GB2180563A

GB2180563A - Compression bandage

Info

Publication number: GB2180563A
Application number: GB08622476A
Authority: GB
Inventors: David Wilson
Original assignee: Clutsom Penn International Ltd; CLUTSOM PENN INTERNATIONAL Ltd
Current assignee: CLUTSOM PENN INTERNATIONAL Ltd
Priority date: 1985-09-16
Filing date: 1986-09-18
Publication date: 1987-04-01
Also published as: GB8622476D0

Abstract

A compression bandage intended to maintain the pressure originally applied, within preferred limits, is made from warp-knitted fabric (10, 11) incorporating a laid-in bare elastomeric yarn (12) which is at low or zero tension when the fabric is relaxed. The extensibility of the fabric is at least 175% and preferably 200%. The elastomeric yarn may be of natural or synthetic material and is laid into pillars (10), e.g. of crimped nylon yarn. The yarn (11) may be a flat, stretch or elastic yarn. <IMAGE>

Description

SPECIFICATION Compression bandage This invention relates to a compression bandage, that is an extensible bandage which is used to apply pressure to the part of the body covered by the bandage.

It is desirable that such a bandage should maintain the pressure initially applied (and not allow it to increase or decrease substantially) despite subsequent movements of the part of the body (e.g. limb) on which the bandage is used It is also desirable that the tension in the bandage during application should be readily controllable under normal conditions of use, so that a subbandage pressure within a preferred range can be achieved. Further, it is desirable that tension decay in the bandage (fall in tension during use, even without body movement) should be low.

A bandage according to the invention enables these requirements to be achieved satisfactorily.

A woven compression bandage incorporating bare rubber yarn is already known and a warpknitted bandage incorporating covered rubber yarn knitted into the fabric structure (as opposed to being laid in) is already known but a bandage of the present invention provides improved pressure characteristics over these known bandages.

According to the invention, a compression bandage comprises a warp-knitted fabric incorporating a laid-in bare elastomeric yarn which, when the fabric is in a relaxed state, is under low or zero tension, the fabric having an extensibility of at least 175%.

The invention also includes a method of manufacturing a compression bandage as just described.

The meaning of the term "extensibility" as used in this specification can be explained as follows. When the extension of a fabric is plotted against the force applied to the fabric, the resulting extensibility cure reaches a point where the extension increases only slightly with increasing force, that is, the curve approaches a line parallel to the force axis. It is sometimes said that the fabric "runs out of stretch". The increase in the length of the fabric over its initial length at this point divided by its initial length under zero applied force is the "extensibility". In practice, the extensibility of a fabric of the kind used in a compression bandage can generally be determined by stretching the fabric by hand since the forces involved are such that they can be applied in that way.The maximum extension for determining extensibility can thus be roughly determined by hand-stretching the fabric.

Preferably, the extensibility of the present bandage is 200% or more.

The term "rubber yarn" is used in this specification to mean yarn made from natural rubber (elastodiene), that is rubber based on naturally occurring polymers, as opposed to polymers achieved by synthesis.

Advantageously, the elastomeric laid-in yarn in a compression bandage according to the invention is a rubber yarn.

To warp-knitted structure of the present bandage may be such that each elastomeric yarn is incorporated in a pillar made of a non-elastic yarn knitted round the elastomeric yarn. This protects the elastomeric yarn and controls the extension properties of the fabric.

The invention will be further described, by way of example, with reference to the accompanying drawing which shows the lapping diagram of one warp-knitted fabric for a bandage according to the invention.

The fabric illustrated in the drawing is knitted on a 48 gauge (24 needles/inch (2.54cm) 4-bar raschel warp knitting machine, but only 3 of the bars are threaded, as follows: Table I Bar 1-a 2/78 decitex false twist crimped nylon yarn, 10.

Bar 2-empty Bar 3-a 110 dtx. flat nylon yarn, 11.

Bar 4-a 65's (Rubber Count) bare rubber yarn, 12.

All three bars which are used may be fully set (that is fully threaded) but fabric for use in the bandage of the invention may be produced with bar 4 half set, such a fabric having rubber yarn in alternate wales only. Bar 3 may also be half set giving a more open appearance to the fabric.

