Flat bed sewing machine and its thread winding device

Abstract

The application discloses a flat sewing machine and belongs to the technical field of sewing machines. The flat sewing machine comprises a rack, a main shaft and a lower shaft are arranged in the rack, and the main shaft and the lower shaft are connected through a synchronous belt. One end of the main shaft is provided with a main motor, and the main motor is used for driving the main shaft to rotate. The main shaft and the lower shaft are connected through the synchronous belt, so that the rotation of the main shaft can be transmitted to the lower shaft. The transmission structure is very simple, the space occupied is small, other functional components can be accommodated, and combination with other functional components can be realized.

Description

[0001] This application is 2020110678897, a divisional application for a flat sewing machine. Technical Field

[0002] This invention belongs to the field of sewing machine technology, and specifically refers to a flat sewing machine. Background Technology

[0003] Currently, existing flatbed sewing machines typically use a motor to drive the rotation of the main shaft, and then transmit the power to the lower shaft, fabric feed shaft, and feed dog shaft through a series of linkage mechanisms.

[0004] However, as can be seen from the above structure, it is still quite complex, especially since existing flatbed sewing machines often require the addition of many extra functions. The purely mechanical structure suffers from large space requirements, complex structure, and difficulty in coordinating with other functional components. Summary of the Invention

[0005] The purpose of this invention is to provide a flat sewing machine that connects the main shaft and the lower shaft via a synchronous belt, thereby enabling the power of the main motor to be transmitted to the lower shaft.

[0006] The objective of this invention is achieved as follows: a flat sewing machine includes a frame, in which a main shaft and a lower shaft are arranged, and the main shaft and the lower shaft are connected by a synchronous belt; a main motor is arranged at one end of the main shaft, and the main motor is used to drive the main shaft to rotate.

[0007] Preferably, it further includes an inner pressure foot assembly and an outer pressure foot assembly. The upper ends of the inner and outer pressure foot assemblies are provided with an interaction adjustment device for the inner and outer pressure feet. The interaction adjustment device includes a pressure foot interaction mechanism, which drives the alternating lifting and lowering of the inner and outer pressure foot assemblies; a swing crank mechanism, which provides a reciprocating swing force to the pressure foot interaction mechanism; a pressure foot lifting crank mechanism, which converts the rotational motion of the main shaft into the reciprocating swing required by the swing crank mechanism; and a swing amount adjustment mechanism, which adjusts the amplitude of the reciprocating swing converted by the pressure foot lifting crank mechanism.

[0008] Preferably, the swing adjustment mechanism includes a drive motor, an eccentric wheel is mounted on the motor shaft of the drive motor; a swing member abuts against the wheel surface of the eccentric wheel, a transmission shaft is fixedly provided on the other side of the swing member, and the other end of the transmission shaft is fixedly connected to the swing seat of the presser foot lifting crank mechanism.

[0009] Preferably, a strip groove is provided on the side of the swing member near the motor shaft, the eccentric wheel is disposed in the strip groove, and the upper and lower sidewalls of the strip groove abut against the upper and lower sides of the eccentric wheel simultaneously; the transmission shaft and the main shaft are arranged in parallel.

[0010] Preferably, the presser foot interaction mechanism includes a lifting seat, a lifting bracket, an inner presser foot assembly, and an outer presser foot assembly; the lifting seat is disposed on the lifting bracket, and an outer presser foot rod is disposed on the rear side of the lower part of the lifting seat, and an inner presser foot rod is disposed on the front side of the lower part of the lifting seat; the rear side of the lower part of the lifting seat, the lifting bracket, and the upper end of the outer presser foot rod are coaxially hinged; the front side of the lower part of the lifting seat is hinged to the upper end of the inner presser foot rod.

[0011] Preferably, the swing crank mechanism includes an intermediate shaft, and a swing crank is fitted in the middle of the intermediate shaft; a lifting crank is installed at one end of the intermediate shaft that extends toward the presser foot interaction mechanism; the lifting crank drives the rotation of the lifting seat through a push-pull rod.

[0012] Preferably, the presser foot lifting crank mechanism includes a swing seat with a first support arm and a second support arm respectively disposed on both sides; between the first support arm and the second support arm, a first limiting link, a first transmission link, the output end of the main shaft crank, the input end of the swing crank, a second transmission link, and a second limiting link are sequentially disposed; the front end of the first support arm is hinged to the front end of the first limiting link, the front end of the second support arm is hinged to the front end of the second limiting link, and the rear ends of the first limiting link, the second limiting link, the first transmission link, the second transmission link, and the output end of the main shaft crank are all coaxially hinged; the input end of the swing crank, the front end of the first transmission link, and the front end of the second transmission link are all coaxially hinged; the output end of the main shaft crank and the input end of the swing crank are both disposed between the first transmission link and the second transmission link.

[0013] Preferably, the main shaft is provided with a swing reversing mechanism and a reverse-forward sewing drive motor; the swing reversing mechanism is used to convert the rotational motion of the main shaft into the reciprocating swing required by the fabric feeding shaft; the reverse-forward sewing drive motor has its presser foot motor shaft driving the swing reversing mechanism through a crank assembly, and the swing reversing mechanism swings and adjusts around the reverse-forward sewing intermediate shaft.

[0014] Preferably, the crank assembly includes an eccentric wheel and an eccentric connecting rod. The eccentric wheel is mounted on the motor shaft, one end of the eccentric connecting rod is fitted onto the eccentric wheel, and the other end of the eccentric connecting rod is hinged to a rocker arm. The other end of the rocker arm is fixed to the intermediate shaft of the forward and reverse joint.

[0015] Preferably, the swing reversing mechanism includes a swing seat, on both sides of which a first swing support arm and a second swing support arm are respectively provided; between the first swing support arm and the second swing support arm, a first swing limiting link, a first swing transmission link, the output end of the main shaft crank, the input end of the swing crank, a second transmission link, and a second limiting link are sequentially provided.

[0016] The front end of the first swing support arm is hinged to the front end of the first swing limiting link, and the front end of the second swing support arm is hinged to the front end of the second limiting link. The rear ends of the first swing limiting link, the rear ends of the second limiting link, the rear ends of the first swing transmission link, the rear ends of the second transmission link, and the output end of the main shaft crank are all coaxially hinged. The input end of the swing crank, the front end of the first swing transmission link, and the front end of the second transmission link are all coaxially hinged. The output end of the main shaft crank and the input end of the swing crank are both located between the first swing transmission link and the second transmission link. A horizontal tie rod is hinged to the lower end of the swing crank, and a rotating crank is hinged to the other end of the horizontal tie rod. A feed shaft is sleeved inside the rotating crank.

