GB1603731A

GB1603731A - Braided textile artefacts

Info

Publication number: GB1603731A
Application number: GB5320/78A
Authority: GB
Original assignee: TBA Industrial Products Ltd
Current assignee: TBA Industrial Products Ltd
Priority date: 1978-05-30
Filing date: 1978-05-30
Publication date: 1981-11-25

Description

(54) IMPROVEMENTS IN AND RELATING TO BRAIDED TEXTILE ARTEFACTS (71) We, TBA INDUSTRIAL PRO DUCTS LIMITED, a Company organised under the laws of Great Britain, of 20 St.

Mary's Parsonage, Manchester M3 2NL (formerly of 77 Fountain Street, Manchester M2 2EA), do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to the manufacture of braided textile artefacts. The term artefacts in this context includes packing materials. According to the invention a braided textile artefact is made from knitted cord comprising glassfibre material. "Knitted" for present purposes includes closely allied techniques such as crocheting. The cord is preferably knitted from continuous filament yarn and may optionally include a core of the same or a different material.It may also be knitted from multi filament yarns which are plied or otherwise associated with continuous filaments of a different material, as will be discussed later. Where a core is used it may be of a nonbulky twisted or untwisted continuous filament material. It may also be of a twisted or untwisted staple fibre material. The core may be of glass fibre material. Multifilament glass yarn is a particularly preferred material from which to knit the cords and a particularly preferred knitting method is weft knitting on a very small diameter circular knitting machine.

Two, three or four needle machines are especially suitable for making cords which are to be used as yarns for further processing, whereas for a cord which is knitted around a relatively bulky core, a machine having more than four needles is appropriate.

It has been found that because of the relatively high bulk of the knitted structure and its ability to undergo laterial and/or longitudinal extension, braided textile articles made from knitted cords also exhibit a degree of bulk, elasticity, and flexibility which is not normally associated with such textile artefacts made from conventional yarns of the same material. This is particularly useful in the case of glass which is very difficult to bulk by normal texturising processes.

In the case of glass, texturising processes are generally unsatisfactory because at least some of the filaments tend to become damaged during the bulking operation. However, even glass yarns which are not amenable to texturising may be knitted into cords and thereafter made into braided textile artefacts which possess bulk, elasticity, and flexibility.

Bulk is of course a measure of the voids within a textile yarn and/or artefact and where the artefact is made from knitted cords in accordance with the invention, it is not necessary to start by bulking the individual continuous filament yams from which the cords are knitted. In the case of glass yarn therefore, at least some of the benefits of yarn bulking can be achieved without subjecting it to a potentially-damaging texturising operation before converting the bulked yarn into an artefact.

The knitted cords may be weft knitted around a central core for example, to " fill in " the hollow centre of the cord and thereby inhibit collapse of the knitted tube during subsequent conversion into an artefact. The core may also serve to limit the longitudinal extensibility of the cord. However, a knitted cord may also be used as a core around which a further cord is knitted. Such a core would give a more extensible product. The individual continuous filament yarns may be plied with a yarn of a different material prior to knitting or they may be simply associated with such a yarn, being fed simultaneously to the same needle of the machine without any prior twisting step.This has been found particularly useful for glass yarns, where the inclusion of a synthetic polymeric yarn such as nylon appears to stabilise the knitted cord to a significant degree by locking the loops together in some way. This locking effect reduces the tendency for the knitted cord to " run", i.e. to unravel from the last-knitted stitch towards the first-knitted end of the cord. This is par ticularly important for glass which is relatively inelastic and prone to unravelling when knitted alone.

It is preferred that the knitted cord is produced on only two, three or four needles as otherwise the tubular structure of the cord becomes pronounced and tends to flatten into a ribbon on braiding.

Textile artefacts made from knitted cords comprising glass fibre material have many uses, especially in industry. Their high bulk enables them to be used to absorb and/or retain liquids, viscous fluids, greases, solid lubricants and the like. It follows that they can be used in the production of packings. It is possible to produce braided packings from such cords which have greatly improved bulk, elasticity and flexibility when compared with similar braided packings made directly from the same glass yam. These improved packings are easier to impregnate with lubricants such as grease, graphite and p.t.f.e. and are more readily conformed to fit a stuffing box, or similar housing to be sealed.

The method of producing knitted cords for the purpose of the invention is essentially conventional and presents only the usual difficulties for a technician in that yarn tension, knitting speed, the number of needles and the cord take-up rate must all be selected in accordance with the textile artefact to be made and also in accordance with the yarn material, or materials, as the case may be. Single or multiple cams/feeders may be used.

Conversion of the knitted cords into artefacts, by braiding, presents no unusual difficulty, although due allowance must be made for relaxation caused by the elasticity of the cord.

In order that the invention be better understood, preferred embodiments of it will now be described by way of example.

Example 1.

Cords were weft-knitted from a nominal 132 tex glass yam at 10.5 courses/cm. on a circular knitting machine with a single feeder and cam, using four needles. The cord was of 2330 tex and diameter 1.7 mm. It was then braided at 24 plaits/dm. on an 8 spindle machine to form a round packing about 10 mm. in diameter. This packing was remark ably flexible and resilient in comparison to similar packings made conventionally from continuous filament or staple glass yams. It was used for dry sealing applications.

Example 2.

A 1900 tex cord was weft knitted at 10* courses/cm on a 3 needle circular machine using a single feeder and cam, from two ends of 66 tex multifllament glass yarn and one end of 10 tex nylon. The product was generally tighter than those of the previous examples, being somewhat firmer in its handle and less extensible, although it was still quite resilient.

