Control method for preventing needle breakage in backstitch
By adjusting the rotation timing of the feeding motor and the tooth lifting motor, the problem of mismatch between the needle and the feeding teeth when the thick-foot is reversed, the effect of preventing the needle from hair and breaking the needle is achieved, and the normal thread retraction during the front seam is maintained, which improves the performance of the sewing machine.
Patent Information
- Application Number
- CN202510890929.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-30
- Publication Date
- 2025-08-12
AI Technical Summary
When sewing thick materials, the movement of the needle and feeding teeth in the reverse sewing mode leads to hair or breakage of the needle.
By independently driving the feeding motor and the tooth lifting motor, adjust the rotation timing of the feeding motor relative to the spindle, set the thick material back-slit mode, so that the feeding teeth complete the feeding action before the needle penetrates the fabric, and stop feeding the cloth when the needle comes out, avoiding the interaction force between the needle and the fabric.
Effectively prevent the needle from woven and broken when the thick material is inverted, maintain normal thread collection during the regular seam, and improve the competitiveness and production efficiency of the sewing machine.
Smart Images
Figure CN120465206A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of sewing machines, and in particular to a control method for preventing needle breakage in reverse sewing. Background Art
[0002] During the sewing process, the sewing machine will have multiple forward and reverse stitching to perform local reinforcement. When the thickness of the sewing fabric is thick, the needle is prone to hairiness and breakage during the reverse stitching mode. This is caused by the mismatch between the needle piercing timing and the feed timing of the feed dog during the reverse stitching. Figure 1 As shown, in the standard sewing mode of the prior art, when backstitching thick materials, the movement of the fabric 1 does not match the movement timing of the needle 2, resulting in the fabric 1 still moving horizontally under the drive of the feed dog during the movement of the needle 2 piercing and discharging the fabric, thereby colliding and interfering with the needle 2 in the horizontal direction, causing the needle 2 to bend during the movement, resulting in hairiness or even exceeding the load limit of the needle 2 in the horizontal direction, resulting in needle breakage. In response to this practical problem, existing solutions mainly rely on temporary measures such as the operator manually adjusting the fabric position or reducing the sewing speed. However, these methods not only increase the complexity of the operation, but also make it difficult to ensure sewing accuracy and cannot fundamentally solve the problem of broken needles. Summary of the Invention
[0003] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a control method for preventing needle breakage during reverse sewing, which can effectively avoid needle breakage during reverse sewing of thick materials.
[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:
[0005] The present invention provides a control method for reverse sewing and preventing needle breakage, in which a main shaft drives a machine needle to move up and down, a feeding motor is set to drive the feeding dog to move horizontally back and forth, and a tooth-lifting motor is set to drive the feeding dog to move up and down; a standard sewing mode is set in which the feeding motor and the tooth-lifting motor jointly drive the feeding dog to run in a standard elliptical trajectory; a thick material reverse sewing mode is set, and the thick material reverse sewing mode advances the rotation timing of the feeding motor relative to the main shaft in the standard sewing mode by a preset angle, and the rotation timing of the tooth-lifting motor relative to the main shaft remains unchanged, so that the feeding motor and the tooth-lifting motor jointly drive the feeding dog to run in a rectangular thick material reverse sewing trajectory, and in a feeding cycle in which the feed dog runs along the thick material reverse sewing trajectory, the moment when the feed dog completes the front and rear horizontal feeding is earlier than the moment when the needle penetrates the cloth; a cloth thickness threshold is set, and in the process of sewing in the standard sewing mode, when the thickness of the sewn cloth exceeds the cloth thickness threshold and the sewing process is reverse sewing, the standard sewing mode is switched to the thick material reverse sewing mode for sewing.
[0006] Preferably, the preset angle is 15°-20°.
[0007] Preferably, the standard sewing mode, the thick material reverse stitching mode and the fabric thickness threshold are stored in the control module. When the thickness of the sewn fabric does not exceed the fabric thickness threshold, or the thickness of the sewn fabric exceeds the fabric thickness threshold and the sewing process is not reverse stitching, the control module controls sewing based on the standard sewing mode; when the thickness of the sewn fabric exceeds the fabric thickness threshold and the sewing process is reverse stitching, the control module switches to controlling sewing based on the thick material reverse stitching mode.
