Chain stitch sewing machine and sewing method using the same

Abstract

The present invention provides a needle for a cover chain stitch sewing machine and a sewing method using the same, which can reduce the difference in size of loops formed by a plurality of needles as much as possible. A surface groove (23) of a needle (10) for a cover chain stitch sewing machine has a step portion (23a) at a position on the shank portion (11) side than the notch portion (24), and the surface groove (23) is formed in such a manner that the depth of the groove becomes deeper as it goes from the needle tip (21) side toward the shank portion (11). That is, a shallow groove portion (23b) is formed at a position on the needle tip (21) side than the step portion (23a), and a deep groove portion (23c) is formed at a position on the shank portion (11) side than the step portion (23a).

Description

Technical Field

[0001] This invention relates to needles used in covered chain stitch sewing machines and sewing methods using covered chain stitch sewing machines. Background Technology

[0002] For example, as described in Patent Document 1, in a covered chain stitch sewing machine, multiple (2 to 4) needles are arranged and installed at varying heights in a direction orthogonal to the fabric feeding direction. Then, by moving these multiple needles up and down to form multiple loops under the fabric, sewing is performed by hooking these multiple loops with a looper.

[0003] Furthermore, the loops on the underside of the fabric are formed by the following action: First, the needle descends to its bottom stop position, pulling the thread passing through the needle eye downwards into the fabric, thus tautning it. As the needle moves upwards from this position, the thread is pressed down due to friction with the fabric, causing the thread on the underside of the fabric to loosen and form loops. Because multiple needles move up and down simultaneously, loops corresponding to the number of needles can be formed.

[0004] Multiple loops formed beneath the fabric are sequentially caught by a single looper, resulting in different entry times for each loop. Since the looper catches the loops sequentially as the needle rises from its bottom stop position, the distance the needle travels from the bottom stop position varies depending on the entry time. Even with these differences in needle travel distance, the needle height must be consistent at the entry time (the height of the notch must match the height of the looper). Therefore, multiple needles are mounted on the sewing machine's needle bar at varying heights.

[0005] Specifically, the needle that the looper first hooks into is installed at the highest position. Conversely, the needle that the looper last hooks into is installed at the lowest position. By installing the needles in this way, although the time when the needle meets the looper (i.e., the amount of rise of the needle from the bottom dead center) is different, the height of the needle when it meets the looper is set to be approximately the same for all needles.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2012-45134 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] However, the first needle hooked by the looper will meet the looper relatively early after the needle begins to rise, thus the amount of rise the needle makes to form a loop (the amount of rise the needle makes from the bottom dead center position to when it meets the looper) is smaller. Therefore, it may not be possible to form a sufficient loop, resulting in skipped stitches because the looper cannot hook the loop.

[0011] Conversely, the last needle hooked by the looper will meet the looper at a later time after the needle begins to rise, resulting in a larger rise for the needle to form the loop. Therefore, the loop may become too large and tip over, making it impossible to hook the loop with the looper and causing skipped stitches.

[0012] Therefore, the objective of this invention is to provide a cover chain stitch sewing machine needle and a sewing method that can minimize the size difference of loops formed by multiple needles in a cover chain stitch sewing machine.

[0013] Solution for solving the problem

[0014] To solve the above problems, the first technical solution is a covered chain stitch sewing machine needle used in a covered chain stitch sewing machine, in which multiple needles arranged at varying heights in a direction orthogonal to the fabric feed direction are moved up and down to form multiple loops under the fabric, and a looper is used to hook these multiple loops to perform sewing. The covered chain stitch sewing machine needle includes: a shank that is held when mounted on the sewing machine; and a needle body that has a thread hole formed at its tip and is inserted and withdrawn relative to the fabric. A surface groove is formed on the needle body extending from the opening edge of the thread hole toward the shank, and a notch is formed on the back side of the surface groove that recesses the outline of the needle body. The surface groove has a stepped portion at a position closer to the shank than the notch, and the surface groove is formed in the stepped portion such that the depth of the groove increases as it moves from the needle tip toward the shank.

