CA1095377A - Porous elastic bandage - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A lightweight, porous knitted elastic bandage is produced from a warp of false-twist synthetic yarns with a filling inlay of regular yarns. The filling yarns are arranged in varying patterns across the warp yarns so that a portion of their length lies in looped and cursive configuration upon the surface of the bandage, and the structure is so open that overlapping layers of the bandage cling to each other in substantially non-displaceable relationship.

Description

This invention relates to a knittecl elastic bandage :Eor surgiGal or supportive purposes. Mo.re particularly~ it relates to a knitted bandage of a lightweight open, porous nature in which overlapping layers cling to each other to form a relatively non-slipping type of support.

BACKGROUND OF THE TNVENTION.

Historically, elastic bandages have been made in a woVen struc~
ture, using narrow or ribbon looms~ wherein the retractive and supportive power has been supplied by special warp yarns. Eaxly bandages employed overtwisted cotton warp yarns, as shown in ~ ' the U.S. paten~,to Teufel, 1~0.8~ No~ 889~827 or to Kle~n~ 1932 No. 1!875~740.

The use'of cotton warp ya,rns has beeD displaced tQ a con'side.rable extent by.the:use of elastome~ic Wa,rp ya,~ns~ initiall~ of ext~uded or'cut xubbe~, more xecently o~ ~thér ela,stomex~i.c m~n~
made pol~mers~ Such elastomexlc wa,~p ya~ns are usu~lly ~r.a~pea with a la~er of'non~ela,sto~eric fil,a.ments, Such banda~es~ ~lthough.effecti,ye in u~s,e~ suffer f~om the ~-` ' disadv~nta~e'~f being rel'atiyely expen~ye~ They a~e Px~d'uce.'d . ~.
singly Qn ~ na~row lQom~ utiliz~n~ expensi,ye ~xapped eIa'stomer'~c yarns~ ~t compa,rat~e,ly slo~ p~duction rate$, inherent i~n, t~e wea~in~ ~rocess, In an atte~pt to ciXcum~ent the l,i,~ita,tions of the wea~ing process~ it:ha;s been propo$ed to ~oduce! ela~tlc b~nda~es in.
knitted str.ucture~ as in.U~ S. P~,tent 3265.7Q3, to B~rnh~xdt~.

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The knit structu.res thus far proposed, however, skill employ elastomeric yarns as part of the warp structure, and customarily employ very heavy filling yarns to prevent necking-in of the bandage when stretched. They are relativel.y heavy in weight, averaging 6 to 12 o~. per square yard (204 to 408 grams per square meter), and due to their compact structure they become hot and uncomfortable to wear. ~lso, when applied to a limb or other body member they must be secured in place in the outer wrap by means of some sort of fastening, such as toothed metal clips. As the bandage is worn, the layers of the bandage tend to slip and slide past each other, leading to the undesirable alternatives oE
frequent removal and rewinding or else winding the bandage with ~ ~
an uncomfortable degree of tension. ~: :
`~ ~
It is with improvements in the production of bandages of this ..
type that the present invention is concerned.

SUMMARY OF THE INVENTION

It has now been found that by the utilization of so-called false ~ .
twisted filament yarns in the warp of long direction, ~ith a staggered inlay of regular yarns in the cross direction, a new type of elastic bandage can be produced which has stretch and power characteristics comparable with the characteristics of conventional elastic banda~es of woven structure. .:

The bandages of this invention comprise a set of composite parallel warp yarns in which a false~t~ist yarn is formed into stitch loop chains with a second false-twis~

353~7 yarn of opposite twist inlaid into the loops of the f irst false-twist yarn, and a plurality of individu~l Eilling yarns describing varied and cursive patterns inlaid across said compQsite warp yarns, the filling yarns overlapping one with another across a substan- , ;
tial portion of the width of said bandage, no individual filling yarn pattern extending across more than a minor portion of the width of said bandage, and a portion at least of the length of said filling yarns lying in slack looped configuration on the surface of said bandage.
:

~y false-twist yarns is meant ~ type of texturized continuous filament yarn which has been given increased bulk and loft, together with stretch, by the introduction into the yarn of crimps, loops, coils, and crinkles by false-twisting. Such yarns are commercially produced by well-known processes, and when the ~-filamentary material is thermoplasticr as is the case with nylon, a heat-setting stage in the false-twist process renders the stretch and the crimped configuration of the yarn relatively ~ ~
permanent. , Depending on the direction of rot~tion of the spindle, the yarn may be twisted clockwise or counterclockwiser giving rise to S-twist or Z-twist in the yarn. It is customary to employ yarns of both types of twist where it is desired to mini~ize tor~ue 9~3~7 , and twist in a fabric, either as alternate warp yarns or as a yarn of one twist plied with a yarn of opposite twist.

