Thread trimming mechanism and sewing machine

Abstract

The embodiment of the utility model discloses a thread trimming mechanism and a sewing machine, and belongs to the field of sewing device equipment.The thread trimming mechanism comprises a driving assembly, a transmission assembly and a thread trimming assembly; the driving assembly comprises a cam, and the cam is rotationally arranged around a first rotating axis; the transmission assembly comprises a thread trimming crank and a connecting rod, the first end of the thread trimming crank slides along the cam surface of the cam relative to the cam, the connecting rod rotates around a second rotating axis relative to the second end of the thread trimming crank, and the first rotating axis intersects with the second rotating axis; the thread trimming assembly comprises a movable cutter and a fixed cutter, and the movable cutter is arranged at the end, deviating from the thread trimming crank, of the connecting rod; when the cam rotates, the thread trimming crank drives the movable cutter to rotate around the second rotating axis relative to the fixed cutter through the connecting rod so as to change the angle between the movable cutter and the fixed cutter. According to the thread trimming mechanism and the sewing machine, the thread trimming stroke angle can be adjusted, the thread trimming efficiency is high, and the structure is simple.

Description

Technical Field

[0001] The present application relates to the technical field of sewing devices and equipment, and in particular to a thread trimming mechanism and a sewing machine. Background Art

[0002] The thread trimming mechanism of the overlock sewing machine is a key component of the overlock sewing machine. During a sewing cycle, the overlock sewing machine has two main thread trimming actions. One is to trim the thread after sewing begins to cut off the excess thread at the front, and the other is to trim the thread after sewing is completed to cut off the excess thread formed during the sewing process.

[0003] At present, the automatic thread trimming mechanism of the existing overlock sewing machine includes a movable knife, a fixed knife, a sensor and a drive mechanism. Among them, the fixed knife is fixed on the knife seat, and the movable knife is rotatably set on the knife seat. The drive mechanism provides power for the rotation of the movable knife, so that the movable knife and the fixed knife cooperate to achieve thread trimming.

[0004] However, the thread trimming stroke angle of the overlock sewing machine in the prior art is not easy to adjust, so that the thread trimming stroke angle and thread trimming efficiency are difficult to improve. Utility Model Content

[0005] The present application provides a thread trimming mechanism and a sewing machine, which can adjust the thread trimming stroke angle, have high thread trimming efficiency and simple structure.

[0006] In a first aspect, the present application provides a thread trimming mechanism, comprising: a drive assembly, a transmission assembly, and a thread trimming assembly; the drive assembly comprising a cam, the cam being rotatably disposed about a first rotation axis; the transmission assembly comprising a thread trimming crank and a connecting rod, the first end of the thread trimming crank being slidably disposed relative to the cam along a cam surface of the cam, and the connecting rod being rotatable relative to a second end of the thread trimming crank about a second rotation axis, wherein the first rotation axis and the second rotation axis intersect; the thread trimming assembly comprising a movable knife and a fixed knife, the movable knife being disposed at an end of the connecting rod facing away from the thread trimming crank;

[0007] When the cam rotates, the thread trimmer crank drives the movable knife to rotate relative to the fixed knife around the second rotation axis through the connecting rod, so as to change the angle between the movable knife and the fixed knife.

[0008] As in the above-mentioned thread trimming mechanism, the cam surface includes a first arc portion and a second arc portion protruding relative to the center of the cam, and the curvature of the profile of the first arc portion is greater than the curvature of the profile of the second arc portion;

[0009] The first arc portion and the second arc portion are connected to form a recessed portion at the connection between the first arc portion and the second arc portion.

[0010] As in the above-mentioned thread trimming mechanism, the cam surface also includes a third arc portion and a straight portion. The third arc portion is protruding relative to the center of the cam, and the profile curvature of the third arc portion is smaller than the profile curvature of the second arc portion; the first arc portion, the second arc portion, the third arc portion and the straight portion are connected end to end in sequence around the first rotation axis.

[0011] The thread trimming mechanism as described above further comprises a telescopic member, which is telescopically arranged at the first end of the thread trimming crank in a first direction, wherein the first direction is perpendicular to the extending direction of the first rotation axis.

