CN220224570U - Thread cutting mechanism capable of stabilizing length of thread end of upper thread and sewing machine - Google Patents

Abstract

The utility model relates to a thread cutting mechanism capable of stabilizing the length of an upper thread end and a sewing machine, which are used for cutting threads at a rotating shuttle of the sewing machine.

Description

Thread cutting mechanism capable of stabilizing length of thread end of upper thread and sewing machine

Technical Field

The utility model relates to the technical field of sewing, in particular to a thread cutting mechanism capable of stabilizing the length of a thread end of an upper thread and a sewing machine.

Background

A sewing machine is a machine that uses one or more sewing threads to form one or more stitches on a fabric, and interweaves or sews one or more layers of the fabric. The sewing machine is generally composed of a feeding device, a base, a transmission part and an accessory part, and the sewing materials are sewn together through reasonable matching and circulating work of the movements of the mechanisms.

At present, in the existing thread cutting mechanism, the upper thread loop is separated and enlarged by the thread separating part arranged on the movable knife in the thread cutting process, referring to fig. 1 and 2, the thread separating tip 52 is arranged on the second thread cutting knife 5 (movable knife), the right side of the thread separating tip 52 is provided with a thread separating side 521 extending rightward, the thread separating tip 52 is inserted into the upper thread 3 loop to separate the upper thread loop when the thread is cut, the upper thread loop comprises three parts of a needle edge 32, a cloth edge 31 and a connecting line 33 between the needle edge 32 and the cloth edge 31, the needle edge 32 moves rightward along the thread separating side 521, the needle edge 32 and the cloth edge 31 are separated, thus the cloth edge 31 can be conveniently cut when the thread is cut, and a certain length of upper thread head (35-45 mm) can be left below the needle 7 after the upper thread loop is enlarged.

In the seam starting and sewing process after thread cutting, the control system controls the electronic thread clamp to bring the residual upper thread into the front needles on the back of the seam material to repeatedly wind so as to form a round bird nest. On the one hand, due to factors such as unstable response delay in the control time sequence and the electronic thread clamping process, the upper thread clamping can still be kept in the thread taking-up process of the thread take-up lever, so that the thread end of the rotating shuttle expanding thread loop below the seam material can not be retracted, and the round bird nest at the seam material seam lifting position is further enlarged. On the other hand, current movable knife enlarges the wire loop process at the separated time, and the suture can slide on the separated time side, and although can be with upper thread wire loop separately, conveniently cut the line, but can directly influence the back upper thread end of a thread length of cutting the line, makes its obvious length, and because the upper thread wire loop can also slide on the right side on the separated time point portion along the suture when cutting the line, upper thread end of a thread length is also unstable. The longer and thicker the thread end residue of the shear thread is, the smaller the needle pitch is, and the bigger the bird nest is, which can affect the quality of the sewed product.

Disclosure of Invention

In view of the above-described drawbacks of the prior art, an object of the present utility model is to provide a thread cutting mechanism capable of stabilizing a length of a head of an upper thread, and a sewing machine capable of stabilizing and reducing the length of the head of the upper thread while ensuring separation of the loops of the upper thread when cutting the thread.

In order to achieve the above purpose, the utility model provides a thread cutting mechanism capable of stabilizing the length of an upper thread end, which is used for cutting threads at a rotating shuttle of a sewing machine, and comprises a first thread cutting knife and a second thread cutting knife, wherein a first cutting edge is arranged on the first thread cutting knife, a second cutting edge and a branching tip part used for being inserted into an upper thread loop are arranged on the second thread cutting knife, a branching side edge is arranged on the right side edge of the branching tip part, the second thread cutting knife can rotate relative to the first thread cutting knife until the second cutting edge is meshed with or separated from the first cutting edge, a V-shaped positioning notch is arranged on the right side edge of the branching tip part and is positioned on the right end side of the branching side edge, and the left side edge of the V-shaped positioning notch is connected with the branching side edge.

