US2206808A - Tubular elastic fabric and process of making same - Google Patents

Description

July 2, 1940. R. E. DAVIS 2,206,808

TUBULAR ELASTIC FABRIC AND PROCESS OF MAKING SAME.

Filed Sept. 15, 1938 2 Sheets-Sheet l HHH E July 2, 1940. R. E. DAVIS 2,206,803

TUBULAR ELASTIC FABRIC AND PROCESS OF MAKING SAME Filed Sept. 15, 1938 2 Sheets-Sheet 2 Patented July 2, 1940 UNITED STATES PATENT OFFICE TUBULAR. ELASTIC FABaIc AND raocnss or MAKING SAME Application September 15, 1938, Serial No. 230,121

'1 Claims.

This invention relates to knitted fabrics having elastic yarn incorporated in predetermined courses of the stitches of which the fabric is composed. The invention particularly relates to ribbed fabrics with rubber, bare or covered, laid in successive or relatively spaced stitch courses between the stitch wales on one face of the fabric and the stitch wales on the opposite face thereof. The invention in its broader'aspects'however is applicable to the knitting of non-ribbed fabrics,

Knitted fabrics having rubber incorporated in the stitch courses contracts excessively in a coursewise direction, due to the fact that in drawing the rubber from its supply, such as a spool etc., the rubber is unavoidably placed under tension and is stretched thereby prior to, as, and when it is being incorporated in the fabric.

When knitted fabric is released from the knitting needles it inherently contracts to some extent when there is no rubber incorporated therein, but, when the fabric contains rubber yarn, the tension on the rubber is released with the knitting tension of the fabric and immediately contracts with and to a greater extent than the normal contraction of the fabric. This causes the fabric to be abnormally contracted.

Complicated and expensive laying-in and other rubber feeding attachments have been devised for feeding rubber into knitted fabrics under zero tension which have functioned with various degrees of success but which at the best have required constant attention to maintain in adjustment.

Manufacturers of hosiery and other tubular knitted structures in order to obtain anormally sized finished product, such as a stocking top for example, which would ordinarily be made on a three and one-half inch diameter machine and which if the fabric containedno rubber would normally contract to say about a two and onehalf inch diameter, but which when rubber is incorporated therein contracts to about a one and one-half inch diameter, have resorted to knitting the fabric on a machine of about a five inch diameter. Such a machine will produce a finished rubber-containing fabric of a normal two and one-half inch diameter. These figures are here given for the purpose of comparative illustration only and are not intended to represent any accurately calibrated actual examples.

The object of the present invention is to pro-- vide a simple process and inexpensive apparatus for laying rubber in knitted fabric or for feeding it to incorporating mechanism under positive zero or light tension, or, if desired, under longitudinal compression whereby, with the former, the fabric, after knitting, may contract only to its normally inherent extent, or, with the latter, the fabric may retain approximately the same size it obtained during knitting or be expanded coursewise, i. e. the coursewise dimension corresponding to the overall length of the needle bed or circumference of the cylinder and/or dial may be retained in the fabric with the stitch wales spaced apart laterally to the same extent as the needles, or the coursewisedimension of the fabric and the lateral spacing of the wales may be decreased, or increased, depending upon the adjustment of the simple mechanism forming the basis of the present invention.

In the accompanying drawings:

Fig. 1 diagrammatically illustrates a swatch of ribbed fabric with rubber laid. in successive courses thereof in accordance with the mind-- ples of the present invention;

Fig. 2 diagrammatically illustrates, in plan, the cylinder and dial of a, circular rib knitting machine equipped to produce the fabric of Fig. 1;

Fig. 3 diagrammatically illustrates a linear development of a portion of the cylinder and dial with the needles thereof being manipulated in accordance with the principles of the present invention to produce the fabric of-Fig. 1; and

Fig. 4 diagrammatically illustrates the cam ring and path of the butts of the cylinder needles for actuating the cylinder needles in the manner indicated in Fig. 3.

As shown in Fig. 1 the fabric F consists of successively interknit courses cl, c2, c3, c4, 05, etc. of stitches s and -sl respectively forming wales w and wl on opposite faces respectively of'the fabric.

