Thread trimming structure of sewing machine

Abstract

The utility model provides a kind of thread cutting structure of sewing machine, belong to sewing machine technical field.It solves the problem that the thread tip on needle is too short to be easily off-line after tail needle thread cutting of existing sewing machine.The thread cutting structure of this sewing machine, sewing machine includes lower shaft, thread cutting moving knife and auxiliary moving knife, thread cutting moving knife and auxiliary moving knife are all sleeved on lower shaft, thread cutting moving knife and auxiliary moving knife can relatively rotate, thread cutting moving knife has the thread separation tip of being sharp head and the lead groove located in the rear side of thread separation tip, the thread cutting structure includes the thread blocking piece fixedly connected on thread cutting moving knife, one end of thread blocking piece is the thread blocking end of being strip, thread blocking end is inclinedly arranged from rear to front towards the groove bottom direction of lead groove, thread blocking end is located above thread cutting moving knife, and there is thread passing gap between thread blocking end and thread cutting moving knife.The thread cutting structure of this sewing machine effectively avoids the problem that thread tip is off-line when needle is raised on needle during resewing, so as to improve the multiple sewing efficiency of sewing machine.

Description

Technical Field

[0001] This utility model belongs to the field of sewing machine technology and relates to a thread-cutting structure for a sewing machine. Background Technology

[0002] A sewing machine is a device that uses one or more threads to create one or more stitches on fabric, allowing two or more layers of fabric to interweave or sew together. To improve sewing efficiency, sewing machines are usually equipped with a thread-cutting mechanism that automatically cuts off the top thread remaining on the fabric at the beginning of the sewing stitch.

[0003] Existing thread-cutting structures, such as the Chinese patent application [Authorization Announcement No.: CN118835402B], disclose a thread-cutting method using a double-moving-blade thread-cutting mechanism. The thread-cutting mechanism includes a first moving-blade assembly, a second moving-blade assembly, and a drive assembly. Both the first and second moving-blade assemblies are rotatably mounted on the outer periphery of a suitable rotary hook mechanism, with the rotary hook mechanism as the axis of rotation. The first moving-blade assembly is used to hook the sewing thread, and the second moving-blade assembly works in conjunction with the first moving-blade assembly to cut the thread. The first moving-blade assembly includes a thread-cutting moving blade and a first moving-blade holder. The thread-cutting moving blade has a thread hole groove, a hook groove one, and a hook groove two. Each groove extends through the thickness direction of the thread-cutting moving blade. The thread hole groove and the hook groove one are arranged along the rotation direction of the thread-cutting moving blade. The thread hole groove is located at the position of the hook groove one away from the tip of the thread-cutting moving blade. The tip of the blade has a first cutting edge with uneven flatness. The thread hole groove is used for the needle to pass through and cut and hook the sewing thread at the start of the sewing.

[0004] In the above structure, a thread hole groove, a hook groove one, and a hook groove two are opened on the thread cutting blade. During the sewing process, the sewing thread is hooked by the hook groove two. However, after the sewing is completed, a longer section of the thread needs to be reserved for the next sewing. But the hook groove two can only stretch the thread to a short length. As a result, after the sewing is completed, the thread left on the needle after the thread is cut is relatively short. This makes it easy for the thread end to come loose on the needle when sewing again, which affects the sewing machine's efficiency for multiple sewing operations. Utility Model Content

[0005] The purpose of this utility model is to address the aforementioned problems in existing technologies by proposing a thread-cutting structure for sewing machines. The technical problem to be solved by this utility model is: how to solve the problem that after the thread is cut by the tail needle in existing sewing machines, the thread end left on the needle is too short and easily comes loose.

[0006] The objective of this utility model can be achieved through the following technical solutions:

[0007] A thread-cutting structure for a sewing machine, the sewing machine including a lower shaft, a thread-cutting moving blade, and an auxiliary moving blade, both the thread-cutting moving blade and the auxiliary moving blade being sleeved on the lower shaft, and the thread-cutting moving blade and the auxiliary moving blade being rotatable relative to each other, the thread-cutting moving blade having a pointed thread-separating tip and a thread guide groove located behind the thread-separating tip, characterized in that the thread-cutting structure includes a thread-blocking piece fixedly connected to the thread-cutting moving blade, one end of the thread-blocking piece being a strip-shaped thread-blocking end, the thread-blocking end being inclined from back to front toward the bottom of the thread guide groove, the thread-blocking end being located above the thread-cutting moving blade, and a thread-passing gap being present between the thread-blocking end and the thread-cutting moving blade.

