Sewing control method for a twin needle sewing machine

Abstract

The application discloses a sewing control method of a double-needle sewing machine, which comprises a sewing machine head and a control system. The sewing machine head is provided with a double-needle bar mechanism and a needle bar switching driving mechanism. The double-needle bar mechanism comprises two needle bars and a clutch structure for driving single-needle or double-needle sewing. Machine needles are arranged at the lower ends of the two needle bars. The needle bar switching driving mechanism comprises a sliding control rod for driving the clutch structure to switch the working state and a switching driver for controlling the working position of the sliding control rod. The switching driver is connected with the sliding control rod through a shifting rod. The control system comprises a sewing stitch storage module for storing input sewing patterns, a stitch corner identification module for identifying double-needle sewing corners with an angle of 30-145 degrees in the sewing patterns and outputting double-needle sewing corner coordinate points, and a switching driver control module for controlling the switching driver to switch the double-needle state into a single-needle state when sewing to the double-needle sewing corner coordinate points.

Description

Technical Field

[0001] This invention belongs to the field of sewing machine technology, specifically a sewing control method for a double-needle sewing machine. Background Technology

[0002] Patent No. 200810180910.7 discloses a single-needle switching device for a double-needle pattern sewing machine, including a switching lever; a switching plate; a sliding member; a clutch lever that contacts the sliding member when the needle bar moves up and down, isolating the needle bar from the sewing machine spindle; and a release pin that contacts the sliding member when the needle bar moves up and down, connecting the left and right needle bars to the sewing machine spindle. Operating the switching lever switches the machine to a position where the sliding member abuts against the clutch lever, or a position where the sliding member abuts against the release pin, thus achieving either a single-needle sewing state or a double-needle sewing state. This single-needle switching device includes a lever positioning mechanism that supports the switching lever to achieve three positions: a single-needle sewing state where the sliding member abuts against the clutch lever; a double-needle sewing state where the sliding member abuts against the release pin; and a neutral state where the sliding member abuts against both the clutch lever and the release pin. This patent disclosure has a certain drawback: the single-needle / double-needle sewing state requires manual operation of the lever positioning mechanism. When using a double-needle function to sew corner stitches, it can easily lead to messy stitches at the corners of the stitches. In addition, its transmission mechanism is relatively complex and the overall structure occupies a large space, so the structure needs to be improved. Summary of the Invention

[0003] This invention addresses the technical problem that existing sewing machines, when sewing patterns in double-needle mode, often experience messy stitches and affect sewing quality at angles ranging from 30 to 145 degrees. The invention provides a sewing control method for double-needle sewing machines that can automatically identify patterns sewn in double-needle mode and automatically switch to single-needle mode when sewing the corresponding coordinates in double-needle mode, thus avoiding messy stitches in patterned areas and improving sewing quality.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a sewing control method for a double-needle sewing machine, comprising a sewing machine head and a control system. The sewing machine head is provided with a double-needle bar mechanism and a needle bar switching drive mechanism. The double-needle bar mechanism includes two needle bars and a clutch structure for driving single-needle or double-needle sewing. The two needle bars are connected to the sewing machine spindle, and a needle is provided at the lower end of each of the two needle bars. The needle bar switching drive mechanism includes a sliding control lever for driving the clutch structure to switch working states and a switching driver for controlling the working position of the sliding control lever. The switching driver is connected to the sliding control lever through a lever. The control system includes a sewing stitch storage module for storing input sewing patterns, a stitch corner identification module for identifying double-needle sewing corners with angles from 30 degrees to 145 degrees in the sewing pattern and outputting the coordinates of the double-needle sewing corners, and a switching driver control module for controlling the switching driver to switch the double-needle state to the single-needle state when sewing reaches the coordinates of the double-needle sewing corner.

[0005] To optimize the above technical solution, the present invention also includes the following improved technical solutions.

[0006] The sewing machine head described above is equipped with a double thread clamping mechanism, which includes a thread-feeding block, a first thread clamping cylinder, and a second thread clamping cylinder. The thread-feeding block has a through-type first thread-feeding groove and a second thread-feeding groove, as well as a first thread clamping drive groove and a second thread clamping drive groove arranged perpendicularly to the first thread-feeding groove and the second thread-feeding groove. The first thread clamping drive groove is connected to the first thread-feeding groove, and the second thread clamping drive groove is connected to the second thread-feeding groove. The drive rod of the first thread clamping cylinder passes through the first thread clamping drive groove, and the drive rod of the second thread clamping cylinder passes through the second thread clamping drive groove.

