Sewing unit

Abstract

The invention relates to a sewing unit (1) comprising a CNC controller (2) and a sewing machine (3). Said sewing machine has a sewing-material support plate (6), a sewing upper part (4) and a sewing lower part (5). Said sewing lower part has a controlledly rotationally drivable looper having an under-thread supply in a looper case. The looper is rotatable about an axis which extends in parallel with the sewing-material support. The looper has a diameter of at least 30 mm. A case holding component arranged in the region of the sewing-material support is in engagement with the looper case such that it does not rotate the looper case at the same time when the looper is rotated. The sewing lower part has a controlledly rotationally drivable case ventilating means for displacing the looper case between a neutral position and a ventilated position in which a space for a thread between the looper case and the case holding component is enlarged in comparison with the neutral position. The result is a sewing unit in which mass production is ensured with high overall unit effectiveness even when thick threads are used.

Description

[0001] sewing machine

[0002] This patent application claims priority from German patent application DE 10 2022 206 102.0, the contents of which are incorporated herein by reference.

[0003] The invention relates to a sewing system.

[0004] Such sewing systems are known on the market for producing seams, for example, in the automotive industry and in the field of technical textiles. EP 2 050 853 A1 discloses a sewing machine and a looper system for a sewing machine. DE 10 2018 205 835 A1 discloses a sewing machine. DE 41 28 336 CI discloses a sewing machine for stationary, large-area sewing material. DE 2 247 050 A discloses a thread take-up device for sewing machines, preferably for multi-needle lockstitch machines.

[0005] It is an object of the present invention to further develop a sewing system in such a way that mass production is ensured even when using thick threads with high overall system effectiveness.

[0006] This object is achieved according to the invention by a sewing system having the features specified in claim 1.

[0007] According to the invention, it was recognized that it is possible to modify a bobbin case opener, known in principle, for example, from DE 100 25 851 CI and DE 32 44 946 CI, so that it can also interact with a very large hook with a correspondingly large bobbin thread supply. An example of a large hook is known from DE 20 2013 005 112 U1. The increased clearance for the thread between the hook bobbin case and the bobbin case holding component, created by the bobbin case opener, reduces thread friction during sewing in the hook-side material support area. This reduced thread friction also enables the use of thicker threads with a size of NM 20 or smaller. Such thick upper or lower threads can then be sewn at a sewing speed of more than 2000 stitches per minute, for example with 2000 stitches per minute, with 2200 stitches per minute, with 2500 stitches per minute or even with 2800 stitches per minute.

[0008] The sewing machine's lower section can be designed to accommodate a semi-automatic or fully automatic bobbin changing system for automated replacement of the bobbin thread supply. This further increases the overall efficiency of the sewing machine.

[0009] The sewing system enables the production of seams for the automotive industry, for example dashboard, vehicle seat, belt or airbag seams.

[0010] A C-frame or another frame geometry can be used to hold the sewing head and the sewing head of the sewing machine.

[0011] The needle bar can be moved up and down along a z-coordinate of a sewing machine coordinate system. In this case, the upper sewing section and the lower sewing section can be designed to be displaceable along the x- and / or y-coordinates via appropriately controlled drives. The sewing machine can therefore be designed with a movable sewing machine and / or with a movable sewing machine support plate.

[0012] The sewing machine can be equipped with a monitoring system for the remaining thread quantity of the upper thread and / or the lower thread. The sewing machine can be equipped with at least one vibration sensor for monitoring maintenance requirements, particularly for bearings of the sewing unit, in particular the upper sewing section and / or the lower sewing section. The upper sewing section can be equipped with a needle cooling system.

[0013] A thread cutting device according to claim 2 results in a clean seam appearance. A thread cutting device of the type known from EP 2 300 654 B1 can be used. The excess length achieved with the thread cutting device can be 15 mm, but can also be smaller, for example 12 mm or 10 mm. A starting thread and / or an end thread of the formed seam can be cut off. A thread finger can interact with the thread cutting device during thread cutting. A corresponding process sequence can include, after a sewing stop, grasping the thread to be cut with the thread finger for thread pulling and subsequently cutting the thread grasped by the thread cutting device after thread pulling.

