GB2085934A - Fabric seaming - Google Patents

Abstract

A method of seaming together a pair of edges of fabric is provided including the steps of arranging the pair of edges adjacent one another so that marginal portions of the fabric containing said edges are located side by side in face to face contact, and forming a stitched seam by penetrating said marginal portions at a location spaced from said edges with at least one needle which is arranged to co-operate with a looper to form a seam, the looper being arranged to pass over said edges, the size of the stitch loops being large enough to enable the marginal portions and edges to assume a co-planar orientation when said marginal portions are pulled in opposite directions from the seam.

Description

SPECIFICATION Fabric seaming The present invention relates to seaming together a pair of edges of fabric, in particular knitted fabric, so that when the fabric is pulled in opposite directions from the seam the fabric assumes a flat orientation without an upstanding seam. The present invention is particularly applicable to seaming of the toe portion of a knitted sock to the remainder of the sock.

According to one aspect of the present invention there is provided a method of seaming together a pair of edges of fabric including the steps of arranging the pair of edges adjacent one another so that marginal portions of the fabric containing said edges are located side by side in face to face contact, and forming a stitched seam by penetrating said marginal portions at a location spaced from said edges with at least one needle which is arranged to co-operate with a looper to form a seam, the looper being arranged to pass over said edges, the size of the stitch loops being large enough to enable the marginal portions and edges to assume a co-planar orientation when said marginal portions are pulled in opposite directions from the seam.

According to another aspect of the present invention there is provided a method of seaming together a pair of edges of fabric including the steps of arranging the pair of edges adjacent one another so that marginal portions of the fabric containing said edges are located side by side in face to face contact, and forming a stitched seam by penetrating said marginal portions at a location spaced from said edges with at least a pair of needles carrying their own thread and linking the threads carried by said needles with a common looper to form a seam, the looper thread being arranged to pass over said edges, the size of the stitch loops being large enough to enable the marginal portions and edges to assume a co-planar orientation when said marginal portions are pulled in opposite directions from said seam.

If the fabric is a knitted fabric the needles are preferably arranged so that on penetration of the fabric they penetrate on different courses and on different wales of the fabric.

Accordingly when the fabric is pulled in opposite directions from the seam, the seam stitches tighten on the knitted loops of the fabric and prevent the fabric unroving.

According to another aspect of the present invention there is provided a sewing head unit for seaming together a pair of edges of fabric, the unit including a loop size control unit which, in use, is located adjacent to and on both sides of said edges, at least one needle for penetrating the fabric at location substantially below the loop size control unit and a looper arranged to co-operate with the needle either side of the fabric, the looper being arranged to rise and fall relative to the loop size control unit.

According to another aspect of the present invention there is provided a sewing head unit, particularly for use on a linking machine for linking together knitted fabric, the unit including a loop size control unit for location above the points of the linking machine at a height sufficient to enable several courses of fabric to be located above the points, at least a pair of spaced needles for penetrating fabric located on the points at a position near to the points and a looper which is arranged to collect the threads from said pair of needles after penetration of the fabric and then passes over said control unit to enable said pair of needles to pick-up thread from the looper.

According to another aspect of the present invention there is provided a linking machine for linking pieces of knitted fabric together including a sewing head unit as defined above.

The linking machine may include a preliminary sewing head for seaming together edges of fabric prior to the fabric being fed to the sewing head unit as defined above.

Reference is now made to the accompanying drawings, in which: Figure la is a schematic plan view of the toe end of a sock having a seam according to the present invention; Figure ib is a schematic cross-section through a seam according to the present invention when produced on a linking machine; Figure ic is a schematic cross-section similar to Fig. 1 b wherein the pieces of fabric have been pulled in opposite directions from the seam; Figure 2 is a schematic part perspective view of a linking machine having a sewing head unit according to the present invention; Figure 3 is a more detailed part perspective view of a sewing head unit according to the present invention; Figures 4 and 5 illustrate co-operation of the needles and looper of the sewing head unit during sewing.

Figure 6 is an illustration of the fabric after attaining the orientation shown in Fig. le Referring to Figs. 1 a and 1 b a seam 10 according to the present invention is schematically illustrated and serves to provide attachment between the toe portion 11 and the remainder of the sock 1 2.

