Pneumatic threading structure of a sewing machine
By incorporating the movable frame, lifting plate, and tension spring design in the pneumatic threading structure, the automatic engagement and disengagement of the thread feed tube and the looper are achieved, solving the problem of inconvenient threading operation in existing sewing machines and improving the ease of use and safety of the sewing machine.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 飞跃时代(浙江)科技有限公司
- Filing Date
- 2025-08-22
- Publication Date
- 2026-07-21
AI Technical Summary
The threading operation of existing sewing machines is inconvenient, especially since the position of the slide tube needs to be manually adjusted by the user, which makes them inconvenient to use.
It adopts a pneumatic threading structure, which utilizes the sliding cooperation of the moving frame and the support frame to achieve automatic engagement and disengagement of the thread feeding tube and the bending needle through the hinged lifting plate and the wrench. Combined with the elastic force of the tension spring, the operation process is simplified.
It improves the ease of use and safety of sewing machines, reduces the need for manual adjustment of the slide tube position during threading and sewing, and enhances the convenience and stability of operation.
Smart Images
Figure CN224531238U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of sewing machine technology and relates to a pneumatic threading structure for a sewing machine. Background Technology
[0002] Sewing machines are very common in modern life as fabric sewing devices. Among them, special sewing machines such as overlock sewing machines and coverstitch machines often require the use of looper structures to achieve specific and complex stitch strokes. It is worth mentioning that the looper is a common device in the sewing machine field. It is usually hollow and has a special shape compared to common machine needles. It is precisely because of the special structure of the looper that the preparation work for threading the needle often takes a lot of time.
[0003] To ensure convenient and labor-saving threading, pneumatic threading is a relatively mature method nowadays. For example, a Chinese patent (authorization announcement number: CN104928858B) discloses an overlock sewing machine that includes a main shaft fixed action arm and an arm capable of integrally swinging within a specified range. The main shaft fixed action arm is provided with a pin engagement part that engages with a fixed inner shaft pin, allowing the user to operate the arm. It also includes a main shaft fixed action spring, which, through the swinging motion of the main shaft fixed action arm and the arm, passes the neutral point, thereby switching the force direction to either direction of the swing. Furthermore, a switching cam ring is fixed on the main shaft fixed action shaft. The switching cam ring obtains driving force by abutting against a sliding plate pin of a sliding plate, and then rotates the main shaft fixed action shaft.
[0004] Combined with paragraphs 0204-0229 of the prior art and appendix Figure 1-6 As can be seen, the prior art uses a sliding plate as a carrier to assemble two sliding tubes. Specifically, the two sliding tubes are used for threading loops and, with the assistance of compressed air, can feed the loops into the corresponding insertion holes of the upper and lower loops. Based on this structure, while the thread feeding operation is in progress, the user can pull out or push in the main shaft fixing outer shaft (first shaft), thereby achieving the cooperation between the small diameter part of the main shaft fixing outer shaft (first shaft) and the long hole part on the sliding plate, or between the large diameter part of the main shaft fixing outer shaft (first shaft) and the wide hole part, so that the position of the sliding plate and the sliding tubes on the sliding plate can be maintained in the threading or sewing state.
[0005] However, in actual operation, when switching the positions of the two sliding tubes in the threading and sewing states, the user needs to first push the main shaft fixed outer shaft (first shaft) inward. Only when the small diameter part and the long hole part are aligned can the protruding knob be pushed to make the sliding plate drive the two sliding tubes to slide and the upper and lower loopers to separate. Conversely, the user needs to first pull the main shaft fixed outer shaft (first shaft) outward. Only when the large diameter part and the wide hole part are aligned can the protruding knob be pushed to make the sliding plate drive the two sliding tubes to slide and the upper and lower loopers to engage. The operation is particularly inconvenient. Summary of the Invention
[0006] The purpose of this utility model is to address the aforementioned problems in the existing technology by proposing a pneumatic threading structure for sewing machines. The technical problem to be solved by this utility model is: how to improve the ease of use of sewing machines.
[0007] The objective of this utility model can be achieved through the following technical solution: a pneumatic threading structure for a sewing machine, the sewing machine including a frame with a curved needle connected thereto, the pneumatic threading structure including a support frame fixed on the frame and a movable frame slidably connected in the support frame laterally, a thread feed tube fixed on the movable frame and disposed in the support frame, the movable frame being able to slide forward in the support frame to engage the thread feed tube and the curved needle or slide backward to separate the thread feed tube and the curved needle, characterized in that a lifting plate that can rotate vertically is hinged on the movable frame, the lifting plate being able to engage with the support frame to keep the movable frame in a fixed position after moving forward, a tension spring that elastically acts on the movable frame and can cause the movable frame to slide backward to return to its original position is connected to the support frame, and a wrench that can rotate laterally is also hinged on the movable frame, and the wrench can push the lifting plate to rotate upward around the hinge and separate from the support frame.
