Method of sewing a fancy stitch seam and electronic zigzag sewing machine

Abstract

The present application relates to a kind of fancy stitch seam sewing method and electronic zigzag sewing machine, it relates to sewing machine technical field, for solving the technical problem of pattern breakage caused by spacing error or missing sewing of reverse feed.The fancy stitch seam sewing method of the present application makes the first positive feed spacing greater than the second positive feed spacing, and the reverse feed spacing is greater than the second positive feed spacing, so that in each step, the position of the needle dropped along the feed direction of the cloth according to the reverse feed spacing is always located in front of the position when the needle is dropped according to the first positive feed spacing, even in the case of the same level of feed spacing error or needle jitter as in the past, pattern breakage will not occur, thereby solving the technical problem of pattern breakage caused by spacing error or missing sewing of reverse feed in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewing machine technical field, and particularly relates to a fancy stitch joint sewing method and an electronic zigzag sewing machine. BACKGROUND

[0002] As shown in the figure, the existing fancy stitch sewing method is to make the needle swing left and right to drop the needle at position 1, position 2, position 3 and position 4 respectively, so as to form a fancy stitch on the left fabric and the right fabric, wherein the forward feeding interval A' and the forward feeding interval B' are substantially the same, and the reverse feeding interval C' is slightly larger than the forward feeding interval B'. Figure 1 As shown in the figure, the line shown is normal in the prior art. Figure 2

[0003] However, the above-mentioned sewing method is prone to the following problems, that is, needle shaking is easily generated when the reverse feeding interval is wrong or the sewing is missed, and the needle drop of the reverse feeding becomes smaller than the forward feeding of the needle before position 1, thereby causing the needle drop defect. Figure 3 As shown in the figure, when the needle drop is performed at the reverse feeding interval C', the correct needle drop position should be at P1 position, but due to the error of the reverse feeding interval or the missed sewing, the actual needle drop position becomes P2; that is, when the needle actually drops, the needle is not dropped according to the correct reverse feeding interval C', but is dropped according to the wrong reverse feeding interval C'', thereby making the needle drop position become P2, and the interval between the correct needle drop position P1 and the wrong needle drop position P2 is E. The deviation of the above-mentioned needle drop position will cause the pattern to break, Figure 4 The two places circled in the figure show the phenomenon of pattern breaking. SUMMARY

[0004] The present application provides a fancy stitch joint sewing method and an electronic zigzag sewing machine, which are used to solve the technical problem of pattern breaking caused by the error of the reverse feeding interval or the missed sewing.

[0005] According to the first aspect of the present application, the present application provides a fancy stitch joint sewing method used by an electronic zigzag sewing machine which can change and adjust the interval of feeding fabric by each needle and make the needle swing in the direction intersecting with the fabric feeding direction, so as to form a line on the fabric, which comprises the following operation steps:

[0006] Step 1: make the needle swing in the first direction and drop the needle according to the first forward feeding interval and the second forward feeding interval respectively;

[0007] ​Step 2: Take the last stitch position in Step 1 as the starting position for changing the needle swing direction and the fabric feed direction. Swing the needle in the second direction, which is opposite to the first direction, while dropping the needle at the reverse feed interval.

[0008] Step 3: Using the last stitch position in Step 2 as the starting position for changing the fabric feed direction, swing the needle in the second direction while dropping the needle according to the first forward feed interval and the second forward feed interval respectively.

[0009] Step 4: Take the last stitch position in Step 3 as the starting position for changing the needle swing direction and the fabric feed direction. Swing the needle in the first direction while dropping the needle at the reverse feed interval.

[0010] Step 5: Repeat steps 1 to 4 until the end;

[0011] The first forward feed interval is greater than the second forward feed interval, and the reverse feed interval is greater than the second forward feed interval, so that in each step, along the fabric feeding direction, the position where the needle falls according to the reverse feed interval is always in front of the position where the needle falls according to the first forward feed interval.

[0012] In one embodiment, the reverse feed interval is smaller than the first forward feed interval.

