Forced reset structure for thread trimming of sewing machine

Abstract

The utility model provides a thread trimming forced reset structure of a sewing machine, and belongs to the technical field of sewing machines. The thread trimming mechanism solves the problem that a thread trimmer of an existing thread trimming mechanism is clamped after trimming and cannot reset normally. The thread trimming forced reset structure of the sewing machine comprises a thread trimming cam capable of rotating, a working convex part for a thread trimming roller to abut against is arranged on the peripheral face of the thread trimming cam, a forcing piece is fixed to the thread trimming cam, and the forcing piece comprises a forcing part which is located on the peripheral side of the thread trimming cam and corresponds to the working convex part. And an accommodating space for accommodating the thread trimming roller is formed between the forcing part and the working convex part. By means of the thread trimming forced reset structure of the sewing machine, the thread trimmer can be forced to reset when the thread trimmer is clamped after trimming and cannot reset normally, and normal use of the thread trimming mechanism is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewing machines and relates to a thread trimming forced resetting structure for sewing machines. Background Art

[0002] A sewing machine is a machine that sews sewing materials with sewing threads. Overlock sewing refers to sewing in which the sewing needle thread and the curved needle thread are connected and interconnected to hem or sew the sewing materials. An overlock sewing machine is a sewing machine that can achieve overlock sewing and is a common sewing machine. An overlock sewing machine is equipped with a thread trimming mechanism, a presser foot lifting mechanism, a tooth height adjustment mechanism, and a stitch length adjustment mechanism. With the development of automation, these mechanisms have been gradually improved and equipped with drivers, which include motors, electromagnets, cylinders, and oil cylinders.

[0003] Chinese patent literature discloses an automatic presser foot lifting, thread trimming, tooth height adjustment, and stitch length adjustment mechanism suitable for an overlock sewing machine [application number: CN202211636581.9; publication number: CN 115852595A], including a stepping motor, and a thread trimming cam is provided on the output shaft of the stepping motor. The thread trimming transmission mechanism is used to interact with the thread trimming cam and transmit motion to the thread trimmer assembly to achieve thread trimming control. The thread trimming transmission mechanism includes a first thread trimming lever, a metal ball, a second thread trimming lever, a thread trimming connecting rod, a torsion spring, and a third thread trimming lever for transmitting the thread trimming action. The thread trimmer assembly and the thread trimming transmission mechanism constitute a thread trimming mechanism.

[0004] When the thread needs to be trimmed, the stepper motor rotates to drive the trimming cam to rotate, and the trimming cam drives the trimmer to move through the trimming mechanism to trim the thread. When the stepper motor resets, the torsion spring drives the trimmer to reset. However, during use, the trimmer occasionally cannot reset after being engaged, that is, it gets stuck and cannot reset normally after trimming the thread, resulting in the inability of automatic trimming to proceed normally. Summary of the invention

[0005] The utility model aims to solve the above problems in the prior art and proposes a sewing machine thread trimmer forced reset structure to solve the technical problem that the thread trimmer of the prior art thread trimmer mechanism gets stuck and cannot be reset normally after thread trimming.

[0006] The purpose of the utility model can be achieved through the following technical solutions:

[0007] A sewing machine thread trimmer forced reset structure comprises a rotatable thread trimmer cam, wherein the outer peripheral surface of the thread trimmer cam has a working protrusion for a thread trimmer roller to abut against, and is characterized in that a forcing member is fixed to the thread trimmer cam, wherein the forcing member comprises a forcing portion located on the outer peripheral side of the thread trimmer cam and corresponding to the working protrusion, and an accommodating space for accommodating the thread trimmer roller is formed between the forcing portion and the working protrusion.