[0008] After sewing is completed, the thread-cutting blade rotates upwards towards the needle axis, guiding the top thread of the needle to the thread guide groove via the thread divider. Then, the thread-cutting blade rotates downwards in the opposite direction, and the relative movement of the thread-cutting blade and the auxiliary blade cuts the top thread within the thread guide groove. To extend the length of the cut top thread, a thread-stop plate is fixed to the thread-cutting blade. One end of the thread-stop plate is strip-shaped and is angled from back to front towards the bottom of the thread guide groove, positioned above the thread-cutting blade, with a thread-passing gap between the thread-stop plate and the thread-cutting blade. This structure allows the top thread, guided by the thread divider to the thread guide groove, to slide along the side wall of the thread-stop plate before cutting, and then, after sliding to the end of the thread-stop plate, to pass through the thread-passing gap between the thread-stop plate and the thread-cutting blade to the bottom of the thread guide groove. Subsequently, as the thread-cutting blade rotates downwards in the opposite direction, the thread-stopping plate moves downwards along with it. At this time, the thread-stopping end of the plate blocks the top thread, pulling it downwards from its original position at the bottom of the thread guide groove, causing it to bend and lengthen within the groove. When the thread-cutting blade and the auxiliary blade move relative to each other to cut the thread, the length of the cut top thread increases because it has already been pulled and lengthened by the thread-stopping plate. This results in a longer length of top thread remaining on the needle after sewing, effectively preventing the thread end from coming loose on the needle during subsequent stitches, thus improving the efficiency of multiple sewing operations.

[0009] In the thread-cutting structure of the sewing machine described above, the width of the thread-blocking end gradually decreases from the rear end to the front end.

[0010] The shape of the thread stop end allows the thread to quickly enter and exit the thread guide groove, and also provides a good thread support effect when cutting the thread. Thus, the thread stop can both extend the reserved thread and ensure that the sewing machine can cut the thread normally.

[0011] In the thread-cutting structure of the sewing machine described above, the front end of the thread stop is located in front of the thread guide groove.

[0012] This structure ensures that the thread stop has sufficient length and tilt angle to stretch the top thread, thus allowing more top thread to be reserved. This, in turn, ensures that the sewing machine can sew multiple times normally without the top thread coming off.

[0013] In the thread-cutting structure of the sewing machine described above, the thread-stopping end has a planar guide wall that is arranged vertically.

[0014] The guide wall allows the wire to slide along it, making it easier for the wire to slide into the bottom of the lead wire groove, thus making the sliding of the wire smoother.

[0015] In the thread-cutting structure of the sewing machine described above, the outer edge of the front side of the thread stop end has a guide surface that is inclined from top to bottom.

[0016] The guide surface allows the instant noodle thread to slide from the outer edge of the front side of the thread stop into the thread guide groove, thus extending the reserved noodle thread without affecting the cutting of the noodle thread.

[0017] In the thread-cutting structure of the sewing machine described above, the thread stop plate is arc-shaped, and the other end of the thread stop plate is a connecting end that is attached to and fixed to the thread-cutting blade. The side wall of the connecting end and the side wall of the thread stop end are transitioned by an arc.

[0018] This structure prevents the surface line from getting scratched during sliding, thus ensuring normal cutting of the surface line while extending the reserved surface line.

[0019] Compared with existing technologies, the thread-cutting structure of this sewing machine has the following advantages: When the moving thread-cutting blade and the auxiliary moving blade move relative to each other to cut the thread, the length of the cut thread increases because the top thread has been stretched and lengthened by the thread-stopping plate. This results in a longer length of top thread remaining on the needle after sewing, effectively preventing the thread end from coming loose on the needle during subsequent sewing, thus improving the sewing machine's efficiency for multiple sewing operations. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the assembled structure of this utility model.

[0021] Figure 2 This is a schematic diagram of the structure of the wire-cutting moving blade and the wire-blocking plate after assembly in this utility model.

[0022] Figure 3 This is a front view of the wire-cutting moving blade and the wire-blocking plate after assembly in this utility model.

[0023] Figure 4 This is a schematic diagram of the structure of the middle baffle plate of this utility model.

[0024] In the diagram, 1 is the lower shaft; 2 is the wire cutting blade; 21 is the wire separating tip; 22 is the wire guide groove; 3 is the auxiliary blade; 4 is the wire blocking plate; 41 is the wire blocking end; 41a is the guide wall; 41b is the guide surface; 42 is the connecting end; and 5 is the wire passage gap. Detailed Implementation

[0025] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0026] like Figure 1 and Figure 2 As shown, the sewing machine has a thread-cutting structure. The sewing machine includes a lower shaft 1, a thread-cutting moving blade 2, and an auxiliary moving blade 3. Both the thread-cutting moving blade 2 and the auxiliary moving blade 3 are sleeved on the lower shaft 1. The thread-cutting moving blade 2 and the auxiliary moving blade 3 can rotate relative to each other. The thread-cutting moving blade 2 has a pointed thread-separating tip 21 and a thread guide groove 22 located behind the thread-separating tip 21.

[0027] Specifically, such as Figure 1-3 As shown, the wire cutting structure includes a wire-blocking piece 4 fixedly connected to the wire cutting blade 2. One end of the wire-blocking piece 4 is a strip-shaped wire-blocking end 41. The wire-blocking end 41 is inclined from back to front toward the bottom of the lead wire groove 22. The wire-blocking end 41 is located above the wire cutting blade 2, and there is a wire-passing gap 5 between the wire-blocking end 41 and the wire cutting blade 2.

