Presser foot lifting crank driving mechanism of sewing machine

Abstract

The utility model discloses a presser foot lifting crank driving mechanism of a sewing machine, and relates to the technical field of sewing machines. The driving motor is adopted to control the rotation of the driving crank, so that the rotation angle of the driving crank can be accurately controlled, the movement of the transmission connecting rod is further controlled, and the lifting height of the presser foot lifting mechanism can also be accurately controlled. Different presser foot lifting heights can be adopted according to different cloth required to be fed into different lengths, so that the characteristics of the cloth and working requirements can be better met, the situation that a presser foot controlled by an electromagnet generally only has a lifting state and a falling state is avoided, and more complex sewing requirements can be met.

Description

Technical Field

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

[0002] As a product of the first industrial revolution in human history, although the sewing machine has a long history of birth, it is closely related to human daily life. After hundreds of years of development, most sewing machines are now driven by electricity and can be controlled by a computer or PLC. However, for the movement of the sewing machine presser foot mechanism, the current mainstream sewing machines still use electromagnets for control. The electromagnet requires a large force to open and close, and the electromagnet has only two states of on and off, which is not suitable for more precise control of the sewing machine presser foot.

[0003] Although there is also a method in the prior art to directly control the presser foot by a motor, such as the "presser foot lifting mechanism for a sewing machine" disclosed in the patent No. CN219239945U, which directly installs the driving motor at the presser foot position of the sewing machine through a connecting rod mechanism to control the presser foot. However, when the motor is installed in this position, on the one hand, it affects the sight of textile workers during sewing, and at the same time, it will also interfere with the thread take-up lever and the thread supply assembly of the sewing machine, which has a certain negative impact on the working process of the sewing machine. Summary of the Utility Model

[0004] Aiming at the problem that in the existing sewing machine, the motor is directly used to control the presser foot, the installation position of the motor is too far forward, which is prone to interfere with the thread take-up lever and the thread supply assembly of the sewing machine during work, and affects the sight of workers, and it is necessary to redesign the thread supply assembly to adapt to the installation of the motor, and all use hole-shaft connections. When the motor is stuck, the torque is very large, which is easy to damage the components inside the sewing machine. The utility model provides a sewing machine presser foot lifting crank drive mechanism, which installs the motor and the main drive mechanism components at one end far away from the sewing machine presser foot. The driving motor is installed outside the sewing machine. In this way, the motor and the drive mechanism components are close to the machine column of the sewing machine, shortening the length of the force arm and reducing the force on the machine column. Because the sewing machine is a cantilever beam structure and mainly relies on the machine column for support, the farther the components are from the machine column, the longer the force arm and the greater the force on the machine column. The drive mechanism of the utility model has a compact design and occupies very little space in the already scarce internal space of the sewing machine and will not interfere with other components inside the sewing machine. The utility model connects a lightweight alloy rod, which has a small mass and high strength, between the drive mechanism and the presser foot, and can efficiently and reliably transmit force and motion to control the lifting of the sewing machine presser foot. The utility model is driven by a motor and can accurately control the lifting height of the presser foot. Compared with the traditional electromagnet opening and closing to control the lifting of the presser foot, the utility model controls more precisely.

[0005] The present utility model achieves the above technical purpose by the following technical means.

[0006] A presser foot lifting crank drive mechanism for a sewing machine, comprising a presser foot lifting mechanism and a drive motor. The output shaft of the drive motor is connected to a drive crank, the drive crank is in transmission connection with a transmission connecting rod, there is an angle between the input section and the output section of the transmission connecting rod, the angle is an acute angle, and the output section of the transmission connecting rod is in transmission connection with the presser foot lifting mechanism.

[0007] Further, an input hole is provided on the input section of the drive crank. There is an opening at the upper part of the input hole, and the opening extends upward. Adjusting platforms are provided in parallel on both sides of the opening.

[0008] Further, the diameter of the shaft end at the input end of the drive crank is larger than the diameter of the shaft end at the output end. The input hole and the output hole are respectively provided on the two shaft ends. The input hole and the output hole are connected by an inclined surface, and both inclined surfaces are tangent to the two shaft ends. The thickness of the input end is greater than the thickness of the output end.

