US1924598A - Elastic fabric - Google Patents

Description

Aug. 29, 1933. g 1,924,598

ELASTIC FABRIC Filed July 8, 1931 3 Sheets-Sheet l INVENTQR 75;: ATTORNEY.

Patented Aug. 29, 1933 V UNITED STATES ELASTIC FABRIC 7 Warner Eustis, Newton, Mass, assignor to The Kendall Company, Walpole, Mass., a corporation of Massachusetts Application July 8, 1931. Serial No. 549,344

16 Claims. (Cl. 154-48) This invention relates to elastic fabrics and to methods of making such fabrics.

The usual method of making elastic fabrics consists in interweaving thread or yarn with strands of rubber. to enclose saidstrands, the rubber being held under tension during the weaving operation. A well recognized objection to fabrics of this character is the fact that'when they are cut the rubber strands tend to pull back away from the cut edges due to the fact that they are normally maintained under an initial tension. When these rubber strands are subjected to increased tension during the use of the fabric, as for example when the fabric forms a part of a supporter, garter, or the like, the added tension increases the tendency to pull the ends of the rubber strands back into the fabric. It is a frequent occurrence even for these strands to be pulled through stitched seams and for the needles used in the stitching operation to cut one or more of the strands so that they are allowed to pull back. Occurrences of this kind not only reduce the elasticity of the fabric but theyv produce an unsightly article. This characteristic of elastic fabrics has long been recognized and it is usually regarded simply as a necessary disadvantage of such fabrics.

In addition, the nature of elastic fabrics is such that they must be woven in the widths in which they are to be used with a selvage at each edge in order to keep the fabric from ravelling. In other words, the ordinary elastic fabric cannot be cut into strips or died out into shaped pieces.

The present invention deals especially with these considerations. It has for its general object to improve both the construction and methods of manufacture of elastic fabrics with a view to eliminating the objcctionablefeatures above described. It is also an object of the invention to reduce the expense of manufacture of elastic fabrics.

The nature .of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

In the drawings,

Figure 1 is a perspective view illustrating steps in the manufacture of a fabric according to this invention;

Fig. 2 is a perspective view, partly in section and on a large scale, of a fabric embodying features of this invention;

Fig. 3 is a plan view of a section of fabric such as that shown in Fig. 2 illustrating the action which occurs in stretching the fabric;

Fig. 4 is a plan view on a large scale of a small portion of the fabric shown in Fig. 3;

Fig. 5 is a perspective view of a part of a roll which may be used in the apparatus shown in Fig. 1; and

Figs. 6, 7 and 8 are plan views illustrating different fabrics embodying features of this invention.

Stated broadly, the present invention proposes to make an elastic fabric by arranging a multiplicity of parallel disconnected threads side by side and closely adjacent to each other in the form of a layer, and applying a coating of rubber 7m to one surface of said layer and thereby securing said threads elastically together. The rubber coating may be continuous or discontinuous, as desired. If desired, also, a similar layer of threads may be united to the opposite side of said coating with the threads in one layer extending, parallel to those in the other layer.

"The nature of the thread or similar material used in the manufacture of such a fabric necessarily will vary widely in accordance with the g0 characteristics desired in the finished fabric. It may consist of agreat variety of stranded'materials such as thread, yarn, cord, and the like, and the term "thread as hereinafter used is intended to include all thesematerials. The fibre of which the thread is made also necessarily will be selected in accordance with the texture and surface characteristics desired in the final product.

According to the method of manufacture illustrated in Fig. 1 a multiplicity of threads 2 are unwound from a beam, or from any other source of supply, and are guided through a comb 3 and over a roll 4 to the surface of a relatively large roll or drum 5. In some cases it may be preferable to form circumferential grooves in the peripheryof the drum 5 in order better to hold the threads in the desired relationship. This is not necessary, however, when threads of fine gages are used. The drum 5 is revolved slowly in the direction indicated by the arrow, and as the threads move along with the surface of the drum a coating of rubber is applied to them. While rubber could be combined with these threads in 'a sheet form, better results are obtained by applying the rubber in a liquid form, a vulcanized latex preferably being used. This result may conveniently be accomplished by using a spreading or coating mechanism of a common form. The particular mechanism shown comprises a 0 trough 6 containing the supply of liquid rubber,