[0013] In one embodiment, when the needle is oscillating in a first direction while dropping the needle at a second positive feed interval, the stitch is located on the fabric to the left of the baseline.

[0014] When the needle swings in the second direction while dropping the needle at the second positive feed interval, the stitch is located on the fabric to the right of the baseline.

[0015] When the needle swings in the first direction while dropping the needle at the first positive feed interval, or when the needle swings in the second direction while dropping the needle at the reverse feed interval, the needle drops in the unfathomable portion between the fabric to the left of the baseline and the fabric to the right of the baseline, and the needle drops closer to the fabric to the left of the baseline.

[0016] When the needle swings in the second direction while dropping the needle at the first forward feed interval, or when the needle swings in the first direction while dropping the needle at the reverse feed interval, the needle drops in the unfathomable portion between the fabric to the left of the baseline and the fabric to the right of the baseline, with the needle dropping closer to the fabric to the right of the baseline.

[0017] In one implementation, step 1 is divided into the following sub-steps:

[0018] Step 1-1: Swing the needle in the first direction while dropping the needle according to the first positive feed interval;

[0019] Step 1-2: Starting from the needle drop position in Step 1-1, continue to swing the needle in the first direction while dropping the needle according to the second positive feed interval.

[0020] In one implementation, step 3 is divided into the following sub-steps:

[0021] Step 3-1: Using the needle drop position in Step 2 as the starting position for changing the fabric feed direction, make the needle swing in the second direction while dropping the needle according to the first positive feed interval;

[0022] Step 3-2: Starting from the needle drop position in Step 3-1, continue to swing the needle in the second direction while dropping the needle according to the second positive feed interval.

[0023] According to a second aspect of the present invention, an electronic serrated sewing machine is provided, comprising a fabric feeding device capable of adjusting the spacing of the fed fabric on a per-needle basis, and a needle oscillation mechanism for oscillating the needle in a direction intersecting the fabric feeding direction.

[0024] Stitches are formed on the fabric through the cooperation of the fabric feeding device and the needle oscillation mechanism, which form fancy stitch seams by performing the following steps:

[0025] Step 1: While swinging the needle in the first direction, drop the needle according to the first positive feed interval and the second positive feed interval respectively;

[0026] Step 2: Take the last stitch position in Step 1 as the starting position for changing the needle swing direction and the fabric feed direction. Swing the needle in the second direction, which is opposite to the first direction, while dropping the needle at the reverse feed interval.

[0027] Step 3: Using the last stitch position in Step 2 as the starting position for changing the fabric feed direction, swing the needle in the second direction while dropping the needle according to the first forward feed interval and the second forward feed interval respectively.

[0028] Step 4: Take the last stitch position in Step 3 as the starting position for changing the needle swing direction and the fabric feed direction. Swing the needle in the first direction while dropping the needle at the reverse feed interval.

[0029] Step 5: Repeat steps 1 to 4 until the end;

[0030] The first forward feed interval, the second forward feed interval, and the reverse feed interval can each have their set values ​​changed.

[0031] Compared with the prior art, the advantage of the present invention is that by making the first forward feed distance greater than the second forward feed distance, and the reverse feed distance greater than the second forward feed distance, in each step, the position where the needle falls according to the reverse feed distance along the fabric feed direction is always in front of the position where the needle falls according to the first forward feed distance. Therefore, even if the same level of feed distance error or needle jitter occurs as in the past, the pattern will not break, thus solving the technical problem of pattern breakage caused by reverse feed distance error or missed sewing in the prior art. Attached Figure Description

[0032] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0033] Figure 1 This is a schematic diagram of the needle's landing position during needle swing in existing technology;

[0034] Figure 2 It is a schematic diagram of the correct line trace formed in the prior art;

[0035] Figure 3 This is a schematic diagram of erroneous lines formed in the prior art;

[0036] Figure 4 This is a schematic diagram of pattern cracking in existing technology;

[0037] Figure 5 This is a schematic diagram of the stitches in the sewing method of the present invention;

[0038] Figure 6 and Figure 7 This is a schematic diagram of the pattern formed after sewing using the sewing method of the present invention. Detailed Implementation

[0039] The invention will now be further described with reference to the accompanying drawings.

