A corrugated cardboard single-face machine

Abstract

The present invention provides a corrugated cardboard single-facer, relating to the field of corrugated cardboard production equipment. The single-facer includes a frame, an upper preheating roller, an upper corrugating roller, a lower corrugating roller, a lower preheating roller, a pressure roller, a gluing roller, a glue cutting roller, a glue trough, a corrugated cardboard guide wheel, an upper guide adjustment wheel, a lower guide adjustment wheel, a face paper guide wheel, and an air blowing and suction mechanism. The rubber cutting roller is circumferentially provided with multiple glue cutting knives of different lengths. The rubber cutting roller is rotatably mounted on a pair of symmetrical glue amount fine-tuning mechanisms. The upper guide adjustment wheel and the lower guide adjustment wheel are both movably connected to a tension adjustment mechanism provided in the frame. The corrugated cardboard single-facer of the present invention does not have the problem of heating medium leakage, and the heating is uniform, and the equipment energy consumption is reduced. The tension adjustment mechanism can fine-tune the positions of the upper guide adjustment wheel and the lower guide adjustment wheel to simultaneously change the tension of the core paper and the face paper.

Description

Technical Field

[0001] The invention relates to the field of corrugated paper production equipment, in particular to a corrugated paperboard single-facer. Background Art

[0002] A single-facer is a machine used to produce corrugated cardboard. Its main components include a base paper support, corrugating rollers, pressure rollers, preheating rollers, and a gluing device. When using a single-facer to continuously produce single-faced corrugated cardboard, the core paper is first heated and then passed through pairs of corrugating rollers to form the desired flute shape. Glue (starch adhesive) is then applied to the flutes of the core paper and bonded to the face paper to form the single-faced corrugated cardboard.

[0003] At present, the heating methods for core paper include steam heating, electric heating and oil heating. Steam heating and oil heating have the problems of low efficiency and high energy consumption, and are prone to leakage, which will contaminate the paper. The existing electric heating method has the problem of uneven heat transfer.

[0004] CN 203919857 U discloses a single-facer for producing corrugated cardboard, comprising a frame, an upper preheating roller, an upper corrugating roller, a lower corrugating roller, a pressure roller and a lower preheating roller sequentially distributed on the frame, the lower corrugating roller comprising a roller body, a hollow negative pressure chamber being provided in the roller body, semicircular arc-shaped or annular suction grooves being evenly distributed on the roller body in proportion, and suction holes connecting the suction grooves and the negative pressure chamber being opened on the roller body, an air pump being externally connected to the negative pressure chamber, a paper guide roller being further provided at a position corresponding to the pressure roller on the frame, an air jet being provided between the pressure roller and the paper guide roller, and the air jet being connected to the air pump. The single-facer controls the amount of glue by the gap between the glue coating roller and the glue leveling roller. However, during the production of corrugated cardboard by the corrugated cardboard single-facer, a large amount of fine paper scraps will be generated when the corrugating roller rolls the cardboard. The paper scraps that have not fallen off are very likely to adhere to the glue coating roller during glue coating, interfering with the glue coating ability of the glue coating device and causing uneven glue coating thickness. When the adhered paper scraps are too thick, it is very likely to cause shutdown for maintenance, thereby reducing the production efficiency of the corrugated cardboard single-facer. In addition, the air pump sucks a large amount of air from the negative pressure cavity in the roller body of the lower corrugating roller, which will cause a high heat energy loss in the lower corrugating roller. The lower corrugating roller requires heat energy to promote corrugation forming and gluing. The loss of heat energy inside the lower corrugating roller has a negative impact on the energy consumption of the single-facer. Summary of the Invention

[0005] The purpose of the present invention is to provide a corrugated cardboard single-facer to address the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A single-facer for corrugated cardboard comprises a frame, wherein an upper preheating roller, an upper corrugating roller, a lower corrugating roller, a lower preheating roller, a pressure roller, a glue coating roller, a glue cutting roller, a glue groove and a corrugated cardboard guide wheel are arranged in the frame;

[0008] The upper corrugated roller is located directly above the lower corrugated roller, and the upper corrugated roller and the lower corrugated roller are in conflict with each other and form a gap for the core paper to pass through. The pressure roller is located on the lower right side of the lower corrugated roller, and the pressure roller and the lower corrugated roller are in conflict with each other and form a gap for the corrugated core paper and the face paper to pass through for gluing.