To form a seam 10, the pieces of fabric 11, 1 2 are initially pinned on the points 21 of a linking machine 20 (Fig. 2) so that their edges 11 a, 1 2a are adjacent one another and with their faces 11 b, 1 2b facing one another as illustrated in Fig. 1 b. After sewing and pulling of the pieces of fabric in opposite directions from the seam 10, the pieces of fabric assume the orientation as illustrated in Fig. 1c As shown in Fig. 1 c, the stitches of the seam 10 are formed above and below the pieces of fabric to be joined and are sufficiently large to enable the pieces of fabric and terminal edges 11 a, 1 2a to assume a coplanar orientation when the pieces of fabric are pulled in opposite directions from the seam 10.

In order to achieve seam 10, it is necessary for the needles to penetrate the fabric at least several courses from either edges 11 a, 1 2a to ensure that the needles penetrate whole courses where unroving has not occurred. To achieve this it is necessary for the fabric to be impaled on the linking machine so that the edges 11 a, 1 2a are located several courses above the points.

The sewing head unit 25 illustrated in Fig.

2 is shown in greater detail in Fig. 3 but for the sake of simplicity the mounting frame and transmission elements for transmitting motion from the main shaft of the linking machine to the needle and looper arms have been omitted.

The sewing head unit 25 illustrated in Fig.

3 is basically a modification of a "Rosso P.R.09" sewing head and includes a needle arm 26 which is secured to a shaft 27 which is rotatably carried by a boss 28. The boss 28 forms part of the mounting frame. An actuating arm 29 is secured at one end to the shaft 27 and at the other end is connected to a push rod 30 which in turn is connected to a wheel driven by the main shaft of the linking machine. The push rod 30 is arranged to oscillate the shaft 27 about its axis thereby causing oscillation of the needle arm 26. The needle arm 26 carries a pair of needles 32a, 32b which are spaced from one another in the direction of movement of the points 21 and also in height above the points 21.

The needles 32a, 32b are secured to the needle arm 26 by means of a clamping plate 26a which is secured to the arm 26 by means of a screw 26b (Fig. 4). The butts of needles 32a, 32b are clamped between the clamping plate 26a and needle arm 26, the butt of needle 32a being provided with flats either side of the butt in order to facilitate correct positioning of the needles.

The needles 32a, 32b co-operate with a looper 40 in order to produce stitches for forming seam 10. The looper includes a looper arm 41 which is fixedly mounted at one end to a shaft 42 which is rotatably housed in a sleeve 43. The sleeve 43 is located within a bush 44 and its axial movement is prevented therein by means of a screw 46. The screw 46 may be released to enable height adjustment of the sleeve 43 and looper arm 41.

The upper end of shaft 42 is provided with an actuating arm 47 which has a depending portion 47a pivotally connected to a push rod 49. The push rod 49 is connected to a wheel (not shown) driven by the main shaft of the linking machine and is oscillated thereby. Accordingly shaft 42 is caused to oscillate about its axis thereby causing oscillation of the looper arm 41. A spring 50 is positioned between acutating arm 47 and the upper end of sleeve 43 so that the shaft 42 is urged upwardly to bias the looper arm 41 into contact with the lower face of sleeve 43. The lower face of sleeve 43 is inclined to form a cam face 43a and a projection 52, preferably in the form of a ball bearing received in a cup formed in the looper arm 41, is provided as a cam follower so that as the looper arm 41 is oscillated it is also caused to rise and fall with respect to the points.This enables the looper needle 55 which is carried by the looper arm 41 to pick-up yarn from the pair of needles 32a, 32b which penetrates the fabric on the points at a position just above the points and then rise to a sufficient height above the loop size control unit 60 to pass over the fabric and unit 60 to co-operate with the needles 32a, 32b prior to their return motion to penetrate the fabric. Accordingly, it is possible to impale fabric 11, 1 2 on the points so that edges 11 a, 1 2a are sufficiently high above the points to ensure that enough courses are above the points to enable the needles to penetrate complete courses located near to the points.

The unit 60 determines the loop size of the stitches formed by the needles and loopers and as shown in the insert the unit 60 includes a pair of fingers 60a, 60bwhich are spaced from one another. In use, the edges 11 a, 1 2a of the fabrics to be joined are fed between the fingers 60a, 60b so that during formation of the sewn loops the edges of the fabrics are completely isolated from any drag so that after sewing the sewn stitches and knitted fabric leave the fingers 60a, 60b in a relaxed state. Finger 60a is provided with a depending flange 60cwhich is inclined downwardly so that, if necessary, it can assist in deflecting the looper needle over the fingers 60a, 60b.

Figs. 4 and 5 illustrate various positions of the needles and looper needle during sewing.

