US3646780A

US3646780A - Apparatus and method for making a stitch-bonded fabric

Info

Publication number: US3646780A
Application number: US867331A
Authority: US
Inventors: Arno Edgar Wildeman
Original assignee: Cosmopolitan Textile Co Ltd
Current assignee: Cosmopolitan Textile Co Ltd
Priority date: 1968-10-19
Filing date: 1969-10-17
Publication date: 1972-03-07
Anticipated expiration: 1989-03-07
Also published as: BE740368A; ZA697260B; GB1268630A; FR2021097A1; NL158860B; NL6915712A; DE1952558B2; DE1952558A1; DE1952558C3

Abstract

Method and apparatus for the production of a stitch-bonded fabric in which the stitches are locked by the formation of tufts or loops of fiber which are interlocked into the stitches of thread produced by the reciprocation of a series of tubular or slide needles. The invention also provides timing of the movements of the slide or tubular needles relative to the movements of the closing wires or rods for these needles and to the control of the distance moved by the needles and the closing wires or rods so that the wires or rods do not penetrate the fibrous batt completely and the degree of penetration of the needles is controlled to prevent the creation of voids in the batt which will prevent the formation of fiber loops when the needles are retracted to form stitches.

Description

United States Patent Wildeman 1 Mar. 7, 1972 [72] lnventorz Arno Edgar Wildeman, Bowdon, England [73] Assignee: Cosmopolitan Textile Company Limited,

Chester, England [22] Filed: Oct. 17,1969

[21] Appl.No.: 867,331

FOREIGN PATENTS OR APPLICATIONS 268,231 6/1966 Australia ..66/85A 1,495,184 8/1967 France ..66/85A Primary ExaminerRobert R. Mackey Anorney-James E. Nilles [57] ABSTRACT Method and apparatus for the production of a stitch-bonded fabric in which the stitches are locked by the formation of tufts or loops of fiber which are interlocked into the stitches of thread produced by the reciprocation of a series of tubular or slide needles. The invention also provides timing of the movements of the slide or tubular needles relative to the movements of the closing wires or rods for these needles and to the control of the distance moved by the needles and the closing wires or rods so that the wires or rods do not penetrate the fibrous batt completely and the degree of penetration of the needles is controlled to prevent the creation of voids in the batt which will prevent the formation of fiber loops when the needles are retracted to form stitches.

4 Claims, 7 Drawing Figures PATENTED R 7 i972 SHEET 2 [1F 4 PATENTEUMAR H912 3 646,780

SHEET 3 [IF 4 INVENTOR: A E. W/LDf/Wfi N APPARATUS AND METHOD FOR MAKING A STITCH- BONDED FABRIC BACKGROUND OF THE INVENTION This invention concerns nonwoven fabrics and in particular a nonwoven fabric in which lines of stitches are provided to assist in the consolidation and reinforcement of a nonwoven web or fleece. Such fabrics have recently become known as stitch-bonded fabrics which term will be used in this specification to describe the fabric to which reference is made.

Basically a stitch-bonded fabric is produced by the provision, in a fleece lap, of a multitude of longitudinal rows of seams. This type of fabric has the disadvantage that the seams, which are produced by the use of, for example, a series of slide or tubular needles, are capable of being easily pulled out from one end or from a break in the stitching yarn, since the stitch formation of each row consists essentially of a series of interengaged loops.

According to the present invention there is provided a stitch-bonded fabric in which the stitches of each longitudinal row of seams are locked against removal by causing fibers anchored in the fleece to become interengaged with the stitch loops.

The invention will now be described further by way of example, with reference to the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a part sectional view of the stitch forming mechanisms of a machine made in accordance with the invention;

FIGS. 2 to 5 are sectional views of part of the stitch-forming mechanism of the machine of FIG. 1 showing one stitch-forming cycle of the machine;

FIG. 6 is an enlarged, somewhat schematic part sectional view of part of a needle showing the effects of various degrees DESCRIPTION OF A PREFERRED EMBODIMENT In the following description no reference will be made to the formation of the fleece since this can be produced in any one of a series of well-known methods.

