Automatic thread trimming mechanism for zigzag seam

Abstract

The utility model discloses an automatic zigzag seam trimming mechanism which comprises a fixed cutter, a movable cutter, a driving arm and a driving motor, one end of the driving arm is rotationally connected to a rotating shaft, the other end of the driving arm is connected with a sliding block fixing seat, the sliding block fixing seat is clamped on a linear guide rail, the output end of the driving motor is connected with an ejector rod, and the ejector rod abuts against the middle of the driving arm. A fixing plate is installed on the side face of the driving motor, a spring is connected between the sliding block fixing base and the fixing plate, the movable cutter is fixed to the sliding block fixing base, and when the driving arm swings, the movable cutter moves front and back relative to the fixed cutter. A driving arm and a driving motor are arranged, the driving motor controls an ejector rod to eject and press the driving arm to swing, so that a movable cutter arranged at one end of the driving arm moves and forms thread trimming action with a fixed cutter, and power of the driving motor is converted into linear motion of the movable cutter through swing of the driving arm through an indirect transmission structure formed by the driving arm and the ejector rod. And the locked-rotor risk caused by direct stress of the driving motor is avoided.

Description

Technical Field

[0001] This utility model relates to the field of zigzag sewing technology, specifically to an automatic thread-cutting mechanism for zigzag sewing. Background Technology

[0002] Zigzag stitch is a non-straight stitch in sewing technology. Its core feature is that the sewing machine needle swings laterally during the sewing process, forming variable stitches such as Z-shapes and wavy shapes. It is mainly used in the manufacture of thick materials such as shoes, bags, and car seat cushions, and plays the role of splicing and decorative seams in sewing.

[0003] The thread-cutting mechanism is a device in a sewing machine used to automatically cut the top and bottom threads. It belongs to the field of sewing automation technology, and its core function is to replace manual thread cutting to improve efficiency and sewing quality. This mechanism typically consists of a moving blade, a stationary blade, and a drive system. It cuts the thread by the engagement of the blades. Currently, most thread-cutting mechanisms on the market use a linear motor as their drive system. The moving blade is directly mounted on the motor's output end to control its movement. In this drive system, the motor's driving force is directly transmitted to the moving blade. If mechanical interference occurs when the moving blade interacts with other components, causing the structure to jam, it will affect the normal operation of the motor and lead to motor stall. Utility Model Content

[0004] Therefore, in order to solve the above problems, the purpose of this utility model is to provide an automatic thread-cutting mechanism for zigzag seams, comprising:

[0005] Fixed cut;

[0006] The drive arm has one end rotatably connected to a rotating shaft and the other end connected to a slider fixing seat, which is snapped onto a linear guide rail.

[0007] A drive motor is provided, with a push rod connected to its output end. The push rod abuts against the middle of the drive arm. A fixing plate is mounted on the side of the drive motor, and a spring connects the slider fixing seat and the fixing plate.

[0008] The moving blade is fixed to the slider fixing seat and cooperates with the fixed blade.

[0009] The push rod is used to control the swing of the drive arm. When the drive arm swings, the moving tool moves back and forth relative to the fixed tool.

[0010] Preferably, the fixed blade is disposed at the upper end of the fixed blade fixing seat, the middle part of the fixed blade fixing seat is provided with a gap through which the movable blade can pass, and the lower end of the fixed blade fixing seat is provided with a wire clamping plate and an adjusting screw. The adjusting screw is threadedly connected to the fixed blade fixing seat, the adjusting screw abuts against the wire clamping plate, and the wire clamping plate abuts against the movable blade.

[0011] Preferably, the slider fixing seat is provided with a sliding groove, and a sliding block is rotatably connected to the end of the drive arm away from the rotating shaft. The movable block is engaged in the sliding groove and can move along the sliding groove.

[0012] Preferably, the moving direction of the movable block is perpendicular to the setting direction of the linear guide rail.

