Automatic shearing mechanism for preventing bird nests

Abstract

The utility model relates to an automatic shearing mechanism of anti -bird nest, including the seat body, the seat body on setting drive mechanism, transmission mechanism and clamping and shearing mechanism, drive mechanism drives clamping and shearing mechanism action through transmission mechanism, clamping and shearing mechanism include moving knife, fixed knife and blade spring, fixed knife is fixed on the seat body, moving knife is movably arranged on the seat body, and the machine needle avoidance hole is set up in moving knife front part, and the pressure rod of blade spring abuts on moving knife front part upper surface, and moving knife rear part passes through transmission mechanism and drive mechanism, and drive mechanism drives moving knife movement to have three section stroke structure, the utility model first clamps the thread end when starting to sew, and the surplus thread end is cut after needle stability, plays the effect of better anti -bird nest and anti -threading, and thread end clamping is executed by elastic mechanism, is not restricted by the fine yarn, has the characteristics of reasonable in structure, stitch beautiful, good reliability, strong applicability.

Description

Technical Field

[0001] This utility model relates to sewing machine technology, specifically an automatic bird nest cutting mechanism. Background Technology

[0002] To prevent the top thread from slipping off the needle during the initial stitch, sewing equipment often leaves a long thread end after passing through the needle hole. This long thread end then tangles with the bottom or top thread during the initial stitch, forming a tangled ball commonly known as a "bird's nest." This results in unsightly stitches. To solve this problem, anti-bird's nest mechanisms have been proposed. Most existing anti-bird's nest mechanisms clamp the thread end during the initial stitch and then release it afterward to prevent tangling. For example, utility model patent CN215209964U discloses a dual-purpose anti-bird's nest and anti-slipping device and a sewing machine containing this device, used to pull the thread end after the needle passes through the needle plate. The sewing thread end is kept away from the needle; it includes: an actuator, which is disposed under the needle plate for driving the sewing thread end to move; a power unit for driving the actuator to perform the action of driving the sewing thread end to move; and an electrical control unit, which is electrically connected to the power unit for sensing the position of the needle and driving the power unit to perform the driving action. This utility model can prevent the thread end from being caught in the bottom of the fabric by the shuttle when sewing, thereby achieving the effect of preventing bird nests; moreover, the entire anti-bird nest and anti-slipping dual-purpose device of this utility model is located under the table panel. This design can reduce the possibility of accidental contact by the operator, improve safety, and also has the function of preventing thread slippage.

[0003] While the above structure solves the problem of the "bird's nest" (the thread ends are pulled by the actuator during the start-up, thus solving the problems of the "bird's nest" and the thread coming loose), the thread ends left behind by the actuator are still relatively long, resulting in a long thread end in each stitch, making the stitches less aesthetically pleasing.

[0004] For example, utility model CN221721104U discloses a double-movable-blade thread-cutting mechanism for preventing bird nests and a sewing machine. The double-movable-blade thread-cutting mechanism for preventing bird nests includes a fixed starting blade, a main moving blade and a post-sewing moving blade, both movably configured on the outer periphery of the rotary hook in the sewing machine. The main moving blade is provided with a starting thread-cutting blade, a thread-hooking groove, a thread-separating groove, and a post-sewing thread-cutting blade. The thread-hooking groove allows the needle in the sewing machine to pass through. When the main moving blade moves toward the starting blade, the starting thread-cutting blade can engage with the starting blade, reliably achieving bird nest prevention during the starting stitch. When the main moving blade and the post-sewing moving blade move toward each other, the post-sewing thread-cutting blade can engage with the post-sewing moving blade, achieving automatic thread cutting after sewing. Furthermore, the automatic thread cutting after sewing is a double-movable-blade structure, which allows the engagement position of the post-sewing thread-cutting blade and the post-sewing moving blade to be closer to the central axis of the needle, thereby resulting in shorter residual thread ends on the fabric after thread cutting at the end of sewing.

[0005] The above-mentioned structure is mainly achieved by the cooperation of the starting cutter and the main moving cutter. Different sewing machines have different thread cutting mechanisms, and some thread cutting mechanisms do not have a main moving cutter. In addition, due to the different materials and thicknesses of the sewing machine thread, the above-mentioned structure cannot adjust the gap between the starting cutter and the main moving cutter. Therefore, the above-mentioned structure has great limitations and can only be used for yarns of a specified thickness and specific sewing machine models. Utility Model Content

[0006] The purpose of this utility model is to provide an automatic anti-bird nest cutting mechanism. An independent automatic anti-bird nest cutting mechanism is set below the needle plate and on one side of the thread cutting mechanism. When starting to sew, it can first clamp the thread end, and after the needle starts to stabilize, it can cut off the excess thread end, which can effectively prevent bird nests and prevent the thread from coming off. Moreover, the thread end clamping is performed by an elastic mechanism, which is not limited by the fineness of the yarn. It can be used in various sewing equipment with different functions and has the characteristics of reasonable structure, beautiful stitches, good reliability and strong applicability.

