APPARATUS FOR PRODUCING A SEAM

Abstract: A method of seaming together two or more pieces (10) (12) of fabric wherein the edges (11) (13) of the pieces of fabric are initially seamed together by one or more rows of ordinary chain stitches (16) (17) and thereafter the joined edges are oversewed by at least one pair of independent rows of over­ sew chain stitches (18) (19), one row of stitches of said pair being formed so that its loops (18a) are located on one side of the finished seam and the other row of stitches (19a) of said pair being formed so that its loops are located on the other side of the finished seam.

Description: METHOD AND APPARATUS FOR PRODUCING A SEAM The present invention relates to a method and apparatus for producing a seam for joining two or more pieces of fabric together and to a seam produced thereby. ' It is a general aim of the present invention to provide a seam for joining edges of knitted fabric which are not selvedged as encounted when producing garments by cutting and sewing together pieces of knitted fabric. According to one aspect of the invention there is provided a method of seaming together two or more pieces of fabric wherein the edges of the pieces of fabric are initially seamed together by one or more rows of ordinary chain stitches and thereafter the joined edges are oversewed by at least one pair of independent rows of oversew chain stitches, one row of stitches of said pair being formed so that its loops are located on one side of the finished seam and the other row of stitches of said pair being formed so that its loops are located on the other side of the finished seam. According to another aspect of the invention there is provided a linking machine for performing the method as defined above including a dial of points, a first sewing station for producing said ordinary chain stitches and a second sewing station for producing said at least one pair of oversew chain stitches, said second sewing station including a first stitching assembly and a second stitching assembly spaced from one another in the direction of indexing of the dial of points, each stitching assembly having a needle and co-operating yarn wrapper for supplying yarn to the needle, the needle of one assembly being located on the inside of the dial and its co-operating yarn wrapper being arranged on the outside of the dial and the needle of the other assembly being located on the outside of the dial and its co-operating yarn wrapper being located on the inside of the dial. According to another aspect of the invention there is provided a seam for joining two or more pieces of fabric including one or more rows ot ordinary chain stitches and at least one pair of oversew chain stitches, one row of stitches of said pair being formed so that its loops are located on one side of the finished seam and the other row of stitches of said pair being formed so that its loops are located on the other side of the finished seam. Reference is now made to the accompanying drawlngs, in which: Figure 1 is a schematic, part perspective view of a seam according to the present invention; and Figure 2 is a part perspective view of a linking machine adapted to produce a seam according to the present invention. Referring initially to Figure 1 there is shown two pieces of knitted fabric 10, 12 which are joined together by a seam 15. The pieces of fabric 10, 12 have raw edges 11, 13 respectively which are secured and protected by the seam 15. The seam 15 is composed of four independent rows of stitches 16, 17, 18 and 19. Rows 16, 17 are ordinary chain stitches, each row of stitches being formed from a single thread 16 a manner similar to that disclosed in our U.K. Patents 1566771, 1520637 and 1506575. Reference should be made to these patents as the disclosure therein is assumed to be incorporated in this specification. The rows of stitches 18 and 19 are oversew stitches formed from independent single threads 20, 21 respectively. Unlike the oversew stitches in our previously mentioned patents, one row of stitches is formed so that the loops 18a thereof are located on one side of the seam 15 and the other row of stitches is formed so that the loops 19a thereof are located on the other side of the seam 15. Penetration of the stitches 18, through the fabric pieces 10, 12 alternate with that of stitches 19 at spacings equal to the indexing spacing of the dial of points of the linking machine. Forming the oversew stitches in the manner described above with reference to Figure 1 has two main advantages over known seams. The first advantage is that the seam 15 according to the present invention tends to be unbiased i.e. tensions within stitches 18, 19 are balanced on either side of the seam giving the result that the seam tends to be even and straight thereby giving an aesthetically superior seam. A second advantage is that the present seam is softer than convention oversew seams. In oversew seams where the oversew stitches are formed from one side of the fabric only the bulk of the loops on one side of the seam tend to rigidify the seam and so resist compression. This can be a disadvantage in clothing as it can result in making the article of clothing uncomfortable to wear. This disadvantage is overcome by the present seam. Reference is now made to Figure 2 wherein part of a linking machine 30 is illustrated in perspective. Reference should be made to the previously mentioned patents, in particular U.K. Patent 1520637, since the linking machine 30 illustrated in Figure 2 is a modification of the linking machine disclosed in U.K. patent 1520637. Accordingly the present linking machine 30 includes a first sewing station (not shown) for producing rows of stitches 16, 17 and a cuttlng station (not shown) for trimming the edges of the fabrics prior to them being presented to the oversew station 31 shown in Figure 2. The sewing station 31 includes a first stitching assembly 32 which has a needle arm 33 pivotally connected to a pivoted lever 34 which is pivotally connected to the machine frame by a bearing 34a. The needle arm 33 carries a needle 36 which co-operates with a yarn wrapper 35. The needle arm 33 is located on the inside of the dial of points 42 and is reciprocally deflected by a push rod assembly (not shown) located within housing 38 so as to reciprocate the needle 36 towards and away from the yarn wrapper 35 which is located outside the dial of points 42. When the needle 36 is in the vicinity of the yarn wrapper 35, yarn (not shown) is wrapped about the needle 36 which on withdrawing trom the yarn wrapper 35 draws fresh yarn and casts off the previously drawn loop. The lever 34 is reciprocally deflected by a push rod 40 in timed relationship to the advancement stroke of the needle 34 towards the yarn wrapper 35 so that on alternate advancement strokes the needle is in a lower position to penetrate fabric (not shown) on the dial of points 42 and on the next advancement stroke is in a raised position to pass over the edge of the fabric on the points Height displacement of the lever 34 is achieved by providing a slot 34b which enables the point of attachment of the push rod to be moved relative to the axis of bearing 34a. Rotary drive to yarn wrapper 35 is conveniently provided by continuous belts 45, 46 and shaft 47 rotatably mounted on housing 38. Belt 45 is driven by a pulley 49 which is driven by the main drive shaft of the machine. The second stitching assembly 50 is located at a predetermined spacing in the direction of indexing of the dial of points and includes a needle arm 33' having a needle 36' co-operating with a yarn wrapper 35'. The needle arm 36' is located outside the dial of points 42 and the yarn wrapper 35' is located inside the dial of points 42. The needle arm 33' is conveniently mounted on the lever 34 also and is arranged to advance and retract from its co-operatlng wrapper in synchronism with needle arm 33. It is envisaged that the first sewing station may be arranged so that penetration of a first needle for forming one of the rows of ordinary chain stitches is from one side of the fabric and that penetration of a second needle for forming the other of the rows of ordinary chain stitches is from the other side of the fabric. In this way the bulk of yarns on either side of the seam is the same. A constructional arrangement of a suitable sewing station is disclosed in our U.K. patent 1592198 and reference should be made thereto.