[0017] Preferably, the device further includes a presser foot lifting device, which includes a presser foot lifting bracket assembly installed at the head of the frame of the sewing machine; a lifting shaft assembly installed inside the crossbeam of the frame for lifting or lowering the presser foot lifting bracket assembly; a presser foot lifting motor installed on the frame for driving the lifting shaft assembly; a rotating disk installed on the presser foot motor shaft of the presser foot lifting motor; the rotating disk is provided with a curved travel section, the curvature of the contour line of the curved travel section gradually increases; a linkage crank, one end of which is fixedly installed on the presser foot lifting shaft of the lifting shaft assembly, and the other end is equipped with a driven pin; the driven pin is pressed against the curved travel section.

[0018] Preferably, the curved travel portion is an inner groove formed on the rotating disk, or the curved travel portion is the outer contour of the rotating disk; at least a portion of the contour curve of the curved travel portion is a spiral line centered on the axis of the presser foot motor shaft; a swing arm torsion spring is sleeved on the presser foot lifting shaft, the swing arm torsion spring including a first pressure rod and a second pressure rod, the first pressure rod abutting against the inner sidewall of the frame; the second pressure rod is disposed on the presser foot lifting shaft and rotates synchronously with the presser foot lifting shaft; a lifting swing arm is sleeved on the presser foot lifting shaft, the lifting swing arm rotating synchronously with the presser foot lifting shaft; the second pressure rod abutting against the upper end face of the lifting swing arm; the lifting swing arm includes a pressure roller portion and a limiting portion, the pressure roller portion being disposed on the rotating convex... Between the wheel and the second pressure rod; the second pressure rod is disposed between the pressure wheel and the limiting part; a pressure foot wrench is also disposed on the outside of the frame, one end of the pressure foot wrench is connected to a wrench shaft, the outer end of the wrench shaft is fitted with a rotating cam, the outer edge of the rotating cam abuts against a lifting and pressing swing arm; the end face of the rotating cam is formed with several mounting holes, which are used to connect with the wrench shaft, and the wrench shaft drives the pressure foot lifting shaft to rotate at different arcs by connecting with different mounting holes; one end of the pressure foot wrench is formed with a connecting shaft, and the wrench shaft is fitted inside the connecting shaft; a wrench torsion spring is fitted outside the connecting shaft, and the wrench torsion spring includes a third pressure rod and a fourth pressure rod, the third pressure rod passing through the pressure foot wrench; the fourth pressure rod passing through the frame;

[0019] One end of the presser foot lifting shaft is fitted with a lifting swing arm, which rotates synchronously with the presser foot lifting shaft; the presser foot lifting bracket assembly includes a lifting frame, and the lower end of the lifting frame is connected to a presser foot rod; one side of the lifting frame extends to form an abutment portion, and the lifting swing arm abuts against the lower end face of the abutment portion.

[0020] Preferably, the device further includes a winding device, which includes a tensioning wheel assembly disposed within the frame. The tensioning wheel assembly has a roller portion that abuts against the synchronous belt and rotates accordingly. A friction surface is provided on the front side of the roller portion. A winding mechanism is also disposed at the front of the housing, with the winding shaft of the winding mechanism extending into the frame and fitted with a friction wheel. The winding mechanism has a working state and a non-working state: when the winding mechanism is in the working state, the friction wheel abuts against the friction surface and is driven; when the winding mechanism is in the non-working state, the friction wheel disengages from the friction surface. One end of the roller portion is connected to an adjusting shaft, and the adjusting shaft rotates synchronously with the roller portion. The adjusting shaft is eccentrically positioned relative to the roller portion, and the adjusting shaft is used to drive the roller portion to rotate eccentrically by its own rotation, thereby adjusting the tension. One end of the adjusting shaft has a connecting hole, in which a connecting shaft is disposed. The connecting shaft passes sequentially through the roller portion and the adjusting shaft, and is connected to the adjusting shaft through the connecting hole.

[0021] The outstanding and beneficial technical effects of this invention compared to the prior art are:

[0022] 1. This invention utilizes a synchronous belt to connect the main shaft and the lower shaft, thereby transmitting the rotation of the main shaft to the lower shaft. The transmission structure is very simple, occupies little space, can accommodate other functional components, and can also be combined with other functional components. Attached Figure Description

[0023] Figure 1 This is a simplified structural diagram of the flat sewing machine of the present invention; Figure 2 It is an enlarged view of the presser foot wrench and related components; Figure 3 It is an enlarged view of the lifting and pressing swing arm and related components; Figure 4 This is one of the simplified structural diagrams of the foot lifting device of the present invention; Figure 5 This is the second simplified structural diagram of the foot lifting device of the present invention; Figure 6 This is the third simplified structural diagram of the foot lifting device of the present invention; Figure 7 This is a schematic diagram of the rotating disk;

[0024] Figure 8 This is one of the simplified structural diagrams of the interaction adjustment device for the inner and outer pressure feet; Figure 9 This is the second simplified structural diagram of the interactive adjustment device for the inner and outer pressure feet; Figure 10 This is a simplified structural diagram of the presser foot interaction mechanism; Figure 11This is one of the simplified structural diagrams of the presser foot lifting crank mechanism; Figure 12 This is the second simplified structural diagram of the presser foot lifting crank mechanism; Figure 13 This is one of the schematic diagrams of the presser foot lifting crank mechanism; Figure 14 This is the second schematic diagram of the presser foot lifting crank mechanism;

[0025] Figure 15 This is a simplified structural diagram of Embodiment 2; Figure 16 yes Figure 15 A simplified structural diagram concealing components such as the forward and reverse stitching drive motor; Figure 17 This is a simplified structural diagram of the swing reversing mechanism; Figure 18 This is an exploded view of the oscillating reversing mechanism; Figure 19 It is one of the schematic diagrams illustrating the switching between forward and reverse stitching; Figure 20 This is the second diagram illustrating the principle of switching between forward and reverse stitching;

[0026] Figure 21 This is one of the simplified structural diagrams of Embodiment 4; Figure 22 This is the second simplified structural diagram of Embodiment 4; Figure 23 This is a schematic diagram illustrating the working principle of the winding mechanism and tensioner assembly; Figure 24 yes Figure 22 A partial enlarged view of the winding mechanism and tensioner assembly; Figure 25 This is an exploded view of the tensioner assembly.