It was braided on a 16 spindle maypole braidery machine at about 32 plaits/dm around 12 parallel ends of the same cord as a core. A firm, but resilient dry packing resulted having a diameter of about 9.5 mm. It was used for dry sealing purposes.

Example 3.

A 1700 tex cord was weft knitted as in Example 2, but at 8.5 courses/cm. It was very soft and extensible by comparison with the cord of Example 2 and on braiding at 23+ plaits/dm around 1, 3 and 7 ends of the same cord gave three soft, deformable packings of 8, 8.7 and 9.5 mm diameter, respectively.

These packings were much softer and more resilient than the packing of Example 2 and very different to conventionally-manufactured glass packings, which tend to be hard and unyielding. After treatment with a flexable, heat resisting black paint, these three packings were used as oven door seals.

WHAT WE CLAIM IS: 1. A braided textile artefact or packing material made from knitted cord comprising glass fibre material.

2. A textile artefact according to claim 1 wherein the cord is knitted from a continuous filament yarn.

3. A textile artefact according to claim 1 or claim 2 wherein the cord is knitted from a multifilament yarn.

4. A textile artefact according to any preceding claim wherein the cord is knitted around a core of the same or of a different material.

5. A textile artefact according to claim 4, wherein the core is of a non-bulky, twisted or untwisted continuous filament material 6. A textile artefact according to claim 4, wherein the core is of a twisted or untwisted staple fibre material.

7. A textile artefact according to claim 4, wherein the core is a knitted cord.

8. A textile artefact according to any preceding claim wherein the cord is knitted around a glass fibre core.

9. Textile artefact made from knitted glass fibre cord substantially as hereinbefore described with reference to and as illustrated by the Examples.

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Claims

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ticularly important for glass which is relatively inelastic and prone to unravelling when knitted alone.

It is preferred that the knitted cord is produced on only two, three or four needles as otherwise the tubular structure of the cord becomes pronounced and tends to flatten into a ribbon on braiding.

Textile artefacts made from knitted cords comprising glass fibre material have many uses, especially in industry. Their high bulk enables them to be used to absorb and/or retain liquids, viscous fluids, greases, solid lubricants and the like. It follows that they can be used in the production of packings. It is possible to produce braided packings from such cords which have greatly improved bulk, elasticity and flexibility when compared with similar braided packings made directly from the same glass yam. These improved packings are easier to impregnate with lubricants such as grease, graphite and p.t.f.e. and are more readily conformed to fit a stuffing box, or similar housing to be sealed.

The method of producing knitted cords for the purpose of the invention is essentially conventional and presents only the usual difficulties for a technician in that yarn tension, knitting speed, the number of needles and the cord take-up rate must all be selected in accordance with the textile artefact to be made and also in accordance with the yarn material, or materials, as the case may be. Single or multiple cams/feeders may be used.

Conversion of the knitted cords into artefacts, by braiding, presents no unusual difficulty, although due allowance must be made for relaxation caused by the elasticity of the cord.

In order that the invention be better understood, preferred embodiments of it will now be described by way of example.

Example 1.

Cords were weft-knitted from a nominal

132 tex glass yam at 10.5 courses/cm. on a circular knitting machine with a single feeder and cam, using four needles. The cord was of 2330 tex and diameter 1.7 mm. It was then braided at 24 plaits/dm. on an 8 spindle machine to form a round packing about 10 mm. in diameter. This packing was remark ably flexible and resilient in comparison to similar packings made conventionally from continuous filament or staple glass yams. It was used for dry sealing applications.

Example 2.

A 1900 tex cord was weft knitted at 10* courses/cm on a 3 needle circular machine using a single feeder and cam, from two ends of 66 tex multifllament glass yarn and one end of 10 tex nylon. The product was generally tighter than those of the previous examples, being somewhat firmer in its handle and less extensible, although it was still quite resilient.

It was braided on a 16 spindle maypole braidery machine at about 32 plaits/dm around 12 parallel ends of the same cord as a core. A firm, but resilient dry packing resulted having a diameter of about 9.5 mm. It was used for dry sealing purposes.

Example 3.

A 1700 tex cord was weft knitted as in Example 2, but at 8.5 courses/cm. It was very soft and extensible by comparison with the cord of Example 2 and on braiding at 23+ plaits/dm around 1, 3 and 7 ends of the same cord gave three soft, deformable packings of 8, 8.7 and 9.5 mm diameter, respectively.

These packings were much softer and more resilient than the packing of Example 2 and very different to conventionally-manufactured glass packings, which tend to be hard and unyielding. After treatment with a flexable, heat resisting black paint, these three packings were used as oven door seals.

WHAT WE CLAIM IS: 1. A braided textile artefact or packing material made from knitted cord comprising glass fibre material.
2. A textile artefact according to claim 1 wherein the cord is knitted from a continuous filament yarn.
3. A textile artefact according to claim 1 or claim 2 wherein the cord is knitted from a multifilament yarn.
4. A textile artefact according to any preceding claim wherein the cord is knitted around a core of the same or of a different material.
5. A textile artefact according to claim 4, wherein the core is of a non-bulky, twisted or untwisted continuous filament material
6. A textile artefact according to claim 4, wherein the core is of a twisted or untwisted staple fibre material.
7. A textile artefact according to claim 4, wherein the core is a knitted cord.
8. A textile artefact according to any preceding claim wherein the cord is knitted around a glass fibre core.
9. Textile artefact made from knitted glass fibre cord substantially as hereinbefore described with reference to and as illustrated by the Examples.