Automatic threading and twice reversing structure of sewing machine

Abstract

The utility model provides a kind of sewing machine automatic threading two-time reversing structure, belong to sewing machine technical field.It solves the problem of certain limitation of existing automatic threading device.This sewing machine needle bar assembly has limit seat, two-time reversing structure includes support, threading shaft, spring and steering column, the top of threading shaft is fixedly connected with guide pin, the bottom of threading shaft is equipped with threading chuck, support has the guide hole of inclined arrangement in it, one end of guide pin is arranged in guide hole, the top of steering column has the steering surface of inclined arrangement, steering surface is located above limit seat, when guide pin is down with threading shaft and support, the other end of guide pin can be moved along steering surface to make threading shaft rotate, threading shaft and support continue to move down to make guide pin abut on limit seat, support continues to move down to make guide pin relatively move upwards along guide hole to make threading shaft rotate.This sewing machine automatic threading two-time reversing structure has the advantage of improving the versatility of threading structure.

Description

Technical Field

[0001] This utility model belongs to the field of sewing machine technology and relates to an automatic threading and reversing structure for a sewing machine. Background Technology

[0002] A sewing machine is a mechanical device that uses one or more sewing threads to create specific stitches on materials (such as fabrics, leather, etc.), allowing one or more layers of material to interweave or sew together. When the thread breaks during sewing, it needs to be re-threaded through the eye of the needle. Because the eye of the needle is generally very fine, users cannot thread the thread through the eye of the needle quickly, especially the elderly or those with poor eyesight, requiring a significant amount of time to operate.

[0003] To address the aforementioned problems, various improvements have been made, some of which have even been patented. For example, Chinese patent literature discloses an automatic threader for sewing machines [Patent No.: 201310711324.1; Application Publication No.: CN103774356B]. This device includes a support frame, on which an automatic threading shaft and a needle bar are arranged in parallel. From top to bottom, a first mounting seat, a second mounting seat, and a third mounting seat are arranged on the support frame. The needle bar passes through the first and third mounting seats and can move axially. The automatic threading shaft passes through the second and third mounting seats and can move axially. A sewing needle is installed at the lower end of the needle bar. A transmission rod is sleeved on the automatic threading shaft, and a threading needle is fixedly connected to the lower end of the automatic threading shaft. A rotating mechanism is provided between the automatic threading shaft and the transmission rod, which enables the automatic threading shaft to rotate circumferentially and allows the threading needle to pass through the eye of the sewing needle.

[0004] This type of automatic threader can automatically thread the sewing machine after the thread breaks. However, the bottom of the sewing machine's presser bar is hinged to a presser foot via a foot rib. Changing the presser foot requires changing the foot rib to a different size and shape. This type of automatic threader has a limitation: when encountering a larger foot rib, the threading needle may hit the rib during rotation, preventing threading. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing an automatic threading structure for sewing machines with two-way reversal, thereby solving the technical problem of how to improve the versatility of the threading structure.

[0006] The objective of this utility model can be achieved through the following technical solution: an automatic threading and reversing structure for a sewing machine, the sewing machine including a needle bar assembly, the needle bar assembly having a limiting seat, the reversing structure including a bracket that can move up and down along the needle bar assembly, a threading shaft that can move up and down through the bracket, and a spring sleeved on the top of the threading shaft, a guide pin fixedly connected to the top of the threading shaft, a threading clamp provided at the bottom of the threading shaft, the bracket having an inclined guide hole, one end of the guide pin passing through the guide hole, and under the action of the spring force, one end of the guide pin always having a resistance. The tendency of the guide pin to rest against the bottom wall of the guide hole is characterized in that the two-way reversing structure further includes a steering column fixed to the needle bar assembly and arranged in a vertical direction. The top of the steering column has an inclined steering surface, which is located above the limiting seat. When the guide pin moves down with the threading shaft and the bracket, the other end of the guide pin can move along the steering surface to rotate the threading shaft. As the threading shaft and the bracket continue to move down, the guide pin can abut against the limiting seat. As the bracket continues to move down, the guide pin can move upward relative to the guide hole to rotate the threading shaft.

[0007] When a thread breaks and needs to be threaded, the needle bar assembly moves upward and resets. The support moves downward along the needle bar assembly, simultaneously driving the threading shaft and guide pin downward. This causes the other end of the guide pin to contact the turning surface. Because the guide hole at one end of the guide pin is angled, the guide pin can move along the turning surface, causing the threading shaft to rotate. This initial rotation of the threading shaft causes the threading clamp to rotate at a certain angle, preventing it from contacting the presser foot during further downward movement. This allows the automatic threading structure to be installed on different sewing machine models and to accommodate presser feet of different sizes and shapes, improving the versatility of the threading structure. As the threading shaft and support continue to move downward, the guide pin rests against the limit seat. At this point, the threading shaft stops moving downward. The support continues to move downward, and the guide pin moves upward along the guide hole, causing the threading shaft to rotate a second time, allowing the threading clamp to thread the thread.