The warp yarns in the preferred bandage of this invention consist of false-twist S or Z yarns, knitted in a chain stitch with a false-twist Z or S yarn inlay. In order to minimize the tendency ~, of knitted fabrics to narrow in when stretched, the chain-stitched warps are held in position by a series of interlocking filling yarns Qf conventiQn~1 non-elastic type, preferably spun .' yarns, inla~d in a pa,rticular set of var~ing patterns which '~
will be descrihed more fully herein belo~.
. .
,. ~ : , , DESCRIPT.~ON OF THE INVENT:I~ON ::

The invention will be understood more fully with reference to ,:

the following description and drawings, in ,which~
;, .

~ FIGURE I is a magnified isometric view of a segment of a ~.. .i ~
preferred bandage of this inyention in relaxed state.

FIGURE 2 is a magnified view Qf a portion of such a bandage ~, under 50~ extension.

FIGURE 3 is: a highIy magn-i~ied vie~ of a fal~se-twist yarn used in the process of this invention.

.. ,.~ , . ~ :.:
r:` r :
F~GURE 4 is a formalized representation of the interrelationship ::

of th.e warp and filling yarns in the'bandages of this invention.
~.,.

~i..'' ~ 30 FIGURES 5, 6, 7 and 8 represent the paths of t~e ~nclividual "~. _ 4 _ -.,, ;~;
., ,., ,.,;.", .. ~ .
~, ,, ~ . ,:
,..

filling yarns in one repeat of a preferred embodiment oE khis invention.

FIGURE 9 is a composite of FIGURES 5, 6, 7 and 8~

FIGURES 10 and 11 represen-t the paths of the individual filling yarns in one repeat of a second embodiment o~ the invention.

FIGURE 12 is a composite of FIGURES 10 and 11.

For the sake of clarity, the involved nature of the false-twist warp yarns is shown only in FIGURE 3 Referring now to FIGURE 1, a preferred bandage of this invention comprises a set of warp yarns 10, interconnected ~y filling yarns 12 which are interlocked with at least a majority of the chain loops of the warp yarns. The bandage is of an open, porous con-struction, having an air porosity usually in excess of 500 cubic feed of air per square foot perminute at 0.5 inches of air -~
pressure, as tested on the Frazier air permeability device (18 cubic centimeters per square centimeter at 5 centimeters). This porosity is in part due to the lightweight of the bandages of this invention, which cusomarily lies in the range of 2 to 3 oz per square yard (68 to 102 grams per square meter), compared with conventional eIastic bandages which weigh 6 to 12 oæ. per square y~rd (204 to 40~ grams per square meter).

The lightweight and open weave na~ture of the preferred bandages `
of this in~ention have been found to minimize the tendency of the false-t~ist inlay yarns of a given type of twist~ S or Z, to impa~t curl to a bandage, pro~ided that the inlay ya:rns are com-1~ 339Sa~77 .

bined with a chain stitch yarn of opposite twist. For simplic-ity in manufacture, therefore, it is desirable to utilize warp yarns of composite nature, wherein each composite yarn consists either of a chain stitch S yarn with a Z twis-t inlay, or a Z
twist yarn with an S twist inlay~

The filling yarns 12 in FIGURE I are shown as lying slack, in cursive or looped configuration on the surface of the bandage.
This relaxed condition of the filling yarns is important in that 10 it allows the elasticity of the false-twist yarns 10 to ~e ~ ;
utilized without any substantial necking-in or widthwise con-traction when the bandage is stretched. It is due in part to a heat-shrinkage process to which the bandage is subjected after it comes from the warp-knitter or crochet machine. Probably in greater part, however, the relaxed condition of the filling yarns is due ~o the unusual manner in which the lightweight filling yarns - . .
are deployed through the warp yarns, as shown schematically in FIGURES 5, 6, 7 and 8 the arrangement of the individual filling yarns in a preferred embodiment of the invention, and in F~GURE 9 ~ `
: .
~ 20 a composite of all four filling yarns, each governed by an - ;
,:
individual guide bar. In the bandages of this invention the ;
filling yarns do not progress in uniform fashion acro s the warp yarns, as in prior art elastic bandages, but are arranged in off- ;;
setting pairs across the banda~e. The pairs may be ar~anged in ~ ~;

