A thread-picking structure for a sewing machine

Abstract

This invention provides a thread-pulling structure for a sewing machine, belonging to the field of sewing machine technology. It solves the problem of preventing bird's nest-like thread tangles. The sewing machine includes a housing with a needle assembly slidably connected vertically inside. A thread releaser is fixed to the side wall of the housing. The thread-pulling structure includes an electronic thread clamp fixed to the outer wall of the housing and a lever vertically positioned above the thread releaser and the electronic thread clamp. The lower end of the lever is bent to form a thread loop. The thread-pulling structure also includes a cylinder fixed to the top of the housing. The drive shaft of the cylinder is arranged radially along the needle assembly. The cylinder is connected to the upper end of the lever via a transmission assembly and can drive the lower end of the lever to swing closer to or away from the outer wall of the housing. This thread-pulling structure effectively prevents bird's nest-like thread tangles.

Description

Technical Field

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

[0002] Sewing machines are very common sewing devices in current technology. They use a needle to stitch one or more threads onto the fabric to form one or more stitches, allowing one or more layers of fabric to interweave or sew together. In actual operation, especially at the end of a sewing job, to prevent the top thread from detaching from the needle when starting the next stitch, a certain length of thread end is usually left when cutting the thread. In addition, to prevent the top thread and bottom thread from interweaving multiple times and forming a bird's nest-like tangled thread when starting the next stitch, the needle usually hooks the top thread through the thread hole of the rotary hook cutter. Then, the cutter rotates a certain range and works with the thread clamping plate located on one side of the cutter to clamp the head of the top thread, thus ensuring that the head of the top thread is taut.

[0003] However, in actual operation, because the top thread needs to be threaded through the thread releaser on the machine housing before it is inserted into the needle eye, there will be a certain amount of friction between the top thread and the thread releaser. This causes the length of the thread end on the needle to become shorter when starting to sew. At this time, even if the thread hole of the cutter hooks the top thread, the length of the top thread under the cutter cannot extend to the thread clamping plate, so the top thread cannot be clamped by the thread clamping plate. This causes the thread end to be in a flexed state. When the sewing machine is sewing normally, it may cause a bird's nest-like tangled thread. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a thread-pulling structure for sewing machines. The technical problem this invention aims to solve is: how to prevent the occurrence of bird's nest-like thread tangles.

[0005] The objective of this utility model can be achieved through the following technical solution: a thread-pulling structure for a sewing machine, the sewing machine including a housing with a needle assembly slidably connected vertically inside, a thread releaser fixed on the side wall of the housing, the thread-pulling structure including an electronic thread clamp fixed on the outer side wall of the housing and a lever vertically arranged above the thread releaser and the electronic thread clamp, the lower end of the lever being bent to form a thread loop, the thread-pulling structure also including a cylinder fixed to the top of the housing, the drive shaft of the cylinder being arranged radially along the needle assembly, the cylinder being connected to the upper end of the lever through a transmission assembly and capable of driving the lower end of the lever to swing closer to or away from the outer side wall of the housing.

[0006] The difference between this application and the prior art lies in the following: An electronic thread clamp is installed on the outer wall of the machine housing, and a vertically positioned lever is mounted thereon. A cylinder mounted on the top of the machine housing acts as a drive source, working in conjunction with a transmission assembly to drive the lever. This allows the lower end of the lever to swing, moving closer to or away from the outer wall of the machine housing. Furthermore, in the prior art, the top thread is originally placed in the thread releaser before being threaded through the needle in the needle assembly. This application, however, additionally includes an electronic thread clamp and a lever. Therefore, the threading path is: thread releaser, thread loop at the lower end of the lever, electronic thread clamp, and needle assembly. Through this path, in actual operation—that is, after sewing a batch of fabric and before thread cutting—the electronic thread clamp closes to clamp the top thread (the end of the top thread that has not passed through the needle), and the thread releaser simultaneously feeds the thread. At this time, the cylinder starts and drives the transmission assembly, which in turn drives the upper end of the lever to move closer to or away from the outer wall of the machine housing. The machine moves inwards towards the outer wall of the casing, then drives the upper end of the lever to move outwards away from the outer wall of the casing, causing the lower end of the lever to move in the opposite direction. During this process, because the top thread is clamped, the tail of the thread is continuously pulled, increasing the length of the top thread between the electronic thread clamp and the thread releaser. This ensures that the top thread between the electronic thread clamp and the thread releaser is in a flexed state. Under these conditions, the top thread is then cut by the cutter. When performing the next sewing operation, because the portion of the top thread left between the electronic thread clamp and the thread releaser is flexed, the needle is inserted and the top thread is placed in the thread hole of the cutter. When the cutter rotates, the top thread has sufficient slack to move synchronously with the cutter without coming out of the thread hole. Finally, the thread clamping plate clamps the thread end, ensuring that the thread end remains taut and preventing the thread end from being sewn onto the fabric and forming a bird's nest-like clump when starting to sew.

