Thread trimming mechanism capable of reducing bird nest problem and sewing machine

Abstract

The utility model relates to a trimming mechanism capable of reducing bird nest problem and a sewing machine, the trimming mechanism comprises a first trimming knife, a second trimming knife and a bottom thread catching piece, the second trimming knife is provided with a trimming hook, the bottom thread catching piece comprises an arc-shaped catching piece arranged along the peripheral side of a rotating shuttle, and the arc-shaped catching piece is connected with the trimming hook. The arc-shaped catching piece is located between the rotating shuttle and the first thread trimmer, a first catching part is arranged on the side face, facing the rotating shuttle, of the first thread trimmer, and a second catching part matched with the first catching part is arranged on the outer arc face of the arc-shaped catching piece. When the thread is trimmed, the second thread trimmer rotates towards the first thread trimmer and enables the thread trimming hook to drive the bottom thread to extend between the first catching part and the second catching part, and the first catching part is provided with a first concave structure and / or the second catching part is provided with a second concave structure. When the second thread trimmer drives the bottom thread to enter the position between the first catching part and the second catching part, the bottom thread is located in the range of the first concave structure and / or the second concave structure.

Description

Technical Field

[0001] This utility model relates to the field of sewing equipment technology, specifically to a thread-cutting mechanism that can reduce bird nest problems, and a sewing machine. Background Technology

[0002] If the position of the bobbin thread end is not controlled after the flatbed sewing machine cuts the thread, it may droop in any direction, causing several stitches to fail to form a stitch when starting the sewing. This is commonly known as "the bobbin thread not being picked up during the start-up," or "the thread not being picked up during the start-up," thus affecting the sewing work. A utility model patent with application number CN202220259051.6 provides a thread-cutting mechanism that employs a bobbin thread capture technology. This involves setting up a bobbin thread capture component with an arc-shaped capture plate. The first capture part on the first thread cutter and the first capture part on the outer arc surface of the arc-shaped capture plate work together to stabilize the position of the bobbin thread end after cutting, achieving bobbin thread capture. However, this design has certain problems: when capturing the bobbin thread, especially when the captured bobbin thread is thick, the capture tension (the clamping constraint force of the first capture part and the first capture part) is too high, causing more bobbin thread to be pulled out from the bobbin. This results in a longer thread end remaining on the fabric after sewing, forming a bird's nest, which increases the size of the bird's nest during the start-up and affects the aesthetics of the stitch. Utility Model Content

[0003] In view of the shortcomings of the prior art described above, the technical problem to be solved by this utility model is to provide a thread-cutting mechanism and a sewing machine that can reduce the bird nest problem, thereby reducing the binding force on the thread while ensuring the capture of the bottom thread, and reducing the bird nest problem.

[0004] To achieve the above objectives, this utility model provides a thread-cutting mechanism that can reduce bird nest problems. This mechanism is used to cut thread at the rotary hook of a sewing machine. The thread-cutting mechanism includes a first thread-cutting blade, a second thread-cutting blade, and a thread catcher. The first thread-cutting blade is fixedly installed on the outer periphery of the rotary hook. The second thread-cutting blade is located on the outer periphery of the rotary hook and can rotate around the rotary hook to engage or disengage with the second thread-cutting blade. The second thread-cutting blade has a thread-cutting hook for driving the thread towards the first thread-cutting blade. The thread catcher includes an arc-shaped catching plate arranged along the outer periphery of the rotary hook, and the arc-shaped catching plate is located at... Between the rotary hook and the first thread cutter, the first thread cutter has a first capturing part on its side facing the rotary hook, and the outer arc surface of the arc-shaped capturing plate has a second capturing part that cooperates with the first capturing part; when cutting the thread, the second thread cutter rotates toward the first thread cutter and causes the thread hook to drive the thread thread into the space between the first capturing part and the second capturing part. The first capturing part has a first recessed structure and / or the second capturing part has a second recessed structure. When the second thread cutter drives the thread thread into the space between the first capturing part and the second capturing part, the thread thread is located within the range of the first recessed structure and / or the second recessed structure.

[0005] Furthermore, the second capturing part is provided with a second recessed structure, while the first capturing part is not provided with a first recessed structure.

[0006] Furthermore, the second recessed structure is a groove structure that does not penetrate the arc-shaped capture piece.