Further, when the first thread cutter and the second thread cutter are meshed in a thread cutting state, the distance between the bottom of the groove of the V-shaped positioning notch and the axis of the needle of the sewing machine in the left-right direction and the distance between the bottom of the groove and the axis of the needle of the sewing machine in the front-back direction are respectively X and Y, X is 6.5-8 mm, and Y is 10-12 mm.

Further, when the first thread cutter and the second thread cutter are meshed in a thread cutting state, an included angle theta between a plane formed by the bottom of the groove of the V-shaped positioning notch and the needle axis of the sewing machine and a plane passing through the needle axis and vertical to the left-right direction is 33-41 degrees.

Further, the second thread cutting knife is arc-shaped and coaxially arranged at the outer peripheral side of the rotating shuttle, and the second cutting edge is positioned on the extrados of the second thread cutting knife.

Further, a protruding bulge is arranged on the outer cambered surface of the second thread cutter, a through hole is formed in the bulge, the edge of the through hole forms a second cutting edge, and the through hole is coaxial with a needle of the sewing machine when the second thread cutter is meshed with the first thread cutter in a thread cutting state.

Further, the second wire cutting knife is provided with a wire cutting hook, and the outer cambered surface of the second wire cutting knife is also provided with a wire containing groove for connecting the through hole and the wire cutting hook.

Further, the first wire cutter is fixed, and the second wire cutter can rotate around the rotating shuttle to be engaged with or separated from the first wire cutter.

The utility model also provides a sewing machine which comprises a rotating shuttle and the thread cutting mechanism, wherein the thread cutting mechanism is arranged at the rotating shuttle to cut threads.

As described above, the thread cutting mechanism and the sewing machine according to the present utility model have the following advantageous effects:

the right side edge of the branching tip of the second thread cutting knife is provided with the V-shaped positioning notch, when a thread is cut, the selvedge thread enters the V-shaped positioning notch along the branching side edge, and the position of the needle edge is limited through the bottom of the V-shaped positioning notch; on the other hand, compare in current design, can reduce the length of upper thread wire loop when interlock cut the line, and length can remain stable controllable, and the upper thread end length that forms after cutting the line is accomplished is shorter, reduces the bird's nest that forms when playing the seam, guarantees the quality of seam goods.

Drawings

Fig. 1 is a schematic structural view of a prior art thread cutting mechanism.

Fig. 2 is a schematic structural view of a second wire cutter in the wire cutting mechanism of the prior art.

Fig. 3 is a schematic structural view of a second wire cutter in the wire cutting mechanism of the present utility model.

Fig. 4 is a schematic structural view of the thread cutting mechanism of the present utility model.

Description of the reference numerals

1. Bottom plate

2. Needle bar

3. Facial line

31. Edge line

32. Needle edge

33. Connecting wire

4. First thread trimmer

41. A first cutting edge

5. Second thread trimmer

51. Second cutting edge

52. Branching tip

521. Branching side edge

53 V-shaped positioning notch

531. Groove bottom

54. Thread cutting hook

55. Rong Xiancao

56. Bulge and bulge

57. Through hole

6. Bottom line

7. Machine needle

8. Branching sheet

Detailed Description

Further advantages and effects of the present utility model will become apparent to those skilled in the art from the disclosure of the present utility model, which is described by the following specific examples.

It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the utility model to the extent that it can be practiced, since modifications, changes in the proportions, or adjustments of the sizes, which are otherwise, used in the practice of the utility model, are included in the spirit and scope of the utility model which is otherwise, without departing from the spirit or scope thereof. Also, the terms such as "upper", "lower", "left", "right", "middle", etc. are used herein for convenience of description, but are not to be construed as limiting the scope of the utility model, and the relative changes or modifications are not to be construed as essential to the scope of the utility model.