[0007] The aforementioned control system is equipped with a double-thread clamping control module. When sewing reaches the corner coordinate point of double-needle sewing, the double-thread clamping control module controls the double-thread clamping mechanism to clamp the sewing thread to stop sewing.

[0008] The aforementioned switching driver consists of a first drive cylinder and a second drive cylinder connected in series.

[0009] The aforementioned switching driver consists of a first electromagnet and a second electromagnet connected in series.

[0010] The aforementioned switching driver is a control motor, which is connected to the lever via a linear transmission mechanism.

[0011] The end of the aforementioned sliding control lever has a connecting part that engages with one end of the lever; the lever has a limiting hole in the middle, and the sewing machine head is provided with a limiting member that is fitted into the limiting hole.

[0012] Compared with the prior art, the sewing control method of the double-needle sewing machine of the present invention addresses the issue that the stitches are prone to become messy when sewing at the angles of 30 to 145 degrees in the pattern using double needles. By controlling the system to automatically switch to single needle mode at the coordinate point of the angle to sew the angled areas, the sewing quality is improved. Attached Figure Description

[0013] Figure 1 This is a three-dimensional structural diagram of a sewing machine head.

[0014] Figure 2 This is a three-dimensional structural diagram of a sewing machine head from another perspective.

[0015] Figure 3 This is a cross-sectional view of a double clamping wire mechanism.

[0016] Figure 4 This is a comparison diagram of sewing stitch points at a corner angle θ of 35 degrees.

[0017] Figure 5 This is a comparison diagram of sewing stitch points at a corner θ of 90 degrees.

[0018] Figure 6 This is a comparison diagram of sewing stitch points at a corner angle θ of 145 degrees.

[0019] Figure 7 This is a three-dimensional structural diagram of a double-needle thread-cutting mechanism.

[0020] Figure 8 This is an exploded view of the double-needle thread-cutting mechanism. Detailed Implementation

[0021] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0022] Figures 1 to 8 The diagram shown is a structural schematic of the present invention.

[0023] The reference numerals in the attached drawings are as follows: sewing machine head 1, needle bar 2, needle 3, sliding control lever 4, connecting part 4a, first drive cylinder 5, second drive cylinder 6, fixing plate 7, cylinder mounting plate 8, lever 9, limiting hole 9a, threading block 10, first threading groove 10a, second threading groove 10b, first thread clamping drive groove 10c, second thread clamping drive groove 10d, first thread clamping cylinder 11, second thread clamping cylinder 12, first bottom shuttle mounting base 13, second... Bottom shuttle mounting base 14, first wire cutting drive motor 15, second wire cutting drive motor 16, first wire cutting fixed blade 17, first wire cutting movable blade 18, first wire cutting shaft 19, second wire cutting fixed blade 20, second wire cutting movable blade 21, first drive handle 22, second drive handle 23, first connecting rod 24, first sliding groove 25, first slider 26, first mounting groove 26a, third drive handle 27, first connecting pin 28, first wire clamping piece 29, rotating base 30.

[0024] like Figure 1 and Figure 2 The double-needle sewing machine of the present invention includes a sewing machine head 1 and a control system. The sewing machine head 1 is equipped with a double-needle bar mechanism. The double-needle bar mechanism includes two needle bars 2, which are connected to the sewing machine main shaft via needle bar holders and can move up and down. Two needles 3 are respectively provided at the lower ends of the two needle bars 2, and the needle bars 2 drive the corresponding needles 3 to move up and down. The double-needle bar mechanism has a clutch structure, which enables switching between single-needle and double-needle sewing.

[0025] A needle bar switching drive mechanism is provided on one side of the sewing machine head 1 for driving the clutch structure to change the working state. The needle bar switching drive mechanism includes a sliding control rod 4 that cooperates with the clutch structure and a switching driver for controlling the working position of the sliding control rod 4. The switching driver is connected to the sliding control rod 4 through a lever 9. By moving the sliding control rod 4, the single-needle or double-needle sewing state of the clutch structure is switched.

