GB1559434A - Workpiece support for sewing machines - Google Patents

Description

(54) WORKPIECE SUPPORT FOR SEWING MACHINES (71) We, KOCHS ADLER AKTIENGESELLSCHAFT, of 2, Teichstrasse, 4800 Bielefeld 1, Federal Republic of Germany, a Company organised under the laws of the Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the followng statement: The invention relates to a workpiece support utilisable for sewing machines.

The aim of the invention is to secure the workpieces, which are to be introduced into a template controlled sewing machine, on a workpiece support of the sewing machine as close as possible to the path of the seam during its production, and to simplify the conversion of the sewing machine to workpieces of different dimensions and/or to a different seam path.

The use of exchangeable workpiece clamp holders, consisting of clamp plates hinged together, in sewing machines for the purpose of producing seams on workpieces of determined shape and/or size is generally known.

It is also known to provide automatic sewing machines with ajustable workpiece holding devices. Although these permit adjustment to workpieces of different sizes, they cannot be used for workpieces of different shapes.

Finally a workpiece holding and clamping device is also knwon which has a plurality of workpiece clamp holders clamping the workpiece substantially in its edge zones.

Each of these relatively narrow workpiece clamp holders has a workpiece support bar and a workpiece clamp plate which is articulated to one arm of a two-armed lever.

The latter is mounted in a support carried by the workpiece support bar for rotation against the tension of a spring. These workpiece clamp holders are mounted in the sewing machine so as to be individually movable and clampable, in order to enable them to be arranged to receive workpieces of different sizes and shapes.

It is true that the individual workpiece clamp holders can be aligned relatively simply, but this operation takes up a great deal of time, particularly when a change of shape occurs frequently. This known device is mainly suitable for narrow workpieces, since the space required for large workpieces to pass between the upper workpiece support bars and the workpiece clamp plates is limite.

The invention seeks to provide, particularly in an automatic sewing machine, means enabling both smaller and larger workpiece parts to be recieved on the workpiece support and to be held reliably and without creasing near the seam which is to be sewn, and also to permit rapid change-over to workpieces having different seam paths.

According to the invention there is provided a workpiece support for a sewing machine, comprising a multiplicity of support segments which are disposed side by side and are displaceable in relation to one another, and which in their edge zones adjacent the edge of the workpiece which is to be machined are provided with needles, the workpiece support including a device which is adapted to be lowered onto the workpiece to secure the workpiece on the needles and is withdrawn prior to sewing of the workpiece.

For the displacement of the support segments a contour adjuster equipped with templates is provided. Each template has a contour which corresponds to the path of the seam which is to be formed on the workpiece. The support segments can be formed from bars of U-shaped crosssection, whose webs carrying the workpiece are provided with cutouts for the passage of the needles. The needles securing the workpiece are disposed on one arm of a twoarmed lever, which is mounted for rotation in each of the support segments, and are held by means of a spring in a position passing through the support segments inside the cutout.

A multiplicity of support segments, which are provided with stops for the edge of the workpiece, are distributed over the length of the workpiece support. These stops are connected to the two-armed levers by means of a lever arrangement so as to be pivotable in such a manner that on the lowering of the needles below the surface of the support segments the stops are swivelled upwards.

The securing device mentioned above consists of a bristle brush which extends over the entire length of the workpiece support and which is adapted to be lowered onto the workpiece when the needles are in a position below the surface of the support segments.

The support segments, the two-armed levers for the needles, and the lever arrangement for the stops are disposed on carrier frames which are received in straight guides and under the action of springs are pressed against the contour adjuster template which is operative at the moment in question. The carrier frames can be provided with projecting arms for the arrangement of band carriers receiving a guide template which is in band form, adapted to guide a driven roller, and determines the path of the seam.

One embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 shows the workpiece support of the invention in partial elevation in perspective, Figure 2 is a section corresponding substantially to the line II-II in Figure 1, Figure 3 is a partial section corresponding generally to Figure 2 but with the stops in a different position, and Figures 4 to 6 are sections corresponding to Figure 3, the swivellable stops and needles being shown in different working positions.

