Thread cutting control device capable of preventing cloth from being cut by mistake and sewing machine

Abstract

The invention relates to the technical field of sewing, in particular to a thread cutting control device capable of preventing cloth from being cut by mistake and a sewing machine. The thread trimming control device comprises a needle plate, a scissor assembly and a sensor assembly, wherein the needle plate is provided with a first end and a second end, and the first end and the second end are used for allowing cloth to move from the first end to the second end; the scissor assembly is arranged near the needle plate; the sensor assembly comprises a first emitter, a second emitter and a receiver, the receiver is arranged on the needle plate, and the first emitter and the second emitter are arranged above the needle plate and are arranged on the side, close to the second end, of the scissor assembly and the side, close to the first end, of the scissor assembly respectively; the front end of the cloth moves to the receiver, the receiver generates a first signal, and the scissor assembly implements / stops trimming according to the first signal; the rear end of the cloth moves to the receiver, the receiver generates a second signal, and the scissor assembly implements / stops trimming according to the second signal. The thread cutting operation at the front end and the rear end of the cloth can be accurately controlled, and the cloth is prevented from being cut by mistake.

Description

Technical Field

[0001] This application relates to the field of sewing technology, and in particular to a thread-cutting control device and sewing machine for preventing accidental fabric cutting. Background Technology

[0002] Automatic thread trimming is a standard feature of modern computerized sewing machines, significantly improving work efficiency by automatically cutting off the thread ends after sewing. However, in actual sewing production, especially when handling fabrics of specific shapes or performing certain special processes, sewing machines occasionally accidentally cut the fabric itself.

[0003] To address this issue, the current market solution commonly involves installing a sensor near the thread cutter or below the needle plate, with a transmitter positioned above it, forming a photoelectric detection device. For example, when the front end of the fabric blocks the receiver, the receiver sends a signal to stop thread cutting; when the rear end of the fabric moves away from the receiver, the distance traveled is determined based on the stitch count, and thread cutting begins after a preset time. However, this solution only accurately detects the front or rear end of the fabric; the other end requires other structural methods, such as the stitch count, to determine the fabric's travel distance and perform thread cutting. In actual sewing, fabric shapes are complex and varied, and relying solely on judging the fabric's travel distance for thread cutting still carries the risk of accidental fabric cuts. Summary of the Invention

[0004] Therefore, it is necessary to provide a thread-cutting control device and sewing machine that can solve the above problems and prevent accidental fabric cutting.

[0005] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0006] This application relates to the field of sewing technology, and in particular to a thread-cutting control device and sewing machine for preventing accidental fabric cutting.

[0007] A thread-cutting control device for preventing accidental fabric cutting, used in a sewing machine, the thread-cutting control device comprising:

[0008] A needle plate having a first end and a second end, the needle plate being used to allow fabric to move along it from the first end to the second end;

[0009] A scissor assembly is positioned near the needle plate and is used to cut threads on the fabric.

[0010] A sensor assembly includes a first transmitter, a second transmitter, and a receiver. The receiver is disposed on the needle plate. The first transmitter and the second transmitter are disposed above the needle plate. The first transmitter is disposed on the side of the scissor assembly near the second end. The second transmitter and the receiver are disposed on the side of the scissor assembly near the first end. Both the first transmitter and the second transmitter are oriented toward the receiver.

[0011] The fabric has a front end and a rear end. When the front end moves to the receiver, the receiver cooperates with the second transmitter to generate a first signal, and the scissors assembly performs / stops cutting the thread according to the first signal. When the rear end moves to the receiver, the receiver cooperates with the first transmitter to generate a second signal, and the scissors assembly performs / stops cutting the thread according to the second signal.

[0012] It is understood that this application, by setting a sensor assembly including a first transmitter, a second transmitter, and a receiver, with the first transmitter and the second transmitter respectively positioned on both sides of the scissor assembly, allows the fabric to move from the first end to the second end of the needle plate. When the front end of the fabric passes the second transmitter, the second transmitter and receiver work together to generate a first signal. When the rear end of the fabric passes the receiver, the first transmitter and receiver work together to generate a second signal. Thus, by using the two transmitters to detect whether there is fabric when the front end and the rear end of the fabric pass by, the cutting operation at the front and rear ends of the fabric can be controlled more precisely, preventing the problem of accidental fabric cutting.