Preferred lapping movements are as follows.

Table II Bar 1-1-0/0-1 Bar 3-0-0/3-3 Bar 4-1-1/0-0 As an alternative, bar 3 may move 0-0/2-2 or 0-0/4-4 producing weft floats of different length.

As a further alternative, the rubber yarn may be threaded in bar 3 and the flat nylon yarn in bar 4, bar 3 will then be moved in a manner just described for bar 4 and bar 4 will be moved in a manner just described for bar 3.

Instead of using a bare rubber yarn on bar 4 (or bar 3) a synthetic elastomeric yarn may be used.

The basic structural features of the fabric described are that it comprises a ground fabric made of non-elastic yarn 10 comprising knitted pillars interconnected by weft floats of flat nylon yarn 11. Incorporated in the pillars are bare rubber (or synthetic elastomeric) yarns 12 which are thus covered or partly covered by the non-elastic yarn of the pillars.

In this example the ground fabric is made of nylon (polyamide) yarn and the yarn forming the knitted pillars is a stretch yarn, in this case crimped nylon. By a "stretch yarn" is meant a yarn of non-elastic material so treated during manufacture that it can be easily stretched from its relaxed length by deforming the structure rather than the material of the yarn. False twist crimped yarns are examples of such stretch yarns.

In manufacturing fabric for a bandage according to the invention, the elastomeric yarn and the other yarns are supplied to the needles in such a way as to produce a fabric structure which, when released from knitting tension allows the elastomeric yarn to relax to a condition of zero or very low tension.

In the present example, the fabric has 60 courses per inch (2.54cm) in the relaxed state and when extended to 200% of its original length has 20 courses per inch (2.54cm).

The inlay yarn supplied to bar 3 in the present example need not be a flat yarn. It may be a stretch yarn or an elastic yarn (rubber or a synthetic elastomeric yarn).

The extensibility of the fabric according to the present example is in excess of 200%. Fabric for the bandage according to the invention should have an extensibility of at least 175%.

It is believed that by using a crimped nylon yarn in the pillars of the present fabric structure a superior appearance is imparted to the fabric in the stretched and unstretched states.

By using bare rubber yarn in the present fabric, the cost of the fabric is reduced and the superior extension properties of rubber are achieved so that, by incorporating the rubber yarn in the fabric under low or zero tension, sub-bandage pressure can be better controlled and will remain more nearly constant in use. This is because a comparatively low slope of the loadelongation curve of the resulting bandage is thus achieved (compared with some currently marketed bandages) and the tension decay (fall in bandage tension during use) is comparatively low.

An important feature of the fabrics for bandages according to the invention described above is that the stitch structure and yarn tensions in the fabrics are such that at the extension in use, typically 50%, the yarns other than the said laid-in bare elastomeric yarns (of bar 4 in Tables I and II), remain in a relaxed state (that is at zero or very low tension) and play no part in supporting the stretching forces applied to the bandage. It is advantageous that at the tensions normally applied in use, the laid-in bare elastomeric yarns of bar 4 in Tables I and II should be the only yarns under significant tension in the bandage, because this produces a more nearly constant sub-bandage pressure. As a guide, this condition should preferably apply at 50% extension and this should be the recommended extension when the bandage is applied.

Claims

1. A compression bandage comprising a warp-knitted fabric incorporating a laid-in bare elastomeric yarn which, when the fabric is in a relaxed state, is under low or zero tension, the fabric having an extensibility of at least 175%.

2. A compression bandage according to claim 1, wherein the said fabric has an extensibility of at least 200%.

3. A compression bandage according to claim 1 or 2, wherein the elastomeric yarn is a rubber yarn.

4. A compression bandage according to any one of claims 1 to 3, wherein the said fabric has a structure such that each elastomeric yarn is incorporated in a pillar made of a non-elastic yarn knitted round the elastomeric yarn.

5. A compression bandage according to any one of claims 1 to 4, wherein the fabric has one third as many courses per cm when extended to 200% of its original length as exist when the fabric is in its relaxed state.

6. A compression bandage according to claim 1, substantially as herein described with reference to the accompanying drawing.

7. A compression bandage according to claim 1 or claim 6 and substantially as hereinbefore described with reference to Table I and Table II.