[0015] Alternatively, the second technical solution is a sewing method using a covered chain stitch sewing machine. In this machine, multiple covered chain stitch sewing machine needles, arranged at varying heights in a direction orthogonal to the fabric feeding direction, are moved up and down to form multiple loops under the fabric. A looper is used to hook these loops to perform sewing. The covered chain stitch sewing machine needle includes: a shank that is held in place when mounted on the sewing machine; and a needle body with a thread hole at its tip that is inserted and withdrawn relative to the fabric. A surface groove extending from the opening edge of the thread hole toward the shank is formed on the needle body, and a notch in the shape of a recessed profile of the needle body is formed on the back side of the surface groove. The surface groove has a stepped portion closer to the shank than the notch, and the depth of the groove in the stepped portion increases as it moves from the needle tip toward the shank.

[0016] The effects of the invention

[0017] As described above, the present invention provides a surface groove for a needle used in a chain stitch sewing machine. The groove has a stepped portion on the shank side, closer to the notch. The groove depth increases as it moves from the needle tip towards the shank. Specifically, a shallow groove is formed on the needle tip side, and a deep groove is formed on the shank side. When the portion of the needle body with the shallow groove is pulled out of the fabric, the resistance between the shallow groove and the fabric's thread is greater, thus the thread is pressed down and the loop easily forms. Conversely, when the portion of the needle body with the deep groove is pulled out of the fabric, the resistance between the deep groove and the fabric's thread is less, thus the loop does not easily form.

[0018] Here, the first needle hooked by the looper is installed at the highest position, so even when moved to the bottom stop position, it is inserted relatively shallowly into the fabric. Since the loop is formed by rising from this position, the loop is formed using the shallow groove on the needle tip side. Therefore, even if the amount of needle rise for loop formation (the amount of needle rise from the bottom stop position to when it meets the looper) is small, the shallow groove can be used to allow the loop to grow sufficiently large.

[0019] Furthermore, since the last hook of the looper is installed at its lowest position, it penetrates the fabric quite deeply when it reaches the bottom stop position. Because the loop is formed from this position, it is formed using the deep groove on the shank side and the shallow groove on the needle tip side. Therefore, even if the needle's rise for loop formation (the rise from the bottom stop position to when it meets the looper) is large, the loop will not grow excessively as it passes through the fabric in the deep groove, and it can grow larger as it passes through the fabric in the shallow groove. In other words, the deep groove can suppress loop growth, thus preventing the loop from becoming too large.

[0020] In this way, if the covered chain stitch sewing machine needle of the present invention is used, the difference in the size of the loop when it meets the looper can be reduced even when the needle is mounted at different heights. By making the loop size as consistent as possible, skipped stitches can be prevented. Attached Figure Description

[0021] Figure 1 (a) is a front view of a needle covering a chain stitch sewing machine. Figure 1 (b) is a side view covering the needle of a chain stitch sewing machine. Figure 1 (c) is a rear view of the needle used in a chain stitch sewing machine.

[0022] Figure 2 (a) is along Figure 1 The cross-sectional view of line AA shown in (a) Figure 2 (b) is along Figure 1 A partial enlarged view of the cross section of line AA shown in (a).

[0023] Figure 3 This diagram illustrates the movement of the needle in a covered chain stitch sewing machine during sewing. Figure 3 (a) is a diagram showing the position of the bottom stop of the needle on a chain stitch sewing machine. Figure 3 (b) is a diagram showing the position of the needle on a chain stitch sewing machine at the moment when the right needle and the looper meet. Figure 3 (c) is a diagram showing the position of the needle on a chain stitch sewing machine at the moment when the left needle and the looper meet.

[0024] Explanation of reference numerals in the attached figures

[0025] 10. Needle for a chain stitch sewing machine; 11. Shank; 20. Needle body; 21. Needle tip; 22. Thread hole; 23. Surface groove; 23a. Stepped section; 23b. Shallow groove; 23c. Deep groove; 23e. Inclined section; 24. Notch; 25. Back groove; 30. Needle bar; 31. Needle fixing section; 32. Needle plate; 35. Fabric; N1. Right needle; N2. Middle needle; N3. Left needle; P1a. Right needle at the bottom stop position on the upper surface of the fabric; P1b 1. The position of the right needle on the lower surface of the fabric when it meets the looper; P3a. The position of the left needle on the upper surface of the fabric at the bottom stop; P3b. The position of the left needle on the lower surface of the fabric when it meets the looper; S1. The loop formation area of ​​the right needle; S3. The loop formation area of ​​the left needle; H. The length of the needle body; M. The middle position of the needle body in the length direction; C. The center line of the needle; D1. The bottom surface of the shallow groove; D2. The bottom surface of the deep groove; K. The distance from the center line of the needle to the bottom surface of the shallow groove. Detailed Implementation

[0026] Embodiments of the present invention will be described with reference to the accompanying drawings.

