Driving mechanism for presser foot lifting cam of sewing machine

Abstract

The utility model discloses a presser foot lifting cam driving mechanism of a sewing machine, and relates to the technical field of sewing machines. The motor and the cam assembly are installed on the rear window plate of the sewing machine on the outer side of the sewing machine, the space in the sewing machine is not occupied, and meanwhile installation and maintenance are convenient. The sewing machine does not need to be disassembled when the cam needs to be lubricated. And the synchronous transmission rod for transmitting the rotation of the cam is in contact with the cam through the roller, so that the friction force is further reduced, the abrasion is reduced, the response speed of the sewing machine can be improved, the cam transmits movement and force more stably, the change of the rotation direction of the motor can be quickly responded, the lifting response speed of the presser foot is improved, and the production efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the field of sewing machine components, and particularly relates to a cam driving mechanism for lifting and pressing the presser foot of a sewing machine. Background Art

[0002] A sewing machine is an important device in human light industrial production, especially in the textile industry. Almost all the "clothes" in people's daily life of "food, clothing, shelter and transportation" need to be made by a sewing machine in modern society. Only by processing and sewing fabrics with a sewing machine can the cloth be made into clothes suitable for people's body sizes to wear.

[0003] However, at present, the control driving mechanism for lifting and pressing the presser foot of a sewing machine has a relatively fixed lifting height for the presser foot of the sewing machine. The mechanism occupies too much space inside the sewing machine and there is a risk of interfering with the movement of the main shaft of the sewing machine and other internal components. Moreover, the existing mechanisms for driving the structure of the presser foot of a sewing machine generally adopt fixed connection or hinge connection. The connection between each group is a rigid connection without allowance. When a certain component fails, it may cause other components to fail together. And the load at startup between the connecting rods is large, and the requirement for the load of the motor is high.

[0004] In the prior art, there are solutions for directly controlling the lifting and lowering of the presser foot by a motor. For example, in the "Sewing Machine Integrating Lifting and Pressing the Presser Foot and Adjusting Thread Tension" disclosed in the publication number WO2021227260A1, it uses a driving motor and controls the tension of the external surface thread during the lifting and lowering of the presser foot of the sewing machine through two different transmission mechanisms. However, it all uses connecting rods to transmit power, and it is easy to have problems such as jitter and instability during opening and closing. At the same time, the response speed to the rapid forward and reverse rotation of the motor is slow, and it is difficult to start at any position in the stroke. Summary of the Utility Model

[0005] Aiming at the deficiencies of the prior art, the utility model provides a cam driving mechanism for lifting and pressing the presser foot of a sewing machine. By installing a cam on the output shaft of the motor as the driving component of the presser foot mechanism, and only in contact connection with the synchronous transmission rod, if a certain component gets stuck, it is not easy to damage other components. And when opening and closing, the torque is transmitted more smoothly and comfortably through the cam. There is no dead point position in the movement of the mechanism, and the presser foot mechanism of the sewing machine can be started at any position in the stroke.

[0006] The utility model realizes the above technical purpose through the following technical means.

[0007] A cam driving mechanism for lifting and pressing the presser foot of a sewing machine includes a presser foot of the sewing machine and a driving motor. The output shaft of the driving motor is in transmission connection with a cam, the cam is in transmission connection with a synchronous transmission rod, and the second transmission part of the synchronous transmission rod is in transmission connection with a transmission connecting rod.

[0008] When the cam is in the initial state, the synchronous transmission rod is located at the first arc segment between the first concave portion and the second concave portion.

[0009] Furthermore, the cam has a three-layer structure. The layer close to the input shaft of the driving motor is the input section, the outermost layer is the cam disk, and the transition section is located between the input section and the cam disk. An opening is provided at a position perpendicular to the axis of the fixing hole of the cam in the transition section.

[0010] Furthermore, a cam surface is provided on the side surface of the cam disk of the cam. One end of the cam surface is connected to the lowest point of the first concave portion, and the other end of the cam surface is connected to the highest point of the second concave portion.

[0011] There is an arc segment between the connection positions of the cam surface and the second concave portion, which is the second arc segment.

[0012] Furthermore, an opening is provided in the input section of the cam. The opening is collinear with the center of the fixing hole of the cam. Both sides of the opening are adjustment platforms. An adjustment hole is provided through the middle of the adjustment platforms, and the positions of the adjustment holes on the upper and lower adjustment platforms are the same.

