Automatic thread trimming mechanism after bobbin bottom thread winding and sewing machine
By designing an automatic thread cutting mechanism after the bobbin bottom thread is wound, the winding handle is used to drive the movable knife to rotate and the positioning mechanism is used to limit the bottom thread, so that the bottom thread is automatically cut, which solves the problem of wasting time by manual cutting and improves the winding efficiency.
Patent Information
- Application Number
- CN202510879715.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-27
- Publication Date
- 2025-09-19
AI Technical Summary
In the prior art, the bobbin bottom thread needs to be cut manually after being wound, which wastes time and affects work efficiency.
A mechanism for automatically cutting the bobbin thread after winding the bobbin bottom thread is designed. The winding handle drives the movable knife to rotate and is restricted by a positioning mechanism to automatically cut the bottom thread. The mechanism includes the cooperation of the fixed knife, the movable knife, the positioning mechanism and the elastic reset element.
When the bobbin is fully wound, it can automatically cut the bobbin, reducing manual operations, improving winding efficiency and saving time.
Smart Images
Figure CN120666507A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of sewing equipment, and in particular relates to an automatic thread trimming mechanism after bobbin bottom thread is wound and a sewing machine. Background Art
[0002] The rotary hook is a crucial component of a sewing machine's thread-retrieving mechanism. A lockstitch is composed of an upper thread and a lower thread. The upper thread passes through the thread tensioner, thread take-up lever, and thread hook, ultimately passing through the needle. The lower thread is wound around the circular bobbin to a desired length, then mounted on the bobbin case. The bobbin case then fits into the rotary hook. When the bobbin's lower thread is exhausted, the bobbin is removed and rewound with thread. The rotary hook is then reinstalled and used again. The currently existing bobbin thread winding mechanism is a bobbin winder winding mechanism, that is, after the bobbin is installed on the bobbin winder, the bobbin thread is partially wound on the bobbin first. When the handle of the bobbin winder is turned, the bobbin will rotate driven by the main shaft, and the bobbin thread will automatically be wound onto the bobbin. When the bobbin thread is fully wound, the handle of the bobbin winder will automatically pop up to stop winding. At this time, it is necessary to manually cut the bobbin thread connected to the bobbin and then take the bobbin out for use. Since the bobbin thread needs to be rewound about 20 minutes in actual use, workers need to frequently replace the bobbin thread during use, which requires frequent cutting of the bobbin thread, which greatly wastes time. Summary of the Invention
[0003] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a mechanism and a sewing machine that automatically cuts the bobbin thread after winding the bobbin bottom thread, so as to solve the problem in the prior art that the bobbin bottom thread needs to be manually cut after winding the bobbin bottom thread, resulting in a waste of time and affecting work efficiency.
[0004] In order to achieve the above-mentioned purpose and other related purposes, one aspect of the present invention provides a mechanism for automatically trimming the thread after the bobbin bottom thread is wound, comprising a sewing machine head, a bobbin winder being provided on the sewing machine head, the bobbin winder comprising a bobbin winding handle, the bobbin winding handle being rotatable, and when the bobbin is fully wound with the bottom thread, the bobbin winding handle will be rebounded from the working position to the initial position, and further comprising a fixed knife, a movable knife and a positioning mechanism, wherein the fixed knife is fixedly provided on the sewing machine head, the movable knife is rotatably provided on the sewing machine head, and a first elastic reset element is provided on the movable knife; based on the rotation of the bobbin winding handle from the initial position When the movable knife reaches the working position, the winding handle can drive the movable knife to rotate from the first position to the second position. When the movable knife is in the second position, the positioning mechanism can limit the movable knife from resetting to the first position. When the movable knife is in the first position, the movable knife is closed relative to the fixed knife, and when the movable knife is in the second position, the movable knife is opened relative to the fixed knife. When the winding handle rebounds to the initial position, the winding handle can release the restriction of the positioning mechanism on the movable knife, so that the movable knife is reset to the first position based on the elastic force of the first elastic reset element.
[0005] Furthermore, the positioning mechanism includes a positioning column and a limiting rod, wherein the positioning column is hinged to the sewing machine head, and a second elastic reset element is provided between the positioning column and the sewing machine head. When the movable knife rotates from the first position to the second position, the movable knife can press down the positioning column to swing in the first direction, and when the movable knife rotates from the second position to the first position, the movable knife can press down the positioning column to swing in the second direction; the limiting rod is movably provided on the sewing machine head and is located in the second direction of the positioning column, the first end of the limiting rod is in conflict with one side of the positioning column, and a third elastic reset element is sandwiched between the second end of the limiting rod and the sewing machine head; the elastic force of the first elastic reset element when the movable knife is in the second position is greater than the compressible force of the second elastic reset element and less than or equal to the compressible force of the third elastic reset element; when the winding handle rebounds from the working position to the initial position, the winding handle can drive the limiting rod to compress the third elastic reset element, so that the first end of the limiting rod is away from the positioning column.