[0014] A design of the thread cutting device according to claim 3 has proven effective for producing the shortest possible overhang within a reproducible process sequence. The cutting blade can be guided over a cam or guide. A narrow housing head design of the sewing head according to claim 4 allows several sewing machines to work side by side in parallel within the sewing system to process a large sewing area. The width of the housing head of the sewing head can be 280 mm, 250 mm, or even smaller. This width is usually at least 200 mm.

[0015] Mounting the upper thread supply according to claim 5 allows for a particularly narrow width of the sewing head in the operating configuration. The upper thread supply can then be designed flush with the housing arm section.

[0016] A thread tensioning device according to claim 6 enables good seam pattern control. The thread tension can be adjusted differently for individual seam sections of a seam to be produced.

[0017] A presser foot according to claim 7 allows the sewing process to be adapted to different fabric conditions. The presser foot adjustment can be individually configured for individual seam sections of a seam to be produced, thus meeting the corresponding section-specific requirements.

[0018] Embodiments of the invention are explained in more detail below with reference to the drawings, in which:

[0019] Fig. 1 shows a schematic side view of the main components of a CNC-controlled sewing system with a sewing machine, comprising a sewing upper part and a cooperating sewing lower part; Fig. 2 shows a perspective view of a sewing upper part for use in the sewing system according to Fig. 1;

[0020] Fig. 3 shows a perspective view of a sewing lower part for use in the sewing system according to Fig. 1;

[0021] Fig. 4 in a front view details of the sewing lower part including a controlled drivable capsule lifter;

[0022] Fig. 5 in a view of the sewing lower part obliquely from above, a gripper capsule of a gripper relative to a capsule holding component in a neutral position;

[0023] Fig. 6, in a view similar to Fig. 5, shows the gripper capsule in a position which is lifted compared to the neutral position due to the action of a capsule lifter, which is also referred to as the open position; and

[0024] Fig. 7 in a side view an embodiment of the sewing upper part with a thread finger for pulling back an upper thread after sewing a seam and before cutting the thread.

[0025] A sewing system 1 has a CNC control 2, shown schematically in Fig. 1, and a sewing machine 3. The sewing machine 3 has a sewing upper part 4 and a sewing lower part 5.

[0026] The sewing unit 1 further has a sewing support plate 6, which provides a sewing material support in a sewing material support plane 7. The sewing upper part 4 and the sewing lower part 5 of the sewing machine 3 are mounted on a frame 8 of the sewing machine 3 of the sewing unit 1.

[0027] To facilitate the description of spatial relationships, a Cartesian xyz coordinate system is used below. In Figure 1, the x-axis runs perpendicular to the plane of the drawing. The y-axis runs horizontally to the right in Figure 1. The z-axis runs vertically upward in Figure 1.

[0028] The frame 8 is roughly C-shaped so that a usable sewing area in the xy plane, particularly along the y direction, can have a large extension, which can be greater than 1000 mm x 1000 mm.

[0029] During sewing, the workpiece support plate 6 is displaced relative to the upper sewing part 4 on the one hand and to the lower sewing part 5 on the other hand along the x-direction and / or along the y-direction. Depending on the design of the sewing system 1, this relative displacement can be such that the frame 8 of the sewing machine 3 moves relative to the workpiece support plate 6, thus the workpiece support plate 6 is fixed, or that the workpiece support plate 6 moves toward the then stationary frame 8. In a further variant, both the frame 8 and the workpiece support plate 6 can move relative to one another along the x-direction and / or along the y-direction.

[0030] Fig. 2 shows details of the sewing head 4. The sewing head 4 has a needle bar 9 that can be moved up and down in a controlled manner along the z-direction. Depending on the design of the sewing head 4, the needle bar 9 can be cooled to guide a sewing needle held there, not shown in Fig. 2. The sewing head 4 has an upper thread guide for guiding an upper thread from an upper thread supply 10 in the form of a thread spool to the needle bar 9. The upper thread is guided along this upper thread guide in Fig.

[0031] 2 not shown. This upper thread guide includes a thread clamp 11, which is controlled by a clamp drive 12, which may be pneumatic, and which is arranged near the needle bar 9.

[0032] A thread break sensor 13, which can be designed as an optical sensor, can be arranged in the area of ​​the thread clamp 11. Such a thread break sensor 13 can monitor whether upper thread is still being fed to the needle bar 9.