[0013] In one embodiment, the receiver detects the thickness of the rear end of the fabric between itself and the first transmitter as h. As the rear end moves toward the second end, h gradually decreases. The preset thickness of the receiver in cooperation with the first transmitter is h1. When h ≤ h1, the receiver generates the second signal, and the scissors assembly cuts the thread according to the second signal.

[0014] It is understandable that by setting a first transmitter and receiver to detect the thickness of the fabric's rear end, and since the detection lines of the first transmitter and receiver are set at an angle relative to the fabric, as the rear end of the fabric moves towards the second end, there is still a certain thickness of fabric between the first transmitter and receiver when the rear end moves to the scissor assembly. By presetting the fabric thickness value and comparing the fabric thickness detected between the first transmitter and receiver with the preset value, a second signal is emitted based on the detection result. This allows for a more accurate determination of the fabric's position and effectively avoids the problem of the anti-accidental fabric cutting control device accidentally cutting the fabric when cutting the thread at the rear end of the fabric.

[0015] In one embodiment, the anti-accidental fabric cutting control device further includes an electronic control system, wherein the first transmitter is configured as a first infrared transmitter, the receiver is configured as an infrared receiver, and the infrared receiver is electrically connected to the electronic control system.

[0016] In one embodiment, the infrared receiver converts the light emitted by the first infrared emitter into a voltage V. h The electronic control system is set with a voltage threshold V1. When the fabric thickness is h1, V... h =V1, as the rear end of the fabric moves towards the second end, h gradually decreases, V h Simultaneous decrease, when h≤h1, V h If ≤V1, the infrared receiver generates a second signal, and the electronic control system controls the scissor assembly to cut the wire according to the second signal.

[0017] In one embodiment, the receiver detects the thickness of the front end of the fabric between itself and the second transmitter as d, and the preset thickness of the receiver and the second transmitter is d1. When d≥d1, the receiver generates the first signal, and the scissors assembly stops cutting the thread according to the first signal.

[0018] Understandably, by setting up a second transmitter and receiver, when the front end of the fabric blocks the receiver, a second signal is emitted based on the preset fabric thickness value and the fabric thickness detected by the second transmitter and receiver is compared with the preset value. This allows for a more accurate determination of the fabric's position, thereby effectively preventing the fabric cutting control device from accidentally cutting the fabric when cutting the front end of the fabric.

[0019] In one embodiment, the anti-accidental fabric cutting control device further includes an electronic control system, the second transmitter is configured as a second infrared transmitter, the receiver is configured as an infrared receiver, and the infrared receiver is electrically connected to the electronic control system;

[0020] The infrared receiver converts the light emitted by the second infrared emitter into a voltage V. d The electronic control system is set to a voltage threshold V2. When the fabric thickness is d1, V... d =V2, as the front end of the fabric moves to the receiver, when d≥d1, V d ≥V2, the receiver generates the first signal, and the electronic control system controls the scissor assembly to cut the wire according to the first signal.

[0021] In one embodiment, when the front end approaches the scissor assembly, the second transmitter is activated and the first transmitter is deactivated. After a preset time, the second transmitter is deactivated and the first transmitter is activated.

[0022] In one embodiment, the scissor assembly includes a movable blade and a fixed blade. The movable blade is oscillatingly disposed on one side of the needle plate and is capable of oscillating toward the needle plate. The fixed blade is disposed on the needle plate, and the movable blade is capable of engaging with the fixed blade to perform a thread-cutting action.

[0023] In one embodiment, the anti-accidental fabric cutting control device further includes a sensor disposed on the needle plate and located near the first end of the first transmitter. When the sensor detects fabric, it generates an indication signal, and the scissor assembly cuts the thread according to the indication signal.

[0024] This application also provides the following technical solutions:

[0025] A sewing machine includes a thread-cutting control device for preventing accidental fabric cutting as described in any of the above embodiments.

[0026] Compared with existing technologies, the fabric cutting control device for preventing accidental fabric cutting uses a sensor assembly that includes a first transmitter, a second transmitter, and a receiver. The first and second transmitters are respectively positioned on opposite sides of the scissor assembly. When the fabric moves from the first end to the second end of the needle plate, the second transmitter and receiver generate a first signal when the front end of the fabric passes the second transmitter, and a second signal is generated when the rear end of the fabric passes the receiver. Thus, the two transmitters detect whether there is fabric present when the front and rear ends of the fabric pass by, enabling more precise control of the cutting operation at the front and rear ends of the fabric and preventing accidental fabric cutting. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of the thread-cutting control device for preventing accidental fabric cutting in a sewing machine provided in this application.

