Multi-shaft transmission granule printer lifting mechanism

Abstract

The invention discloses a multi-shaft transmission granule printer lifting mechanism, which comprises a printer main body, and comprises a bottom frame, the top of which is fixedly connected with a plurality of groups of vertical pipes; the top frame is fixedly connected to the tops of the vertical pipes; the four groups of lifting mechanisms are arranged between the bottom frame and the top frame in a regular matrix; two groups of platform mounting racks, wherein each group of platform mounting rack is connected with two groups of lifting mechanisms; the bottom frame, the vertical pipes and the top frame form a stable frame structure, the four sets of lifting mechanisms are arranged between the bottom frame and the top frame in a regular matrix mode, the two sets of platform mounting frames are connected with the printing platform, and through the symmetrical mechanical structure design, the printing platform can be evenly stressed in the lifting process; no matter bearing the weight of a large printing model or in frequent lifting operation, the platform can be effectively prevented from inclining, shaking and other unstable conditions, and reliable structural guarantee is provided for stable operation of the large particle printer.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, specifically to a lifting mechanism for a multi-axis driven pellet printer. Background Technology

[0002] In the field of large-format particle printers, existing lifting mechanisms are mostly simple single-axis drive or a few-axis coordinated drive mode. Due to their large printing size and heavy load, large-format particle printers place extremely high demands on the stability and synchronization of the lifting mechanism. Single-axis drive lifting mechanisms can only achieve the lifting operation of a single printing platform, proving inadequate for the needs of multiple printing platforms working collaboratively in large printing jobs, or for complex printing jobs with stringent requirements for platform flatness and synchronization. While the few-axis coordinated drive mode improves upon the shortcomings of single-axis drive to some extent, there is still significant room for improvement in the accuracy and stability of multi-axis transmission when dealing with the heavy-duty conditions of large printers. During printing, the lifting action of the printing platform needs to be closely coordinated with the working rhythm of the printhead. If the lifting mechanism is unresponsive or its movement is unstable, it will directly affect the quality of the printed product, leading to problems such as interlayer misalignment and uneven surface. Furthermore, existing lifting mechanisms are relatively simple in structural design and lack special protective designs for the working environment of large printers, making it difficult to effectively deal with issues such as particle dust generated during printing.

[0003] Specifically, existing lifting mechanisms have several shortcomings. First, it is difficult to ensure the synchronization of multiple printing platforms during the lifting process. The height difference between platforms can cause defects at the joints of large and complex printed models, affecting print quality and accuracy. Second, due to unreasonable structural design, existing lifting mechanisms are prone to wear and jamming under long-term heavy-duty operation, shortening the equipment's lifespan and increasing maintenance costs. Third, the particulate dust generated during the operation of large granular printers, as well as the large printing area, make it difficult for existing lifting mechanisms to effectively seal, resulting in insufficient dust prevention capabilities. External impurities can easily interfere with the printing process, reducing the quality of printed products.

[0004] Given the numerous shortcomings of the existing technologies, there is an urgent need for a new multi-axis drive lifting mechanism for granulation printers to provide a reliable guarantee for the stable and efficient operation of large granulation printers. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-axis driven lifting mechanism for a granule printer, so as to solve the problems existing in the current large granule printers mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a multi-axis driven granule printer lifting mechanism, comprising a printer body, including: The base frame has several sets of vertical pipes fixedly connected to its top; The top frame is fixedly connected to the top of several sets of the vertical pipes; Four sets of lifting mechanisms are arranged in a regular matrix between the base frame and the top frame; Two sets of platform mounting frames, each set of platform mounting frames is connected to two sets of lifting mechanisms, and a printing platform is connected to the top of the two sets of platform mounting frames; The main drive mechanism is mounted on the base frame; A drive belt connects the main drive mechanism to the four sets of lifting mechanisms; The lifting mechanism includes: Two sets of optical axis fixing seats are respectively fixed to the top of the base frame and the bottom of the top frame by bolts; The optical axis is fixed between the two sets of optical axis fixing seats, and the optical axis is fitted through the platform mounting frame with clearance fit. Two sets of screw support seats are respectively fixed to the top of the base frame and the bottom of the top frame by bolts; A ball screw is fixed between two sets of screw support seats, and the ball screw is connected to the platform mounting frame through a threaded structure. A protective frame is fixed to the top of the base frame, and the protective frame covers the outside of one set of the lead screw support seats; The driven wheel is fixed to the outer side of the lower end of the ball screw; The main drive mechanism drives four sets of lifting mechanisms via a transmission belt, so that the two sets of platform mounting frames and the printing platform can be raised and lowered.