[0012] As in the above-mentioned thread trimming mechanism, the telescopic part includes a fixed part and a movable part. The movable part is cylindrical, and the movable part is partially sleeved on the fixed part and moves in a first direction relative to the fixed part; the end of the fixed part away from the movable part is connected to the thread trimming crank, and a pressure adjusting screw is provided on the fixed part.

[0013] The thread trimming mechanism as described above further includes an elastic member, which is located inside the movable portion, and whose two ends along the first direction respectively abut against the movable portion and the pressure-adjusting screw.

[0014] As in the above-mentioned thread trimming mechanism, the transmission assembly includes a ball, which is rotatably connected to the first end of the thread trimming crank, and the thread trimming crank is in sliding contact with the cam surface of the cam through the ball.

[0015] As described above, the thread trimming mechanism further includes a controller and a detector. The driving assembly includes a motor, which is connected to the cam and configured to drive the cam to rotate around the first rotation axis. The controller is electrically connected to the motor and configured to control the direction of the motor.

[0016] As in the above-mentioned thread trimming mechanism, the motor is a stepping motor.

[0017] In a second aspect, the present application provides a sewing machine, comprising a sewing machine body and the above-mentioned thread trimming mechanism, wherein the thread trimming mechanism is fixedly arranged on the sewing machine body.

[0018] This application provides a thread trimming mechanism and sewing machine. By designing the cam surface of a cam into an irregular shape and connecting a thread trimming crank to the cam, the thread trimming crank, driven by the cam, moves to different areas of the cam surface, thereby driving the movable knife connected to the thread trimming crank to rotate to different angles relative to the fixed knife to cut the thread. Compared to traditional thread trimming mechanisms, this device can adjust the thread trimming stroke angle and has higher thread trimming efficiency.

[0019] The structure of a thread trimming mechanism and a sewing machine provided by the present application as well as the purposes and beneficial effects of other utility models thereof will be more clearly understood through the description of the preferred embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 This is a structural diagram of a thread trimming mechanism provided in an embodiment of the present application;

[0022] Figure 2 This is an exploded view of a thread trimming mechanism provided in an embodiment of the present application;

[0023] Figure 3 is a partial cross-sectional view of a sewing machine provided in an embodiment of the present application;

[0024] Figure 4 This is a schematic diagram of the connection relationship between a cam and a ball in a thread trimming mechanism provided in an embodiment of the present application;

[0025] Figure 5 This is a schematic diagram of the connection relationship between a movable knife and a fixed knife in a thread trimming mechanism provided in an embodiment of the present application;

[0026] Figure 6 It is a structural schematic diagram of a sewing machine provided in an embodiment of the present application.

[0027] Description of reference numerals:

[0028] 10-thread trimming mechanism;

[0029] 100 - drive assembly; 110 - motor; 120 - first rotation axis;

[0030] 200- transmission assembly;

[0031] 210 - cam; 211 - mounting sleeve; 212 - cam body; 2121 - first arc portion; 2122 - second arc portion; 2123 - recessed portion; 2124 - third arc portion; 2125 - straight portion;

[0032] 220-ball;

[0033] 231 - Trimming crank; 2311 - Trimming crank body; 2312 - Mounting base; 232 - Connecting rod; 234 - Pin; 250 - Second rotation axis;

[0034] 300-thread trimming assembly; 310-movable knife; 320-fixed knife; 330-cover plate; 340-suction pipe;

[0035] 400-controller; 410-detector; 411-transmitting sensor; 412-receiving sensor;

[0036] 500- telescopic part; 510- elastic part; 520- fixed part; 530- movable part; 540- pressure adjusting screw;

[0037] 600-working surface;

[0038] 20-Sewing machine. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0040] The thread trimming mechanism of an overlock sewing machine is a key component. During a sewing cycle, the machine performs two primary thread trimming actions: one at the beginning of sewing to remove excess thread at the front, and the other at the end of sewing to cut off any excess thread formed during the sewing process. Currently, the automatic thread trimming mechanism of an overlock sewing machine consists of a movable blade, a fixed blade, a sensor, and a drive mechanism. The fixed blade is fixed to a blade holder, while the movable blade rotates on the blade holder. The drive mechanism powers the movable blade, enabling the movable and fixed blades to coordinate and trim the thread.