[0013] Furthermore, the first transmission part of the synchronous transmission rod is in direct contact with the cam. The first transmission part is composed of a contact part and a transmission part.

[0014] Furthermore, the contact part of the first transmission part is a disk-shaped component. A hole for cooperating with the mounting shaft of the transmission part is provided on the disk surface. A ring-shaped roller is installed at one end of the first transmission part. An adjustment platform is provided at the other end of the first transmission part. The adjustment platforms are symmetrically distributed. The side surface of the adjustment platform is tangent to the first transmission part. Mutually cooperating and penetrating adjustment holes are provided on the two symmetrically distributed adjustment platforms.

[0015] The transmission part of the first transmission part is fixedly connected to the mounting plate of the synchronous transmission rod.

[0016] Furthermore, the second transmission part of the synchronous transmission rod and the transmission part on the first transmission part of the synchronous transmission rod are the same rod, which is the middle rod. The second transmission part is hinged to the mounting plate on the synchronous transmission rod.

[0017] Furthermore, a transmission disk and a transmission rod are provided at the end of the second transmission part. The middle rod and the transmission rod are respectively located at both ends of the disk surface of the transmission disk, and are on different disk surfaces on both sides of the transmission disk. Two semi-circles with different radii are provided at both ends of the disk surface of the transmission disk. The tangents on both sides of the two semi-circles are collinear, and the two semi-circles are integrated through the cut surfaces on both sides.

[0018] Further, the transmission rod of the second transmission part is connected to the transmission connecting rod, the transmission connecting rod is in a shape of a capital letter "L", and the turning point of the transmission connecting rod is fixed on the sewing machine.

[0019] Further, it is characterized in that the driving motor is installed on the rear window plate of the sewing machine, and the output shaft of the driving motor is parallel to the main shaft of the sewing machine.

[0020] The beneficial effects of the present utility model are as follows:

[0021] In the present utility model, both the motor and the cam assembly are installed on the rear window plate on the outside of the sewing machine, without occupying the space inside the sewing machine. At the same time, the installation is convenient, and the maintenance is also convenient. When the cam needs to be lubricated, it is more convenient without disassembling the sewing machine. The synchronous transmission rod for transmitting the rotation of the cam contacts the cam through a roller, further reducing the friction force and wear, which can improve the response speed of the sewing machine. The transmission of motion and force by the cam is more stable, and it can quickly respond to the change of the rotation direction of the motor, improving the lifting and lowering response speed of the presser foot and increasing the production efficiency.

[0022] Figure 1 It is a schematic perspective view of the presser foot lifting cam driving mechanism of the sewing machine of the present utility model.

[0023] Figure 2 It is a schematic perspective view of the cam of the present utility model.

[0024] Figure 3 It is the front view of the cam structure of the present utility model.

[0025] Figure 4 It is the side view of the cam structure of the present utility model.

[0026] Figure 5 It is a schematic perspective view of the synchronous transmission rod of the present utility model.

[0027] In the figure, 1 - driving motor, 2 - cam, 21 - cam disc, 211 - first concave part, 212 - second concave part, 213 - cam surface, 214 - first arc segment, 215 - second arc segment, 22 - fixing hole, 23 - transition segment, 231 - transition segment opening, 24 - input segment, 241 - adjusting table, 242 - adjusting hole, 3 - synchronous transmission rod, 31 - first transmission part, 311 - roller, 312 - adjusting table, 313 - adjusting hole, 32 - bushing, 33 - mounting plate, 34 - second transmission part, 341 - transmission disc, 342 - transmission rod. Specific embodiments

[0028] The following further illustrates the present utility model in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present utility model is not limited thereto.

[0029] Embodiment:

[0030] As shown Figures 1 to 5 in the figure, the drive motor 1 is installed on the outside of the sewing machine, and the output shaft of the drive motor 1 is installed in a direction parallel to the main shaft of the sewing machine. The drive motor 1 is not directly installed on the rear window plate 4 of the sewing machine, but through a vertical motor bracket. After the motor bracket is fixedly installed on the rear window plate 4 of the sewing machine, the drive motor 1 is installed on the motor bracket. This installation can reduce the installation area required by the drive motor 1 on the rear window plate 4 of the sewing machine, and is suitable for reliably installing the drive motor when the surface support area is small.

[0031] In the present utility model, both the drive motor 1 and the output shaft of the drive motor 1 are installed on one side of the rear window plate 4 of the sewing machine, located outside the sewing machine, which is beneficial to installing a larger drive motor 1, and it is more convenient to perform operations such as maintenance and lubrication on components such as the drive motor 1 located outside the sewing machine. It makes the installation of the drive motor 1 and other components more convenient, and is also beneficial to the positioning installation between the components and the drive motor 1.