In the present illustration, Fig. 1, there is a rubber strand R inlaid in each of the stitch courses. It will be understood that this is the result of using a' single feed circular machine such as disclosed in Figs. 2, 3 and 4 of the drawing. However, if a multiple feed machine is used there may be a rubber inlaying finger, tube, eye, etc., at each or at any desired number of such feeds, in which case the rubber R would be laid in each course or in as many relatively spaced courses as there would be rubber feeds adjacent thread feeds. For example, in a two feed machine with a rubber feed at only one thread feed the rubber R would be laid in only every alternate course, or in every third course in a three feed machine provided with a rubber feed at only one thread feed, and so on.

As shown in Figs. 2 and 3, a needle cylinder III with needles I in the grooves l2 thereof cooperates with a dial having needles 2| operating in the grooves 22 thereof.

The cylinder needles I occupy the normal rest or tuck position with the butts l3 thereof resting on a rest cam l4 in the cam ring, as shown in Fig. 4. These needles would be ordinarily raised to clearing position by a clearing cam I6. At the "high position, the needles would take the knitting yarn Y in their hooks ll whereupon the needles would be lowered to casting position by the usual stitch cam l8, to form the stitches s of the wales w.

or confined in a suitable container.

The dial needles would be actuated in the usual manner to take the knitting yarn Y in their hooks 23 from between adjacent cylinder needles I! as the latter descended in their respective grooves l2 and would be projected previously thereto and retracted concurrently with the'descent of the cylinder needles by the usual cams carried by the dial cap 24, shown in plan in Fig. 2. These cams being usual and no variation in the normal travel of the dial needles being required in carrying out the present invention, the dial needles cams in the cap 24 have been eliminated from the drawings.

In carrying out the present invention the rubber yarn R is fed to the machine at some distance ahead of the feeding of the knitting yarn Yto the needles, as shown in Fig. 2, while the cylinder needles are at rest with their hooks above the top edge H! of the cylinder ID.

The rubber R may be drawn from any suitable source such as a spool, bobbin or other package or from a loose pile lying on a suitable support No heed need be paid to the degree of tension on the strand R or the lack of tension, beyond assuring that the rubber is running freely and with a fair amount of uniformity to the needles.

The rubber strand R is fed to the cylinder needles against the outer faces 9 thereof below the hooks I1 and above the upper edge H of the cylinder l0. Due to the curvature of the cylinder the rubber R bears against the outer faces 9 of the needles II, and is laid on the top edge IQ of the cylinder, in a segment or sector R, radially beyond and concentric to the circle of the fabric F where it forms against or between the inner surface of the cylinder I0 and the outer peripheral edge of the dial 20, thus the arc of the rubber strand segment RI is of greater radius than the fabric circle, thus, a complete circle of rubber is of greater diameter than the diameter of the knitting circle of the fabric and if laid in the fabric with zero tension the rubber will tend to retain the fabric at its knitting diameter or tend to increase beyond its knitting diameter.

Normally in laying rubber in ribbed fabrics it is laid behind the cylinder needles and against the peripheral edge of the dial, which at the outset makes the diameter of a circle of the rubber, at zero tension, less than the knitting diameter of the fabric.

In order to insure zero tension on the rubber R or in order to place the rubber under longitudinal compression within the fabric, according to the present-inventiomthe rubber is drawn ,,down in successive loops or festoons L into the tops of the cylinder needle grooves .l2 by the needle hooks I! of the needles around the tbps 8 of the ribs or partitions l which are formed between adjacent needle grooves 2, as clearly shown at R2 in Figs. 2 and 3.

Where the rubber is first engaged by the hook of a needle and pulled down into a groove l2 the rubber is placed thereby under tension and this tension reacts to draw rubber from the supply. The depth to which the rubber is drawn into the top of the groove, 1. e. the length of each loop L, controls the degree of tension placed on the rubber and this in turn controls the amount of rubber drawn from the supply.

In order to keep the initial tension from reacting in the opposite direction to withdraw the rubber from the fabric a plurality of the loops L of the rubber are held down in a number of adjacent needle grooves, which snubs the rubber and prevents it from moving one way or another within the sector R2, which may be termed the holding sector.

The needles are lowered to the desired extent in the grooves |2 to draw the desired amount of rubber from the supply, by a draw cam 25, the introduction of which into the cam ring con stitutes practically the only change that is required to be .made in a normal machine in order to work the method of the present invention.

If desired, a lift cam 26 may be introduced ahead of the draw cam 25 to lift the needles slightly to insure the rubber passing below the hooks ll of the needles. This, however, in some instances at least, may be eliminated.