[0007] Preferably, the lifting mechanism further includes four sets of dust covers, two of which are fitted onto the outside of the optical axis, and the other two are fitted onto the outside of the ball screw. The four sets of dust covers are fixed in pairs to the upper and lower sides of the platform mounting frame.

[0008] Preferably, the lifting mechanism further includes: An upper limit post is fixed to the bottom of the top frame; The lower limit post is fixed to the top of the base frame; The platform mounting frame is connected to the upper limit post and the lower limit post respectively by lifting.

[0009] Preferably, the main drive mechanism includes: The motor housing is fixed to the top of the base frame; A servo motor is installed inside the motor housing; The drive wheel is fixedly connected to the motor shaft of the servo motor; The first bracket, the two sets of second brackets, and the third bracket are all fixedly connected to the top of the base; Two sets of first tensioning rollers are rotatably mounted on the top of the first bracket via bearings; Four sets of second tensioning rollers are rotatably mounted on top of two sets of second brackets via bearings; Two sets of anti-deviation wheels are rotatably mounted on the top of the third bracket via bearings.

[0010] Preferably, the transmission belt is connected to four sets of driven pulleys, two sets of first tension pulleys, four sets of second tension pulleys, and two sets of anti-deviation pulleys.

[0011] Compared with the prior art, the beneficial effects of the present invention are: 1) This application uses a base frame, vertical tubes and top frame to form a stable frame structure, which lays a solid foundation for the entire lifting system. Four sets of lifting mechanisms are arranged in a regular matrix between the base frame and the top frame, and are connected to the printing platform through two sets of platform mounting frames. This symmetrical mechanical structure design can make the printing platform evenly stressed during the lifting process. Whether it is bearing the weight of a large printing model or in frequent lifting operations, it can effectively avoid the platform from tilting, shaking and other unstable situations, and provide a reliable structural guarantee for the stable operation of large granular material printers. 2) This application provides precise guidance for the lifting and lowering movement of the platform, enabling it to run smoothly along a predetermined straight trajectory, effectively reducing deviations during the movement. The ball screw and screw support are closely matched, and with its high-precision thread structure, the rotational motion transmitted by the main drive mechanism is efficiently and accurately converted into the linear lifting and lowering motion of the platform mounting frame. This transmission method not only has high transmission efficiency but also excellent positioning accuracy, which can precisely control the lifting and lowering height of the printing platform and meet the extremely high requirements of printing accuracy for large and complex granular material printing models. 3) This application effectively protects the bottom lead screw support seat with a protective frame, effectively isolating external debris and other impurities. Four sets of dust covers are respectively fitted on the outside of the optical shaft and ball screw and are tightly fixed to the platform mounting frame. During the movement of the optical shaft and ball screw, they are continuously wrapped to further prevent dust from adhering and ensure the clean operation of the transmission components. The tension wheel and anti-deviation wheel in the main drive mechanism work together. The tension wheel adjusts the tension of the transmission belt to ensure that the belt will not slip during power transmission, while the anti-deviation wheel constantly corrects the belt's running trajectory to prevent it from deviating. This ensures that the four lifting mechanisms can operate synchronously and stably. In addition, the double limit protection of the upper limit column and the lower limit column can prevent the printing platform from excessively lifting and lowering, thus comprehensively improving the reliability and safety of the lifting mechanism. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this application; Figure 2 This is a schematic diagram of the structure after the platform frame is dismantled and installed according to this application; Figure 3 This is a partial structural diagram of this application; Figure 4 This is a schematic diagram of another partial structure of this application; Figure 5 This is a schematic diagram showing the location of the protective frame in this application; Figure 6 This is a schematic diagram showing the location of the motor housing in this application.

