JP2010057529A - Thread cutting method for single chain stitch sewing machine and device therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thread cutting method for a single chain stitch sewing machine provided with a function of evenly cutting a thread end part at the start of sewing short, and an device therefor. <P>SOLUTION: The thread end part 4a at the start of sewing, which is held between a leaf spring 10 for holding the thread and a first movable knife 11 at the start of the sewing and remains on the upper surface side of a workpiece W is brought into contact with a second fixed knife 13 disposed at the upper part of a needle plate 2 at the second stitch from the start of the sewing or the stitch after the second stitch, and is cut at a position near the upper surface of the workpiece W. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thread cutting method and apparatus for a single-ring stitch sewing machine having a function of cutting and aligning needle threads at the start of sewing.

  2. Description of the Related Art Conventionally, a single-ring stitch sewing machine including a thread cutting device that automatically cuts a sewing thread after completion of sewing is well known (see, for example, Patent Documents 1 and 2).

JP-A-62-281995 JP 2001-353385 A

However, in the single ring sewing machine, since the sewing thread is cut by the thread cutting device on the lower surface side of the needle plate after the sewing is finished, the thread end that has been cut is cut with the wiper member on the upper surface side of the needle plate. A thread wiping mechanism (wiper device) is required for lifting the knives. Further, in a single-ring-stitched cardboard sewing machine, the sewing machine bed has an elongated cylinder shape to cope with various cardboard sizes, so that it is difficult to arrange a complicated thread cutting system below the needle plate.
For this reason, in order to omit the thread wiper mechanism and to simplify the incorporation of the thread trimming system into an elongated cylinder-shaped sewing machine bed of a single-ring-stitched cardboard sewing machine, a thread cutting process is performed on the upper side of the needle plate. Is required.
However, if the thread cutting process is performed on the upper surface side of the needle plate, the end of the needle thread at the beginning of sewing remains on the upper surface side of the sewing product for a long time, which impairs the beauty of sewing. For this reason, the long needle thread has to be cut short with scissors, and there is a problem that the working time is greatly increased.

  Therefore, the present invention has been made to solve such a problem, and the sewing thread can be trimmed automatically on the upper surface side of the needle plate in a short and automatic manner, so that the sewing finish with a good appearance can be achieved. It is an object of the present invention to provide a thread cutting method and apparatus for a single-ring stitching machine that can be obtained and that can significantly reduce the time for sewing work.

The thread cutting method of the single-ring stitch sewing machine according to the present invention will be described with reference to the reference numerals attached to FIGS. 1 to 27 in order to facilitate understanding of the contents of the invention. The sewing needle (3) passing through the workpiece (W) on the needle plate (2) through the thread (4) passing through the needle (4), and the thread of the sewing needle (3) below the needle plate (2) (1) In a single-ring stitch sewing machine having a looper (5) for handling (4) and forming a seam with one thread (4) by a sewing needle (3) and looper (5) The portion (4b) is sandwiched between the first fixed knife (12) and cut by the operation of the first movable knife (11) arranged on the upper surface side of the needle plate (2), and the upper surface of the needle plate (2) at the start of sewing. Is held between the first movable knife (11) by the spring pressure of the thread holding leaf spring (10) arranged on the side and remains on the upper surface of the sewing product (W). The end (4a) of the thread at the start of sewing is arranged on the upper surface side of the needle plate (2) and below the first fixed knife (12) at the second stitch or the second stitch after the start of sewing. The second fixed knife (13) is brought into contact with and cut at a position close to the upper surface of the workpiece (W).
According to the thread cutting method having such a configuration, the thread end (4b) at the end of sewing and the thread end (4a) at the start of sewing are cut on the upper surface side of the needle plate (2). A thread wiping mechanism (wiper device) that cuts the sewing thread after the end of sewing and lifts the cut thread end to the upper surface side of the throat plate with the wiper member is made unnecessary.
In particular, the end (4a) of the thread at the start of sewing can be automatically trimmed and short-cut.

