Thread trimming mechanism of sewing machine

Abstract

The utility model provides a thread trimming mechanism of a sewing machine, and belongs to the technical field of sewing machines. A thread trimming mechanism of a sewing machine comprises a fixed cutter; the movable cutter assembly is matched with the fixed cutter, can translate relative to the fixed cutter and is used for trimming threads; the driving assembly is used for driving the moving cutter assembly to move back and forth, the driving assembly comprises a swing rod, the swing rod can swing around a first axis, one end of the swing rod is movably connected with the moving cutter assembly, and the swing rod is further provided with a contact assembly; a thread trimming cam is fixed to the transmission shaft and makes contact with the contact assembly, so that the swing rod can swing in the direction away from the fixed cutter; a push rod of the pusher is connected with the lower end of the contact assembly, and the pusher is used for enabling the swing rod to swing towards the fixed cutter.

Description

TECHNICAL FIELD

[0001] The utility model belongs to sewing machine technical field, especially a sewing machine's thread trimming mechanism. BACKGROUND

[0002] The thread trimming device built in the current zigzag sewing machine adopts more complex multi-rod transmission structure: through multiple transmission rods, the thread trimming cam on the transmission shaft drives the reciprocating movement of the moving knife assembly to realize thread trimming, but due to the multi-rod structure, the overall structure of the device is complex, and there are many inconveniences in assembly or maintenance, and the cost is higher. INVENTION CONTENTS

[0003] The utility model aims at the above problems existing in prior art, and provides a sewing machine's thread trimming mechanism, which has the characteristics of simple structure, stability and low cost.

[0004] The utility model can be realized by the following technical schemes:

[0005] A sewing machine's thread trimming mechanism, comprising:

[0006] A fixed knife;

[0007] A moving knife assembly, which cooperates with the fixed knife and can translate relative to the fixed knife to realize thread trimming;

[0008] A driving assembly, which is used to drive the moving knife assembly to move back and forth, and comprises:

[0009] A swing rod, which can swing around a first axis, one end of the swing rod is movably connected with the moving knife assembly, and a contact head assembly is further arranged on the swing rod;

[0010] A transmission shaft, which can rotate, the transmission shaft is fixed with a thread trimming cam, the thread trimming cam is in contact with the contact head assembly to enable the swing rod to swing towards the direction away from the fixed knife;

[0011] A pusher, the push rod of the pusher is connected with the lower end of the contact head assembly, and the pusher is used to swing the swing rod towards the direction of the fixed knife.

[0012] In the above-mentioned thread trimming mechanism, a linear guide rail is further included, the moving knife assembly comprises a moving knife body and a moving knife seat, the moving knife body is fixed on the moving knife seat, and the moving knife seat is fixed on the sliding block of the linear guide rail.

[0013] In the above-mentioned thread trimming mechanism, a fixed knife seat is further included, the fixed knife seat is provided with a guide groove, and the moving knife body is slidably arranged in the guide groove and passes through the guide groove.

[0014] In the above cutting mechanism, the fixed knife is detachably arranged on the fixed knife seat, and the fixed knife at least partially covers the guide groove, so as to limit the disengagement of the moving knife body from the guide groove.

[0015] In the above cutting mechanism, a limiting part is further arranged on the fixed knife seat, and the limiting part is used for limiting the movement of the moving knife seat towards the fixed knife.

[0016] In the above cutting mechanism, a guide hole is arranged on the swing rod, the moving knife assembly further comprises a connecting shaft and a guide block, the guide hole is arranged along the length direction of the swing rod, the guide block is rotatably arranged on the connecting shaft, the connecting shaft is arranged on the moving knife seat, and the guide block is arranged in the guide hole and can slide in the guide hole.

[0017] In the above cutting mechanism, the pusher is specifically an electromagnetic pusher or a telescopic cylinder.

[0018] In the above cutting mechanism, the contact assembly comprises a rotating ring and a rod body, the rod body is arranged on the swing rod, the rotating ring is rotatably arranged on the rod body and in contact with the cutting cam, the push rod end of the pusher is provided with a connecting block, the connecting block is provided with a movable hole, the lower end of the rod body is inserted into the movable hole, and the lower end of the rod body can translate in the movable hole.