[0027] In the diagram: 1-Drive motor; 2-Eccentric wheel; 3-Oscillating component; 4-Main shaft; 5-Lower shaft; 6-Synchronous belt; 7-Intermediate shaft; 8-Lifting crank; 9-Lifting bracket; 10-Lifting seat; 11-Outer pressure foot assembly; 12-Inner pressure foot assembly; 13-Push-pull rod; 14-Pin shaft; 15-Connecting shaft; 16-Motor shaft; 17-Transmission shaft; 18-First hinge shaft; 19-Second hinge shaft; 20-Third hinge shaft; 23-Shaft; 24-Shaft; 25-Connecting shaft; 26-Mounting bracket; 27-Upper shaft hole; 28-Lower shaft hole; 31-Slot; 51-Oscillating seat; 52-First support arm; 53-First limiting link; 54-First transmission link; 55-Oscillating crank; 56-Second limiting link; 57 - Second support arm; 58- Second transmission link; 97- Main motor; 98- Base; 99- Frame; 100- Crank assembly; 101- Presser foot lifting shaft; 102- Feed shaft; 103- Forward and reverse sewing drive motor; 104- Main shaft crank; 105- Forward and reverse sewing swing crank; 106- Rotating crank; 107- Horizontal tie rod; 108- Eccentric link; 109- Swing arm; 110- Forward and reverse sewing motor shaft; 111- Forward and reverse sewing eccentric wheel; 112- Forward and reverse sewing intermediate shaft; 113- Output end of main shaft crank; 114- Input end of swing crank; 200- Swing reversing mechanism; 216- Swing seat; 217- Second swing support arm; 218- Second swing limit link; 219- Second swing transmission link; 2 20-First swing transmission link; 221-First swing support arm; 222-First swing limit link; 400-Swing amount adjustment mechanism; 500-Pressure foot lifting crank mechanism; 560-Main shaft lifting crank; 600-Pressure foot interaction mechanism; 700-Swing crank mechanism; 61-Wrench shaft; 62-Connecting shaft; 63-Wrench torsion spring; 64-Third pressure rod; 65-Fourth pressure rod; 71-Mounting hole; 81-Pressure roller; 82-Limiting part; 801-Pressure foot lifting bracket assembly; 802-Pressure foot rod; 803-Lifting swing arm; 804-Lifting shaft assembly; 805-Pressure foot wrench; 806-Rotating cam; 807-Lifting and pressing swing arm; 808-Linkage crank; 809-Rotating disk; 810-Pressure foot 811-Lifting motor; 812-Curved stroke section; 813-Pressure foot motor shaft; 814-Driven pin shaft; 815-Helix; 816-Lifting frame; 817-Abutting part; 818-Pressure foot lifting shaft; 819-Swing arm torsion spring; 820-Second pressure rod; 821-Wrench shaft; 901-Winding mechanism; 902-Tensioner assembly; 903-Upper synchronous pulley; 904-Friction wheel; 905-Winding base; 906-Lower synchronous pulley; 907-Winding shaft; 908-Bobbin; 909-Support base; 910-Actuating wrench; 911-Roller section; 912-Friction surface; 913-Connecting shaft; 914-Adjusting shaft; 915-Connecting hole; 916-Connecting bearing; 917-Assisting hole. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments.

[0029] Example 1: As Figure 8-14 As shown, a flatbed sewing machine includes a frame 99, within which a main shaft 4 and a lower shaft 10 are arranged, connected by a synchronous belt 6. A main motor 97 is mounted at one end of the main shaft 4, driving its rotation. The flatbed sewing machine also includes an inner presser foot assembly 12 and an outer presser foot assembly 11, with an interaction adjustment device for the inner and outer presser feet located at their upper ends. The interaction adjustment device includes a presser foot interaction mechanism 600, which drives the alternating lifting and lowering of the inner and outer presser foot assemblies 12 and 11; a swing crank mechanism 700, which provides a reciprocating swing force to the presser foot interaction mechanism 600; a presser foot lifting crank mechanism 500, which converts the rotational motion of the main shaft 4 into the reciprocating swing required by the swing crank mechanism 700; and a swing amount adjustment mechanism 400, which adjusts the amplitude of the reciprocating swing converted by the presser foot lifting crank mechanism 500. In this embodiment, the swing amount adjustment mechanism 400 adjusts the rotation amplitude of the presser foot lifting crank mechanism 500, which in turn adjusts the interaction amount between the inner presser foot assembly 12 and the outer presser foot assembly 11 through the swing crank mechanism 700 and finally through the presser foot interaction mechanism 600.

[0030] The following is a detailed description of the structure of the swing adjustment mechanism 400. For example... Figure 10 As shown, the swing adjustment mechanism 400 includes a drive motor 1, and an eccentric wheel 2 is mounted on the motor shaft 16 of the drive motor 1; a swing member 3 abuts against the wheel surface of the eccentric wheel 2; in this embodiment, the swing member 3 is generally shaped like a tooth fork, and the eccentric wheel 2 is disposed in the tooth fork.

[0031] Furthermore, a strip groove 31 is provided on the side of the swing member 3 near the motor shaft, and the eccentric wheel 2 is disposed within the strip groove 31, with the upper and lower sidewalls of the strip groove 31 simultaneously abutting against the upper and lower sides of the eccentric wheel; as shown Figure 10 As shown, a drive shaft 17 is fixedly mounted on the other side of the swing member 3, and the drive shaft 17 is arranged parallel to the main shaft 4. This design allows the drive shaft 17 to rotate through a corresponding angle even when the drive motor 1 rotates by a small angle.