[0026] The switching driver can be a first drive cylinder 5 and a second drive cylinder 6 connected in series. The cylinder bodies of the first drive cylinder 5 and the second drive cylinder 6 are fixedly mounted on a cylinder mounting plate 8, which is movably mounted on one side of the sewing machine head 1. The drive rod of the first drive cylinder 5 is mounted on the outside of the sewing machine head 1 through a fixing plate 7. The cylinder body of the first drive cylinder 5 is connected to the cylinder body of the second drive cylinder 6. The drive rod of the second drive cylinder 6 is connected to a sliding control rod 4 through a lever 9. The end of the sliding control rod 4 has a connecting part 4a that engages with the lever 9.

[0027] The switching driver can be a first electromagnet and a second electromagnet connected in series. Alternatively, the switching driver can be a control motor, which is connected to the lever 9 via a linear transmission mechanism to drive the lever 9 to move.

[0028] The lever 9 has a limiting hole 9a in the middle, and the sewing machine head 1 is provided with a screw that cooperates with it. The limiting hole 9a is used to prevent the lever 9 from shaking up and down when it moves.

[0029] like Figure 3 As shown, a double thread clamping mechanism is provided on one side of the sewing machine head 1. The double thread clamping mechanism can effectively prevent the threads on the two needle bars 2 from interfering with each other and automatically and independently control the tension of each thread, which is conducive to sewing operations in a good environment.

[0030] The double-thread clamping mechanism includes a threading block 10, a first thread clamping cylinder 11, and a second thread clamping cylinder 12. The threading block 10 has a vertically arranged first threading groove 10a and a second threading groove 10b, through which two threads pass respectively. The threading block 10 also has a horizontally arranged first thread clamping drive groove 10c and a second thread clamping drive groove 10d. The first thread clamping drive groove 10c communicates with the first threading groove 10a, and the second thread clamping drive groove 10d communicates with the second threading groove 10b. The first thread clamping cylinder 11 and the second thread clamping cylinder 12 are horizontally mounted on both sides of the threading block 10. The drive rod of the first thread clamping cylinder 11 passes through the first thread clamping drive groove 10c, and the drive rod of the second thread clamping cylinder 12 passes through the second thread clamping drive groove 10d.

[0031] The first thread-clamping cylinder 11 and the second thread-clamping cylinder 12 can respectively clamp the thread passing through the first thread-passing groove 10a and the second thread-passing groove 10b, and control the tension of the thread on the two needle bars 2, making operation more flexible. In double-needle sewing mode, the thread on both needle bars 2 is in a relaxed state and does not need to be clamped. In single-needle sewing mode, the thread corresponding to the stopped needle bar 2 needs to be clamped to prevent the thread on the two needle bars 2 from tangling.

[0032] The sewing control method for the double-needle sewing machine in this embodiment addresses the technical problem that ordinary double-needle sewing machines cannot perfectly sew at the corners of double-needle patterns when sewing double-needle designs, resulting in messy stitches in the sewn pattern.

[0033] The control system includes a stitch storage module for storing input sewing patterns, a stitch corner identification module for identifying double-needle sewing corners with angles ranging from 30 degrees to 145 degrees in the sewing pattern and outputting the coordinates of the double-needle sewing corners, and a switching driver control module that controls a switching driver to switch the double-needle state to a single-needle state when sewing reaches a double-needle sewing corner coordinate point. The control system also includes a double-thread clamping control module, which controls a double-thread clamping mechanism to clamp the thread that has stopped sewing when sewing reaches a double-needle sewing corner coordinate point.

[0034] The data of the pattern to be sewn is stored in the sewing stitch storage module. In double-needle sewing mode, when the double-needle sewing machine reads a pattern to be sewn, the stitch corner recognition module identifies double-needle sewing corners between 30 and 145 degrees in the pattern and outputs the coordinates of the double-needle sewing corners. Angles less than 30 degrees or greater than 145 degrees, as well as various smoothly transitioned arcs, can be sewn well in double-needle mode without requiring the sewing control method of this technical solution.

[0035] The switching driver control module acquires the coordinates of the double-needle sewing corner output by the stitch corner recognition module. When sewing reaches this coordinate point, it controls the switching driver to switch the sewing machine head 1 from double-needle mode to single-needle mode. This coordinate point can be the coordinate point of the sharpest part of the angle, or the coordinate point of the sharpest part of the angle plus an adjacent sewing coordinate point. The sewing machine head 1 automatically switches to single-needle mode to complete the sewing of the sharp corner.

