Post-printing cigarette case label paper flatness adjusting device

Abstract

The invention provides a flatness adjusting device for printed cigarette case label paper, and belongs to a paper coating device. Comprising a side plate, an auxiliary device and an anti-curl shaping mechanism, a negative pressure adsorption mechanism is arranged on the inner side of the side plate, a humidifying mechanism, a drying mechanism and a reverse curling shaping mechanism are sequentially arranged on the top of the side plate, a servo electric cylinder of the reverse curling shaping mechanism is started to drive a threaded shaft to rotate in a threaded groove, an internal threaded block and a sliding block move front and back in the direction of a sliding groove, and when the internal threaded block moves forwards, the internal threaded block moves back and forth. When the internal thread block moves backwards, the anti-curling roller set is driven to move upwards, when the internal thread block moves backwards, the anti-curling roller set is driven to move downwards, paper is subjected to anti-curling, upward arch stress of the paper is counteracted, paper curl is automatically and rapidly eliminated through continuous circulation of the paper, and flatness is integrally improved.

Description

Technical Field

[0001] The invention relates to the technical field of paper coating devices, and in particular to a device for adjusting the flatness of printed cigarette box trademark paper. Background Art

[0002] There are two main reasons for paper curling. One is due to the difference in tension between the front and back sides of the paper, and the other is due to changes in humidity on the surface of the paper. Because the front of most printed products is covered with ink and varnish, it is difficult for water to enter the paper from the front, so in this environment, moisture will be absorbed from the back of the product, causing curling; especially single-sided coated paper, one side is coated and the other side is fiber, and the fiber and coating have different expansion coefficients for water, the fiber has a large expansion rate, while the coating has a small expansion rate; at the same time, there is a big difference in the water absorption of the two, the fiber absorbs water quickly and the coating absorbs water slowly; the water content of paper has a normal indicator range. Only by keeping the water content of each part of the whole paper balanced and consistent, can the paper maintain its normal physical properties: flat, no curling, no deformation.

[0003] However, in the actual paper storage and transportation process, poor packaging sealing or changes in humidity and temperature in storage conditions often lead to uneven absorption / loss of moisture, causing the paper to curl and deform, changing the smooth appearance of the paper.

[0004] As modern packaging machinery runs faster and faster, cigarette factories need very flat small box paper for cigarette packaging. Once the cigarette box label paper curls, it will cause great trouble to the packaging production line operation. Therefore, downstream companies have very strict requirements on the flatness of printed products.

[0005] The usual solution to the problem of paper curling is to print a back coating on the back of the paper. However, there are problems with its process control and final effect. In addition, back coating can basically maintain the flatness of the paper in a normal environment. Once the environmental humidity and temperature change greatly, the change of the back coating will exceed the preset range, and paper curling is still inevitable; if back coating is used to eliminate paper curling, the printing equipment needs to be modified, and the equipment cost and process cost will increase.

[0006] There are also methods of simply processing paper by humidification or drying. Although a certain flattening effect can be achieved, it is not subjected to shaping treatment. There is still a certain rebound during use, which affects subsequent processes. For example, application number 201420281908.X, invention name: Deformed paper wet and dry dual-purpose flattening device, including a paper input table, a paper conveying table, an automatic paper receiving table and a control console; the paper input table is connected to the input end of the paper conveying table, and the paper input table feeds the deformed paper into the paper conveying table through a feeder servo; a temperature and humidity detector is arranged above the paper input table; a protective cover is arranged outside the paper conveying table, and inside the protective cover, a plurality of dryers and humidifiers are arranged above the paper conveying table, and a temperature and humidity detector is arranged at the output end of the paper conveying table; the automatic paper receiving table is connected to the output end of the paper conveying table; the control console is connected to the dryer, the humidifier, the temperature and humidity detector and the drive motor, and the control console controls the operation of the dryer and the humidifier according to the data fed back by the temperature and humidity detector. Summary of the invention

[0007] The invention provides a device for adjusting the flatness of cigarette box trademark paper after printing, which is simple to adjust and can achieve the flatness standard after processing.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a device for adjusting the flatness of a printed cigarette box trademark paper, comprising a frame, a side panel 1, an auxiliary device 4 and an anti-curling shaping mechanism 5; a negative pressure adsorption mechanism is arranged on the inner side of the frame, a conveyor belt 2 of the negative pressure adsorption mechanism is arranged along the paper transmission direction, and a tension adjustment roller 201 is arranged on the transmission direction of the conveyor belt 2 located on the inner side of the frame, a humidity sensor 3 is arranged at the paper feeding end of the side panel 1, and an auxiliary device 4 and an anti-curling shaping mechanism 5 are arranged on the top in sequence.