[0032] Moreover, in this embodiment, the drive motor 1 is preferably a stepper motor, which, combined with the electronic control system, allows for more precise control. This precision is not only in adjusting the magnitude of the interaction but also in the precision of the adjustment timing, allowing for automatic adjustment by controlling the start and stop of the motor according to actual conditions. The other end of the drive shaft 17 is fixedly connected to the swing seat 51 of the presser foot lifting crank mechanism 500. Thus, when the drive motor 1 rotates at a certain angle, it will drive the eccentric wheel 2 to rotate, and then the swing member 3 will also swing. Since the drive shaft 17 is the swing center of the swing member 3, the swing of the swing member 3 will be converted into the rotation of the drive shaft 17, and then the swing seat 51 will also swing. In this embodiment, one end of the drive shaft 17 extends into the swing seat 51, and then fasteners pass through the swing seat 51 and abut against the end of the drive shaft 17 to achieve linkage between the two. The other end is set in the same way. Next, the structural design of the swing seat 51 after swinging will be described in detail. Preferably, the presser foot lifting crank mechanism 500 includes a swing seat 51, on which a first support arm 52 and a second support arm 57 are respectively provided on both sides; as Figure 11 As shown, the aforementioned swing seat 51 has two sides along its length. Furthermore, in this embodiment, both the first support arm 52 and the second support arm 57 are integrally formed with the swing seat 51, thereby increasing the strength of the swing seat 51. Between the first support arm 52 and the second support arm 57, a first limiting link 53, a first transmission link 54, the output end of the main shaft lifting crank 560, the input end of the swing crank 55, a second transmission link 58, and a second limiting link 56 are sequentially arranged; the input end of the swing crank 55, the front end of the first transmission link 54, and the front end of the second transmission link 58 are all coaxially hinged; the front end of the first support arm 52 is hinged to the front end of the first limiting link 53, and this hinge is achieved by having a shaft pass through both the front end of the first support arm 52 and the front end of the first limiting link 53. Figure 11 As shown, this axis is the first hinge axis 18.

[0033] The front end of the second support arm 57 is hinged to the front end of the second limiting link 56. This hinge is also achieved coaxially. Figure 11 As shown, this shaft is also the first hinge shaft 18. The rear ends of the first limiting link 53, the second limiting link 56, the first transmission link 54, the second transmission link 58, and the output end of the main shaft lifting crank 560 are all coaxially hinged, and this shaft is the third hinge shaft 20; the output end of the main shaft lifting crank 560 and the input end of the swing crank 55 are both located between the first transmission link 54 and the second transmission link 58. The output end of the main shaft lifting crank 560 rotates synchronously with the third hinge shaft 20 through fasteners. Specifically, as... Figure 11 and Figure 12As shown, the output end of the main shaft lifting crank 560, the rear end of the first transmission link 54, and the rear end of the second transmission link 58 are coaxially hinged through the third hinge shaft 20; the front end of the first transmission link 54, the front end of the second transmission link 58, and the input end of the swing crank 55 are coaxially hinged through the second hinge shaft 19.

[0034] In this embodiment, through the aforementioned series of transmission processes, the initial angle of the swing seat 51 is adjusted to change the interaction amount, thereby adjusting the interaction amount. Specifically, the drive motor 1 rotates, causing the swing seat 51 to swing. Then, the first limiting link 53 and the second limiting link 56 swing. Subsequently, the sewing machine spindle rotates, causing the output end of the spindle lifting crank 560 to rotate. Because the output end of the spindle lifting crank 560 reciprocates due to eccentricity, and because both the output end of the spindle lifting crank 560 and the input end of the swing crank 55 are located between the first transmission link 54 and the second transmission link 58, the relative distance between the input end of the swing crank 55 and the output end of the spindle lifting crank 560 is fixed. Similarly, the relative distances between the front ends of the first support arm 52 and the second support arm 57 and the output end of the spindle lifting crank 560 are also fixed.

[0035] Therefore, as Figure 13 As shown, with the first hinge shaft 18 stationary as the center, the third hinge shaft 20 rotates around it, corresponding to the second hinge shaft 19 making left and right reciprocating movements. This drives the oscillation of the input end of the oscillating crank 55, thereby driving the intermediate shaft 7 to rotate, and consequently causing the inner and outer pressure feet to oscillate. Therefore, by rotating the drive motor 1 to different positions, the initial positions of the first support arm 52 and the second support arm 57 are changed, which in turn changes the initial position of the first hinge shaft 18. Because the stroke of the second hinge shaft 19 is changed, the interaction between the inner and outer pressure feet is ultimately adjusted.

[0036] Preferably, such as Figure 13 As shown, the swing crank mechanism 700 includes an intermediate shaft 7, with a swing crank 55 mounted on the middle of the intermediate shaft 7; a lifting crank 8 is installed at the end of the intermediate shaft 7 extending towards the presser foot interaction mechanism 600; the lifting crank 8 drives the rotation of the lifting seat 10 via a push-pull rod 13. In this embodiment, the intermediate shaft 7 is clamped by fasteners passing through the upper and lower openings of the crank on the swing crank 55, thereby converting the rotation of the swing crank 55 into the rotation of the intermediate shaft 7, and subsequently the lifting crank 8 will also swing, ultimately achieving the rotation of the lifting seat 10 via the push-pull rod 13.

[0037] The structural design of the presser foot interaction mechanism 600 will be described in detail below. For example... Figure 10As shown, preferably, the presser foot interaction mechanism 600 includes a lifting seat 10, a lifting bracket 9, an inner presser foot assembly 12, and an outer presser foot assembly 11; as Figure 9 As shown, the lifting seat 10 is mounted on the lifting bracket 9, and an outer pressure foot rod 11 is provided on the rear side of the lower part of the lifting seat 10, while an inner pressure foot rod 12 is provided on the front side of the lower part of the lifting seat 10. The rear side of the lower part of the lifting seat 10, the lifting bracket 9, and the upper end of the outer pressure foot rod 11 are coaxially hinged together. The front side of the lower part of the lifting seat 10 is hinged to the upper end of the inner pressure foot rod 12. Thus, the inner pressure foot assembly 12 and the outer pressure foot assembly 11 can be alternately lifted and lowered by the action of the lifting bracket 9, thereby achieving a three-synchronization function. In this embodiment, the lifting seat 10 is triangular in shape, with its upper end hinged to the push-pull rod 13 via a pin 14, and its lower end hinged to the outer pressure foot rod 11 on both sides via connecting shafts 15, and the inner pressure foot rod 12 is similarly hinged to the other side. Figure 10 As shown, when the push-pull rod 13 is pulled to the left, the outer pressure foot rod 11 descends and the inner pressure foot rod 12 rises; conversely, when the push-pull rod 13 is pushed to the right, the outer pressure foot rod 11 rises and the inner pressure foot rod 12 descends. Thus, alternating movements create a three-synchronous design.

