Method for operating a sewing machine for forming a button or lacing hole

Abstract

When creating a buttonhole or lace-up hole in fabric (21) using a sewing machine, an initial cut (22) is first made in the fabric (21) by a cutting device of the sewing machine. The fabric (21) is then displaced relative to the cutting device along a displacement direction (y) by a displacement path (Δy) that lies between 0 mm and less than 1 mm. With the fabric (21) displaced, at least one further cut (23) is made. This results in the neatest possible buttonhole or lace-up hole.

Description

[0001] The invention relates to a method for operating a sewing machine for forming a buttonhole or eyelet in a sewing material. Furthermore, the invention relates to a sewing machine configured to implement the method and a software product for executing a program sequence according to such an operating method.

[0002] Buttonhole sewing machines are known in various forms, for example, from DE 10 2005 021 768 A1 and DE 10 2004 055 713 A1. A buttonhole is created either using a single cut or using several cuts offset from one another along a cutting direction to create the entire cutting length. DE 10 2009 004 605 A1 discloses a buttonhole machine. DE 100 85 290 B4 discloses a fabric cutting device for a sewing machine. KR 2007 0016971 A discloses a sewing machine with a controllable fabric cutting device in connection with sewing a keyhole buttonhole.

[0003] It is an object of the present invention to further develop an operating method of the type mentioned at the outset in such a way that the cleanest possible buttonhole or lace hole pattern results.

[0004] According to the invention, it was recognized that recutting an initially already performed fabric cut leads to a significant improvement in the cutting result, particularly with resilient fabrics where individual, incompletely cut residual fibers would otherwise remain. Between the initial cut and the at least one recut, the fabric is displaced by less than 1 mm relative to the cutting device. The displacement path is greater than 0 and can, for example, be in the range between 0.1 mm and 0.9 mm, between 0.2 mm and 0.8 mm, between 0.3 mm and 0.7 mm, and in particular in the range between 0.1 mm and 0.3 mm, or even in the range from 0.4 to 0.5 mm.By shifting the fabric relative to the cutting device in a range between 0 and less than 1 mm, a corresponding cutting offset of the cutting device relative to the fabric is achieved, which improves the quality of the cutting result, as identical cutting edge sections no longer interact with identical fabric sections during successive cuts. The small offset or displacement path between the initial cut and the subsequent cut also ensures that the shape of the resulting buttonhole or lace hole is not undesirably altered.

[0005] A buttonhole or lacehole seam can be sewn before or after the buttonhole or lacehole is formed in the fabric.

[0006] The method according to claim 2 is used when the general production of the buttonhole in particular requires several cuts that are significantly offset from one another along a cutting direction, which is also known in the prior art as multi-flex cutting. For each individual cut of such a multi-cut buttonhole production process, which then represents an initial cut, recutting can be performed after an offset of less than 1 mm. Alternatively, such recutting can only occur for certain predetermined individual cuts of such a multiple-cut process, in particular for the first and / or last cut.

[0007] According to claim 3, different offset paths can accommodate corresponding cut quality requirements, particularly in conjunction with a corresponding cut geometry. For example, a smaller offset path can be used in the eyelet area of an eyelet buttonhole than in the base cut area of the eyelet buttonhole.

[0008] Opposite displacement directions according to claim 4 can be adapted to the geometry of the buttonhole or lacehole to be created. In the case of a buttonhole, the offset at the end can be performed in such a way that no undesirable hole extension results.

[0009] This applies in particular to the method according to claim 5.

[0010] The advantages of a method according to claim 6 have already been explained.

[0011] The advantages of a sewing machine according to claim 7 correspond to those already explained above with reference to the method. The sewing machine can be a buttonhole machine, in particular an eyelet buttonhole machine. The sewing machine can be designed such that it can produce sewing material holes of various shapes, in particular a buttonhole and / or an eyelet buttonhole and / or a lace hole. The cutting device has a driven, movable cutting block and a knife that is stationary during the cutting process. Such a cutting device has proven itself in practice. During the cutting process, the cutting block is driven and thus moves relative to the stationary knife.

[0012] In principle, cutting devices known from the prior art can be used. Alternatively, both knives, or the knife and cutting block, could move relative to each other and relative to a machine frame during a cutting process. Alternatively, the cutting block can be stationary, and the knife interacting with it can be designed to be movable by a drive.

[0013] Using a software product according to claim 8, the operating method can be flexibly adapted to the requirements of a specific sewing machine. The software product can be retrofitted to an existing sewing machine. The software product can be made available on a storage medium. Alternatively or additionally, the software product can be made available for download.