The thread cutting device for a single ring sewing machine according to the present invention will be described with reference to the reference numerals attached to FIGS. 1 to 27 for easy understanding of the contents of the invention. The sewing needle (3) passing through the workpiece (W) on the needle plate (2) through the thread (4) passing through the needle (4), and the thread of the sewing needle (3) below the needle plate (2) A single-ring stitch sewing machine (W), which has a looper (5) for handling (4) and forms a seam with one thread (4) by the sewing needle (3) and the looper (5). ), A first fixed knife (12), a first movable knife (11), and a thread holding leaf spring (10) are arranged in this order from the bottom to the top, and the thread end (4b) at the end of sewing Thread end cutting means at the end of sewing, which is inserted into the first fixed knife (12) by the operation of the first movable knife (11) and cut, and the thread end cutting means. Thread holding means for holding the thread end (4a) at the beginning of sewing left on the sewing needle side by cutting with the first movable knife (11) by the spring pressure of the thread holding leaf spring (10); A second fixed knife (13) is arranged between the first fixed knife (12) and the upper surface of the workpiece (W), and is held by the thread holding means at the beginning of sewing and remains on the upper surface side of the workpiece (W). The thread end (4a) at the start of sewing is cut at a position close to the upper surface of the workpiece (W) by contacting the second fixed knife (13) with the second stitch or the second and subsequent stitches from the start of sewing. And a thread end cutting means at the beginning of sewing.
According to such a configuration, the cutting operation of the thread end portion at the end of sewing and the thread end portion at the start of sewing can be stably and reliably performed on the upper surface side of the needle plate. By performing such thread cutting on the upper surface side of the needle plate, even when the single ring sewing machine is a corrugated cardboard sewing machine having an elongated cylinder-shaped sewing bed, the thread end cutting means at the end of sewing and the thread holding means , And a thread cutting device including a thread end cutting means at the beginning of sewing can be easily incorporated, and a conventional sewing thread is cut after the end of sewing, and the cut thread end is wiped with a wiper member on the upper surface of the needle plate. No need for a thread wiper mechanism (wiper device) for lifting to the side.

  The thread cutting device for a single-ring stitch sewing machine according to claim 2 comprises a first fixed knife (12), a first movable knife (11), a thread holding leaf spring (10), and The second fixed knife (13) is arranged on the thread cutting base (9), and the thread cutting base bracket (14) is integrally coupled to the thread cutting base (9), and the thread cutting base (9) A thread cutting and sewing object presser unit (8) is formed by integrally connecting a sewing material presser plate (15) to the lower surface, and the thread cutting base bracket (14) is attached to a presser bar (7 The structure attached to the lower end of) so that attachment or detachment is possible is employable. According to this, since the thread cutting / sewing material presser unit (8) can be easily attached to and detached from the single ring sewing machine on the upper side of the needle plate (2), the first movable knife (11), the first fixed Maintenance such as replacement of the knife (12) and the second fixed knife (13) is easy.

  According to a third aspect of the present invention, there is provided a thread cutting device for a single-ring stitch sewing machine, wherein, as described in the fourth aspect, the thread cutting / sewing material presser unit (8) starts sewing at the second stitch after the second stitch or after the second stitch. A yarn wiping air nozzle (34) for removing the remaining yarn generated by cutting the yarn and held between the yarn holding leaf spring (10) and the first movable knife (11) is integrally attached. .

  According to the thread cutting method and apparatus of a single-ring stitching machine of the present invention, the thread end portion at the start of sewing can be automatically and shortly trimmed on the upper surface side of the needle plate, so that the sewing can be finished beautifully, In addition, the sewing work time can be greatly shortened.

  Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing a single ring sewing machine according to an embodiment of the present invention with a thread cutting / sewing presser unit removed, and FIG. 2 is a thread cutting / sewing presser unit of the single ring sewing machine. 3 is a front view of the single-ring stitch sewing machine of FIG. 2, FIG. 4 is a cross-sectional view taken along line AA in FIG. 3, and FIG. 5 is a cross-sectional view taken along line BB in FIG. is there.