[0032] The output shaft of the drive motor 1 is connected to the cam 2. Specifically, it starts from the input section 24 of the cam 2, passes through the transition section 23 of the cam 2, and finally passes out to the outer end face of the cam disc 21 of the cam 2, and passes through the entire cam 2 through the fixing hole 22 on the cam 2.

[0033] The connection between the output shaft of the drive motor 1 and the cam 2 is a fixed connection, so that the rotation of the output shaft of the drive motor 1 after being energized can drive the rotation of the cam 2, and then the motion is transmitted to other components through the cam 2. Because in the present utility model, the torque required for the output shaft of the drive motor 1 to drive the sewing machine presser foot lifting mechanism is relatively small, so the output shaft does not need to be fixed by key connection. Although key connection makes the transmission process firm and does not slip, it is generally difficult to disassemble for the reliability of the transmission after connection. When the components are damaged, maintenance and replacement are not convenient enough.

[0034] Therefore, in the present utility model, after the cam 2 is connected to the output shaft of the drive motor 1, a large pressure is applied to the output shaft of the drive motor 1 to ensure that the cam 2 can be firmly clamped and installed on the output shaft of the drive motor 1 and can rotate synchronously with the output shaft of the drive motor 1. Therefore, an opening is provided in the input section 24 of the cam 2, and on both sides of the opening are the adjustment platforms 241 of the input section 24 of the cam 2, and adjustment holes 242 of the input section 24 of the cam 2 are penetrated through the two adjustment platforms 241 of the input section 24 of the cam 2.

[0035] The outer shape of the cam 2 is an annular cylinder. There is an opening on one side of it. Two platforms extend outward in parallel from the opening side. These two platforms are not only parallel to each other on the inner side, but also parallel to each other on the outer side. The gap between the inner parallel planes is the extended section of the opening. The shape of the input section 24 of the wheel 2 is designed in such a way that on the one hand, it can facilitate the cam 2 to adapt to the output shafts of drive motors 1 with different shaft diameters, ensuring that drive motors 1 with output shaft diameters within a certain range can be adapted to the cam 2. On the other hand, it ensures that even if the diameter of the output shaft of the drive motor 1 is slightly smaller than the diameter of the fixing hole 22 of the cam 2, the user can still tighten the fastener installed on the adjustment hole 242 of the input section 24 of the cam 2 for adjusting the diameter of the fixing hole 22 of the cam 2, so as to reduce the gap between the two adjustment platforms 241 on the input section 24 of the cam 2, thereby reducing the diameter of the fixing hole 22 on the cam 2. Furthermore, it can be realized that the cam 2 can be adapted to the output shafts of drive motors 1 with different shaft diameters within a certain range, and the cam 2 can be locked and fixed with the output shaft of the drive motor 1, so that the output shaft of the drive motor 1 can drive the cam 2 to rotate synchronously.

[0036] Structurally, the cam 2 can be divided into three parts. The first part that comes into contact with the output shaft of the drive motor 1 is the input section 24, which is located on the outermost side of the cam 2. And the part that plays a role in driving other components is the cam disk 21. It is sandwiched between the input section 24 of the cam 2 and the cam disk 21 of the cam 2, and is penetrated by the same hole, that is, the fixing hole 22 of the cam 2, together with the input section 2 of the cam 2, the cam disk 21 of the cam 2, and the transition section of the cam 2.

[0037] A small window with an angle of 60° to 90° is opened on the transition section 23 of the cam 2, which is the transition section opening 231. The opening direction of the transition section opening 231 on the transition section 23 of the cam 2 is consistent with the extending direction of the adjustment platform 241 of the input section 24 of the cam 2.

[0038] The most important functional component on the cam 2 is the cam disk 21. The cam disk 21 is provided with a first concave portion 211, a second concave portion 212, and a cam surface 231. There is an arc between the first concave portion 211 and the second concave portion 212, which is the first arc segment 214. The first arc segment 214 is the transition part during the transmission process of the cam 2. When the synchronous transmission rod 3 is placed on this transition part, there will be no height fluctuation on the side surface of the cam disk 21 of the cam 2 during the rotation of the cam 2. Generally, when the motor starts, since its static balance is broken, at this time, the output shaft of the drive motor 1 will not rotate smoothly, but will generate jitter.