Claims: CLAIMS 1. A method of seaming together two or more pieces of fabric wherein the edges of the pieces of fabric are initially seamed together by one or more rows of ordinary chain stitches and thereafter the joined edges are oversewed by at least one pair of independent rows of oversew chain stitches, one row of stitches of said pair being formed so that its loops are located on one side of the finished seam and the other row of stitches of said pair being formed so that its loops are located on the other side of the finished seam. 2. A method according to Claim 1 wherein said one row of stitches and said other row of stitches forming said pair are formed in synchronism so that the same stitch operations are performed at the same time but on opposite sides of the finished seam. 3. A linking machine for performing the method according to Claim 1 including a dial of points, a first sewing station for producing said ordinary chain stitches and a second sewing station for producing said at least one pair of oversew chain stitches, said second sewing station including a first stitching assembly and a second stitching assembly spaced from one another in the direction of indexing of the dial of points, each stitching assembly having a needle and co-operating yarn wrapper for supplylng yarn to the needle, the needle of one assembly being located on the inside of the dial and its co-operating yarn wrapper being arranged on the outside of the dial and the needle of the other assembly being located on the outside of the dial and its co-operating needle being located on the inside of the dial. 4. A linking machine according to Claim 3 wherein the needles for each assembly are mounted on a needle arm, which is pivotally connected to a pivoted lever for reciprocally raising and lowering the needle arm. 5. A linking machine according to Claim 4 wherein the needle arms for both assemblies are mounted on a common pivoted lever. 6. A seam for joining two or more pieces of fabric including one or more rows of ordinary chain stitches and at least one pair of oversew chain stitches, ode row of stitches of said pair being formed so that its loops are located on one side of the finished seam and the other row of stitches of said pair being formed so that its loops are located on the other side of the finished seam.

Inventors: MATTHEWS, DENIS
Applicants: MATHBIRK LIMITED
Application year: 1983
Main classification: D05B1
IPC codes: D05B1, D05B7