[0007] In the thread-picking structure of the sewing machine described above, a mounting bracket is fixed to the top outer wall of the machine housing. The cylinder is fixed to the mounting bracket. The transmission assembly includes a lever crank, a connecting plate, and a fixing plate. The fixing plate is connected and fixed to the drive end of the cylinder. The lever crank is rotatably connected to the mounting bracket via a pin. The connecting plate is hinged to both the lever crank and the fixing plate. The upper end of the lever is connected and fixed to the pin. The mounting bracket serves as a carrier to ensure stable cylinder assembly. The cylinder's drive shaft drives the fixing plate to slide back and forth along the radial direction of the needle in the needle assembly, causing the fixing plate to rotate one end of the connecting plate. This rotation is transmitted to the lever crank via the connecting plate, causing the lever crank to rotate back and forth on the mounting bracket. Finally, the pin drives the lever to swing, achieving the thread-picking action.

[0008] In the thread-shifting structure of the sewing machine described above, the mounting frame has two vertically arranged mounting plates. The lever crank is positioned between the two mounting plates, and the pin passes through both mounting plates. The lever crank is fixed to the outside of the pin, and the lever crank is respectively in contact with the sides of the two mounting plates. This arrangement allows the pin to rotate circumferentially using the two mounting plates, and the cooperation between the two mounting plates and the lever crank provides axial positioning of the pin, ensuring stable assembly of the shift lever.

[0009] In the thread-picking structure of the sewing machine described above, a locking hole is radially formed on the side wall of the pin, and the upper end of the lever is engaged in the locking hole. This ensures the stable assembly of the lever and the pin.

[0010] In the thread-pulling structure of the sewing machine described above, the lower end of the lever is continuously bent laterally to form the thread loop. This arrangement increases the force between the thread loop and the top thread, ensuring that a sufficient length of top thread can be pulled out when the lever swings.

[0011] Compared with existing technologies, the thread-picking structure of this sewing machine has the following advantages: the thread-picking lever is driven to swing by the cylinder and transmission components, and the thread-picking lever, electronic thread clamp and thread releaser work together to make the top thread in a flexed state between the electronic thread clamp and the thread releaser, ensuring that enough thread is left for the cutter and the thread clamp to clamp the thread end, and preventing the top thread end from being sewn onto the fabric and forming a bird's nest-like clump of thread when starting to sew. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the thread-picking mechanism of this sewing machine.

[0013] Figure 2 This is a structural diagram showing the assembly of the cylinder, mounting bracket, transmission components, and lever.

[0014] In the diagram, 1. Housing; 11. Needle assembly; 12. Thread releaser; 13. Mounting bracket; 131. Mounting plate; 2. Electronic thread clamp; 3. Lever; 31. Threading ring; 4. Cylinder; 5. Transmission assembly; 51. Lever crank; 52. Connecting plate; 53. Fixing plate; 6. Pin; 61. Snap-fit ​​hole. Detailed Implementation

[0015] 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.

[0016] like Figure 1 and Figure 2As shown, in the thread-picking structure of this sewing machine, the sewing machine includes a housing 1 and a needle assembly 11 that is slidably connected in the housing 1. The needle assembly 11 can specifically adopt existing technology, including a needle mounting rod and a needle, wherein the needle is fixed to the lower end of the needle mounting rod, and the needle is driven to move up and down by the needle mounting rod driven by the internal shaft of the housing 1.

[0017] A wire releaser 12 and an electronic wire clamp 2 are screwed and fixed to the outer wall of the housing 1. The two are located on the same outer wall of the housing 1 and are set near the bottom of the housing 1. The wire releaser 12 and the electronic wire clamp 2 are spaced apart, leaving sufficient space between them for the surface wire to be wired. It is worth mentioning that the connection between the wire releaser 12 and the electronic wire clamp 2 can adopt the existing technology. The specific structure and working method of the two will not be described in detail in this application.

[0018] like Figure 1 and Figure 2 As shown, a mounting bracket 13 is fixed to the top of the housing 1 by screws. The mounting bracket 13 has two vertically arranged mounting plates 131. The two mounting plates 131 are arranged opposite each other and protrude from the front of the housing 1. Each mounting plate 131 has a through hole. A lever 3 is provided vertically on the front of the housing 1, located at the upper end of the wire releaser 12 and the electronic wire clamp 2. The lower end of the lever 3 is bent horizontally to form a wire threading ring 31.