[0029] Figure 2 For this application Figure 1 Enlarged view of point A in the middle.

[0030] Figure 3This is a schematic diagram of the thread-cutting control device for preventing accidental fabric cutting provided in this application.

[0031] Figure 4 For this application Figure 3 Enlarged view of point B in the middle.

[0032] The component labels are as follows:

[0033] 100. Thread cutting control device to prevent accidental fabric cutting; 10. Needle plate; 11. First end; 12. Second end; 20. Scissors assembly; 21. Moving blade; 22. Fixed blade; 30. Sensor assembly; 31. First transmitter; 32. Second transmitter; 33. Receiver; 40. Sensor;

[0034] 200. Sewing machine; 201. Fabric; 202. Front end; 203. Back end. Detailed Implementation

[0035] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0036] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application's specification are for illustrative purposes only and do not represent the only possible implementation.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0040] Please see Figures 1 to 4 This application provides a thread-cutting control device 100 for preventing accidental fabric cutting. The thread-cutting control device 100 is installed on a sewing machine 200 and is used to cut the thread whips at the front end 202 and the rear end 203 of the fabric 201 after the fabric 201 is sewn.

[0041] Specifically, the anti-accidental fabric cutting control device 100 includes a needle plate 10, a scissor assembly 20, and a sensor assembly 30. The needle plate 10 has a first end 11 and a second end 12, and is used to allow the fabric 201 to move along it from the first end 11 to the second end 12. The scissor assembly 20 is disposed near the needle plate 10 and is used to cut the fabric 201. The sensor assembly 30 includes a first transmitter 31, a second transmitter 32, and a receiver 33. The receiver 33 is disposed on the needle plate 10, and the first transmitter 31 and the second transmitter 32 are disposed above the needle plate 10, with the first transmitter 31 disposed on the scissor assembly 20. On the side near the second end 12, the second transmitter 32 and receiver 33 are disposed on the side of the scissor assembly 20 near the first end 11. Both the first transmitter 31 and the second transmitter 32 are positioned facing the receiver 33. The fabric 201 has a front end 202 and a rear end 203. When the front end 202 moves to the receiver 33, the receiver 33 and the second transmitter 32 cooperate to generate a first signal, and the scissor assembly 20 performs / stops cutting the thread according to the first signal. When the rear end 203 moves to the receiver 33, the receiver 33 and the first transmitter 31 cooperate to generate a second signal, and the scissor assembly 20 performs / stops cutting the thread according to the second signal. It should be noted that the overall control process of the thread-cutting control device 100 for preventing accidental fabric cutting is as follows: after the front end 202 of the fabric 201 moves to the receiver 33, the scissor assembly 20 stops cutting the thread. When the rear end 203 of the fabric 201 moves to the receiver 33 and moves away from the receiver 33, the scissor assembly 20 starts cutting the thread when the thread-cutting requirement is met.

[0042] In existing technologies, to prevent accidental fabric cuts due to errors or operational mistakes during fabric trimming, an anti-accidental fabric cut device is required. Existing anti-accidental fabric cut devices typically consist of a transmitter and receiver positioned at the point where the fabric is about to contact the scissors. When the fabric approaches the scissors, the receiver detects the fabric and sends a signal, causing the scissors to stop cutting, thus preventing accidental fabric cuts. However, this structure is ineffective in preventing accidental fabric cuts when trimming at the rear end of the fabric. Therefore, alternative structures are needed to control accidental fabric cuts at the rear end. If a transmitter and receiver are also placed on the opposite side, the receiver's placement may interfere with other structures, making installation inconvenient. Furthermore, placing the sensor there means that trimming can only occur when the fabric has moved to a point where it no longer obstructs the receiver, resulting in residual fabric and poor trimming effectiveness. This application uses a sensor assembly 30 comprising a first transmitter 31, a second transmitter 32, and a receiver 33. The first transmitter 31 and the second transmitter 32 are respectively positioned on both sides of the scissor assembly 20. When the fabric 201 moves along the first end 11 to the second end 12 of the needle plate 10, when the front end 202 of the fabric 201 passes the second transmitter 32, the second transmitter 32 and the receiver 33 cooperate to generate a first signal. When the rear end 203 of the fabric 201 passes the receiver 33, the first transmitter 31 and the receiver 33 cooperate to generate a second signal. Thus, by using two transmitters to detect whether the fabric 201 is present when the front end 202 and the rear end 203 of the fabric 201 pass by, the cutting operation of the front end 202 and the rear end 203 of the fabric 201 can be more accurately controlled, preventing the problem of accidental fabric cutting. In addition, since this application only sets a receiver 33 located near the first end 11 of the scissor assembly 20, it will not interfere with the position of other structures and can control the timing of cutting, thereby avoiding the problem of residual cutting thread.