[0006] Furthermore, the first elastic reset element is a torsion spring, one end of the torsion spring is connected to the movable knife, and the other end of the torsion spring is connected to the sewing machine head.
[0007] Furthermore, the second elastic reset element includes a second spring, and the third elastic reset element includes a third spring.
[0008] Furthermore, a slide is provided on the sewing machine head, the limiting rod is slidably arranged on the slide, and the third elastic reset element is clamped between the second end of the limiting rod and the slide.
[0009] Furthermore, the slide seat includes a base plate and a vertical plate arranged on the base plate, the vertical plate is provided with a guide rod extending along the axial direction of the limit rod, the second end of the limit rod is a hollow structure, the limit rod is slidably mounted on the guide rod through the hollow structure, and the third elastic reset element is clamped between the vertical plate and the second end of the limit rod.
[0010] Furthermore, the limiting rod is provided with a lug extending toward the winding handle, and when the winding handle rebounds from the working position to the initial position, the winding handle contacts the lug.
[0011] Furthermore, a connecting column extending upward is fixedly provided on the sewing machine head, and the middle part of the movable knife is rotatably connected to the connecting column.
[0012] As described above, the automatic thread trimming mechanism after the bobbin bottom line is wound on the present invention has the following beneficial effects: when no winding is being performed, the winding handle on the winder is in the initial position; when winding is required, the winding handle is manually rotated to rotate it from the initial position to the working position; during the manual rotation of the winding handle, the winding handle can come into contact with the movable knife, thereby driving the movable knife to rotate together, that is, after the winding handle is rotated from the initial position to the working position, the winding handle can drive the movable knife to rotate from the first position to the second position, that is, to rotate the movable knife from the closed state relative to the fixed knife to the open state relative to the fixed knife. When the bobbin is fully wound with the bottom thread, the bobbin winding handle 1 can automatically rebound from the working position to the initial position. During this process, the bobbin winding handle 1 can release the restriction of the positioning mechanism on the movable knife, and thus the movable knife can be reset to the first position based on the elastic force of the first elastic reset element, that is, the movable knife is closed relative to the fixed knife to cut the thread, and then the bottom thread can be automatically cut immediately after the bottom thread is fully wound, and there is no need for manual frequent thread cutting with scissors, thereby greatly improving the efficiency of bottom thread winding and saving time of bottom thread winding.
[0013] Another aspect of the present invention provides a sewing machine including the above-mentioned automatic thread trimming mechanism after bobbin bobbin thread winding. The beneficial effects of the sewing machine are the same as those of the above-mentioned automatic thread trimming mechanism after bobbin bobbin thread winding, so they will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1The figure shows a schematic diagram of the automatic thread trimming mechanism of the present invention in an open state after the bobbin bottom thread is wound.
[0015] Figure 2 The present invention provides Figure 1 Enlarged view of point A in the middle.
[0016] Figure 3 The figure shows the automatic thread trimming mechanism provided by the present invention in a thread trimming state after the bobbin bottom thread is wound.
[0017] Figure 4 The present invention provides Figure 3 Enlarged view of point B in the middle.
[0018] Description of Reference Numerals
[0019] 10 Fixed Knife
[0020] 20 Operation
[0021] 201 Torsion Spring
[0022] 30 Positioning mechanism
[0023] 31 Positioning column
[0024] 311 Second Spring
[0025] 32 limit rod
[0026] 321 Third Spring
[0027] 322 lugs
[0028] 40 Slide
[0029] 41 bottom plate
[0030] 42 vertical board
[0031] 100 Sewing machine head
[0032] 101 Winder
[0033] 1011 Rotating Handle DETAILED DESCRIPTION
[0034] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.
[0035] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed or detachable connections, or integral connections; mechanical or electrical connections; direct connections or connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.
[0036] In the description of the present invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc. used in the present invention to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.
[0037] See also Figures 1 to 4 It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.