[0008] Preferably, a detection sensor is provided for detecting the thickness of the sewing fabric, and the detection sensor is in communication with the control module. The control module selects the standard sewing mode or switches to the thick material reverse sewing mode according to the fabric thickness detected by the detection sensor.
[0009] Preferably, the detection sensor is a displacement sensor, and the displacement sensor is arranged on the presser foot mechanism.
[0010] Preferably, the detection sensor is a Hall detection element.
[0011] Compared with the prior art, the present invention has significant improvements:
[0012] The control method for reverse stitching and preventing needle breakage of the present invention switches the standard sewing mode to the thick material reverse stitching mode for sewing when the thickness of the sewn fabric exceeds the fabric thickness threshold and the sewing process is reverse stitching. The thick material reverse stitching mode adjusts the corresponding relationship between the feed motor angle and the spindle angle relative to the standard sewing mode. When the feed motor angle cycle remains unchanged, the overall rotation timing of the feed motor is advanced by a preset angle relative to the corresponding relationship of the spindle, and the corresponding relationship between the tooth lifting motor angle and the spindle angle remains unchanged, so that the feed dog completes the front and rear horizontal fabric feeding earlier, and the machine At the moment the needle penetrates the fabric, in the thick material reverse sewing mode, the feed dog has completed the horizontal feeding of the fabric in one feeding cycle. Even if the feed dog is still above the needle plate at this time, the subsequent movement of the feed dog is only to move down to under the needle plate without horizontal movement. Therefore, during the period from the needle penetrating the fabric to the needle exiting the fabric, the feed dog has no force on the fabric, the fabric remains in a relatively static state, and there is no interaction force between the fabric and the needle in the radial direction of the needle, thereby avoiding the phenomenon of needle hairiness and needle breakage in the reverse sewing process of thick materials, and playing the role of preventing needle breakage in reverse sewing. In addition, the reverse sewing mode for thick materials only advances the overall rotation timing of the feed motor relative to the main shaft, and the corresponding relationship between the tooth lifting motor angle and the main shaft angle remains unchanged. Compared with the adjustment method of synchronously advancing the overall corresponding relationship between the rotation timing of the feed motor and the rotation timing of the tooth lifting motor relative to the main shaft, this timing adjustment method will not cause adverse effects on the thread taking-up during the forward sewing. While preventing the needle from breaking during the reverse sewing of thick materials, it can also maintain the original movement relationship during the forward sewing to ensure normal thread taking-up, thereby improving the competitiveness of sewing machine products. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 This is a schematic diagram of the situation in which the timing of needle punching the cloth during backstitching of thick materials in the standard sewing mode in the prior art does not match the timing of feeding the materials by the feed dogs.
[0014] Figure 2 Schematic diagram of the control structure used in the control method for preventing needle breakage in reverse stitching according to an embodiment of the present invention.
[0015] Figure 3 yes Figure 2 Schematic diagram of the structure of the feeding part.
[0016] Figure 4 This is a schematic diagram of the corresponding relationship between the rotation angles of the feed motor and the main shaft in the standard sewing mode in the control method for preventing needle breakage during reverse sewing according to an embodiment of the present invention.
[0017] Figure 5 This is a schematic diagram of the corresponding relationship between the rotation angles of the feed motor and the main shaft in the thick material reverse sewing mode in the control method for preventing needle breakage during reverse sewing according to an embodiment of the present invention.
[0018] Figure 6 1 is a schematic diagram of the feed dog's running trajectory change when switching from a standard sewing mode to a heavy material reverse sewing mode in a control method for reverse sewing and preventing needle breakage in an embodiment of the present invention.
[0019] Figure 7 It is a control logic diagram of a control method for preventing needle breakage in reverse stitching according to an embodiment of the present invention.
[0020] The description of the accompanying drawings is as follows:
[0021] 1. Fabric
[0022] 2 needles
[0023] 3 Detection sensors
[0024] 100 spindle
[0025] 101 Spindle Motor
[0026] 200 needle bar mechanism
[0027] 300 presser foot mechanism
[0028] 301 Presser foot lift motor
[0029] 400 Feeding Motor
[0030] 500 feed dog
[0031] 600 tooth lifting motor DETAILED DESCRIPTION
[0032] The following is a further detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, and are not intended to limit the present invention.