[0007] Furthermore, the second recessed structure penetrates the arc-shaped capture piece to form a through-hole structure.

[0008] Furthermore, the arc length L of the second recessed structure in the circumferential direction of the outer arc surface of the arc-shaped capture piece is 2 to 10 mm.

[0009] Furthermore, the arc-shaped capturing piece has one end facing the second wire cutter as side A and the other end as side B. The right side of the arc-shaped capturing piece has a guide side portion, which gradually extends to the right from side A to side B. The second recessed structure extends to the guide side portion.

[0010] Furthermore, the first recessed structure and the second recessed structure are located within the left and right range of the wire-cutting hook of the second wire cutter.

[0011] Furthermore, the arc-shaped capturing plate has one end facing the second wire cutter as side A and the other end as side B. The arc-shaped capturing plate has a guide slope extending from its right side to side B to the outer arc surface of the arc-shaped capturing plate, and the guide slope is a smooth transition surface. The second wire cutter has a wire-separating tip for inserting into the thread loops to separate the threads. The wire-separating tip is located to the right of the wire-cutting hook. When the second wire cutter moves toward the first wire cutter, the wire-separating tip is opposite to the guide slope.

[0012] This utility model also provides a sewing machine, including a rotary hook and the aforementioned thread-cutting mechanism, wherein the thread-cutting mechanism is disposed at the rotary hook to cut the thread.

[0013] As described above, the thread-cutting mechanism and sewing machine involved in this utility model have the following beneficial effects:

[0014] By providing a second recessed structure on the second capturing part and / or a first recessed structure on the first capturing part, the first capturing part and the second capturing part capture the bottom thread end during thread cutting, stabilizing the position of the bottom thread end. The bottom thread end is simultaneously located within the range of the first recessed structure and / or the second recessed structure. The first recessed structure and / or the second recessed structure can reduce the contact area between the first capturing part and / or the second capturing part and the bottom thread, thereby reducing some of the clamping constraint force on the bottom thread end. This ensures that the bottom thread end is stabilized between the first capturing part and the second capturing part, and also prevents the bottom thread end from being clamped too tightly, causing more bottom thread to be pulled out from the bobbin, thereby reducing stitch nests and improving the aesthetics of the stitches. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the wire-cutting mechanism of this utility model.

[0016] Figure 2 for Figure 1 An exploded view of the wire-cutting mechanism structure.

[0017] Figure 3 This is a schematic diagram of a certain embodiment of the baseline capture component in this utility model.

[0018] Figure 4 This is a schematic diagram of the structure of the second wire cutter in this utility model.

[0019] Figure 5 This is a schematic diagram of the structure of the first wire cutter in this utility model.

[0020] Figure 6 This is a schematic diagram showing the operation of the second wire cutter when it approaches the first wire cutter in this utility model.

[0021] Figure 7 This is a schematic diagram of the wire-cutting mechanism of this utility model capturing the bottom line after wire cutting.

[0022] Figure 8 This is a schematic diagram of the wire-cutting mechanism of this utility model capturing the bottom line after wire cutting.

[0023] Explanation of icon numbers

[0024] 1 First Thread Cutter

[0025] 101 First Capture Division

[0026] 2. Second wire cutter

[0027] 201 Wire Cutting Hook

[0028] 202 Points Tip

[0029] 3 Bottom-line capture components

[0030] 301 Installation Department

[0031] 302 Arc-shaped Snap-in Plate

[0032] 303 Second Capture Division

[0033] 304 Second Depression Structure

[0034] 305 Guide side

[0035] 306 Guide slope

[0036] 4. Bottom Line

[0037] 5. Rotary shuttle

[0038] 6 needles Detailed Implementation

[0039] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.

