Thread cutter, thread cutting mechanism and sewing machine

Abstract

The utility model provides a kind of thread cutting knife, including first thread cutting knife, first thread cutting blade is equipped on the first thread cutting knife, first thread cutting knife is equipped with first thread hooking portion for hooking bottom thread and second thread hooking portion for hooking face thread, the interval of first thread hooking portion and first thread cutting blade is less than the interval of second thread hooking portion and first thread cutting blade.The utility model further provides a kind of thread cutting mechanism and sewing machine.The utility model has the beneficial effect that by setting first thread hooking portion and second thread hooking portion from near to far on first thread cutting knife, so that thread cutting mechanism can obtain shorter bottom thread end and longer face thread end after cutting off bottom thread and cloth edge thread, avoid the problem caused by bottom thread end being too long and face thread end being too short.

Description

Technical Field

[0001] This utility model relates to the field of sewing machine technology, and in particular to a thread cutter, a thread cutting mechanism, and a sewing machine. Background Technology

[0002] When a sewing machine is working, the driving needle pulls the top thread and bottom thread to form a lockstitch on the fabric. After sewing is completed, the sewing machine drives the thread-cutting mechanism to cut the thread. The top thread on one side of the needle is connected to the fabric and is called the selvage thread; the top thread on the other side of the needle is connected to the thread feed spool and is called the needle selvage thread. When the thread-cutting mechanism cuts the thread below the needle plate, it needs to cut both the bottom thread and the selvage thread without damaging or cutting the needle selvage thread. Existing thread-cutting mechanisms have a movable blade and an auxiliary blade. The movable blade, through its hook and thread groove, hooks the bottom thread and top thread, thus separating the top thread into the needle selvage thread and the selvage thread. Then, the movable blade and the auxiliary blade engage to cut the bottom thread and the selvage thread.

[0003] Existing circular knife thread-cutting mechanisms in flat sewing machines leave both long and short thread ends after cutting the thread. Longer top thread ends can improve the stitch success rate for subsequent starts, but longer bottom thread ends can lead to more severe stitch failures. Conversely, shorter bottom thread ends offer a better stitch success rate and produce smaller "bird's nests," resulting in a neater stitch. However, shorter top thread ends, due to their insufficient length to form complete loops, reduce the stitch success rate. How to leave both short bottom thread ends and long top thread ends after thread cutting is a problem that needs to be solved by those skilled in the art. Utility Model Content

[0004] The purpose of this utility model is to provide a thread cutter that can hook the bottom thread and the fabric edge thread respectively, leaving a shorter bottom thread end and a longer top thread end after cutting.

[0005] This utility model provides a thread cutter, including a first thread cutter, a first cutting edge on the first thread cutter, a first hooking part for hooking the bottom line and a second hooking part for hooking the top line, the distance between the first hooking part and the first cutting edge is smaller than the distance between the second hooking part and the first cutting edge.

[0006] Preferably, the first thread cutter is provided with a first thread separating tip for separating the bottom line and the top line. The first thread separating tip is disposed between the first hooking part and the second hooking part, and shares a first side with the first hooking part and a second side with the second hooking part.

[0007] Preferably, the first thread cutter is further provided with a second thread-separating tip for inserting into the face thread loop. The second thread-separating tip is located on the side of the second hook portion away from the first thread-separating tip, and shares a third side with the second hook portion.

[0008] Preferably, the first wire cutter is further provided with a first wire receiving groove and a second wire receiving groove. The first wire receiving groove extends from the first wire cutting edge to the first hooking part, and the second wire receiving groove extends from the first hooking part to the second hooking part. The first wire receiving groove and the second wire receiving groove are located on the same extension path.

[0009] Preferably, the bottom surface of the first wire groove and the bottom surface of the second wire groove are arc-shaped or "U"-shaped.

[0010] Preferably, the first wire cutter has an outer arc surface, and the first wire cutting edge, the first wire receiving groove, and the second wire receiving groove are all disposed on the outer arc surface.

