A linking machine

Abstract

 A fabric trimming device comprising a movable blade member (34) in slidable face to face contact with a fixed blade member (37), the movable blade member and fixed blade member having co-operating blade edges (46)(47) for cutting fabric located therebetween on reciprocation of said movable blade member relative to said fixed blade, non resilient bearing means (41) for maintaining face to face contact between the movable and fixed blade members

Description

[0001] The present invention relates to a linking machine.

[0002] A linking machine normally comprises a dial of points on which fabric to be joined is impaled. The fabric is conveyed by the points to a first sewing station to a trimming station whereat excess fabric is removed and then to second sewing station whereat the joined edges of the fabrics is oversewn.

[0003] The present invention is particularly concerned with a linking machine having an improved trimming device and also a linking machine having an improved oversew station.

[0004] According to one aspect of the present invention there is provided a fabric trimming device comprising a movable blade member in slidable face to face contact with a fixed blade member, the movable blade member and fixed blade member having co-operating blade edges for cutting fabric located therebetween on reciprocation of said movable blade member relative to said fixed blade, non-resilient bearing means for maintaining face to face contact betwen the movable and fixed blade members. Preferably the non resilient bearing means comprises at least one roller bearing which contacts the movable blade member.

[0005] According to another aspect of the present invention there is provided a stitch forming device for use with an oversew needle, the device including a pair of fingers which are spaced apart to define a gap through which fabric to be oversewn can be fed, the fingers being arranged to extend along either side of the fabric and having an upper edge located between the edge of the fabric in the region of stitch formation of the oversew needle such that during formation of the stitch loop it lays directly on the upper side of the fabric to be oversewn. Preferably one of the fingers is rigid and the other is resilient so that the fabric is resiliently gripped between the fingers as it is advanced along said gap.

[0006] Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which:-

Figure 1 is a schematic perspective view of a linking machine according to the present invention;

Figure 2 is a perspective view of a trimming device according to the present invention:

Figure 3 is a plan view of the trimming device shown in Figure 2;

Figure 4 is a sectional view taken along line IV-IV in Figure 3;

Figure 5 is a schematic illustration of a linking process formed on a linking machine according to the present invention.

Figure 6 is a side view of a stitch forming device according to the present invention; and

Figure 7 is a plan view of the stitch forming device illustrated in Figure 6.

[0007] Referring initially to Figures 1 to 4 there is shown a linking machine 10 having a dial of points 15 on which fabric pieces to be joined are impaled. The dial of points 15 is rotatable relative to a base 16 and serves to move the impaled fabric in succession from a first sewing station 18 to a trimming station 20 and then to a second sewing station 22.

[0008] The linking process is schematically illlustrated in Figure 5 wherein the direction of movement of the dial of points 15 is represented by arrow A. A first seam 23 for joining the fabrics F together is produced at sewing station 18 and then excess fabric EF above the seam 23 is then removed by the trimming device 18. An oversew seam 24 is finally produced at station 22.

[0009] A first sewing station has a pair of needles 19 which produce the seam 23 just above the points 15. The first sewing station 18 is of a conventional construction such as for example as described in our UK Patent 1520637

[0010] The trimming device 18 for removing the excess fabric EF is illustrated in greater detail in Figures 2 to 4.

[0011] The trimming device 18 includes a main body 30 having a central opening 32 which divides the body 30 into a pair of body portions 31. The body 30 is mounted on the base 16 such that the central opening 32 is positioned above the points 15 such that on rotation of the dial of points 15 the portion of the fabric located above the points is fed into the lower portion of the central opening 32.

[0012] Each body portion 31 is provided with a groove 33 in its lover face and a movable blade member 34 is slidably received therein. The grooves 33 serve to guide reciprocal movement of the blade 34. A static blade member 37 is secured to the lower face of one of the body portions 31 and a plate member 38 is secured to the lower face of the other body portion 31. The blade member 34 is thereby held captive within grooves 33.

[0013] A bearing member 39 is located within a bearing cavity 40 formed in each body portion 31 and is arranged to contact the upper surfaces of the movable blade member 34. Each bearing member 39 is adjustably mounted within its body portion 31 such that tolerances between the bearing member 39, the blade member 34 and the static blade member 37 and plate member 38 can be reduced to a desired minimum. In this way, the blade member 34 is maintained in face to face contact with the blade member 37 and plate member 38 without pressure contact but cannot lift therefrom.

[0014] In the illustrated embodiment each bearing member 39 is in the form of a roller bearing 41 which is mounted on an eccentric portion of a shaft 42. The shaft 42 projects from one side of the respective body portion 31 to provide access to the shaft. The shaft may therefore be engaged to cause its rotation and thereby move the bearing 41 toward or away from the blade 34.