[0040] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of this invention, should still fall within the scope of the technical content disclosed herein. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0041] See Figures 1 to 8 This utility model provides a thread-cutting mechanism that can reduce bird nest problems. It is used to cut thread at the rotary hook 5 of a sewing machine. The thread-cutting mechanism includes a first thread cutter 1, a second thread cutter 2, and a thread catcher 3. The first thread cutter 1 is fixedly installed on the outer periphery of the rotary hook 5. The second thread cutter 2 is located on the outer periphery of the rotary hook 5 and can rotate around the rotary hook 5 to engage or disengage with the thread cutter 2. The second thread cutter 2 is provided with a thread-cutting hook 201 for driving the thread 4 towards the first thread cutter 1. The thread catcher 3 includes components arranged along the outer periphery of the rotary hook 5. An arc-shaped capturing plate 302 is located between the rotary hook 5 and the first thread cutter 1. The thread catcher 3 is fixedly mounted on the sewing machine at a suitable position via a mounting part 301. The first thread cutter 1 has a first capturing part 101 on its side facing the rotary hook 5. The outer arc surface of the arc-shaped capturing plate 302 has a second capturing part 303 that cooperates with the first capturing part 101. When cutting the thread, the second thread cutter 2 rotates towards the first thread cutter 1, causing the thread hook 201 to pull the thread 4 into the space between the first capturing part 101 and the second capturing part 303. The first thread cutter 1, the second thread cutter 2, and the thread catcher 3 can all adopt existing designs. In this invention, the first capturing part 101 has a first recessed structure and / or the second capturing part 303 has a second recessed structure 304. When the second thread cutter 2 pulls the thread 4 into the space between the first capturing part 101 and the second capturing part 303, the thread 4 is located within the range of the first recessed structure and / or the second recessed structure 304.

[0042] The main working principle of the thread cutting mechanism involved in this utility model is as follows: During normal operation, the second thread cutting blade 2 remains stationary, away from the first thread cutting blade 1. At this time, the second capturing part 303 on the arc-shaped capturing plate 302 and the first capturing part 101 on the first thread cutting blade 1 are opposite to and close to each other. They may or may not be in contact. The first capturing part 101 and the second capturing part 303 each have a certain area, and the rotary hook 5 can rotate normally. When cutting the thread, the second thread cutting blade 2 rotates towards the first thread cutting blade 1. The second thread cutting blade 2 can first contact the first thread cutting blade 1 and lift it up. Under certain size conditions, it can also press on the arc-shaped capturing plate 302 to deform it downwards. The first capturing part 101 and the second capturing part 303 separate, and the thread cutting hook 201 will drive the bottom thread 4 and the top thread to extend between the first capturing part 101 and the second capturing part 303. Then, the second thread cutting blade 2 and the first thread cutting blade 1 engage, and the thread cutting action is completed below the needle 6. After the thread is cut, the second thread cutter 2 rotates and resets, moving away from the first thread cutter 1. The first capturing part 101 and the second capturing part 303 approach and capture the end of the bottom thread 4. (See below) Figure 7 and Figure 8 The position of the bottom thread 4 is stabilized, and the bottom thread 4 is located within the range of the first recessed structure and / or the second recessed structure 304. By setting the first recessed structure and / or the second recessed structure 304, the contact area between the first capturing part 101 and / or the second capturing part 303 and the bottom thread 4 can be reduced, thereby reducing some of the clamping constraint force on the bottom thread 4. This ensures that the bottom thread 4 is stabilized between the first capturing part 101 and the second capturing part 303, and also prevents the bottom thread 4 from being clamped too tightly, causing more bottom thread 4 to be pulled out from the bobbin, thereby reducing stitch nests and improving the aesthetics of the stitch.

[0043] The wire-cutting mechanism of this utility model will be further described below with reference to several specific embodiments:

[0044] Example 1:

[0045] See Figure 3 and Figure 5 In this embodiment, as a preferred design, the second capturing part 303 is provided with a second recessed structure 304, while the first capturing part 101 is not provided with a first recessed structure. This results in better capturing effect on the baseline 4 and a simpler structure. The second recessed structure 304 is a groove structure that does not penetrate the arc-shaped capturing piece 302. The bottom surface of the groove is arc-shaped in the width direction. This groove structure can reduce the capturing constraint force on the baseline 4 while ensuring the structural strength of the arc-shaped capturing piece 302.

[0046] In this embodiment, see Figure 3 and Figure 6As a preferred design, the second recessed structure 304 extends a certain length circumferentially on the outer arc surface of the arc-shaped capture piece 302, and the arc length L is 2-10mm. The projection of the extension direction of the second recessed structure 304 onto the horizontal plane can be along the front-to-back direction, or it can be slightly tilted to the left or right at a certain angle. After the thread is cut, the thread end of the bobbin 4 can be well located in the second recessed structure 304. At the same time, the second recessed structure 304 has a certain width in the left-right direction of the sewing machine (that is, in the axial direction of the arc-shaped capture piece 302), and the second recessed structure 304 is located within the left and right range of the thread cutting hook 201 on the second thread cutter 2. That is, the left side of the second recessed structure 304 does not exceed the leftmost side of the thread cutting hook 201, and the right side of the second recessed structure 304 does not exceed the rightmost side of the thread cutting hook 201, so as to better ensure that the bobbin 4 is located in the second recessed structure 304 during thread cutting.