On a base plate 1 (Figures 1 and 2), which is part of a frame (not further shown) of the sewing machine, is mounted a carrier 2 which is provided with two bars 5 and 6 provided with transverse guide grooves 3,4.

The guide grooves 3,4 serve for the straight guidance of carrier frames 7,8, which are disposed side by side and of which a multiplicity are provided. Each frame is compose of a bottom bar 9 having a fillet 10 (Figure 2), an upper bar 11, two spacers 12 and 13 disposed between the two bars 9 and 11, two screws 14 joining together the parts mentioned, and mounting parts 16 and 17 respectively (Figure 1) fastened by means of screws 15 to the bars 9 and 11. The carrier bars 9 and 11 are provided at their outer ends with the mounting parts 16 and 17, each part 17 having a recess 18 at its upper end. In this recess a two-armed lever 19 is pivotally mounted about a pin 20, one arm 19'of this lever having inserted in it a needle 21 the tip of which points upwards. The other arm 19"of the two-armed lever 19 is acted on by the tension of a spring 22, which presses the end of the arm 19"into a guide groove 23 in a lifting plate 24, in which it is slidable. On the mounting parts 16 of the carrier frames 8 are fastened two side plates 25, between which a two-armed lever 27 is pivotally mounted on a pin 26 (Figures 1 to 6). One arm 27'of this lever 27 also carries a needle 21 whose tip is directed upwards, while its other arm 27"is acted on by the tension of a spring 28 and is guided in a guide groove 23 and pressed against the lifting plate 24. Between the two side plates 25 is also disposed a two-armed lever 29 which is mounted for rotation about a pin 30 and the arm 29'of which is connected by means of a lever 31 to the arm 27"of the two-armed lever 27, its other arm 29"being connected by means of another lever 32 to pivot arm 33 which is mounted at one end on the arm 27'of the two-armed lever 27 for rotation about a pin 34. On the free end of the pivot arm 33 is mounted a stop 35 for the workpiece 36.

For the supporting of the workpieces all the supporting frames 7,8 are provided with support segments 37, which consist of rela tively narrow U-shaped bars and are fastened by means of screws 38 and pins 20,26 on the mounting parts 17 and on the side plates 25 respectively. At their outer ends the support segments 37 are provided with bores 39 for the passage of the needles 21.

Projecting arms 40 (Figures 1 and 2) are mounted asjustably on the mounting parts 16,17 by means of screws 41 passing through slots 42 in the arms 40. The arms 40 serve to receive band carriers 43 in which a resilient band 43'determining the shape of the seam contour is mounted as a guide template for a driven roller 44 in line with the sewing needle 45 of the sewing machine 46.

The carrier frames 7 and 8 mounted in the guide slots 23 are aligned on a carrier 47 disposed in the frame (not further shown) of the sewing machine, and are slidable with slight clearance between the carrier 47 and the bars 9 and 11. All the carrier frames 7,8 are pressed against the front edge of the template 52 by means of tension springs 48, each of which is supported at one end on a plate 49 mounted in a fixed position in the frame and at the other end on a supporting plate 50, the template 82 corresponding to the contour 51 of the workpiece 36 and which forms part of a contour adjuster 53.

The contour adjuster 53 consists of a template carrier 54, which is mounted in a frame for intermittent rotation and is provided either with a number of templates 52 to 52lv each consisting of a single piece and designed for certain fixed workpice contours or, entirely or partially, of ajustable templates 55 each of which is adaptable to the contour of the workpiece. The template 55 has a plate 57 which is provided with slots 56 and which is fastened on the template carrier 54. Bar-shaped intermediate members 58 are slidably bolted to the plate 57 in the slots 56 in the latter, and the template elements 59 forming a template are mounted on the intermediate members 58 by which they are supporte by the plate 57.

For the purpose of displacement or adjustment these template elements 59 are provided with slots 60 and their front edges 61 form a stop for the spacers 13 of the carrier frames 7,8.

A bristle brush 62 adapted to be lowered onto all the support segments 37 is provided in the frame. A control system (not shown) is provided for the lifting movements of the bristle brush 62 and the lifting plate 24.