In Fig. 4 the needles 32a, 32b are about to penetrate fabric on the points 21 at a position below member 60. The looper needle is retracting from an advanced position and is in a raised position to clear the unit 60.

In Fig. 5 the needles 32a, 32b have attained their fully extended positions and are about to retract. The looper needle has moved to its lowermost position and is about to advance to pick up the threads from both needles 32a, 32b.

It will be appreciated that the rise and fall of the looper may be achieved in different ways, for instance by providing a projection on shaft 42 and an inclined slot in sleeve 43 for receiving the projection.

In Fig. 6 a piece of fabric 1 2 is shown wherein the stitches formed by the needles are shown at 70 and those formed by the looper at 71. Since the needles penetrate at different courses and different wales the needles produce a chain stitch extending along a pair of courses of the fabric, the chain stitch of one needle being offset from that of the other. Additionally, the chain stitches of both needles are linked by a common looper thread 71 so that when the looper thread and needle threads are pulled, as during the pulling of the fabric in opposite directions from the seam 10, then the threads tighten about the intervening knitted loops of the fabric thereby resisting any unroving tendency of the fabric.

In certain circumstances it may be desired to compliment the seams by sewing edges 11 a, 1 2a to one another by a conventional over sewing operation prior to feeding the fabric to the sewing head unit 25. Accordingly the linking machine may be provided with two sewing stations, a first station for providing an oversewn seam connecting the edges of the fabrics to be joined and a second sewing station for producing a seam 10 as described above.

The above description has related to the seaming together of knitted fabrics wherein we prefer to use two needles for forming the seam. It is envisaged however that for certain fabrics, such as woven fabrics, the seam may be adequately formed using a single needle co-operating with the looper. Additionally such a seam formed by a single needle could be used for seaming knitted fabrics particu lariy if the edges were first seamed together by a conventional over sewing operation as mentioned above.

Claims (9)

1. A method of seaming together a pair of edges of fabric including the steps of arranging the pair of edges adjacent one another so that marginal portions of the fabric containing said edges are located side by side in face to face contact, and forming a stitched seam by penetrating said marginal portions at a location spaced from said edges with at least one needle which is arranged to co-operate with a looper to form a seam, the looper being arranged to pass over said edges, the size of the stitch loops being large enough to enable the marginal portions and edges to assume a co-planar orientation when said marginal portions are pulled in opposite directions from the seam.

2. A method of seaming together a pair of edges of fabric including the steps of arranging the pair of edges adjacent one another so that marginal portions of the fabric containing said edges are located side by side in face to face contact, and forming a stitched seam by penetrating said marginal portions at a location spaced from said edges with at least a pair of needles carrying their own thread and linking the threads carried by said needles with a common looper to form a seam, the looper thread being arranged to pass over said edges, the size of the stitch loops being large enough to enable the marginal portions and edges to assume a co-planar orientation when said marginal portions are pulled in opposite directions from said seam.

3. A method according to Claim 2 wherein for the seaming of knitted fabric, the seam stitches are formed so as to tighten on the knitted loops of the fabric to prevent the fabric unroving.

4. A method for seaming of fabrics substantially as herein described with reference to any of the accompanying drawings.

5. A sewing head unit for use on a linking machine, the unit including a loop size control unit for location above the points of the linking machine at a height sufficient to enable several courses of fabric to be located above the points, at least a pair of spaced needles for penetrating fabric located on the points at a position near to the points and a looper which is arranged to collect the threads from said pair of needles after penetration of the fabric and then passes over said control unit to enable said pair of needles to pick-up thread from the looper.

6. A sewing head unit according to Claim 1, wherein the looper includes a needle mounted for oscillatory motion radially of said points, the needle also being mounted so that during said oscillatory motion it oscillates from a position below to a position above said control unit.

7. A sewing head unit according to Claims 5 or 6 wherein the loop size control unit includes a pair of spaced fingers which in use are located either side of the edges of the fabric to be joined.

8. A sewing head unit for seaming together a pair of edges of fabric, the unit including a loop size control unit which, in use, is located adjacent to and on both sides of said edges, at least one needle for penetrating the fabric at location substantially below the loop size control unit and a looper arranged to cooperate with the needle either side of the fabric, the looper being arranged to rise and fall relative to the loop size control unit.

9. A sewing head unit substantially as described with reference to and as illustrated in any of Figs. 2, 3 to 5 of the accompanying drawings.

1 0. A hose having a foot portion including a seam created by a method according to any of claims 1 to 4.