[0027] The cover chain stitch sewing machine needle 10 of this embodiment is a needle used in a cover chain stitch sewing machine. Cover chain stitch sewing machines are conventionally known, so detailed descriptions are omitted. Multiple cover chain stitch sewing machine needles 10, arranged at varying heights in a direction orthogonal to the fabric feed direction, are moved up and down to form multiple loops under the fabric. A looper is used to hook these multiple loops to perform sewing. For the cover chain stitch sewing machine needle 10 of this embodiment, multiple identical needles are installed and used in such a cover chain stitch sewing machine.

[0028] like Figure 1 As shown, the needle 10 for a chain stitch sewing machine includes: a shank 11, which is held when mounted on the sewing machine; and a needle body 20, which is located at a position closer to the top of the shank 11.

[0029] like Figure 3 As shown, the handle 11 is held and mounted on the needle fixing part 31 of the sewing machine. Furthermore, the needle fixing part 31 is located at the top end of the needle bar 30, which moves up and down during sewing. The sewing machine of this embodiment uses three covered chain stitch sewing machine needles 10; therefore, three covered chain stitch sewing machine needles 10 are mounted on the needle fixing part 31. Figure 3 As shown, the needle tips 21 of the three covered chain stitch sewing machine needles 10 are installed in a manner that gradually increases in height as viewed from left to right, and are arranged in a direction orthogonal to the feed direction. Furthermore, this embodiment describes a sewing machine using three covered chain stitch sewing machine needles 10, but the number of needles is not limited to three; it can be two or more. Additionally, in this embodiment, when viewed from the front side (downstream side of the feed direction), the needles are installed in a manner that gradually increases in height as viewed from left to right, but this is not a limitation; the needles can also be installed in a manner that gradually increases in height as viewed from right to left.

[0030] The needle body 20 is the part that penetrates the fabric 35 and is inserted or removed relative to the fabric during sewing. The tip of the needle body 20 is sharp, forming a needle tip 21. A thread hole 22 is formed near the tip of the needle body 20 for the top thread to pass through. In addition, the needle tip 21 does not necessarily need to be sharp; for example, it can be spherical.

[0031] like Figure 1 As shown in (a), a surface groove 23 is formed on the surface side of the needle body 20, extending from the opening edge of the thread hole 22 toward the shank 11. This surface groove 23 is a groove for guiding the thread through the thread hole 22, and is provided extending in the length direction of the needle body 20.

[0032] In addition, such as Figure 1 (b) and Figure 1 As shown in (c), a notch 24 is formed on the back side of the needle body 20 (the side opposite to the surface where the surface groove 23 is formed), at a position closer to the shank 11 than the wire hole 22. The notch 24 is shaped to recess the outline of the needle body 20. In addition, the notch 24 is provided close to the wire hole 22 (in this embodiment, it is formed such that the distance between the notch 24 and the wire hole 22 is shorter than the width of the wire hole 22 in the longitudinal direction).

[0033] Furthermore, a back groove 25 is formed at a position closer to the shank 11 than the notch 24. This back groove 25 is a groove for guiding the thread through the thread hole 22 and extends along the length of the needle body 20.

[0034] Furthermore, the aforementioned surface groove 23 is formed such that its depth varies along its length. Specifically, as... Figure 2 As shown, the surface groove 23 has a stepped portion 23a, and the depth of the groove in the stepped portion 23a increases as it moves from the needle tip 21 towards the shank 11. This stepped portion 23a is located on the shank 11 side closer to the notch 24. Figure 2 The step portion 23a is located on the upper side of the needle body 20. Furthermore, the step portion 23a is located on the side of the handle portion 11, which is closer to the position where the length H of the needle body 20 is bisected (the middle position M in the length direction of the needle body 20).

[0035] Furthermore, the depth of the groove in this embodiment is determined from the center line C of the needle (refer to...). Figure 2 The distance from the needle's center line C to the bottom of the groove is specified. That is, regardless of the needle's outline shape, the depth of the groove is specified based on the needle's center line C. Therefore, a "deeper groove" means that the distance from the needle's center line C to the bottom of the groove is shorter, and a "shallower groove" means that the distance from the needle's center line C to the bottom of the groove is longer.