[0033] The upper thread guide also includes a thread lever 14 and a thread tension regulator 15, which can be used to set the thread tension of the upper thread. Depending on the design of the sewing head 4, a thread tension sensor 16 can be arranged in the area of ​​the thread lever 14, which can be used to monitor the thread tension of the upper thread.

[0034] The movement of the needle bar 9 and the thread take-up lever 14 is controlled by a sewing drive motor 17. A position of the sewing tools of the sewing machine 3 can be manually moved via a handwheel 18 of the sewing head 4. A rotational axis of the handwheel 18 runs parallel to the x-direction, i.e., perpendicular to a C-plane (yz-plane) of the frame 8 and also perpendicular to the extension of an arm shaft (extension along the y-direction) of the sewing head 4, from whose rotational movement the drive of the needle bar 9 and the thread take-up lever 14 is derived. The sewing head 4 can additionally be equipped with a presser foot, which is not shown in Fig. 2. Such a presser foot is held on a presser foot bar 19. An adjustment drive 20, which is designed as a servo motor or as a pneumatic drive, is used to adjust the height of the presser foot bar 19 along the z-direction.

[0035] A pneumatic fan drive 21 can be provided to provide suspension for the presser foot bar 19.

[0036] A further monitoring sensor 22 of the sewing head 4 monitors a “top dead center” position of the needle bar 9. The monitoring sensor 22 can therefore be designed as an optical sensor.

[0037] To monitor the bearing condition of the sewing head 4, the sewing head can have a vibration sensor 23. As soon as vibrations of the sewing head 4 detected by the vibration sensor 23 exceed a tolerance value, a signal can be output to prepare for maintenance of the sewing machine 3.

[0038] To monitor a lubricant fill level, in particular an oil fill level, for lubricating moving parts of the sewing upper part 4, the sewing upper part 4 has a fill level sensor 24.

[0039] A top thread level sensor 25, which may be an optical sensor, is used to monitor the fill level of the top thread supply 10. The top thread supply 10 is mounted on a housing head 26 of the sewing head 4. This mounting position of the top thread supply 10 is in an extension of a housing arm section 27 of the sewing head 4, which extends along the y-direction and ends in the housing head 26.

[0040] The needle bar 9 and the presser foot bar 19 are guided in the housing head 26.

[0041] Depending on the design of the sewing head 4, the housing head 26 in an operating version including the upper thread supply 10 can have a width in the x-dimension, i.e. parallel to the sewing material support plane 7 and perpendicular to the extension dimension y of the housing arm section 27, which is at most 300 mm and which can be, for example, 280 mm or 250 mm.

[0042] Alternatively, the upper thread supply 10 can also be mounted on the frame 8 or arranged next to the housing head 26, as shown in Figs. 1 and 7.

[0043] The sewing system 1 also includes a reading device 28, schematically shown in Fig. 2, for an upper thread type provided with the upper thread supply 10. The reading device 28 can be a barcode reader.

[0044] Fig. 3 shows an embodiment of the sewing lower part 5 of the sewing machine 3 of the sewing unit 1. The sewing lower part 5 interacts with the sewing upper part 4 to form a seam. For this purpose, the sewing lower part 5 has a controlled, rotationally drivable hook 30 with a bobbin thread supply in a hook spool 31, which is housed in a hook case 32. The hook 30 has a hook point that interacts with the sewing needle attached to the needle bar 9 of the sewing upper part 4 to form the stitch or seam. In this way, a lockstitch, in particular a double lockstitch, can be produced.

[0045] Including the hook tip, the hook 30 is rotatable about a rotation axis 33 running parallel to the y-axis. This rotation axis 33 runs parallel to the workpiece support 7, i.e., parallel to the xy-plane.

[0046] The receptacle in the hook capsule 32 for the hook spool 31 with the bobbin thread supply has an outer diameter, measured perpendicular to the rotation axis 33, which is greater than 30 mm.

[0047] In the area of ​​the material support plate 6, a holding web 34 (see Figs. 5 and 6) is arranged as a capsule holding component, which is firmly connected to a frame 35 of the sewing lower part 5. The holding web 34 engages with a holding recess 36 of the hook capsule 32 such that the hook capsule 32 does not rotate when the hook 30 rotates about the rotation axis 33. In the circumferential direction about the rotation axis 33, the holding recess 36 is larger than the holding web 34, so that in this circumferential direction, depending on the circumferential position of the holding recess 36 relative to the holding web 34, gaps, i.e., a free space, are present.