[0039] Therefore, setting the first arc segment 214 between the first concave portion 211 of the cam disk 21 and the second concave portion 212 of the cam disk 21 can reduce the influence of the jitter during the start of the drive motor 1 on the movement of the sewing machine presser foot lifting.

[0040] The lowest point of the first concave portion 211 of the cam disk 21 is connected to one end of the cam surface 213 of the cam disk 21 of the cam 2. This is the lowest position during the movement of the synchronous transmission rod 3 and also the position when the presser foot of the sewing machine is at the bottommost. Therefore, it can be regarded as the initial position during the movement of the presser foot of the sewing machine. The other end of the cam surface 213 of the cam disk 21 of the cam 2 is connected to one end of the highest point of the second concave portion 212. At the same time, there is an arc between the highest point of the second concave portion 212 and the cam surface 213 of the cam disk 21 of the cam 2, which is the second arc segment 215.

[0041] The second arc segment 215 also plays a buffering role during the movement of the presser foot mechanism. If the first concave portion 211 formed by the connection of the first arc segment 214 and the cam surface 213 is the initial position during the movement of the cam 2 and the presser foot of the sewing machine, then the intermediate transition segment where the second concave portion 212 is connected to the cam surface 213, namely the second arc segment 215, is the end position during the movement of the cam 2 and the presser foot of the sewing machine.

[0042] When the cam 2 moves to this position, the presser foot of the sewing machine also reaches the highest height. At this time, what needs to be done is to lower the presser foot of the sewing machine to reduce the height of the presser foot of the sewing machine in order to complete the next process of sewing. To lower the height of the presser foot of the sewing machine, it is necessary to reverse the driving motor 1 to achieve this. Therefore, the driving motor 1 is involved in two processes of stopping and restarting here. The stopping of the driving motor 1 is to change the driving motor 1 from the moving state to the stationary state, and the dynamic balance is broken. At this time, the driving motor 1 will generate a certain vibration. Therefore, the second arc segment 215 buffers the motor. When the driving motor 1 starts, the driving motor 1 changes from the stationary state to the moving state, and the balance is broken again. The driving motor 1 will also vibrate before reaching the balance. At this time, the second arc segment 215 plays a buffering role again.

[0043] The distance from the point on the cam surface 213 of the cam disk 21 of the cam 2 to the rotation center of the cam 2, that is, the center axis of the fixed hole 22 of the cam 2, increases linearly until the second arc segment 212. The distance from the point on the cam surface 213 to the center axis of the fixed hole 22 increases steadily on the cam 2. Therefore, the input of the lifting and lowering movement of the presser foot of the sewing machine is stable and not prone to oscillation and fluctuation.

[0044] By driving the cam 2 to rotate forward and backward by the driving motor 1, the response speed is very fast, the speed of the presser foot is faster and more flexible, which is convenient for control and can improve production efficiency.

[0045] The driving motor 1 needs to transfer the rotation to the sewing machine presser foot lifting mechanism and convert it into the lifting motion of the sewing machine presser foot. It is not enough to rely only on the cam 2. It is also necessary to bring the cam surface 213 of the cam disc 21 of the cam 2 into contact with the synchronous transmission rod 3, so as to transfer the torque output from the output shaft of the driving motor 1 from the cam 2 to the synchronous transmission rod 3.

[0046] The synchronous transmission rod 3 consists of three parts, namely the first transmission part 31, the mounting plate 33 and the second transmission part. The first transmission part 31 of the synchronous transmission rod 3 is the main component that contacts the cam 2. The first transmission part 31 consists of two parts, the contact part and the transmission part. The transmission part directly contacts the cam surface of the cam 2, and the transmission part is tightly connected to the contact part and can rotate synchronously with the contact part.

[0047] The main body of the contact part of the first transmission part 31 is disc-shaped. One side of the disc extends into a cuboid, and at the other end of the cuboid, a roller 311 is hinged. While the roller 311 can roll, it can also roll relative to its mounting position on the cuboid.

[0048] On the side of the disc opposite to the cuboid, there is an opening similar to the input section 23 of the cam 2. On both sides of the opening, two adjustment platforms 312 are also distributed in parallel. Corresponding adjustment holes 313 are also provided on the two adjustment platforms 312. However, different from the adjustment platform 241 of the cam 2, the end surface of the adjustment platform on the first transmission part 31 away from the opening is inclined and tangent to the disc. The inclination angle is within 10° to 20°. Through the adjustment platform 312 and the adjustment hole 313, the contact part and the transmission part can be firmly connected together, enabling the contact part to drive the transmission part to rotate together.