[0038] Example 2: Figure 15-20 As shown, a flat sewing machine further includes a feed shaft 102 and a presser foot lifting shaft 101. In the flat sewing machine, the forward and reverse rotation of the feed shaft 102 realizes the forward and reverse sewing. The forward and reverse sewing adjustment device in this embodiment will be described in detail below. The forward and reverse sewing adjustment device includes a swing reversing mechanism 200, which is used to convert the rotational motion of the main shaft 4 into the reciprocating swing required by the feed shaft 102; a forward and reverse sewing drive motor 103, whose forward and reverse sewing motor shaft 110 drives the swing reversing mechanism 200 through a crank assembly 100, and the swing reversing mechanism 200 swings and adjusts around the forward and reverse sewing intermediate shaft 112.

[0039] The structural design of the crank assembly 100 is described in detail below. Preferably, the crank assembly 100 includes: a reverse-coil eccentric wheel 111 and an eccentric connecting rod 108. The reverse-coil eccentric wheel 111 is mounted on the motor shaft. One end of the eccentric connecting rod 108 is fitted onto the reverse-coil eccentric wheel 111, and the other end of the eccentric connecting rod 108 is hinged to a swing arm 109. The other end of the swing arm 109 is fixed to the reverse-coil intermediate shaft 112. The reverse-coil eccentric wheel 111 being mounted on the motor shaft and the eccentric connecting rod 108 being fitted onto the reverse-coil eccentric wheel 111 allows the swing arm 109 to reciprocate, thereby allowing the reverse-coil intermediate shaft 112 to reciprocate. By allowing the reverse-coil intermediate shaft 112 to reciprocate, the amplitude of the swing reversing mechanism 200 can be adjusted, thereby adjusting the amplitude of the reciprocating swing of the fabric feed shaft 102.

[0040] Preferably, the swing reversing mechanism 200 includes a swing base 216, on both sides of which a first swing support arm 221 and a second swing support arm 217 are respectively provided; between the first swing support arm 221 and the second swing support arm 217, a first swing limiting link 222, a first swing transmission link 220, an output end 113 of the main shaft crank, an input end 114 of the swing crank, a second swing transmission link 219, and a second swing limiting link 218 are sequentially arranged; the front end of the first swing support arm 221 is hinged to the front end of the first swing limiting link 222, and the second swing support arm 217... The front end is hinged to the front end of the second swing limiting link 218. The rear ends of the first swing limiting link 222, the second swing limiting link 218, the first swing transmission link 220, the second transmission link 18, and the output end 31 of the main shaft crank 104 are all hinged coaxially 24. The input end of the reverse-forward swaying crank 105, the front end of the first swing transmission link 220, and the front end of the second swing transmission link 219 are all hinged coaxially 23. The output end 113 of the main shaft crank and the input end 114 of the swing crank are both located between the first swing transmission link 220 and the second swing transmission link 219. The working principle of the swing reversing mechanism 200 will be explained in detail below. After the reverse-forward swaying intermediate shaft 112 rotates, it will drive the swing seat 216 to swing. In this embodiment, the swing seat 216 is integrally formed with the second swing support arm 217 and the first swing support arm 221. Therefore, the swing of the swing seat 216 will cause the second swing support arm 217 and the first swing support arm 221 to swing. This, in turn, causes the first swing limiting link 222 and the second swing limiting link 218 to rotate, thereby changing the initial angle of the first swing limiting link 222 and the second swing limiting link 218, thus changing the stitch length and adjusting the reverse and forward stitches. Furthermore, the main shaft crank 104 and the main shaft 4 also have an eccentric structure. Therefore, when the main shaft 4 rotates, the output end 113 of the main shaft crank will reciprocate upward and downward. Figures 19-20 As shown, this causes shaft 24 to rotate around connecting shaft 25, resulting in two possible directions of motion, X1 or X2. This drives shaft 23 to move in the direction of Y1 or Y2. Since shaft 23 is fitted inside the input end 114 of the swing crank, it forms a pivot point for rotation. In actual use, after the drive motor rotates a certain angle, the second swing support arm 217 and the first swing support arm 221 stop swinging after a certain angle. At this point, connecting shaft 25 remains stationary, allowing shaft 24 to rotate around it. Furthermore, since shafts 23, 24, and connecting shaft 25 are all connected by rods or swing arms of fixed length, the distances between them are also relatively fixed. This is why... Figures 19-20As shown, when the connecting shaft 25 is in different positions, the shaft 23 can move in different directions. The figure also shows shafts 23, 24, and 25, but in the overall structure, the movement of the input end 114 of the swing crank is ultimately achieved. Therefore, correspondingly, an upper shaft hole 27 and a lower shaft hole 28 are formed at the upper and lower ends of the reverse and forward stitching swing crank 105, respectively. A presser foot lifting shaft 101 is fitted inside the upper shaft hole 27, and a horizontal tie rod 107 is fitted inside the lower shaft hole 28. The horizontal tie rod 107 connects to a rotating crank 106, and rotating the crank 106 causes the adjusting feed shaft 102 to rotate, thus achieving the reverse and forward stitching functions. Therefore, the lower end of the reverse and forward stitching swing crank 105 is hinged to the horizontal tie rod 107. The other end of the horizontal tie rod 107 is hinged to the rotating crank 106, which contains the adjusting feed shaft 102. Furthermore, by adjusting the rotation direction of the fabric feeding shaft 102, the direction of the presser foot feeding is changed, thereby achieving the functions of reverse stitching and forward stitching.

[0041] Example 3: Figure 1-7As shown, a flatbed sewing machine includes a frame 99. One end of the frame 99 is provided with an outer presser foot assembly 11 and an inner presser foot assembly 12, both of which include a presser foot rod 802. A presser foot lifting device is also provided within the frame 99. The presser foot lifting device includes a presser foot lifting bracket assembly 801, which is installed at the head of the frame 99 of the flatbed sewing machine. The function of the presser foot lifting bracket assembly 801 is to connect with the presser foot assembly 1 and ultimately lift the presser foot. A lifting shaft assembly 804 is installed within the crossbeam of the frame 99 and is used to lift or lower the presser foot lifting bracket assembly 801. In this embodiment, the lifting shaft assembly 804 drives the movement of the lifting bracket assembly 2 by rotation. It also includes a presser foot lifting motor 810, mounted on the frame 99, for driving the lifting shaft assembly 804; a rotating disk 809, mounted on the presser foot motor shaft 812 of the presser foot lifting motor 810; the rotating disk 809 is provided with a curved travel section 811, the curvature of the contour of the curved travel section 811 gradually increases; a linkage crank 808, one end of which is fixedly mounted on the presser foot lifting shaft 817 of the lifting shaft assembly 804, and the other end is mounted with a driven pin 813; the driven pin 813 abuts against the side wall of the curved travel section 811. Therefore, the gradually increasing curvature of the contour of the curved travel section 811 can achieve adjustment of the rate of change. Specifically, by increasing the curvature of the contour, after the motor has rotated through a certain fixed angle, the linkage crank 808 can rotate to a larger angle, and the rate of change will also increase, thus allowing the presser foot to pass through fabrics of different thicknesses. Furthermore, the axis of the driven pin 813 is parallel to, rather than collinear with, the axis of the presser foot motor 812. Therefore, the rotation of the presser foot lifting motor 810 drives the driven pin 813 to rotate within the curved travel section 811, which in turn drives the presser foot lifting shaft 817 to rotate, thereby lifting the presser foot lifting bracket assembly 801. Specifically, in actual use, the presser foot lifting motor 810 is connected to an electrical control system. By controlling the rotation angle of the presser foot lifting motor 810, the lifting height of the presser foot can be adjusted according to actual conditions. By controlling the start and stop times of the presser foot lifting motor 810, automatic lifting of the presser foot can be achieved.