[0048] The sewing lower part 5 has a controlled, drivable capsule lifter 37 (see Fig. 4) for displacing the hook capsule 32 in the circumferential direction about the rotation axis 33 between a neutral position, which is shown in Fig. 5, and a lifted position, which is shown in Fig. 6. A lever tip of the capsule lifter 37 cooperates with a counter surface of the hook capsule 32 to displace the hook capsule 32 in the circumferential direction.

[0049] The rotary drive of the hook 30 and also the drive of the capsule lifter 37 is derived from a sewing drive 38 of the sewing lower part 5.

[0050] A stitch length during seam formation can be in the range between 2 mm and 10 mm.

[0051] The sewing lower part 5 in turn has a bobbin thread fill level sensor 39, a monitoring sensor 40 for monitoring an initialization position of a hook tip of the hook 30, a vibration sensor 41 for monitoring a bearing condition of bearings of the sewing lower part 5 and a lubricant fill level sensor 42, which correspond in their structure and mode of operation to the sensors already explained above with reference to the sewing upper part 4.

[0052] In the released position of the gripper capsule 32 according to Fig. 6, compared to the position according to Fig. 5, it is displaced by a few angular degrees in the circumferential direction around the axis of rotation 33 in Figs. 4 to 6 counterclockwise relative to the holding web 34. On the left side of the holding web 34 in Fig. 6, in the lifted position, there is then an increased free space between the holding web 34 and the holding recess 36 of the hook capsule 32 compared to the neutral position for the passage of a bobbin thread 43 between the hook capsule 32 and the support-side components, in particular the holding web 34. This increased free space in the lifted position according to Fig. 6 reduces thread friction during sewing operation of the sewing machine 3. Even thick threads 43 with a weight of at least 50 g per 1000 m of thread (50 tex = 20 NM) can be sewn with an operating speed of the sewing machine 3 of at least 2000 stitches per minute.The operating speed can be 2200, 2400, or even 2500 stitches per minute, for example, and can even be higher. The thread can also be thicker or heavier than 50 tex, for example, 77 tex (= 13 NM).

[0053] The upper thread and / or the bobbin thread can be a polyamide thread and / or a nylon thread. The upper thread and the bobbin thread can be different colors.

[0054] The hook 30 is mounted on the frame 35 of the sewing lower part 5 in such a way that an automatic changing system for changing the hook spool 31, i.e. the bobbin thread supply, is possible.

[0055] Sewing system 1 can be used to produce seams for the automotive industry, for example dashboard, vehicle seat, belt or airbag seams.

[0056] The sewing lower part 5 also has a thread cutting device 44, components of which are shown in Figs. 5 and 6. The thread cutting device 44 serves to cut off thread ends of the upper thread or the lower thread that protrude beyond a seam formed by the sewing machine 3. After cutting by the thread cutting device 44, cut thread ends remain with a maximum protrusion length beyond the formed seam of 15 mm. This protrusion length can also be smaller, for example, 12 mm or 10 mm. The thread ends can be a starting thread or an end thread of the seam.

[0057] The thread cutting device 44 has a cutting blade 45, the thread catching hook and cutting edge of which are covered by a counter blade 46 of the thread cutting device 44 in Fig. 5 and 6. The cutting blade 45 is shown in a cutting position in Fig. 5 and in a neutral position in Fig. 6. To cut the thread, the cutting blade 45 is pivoted about a pivot axis running parallel to the z-axis in the direction of the thread path in the region of the holding recess 36, whereby the thread catching hook grasps the thread(s) to be cut. When returning to the neutral position, the grasped thread(s) are cut off between the cutting edge of the cutting blade 45 and the counter blade 46.

[0058] The controlled drive of the cutting blade 45 is provided by a blade drive, which acts on a drive shaft 47 (see Fig. 3), which is a double-acting pneumatic cylinder. The movement of the cutting blade 45 is guided by a cam or guide not shown in the drawing.

[0059] Depending on the design of the sewing machine 3, it additionally has a thread finger device 48 with a thread finger 49 (see Fig. 7), which cooperates with the thread cutting device 44 for cutting the thread.

[0060] Fig. 7 shows an embodiment of such a thread finger device 48.