[0019] In the above cutting mechanism, the cutting cam has an acting surface, the acting surface is arranged around the transmission shaft, the acting surface is in contact with the contact assembly, the acting surface has a plurality of annularly arranged first abutting surfaces and second abutting surfaces, the two ends of the first abutting surface are connected with the two ends of the second abutting surface through two transition surfaces, and the first abutting surface is closer to the pusher than the second abutting surface.

[0020] Compared with the prior art, the application has the following advantages:

[0021] Only three parts of the swing rod, the cutting cam and the pusher are used to realize the reciprocating motion, a plurality of transmission rods are not needed to be cascaded, the components are less, the structure is more stable, after the parts are reduced, the assembly steps are simple, the fault troubleshooting and component replacement are more convenient, the cutting cam-swing rod structure reduces the transmission error and the wear point, and the reliability is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a perspective view in the application;

[0023] Figure 2 is a partial enlarged structural view in the application;

[0024] Figure 3 is a partial enlarged structural view in another view of the application;

[0025] Figure 4 is a perspective view of the swing lever position in the present application;

[0026] Figure 5 is an exploded view of the swing lever position in the present application;

[0027] Figure 6 is an exploded view of the moving knife assembly in the present application;

[0028] in the figure,

[0029] A-A, first axis;

[0030] 2, fixed knife;

[0031] 3, moving knife assembly; 31, moving knife body; 32, moving knife seat; 33, connecting shaft; 34, guide block;

[0032] 4, driving assembly; 41, swing lever; 411, guide hole; 42, cutting line cam; 421, acting surface; 4211, first abutting surface; 4212, second abutting surface; 4213, transition surface; 43, transmission shaft; 44, pusher; 441, connecting block; 442, movable hole; 45, contact head assembly; 451, rotating ring; 452, rod body;

[0033] 5, fixed knife seat; 51, guide groove; 52, limiting part;

[0034] 6, linear guide rail; 61, sliding block;

[0035] 7, first fixed component;

[0036] 8, second fixed component. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0038] As Figures 1 to 6As shown, a thread cutting mechanism of a sewing machine, comprising: a fixed knife 2, a movable knife assembly 3, a driving assembly 4, the movable knife assembly 3 is matched with the fixed knife 2 and can be translated relative to the fixed knife 2 to realize thread cutting; the driving assembly 4 is used to drive the movable knife assembly 3 to move back and forth, the driving assembly 4 comprises: a swing rod 41, a rotatable transmission shaft 43, a pusher 44, the swing rod 41 can swing around a first axis A-A, one end of the swing rod 41 is movably connected with the movable knife assembly 3, and a contact assembly 45 is further arranged on the swing rod 41; the transmission shaft 43 is fixed with a thread cutting cam 42, the thread cutting cam 42 is in contact with the contact assembly 45 to enable the swing rod 41 to swing towards the direction away from the fixed knife 2; the push rod of the pusher 44 is connected with the lower end of the contact assembly 45, and the pusher 44 is used to make the swing rod 41 swing towards the direction of the fixed knife 2.

[0039] In the present application, the transmission shaft 43 in the driving assembly 4 drives the thread cutting cam 42 fixed thereon to rotate, with the rotation of the thread cutting cam 42, the convex part of the thread cutting cam 42 abuts against the contact assembly 45 on the swing rod 41 to make the swing rod 41 swing around the first axis away from the fixed knife 2, one end of the swing rod 41 drives the movable knife assembly 3 to move the movable knife relative to the fixed knife 2 to a cutting position to complete the thread cutting action; when the thread cutting cam 42 rotates to the concave part, the contact assembly 45 pushes the swing rod 41 to swing towards the direction of the fixed knife 2 under the push rod of the pusher 44, the movable knife assembly 3 is reset under the action of the pusher 44 to complete a complete thread cutting reciprocating cycle.

[0040] Only the swing rod 41, the thread cutting cam 42 and the pusher 44 are used to realize reciprocating motion, without the need for multiple transmission rods to be cascaded, the components are less, the structure is more stable, after the reduction of parts, the assembly steps are simple, and it is more convenient to troubleshoot and replace parts, the thread cutting cam 42-swing rod 41 structure reduces transmission error and wear points and improves reliability.