[0043] like Figures 2 to 4 As shown, the scissor assembly 20 includes a movable blade 21 and a fixed blade 22. The movable blade 21 is oscillatingly disposed on one side of the needle plate 10 and can swing toward the needle plate 10. The fixed blade 22 is disposed on the needle plate 10, and the movable blade 21 can engage with the fixed blade 22 to perform a thread cutting action.

[0044] In this embodiment, the receiver 33 is located in the middle of the fixed blade 22, the first transmitter 31 is located on the side of the movable blade 21 near the second end 12, and the second transmitter 32 and the receiver 33 are located on the side of the movable blade 21 near the first end 11.

[0045] In one embodiment, the receiver 33 detects the thickness of the rear end 203 of the fabric 201 between itself and the first transmitter 31 as h. As the rear end 203 moves toward the second end 12, h gradually decreases. The preset thickness of the receiver 33 and the first transmitter 31 is h1. When h ≤ h1, it is determined that the rear end 203 leaves the receiver 33. The receiver 33 generates a second signal, and the scissor assembly 20 cuts the thread according to the second signal. Thus, by setting the first transmitter 31 and receiver 33 to detect the thickness of the rear end 203 of the fabric 201, since the detection lines of the first transmitter 31 and receiver 33 are set at an angle relative to the fabric 201, as the rear end 203 of the fabric 201 moves towards the second end 12, when the rear end 203 moves to the scissor assembly 20, there is still a certain thickness of fabric 201 between the first transmitter 31 and receiver 33. By preset the thickness value of the fabric 201 and comparing the thickness of the fabric 201 detected between the first transmitter 31 and receiver 33 with the preset value, a second signal is emitted according to the detection result, which can more accurately determine the position of the fabric 201 and effectively avoid the problem of accidental fabric cutting when the anti-accidental fabric cutting control device 100 cuts the fabric at the rear end 203 of the fabric 201.

[0046] Furthermore, within a certain range, the greater the horizontal distance between the first transmitter 31 and the receiver 33, the slower the thickness change of the fabric 201 between the first transmitter 31 and the receiver 33, and the more precise the control of the position of the fabric 201. Therefore, the horizontal distance between the first transmitter 31 and the receiver 33 should be appropriately increased to make the detection results more accurate and facilitate the control of the scissor assembly 20 to cut the thread appropriately.

[0047] In one embodiment, the anti-accidental fabric cutting control device 100 further includes an electronic control system, with the first transmitter 31 configured as a first infrared transmitter and the receiver 33 configured as an infrared receiver, and the infrared receiver electrically connected to the electronic control system. In other embodiments, structures such as a capacitive sensor 40 and an ultrasonic sensor 40 can also be used to detect the thickness of the fabric 201.

[0048] In one embodiment, the infrared receiver converts the light emitted by the first infrared emitter into a voltage V. h The electrical control system is set to a voltage threshold V1. When the thickness of fabric 201 is h1, V... h =V1, as the rear end 203 of the fabric 201 moves towards the second end 12, h gradually decreases, V h Simultaneous decrease, when h≤h1, V hWhen the voltage threshold is ≤V1, the infrared receiver generates a second signal, and the electronic control system controls the scissor assembly 20 to cut the fabric. Besides setting the voltage threshold, in other embodiments, the infrared sensor 40 and infrared receiver can preset the fabric 201 thickness and accurately judge changes in fabric 201 thickness by adjusting the infrared transmitter's power board and changing the gain of the receiver 33 (i.e., adjusting the amplification factor of the receiving amplifier circuit). This allows for precise control of the scissor assembly 20's cutting action, preventing accidental fabric cutting. Here, the electronic control system adjusts the sensitivity of detecting when fabric 201 leaves the infrared receiver by adjusting the voltage threshold V1. When V1 is high, the electronic control system can only determine that fabric 201 has left the infrared receiver after the rear end 203 has moved a considerable distance, thus reducing the sensitivity of detecting when the rear end 203 leaves the infrared receiver. When V1 is low, the sensitivity of detecting when the rear end 203 leaves the infrared receiver is increased.