[0009] The auxiliary device 4 includes a humidifying mechanism 41 and a drying mechanism 42; the humidifying mechanism 41 includes a servo motor 401, a half gear 402, a full gear 403, a rotating shaft 404, a baffle 405, a top plate 406, a water tank 407, a pressurizing chamber 408, an infrared receiver 409, an infrared transmitter 410 and a cross plate 411; the servo motor 401 is fixedly mounted on one side of the frame, and the output end of the servo motor 401 is fixedly mounted with a half gear 402, one side of the half gear 402 is meshed with a full gear 403, and one side of the full gear 403 is fixed A rotating shaft 404 is fixedly connected, a baffle 405 is fixedly connected to one side of the rotating shaft 404, a top plate 406 is arranged on the top of the half gear 402, a water tank 407 is fixedly installed on the top of the top plate 406, a boosting chamber 408 is connected to the bottom of the water tank 407, a plurality of atomizing nozzles 420 are arranged at the bottom of the boosting chamber 408, an electric-controlled opening and closing valve is arranged inside the boosting chamber 408, the electric-controlled opening and closing valve is electrically connected to the infrared receiver 409, an infrared transmitter 410 is arranged at the bottom of the infrared receiver 409, and the infrared transmitter 410 is fixedly installed on the top of the horizontal plate 411.

[0010] The drying mechanism 42 includes a drying chamber 412, an air inlet 413, a partition 414, a heating plate 415, a blower 416, and a guide plate 417; the drying chamber 412 is fixedly installed on the top of the side panel 1, an air inlet 413 is opened on one side of the drying chamber 412, a partition 414 is fixedly installed inside the drying chamber 412, and the inner cavity of the drying chamber 412 is divided into a first cavity 418 and a second cavity 419 by the partition 414, a heating plate 415 is arranged inside the first cavity 418, a guide plate 417 is connected to the bottom of the second cavity 419, and a blower 416 is arranged on one side of the second cavity 419.

[0011] Furthermore, the heating plate 415 is fixedly installed inside the air inlet 413 , and the heating plate 415 is tilted, and a hole penetrating the guide plate 417 is opened on the top of the guide plate 417 .

[0012] Furthermore, the anti-curling shaping mechanism 5 includes a paper feed roller group 501 and a paper discharge roller group 502 which are parallel to each other and form a channel for the paper and the conveyor belt 2 to pass through, and an anti-curling roller group 506 which is arranged between the paper feed roller group 501 and the paper discharge roller group 502 and can move up and down; the paper feed roller group 501 includes an upper paper feed roller and a lower paper feed roller, and the paper discharge roller group 502 includes an upper paper discharge roller and a lower paper discharge roller, the lower paper feed roller and the lower paper discharge roller are symmetrically fixedly connected to the frame and are located below the conveyor belt 2 and are in point contact with the conveyor belt 2, the upper paper feed roller and the upper paper discharge roller are located above the conveyor belt 2, and the upper paper feed roller and the upper paper discharge roller can be displaced up and down in the vertical groove 101 of the side plate to adjust the position distance from the lower paper feed roller and the lower paper discharge roller; The anti-curling roller group 506 includes an anti-curling upper roller and an anti-curling lower roller. The anti-curling lower roller is fixed on the movable plate 503. The movable plate 503 can move up and down in the movable groove 102 of the side plate 1. The two ends of the anti-curling upper roller are connected in the movable plate 503 with an adjustment mechanism for adjusting the distance between the anti-curling lower roller.