[0041] However, the thread trimming stroke angle of the overlock sewing machine in the prior art is not easy to adjust, so that the thread trimming stroke angle and thread trimming efficiency are difficult to improve.

[0042] To this end, the present application provides a thread trimming mechanism. By designing the cam surface of a cam into an irregular shape and connecting a thread trimming crank to the cam, the thread trimming crank is driven by the cam to move to different areas of the cam surface, thereby driving the movable knife connected to the thread trimming crank to rotate to different angles relative to the fixed knife to cut the suture. Compared with traditional thread trimming mechanisms, this device can adjust the thread trimming stroke angle and has higher thread trimming efficiency.

[0043] A thread trimming mechanism in this embodiment will be further described below.

[0044] Figure 1 This is a structural diagram of a thread trimming mechanism provided in an embodiment of the present application; Figure 2 This is an exploded view of a thread trimming mechanism provided in an embodiment of the present application; Figure 3 is a partial cross-sectional view of a sewing machine provided in an embodiment of the present application; Figure 4 This is a schematic diagram of the connection relationship between a cam and a ball in a thread trimming mechanism provided in an embodiment of the present application; Figure 5 This is a schematic diagram of the connection relationship between a movable knife and a fixed knife in a thread trimming mechanism provided in an embodiment of the present application.

[0045] In this embodiment, reference Figure 1 As shown, an embodiment of the present application provides a thread trimming mechanism 10 , which includes a driving assembly 100 , a transmission assembly 200 and a thread trimming assembly 300 .

[0046] The driving assembly 100 is fixedly mounted on the housing of the sewing machine 20 , and the transmission assembly 200 is connected to the driving assembly 100 so that the transmission assembly 200 rotates under the drive of the driving assembly 100 .

[0047] Specifically, the transmission assembly 200 includes a cam 210 , and the cam 210 is rotatably disposed around the first rotation axis 120 .

[0048] The transmission assembly includes a trimmer crank 231 and a connecting rod 232. The first end of the trimmer crank 231 is slidably arranged along the cam surface of the cam 210 relative to the cam 210, and the connecting rod 232 rotates around the second rotation axis 250 relative to the second end of the trimmer crank 231, wherein the first rotation axis 120 and the second rotation axis 250 intersect.

[0049] The thread trimming assembly 300 includes a movable knife 310 and a fixed knife 320 . The movable knife 310 is disposed at the end of the connecting rod 232 away from the thread trimming crank 231 .

[0050] When the cam 210 rotates, the thread trimmer crank 231 drives the movable knife 310 to rotate relative to the fixed knife 320 around the second rotation axis 250 through the connecting rod 232 to change the angle between the movable knife 310 and the fixed knife 320.

[0051] Specifically, the movement directions of the trimmer crank 231 and the cam 210 are as follows: Figure 3 Indicated by the arrow.

[0052] In this embodiment, the cam 210 includes a mounting sleeve 211 and a cam body 212 . The mounting sleeve 211 is configured to fix the cam 210 on the first rotation axis 120 , and the cam body 212 is connected to the thread trimmer crank 231 .

[0053] In this embodiment, reference Figure 2 As shown, a first mounting through hole and a second mounting through hole are also provided on the mounting base 2312, wherein the telescopic member 500 is arranged in the first mounting through hole; a bolt is passed through the second mounting through hole and abuts against the outer wall of the telescopic member 500 to connect the trimmer crank 231 and the telescopic member 500.

[0054] In this embodiment, a "U"-shaped groove is provided on one end of the thread trimmer crank body 2311 close to the connecting rod 232, and a mounting through hole is provided on the connecting rod 232. The pin 234 passes through the "U"-shaped groove and the mounting through hole to connect the thread trimmer crank 231 and the connecting rod 232 together, and the pin 234 can slide inside the "U"-shaped groove.