To produce a stitch-bonded fabric in accordance with the invention a fleece 10 is passed through a knitting machine which incorporates a row of slide needles 11 (that is needles having on one edge a groove 12 in which a wire rod 13 can slide to open and close a hook formation 14 at the needle point). Alternatively tubular needles may be used in which a wire rod slides in or through a hole in the needle to close the hook formation, which would be a minor variation.

The slide needles 11 are mounted upon a carrier bar 15 which is reciprocable towards and away from the fleece 10 to cause penetration and retraction of the needles through the fleece.

Mounted above the carrier bar 15 and adapted to carry the wire rods 13 is a rod mounting rail 16 which is also reciprocable towards and away from the fleece 10. The reciprocation of the mounting rail is controlled independently of but in timed relationship with the carrier bar.

It is important to note that the uppermost face 14a of the hook formation 14 lies in the same plane as the lowermost point of the groove 12 of the needle 11 so that, when required in the cycle of operations (to be described below) the rods 13 can overlie the hook formations 14 to close the hook.

Mounted forwardly (relative to the fleece 10) of the carrier bar 15 and in fixed condition is a holding member 17. The holding member 17 is conveniently secured to a part 18 of the machine frame. Projecting upwardly from the holding member 17 and spaced to allow passage of the needles ll therebetween is a series of fleece guide arms 19 the free ends of which are connected to a tie bar 20, which extends across the working width of the machine. The tie bar 20, arms 19 and the front face 17:: of the holding member 17 to serve collectively as afleece and fabric guide against which the rear face" of the fleece and the just-formed fabric passes when the machine is in operation. In addition to guiding the fleece and fabric, the fleece and fabric guide serves to retain the fleece and fabric against movement with the needles during their retraction from the fleece.

Spaced from the arms 19 are a series of support pins 21, there being a support pin in alignment with each arm 19. The support pins 21 are carried at their lower ends in a groove 22 formed by a front support rail 23 and a cloth retention bay 24 with a step 24a on its leading edge defining a restricted throat for the fleece. The two

elements

23, 24 are secured together by studs or the like (not shown). Alternatively, a unitary grooved rail may be provided to replace the elements 23. 24, the pins being seated in the groove. At a position below the needles 11 the two bars are angled away from the front face 17a of the holding member 17. The pins 21 at their upper ends are mounted in a beam 25 which extends across the working width of the machine. The beam 25 and pins 21 collectively form a fleece guide and that part of the cloth retention bar 24 which lies parallel to the face 17a of the holding member 17 forms a cloth guide for the front face of the cloth. It will be appreciated that, by virtue of the construction and disposition of the

elements

20, 19 and 17 relative to the

elements

25, 21 and 24 the fleece and cloth is, as it is moved in the direction of arrow F, constrained between the fleece guides and the cloth retention bar 24.

Spaced from the front bar 23 at the side remote from the needles 11 and at the level of the needles are a series of thread guides 26 each having an eye 27 through which the threads pass. There is of course a thread guide 26 for each needle 11. The thread guides 26 are carried by a rail 28. Threads 29 are passed through the eye 27 of each thread guide 26. The rail 28 and thus the thread guides 26 are adapted to reciprocate transversely of the machine with a slight rise and fall so that a thread 29 can be laid in the hook of each needle I 1.

A cycle of operations will now be described with reference to FIGS. 2 to 5 which show the formation of a first stitch in a fleece. The threads 29 are held at their free ends 29a and with the needles 11 at their extreme forward position (in which they have completely penetrated the fleece ll arid in which the hook ends 14 lie in front of the guide pins 21) the threads 29 are laid in the hooks of the pins 11. In this position of the needles 11 the wires 13 have their extreme ends adjacent the guide needles 21 but within the fleece thickness. As can be seen from FIGS. 2 to 5 in particular the fleece is retained by the pins 21 against movement with the needles 11 during their insertion into the fleece.

