at predetermined known positions, wherein one or more of said electrically conductive yarns is arranged as a series of loops of the same yarn, at least one of the loops of said series of loops of said one or more yarns being interlocked with another loop of said series of loops;

wherein the loops are interlocked in a manner such that the contact area between adjacent loops can be altered so as to alter the electrical resistance along the length of the yarn.

7. The fabric of claim 6, wherein the yarns are provided so as to intersect in an orthogonal array arrangement.

8. The fabric of claim 6, wherein the yarns are provided so as to intersect in a non-orthogonal array arrangement.

9. The fabric of claim 6, wherein yarns are provided so as to intersect in a spherical array arrangement.

10. The fabric of claim 6 further including a first plurality of insulating fabrics including insulative yarns, wherein the electrically conductive fabrics are spaced apart from each other and the insulative fabrics are interwoven therebetween.

11. The fabric of claim 6, wherein the yarns are staple fiber yarns.

12. The fabric of claim 6, wherein the yarns are filament yarns.