[0055] In this implementation, reference Figure 2 As shown, the cam 210 is provided with a mounting sleeve 211 and a cam body 212. The cam body 212 is provided with a through hole. The cam 210 is mounted on the output shaft of the motor 110, i.e., the first rotation axis 120, through the through hole and the mounting sleeve 211. The mounting sleeve 211 is provided with an internal threaded hole, and a screw is inserted into the internal threaded hole to fix the cam 210 to the output shaft of the motor 110. Specifically, the cam body 212 is also provided with a weight-reducing hole for reducing the weight of the cam 210 to improve transmission efficiency.

[0056] In some possible implementations, the cam surface includes a first arc portion 2121 and a second arc portion 2122 protruding relative to the center of the cam 210 , and the profile curvature of the first arc portion 2121 is greater than the profile curvature of the second arc portion 2122 .

[0057] The first arc portion 2121 and the second arc portion 2122 are connected to form a recessed portion 2123 at the connection between the first arc portion 2121 and the second arc portion 2122 .

[0058] In this embodiment, reference Figure 4 As shown, the first arc portion 2121 is composed of arcs with the same curvature radius, and the second arc portion 2122 is composed of arcs with different curvature radii.

[0059] When the thread trimming crank 231 moves along the first arc portion 2121, the thread trimming crank 231 moves at a constant speed; when the thread trimming crank 231 moves along the second arc portion 2122, the thread trimming crank 231 moves at a variable speed; when the thread trimming crank 231 moves from the first arc portion 2121 to the recessed position 2123, the thread trimming crank 231 decelerates, and when leaving the recessed position 2123, the thread trimming crank 231 accelerates.

[0060] Among them, the purpose of setting the recessed position 2123 between the first arc portion 2121 and the second arc portion 2122 is to play a role in shock absorption and buffering, and to allow the trimming crank 231 to stay in the recessed position 2123, so as to control the timing of the trimming action to avoid affecting the trimming quality.

[0061] Among them, the starting angle of thread trimming is associated with the rotation angle of the output shaft of the motor 110. When operating, the staff can set the initial angle and the ending angle based on the actual situation to ensure that the thread trimming mechanism can cut the suture.

[0062] In this embodiment, reference Figure 4 As shown, the thread cutting stroke angle is α, and the angle maintained at β when the movable knife 310 is at its lowest position is 60°-70°. For example, the thread cutting stroke angle α can be selected from 60°, 70° or any value between 60°-70°. In this embodiment, the thread cutting stroke angle α is selected as 61°, and the range of the angle β maintained when the movable knife 310 is at its lowest position is 20°-30°. For example, the angle β maintained when the movable knife 310 is at its lowest position can be 20°, 30°, or any value between 20°-30°. In this embodiment, the angle β maintained when the movable knife 310 is at its lowest position is selected as 28°.

[0063] In some possible implementations, the cam surface further includes a third arc portion 2124 and a straight portion 2125 . The third arc portion 2124 is protruding relative to the center of the cam 210 , and the profile curvature of the third arc portion 2124 is smaller than the profile curvature of the second arc portion 2122 .

[0064] The first arc portion 2121 , the second arc portion 2122 , the third arc portion 2124 and the straight portion 2125 are sequentially connected end to end around the first rotation axis 120 .

[0065] In this embodiment, the cam surface of the cam 210 is designed to be connected in sections of different shapes, so that different movement speeds and accelerations can be achieved, thereby ensuring the accuracy and reliability of the thread trimming action.

[0066] In some possible implementations, a telescopic member 500 is further included. The telescopic member 500 is telescopically disposed at the first end of the thread trimmer crank 231 along a first direction, where the first direction is perpendicular to the extension direction of the first rotation axis 120 .

[0067] In this embodiment, reference Figure 1 and Figure 2 As shown, the telescopic member 500 is arranged above the transmission assembly 200, so that the transmission assembly 200 can drive the telescopic member 500 to extend and retract in the vertical direction while moving, which can serve the purpose of buffering, making the wire cutting process more stable and ensuring the smoothness of wire cutting.

[0068] In some possible implementations, the telescopic member 500 includes a fixed portion 520 and a movable portion 530 . The movable portion 530 is cylindrical. The movable portion 530 is partially sleeved on the fixed portion 520 and moves relative to the fixed portion 520 along a first direction.

[0069] The end of the fixed portion 520 facing away from the movable portion 530 is connected to the thread trimmer crank 231 .