[0009] The glue coating roller is located at the lower left of the lower corrugated roller, and the glue coating roller contacts the lower corrugated roller. The glue cutting roller is located on the left side of the glue coating roller. A plurality of glue cutting knives of different lengths are arranged circumferentially on the roller body of the glue cutting roller. A gap is left between the glue cutting knives and the glue coating roller. The rotating shafts at both ends of the roller body of the glue cutting roller are respectively rotatably mounted on a pair of symmetrical glue amount fine-adjusting mechanisms. The lower part of the glue coating roller is immersed in the glue liquid in the glue tank.

[0010] The upper preheating roller and the lower preheating roller are both electromagnetic induction heating round rollers;

[0011] An upper guide adjustment wheel is provided at the lower left of the upper preheating roller, and a lower guide adjustment wheel is provided at the upper left of the lower preheating roller. The upper guide adjustment wheel is located directly above the lower guide adjustment wheel. Both the upper guide adjustment wheel and the lower guide adjustment wheel are movably connected to a tension adjustment mechanism provided in the frame. The tension adjustment mechanism is used to simultaneously adjust the positions of the upper guide adjustment wheel and the lower guide adjustment wheel.

[0012] A facial paper guide wheel is provided between the lower preheating roller and the pressure roller in the facial paper conveying direction.

[0013] Furthermore, the lower corrugating roller adopts electromagnetic induction heating.

[0014] Furthermore, the rubber cutting knife includes a knife head and a blade body. There is an angle β between the central axis of the blade body and the radial direction of the rubber cutting roller, and β is between 0° and 30°. The knife head is an outward convex arc.

[0015] Preferably, the width of the blade head portion is greater than the width of the blade body portion.

[0016] The axle up and down groove at two ends embeds respectively in two guide rails up and down of being made up of the groove on the attachment piece, and the tooth on the attachment piece is meshed with tooth on upper sprocket wheel, the lower sprocket.

[0017] Furthermore, the glue amount fine-tuning mechanism includes a second electric push rod, a bearing seat, a support, and a guide rail. The support is installed in the frame, the dovetail-shaped guide rail is fixed to the top of the support, and a slide groove matching the guide rail is provided at the bottom of the bearing seat. The rotating shafts at both ends of the roller body of the rubber cutting roller are rotatably installed in the bearing seat. The second electric push rod is fixed on the support, and its movable end is connected to the left side of the bearing seat.

[0018] Furthermore, the corrugated cardboard single-facer also includes an air blowing and suction mechanism, which includes a shell, and the shell includes a guide curved surface in sliding contact with the right lower side of the upper corrugated roller, a sealing curved surface in sliding contact with the right upper side of the lower corrugated roller, and a separation curved surface in sliding contact with the right lower side of the lower corrugated roller. An air pump is arranged in the shell, and the air inlet end of the air inlet pipe of the air pump is located at the connection between the guide curved surface and the sealing curved surface, and the air outlet end of the air outlet pipe of the air pump is located at the connection between the sealing curved surface and the separation curved surface.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] 1. The upper preheating roller, lower preheating roller and lower corrugating roller provided in the corrugated cardboard single-facer of the present invention are all heated by electromagnetic means, and do not require heating media such as steam and thermal oil. There is no leakage problem, and the heating is uniform, which reduces the energy consumption of the equipment.

[0021] 2. The rubber cutting roller provided in the corrugated cardboard single-facer of the present invention is provided with rubber cutting knives of different installation lengths. By rotating the rubber cutting roller body and replacing the rubber cutting knives, the amount of glue applied to the rubber coating roller can be quickly adjusted. With the assistance of the rubber amount fine-tuning mechanism, the accuracy of the adjustment of the amount of glue applied to the rubber coating roller can be improved.