[0028] After sewing is completed, the thread-cutting blade 2 rotates upwards towards the needle axis, guiding the needle thread to the thread guide groove 22 via the thread-separating tip 21. Then, the thread-cutting blade 2 rotates downwards in the opposite direction, and the relative movement of the thread-cutting blade 2 and the auxiliary blade 3 cuts the thread within the thread guide groove 22. To extend the length of the cut thread, a thread-blocking plate 4 is fixed to the thread-cutting blade 2. One end of the thread-blocking plate 4 is strip-shaped, and the thread-blocking end 41 is inclined from back to front towards the bottom of the thread guide groove 22, with the thread-blocking end 41 positioned above the thread-cutting blade 2, and a thread-passing gap 5 between the thread-blocking end 41 and the thread-cutting blade 2. This structure allows the thread, guided by the thread separating tip 21 to the thread guide groove 22, to slide along the side wall of the thread stop end 41 as the thread cutting blade 2 rotates upwards towards the needle axis before cutting. After sliding to the end of the thread stop end 41, it can pass through the thread passage gap 5 between the thread stop end 41 and the thread cutting blade 2 and enter the bottom of the thread guide groove 22. Then, as the thread cutting blade 2 rotates downwards in the opposite direction, the thread stop plate 4 moves downwards with it. At this time, the thread stop end 41 of the thread stop plate 4 can block the thread, pulling the thread originally located at the bottom of the thread guide groove 22 downwards, causing the thread to bend and lengthen within the thread guide groove 22. When the thread cutting blade 2 and the auxiliary blade 3 move relative to each other to cut the thread, the length of the cut thread will increase because the thread has been pulled and lengthened by the thread stop plate 4. In this way, after sewing is completed, the length of the thread left on the needle will be longer, which effectively avoids the problem of the thread end coming loose on the needle when sewing again, thereby improving the sewing machine's efficiency for multiple sewing operations.

[0029] like Figure 2 and Figure 4 As shown, the width of the wire-blocking end 41 gradually decreases from the rear end to the front end. The front end of the wire-blocking end 41 is located in front of the lead wire groove 22. The wire-blocking end 41 has a planar guide wall 41a that is arranged vertically, and the outer edge of the front side of the wire-blocking end 41 has a guide surface 41b that is inclined from top to bottom.

[0030] like Figure 2-4 As shown, the wire-blocking piece 4 is arc-shaped, and the other end of the wire-blocking piece 4 is a connecting end 42 that is attached to the wire-cutting blade 2 and fixedly connected to the wire-cutting blade 2. The side wall of the connecting end 42 and the side wall of the wire-blocking end 41 are rounded.

[0031] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A thread-cutting structure for a sewing machine, the sewing machine comprising a lower shaft (1), a thread-cutting moving blade (2), and an auxiliary moving blade (3), wherein the thread-cutting moving blade (2) and the auxiliary moving blade (3) are both sleeved on the lower shaft (1), the thread-cutting moving blade (2) and the auxiliary moving blade (3) are rotatable relative to each other, the thread-cutting moving blade (2) having a pointed thread-separating tip (21) and a thread-leading groove (22) located behind the thread-separating tip (21), characterized in that, This wire cutting structure includes a wire-blocking piece (4) fixedly connected to the wire cutting blade (2). One end of the wire-blocking piece (4) is a strip-shaped wire-blocking end (41). The wire-blocking end (41) is inclined from back to front toward the bottom of the lead wire groove (22). The wire-blocking end (41) is located above the wire cutting blade (2), and there is a wire-passing gap (5) between the wire-blocking end (41) and the wire cutting blade (2).

2. The thread-cutting structure of the sewing machine according to claim 1, characterized in that, The width of the wire-blocking end (41) gradually decreases from the rear end to the front end.

3. The thread-cutting structure of the sewing machine according to claim 1 or 2, characterized in that, The front end of the wire-blocking end (41) is located on the front side of the lead wire groove (22).

4. The thread-cutting structure of the sewing machine according to claim 1 or 2, characterized in that, The line-blocking end (41) has a planar guide wall (41a) that is arranged vertically.

5. The thread-cutting structure of the sewing machine according to claim 1 or 2, characterized in that, The outer edge of the front side of the line-blocking end (41) has a guide surface (41b) that is inclined from top to bottom.

6. The thread-cutting structure of the sewing machine according to claim 1 or 2, characterized in that, The wire-blocking piece (4) is arc-shaped, and the other end of the wire-blocking piece (4) is a connecting end (42) that is attached to the wire-cutting blade (2) and fixedly connected to the wire-cutting blade (2). The side wall of the connecting end (42) and the side wall of the wire-blocking end (41) are arc-shaped.

Images