[0040] According to a first aspect of the present invention, the present invention provides a method for sewing fancy stitch seams, which is a fancy stitch seam method used by an electronic sawtooth sewing machine that forms stitches on fabric through the cooperation of a fabric feeding device capable of adjusting the spacing of the fed fabric on a unit of each stitch (needle) and a needle oscillation mechanism that causes the needle to oscillate in a direction intersecting the fabric feeding direction.

[0041] First, the directions of the present invention are defined. It is understood that these definitions are for comprehension purposes only and should not be construed as limiting the invention.

[0042] The above-mentioned fabric feed direction is Figure 5The Y-axis direction is shown. More specifically, along... Figure 5 The positive Y-axis direction is the positive feed direction, and the negative Y-axis direction is the reverse feed direction. The direction of needle oscillation can be a direction relative to the Y-axis that deviates from the negative X-axis (i.e., to the left), or a direction relative to the Y-axis that deviates from the positive X-axis (i.e., to the right).

[0043] Specifically, the fancy stitch seam method of the present invention includes the following operation steps.

[0044] First, perform step 1, which is as follows.

[0045] The needle is oscillating in the first direction while being dropped according to the first positive feed interval and the second positive feed interval.

[0046] Step 1 above can be further divided into step 1-1 and step 1-2.

[0047] Specifically, step 1-1 involves swinging the needle in the first direction while dropping the needle at the first positive feed interval. Step 1-2 involves starting from the needle dropping position in step 1-1, continuing to swing the needle in the first direction while dropping the needle at the second positive feed interval.

[0048] The first direction can be, for example, to the left. The first positive feed distance is as follows: Figure 5 As shown in Figure A, the second positive spacing is as follows: Figure 5 B is shown.

[0049] like Figure 5 As shown, the initial coordinates of the needle are (X1, Y1). Starting from (X1, Y1), the needle is swung to the left while simultaneously dropping the needle according to the first positive feed interval A. The coordinates of the needle dropping position at this point are... Figure 5 At point (X2, Y2), it can be understood that A = |Y2 - Y1|. The trace formed from (X1, Y1) to (X2, Y2) is as follows. Figure 5 As shown by the thick black solid line.

[0050] Furthermore, starting from (X2, Y2), the needle continues to swing to the left while simultaneously dropping the needle according to the second positive feed interval B. The coordinates of the dropping position at this point are: Figure 5 At point (X3, Y3), as shown. Understandably, B = |Y3 - Y2|. The line trace formed from (X2, Y2) to (X3, Y3) is as follows... Figure 5 As shown by the thick black solid line.

[0051] In steps 1-1 and 1-2 above, the fabric is fed in the positive Y-axis direction.

[0052] Next, proceed to step 2, which is as follows.

[0053] Taking the last stitch position in step 1 as the starting position for changing the needle swing direction and the fabric feed direction, the needle swings in a second direction opposite to the first direction while dropping the needle at the reverse feed interval.

[0054] The second direction can be a direction relative to the Y-axis, biased towards the positive X-axis, i.e., to the right. The reverse feed interval is as follows: Figure 5 C is shown.

[0055] like Figure 5 As shown, the last stitch in step 1 lands at (X3, Y3). Therefore, (X3, Y3) is the starting point for the change in the needle swing direction and the fabric feed direction. In other words, starting at (X3, Y3), the needle swing direction begins to change (i.e., from left to right in step 1), and the fabric feed direction also begins to change (i.e., from the positive Y-axis direction in step 1 to the negative Y-axis direction).