[0036] When the needle bar switching drive mechanism controls the double needle bar mechanism to adjust to the single needle state, it selectively drives one side of the needle bar 2 to stop working. The needle bar 2 located inside the corner of the double needle stitch stops working, while the needle bar 2 located outside the corner of the double needle stitch sews at that coordinate point in single needle state. At the same time, the double thread clamping mechanism clamps the thread corresponding to the stopped needle bar 2 to prevent the thread tension from becoming uncontrollable and causing a decrease in the sewing quality of subsequent double needle state.

[0037] After sewing machine head 1 finishes sewing the coordinate point of the sharp corner in single-needle mode, the needle bar switching drive mechanism controls the double needle bar mechanism to adjust to double-needle mode, and continues to sew in double-needle mode according to the pattern until the next recognized double-needle sewing corner coordinate point is identified, then switches to single-needle mode or the sewing ends.

[0038] Figures 4 to 6 This is a comparison diagram of the needle positions after the double-needle sewing machine in this embodiment sews on white paper without thread. For example... Figure 4 As shown, the angle θ of the corner of the sewing pattern is 35 degrees at this time. Figure 4 Part a in the diagram represents the stitch points in the uncompensated state. After sewing a section in double-needle mode, the sewing machine head 1 continues to sew the corner section in double-needle mode along needle points 31, 32, and 33 as shown in the diagram. Figure 4 In part a, needle point 31 is the first stitch at the corner, needle point 32 is the stitch at the corner, and needle point 33 is the stitch after the corner. Because it is always in double-needle sewing mode, the needle points sewn at the corner will protrude from the sewing pattern, and the stitches will be messy and not very beautiful. Figure 4Part b describes the stitch positions after activating the sewing control method of this technical solution. The sewing machine head 1 sews sequentially along needle points 34, 35, and 36 as shown in the diagram. Needle point 34 is the stitch before the corner begins; needle point 35 is the coordinate point of the sharpest part of the angle, where the sewing machine head 1 automatically switches to single-needle mode for the first stitch; needle point 36 is the stitch after the corner ends, at which point the sewing machine head 1 automatically switches to double-needle mode for subsequent sewing. At the corner, the sewing machine head 1 switches from double-needle mode to single-needle mode, and the needle bar 2 located inside the double-needle stitch corner stops working. The sewing is completed by the needle bar 2 outside the double-needle stitch corner. After sewing, all needle points are on the sewing pattern, resulting in a more aesthetically pleasing sewing effect.

[0039] like Figure 5 As shown, the angle θ of the corner of the pattern is 90 degrees at this time. Figure 5 Part a in the diagram represents the stitch points in the uncompensated state. After sewing a section in double-needle mode, the sewing machine head 1 continues to sew along needle points 37, 38, and 39 in double-needle mode. Needle point 37 is the stitch before the corner begins, needle point 38 is the stitch at the sharp end of the corner, and needle point 39 is the stitch after the corner ends. Because it is always in double-needle sewing mode, the needle points sewn at the corner will protrude from the sewing pattern, and the stitches will be messy and not very aesthetically pleasing. Figure 5 Part b shows the stitch points after activating the sewing control method of this technical solution. The sewing machine head 1 sews sequentially along needle points 40, 41, and 42. Needle point 40 is the stitch before the corner begins, completed in double-needle mode. Needle point 41 is the coordinate point of the sharpest angle; the sewing machine head 1 automatically switches to single-needle mode to complete the stitching at needle point 41. Needle point 42 is the stitch after the corner ends; the sewing machine head 1 automatically switches to double-needle mode and continues subsequent sewing. At needle point 41, this sewing control method switches the double-needle mode to single-needle mode. The needle bar 2 located inside the double-needle stitch corner stops working, and the needle bar 2 located outside the double-needle stitch corner adds a stitch, resulting in a more aesthetically pleasing sewing effect.