[0038] The first aspect of the present invention provides a mechanism for automatically trimming the bobbin thread after winding the bobbin thread. Figures 1 to 4 As shown, the automatic thread trimming mechanism includes a sewing machine head 100, and a bobbin winder 101 is provided on the sewing machine head 100. The bobbin winder 101 includes a winding handle 1011. The winding handle 1011 can be rotated. When the bobbin is fully wound with the bottom line, the winding handle 1011 will be moved from the working position ( Figure 1 and Figure 2 shown position) rebounds to the initial position ( Figure 3 and Figure 4 The present invention also includes a fixed knife 10, a movable knife 20 and a positioning mechanism 30, wherein the fixed knife 10 is fixedly arranged on the sewing machine head 100, and the movable knife 20 is rotatably arranged on the sewing machine head 100, and a first elastic reset element is provided on the movable knife 20. When winding, based on rotating the winding handle 1011 from the initial position to the working position, the winding handle 1011 can drive the movable knife 20 from the first position ( Figure 3 and 4 shown position) to the second position ( Figure 1 and Figure 2 The movable knife 20 is in the first position and is closed relative to the fixed knife 10 when the movable knife 20 is in the first position, and is opened relative to the fixed knife 10 when the movable knife 20 is in the second position; when the bobbin is fully wound with thread, the winding handle 1011 automatically rebounds from the working position to the initial position, and the winding handle 1011 can release the restriction of the movable knife 20 by the positioning mechanism 30, so that the movable knife 20 is reset to the first position based on the elastic force of the first elastic reset element, that is, the movable knife 20 and the fixed knife 10 are closed to cut the thread.
[0039] The beneficial effect of the automatic thread trimming mechanism after the bobbin bottom line is wound is that when the bobbin is not wound, the winding handle 1011 on the winder 101 is in the position as shown in FIG. Figure 3 and Figure 4 When winding is required, the winding handle 1011 is manually rotated from the initial position to the position shown in FIG. Figure 1 and Figure 2 In the working position shown, when the winding handle 1011 is manually rotated, the winding handle 1011 can conflict with the movable knife 20, thereby driving the movable knife 20 to rotate together, that is, after the winding handle 1011 is rotated from the initial position to the working position, the winding handle 1011 can drive the movable knife 20 from the first position ( Figure 3 and Figure 4 position shown) to the second position ( Figure 1 and Figure 2 The bobbin 10 is then freed from the engagement of the thread cutter 20 with the thread being cut, and the thread being cut is brought back to the original position by the thread cutter 20. The thread is then cut back to the original position by the thread cutter 20.
[0040] Further, if Figure 2 As shown, in this embodiment, the first elastic reset element is a torsion spring 201, one end of the torsion spring 201 is connected to the movable knife 20, and the other end of the torsion spring 201 is connected to the sewing machine head 100. The structure is simple and the cost is low.
[0041] Further, if Figure 2 As shown, in this embodiment, a connecting post 102 extending upward is fixedly provided on the sewing machine head 100 , and the middle portion of the movable knife 20 is rotatably connected to the connecting post 102 .
[0042] Further, if Figure 2 and Figure 4 As shown, in this embodiment, the positioning mechanism 30 includes a positioning post 31 and a limiting rod 32, wherein the positioning post 31 is hinged on the sewing machine head 100, and a second elastic reset element is provided between the positioning post 31 and the sewing machine head 100. When the movable knife 20 rotates from the first position to the second position, the movable knife 20 can press down the positioning post 31 to swing in the first direction. As the positioning post 31 swings downward, the movable knife 20 can pass over the positioning post 31. After the movable knife 20 presses down the positioning post 31 to pass over it, due to the action of the second elastic reset element, the positioning post 31 can automatically reset upward. When the movable knife 20 rotates from the second position to the first position, the movable knife 20 can press down the positioning post 31 to swing in the second direction. Similarly, when the movable knife 20 presses down the positioning post 31 to pass from its After passing through the top, the positioning column 31 can automatically reset upwards through the action of the second elastic reset element. The limit rod 32 is movably arranged on the sewing machine head 100, and the limit rod 32 is located in the second direction of the positioning column 31. The first end of the limit rod 32 conflicts with one side of the positioning column 31. A third elastic reset element is sandwiched between the second end of the limit rod 32 and the sewing machine head 100. Specifically, when the movable knife 20 is in the second position, the elastic force of the first elastic reset element is greater than the force that the second elastic reset element can be compressed, and is less than or equal to the force that the third elastic reset element can be compressed. When the winding handle 1011 rebounds from the working position to the initial position, the winding handle 1011 can drive the limit rod 32 to compress the third elastic reset element, so