A thread taking-up mechanism for an overlock sewing machine and an overlock sewing machine

Abstract

The present invention provides a thread taking-up mechanism and an overlock sewing machine, wherein the thread taking-up mechanism comprises a machine needle and a lower curved needle, wherein the lower curved needle comprises a thread taking-up portion, a thread taking-up surface arranged on the thread taking-up portion, and a thread taking-up root portion located at the end portion of the thread taking-up surface; during the thread taking-up process, the machine needle moves upward, the lower curved needle swings toward the direction close to the machine needle, the thread taking-up portion hooks a thread loop of the machine needle, and the machine needle thread relatively slides toward the direction close to the thread taking-up root portion on the thread taking-up surface, and the lower curved needle comprises an initial thread taking-up point when the thread taking-up portion just hooks the thread loop, and a stop thread taking-up point when the thread taking-up ends; when the lower curved needle is at the stop thread taking-up point, a distance L between the thread taking-up root portion and the machine needle in the axial direction of the main shaft is -2.5 mm to 2.5 mm, so that at the end of the thread taking-up, the thread taking-up root portion is prevented from pulling the machine needle thread, or the thread taking-up amount of the machine needle thread pulled by the thread taking-up root portion is reduced, and a sudden increase in the thread taking-up amount is avoided during the thread taking-up process, thereby achieving stable and perfect thread taking-up of the machine needle thread, and better adaptive sewing of thin materials to thick materials can be achieved.

Description

Technical Field

[0001] The invention relates to a thread taking-up mechanism for an overlock sewing machine.

[0002] The invention also relates to an overlock sewing machine comprising the thread taking-up mechanism. Background Art

[0003] At present, the overlock sewing machine is equipped with a needle that can reciprocate up and down, a lower curved needle that can swing back and forth left and right, and an upper curved needle installed on one side of the needle, such as a hemming actuator of an overlock sewing machine disclosed in the specification of the Chinese invention application with the publication number CN101338494A. During the operation of the overlock sewing machine, when the needle moves upward, the lower curved needle swings to the right in the direction close to the needle, and the lower curved needle hooks the thread loop of the needle until the lower curved needle swings to the rightmost end of its movement stroke. Therefore, this process is the thread-receiving process of the overlock sewing machine. The lower curved needle cooperates with the needle and then combines with the thread take-up rod matched with the needle to realize the thread-receiving of the needle thread. Therefore, the needle, the lower curved needle, the thread take-up rod and other components also constitute the thread-receiving mechanism of the overlock sewing machine.

[0004] However, due to the matching structural features between the needle and the lower looper in the existing overlock sewing machine, as well as the structural features of the lower looper itself, the amount of thread taken up by the overlock sewing machine during the thread taking-up process presents a parabolic change trajectory, that is, the amount of thread taken up has a sudden change state of sharp increase, and the sudden change of the amount of thread taken up is usually caused by the thread taking-up root on the lower looper excessively pulling the needle thread, resulting in unstable thread taking-up. Therefore, when the overlock sewing machine is sewing fabrics of different thicknesses, even by adjusting the thread take-up lever and the matching of the lower looper, it is impossible to achieve a wide range of adaptable sewing quality. During the sewing process, it is necessary to adjust the thread tension of the needle thread and the looper thread respectively according to the fabrics of different thicknesses through the thread clamp, so as to meet the sewing quality requirements, but this has certain technical requirements for the sewing operator and is difficult to achieve. Usually, when sewing thin materials, excessive thread taking-up will cause the fabric to wrinkle, and when sewing thick materials, insufficient thread taking-up will make the fabric taking-up unstable, thereby failing to achieve perfect thread taking-up of the needle thread and adaptive sewing of thin and thick materials. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a wire-reeling mechanism which can achieve stable wire-reeling.