[0007] To achieve the above objectives, the following technical solution is adopted: An automatic bird nest shearing mechanism includes a base, on which a drive mechanism, a transmission mechanism, and a clamping and shearing mechanism are mounted. The drive mechanism drives the clamping and shearing mechanism to operate via the transmission mechanism. The clamping and shearing mechanism comprises a moving blade, a fixed blade, and a blade spring. The fixed blade is fixed to the base, and the moving blade is movably mounted on the base. A needle clearance hole is provided at the front of the moving blade. The pressure rod of the blade spring abuts against the upper surface of the front of the moving blade. The rear of the moving blade is connected to the drive mechanism via the transmission mechanism. The drive mechanism drives the moving blade to move in a three-stage stroke structure. The first stage is from a retracted state to an extended state, where the needle clearance hole on the moving blade corresponds to the position of the needle. The second stage is from an extended state to a pressing state, where the needle clearance hole retracts to the pressure rod position of the blade spring. The third stage is from the pressing state to a retracted state, where the moving blade resets, and the blade edge of the fixed blade engages with the needle clearance hole of the moving blade to complete the cutting action.

[0008] The top of the base is provided with a guide groove, the moving blade is housed in the guide groove, and the drive mechanism drives the moving blade to move linearly along the guide groove; the fixed blade is set on the upper surface of the moving blade and fixed on the base, the blade spring body is fixed on the base, and the pressure rod at the front of the blade spring extends to the front side of the fixed blade and abuts against the upper surface at the front of the moving blade.

[0009] The pressure rod is U-shaped, with one end of the U-shaped pressure rod integrated with the blade spring body. The spring body is fixed to one side of the fixed blade. The U-shaped pressure rod is formed by bending the pressure rod to the front end of the fixed blade, passing around the front end of the fixed blade, bending backward, and extending to the other side of the fixed blade. This allows the U-shape to surround the front end and both sides of the fixed blade. The U-shaped pressure rod abuts against the upper surface of the front end of the moving blade and maintains elastic pressure on the upper surface of the moving blade.

[0010] The drive mechanism includes a motor, which is fixedly connected to the base and electrically connected to an electronic control unit. The output shaft of the motor is movably connected to the rear of the moving blade via a crank and a connecting rod. The electronic control unit controls the movement stroke of the moving blade by controlling the rotation angle of the motor output shaft.

[0011] This utility model's automatic bird nest cutting mechanism adds a blade spring and cleverly matches the pressure rod of the blade spring with the needle clearance hole of the moving cutter head. When starting the needle, it presses down the thread end, so that the thread will not come loose due to pulling during the needle start. After the needle start is stable, it can also cut off the excessively long thread end to make the stitches more beautiful. It has the characteristics of reasonable structure, beautiful stitches, good reliability and strong applicability. Attached Figure Description

[0012] Figure 1 This is a schematic diagram (a) of the structure of the present invention on a sewing equipment; Figure 2 This is a schematic diagram (II) of the structure of this utility model on a sewing equipment; Figure 3 This is a schematic diagram of the structure of the first embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the first embodiment of the present invention from another direction; Figure 5 This is a schematic diagram of a portion of the structure of the first embodiment of the present utility model; Figure 6 This is a schematic diagram of the structure of the first embodiment of the present invention, showing the separation of the suction cover plate; Figure 7 This is a schematic diagram (a) of the structure of the base body according to the first embodiment of the present utility model; Figure 8 This is a schematic diagram (II) of the structure of the base body according to the first embodiment of this utility model; Detailed Implementation

[0013] like Figure 1-8As shown, an automatic bird nest shearing mechanism includes a base 1. The base 1 is equipped with a drive mechanism, a transmission mechanism 4, and a clamping and shearing mechanism 5. The drive mechanism drives the clamping and shearing mechanism 5 to move through the transmission mechanism. The clamping and shearing mechanism 5 includes a moving blade 51, a fixed blade 52, and a blade spring 53. The fixed blade 52 is fixed on the base 1, and the moving blade 51 is movably mounted on the base 1. The moving blade 51 has a needle clearance hole 511 at its front. The pressure rod 531 of the blade spring 53 abuts against the upper surface of the front of the moving blade 51. The rear of the moving blade 51 is connected to the drive mechanism through the transmission mechanism 4.