[0014] Embodiments of the invention are explained in more detail below with reference to the drawings, in which: Fig. 1 shows a longitudinal view of an eyelet buttonhole sewing machine with a buttonhole cutting device; Fig. 2 shows, using the example of an eyelet buttonhole shown in plan view, a result of an initial cut generation of an operating method of the sewing machine for forming an eyelet buttonhole; Fig. 3 shows a Fig. 2 similar representation the result of a further (re-)cutting with the sewing material displaced along a displacement direction; Fig. 4 and 5 in relation to the Fig. 2 and 3 similar representation, the respective cutting results in a corresponding operating method for forming an eyeless buttonhole; Fig. 6 and 7 in relation to the Fig. 2 and 3 similar representation, the respective cutting results of the operating method for forming a lace hole in the sewing material; and Fig. 8 to 13 again in the Fig. 2 and 3similar representation of respective sequential cutting results of a further embodiment of the operating method of the sewing machine for forming an eyelet buttonhole, wherein an individual cutting length is significantly smaller than a total length of the eyelet buttonhole along the cutting direction.

[0015] How Fig. 1 can be seen, a buttonhole sewing machine is C-shaped, ie it has an upper arm 1, a lower, housing-like base plate 2 and an approximately vertical stand 3 connecting the two. An arm shaft 4 is mounted in the arm 1 in the usual way and can be driven by a drive motor (not shown). The arrangement of such a drive motor on such a sewing machine is known from DE 102 25 511 C1 and DE 102 25 512 C1. The drive of a vertically displaceable needle bar 5 with a needle 6 and an oscillating drive for this are derived from the arm shaft 4 in the usual way.

[0016] An xy-table 7 is arranged on the base plate 2. This table is a cross-slide movable in two horizontal coordinate directions, namely the x-direction and the y-direction. The xy-table 7 is designed in a conventional manner, as is known, for example, from DE 198 07 771 C1 (corresponding to US Pat. No. 6,095,066). The xy-table 7 is driven by drives (not shown), namely an x-drive and a y-drive, which are typically positionable electric motors, usually stepper motors, but also controllable DC motors. Such a design is known from DE 102 25 511 C1 and DE 102 25 512 C1. The xy table 7 represents a displacement device for displacing sewing material relative to stationary components of the sewing machine.

[0017] On the xy-table 7, a two-part support plate 8a, 8b is arranged, of which in the Fig. 1Only one partial support plate 8b is visible. Each partial support plate 8a or 8b is assigned a workpiece clamp 9a or 9b, which each has a partial support plate 10a or 10b mounted on the respective partial support plate 8a or 8b, each of which is assigned a clamping plate 11a or 11b. The clamping plates 11a or 11b are attached to double-armed bearing levers 12a or 12b. The components 9 to 12 are also shown in the Fig. 1 The subcomponents 9b to 12b are visible. Details of the structure and drive of the workpiece clamps 9a, 9b can be found in DE 102 16 808 C2 (corresponding to US 6,722,299 B2), to which reference is made in this regard.

[0018] Located behind the needle bar 5, viewed in the y-direction, is a buttonhole cutting device 13. It has a lower knife 14, which is arranged vertically in the base plate 2, i.e., in the z-direction, and a cutting block 15 arranged at the top. Associated with the cutting block 15 is a cutting drive 16, which is designed as a multi-stage, pneumatically actuated piston-cylinder drive and is illustrated and described in detail in DE 102 25 511 C1 and DE 102 25 512 C1. The stationary knife can also be arranged at the top, and the driven cutting block can also be arranged at the bottom.

[0019] As far as the sewing machine is shown and described up to this point, it is known from DE 10 2005 021 768 A and from DE 103 04 821 B3.

[0020] The sewing machine after Fig. 1further has a control / regulating device 17 which is in signal connection with the cutting device 13, the xy table 7 as a displacement device for displacing the sewing material relative to the cutting device 13 and in particular with the cutting drive 16 of the cutting device 13.

[0021] With the sewing machine Fig. 1 Different variants of an operating procedure for forming a buttonhole or lace hole in the sewing material can be carried out, which are described below using the Fig. 2 to 13 By changing knife / cutting block pairings and / or by a predetermined offset between the respective knife and the respective cutting block, different cutting patterns can be created with the help of the cutting device 13, for example an eyelet cut, a bead cut, or a looped hole cut, which are described in more detail below with reference to Fig. 2f.

[0022] Fig. 2 and 3show sequential cutting results for forming an eyelet buttonhole in the sewing material 21.

[0023] Fig. 2 shows the result of creating an initial eye cut 22, which runs along a cutting direction y, in the sewing material 21. The initial eye cut 22 is carried out by means of the cutting device 13 of the sewing machine 1.

[0024] The initial eyelet cut 22 is made within an eyelet buttonhole seam 22a of the eyelet buttonhole 20 that is sewn or to be sewn into the sewing material 21.