[0008] The working principle of the pneumatic threading structure of this sewing machine is as follows: the frame serves as a carrier to support the looper and support frame. A movable frame is slidably connected to the support frame. Utilizing the sliding engagement between the movable frame and the support frame, when the movable frame slides forward, the thread feed tube fixed on the movable frame and the looper on the frame are engaged. At this point, with the assistance of compressed air, the thread is fed through the thread feed tube into the looper, thus completing the threading operation. Conversely, when the movable frame slides backward, the thread feed tube fixed on the movable frame and the looper on the frame are separated, ensuring the safety of the sewing machine during sewing. Based on the above structure, this application differs from existing technologies in that: a lifting plate is hinged to the movable frame. When the movable frame slides forward, bringing the thread feed tube and looper into engagement, the lifting plate can be rotated vertically around the hinge point by a certain amplitude to lock and fix the lifting plate to the support frame. The lifting plate and support frame work together to ensure the moving frame remains positioned after sliding forward, thus guaranteeing the stability of the thread feed tube and looper engagement. A wrench is hinged to the moving frame, engaging with the lifting plate. This wrench rotates laterally and pushes the lifting plate around the hinge, separating the lifting plate from the support frame. Furthermore, a tension spring is installed on the support frame and connected to the moving frame. When the moving frame slides forward, the spring extends, generating an opposing elastic force that causes the moving frame to move backward and separate the thread feed tube and looper. In other words, when the user drives the lifting plate with the wrench, separating it from the support frame, the elastic force of the tension spring directly resets the moving frame, eliminating the need for unlocking and locking operations before and after adjustments, making the sewing machine more convenient to use.
[0009] In the pneumatic threading structure of the sewing machine described above, the support frame has a front opposing plate and a rear opposing plate arranged vertically. The front and rear opposing plates are arranged opposite each other horizontally. The movable frame is slidably connected between the front and rear opposing plates. The lifting plate is elongated and hook-shaped at the front end. The lifting plate is arranged horizontally and longitudinally, and its rear end is hinged to the movable frame. A retaining plate is fixed on the support frame near the front opposing plate, and the front end of the lifting plate engages with the retaining plate. Specifically, the support frame limits the sliding range of the movable frame through the cooperation of the front and rear opposing plates. The elongated lifting plate engages with the retaining plate near the front opposing plate on the support frame through its hook-shaped front end. When the movable frame slides closer to the front opposing plate, the front end of the lifting plate engages with the retaining plate, thereby achieving the engagement stability of the thread feed tube and the looper during threading.
[0010] In the pneumatic threading structure of the sewing machine described above, the upper outer wall of the front end of the lifting plate has a protrusion, and the moving frame has a plate-shaped limiting part with its side facing the end of the protrusion. The protrusion is fitted with a spring, and the spring elastically acts between the upper outer wall of the lifting plate and the limiting part. This design utilizes the elastic force of the spring to press the front end of the lifting plate against the upper outer wall of the lifting plate after it engages with the clamping plate. This prevents the lifting plate from moving up and down around the hinge during wire feeding, which could cause the front end of the lifting plate to separate from the clamping plate. It is worth mentioning that the disclosed lifting plate front end is hook-shaped, specifically with the hook facing downwards, and the front end of the lifting plate has a sloping structure. That is to say, when the moving frame is pushed forward, the front end of the lifting plate can engage with the upper edge of the clamping plate through the sloping surface, allowing the front end of the lifting plate to be gradually pushed upwards during the sliding process to create space. Then, after the sloping surface separates from the clamping plate, the elastic force of the spring pushes the front end of the lifting plate downwards to return to its original position, thereby achieving engagement with the clamping plate.
[0011] In the pneumatic threading structure of the sewing machine described above, a notch is provided on the lower side of the lifting plate near the middle, and the side wall of the notch near the front end of the lifting plate is inclined. The movable frame has a plate-shaped hinge that is bent away from the support frame. The wrench is a strip-shaped plate, and its middle part is hinged to the hinge. One end of the wrench extends into the notch and abuts against the side wall of the notch, while the other end protrudes from the free end of the hinge. When the operator turns the wrench, the front end of the wrench engages with the inclined side wall of the notch. Under force, the front end of the wrench continuously rotates against the inclined surface. The resulting deflection force causes the front end of the lifting plate to rotate around the hinge and gradually tilt upward, thereby unlocking the movable frame. Then, the movable frame can be pulled back to its original position by a tension spring.