[0070] Among them, as an optional embodiment, the movable part 530 and the fixed part 520 are connecting rods with hollow cavities, and the diameters of the movable part 530 and the fixed part 520 are different, so that the movable part 530 can be installed inside the fixed part 520, and the movable part 530 can be extended and retracted in the vertical direction.

[0071] In some possible implementations, an elastic member 510 is further included. The elastic member 510 is located inside the movable portion 530 , and two ends of the elastic member 510 along the first direction respectively abut against the movable portion 530 and the fixed portion 520 .

[0072] In this embodiment, reference Figure 2 As shown, a pressure-adjusting screw 540 is further provided above the fixed portion 520, and the pressure-adjusting screw 540 is screwed into the threaded hole inside the fixed portion 520. In this way, by changing the screwing depth of the pressure-adjusting screw 540, the force applied to the movable portion 530 is adjusted, thereby changing the thread cutting force and improving the stability of the thread cutting process.

[0073] The movable portion 530 is internally provided with a mounting boss, one end of the elastic member 510 abuts against the mounting boss, and the other end abuts against the pressure-adjusting screw 540. Specifically, both the mounting boss and the pressure-adjusting screw 540 are provided with a slot for fixing the elastic member 510 to prevent it from moving or deforming during the expansion and contraction process.

[0074] The fixing portion 520 is provided with a mounting bracket, the mounting bracket has a mounting hole inside, and a bolt is passed through the mounting hole to fix the fixing portion 520 to the housing.

[0075] In this embodiment, a locking member (not shown) is provided on the inner sidewall of the fixed portion 520 to secure the elastic member 510 after adjusting the tension to a suitable value, thereby preventing the elastic member 510 from loosening or shifting. For example, the locking member can be a spring pin provided on the inner sidewall of the fixed portion 520 and abutting against the outer sidewall of the movable portion 530.

[0076] Specifically, the number of spring pins is at least two, and the spring pins are arranged at both ends of the fixed part 520 in the radial direction. When the movable part 530 moves in the vertical direction, the spring pins retract under the action of pressure. At this time, the spring pins are in an unlocked state; when the movable part 530 does not move in the vertical direction, at this time, the spring pins are in a locked state, and the position of the elastic member 510 is fixed.

[0077] In some possible implementations, the transmission assembly 200 includes a ball 220 , which is rotatably connected to a first end of a trimmer crank 231 . The trimmer crank 231 is in sliding contact with a cam surface of the cam 210 via the ball 220 .

[0078] In this embodiment, in order to improve the wear resistance of the ball 220 and extend the service life of the ball 220, the material of the ball 220 is selected to be hardened steel.

[0079] As an optional embodiment, the ball bearing 220 is disposed below the trimming crank 231. This arrangement is intended to provide vertical support and enhance the overall stability of the trimming mechanism 10. This helps maintain consistent performance during the trimming process.

[0080] As another optional embodiment, the ball bearing 220 is arranged on the side of the trimming crank 231. The purpose of such arrangement is to provide lateral support, enhance the overall stability of the trimming mechanism 10, and avoid deviation or instability caused by lateral force. In this embodiment, the ball bearing 220 is arranged on the side of the trimming crank 231, such as Figures 1 to 3 shown.

[0081] In some possible embodiments, a controller 400 and a detector 410 are further included, the drive assembly 100 includes a motor 110, the motor 110 is connected to the cam 210, and the motor 110 is configured to drive the cam 210 to rotate around the first rotation axis 120; the controller 400 is electrically connected to the motor 110, and the controller 400 is configured to control the direction of the motor 110.

[0082] In this embodiment, reference Figure 3 As shown, the detector 410 includes a transmitting sensor 411 and a receiving sensor 412 . The transmitting sensor 411 is disposed on the frame of the sewing machine, and the receiving sensor 412 is disposed on the work surface 600 .