[0041] The relationship between the fixed knife 2 and the movable knife assembly 3 is consistent with the structure in the prior art, the movable knife assembly 3 is translated relative to the fixed knife 2 to realize cutting. The present application mainly improves the driving assembly 4 of the movable knife assembly 3 to make the structure more simple.

[0042] As shown in the drawings, Figure 1 In the present application, the sewing machine has a driving motor and transmission rod body, bevel gear pair and the like structure, which is used to drive the rotation of the transmission shaft 43 and cooperate with the needle and rotating hook assembly. The needle and rotating hook assembly is the prior art.

[0043] When the mechanism is installed in the sewing machine, the relative positions among the fixed knife 2, the transmission shaft 43, the first axis of the swing rod 41 and the pusher 44 are kept unchanged. The overall structure is used to drive the activity of the movable knife assembly 3 through the driving assembly 4 to realize thread cutting.

[0044] Therefore, as Figure 1 As shown, it also includes a first fixed component 7 and a second fixed component 8. The swing rod 41 is rotatably connected to the first fixed component 7, and the pusher 44 is fixed to the second fixed component 8.

[0045] Specifically, such as Figures 1 to 3 As shown, it also includes a linear guide rail 6. The moving blade assembly 3 includes a moving blade body 31 and a moving blade holder 32. The moving blade body 31 is fixed on the moving blade holder 32, and the moving blade holder (32) is fixed on the slider 61 of the linear guide rail 6.

[0046] The moving blade holder 32 cooperates with the linear guide rail 6 to ensure that the moving blade assembly 3 moves smoothly during the wire cutting process and will not shift in position.

[0047] Specifically, such as Figure 6 As shown, it also includes a fixed tool holder 5, which has a guide groove 51. The moving tool body 31 is slidably disposed in the guide groove 51 and passes through the guide groove 51.

[0048] The fixed blade holder 5 firmly installs the fixed blade 2, and the guide groove 51 provides a stable movement channel for the moving blade body 31. Since the moving blade has a relatively slender blade body, the guide groove 51 further limits its position, effectively ensuring that the position does not shift during the cutting process. The guide groove 51 and the moving blade body 31 are sized to precisely limit the movement trajectory of the moving blade. With the constraint of the guide groove 51, the vibration generated during cutting can be effectively suppressed, and the cutting accuracy can be improved. The fixed blade 2 and the moving blade body 31 are set up vertically.

[0049] Specifically, such as Figures 1 to 3 as well as Figure 6 As shown, the fixed blade 2 is detachably mounted on the fixed blade holder 5, and the fixed blade 2 at least partially covers the guide groove 51 to restrict the moving blade body 31 from disengaging from the guide groove 51.

[0050] The fixed blade 2 covers the opening of the guide groove 51, which can effectively prevent the moving blade body 31 from detaching from the guide groove 51 due to vibration or reverse force, thus improving the safety of the mechanism. Furthermore, the fixed blade 2 is in contact with the moving blade body 31, which effectively suppresses the vibration of the moving blade during movement. The fixed blade 2 is detachable and can be adjusted by tightening screws, which not only ensures reliable fixation but also allows for easy disassembly and maintenance when needed. In the event of damage to the moving blade body 31, the fixed blade 2 can be directly removed to replace the moving blade body 31.

[0051] Specifically, such as Figure 6 As shown, the fixed tool holder 5 is also provided with a limiting part 52, which is used to restrict the moving tool holder 32 from moving toward the fixed tool 2.

[0052] The limiting part 52 is a limiting recess corresponding to the guide groove 51 on the fixed cutter seat 5, and the limiting recess is in communication with the guide groove 51. The limiting recess allows the partial movable cutter seat 32 to enter the limiting recess, but cannot pass through the limiting recess to enter the guide groove 51. In some special cases, the movable cutter seat 32 is prevented from moving the movable cutter body 31 excessively.

[0053] Specifically, as shown in Figure 5 The swing rod 41 is provided with a guide hole 411, and the movable cutter assembly 3 further comprises a connecting shaft 33 and a guide block 34. The guide hole 411 is arranged along the length direction of the swing rod 41, the guide block 34 is rotatably assembled on the connecting shaft 33, the connecting shaft 33 is installed on the movable cutter seat 32, and the guide block 34 is arranged in the guide hole 411 and can slide in the guide hole 411.