[0014] The top of the base 1 is provided with a guide groove 12, the movable blade 51 is housed in the guide groove 12, and the drive mechanism drives the movable blade 51 to move linearly along the guide groove 12; the fixed blade 52 is set on the upper surface of the movable blade 51 and fixed on the base 1, the body of the blade spring 53 is fixed on the base 1, and the pressure rod 531 at the front of the blade spring 53 extends to the front side of the fixed blade 52 and abuts against the upper surface of the front of the movable blade 51.

[0015] The pressure rod 531 is U-shaped, with one end of the U-shaped pressure rod integrated with the blade spring body. The blade spring body is fixed to one side of the fixed blade 52. The U-shaped pressure rod is bent to the front end of the fixed blade 52, and then bends backward and extends to the other side of the fixed blade 52 to form the U-shaped pressure rod. This makes the U-shape surround the front end and both sides of the fixed blade 52. In this way, the U-shaped pressure rod surrounds the front end of the fixed blade 52 and will not shift. The U-shaped pressure rod uses the elasticity of the spring to abut against the upper surface of the front end of the moving blade 51 and maintains elastic pressure on the upper surface of the moving blade 51, thereby ensuring reliability and stability when gripping the wire end.

[0016] The drive mechanism has three strokes. The drive mechanism includes a motor 3, which is fixedly connected to the base 1. The motor 3 is electrically connected to the electronic control unit. The output shaft of the motor 3 is movably connected to the rear of the moving blade 51 through a crank 41 and a connecting rod 42. The electronic control unit controls the movement stroke of the moving blade 51 by controlling the rotation angle of the output shaft of the motor 3. The first stroke is when the moving blade 51 moves from the retracted state to the extended state. In the extended state, the needle clearance hole 511 on the moving blade 51 corresponds to the position of the needle. The second stroke is when the moving blade 51 retracts from the extended state to the pressing state. In the pressing state, the needle clearance hole 511 of the moving blade retracts to the position of the pressure rod 531 of the blade spring 53. The third stroke is when the pressing state retracts to the retracted state. At this time, the moving blade 51 is reset, and when the moving blade is reset, the blade edge of the fixed blade 52 cooperates with the needle clearance hole of the moving blade 51 to complete the cutting action.

[0017] The working process of this utility model is as follows: When the needle is started, the electric control motor 3 drives the moving blade 51 from the retracted state to the extended state through the crank 41 and connecting rod 42. At this time, the needle clearance hole 511 of the moving blade 51 is exactly aligned with the needle hole of the needle plate 2. The needle passes through the needle plate 2 and enters the needle clearance hole 511. At this time, the thread end on the needle also enters the needle clearance hole 511. Then, as the needle returns to its original position and just leaves the needle clearance hole 511, but before the thread end leaves the needle clearance hole 511, the electric control motor 3 rotates in the opposite direction as previously set. The angle is not fully reset. At this time, the moving blade 51 takes the thread end that has entered the needle clearance hole 51 and retracts. The thread end is just clamped by the pressure rod 531 of the blade spring 53 and the upper surface of the blade head. The advantage of this is to ensure that the thread will not be pulled and detached due to the untimely loosening of the thread during subsequent needle operations. After the needle has completed 2 to 3 stitches, the electric control motor 3 is fully reset. At this time, the moving blade 51 retracts further and cooperates with the fixed blade through the edge of the needle clearance hole 511 to cut the thread end. This way, the thread end is shorter and will not affect the appearance of the stitch due to the thread end being too long.

[0018] Considering the short thread ends that will be generated after cutting the wire, this utility model further provides a suction channel at the bottom of the base 1. The suction port 16 at the front end of the suction channel corresponds to the cutting positions of the moving blade 51 and the fixed blade 52. The suction channel is connected to the blowing device through a duct. The suction channel includes a suction groove 14 at the bottom of the base 1. The suction groove 14 is closed by a suction cover 15 to form the suction channel. The front end of the suction groove 14 has a suction port 16 at the position corresponding to the cutting positions of the moving blade 51 and the fixed blade 52. The rear end of the suction groove 14 has an air outlet 17. A connecting connector 18 is installed at the air outlet. The connecting connector 18 is connected to the blowing device through a duct. The thread segments generated after cutting are promptly sucked away through the suction channel.