Referring to fig. 3 and 4, the present utility model provides a thread cutting mechanism capable of stabilizing the length of a thread end of an upper thread, which is used for cutting threads at a rotating shuttle of a sewing machine, and is positioned below a base plate 1, wherein in the sewing machine, the rotating shuttle is positioned at the left side of the sewing machine along the left-right direction of the axis of the rotating shuttle, and the rotating shuttle is positioned at the lower side of a needle 7. The thread cutting mechanism comprises a first thread cutting knife 4 and a second thread cutting knife 5, wherein the first thread cutting knife 4 is provided with a first cutting edge 41, the second thread cutting knife 5 is provided with a second cutting edge 51 and a thread separating tip 52 for being inserted into an upper thread loop, the right side edge of the thread separating tip 52 is provided with a thread separating side 521, the second thread cutting knife 5 is also provided with a thread cutting hook 54 for hooking the bottom thread 6 and the cloth thread 32 in the upper thread 3 to move towards the first thread cutting knife 4, the thread cutting hook 54 and the thread separating tip 52 share one side, and the second thread cutting knife 5 can rotate relative to the first thread cutting knife 4 until the second cutting edge 51 is meshed with or separated from the first cutting edge 41. In the present utility model, the right side of the branching tip 52 is further provided with a V-shaped positioning notch 53 located at the right end of the branching side 521, and the left side of the V-shaped positioning notch 53 is engaged with the branching side 521, so that the selvedge thread 31 can smoothly enter the V-shaped positioning notch 53 from the branching side 521.

The basic working principle of the thread cutting mechanism related by the utility model is as follows: referring to fig. 3 and 4, when the second thread cutter 5 rotates toward the first thread cutter 4, the second thread cutter 5 rotates, the thread splitting tip 52 enters the upper thread loop, the needle thread 32 moves rightward along the thread splitting side 521 and enters the V-shaped positioning notch 53, and reaches the bottom 531 of the V-shaped positioning notch 53, and is limited to the bottom 531 and does not move any more, the selvedge 31 enters the thread cutting hook 54, the thread cutting hook 54 hooks the bottom 6 and the selvedge 31, and drives the bottom 6 and the selvedge 31 to approach the first thread cutter 4, and then engages the first thread cutter 4 to cut the thread. When the needle edge 32 is engaged with the thread, the length of the loop of the thread can be kept stable when the thread is engaged with the thread, as shown in fig. 4, because the needle edge 32 is positioned at the limited column position in the bottom 531 of the V-shaped positioning notch 53, and the needle edge 32 and the cloth edge 31 are separated with a certain distance therebetween, and the cutting of the needle edge 32 can be avoided when the first cutting edge 41 and the second cutting edge 51 cut the cloth edge 31. Meanwhile, compared with the existing design, the length of the upper thread loop is shorter, the length can be kept stable and controllable, the length of the formed upper thread end is shorter after thread trimming is completed, the bird nest formed during seam starting is reduced, and the quality of a seam product is guaranteed.

Referring to fig. 3 and 4, the present utility model is further illustrated in one embodiment as follows:

in this embodiment, referring to fig. 3 and 4, the position and depth of the V-shaped positioning notch 53 may be set according to the requirement in actual thread trimming, and as a preferred design, when the first thread trimming blade 4 and the second thread trimming blade 5 are engaged in the thread trimming state, the distance between the bottom 531 of the V-shaped positioning notch 53 and the needle 7 of the sewing machine in the left-right direction and the distance between the bottom 531 and the front-rear direction are X and Y, respectively, X is 6.5-8 mm, Y is 10-12 mm, and by setting appropriate values of X and Y, the length of the wire loop in the thread trimming can be controlled. Preferably, when the first thread cutter 4 and the second thread cutter 5 are engaged in a thread cutting state, an included angle θ between a plane formed by the bottom 531 of the V-shaped positioning notch 53 and the axis of the needle 7 of the sewing machine and a plane passing through the axis of the needle 7 and vertical to the left-right direction is 33-41 °, wherein the magnitude of θ can be determined by setting the magnitude of the ratio of X to Y, and specifically, X/Y is 0.54-0.8. The included angle θ can determine the distance between the needle edge 32 and the cloth edge 31 when the needle edge 32 is engaged with the cutting line, so that the distance is in a proper range, the needle edge 32 is beneficial to avoiding the first cutting edge 41 and the second cutting edge 51, and the needle edge 32 is prevented from being cut.