[0011] This utility model also provides a thread cutting mechanism, which is set at the rotary hook of a sewing machine to cut the thread. It includes the aforementioned first thread cutting knife and a second thread cutting knife. The second thread cutting knife is provided with a second thread cutting edge. The first thread cutting knife can rotate relative to the second thread cutting knife, so that the first thread cutting edge and the second thread cutting edge can engage or separate.

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

[0013] The advantage of this invention is that by setting a first hooking part and a second hooking part on the first thread cutter, which are located from the first thread cutting edge to the farthest point, the thread cutting mechanism can obtain a shorter bottom thread end and a longer top thread end after cutting the bottom thread and the selvage thread. This avoids problems caused by an excessively long bottom thread end and problems caused by an insufficient length of top thread end to form a complete loop, which leads to the stitch not being able to be sewn. Attached Figure Description

[0014] Figure 1 It is a perspective view of the first wire cutter used to cooperate with the second wire cutter, which is fixed in position; Figure 2 and Figure 3 These are schematic diagrams of the first wire cutter during the snap-fit ​​wire cutting process; Figure 4 This is a perspective view of the first wire cutter used in conjunction with the rotatable second wire cutter.

[0015] Component designation explanation: 1. Bottom line 2. Surface lines 21. Fabric edge line 22 stitches 3 First Thread Cutter 31. Wire-cutting bulge 311 First cutting edge 321 First Outline Section 322 First slot 323 First dividing line tip 331 Second hook section 332 Second Capacity Groove 333 Second dividing line tip 34 Chamfer 35-minute line hypotenuse 36. Raise part a First side b Second side c Third side Detailed Implementation

[0016] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings. These embodiments are only used to illustrate this utility model and are not intended to limit it.

[0017] In the description of this utility model, it should be noted that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0018] Figure 1 The image shown is a perspective view of a first wire cutter used in conjunction with a second wire cutter that is fixed in position. In the following description, [the following text is incomplete and likely refers to a different device or assembly]. Figure 1 The attached diagram serves as a reference for direction. Figure 1 In the above, the first wire receiving groove 322 is defined to extend from front to back, and the wire cutting bulge 31 is located on the front side of the first wire receiving groove 322; the width direction of the first wire receiving groove 322 is defined as the left-right direction, and the second side b is located to the left of the third side c; the direction that is perpendicular to both the left-right and front-back directions is defined as the up-down direction, and the wire cutting bulge 31 is located on the upper surface of the first wire cutting blade 3.

[0019] This utility model provides a wire cutter and a wire cutting mechanism equipped with the wire cutter.

[0020] like Figure 1-3As shown, the thread cutter provided by this utility model includes a first thread cutter 3, the first thread cutter 3 having a first thread cutting edge 311, and the first thread cutter 3 having a hook for hooking the bottom thread 1 ( Figure 2 The first hook section 321 of the green line in the middle and the hook section 2 for hooking the top line ( Figure 2 The distance between the second hook portion 331 (the red line in the image) and the first hook portion 321 and the first cutting edge 311 is smaller than the distance between the second hook portion 331 and the first cutting edge 311.

[0021] The wire cutting mechanism provided by this utility model includes the aforementioned first wire cutting blade 3 and second wire cutting blade. The second wire cutting blade is provided with a second wire cutting edge. The first wire cutting blade 3 can rotate relative to the second wire cutting blade, so that the first wire cutting edge 311 engages or separates from the second wire cutting edge.