  In these figures, a single-ring stitch sewing machine 1 according to an embodiment of the present invention has a needle plate provided on a sewing machine bed 1B by passing a thread 4 (see FIG. 20) through a needle tip and moving up and down at the tip of a sewing machine arm 1A. The sewing needle 3 passing through the workpiece (cardboard or cloth, etc.) W placed on the needle 2, the thread 4 of the sewing needle 3 under the needle plate 2, and the sewing needle 3 in cooperation with the sewing needle 3. Looper 5 (see FIG. 20B) that forms a seam with thread 4, presser bar 7 provided in the vicinity of needle bar 6, thread cutting / sewing product presser unit 8 that is detachably attached to presser bar 7, etc. It has. The single-ring sewing machine 1 in the illustrated example is a cardboard sewing machine in which a seam is sewn to a stitched portion of a cardboard box.

  6 to 12 show the thread cutting / sewing product presser unit 8, and FIG. 18 shows an exploded perspective view of the thread cutting / sewing product presser unit 8. In these figures, the thread cutting / sewing product presser unit 8 is shown. The presser unit 8 has a second fixed knife 13, a first fixed knife 12, a first movable knife 11, and a thread holding leaf spring 10 arranged in order from the lower side to the upper side on the thread cutting base 9. The thread cutting base bracket 14 is integrally coupled to the thread cutting base 9, and the sewing material presser plate 15 for pressing the sewing product W against the lower surface of the thread cutting base 9 is set with a set screw 27 (see FIGS. 7 and 12). Etc. are integrally coupled with each other. The thread holding leaf spring 10, the first movable knife 11, the first fixed knife 12, and the second fixed knife 13 are respectively provided in pairs on the left and right sides to correspond to the two sewing needles 3 (two-row single ring sewing). Yes.

  More specifically, as shown in FIGS. 6 to 11 and 18, the first fixing knife 12 is fixed on the thread cutting base 2 with a screw 16. The first movable knife 11 is attached to the thread cutting base 9 so as to be reciprocally rotatable around the pin 18 by driving an air cylinder 17 for driving the movable knife. The air cylinder 17 is attached to the thread cutting base bracket 14. The air cylinder 17 has a rod end bracket 20 coupled to an end of a rod 19, a first rod end 21 is coupled to the rod end bracket 20 with a bolt 22, and a second rod end 23 is screwed into the first rod end 21. The left movable female lever 24 is coupled to the second rod end 23 with a bolt 25. The left first movable knife 11 is connected to the left movable knife lever 24 via the left movable knife bracket 26 and the pin 18. The right first movable knife 11 is connected to the right movable knife lever 30 via the right movable knife bracket 28 and the pin 18, and the right movable knife lever 30 is coupled to the right end of the movable knife link 31 with a screw 32. The left end of the link 31 is coupled to the left movable knife lever 24 with a screw 33.

When the rod end bracket 20 of the air cylinder 17 moves forward as shown in FIG. 10 from the original position in FIGS. 16 and 17, the left first movable knife 11 is moved to the first and second rod ends 21 and 23 and It rotates clockwise around the pin 18 via the left movable knife lever 24 and moves away from the left first fixed knife 12 to the forward end position. At the same time, the right first movable knife 11 moves to the movable knife link 31. Then, it rotates counterclockwise around the pin 18 via the right movable knife lever 30 and moves away from the right first fixed knife 12 to the forward end position.
When the rod end bracket 20 of the air cylinder 17 moves backward from the forward movement end position state of FIG. 10 as shown in FIGS. 16 and 17, the left first movable knife 11 has the first and second rod ends 21 and 23 and the left It rotates counterclockwise around the pin 18 via the movable knife lever 24 and engages with the left first fixed knife 12. At the same time, the right first movable knife 11 passes through the movable knife link 31 and the right movable knife lever 30. The right and left sewing needle threads are cut by rotating clockwise around the pin 18 and meshing with the right first fixed knife 12.

  Further, as shown in FIGS. 6, 7, and 18, the thread cutting / sewing product presser unit 8 has a thread cutting air nozzle 34 attached to the thread cutting base bracket 14 with a nozzle mounting guide 35 and a nozzle mounting bracket 36. Become.