[0042] Preferably, the curved travel portion 811 is an inner groove formed on the rotating disk 809. At least a portion of the wall surface of the curved travel portion 811 has a spiral curve 814 centered on the axis of the presser foot motor shaft 812. Preferably, a swing arm torsion spring 818 is sleeved on the presser foot lifting shaft 817. The swing arm torsion spring 818 includes a first pressure rod 819 and a second pressure rod 820. The first pressure rod 819 abuts against the inner sidewall of the frame 99; the second pressure rod 820 is disposed on the presser foot lifting shaft 817 and rotates synchronously with the presser foot lifting shaft 817. This technical solution specifically discloses a technical solution capable of driving the presser foot lifting shaft 817 to reset. In this embodiment, a swing arm torsion spring 818 is sleeved on the presser foot lifting shaft 817. By having a second pressure rod 820 mounted on the presser foot lifting shaft 817 and rotating synchronously with it, the swing arm torsion spring 818 deforms. Then, a first pressure rod 819 abuts against the inner wall of the frame 99, providing a reaction force that allows the presser foot lifting shaft 817 to return to its original position. In this embodiment, a lifting swing arm 807 is sleeved on the presser foot lifting shaft 817, rotating synchronously with it. The second pressure rod 820 abuts against the upper end face of the lifting swing arm 807. Synchronous rotation between the lifting swing arm 807 and the presser foot lifting shaft 817 is achieved by drilling a hole in the lifting swing arm 807 in the radial direction towards the presser foot lifting shaft 817, and using fasteners passing through this hole to achieve synchronization. Preferably, the lifting and pressing swing arm 807 includes a pressure roller portion 81 and a limiting portion 82. The pressure roller portion 81 is disposed between the rotating cam 806 and the second pressure rod 820; the second pressure rod 820 is disposed between the pressure roller portion 81 and the limiting portion 82.

[0043] Preferably, the pressure roller portion 81 is generally shaped like a "7", and the rotating cam 806 abuts against the inner side of the pressure roller portion 81. Preferably, a pressure foot wrench 805 is also provided on the outer side of the frame 99. One end of the pressure foot wrench 805 is connected to a wrench shaft 61, and the outer end of the wrench shaft 61 is fitted with the rotating cam 806. The outer edge of the rotating cam 806 abuts against the lifting and pressing swing arm 807. The rotating cam 806 is located inside the frame 99. Therefore, by rotating the pressure foot wrench 805, the wrench shaft 61 is rotated, and the rotation of the wrench shaft 61 drives the rotation of the rotating cam 806. Then, the rotating cam 806 drives the rotation of the lifting and pressing swing arm 807, ultimately realizing the rotation of the pressure foot lifting shaft 817, thus achieving the manual lifting and pressing foot function. Preferably, the end face of the rotating cam 806 is formed with a plurality of mounting holes 71, which are used to connect with the wrench shaft 61. The wrench shaft 61 drives the pressure foot lifting shaft 817 to rotate at different arcs by connecting with different mounting holes 71. Preferably, one end of the pressure foot wrench 805 is formed with a connecting shaft portion 62, and the wrench shaft 61 is sleeved in the connecting shaft portion 62; a wrench torsion spring 63 is sleeved on the connecting shaft portion 62, and the wrench torsion spring 63 includes a third pressure rod 64 and a fourth pressure rod 65. The third pressure rod 64 passes through the pressure foot wrench 805; the fourth pressure rod 65 passes through the frame 99. The above is a technical solution of adding a torsion spring to the pressure foot wrench 805 to assist the pressure foot wrench 805 in resetting. Preferably, one end of the presser foot lifting shaft 817 is fitted with a lifting swing arm 803 and rotates synchronously with the presser foot lifting shaft 817; the presser foot lifting bracket assembly 801 includes a lifting frame 815, and a presser foot rod is connected to the lower end of the lifting frame 815; a stop portion 816 is formed extending from one side of the lifting frame 815, and the lifting swing arm 803 abuts against the lower end face of the stop portion 816.

[0044] Example 4: Figure 21-25 As shown, a flat sewing machine includes a frame 99 and a base 98. A main shaft 4 is provided on the upper part of the frame 99, and a lower shaft 5 is provided on the lower part of the frame 99. The main shaft 4 and the lower shaft 5 are driven by a synchronous belt 6.

[0045] As described above, the flat sewing machine of this invention refers to a machine equipped with a main shaft 4 and a lower shaft 5, wherein the main shaft 4 and the lower shaft 5 are connected by a synchronous belt 6 for transmission. Correspondingly, an upper synchronous pulley 903 and a lower synchronous pulley 906 are respectively provided on the main shaft 4 and the lower shaft 5. A main motor 97 is located at one end of the main shaft 4, and the rotation of the main motor 97 sequentially drives the main shaft 4 and the upper synchronous pulley 903 to rotate. The winding device includes a tensioning wheel assembly 902 disposed within the frame 99. The tensioning wheel assembly 902 has a roller portion 911, which abuts against the synchronous belt 6 and rotates accordingly. Specifically, as shown... Figure 21As shown, the roller portion 911 extends along the length of the frame 99 from right to left through the support base 909 and abuts against the synchronous belt 6. It rotates by means of the rotation of the synchronous belt 6. A friction surface 912 is provided on the front side of the roller portion 911; the rotation of the roller portion 911 drives the rotation of the friction surface 912. A winding mechanism 901 is also provided at the front of the housing. The winding shaft of the winding mechanism 901 extends into the frame 99 and is equipped with a friction wheel 904. The winding mechanism 901 has a working state and a non-working state: when the winding mechanism is in the working state, the friction wheel 904 abuts against the friction surface 912 and is driven; when the winding mechanism is in the non-working state, the friction wheel 904 disengages from the friction surface 912.