[0006] To achieve the above-mentioned purpose, the present invention provides a thread-taking mechanism for an overlock sewing machine, comprising a needle capable of reciprocating up and down, and a lower curved needle capable of swinging back and forth toward or away from the needle, the lower curved needle comprising a thread-taking portion, a thread-taking surface provided on the thread-taking portion, and a thread-taking root portion located at the end of the thread-taking surface portion; during the thread-taking process, the needle moves upward, the lower curved needle swings toward the needle, the thread-taking portion hooks a thread loop of the needle, and the needle thread passed through the needle slides relatively toward the thread-taking root portion on the thread-taking surface portion, the lower curved needle comprising an initial thread-taking point when the thread-taking portion just hooks the thread loop, and a stop thread-taking point when the thread-taking ends; when the lower curved needle is at the stop thread-taking point, the distance L between the thread-taking root portion on the lower curved needle and the needle in the axial direction of the main shaft is -2.5 mm to 2.5 mm.

[0007] Furthermore, when the lower looper is at the stop thread-receiving point, the distance L between the thread-receiving root of the lower looper and the needle in the axial direction of the main shaft is 0 to 2.5 mm.

[0008] Furthermore, when the lower looper is at the initial take-up point, the angle α between the take-up surface on the lower looper and the needle is 61° to 64°; when the lower looper is at the stop take-up point, the angle α between the take-up surface on the lower looper and the needle is 82° to 85°.

[0009] Furthermore, when the lower looper is at the initial take-up point, the angle α between the take-up surface on the lower looper and the needle is 63°; when the lower looper is at the stop take-up point, the angle α between the take-up surface on the lower looper and the needle is 84°.

[0010] Furthermore, a thread loop groove is provided on the machine needle; during the thread taking-up process, the thread taking-up portion on the lower curved needle passes through the thread loop groove on the machine needle and hooks the thread loop of the machine needle.

[0011] As described above, the thread take-up mechanism and the overlock sewing machine according to the present invention have the following beneficial effects:

[0012] The present application controls the horizontal distance L between the thread taking-up root of the lower curved needle and the needle within the range of -2.5mm to 2.5mm when the thread taking-up point is stopped, so as to avoid the thread taking-up root from pulling the needle thread at the end of thread taking-up, or reduce the amount of thread taking-up by the thread taking-up root, and avoid the thread taking-up root from pulling the needle thread excessively and sharply, thereby avoiding a sharp increase in the amount of thread taking-up during the thread taking-up process, thereby achieving stable and perfect thread taking-up of the needle thread, and better realizing adaptive sewing of thin to thick materials, greatly improving the sewing performance of the entire overlock sewing machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the overlock sewing machine in this application.

[0014] Figure 2 This is a schematic diagram of the structure of the machine needle in this application.

[0015] Figure 3 It is a schematic diagram of the structure of the lower bending needle in this application.

[0016] Figure 4 This is a schematic diagram of the coordination between the machine needle and the lower bending needle at the initial thread-retrieving point in this application.

[0017] Figure 5 This is a schematic diagram of the coordination between the machine needle and the lower bending needle at the stop thread collection point in this application.