To attach the thread cutting / sewing material presser unit 8 to the single-ring sewing machine 1, insert the hole 37 of the thread cutting base bracket 14 into the lower end of the presser bar 7, as shown in FIGS. The bolt 38 is fastened and fixed, and the anti-rotation member 39a is engaged with the anti-rotation bar 39b on the single-ring sewing machine 1 side and attached in the anti-rotation state. By this attachment, the second fixed knife 13, the first fixed knife 12, the first movable knife 11, and the thread holding leaf spring are arranged in this order from the lower side to the upper side on the workpiece W placed on the needle plate 2. 10 will be arranged. The first movable knife 11 and the first fixed knife 12 constitute a thread end cutting means at the sewing end that sandwiches and cuts the thread end portion at the sewing end. The thread holding leaf spring 10 and the first movable knife 11 constitute a thread end holding means at the start of sewing that holds the thread end portion of the sewing start that is cut by the thread end cutting means at the end of sewing and remains on the sewing needle side. . The sewing product presser plate 15 constitutes a sewing product presser for pressing the sewing product W from above so that the sewing product W placed on the needle plate 2 is not displaced.
The second fixed knife 13 is disposed between the first fixed knife 12 and the upper surface of the workpiece W. The second fixed knife 13 is held between the thread holding leaf spring 10 and the first movable knife 11 at the beginning of sewing, and the end of the sewing start thread left on the upper surface side of the sewing product W is started from the start of sewing. A thread end cutting means at the start of sewing is configured to cut at the second stitch or the stitch after the second stitch.
In order to remove the thread cutting / sewing material presser unit 8 from the single ring sewing machine 1, the bolt 38 is removed from the thread cutting base bracket 14, and the hole 37 of the thread cutting base bracket 14 is pulled out from the lower end of the presser bar 7.

  FIG. 19 is a flowchart showing the thread trimming operation process, and FIGS. 20 to 27 show each operation diagram based on the flowchart of FIG. Next, the thread trimming operation will be described with reference to FIGS. 19 and 20 to 27.

  FIG. 20 shows the time when the thread trimming operation starts after the end of sewing (the sewing needle 3 stops at the top dead center position), and P is the thread at the start of sewing in the middle of the second stitch in the previous sewing as will be described later. The remaining yarn generated by cutting the end portion 4a (see FIG. 26) is shown, and this remaining yarn P is held between the first movable knife 11 by the spring pressure of the yarn holding leaf spring 10.

  As shown in FIG. 21, the remaining thread P is separated from the thread holding leaf spring 10 when the first movable knife 11 rotates around the pin 18 in the direction away from the first fixed knife 12, and the remaining thread P The nozzle 34 blows away.

  Next, the thread end 4b at the end of sewing is rotated in a direction in which the first movable knife 11 separated from the first fixed knife 12 approaches the first fixed knife 12 around the pin 18 as shown in FIG. Then, it is cut by engaging with the first fixed knife 12. At this time, the thread end portion 4 a at the start of sewing remaining on the sewing needle side is held between the first movable knife 11 by the spring pressure of the thread holding leaf spring 10.

  After cutting the thread end 4b at the end of sewing, the workpiece (workpiece) W is discharged in the direction of arrow X as shown in FIG. At this time, since the thread end 4b at the sewing end on the looper 5 side is hooked on the looper 5, the thread end 4b comes out from the looper 5 along with the discharge of the workpiece W, and then comes out to the lower surface side (back side) of the workpiece W. Come. If the thread 4b at the end of sewing protrudes from the lower surface side of the sewing object W, it is difficult to unwind because there is little contact with other objects. The thread end 4a on the sewing needle side is held between the first movable knife 11 by the spring pressure of the thread holding leaf spring 10 as described above. The length of the thread end 4b at the end of sewing varies depending on the thickness of the workpiece W.

  Next, sewing of a new sewing product W is started as shown in FIG. FIG. 25 shows the state of the first stitch at the start of sewing of the new workpiece W. At this time, the thread end 4a at the sewing start on the sewing needle side is the spring of the thread holding leaf spring 10 as described above. Since the first movable knife 11 is held by the pressure, the first stitch of the workpiece W is reliably formed.

  FIG. 26 shows a state in the middle of the second stitch. In the middle of the second stitch as shown in FIG. 26, the thread end 4a at the start of sewing held between the thread holding leaf spring 10 and the first movable knife 11 feeds the workpiece W in the arrow Y direction. Accordingly, the angle comes into contact with the second fixed knife 13 while being applied with tension, and the contact is automatically cut at a position close to the upper surface of the workpiece W. As a result, the thread end portion 4c at the start of sewing remaining on the upper surface side of the workpiece W is shortened, and the appearance of the sewing product is improved.