[0040] like Figure 6 As shown, the angle θ of the corner of the pattern is 145 degrees at this time. Figure 6 Part 'a' in the diagram shows the stitch points in the uncompensated state. After sewing a section in double-needle mode, sewing machine head 1 continues to sew the corner along needle points 43, 44, and 45 as shown in the diagram, also in double-needle mode. Needle point 43 is the stitch before the corner begins, needle point 44 is the stitch at the sharp part of the corner, and needle point 45 is the stitch after the corner ends. In double-needle mode, the stitches at the corner are relatively loose, resulting in messy and unsightly stitches. Figure 6Part b shows the stitch points after the sewing control method of this technical solution is activated. The sewing machine head 1 sews sequentially along needle points 46, 47, and 48 as shown in the diagram. Needle point 46 is the first stitch at the beginning of the corner; needle point 47 is the coordinate point of the sharpest part of the angle, and the sewing machine head 1 automatically switches to single-needle mode to sew this stitch; needle point 48 is the last stitch after the corner ends, at which point the sewing machine head 1 automatically switches to double-needle mode for subsequent sewing. At needle point 47 at the corner, the sewing machine head 1 switches from double-needle mode to single-needle mode. The needle bar 2 located inside the corner of the double-needle stitch stops working, and the needle bar 2 located outside the corner of the double-needle stitch sews needle point 47, making the sewing pattern more closely match the designed pattern and resulting in a more aesthetically pleasing sewing effect.

[0041] like Figure 7 and Figure 8 As shown, the double-needle sewing machine of the present invention further includes a double-needle thread-cutting mechanism disposed below the worktable, which corresponds vertically to the sewing machine head 1 above the worktable. The double-needle thread-cutting mechanism includes a first bobbin mounting base 13, a second bobbin mounting base 14, a first thread-cutting drive motor 15, and a second thread-cutting drive motor 16 mounted on a rotating base 30. The first bobbin mounting base 13 is provided with a first fixed thread-cutting blade 17 and a first movable thread-cutting blade 18. The first bobbin mounting base 13 is provided with a first thread-cutting shaft 19 for driving the first movable thread-cutting blade 18. The drive shaft of the first thread-cutting drive motor 15 is rotatably connected to the first thread-cutting shaft 19. The second bobbin mounting base 14 is provided with a second fixed thread-cutting blade 20 and a second movable thread-cutting blade 21. The second bobbin mounting base 14 is provided with a second thread-cutting shaft for driving the second movable thread-cutting blade 21. The drive shaft of the second thread-cutting drive motor 16 is rotatably connected to the second thread-cutting shaft.

[0042] The drive shaft of the first wire cutting drive motor 15 is provided with a first drive handle 22, and the lower end of the first wire cutting shaft 19 is provided with a second drive handle 23. The first drive handle 22 is connected to the second drive handle 23 through a first connecting rod 24. The first wire cutting drive motor 15 drives the first wire cutting shaft 19 to rotate through the first drive handle 22, the first connecting rod 24, and the second drive handle 23.

[0043] The first bottom shuttle mounting base 13 is provided with a first sliding groove 25, and a first slider 26 is provided in the first sliding groove 25. The first wire-cutting moving blade 18 is fixedly connected to the first slider 26. The upper end of the first wire-cutting shaft 19 is provided with a third driving handle 27 that is movably connected to the first slider 26. The first slider 26 is provided with a first mounting groove 26a, and the end of the third driving handle 27 is provided with a first connecting pin 28. The first connecting pin 28 is movably installed in the first mounting groove 26a. The third driving handle 27 rotates around the first wire-cutting shaft 19, and the third driving handle 27 drives the first slider 26 to slide along the first sliding groove 25, thereby controlling the movement of the first wire-cutting moving blade 18.

[0044] The drive shaft of the second wire cutting drive motor 16 is provided with a fourth drive handle, and the lower end of the second wire cutting shaft is provided with a fifth drive handle. The fourth drive handle is connected to the fifth drive handle through a second connecting rod. The second wire cutting drive motor 16 drives the second wire cutting shaft to rotate through the fourth drive handle, the second connecting rod, and the fifth drive handle.

[0045] The second bottom shuttle mounting base 14 is provided with a second sliding groove, and a second slider is provided in the second sliding groove. The second wire-cutting moving blade 21 is fixedly connected to the second slider. The upper end of the second wire-cutting shaft is provided with a sixth driving handle that is movably connected to the second slider. The second slider is provided with a second mounting groove, and the end of the sixth driving handle is provided with a second connecting pin. The second connecting pin is movably installed in the second mounting groove. The sixth driving handle rotates around the second wire-cutting shaft, and the sixth driving handle drives the second slider to slide along the second sliding groove, thereby controlling the movement of the second wire-cutting moving blade 21.