[0013] The mechanism for moving the anti-curling roller group 506 up and down includes a main connecting rod 507, a third connecting rod 508, an internal thread block 509, a thread groove 510, a threaded shaft 511, a servo electric cylinder 512 and a slider 513; one side of the anti-curling roller group 506 is movably connected with the main connecting rod 507, the main connecting rod 507 is movably installed on one side of the side plate 1, one side of the main connecting rod 507 is hinged with the third connecting rod 508, one side of the third connecting rod 508 is hinged with the internal thread block 509, one side of the internal thread block 509 is provided with a thread groove 510, the internal thread of the thread groove 510 is threadedly sleeved with a threaded shaft 511, the threaded shaft 511 is fixedly installed on one side of the output shaft of the servo electric cylinder 512, and one side of the internal thread block 509 is fixedly connected with a slider 513.

[0014] Furthermore, the slider 513 is movably connected to the inside of a groove opened on one side of the side panel 1, the servo electric cylinder 512 is fixedly installed on one side of the side panel 1, and the anti-curling roller group 506, the main connecting rod 507 and the third connecting rod 508 are symmetrically arranged with the threaded groove 510 as the center point.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention sets a baffle to determine whether the batch of cigarette box papers needs humidification or dehumidification treatment according to the detection situation. The baffle is used to block the cigarette box papers on the conveyor belt, and the thrust of the conveyor belt to move the cigarette box papers is used to align the cigarette box papers with the baffle, so that the cigarette box papers are confined below the booster bin for uniform humidification or drying.

[0016] 2. The present invention sets an anti-curling roller group. After the curled paper is humidified or dehumidified, it continues to move forward and passes through the anti-curling roller group. The anti-curling roller group is adjusted to move upward or downward. The higher the curling degree, the more the anti-curling movement is to both sides, so that the anti-curling roller group forms a reverse pressure on the curling direction of the paper, and the paper roll is anti-curled to offset the upward arch stress of the paper. Through the continuous circulation of the paper, the curl of the paper is automatically and quickly eliminated, and the overall flatness is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the main structure of the present invention.

[0018] Figure 2 It is a schematic diagram of the structure of the present invention in the anti-curling state.

[0019] Figure 3 It is a schematic diagram of the main structure of the humidifying mechanism of the present invention.

[0020] Figure 4 It is a schematic diagram of the partial structure of the utility model humidifying mechanism.

[0021] Figure 5 This is a schematic diagram of the main structure of the drying mechanism of the utility model.

[0022] Figure 6 This is a cross-sectional view of the drying mechanism of the utility model.

[0023] Figure 7 It is a schematic diagram of the structure of the anti-curling shaping mechanism of the utility model.

[0024] Figure 8 The utility model is a schematic diagram of the transmission principle of the anti-curling shaping mechanism.

[0025] In the figure: 1, side plate; 101, vertical slot; 102, moving slot; 2, conveyor belt; 201, tension adjustment roller; 3, humidity sensor; 4, auxiliary device; 41, humidification mechanism; 42, drying mechanism; 401, servo motor; 402, half gear; 403, full gear; 404, rotating shaft; 405, baffle; 406, top plate; 407, water tank; 408, booster chamber; 409, infrared receiver; 410, infrared transmitter; 411, horizontal plate; 412, Drying chamber; 413, air inlet; 414, partition; 415, heating plate; 416, blower; 417, guide plate; 418, first cavity; 419, second cavity; 420, atomizing nozzle; 5, anti-curling shaping mechanism; 501, paper feed pressure roller group; 502, paper discharge pressure roller group; 506, anti-curling roller group; 507, main connecting rod; 508, third connecting rod; 509, internal thread block; 510, thread groove; 511, threaded shaft; 512, handle; 513, slider. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Example 1

[0027] like Figure 1 As shown in FIG. 8 , the present invention provides a device for adjusting the flatness of printed cigarette box trademark paper, comprising a frame, a side panel 1, an auxiliary device 4 and an anti-curling shaping mechanism 5; a negative pressure adsorption mechanism is arranged on the inner side of the frame, a conveyor belt 2 of the negative pressure adsorption mechanism is arranged along the paper transmission direction, and a tension adjustment roller 201 is arranged on the transmission direction of the conveyor belt 2 located on the inner side of the frame, a humidity sensor 3 is arranged at the paper feeding end of the side panel 1, and an auxiliary device 4 and an anti-curling shaping mechanism 5 are arranged on the top in sequence.

