Sewing unit

Abstract

A sewing unit (1) has a CNC controller (2) and a sewing machine (3). The sewing machine (3) is provided with a workpiece bed plate (6), an upper sewing part (4) and a lower sewing part (5). The lower sewing section (5) has a curved needle which can be rotationally driven in a controlled manner and has a base thread supply in a curved needle cartridge. The curved needle is rotatable about an axis extending parallel to the workpiece bed. And the diameter of the curved needle is at least 30mm. A magazine retaining member arranged in the region of the workpiece bed engages with the curved needle magazine such that the curved needle magazine does not rotate therewith during rotation of the curved needle. The lower sewing part is provided with a shuttle box lifter which can be driven in a controlled mode so as to enable the looper shuttle box to move between a neutral position and an open position, and in the open position, the free space of the thread between the looper shuttle box and the shuttle box keeping part is increased compared with the neutral position. This forms a sewing unit that ensures mass production with a high level of overall unit efficiency even when thick threads are used.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

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

[0003] The invention relates to a sewing unit. Background Art

[0004] Sewing machines of this type are used commercially for producing line 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 C1 discloses a sewing machine for fixing workpieces with large surface areas. DE2 247 050 A discloses a thread take-up lever for a sewing machine, preferably for a multi-needle double-lock sewing machine.

[0005] The object of the present invention is to develop a sewing unit which ensures high-volume production with a high level of overall unit efficiency even when using thick threads. Summary of the invention

[0006] This object is achieved according to the invention by a sewing unit having the features of claim 1 .

[0007] According to the present invention, it is recognized that the shuttle box lifter (shuttle box opener and closeer) disclosed in DE 100 25 851 C1 and DE 32 44 946 C1 can be improved so that even when equipped with a very large looper, it can be used in conjunction with a correspondingly larger bottom line feeder. An example of a larger looper is shown in DE 20 2013 005 112 U1. The free space of the line between the looper shuttle box and the shuttle box holding part, which is enlarged by the shuttle box lifter, reduces the line friction in the looper side workpiece bed area during the sewing operation. This reduced line friction makes it possible to use even NM 20 or thicker thick lines. Such thick upper thread and / or bottom thread can be sewn at a sewing speed of 2000, 2200, 2500 or even 2800 stitches per minute.

[0008] The lower sewing section can be designed to use a semi-automatic or fully automatic bobbin replacement system to carry out corresponding automatic lower thread feeder replacement. This further increases the efficiency of the entire sewing unit.

[0009] The sewing unit can be used to produce seams for the automotive industry, such as instrument panels, vehicle seats, seat belts or airbag seams.

[0010] A C-shaped frame or even other frame geometries may be used to hold the upper and lower sewing sections of the sewing machine in a sewing unit.

[0011] The needle bar can move up and down along the z-coordinate of the sewing unit coordinate system. In this case, the upper sewing part together with the lower sewing part and / or the workpiece bed can be designed to move along the x-coordinate and / or the y-coordinate by a correspondingly controlled drive. Therefore, the sewing unit can be designed with a movable sewing machine and / or a movable workpiece bed.

[0012] The sewing machine can be designed to monitor the remaining thread amount of the upper thread and / or the lower thread. The sewing machine can be designed with at least one vibration sensor for monitoring maintenance requirements, in particular bearings of the sewing unit, in particular the upper sewing part and / or the lower sewing part. The upper sewing part can be designed with needle cooling.

[0013] The wire cutting device according to claim 2 forms a neater seam. A wire cutting device as known from EP 2300 654 B1 can be used. The excess length achieved with the wire cutting device can be up to 15 mm, but can also be shorter, for example 12 mm or 10 mm. The starting line and / or the end line of the formed seam can be cut off. A thread finger can cooperate with the wire cutting device when the thread is cut. A corresponding process can include grabbing the thread to be cut with the thread finger after sewing stops in order to pull the thread, and then cutting the grabbed thread by the wire cutting device after the thread has been pulled.

[0014] An embodiment of the wire cutting device according to claim 3 has proven to be valuable in order to be able to produce the shortest possible excess length in a reproducible process. The cutting blade can be guided by a cam or a track.

[0015] The narrow head design for the upper sewing section according to claim 4 enables multiple sewing machines in the sewing unit to cooperate with each other in parallel so as to work in a large sewing area. The width of the head of the upper sewing section can reach 280 mm, 250 mm or even less. This width is usually at least 200 mm.