The initial movement of the needles 11 is rearwardly in the direction of arrow N to cause the needle hooks 14 to be retracted into the fleece in such manner that before the hook end of each needle 11 is closed by a rod 13 a bunch 30 of fibers of the fleece are entrained by the needle hooks 14 (see FIG. 3), which fibers lie in the path of the hooks 14 by reasons of the inherent resiliency of the fleece. This is aided by the compression applied to the fleece at step 24a of the cloth retention bar 24 below the needles 1!.

As the needles 11 continue their rearward movement the rods 13 close the hook ends 14 and when this has occurred the rods 13 are retracted in the direction of arrow R in unison with the needles until the needles I1 and rods 13 are located rearwardly of the arms 19. At this point in the cycle a loop 31 of thread 29 has been formed through the fleece and additionally a loop of fibers (formed by the bunch 30) has also been formed by fibers drawn effectively from the front face of the fleece (See FIG. 4).

At this point in the cycle, the fleece with its loop of thread is moved in the direction of the arrow F, that is in the take up direction. When the requisite movement is completed the needles 11 are moved forwardly and the rods 13 remain stationaryv The forward movement of the needles in the direction of arrow N opens the needle hook 14 thus enabling the loops 31 of yarn 29 and the looped bunch of fibers 30 to be pushed onto the shank of the needles 11 by the resistance to forward movement of the yarn and the fiber loop by the fabric. The rods 13 now commence their forward movement in the direction of arrow R (See FIG. 5), which movement continues until the tips of the rods 13 reach the position shown in FIGS. 2 and 5. The needles 11 continue their forward movement until they reach the position shown in FIGS. 2 and 5 at which time the thread guides are reciprocated to lay the threads 29 across the needle hooks 14. The cycle is then repeated and as the needles 11 and rods 13 are approaching the limit of their rearward motion in unison, the new loops of thread 31 and the new bunches of fibers 30 are drawn through the previously formed loops to form a new loop stitch.

Reference to FIG. 6 shows that the number of fibers used to form the loop 30 depends upon the number of fibers contained within a triangular area bounded by that part of the bottom edge 13a of the rod 13 which projects slightly from the end of the groove 12, the outside face of the fleece l0 and the angular face 14b of the needle hook 14. In FIG. 6 the line 10a representing the outside face of the fleece is shown in one position relative to the tip of the rod 13 and the lines F and F show respectively the effect on the triangular area of causing the needle to extend to a greater or lesser extent beyond the face of the fleece.

As can be seen if the needle is made to penetrate through the fleece to a relatively large extent the area of the triangle will be small and few fibers will be available to form a loop 30. On the other hand if penetration of the needle is to a lesser degree there will be a greater number of fibers available to form the loop 30. The degree of penetration of the needles is adjustable and thus the requirements of manufacturers of stitch-bonded fabric can be met. It should be appreciated that the through penetration of the needle hook must not be so great as to result in the tip of the rod 13 extending beyond the face of the fleece nor in fact so great as to cause the needle to have penetrated to an extent such that a void will be created in the fibers of the fleece. Such a void would be created if the needle were caused to penetrate to such an extent that the whole of the angular face 14b were to extend beyond the face of the fleece since the fibers of the fleece would be opened to the full height H of the needle and as shown in FIG. 7 upon retraction of the needle in the direction of arrow N the hook end would enter the void V which, due to the difference in height H between the needle shank and the height H at the tip of the hook end, would result in no fibers being collected by the needle hook.

It is found that, due to the formation of fiber loops in conjunction with thread loops, the threads cannot now be withdrawn from either end or from a break due to the locking action of the loops of fibers and thus the disadvantage of the prior art stitch bonded fabrics is overcome in a simple and effective manner which does not require the provision of any more yarn than was previously required.