[0083] Specifically, when the sewing material is placed on the work surface 600, the receiving sensor 412 receives a signal from the transmitting sensor 411, and the controller 400 sends a control signal according to the signal received by the receiving sensor 412 to control the presser foot mechanism to lift its foot. When the receiving sensor 412 is covered by the sewing material, the controller 400 receives a front thread trimming signal and starts counting the number of sewing stitches. When the number of sewing stitches reaches the set number of stitches, the controller controls the motor 110 to drive the movable knife 310 to complete the thread trimming operation and continue sewing. When the sewing material leaves the receiving sensor 412, the controller 400 starts to calculate the number of rear thread trimming stitches. When the number of thread trimming stitches reaches the set value and the sewing material leaves the receiving sensor 412, the controller 400 sends an instruction and starts thread trimming.

[0084] As an optional embodiment, the transmitting sensor 411 and the receiving sensor 412 are photoelectric sensors for detecting the presence of sewing materials.

[0085] Specifically, a position sensor is provided near the movable knife 310 for detecting the position of the movable knife 310 . When the position sensor detects that the position of the movable knife 310 deviates from the set position, the controller 400 controls the motor 110 to rotate to fine-tune the position of the movable knife 310 .

[0086] In some possible implementations, the motor 110 is a stepper motor.

[0087] The stepper motor is electrically connected to the controller 400, and the controller 400 changes the rotation angle of the stepper motor by changing the pulse signal of the stepper motor (110). In this embodiment, the stepper motor generates 2400 pulse signals when it rotates one circle, and each pulse signal controls the stepper motor to rotate 0.15°.

[0088] The present embodiment provides a thread trimming mechanism. By designing the cam surface of a cam 210 into an irregular shape and connecting a thread trimming crank 231 to the cam 210, the thread trimming crank 231 is driven by the cam 210 to move to different areas of the cam surface, thereby driving the movable blade 310 connected to the thread trimming crank 231 to rotate to different angles relative to the fixed blade 320 to cut the suture. Compared to traditional thread trimming mechanisms, this device can adjust the thread trimming stroke angle and has higher thread trimming efficiency.

[0089] The following is a further description of a sewing machine in this embodiment.

[0090] Figure 6 It is a structural schematic diagram of a sewing machine provided in an embodiment of the present application.

[0091] This embodiment further provides a sewing machine, including a sewing machine body and a thread trimming mechanism arranged on the sewing machine body, wherein the specific structure, function and working principle of the thread trimming mechanism 10 have been described in detail in the above embodiments and will not be repeated here.

[0092] In this embodiment, the motor is also connected to the presser foot mechanism, the automatic stitch length adjustment mechanism, and the differential adjustment mechanism. The purpose of this arrangement is to drive multiple mechanisms through one motor 110 to simplify the design and operation process of the sewing machine and improve work efficiency.

[0093] In this embodiment, continue to refer to Figure 5As shown, the housing of the motor 110 is provided with a mounting portion, and the motor 110 is fixedly mounted on the housing via the mounting portion. Specifically, the housing is provided with a mounting boss that matches the mounting portion, and a bolt passes through the mounting portion and screws into a threaded hole inside the mounting boss to securely connect the motor 110 to the housing.

[0094] In this embodiment, the types of the sewing machine 20 include but are not limited to an overlock sewing machine, a lockstitch sewing machine, a pattern sewing machine, and the like.

[0095] In this embodiment, reference Figure 5 As shown, the sewing machine 20 also includes a cover plate 330. Specifically, a suction pipe 340 is provided below the cover plate 330 for absorbing cut sutures and dust, keeping the work surface 600 clean, and preventing accumulation of debris from affecting sewing quality and machine performance.

[0096] The terms "first," "second," and the like in the embodiments of the present application are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate to facilitate the description of the embodiments of the present application herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions.

[0097] In the embodiments of the present application, the terms "upper", "lower", "inside", "middle", "outside", "front", "back", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily intended to better describe the present application and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to being constructed and operated in a specific orientation. Moreover, in addition to being used to indicate orientations or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present application can be understood based on the specific circumstances.

[0098] Furthermore, the terms "disposed," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean a fixed connection, a removable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediary, or an internal connection between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the embodiments of this disclosure based on the specific circumstances.

[0099] It should be noted that phrases such as "one embodiment," "an embodiment," "exemplary embodiments," and "some embodiments" in this specification may indicate embodiments that may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not.