[0049] In one embodiment, the receiver 33 detects the thickness d of the front end 202 of the fabric 201 between itself and the second transmitter 32. The preset thickness of the cooperation between the receiver 33 and the second transmitter 32 is d1. When d ≥ d1, it is determined that the front end 202 is located on the receiver 33, and the receiver 33 generates a first signal. The scissor assembly 20 stops cutting the thread according to the first signal. By setting the second transmitter 32 and the receiver 33, when the front end 202 of the fabric 201 blocks the receiver 33, by setting a preset fabric 201 thickness value and comparing the detected fabric 201 thickness between the second transmitter 32 and the receiver 33 with the preset value, a second signal is emitted according to the detection result. This allows for a more accurate determination of the position of the fabric 201, thereby effectively avoiding the problem of accidental fabric cutting when the thread-cutting control device 100 cuts the thread at the front end 202 of the fabric 201.

[0050] In one embodiment, the second transmitter 32 of the anti-accidental fabric cutting control device 100 is configured as a second infrared transmitter, and the receiver 33 is configured as an infrared receiver, and the infrared receiver is electrically connected to the electronic control system; the infrared receiver converts the light emitted by the second infrared transmitter into a voltage V. d The electrical control system is set to a voltage threshold V2. When the thickness of fabric 201 is d1, V... d =V2, as the front end 202 of the fabric 201 moves to the receiver 33, when d≥d1, V dWhen V2 is greater than or equal to 2, receiver 33 generates a first signal, and the electronic control system controls the scissor assembly 20 to cut the thread based on the first signal. Here, the electronic control system can adjust the sensitivity of the infrared receiver in recognizing the fabric 201 by adjusting the voltage threshold V2. When V2 is increased, the electronic control system can determine that the front end 202 has moved to the infrared receiver when it is far away, thus increasing the sensitivity of the front end 202 reaching the infrared receiver. When V1 is decreased, the recognition sensitivity of the front end 202 when it blocks the infrared receiver is decreased. Therefore, by increasing the sensitivity of the infrared receiver, the fabric 201 can be recognized earlier, allowing more control time for the front end 202, making it less likely to cut the fabric when sewing irregularly shaped pieces.

[0051] It should be noted that the structure and arrangement of the second transmitter 32 can refer to that of the first transmitter 31. Furthermore, since the second transmitter 32 and the first transmitter 31 share a single receiver 33 in this embodiment, they should be configured with the same structure. In other embodiments, the receiver 33 can also be configured as two parallel receiving units, in which case one transmitter corresponds to one receiving unit, and each transmitter and its corresponding receiving unit need only be compatible; it is not necessary to configure the two receivers 33 with the same structure.

[0052] Furthermore, when the front end 202 approaches the scissor assembly 20, the second transmitter 32 is activated and the first transmitter 31 is deactivated. After a preset time, the second transmitter 32 deactivates and the first transmitter 31 activates. Here, the preset time is the time required for the fabric 201 to move from the front end 202 to the rear end 203, which can be set according to actual usage requirements.

[0053] In one embodiment, the anti-accidental fabric cutting control device 100 further includes a sensor 40, which is disposed on the needle plate 10 and located near the first end 11 of the first transmitter 31. When the sensor 40 detects the fabric 201, it generates an indication signal, and the scissor assembly 20 cuts the thread according to the indication signal. Here, the sensor 40 can be configured as a photoelectric sensor 40, a micro-motion sensor 40, or an ultrasonic sensor 40, etc.

[0054] This application also provides the following technical solutions:

[0055] A sewing machine 200 includes a thread-cutting control device 100 for preventing accidental fabric cutting as described in any of the above embodiments.

[0056] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the patent protection scope of this application should be determined by the appended claims.