[0056] Specifically, starting at (X3, Y3), the needle is swung to the left while simultaneously dropping the needle at a reverse feed interval C. The coordinates of the dropped needle position at this point are: Figure 5 The diagram shows (X4, Y4). It can be understood that C = |Y3 - Y4|. The trace formed from (X3, Y3) to (X4, Y4) is as follows... Figure 5 As shown by the thick black solid line.

[0057] It should be noted that starting from (X3, Y3), the needle swing direction changes, that is, in step 2, the needle swing direction changes to the right; at the same time, the fabric feed direction also changes, that is, in step 2, the fabric feed direction changes to the negative Y-axis direction.

[0058] Next, proceed to step 3, which is as follows.

[0059] Taking the last stitch position in step 2 as the starting position for changing the fabric feed direction, the needle swings in the second direction while dropping stitches according to the first forward feed interval and the second forward feed interval respectively.

[0060] Step 3 above can be further divided into step 3-1 and step 3-2.

[0061] Step 3-1 is to take the needle drop position in Step 2 as the starting position for changing the fabric feed direction, so that the needle swings in the second direction while dropping the needle according to the first positive feed interval. Step 3-2 is to start from the needle drop position in Step 3-1, so that the needle continues to swing in the second direction while dropping the needle according to the second positive feed interval.

[0062] Since the last stitch in step 2 above landed at (X3, Y3), (X3, Y3) marks the beginning of the change in the fabric feed direction. However, the needle swing direction does not change in this step.

[0063] Therefore, starting at (X3, Y3), the fabric feed direction changes from the negative Y-axis direction in step 2 to the positive Y-axis direction; and the needle swings to the right while dropping the needle according to the first positive feed interval A. The coordinates of the needle dropping position at this point are: Figure 5 The given (X5, Y5) is shown. It can be understood that A = |Y5 - Y4|. The line trace formed from (X4, Y4) to (X5, Y5) is as follows... Figure 5 As shown by the thick black solid line.

[0064] Furthermore, starting from (X5, Y5), the needle continues to swing to the right while dropping the needle according to the second positive feed interval B. The coordinates of the dropping position at this point are: Figure 5 At point (X6, Y6), it can be understood that B = |Y6 - Y5|. The line trace formed from (X5, Y5) to (X6, Y6) is as follows... Figure 5 As shown by the thick black solid line.

[0065] It should be noted that starting from (X4, Y4), the needle swing direction does not change, that is, in step 3 (including steps 3-1 and 3-2), the needle swing direction is the same as in step 2, which is to the right; however, the fabric feed direction has changed, that is, in steps 3-1 and 3-2, the fabric feed direction is changed to the positive Y-axis direction.

[0066] Next, proceed to step 4, which is as follows.

[0067] The position of the last stitch in step 3 is taken as the starting point for the change of the needle swing direction and the fabric feed direction. The needle swings in the first direction while dropping the needle at the reverse feed interval.

[0068] Since the last stitch in step 3 above landed at (X6, Y6), the direction of the needle swing begins to change from (X6, Y6) (i.e., from right to left in step 3), and the fabric feed direction also begins to change (i.e., from the positive Y-axis direction in step 3 to the negative Y-axis direction). Specifically, starting at (X6, Y6), the needle swings to the left while landing at a reverse feed interval C. The coordinates of the landing position at this point are... Figure 5 The diagram shows (X7, Y7). It can be understood that C = |Y7 - Y6|. The trace formed from (X6, Y6) to (X7, Y7) is as follows... Figure 5 As shown by the thick black solid line.

[0069] It should be noted that starting from (X6, Y6), the needle swing direction changes, that is, in step 4, the needle swing direction changes to the left; at the same time, the fabric feed direction also changes, that is, in step 4, the fabric feed direction changes to the negative Y-axis direction.

[0070] Step 5: Repeat steps 1 through 4 until finished.

[0071] like Figure 5 As shown, steps 1-4 form a loop. The next loop starts with (X7, Y7) as the starting coordinate position of the needle and executes steps 1 to 4 until the end.