At the distant end of the holding sector R2 the needles H are raised by the ordinary clearing cam Hi. The raisingof the needles slacks the tension on the rubber R before it is laid in the fabric, consequently, in the sector R2, the rubber lays on the top edge I9 of the cylinder H) in a completely relaxed state, or'under any degree of tension desired depending to what extent the lower edge 25a of the. draw cam has been previously lowered with respect to the top edge Ha of the rest cam H.

The rubber R in the sector R3,relaxed as a result of the needles being raised by the clear-' ing cam IE to take the knitting yarn Y, retains its relaxed condition and lays idly on the top I9 of the cylinder ID in front of the raised cylinder needles H and under the dial needles 2|, which at this stage are projected by their own projecting or clearing cams.

As the cylinder needles I l are again lowered by the stitch cam I8 to pull the newly received knitting yarn Y through the stitches s then hanging on the shanks of these needles, and the dial needles 2| are coordinately retracted to take the knitting yarn Y and form it into loops or stitches sl by drawing it through the stitches then hanging therein, the relaxed rubber R, due to the curvature of the cylinder and dial and to the casting of the stitches and rubber over the points of the needles as the needles are lowered by the stitch cam l8, slides inwardly over and from the top I!) of the cylinder III in an inlaying sector R4, onto those portions s2 of the knitting yarn Y which connect the stitches s of the cylinder wales 10 with the stitches sl of the dial wales wl and lays in this position idly and relaxed clear around the cylinder to the feed for the yarn Y, whether it be the next feed on a multifeed machine or the same feed of a single feed machine as shown in Figs. 2 and 3.

In the meantime the cylinder needles have again been raised to the rest position by the incline Nb of the rest cam l4, this time outside the rubber R which moves the rubber R into the in-laid position, in sector R4, in the fabric between the wales w and wl. The dial needles at the same time move out to a corresponding rest position between the cylinder needles, above, the yarn R, and hold it against vertical displacement while the raised cylinder needles hold it against radial displacement.

The relaxed rubber ring lays on top of the stitch connectors s2 until the needles at the next feed of knitting yarn Y are operated and the needles, after clearing, take the yarn and form it into the stitches ofthe next course, whereupon the connectors s2 of the new course are formed over the rubber R then lying in a relaxed state on the connectors s2 of the previous course, as clearly shown at Z in Fig. 3.

From the above it will be clear that by drawing the rubber down into the, needle grooves to a greater or, lesser extent before it is laid in the fabric a suflicient amount .of the rubber R is drawn from the supply each time by each 'needle to equalize or exceed the amount of elongation of the rubber created by the tension on the rubber resulting from drawing the rubber from its supply spool, etc., thus, if equalizing amounts are drawn by the needles the rubber circle or spiral convolution thereof as laid in each course of stitches will coincide in diameter with the knitting diameter or circumference of the knitting circle of the fabric, thus the knitting circle of the fabric will be retained.

If slightly less than equalizing amount of rubber are drawn by the needles the diameter of the rubber ring will decrease somewhat below the knitting diameter of the fabric and the fabric circle will contract normally as it would inherently in cases where no rubber is inlaid in the fabric.

If excessive amounts of rubber R are drawn by the needles each time the diameter of each rubber ring or spiral convolution will exceed the knitting diameter of the fabric and the fabric will under such conditions expand coursewise to a size greater than that of the knitting diameter.

This condition, i. e. the coursewise expansion of the fabric, obviously is made possible by a walewise contraction when the pull of the drawing-ofi. rolls or the drawing-off weight, which normally places the fabric under walewise tension to effect casting of the stitches from the needles, is released. I v

The above description of the present invention has been confined to the knitting of ribbed fabrics however insofar at least as concerns the drawing of the rubber from its supply by feeding it under the hooks of a set of knitting needles, lowering the needles to'draw the rubber into loops or festoons in the needle grooves over the tops of the partitions between the grooves or the equivalent thereof, and then raising the needles successively to release the rubber in a relaxed state prior to incorporating the rubber in the fabric, the invention is equally applicable to machines for knitting plain, i. e. non-ribbed fabric on a single bank of needles, the subsequent incorporation of the rubber into the fabric as by actual knitting of the rubber itself into stitches or otherwise, in ways known to the art being merely coincidental to the preparation of the rubber for such incorporation as disclosed above.

I claim:

1. The method of placing rubber yarn in knitted fabrics, which consists in feeding the rubber under the hooks of the needles knitting the fabric while the needles are in tucking position,

successively lowering the needles to pull the rubher into the needle grooves over the tops of the partitions between said grooves to measure and form the rubberinto loops therein and thereby draw the rubber from a supply thereof, and raising the needles successively at least to said tucking position to release the rubber prior to incorporating the rubber in the fabric.