  FIG. 27 shows a state in the middle of sewing after the second stitch. The remaining thread P that has been cut in the process shown in FIG. 26 and held between the thread holding leaf spring 10 and the first movable knife 11 remains as it is during sewing, and the remaining thread skipping process in FIG. It blows away so that it may not adhere to the to-be-sewn material W with the air nozzle 34 for payment.

  In the above embodiment, the thread end 4a at the start of sewing which is held at the beginning of the sewing and remains on the upper surface side of the sewing product W is brought into contact with the second fixed knife 13 at the second stitch from the start of sewing to Cut at a position close to the upper surface, but instead of this, the thread end portion 4a at the beginning of sewing that is held at the beginning of the sewing and remains on the upper surface side of the sewing product W is replaced with a predetermined stitch of, for example, the third to fifth stitches. Then, the second fixed knife 13 may be contacted and cut at a position close to the upper surface of the workpiece W.

  In the above-described embodiment, the first movable knife 11, the first movable knife 11, the first movable knife 11, the first movable knife 11, A fixed knife 12, a thread holding leaf spring 10 and a second fixed knife 13 are provided on a thread cutting base 9, and a thread cutting base bracket 14 is integrally coupled to the thread cutting base 9. A thread cutting / sewing object presser unit 8 is formed by integrally connecting a sewing object presser plate 15 to the lower surface of the sewing machine. However, the present invention is not limited to this, and the first movable knife 11, the first fixed knife 12, and the thread holding unit are not limited thereto. The thread cutting device including the plate spring 10 and the second fixed knife 13 and the workpiece presser plate 15 may be separately and independently installed on the needle plate 2 of the single-ring sewing machine 1. .

  Further, the first movable knife 11 is moved away from the first fixed knife 12 by linear movement instead of being moved away from and approaching the first fixed knife 12 by rotating around the pin as in the above embodiment. -It can also be approached. The remaining yarn P can be sucked with a remaining yarn suction hose or the like instead of blowing away with the yarn wiper air nozzle 34.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external perspective view showing a single-ring stitch sewing machine according to an embodiment of the present invention with a thread cutting / sewing material presser unit removed. FIG. 2 is an external perspective view showing the single ring sewing machine with a thread cutting / sewing material presser unit attached thereto. FIG. 3 is a front view of the single ring sewing machine of FIG. 2. It is the sectional view on the AA line in FIG. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is the external appearance perspective view which looked at the thread cutting and to-be-sewn material presser unit from above. It is the external appearance perspective view which looked at the thread cutting and to-be-sewn material presser unit from the bottom side. It is a front view of a thread cutting and sewing product presser unit. It is a top view of a thread | yarn cutting and to-be-sewn material presser unit. It is CC sectional view taken on the line in FIG. It is the DD sectional view taken on the line in FIG. It is the EE sectional view taken on the line in FIG. FIG. 7 is an external perspective view showing the operating state of the first movable knife of the thread cutting / sewing material presser unit corresponding to FIG. 6. FIG. 9 is a front view showing the operating state of the first movable knife of the thread cutting / sewing material presser unit corresponding to FIG. 8. FIG. 10 is a plan view corresponding to FIG. 9 showing an operating state of the first movable knife of the thread cutting / sewing material presser unit. It is the FF sectional view taken on the line in FIG. It is the GG sectional view taken on the line in FIG. It is a disassembled perspective view of a thread cutting / sewing material presser unit. It is a flowchart which shows a thread trimming operation process. FIG. 2A shows an external perspective view, FIG. 2B is a vertical front view of a seam portion, and FIG. 2C is a vertical perspective view of a seam portion when a thread trimming operation starts after the end of sewing. FIG. 4A is an external perspective view, FIG. 4B is a longitudinal front view of a seam portion, and FIG. 4C is a longitudinal perspective view of a seam portion. FIG. 5 is a diagram illustrating a thread trimming start operation after the end of sewing, in which (a) is an external perspective view, (b) is a longitudinal front view of a seam portion, and (c) is a vertical perspective view of a seam portion. FIG. 4A is a perspective view of an appearance, FIG. 2B is a vertical front view of a seam portion, and FIG. 3C is a vertical perspective view of a seam portion. The sewing operation is started, (a) is an external perspective view, (b) is a longitudinal front view of a seam portion, and (c) is a vertical perspective view of a seam portion. The operation | movement diagram of the 1st stitch | needle is shown, (a) is an external appearance perspective view, (b) is a vertical front view of a seam part, (c) is a vertical perspective view of a seam part. The cutting | disconnection operation | movement figure of the sewing start thread | yarn in the middle of the 2nd stitch is shown, (a) is an external perspective view, (b) is a longitudinal front view of the seam portion, and (c) is a longitudinal perspective view of the seam portion. The operation | movement figure in the middle of the sewing after the 2nd stitch is shown, (a) is an external perspective view, (b) is a longitudinal front view of the seam portion, and (c) is a longitudinal perspective view of the seam portion.