[0072] In the above steps, the first forward feed spacing A is greater than the second forward feed spacing B, while the reverse feed spacing C is greater than the second forward feed spacing B, thus ensuring that in each step, along the fabric feed direction (e.g., ... Figure 5 (As shown in the positive Y-axis direction), the position where the needle falls at the reverse feed interval C is always ahead of the position where the needle falls at the first positive feed interval A. For example... Figure 2 An upward arrow indicates the front (positive Y-axis direction), and a downward arrow indicates the back (negative Y-axis direction).

[0073] Understandably, the position where the needle falls at the reverse feed interval C is always ahead of the position where it falls at the first positive feed interval A. This means that the Y-coordinate of the position where the needle falls at the reverse feed interval C is greater than the Y-coordinate of the position where the needle falls at the first positive feed interval A. For example... Figure 6 The y-coordinate of (X4, Y4) is Y4 = -2, while the y-coordinate of (X2, Y2) is Y2 = -4. Therefore, (X4, Y4) is in front of (X2, Y2), and the distance between (X4, Y4) and (X2, Y2) is D, where D = |Y4 - Y2|.

[0074] Therefore, the inventive concept of this invention lies in making the reverse feed distance C greater than the second forward feed distance B, so that the difference D between the needle landing coordinates of the second forward feed distance B and the reverse feed distance C (see...) Figure 7 The difference between the coordinate needle placement and that in the prior art (i.e.) Figure 5 The |C'-B'| shown is larger, so that even if the same level of feed pitch error or needle jitter occurs as before, pattern breakage will not occur (because the position when the needle falls according to the reverse feed pitch is always in front of the position when the needle falls according to the first positive feed pitch A).

[0075] like Figure 5 As shown, the patterns formed on the left and right fabrics using the sewing method of the present invention are as follows: the patterns are arranged tightly and evenly, and there is no phenomenon of pattern breakage. Figure 5Similarly, no cracking of the pattern was observed when the pattern was formed using the method of this invention.

[0076] In some specific embodiments, during the above steps, when the needle swings in a first direction (to the left) while simultaneously dropping the needle at a second positive feed interval B, the stitch is located on the fabric to the left of the baseline. For example... Figure 5 The (X3, Y3) shown is located on the fabric to the left of the baseline.

[0077] When the needle swings in the second direction (to the right) while dropping the needle at the second positive feed interval B, the stitch is located on the fabric to the right of the baseline. For example... ​ The (X6, Y6) shown is located on the fabric to the left of the baseline.

[0078] When the needle swings in the first direction (to the left) while dropping the needle at the first forward feed interval A, or when the needle swings in the second direction (to the right) while dropping the needle at the reverse feed interval C, the needle drop position is located on the unfabricated portion of the fabric between the left and right sides of the baseline, with the needle drop position closer to the left side of the baseline. For example... ​ The (X2, Y2) and (X4, Y4) shown are both located in the unfabricated portion between the fabric to the left of the baseline and the fabric to the right of the baseline, and the needle drops are close to the fabric to the left of the baseline.

[0079] When the needle swings in the second direction (to the right) while dropping the needle at the first forward feed interval A, or when the needle swings in the first direction (to the left) while dropping the needle at the reverse feed interval C, the needle drop position is located on the unfabricated portion of the fabric between the left and right sides of the baseline, with the needle drop position closer to the right side of the baseline. For example... ​ The (X5, Y5) and (X7, Y7) shown are both located in the unfabricated portion between the fabric to the left of the baseline and the fabric to the right of the baseline, and the needles are placed closer to the fabric to the left of the baseline.

[0080] According to a second aspect of the present invention, an electronic sawtooth sewing machine is provided, comprising a fabric feeding device capable of adjusting the spacing of the fed fabric on a per-needle basis and a needle oscillation mechanism for oscillating the needle in a direction intersecting the fabric feeding direction, wherein stitches are formed on the fabric through the cooperation of the fabric feeding device and the needle oscillation mechanism, and fancy stitch seams are formed by performing the following steps.