[0009] Further, the output section of the drive crank is hinged to a roller, the roller can roll relative to the drive crank, and the roller contacts the transmission connecting rod.

[0010] Further, the transmission connecting rod is integrally in an open trapezoidal shape and is divided into three sections. The part in transmission connection with the drive crank is the input section of the transmission connecting rod, the part in transmission connection with the presser foot lifting mechanism is the output section, and the input section and the output section are connected by an intermediate section.

[0011] Further, there is an obtuse angle between the input section of the transmission connecting rod and the intermediate section of the transmission connecting rod, and there is also an obtuse angle between the intermediate section of the transmission connecting rod and the output section of the transmission connecting rod. Among them, the angle between the input section and the intermediate section is greater than the angle between the intermediate section and the output section.

[0012] Further, no installation parts are provided on the input section and the intermediate section of the transmission connecting rod. Two installation parts are provided on the output section of the transmission connecting rod from top to bottom, namely a fixing part and a traction part.

[0013] Further, the fixing part hinges and fixes the transmission connecting rod inside the sewing machine. The traction part is hinged to one end of a pull rod, and the other end of the pull rod is hinged to the presser foot lifting mechanism.

[0014] Further, the drive motor is installed on the rear window plate of the sewing machine.

[0015] The beneficial effects of the present utility model are:

[0016] The utility model installs a driving motor and a driving mechanism assembly at the sewing machine column, shortens the length of the force arm, reduces the force received by the column, and the driving mechanism is designed with a compact structure, occupying a very small space in the already scarce internal space of the sewing machine and not interfering with other components inside the sewing machine; through a lightweight alloy rod, which has a small mass and high strength, it is connected between the driving mechanism and the presser foot lifter, and can transmit force and motion efficiently and reliably to control the lifting and lowering of the presser foot of the sewing machine; through motor drive, the height of the presser foot lifting and lowering can be precisely controlled. Compared with the traditional electromagnetic iron opening and closing to control the lifting and lowering of the presser foot, the control of the utility model is more precise. Brief Description of the Drawings

[0017] Figure 1 It is a three-dimensional structural schematic diagram of the presser foot crank driving mechanism of the sewing machine of the utility model.

[0018] Figure 2 It is a front view structural schematic diagram of the driving crank of the utility model.

[0019] Figure 3 It is a side view structural schematic diagram of the driving crank of the utility model.

[0020] Figure 4 It is a front view structural schematic diagram of the transmission connecting rod of the utility model.

[0021] Figure 5 It is a front view assembly structural schematic diagram of the presser foot crank driving mechanism of the sewing machine of the utility model.

[0022] In the figure, 1-sewing machine rear window plate, 2-driving motor, 3-driving crank, 31-input hole, 32-adjusting table, 33-output hole, 34-adjusting hole, 4-transmission connecting rod, 41-input section, 42-middle section, 43-output section, 44-fixing part, 45-traction part, 5-presser foot mechanism, 6-roller, 7-pull rod. Detailed Description of the Preferred Embodiment

[0023] The following further illustrates the utility model in conjunction with the drawings and specific embodiments, but the protection scope of the utility model is not limited thereto.

[0024] Embodiment:

[0025] As Figures 1 to 4 shown, the driving motor 2 is the main power source of the mechanism. It is not only the power core of the whole mechanism but also the key factor to ensure the precision and efficiency of the sewing process. Its stability and efficiency directly determine the accuracy and smoothness of the presser foot movement, and thus affect the sewing quality.

[0026] In terms of design, the drive motor 2 is ingeniously installed on the rear window panel 1 of the sewing machine. Such a layout has several remarkable advantages. Firstly, since the motor is installed on the outside of the sewing machine, there are no strict restrictions on the size of the motor, and a motor with a higher power or better performance can be selected to meet the requirements of different sewing tasks. This flexibility makes it possible to improve the performance of the sewing machine.

