Automatic thread trimming and thread loosening preventing mechanism for sewing machine

Abstract

The invention discloses an automatic thread-trimming and thread-loosening-preventing mechanism for a sewing machine, which adopts an integrated structure that a cam is driven by a single motor, adopts a single power source to synchronously control thread-trimming and thread-clamping actions, replaces a traditional electromagnet system and has a sewing-starting and thread-loosening-preventing function. In the invention, the thread loosening end and the presser foot lifting end of the cam are independently designed in a layered manner, so that compact integration of mechanical transmission is realized, the size of a machine head is obviously reduced, and after an electromagnet control scheme is replaced, the defects of high noise, easiness in heating and the like can be overcome; in addition, a thread clamping action is supplemented for a conventional sewing process, the motor controls the thread clamping assembly to clamp a free-state thread end after the thread cutting action is completed, it is ensured that the next sewing starting action can accurately complete the thread hooking action, and the phenomena of thread loosening and thread flying are prevented.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewing machine technical field, specifically to an automatic thread cutting and anti-thread shedding mechanism for a sewing machine. BACKGROUND

[0002] The roller sewing machine is a general term for a special sewing equipment in the textile industry, and is widely used in the field of thick material sewing such as leather, shoes, bags, canvas, etc. There are many types of roller sewing machines on the market, such as servo direct drive roller sewing machine, three automatic roller sewing machine, three-step roller sewing machine, etc., which are mainly used in shoe, bag and car cushion manufacturing enterprises. In the conventional shoe machine market, the sewing machine will use the automatic thread cutting function after sewing is completed. The traditional sewing machine thread cutting mechanism is driven by an electromagnet. The structure driven by the electromagnet has defects such as large space occupation, loud noise, easy heating, low parameter adjustment freedom, high size precision requirement of the thread cutting cam, high assembly requirement, inaccurate and troublesome adjustment, and low production efficiency.

[0003] In addition, the traditional sewing machine thread cutting mechanism will leave a thread end on the needle after cutting the thread. The thread end in the free state has no tension, and the shuttle may not hook the thread to form a thread loop with a certain probability during the next sewing, resulting in thread shedding and flying of the first few stitches before sewing, which seriously affects the product quality and production efficiency. SUMMARY

[0004] Therefore, in order to solve the above problems, the purpose of the present application is to provide an automatic thread cutting and anti-thread shedding mechanism for a sewing machine, comprising:

[0005] a motor;

[0006] a cam connected to the output end of the motor;

[0007] a frame provided with a thread clamping assembly and a thread cutting assembly;

[0008] The cam includes a thread cutting trigger part and a thread clamping trigger part, the thread cutting trigger part is connected to the thread cutting assembly through a thread cutting link set, and the thread clamping trigger part is connected to the thread clamping assembly through a thread clamping link set.

[0009] The motor is used to control the rotation of the cam. When the cam rotates clockwise, the thread cutting trigger end pulls the thread cutting link set to control the thread cutting assembly to complete the thread cutting action. When the cam rotates counterclockwise, the thread clamping trigger end pulls the thread clamping link set to control the thread clamping assembly to complete the thread clamping action.

[0010] Preferably, the thread cutting trigger part includes a first rotary groove, a first sliding block is slidingly connected in the first rotary groove, the first sliding block is rotatably connected to the thread cutting link set, and the first sliding block is used to control the movement of the thread cutting link set.

[0011] Preferably, the shearing wire rod set comprises a shearing wire swing arm, a shearing wire sleeve ring and a shearing wire connecting rod, two ends of the shearing wire swing arm are connected to a shearing wire trigger end and the shearing wire connecting rod respectively, and an inner edge of the shearing wire sleeve ring is fixed to the shearing wire assembly, and an outer edge of the shearing wire sleeve ring is rotationally connected to the shearing wire connecting rod.

[0012] Preferably, the shearing wire assembly comprises a shearing wire shaft and a shearing wire cutter, the shearing wire shaft is fixed to the shearing wire sleeve ring, an upper end of the shearing wire shaft is fixed with a driving gear, the shearing wire cutter is rotationally connected to the rack through a cutter shaft, a driven gear is fixed to the cutter shaft, and the driving gear is engaged with the driven gear.