[0028] The auxiliary device 4 includes a humidifying mechanism 41 and a drying mechanism 42. Figure 3 , Figure 4As shown, the humidification mechanism 41 includes a servo motor 401, a half gear 402, a full gear 403, a rotating shaft 404, a baffle 405, a top plate 406, a water tank 407, a pressurization chamber 408, an infrared receiver 409, an infrared transmitter 410 and a cross plate 411. The servo motor 401 is fixedly mounted on one side of the side plate 1, and the output end of the servo motor 401 is fixedly mounted with a half gear 402, one side of the half gear 402 is meshed with a full gear 403, and one side of the full gear 403 is fixedly connected There is a rotating shaft 404, a baffle 405 is fixedly connected to one side of the rotating shaft 404, a top plate 406 is arranged on the top of the half gear 402, a water tank 407 is fixedly installed on the top of the top plate 406, the bottom of the water tank 407 is connected to a boosting chamber 408, an electric control opening and closing valve is arranged inside the boosting chamber 408, and the electric control opening and closing valve is electrically connected to an infrared receiver 409, an infrared transmitter 410 is arranged at the bottom of the infrared receiver 409, and the infrared transmitter 410 is fixedly installed on the top of the horizontal plate 411.

[0029] like Figure 5 , Figure 6 As shown, the drying mechanism 42 includes a drying chamber 412, an air inlet 413, a partition 414, a heating plate 415, a blower 416 and a guide plate 417. The drying chamber 412 is fixedly installed on the top of the side panel 1, and an air inlet 413 is opened on one side of the drying chamber 412. A partition 414 is fixedly installed inside the drying chamber 412. The inner cavity of the drying chamber 412 is divided into a first cavity 418 and a second cavity 419 by the partition 414. A heating plate 415 is arranged inside the first cavity 418. The heating plate 415 is fixedly installed inside the air inlet 413, and the heating plate 415 is inclined. The bottom of the second cavity 419 is connected to the guide plate 417, and a hole penetrating the guide plate 417 is opened on the top of the guide plate 417. A blower 416 is arranged on one side of the second cavity 419.

[0030] According to the detection result of the humidity sensor 3, it is determined whether to use humidification or drying treatment for the cigarette box paper. The cigarette box paper moves through the conveyor belt 2. When the cigarette box paper moves to one side of the baffle 405, it is blocked by the baffle 405 and stops for a while. The servo motor 401 drives the half gear 402 to rotate. When the half gear 402 rotates one circle, it has only half the effective meshing time with the full gear 403. When the half gear 402 and the full gear 403 are meshed for transmission, the full gear 403 drives the rotating shaft 404 to rotate. At this time, the baffle 405 is lifted upward driven by the rotating shaft 404, and the cigarette box paper can continue to move forward driven by the conveyor belt 2. When the half gear 402 is idling and not meshing with the full gear 403, the cigarette box paper baffle 405 blocks it, and the infrared ray emitted by the infrared transmitter 410 to the infrared receiver 409 is blocked by the cigarette box paper. When the infrared receiver 409 cannot receive the infrared ray emitted by the infrared transmitter 410, a signal is sent to the electrically controlled opening and closing valve inside the boosting chamber 408 to control the opening and closing valve to open. At this time, the atomizing nozzle at the bottom of the boosting chamber 408 humidifies the cigarette box paper at the bottom.

[0031] If the batch of cigarette paper needs to be dried, the hot air heated by the heating plate 415 is blown toward the cigarette paper on the conveyor belt 2 under the action of the blower 416 and the guide plate 417.

[0032] like Figure 7 and Figure 8 As shown, the anti-curling shaping mechanism 5 includes a paper feed roller group 501 and a paper discharge roller group 502 which are parallel to each other and form a channel for the cigarette box paper and the conveyor belt 2 to pass through, and an anti-curling roller group 506 which is arranged between the paper feed roller group 501 and the paper discharge roller group 502 and can move up and down; the paper feed roller group 501 includes an upper paper feed roller and a lower paper feed roller, and the paper discharge roller group 502 includes an upper paper discharge roller and a lower paper discharge roller, the lower paper feed roller and the lower paper discharge roller are symmetrically fixedly connected to the frame and are located below the conveyor belt 2 and are in point contact with the conveyor belt 2, the upper paper feed roller and the upper paper discharge roller are located above the conveyor belt 2, the upper paper feed roller and the upper paper discharge roller can be displaced up and down in the vertical groove 101 of the side plate, and are used to adjust the position distance from the lower paper feed roller and the lower paper discharge roller.