[0081] Step 1: Swing the needle in the first direction while dropping the needle according to the first positive feed interval and the second positive feed interval respectively.

[0082] Step 2: Using the last stitch position in Step 1 as the starting point for changing the needle swing direction and the fabric feed direction, make the needle swing in the second direction opposite to the first direction while dropping the needle at the reverse feed interval.

[0083] Step 3: Using the last stitch position in Step 2 as the starting position for changing the fabric feed direction, make the needle swing in the second direction while dropping stitches according to the first forward feed interval and the second forward feed interval respectively.

[0084] Step 4: Take the last stitch position in Step 3 as the starting position for changing the needle swing direction and the fabric feed direction. Make the needle swing in the first direction while dropping the needle at the reverse feed interval.

[0085] Step 5: Repeat steps 1 through 4 until finished.

[0086] The first forward feed interval, the second forward feed interval, and the reverse feed interval can each have their set values ​​changed.

[0087] It should be noted that the above-mentioned fabric feeding device and needle swing mechanism can all adopt existing devices and mechanisms, and the present invention will not elaborate on them further.

[0088] In some specific embodiments, the first forward feed spacing A can be 4cm, the second forward feed spacing B can be 1cm, and the reverse feed spacing C can be 3cm.

[0089] Furthermore, the total swing amplitude of the needle can be 8 cm. It should be noted that the amplitude of the swing is the same each time the needle swings in the first direction; that is, the amplitude of a single swing is the same. Similarly, the amplitude of the swing is the same each time the needle swings in the second direction. For example, when the needle swings in the first direction from (X1, Y1) to (X2, Y2) and lands at (X2, Y2), the amplitude of a single swing is |X2 - X1| = 2. When the needle swings in the first direction from (X2, Y2) to (X3, Y3) and lands at (X3, Y3), the amplitude of a single swing is still |X3 - X2| = 2.

[0090] It is understood that the above values ​​are for illustrative purposes only and should not be construed as limiting the invention. In practical applications, the first forward feed interval, the second forward feed interval, and the reverse feed interval can all be set to different values ​​according to actual needs, and the invention does not limit their values.

[0091] Furthermore, the fabric feeding device in the electronic saw sewing machine of the present invention can adopt the same or similar structural form as that described in the sewing machine disclosed in Chinese Patent CN106544793A.

[0092] Specifically, the fabric feeding device of the present invention can, for example, adopt the structural form of the feeding device disclosed in Chinese Patent CN106544793A. The fabric feeding device may include feed teeth, a feed table, a horizontal feed mechanism, and a vertical feed mechanism. The feed teeth transport the fabric along a predetermined direction. The feed table supports the feed teeth. The horizontal feed mechanism is connected to and driven by a sewing machine motor, thereby transmitting a horizontal reciprocating motion to the feed table. The vertical feed mechanism applies a vertical reciprocating motion to the feed table.

[0093] The horizontal feed mechanism has a feed regulating motor that adjusts the pitch of the reciprocating motion of the feed table in the horizontal direction, which is driven by the sewing machine motor. The vertical feed mechanism has a vertical feed motor that drives the reciprocating motion of the feed table in the vertical direction.

[0094] The electronic sawtooth sewing machine of the present invention may further include a control device that controls the feed adjustment motor and the up and down feed motor to perform the fabric feeding action achieved by the feed teeth.

