Bird nest prevention and thread drop prevention mechanism

Abstract

The utility model relates to a kind of anti-bird nest anti-off-line mechanism, including seat, the seat is provided with driving mechanism, transmission mechanism and clamping and shearing mechanism, driving mechanism drives clamping and shearing mechanism action by transmission mechanism;The clamping and shearing mechanism includes moving knife, fixed knife and blade spring, fixed knife is fixed on seat, moving knife is movably arranged on seat, moving knife front part is provided with machine needle avoiding hole, the pressure rod of blade spring is abutted on moving knife front part upper surface, moving knife rear portion is through transmission mechanism with driving mechanism, driving mechanism drives moving knife to move with three-stage stroke structure;The utility model first clamps thread end when starting seam, the excess thread is cut after needle is stable, play the effect of better anti-bird nest and anti-off-line, and thread end clamping is executed by elastic mechanism, not by yarn fine restriction, with the characteristics of structure reasonable, stitch beautiful, good reliability, strong applicability.

Description

Technical Field

[0001] This utility model relates to sewing machine technology, specifically a mechanism for preventing bird nests and thread breakage. 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 anti-bird nest and anti-loosening mechanism. An independent anti-bird nest and anti-loosening mechanism is set below the needle plate and on one side of the thread cutting mechanism. The anti-bird nest and anti-loosening mechanism is fixed to the machine base by a connecting plate. It only requires a positioning groove to be opened on the top of the machine base to be fixed to the connecting plate. It is very convenient to modify and disassemble. When sewing, it can clamp the thread end first. After the needle starts to stabilize, the excess thread end is cut off, which effectively prevents bird nests and prevents the thread from detaching. Moreover, the thread end clamping is performed by an elastic mechanism, which is not limited by the fineness of the yarn. It can be improved as long as there is a needle plate and space below the needle plate. It can be adapted to various sewing equipment with different functions. It 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: A bird nest prevention and anti-loosening 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 base is fixed to the bottom of a needle plate via a connecting part at its top. The clamping and shearing mechanism includes 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, and 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... The transmission mechanism is connected to the drive mechanism. The drive mechanism drives the moving blade to move in a three-stage stroke structure. The first stage is when the moving blade moves from the retracted state to the extended state. In the extended state, the needle clearance hole on the moving blade corresponds to the position of the needle. The second stage is when the moving blade moves from the extended state to the pressing state. In the pressing state, the needle clearance hole of the moving blade moves back to the pressure rod position of the blade spring. The third stage is when the pressing state moves back to the retracted state. At this time, the moving blade is reset, and when the moving blade is reset, the blade edge of the fixed blade cooperates with the needle clearance hole of the moving blade to complete the cutting action.

[0008] The top of the base is provided with an upward protrusion, and the base is connected to the bottom of the connecting plate through the protrusion. The corresponding position of the needle plate on the top of the base is provided with a positioning groove for the connecting plate, and the connecting plate is fixed in the positioning groove.

[0009] 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.

[0010] 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.

[0011] The driving mechanism includes a first linear drive device and a second linear drive device. The first linear drive device drives in the same direction as the guide groove, and the second linear drive device drives in a direction perpendicular to the guide groove. The second linear drive device is located at the bottom of the base, and a limiting slider is connected to its upper end. The limiting slider is housed in the longitudinal guide groove of the base, and the second linear drive device drives the limiting slider to move up and down within the longitudinal guide groove. The rear part of the moving blade is connected to the first linear drive device on the rear side of the base via a movable connecting shaft. A downwardly protruding limiting connecting post is provided at the bottom of the movable connecting shaft. When the limiting slider rises, it can block the backward movement path of the limiting connecting post and limit the backward movement stroke of the moving blade. When the limiting slider falls, it will not block the limiting connecting post.

[0012] The drive mechanism includes a first linear drive device and a second linear drive device. Both sets of linear drive devices are located on the rear side of the base and have the same driving direction. The strokes of the two sets of linear drive devices are superimposed and connected to the rear of the moving blade.

[0013] This utility model sets the anti-bird nest and anti-loosening mechanism as an independent module, and fixes the module to the positioning groove on the top of the machine base through the connecting 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.