[0054] When the driving assembly 4 swings the swing rod 41 around the first axis, the movable cutter assembly 3 is driven to translate. Since the movable cutter assembly 3 is in a translation state, and the swing rod 41 is in a circular motion, a movable cutter seat 32 capable of sliding along the guide hole of the swing rod 41 is arranged. Then, the connecting shaft 33 on the movable cutter assembly 3 is inserted into the guide block 34 and can rotate relative to the guide block 34. When the swing rod 41 drives the movable cutter assembly 3 to translate, the guide block 34 moves in the guide hole 411, thereby achieving driving.

[0055] The two sides of the guide block 34 are in contact with the inside of the guide hole 411, and the guide block 34 can only move along the length direction of the swing rod 41 towards the guide hole 411.

[0056] The connecting shaft 33 is rotatably connected to or fixed on the movable cutter seat 32, and two limiting blocks for limiting the swing rod 41 are arranged on the connecting shaft 33. The swing rod 41 is arranged between the two limiting blocks. The limiting blocks reduce the possibility of the swing rod 41 being offset up and down.

[0057] Specifically, the pusher 44 is specifically an electromagnetic pusher or a telescopic cylinder. The electromagnetic pusher is a commonly used component on a sewing machine, which will not be described in detail here and is a well-known common sense.

[0058] Specifically, as shown in Figure 5 The contact assembly 45 comprises a rotating ring 451 and a rod body 452. The rod body 452 is arranged on the swing rod 41, and the rotating ring 451 is rotatably arranged on the rod body 452 and in contact with the thread cutting cam 42. The push rod end of the pusher 44 is provided with a connecting block 441, the connecting block 441 is provided with a movable hole 442, and the lower end of the rod body 452 is inserted into the movable hole 442 and can translate in the movable hole 442.

[0059] Further, the rod body 452 is rotatably arranged on or fixed on the swing rod 41, the rod body 452 penetrates through the swing rod 41, the upper end of the rod body 452 is arranged with the rotating ring 451, and the lower end of the rod body 452 is inserted into the movable hole 442, the width of the movable hole 442 is close to the diameter of the rod body 452, and the length of the movable hole 442 is greater than the diameter of the rod body 452, so that the rod body 452 can move in the length direction of the movable hole 442.

[0060] The rotating ring 451 can freely rotate around the rod body 452, the rotating ring 451 is in direct contact with the cutting thread cam 42, the cam motion is accurately transmitted to the swing rod 41 through the rod body 452, the contact abrasion between the cutting thread cam 42 and the rod body 452 is reduced, and the service life is prolonged, the connecting block 441 at the end of the push rod of the pusher 44 is arranged with the movable hole 442, and in the pushing process, the rod body 452 can also translate in the movable hole 442, so as to overcome the displacement deviation brought by the swing rod 41 in the circumferential motion.

[0061] Specifically, as shown in Figure 2 and Figure 4 The cutting thread cam 42 has an acting surface 421, the acting surface 421 is arranged around the transmission shaft 43, the acting surface 421 is in contact with the contact head assembly 45, the acting surface 421 has a plurality of annularly arranged first abutting surfaces 4211 and second abutting surfaces 4212, the two ends of the first abutting surface 4211 are connected with the two ends of the second abutting surface 4212 through two transition surfaces 4213, and the first abutting surface 4211 is closer to the pusher 44 than the second abutting surface 4212.

[0062] The connecting position of the first abutting surface 4211 and the second abutting surface 4212 is provided with the transition surface 4213, which can provide buffering when the cam slides from one plane to another plane, reduce impact and vibration, and improve the smoothness of action. The first abutting surface 4211 is closer to the pusher 44, which means that when the cutting thread cam 42 rotates to this position, the swing rod 41 can be swung towards the pusher 44, and when the second abutting surface 4212 is in contact with the contact head assembly 45, the swing rod 41 can be swung back towards the fixed knife 2 through the pusher 44.

[0063] Further, the cutting thread cam 42 and the transmission shaft 43 are coaxially arranged.

[0064] It should be noted that all directional indications, such as upper, lower, left, right, front, back, and the like, in the embodiments of the utility model are only used to explain the relative position relationship, movement condition and the like between various components in a certain specific posture, as shown in the drawings, and if the specific posture changes, the directional indications also change accordingly.