[0016] The mounting of the upper thread feeder according to claim 5 enables a particularly narrow width of the upper sewing section in an operating embodiment. The upper thread feeder can be aligned with the housing arm.

[0017] A good control of the seam formation can be achieved with the thread tension adjustment device according to claim 6. The thread tension can be adjusted in different ways for individual seam sections of the entire seam to be produced.

[0018] The presser foot according to claim 7 allows the sewing process to be adapted to different workpiece conditions. The adjustability of the presser foot can be used individually for individual seam sections of the entire seam to be produced and thus the specific requirements of the respective section can be taken into account. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The exemplary embodiments of the present invention will be explained in detail below with reference to the accompanying drawings. In the accompanying drawings:

[0020] Figure 1 A side view schematically illustrates the main components of a CNC-controlled sewing unit including an upper sewing section and a lower sewing section cooperating therewith;

[0021] Figure 2 is Figure 1 A perspective view of an upper sewing portion used in a sewing unit of the present invention;

[0022] Figure 3 is Figure 1 A perspective view of a lower sewing section used in a sewing unit of the present invention;

[0023] Figure 4 is an end view of a detail of a lower sewing section including a shuttle box lifter which can be controlled and driven;

[0024] Figure 5 The lower sewing portion is shown obliquely from above, with the looper shuttle box in a neutral position relative to the shuttle box holding component;

[0025] Figure 6 Similar to Figure 5 The illustration shows the position of the looper box opened relative to the neutral position due to the action of the box lifter, which position is also called the open position; and

[0026] Figure 7 An exemplary embodiment of an upper sewing part is shown in a side view, which has a thread guide finger for pulling back the upper thread after sewing the seam and before cutting the thread. DETAILED DESCRIPTION

[0027] The sewing unit 1 has Figure 1 Schematically shown in FIG. 2 are a CNC controller 2 and a sewing machine 3. The sewing machine 3 has an upper sewing part 4 and a lower sewing part 5.

[0028] The sewing unit 1 also has a workpiece bed plate 6 which provides a workpiece bed lying on a workpiece bed plane 7 .

[0029] The upper sewing section 4 and the lower sewing section 5 of the sewing machine 3 are mounted on a frame 8 of the sewing machine 3 of the sewing unit 1 .

[0030] The Cartesian xyz coordinate system is used below to more easily describe the positional relationship. Figure 1In the figure, the x-axis extends perpendicular to the plane of the drawing and extends out of the plane. The y-axis is Figure 1 The z-axis extends horizontally to the right. Figure 1 Extending vertically upward.

[0031] The frame 8 is substantially C-shaped, so that the usable sewing surface in the xy plane, in particular in the y direction, can extend over a large area of ​​more than 1000 mm x 1000 mm.

[0032] During the sewing process, the workpiece bed 6 is displaced in the x-direction and / or in the y-direction relative to the upper sewing part 4 on the one hand and to the lower sewing part 5 on the other hand. Depending on the design of the sewing unit 1, this relative displacement may be such that the frame 8 of the sewing machine 3 is moved relative to the workpiece bed 6, which is therefore stationary, or the workpiece bed 6 is moved relative to the frame 8, which is then stationary. In another variant, the frame 8 and the workpiece bed 6 can be displaced relative to each other in the x-direction and / or in the y-direction.

[0033] Figure 2 The upper sewing part 4 is shown in detail. The upper sewing part 4 has a needle bar 9, which can be moved up and down in a controlled manner along the z direction. According to the design of the upper sewing part 4, a needle bar 9 is provided for guiding the sewing needle (not shown) held thereon. Figure 2 The needle bar 9 (shown in FIG. 1 ) can be cooled.

[0034] The upper sewing part 4 has an upper thread guide, which is used to guide the upper thread from an upper thread supply 10 in the form of a thread drum to the needle bar 9. Figure 2 Not shown along the upper thread guide. The upper thread guide comprises a thread gripper 11 which is arranged close to the needle bar 9 and is activated by means of a gripper drive 12 which may be of pneumatic design.

[0035] In the area of ​​the thread clamp 11, a thread break sensor 13 can be arranged, which can be designed as an optical sensor. Through such a thread break sensor 13, it can be monitored whether there is still upper thread being supplied to the needle bar 9.

[0036] The upper thread guide also includes a thread take-up lever 14 and a thread tension adjustment device 15, whereby the thread tension of the upper thread can be set. According to the design of the upper sewing part 4, a thread tension sensor 16 can be arranged in the region of the thread take-up lever 14, by means of which the thread tension of the upper thread can be monitored.