[0008] The thread trimming roller is a part of the thread trimming mechanism. When the working convex part abuts against and acts on the thread trimming roller, the thread trimming mechanism can be driven to move, thereby realizing thread trimming. When trimming the thread, the thread trimming cam rotates, the thread trimming roller enters the accommodation space, and the thread trimming roller abuts against the working convex part of the thread trimming cam and moves. After the thread trimming is completed, the thread trimming cam rotates in the opposite direction to reset. When the thread trimmer can be reset normally, under the action of the torsion spring, the thread trimming roller abuts against the working convex part and moves in the opposite direction, and moves out of the accommodation space. When the thread trimmer is stuck after trimming and cannot be reset normally, the thread trimming cam rotates while the thread trimming roller does not move. As the thread trimming cam rotates, the thread trimming roller separates from the working convex part and abuts against the forcing part. The forcing part acts on the thread trimming roller to force the thread trimming roller to move, thereby releasing the stuck state of the thread trimmer after trimming. Under the action of the torsion spring, the thread trimming roller abuts against the thread trimming cam again to realize forced reset. Therefore, the thread trimmer forced reset structure of the sewing machine can force the thread trimmer to reset when it is stuck and cannot be reset normally after thread trimming, thereby ensuring the normal use of the thread trimmer mechanism.

[0009] In the above sewing machine thread trimming forced reset structure, when the thread trimming roller abuts against the working protrusion, there is a gap between the forced part and the thread trimming roller. After such arrangement, during normal thread trimming and normal reset, the forced part does not contact the thread trimming roller, and the arrangement of the forced part does not affect normal thread trimming and reset, so that the thread trimming mechanism can be used normally.

[0010] In the above sewing machine thread trimming forced reset structure, the forcing part is in the shape of a hook bent toward the thread trimming cam. This arrangement makes the forcing part closer to the thread trimming roller, so that the forcing part can act on the thread trimming roller as quickly as possible during forced reset to achieve forced reset, so that the thread trimming mechanism can return to normal as soon as possible.

[0011] In the above sewing machine thread trimming forced reset structure, the forcing member further comprises a fixing portion fixedly connected to the thread trimming cam, and a transition portion is connected between the fixing portion and the forcing portion. The arrangement of the fixing portion and the transition portion facilitates the installation of the forcing member.

[0012] In the above-mentioned sewing machine thread trimmer forced reset structure, the fixing portion is provided with a side wing plate, and the side wing plate is abutted against the end surface of the thread trimmer cam and fixedly connected.

[0013] The side wing plate abuts against the end face of the thread trimming cam and has an axial positioning function, so that the forcing member is fixed on the thread trimming cam accurately and stably, which is conducive to ensuring the forced driving effect of the forcing member on the thread trimming roller, realizing forced resetting, and ensuring the normal use of the thread trimming mechanism.

[0014] In the above sewing machine thread trimmer forced reset structure, the side wing plate is fixedly connected to the thread trimmer cam by fixing screws. The screw fixing is convenient and detachable, which is convenient for the installation and maintenance of the forced member.

[0015] In the above sewing machine thread trimmer forced reset structure, a positioning screw is threadedly connected to one side of the working convex portion on the outer peripheral surface of the thread trimmer cam, a positioning hole corresponding to the positioning screw is opened on the fixing portion, and the positioning screw is inserted into the positioning hole.

[0016] The positioning screw is inserted into the positioning hole to form circumferential positioning for the forcing member, so that the forcing member is accurately and stably fixed on the thread trimming cam, which is beneficial to ensure the forced driving effect of the forcing member on the thread trimming roller, realize forced resetting, and ensure the normal use of the thread trimming mechanism.

[0017] Compared with the prior art, the utility model has the following advantages:

[0018] A forcing member is fixed on the thread trimming cam to forcibly reset the thread trimming roller, so that the thread trimming knife can be forcibly reset when it is stuck and cannot be reset normally after thread trimming, thereby ensuring the normal use of the thread trimming mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a three-dimensional view of a thread trimmer mechanism provided with a thread trimmer forced reset structure of the sewing machine when it is installed on a casing.

[0020] Figure 2 It is a three-dimensional diagram of the thread trimmer forced reset structure of this sewing machine.

[0021] Figure 3 This is a cross-sectional view of the thread trimming forced reset structure of the sewing machine when waiting for thread trimming.