[0013] In the picture: 1. Base frame; 2. Vertical tube; 3. Top frame; 4. Lifting mechanism; 401. Optical axis fixing seat; 402. Optical axis; 403. Screw support seat; 404. Ball screw; 405. Protective frame; 406. Driven wheel; 407. Dust cover; 408. Upper limit post; 409. Lower limit post; 5. Platform mounting frame; 6. Main drive mechanism; 601. Motor housing; 602. Servo motor; 603. Drive wheel; 604. First bracket; 605. Second bracket; 606. Third bracket; 607. First tension wheel; 608. Second tension wheel; 609. Anti-deviation wheel; 7. Drive belt; 8. Printing platform. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] In the description of the invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0016] In the description of the invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0017] Please see Figure 1-6 This invention provides a technical solution: a multi-axis driven lifting mechanism for a granule printer, comprising a printer body, including: The base frame 1 has several sets of vertical pipes 2 fixedly connected to its top; Top frame 3 is fixedly connected to the top of several sets of vertical pipes 2; Four sets of lifting mechanisms 4 are arranged in a regular matrix between the base frame 1 and the top frame 3; Two sets of platform mounting frames 5, each set of platform mounting frames 5 is connected to two sets of lifting mechanisms 4, and a printing platform 8 is connected to the top of the two sets of platform mounting frames 5; The main drive mechanism 6 is mounted on the base frame 1; The drive belt 7 is connected to the main drive mechanism 6 and the four sets of lifting mechanisms 4; The lifting mechanism 4 includes: Two sets of optical axis fixing seats 401 are respectively fixed to the top of the base frame 1 and the bottom of the top frame 3 by bolts; The optical axis 402 is fixed between two sets of optical axis fixing seats 401, and the optical axis 402 is fitted through the platform mounting frame 5 with clearance fit. Two sets of screw support seats 403 are fixed to the top of the base frame 1 and the bottom of the top frame 3 by bolts, respectively; The ball screw 404 is fixed between two sets of screw support seats 403, and the ball screw 404 is connected to the platform mounting frame 5 through a threaded structure. The protective frame 405 is fixed to the top of the base frame 1, and the protective frame 405 covers the outside of one set of screw support seats 403; The driven wheel 406 is fixed to the outer side of the lower end of the ball screw 404; The main drive mechanism 6 drives four sets of lifting mechanisms 4 through the transmission belt 7, so that the two sets of platform mounting frames 5 and the printing platform 8 are raised and lowered.

[0018] Specifically, the base frame 1, several sets of vertical pipes 2, and the top frame 3 constitute a stable frame structure, providing a solid and reliable installation foundation for the entire lifting mechanism. Four sets of lifting mechanisms 4 are arranged in a regular matrix between the base frame 1 and the top frame 3. Two sets of platform mounting frames 5 are connected to the two sets of lifting mechanisms 4 respectively, with the top supporting the printing platform 8. This layout ensures that the printing platform 8 is subjected to uniform force during lifting, greatly improving stability and effectively preventing tilting or swaying caused by uneven force, thus guaranteeing high-quality printing operations.

[0019] Specifically, the main drive mechanism 6 is mounted on the base frame 1 and connected to four lifting mechanisms 4 via a transmission belt 7 to achieve efficient power transmission. The optical shaft fixing seat 401 in the lifting mechanism 4 fixes the optical shaft 402, which is fitted with a clearance fit inside the platform mounting frame 5, providing precise guidance and ensuring that the platform mounting frame 5 moves along a predetermined straight trajectory during lifting. The ball screw 404 is fixed by the screw support seat 403 and connected to the platform mounting frame 5 via a threaded structure, accurately converting rotational motion into linear lifting motion, improving lifting accuracy and transmission efficiency. The protective frame 405 covers the outside of the screw support seat 403, effectively protecting its internal components, extending service life, and reducing maintenance costs. The driven wheel 406 is fixed to the outer side of the lower end of the ball screw 404, facilitating power transmission with the transmission belt 7 and ensuring synchronous operation of the four lifting mechanisms 4, thereby achieving smooth and precise lifting of the printing platform 8.