- a lifting or transfer roll '7 running in said trough,

and an applying roll 8 which takes the rubber from the roll 7 and applies it to the outer surface of the layer of threads on the drum 5. The arrangement preferably is such that the outer surfaces only of the threads are coated with rubber, and the inner surfaces are left uncoated, no substantial penetration of the rubber into the fibre of the thread being produced. This is conveniently accomplished by properly regulating the character of the coating liquid in a manner well understood by those skilled in this art. Preferably the drum 5 is heated so that the solvent or dispersing medium in which the rubber molecules are suspended is driven off while the threads are still in contact with the drum. If a two ply fabric is to be made, then a second layer of threads 10 may be unwound from a suitable supply beam, led through a comb 12 and over a roll 13 into contact with the coating of rubber'which has just been applied to the first layer ofthreads, the rubber coating serving to unite the threads of this second layer to each other in substantially the same way that it se-' cures the threads of the first layer to each other. After passing nearly around the drum 5 the fabric is led over a roll 14 and away from the drum and 1 is wound up at any suitable point.

This method produces an elastic fabric composed of multiple layers of parallel threads, the layers being held in superposed relationship by the intervening sheet of rubber applied during j the coating operation. This sheet of rubber is connected from each other except throu h their union with the coating of rubber, they are entirely free to move toward and from each other as the fabric is stretched more or less in a direction at right angles to the threads.

It is obvious that as many layers of thread may be used as desired. In light weight fabrics where the presence of an exposed surface of rubber is not objectionable, a single layer of threads only may be used. If the exposed surface of rubber is objectionable for any reason, then a two ply fabric, such as that illustrated in Fig. 1, probably would be preferred.

Both fabrics are elastic in all directions except that substantially parallel to the threads. Such fabrics may be cut into strips or blanked out into shaped pieces suitable for a great variety of uses and they completely avoid the objectionable characteristics above described of ordinary elastic fabrics.

Unique results which are of peculiar utility for a considerable variety 'of purposes may be produced by using threads in which the strands are twisted together very loosely, or, in other words, in which a very low twist is used. For example, thread often is made by plying together several ends" or strands of yarn having a standard twist. A twist of anywhere from ten to twenty turns per inch commonly is used in this plying operation. Frequently, also, in making thread of the coarser gages a plied thread such as that again a fairly high twist customarily is used,

say for example, in the neighborhood of ten turns per inch, although a twist considerably higher than this often is used. For the purposes of this invention I prefer to use a thread in which the strands are twisted together very loosely or with a very low twist, say for example, two to three so turns per inch. When threads of this character are associated in the manner illustrated in Fig. 1 a fabric such as that shown in Fig. 2 is produced. The individual threads in the upper layer of this fabric are indicated at 2' and correspending threads in the lower layer are shown at 10'. The intervening ply of rubber is shown at 9.

In this fabric, as in that above described, the threads in each layer are arranged in parallel relationship side by side and closely adjacent to each other and they are held in this relationship by the rubber sheet 9. Due to the fact, however, that the threads are loosely twisted they tend to flatten out where they pass over the roll 4-so that the individual strands in a transverse section of the fabric appear approximately as shown in Fig. 2. All of the strands are bonded to the rubber sheet at the surface of the layer adjacent to the sheet. The strands, however, are entirely free from the-rubber coating at the opposite surface of the layer. Considering any individual strand of a thread 2', as, for example, the strand a, it will be clear from an inspection of Fig. 2 that this strand ,is entirely free of the rubber sheet 9 for a considerable part of its length and until it passes under the other strands at about the point a, Fig. 2. It then is united to the rubber coating for a distance and is again freed from the coating when it passes up and over the other strands associated with it. This is also true of every other strand in the same thread. In addition. the rubber in the sheet is not of uniform thickness but it protrudes somewhat between adjacent threads of the same layer and is therefore somewhat thickefat these points than directly under the individual\ threads. Consequently, when such a fabric is" stretched in a direction at right angles to the threads, thefirst effect is to open the twist of the v t threads and to cause the strands of the threads to separate from each other at the side thereof opposite to the coating or sheet of rubber. This opening action becomes very marked before any substantial separation of adjacent threads from each other occurs.

Applicant has endeavored to illustrate this effect in Fig. 3 where the upper part of the fabric is being shown as stretched. Considering, for example, the strands a, b, c and d which are all twisted together toform one of the threads 2, the manner in which the twist of this thread is opened and the individual strands are separated from each other is clearly shown. This effect also is illustrated on a somewhat larger scale in Fig. 4. This action occurs because of the fact that the twist in the individual threads is so loose that less force is required to open the twist than is necessary to stretch the rubber between the threads in order to separate them.