[0100] In general, terms should be understood, at least in part, based on the context in which they are used. For example, as used herein, the term "one or more" can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense, depending at least in part on the context. Similarly, terms such as "a" and "an" can also be understood to convey either singular or plural usage, depending at least in part on the context.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A thread trimming mechanism, characterized in that: include: The driving assembly (100) includes a cam (210), wherein the cam (210) is rotatably arranged around a first rotation axis (120); A transmission assembly (200) comprises a thread trimmer crank (231) and a connecting rod (232), wherein a first end of the thread trimmer crank (231) is slidably arranged along a cam surface of the cam (210) relative to the cam (210), and the connecting rod (232) is rotated around a second rotation axis (250) relative to a second end of the thread trimmer crank (231), wherein the first rotation axis (120) and the second rotation axis (250) intersect; A thread trimming assembly (300) comprises a movable knife (310) and a fixed knife (320), wherein the movable knife (310) is arranged at the end of the connecting rod (232) away from the thread trimming crank (231); When the cam (210) rotates, the thread trimming crank (231) drives the movable knife (310) to rotate relative to the fixed knife (320) around the second rotation axis (250) via the connecting rod (232), thereby changing the angle between the movable knife (310) and the fixed knife (320).

2. The thread trimming mechanism according to claim 1, characterized in that: The cam surface comprises a first arc portion (2121) and a second arc portion (2122) protruding relative to the center of the cam (210), and the profile curvature of the first arc portion (2121) is greater than the profile curvature of the second arc portion (2122); The first arc portion (2121) and the second arc portion (2122) are connected to form a recessed portion (2123) at the connection between the first arc portion (2121) and the second arc portion (2122).

3. The thread trimming mechanism according to claim 2, characterized in that: The cam (210) surface further includes a third arc portion (2124) and a straight portion (2125), wherein the third arc portion (2124) is arranged to protrude relative to the center of the cam (210), and the profile curvature of the third arc portion (2124) is smaller than the profile curvature of the second arc portion (2122); The first arc portion (2121), the second arc portion (2122), the third arc portion (2124) and the straight portion (2125) are connected end to end in sequence around the first rotation axis (120).

4. The thread trimming mechanism according to any one of claims 1 to 3, characterized in that: It also includes a telescopic member (500), the telescopic member (500) being arranged at the first end of the thread trimmer crank (231) in a telescopic manner along a first direction, wherein the first direction is perpendicular to the extension direction of the first rotation axis (120).

5. The thread trimming mechanism according to claim 4, characterized in that: The telescopic member (500) comprises a fixed portion (520) and a movable portion (530), the movable portion (530) being cylindrical, the movable portion (530) being partially sleeved on the fixed portion (520) and moving relative to the fixed portion (520) along the first direction; The end of the fixed portion (520) facing away from the movable portion (530) is connected to the thread trimmer crank (231), and a pressure regulating screw (540) is provided on the fixed portion (520).

6. The thread trimming mechanism according to claim 5, characterized in that: It also includes an elastic member (510), the elastic member (510) being located inside the movable portion (530), and two ends of the elastic member (510) along the first direction respectively abutting against the movable portion (530) and the pressure-adjusting screw (540).

7. The thread trimming mechanism according to any one of claims 1 to 3, characterized in that: The transmission assembly (200) includes a ball (220), the ball (220) being rotatably connected to a first end of the thread trimmer crank (231), and the thread trimmer crank (231) being in sliding contact with a cam (210) surface of the cam (210) via the ball (220).

8. The thread trimming mechanism according to any one of claims 1 to 3, characterized in that: The device further comprises a controller (400) and a detector (410), wherein the driving assembly (100) comprises a motor (110), the motor (110) is connected to the cam (210), and the motor (110) is configured to drive the cam (210) to rotate around the first rotation axis (120); The controller (400) is electrically connected to the motor (110), and the controller (400) is configured to control the direction of rotation of the motor (110).

9. The thread trimming mechanism according to claim 8, characterized in that: The motor (110) is a stepping motor.

10. A sewing machine, characterized in that: It comprises a sewing machine body and a thread cutting mechanism (10) according to any one of claims 1 to 9, wherein the thread cutting mechanism (10) is connected to the sewing machine body.

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