[0015] The blade member 34 is provided with a blade edge 46 which extends obliquely across the width of the blade member 34 such that as the blade edge 46 moves toward the blade edge 47 of the static blade it defines a cutting point which sweeps along both blade edges in a direction opposed to the direction of feed of the fabric by the dial of points.

[0016] Preferably the static blade 37 has an additional blade edges 47′ and is detachably mounted on the respective body portion 31 so that it may be removed and inverted to present a fresh blade edge for co-operation with blade member 34. It will be appreciated that when both blade edges 47 have become dull that it is possible to re-sharpen the edges by a surface grinding operation.

[0017] Preferably the movable blade 34 is also provided with a second blade edge 46 also which permits the blade member 34 to be removed axially from the body 30, inverted and re-inserted to present a fresh blade edge 46 for co-operation with the static blade member 37. Again blade edges 46 may be sharpened by a surface grinding operation on the blade member 34. Although such an operation results in a reduction in the thickness of the blade member 34, the reduction in thickness is accommodated by adjustment of the bearing members 39.

[0018] A push rod (not shown) is attached to one end of the blade member 34 and serves to reciprocate the blade member 34 during operation of the linking machine.

[0019] A tubular portion 50 extends upwardly from the body portion 30. A suction tube 51 is secured to the tubular portion 50 and serves to remove the excess fabric which has been trimmed.

[0020] It has been found that the blade life of the trimming device of the present invention exceeds that of conventional trimming devices and also enables the blade members to be resharpened by a simple surface grinding operation. In addition since the blade members 34, 37 are maintained in surface contact by a non-resilient bearing member less wear and distortion of the blade members is experienced.

[0021] The second sewing station 22 includes a pair of needles 60,61 (shown schematically in Figure 6) which co-operate with one another in a conventional manner to form an oversew seam. Each needle is supplied with a separate yarn and during the stitch forming operation the stitch loop is formed about a stitch forming device 70 which is illustrated in Figures 6 and 7.

[0022] The stitch forming device 70 includes a static finger 71 which is mounted on a base 72. A resilient finger 73 is mounted on a support 74 and extends along side finger 71. The fingers 71 and 73 have the same profile which includes a lower recess 75 and an upper recess 76.

[0023] The finger portions 71 and 73 are spaced apart to define a gap through which the joined fabric edges to be oversewn are fed. The device 70 is arranged such that the upper edge 80 of the fabric edges to be oversewn is substantially level with the uppermost edge portion 79 of the fingers 71 and 73. Thus as seen in Figure 6 the upper edge 80 is located above the upper edge of each finger 71 and 73 as defined by recess 76.

[0024] The recesses 75 and 76 are located in the region of stitch formation by the needles 60,61. Thus recess 75 provides a region whereat a needle can penetrate the fabric between the points 15 and fingers 71 and 73 and thus the fabric in this region is fully supported by the fingers 71 and 73 during such penetration. Such support provides for a neater stitch formation.

[0025] Due to the presence of recess 76 the interconnection of stitch loops formed by the needles 60,61 is located, during the stitch formation directly upon the upper edge 80 of the fabric being oversewn.

[0026] With conventional stitch forming devices the location of the interconnection of the oversew stitch loops is sensitive to differences in tension between the two yarns fed to needles 60,61. Ideally, the interconnection of the oversew loops should be centrally located relative to the edge of the seamed fabric. It has been found that the present device renders the positioning of the interconnection of the oversew loops less sensitive to the differences in tensions of the two yarns and thus makes it easier to obtain a centrally located interconnection. In addition, the reduction in sensitivity to differences in tension has made it possible for different yarns to be used without requiring readjustment of the tensioners controlling supply of yarn to the needles 60,61.

Claims

1. A fabric trimming device comprising a movable blade member in slidable face to face contact with a fixed blade member, the movable blade member and fixed blade member having co-operating blade edges for cutting fabric located therebetween on reciprocation of said movable blade member relative to said fixed blade, non-­resilient bearing means for maintaining face to face contact between the movable and fixed blade members.

2. A device according to Claim 1 wherein the non-­resilient bearing means comprises at least one roller bearing which contacts the movable blade member.

3. A device according to Claim 1 or 2 wherein the static blade and movable blade are each surface ground to provide a blade edge.

4. A stitch forming device for use with an oversew needle, the device including a pair of fingers which are spaced apart to define a gap through which fabric to be oversewn can be fed, the fingers being arranged to extend along either side of the fabric and having an upper edge located between the edge of the fabric in the region of stitch formation of the oversew needle such that during formation of the stitch loop it lays directly on the upper side of the fabric to be oversewn.

5. A stitch forming device according to Claim 4 wherein one of the fingers is rigid and the other is resilient so that the fabric is resiliently gripped between the fingers as it is advanced along said gap.

6. A device according to Claim 4 or 5 wherein each finger has an upper and lower recess, the upper recess defining the upper edge of the finger in the region of stitch formation and the lower recess enabling a needle to penetrate beneath the fingers.

Drawing