Obviously a fabric of this character also can be made in single or multi plies, as desired. It can be made to give soft, pleasing surface textures which are especially desirable in fabrics that are to be worn next to the skin.

As indicated, fabrics made in any of the ways above described can be cut into strips of suitable dimensions or died out into shaped pieces. Whether the threads in these strips will extend longitudinally or transversely of the strips depends upon the direction in which it is desired to have the fabric stretch. One such strip is indicated at 16 in Fig. 6 with the threads 2 or 2' running transversely to the goods, which therefore are adapted to stretch longitudinally ofthe strip. In some cases it is desirable to limit'the degree to which such a fabric strip can be stretched and this may conveniently be done by running zig zag lines of stitching 17 along the opposite margins of the strip 16. The,-zig zag stitches will not interfere with the initial, or, in fact, a very considerable degree of stretching of the webb, but will limit the stretch after it has proceeded'to a certain point. This effect can also be produced by stretching the fabric and holding it stretched while stitching it in the direction of stretch with either a chain or lock switch, as desired. Such stitching will not interfere with the stretching of the fabric up to the limit determined by the threads of the stitches but will definitely prevent any substantial further stretch. This method has the advantage of predetermining the degree of the stretch to which the fabric can be subjected and fixing the limit of stretch at any point within the range of elasticity of the goods.

This effect canalso be produced less positively, but nevertheless with ample effectiveness, for many purposes, by running strip coatings 18, Fig. 7, of rubber along the opposite margins of .the uncoated sides of the fabric, these marginal strips serving to provide heavier and stronger bands of rubber at the margins and also to unite the ends of the threads'at the opposite edges -of the fabric to the underlying or main coat- As above stated, it is not essential for some purposes that'the coating of rubber be continuous. In fact, it is very desirable where a porous fabric is required that this rubber coating be discontinuous or of a foraminous character.

Coatings of this nature are shown in Figs. '1 and 8 at 9' and 9", respectively. These coatings may be regarded as strip coatings in which'the strips run transversely to each other. In the form shown in Fig. '7 relatively heavy rubber strips run transversely to the direction of the threads 2 and are connected by thinner and lighter longitudinal strips. In the fabric shown in Fig. 8 both sets of strips are of approximately the same weight and they both make an angle of approximately 45 with the direction of the threads 2. In applying the coating 9' shown in Fig. 7, a roll of the construction illustrated at 4 in Fig. 5 may conveniently be substituted for the roll 4 of Fig. 1, this roll having raised bar-shaped portions e to apply the strips e and narrower transverse connecting bars I to apply the strips f.

If it is desired to have the rubber coatings in these fabrics under an initial tension when the fabric is in its normal and unstretched or,

contracted condition, this result can be obtained by making the fabric in the manner above described, subsequently stretching the fabric slightly and, while maintaining the fabric in this stretched condition, loading the threads with a filler of some kind which will prevent the fabric from again returning to its original condition. For this purpose a great variety of fillers can be used, such as those commonly employed in loading fabrics. This results in preventing the rubber coating from returning completely to its original condition when it is released, since the threads or the strands of which they are composed are held separated to some extent when the fabric is contracted by the filling or loading material which has been applied to them. Consequently, the rubber coating is held under some rubber sheet stretched somewhatduring the operation of uniting it tothe layer of threads.

It will "be clear from the foregoing descrip tion that the invention provides an elastic fabric having essentially the same properties and advantages of those made by prior methods. but which, in addition, avoids certain of the objec-' tions above described which are inherent in the latter fabrics. This invention also efl'ects economies in the manufactureof elastic fabrics as compared with prior processes, and enables manufacturers to make these goods in relatively wide widths and later strip them into narrow widths or cut them into shapes suited to the requirements of individual uses.

While I have herein shown and described typical embodiments of my invention, it will be understood that the invention may be embodied in a great variety of forms without departing from the spirit or scope thereof. Also, that variations may be made. in the method above described within the spirit and scope of this invention.

Having thus described my invention, what'I desire to claim as new is:

1. An elastic fabric comprising a series of loosely twisted threads arranged side by side in the form of a layer and elastically held in said relationship by acoating of rubber bonded to one side of said layer, whereby said 'fabric is free to stretch in all directions except that substantially parallel to said threads, the side of said layer opposite to said coating being substantially free from said coating.