[0018] Component number description

[0019] 1 Needle

[0020] 11 Wire loop groove

[0021] 2 Lower Looper

[0022] 21. Take-up

[0023] 22 Take-up surface

[0024] 23 Thread root

[0025] 3 Spindle

[0026] 4 Needle bar

[0027] 5 Looper shaft

[0028] 6 Looper seat DETAILED DESCRIPTION

[0029] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0030] It should be noted that the structures, proportions, sizes, etc. drawn in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0031] The present application provides a kind of overlock sewing machine, such as Figure 1As shown, the overlock sewing machine is equipped with a main shaft 3 that can rotate and extend left and right, a needle bar 4 that can reciprocate up and down, a machine needle 1 installed at the lower end of the needle bar 4, a needle bar driving mechanism connected between the main shaft 3 and the needle bar 4, a lower looper 2 that can swing back and forth in a direction close to or away from the machine needle 1, and a looper driving mechanism connected between the main shaft 3 and the lower looper 2. The looper driving mechanism mainly includes a looper shaft 5 that is rotatably installed in the overlock sewing machine housing, a looper seat 6, and a swing transmission assembly connected between the looper shaft 5 and the main shaft 3. The looper shaft 5 extends forward and backward and is perpendicular to the main shaft 3, and the looper shaft 5 is located below the main shaft 3. The lower end of the looper seat 6 is fixed to the looper shaft 5 by screws, and the lower end of the lower looper 2 is fixed to the looper seat 6 by screws. When the overlock machine is sewing, the main shaft 3 rotates, and the main shaft 3 drives the needle bar 4 to reciprocate up and down through the needle bar driving mechanism, and the needle bar 4 drives the machine needle 1 to reciprocate up and down; at the same time, the main shaft 3 drives the bending needle shaft 5 to swing back and forth around its axis through the swing transmission assembly, and the bending needle shaft 5 drives the bending needle seat 6 and the lower bending needle 2 to swing back and forth together.

[0032] Furthermore, the present application also provides a thread take-up mechanism for an overlock sewing machine, such as Figure 1 As shown, the thread take-up mechanism includes the above-mentioned needle 1 and the lower looper 2. Figure 2 As shown, the needle 1 is provided with a thread loop groove 11, and the thread loop groove 11 is opened on the rear surface of the needle 1; Figure 2 As shown, the lower looper 2 has a wire taking-up portion 21, a wire taking-up surface 22 disposed on the wire taking-up portion 21, and a wire taking-up root 23 located at the left end of the wire taking-up surface 22. The wire taking-up surface 22 is an inclined surface with the right end inclined toward the upper right, and the wire taking-up root 23 is an arc segment. When the overlock machine is sewing, the needle 1 reciprocates up and down, and the lower looper 2 swings back and forth left and right, so the needle 1 has an upper stop position located at the uppermost end of its travel range, and a lower stop position located at the lowermost end of its travel range, and the lower looper 2 has a left limit position located at the leftmost end of its travel range, and a right limit position located at the rightmost end of its travel range; the coordination relationship between the needle 1 and the lower looper 2 is: when the needle 1 is in the upper stop position, the lower looper 2 is in the right limit position; when the needle 1 moves downward from the upper stop position to the lower stop position, the lower looper 2 swings to the left from the right limit position away from the needle 1 to the left limit position; when the needle 1 is in the lower stop position, the lower looper 2 is in the left limit position; when the needle 1 moves upward from the lower stop position to the upper stop position, the lower looper 2 swings to the right from the left limit position toward the direction close to the needle 1 to the right limit position.

[0033] Furthermore, during the upward movement of the needle 1 and the rightward swing of the lower looper 2, the thread take-up portion 21 on the lower looper 2 passes through the thread loop groove 11 on the needle 1 and hooks the thread loop of the needle 1, and the lower looper 2 drives the thread loop to swing to the right together, and the needle thread passing through the needle 1 slides relatively toward the thread take-up root 23 on the thread take-up surface 22 of the lower looper 2, and the lower looper 2 and the needle 1 cooperate to achieve the take-up of the needle thread. Therefore, during the upward movement of the needle 1 and the rightward swing of the lower looper 2, the thread take-up mechanism also performs the thread take-up action, generating a thread take-up process; when the thread take-up portion 21 just hooks the thread loop of the needle 1, the thread take-up process begins; when the thread take-up portion 21 drives the thread loop of the needle 1 to move to the right to the right limit position of the lower looper 2, the thread take-up process ends. Therefore, during the process of winding up, the lower looper 2 has an initial winding point and a stopping winding point. The angle α between the winding surface 22 on the lower looper 2 and the needle 1 changes all the time. The distance L between the winding root 23 on the lower looper 2 and the needle 1 in the axial direction of the main shaft 3 also changes all the time.