[0013] Preferably, the clamping wire trigger part comprises a second rotary groove, a second sliding block is slidingly connected in the second rotary groove, the second sliding block is rotationally connected to the clamping wire rod set, and the second sliding block is used for controlling the clamping wire rod set to move.

[0014] Preferably, the clamping wire rod set comprises a clamping wire swing arm one, a clamping wire swing arm two and a clamping wire connecting rod, two ends of the clamping wire swing arm one are connected to a clamping wire trigger end and the clamping wire connecting rod respectively, and two ends of the clamping wire swing arm two are connected to the clamping wire assembly and the clamping wire connecting rod respectively.

[0015] Preferably, the clamping wire assembly comprises a clamping wire support, a clamping wire plate and a clamping wire shaft, the lower end of the clamping wire shaft is connected to the clamping wire swing arm two, the clamping wire support is fixed to the clamping wire shaft, and the clamping wire plate is fixed to the rack.

[0016] Preferably, the lower end of the clamping wire shaft is eccentrically provided with a third sliding block, one end of the clamping wire swing arm two is provided with a sliding groove, and the third sliding block is clamped in the sliding groove and can move in the sliding groove.

[0017] Preferably, the rack is fixed with a first limiting column and a second limiting column, the clamping wire swing arm one is provided with a first limiting groove matched with the first limiting column, and the clamping wire swing arm two is provided with a second limiting groove matched with the second limiting column.

[0018] Preferably, the rack is connected with a first spring and a second spring, the first spring is connected to the shearing wire connecting rod, and the second spring is connected to the clamping wire connecting rod.

[0019] The present application has the following beneficial effects:

[0020] The application synchronously controls the thread cutting and clamping actions by the single power source through the single motor driving cam integrated structure, replaces the traditional electromagnet system, and has the thread starting anti-dropping function. In the application, the thread cutting end and the presser foot lifting end of the cam are designed independently in layers, the compact integration of the mechanical transmission is realized, the machine head volume is significantly reduced, and after the scheme of replacing the electromagnet control, the defects of large noise and easy heating are solved; the application also supplements a thread clamping action to the conventional sewing process, the thread end in the free state after the thread cutting action is completed by the motor control thread clamping assembly, the next thread starting action can accurately complete the thread hooking action, and the thread dropping and flying phenomena are prevented. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0022] Figure 1 The structural schematic diagram of the application;

[0023] Figure 2 The structural schematic diagram of the hidden part of the rack of the application;

[0024] Figure 3 The structural schematic diagram of the cam;

[0025] Figure 4 The structural schematic diagram of the cam from another angle;

[0026] Figure 5 The structural schematic diagram of the thread cutting assembly;

[0027] Figure 6 The structural schematic diagram of the thread cutting assembly from another angle;

[0028] Figure 7 The structural schematic diagram of the thread clamping assembly;

[0029] Figure 8 The structural schematic diagram of the thread clamping assembly from another angle;

[0030] Figure 9 The structural schematic diagram of the thread cutting assembly and the thread clamping assembly;

[0031] Figure 10 The structural schematic diagram of the application;

[0032] Explanation of reference numerals: 1, frame; 11, first limiting column; 12, second limiting column; 13, first spring; 14, second spring; 2, motor; 21, cam; 211, first rotary groove; 212, second rotary groove; 213, first sliding block; 214, second sliding block; 3, thread shearing assembly; 31, thread shearing shaft; 32, thread shearing cutter; 33, driving gear; 34, driven gear; 4, thread shearing lever assembly; 41, thread shearing swing arm; 42, thread shearing sleeve ring; 43, thread shearing connecting rod; 5, thread clamping assembly; 51, thread clamping support; 52, thread clamping plate; 53, thread clamping shaft; 531, third sliding block; 6, thread clamping lever assembly; 61, thread clamping swing arm I; 62, thread clamping swing arm II; 621, sliding groove; 63, thread clamping connecting rod; 64, first limiting groove; 65, second limiting groove.

[0033] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application.