2. An elastic fabric comprising a series of loosely twisted threads arranged side by side to form a layer, and a coating of rubber on one side only of said layer to which saidthreads are adhesively united, said rubber forming the sole means for connecting said threads to each other.

3. An elastic fabric consisting of a series of parallel threads arranged side by side closely adjacent to each other-in the form of a layer and elastically held in said relationship by a foraminous coating of rubber bonded to one side only of said layer. 4 a

4. An elastic fabric comprising'a series of loosely twisted threads arranged side by side and closely adjacent to each other to form a layer, and a coating of rubber bonded to said threads at one side only of said layer and serving to secure said threads elastically to each other, said threads being free to move toward and from each other as said coating is stretched.

5. An elastic fabric comprising a series of parallel threads arranged side by side and closely adjacent to each other to form a layer, and a relatively thin sheet of rubber bonded to said threads at one side of said layer, said threads cooperating to form a substantially continuous cover for the area of said rubber sheet to which they are secured and the threads being free to 6. An elastic fabric comprising a layer of parallel threads elastically held in juxtaposition by a coating of rubber bonded to said threads at one side of said layer, said threads being free'to move of said layer, considerable areas of the latter side of the fabric being uncoated with rubber. v

7. An elastic fabric comprising a layer of parallel threads elastically held in juxtaposition by a coating of rubber bonded to said threads at one side of said layer, said threads being free to move away from each other asthe fabric is stretched, and a strip coating of rubber on the opposite side of said layer uniting the ends of said threads at ,the opposite edges ofthe fabric to said'flrst mentioned coating.

8. An elastic fabric comprisinga layer of parallel threads elastically held-in juxtaposition by a coating of rubber superficially bonded to said threads at one side only of said laye said threads being free to move away from each other as the fabric is stretched, and means for limiting the stretch of said fabric in a direction transverse to said threads. I

9. An elastic fabric comprising a series of parallel threads arranged side by side and closely adjacent to each other to form a layer, and a ioraminous coating of rubber superficially bonded to said threads at one side only of said layer and serving to secure said threads in their parallel relationship, the surfaces of said threads at the opposite side of said layer from said coating being substantially free from said coating.

10. An elastic fabric comprising a series of loosely twisted threads arranged side by side and closely adjacent to each other to form a layer, and a strip coating of rubber bonded to said threads at one side of said layer and serving to secure said threads elastically to each other, the surfaces of said threads at the opposite side of said layer from said coating being free from said coating, and said threads being free to move toward and from each other as said fabric is stretched. Y

11. An elastic fabric comprising a series of parallel threads arranged side by side closely adja-.

cent to each other to form a layer, and bands of rubber extending transversely of said threads at one side of the threads and adhesively united to said threads, said threads being free to move toward and from each other as said fabric is stretched.

12. An elastic fabric comprising a multiplicity of loosely twisted threads arranged side by side closely adjacent to each other in a layer, and a from said coating at the opposite side of said layer so that said strands can separate freely from each other as the fabric is stretched in a direction transverse to the threads.

13. An elastic fabric comprising threads arranged in parallel juxtaposed relationship to form a layer, each of said threads comprising strands loosely twisted together, and a coating of rubber onone side of saidlayer bonded to said threads and protruding sufliciently between adjacent threads to cause the stretching of the fabric to open the twist of said threads and '2 separate said strands from each other at the side of the layer opposite to said coating before adjacentthreads are separated substantially from each other.

14. An elastic fabric comprising a series of threads arranged side by side in the form of a layer and elastically held in said relationship by a coating of rubber bonded to one side of said layer and free to move toward and from each other when the-fabric is stretched, the rubber being substantially excluded from the opposite side of said layer, and lines of stitching extending transversely to said threads and serving to limit the extent to which the fabric can be stretched but permitting a substantial degree of stretch.

15. An elastic fabric comprising a series of loosely twisted parallel threads arranged in contiguous relationship in the form of a layer, and an elastic backing adhesively bonded to one side only of said layer of threads, said backing being of such weight and thickness as to permit said fabric to be stretched readily in a direction transversely of said threads.

16. An elastic fabric comprising a series of loosely twisted parallel threads arranged in contiguous relationship in the form of a layer, a coating of rubber on one side only of said layer adhesively bonded to said threads and .serving to secure said threads elastically to each other, said threads being free to move toward and from each other as said coating is stretched, and a second series of threads, approximately parallel to the first series, and bonded to the opposite side of said rubber coating. I

WARNER EUSTIS.

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