[0034] In particular, when the lower looper 2 stops at the take-up point, Figure 5As shown, the distance L between the thread take-up root 23 on the lower looper 2 and the sewing needle 1 in the axial direction of the main shaft 3 is -2.5mm to 2.5mm, and the distance L is also the horizontal distance between the right end of the thread take-up root 23 on the lower looper 2 connected to the thread take-up surface 22 and the sewing needle 1 in the left-right direction. When there are multiple sewing needles 1, the multiple sewing needles 1 are arranged side by side along the axial direction of the main shaft 3, and the above distance L is the horizontal distance between the thread take-up root 23 on the lower looper 2 and the leftmost sewing needle 1 in the left-right direction. When the distance L is a negative number in the range of -2.5mm to 0, it means that when the lower looper 2 stops winding, the right end of the winding root 23 on the lower looper 2 has crossed the needle 1 to the right. At this time, at the end of the winding process, the winding root 23 on the lower looper 2 will pull the needle thread and generate the winding amount. The winding root 23 plays a certain role in winding, but because the distance L is -2.5mm to 0, the winding amount of the needle thread by the winding root 23 is very small and will not cause a sharp increase in the winding amount. The change in the winding amount during the winding process is always relatively gentle. When the distance L is a positive number in the range of 0 to 2.5 mm, it means that when the lower looper 2 is at the stop winding point, the right end of the winding root 23 on the lower looper 2 has not crossed the needle 1 to the right and is still located on the left side of the needle 1. At this time, at the end of the winding process, the needle thread is still pulled by the winding surface 22 to generate the winding amount. In other words, in the winding process, the wire is only pulled by the winding surface 22, and the wire is not pulled by the winding root 23. The winding root 23 does not play a role in winding, and the winding amount of the winding root 23 is 0. Therefore, the winding amount changes linearly and there is no obvious mutation. Therefore, the present application controls the horizontal distance L between the thread taking-up root 23 of the lower curved needle 2 and the needle 1 within the range of -2.5mm to 2.5mm when the thread taking-up point is stopped, so as to avoid the thread taking-up root 23 pulling the needle thread at the end of thread taking-up, or reduce the amount of thread taking-up by the thread taking-up root 23, thereby avoiding the thread taking-up root 23 from pulling the needle thread excessively and sharply, thereby avoiding a sudden increase in the thread taking-up amount during the thread taking-up process, thereby achieving stable and perfect thread taking-up of the needle thread, and better realizing adaptive sewing of thin to thick materials, greatly improving the sewing performance of the whole overlock sewing machine.

[0035] Preferably, when the lower looper 2 is at the stop thread collection point, the distance L between the thread collection root 23 on the lower looper 2 and the needle 1 in the axial direction of the main shaft 3 is 0-2.5 mm, and the best is 0 mm. In addition, the thread collection root 23 is a circular arc segment of 145° to 155°, and the radius is 0.7mm to 0.8mm; optimally, the thread collection root 23 is a circular arc segment of 150°, and the radius is 0.75mm.

[0036] Further, when the lower looper 2 is at the initial take-up point, as Figure 4As shown in FIG. 1 , the thread take-up portion 21 on the lower looper 2 has just hooked the thread loop of the needle 1. At this time, the angle α between the thread take-up surface 22 on the lower looper 2 and the needle 1 (referring to the central axis of the needle 1) is 61° to 64°; as the lower looper 2 continues to swing to the right, the angle α between the thread take-up surface 22 on the lower looper 2 and the needle 1 gradually increases; when the lower looper 2 is at the thread take-up stop point, as shown in FIG. Figure 5 As shown, the thread take-up portion 21 on the lower looper 2 drives the thread loop of the machine needle 1 to move rightward to the right limit position of the lower looper 2. At this time, the angle α between the thread take-up surface 22 on the lower looper 2 and the machine needle 1 is 82° to 85°. The present application defines the horizontal distance L between the thread take-up root 23 of the lower looper 2 and the machine needle 1 at the stop thread take-up point, and also defines the position angle relationship between the thread take-up surface 22 on the lower looper 2 and the machine needle 1 at the initial thread take-up point and the stop thread take-up point, so that the change of the angle α between the thread take-up surface 22 on the lower looper 2 and the machine needle 1 is always maintained at about 21° during the thread take-up process, thereby making the thread take-up surface 22 on the lower looper 2 always maintain a uniform and linear thread take-up amount for the thread take-up of the machine needle thread, that is, during the thread take-up process, the thread take-up amount of the machine needle thread by the thread take-up surface 22 is linearly and gradually increased, and there is no sudden change in thread take-up state. In combination with the thread take-up lever mechanism on the overlock sewing machine, the machine needle thread can be stably and perfectly taken up. When sewing simple fabrics of different thicknesses, it is basically unnecessary for the sewing worker to adjust the thread tension of the needle thread and the looper thread. Preferably, in this embodiment, when the lower looper 2 is at the initial thread collection point, the angle α between the upper thread collection surface 22 of the lower looper 2 and the needle 1 is 63°; when the lower looper 2 is at the stop thread collection point, the angle α between the upper thread collection surface 22 of the lower looper 2 and the needle 1 is 84°.