that the first end of the limit rod 32 is away from the positioning column 31. With this arrangement, when winding is to be performed, the movable knife 20 is driven by the winding handle 1011 to rotate to the second position (such as Figure 2The movable knife 20 is in an open state relative to the fixed knife 10. At this time, the first elastic reset element, i.e., the torsion spring 201, on the movable knife 20 is in an energy storage state. The elastic potential energy stored in the torsion spring 201 can make the movable knife 20 rotate back and reset to the first position. However, since a limiting rod 32 is provided in the second direction of the positioning post 31 at this time, the first end of the limiting rod 32 conflicts with the positioning post 31, and the third elastic reset element provided at the second end of the limiting rod 32 can be compressed with a force greater than the elastic force stored in the first elastic reset element, i.e., the torsion spring 201, when the movable knife 20 is in the second position. That is, the elastic force of the torsion spring 201 is not enough to compress the third elastic reset element and the limiting rod 32. Therefore, the limiting rod 32 can support the positioning post 31 to limit it, so that the positioning post 31 remains stationary, i.e., prevent it from being pressed down in the second direction, thereby The movable knife 20 can be restricted from resetting from the second position to the first position, and normal winding operation can be performed in this state. When the bobbin is fully wound with the bottom line, the winding handle 1011 rebounds from the working position to the initial position. Since the winding handle 1011 can drive the limiting rod 32 to compress the third elastic reset element, the first end of the limiting rod 32 is away from the positioning column 31, so that the positioning column 31 lacks the support and limit of the limiting rod 32. Since the elastic force stored by the first elastic reset element, i.e., the torsion spring 201, when the movable knife 20 is in the second position is greater than the force that can be compressed by the second elastic reset element, when the limiting rod 32 is away from the positioning column 31, the movable knife 20 will press down the positioning column 31 based on the elastic force stored by the torsion spring 201 and pass through it to reset to the first position, i.e., cooperate with the fixed knife 10 to cut the thread, thereby realizing the automatic thread cutting action. In summary, the structure is simple and the design is ingenious.
[0043] Furthermore, in this embodiment, the second elastic reset element includes a second spring 311, and the third elastic reset element includes a third spring 321. That is, in this embodiment, the second elastic reset element and the third elastic reset element are both springs, which has a simple structure and low cost. Preferably, in order to improve the performance and stability of the automatic reset of the positioning column 31, as shown in FIG. Figure 2 As shown, in this embodiment, second springs 311 are provided in both the first direction and the second direction of the positioning column 31 .
[0044] Further, if Figure 2 As shown, in this embodiment, a slide 40 is provided on the sewing machine head 100, a limiting rod 32 is slidably set on the slide 40, and a third elastic reset element, i.e., a third spring 321, is clamped between the second end of the limiting rod 32 and the slide 40.
[0045] Specifically, such as Figure 2As shown, in this embodiment, the slide 40 includes a base plate 41 and a vertical plate 42 disposed on the base plate 41. The vertical plate 42 is provided with a guide rod extending in the axial direction of the limiting rod 32. Accordingly, the second end of the limiting rod 32 is a hollow structure, and the limiting rod 32 is slidably mounted on the guide rod through the hollow structure. The third elastic return element, i.e., the third spring 321, is mounted on the guide rod and sandwiched between the vertical plate 42 and the second end of the limiting rod 32. This arrangement, i.e., the sliding connection of the limiting rod 32 by mounting it on the guide rod, has a simple structure and high stability.
[0046] Further, if Figure 2 and Figure 4 As shown, the limiting rod 32 is provided with a lug 322 extending toward the winding handle 1011. When the winding handle 1011 rebounds from the working position to the initial position, the winding handle 1011 conflicts with the lug 322 on the limiting rod 32, that is, when the winding handle 1011 rebounds, the winding handle 1011 conflicts with the lug 322 to drive the limiting rod 32 to move together.
[0047] Another aspect of the present invention provides a sewing machine including the above-mentioned automatic thread trimming mechanism after bobbin bobbin thread winding. The beneficial effects of the sewing machine are the same as those of the above-mentioned automatic thread trimming mechanism after bobbin bobbin thread winding, so they will not be described in detail here.
[0048] In summary, the present invention's automatic bobbin thread trimming mechanism and sewing machine automatically cut the bobbin thread immediately after it is fully wound, eliminating the need for frequent manual thread trimming with scissors. This significantly improves bobbin thread winding efficiency and saves time. Furthermore, the mechanism is applicable to all lockstitch sewing machines. Therefore, the present invention effectively overcomes the shortcomings of the prior art and possesses high industrial value.
[0049] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.