[0013] Preferably, it includes a drive shaft, on which a wire-cutting cam is fixed, and a cylindrical block is connected to the middle of the drive arm. The cylindrical block cooperates with the wire-cutting cam, and the wire-cutting cam is used to limit the swing angle of the drive arm.

[0014] Preferably, the wire-cutting cam includes a path surface, which includes an exit surface and a retract surface. The exit surface and the retract surface are connected by a transition surface. When the cylindrical block abuts against the exit surface, the moving blade extends out to the maximum distance relative to the fixed blade. When the cylindrical block abuts against the retract surface, the moving blade extends out to the minimum distance relative to the fixed blade.

[0015] Preferably, the front end of the push rod is hemispherical, and the middle part of the drive arm has a protrusion that engages with the push rod.

[0016] The beneficial effects of this utility model are:

[0017] The system includes a drive arm and a drive motor. The drive motor controls the push rod to push the drive arm to swing, causing the moving blade at one end of the drive arm to move and form a shearing action with the fixed blade. Through the indirect transmission structure formed by the drive arm and the push rod, the power of the drive motor is converted into the linear motion of the moving blade through the swing of the drive arm, avoiding the risk of stalling caused by the drive motor being directly subjected to force. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of one side of the structure of this utility model;

[0020] Figure 2 This is a schematic diagram of the other side of the structure of this utility model;

[0021] Figure 3 A schematic diagram of the moving blade, fixed blade, wire clamping plate, and adjusting screw;

[0022] Figure 4 A schematic diagram of the wire-cutting cam and drive arm;

[0023] The following are the symbols and their meanings: 1. Fixed blade; 2. Moving blade; 3. Drive motor; 31. Push rod; 32. Spring; 4. Drive arm; 41. Rotating shaft; 42. Slider; 5. Slider fixing seat; 51. Fixed blade fixing seat; 52. Adjusting screw; 53. Wire clamping plate; 54. Sliding groove; 55. Cylindrical block; 6. Linear guide rail; 7. Drive shaft; 71. Wire cutting cam; 711. Exit face; 712. Retract face; 713. Transition surface; 8. Bevel gear.

[0024] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0026] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] Unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0028] Example 1:

[0029] Figures 1-4This invention provides an automatic thread-cutting mechanism for zigzag seams. This mechanism works in conjunction with a sewing machine to continuously sew zigzag seams on products such as bags and shoes. The thread-cutting mechanism includes a fixed blade 1, a moving blade 2, a drive arm 4, and a drive motor 3. One end of the drive arm 4 is rotatably connected to a rotating shaft 41, and the other end is connected to a slider fixing seat 5, which is engaged with a linear guide rail 6. The output end of the drive motor 3 is connected to a push rod 31, which abuts against the middle of the drive arm 4. A fixing plate is mounted on the side of the drive motor 3. A spring 32 connects the slider fixing seat 5 to the fixing plate. The moving blade 2 is fixed to the slider fixing seat 5. The moving blade 2, in conjunction with the fixed blade 1, can perform thread-cutting actions. The push rod 31 controls the swing of the drive arm 4. When the drive arm 4 swings, the moving blade 2 moves back and forth relative to the fixed blade 1.

[0030] The front end of the push rod 31 is hemispherical, and the middle part of the drive arm 4 has a protrusion. The protrusion cooperates with the push rod 31. The drive motor 3 controls the push rod 31 to extend and abut against the protrusion. The protrusion swings together with the drive arm 4. The spring 32 is used to reset the drive arm 4.

[0031] It should be noted that the four components, namely the rotating shaft 41, the linear guide rail 6, the drive motor 3, and the fixed blade 1, are relatively fixed in position and can be fixed together on the frame of the sewing equipment.