[0008] In the aforementioned automatic threading and reversing structure of a sewing machine, the needle bar assembly includes a swing frame and a needle bar passing through the swing frame. A limiting seat protrudes from the center of the swing frame, and a positioning ring is formed by bending the bottom of the steering column. The needle bar passes through the positioning ring and is fixedly connected to it. The limiting seat is part of the swing frame, facilitating its manufacturing. The fixed connection between the steering column and the needle bar optimizes space utilization.

[0009] In the above-described automatic threading and reversing structure for a sewing machine, the limiting seat has a through limiting hole through which the threading shaft passes, with a clearance fit between the threading shaft and the wall of the limiting hole. The limiting hole of the limiting seat serves to limit and guide the threading shaft, ensuring smooth movement of the threading shaft, while also ensuring that the guide pin can abut against the limiting seat, realizing the second rotation of the threading shaft and enabling the threading clamp to thread the needle.

[0010] In the above-described automatic threading and reversing structure for a sewing machine, in the initial state, the other end of the guide pin is located directly above the turning surface. This structure ensures that the threading shaft can contact the turning surface after moving down, achieving the first reversal, avoiding the problem of collision between the threading clamp and the foot shank, and improving the versatility of the automatic threading structure.

[0011] In the above-described automatic threading and reversing structure for a sewing machine, one end of the spring acts on the bracket, and the other end acts on the guide pin. The spring causes the threading shaft to always have a downward tendency. This structure achieves elastic movement, ensures smooth movement of the threading shaft and guide pin, and improves the stability of the two-way reversing structure.

[0012] In the aforementioned automatic threading and reversing structure for a sewing machine, the reversing structure further includes a tension spring. One end of the tension spring acts on the swing frame, and the other end acts on the support. The tension spring ensures that the support always has an upward tendency. The tension spring serves a reset function, and the structure is simple.

[0013] Compared with the prior art, the automatic threading and two-way reversing structure for sewing machines provided by this utility model has the following advantages:

[0014] 1. This automatic threading system allows the threading shaft to change direction twice. The first change causes the threading clamp to rotate at a certain angle, preventing the threading clamp from hitting the foot rib during the downward movement. This allows the automatic threading structure to adapt to foot ribs and lifting feet of different sizes and shapes, improving the versatility of the automatic threading structure. The second change causes the threading clamp to rotate at a certain angle again to complete the threading.

[0015] 2. This two-way reversing structure achieves the first reversal of the wire clamp by setting an inclined reversing surface at the top of the reversing column, which is simple in structure. Attached Figure Description

[0016] Figure 1 This is an exploded view of the automatic threading structure with two reversal mechanisms.

[0017] Figure 2 This is a schematic diagram showing the position of the guide pin at the initial stage of this two-way reversal structure.

[0018] Figure 3This is a schematic diagram showing the position of the guide pin at the bottom of the guide hole at the initial stage of this two-way reversal structure.

[0019] Figure 4 This is the state diagram of the first commutation of this two-commutation structure.

[0020] Figure 5 This is a diagram showing the state of the guide pin of the two-way reversing structure when it abuts against the limit seat.

[0021] Figure 6 This is a schematic diagram showing the guide pin positioned at the top of the guide hole during the second reversal of this two-way reversal structure.

[0022] In the diagram, 1. Needle bar assembly; 11. Limiting seat; 12. Swing frame; 13. Needle bar; 14. Limiting hole; 2. Bracket; 21. Guide hole; 3. Threading shaft; 4. Spring; 5. Guide pin; 6. Threading clamp; 7. Steering column; 71. Steering surface; 72. Positioning ring; 8. Tension spring. Detailed Implementation

[0023] 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.

[0024] like Figure 1 As shown, the sewing machine includes a needle bar assembly 1 and an automatic threading two-way reversing structure. The needle bar assembly 1 includes a swing frame 12 and a needle bar 13. The automatic threading two-way reversing structure includes a bracket 2, a threading shaft 3, a spring 4, a guide pin 5, a threading clamp 6, a steering column 7, and a tension spring 8.

[0025] The needle bar 13 is inserted into the swing frame 12. The middle part of the swing frame 12 protrudes to form a limiting seat 11. The limiting seat 11 has a through limiting hole 14. The threading shaft 3 passes through the limiting hole 14 and is clearance-fitted with the hole wall of the limiting hole 14.

[0026] The bracket 2 is slidably connected to the swing frame 12, allowing the bracket 2 to move up and down along the swing frame 12. The threading shaft 3 is vertically movable and threaded through the bracket 2. A guide pin 5 is fixed to the top of the threading shaft 3, and a threading clamp 6 is located at the bottom. The bracket 2 has an inclined guide hole 21, with one end of the guide pin 5 passing through it. A spring 4 is fitted onto the top of the threading shaft 3, with one end acting on the bracket 2 and the other end on the guide pin 5. The spring 4 causes the threading shaft 3 to always have a downward tendency, and under the elastic force of the spring 4, one end of the guide pin 5 always tends to abut against the bottom wall of the guide hole 21. A tension spring 8 acts on one end of the swing frame 12 and the other end on the bracket 2, causing the bracket 2 to always have an upward tendency.