[0046] The winding device described above cleverly utilizes the rotation of the synchronous belt 6 and uses the roller portion 911 of the tensioner assembly 902 to bear the rotation of the synchronous belt 6. When the winding mechanism is in working state, the friction wheel 904 is driven by abutting against the friction surface 912, thereby enabling the winding operation of the bobbin.

[0047] The winding mechanism described in this invention creatively changes its position from the traditional upper part of the main shaft to one side of the tensioner assembly 902. Moreover, since its location is precisely where the worker most commonly sees it during operation, the worker can easily and intuitively change the bobbin on the winding mechanism. The tensioner assembly 902 in this embodiment not only tensions the synchronous belt but also, through its structural design, allows the winding mechanism to rotate, achieving automatic winding of the bobbin. Figure 25 As shown, preferably, one end of the roller portion 911 is connected to an adjusting shaft 914, and the adjusting shaft rotates synchronously with the roller portion 911; the adjusting shaft 914 is eccentrically positioned with respect to the roller portion 911, and the adjusting shaft 914 is used to drive the roller portion 911 to rotate eccentrically through its own rotation, thereby adjusting the tension. The eccentric positioning of the adjusting shaft 914 and the roller portion 911 in this technical solution means that, in this embodiment, the axes of the adjusting shaft 914 and the roller portion 911 are parallel rather than coaxial. Specifically, in this embodiment, one end of the adjusting shaft 914 has a connecting hole 915, and the axis of the connecting hole 915 is not collinear with the adjusting shaft 914. Therefore, an eccentric positioning is formed between the adjusting shaft 914 and the roller portion 911. A connecting shaft 913 is provided inside the connecting hole 915, specifically as follows... Figure 25As shown, one end of the connecting shaft 913 has an internal hexagonal hole, and the other end has a cylindrical shaft portion. The connecting shaft 913, i.e., the cylindrical shaft portion, passes sequentially through the roller portion 911 and the adjusting shaft 914, and is connected to the adjusting shaft 914 through the connecting hole 915. This design, when the adjusting shaft 914 is rotated, changes the relative position between the roller portion 911 and the timing belt 6 due to the eccentric arrangement between the roller portion 911 and the adjusting shaft 914. That is, from... Figure 23 As you can see, the function of the tensioner assembly 902 is to enable the right side of the synchronous belt 6 to move left and right.

[0048] Moreover, as Figure 21-22 As shown, in this embodiment, the adjusting shaft 914 passes through the support base 909 along the length of the frame 99 and abuts against the timing belt 6. This positional design not only serves to tighten the timing belt but also avoids interfering with other parts of the existing flat sewing machine. Preferably, a connecting bearing 916 is sleeved on the inner side of the roller portion 911, and the connecting shaft 913 passes through the connecting bearing 916. Preferably, a connecting bearing 917 is formed on the outer edge of the adjusting shaft 914 in the radial direction, and the connecting bearing 917 is located on the outer side of the frame 99. Preferably, the winding mechanism 901 includes a winding base 905, a winding shaft 907 passes through the winding base 905, one end of the winding shaft 907 is connected to the friction wheel 904; the other end of the winding shaft 907 passes through the winding base 905 and extends to the outside of the winding base 905 to form a connecting end, which is used to connect the bobbin 908. A toggle wrench 910 is provided on the outer side of the connecting end. The toggle wrench 910 is used to switch the winding mechanism between a non-working state and a working state. How the switching is achieved is existing technology and will not be described in detail here.

[0049] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A flat sewing machine, comprising a thread winding device, and further comprising an inner presser foot assembly and an outer presser foot assembly, characterized in that: The winding device includes a frame, within which a main shaft and a lower shaft are arranged, and the main shaft and the lower shaft are connected by a synchronous belt; a main motor is arranged at one end of the main shaft, and the main motor is used to drive the main shaft to rotate. A tensioner assembly is installed inside the frame. The tensioner assembly has a roller part that abuts against the timing belt and rotates with it. A friction surface is provided on the front side of the roller section; The front part of the frame is also provided with a winding mechanism, and the winding shaft of the winding mechanism extends into the frame and is equipped with a friction wheel; The winding mechanism has a working state and a non-working state: When the winding mechanism is in operation, the friction wheel abuts against the friction surface and is driven. When the winding mechanism is not in operation, the friction wheel disengages from the friction surface; The upper ends of the inner and outer pressure foot assemblies are provided with an interaction adjustment device for the inner and outer pressure feet; the interaction adjustment device includes... The presser foot interaction mechanism drives the alternating lifting and lowering of the inner and outer presser foot assemblies; A oscillating crank mechanism is used to provide a reciprocating oscillating force to the presser foot interaction mechanism; The presser foot lifting crank mechanism includes a swing base with a first support arm and a second support arm on each side. Between the first and second support arms, a first limiting link, a first transmission link, the output end of the main shaft lifting crank, the input end of the swing crank, a second transmission link, and a second limiting link are sequentially arranged. The front end of the first support arm is hinged to the front end of the first limiting link, and the front end of the second support arm is hinged to the front end of the second limiting link. The rear ends of the first and second limiting links, the rear ends of the first and second transmission links, and the output end of the main shaft lifting crank are all coaxially hinged. The input end of the swing crank, the front end of the first and second transmission links are all coaxially hinged. The output end of the main shaft lifting crank and the input end of the swing crank are both located between the first and second transmission links. The presser foot lifting crank mechanism is used to convert the rotational motion of the main shaft into the reciprocating oscillation required by the swing crank mechanism. The swing amplitude adjustment mechanism includes a drive motor with an eccentric wheel mounted on its shaft. A swing element abuts against the surface of the eccentric wheel, and a transmission shaft is fixedly mounted on the other side of the swing element. The other end of the transmission shaft is fixedly connected to the swing seat of the presser foot lifting crank mechanism. A strip groove is provided on the side of the swing element closest to the motor shaft, and the eccentric wheel is positioned within the strip groove, with the upper and lower sidewalls of the strip groove simultaneously abutting against the upper and lower sides of the eccentric wheel. The transmission shaft and the main shaft are arranged parallel to each other. The swing amplitude adjustment mechanism is used to adjust the amplitude of the reciprocating swing of the presser foot lifting crank mechanism.