[0033] The anti-curling roller group 506 includes an anti-curling upper roller and an anti-curling lower roller. The anti-curling lower roller is fixed on the movable plate 503. The movable plate 503 can move up and down in the movable groove 102 of the side plate 1. The two ends of the anti-curling upper roller are connected in the movable plate 503 with an adjustment mechanism for adjusting the distance between the anti-curling lower roller.

[0034] The mechanism for moving the anti-curling roller group 506 up and down includes a main connecting rod 507, a third connecting rod 508, an internal thread block 509, a thread groove 510, a threaded shaft 511, a servo electric cylinder 512 and a slider 513; one side of the anti-curling roller group 506 is movably connected with the main connecting rod 507, the main connecting rod 507 is movably installed on one side of the side plate 1, one side of the main connecting rod 507 is hinged with the third connecting rod 508, one side of the third connecting rod 508 is hinged with the internal thread block 509, one side of the internal thread block 509 is provided with a thread groove 510, the internal thread of the thread groove 510 is threadedly sleeved with a threaded shaft 511, the threaded shaft 511 is fixedly installed on one side of the output shaft of the servo electric cylinder 512, and one side of the internal thread block 509 is fixedly connected with a slider 513. The slider 513 is movably connected to the inside of a groove opened on one side of the side plate 2, the servo electric cylinder 512 is fixedly installed on one side of the side plate 1, and the anti-curling roller group 506, the main connecting rod 507 and the third connecting rod 508 are symmetrically arranged with the thread groove 510 as the center point.

[0035] By starting the servo electric cylinder 512 to drive the threaded shaft 511 to rotate, under the restriction of the slider 513 inside the slide groove on one side of the side plate 1, the internal thread block 509 can only move forward or backward along the direction of the slide groove on one side of the side plate 1 under the drive of the threaded shaft 511. When the internal thread block 509 moves forward, the internal thread block 509 drives the third connecting rod 508 to prop up the main connecting rod 507, thereby driving the anti-curling roller group 506 to move upward; or the servo electric cylinder 512 is controlled to rotate in the opposite direction, thereby driving the internal thread block 509 to move backward, at which time the third connecting rod 508 drives the main connecting rod 507 to move downward, thereby driving the anti-curling roller group 506 to move downward. The anti-curling roller group forms a reverse pressure on the curling direction of the paper. When it is necessary to adjust the anti-curling roller group 506, the tension of the tension adjustment roller 201 is adjusted accordingly to keep the tension of the entire conveyor belt 2 balanced.

Claims

1. A device for adjusting the flatness of printed cigarette box label paper, characterized in that: The invention comprises a frame, a side plate (1), an auxiliary device (4) and an anti-curling shaping mechanism (5); a negative pressure adsorption mechanism is arranged on the inner side of the frame, a conveyor belt (2) of the negative pressure adsorption mechanism is arranged along the paper conveying direction, and a tension adjustment roller (201) is arranged on the conveying direction of the conveyor belt (2) located on the inner side of the frame, a humidity sensor (3) is arranged on the paper feeding end of the side plate (1), and an auxiliary device (4) and an anti-curling shaping mechanism (5) are arranged on the top in sequence; The auxiliary device (4) comprises a humidifying mechanism (41) and a drying mechanism (42); the humidifying mechanism (41) comprises a servo motor (401), a half gear (402), a full gear (403), a rotating shaft (404), a baffle (405), a top plate (406), a water tank (407), a pressurizing chamber (408), an infrared receiver (409), an infrared transmitter (410) and a transverse plate (411); the servo motor (401) is fixedly mounted on one side of the frame, a half gear (402) is fixedly mounted on the output end of the servo motor (401), a full gear (403) is meshed and driven on one side of the half gear (402), and the full gear (403) is meshed and driven on one side of the half gear (402), and the full gear (403) is meshed and driven on the other side of the half gear (402). ) is fixedly connected to one side of the half gear (402), a baffle (405) is fixedly connected to one side of the rotating shaft (404), a top plate (406) is arranged on the top of the half gear (402), a water tank (407) is fixedly installed on the top of the top plate (406), a pressurizing chamber (408) is connected to the bottom of the water tank (407), a plurality of atomizing nozzles (420) are arranged at the bottom of the pressurizing chamber (408), an electric-controlled opening and closing valve is arranged inside the pressurizing chamber (408), the electric-controlled opening and closing valve is electrically connected to the infrared receiver (409), an infrared transmitter (410) is arranged at the bottom of the infrared receiver (409), and the infrared transmitter (410) is fixedly installed on the top of the horizontal plate (411).