[0035] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0036] Unless otherwise clearly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0037] Example 1

[0038] Figures 1-10The application provides an automatic thread cutting and preventing thread falling mechanism for a sewing machine, which comprises a rack 1, a motor 2, a sewing machine head, the sewing machine head and the motor 2 are both mounted on the rack 1, the sewing mechanism comprises a thread cutting assembly 3 and a thread clamping assembly 5, the motor 2 is connected with a cam 21, the motor 2 can control the rotation of the cam 21, the cam 21 comprises a thread cutting trigger part and a thread clamping trigger part, the thread cutting trigger part is connected with the thread cutting assembly 3 through a thread cutting link group 4, the thread clamping trigger part is connected with the thread clamping assembly 5 through a thread clamping link group 6, when the motor 2 controls the cam 21 to rotate clockwise, the thread cutting trigger end pulls the thread cutting link group 4 to control the thread cutting assembly 3 to complete the thread cutting action, when the motor 2 controls the cam 21 to rotate counterclockwise, the thread clamping trigger end pulls the thread clamping link group 6 to control the thread clamping assembly 5 to complete the thread clamping action.

[0039] It should be noted that the thread cutting action and the thread clamping action are alternately performed, the control system controls the motor 2 to control the cam 21 to perform the thread cutting action or the thread clamping action according to the set program, and the two actions will not conflict with each other.

[0040] The thread cutting trigger part and the thread clamping trigger part are integrated in the cam 21 body, wherein the thread cutting trigger part is provided with a first rotary groove 211, and the thread clamping trigger part is provided with a second rotary groove 212. A first sliding block 213 is slidingly and fitly installed in the first rotary groove 211, the first sliding block 213 is rotationally connected with the thread cutting link group 4, and is used for converting the rotary motion of the cam 21 into the moving action of the thread cutting link group 4; similarly, a second sliding block 214 is slidingly and fitly installed in the second rotary groove 212, the second sliding block 214 is rotationally connected with the thread clamping link group 6, and is used for converting the rotary motion of the cam 21 into the moving action of the thread clamping link group 6. The first rotary groove 211 and the second rotary groove 212 both adopt the same geometric shape, which specifically shows that the two rotary grooves both have a near-point end and a far-point end, wherein the radial distance of the near-point end from the rotation center of the cam 21 is less than that of the far-point end. When the cam 21 is controlled to rotate, the first sliding block 213 and the second sliding block 214 respectively slide in the corresponding rotary grooves, and the motion trajectories thereof cover the conversion interval from the near-point end to the far-point end. The displacement of the first sliding block 213 and the second sliding block 214 is further converted into the moving action of the thread cutting link group 4 and the thread clamping link group 6 through the hinged relationship between the sliding blocks and the link groups, so as to realize the independent control of the thread cutting action and the thread clamping action.

[0041] The cutting thread rod component group 4 comprises a cutting thread swing arm 41, a cutting thread sleeve ring 42 and a cutting thread connecting rod 43. The two ends of the cutting thread swing arm 41 are connected to a cutting thread trigger end and the cutting thread connecting rod 43 respectively. The inner edge of the cutting thread sleeve ring 42 is fixed to the cutting thread assembly 3. The outer edge of the cutting thread sleeve ring 42 is rotationally connected to the cutting thread connecting rod 43. The cutting thread assembly 3 comprises a cutting thread shaft 31 and a cutting thread cutter 32. The lower end of the cutting thread shaft 31 is fixed to the cutting thread sleeve ring 42. The upper end of the cutting thread shaft 31 is fixed with a driving gear 33. The cutting thread cutter 32 is rotationally connected to the rack 1 through a cutter shaft. The cutter shaft is fixed with a driven gear 34. The driving gear is engaged with the driven gear 34. When the cutting thread shaft 31 rotates, the driving gear rotates together. The driving gear drives the driven gear 34 engaged therewith to rotate. The driven gear 34 rotates together with the cutting thread cutter 32. The rotation of the cutting thread cutter 32 can cut the sewing thread.

[0042] The clamping thread rod component group 6 comprises a clamping thread swing arm one 61, a clamping thread swing arm two 62 and a clamping thread connecting rod 63. The two ends of the clamping thread swing arm one 61 are connected to a clamping thread trigger end and the clamping thread connecting rod 63 respectively. The two ends of the clamping thread swing arm two 62 are connected to the clamping thread assembly 5 and the clamping thread connecting rod 63 respectively. The clamping thread assembly 5 comprises a clamping thread support 51, a clamping thread plate 52 and a clamping thread shaft 53. The lower end of the clamping thread shaft 53 is connected to the clamping thread swing arm two 62. The clamping thread support 51 is fixed to the clamping thread shaft 53. The clamping thread plate 52 is fixed to the rack 1. When the clamping thread shaft 53 rotates, the clamping thread support 51 rotates together. After the clamping thread support 51 rotates, it approaches the fixed clamping thread plate 52, thereby clamping the thread end in a free state.