[0033] In the description of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0034] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.
[0035] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.
[0036] like Figures 2 to 7 FIG. 1 is an embodiment of the control method for preventing needle breakage during reverse stitching provided by the present invention.
[0037] See also Figure 2 and Figure 3 In the control structure employed in the backstitching and needle break prevention control method of this embodiment, a spindle 100 drives the needle 2 up and down. Needle 2 is mounted at the lower end of a needle bar mechanism 200, above the needle plate. The spindle 100 is driven by a spindle motor 101, which in turn drives the needle 2 up and down through the needle bar mechanism 200. A presser foot mechanism 300 is also located above the needle plate and is driven by a presser foot lifter motor 301 to raise and lower the presser foot. Both the needle bar mechanism 200 and the presser foot mechanism 300 are conventional structures.
[0038] A feeding motor 400 is set to drive the feeding dog 500 to move horizontally back and forth, and a tooth-lifting motor 600 is set to drive the feeding dog 500 to move up and down. The horizontal back and forth movement and the up and down movement of the feeding dog 500 combine to form the motion trajectory of the feeding dog 500 when feeding cloth. By setting the feeding motor 400 and the tooth-lifting motor 600 independent of the main shaft 100 to respectively drive the feeding dog 500 to move horizontally back and forth and move up and down, the driving sources of the three, namely, the up and down movement of the needle 2, the horizontal back and forth movement of the feeding dog 500, and the up and down movement of the feeding dog 500, are all independent of each other. Then, the driving rules of the feeding motor 400 and the tooth-lifting motor 600 can be freely customized, so that a specific motion trajectory of the feeding dog 500 can be achieved by changing the rotation timing of the feeding motor 400 and / or the tooth-lifting motor 600 relative to the main shaft 1.
[0039] See also Figures 4 to 6 In the control method for reverse stitching and preventing needle breakage of this embodiment, a standard sewing mode, a thick material reverse stitching mode and a fabric thickness threshold are set.
[0040] Among them, the standard sewing mode is the standard sewing mode in the prior art, which is applicable to the sewing of conventional thinner fabrics and the sewing of relatively thicker fabrics when not in reverse stitching. In the standard sewing mode, the feed motor 400 and the lifting motor 600 jointly drive the feed dog 500 to run in a standard elliptical trajectory. This is the prior art and will not be elaborated in this article.
[0041] The heavy material reverse stitching mode advances the rotation timing of the feed motor 400 relative to the main shaft 100 in the standard sewing mode by a preset angle, while the rotation timing of the thread lifting motor 600 relative to the main shaft 100 remains unchanged. That is, the heavy material reverse stitching mode adjusts the corresponding relationship between the rotation angle of the feed motor 400 and the rotation angle of the main shaft 100 compared to the standard sewing mode. While the rotation period of the feed motor 400 remains unchanged, the overall rotation timing of the feed motor 400 relative to the main shaft 100 is advanced by a preset angle, while the corresponding relationship between the rotation angle of the thread lifting motor 600 and the rotation angle of the main shaft 100 remains unchanged. The resulting heavy material reverse stitching mode causes the feed motor 400 and the tooth lifting motor 600 to jointly drive the feed dog 500 to operate along a rectangular heavy material reverse stitching trajectory. Compared to the standard sewing mode, the heavy material reverse stitching mode advances the overall rotation timing of the feed motor 400 relative to the main shaft 100, thereby completing the forward and backward horizontal fabric feed earlier relative to the movement of the needle 2. Furthermore, during a feed cycle of the feed dog 500 operating along the heavy material reverse stitching trajectory, the time when the feed dog 500 completes the forward and backward horizontal fabric feed is earlier than the time when the needle 2 penetrates the fabric. Preferably, the preset angle by which the overall rotation timing of the feed motor 400 relative to the main shaft 100 in the heavy material reverse stitching mode is advanced by 15°-20° relative to the standard sewing mode.