Claims
1. A mechanism for automatically trimming a bobbin thread after winding the bobbin thread, comprising a sewing machine head (100), a bobbin winder (101) being provided on the sewing machine head (100), the bobbin winder (101) comprising a bobbin winding handle (1011), the bobbin winding handle (1011) being rotatable, and when the bobbin thread is fully wound with the bobbin thread, the bobbin winding handle (1011) is rebounded from a working position to an initial position, characterized in that: The invention comprises a fixed knife (10), a movable knife (20) and a positioning mechanism (30), wherein the fixed knife (10) is fixedly arranged on the sewing machine head (100), the movable knife (20) is rotatably arranged on the sewing machine head (100), and the movable knife (20) is provided with a first elastic reset element; Based on the winding handle (1011) rotating from the initial position to the working position, the winding handle (100) can drive the movable knife (20) to rotate from the first position to the second position, and when the movable knife (20) is in the second position, the positioning mechanism (30) can limit the movable knife (20) from returning to the first position; wherein, when the movable knife (20) is in the first position, the movable knife (20) is closed relative to the fixed knife (10), and when the movable knife (20) is in the second position, the movable knife (20) is opened relative to the fixed knife (10); When the winding handle (1011) rebounds to the initial position, the winding handle (1011) can release the restriction of the positioning mechanism (30) on the movable knife (20), so that the movable knife (20) is reset to the first position based on the elastic force of the first elastic reset element.
2. The automatic thread trimming mechanism after bobbin lower thread winding according to claim 1, characterized in that: The positioning mechanism (30) includes a positioning column (31) and a limiting rod (32), wherein the positioning column (31) is hinged to the sewing machine head (100), and a second elastic reset element is provided between the positioning column (31) and the sewing machine head (100); when the movable knife (20) rotates from the first position to the second position, the movable knife (20) can press down the positioning column (31) to swing in the first direction; when the movable knife (20) rotates from the second position to the first position, the movable knife (20) can press down the positioning column (31) to swing in the second direction; the limiting rod (32) is movably provided on the sewing machine head and is located between the positioning column (31) and the sewing machine head (100); ), the first end of the limiting rod (32) contacts one side of the positioning column (31), and a third elastic reset element is sandwiched between the second end of the limiting rod (32) and the sewing machine head; when the movable knife (20) is in the second position, the elastic force of the first elastic reset element is greater than the force that the second elastic reset element can be compressed, and is less than or equal to the force that the third elastic reset element can be compressed; when the winding handle (1011) rebounds from the working position to the initial position, the winding handle can drive the limiting rod (32) to compress the third elastic reset element, so that the first end of the limiting rod (32) is away from the positioning column (31).
3. The automatic thread trimming mechanism after bobbin bottom thread winding according to claim 1, characterized in that: The first elastic reset element is a torsion spring (201), one end of the torsion spring (201) is connected to the movable knife (20), and the other end of the torsion spring (201) is connected to the sewing machine head (100).
4. The automatic thread trimming mechanism after bobbin lower thread winding according to claim 2, characterized in that: The second elastic reset element includes a second spring (311), and the third elastic reset element includes a third spring (321).
5. The automatic thread trimming mechanism after bobbin lower thread winding according to claim 2, characterized in that: A slide seat (40) is provided on the sewing machine head (100), the limiting rod (32) is slidably arranged on the slide seat (40), and the third elastic reset element is clamped between the second end of the limiting rod (32) and the slide seat (40).
6. The automatic thread trimming mechanism after bobbin lower thread winding according to claim 5, characterized in that: The slide seat (40) includes a base plate (41) and a vertical plate (42) arranged on the base plate (41); the vertical plate (42) is provided with a guide rod extending along the axial direction of the limit rod (32); the second end of the limit rod (32) is a hollow structure, and the limit rod (32) is slidably mounted on the guide rod through the hollow structure; the third elastic reset element is clamped between the vertical plate (42) and the second end of the limit rod (32).
7. The automatic thread trimming mechanism after bobbin lower thread winding according to claim 2, characterized in that: The limiting rod (32) is provided with a lug (322) extending in a direction close to the winding handle (1011), and when the winding handle (1011) rebounds from the working position to the initial position, the winding handle (1011) contacts the lug (322).
8. The automatic thread trimming mechanism after bobbin lower thread winding according to claim 1, characterized in that: An upwardly extending connecting column (102) is fixedly provided on the sewing machine head (1011), and the middle part of the movable knife (20) is rotatably connected to the connecting column (102).
9. A sewing machine, characterized in that: The sewing machine comprises the automatic thread trimming mechanism after the bobbin bottom thread is wound as claimed in any one of claims 1 to 8.