In this embodiment, referring to fig. 3 and 4, as a preferred design, the second thread cutter 5 is in a circular arc shape, and is coaxially disposed at the outer peripheral side of the rotating shuttle, keeping a certain distance, the second thread cutter 5 does not touch the rotating shuttle when working, the second cutting edge 51 is located on the outer arc surface of the second thread cutter 5, and the hour hand edge 32 is located on the outer arc surface. The first thread cutting knife 4 is a fixed knife, is fixed and is close to the front side, the needle 7 is located at the lower end of the needle rod 2, the first cutting edge 41 is located at the needle 7 and near the lower portion of a needle plate hole of a needle plate, the second thread cutting knife 5 is a movable knife, the first thread cutting knife 4 is located at the rear side of the second thread cutting knife 5, and the second thread cutting knife 5 is driven by a corresponding driving mechanism and can rotate backwards around the rotating shuttle to be meshed with or separated from the first thread cutting knife 4. Of course, in other embodiments, the second wire cutter 5 may be on the rear side and the first wire cutter 4 on the front side when no wire is cut. The first wire cutter 4 may be a movable cutter and may be rotatable toward the second wire cutter 5.

In this embodiment, referring to fig. 3 and 4, as a preferred design, the protruding bulge 56 is provided on the outer arc surface of the second thread cutter 5, the through hole 57 is provided on the bulge 56, the edge of the through hole 57 forms the second cutting edge 51, when the thread is cut, the outer arc surface of the second thread cutter 5 is inserted into the lower side surface (i.e. the side surface facing the rotating shuttle) of the first thread cutter 4, the second cutting edge 51 on the bulge 56 contacts and engages with the first cutting edge 41, the selvedge thread 31 and the bottom thread 6 can be cut off stably, and at this time, the through hole 57 is coaxial with the needle 7 of the sewing machine, and can be used for the needle 7 to pass. In this way, when the V-shaped positioning notch 53 is machined on the second wire cutter 5, the V-shaped positioning notch 53 is determined by the distance X, the distance Y and the included angle θ, and at this time, the reference point can be selected from the axial center of the through hole 57, so that machining and positioning are facilitated.

In this embodiment, referring to fig. 3 and 4, the outer arc surface of the second wire cutter 5 is further provided with a wire accommodating groove 55 for connecting the through hole 57 and the wire cutting hook 54, and when the wire is cut by biting, the selvedge wire 31 and the bottom wire 6 are positioned in the wire accommodating groove 55, thereby stabilizing the positions of the selvedge wire 31 and the bottom wire 6.

In this embodiment, referring to fig. 3 and 4, the thread cutting mechanism further includes a thread separating sheet 8, where the thread separating sheet 8 is also in an arc structure and is disposed below the second thread cutting blade 5, that is, on the side surface of the second thread cutting blade 5 near the rotating shuttle, and when cutting threads, the second thread cutting blade 5 is inserted above the thread separating sheet 8, and the thread separating sheet 8 is used to separate the upper thread loop better.

The utility model also provides a sewing machine, which comprises the rotating shuttle and the thread cutting mechanism, wherein the thread cutting mechanism is arranged at the rotating shuttle to cut threads.