[0027] The drive motor 2 is positioned on the side close to the sewing machine column. Such a layout is extremely beneficial for the normal operation of the sewing machine and the user experience of the operator. The installation of the motor does not interfere with the thread feeding system of the sewing machine, ensuring smooth and accurate thread feeding. At the same time, such an installation position does not block the view of the textile worker, ensuring that the operator can have a good line of sight during the sewing process, thereby improving work efficiency and sewing quality.

[0028] In addition, installing the drive motor 2 on the side close to the column helps to shorten the length of the lever arm, thereby reducing the force exerted on the column. The lever arm is the distance from the fulcrum to the line of action of the force. By shortening the lever arm, the force required to generate the same torque can be reduced. This not only lightens the burden on the column but also improves the stability and efficiency of the entire system. This design also helps to improve the mechanical efficiency of the sewing machine because it reduces the losses during the force transmission process.

[0029] The output shaft of the drive motor 2 passes through the rear window panel 1 of the sewing machine and enters the interior of the sewing machine. Such a design enables the output of the motor to be directly transmitted to the key components of the sewing machine, ensuring the high efficiency and accuracy of power transmission. At the same time, this layout is also convenient for maintenance and possible upgrades because the position of the motor is easily accessible, and the connection between the output shaft of the motor and the internal mechanical components is relatively simple.

[0030] Installing the drive motor 2 on the side close to the column also facilitates the automation upgrade of the sewing machine. There is enough space above the motor to install additional controllers or other automation devices, making it possible to automate the sewing machine. Although the automation of the sewing machine is not an innovation point of this utility model, this design undoubtedly provides convenience for possible future automation upgrades.

[0031] One end of the output shaft of the drive motor 2 located inside the sewing machine is connected to the input hole 31 provided at the shaft end of the input section of the drive crank 3. Since the input hole 31 adopts a semi-open design, within a certain range, the input hole 31 can adapt to the output shafts of drive motors 2 with different diameters. At the same time, both sides of the opening of the output hole 31 are appropriately extended upwards, extending out the adjusting table 32 component structure. There is an opening between the two adjusting tables 32, and the end faces of the two adjusting tables 32 close to the opening are parallel to each other. Such a design allows for more adjustment space during connection and also facilitates maintenance and inspection work.

[0032] Concentric through holes, namely adjusting holes 34, are provided on the side end faces of the two adjusting tables 32. The adjusting holes 34 are used to fixedly connect the output shaft of the drive motor 2 and the input hole 31 of the drive crank 3. Ensure that when the output shaft of the drive motor 2 rotates, it can transfer torque to the entire drive crank 3 through the input hole 31 of the drive crank 3, thereby driving the drive crank 3 and the output shaft of the drive motor 2 to rotate synchronously, and there will be no slipping phenomenon of the output shaft of the drive motor 2 inside the drive crank 3.

[0033] When connecting the drive motor 2 to the drive crank 3 in the crank - connecting rod mechanism as the drive structure, first insert the motor output shaft of the drive motor 2 into the input hole 31 of the drive crank 3. Among them, it should be noted that the aperture gap between the output shaft of the drive motor 2 and the input hole 31 of the drive crank 3 cannot be too large, otherwise, even if the end faces of the two adjusting tables 32 are completely fitted, they cannot be locked and matched.

[0034] Therefore, for the case where the aperture gap between the output shaft of the drive motor 2 and the input hole 31 of the drive crank 3 is too large, a shaft sleeve can be fixedly inserted into the output shaft of the drive motor 2. The inner hole diameter of the shaft sleeve should be adapted to the shaft diameter of the output shaft of the drive motor 2, and the outer diameter of the shaft sleeve should be adapted to the aperture of the input hole 31 of the drive crank 3. In this way, the output shaft of the drive motor 2 and the input hole 31 of the drive crank 3 can also be locked and installed to achieve synchronous rotation of the output shaft of the drive motor 2 and the input hole 31 of the drive crank 3.