[0032] A fixed blade 1 is positioned at the upper end of a fixed blade fixing seat 51. The fixed blade fixing seat 51 has a gap in its middle for the moving blade 2 to pass through. The lower end of the fixed blade fixing seat 51 has a wire clamping plate 53 and an adjusting screw 52. The adjusting screw 52 is threadedly connected to the fixed blade fixing seat 51 and abuts against the wire clamping plate 53. The wire clamping plate 53 abuts against the moving blade 2. The wire clamping plate 53 has a certain degree of toughness and can undergo elastic deformation within a controllable range. The adjusting screw 52 is positioned in a pre-set screw hole in the fixed blade fixing seat 51 and can rotate within the screw hole through threaded engagement to adjust its position. Under normal conditions, the adjusting screw 52 abuts against and applies a certain pressure to the wire clamping plate 53, causing it to slightly adhere to the moving blade 2, thus achieving the wire clamping function. When it is necessary to adjust the wire clamping pressure, the adjusting screw 52 can be turned to move it closer to / away from the moving blade 2, thereby increasing / decreasing the pushing force on the wire clamping plate 53 and thus changing the wire clamping pressure. Figure 3 The area marked in black is the end of the adjusting screw 52 that directly contacts the clamping piece 53.

[0033] Since the drive arm 4 rotates and swings along the pivot 41, the movement trajectory of the parts fixed on the drive arm 4 is arc-shaped, which does not meet the linear movement trajectory requirement of the moving blade 2. Therefore, specific structural restrictions need to be imposed on this part. In this embodiment, a slider 42 and a sliding groove 54 are used to convert the swinging motion of the drive arm 4 into the linear driving force of the moving blade 2. Specifically, the slider fixing seat 5 is provided with a sliding groove 54, and a sliding block is rotatably connected to the end of the drive arm 4 away from the pivot 41. The movable block is engaged in the sliding groove 54 and can move along the sliding groove 54. The moving direction of the movable block is perpendicular to the setting direction of the linear guide rail 6. After this setting, the slider fixing seat 5 and the moving blade 2 only move linearly along the linear guide rail 6. The swinging motion of the drive arm 4 along the pivot 41 radially is converted into the driving force for the slider 42 to move in the sliding groove 54, which will not interfere with the normal linear movement of the moving blade 2.

[0034] An additional drive shaft 7 is added, and a thread-cutting cam 71 is fixedly mounted on the drive shaft 7. A cylindrical block 55 is connected to the middle of the drive arm 4. The cylindrical block 55 cooperates with the thread-cutting cam 71. The thread-cutting cam 71 is used to limit the swing angle of the drive arm 4. The thread-cutting cam 71 includes a path surface, which includes an exit surface 711 and a retract surface 712. The exit surface 711 and the retract surface 712 are connected by a transition surface 713. When the cylindrical block 55 abuts against the exit surface 711, the moving blade 2 extends to the maximum distance relative to the fixed blade 1. When the cylindrical block 55 abuts against the retract surface 712, the moving blade 2 extends to the minimum distance relative to the fixed blade 1. By cooperating with the cylindrical block 55, the swing of the drive arm 4 is limited, thereby controlling the movement of the moving blade 2. This ensures that the thread-cutting action of the thread-cutting mechanism and the sewing action of the sewing machine are coordinated to continuously produce zigzag seams.

[0035] Drive shaft 7, via bevel gear 8 at one end, works in conjunction with other components of the sewing machine to optimize the timing of sewing and thread-cutting actions. (See details...) Figure 4 .

[0036] It should also be noted that the spring 32 in the attached figure is for illustration only and does not represent the actual connection. In reality, the two ends of the spring 32 are connected to the slider fixing seat 5 and the fixing plate respectively, which can provide elastic force to make the drive arm 4 return to its original position.