[0022] The working principle of the thread-cutting mechanism provided by this utility model is as follows: When thread cutting is required, the first thread-cutting blade 3 rotates toward the second thread-cutting blade until the first thread-cutting edge 311 engages with the second thread-cutting edge. During the rotation of the first thread-cutting blade 3, the first hooking part 321 hooks the bottom thread 1, and the second hooking part 331 hooks the selvage thread 21 in the top thread 2. The two hooking parts can effectively separate the bottom thread 1 and the selvage thread 21 by a certain distance, and as the first thread-cutting blade 3 rotates, it simultaneously drives the bottom thread 1 and the selvage thread 21 closer to the second thread-cutting blade. Since the distance between the first hook part 321 and the first cutting edge 311 is smaller than the distance between the second hook part 331 and the first cutting edge 311, that is, the first hook part 321 is closer to the first cutting edge 311 than the second hook part 331, compared with the prior art, which uses the same hook part to hook the bottom thread 1 and the selvage thread 21 at the same time, the cutting mechanism provided by this utility model can obtain a shorter bottom thread end and a longer top thread end after cutting the bottom thread 1 and the selvage thread 21. This avoids the problem of the bottom thread end being too long and the problem of the top thread end being too short to form a complete loop, which leads to the stitching not being completed.

[0023] like Figure 1-3As shown, in a specific embodiment of this utility model, the first thread cutter 3 is provided with a first thread-separating tip 323 for separating the bottom thread 1 and the top thread 2, and a second thread-separating tip 333 for inserting into the top thread loop. The first thread-separating tip 323 is disposed between the first hook portion 321 and the second hook portion 331, and includes a first side a located at the front and a second side b located at the rear. The first thread-separating tip 323 shares the first side a with the first hook portion 321 and shares the second side b with the second hook portion 331. The second thread-separating tip 333 is located on the side of the second hook portion 331 away from the first thread-separating tip 323 (i.e., the right side), and includes a third side c located at the left and a thread-separating oblique edge 35 located at the right. The second thread-separating tip 333 shares the third side c with the second hook portion 331, and the thread-separating oblique edge 35 extends to the right front, causing the width of the second thread-separating tip 333 to gradually increase from back to front.

[0024] Furthermore, the first thread cutter 3 is also provided with a first thread receiving groove 322 and a second thread receiving groove 332. The first thread receiving groove 322 extends from the first thread cutting edge 311 to the first hooking part 321, and the second thread receiving groove 332 extends from the first hooking part 321 to the second hooking part 331. Both are located on the same extension path, which can be regarded as a thread receiving groove on the first thread cutter 3. This thread receiving groove is divided into front and rear sections by one end of the first hooking part 321, forming the first thread receiving groove 322 located on the front side and the second thread receiving groove 332 located on the rear side. Preferably, the bottom surface of the first thread receiving groove 322 and the bottom surface of the second thread receiving groove 332 are arc-shaped or U-shaped. The design of the bottom surface shape helps the first thread receiving groove 322 and the second thread receiving groove 332 to better accommodate the bottom thread 1 or the selvage thread 21.

[0025] During the thread cutting process of the thread cutting mechanism, the first thread separating tip 323 separates the top thread 2 from the bottom thread 1. As the first thread cutting blade 3 rotates, the bottom thread 1 enters the first hooking part 321, which hooks the bottom thread 1 and brings it to the first thread receiving groove 322. Simultaneously, the second thread separating tip 333 inserts into the top thread loop, separating the needle edge thread 22 and the fabric edge thread 21 and widening the top thread loop. As the first thread cutting blade 3 rotates, the needle edge thread 22 moves to the right along the dividing diagonal edge 35, while the fabric edge thread 21 enters the second hooking part 331 along the third side c. The second hooking part 331 hooks the fabric edge thread 21 and brings it to the second thread receiving groove 332 and the first thread receiving groove 322. During thread cutting, because the first thread receiving groove 322 has a relatively small length, the resulting bottom thread end is relatively short; while the total length of the first thread receiving groove 322 and the second thread receiving groove 332 is relatively large, resulting in a longer top thread end.

[0026] Furthermore, the first wire cutter 3 is located near the outer periphery of the rotary hook and can rotate around the rotary hook under the drive of the drive mechanism without interfering with the rotary hook during rotation. The first wire cutter 3 has an outer arc surface, and the first wire cutting edge 311, the first wire receiving groove 322, and the second wire receiving groove 332 are all located on the outer arc surface. A wire cutting bulge 31 is also provided on the outer arc surface, and a through hole is provided on the wire cutting bulge 31. The edge where the through hole intersects with the surface of the wire cutting bulge 31 forms the first wire cutting edge 311. The second wire cutting edge is located at the front end of the second wire cutter.