[0046] Below the first thread-cutting blade 18 is a first thread-clamping plate 29, which is fixedly installed on the first bottom shuttle mounting base 13. When the first thread-cutting blade 18 and the first thread-cutting fixed blade 17 work together to cut the thread, the thread end of the first bottom shuttle is clamped between the first thread-cutting blade 18 and the first thread-clamping plate 29, making it convenient for the next sewing.

[0047] Below the second thread-cutting blade 21 is a second thread-clamping plate, which is fixedly installed on the second bottom shuttle mounting base 14. When the second thread-cutting blade 21 and the second thread-cutting fixed blade 20 cooperate to cut the thread, the thread end of the second bottom shuttle is clamped between the second thread-cutting blade 21 and the second thread-clamping plate, making it convenient for the next sewing.

[0048] The preferred embodiments of the present invention have been described, and various changes or modifications made by those skilled in the art will not depart from the scope of the present invention.

Claims

1. A sewing control method for a double-needle sewing machine, comprising a sewing machine head (1) and a control system, characterized in that: The sewing machine head (1) is provided with a double needle bar mechanism and a needle bar switching drive mechanism. The double needle bar mechanism includes two needle bars (2) and a clutch structure for driving single-needle or double-needle sewing. The two needle bars (2) are connected to the sewing machine spindle, and a needle (3) is provided at the lower end of each of the two needle bars (2). The needle bar switching drive mechanism includes a sliding control lever (4) for driving the clutch structure to switch working states and a switching driver for controlling the working position of the sliding control lever (4). The switching driver is connected to the sliding control lever (4) through a lever (9). The control system includes a sewing stitch storage module for storing input sewing patterns, a stitch corner identification module for identifying double-needle sewing corners with angles from 30 degrees to 145 degrees in the sewing pattern and outputting the coordinates of the double-needle sewing corners, and a switching driver control module for controlling the switching driver to switch the double-needle state to the single-needle state when sewing to the coordinates of the double-needle sewing corner.

2. A sewing control method applied to a double-needle sewing machine as described in claim 1, characterized in that: The sewing machine head (1) is provided with a double thread clamping mechanism, which includes a thread-feeding block (10), a first thread clamping cylinder (11), and a second thread clamping cylinder (12). The thread-feeding block (10) has a through-type first thread-feeding groove (10a) and a second thread-feeding groove (10b), and a first thread clamping drive groove (10c) and a second thread clamping drive groove (10d) arranged perpendicularly to the first thread-feeding groove (10a) and the second thread-feeding groove (10b). The first thread clamping drive groove (10c) is connected to the first thread-feeding groove (10a), and the second thread clamping drive groove (10d) is connected to the second thread-feeding groove (10b). The drive rod of the first thread clamping cylinder (11) passes through the first thread clamping drive groove (10c), and the drive rod of the second thread clamping cylinder (12) passes through the second thread clamping drive groove (10d).

3. A sewing control method applied to a double-needle sewing machine as described in claim 2, characterized in that: The control system is equipped with a double-thread clamping control module. When sewing reaches the corner coordinate point of double-needle sewing, the double-thread clamping control module controls the double-thread clamping mechanism to clamp the sewing thread that has stopped sewing.

4. The sewing control method for a double-needle sewing machine according to claim 1, characterized in that: The switching driver consists of a first drive cylinder (5) and a second drive cylinder (6) connected in series.

5. The sewing control method for a double-needle sewing machine according to claim 1, characterized in that: The switching driver consists of a first electromagnet and a second electromagnet connected in series.

6. The sewing control method for a double-needle sewing machine according to claim 1, characterized in that: The switching driver is a control motor, which is connected to the lever (9) via a linear transmission mechanism.

7. The sewing control method for a double-needle sewing machine according to claim 1, characterized in that: The end of the sliding control lever (4) has a connecting part (4a) that engages with one end of the lever (9); the lever (9) has a limiting hole (9a) in the middle, and the sewing machine head (1) is provided with a limiting member that is installed in conjunction with the limiting hole (9a).

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