[0036] like Figure 2 As shown in (b), the bottom surface of the stepped portion 23a is formed such that the groove gradually deepens as it moves from the needle tip 21 towards the handle 11. The bottom surface of the stepped portion 23a is slightly curved, forming a convex surface that bulges out in the direction where the groove deepens. Furthermore, the shape of the stepped portion 23a is not limited to such a curved surface; it can also be a curved surface that bulges out in the direction where the groove becomes shallower, or it can be a flat surface.

[0037] The portion of the surface groove 23 closer to the needle tip 21 than the stepped portion 23a becomes a shallow groove portion 23b, which is shallower than the groove itself. In other words, the stepped portion 23a is continuously formed on the handle portion 11 side of the shallow groove portion 23b. The depth of this shallow groove portion 23b is constant. Specifically, as... Figure 2As shown in (b), the distance K from the center line C of the needle to the bottom surface D1 of the shallow groove 23b is formed to be constant over the entire length of the shallow groove 23b.

[0038] The portion of the surface groove 23 closer to the handle 11 than the stepped portion 23a becomes a deep groove 23c, which is deeper than the shallow groove 23b. In other words, the stepped portion 23a is continuously formed on the tip 21 side of the deep groove 23c. The depth of the deep groove 23c is constant. Specifically, as... Figure 2 As shown in (b), the distance from the center line C of the needle to the bottom surface D2 of the groove 23c is formed to be constant over the entire length of the groove 23c. Furthermore, in this embodiment, the bottom surface D2 of the groove 23c is formed to pass through the center line C of the needle.

[0039] The portion of the surface groove 23 closer to the handle 11 than the deep groove 23c becomes an inclined portion 23e that gradually becomes shallower as it moves toward the handle 11. In other words, the inclined portion 23e is continuously formed on the handle 11 side of the deep groove 23c.

[0040] In this embodiment, the surface groove 23 is formed such that its depth varies at the step portion 23a. Furthermore, even though the depth varies at the step portion 23a, the width of the surface groove 23 remains constant. That is, the width of the surface groove 23 is constant across the shallow groove portion 23b, the step portion 23a, and the deep groove portion 23c.

[0041] like Figure 3 As shown in (a), the step portion 23a that causes the depth of the surface groove 23 to change is formed in the following position: when multiple cover chain stitch sewing machine needles 10 are installed in the cover chain stitch sewing machine and moved to the lower stop point, the cover chain stitch sewing machine needle 10 installed at the highest position among the multiple cover chain stitch sewing machine needles 10 ( Figure 3 (a) The right needle N1) in the step portion does not penetrate the fabric 35 placed on the needle plate 32, and the covered chain stitch sewing machine needle 10 installed in the lowest position among the multiple covered chain stitch sewing machine needles 10 ( Figure 3 The stepped portion of the left needle N3 (a) penetrates the fabric 35 placed on the needle plate 32. In other words, the right needle N1, which is the highest-positioned cover chain stitch sewing machine needle 10, is configured such that its stepped portion 23a is not located below the fabric 35 when it is moved to the bottom stop position. Furthermore, the left needle N3, which is the lowest-positioned cover chain stitch sewing machine needle 10, is configured such that its stepped portion 23a is located below the fabric 35 when it is moved to the bottom stop position.

[0042] Next, the moment when the needle 10 of the covered chain stitch sewing machine meets the curved needle (not shown) of the sewing machine will be explained.

[0043] In this embodiment, three cover chain stitch sewing machine needles 10 are installed on the needle bar 30 (needle fixing part 31) of the sewing machine. The three cover chain stitch sewing machine needles 10 are arranged with varying heights in a direction orthogonal to the fabric feeding direction. The needle installed at the highest position among these three cover chain stitch sewing machine needles 10 is called the right needle N1, the needle installed at the lowest position is called the left needle N3, and the needle installed at a height between the right needle N1 and the left needle N3 is called the middle needle N2. These needles... Figure 3 The needles are installed parallel to each other at equal intervals from right to left, in the order of right needle N1, middle needle N2, and left needle N3. All three needles (10) used on this chain stitch sewing machine are identical.