[0035] The input hole 31 of the drive crank 3 is provided at the shaft end of the input section of the drive crank 3, and an output hole 33 of the drive crank 3 is provided at the shaft end of the output section of the drive crank 3. The input hole 31 and the output hole 33 of the drive crank 3 are connected by inclined planes on both sides. Both inclined planes are tangent to the arc at the shaft end of the input section of the drive crank 3 and tangent to the arc at the shaft end of the output section of the drive crank 3 at the same time.

[0036] Meanwhile, since it is directly connected to the output shaft of the drive motor 2, comparatively speaking, the torque received by the input hole of the drive crank 3 is greater than that received by other components of the crank-link mechanism. Therefore, the thickness of the shaft end of the input section of the drive crank 3 is thicker than that of the shaft end of the output section of the drive crank 3. The thickness of the shaft end of the input section of the drive crank 3 is 2 to 2.5 times the thickness of other parts of the drive crank 3. The input section and the output section of the drive crank 3 are on the side away from the drive motor 2, and the end faces of this side of the input section and the output section of the drive crank 3 are coplanar, that is, located on the same plane.

[0037] In order to reduce the friction during the transmission process, the output hole 33 of the drive crank 3 is not directly connected to the transmission connecting rod for transmission. Instead, a roller 6 is connected and installed at the output hole 33 of the drive crank 3, and the transmission of the drive crank 3 is realized through the roller 6. The roller 6 is cylindrical, and a connecting hole matching the aperture of the output hole 33 of the drive crank 3 is provided at the center of the roller 6. The roller 6 and the output hole 33 of the drive crank 3 are hinged, and relative rotation can occur between the roller 6 and the output hole 33 of the drive crank 3.

[0038] Due to the limitations of the internal structure of the sewing machine, and the crank-link mechanism will generate frequent friction and transmission inside the sewing machine. However, the transmission between the roller 6 and the transmission connecting rod 4 is an open transmission, the connection relationship between the mechanisms is not closed enough, the lubrication conditions are limited, and the roller 6 is not the main force-bearing component in the entire crank-link mechanism. Therefore, some materials with excellent self-lubricating properties, such as brass, can be used for the material selection of the roller 6. It can further reduce the friction while the roller 6 undergoes rolling friction during the rolling contact in the case of a lack of good lubrication conditions inside the sewing machine, reduce the heat generation of the mechanism, improve the output efficiency of the drive motor 2, improve the energy utilization rate, reduce the wear of important components in the crank-link mechanism, protect the transmission connecting rod 4, and extend the service life of the transmission connecting rod 4 and the drive crank 3.

[0039] The transmission connecting rod 4 is a key component connecting the driving crank 3 and the presser foot lifting mechanism. The transmission connecting rod 4 can be divided into three functional segments, namely the input segment 41, the intermediate segment 42, and the output segment 43. The overall configuration of the transmission connecting rod 4 can be regarded as an open trapezoidal structural configuration, and the outer shape of the transmission connecting rod 4 can also be regarded as being similar to a boomerang. Among them, the included angle between the input segment 41 of the transmission connecting rod 4 and the output segment 43 of the transmission connecting rod 4 is an acute angle, but the included angle between the input segment 41 of the transmission connecting rod 4 and the intermediate segment 42 of the transmission connecting rod 4 is an obtuse angle, and the angle range is between 130° and 170°. The included angle between the intermediate segment 42 of the transmission connecting rod 4 and the output segment 43 of the transmission connecting rod is an obtuse angle, and the angle range is between 95° and 110°. The angle of the included angle between the input segment 41 of the transmission connecting rod 4 and the intermediate segment 42 of the transmission connecting rod 4 is greater than the degree of the included angle between the intermediate segment 42 of the transmission connecting rod 4 and the output segment 43 of the transmission connecting rod 4.

