Knitted fabric
A knitted fabric is disclosed, comprising a first fabric layer, a second fabric layer and a plurality of pliable threads having a predetermined length, the respective ends of the pliable threads being stitched to the first and second layers thereby connecting the first and second layers. Preferably the fabric also contains sacrificial yarn to tie in the pliable threads. Also disclosed is a method for knitting a fabric according to the invention. The fabric has uses in inflatable devices, including airbags, or lifting devices.
1. A knitted fabric comprising,
a first layer,
a second layer,
a plurality of pliable threads formed of a multi-filament yarn, each pliable thread having at least one portion of a predetermined length, opposing ends of each portion of the plurality of pliable threads being stitched respectively to the first and second layers thereby connecting the first and second layers, and
a sacrificial yarn inlaying at least some of the plurality of pliable thread portions between their opposing ends with one or both of said first and second layers such that the first and second layers are separable a distance corresponding to a distance between a first inlay of a pliable thread portion and either an end of said pliable thread portion or a second inlay,
wherein with the inlay by the sacrificial yarn removed, the first and second layers are separable from one another the predetermined lengths of said plurality of pliable thread portions.
2. The knitted fabric as claimed in claim 1 , wherein the sacrificial yarn comprises a destructible yarn selected from the group consisting of a soluble yarn, an easily breakable yarn, and a yarn with a low melting temperature.
3. The knitted fabric as claimed in claim 1 , wherein the sacrificial yarn comprises polyvinyl alcohol.
4. The knitted fabric as claimed in claim 1 , wherein the fabric comprises one or more yarns selected from the group consisting of polyester, polyamide, polypropylene, flax, hemp, cotton, silk, wool and aramid.
5. The knitted fabric as claimed in claim 1 , wherein the predetermined length is 10 mm or greater.
6. The knitted fabric as claimed in claim 1 , wherein the knitted fabric has a density of 100 to 2000 g/m 2 .
7. The knitted fabric as claimed in claim 1 , wherein the fabric comprises one or more yarns having a linear mass density of 80 to 500 decitex.
8. The knitted fabric as claimed in claim 1 , further comprising a film on at least one of the first and second layers.
9. The knitted fabric as claimed in claim 8 , wherein the film is a laminated or a coated film.
10. The knitted fabric as claimed in claim 8 , wherein the film is a low permeability film.
11. The knitted fabric as claimed in claim 8 , further comprising an adhesive film to improve the adhesion of film to one or both of the first and second layers.
12. The knitted fabric as claimed in claim 8 , wherein the film comprises polyurethane, polyvinyl acetate, polyethylene terephthalate, an acrylic polymer or a polyester.
13. The knitted fabric as claimed in claim 1 , wherein the knitted fabric is a warp knitted fabric.
14. A method for the manufacture of a knitted fabric, the method comprising,
a) forming a first layer,
b) forming a second layer,
c) connecting the first layer and the second layer with a plurality of pliable threads formed of a multi-filament yarn, each pliable thread having at least one portion of a predetermined length, opposing ends of each portion of the plurality of pliable threads being stitched respectively to the first and second layers thereby connecting the first and second layers, and
d) using a sacrificial yarn to inlay at least some of the plurality of pliable thread portions between their opposing ends with one or both of said first and second layers such that the first and second layers are separable a distance corresponding to a distance between a first inlay of a pliable thread portion and either an end of said pliable thread portion or a second inlay, said distance being less than the predetermined length of the pliable thread portion.
15. An inflatable device comprising a knitted fabric of claim 1 .
16. An inflatable device as claimed in claim 15 , wherein the device acts as a personal air bag.
17. A garment comprising an inflatable device as claimed in claim 15 .
18. A lifting device comprising an inflatable device as claimed in claim 15 .
19. A knitted greige fabric comprising a knitted fabric as claimed in claim 1 .
20. The knitted fabric as claimed in claim 1 , wherein the predetermined length is 16 mm or greater.
21. The knitted fabric as claimed in claim 1 , wherein the predetermined length is 24 mm or greater.
22. The knitted fabric as claimed in claim 1 , wherein the predetermined length is 66 mm or greater.
23. The method as claimed in claim 14 , further comprising,
subsequently removing the inlay by the sacrificial yarn whereby the first and second layers are separable from one another by the predetermined lengths of said plurality of pliable thread portions.