[0014] In addition, the anti-bird nest and anti-loosening 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 on the moving blade to press the thread end when starting the needle, so that the thread will not be pulled off due to the needle when starting the needle; after the needle starts is stable, the excessive thread end can be cut off to make the stitches more beautiful; the specific structure is reasonable, the stitches are beautiful, the reliability is good, and the applicability is strong. Attached Figure Description

[0015] 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 clamping and shearing mechanism of the present invention when the moving blade is in the extended state; Figure 4 This is a schematic diagram of the clamping and shearing mechanism of the present invention when the moving knife is in the wire pressing state; Figure 5 This is a schematic diagram of the clamping and shearing mechanism of the present invention when the moving blade is in the retracted state; Figure 6 This is a schematic diagram of the bottom structure of the anti-bird nest and anti-loosening mechanism of this utility model; Figure 7 This is a schematic diagram of the structure of the base of this utility model (I); Figure 8 This is a schematic diagram (II) of the structure of the base of this utility model; Figure 9 This is a schematic diagram of the drive mechanism, transmission mechanism, and clamping and shearing mechanism of this utility model. Detailed Implementation

[0016] like Figure 1-9 As shown, an anti-bird nest and anti-loosening mechanism includes a base 1 and a needle plate. The base 1 is provided with a drive mechanism, a transmission mechanism and a clamping and cutting mechanism 5. The drive mechanism drives the clamping and cutting mechanism 5 to move through the transmission mechanism. The top of the base 1 is provided with an upwardly protruding boss 11. The base 1 is connected to the bottom of the connecting plate 22 through the boss 11. The top of the base 2 is provided with a positioning groove 21 for the connecting plate at the position corresponding to the needle plate. The connecting plate 22 is fixedly connected in the positioning groove 21.

[0017] The clamping and shearing mechanism 5 includes a movable blade 51, a fixed blade 52, and a blade spring 53. The fixed blade 52 is fixed on the base 1, and the movable blade 51 is movably mounted on the base 1. The movable 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 movable blade 51. The rear of the movable blade 51 is connected to the drive mechanism through a transmission mechanism.

[0018] 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.

[0019] 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.

[0020] The driving mechanism employs a linear drive device, such as a cylinder or an electromagnet. The driving mechanism includes a first linear drive device 6 and a second linear drive device 7. The first linear drive device 6 drives in the same direction as the guide groove 12, while the second linear drive device 7 drives in a direction perpendicular to the guide groove 12. The second linear drive device 7 is located at the bottom of the base 1, and a limiting slider 71 is connected to its upper end. The limiting slider 71 is housed within the longitudinal guide groove 13 of the base 1. The second linear drive device 7 drives the limiting slider 71 in the longitudinal guide groove 13. The blade 51 moves up and down within the groove 13; the rear of the blade 51 is connected to the first linear drive device 6 on the rear side of the base 1 via a movable connecting shaft 43. The bottom of the movable connecting shaft 43 is provided with a downwardly protruding limiting connecting post 44; when the limiting slider 71 rises, it can block the backward movement path of the limiting connecting post 44 and limit the backward movement stroke of the blade 51; when the limiting slider 71 falls, it will not block the movement path of the limiting connecting post 44; the base 1 is also provided with a blade stroke limiting block 19, which is located on the rear side of the guide groove 12 and is used to limit the maximum stroke of the blade 51 when it retracts.

[0021] 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.

[0022] The working process of this utility model is as follows: When starting the needle, the first linear drive device 6 pushes the moving blade 51 from the retracted state to the extended state through the movable connecting shaft 43. At the same time, the second linear drive device 7 pushes the limiting slider 71 upward to below the movable connecting shaft 43. At this time, the needle clearance hole 511 of the moving blade 51 is exactly aligned with the needle hole of the needle plate. The needle passes through the needle plate 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 resets and just disengages from the needle clearance hole 511, but before the thread end has disengaged from the needle clearance hole 51, the first linear drive device 6 resets backward. The limiting connecting post 44 at the bottom of the movable connecting shaft 43 is blocked by the limiting slider 71. At this time, the moving blade 51... 1. The thread end retracts into the needle clearance hole 51. The thread end is clamped by the pressure rod 531 of the blade spring 53 and the upper surface of the blade head. This ensures that the thread will not be pulled off due to untimely loosening of the thread during subsequent needle operations. After the needle completes 2 to 3 stitches, the second linear drive device 7 resets and drives the limit slider 71 to descend. The limit connecting post 44 is not blocked by the limit slider 71. The first linear drive device 6 drives the moving blade 51 to retract further. The moving blade 51 will be blocked by the moving blade stroke limit block 19, indicating that the moving blade 51 has been reset and is ready for the next operation. During this period, the thread end is cut by the fixed blade along the edge of the needle clearance hole 511. This way, the thread end is shorter and will not affect the appearance of the stitch due to excessive thread length.