[0049] In the synchronous transmission rod 3, the middle rod between the first transmission part 31 and the second transmission part 34 is one rod. At the position of the first transmission part 31, this rod is sleeved inside the bushing 32 extended from the mounting plate 33, and the other end of the bushing abuts against the position of the contact part.

[0050] The mounting plate 33 is fixed to the side of the rear window plate 4 of the sewing machine located inside the sewing machine, and is used to restrict any movement of the synchronous drive rod 3 other than rotation. Therefore, the second transmission part 34 is obviously located inside the sewing machine. In the second transmission part 34, the other end of the intermediate rod is connected to the transmission disk 341. At both ends of the disk surface of the transmission disk, there are two semi-circles with different radii. The tangents on both sides of the two semi-circles are collinear, and the two semi-circles form an integral body through the cut surfaces on both sides. Among these two semi-circles, one semi-circle has a larger diameter and the other has a smaller diameter. The end face of the intermediate rod is located at the center of the semi-circle with the larger diameter, while on the other side of the transmission disk 341, at the center position of the semi-circle with the smaller diameter, there is a transmission rod 342. The transmission rod 342 and the intermediate rod are distributed on the two end faces of the transmission disk 341. Therefore, when the contact part of the first transmission part 31 rotates, the transmission rod 342 of the second transmission part 34 will also rotate by the same angle.

[0051] In contact connection with the transmission rod 342 and further transmitting the rotation is the transmission connecting rod 5. The transmission connecting rod 5 is in a shape of a seven, and there is an opening at the turning point of the transmission connecting rod 5. The transmission connecting rod 5 is fixed inside the sewing machine, so that the transmission connecting rod 5 can only rotate relative to the sewing machine. One folded edge of the transmission connecting rod 5 contacts the cylindrical surface of the transmission rod 342 and can be used to transmit the rotation to raise this folded edge. On the other folded edge of the transmission rod, there is also an opening below the opening at the turning point, which can be used to install a fixing ring. A pull rod is installed on the fixing ring, and power is provided for the presser foot lifting mechanism of the sewing machine through the pull rod, so as to drive the presser foot lifting mechanism to move up and down.

[0052] As Figure 1 shown, the dynamic movement process of the presser foot cam drive mechanism of the sewing machine of the present invention is described here. It is defaulted here that the presser foot of the sewing machine and the cam 2 start to move from the default position; and when the drive motor 1 rotates forward, it drives the presser foot of the sewing machine to move upward, and when the drive motor 1 rotates in reverse, it drives the presser foot of the sewing machine to move downward.

[0053] First, after the entire device is installed in place, start the drive motor 1. When the drive motor 1 rotates forward, the roller 311 of the synchronous drive rod 3 starts to leave the first concave part 211, rotates along the cam surface 213 to the position of the second arc section 215. The transmission disk 341 of the synchronous drive rod 3 starts to swing clockwise. The height of the transmission rod 342 is steadily raised. One end of the folded edge of the transmission connecting rod 5 in contact with the transmission rod 342 away from the middle turning point is raised. The transmission connecting rod 5 rotates around the turning point, driving the other end of the other folded edge of the transmission connecting rod 5 away from the turning point to rotate downward and to the left, thereby lifting the presser foot of the sewing machine and realizing the lifting movement of the presser foot of the sewing machine.

[0054] After the presser foot of the sewing machine is lifted to the highest point, that is, after the roller 311 moves to the second arc segment 215, the driving motor 1 starts to reverse, and the roller 311 starts to roll from the second arc segment 215 along the cam surface 213 to the first concave surface 211. As the driving motor 1 rotates, the synchronous transmission rod 3 rotates counterclockwise at this time, and the transmission disk 341 also rotates counterclockwise synchronously. The height of the transmission rod 342 is steadily reduced under the gravity and the limit of the cam surface 213 of the cam 2, and the corresponding presser foot of the sewing machine also drops under the action of gravity, pulling the hem of the transmission connecting rod 5 that is not in contact with the transmission rod 342 outward and upward, but the hem in contact with the transmission rod 342 is steadily reduced under the limit of the transmission rod 342, so the presser foot of the sewing machine is also synchronously and steadily reduced. After the roller 311 returns to the first concave surface 211, the presser foot of the sewing machine also falls completely, and a lifting cycle of the presser foot of the sewing machine has been completed.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A cam drive mechanism for a sewing machine presser foot lifter, comprising a sewing machine presser foot lifter and a drive motor (1), characterized in that, The output shaft of the driving motor (1) is in transmission connection with the cam (2), the cam (2) is in transmission connection with the synchronous transmission rod (3), and the second transmission part (34) of the synchronous transmission rod (3) is in transmission connection with the transmission connecting rod (5); When the cam (2) is in the initial state, the synchronous transmission rod (3) is located at the first arc segment (214) between the first concave part (211) and the second concave part (212).