[0020] Reference manual attached Figure 1-3 The lifting mechanism 4 also includes four sets of dust covers 407, two of which are fitted on the outside of the optical axis 402, and the other two are fitted on the outside of the ball screw 404. The four sets of dust covers 407 are fixed in pairs on the upper and lower sides of the platform mounting frame 5.

[0021] Specifically, the four sets of dust covers 407 further enhance the protective performance. During the movement of the optical shaft 402 and the ball screw 404, the dust covers 407 always maintain a protective state around the position close to the platform mounting frame 5, effectively preventing dust, debris, and other impurities from adhering to the surface of the optical shaft 402 and the ball screw 404, avoiding the impact of impurity accumulation on transmission accuracy and normal equipment operation. This not only reduces wear on the threaded connections between the optical shaft 402 and the platform mounting frame 5, and between the ball screw 404 and the platform mounting frame 5, extending the service life of the optical shaft 402, the ball screw 404, and the platform mounting frame 5, but also ensures the long-term stable operation of the lifting mechanism 4, improves the reliability of the entire granule printer lifting mechanism, and ensures that the stability and accuracy of the printing platform 8 during the lifting process are not affected by external impurities.

[0022] Reference manual attached Figure 1-2 The lifting mechanism 4 also includes: The upper limit post 408 is fixed to the bottom of the top frame 3; The lower limit post 409 is fixed to the top of the base frame 1; The platform mounting frame 5 is connected to the upper limit post 408 and the lower limit post 409 respectively by lifting.

[0023] Specifically, when the platform mounting bracket 5 rises to contact the upper limit post 408 or descends to contact the lower limit post 409 during the lifting and lowering process, it can promptly limit the continued movement of the platform mounting bracket 5. This effectively prevents excessive lifting and lowering of the printing platform 8 due to control errors, equipment malfunctions, or other reasons, avoids collisions between the printing platform 8 and other printer components, prevents equipment damage, and ensures the safety of equipment operation. At the same time, the setting of the upper and lower limit posts also provides a clear definition of the lifting and lowering range of the printing platform 8, which helps to improve the standardization and accuracy of the printing process and ensures that printing operations are carried out within a safe and controllable range.

[0024] Reference manual attached Figure 2 Instruction manual attached Figure 4 and instruction manual attached Figure 6 The main drive mechanism 6 includes: The motor housing 601 is fixed to the top of the base frame 1; Servo motor 602 is installed inside motor housing 601; The drive wheel 603 is fixedly connected to the motor shaft of the servo motor 602; The first bracket 604, the two sets of second brackets 605 and the third bracket 606 are all fixedly connected to the top of the base 1; Two sets of first tensioning rollers 607 are rotatably mounted on the top of the first bracket 604 via bearings; The four sets of second tensioning rollers 608 are rotatably mounted on the top of the two sets of second brackets 605 via bearings; Two sets of anti-deviation wheels 609 are rotatably mounted on the top of the third bracket 606 via bearings.

[0025] Specifically, the motor housing 601 is fixed to the top of the base frame 1, protecting the servo motor 602 and reducing the impact of external environmental factors such as dust and moisture on the servo motor 602, thus improving its operational stability and service life. The servo motor 602 drives the drive wheel 603 to rotate, transmitting power to the driven wheels 406 of the four lifting mechanisms 4 via the transmission belt 7, achieving efficient power transmission. The first bracket 604, two sets of second brackets 605, and the third bracket 606 are fixedly connected to the top of the base 1, and respectively install two sets of first tensioning wheels 607, four sets of second tensioning wheels 608, and two sets of anti-deviation wheels 609. The tensioning wheels can adjust the tension of the transmission belt 7 in real time, ensuring that the transmission belt 7 maintains appropriate tension during transmission, avoiding slippage, and improving transmission efficiency and stability; the anti-deviation wheels can effectively prevent the transmission belt 7 from deviating during operation, ensuring transmission accuracy, thereby ensuring that the four lifting mechanisms 4 can operate synchronously and stably, achieving smooth and precise lifting operations of the printing platform 8.