[0027] The steering column 7 is arranged vertically, and the top of the steering column 7 has an inclined steering surface 71, which is located above the limiting seat 11. The bottom of the steering column 7 is bent to form a positioning ring 72, and the needle bar 13 passes through the positioning ring 72 and is fixedly connected to the positioning ring 72.

[0028] like Figure 2 , Figure 3 As shown, in the initial state, the other end of the guide pin 5 is located directly above the turning surface 71, and one end of the guide pin 5 abuts against the bottom wall of the guide hole 21. When the sewing machine breaks the thread and needs to re-thread, the needle bar assembly 1 moves upward and resets, the bracket 2 moves downward along the needle bar assembly 1, and at the same time the bracket 2 moves downward, it drives the threading shaft 3 and the guide pin 5 to move downward synchronously, as shown. Figure 4 As shown, the other end of the guide pin 5 contacts the turning surface 71 and moves along the turning surface 71, causing the threading shaft 3 to rotate, thus achieving the first rotation of the threading shaft 3 and the first rotation of the threading clamp 6. Figure 5 As shown, the threading shaft 3 and the bracket 2 continue to move downwards, causing the guide pin 5 to abut against the limit seat 11, preventing the threading shaft 3 from moving further downwards. Figure 6 As shown, the bracket 2 continues to move downward, causing the guide pin 5 to move upward relative to the guide hole 21, thereby causing the threading shaft 3 to rotate, realizing the second rotation of the threading shaft 3, and enabling the threading clamp 6 to thread the wire.

[0029] 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.

[0030] Although this document frequently uses terms such as needle bar assembly 1, limiting seat 11, swing frame 12, needle bar 13, limiting hole 14, bracket 2, guide hole 21, threading shaft 3, spring 4, guide pin 5, threading clamp 6, steering column 7, steering surface 71, positioning ring 72, and tension spring 8, 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 two-stage automatic threading reversing structure for a sewing machine, the sewing machine including a needle bar assembly (1), the needle bar assembly (1) having a limiting seat (11), the two-stage reversing structure including a bracket (2) movable up and down along the needle bar assembly (1), a threading shaft (3) movable up and down and passing through the bracket (2), and a spring (4) sleeved on the top of the threading shaft (3), a guide pin (5) fixedly connected to the top of the threading shaft (3), a threading clamp (6) provided at the bottom of the threading shaft (3), the bracket (2) having an inclined guide hole (21), one end of the guide pin (5) passing through the guide hole (21), and under the action of the elastic force of the spring (4), one end of the guide pin (5) always having a tendency to abut against the bottom wall of the guide hole (21), characterized in that, The two-way reversing structure also includes a steering column (7) fixed to the needle bar assembly (1) and arranged in a vertical direction. The top of the steering column (7) has an inclined steering surface (71). The steering surface (71) is located above the limiting seat (11). When the guide pin (5) moves down with the threading shaft (3) and the bracket (2), the other end of the guide pin (5) can move along the steering surface (71) to rotate the threading shaft (3). The threading shaft (3) and the bracket (2) continue to move down to make the guide pin (5) abut against the limiting seat (11). The bracket (2) continues to move down to make the guide pin (5) move upward relative to the guide hole (21) to rotate the threading shaft (3).

2. The automatic threading and reversing structure for a sewing machine according to claim 1, characterized in that, The needle bar assembly (1) includes a swing frame (12) and a needle bar (13) passing through the swing frame (12). The middle part of the swing frame (12) protrudes to form the limiting seat (11). The bottom of the steering column (7) is bent to form a positioning ring (72). The needle bar (13) passes through the positioning ring (72) and the needle bar (13) is fixedly connected to the positioning ring (72).

3. The automatic threading and reversing structure for a sewing machine according to claim 2, characterized in that, The limiting seat (11) has a through limiting hole (14), the threading shaft (3) passes through the limiting hole (14), and the threading shaft (3) is clearance-fitted with the hole wall of the limiting hole (14).

4. A sewing machine automatic threading and reversing structure according to claim 1, 2, or 3, characterized in that, In the initial state, the other end of the guide pin (5) is located directly above the turning surface (71).

5. A sewing machine automatic threading and reversing structure according to claim 1, 2, or 3, characterized in that, One end of the spring (4) acts on the bracket (2), and the other end acts on the guide pin (5). The spring (4) causes the threading shaft (3) to always have a downward tendency.

6. A sewing machine automatic threading and reversing structure according to claim 1, 2, or 3, characterized in that, The two-way reversing structure also includes a tension spring (8), one end of which acts on the swing frame (12) and the other end of which acts on the support (2). The tension spring (8) makes the support (2) always have an upward tendency.

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