[0027] like Figure 1-3 As shown, when the second wire cutter is a fixed blade, the first wire cutter 3 can rotate toward the second wire cutter and insert below it, so that the first wire cutting edge 311 engages with the second wire cutting edge. Preferably, the first wire cutter 3 is also provided with a lifting part 36 inclined toward the side where the rotary hook is located, and the second wire cutter is provided with a raised part. When the first wire cutter 3 rotates toward the second wire cutter, the lifting part 36 is inserted to the lower side of the raised part, and the raised part is gradually raised, so that the first wire cutter 3 can be inserted into the lower side of the second wire cutter and the first wire cutting edge 311 engages with the second wire cutting edge to complete the wire cutting.

[0028] When the second wire cutter is a movable blade capable of rotating toward the first wire cutter, the structure of the first wire cutter 3 is as follows: Figure 4 As shown, the lifting part 36 has been removed, and there is no need to set a corresponding lifting part on the second wire cutter.

[0029] Furthermore, the second dividing tip 333 and the first wire cutter 3 located to the left of the first hook part 321 are also provided with a chamfer 34 for avoiding the second wire cutter. The chamfer 34 can prevent the first wire cutter 3 from colliding with the second wire cutter when it is inserted under the second wire cutter.

[0030] 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.

[0031] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A wire cutter, comprising a first wire cutter (3), wherein the first wire cutter (3) is provided with a first wire cutting edge (311), characterized in that, The first wire cutter (3) is provided with a first hooking part (321) for hooking the bottom line (1) and a second hooking part (331) for hooking the top line (2). The distance between the first hooking part (321) and the first wire cutting edge (311) is smaller than the distance between the second hooking part (331) and the first wire cutting edge (311).

2. The wire cutter according to claim 1, characterized in that, The first wire cutter (3) is provided with a first dividing tip (323) for separating the bottom line (1) and the top line (2). The first dividing tip (323) is located between the first hook part (321) and the second hook part (331). It shares a first side (a) with the first hook part (321) and a second side (b) with the second hook part (331).

3. The wire cutter according to claim 2, characterized in that, The first wire cutter (3) is also provided with a second wire splitting tip (333) for inserting into the face wire loop. The second wire splitting tip (333) is located on the side of the second hook part (331) away from the first wire splitting tip (323), and shares a third side (c) with the second hook part (331).

4. The wire cutter according to claim 1, characterized in that, The first wire cutter (3) is also provided with a first wire receiving groove (322) and a second wire receiving groove (332). The first wire receiving groove (322) extends from the first wire cutting edge (311) to the first hooking part (321), and the second wire receiving groove (332) extends from the first hooking part (321) to the second hooking part (331). The first wire receiving groove (322) and the second wire receiving groove (332) are located on the same extension path.

5. The wire cutter according to claim 4, characterized in that, The bottom surface of the first wire groove (322) and the bottom surface of the second wire groove (332) are arc-shaped or "U"-shaped.

6. The wire cutter according to claim 4, characterized in that, The first wire cutter (3) has an outer arc surface, and the first wire cutting edge (311), the first wire receiving groove (322), and the second wire receiving groove (332) are all disposed on the outer arc surface.

7. A thread-cutting mechanism, disposed at the rotary hook of a sewing machine for cutting thread, characterized in that, Includes a first wire cutter (3) as described in any one of claims 1-6, and a second wire cutter, wherein the second wire cutter is provided with a second wire cutting edge, and the first wire cutter (3) is rotatable relative to the second wire cutter, such that the first wire cutting edge (311) engages or separates from the second wire cutting edge.

8. A sewing machine, comprising a rotary hook, characterized in that, It also includes the thread-cutting mechanism as described in claim 7, wherein the thread-cutting mechanism is disposed at the rotary hook to cut the thread.

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