[0026] Reference manual attached Figure 3-4 The drive belt 7 is connected to four sets of driven pulleys 406, two sets of first tension pulleys 607, four sets of second tension pulleys 608, and two sets of anti-deviation pulleys 609. Specifically, this transmission layout allows the power of the main drive mechanism 6 to be transmitted evenly and stably to the four lifting mechanisms 4. The tension adjustment of the drive belt 7 by the first tension pulleys 607 and second tension pulleys 608 ensures that the drive belt 7 maintains good transmission performance under different working conditions, avoiding power transmission loss and slippage caused by belt slack, thus improving transmission efficiency. The anti-deviation pulleys 609 ensure that the drive belt 7 always runs along the correct trajectory, preventing belt deviation from affecting the stability and accuracy of power transmission. The four sets of driven pulleys 406 are connected to the ball screws 404, which can accurately convert the power transmitted by the drive belt 7 into the lifting motion of the printing platform 8, ensuring the synchronous operation of the four lifting mechanisms 4, thereby achieving smooth and precise lifting of the printing platform 8, meeting the high precision and high stability requirements of large granular material printers for the lifting motion of the printing platform.

[0027] Specifically, the motor housing 601 can be fixed to the base frame 1 by bolts and can be fixed in different positions. When it is necessary to adjust the tension of the transmission belt 7, the bolts fixing the motor housing 601 can be loosened, allowing the motor housing 601 to be adjusted in position on the base frame 1. Since the servo motor 602 is fixed inside the motor housing 601, as the position of the motor housing 601 changes, the position of the drive pulley 603 driven by the servo motor 602 also changes accordingly. If the transmission belt 7 is further stretched, the tension will increase; conversely, the tension of the transmission belt 7 can be reduced. During the adjustment process, the fine-tuning action of the first tensioning pulley 607 and the second tensioning pulley 608 on the transmission belt 7 can more accurately adjust the transmission belt 7 to a suitable tension state. After adjustment, tighten the bolts securing the motor housing 601 to fix its position, ensuring that the transmission belt 7 maintains a stable tension during equipment operation. This effectively prevents slippage caused by an overly loose belt or excessive wear of components due to an overly tight belt, ensuring the stability and efficiency of power transmission. Consequently, it ensures that the four lifting mechanisms 4 can operate synchronously and stably, enabling smooth and precise lifting operations of the printing platform 8.

[0028] During operation, after the device is started, the servo motor 602 is powered on and runs. Its motor shaft drives the drive wheel 603 to rotate. The drive wheel 603 serves as the starting point of the power for the entire transmission system, transmitting the rotational power of the servo motor 602. The drive wheel 603 is connected to the driven wheel 406 in the four lifting mechanisms 4 via the transmission belt 7. The transmission belt 7 drives the driven wheel 406 to rotate, thus rotating the ball screw 404. When the ball screw 404 rotates, due to the action of the thread, the platform mounting frame 5 will move linearly along the ball screw 404. At the same time, the optical shaft 402 provides guidance for the linear movement of the platform mounting frame 5, ensuring that the platform mounting frame 5 runs smoothly along the predetermined linear trajectory during the lifting process, avoiding deviation or shaking. The two sets of platform mounting frames 5 are connected to the two sets of lifting mechanisms 4 respectively, and the top supports the printing platform 8. As the platform mounting frames 5 in the four lifting mechanisms 4 move linearly and vertically in sync, the printing platform 8 also rises or falls accordingly. Before the printing job begins, the printing platform 8 can be raised and lowered to a suitable initial height by the servo motor 602 according to the printing requirements. During the printing process, after one layer is printed, the printing platform 8 can descend to a certain height according to a preset program so that the print head can start the next layer printing job, achieving the purpose of printing layer by layer. When the platform mounting frame 5 rises to contact the upper limit post 408 or descends to contact the lower limit post 409 during the lifting and lowering process, the limit mechanism will be triggered to prevent the platform mounting frame 5 from continuing to move, preventing the printing platform 8 from colliding with other parts of the printer due to excessive lifting and lowering, and ensuring the safe operation of the equipment.