[0037] The movement of the needle bar 9 and the thread take-up lever 14 is driven in a controlled manner by means of a sewing drive motor 17. The sewing tools of the sewing machine 3 can be manually brought close to a certain position by means of a hand wheel 18 of the upper sewing section 4. The rotation axis of the hand wheel 18 is parallel to the x direction, i.e., perpendicular to the C plane (yz plane) of the frame 8 and also perpendicular to the extension direction of the arm axis (extending in the y direction) of the upper sewing section 4, and the drive of the needle bar 9 and the thread take-up lever 14 comes from the rotational movement of the hand wheel 18.

[0038] The upper sewing portion 4 can also be equipped with Figure 2 Such a presser foot is held on a presser foot bar 19. An adjusting drive 20, which is designed as a servo motor or a pneumatic drive, is used to adjust the height of the presser foot bar 19 along the z direction.

[0039] A pneumatic fan drive 21 may be provided to provide flexibility to the presser foot bar 19 .

[0040] Another monitoring sensor 22 of the upper sewing section 4 monitors the “top dead center” position of the needle bar 9. Therefore, the monitoring sensor 22 can be designed as an optical sensor.

[0041] In order to monitor the supporting condition of the upper sewing part 4, the component may include a vibration sensor 23. Once the vibration of the upper sewing part 4 sensed by the vibration sensor 23 exceeds the tolerance value, a signal may be output to prepare for maintenance of the sewing machine 3.

[0042] The upper sewing part 4 has a fill level sensor 24 in order to monitor the lubricant level, in particular the oil level, for lubricating the moving parts of the upper sewing part 4 .

[0043] An upper line fill level sensor 25 , which may be an optical sensor, is used to monitor the fill level of the upper line supply 10 .

[0044] The upper thread feeder 10 is mounted on the machine head 26 of the upper sewing part 4. This mounting position of the upper thread feeder 10 is located in the extension direction of the housing arm 27 of the upper sewing part 4, which extends in the y direction and ends at the machine head 26.

[0045] The needle bar 9 and the presser foot bar 19 are guided in the machine head 26 .

[0046] According to the design of the upper sewing part 4, the head 26 in an operating configuration including the upper thread feeder 10 has a width in the x dimension (i.e. the extension dimension y parallel to the workpiece bed 7 and perpendicular to the housing arm 27) which can be up to 300 mm and can reach, for example, 280 mm or even 250 mm.

[0047] Alternatively, the upper thread feeder 10 may also be mounted on the frame 8 or even arranged beside the machine head 26, such as Figure 1 and Figure 7 shown.

[0048] Furthermore, the sewing unit 1 comprises a reading device 28 for the upper thread type (in Figure 2 ) The reading device is provided together with the online supplier 10. The reading device 28 can be, for example, a bar code reader.

[0049] Figure 3 An embodiment of a lower sewing section 5 of a sewing machine 3 of a sewing unit 1 is shown. The lower sewing section 5 cooperates with the upper sewing section 4 to form a seam. To this end, the lower sewing section 5 has a looper 30, which can be driven rotationally in a controlled manner, and has a bottom thread feeder in a looper bobbin 31, which is accommodated in a looper shuttle box 32. The looper 30 has a looper tip, which cooperates with a sewing needle fastened to a needle bar 9 of the upper sewing section 4 to form a stitch or seam. In this way, lock seams, in particular double lock seams, can be produced.

[0050] Including the bending needle tip, the bending needle 30 can be rotated about an axis of rotation 33 extending parallel to the y-axis. This axis of rotation 33 extends parallel to the workpiece bed 7, ie parallel to the xy plane.

[0051] The receiving area in the looper magazine 32 for the looper bobbin 31 with the lower thread feeder has an outer diameter measured perpendicularly to the rotation axis 33 which is greater than 30 millimeters.

[0052] In the area of ​​the workpiece bed 6, a shuttle box holding component (see Figure 5 and Figure 6 ) is fixedly connected to the frame 35 of the lower sewing part 5. The retaining web 34 engages with the retaining hole 36 of the looper shuttle box 32 so that when the looper 30 rotates around the rotation axis 33, the looper shuttle box 32 does not rotate therewith. In the circumferential direction around the rotation axis 33, the retaining hole 36 is wider than the retaining web 34, and therefore, according to the circumferential position of the retaining hole 36 relative to the retaining web 34, there is a gap, that is, a free space, in this circumferential direction.