[0019] The mounting bracket 13 is equipped with a transmission assembly 5 and a cylinder 4. The cylinder 4 is arranged laterally and fixed to the mounting bracket 13 with screws, so that the driving end of the cylinder 4 is arranged radially along the needle assembly 11. The transmission assembly 5 specifically includes a lever crank 51, a connecting plate 52, and a fixing plate 53. The fixing plate 53 is an L-shaped plate and is fixed to the driving end of the cylinder 4. The lever crank 51 is placed between two mounting plates 131, with its two sides correspondingly attached to the two mounting plates 131. A pin 6 is provided between the two mounting plates 131 and passes through a through hole. The lever crank 51 is sleeved on the pin 6 and locked with a flat-head screw. The connecting plate 52 is long and narrow, with one end hinged to the fixing plate 53 and the other end hinged to the lever crank 51. A snap-fit ​​hole 61 is provided radially on the pin 6, and the upper end of the lever 3 is fixed in the snap-fit ​​hole 61 by interference fit.

[0020] Regarding the above structure, when the sewing machine is threading, the thread path is sequentially: thread releaser 12, thread loop 31 of lever 3, electronic thread clamp 2, and needle assembly 11. Simultaneously with sewing and thread cutting, the electronic thread clamp 2 closes, keeping the thread end positioned on the needle assembly 11. The lever 3 is driven by cylinder 4 to swing back and forth around the hinge, slightly pulling out the tail of the top thread. This leaves a sufficiently long section of top thread between the electronic thread clamp 2 and the thread releaser 12, which remains in a flexed state. When the remaining thread is cut and the next sewing operation is performed, the electronic thread clamp 2 opens (without cutting the top thread). (Clamping) The sewing machine needle goes down normally. Due to the presence of the bent thread, the cutter can drive the thread end of the thread to move synchronously and eventually be clamped by the thread clamping plate, ensuring that the thread end of the thread is in a taut state. This prevents the thread end from being sewn onto the fabric and forming a bird's nest-like clump of thread when starting to sew. In addition, it is worth mentioning that during the starting stage, after the sewing machine needle has sewn 1-3 stitches normally, the thread end will be cut off by the cutter while maintaining the stability of the stitch. In this state, the sewing machine is equipped with a suction device that can suck in air. The negative pressure generated by the suction will suck away the cut thread end, thus preventing the thread end from getting stuck.

[0021] 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.

[0022] Although this document frequently uses terms such as housing 1, needle assembly 11, thread releaser 12, mounting bracket 13, mounting plate 131, electronic thread clamp 2, lever 3, threading ring 31, cylinder 4, transmission assembly 5, lever crank 51, connecting plate 52, fixing plate 53, pin 6, and snap-fit ​​hole 61, the possibility of using other terms is not excluded. The use of these terms is merely for the convenience of describing and explaining the essence of this utility model; interpreting them as any additional limitation would contradict the spirit of this utility model.

Claims

1. A thread-release structure for a sewing machine, the sewing machine comprising a housing (1) internally slidably connected to a needle assembly (11) along a vertical direction, wherein a thread releaser (12) is fixed on the side wall of the housing (1), characterized in that, The wire-pulling structure includes an electronic wire clamp (2) fixed on the outer wall of the housing (1) and a lever (3) arranged vertically above the wire releaser (12) and the electronic wire clamp (2). The lower end of the lever (3) is bent to form a threading loop (31). The wire-pulling structure also includes a cylinder (4) fixed to the top of the housing (1). The drive shaft of the cylinder (4) is arranged radially along the needle assembly (11). The cylinder (4) is connected to the upper end of the lever (3) through a transmission assembly (5) and can drive the lower end of the lever (3) to swing closer to or away from the outer wall of the housing (1).

2. The thread-picking structure of the sewing machine according to claim 1, characterized in that, A mounting bracket (13) is fixed on the top outer wall of the housing (1). The cylinder (4) is fixed on the mounting bracket (13). The transmission assembly (5) includes a lever crank (51), a connecting plate (52), and a fixing plate (53). The fixing plate (53) is connected and fixed to the drive end of the cylinder (4). The lever crank (51) is rotatably connected to the mounting bracket (13) through a pin (6). The connecting plate (52) is hinged to the lever crank (51) and the fixing plate (53) respectively. The upper end of the lever (3) is connected and fixed to the pin (6).

3. The thread-picking structure of the sewing machine according to claim 2, characterized in that, The mounting bracket (13) has two vertically arranged mounting plates (131), the lever crank (51) is disposed between the two mounting plates (131), the pin (6) passes through the two mounting plates (131), the lever crank (51) is fixed to the outside of the pin (6), and the lever crank (51) is respectively attached to the side of the two mounting plates (131).

4. The thread-picking structure of the sewing machine according to claim 2 or 3, characterized in that, The pin (6) has a radially formed snap-fit ​​hole (61) on its side wall, and the upper end of the lever (3) is snapped into the snap-fit ​​hole (61).

5. The thread-picking structure of the sewing machine according to claim 4, characterized in that, The lower end of the lever (3) is continuously bent laterally to form the thread loop (31).

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