2. ,The method of placing rubber,yarn in knitted fabrics, which consists in feeding the rubber under the hooks of the needles knitting the fabric while the needles are in tucking position, successively lowering the needles to pull the rubber into the needle grooves over the tops of the partitions between said grooves to measure and form the rubber into loops therein and thereby draw the rubber from a supply thereof, holding the rubber in said loops in a plurality of said grooves,

and raising the needles successively at least to the rubber into loops therein and thereby draw the rubber from a supply thereof, holding the rubber in said loops in a plurality of said grooves,

raising theneedles successivelyat least to said tucking position to release the rubber prior to incorporatingthe rubber in the fabric, raising the needles to clearing position, feeding knitting yarn to the raised needles with the relaxed rubber in front of the needles and below the latches thereof, and lowering the needles to draw the knitting thread through loops previously formed and hanging on the needles and to cast said loops and said rubber over the points of the needles to the backs thereof.

4. The method of placing rubber yarn in knitted fabrics, which consists in feeding the rubber under the hooks of the needles knitting the fabric while the needles are in tucking position, successively lowering the needles to pull the rubber into the needle grooves over the tops of the partitions between said grooves to measure and form the rubber into loops therein and thereby draw the rubber from a supply thereof, holding the rubber in said loops in a plurality of said grooves, raising the needles successively at least to said tucking position to release the rubber prior to incorporating the rubber in the fabric, raising the needle to clearing position, feeding knitting yarn to the raised needles with the relaxed rubber in front of the needles and below the latches thereof, lowering the needles to draw the knitting thread through loops previously formed and hanging on the needle and to cast said loops and said rubber over the points of the needles to the backs thereof and knitting stitches of a succeeding course into those cast over the points of said needles with said rubber to effect incorporation of the rubber in the fabric.

5. Th method of placing rubber yarn in knitted fabrics, which consists in feeding the rubber under the hooks of the needles knitting the fabric while the needles are in tucking position, successively lowering the needles to pull the rubber into the needle grooves over the tops of the partitions between said grooves to measure and form the rubber into loops therein and thereby draw the rubber from a supply thereof, holding the rubber in said loops in a plurality of said grooves, raising the needles successively at least to said tucking position to release the rubber prior to incorporating the rubber in the fabric, raising the needle to clearing position, feeding knitting yarn to the raised needles with the relaxed rubber in front of the needles and below the latches thereof, lowering the needles to draw the knitting thread through loops previously formed and hanging on the needle and to cast said loops and said rubber over the points of the needles to the backs thereof and knitting stitches of a succeeding course by said needles into the stitches cast over the points of said needles with said rubber to eifect incorporation of the rubber in the fabric.

6. The method of placing rubber yarn in knitted fabrics, which consists in feeding the rubber under the hooks of the needles knitting the fabric while the needles are in tucking position, successively lowering the needles to pull the rubber into the needle grooves over the tops of the partitions between said grooves to measure and form the rubber into loops therein and thereby draw the rubber from a supply thereof, holding the rubber in said loops in a plurality of said grooves, raising the needles successively at least to said tucking position to release the rubber prior to incorporating the rubber in the fabric, raising the needle to clearing position, feeding knitting yarn to the raised needles with the relaxed rubber in front of the needles and below the latches thereof, lowering the needles to draw the knitting thread through loops previously formed and hanging on the needle and to cast said loops and said rubber over the points of. the needles to the backs thereof, knitting stitches of a succeeding course by said needles into the stitches cast over the points of said needles with said rubber to effect incorporation of the rubber in the fabric and operating the needles to draw and hold the rubber prior to the knitting of the stitches ofeach course on and by said needles '7. The method ofplacing rubber yarn in knitted fabrics, which consists in successively forming the rubber into a series of immediately adjacent elongated loops between relatively fixed supports for the loops to measure and place the rubber under tension and draw said rubber from a suitablesupply prior to the feeding of the rubber to the knitting point of the fabric, varying the extentof elongation of said loops to control the length of the rubber relative to the length of each course of stitches of the knitted fabric in which the rubber is incorporated for establishing a predetermined tensional relationship between the rubber and the fabric coursewise thereof and releasing said loops successively from one end of said series to relieve the rubber of said tension for delivering it in a substantially relaxed state to said knitting point.

ROBERT E. DAVIS.

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