2. The flat sewing machine according to claim 1, characterized in that, One end of the roller is connected to an adjusting shaft, and the adjusting shaft rotates synchronously with the roller. The adjusting shaft is eccentrically set with the roller, and the adjusting shaft is used to drive the roller to rotate eccentrically by its own rotation, thereby adjusting the tension. One end of the adjusting shaft is formed with a connecting hole, and a connecting shaft is provided in the connecting hole. The connecting shaft passes through the roller part and the adjusting shaft in sequence, and is connected to the adjusting shaft through the connecting hole.

3. The flat sewing machine according to claim 1, characterized in that, The presser foot interaction mechanism includes a lifting seat, a lifting bracket, an inner presser foot assembly, and an outer presser foot assembly; The lifting seat is mounted on the lifting bracket, and an outer pressure foot rod is provided on the rear side of the lower part of the lifting seat, and an inner pressure foot rod is provided on the front side of the lower part of the lifting seat; the rear side of the lower part of the lifting seat, the lifting bracket, and the upper end of the outer pressure foot rod are coaxially hinged together; the front side of the lower part of the lifting seat is hinged to the upper end of the inner pressure foot rod. The swing crank mechanism includes an intermediate shaft, with a swing crank mounted in the middle of the intermediate shaft; a lifting crank is installed at one end of the intermediate shaft that extends toward the presser foot interaction mechanism; the lifting crank drives the lifting seat to rotate via a push-pull rod.

4. The flat sewing machine according to claim 1, characterized in that, The main shaft is equipped with a swing reversing mechanism and a reverse and forward stitching drive motor. The oscillating reversing mechanism is used to convert the rotational motion of the main shaft into the reciprocating oscillation required by the feed shaft; The reverse and forward stitching drive motor has a presser foot motor shaft that drives a swing reversing mechanism via a crank assembly. The swing reversing mechanism swings and adjusts around the intermediate shaft of the reverse and forward stitching.

5. The flat sewing machine according to claim 4, characterized in that, The crank assembly includes a reverse-sew eccentric wheel and an eccentric connecting rod. The reverse-sew eccentric wheel is mounted on the motor shaft. One end of the eccentric connecting rod is fitted onto the reverse-sew eccentric wheel, and the other end of the eccentric connecting rod is hinged to a rocker arm. The other end of the rocker arm is fixed to the reverse-sew intermediate shaft.

6. The flat sewing machine according to claim 5, characterized in that, The swing reversing mechanism includes, The second swing seat has a first swing support arm and a second swing support arm respectively on its two sides; Between the first swing support arm and the second swing support arm, a first swing limiting link, a first swing transmission link, the output end of the main shaft crank, the input end of the swing crank, the second swing transmission link, and the second swing limiting link are sequentially arranged. The front end of the first swing support arm is hinged to the front end of the first swing limiting link. The front end of the second swing support arm is hinged to the front end of the second swing limiting link. The rear ends of the first swing limiting link, the second swing limiting link, the first swing transmission link, the second swing transmission link, and the output end of the main shaft crank are all coaxially hinged. The input end of the forward and reverse sway crank, the front end of the first sway transmission link, and the front end of the second sway transmission link are all coaxially hinged. The output end of the main shaft crank and the input end of the swing crank are both located between the first swing transmission link and the second swing transmission link. The lower end of the forward and reverse stitching swing crank is hinged to a horizontal tie rod, and the other end of the horizontal tie rod is hinged to a rotating crank, with a fabric feeding shaft sleeved inside the rotating crank.

7. The flat sewing machine according to claim 1, characterized in that, It also includes a presser foot lifting device, which includes... The presser foot lifting bracket assembly is installed at the head of the frame of the flat sewing machine; A lifting shaft assembly, mounted within the crossbeam of the frame, is used to raise or lower the presser foot lifting bracket assembly. A presser foot lifting motor, mounted on the frame, is used to drive the lifting shaft assembly; A rotating disk is mounted on the shaft of the presser foot lifting motor; the rotating disk is provided with a curved travel section, the curvature of the contour line of the curved travel section gradually increases; The linkage crank has one end fixedly mounted on the pressure foot lifting shaft of the lifting shaft assembly, and the other end is equipped with a driven pin. The driven pin is pressed against the curved travel section.

8. The flat sewing machine according to claim 7, characterized in that, The curved travel section is an inner groove formed on the rotating disk, or the curved travel section is the outer contour of the rotating disk; At least a portion of the contour curve of the curved travel section is a spiral line, with the axis of the presser foot motor shaft as the center; The presser foot lifting shaft is fitted with a swing arm torsion spring, which includes a first pressure rod and a second pressure rod. The first pressure rod abuts against the inner side wall of the frame; the second pressure rod is mounted on the presser foot lifting shaft and rotates synchronously with the presser foot lifting shaft. The presser foot lifting shaft is fitted with a lifting and pressing swing arm, which rotates synchronously with the presser foot lifting shaft; the second pressure rod abuts against the upper end face of the lifting and pressing swing arm; The lifting and pressing swing arm includes a pressure roller part and a limiting part. The pressure roller part is disposed between the rotating cam and the second pressure rod. The second pressure rod is disposed between the pressure roller part and the limiting part. The outer side of the frame is also equipped with a press foot wrench. One end of the press foot wrench is connected to a wrench shaft. A rotating cam is sleeved on the outer end of the wrench shaft. The outer edge of the rotating cam abuts against a lifting and pressing swing arm. The end face of the rotating cam is formed with a number of mounting holes for connecting with the wrench shaft. The wrench shaft drives the pressure foot lifting shaft to rotate by different arcs by connecting with different mounting holes. One end of the presser foot wrench is formed with a connecting shaft, and the wrench shaft is sleeved in the connecting shaft; a wrench torsion spring is sleeved on the connecting shaft, and the wrench torsion spring includes a third pressure rod and a fourth pressure rod, the third pressure rod passing through the presser foot wrench; the fourth pressure rod passing through the frame. One end of the presser foot lifting shaft is fitted with a lifting swing arm, which rotates synchronously with the presser foot lifting shaft; the presser foot lifting bracket assembly includes a lifting frame, and the lower end of the lifting frame is connected to a presser foot rod; one side of the lifting frame extends to form an abutment portion, and the lifting swing arm abuts against the lower end face of the abutment portion.

Images