[0012] In the pneumatic threading structure of the sewing machine described above, a through hole one is provided on the side wall near the bottom of the rear upright plate, and a through hole two is provided on the side wall near the bottom of the movable frame. One end of the tension spring is connected to the through hole one, and the other end is connected to the through hole two. This ensures that the tension spring is securely installed.
[0013] In the pneumatic threading structure of the sewing machine described above, a linkage switch is fixed on the support frame, and the detection end of the linkage switch abuts against the upper side of the limiting part. The linkage switch is a detection device that determines whether the moving frame has reached its reset position by having its detection end abut against the upper side of the limiting part. Only when the moving frame is in its reset position can the sewing machine perform pneumatic sewing operations, effectively ensuring safety.
[0014] In the pneumatic threading structure of the sewing machine described above, the movable frame includes a movable plate and a fixed plate, which are fixedly connected by screws. A fixed rod is fixed between the front and rear opposing plates. The movable plate is slidably connected to the outside of the fixed rod. The lifting plate is hinged to the fixed plate. The second through hole is formed on the fixed plate. The limiting part and the hinge part are both formed on the fixed plate. This design uses a separate movable plate and fixed plate to form the movable frame, thereby reducing the manufacturing difficulty and cost of the movable frame. By using the sliding connection between the movable plate and the fixed rod, the fixed plate can be moved back and forth between the front and rear opposing plates, thus achieving the purpose of joining or separating the thread feed tube and the bending needle. Furthermore, while the lifting plate is hinged to the fixed plate, the second through hole is formed on the fixed plate, and the limiting part and the hinge part are both formed on the fixed plate, thereby effectively utilizing space and ensuring a reasonable layout.
[0015] Compared with existing technologies, the pneumatic threading structure of this sewing machine has the following advantages: the lifting plate, which is hinged to the moving frame, engages with the support frame using its hook-shaped front end, so that the thread feed tube and the looper can be kept in the engaged state and maintained in position. The lifting plate is pushed to rotate around the hinge point and separate from the support frame by the wrench hinged to the moving frame, and the moving frame is pulled by the tension spring to slide back to separate the thread feed tube and the looper, ensuring that the operation of the sewing machine is more convenient. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the overall structure of the sewing machine.
[0017] Figure 2 This is a schematic diagram of the pneumatic threading structure of this sewing machine.
[0018] Figure 3 This is a schematic diagram of the pneumatic threading structure of this sewing machine after the support frame has been disassembled.
[0019] Figure 4 This is a schematic diagram of the pneumatic threading structure of this sewing machine after the support frame has been disassembled, from another perspective.
[0020] Figure 5 This is a structural diagram of the support frame.
[0021] Figure 6 This is a structural diagram of the mobile frame.
[0022] Figure 7 This is a schematic diagram of the lifting plate structure.
[0023] In the diagram, 1. Frame; 11. Bent pin; 2. Support frame; 21. Tension spring; 22. Front opposing plate; 23. Rear opposing plate; 231. Through hole one; 24. Clamping plate; 25. Interlocking switch; 3. Moving frame; 31. Cable feed tube; 32. Lifting plate; 321. Protrusion; 322. Notch; 33. Wrench; 34. Limiting part; 35. Hinge part; 36. Through hole two; 37. Moving plate; 38. Fixed plate; 4. Spring; 5. Fixed rod. Detailed Implementation
[0024] 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.
[0025] like Figure 1-4 As shown, in the pneumatic threading structure of this sewing machine, the sewing machine includes a frame 1, on which a looper 11 is installed. As prior art, the specific structure of the looper 11 will not be described in detail in this embodiment. As prior art, the number of loopers 11 is usually two or more. The sewing machine disclosed in this embodiment has two loopers 11 installed, namely an upper looper 11 and a lower looper 11.
[0026] A support frame 2 is fixed to the frame 1 by screws. The support frame 2 has a front opposing plate 22 and a rear opposing plate 23 arranged vertically. The front opposing plate 22 and the rear opposing plate 23 are arranged horizontally at intervals, so that a sliding adjustment space of a certain length is formed between the two opposing plates. Two fixing rods 5 are fixed between the front opposing plate 22 and the rear opposing plate 23. Both fixing rods 5 are arranged horizontally and are distributed vertically at intervals.