[0019] The automatic bird nest cutting mechanism of this utility model is equipped with a blade spring, and the pressure rod of the blade spring is cleverly matched with the needle clearance hole of the moving cutter head. When starting to sew, the thread end is pressed down, so that the top thread will not come loose due to the lack of timely pulling when starting to sew. After sewing a few stitches, the excessively long thread end can be cut off to make the stitches more beautiful.

[0020] In addition, this utility model sets the anti-bird nest automatic cutting mechanism as an independent module and fixes the module to the bottom of the needle plate. It can be installed as long as there is enough space under the needle plate, and it is suitable for various sewing equipment with different functions. It has the characteristics of reasonable structure, beautiful stitches, good reliability and strong applicability.

Claims

1. An automatic bird nest shearing mechanism, comprising a base (1), wherein a driving mechanism, a transmission mechanism (4), and a clamping and shearing mechanism (5) are provided on the base (1), the driving mechanism driving the clamping and shearing mechanism (5) to operate through the transmission mechanism, characterized in that: The clamping and shearing mechanism (5) includes a moving blade (51), a fixed blade (52) and a blade spring (53). The fixed blade (52) is fixed on the base (1), and the moving blade (51) is movably mounted on the base (1). The moving blade (51) has a needle clearance hole (511) at the front. The pressure rod (531) of the blade spring (53) abuts against the upper surface of the front of the moving blade (51). The rear of the moving blade (51) is connected to the drive mechanism through the transmission mechanism (4). The drive mechanism has three strokes. The first stroke is when the moving blade (51) moves from the retracted state to the extended state. In the extended state, the needle clearance hole (511) on the moving blade (51) corresponds to the position of the needle. The second stroke is when the moving blade (51) moves from the extended state to the pressing state. In the pressing state, the needle clearance hole (511) of the moving blade moves back to the position of the pressure rod (531) of the blade spring (53). The third stroke is when the pressing state moves back to the retracted state. At this time, the moving blade (51) is reset, and when the moving blade is reset, the blade edge of the fixed blade (52) cooperates with the needle clearance hole of the moving blade (51) to complete the cutting action.

2. The automatic bird nest shearing mechanism as described in claim 1, characterized in that: The top of the base (1) is provided with a guide groove (12), the moving blade (51) is housed in the guide groove (12), and the driving mechanism drives the moving blade (51) to move linearly along the guide groove (12); the fixed blade (52) is set on the upper surface of the moving blade (51) and fixed on the base (1), the body of the blade spring (53) is fixed on the base (1), and the pressure rod (531) at the front of the blade spring (53) extends to the front side of the fixed blade (52) and abuts against the upper surface of the front of the moving blade (51).

3. An automatic shearing mechanism for preventing bird nests as defined in claim 2, wherein: The pressure rod (531) is U-shaped. One end of the U-shaped pressure rod is integrated with the blade spring body. The blade spring body is fixed on one side of the fixed blade (52). The U-shaped pressure rod is formed by bending the pressure rod to the front end of the fixed blade (52), passing around the front end of the fixed blade (52), bending backward, and extending to the other side of the fixed blade (52). The U-shape surrounds the front end and both sides of the fixed blade (52). The part of the U-shaped pressure rod abuts against the upper surface of the front end of the moving blade (51) and maintains elastic pressure on the upper surface of the moving blade (51).

4. An automatic shearing mechanism for preventing bird nests as defined in claim 2, wherein: The drive mechanism includes a motor (3), which is fixedly connected to the base (1). The motor (3) is electrically connected to the electric control unit. The output shaft of the motor (3) is movably connected to the rear of the moving blade (51) through a crank (41) and a connecting rod (42). The electric control unit controls the movement stroke of the moving blade (51) by controlling the rotation angle of the output shaft of the motor (3).

5. An automatic shearing mechanism for preventing bird nests as defined in claim 1, wherein: The bottom of the seat (1) is also provided with a suction channel. The position of the suction port (16) at the front end of the suction channel corresponds to the position of the shearing port of the moving blade (51) and the fixed blade (52). The suction channel is connected to the blowing device through the air pipe.

6. The automatic bird nest cutting mechanism as described in claim 5, characterized in that: The suction channel includes a suction groove (14) at the bottom of the base (1). The suction groove (14) is closed by a suction cover (15) to form the suction channel. A suction port (16) is provided at the front end of the suction groove (14) at the position corresponding to the shearing opening of the moving blade (51) and the fixed blade (52). An air outlet (17) is provided at the rear end of the suction groove (14). A connecting joint (18) is installed at the air outlet. The air duct of the connecting joint (18) is connected to the blowing device.

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