[0047] In this embodiment, see Figure 3 As a preferred design, the curved capture piece 302 has one end facing the second thread cutter 2 as side A and the other end as side B. The axis of the rotary hook 5 is along the left-right direction of the sewing machine, and the rotary hook 5 is located on the left side of the sewing machine. The first thread cutter 1 and the second thread cutter 2 are located on the front and rear sides of the sewing machine, respectively. When the bobbin thread catcher 3 is installed, the A-side of the curved capture piece 302 faces the rear side of the sewing machine, and the B-side of the curved capture piece 302 faces the front side and is connected to the mounting part 301. The right side of the curved capture piece 302 has a guide side portion 305, which gradually extends to the right from side A to side B. That is, from a top view, the guide side portion 305 is inclined from the left rear to the right front, and its shape can be either a straight line or a curve. The rear end of the second recessed structure 304 extends to the guide side portion 305. During wire cutting, the bottom line 4 and the top line move along the guide side 305 on the right side of the arc-shaped capturing piece 302 and are guided into the range of the second recessed structure 304, thereby better ensuring that the bottom line 4 can be smoothly located within the range of the second recessed structure 304 after wire cutting. In other embodiments, the installation directions of the first wire cutting blade 1 and the second wire cutting blade 2 can also be reversed, that is, the A side end of the wire separating piece 302 faces forward and the B side end faces backward.

[0048] In this embodiment, see Figure 3As a preferred design, the arc-shaped capture plate 302 has a guide slope 306 extending from its right side to the B side end to the outer arc surface of the arc-shaped capture plate 302, and the guide slope 306 is a smooth transition surface. The second wire cutter 2 has a wire separating tip 202 for inserting into the wire loops to separate the wires. The wire separating tip 202 is located to the right of the wire cutting hook 201. When the second wire cutter 2 moves toward the first wire cutter 1, the wire separating tip 202 is opposite to the guide slope 306. Because the curved capture plate 302 and the second thread cutter 2 may vibrate slightly during the operation of the sewing machine, the guide slope 306 makes the thickness of the right side of the curved capture plate 302, which is opposite to the thread-separating tip 202, thinner. When the second thread cutter 2 moves toward the first thread cutter 1, even if there is slight vibration, the thread-cutting hook 201 can still smoothly enter the outer arc surface of the curved capture plate 302 through the guide slope 306, thereby reducing the risk of the second thread cutter colliding with the curved capture plate 302 and ensuring that the first thread cutter 1 and the second thread cutter 2 can cut the thread smoothly.

[0049] Example 2:

[0050] In this embodiment, a first recessed structure is provided on the first capturing part 101, while the second capturing part 303 does not have a second recessed structure 304. The first recessed structure is also a groove structure that does not penetrate the first wire cutter 1. Its arc length and width can be the same as the arc length and width of the second recessed structure 304 in the first embodiment described above, and the shapes and positions of the two remain relative. The first recessed structure can also be a through-hole structure that penetrates the first wire cutter 1.

[0051] Example 3:

[0052] A first recessed structure is provided on the first capturing part 101, and a second recessed structure 304 is provided on the second capturing part 303. At this time, the first recessed structure and the second recessed structure 304 can be preferably set as groove structures or through hole structures.

[0053] This utility model also provides a sewing machine, including a rotary hook 5 and the aforementioned thread-cutting mechanism, which is disposed at the rotary hook 5 to cut the thread.

[0054] As can be seen from the above, the thread-cutting mechanism and sewing machine of this utility model have the following beneficial effects:

[0055] By providing a second recessed structure 304 on the second capturing part 303 and / or a first recessed structure on the first capturing part 101, the first capturing part 101 and the second capturing part 303 capture the end of the bobbin thread 4 during thread cutting, stabilizing the position of the end of the bobbin thread 4. The end of the bobbin thread 4 is simultaneously located within the range of the first recessed structure and / or the second recessed structure 304. The first recessed structure and / or the second recessed structure 304 can reduce the contact area between the first capturing part 101 and / or the second capturing part 303 and the bobbin thread 4, thereby reducing some of the clamping constraint force on the end of the bobbin thread 4. This ensures that the end of the bobbin thread 4 is stabilized between the first capturing part 101 and the second capturing part 303, and also prevents the end of the bobbin thread 4 from being too tightly clamped, causing more bobbin thread 4 to be pulled out from the bobbin, thereby reducing stitch nests and improving the aesthetics of the stitches.