The operation of a sewing machine provided with the workpiece support according to the invention can be described as follows: In the starting positions shown in Figures 1 and 3 the needles 21 provided on the two-armed levers 19,27 have been pivoted below the surface of the support segments 37 because of the raising of the lifting plate 24. Simultaneously therewith the swivel arms 33, which are adapted to be operated by the lever arrangement 29 to 32, have been swivelled upwards in the carrier frames 8 distributed over the length of the workpiece support, so that the stops 35 provided on them can serve to locate the workpiece to be inserted.

After the insertion of the workpiece 36 on the support segments 37 the bristle brush 62 is lowered onto the workpiece 36 by means of the control system (not shown), as can be seen in Figure 4. Through the lowering of the lifting plate 24 (Figure 5) the two-armed levers 19 and 27 are thereupon swivelled through the action of the springs 22 and 28 respectively in such a manner that the needles 21 pass upwards through the bores 39 provided in the support segments 37 and through the workpiece 36 into the bristle brush 62 holding down the workpiece 36.

Because of the operation of the twoarmed levers 19 and 27 the swivel arms 33 articulated on the levers 27 together with the stops 35 have also been swung downwards (Figure 5), so that after the raising of the bristle brush 62 these stops 35 pass out of the path of movement of the sewing machine 46 which is then brought into operation and which by means of the driven roller 44 is guided along the template 43'in band form and thus also along the workpiece 36.

Due to the fact that the workpiece 36 is penetrated by the needles 21 only after the bristle brush 62 has been lowered onto the workpiece 36, it is ensured that no creases can be formed between the needles 21 and that because of the multiplicity of needles the workpiece is reliably secured without additional clamps.

Through the rotation of the template carrier 54 the templates 52 to 52lu, which serve to locate the carrier frames 7 and 8 and are made for predetermined contours, or the contour which is composed of individual elements 55 and is thus adjustable can be brought into the working position.

Claims (9)

WHAT WE CLAIM IS:

1. A workpiece support for a sewing machine, comprising a multiplicity of support segments which are disposed side by side and are displaceable in relation to one another, and which in their edge zones adjacent the edge of a workpiece which is to be machined are provided with needles, the workpiece support including a device which is adapted to be lowered onto the workpiece to secure the workpiece on the needles, and is withdrawn from the needles prior to sewing of the workpiece.

2. A workpiece support as claimed in claim 1, wherein a contour adjustment is provided for the displacement of the support segments which is equipped with at least one template, the or each template having a contour which corresponds to the path of the seam which is to be formed on the workpiece.

3. A workpiece support as claimed in claim 1 or claim 2, wherein the support segments are formed from bars of U-shaped cross-section, whose webs supporting the workpiece are provided with apertures for the passage of the needles.

4. A workpiece support as claimed in claim 3, wherein each needle is disposed on one arm of a two-armed lever which is mounted for rotation in each of the support segments and is held by means of a spring in a position passing through the aperture in the support segment.

5. A workpiece support as claimed in claim 4, wherein a number of support segments which are provided with stops for the edge of the workpiece, are distributed over the length of the workpiece support, and the stops are connected to the twoarmed levers by means of a lever arrangement so as to be pivotable in a direction such that on the lowering of the needles below the surface of the support segments the stops are pivoted upwards.

6. A workpiece support as claimed in any one of claims 1 to 5, wherein the securing device consists of a bristle brush which extends over the entire length of the workpiece support and which is adapted to be lowered onto the workpiece when the needles are in a position below the surface of the support segments.

7. workpiece support as claimed in claim 5 when dependent on claim 2, wherein the support segments, the two-armed levers for the needles and the lever arrangement for the stops are disposed on carrier frames which are received in straight guides and are pressed under the action of springs against the selected template of the contour adjuster.

8. A workpiece support as claimed in claim 7, wherein the carrier frames are provided with projecting arms for the support band carriers receiving a guide template which is in band form, adapted to guide a driven guide roller and which thereby determines the path of the seam.

9. A workpiece support for a sewing machine, substantially as hereinbefore described and with reference to the accompanying drawings.