[0022] Figure 4 This is a cross-sectional view of the thread trimming forced reset structure of the sewing machine when trimming the thread.

[0023] Figure 5 This is a cross-sectional view of the thread trimmer forced reset structure of the sewing machine when it is normally reset.

[0024] Figure 6 This is a cross-sectional view of the forced reset structure of the thread trimmer of the sewing machine when it is forced reset.

[0025] In the figure, 1, casing; 2, thread trimming crank; 3, thread trimming connecting rod; 4, thread trimming shaft; 5, thread trimming knife; 6, motor; 6a, rotating shaft; 7, thread trimming roller; 8, torsion spring; 9, thread trimming cam; 9a, working convex part; 9b, base circular surface; 10, forcing member; 10a, forcing part; 10b, transition part; 10c, fixing part; 10d, side wing plate; 10e, positioning hole; 11, positioning screw; 12, fixing screw; 13, accommodating space. DETAILED DESCRIPTION

[0026] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0027] like Figure 1 As shown, the thread trimming mechanism is installed on the casing 1 of the sewing machine, including a thread trimming crank 2, a thread trimming connecting rod 3, a thread trimming shaft 4 and a thread trimming knife 5. The thread trimming crank 2 is hinged on the rear side of the casing 1, the thread trimming shaft 4 is arranged front and back, the thread trimming knife 5 and the thread trimming connecting rod 3 are respectively fixed on the front and rear ends of the thread trimming shaft 4, the thread trimming connecting rod 3 is slidably hinged to one end of the thread trimming crank 2, a thread trimming roller 7 is arranged on the other end of the thread trimming crank 2, and a torsion spring 8 is arranged between the thread trimming crank 2 and the casing 1. A motor 6 is also fixedly connected to the casing 1 of the sewing machine, and the motor 6 is used to drive the thread trimming mechanism.

[0028] like Figure 2 and Figure 3 As shown, a sewing machine thread trimming forced reset structure includes a rotatable thread trimming cam 9, which is fixedly connected to the rotating shaft 6a of the motor 6. The outer peripheral surface of the thread trimming cam 9 is provided with a working protrusion 9a for the thread trimming roller 7 to abut against, and a forcing member 10 is fixed on the thread trimming cam 9. The forcing member 10 includes a forcing portion 10a located on the outer peripheral side of the thread trimming cam 9 and corresponding to the working protrusion 9a, and a receiving space 13 for accommodating the thread trimming roller 7 is formed between the forcing portion 10a and the working protrusion 9a. When the thread trimming roller 7 abuts against the working protrusion 9a, there is a gap between the forcing portion 10a and the thread trimming roller 7. The forcing portion 10a is in the shape of a hook bent toward the thread trimming cam 9. The forcing member 10 also includes a fixing portion 10c fixedly connected to the thread trimming cam 9, and a transition portion 10b is connected between the fixing portion 10c and the forcing portion 10a. The fixing portion 10c is provided with a side wing plate 10d, which is abutted against the end surface of the thread trimming cam 9 and fixedly connected. The side wing plate 10d is fixedly connected to the thread trimming cam 9 by a fixing screw 12, and there are two fixing screws 12 arranged along the circumference of the thread trimming cam 9. A positioning screw 11 is threadedly connected to one side of the working protrusion 9a on the outer circumference of the thread trimming cam 9, and a positioning hole 10e corresponding to the positioning screw 11 is opened on the fixing portion 10c, and the positioning screw 11 is inserted into the positioning hole 10e. The positioning screw 11 is also used to fix the thread trimming cam 9 to the rotating shaft 6a of the motor 6. The thread trimming cam 9 is sleeved on the rotating shaft 6a of the motor 6, and the positioning screw 11 is threadedly connected to the thread trimming cam 9. The inner end of the positioning screw 11 extends out of the thread trimming cam 9 and abuts against the outer side of the rotating shaft 6a of the motor 6. The outer peripheral surface of the thread trimming cam 9 has a base circular surface 9b on the other side of the working protrusion 9a. When the thread trimming roller 7 abuts against the base circular surface 9b, the thread trimming mechanism does not move, and when the thread trimming roller 7 abuts against the working protrusion 9a, the thread trimming mechanism operates.