[0027] Combination Figure 5 A movable frame 3 is provided on the support frame 2 between the front opposing plate 22 and the rear opposing plate 23. Specifically, the movable frame 3 includes a movable plate 37 and a fixed plate 38 that are screwed together as one piece. The movable plate 37 is U-shaped, and through holes are provided on its two side plates corresponding to two fixed rods 5. The movable frame 3 is sleeved on the two fixed rods 5 through the two through holes and can drive the fixed plate 38 to slide between the front opposing plate 22 and the rear opposing plate 23 along the length of the fixed rods 5. It is worth mentioning that on the two side plates of the movable plate 37, Two corresponding through holes are provided on the surface of the front opposing plate 22 and the rear opposing plate 23. The diameter of the through hole on the moving plate 37 is smaller than that of the through holes on the front opposing plate 22 and the rear opposing plate 23. Two thread feeding tubes 31 for transmitting the sewing thread are inserted through the front opposing plate 22 and the rear opposing plate 23 and are snapped and fixed on the moving plate 37. The two thread feeding tubes 31 and the two bent needles 11 are joined or separated by the sliding of the moving plate 37 between the front opposing plate 22 and the rear opposing plate 23.
[0028] The fixed plate 38 is bent towards the side of the front opposing plate 22 to form a bent part. A through hole 36 is formed through the side wall of the bent part near the bottom. A through hole 231 is opened on the surface of the rear opposing plate 23. A tension spring 21 is provided in the support frame 2. One end of the tension spring 21 is connected to the through hole 231 and the other end is connected to the through hole 36, so that the tension spring 21 acts elastically between the rear opposing plate 23 and the fixed plate 38.
[0029] Combination Figure 6 and Figure 7 A long, narrow lifting plate 32 is hinged to the side of the fixed plate 38 facing the frame 1. The front end of the lifting plate 32 is hook-shaped, and a limit opening is vertically formed at the top of the bent portion. The front end of the lifting plate 32 is inserted into the limit opening and abuts against the bottom wall of the limit block. A clamping plate 24 is provided on the support frame 2. The clamping plate 24 is fixed to the support frame 2 by screws and is located near the front opposing plate 22. A protrusion 321 is provided on the upper side of the front end of the lifting plate 32. A limit portion 34 is provided on the top of the fixed plate 38, which is bent towards the frame 1 and whose lower side is directly opposite the upper end of the protrusion 321. A spring 4 is sleeved on the protrusion 321. One end of the spring 4 abuts against the upper side of the front end of the lifting plate 32, and the other end abuts against the lower side of the protrusion 321.
[0030] A notch 322 is provided on the lower side of the lifting plate 32 near the middle, and the side wall of the notch 322 near the front upright plate 22 is inclined. A hinge portion 35 is bent away from the frame 1 at the top of the fixing plate 38. A wrench 33 is hinged to the hinge portion 35. Specifically, the middle of the wrench 33 is hinged to the hinge portion 35 via a pin. One end of the wrench 33 extends into the notch 322 and abuts against the inclined side wall of the notch 322, while the other end of the wrench 33 protrudes from the free end of the hinge portion 35. Furthermore, a linkage switch 25 is fixed on the frame 1, and the detection end of the linkage switch 25 abuts against the upper side of the limiting portion 34.
[0031] Working principle: When threading is required, the operator pushes the moving plate 37, causing the entire moving frame 3 to slide forward towards the opposing plate 22 until the front end of the lifting plate 32 contacts the clamping plate 24. Under the continuous pushing force, the lifting plate 32 rotates around the hinge, causing the front end to lift upward. After the front end passes the clamping plate 24, it engages with the clamping plate 24, thus keeping the entire moving frame 3 in a position close to or against the front opposing plate 22. At this time, the moving plate 37 drives the wire feeding tube 31 through the front opposing plate 22 and engages with the bent needle 11. Conversely, after the threading operation is completed, the operator pulls the wrench 33 backward, causing the front end of the wrench 33 and the beveled side wall of the notch 322 to push the lifting plate 32 upward around the hinge. In this state, the front end of the lifting plate 32 separates from the clamping plate 24, and under the elastic action of the tension spring 21, it pulls the moving plate 37 backward. The upright plate 23 slides back to its original position. When the operator releases the wrench 33, the previously compressed spring 4 pushes the front end of the lifting plate 32 downward to rotate back to its original position with the limit part 34 as the fulcrum. The lifting plate 32 also pushes the wrench 33 to rotate back to its original position around the hinge. In this state, the moving plate 37 drives the thread feed tube 31 to retract backward, causing the thread feed tube 31 and the bent needle 11 to separate. It is worth mentioning that after the separation of the thread feed tube 31 and the bent needle 11 is completed, it means that the sewing machine can start sewing normally. In this embodiment, in order to fully ensure safety, a linkage switch 25 is separately installed on the support frame 2, and the detection end of the linkage switch 25 abuts against the upper side of the limit part 34 after the moving frame 3 completes its reset, thereby achieving the detection of the overall position of the moving frame 3, ensuring that the operator can effectively confirm the reset status of the moving frame 3, and thus ensuring the safety of subsequent sewing work.