[0040] On the transmission connecting rod 4, its input segment 41 is strip-shaped, and no holes, grooves, or protruding structures for connecting and installing with other components are provided on the input segment 41 of the transmission connecting rod 4. The lower end surface of the input segment 41 of the transmission connecting rod 4 is responsible for contacting the roller 6, and the roller 6 will rotate together with the rotation of the driving crank 3, thereby raising the input segment 41 of the transmission connecting rod 4. Therefore, the roller 6 will make contact on the lower end surface of the input segment 41 of the transmission connecting rod 4. The roller 6 is hinged with the output hole 33 of the driving crank 3. Therefore, the roller 6 can rotate relative to the output hole 33 of the driving crank 3. Further, rolling can also occur on the contact end surface between the roller 6 and the lower end of the input segment 41 of the transmission connecting rod 4.

[0041] A contact connection is adopted between the roller 6 and the transmission connecting rod 4, rather than the shaft-hole mating connection of the conventional crank connecting rod mechanism. Adopting such a connection method can effectively protect the transmission connecting rod 4 and the pull rod 7, and the limit position of the transmission connecting rod 4 and the rotation range of the driving crank 3 can be inconsistent. The precision requirement for the movement cooperation is not so high, and it is not easy to occur that after the movement range of the driving crank 3 exceeds the movement limit range of the transmission connecting rod 4, the transmission connecting rod 4 is forcibly driven, resulting in damage to the entire crank connecting rod mechanism, and even damage to the internal components and the main shaft of the sewing machine.

[0042] The input segment 41 of the transmission connecting rod 4 is connected to the intermediate segment 42. The intermediate segment 42 of the transmission connecting rod 4 is a transition segment in the transmission connecting rod 4, which makes the force transmitted by the driving crank 3 more evenly distributed, and at the same time ensures that the force transmitted from the input segment 41 of the transmission connecting rod 4 to the output segment 43 is smoother. The transmission connecting rod 4 also adopts the lever principle. Therefore, the intermediate segment 42 also plays a role in extending the length of the force arm of the input segment 41 of the transmission connecting rod 4, enabling the output segment of the transmission connecting rod 4 to generate a greater pulling force on the pull rod 7, thereby generating a greater pulling force on the presser foot lifting mechanism 5 of the sewing machine and driving the lifting of the presser foot lifting mechanism 5 of the sewing machine.

[0043] Since the drive link 4 adopts the lever principle, a fulcrum for supporting the lever needs to be provided on the output section 43 of the drive link 4. On the output section of the drive link 4, two holes are provided from top to bottom. The upper hole is the fixing part 44, and the lower hole is the traction part 45. The aperture of the fixing part 44 is larger than that of the traction part 45. The fixing part 44 of the drive link 4 is used to install the drive link 4 on the sewing machine, but at the same time does not affect the rotation of the drive link 4 relative to the sewing machine. Therefore, the installation method of the fixing part 44 of the drive link 4 adopts hinge connection. The coordinate position of the fixing part 44 of the drive link 4 does not change, so the fixing part 44 of the drive link 4 serves as the fulcrum when the drive link 4 rotates. The traction part of the drive link 4 is hinged to the pull rod 7 and is responsible for transmitting the force transmitted by the drive crank 3 and pulling the pull rod 7 backward.

[0044] Before describing the working process of the sewing machine presser foot lifting crank drive mechanism, for the sake of easy understanding, the movement that controls the lifting of the presser foot mechanism 5 is set to be generated when the motor rotates forward, and the movement that the presser foot mechanism 5 drops is set to be generated when the motor rotates backward.

[0045] As Figure 5 shown, when the sewing machine starts to work and it is necessary to feed the cloth in and lift the presser foot mechanism 5, the output shaft of the drive motor 2 rotates forward, driving the output section of the drive crank 3 to rotate clockwise, and the control roller 6 also rotates clockwise around the input hole 31 of the drive crank 3. The roller 6 pushes up the input section 41 of the drive link 4, and the drive link 4 starts to rotate clockwise around the fixing part 44 of the drive link. The output section 43 of the drive link 4 rotates clockwise accordingly. At this time, one end of the pull rod 7 connected to the traction part 45 of the drive link 4 is pulled to the left, pulling the sewing machine presser foot mechanism 5 upward.