Claims

1. A thread-cutting control device to prevent accidental fabric cutting, for use in a sewing machine (200), characterized in that, The thread-cutting control device (100) for preventing accidental fabric cutting includes: A needle plate (10) having a first end (11) and a second end (12) for moving fabric (201) along it from the first end (11) to the second end (12); A scissor assembly (20) is disposed near the needle plate (10) and is used to cut the threads of the fabric (201); The sensor assembly (30) includes a first transmitter (31), a second transmitter (32), and a receiver (33). The receiver (33) is disposed on the needle plate (10). The first transmitter (31) and the second transmitter (32) are disposed above the needle plate (10). The first transmitter (31) is disposed on the side of the scissor assembly (20) near the second end (12). The second transmitter (32) and the receiver (33) are disposed on the side of the scissor assembly (20) near the first end (11). The first transmitter (31) and the second transmitter (32) are both disposed facing the receiver (33). The fabric (201) has a front end (202) and a rear end (203). When the front end (202) moves to the receiver (33), the receiver (33) cooperates with the second transmitter (32) to generate a first signal, and the scissor assembly (20) performs / stops cutting the thread according to the first signal. When the rear end (203) moves to the receiver (33), the receiver (33) cooperates with the first transmitter (31) to generate a second signal, and the scissor assembly (20) performs / stops cutting the thread according to the second signal.

2. The thread-cutting control device for preventing accidental fabric cutting according to claim 1, characterized in that, The receiver (33) detects the thickness of the rear end (203) of the fabric (201) between itself and the first transmitter (31) as h. As the rear end (203) moves toward the second end (12), h gradually decreases. The preset thickness of the receiver (33) cooperating with the first transmitter (31) is h1. When h≤h1, the receiver (33) generates the second signal, and the scissor assembly (20) performs thread cutting according to the second signal.

3. The thread-cutting control device for preventing accidental fabric cutting according to claim 2, characterized in that, The anti-accidental fabric cutting control device (100) further includes an electronic control system, wherein the first transmitter (31) is configured as a first infrared transmitter, the receiver (33) is configured as an infrared receiver, and the infrared receiver is electrically connected to the electronic control system.

4. The thread-cutting control device for preventing accidental fabric cutting according to claim 3, characterized in that, The infrared receiver converts the light emitted by the first infrared emitter into a voltage V. h The electronic control system is set with a voltage threshold V1. When the thickness of the fabric (201) is h1, V1 is set to V1. h =V1, as the rear end (203) of the fabric (201) moves towards the second end (12), h gradually decreases, V h Simultaneous decrease, when h≤h1, V h ≤V1, the infrared receiver generates a second signal, and the electronic control system controls the scissor assembly (20) to cut the wire according to the second signal.

5. The thread-cutting control device for preventing accidental fabric cutting according to claim 1, characterized in that, The receiver (33) detects the thickness of the front end (202) of the fabric (201) between itself and the second transmitter (32) as d. The preset thickness of the receiver (33) and the second transmitter (32) is d1. When d≥d1, the receiver (33) generates the first signal, and the scissor assembly (20) stops cutting the thread according to the first signal.

6. The thread-cutting control device for preventing accidental fabric cutting according to claim 5, characterized in that, The anti-accidental fabric cutting control device (100) further includes an electronic control system, the second transmitter (32) is configured as a second infrared transmitter, the receiver (33) is configured as an infrared receiver, and the infrared receiver is electrically connected to the electronic control system; The infrared receiver converts the light emitted by the second infrared emitter into a voltage V. d The electronic control system is set with a voltage threshold V2. When the thickness of the fabric (201) is d1, V... d =V2, as the front end (202) of the fabric (201) moves to the receiver (33), when d≥d1, V d ≥V2, the receiver (33) generates the first signal, and the electronic control system controls the scissor assembly (20) to cut the wire according to the first signal.

7. The thread-cutting control device for preventing accidental fabric cutting according to claim 1, characterized in that, When the front end (202) approaches the scissor assembly (20), the second transmitter (32) turns on and the first transmitter (31) turns off. After a preset time, the second transmitter (32) turns off and the first transmitter (31) turns on.

8. The thread-cutting control device for preventing accidental fabric cutting according to claim 1, characterized in that, The scissor assembly (20) includes a movable blade (21) and a fixed blade (22). The movable blade (21) is oscillatingly disposed on one side of the needle plate (10) and can swing toward the needle plate (10). The fixed blade (22) is disposed on the needle plate (10). The movable blade (21) can engage with the fixed blade (22) to perform a thread cutting action.

9. The thread-cutting control device for preventing accidental fabric cutting according to claim 1, characterized in that, The anti-accidental fabric cutting control device (100) also includes a sensor (40), which is disposed on the needle plate (10) and located near the first end (11) of the first transmitter (31). When the sensor (40) detects the fabric (201), it generates an indication signal, and the scissor assembly (20) cuts the thread according to the indication signal.

10. A sewing machine, characterized in that, Includes the thread-cutting control device (100) for preventing accidental fabric cutting as described in any one of claims 1-9.

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