[0032] 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.
[0033] Although this document frequently uses terms such as frame 1, bent needle 11, support frame 2, tension spring 21, front opposing plate 22, rear opposing plate 23, through hole one 231, clamping plate 24, linkage switch 25, moving frame 3, wire feeding tube 31, lifting plate 32, protrusion 321, notch 322, wrench 33, limiting part 34, hinge part 35, through hole two 36, moving plate 37, fixing plate 38, spring 4, and fixing rod 5, 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 pneumatic threading structure for a sewing machine, the sewing machine including a frame (1) connected with a looper (11), the pneumatic threading structure including a support frame (2) fixed on the frame (1) and a movable frame (3) slidably connected in the support frame (2) laterally, a thread feed tube (31) fixed on the movable frame (3) and disposed therethrough in the support frame (2), the movable frame (3) being capable of sliding forward in the support frame (2) to engage the thread feed tube (31) and the looper (11) or sliding backward to separate the thread feed tube (31) and the looper (11), characterized in that, The movable frame (3) is hinged with a lifting plate (32) that can rotate vertically. The lifting plate (32) can be fastened to the support frame (2) so that the movable frame (3) can move forward and remain in position. The support frame (2) is connected with a tension spring (21) that acts elastically on the movable frame (3) and can make the movable frame (3) slide back to reset. The movable frame (3) is also hinged with a wrench (33) that can rotate horizontally. The wrench (33) can push the lifting plate (32) to rotate upward around the hinge and separate from the support frame (2).
2. The pneumatic threading structure of the sewing machine according to claim 1, characterized in that, The support frame (2) has a front opposing plate (22) and a rear opposing plate (23) arranged vertically. The front opposing plate (22) and the rear opposing plate (23) are arranged opposite each other in the transverse direction. The movable frame (3) is slidably connected between the front opposing plate (22) and the rear opposing plate (23). The lifting plate (32) is long and has a hook-shaped front end. The lifting plate (32) is arranged horizontally and longitudinally and its rear end is hinged to the movable frame (3). A clamping plate (24) is fixed on the support frame (2) near the front opposing plate (22). The front end of the lifting plate (32) is engaged with the clamping plate (24).
3. The pneumatic threading structure of the sewing machine according to claim 2, characterized in that, The upper outer wall of the lifting plate (32) has a protrusion (321), and the moving frame (3) has a plate-shaped limiting part (34) that is directly opposite the side of the protrusion (321). The protrusion (321) is covered with a spring (4), and the spring (4) acts elastically between the upper outer wall of the lifting plate (32) and the limiting part (34).
4. The pneumatic threading structure of the sewing machine according to claim 3, characterized in that, The lower side of the lifting plate (32) near the middle is provided with a notch (322), and the side wall of the notch (322) near the front end of the lifting plate (32) is inclined. The movable frame (3) has a plate-shaped hinge part (35) that is bent away from the support frame (2). The wrench (33) is a strip plate. The middle part of the wrench (33) is hinged to the hinge part (35). One end of the wrench (33) extends into the notch (322) and abuts against the side wall of the notch (322). The other end protrudes from the free end of the hinge part (35).
5. The pneumatic threading structure of the sewing machine according to claim 4, characterized in that, The rear opposing plate (23) has a through hole 1 (231) on its side wall near the bottom, and the movable frame (3) has a through hole 2 (36) on its side wall near the bottom. One end of the tension spring (21) is connected to the through hole 1 (231), and the other end is connected to the through hole 2 (36).
6. The pneumatic threading structure of the sewing machine according to claim 3, characterized in that, A linkage switch (25) is fixed on the support frame (2), and the detection end of the linkage switch (25) abuts against the upper side of the limiting part (34).
7. The pneumatic threading structure of the sewing machine according to claim 5, characterized in that, The movable frame (3) includes a movable plate (37) and a fixed plate (38). The movable plate (37) and the fixed plate (38) are fixed together by screws. A fixed rod (5) is fixed between the front opposing plate (22) and the rear opposing plate (23). The movable plate (37) is slidably connected to the outside of the fixed rod (5). The lifting plate (32) is hinged to the fixed plate (38). The second through hole (36) is opened on the fixed plate (38). The limiting part (34) and the hinge part (35) are both formed on the fixed plate (38).