[0025] Following the creation of the initial cut 22, the material 21 is displaced to the cutting device 13 along a displacement direction that coincides with the cutting direction y, by a displacement path Δy. The displacement path Δy lies in the range between 0 mm and less than 1 mm and, in the embodiment according to Fig. 3 at about 0.5 mm. The direction of displacement during the displacement step to Fig. 3 is in the positive y-direction.

[0026] Fig. 3 shows the initial cut 22 in dashed lines and a further eye cut 23 in solid lines, which is cut displaced by the displacement path Δy along the cutting direction y due to the displacement of the sewing material 21 relative to the cutting device 13 in the positive y-direction in the sewing material 21 compared to the initial eye cut 23 in the negative y-direction. After performing the further eye cut 23, displaced by the displacement path Δy, in the process example according to the Fig. 2 and 3 the eyelet buttonhole 20 is completed. The two cuts 22, 23, which are made in the sewing material 21 in the cutting direction y displaced by the displacement path Δy, lead to an improvement in the cutting pattern of the eyelet buttonhole 20 without undesired incompletely severed fiber remnants.

[0027] The eyelet buttonhole seam 22a can be sewn before or after the cuts 22, 23 are created in the sewing material 21.

[0028] Fig. 4 and 5 show cutting results according to the Fig. 2 and 3 when forming an eyeless buttonhole 24 with buttonhole seam 24a.

[0029] Fig. 4 shows the result of the generation of an initial caterpillar cut 25 with cutting direction y.

[0030] Fig. 5 shows the result of creating another bead cut 26 after displacing the fabric 21 in the positive y-direction, i.e., along the displacement direction, by the displacement path Δy, again in the range of 0.5 mm. The two bead cuts 25, 26 extend exactly one upon the other, except for their respective end areas, where there is an overhang by the displacement path Δy.

[0031] Figs. 6 and 7 show the conditions for forming a lacing hole 27. The lacing hole is formed by round lacing hole cuts. The lacing hole 27 has a correspondingly round lacing hole seam 28.

[0032] Fig. 6shows the result of creating an initial lace-hole cut 29.

[0033] Fig. 7 shows the result of the creation of a further eyelet cut 30 after a displacement of the sewing material 21 along the displacement direction in the positive y-direction by the displacement path Δy, for example in the range of 0.3 mm.

[0034] The displacement path Δy is so small that a geometry of the generated eyelet 27 is not affected by the displacement path Δy.

[0035] In the illustrated embodiment according to the Figs. 6 and 7 The initial eyelet cut 29 is concentric with the also round eyelet seam 28. In comparison, the further eyelet cut 30 is eccentric by the displacement path Δy. Alternatively, both eyelet cuts 29, 30 can be eccentric to the center of the eyelet seam 28, one in a positive direction and one in a negative direction.

[0036] Based on the Fig. 8 to 13A further variant of an operating method of the sewing machine for forming an eyelet buttonhole is described below. Components and functions described above with reference to the Fig. 1 to 7 and in particular with reference to the Fig. 2 and 3 already explained, have the same reference numbers and will not be discussed in detail again.

[0037] In the procedure according to the Fig. 8 to 13 an eyelet buttonhole 31 is produced by means of several individual cuts, the individual cut length of which along the cutting direction y is each significantly shorter than a total length of the eyelet buttonhole 31 along the cutting direction y.

[0038] Fig. 8 shows the result of the creation of an initial eye cut 32, which, apart from the fact that a base adjoining the cut eye is significantly shorter in the initial eye cut 32 than in the initial eye cut 22.

[0039] Fig. 9 shows according to the Fig. 3 the result of a further eye cut 33 after the material 21 has been displaced along the displacement direction (positive y-direction) by the displacement path Δy, again in the range between 0 mm and less than 1 mm, for example, in the range of 0.5 mm. The eye cut 33 is therefore a follow-up cut of the eye cut 32.

[0040] Fig. 10 to 12 show further cutting steps for creating further sections of the cut base of the eyelet buttonhole 31. Here, further caterpillar cuts are made, each in the negative y-direction with offset paths that are at least 1 mm and can, for example, be larger than 2 mm, 3 mm or even 5 mm.

[0041] Result of the cut after Fig. 10 is a caterpillar cut 34, which can overlap with a base section of the eye cuts 32 or 33. Result of the further cuts according to the Fig. 11 and 12are further caterpillar cuts 35, 36, which in turn overlap in pairs along the cut base of the eyelet buttonhole 31, whereby between the caterpillar cuts 34 to 36 there are offset paths which are greater than the displacement path Δy.

[0042] After the bead cut 36, the material is again shifted in preparation for a recut, this time by a displacement distance Δy in the negative y-direction. A subsequent bead cut 37, the result of which is Fig. 13 is shown, is then compared to the caterpillar cut 36 after Fig. 12 in the positive y-direction by the displacement distance Δy. This displacement distance Δy between the bead cuts 36 and 37 is in the range between 0 mm and less than 1 mm, for example, in the range of 0.5 mm. Thus, the bead cut 37 is a follow-up cut of the bead cut 36.