[0043] The lower end of the clamping thread shaft 53 is provided with a third sliding block 531. The third sliding block 531 is offset from the rotation center axis of the clamping thread shaft 53. One end of the clamping thread swing arm two 62 is provided with a sliding groove 621. The third sliding block 531 is clamped in the sliding groove 621 and can move in the sliding groove 621. When the clamping thread swing arm two 62 rotates, it drives the third sliding block 531 to rotate along the rotation center of the clamping thread shaft 53, thereby driving the clamping thread shaft 53 to rotate.

[0044] It should be noted that the clamping thread shaft 53 and the cutting thread shaft 31 are of a nested structure. The mechanical movements of the two do not interfere with each other. Specifically, the clamping thread shaft 53 is arranged in the cutting thread shaft 31. A ball sliding structure is arranged between the two, which greatly reduces the friction force, so that one of the clamping thread shaft 53 and the cutting thread shaft 31 does not drive the other to rotate at any time when it rotates. For details, please refer to Figure 10 .

[0045] The first limiting column 11 and the second limiting column 12 are fixed on the rack 1, the first limiting slot 64 of the first wire clamping swing arm 61 is matched with the first limiting column 11, and the second limiting slot 65 of the second wire clamping swing arm 62 is matched with the second limiting column 12. Specifically, the first limiting column 11 and the second limiting column 12 are respectively clamped in the first limiting slot 64 and the second limiting slot 65, and the first wire clamping swing arm 61 and the second wire clamping swing arm 62 are limited by the first limiting column 11 and the second limiting column 12 when rotating, and can only swing within a specified angle range, so as to avoid that the first wire clamping swing arm 61 and the second wire clamping swing arm 62 exceed the limited swing distance, and the wire clamping support 51 excessively approaches the wire clamping plate 52 and collides and is damaged.

[0046] The first spring 13 and the second spring 14 are connected to the rack 1, the first spring 13 is connected to the wire shearing connecting rod 43, and the second spring 14 is connected to the wire clamping connecting rod 63. The first spring 13 and the second spring 14 are respectively used to help the wire shearing assembly 3 and the wire clamping assembly 5 reset.

[0047] Workflow:

[0048] After the control system sends a wire shearing instruction, the motor 2 drives the cam 21 to rotate clockwise, and the wire shearing trigger part of the cam 21 pushes the first sliding block 213 to move; the first sliding block 213 pulls the wire shearing rod assembly 4 through the hinged connection, which is specifically manifested as that the wire shearing swing arm 41 drives the wire shearing connecting rod 43 to displace, the wire shearing connecting rod 43 drives the wire shearing sleeve 42 to swing, and then drives the wire shearing shaft 31 to rotate; the driving gear on the upper end of the wire shearing shaft 31 meshes with the driven gear 34, so that the wire shearing cutter 32 fixed to the cutter shaft rotates synchronously, and the wire material cutting is completed; after the wire shearing action is completed, the first spring 13 pulls the wire shearing connecting rod 43 to reset, so that the wire shearing assembly 3 returns to the initial position.

[0049] After the wire shearing is completed, the control system switches the instruction, the motor 2 drives the cam 21 to rotate counterclockwise, and the wire clamping trigger part of the cam 21 pushes the second sliding block 214 to move; the second sliding block 214 pulls the wire clamping rod assembly 6 through the hinged connection, which is specifically manifested as that the first wire clamping swing arm 61 drives the wire clamping connecting rod 63 to displace, and the wire clamping connecting rod 63 drives the second wire clamping swing arm 62 to swing; the second wire clamping swing arm 62 drives the third sliding block 531 to rotate through the sliding groove 621 thereof, the third sliding block 531 drives the wire clamping shaft 53 to rotate, the wire clamping support 51 fixed to the wire clamping shaft 53 swings to the direction of the fixed wire clamping plate 52, and clamps the wire head in the free state after the wire shearing; after the wire clamping action is completed, the second spring 14 pulls the wire clamping connecting rod 63 to reset, so that the wire clamping assembly 5 returns to the initial position.