[0095] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for sewing fancy stitch seams, comprising a method for forming stitches on fabric using an electronic sawtooth sewing machine, characterized in that the stitches are formed through the cooperation of a fabric feeding device capable of adjusting the spacing of the fed fabric on a per-stitch basis and a needle oscillation mechanism that causes the needle to oscillate in a direction intersecting the fabric feeding direction. The following steps are included: Step 1: While swinging the needle in the first direction, drop the needle according to the first positive feed interval and the second positive feed interval respectively; Step 2: Take the last stitch position in Step 1 as the starting position for changing the needle swing direction and the fabric feed direction. Swing the needle in the second direction, which is opposite to the first direction, while dropping the needle at the reverse feed interval. Step 3: Using the last stitch position in Step 2 as the starting position for changing the fabric feed direction, swing the needle in the second direction while dropping the needle according to the first forward feed interval and the second forward feed interval respectively. Step 4: Take the last stitch position in Step 3 as the starting position for changing the needle swing direction and the fabric feed direction. Swing the needle in the first direction while dropping the needle at the reverse feed interval. Step 5: Repeat steps 1 to 4 until the end; The first forward feed interval is greater than the second forward feed interval, and the reverse feed interval is greater than the second forward feed interval, so that in each step, along the fabric feeding direction, the position where the needle falls according to the reverse feed interval is always in front of the position where the needle falls according to the first forward feed interval.

2. The sewing method for fancy stitch seams according to claim 1, characterized in that, The reverse feed interval is less than the first forward feed interval.

3. The sewing method for fancy stitch seams according to claim 1 or 2, characterized in that, When the needle swings in the first direction while dropping the needle at the second positive feed interval, the stitch is located on the fabric to the left of the baseline. When the needle swings in the second direction while dropping the needle at the second positive feed interval, the stitch is located on the fabric to the right of the baseline. When the needle swings in the first direction while dropping the needle at the first positive feed interval, or when the needle swings in the second direction while dropping the needle at the reverse feed interval, the needle drops in the unfathomable portion between the fabric to the left of the baseline and the fabric to the right of the baseline, and the needle drops closer to the fabric to the left of the baseline. When the needle swings in the second direction while dropping the needle at the first forward feed interval, or when the needle swings in the first direction while dropping the needle at the reverse feed interval, the needle drops in the unfathomable portion between the fabric to the left of the baseline and the fabric to the right of the baseline, with the needle dropping closer to the fabric to the right of the baseline.

4. The sewing method for fancy stitch seams according to claim 1 or 2, characterized in that, Step 1 is divided into the following sub-steps: Step 1-1: Swing the needle in the first direction while dropping the needle according to the first positive feed interval; Step 1-2: Starting from the needle drop position in Step 1-1, continue to swing the needle in the first direction while dropping the needle according to the second positive feed interval.

5. The sewing method for fancy stitch seams according to claim 1 or 2, characterized in that, Step 3 is divided into the following sub-steps: Step 3-1: Using the needle drop position in Step 2 as the starting position for changing the fabric feed direction, make the needle swing in the second direction while dropping the needle according to the first positive feed interval; Step 3-2: Starting from the needle drop position in Step 3-1, continue to swing the needle in the second direction while dropping the needle according to the second positive feed interval.

6. An electronic sawtooth sewing machine, comprising a fabric feeding device capable of adjusting the spacing of the fed fabric on a per-stitch basis, and a needle oscillation mechanism for oscillating the needle in a direction intersecting the fabric feeding direction. The stitches are formed on the fabric through the cooperation of the fabric feeding device and the needle oscillation mechanism, characterized in that... To create a fancy stitch seam, follow these steps: Step 1: While swinging the needle in the first direction, drop the needle according to the first positive feed interval and the second positive feed interval respectively; Step 2: Take the last stitch position in Step 1 as the starting position for changing the needle swing direction and the fabric feed direction. Swing the needle in the second direction, which is opposite to the first direction, while dropping the needle at the reverse feed interval. Step 3: Using the last stitch position in Step 2 as the starting position for changing the fabric feed direction, swing the needle in the second direction while dropping the needle according to the first forward feed interval and the second forward feed interval respectively. Step 4: Take the last stitch position in Step 3 as the starting position for changing the needle swing direction and the fabric feed direction. Swing the needle in the first direction while dropping the needle at the reverse feed interval. Step 5: Repeat steps 1 to 4 until the end; The first forward feed interval is greater than the second forward feed interval, and the reverse feed interval is greater than the second forward feed interval, so that in each step, along the fabric feeding direction, the position where the needle falls according to the reverse feed interval is always in front of the position where the needle falls according to the first forward feed interval.

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