[0061] This is mounted on the sewing head 4. The thread finger 49 can be moved between the neutral position shown in Fig. 7 and a cutting preparation position using a pneumatic drive. In the cutting preparation position, after a sewing stop of the sewing machine 3, the thread finger 49 pulls the thread to be cut back into a position where it can be grasped by the cutting blade 45. After this retraction of the thread to be cut via the thread finger 49, the thread is then cut by the thread cutting device 44.

[0062] Depending on the design, the sewing system 1 can also comprise several pairs, each consisting of a sewing upper part 4 and a sewing lower part 5 that interacts with it to form the seam, i.e., several sewing machines similar to the sewing machine 3 described above. These multiple sewing machines can each be mounted on an associated frame similar to the frame 8. The various frames 8 of these multiple sewing machines 3 can be displaced relative to one another along the x-direction and / or along the y-direction via individually controllable displacement drives. Particularly when very large sewing areas are to be sewn, several sewing machines 3 can then process the sewing area in parallel. This parallel processing is controlled via the CNC control 2 of the sewing system 1.

[0063] Both the thread tension adjustment via the thread tension regulator 15 and the presser foot height adjustment via the adjustment drive 20 can be individually adjusted for each seam section via the CNC control 2. This can accommodate different sewing requirements depending on the section, for example, the section-dependent sewing of different numbers of layers of fabric and / or different fabric thicknesses and / or different stitch geometries. The CNC control 2 is in signal communication with the various drives and sensors of the sewing unit 1, which were explained above. The sewing unit 1 has a corresponding data bus system for this purpose. Signal transmission can take place via real-time Ethernet. One example of this is the EtherCAT protocol.

[0064] Via such an Ethernet system, signal data is forwarded to a production control system of sewing system 1 for production control, which is also known as a Manufacturing Execution System (MES).

Claims

Patent claims 1. Sewing system (1) with a CNC control (2), with at least one sewing machine (3), — with a fabric support plate (6) to define a fabric support (7), — with at least one sewing top (4) with a needle bar (9) that can be moved up and down in a controlled manner and with an upper thread guide for guiding an upper thread from an upper thread supply (10) to the needle bar (9), — with at least one sewing lower part (5) cooperating with the sewing upper part (4) to form the seam, with a controlled rotary drive hook (30), with a bobbin thread supply (31) in a gripper capsule (32), wherein the gripper (30) is rotatable about an axis (33) which runs parallel to the fabric support (7), wherein the gripper (30) has a diameter of at least 30 mm, wherein a capsule holding component (34) arranged in the area of ​​the fabric support (7) engages with the gripper capsule (32) such that the gripper capsule (32) does not rotate when the gripper (30) is rotated, — with a controlled capsule fan (37) for Displacement of the gripper capsule (32) between - — a neutral position and - — a ventilated position in which the space for a thread (43) between the gripper capsule (32) and the capsule holding component (34) is increased compared to the neutral position. Sewing system according to claim 1, characterized by a thread cutting device (44) for cutting off thread ends of the upper thread and / or the lower thread that protrude beyond a formed seam with a protrusion length of at most 15 mm. Sewing system according to claim 2, characterized in that the thread cutting device (44) has a cutting blade (45) which is driven by a double-acting pneumatic cylinder (47). Sewing system according to any one of claims 1 to 3, characterized in that the sewing upper part (4) has a housing arm section (27) which terminates in a housing head (26) in which the needle bar (9) is guided, wherein the housing head (26) in an operating configuration including the upper thread supply (10) has a width in a dimension (x) parallel to the material support (7) and perpendicular to the housing arm section (27) which is at most 300 mm.Sewing system according to claim 4, characterized in that the upper thread supply (10) is mounted on the housing head (26) in an extension of the housing arm section (27). Sewing system according to any one of claims 1 to 5, characterized in that the sewing machine (3) has a controllable thread tension device (15) for setting a thread tension of the upper thread and / or the upper thread.

7. Sewing system according to any one of claims 1 to 6, characterized in that the sewing machine (3) has a presser foot bar (19) with controllable foot height adjustment (20).

8. Sewing system according to any one of claims 1 to 7, with several sewing machines (3) which are supported by a common support frame of the sewing system (1) and are controllably displaceable relative to each other along at least one displacement dimension.

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