2. The sewing machine presser foot lifting cam drive mechanism according to claim 1, characterized in that, The cam (2) has a three-layer structure. Among them, the layer close to the input shaft of the driving motor (1) is the input section (24), the outermost layer is the cam disc (21), and the transition section (23) is located between the input section (24) and the cam disc (21). An opening is provided at the position where the filtering section (23) is perpendicular to the axis of the fixing hole (22) of the cam (2).

3. The sewing machine presser foot lifting cam drive mechanism according to claim 1, wherein A cam surface (213) is provided on the side surface of the cam disc (21) of the cam (2). One end of the cam surface (213) is connected to the lowest point of the first concave part (211), and the other end of the cam surface (213) is connected to the highest point of the second concave part (212); There is an arc segment between the connection position of the cam surface (213) and the second concave part (212), which is the second arc segment (215).

4. The sewing machine presser foot lifting cam drive mechanism according to claim 1, characterized in that An opening is provided in the input section (24) of the cam (2). The opening is collinear with the center of the fixing hole (22) of the cam (2). The two sides of the opening are adjusting platforms (241). An adjusting hole (242) is provided through the middle position of the adjusting platforms (241). The positions of the adjusting holes (242) on the upper and lower adjusting platforms (241) are the same.

5. The presser foot lifting cam drive mechanism of a sewing machine according to claim 1 or 2 or 3 or 4, characterized in that The first transmission part (31) of the synchronous transmission rod (3) is in direct contact with the cam (2). The first transmission part (31) is composed of a contact part and a transmission part.

6. The presser foot lifting cam drive mechanism of the sewing machine according to claim 5, characterized in that, The contact part of the first transmission part (31) is a disc-shaped component. A hole for cooperating with the mounting shaft of the transmission part is provided on the disc surface. A circular roller (311) is installed at one end of the first transmission part (31). An adjusting platform (312) is provided at the other end of the first transmission part (31). The adjusting platforms are symmetrically distributed. The side surface of the adjusting platform is tangent to the first transmission part (31). Mutually cooperating and penetrating adjusting holes (313) are provided on the two symmetrically distributed adjusting platforms; The transmission part of the first transmission part (31) is fixedly connected to the mounting plate (33) of the synchronous transmission rod (3).

7. The sewing machine presser foot lifting cam drive mechanism according to claim 1 or 2 or 3 or 4 or 6, characterized in that, The second transmission part (34) of the synchronous transmission rod (3) and the transmission part on the first transmission part (31) of the synchronous transmission rod (3) are the same rod, which is the middle. The second transmission part (34) is hinged to the mounting plate (33) on the synchronous transmission rod (3).

8. The presser foot lifting cam drive mechanism of a sewing machine according to claim 7, characterized in that, At the end of the second transmission part (34), there are a transmission disc (341) and a transmission rod (342). The intermediate rod and the transmission rod (342) are respectively located at both ends of the disc surface of the transmission disc (341), and at the same time, on different disc surfaces on both sides of the transmission disc (341). At both ends of the disc surface of the transmission disc (34), there are two semi - circles with different radii. The tangents on both sides of the two semi - circles are collinear, and the two semi - circles form an integral body through the cut surfaces on both sides.

9. The presser foot lifting cam drive mechanism of the sewing machine according to claim 8, characterized in that, The transmission rod (342) of the second transmission part (34) is connected to the transmission connecting rod (5). The transmission connecting rod (5) is in a shape of 'L', and the turning point of the transmission connecting rod (5) is fixed on the sewing machine.

10. The sewing machine presser foot lifting cam drive mechanism according to claim 1 or 2 or 3 or 4 or 6 or 8 or 9, characterized in that, The driving motor (1) is installed on the rear window plate (4) of the sewing machine, and the output shaft of the driving motor (1) is parallel to the main shaft of the sewing machine. It should be noted that in the original text, the description of the shape of the "transmission connecting rod (5)" as "seven - shaped" seems incorrect. It is more likely to be "L - shaped" as translated above. If this is not what you intended, please check the original text for accuracy.

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