diagonal fashion~ as in FIGURES 5 and 6; in reciprocating fashion, as in FIGURES 7 and 8; in staggered fashion, as in FIGU~ES 1~ and 11; or in ~arious combinations of these. Each individual filling yarn extends over only a portion of the warp yarns: as illustrat-ed in F~GURES 5 and 6, the filling yarns 12A and 12B are inlaid in 9 warp y~rns, in a preferred em~Qdi~ent of the inyen~ion while the filliny yarns 12C and 12D oE FIGURES 7 and 8 are inlaid in 5 warp yarns. Since there are 1~ warp yarns per inch in this bandage, a bandage four inches wide will contain 7 pairs of fill-ing yarns 12A and 12~ and 11 pairs of yarns 12C and 12D.

Yarns 12C and 12D both terminate their lateral path on a common yarn: as shown in FIGURE 9, at 14, this is the fifth warp yarn in a nine-yarn r~peat.

PREFERRED EMBODIMENT OF THE INVENTION . ~;

Using a crocheting machine, a bandage was constructed utilizing five yarn guide bars per repeat operating in a vertical plane perpendicular to the horizontal needles, four of the bars moving across the width oE the fabric to insert the filling yarns of 30/1 cotton and the fifth bar being utilized to insert the inlaid false-twist yarn lOA or 10B. The filling yarn pattern was that shown in FIGURES 5, 6, 7, and 8, each of .he yuide bars ~i operating independently. The composite false-twist yarns 10 were 70~1/17 Z twist inlay and 70/1~17 S twist chain stitch 9uperloft nylon, a trade name for false-twist yarns made on a Leesona false-twist apparatus. There were nine warp yarns in each repeat, a total of 57 needles ~eing used in the production of a ~our-inc~ (10 centimeter) bandage ~it~ 14 composite warp yarns per inch (5.5 yarns per centimeter). The filling yarn of 30~1 cotton was inserted at the ra~e o~ 17 picks per inch (6.7 yarns per centimeter).

~s seen in FIGURE 4, the cottQn filling yarn is inlaid into each of the loop-forming S yarns ~n the composite warp yarns, 3~P7 FIGURES 5, 6, 7, and 8 illustrate the particular patte.rns with which each of the four filling yarns i5 deployed, to form the composite ~illing yarn structure shown in FIGURE 9.

The bandage as formed on the machine has a weight o~ about 60 ~rams per square yard or 72 grams per square meter. It is then conditioned by exposing it, untensioned, to moist stea~ at ahout 140F (60~C) for one to two hours, after which it is dried. Dur-ing this steaming process the bandage undergoes shrinkage, in-creasing in weight to about 70 grams per square yard or 84 gramsper square meter. In addition, the filling yarns are relaxed from their ofE-machine regular configuration to the cursive con-figuration shown in FIGURE 1. This relaxation builds slack into the filling yarns, and in part accounts for the ability of the bandage to be stretched without an accompanying decrease in width.

The finished bandage had an air porosity of over 90~ cubic feet of air per square foot per minute at 0.5 inches pressure, as tested on the Fraziex air permeability apparatus (32 cubic centimeters per square'centimeter per minute at 5 centimeters pressure).

At I00~ elongation the bandage had 9 picks or filling yarns per inch (3.5 per centimeter) with.14 composite warp yarns per inch.
Since the filling yarns were 30/1, the filling cover factor was about 2, ~n extr'emely low fact~x cha,racteristic of open-mesh netting. Co~er factor is a m,easure of the degree of openness of a fabric, and is calculated as the number of yarns per inch divided by the square root of the yarn count in the cotton system.
In the bandages of this invention, the number of filling yarns . ~ .
~ _ 1. , .

5~

per inch of bandage under 100~ extension preferably lies within the range of 8 to 20 (3 to 7.5 per centimeter~ with the filling yarns ranging from 20's to 60's in count, so that the cover factor is less than 5~

This low cover factor in the illing brings the crimpedl curled, and looped nature of the warp yarns into prominence as a dominant sur~ace characteristic of the bancLages of this invention.
When the bandage is applied to a body member in the custo.nlary overlapping layer procedure, each layer of the bandage clings firmly to each adjacent layer with which it is in contact, due to the interlocking of the crimps and curls of the warp yarns in one layer with the warps in adjacent layers and with the open, ~' widely-spaced filling yarn structure. Thus the bandage resists slipping and displacement as the body member is flexed during movement, an advantage not present in conventional elastic ~
bandages. :

~: OTHER EMBODIMENT OF THE INVENTION.