[0056] In summary, this utility model effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0057] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A thread-cutting mechanism for reducing bird nest problems, used to cut thread at the rotary hook (5) of a sewing machine, the thread-cutting mechanism comprising a first thread-cutting blade (1), a second thread-cutting blade (2), and a thread catcher (3), the first thread-cutting blade (1) being fixedly mounted on the outer periphery of the rotary hook (5), the second thread-cutting blade (2) being disposed on the outer periphery of the rotary hook (5) and capable of rotating around the rotary hook (5) to engage or disengage with the second thread-cutting blade (2), the second thread-cutting blade (2) being provided with a thread-cutting hook (201) for driving the thread (4) toward the first thread-cutting blade (1), the thread catcher (3) comprising a thread-cutting hook (201) along the… An arc-shaped capturing plate (302) is arranged on the outer periphery of the rotary hook (5), and the arc-shaped capturing plate (302) is located between the rotary hook (5) and the first thread cutter (1). The first thread cutter (1) has a first capturing part (101) on its side facing the rotary hook (5). The outer arc surface of the arc-shaped capturing plate (302) has a second capturing part (303) that cooperates with the first capturing part (101). When cutting the thread, the second thread cutter (2) rotates toward the first thread cutter (1) and causes the thread cutting hook (201) to drive the thread (4) to extend between the first capturing part (101) and the second capturing part (303). The characteristic is that: The first capturing part (101) is provided with a first recessed structure and / or the second capturing part (303) is provided with a second recessed structure (304). When the second wire cutter (2) drives the bottom thread (4) into the space between the first capturing part (101) and the second capturing part (303), the bottom thread (4) is located within the range of the first recessed structure and / or the second recessed structure (304).

2. The wire-cutting mechanism according to claim 1, characterized in that: The second capturing part (303) is provided with a second recessed structure (304), while the first capturing part (101) is not provided with a first recessed structure.

3. The wire-cutting mechanism according to claim 1 or 2, characterized in that: The second recessed structure (304) is a groove structure that does not penetrate the arc-shaped capture piece (302).

4. The wire-cutting mechanism according to claim 1 or 2, characterized in that: The second recessed structure (304) penetrates the arc-shaped capture piece (302) to form a through-hole structure.

5. The wire-cutting mechanism according to claim 1 or 2, characterized in that: The second recessed structure (304) has an arc length L of 2 to 10 mm in the circumferential direction on the outer arc surface of the arc-shaped capture piece (302).

6. The wire-cutting mechanism according to claim 1 or 2, characterized in that: The arc-shaped capture piece (302) has one end facing the second wire cutter (2) as side A and the other end as side B. The right side of the arc-shaped capture piece (302) has a guide side portion (305). The guide side portion (305) gradually extends to the right from side A to side B. The second recessed structure (304) extends to the guide side portion (305).

7. The wire-cutting mechanism according to claim 1, characterized in that: The first recessed structure and the second recessed structure (304) are located within the left and right range of the wire cutting hook (201) of the second wire cutter (2).

8. The wire-cutting mechanism according to claim 1, characterized in that: The arc-shaped capture plate (302) has one end facing the second wire cutter (2) as side A and the other end as side B. The arc-shaped capture plate (302) has a guide slope (306) extending from its right side to the B side to the outer arc surface of the arc-shaped capture plate (302), and the guide slope (306) is a smooth transition surface. The second wire cutter (2) has a dividing tip (202) for inserting into the thread loops to divide the thread. The dividing tip (202) is located to the right of the wire cutter hook (201). When the second wire cutter (2) moves toward the first wire cutter (1), the dividing tip (202) is opposite to the guide slope (306).

9. A sewing machine, comprising a rotary hook (5), characterized in that: It also includes a wire-cutting mechanism as described in any one of claims 1 to 8, wherein the wire-cutting mechanism is disposed at the rotary hook (5) to cut the wire.

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