[0037] In summary, the overlock sewing machine involved in the present application can better achieve the adaptability of sewing from thin materials (such as thin mesh fabrics) to thick materials (such as thick denim fabrics), as well as perfect quality sewing, greatly improving the sewing performance of the overlock sewing machine. In addition, the present application does not change the component structure of the overlock sewing machine, so the materials and processing technology used in the production of the machine needle 1 and the lower looper 2 are basically the same as before, and no additional costs will be incurred, so that the present application can greatly improve the adaptability of the overlock sewing machine to thin and thick materials and the sewing performance at a very low cost. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0038] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A thread take-up mechanism for an overlock sewing machine, comprising a needle (1) capable of reciprocating up and down, and a lower looper (2) capable of reciprocatingly swinging toward or away from the needle (1), the lower looper (2) comprising a thread take-up portion (21), a thread take-up surface (22) disposed on the thread take-up portion (21), and a thread take-up root (23) located at the end of the thread take-up surface (22); during the thread take-up process, the needle (1) moves upward, the lower looper (2) swings toward the needle (1), the thread take-up portion (21) hooks the thread loop of the needle (1), and the needle thread inserted in the needle (1) slides relatively toward the thread take-up root (23) on the thread take-up surface (22), the lower looper (2) comprises an initial thread take-up point when the thread take-up portion (21) just hooks the thread loop, and a stop thread take-up point when the thread take-up is finished, characterized in that: When the lower looper (2) is at the thread-receiving stop point, the distance L between the thread-receiving root (23) on the lower looper (2) and the machine needle (1) in the axial direction of the main shaft (3) is -2.5 mm to 2.5 mm; When the lower looper (2) is at the initial thread-receiving point, the angle α between the upper thread-receiving surface (22) of the lower looper (2) and the sewing needle (1) is 61° to 64°; when the lower looper (2) is at the stop thread-receiving point, the angle α between the upper thread-receiving surface (22) of the lower looper (2) and the sewing needle (1) is 82° to 85°; The machine needle (1) is provided with a thread loop groove (11); during the thread taking-up process, the thread taking-up portion (21) on the lower looper (2) passes through the thread loop groove (11) on the machine needle (1) and hooks the thread loop of the machine needle (1).

2. The thread take-up mechanism for an overlock sewing machine according to claim 1, characterized in that: When the lower looper (2) is at the thread-receiving stop point, the distance L between the thread-receiving root (23) on the lower looper (2) and the machine needle (1) in the axial direction of the main shaft (3) is 0 to 2.5 mm.

3. The thread take-up mechanism for an overlock sewing machine according to claim 1, characterized in that: When the lower looper (2) is at the initial thread-receiving point, the angle α between the upper thread-receiving surface (22) of the lower looper (2) and the machine needle (1) is 63°; when the lower looper (2) is at the stop thread-receiving point, the angle α between the upper thread-receiving surface (22) of the lower looper (2) and the machine needle (1) is 84°.

4. An overlock sewing machine, characterized in that: The overlock sewing machine is equipped with a thread take-up mechanism as described in any one of claims 1 to 3.

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