[0046] When the cloth is sent to the specified position and it is necessary to control the lowering of the sewing machine presser foot mechanism 5, the motor is reversed at this time. The drive crank 3 rotates counterclockwise from the high position to the low position. Correspondingly, the sewing machine presser foot mechanism 5 will also naturally drop under the action of gravity, pulling the pull rod 7 to the right, thereby driving the drive link 4 to rotate counterclockwise until the lower end face of the drive link 4 abuts against the roller 6.

[0047] Since the rotation of the drive crank 3 is controlled by the drive motor 2, the rotation angle of the drive crank 3 can be accurately controlled, and the lifting height of the presser foot mechanism 5 can also be relatively accurately controlled. For different fabrics, the length to be fed in can also be better controlled, rather than only having two states of lifting and lowering like the presser foot controlled by an electromagnet, and it can adapt to more complex sewing requirements.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A presser foot lifting crank drive mechanism for a sewing machine, comprising a presser foot lifting mechanism (5) and a drive motor (2), characterized in that, The output shaft of the driving motor (2) is connected to the driving crank (3), the driving crank (3) is in transmission connection with the transmission connecting rod (4), an included angle exists between the input section (41) and the output section (43) of the transmission connecting rod (4), the included angle is an acute angle, and the output section of the transmission connecting rod (4) is in transmission connection with the presser foot lifting mechanism (5).

2. The presser foot lifting crank drive mechanism of the sewing machine according to claim 1, wherein An input hole (31) is provided on the input section of the driving crank (3), an opening exists in the upper part of the input hole (31), and adjusting platforms (32) are arranged in parallel on both sides of the opening extending upward.

3. The presser foot lifting and lowering crank drive mechanism of a sewing machine according to claim 2, characterized in that, The diameter of the shaft end of the input end of the driving crank (3) is larger than that of the shaft end of the output end. The input hole (31) and the output hole (33) are respectively provided on the two shaft ends. The input hole (31) and the output hole (33) are connected by an inclined surface, and both sides of the inclined surface are tangent to the shaft ends of the connecting section. The thickness of the input end is larger than that of the output end.

4. The sewing machine presser foot lifting crank drive mechanism according to claim 1 or 2 or 3, characterized in that, The output section of the driving crank (3) is hinged to a roller (6), the roller (6) can roll relative to the driving crank (3), and the roller (6) contacts the transmission connecting rod (4).

5. The presser foot lifting and lowering crank drive mechanism of a sewing machine according to claim 1, characterized in that, The transmission connecting rod (4) is integrally in an open trapezoidal shape and is divided into three sections. The part in transmission connection with the driving crank (3) is the input section (41) of the transmission connecting rod (4), the part in transmission connection with the presser foot lifting mechanism (5) is the output section (43), and the input section (41) and the output section (43) are connected by an intermediate section (42).

6. The sewing machine presser foot lifting crank drive mechanism according to claim 1 or 2 or 3 or 5, characterized in that, An included angle exists between the input section (41) and the intermediate section (42) of the transmission connecting rod (4), and the included angle is an obtuse angle. An obtuse included angle also exists between the intermediate section (42) and the output section (43) of the transmission connecting rod (4), and the included angle between the input section (41) and the intermediate section (42) is larger than the included angle between the intermediate section (42) and the output section (43).

7. The presser foot lifting and lowering crank drive mechanism of a sewing machine according to claim 1 or 2 or 3 or 5, characterized in that, No mounting parts are provided on the input section (41) and the intermediate section (42) of the transmission connecting rod (4). Two mounting parts are provided on the output section (43) of the transmission connecting rod (4) from top to bottom, namely a fixing part (44) and a traction part (45).

8. The presser foot lifting crank drive mechanism of a sewing machine according to claim 7, characterized in that, The fixing part (44) hingedly fixes the transmission connecting rod (4) inside the sewing machine. The traction part (45) is hinged to one end of a pull rod (7), and the other end of the pull rod (7) is hinged to the presser foot lifting mechanism (5).

9. The presser foot lifting crank drive mechanism of a sewing machine according to claim 1 or 2 or 3 or 5 or 8, characterized in that, The driving motor (2) is installed on the rear window plate (1) of the sewing machine.

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