[0044] Below the needle bar 30 of the sewing machine is a needle plate 32 for holding the sewing object, i.e., the fabric 35. A hole is formed through the needle plate 32 for the needle 10 of the chain stitch sewing machine to pass through.

[0045] like Figure 3 As shown in (a), when sewing with the needle 10 of the covered chain stitch sewing machine of this embodiment, the needle bar 30 of the sewing machine moves to the lower stop position, pulling the top thread (not shown) passing through the thread hole 22 downwards to make it taut. At this time, the step portion 23a of the right needle N1 is not below the fabric 35. In addition, the step portion 23a of the left needle N3 is below the fabric 35. Furthermore, when the needle rises from this lower stop position, resistance is generated between the top thread and the fabric 35, thereby forming a loop. Therefore, the position of the upper surface of the fabric 35 at this lower stop position becomes the reference line for generating the resistance for forming the loop. Specifically, Figure 3 In the attached drawing (a), reference numeral P1a indicates the position of the upper surface of fabric 35 at the bottom stop of the right needle N1, and is also the starting reference position for the formation of the loop of the right needle N1. Additionally, Figure 3 The reference numeral P3a shown in (a) is the position of the upper surface of the fabric 35 at the lower stop position of the left needle N3, and is the starting reference position for the formation of the loop of the left needle N3.

[0046] As the needle moves upward from the lower stop position, the thread is pressed due to friction with the fabric 35, causing the thread to loosen below the fabric 35 and form a loop.

[0047] Then, as the needle rises to Figure 3At the position shown in (b) (when the height of the notch 24 of the right needle N1 is the same as the height of the top of the looper), the right needle N1 first crosses the looper, and the looper is used to hook the loop formed by the right needle N1. At the moment when the right needle N1 meets the looper, the loop formation is complete, therefore the position of the lower surface of the fabric 35 at this time becomes the baseline for the completion of the loop formation. Specifically, Figure 3 The reference numeral P1b shown in (b) is the position of the lower surface of the fabric 35 at the moment when the right needle N1 meets the looper, and becomes the end reference position for the loop formation of the right needle N1. Therefore, as Figure 2 As shown, the range from reference numeral P1a to reference numeral P1b is called the coil forming interval S1 of the right needle N1.

[0048] After this, as the needle rises further, the middle needle N2 crosses with the curved needle, and the curved needle is used to hook the loop formed by the middle needle N2.

[0049] Then, the needle rises further, until it reaches... Figure 3 At the position shown in (c) (when the height of the notch 24 of the left needle N3 is the same as the height of the tip of the bent needle), the left needle N3 crosses with the bent needle, and the bent needle is used to hook the loop formed by the left needle N3. Therefore, Figure 3 The reference numeral P3b shown in (c) is the position of the lower surface of the fabric 35 at the moment when the left needle N3 meets the looper, and becomes the end reference position for the loop formation of the left needle N3. Therefore, as Figure 2 As shown, the range from reference numeral P3a to reference numeral P3b is called the coil forming interval S3 of the left needle N3.

[0050] Then, the needle rises above fabric 35. This up-and-down movement of the needle is used to perform the overlock chain stitch.

[0051] Furthermore, in this embodiment, such as Figure 2 As shown, the loop-forming section S1 of the right needle N1 is entirely a shallow groove 23b. Therefore, the resistance between the top thread and the fabric 35 is relatively large during loop formation, and even the right needle N1, with its small rise until it meets the curved needle, can form a loop of sufficient size.

[0052] In addition, such as Figure 2 As shown, the loop formation section S3 of the left needle N3 includes a deep groove 23c and a shallow groove 23b. Therefore, when the deep groove 23c passes through the fabric 35, the resistance between the top thread and the fabric 35 is small, thus suppressing loop growth. Therefore, even if the left needle N3 has a large rise until it meets the curved needle, the loop will not be too large.

[0053] As explained above, in this embodiment, the surface groove 23 of the needle 10 for a chain stitch sewing machine has a stepped portion 23a at a position closer to the shank 11 than the notch portion 24. The surface groove 23 is formed at this stepped portion 23a such that the depth of the groove increases as it moves from the needle tip 21 towards the shank 11. That is, a shallow groove 23b is formed at a position closer to the needle tip 21 than the stepped portion 23a, and a deep groove 23c is formed at a position closer to the shank 11 than the stepped portion 23a. When the portion of the needle body 20 containing the shallow groove 23b is pulled out of the fabric 35, the resistance of the thread sandwiched between the shallow groove 23b and the fabric 35 is greater, and the thread is pressed, making it easier for the loop to grow. Conversely, when the portion of the needle body 20 containing the deep groove 23c is pulled out of the fabric 35, the resistance of the thread sandwiched between the deep groove 23c and the fabric 35 is less, and therefore the loop does not easily grow.