[0053] The lower sewing section 5 has a shuttle box lifter (shuttle box opener) 37 (see Figure 4 ), which can be driven in a controlled manner to bring the looper shuttle box 32 into a neutral position (which is Figure 5 ) and the raised (open) position (which is Figure 6 The figure shows the displacement between .

[0054] The lever point of the shuttle box lifter 37 cooperates with the reverse side of the looper shuttle box 32 to displace the shuttle box 32 in the circumferential direction.

[0055] The rotation drive of the looper 30 and the drive of the shuttle box lifter 37 both come from the sewing drive 38 of the lower sewing part 5.

[0056] The needle length during seam formation may range between 2 mm and 10 mm.

[0057] The lower sewing part 5 also has a bottom thread filling level sensor 39, a monitoring sensor 20 for monitoring the initial position of the bending needle tip of the bending needle 30, a vibration sensor 41 for monitoring the supporting condition of the bearing of the lower sewing part 5, and a lubricant level sensor 42, and their structure and working method are the same as the sensors explained above with reference to the upper sewing part 4.

[0058] exist Figure 6 In the open position of the looper shuttle box 32, Figure 5 Compared with the position in Figures 4 to 6 In the embodiment, this position is offset by several degrees in the counterclockwise direction relative to the retaining web 34 in the circumferential direction of the rotation axis 33. Figure 6 On the left side, in the open position, a free space that is larger than that in the neutral position is created between the retaining web 34 and the retaining hole 36 of the curved needle shuttle box 32. This free space is provided to allow the bottom line 43 to pass between the curved needle shuttle box 32 and the bedside components (especially the retaining web 34).

[0059] exist Figure 6 In the open position of the sewing machine 3, this increased free space reduces the thread friction during the sewing operation of the sewing machine 3. Even with a thick thread 43 with a thread weight of at least 50 grams per 1000 meters (50 tex = 20 NM), sewing can be performed at an operating speed of at least 2000 stitches per minute of the sewing machine 3. The operating speed can be, for example, 2200, 2400 or even 2500 stitches per minute, and can be higher. The thread can also be thicker or heavier than 50 tex, for example 77 tex (= 13 NM).

[0060] The upper thread and / or the lower thread may be a polyamide thread and / or a nylon thread. The upper thread and the lower thread may be different colors.

[0061] The looper 30 is attached to the frame 35 of the lower sewing part 5, in particular in such a way that an automatic replacement system for replacing the looper bobbin 31 (ie the lower thread feeder) can be implemented.

[0062] Using the sewing unit 1 , seams can be produced for the automotive industry, such as seams for dashboards, vehicle seats, seat belts or airbags.

[0063] In addition, the lower sewing part 5 has a wire cutting device 44, the components of which are Figure 5 and Figure 6The thread cutting device 44 is used to cut off the thread ends of the upper thread or the lower thread protruding above the seam formed by the sewing machine 3. After the thread cutting device 44 cuts off the thread ends, a cut thread end with an excess length of no more than 15 mm is left above the formed seam. This excess length can also be shorter, for example, up to 12 mm or 10 mm. The thread end can be the starting line or the ending line of the seam.

[0064] The wire cutting device 44 has a cutting blade 45, the wire catching hook and its blade are arranged at Figure 5 and Figure 6 The cutting blade 45 is blocked by the opposing blade 46 of the wire cutting device 44. Figure 5 The cutting position is shown in Figure 6 36. In order to cut the wire, the cutting blade 45 is pivoted about a pivot axis (extending parallel to the z-axis) in the direction of the wire extending in the region of the holding hole 36, wherein the wire catcher hook catches the wire to be cut. When returning to the neutral position, the caught wire is cut between the cutting edge of the cutting blade 45 and the opposing blade 46.

[0065] The blade driver is used to control the driving of the cutting blade 45 and acts on the driving shaft 47, see Figure 3 , which is a double-acting cylinder. The movement of the cutting blade 45 is guided by a cam or track not shown in the drawings.

[0066] According to the design of the sewing machine 3, this machine also includes a guide 49 (see Figure 7 ) of the wire finger device 48, which cooperates with the wire cutting device 44 to cut the wire.