2. The device for adjusting the flatness of printed cigarette box label paper according to claim 1, characterized in that: The drying mechanism (42) comprises a drying chamber (412), an air inlet (413), a partition (414), a heating plate (415), a blower (416), and a guide plate (417); the drying chamber (412) is fixedly mounted on the top of the side plate (1); an air inlet (413) is provided on one side of the drying chamber (412); a partition (414) is fixedly mounted inside the drying chamber (412); the inner cavity of the drying chamber (412) is divided into a first cavity (418) and a second cavity (419) by the partition (414); a heating plate (415) is provided inside the first cavity (418); the bottom of the second cavity (419) is connected to the guide plate (417); and a blower (416) is provided on one side of the second cavity (419).

3. The device for adjusting the flatness of printed cigarette box label paper according to claim 2, characterized in that: The heating plate (415) is fixedly mounted inside the air inlet (413), and the heating plate (415) is arranged at an angle, and a hole penetrating the guide plate (417) is provided at the top of the guide plate (417).

4. A device for adjusting the flatness of printed cigarette box label paper according to any one of claims 1 to 3, characterized in that: The anti-curling shaping mechanism (5) comprises a paper feed roller group (501) and a paper discharge roller group (502) which are parallel to each other and form a passage for the paper and the conveyor belt 2 to pass through, and an anti-curling roller group (506) which is arranged between the paper feed roller group (501) and the paper discharge roller group (502) and can move up and down; the paper feed roller group (501) comprises an upper paper feed roller and a lower paper feed roller, and the paper discharge roller group (502) comprises an upper paper discharge roller and a lower paper discharge roller, the paper feed roller and the lower paper discharge roller are symmetrically fixedly connected to the frame and are located below the conveyor belt (2) and are in point contact with the conveyor belt (2), the paper feed roller and the upper paper discharge roller are located above the conveyor belt (2), and the paper feed roller and the upper paper discharge roller can move up and down in the vertical groove (101) of the side plate to adjust the position distance with the paper feed roller and the lower paper discharge roller; The anti-curling roller group (506) comprises an anti-curling upper roller and an anti-curling lower roller, the anti-curling lower roller being fixed on a movable plate (503), the movable plate (503) being movable up and down in a movable groove (102) of the side plate (1), and both ends of the anti-curling upper roller being connected in the movable plate 503 with an adjustment mechanism for adjusting the distance between the anti-curling upper roller and the anti-curling lower roller.

5. The device for adjusting the flatness of printed cigarette box label paper according to claim 4, characterized in that: The mechanism for moving the anti-curling roller group (506) up and down comprises a main connecting rod (507), a third connecting rod (508), an internal thread block (509), a thread groove (510), a threaded shaft (511), a servo electric cylinder (512) and a slider (513); one side of the anti-curling roller group (506) is movably connected to the main connecting rod (507), the main connecting rod (507) is movably mounted on one side of the side plate (1), one side of the main connecting rod (507) is hinged to the third connecting rod (508), one side of the third connecting rod (508) is hinged to the internal thread block (509), one side of the internal thread block (509) is provided with a thread groove (510), the internal thread of the thread groove (510) is threadedly sleeved with a threaded shaft (511), the threaded shaft (511) is fixedly mounted on one side of the output shaft of the servo electric cylinder (512), and one side of the internal thread block (509) is fixedly connected to the slider (513).

6. The device for adjusting the flatness of printed cigarette box label paper according to claim 5, characterized in that: The slider (513) is movably connected to the inside of a groove opened on one side of the side plate (1), the servo electric cylinder (512) is fixedly installed on one side of the side plate (1), and the anti-curling roller group (506), the main connecting rod (507) and the third connecting rod (508) are symmetrically arranged with the thread groove (510) as the center point.

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