[0054] Here, the first needle hooked by the looper (right needle N1) is installed at its highest position, so even when moved to the bottom stop position, it is inserted into the fabric 35 relatively shallowly. Since the loop is formed by rising from this state, the shallow groove 23b on the needle tip 21 side is used to form the loop. Therefore, even if the amount of needle rise for forming the loop (the amount of needle rise from the bottom stop position to when it meets the looper) is small, the shallow groove 23b can be used to make the loop grow sufficiently large.

[0055] Furthermore, since the last needle hooked by the looper (left needle N3) is installed at its lowest position, it inserts relatively deeply into the fabric 35 when moved to the bottom stop position. Because the loop is formed from this position, the deep groove 23c on the shank 11 side and the shallow groove 23b on the needle tip 21 side are used to form the loop. Therefore, even if the needle's rise for loop formation (the rise from the bottom stop position to when it meets the looper) is large, the loop will not grow excessively when the deep groove 23c passes through the fabric 35, and the loop can grow when the shallow groove 23b passes through the fabric 35. In other words, the deep groove 23c can suppress loop growth, thus preventing the loop from becoming too large and preventing skipped stitches caused by the loop tilting.

[0056] In this way, if the covered chain stitch sewing machine needle 10 of this embodiment is used, the difference in the size of the loop when it meets the looper can be reduced even when the needle is mounted at different heights. Skipped stitches can be prevented by making the loop sizes as consistent as possible.

Claims

1. A covered chain stitch sewing machine, wherein multiple loops are formed under the fabric by moving multiple needles arranged at varying heights in a direction orthogonal to the fabric feed direction up and down, and sewing is performed by hooking these multiple loops with a looper, wherein... The covered chain stitch sewing machine needle used in the aforementioned covered chain stitch sewing machine includes: a shank portion that is held in place when mounted on the sewing machine; and a needle body having a thread hole formed at its tip and being inserted and withdrawn relative to the fabric. A surface groove is formed on the needle body, extending from the opening edge of the thread hole toward the shank, and a notch is formed on the back side of the surface groove, forming a recess in the outline of the needle body. The surface groove has a stepped portion at a position closer to the shank than the notch portion, and the surface groove is formed in this stepped portion such that the depth of the groove increases as it moves from the tip side toward the shank. The step portion is formed in such a position that, when multiple covered chain stitch sewing machine needles are installed on the covered chain stitch sewing machine and moved to the lower stop point, the step portion does not penetrate the fabric in the covered chain stitch sewing machine needle installed at the highest position among the multiple covered chain stitch sewing machine needles, and the step portion penetrates the fabric in the covered chain stitch sewing machine needle installed at the lowest position among the multiple covered chain stitch sewing machine needles.

2. A sewing method using a covered chain stitch sewing machine, wherein a plurality of covered chain stitch sewing machine needles arranged at varying heights in a direction orthogonal to the fabric feed direction are moved up and down to form a plurality of loops under the fabric, and sewing is performed by hooking the plurality of loops with a looper, wherein... The covered chain stitch sewing machine needle includes: a shank that is held in place when mounted on the sewing machine; and a needle body having a thread hole formed at its tip and being inserted and withdrawn relative to the fabric. A surface groove is formed on the needle body, extending from the opening edge of the thread hole toward the shank, and a notch is formed on the back side of the surface groove, forming a recess in the outline of the needle body. The surface groove has a stepped portion at a position closer to the shank than the notch portion, and the surface groove is formed in this stepped portion such that the depth of the groove increases as it moves from the tip side toward the shank. The configuration is such that, when the highest-positioned cover chain stitch sewing machine needle among the plurality of cover chain stitch sewing machine needles is moved to the lower stop position, its stepped portion is not located below the fabric. The step portion is positioned below the fabric when the lowest-positioned cover chain stitch sewing machine needle among the plurality of cover chain stitch sewing machine needles is moved to the lower stop position.

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