Explanation of symbols

1 Single-ring sewing machine 2 Needle plate 3 Sewing machine needle 4 Thread 4a Thread end at the start of sewing
4b Thread end portion at sewing end 5 Looper 7 Presser bar 8 Thread cutting / sewing material presser unit 9 Thread cutting base 10 Thread holding leaf spring 11 First movable knife 12 First fixed knife 13 Second fixed knife 14 Thread cutting base Bracket 15 Sewing material presser plate 34 Thread wiper air nozzle

Claims (4)

  A sewing needle that passes through the workpiece on the needle plate by moving the thread through the needle tip and moves up and down, and a looper that handles the thread of the sewing needle below the needle plate, one by the sewing needle and the looper In a single-ring stitch sewing machine in which a seam is formed with a thread, the end of the thread at the end of sewing is cut by being sandwiched between the first fixed knife by the operation of the first movable knife arranged on the upper surface side of the needle plate, and then sewn. First, an end portion of a thread at the start of sewing which is held between the first movable knife and left on the upper surface side of the sewing object by a spring pressure of a thread holding leaf spring disposed on the upper surface side of the needle plate. Is the second stitch from the start of sewing, or the second and subsequent stitches, and is brought into contact with the second fixed knife located on the upper surface side of the needle plate and below the first fixed knife, so as to contact the upper surface of the workpiece. A thread cutting method for a single-ring stitch sewing machine, characterized by cutting at a close position.   A sewing needle that passes through the workpiece on the needle plate by moving the thread through the needle tip and moves up and down, and a looper that handles the thread of the sewing needle below the needle plate, one by the sewing needle and the looper In the single-ring stitch sewing machine that forms the seam with the thread, a first fixed knife, a first movable knife, and a thread holding leaf spring are arranged on the upper side of the sewing product in order from the lower side to the upper side. Thread end cutting means at the sewing end for cutting the thread end portion at the end of sewing by inserting the first movable knife into the first fixed knife, and the sewing left on the sewing machine needle side by the cutting by the thread end cutting means Thread holding means for holding the first yarn end portion between the first movable knife and the first movable knife by the spring pressure of the thread holding leaf spring, and a second fixed between the first fixed knife and the upper surface of the sewing product. An upper surface of the sewing product that is held by the thread holding means at the beginning of sewing is arranged The thread end at the start of sewing is cut at a position close to the top surface of the sewing product by contacting the second thread from the start of sewing with the second stitch after the first stitch, or the second and subsequent stitches. And a thread cutting device for a single-ring stitch sewing machine.   The first fixed knife, the first movable knife, the thread holding leaf spring, and the second fixed knife are arranged on a thread cutting base, and a thread cutting base bracket is integrally coupled to the thread cutting base. A thread cutting / sewing material presser unit is formed by integrally connecting a sewing material presser plate to the lower surface of the thread cutting base, and the thread cutting base bracket is attached to and detached from the lower end of the presser bar of the single-ring sewing machine. The thread cutting device for a single-ring stitch machine according to claim 2, wherein the thread-cutting device is attached in a possible manner.   The remaining thread held between the thread holding leaf spring and the first movable knife is generated by cutting the sewing start thread at the second stitch of the previous sewing or after the second stitch in the thread cutting / workpiece presser unit. 4. The thread cutting device for a single-ring stitch machine according to claim 3, wherein a thread-wiping air nozzle is attached integrally.

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