[0065] In addition, the description of "first", "second" and the like in the present application is only for the purpose of description and cannot be understood as indicating or implying the relative importance of the technical features or implying the number of the technical features indicated. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features. Meanwhile, the meaning of "and / or" appearing in the whole text is that it includes three schemes, for example, "A and / or B" includes A scheme, or B scheme, or A and B schemes are satisfied at the same time. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the realization of the person skilled in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor is it within the protection scope required by the present application.

[0066] The above components are all general standard components or components known to those skilled in the art, and the structure and principle thereof can be known by those skilled in the art through technical manual or through conventional experimental methods.

[0067] The specific embodiments described herein are merely illustrative of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways, but will not deviate from the present application or exceed the scope defined by the appended claims.

Claims

1. A thread trimming mechanism of a sewing machine, characterized by comprising: It comprises: a fixed blade (2); a movable blade assembly (3) which cooperates with the fixed blade (2) and can be translated relative to the fixed blade (2) for realizing line shearing; a driving assembly (4) for driving the movable blade assembly (3) to move back and forth, the driving assembly (4) comprising: a swing lever (41) which can swing around a first axis, one end of the swing lever (41) being movably connected with the movable blade assembly (3), and a contact assembly (45) being further arranged on the swing lever (41); a rotatable transmission shaft (43) on which a line shearing cam (42) is fixed, the line shearing cam (42) being in contact with the contact assembly (45) so as to enable the swing lever (41) to swing towards a direction away from the fixed blade (2); a pusher (44) whose push rod is connected with the lower end of the contact assembly (45), the pusher (44) being used for enabling the swing lever (41) to swing towards the direction of the fixed blade (2).

2. The thread trimming mechanism of the sewing machine according to claim 1, characterized in that, It further comprises a linear guide rail (6), the movable blade assembly (3) comprising a movable blade body (31) and a movable blade seat (32), the movable blade body (31) being fixed on the movable blade seat (32), and the movable blade seat (32) being fixed on a sliding block (61) of the linear guide rail (6).

3. The thread trimming mechanism of a sewing machine according to claim 2, wherein It further comprises a fixed blade seat (5) on which a guide groove (51) is arranged, the movable blade body (31) being slidably arranged in the guide groove (51) and penetrating the guide groove (51).

4. The thread trimming mechanism of the sewing machine according to claim 3, characterized in that, The fixed blade (2) is detachably arranged on the fixed blade seat (5), the fixed blade (2) at least partially covering the guide groove (51) so as to limit the movable blade body (31) from being separated from the guide groove (51).

5. The thread trimming mechanism of a sewing machine according to claim 3 or 4, characterized in that, The fixed blade seat (5) is further provided with a limiting portion (52) for limiting the movable blade seat (32) from moving towards the direction of the fixed blade (2).

6. The thread trimming mechanism of a sewing machine according to claim 2, wherein The swing lever (41) is provided with a guide hole (411) arranged along the length direction of the swing lever (41), the guide block (34) being rotatably assembled on the connecting shaft (33), the connecting shaft (33) being installed on the movable blade seat (32), the guide block (34) being arranged in the guide hole (411) and being slidable in the guide hole (411).

7. The thread trimming mechanism of a sewing machine according to claim 1, wherein The pusher (44) is specifically an electromagnetic pusher (44) or a telescopic cylinder.

8. The thread trimming mechanism of a sewing machine according to claim 1, wherein The contact assembly (45) comprises a rotating ring (451) and a rod body (452), the rod body (452) being arranged on the swing lever (41), the rotating ring (451) being rotatably arranged on the rod body (452) and being in contact with the line shearing cam (42), the push rod end of the pusher (44) being provided with a connecting block (441), the connecting block (441) being provided with a movable hole (442), the lower end of the rod body (452) being inserted into the movable hole (442) and being translatable in the movable hole (442).

9. The thread trimming mechanism of a sewing machine according to claim 1, wherein The cutting line cam (42) has an acting surface (421) arranged around the transmission shaft (43), the acting surface (421) is in contact with the contactor assembly (45), the acting surface (421) has a plurality of annularly arranged first abutting surfaces (4211) and second abutting surfaces (4212), two ends of the first abutting surface (4211) are connected with two ends of the second abutting surface (4212) through two transition surfaces (4213), and the first abutting surface (4211) is closer to the pusher (44) than the second abutting surface (4212).

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