[0023] 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.

[0024] The anti-bird nest and anti-loosening 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 blade head. When starting to sew, the thread end is pressed down, so that the top thread will not be loosened and not pulled in time, causing the thread to come loose. After sewing a few stitches, the excessively long thread end can be cut off to make the stitches more beautiful.

[0025] In addition, this utility model sets the anti-bird nest and anti-loosening mechanism as an independent module, and fixes the module in the positioning groove on the top of the machine base below the needle plate. It can be installed as long as the space under the needle plate is sufficient, 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.

[0026] Alternatively, the three-stage stroke of this utility model can be achieved by superimposing the strokes of two sets of linear drive devices. Both sets of linear drive devices are set on the rear side of the base and drive in the same direction. The drive rods of the two sets of linear drive devices are coaxial or in the same direction. In this way, the strokes are superimposed and connected to the rear of the moving blade. When the drive rods of the two sets of linear drive devices extend simultaneously, the moving blade is in the extended state. When only one set of linear drive devices retracts its drive rod, the moving blade is in the pressing state. When both sets of linear drive devices retract their drive rods, the moving blade is in the retracted state.

Claims

1. A bird nest prevention and anti-loosening mechanism, comprising a base (1), wherein a drive mechanism, a transmission mechanism, and a clamping and shearing mechanism (5) are provided on the base (1), the drive mechanism drives 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 a transmission mechanism. 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. The top of the base (1) is provided with an upward protrusion (11). The base (1) is connected to the bottom of the connecting plate (22) through the protrusion (11). The position of the corresponding needle plate on the top of the machine base (2) is provided with a positioning groove (21) for the connecting plate. The connecting plate (22) is fixedly connected in the positioning groove (21).

2. The anti-bird nest and anti-thread-dropping 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. The anti-bird nest and anti-thread-dropping mechanism as described in claim 2, characterized in that: 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. The anti-bird nest and anti-thread detachment mechanism as described in claim 1, characterized in that: 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.

5. The anti-bird nest and anti-thread-dropping mechanism as described in claim 4, 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.

6. The anti-bird nest and anti-thread-dropping mechanism as described in claim 2, characterized in that: The driving mechanism includes a first linear drive device (6) and a second linear drive device (7). The driving direction of the first linear drive device (6) is the same as that of the guide groove (12), and the driving direction of the second linear drive device (7) is perpendicular to that of the guide groove (12). The second linear drive device (7) is provided with the bottom of the base (1), and the upper end of the second linear drive device (7) is connected to a limiting slider (71). The limiting slider (71) is housed in the longitudinal guide groove (13) of the base (1). The limit slider (71) moves up and down in the longitudinal guide groove (13); the rear of the moving blade (51) is connected to the first linear drive device (6) on the rear side of the base (1) through the movable connecting shaft (43), and the bottom of the movable connecting shaft (43) is provided with a downward protruding limit connecting post (44); when the limit slider (71) rises, it can block the backward movement path of the limit connecting post (44) and limit the backward movement stroke of the moving blade (51); when the limit slider (71) falls, it will not block the movement path of the limit connecting post (44).

7. The anti-bird nest and anti-thread detachment mechanism as described in claim 6, characterized in that: The base (1) is also provided with a moving blade stroke limit block (19), which is located on the rear side of the guide groove (12).

8. The anti-bird nest and anti-thread-dropping mechanism as described in claim 2, characterized in that: The drive mechanism includes a first linear drive device and a second linear drive device. Both linear drive devices are located on the rear side of the base and have the same driving direction. The strokes of the drive rods of the two linear drive devices are superimposed and connected to the rear of the moving blade.

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