[0043] In the manufacturing process according to the Fig. 8 to 13the steps "displaced by the displacement path Δy" and "creating a subsequent, further cut" are therefore carried out repeatedly, in the Fig. 8 to 13 shown example between the cuts according to the Figs. 8 and 9 and between the cuts after the Figs. 12 and 13 , i.e. at the beginning and end of the eyelet cut of the eyelet buttonhole 31.

[0044] In other variants of the operating procedure, after each of the initial cuts, which in the multi-cut procedure are carried out after the Fig. 8 to 13 are shown, not only according to the sections Fig. 8 and Fig. 12 , but also after the cuts after the Figs. 10 and 11 , further recuts after a displacement by a displacement path Δy in the range between 0 mm and less than 1 mm.

[0045] The operating procedure according to the Fig. 8 to 13ensures that when creating a buttonhole with multiple cuts, an undesirably unclean cutting pattern is avoided, particularly in the area of the first and last cut of such a multiple cutting process for forming the buttonhole.

[0046] Using the multiple cut method, which was explained above using an eyelet buttonhole as an example, an eyeless buttonhole can also be cut.

[0047] If, during the formation of the buttonhole or lace-up hole, several cutting sequences are formed from an initial cut and, after a displacement by a displacement path Δy in the range between 0 mm and less than 1 mm, have a further subsequent cut, a preceding displacement step by different displacement paths can be carried out before the creation of the respective further subsequent cut. In the embodiments according to the Fig. 8 to 13For example, the relocation step between the cuts can be Figs. 8 and 9 on the one hand and the displacement step between the cuts according to the Figs. 12 and 13 On the other hand, it can be a completely different displacement path, for example between the cuts after the Figs. 8 and 9 by 0.3 mm and between the cuts according to the Figs. 12 and 13 by 0.8 mm. If several displacement steps by the displacement path Δy in the range between 0 mm and less than 1 mm occur between a respective initial and a subsequent re-cut, these displacement steps can be carried out along mutually opposite displacement directions.

[0048] In the operating method for forming the buttonhole or lace hole, at least two consecutive cuts can also be made without intermediate displacement by a finite displacement path.

[0049] The variants of the operating method described above can be present as a programmed operating sequence program for the sewing machine. A corresponding program sequence can be designed as a software product executable by the control / regulation device 17. The software product can be stored on a storage medium or made available for download. The software product can be used to retrofit existing machines.

Claims

1. Method for operating a sewing machine for forming a button or lacing hole in sewing material (21) having the following steps: - creating an initial cut (22; 25; 29; 32; 36) in the sewing material (21) with a cutting device (13) of the sewing machine, - displacing the sewing material (21) relative to the cutting device (13) along a displacement direction (y) by a displacement path (Δy), which is greater than 0 mm and less than 1 mm, - creating at least another cut (23; 26; 30; 33; 37) with the sewing material (21) displaced.

2. Method according to claim 1, characterised in that the steps of "displacing" and "creating another cut" are repeated.

3. Method according to claim 2, characterised in that prior to the respective other cut (23; 26; 30; 33; 37) being created, the respective upstream displacement steps are carried out with displacement paths (Δy) that are different from one another.

4. Method according to claim 2 or 3, characterised in that prior to the respective other cut (23; 26; 30; 33; 37) being created, the respective upstream displacement steps are carried out along mutually opposite displacement directions (-y, +y).

5. Method according to claim 4, characterised in that a first and a last displacement step are carried out along mutually opposite displacement directions (-y, +y).

6. Method according to one of claims 2 to 5, characterised by at least two successive cuts without intermediate displacement by a finite displacement path.

7. Sewing machine, designed to carry out a method according to one of claims 1 to 6 - having stitch formation tools (6), - having a cutting device (13) for creating cuts (22, 23; 25, 26; 29, 30; 32, 33, 34, 35, 36, 37) in the sewing material (21), - having a displacement device (7) for displacing the sewing material (21) relative to the cutting device (13), - having a control / regulation device (17), which is in signal communication with the cutting device (13) and the displacement device (7), - wherein the cutting device (13) has a driven displaceable cutting block (15) and a blade (14) that is stationary during the cutting procedure, - wherein the control / regulation device (17) is designed in such a way that the sewing material (21) is displaced, between the creation of the initial and the at least one other cut, relative to the cutting device (13) along the displacement direction (y) by the displacement path (Δy), which is greater than 0 mm and less than 1 mm.

8. Software product for executing a program sequence corresponding to a method according to one of claims 1 to 6, wherein the software product is intended to carry out the method by controlling the control / regulation device of the sewing machine according to claim 7.

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