[0029] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lifting mechanism for a multi-axis driven granulator printer, comprising a printer body, characterized in that, include: The base frame (1) has several sets of vertical pipes (2) fixedly connected to its top. The top frame (3) is fixedly connected to the top of several sets of the vertical pipes (2); Four sets of lifting mechanisms (4) are arranged in a regular matrix between the base frame (1) and the top frame (3); Two sets of platform mounting frames (5), each set of platform mounting frames (5) is connected to two sets of lifting mechanisms (4), and a printing platform (8) is connected to the top of the two sets of platform mounting frames (5). The main drive mechanism (6) is mounted on the base frame (1); A transmission belt (7) is connected to the main drive mechanism (6) and the four sets of lifting mechanisms (4); The lifting mechanism (4) includes: Two sets of optical axis fixing seats (401) are respectively fixed to the top of the base frame (1) and the bottom of the top frame (3) by bolts; The optical axis (402) is fixed between the two sets of optical axis fixing seats (401), and the optical axis (402) is passed through the platform mounting frame (5) with clearance fit; Two sets of screw support seats (403) are respectively fixed to the top of the base frame (1) and the bottom of the top frame (3) by bolts; A ball screw (404) is fixed between two sets of screw support seats (403), and the ball screw (404) is connected to the platform mounting frame (5) through a threaded structure; A protective frame (405) is fixed to the top of the base frame (1), and the protective frame (405) covers the outside of one of the sets of screw support seats (403); The passive wheel (406) is fixed to the outer side of the lower end of the ball screw (404); The main drive mechanism (6) drives four sets of lifting mechanisms (4) via a transmission belt (7) to raise and lower the two sets of platform mounting frames (5) and the printing platform (8).

2. The multi-axis drive granulator printer lifting mechanism according to claim 1, characterized in that, The lifting mechanism (4) also includes four sets of dust covers (407), two of which are fitted on the outside of the optical axis (402), and the other two are fitted on the outside of the ball screw (404). The four sets of dust covers (407) are fixed to the upper and lower sides of the platform mounting frame (5) in pairs.

3. The multi-axis drive granulator printer lifting mechanism according to claim 1, characterized in that, The lifting mechanism (4) also includes: The upper limit post (408) is fixed to the bottom of the top frame (3); The lower limit post (409) is fixed to the top of the base frame (1); The platform mounting frame (5) is connected to the upper limit post (408) and the lower limit post (409) respectively by lifting.

4. The multi-axis drive granulator printer lifting mechanism according to claim 1, characterized in that, The main drive mechanism (6) includes: The motor housing (601) is fixed to the top of the base frame (1); A servo motor (602) is installed inside the motor housing (601); The drive wheel (603) is fixedly connected to the motor shaft of the servo motor (602); The first bracket (604), two sets of second brackets (605) and the third bracket (606) are all fixedly connected to the top of the base (1); Two sets of first tensioning rollers (607) are rotatably mounted on the top of the first bracket (604) via bearings; Four sets of second tensioning rollers (608) are rotatably mounted on top of two sets of second brackets (605) via bearings; Two sets of anti-deviation wheels (609) are rotatably mounted on the top of the third bracket (606) via bearings.

5. The multi-axis drive granulator printer lifting mechanism according to claim 4, characterized in that, The transmission belt (7) is connected to four sets of passive pulleys (406), two sets of first tension pulleys (607), four sets of second tension pulleys (608), and two sets of anti-deviation pulleys (609).

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