[0042] During sewing in the standard sewing mode, when the thickness of the sewn fabric exceeds the fabric thickness threshold and the sewing process is reverse sewing, the standard sewing mode is switched to the thick material reverse sewing mode for sewing.
[0043] See also Figure 6 In the backstitching process for thick materials, when the needle 2 penetrates the fabric 1, in the standard trajectory of the standard sewing mode, the feed dog 500 has not yet completed the horizontal feeding of the fabric. Therefore, after the needle 2 penetrates the fabric 1, the feed dog 500 still feeds the fabric horizontally back and forth, causing the fabric 1 and the needle 2 to be squeezed in the radial direction of the needle 2. After the fabric 1 reaches a certain thickness, the interaction force between the needle 2 and the fabric 1 is greater than the yield limit of the needle 2, which causes the needle 2 to become hairy or even break. The control method for preventing needle breakage in reverse sewing of this embodiment switches from standard sewing mode to thick material reverse sewing mode for sewing when the thickness of the sewn fabric exceeds the fabric thickness threshold and the sewing process is reverse sewing. In the thick material reverse sewing process, at the moment when the needle 2 penetrates the fabric 1, in the thick material reverse sewing trajectory of the thick material reverse sewing mode, the feed dog 500 has completed the front and rear horizontal feeding within one feeding cycle. Even if the feed dog 500 is still above the needle plate at this time, the subsequent movement of the feed dog 500 is only to move down to below the needle plate without horizontal movement. Therefore, during the period from the needle 2 penetrating the fabric 1 to the needle 2 exiting the fabric 1, the feed dog 500 has no force on the fabric 1, and the fabric 1 remains in a relatively static state. There is no interaction force between the fabric 1 and the needle 2 in the radial direction of the needle 2, thereby avoiding the phenomenon of the needle 2 becoming hairy and breaking in the thick material reverse sewing process, thereby achieving the effect of preventing needle breakage in reverse sewing.
[0044] In the control method for preventing needle breakage during reverse sewing of the present embodiment, the reverse sewing mode for thick materials only advances the overall rotation timing of the feed motor 400 relative to the main shaft 100, and the corresponding relationship between the rotation angle of the tooth lifting motor 600 and the rotation angle of the main shaft 100 remains unchanged. Compared with the adjustment method of synchronously advancing the overall corresponding relationship between the rotation timing of the feed motor 400 and the rotation timing of the tooth lifting motor 600 relative to the main shaft 100, this timing adjustment method will not cause adverse effects on the thread taking-up during the forward sewing. While preventing the needle from breaking during reverse sewing of thick materials, it can also maintain the original motion relationship during forward sewing to ensure normal thread taking-up, thereby improving the competitiveness of sewing machine products.
[0045] In this embodiment, preferably, the standard sewing mode, the thick material reverse stitching mode and the cloth thickness threshold are stored in the control module. The control module is the existing electronic control structure of the existing sewing machine. When the thickness of the sewn fabric does not exceed the fabric thickness threshold, or the thickness of the sewn fabric exceeds the fabric thickness threshold and the sewing process is not reverse stitching, the control module controls the sewing based on the standard sewing mode, controls the feeding motor 400 and the tooth lifting motor 600 to jointly drive the feed dog 500 to run along the standard trajectory to feed the fabric. When the thickness of the sewn fabric exceeds the fabric thickness threshold and the sewing process is reverse stitching, the control module switches to controlling the sewing based on the thick material reverse stitching mode, controls the feeding motor 400 and the tooth lifting motor 600 to jointly drive the feed dog 500 to run along the thick material reverse stitching trajectory to feed the fabric.
[0046] In this embodiment, a detection sensor 3 is preferably provided for detecting the thickness of the fabric being sewn. The detection sensor 3 is in communication with the control module. The detection sensor 3 transmits the detected fabric thickness information to the control module. The control module receives the information and obtains the fabric thickness. The control module selects the standard sewing mode or switches to the thick material reverse stitching mode based on the fabric thickness detected by the detection sensor 3 to control the feed motor 400 and the tooth lifting motor 600 to jointly drive the feed dog 500. By identifying the fabric thickness by the detection sensor 3, the standard sewing mode or the thick material reverse stitching mode can be adaptively adjusted according to the changes in fabric thickness during the sewing process, thereby ensuring that the sewing process can proceed normally and prevent needle breakage when the reverse stitching process is used on thick materials. At the same time, the sewing machine can ensure beautiful stitches, improve actual production efficiency, be more stable and faster than manual operation, and be more competitive in the market. It can also expand the applicability of the sewing machine to sewing fabrics, improve the product process coverage, and reduce the limitations of the sewing machine in sewing work under special processes.