[0050] Obviously, the above embodiments of the present application are merely exemplary but not intended to limit the embodiments of the present application. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the scope of the present application. It is not necessary or possible to enumerate all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. An automatic thread-cutting and anti-slipping mechanism for a sewing machine, characterized in that, include: Motor (2); Cam (21), which is connected to the output end of motor (2); A frame (1) is provided with a wire clamping assembly (5) and a wire cutting assembly (3); The cam (21) includes a wire-cutting trigger part and a wire-clamping trigger part. The wire-cutting trigger part is connected to the wire-cutting assembly (3) through a wire-cutting rod assembly (4), and the wire-clamping trigger part is connected to the wire-clamping assembly (5) through a wire-clamping rod assembly (6). The motor (2) is used to control the rotation of the cam (21). When the cam (21) rotates clockwise, the wire cutting trigger end pulls the wire cutting rod assembly (4) to control the wire cutting assembly (3) to complete the wire cutting action. When the cam (21) rotates counterclockwise, the wire clamping trigger end pulls the wire clamping rod assembly (6) to control the wire clamping assembly (5) to complete the wire clamping action.

2. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 1, characterized in that, The wire-cutting trigger part includes a first spiral groove (211), a first slider (213) is slidably connected in the first spiral groove (211), the first slider (213) is rotatably connected to the wire-cutting rod assembly (4), and the first slider (213) is used to control the movement of the wire-cutting rod assembly (4).

3. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 2, characterized in that, The wire cutting rod assembly (4) includes a wire cutting swing arm (41), a wire cutting collar (42), and a wire cutting connecting rod (43). The two ends of the wire cutting swing arm (41) are respectively connected to the wire cutting trigger end and the wire cutting connecting rod (43). The inner edge of the wire cutting collar (42) is fixed to the wire cutting assembly (3), and the outer edge of the wire cutting collar (42) is rotatably connected to the wire cutting connecting rod (43).

4. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 3, characterized in that, The wire cutting assembly (3) includes a wire cutting shaft (31) and a wire cutting cutter (32). The lower end of the wire cutting shaft (31) is fixed to the wire cutting collar (42), and the upper end of the wire cutting shaft (31) is fixed with a drive gear (33). The wire cutting cutter (32) is rotatably connected to the frame (1) through a cutter shaft. A driven gear (34) is fixed on the cutter shaft, and the drive gear meshes with the driven gear (34).

5. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 1, characterized in that, The wire clamping trigger part includes a second spiral groove (212), and a second slider (214) is slidably connected in the second spiral groove (212). The second slider (214) is rotatably connected to the wire clamping rod assembly (6), and the second slider (214) is used to control the movement of the wire clamping rod assembly (6).

6. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 5, characterized in that, The wire clamping rod assembly (6) includes a first wire clamping swing arm (61), a second wire clamping swing arm (62), and a wire clamping connecting rod (63). The two ends of the first wire clamping swing arm (61) are respectively connected to the wire clamping trigger end and the wire clamping connecting rod (63), and the two ends of the second wire clamping swing arm (62) are respectively connected to the wire clamping assembly (5) and the wire clamping connecting rod (63).

7. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 6, characterized in that, The wire clamping assembly (5) includes a wire clamping bracket (51), a wire clamping plate (52), and a wire clamping shaft (53). The lower end of the wire clamping shaft (53) is connected to the second wire clamping swing arm (62). The wire clamping bracket (51) is fixed to the wire clamping shaft (53), and the wire clamping plate (52) is fixed to the frame (1).

8. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 7, characterized in that, The lower end of the clamping shaft (53) is provided with a third slider (531) eccentrically, and one end of the clamping arm (62) is provided with a sliding groove (621). The third slider (531) is engaged in the sliding groove (621) and can move in the sliding groove (621).

9. The automatic thread-cutting and anti-slipping mechanism for a sewing machine according to claim 8, characterized in that, The frame (1) is fixed with a first limiting post (11) and a second limiting post (12). The first wire clamping arm (61) is provided with a first limiting groove (64) that cooperates with the first limiting post (11). The second wire clamping arm (62) is provided with a second limiting groove (65) that cooperates with the second limiting post (12).

10. The automatic thread-cutting and anti-slipping mechanism for a sewing machine according to claim 1, characterized in that, The frame (1) is connected to a first spring (13) and a second spring (14). The first spring (13) is connected to the wire cutting rod assembly (4), and the second spring (14) is connected to the wire clamping rod assembly (6).

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