The thread cutting mechanism and the sewing machine have the following beneficial effects:

1. through set up V type location notch 53 on the separated time point portion 52 right side of second thread trimmer 5, will restrict needle limit line 32 position through the tank bottom 531 of V type location notch 53 when cutting the line, on the one hand for interlock is cut the needle limit line 32 and is separated certain distance with cloth limit line 31, thereby avoid first blade 41 and second blade 51 to contact with needle limit line 32, avoid cutting needle limit line 32, on the other hand, compare in current design, can reduce the length of upper thread line loop when interlock cuts the line, and length can keep stable controllable, the upper thread end length that forms after the cut line is accomplished is shorter, reduce the bird's nest that forms when playing the seam, guarantee the quality of sewing goods.

2. By setting the position of the groove bottom 531 of the V-shaped positioning notch 53, the length of the upper thread loop when the upper thread is snapped and sheared is conveniently controlled.

3. Simple structure can be improved on current thread cutting mechanism, and the cost is with low costs.

In summary, the present utility model effectively overcomes the disadvantages of the prior art and has high industrial utility value.

The above embodiments are merely illustrative of the principles of the present utility model and its effectiveness, and are not intended to limit the utility model. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the utility model. Accordingly, it is intended that all equivalent modifications and variations of the utility model be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (8)

1. Can stabilize line cutting mechanism of upper thread end length for set up and cut the line in sewing machine's rotating shuttle department, including first cutting sword (4) and second cutting sword (5), be equipped with first blade (41) on first cutting sword (4), be equipped with second blade (51) on second cutting sword (5) and be used for inserting separated time point portion (52) in the upper thread wire loop, the right side of separated time point portion (52) has separated time side (521), second cutting sword (5) can rotate to second blade (51) and first blade (41) interlock or separate, its characterized in that relative first cutting sword (4): the right side of the branching tip part (52) is provided with a V-shaped positioning notch (53) positioned at the right end side of the branching side (521), and the left side of the V-shaped positioning notch (53) is connected with the branching side (521).

2. The thread cutting mechanism according to claim 1, wherein: when the first thread cutting knife (4) and the second thread cutting knife (5) are meshed in a thread cutting state, the distance between the bottom (531) of the V-shaped positioning notch (53) and the axis of the needle (7) of the sewing machine in the left-right direction and the distance between the bottom and the front-back direction are respectively X and Y, wherein X is 6.5-8 mm, and Y is 10-12 mm.

3. The thread cutting mechanism according to claim 1, wherein: when the first thread cutter (4) and the second thread cutter (5) are meshed in a thread cutting state, an included angle theta between a plane formed by the bottom (531) of the V-shaped positioning notch (53) and the axis of the needle (7) of the sewing machine and a plane which passes through the axis of the needle (7) and is vertical to the left-right direction is 33-41 degrees.

4. A wire cutting mechanism according to claim 2 or 3, wherein: the second thread cutting knife (5) is arc-shaped and coaxially arranged at the outer peripheral side of the rotating shuttle, and the second cutting edge (51) is positioned on the outer cambered surface of the second thread cutting knife (5).

5. The thread cutting mechanism as recited in claim 4, wherein: the second thread cutting knife (5) is provided with a protruding bulge (56), the bulge (56) is provided with a through hole (57), the edge of the through hole (57) forms a second cutting edge (51), and the through hole (57) and a needle (7) of the sewing machine are kept coaxial when the second thread cutting knife (5) and the first thread cutting knife (4) are meshed in a thread cutting state.

6. The thread cutting mechanism as recited in claim 5, wherein: the second wire cutting knife (5) is provided with a wire cutting hook (54), and the outer cambered surface of the second wire cutting knife (5) is also provided with a wire containing groove (55) for connecting the through hole (57) and the wire cutting hook (54).

7. The thread cutting mechanism according to claim 1 or 5, wherein: the first thread cutter (4) is fixed, and the second thread cutter (5) can rotate around the rotating shuttle to be engaged with or separated from the first thread cutter (4).

8. A sewing machine comprising a rotating shuttle, characterized in that: further comprising a thread cutting mechanism according to any one of claims 1 to 7, which is provided at the rotating shuttle to cut the thread.