[0029] When cutting the thread, Figure 3 and Figure 4As shown, the thread trimming cam 9 rotates clockwise, the thread trimming roller 7 enters the accommodating space 13, the thread trimming roller 7 abuts against the working protrusion 9a of the thread trimming cam 9 and moves, and there is a gap between the thread trimming roller 7 and the forcing portion 10a. After the thread trimming is completed, the thread trimming cam 9 rotates in the reverse direction. Figure 5 As shown, when the thread cutter 5 can be normally reset, under the action of the torsion spring 8, the thread cutting roller 7 abuts against the working protrusion 9a and moves in the reverse direction, moving out of the accommodating space 13 until it is reset to the position shown in FIG. Figure 3 When the thread cutter 5 gets stuck after cutting the thread and cannot be reset normally, Figure 6 As shown in the figure, the thread trimming cam 9 rotates while the thread trimming roller 7 does not move. As the thread trimming cam 9 rotates, the thread trimming roller 7 separates from the working protrusion 9a and abuts against the forcing portion 10a. The forcing portion 10a acts on the thread trimming roller 7 to force the thread trimming roller 7 to move and drive the thread trimming crank 2 to rotate, so as to release the stuck state of the thread trimmer 5 after the thread trimming. Then, under the action of the torsion spring 8, as shown in FIG. Figure 5 As shown, the thread trimming roller 7 abuts against the thread trimming cam 9 again to achieve forced reset. Therefore, the thread trimming forced reset structure of the sewing machine can force the thread trimmer 5 to reset when it is stuck and cannot be reset normally after thread trimming, thereby ensuring the normal use of the thread trimming mechanism.

[0030] The specific embodiments described herein are merely examples of the spirit of the present invention. A person skilled in the art of the present invention may make various modifications or additions to the specific embodiments described or replace them in a similar manner, but this will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A sewing machine thread trimming forced reset structure, comprising a rotatable thread trimming cam (9), wherein the outer peripheral surface of the thread trimming cam (9) has a working convex portion (9a) for the thread trimming roller (7) to abut against, characterized in that: A forcing member (10) is fixed on the thread trimming cam (9), and the forcing member (10) comprises a forcing portion (10a) located on the outer peripheral side of the thread trimming cam (9) and corresponding to the working protrusion (9a), and an accommodating space (13) for accommodating the thread trimming roller (7) is formed between the forcing portion (10a) and the working protrusion (9a).

2. The sewing machine thread trimmer forced reset structure according to claim 1, characterized in that: When the thread trimming roller (7) abuts against the working protrusion (9a), a gap exists between the forcing portion (10a) and the thread trimming roller (7).

3. The sewing machine thread trimmer forced reset structure according to claim 1 or 2, characterized in that: The forcing portion (10a) is in the shape of a hook bent toward the thread trimming cam (9).

4. The sewing machine thread trimmer forced reset structure according to claim 1 or 2, characterized in that: The forcing member (10) further comprises a fixing portion (10c) fixedly connected to the thread trimming cam (9), and a transition portion (10b) is connected between the fixing portion (10c) and the forcing portion (10a).

5. The sewing machine thread trimmer forced reset structure according to claim 4, characterized in that: The fixing portion (10c) is provided with a side wing plate (10d), and the side wing plate (10d) is abutted against the end surface of the thread trimming cam (9) and fixedly connected.

6. The sewing machine thread trimmer forced reset structure according to claim 5, characterized in that: The side wing plate (10d) is fixedly connected to the thread trimming cam (9) via a fixing screw (12).

7. The sewing machine thread trimmer forced reset structure according to claim 4, characterized in that: A positioning screw (11) is threadedly connected on one side of the working convex portion (9a) on the outer peripheral surface of the thread trimming cam (9), and a positioning hole (10e) corresponding to the positioning screw (11) is opened on the fixing portion (10c), and the positioning screw (11) is inserted into the positioning hole (10e).

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