Using warp yarns of 70 denier 23 filament false~twist nylon~ ~ .
arranged in the same S and Z twist p~tterns as in the preferred example above~ a bandage was constructed utilizin~ three quide ~; bars. T~ bars inserted the 30~1 cotton filling yarns in.the patterns shown at 12E and 12F in FIGURES 10 and 1.1. The oyerlap of these yarns is shown at 14 in FIGU~E 12, a compos`ite'o~
FIGURES 10 and 11. ~ain there were nine warp yarns pe~ repeat.

Since only two filling yarns were employed, the third guide bar waS changed frsm ~hrowing one needle per link ta tWo nee.dles per link~' so that adjacent warp yarns were held toge-the'r not on'ly by g _ .

-the filling yarns but by the inlay false-twist yarn lOA or lOB
of FIGURE 4.

After relaxation by steaming, the bandage we.ig.hed 63 yrams per square yard ~76 grams per square meter), with 16 warp yarns and 21 filling yarns per inch (6 warp yarns and 8 filling yarns per centimete.r~. The porosity was in excess of 500 cubic feet of air per s~uare foot ~er minute at 0.5 inches pressure (18 cubic centimeters per square centimeter at S centimeters pressure).

Typical ~andages of th.is in~ention are characterized by an ability to be stretched in substantially the same ranye as conventional ;
elastic bandages, a repr~esentative range being 60% stretch under a force o~ lO pounds (4.5 kg.) up to 170% stretch under a force :~
of 50 pounds (22.5 kg.). In additiQn to being lightweight and comfortable to wear( due to their porosity, they are absorbent, and are easy to wash and sterilize. Since they contain no rubber or synthetic elastomeric ma~erial, they may be used in cases where elastomer yarns in contact with the skin give rise to an allergenic reaction.

It Will be appreciated by those skilled in the art that, unlike the production of woven bandages on a narrow loom, the knitted bandages of this invention may be produced on a wide flat-bed machine, and that a plurality of bandages, of varying widths if desired, may be produced in a single machine operation using a tie~in yarn between individual bandages if necessary, said yarn :

being readily removed su.bse~uently by an unraveling operation.
'~
The above description o~ th~ bandage is to be regarded a~

exemplary only, and other size~ ~ y~rn and knit-ting patterns ~,~

la~s3~7 ~ay be ut.ilized without departing rQm the spirit of the invention.

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Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A self-supporting, open mesh knitted elastic bandage characterized by the tendency of overlapping layers of the bandage to cling to each other in relatively non-displaceable relationship, which comprises a set of composite parallel warp yarns comprising a first false-twist yarn formed into stitch loop chains with a second false-twist yarn inlaid into the loops of said first false-twist yarn, said second false-twist yarn being of opposite twist from the twist of said first false-twist yarn, and a plurality of individual filling yarns describing varied and cursive patterns across said set of composite warp yarns and being inlaid therewith, said varied and cursive patterns of filling yarns overlapping one with another across a substantial portion of the. width of said bandage, no individual filling yarn pattern extending across more than a minor portion of the width of said bandage, and a portion at least of the length of said filling yarns lying in slack looped configuration on the surface said bandage?

2. The bandage according to claim 1 in which the filling yarn cover factor is less than 5 when the bandage is under 100%
extension.

3. A bandage according to claim 1 in which the warp yarns are of heat-set thermoplastic material.

4. A bandage according to claim 1 in which the warp yarns con-sist alternately of chain-stitch false-twist S yarns with a false-twist Z yarn inlay and chain-stitch false-twist Z yarns with a false-twist S yarn inlay.

5. The bandage according to claim 1 in which pairs of filling yarns are arranged in reciprocating diagonal fashion across a plurality of said warp yarns, and other pairs of filling yarns are arranged in alternating mirror-image fashion across a plurality of said warp yarns, said filling yarns overlapping with each other across a substantial portion of said warp yarns.

6. The bandage according to claim 1 in which a multiplicity of pairs of filling yarns are arranged in reciprocating staggered and overlapping fashion across a plurality of said warp yarns.