[0037] Working principle:

[0038] After the drive motor 3 starts, the hemispherical push rod 31 at its output end extends forward and presses against the protrusion in the middle of the drive arm 4, forcing the drive arm 4 to swing clockwise around the rotating shaft 41. The end of the drive arm 4 away from the rotating shaft 41 cooperates with the sliding groove 54 of the slider fixing seat 5 through the sliding block, pushing the slider fixing seat 5 to make a precise linear movement along the linear guide rail 6, driving the moving blade 2 to extend towards the fixed blade 1 to complete the thread cutting. After the thread cutting is completed, the drive motor 3 retracts the push rod 31, and the drive arm 4 resets counterclockwise under the tension of the spring 32, and the moving blade 2 synchronously returns to its initial position. The thread cutting cam 71 contacts the cylindrical block 55 on the drive arm 4 through the path curved surface (the blade exit surface 711 and the blade retraction surface 712), limiting the maximum swing angle of the drive arm 4, ensuring that the stroke of the moving blade 2 is synchronized with the swing of the sewing machine needle bar, and avoiding interference with the tortuous sewing stitch when cutting the thread. The thread clamping plate 53 fixes the thread end by adjusting the pre-tightening force of the adjusting screw 52, ​​realizing the reliability and continuity of the thread cutting action in the sewing of thick materials.

[0039] The above description is only an optional embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. An automatic thread-cutting mechanism for zigzag seams, characterized in that, include: Fixed blade (1); Drive arm (4), one end of which is rotatably connected to the rotating shaft (41), and the other end is connected to a slider fixing seat (5), which is snapped onto the linear guide rail (6); A drive motor (3) is provided, and a push rod (31) is connected to the output end of the drive motor (3). The push rod (31) abuts against the middle of the drive arm (4). A fixing plate is installed on the side of the drive motor (3). A spring (32) is connected between the slider fixing seat (5) and the fixing plate. The moving blade (2) is fixed to the slider fixing seat (5) and cooperates with the fixed blade (1); The push rod (31) is used to control the swing of the drive arm (4). When the drive arm (4) swings, the moving blade (2) moves back and forth relative to the fixed blade (1).

2. The automatic thread-cutting mechanism for zigzag seams according to claim 1, characterized in that, The fixed blade (1) is set at the upper end of the fixed blade fixing seat. The middle part of the fixed blade fixing seat (51) is provided with a gap through which the movable blade (2) can pass. The lower end of the fixed blade fixing seat (51) is provided with a wire clamping plate (53) and an adjusting screw (52). The adjusting screw (52) is threaded to the fixed blade fixing seat (51). The adjusting screw (52) abuts against the wire clamping plate (53). The wire clamping plate (53) abuts against the movable blade (2).

3. The automatic thread-cutting mechanism for zigzag seams according to claim 1, characterized in that, The slider fixing seat (5) is provided with a sliding groove (54). The end of the drive arm (4) away from the rotating shaft (41) is rotatably connected to a sliding block. The movable block is engaged in the sliding groove (54) and can move along the sliding groove (54).

4. The automatic thread-cutting mechanism for zigzag seams according to claim 3, characterized in that, The moving direction of the movable block is perpendicular to the setting direction of the linear guide rail (6).

5. The automatic thread-cutting mechanism for zigzag seams according to claim 1, characterized in that, Includes a drive shaft (7), on which a wire-cutting cam (71) is fixed, and a cylindrical block (55) is connected in the middle of the drive arm (4). The cylindrical block (55) cooperates with the wire-cutting cam (71), and the wire-cutting cam (71) is used to limit the swing angle of the drive arm (4).

6. The automatic thread-cutting mechanism for zigzag seams according to claim 5, characterized in that, The shearing cam (71) includes a path surface, which includes an exit surface (711) and a retract surface (712). The exit surface (711) and the retract surface (712) are connected by a transition surface (713). When the cylindrical block (55) abuts against the exit surface (711), the moving blade (2) extends out to the maximum distance relative to the fixed blade (1). When the cylindrical block (55) abuts against the retract surface (712), the moving blade (2) extends out to the minimum distance relative to the fixed blade (1).

7. The automatic thread-cutting mechanism for zigzag seams according to claim 1, characterized in that, The front end of the push rod (31) is hemispherical, and the middle part of the drive arm (4) has a protrusion that cooperates with the push rod (31).

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