[0067] Figure 7 An embodiment of such a conductor finger device 48 is shown. It is mounted on the upper sewing part 4. The conductor finger 49 can be moved in a pneumatic manner using a pneumatic drive. Figure 7 In the cutting preparation position, after the sewing machine 3 stops sewing, the wire finger 49 pulls the wire to be cut back to a position where it can be caught by the cutting blade 45. After the wire finger 49 pulls the wire to be cut back, the wire is cut by the wire cutting device 44.

[0068] According to the design, the sewing unit 1 can also include a plurality of pairs, each pair consisting of an upper sewing part 4 and a lower sewing part 5 cooperating therewith to form a seam, i.e. a plurality of sewing machines similar to the above-mentioned sewing machine 3. These sewing machines can each be mounted on a frame similar to the frame 8. The individual frames 8 of these sewing machines 3 can be displaced relative to each other along the x-direction and / or y-direction by means of respective individually activated displacement devices. In particular, in the case of very large sewing areas to be sewn, a plurality of sewing machines 3 can work on the sewing area in parallel. This parallel operation is controlled by the CNC controller 2 of the sewing unit 1.

[0069] The adjustment of the thread tension by means of the thread tension regulator 15 and the adjustment of the height of the presser foot by means of the adjustment drive 20 can be adjusted individually for each seam section in a controlled manner by means of the CNC controller 2. This allows for different sewing requirements depending on the section, such as section-related sewing of different workpiece layers and / or different workpiece thicknesses and / or different stitch geometries.

[0070] The CNC controller 2 communicates signals with various drivers and sensors of the sewing unit 1, as described above. For this purpose, the sewing unit 1 has a corresponding data bus system. Signal transmission can be achieved via real-time Ethernet. An example of this is the Ethernet CAT protocol.

[0071] Through such an Ethernet system, signal data is transmitted to the production management system of the sewing unit 1 to achieve production control, which is also called a manufacturing execution system (MES).

Claims

1. A sewing unit (1) - having a CNC controller (2), - having at least one sewing machine (3), -- having a workpiece bed plate (6) for providing a workpiece bed (7), - having at least one upper sewing section (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 the upper thread from an upper thread supply (10) to the needle bar (9), - having at least one lower sewing section (5) cooperating with the upper sewing section (4) to form a seam and having a looper (30) which can be driven in rotation in a controlled manner and has a bottom thread feeder (31) located in a looper shuttle box (32), wherein the looper (30) can rotate about an axis (33) extending parallel to the workpiece bed (7), wherein the diameter of the looper (30) is at least 30 mm, wherein a shuttle box holding part (34) arranged in the area of ​​the workpiece bed (7) engages with the looper shuttle box (32) so that during the rotation of the looper (30), the looper shuttle box (32) does not rotate with it, - having a shuttle box lifter (37) which can be driven in a controlled manner to move the looper shuttle box (32) in a ---Neutral position and ---displacement between an open position, in which the free space for the line (43) between the hook shuttle box (32) and the shuttle box holding member (34) is increased compared to the neutral position.

2. The sewing unit according to claim 1, characterized in that A thread cutting device (44) is used to cut off thread ends of the upper thread and / or the lower thread, the thread ends protruding above the formed seam and having a maximum excess length of 15 mm.

3. The sewing unit according to claim 2, characterized in that: The wire cutting device (44) comprises a cutting blade (45) which is driven in a controlled manner by means of a double-acting cylinder (47).

4. The sewing unit according to any one of claims 1 to 3, characterized in that The upper sewing section (4) comprises a housing arm (27) terminating in a machine head (26), wherein the needle bar (9) is guided, wherein the machine head (26) in an operating embodiment including the upper thread feeder (10) has a maximum width of 300 mm in a dimension (x) parallel to the workpiece bed (7) and perpendicular to the housing arm (27).

5. The sewing unit according to claim 4, characterized in that The upper thread feeder (10) is mounted on the machine head (26) as an extension of the housing arm (27).

6. The sewing unit according to any one of claims 1 to 5, characterized in that The sewing machine (3) comprises an activatable thread tension adjustment device (15) for setting the thread tension of the upper thread.

7. The sewing unit according to any one of claims 1 to 6, characterized in that The sewing machine (3) comprises a presser foot lever (19) with an activatable presser foot height adjuster (20).

8. A sewing unit according to any one of claims 1 to 7, comprising a plurality of sewing machines (3), which are supported by a common support frame of the sewing unit (1) and can be displaced relative to each other in a controlled driven manner along at least one displacement dimension.

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