[0047] In this embodiment, the detection sensor 3 is preferably a displacement sensor, which is disposed on the presser foot mechanism 300. Preferably, the detection sensor 3 is a Hall effect sensor. During the sewing process, the height to which the presser foot rises is equal to the thickness of the fabric within the sewing area. Therefore, providing a displacement sensor on the presser foot mechanism 300 to detect changes in the presser foot's height allows for real-time detection of fabric thickness.
[0048] See also Figure 7 The control logic of the control method for preventing needle breakage during reverse stitching of this embodiment includes the following steps.
[0049] Step S1: Place the fabric and lower the presser foot.
[0050] Step S2: Obtaining the thickness of the fabric: The thickness is detected by the detection sensor 3 and transmitted to the control module.
[0051] Step S3: Determine whether the fabric thickness is within the fabric thickness threshold: if so, execute step S4; if not, execute step S6.
[0052] Step S4, determining whether the sewing process is reverse stitching: if so, executing step S5; if not, executing step S6.
[0053] Step S5: Switch from the standard sewing mode to the heavy material reverse stitching mode for sewing, and then return to step S4.
[0054] Step S6: Sewing in a standard sewing mode.
[0055] This allows for fully automatic adaptive adjustment during the sewing process.
[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.
Claims
1. A control method for preventing needle breakage during reverse sewing, characterized in that: The main shaft drives the needle to move up and down, a feeding motor is set to drive the feed dog to move horizontally forward and backward, and a tooth lifting motor is set to drive the feed dog to move up and down; A standard sewing mode is set in which the feed motor and the tooth lifting motor jointly drive the feed dog to run in a standard elliptical trajectory; A thick material reverse sewing mode is set, wherein the thick material reverse sewing mode advances the rotation timing of the feed motor relative to the main shaft in the standard sewing mode by a preset angle, and the rotation timing of the tooth lifting motor relative to the main shaft remains unchanged, so that the feed motor and the tooth lifting motor jointly drive the feed dog to run in a rectangular thick material reverse sewing trajectory, and in a feed cycle of the feed dog running along the thick material reverse sewing trajectory, the time when the feed dog completes the front and rear horizontal feeding is earlier than the time when the needle penetrates the fabric; A fabric thickness threshold is set. During sewing in the standard sewing mode, when the thickness of the sewn fabric exceeds the fabric thickness threshold and the sewing process is reverse sewing, the standard sewing mode is switched to the thick material reverse sewing mode for sewing.
2. The control method for preventing needle breakage during reverse stitching according to claim 1, characterized in that: The preset angle is 15°-20°.
3. The control method for preventing needle breakage during reverse stitching according to claim 1, characterized in that: The standard sewing mode, the thick material reverse stitching mode and the fabric thickness threshold are stored in the control module. When the thickness of the sewn fabric does not exceed the fabric thickness threshold, or the thickness of the sewn fabric exceeds the fabric thickness threshold and the sewing process is not reverse stitching, the control module controls sewing based on the standard sewing mode; when the thickness of the sewn fabric exceeds the fabric thickness threshold and the sewing process is reverse stitching, the control module switches to controlling sewing based on the thick material reverse stitching mode.
4. The control method for preventing needle breakage during reverse stitching according to claim 3, characterized in that: A detection sensor is provided for detecting the thickness of the sewing fabric. The detection sensor is in communication with the control module. The control module selects the standard sewing mode or switches to the thick material reverse stitching mode according to the fabric thickness detected by the detection sensor.
5. The control method for preventing needle breakage during reverse stitching according to claim 4, characterized in that: The detection sensor is a displacement sensor, and the displacement sensor is arranged on the presser foot mechanism.
6. The control method for preventing needle breakage during reverse stitching according to claim 5, characterized in that: The detection sensor is a Hall detection component.