The size of the stitches can be varied as can the spacing between the rows of stitches.

lclaim:

l. The method of producing a stitch-bonded fabric having fleece and fibers, said method including the steps of reciprocating a series of needles through a fleece, while progressing the fleece successively between each successive needle insertion,.halting a rod or wire associated with each needle within the fleece, halting the needles after penetration of the fleece and before they have penetrated to an extent such that the greatest height of needle has passed through the fleece, laying a thread over the hook of each needle, retracting the needles to draw the threads through the fleece in the form of loops, and simultaneously to collect by the inherent resiliency of the fleece a bundle of fibers from the region of the face of the fleece from which the needle hooks have projected, closing the hooks of the needles by the wires or rods to retain the threads and the fiber bunches in the needle hooks,

retracting the needles together with said collected fibers and thread in said hooks, opening the needle hooks after retraction of the needles from the fleece, moving the needles into the fleece after progressing the latter in the take up direction thus to cause the threads and the fibers to lie on the shanks of the needles, halting the wires or rods within the fleece and projecting the needles through the fleece, laying further loops of thread on the needles and repeating the cycle continuously to produce lines of fiber-locked interengaged stitches of thread to produce a fabric.

2. The method set forth in claim 1 including the step of halting the retraction of said needles outside said fleece, and also retracting said wires to open the hooks of said needles, and when said needles again commence forward movement, the loops of thread and fibers from the hooks are transferred to the shanks of said needles for interengagement with subsequent loops of thread and fiber.

3. Apparatus for producing a stitch-bonded fabric having a plurality of longitudinal rows of stitched seams and in which the stitches are locked against removal by causing fibers anchored in the fleece to become interengaged with the loops of the stitches, said apparatus comprising a series of needles arranged to penetrate a fleece, hooks on said needles, said hooks having an inclined surface, a hook-closing wire for each needle, thread guides for laying threads across the hooks of said needles, means for moving said needles collectively to reciprocate such as to penetrate through and retract from said fleece, independent means collectively to reciprocate said hook-closing wires in synchronism with said needles and to limit the stroke of said wires to cause entry into but not penetration through said fleece and not sufficiently to cover said inclined surface, and to retract said wires, whereby said hook ends of said needles may be provided with threads from said thread guides and, upon retraction may collect in said hook a loop of fibers from said fleece to draw same together with said yarn through said fleece and cause interengagement of loops of thread and interlocking of said loops with loops of fibers, and a cloth retention bar below said needles defining a restricted throat for the fleece.

4. Apparatus as set forth in claim 3 including, spaced fleece guides between which said fleece may pass, spaced members on said fleece guides between which said needles and said wires may reciprocate, and fabric guides associated with said fleece guides and below said spaced members of said fleece guides between which a fabric formed by the production of stitches therein may pass, said fleece guides and said fabric guides collectively constraining said fleece and said fabric from movement with said needles during insertion and retraction thus to enable correct formation and tightening of stitches of thread and loops of fiber to be achieved.

Claims

1. The method of producing a stitch-bonded fabric having fleece and fibers, said method including the steps of reciprocating a series of needles through a fleece, while progressing the fleece successively between each successive needle insertion, halting a rod or wire associated with each needle within the fleece, halting the needles after penetration of the fleece and before they have penetrated to an extent such that the greatest height of needle has passed through the fleece, laying a thread over the hook of each needle, retracting the needles to draw the threads through the fleece in the form of loops, and simultaneously to collect by the inherent resiliency of the fleece a bundle of fibers from the region of the face of the fleece from which the needle hooks have projected, closing the hooks of the needles by the wires or rods to retain the threads and the fiber bunches in the needle hooks, retracting the needles together with said collected fibers and thread in said hooks, opening the needle hooks after retraction of the needles from the fleece, moving the needles into the fleece after progressing the latter in the take up direction thus to cause the threads and the fibers to lie on the shanks of the needles, halting the wires or rods within the fleece and projecting the needles through the fleece, laying further loops of thread on the needles and repeating the cycle continuously to produce lines of fiber-locked interengaged stitches of thread to produce a fabric.