[0022] 3. The first electric push rod provided in the corrugated cardboard single-facer of the present invention pushes and pulls the double-sided rack to move left and right to change the rotation angle of the upper adjustment arm and the lower adjustment arm, and then simultaneously changes the position of the upper guide adjustment wheel and the lower guide adjustment wheel; moreover, the collar, the first connecting rod, the cylinder, the slider, and the spring form an automatic buffer adjustment structure, which can fine-tune the position of the upper guide adjustment wheel and the lower guide adjustment wheel. The change in the position of the upper guide adjustment wheel and the lower guide adjustment wheel can adjust the tension of the core paper and the face paper.

[0023] 4. The guide curved surface of the shell of the air blowing and suction mechanism provided in the corrugated cardboard single-facer of the present invention guides the core paper into between the upper corrugated roller and the lower corrugated roller. The smooth separation curved surface is conducive to the separation of the single-faced corrugated cardboard from the lower corrugated roller. The air pump sucks the air in the gap between the lower corrugated roller and the core paper, which is conducive to the close fit of the core paper to the lower corrugated roller. The hot air sucked by the air pump is blown into the gap between the lower corrugated roller and the single-faced corrugated cardboard, which is conducive to the smooth separation of the single-faced corrugated cardboard from the lower corrugated roller. The sealing curved surface limits the suction and blowing areas of the air pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a structural diagram of a corrugated cardboard single-facer machine according to an embodiment of the present invention;

[0025] Figure 2 for Figure 1 A three-dimensional view of the center-cut rubber roller;

[0026] Figure 3 for Figure 2 Right side view of the center-cut rubber roller;

[0027] Figure 4 for Figure 1 Schematic diagram of the structure of the middle and upper adjustment arm;

[0028] Figure 5 for Figure 4 Front view of the middle and upper adjustment arm;

[0029] Figure 6 for Figure 5 Cross-sectional view along the AA axis;

[0030] Figure 7 for Figure 1 A partial enlarged view of point B in the middle;

[0031] Figure 8 for Figure 1 A partial enlarged view of point C in the middle;

[0032] Figure numerals: 1-frame, 2-upper guide adjustment wheel, 3-upper preheating roller, 4-upper corrugating roller, 5-lower corrugating roller, 6-lower guide adjustment wheel, 7-lower preheating roller, 8-face paper guide wheel, 9-pressure roller, 10-glue coating roller, 11-glue cutting roller, 1101-roller body, 1102-glue cutting knife, 1102a-knife head, 1102b-knife body, 12-glue groove, 13-corrugated board guide wheel, 14-upper adjustment arm, 1401-ring, 1402-first connecting rod , 1403-cylinder, 1404-second connecting rod, 1405-gear, 1406-slider, 1407-slide groove, 1408-spring, 1409-through hole, 15-lower adjusting arm, 16-double-sided rack, 17-first electric push rod, 18-bearing seat, 19-support, 20-guide rail, 21-second electric push rod, 22-housing, 22a-guide surface, 22b-sealing surface, 22c-separation surface, 23-air pump, 24-exhaust pipe, 25-injection pipe. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0034] like Figure 1-8 As shown, a corrugated cardboard single-facer of this embodiment includes a frame 1, in which an upper preheating roller, an upper corrugating roller 4, a lower corrugating roller 5, a lower preheating roller, a pressure roller 9, a glue coating roller 10, a glue cutting roller 11, a glue groove 12, and a corrugated cardboard guide wheel 13 are arranged;

[0035] The upper corrugated roller 4 is located directly above the lower corrugated roller 5, and the upper corrugated roller 4 and the lower corrugated roller 5 are in conflict with each other and form a gap for the core paper to pass through. The pressure roller 9 is located on the lower right side of the lower corrugated roller 5, and the pressure roller 9 and the lower corrugated roller 5 are in conflict with each other and form a gap for the corrugated core paper and the face paper to pass through for gluing;

[0036] The glue coating roller 10 is located at the lower left of the lower corrugating roller 5, and the glue coating roller 10 is in conflict with the lower corrugating roller 5. The glue cutting roller 11 is located on the left side of the glue coating roller 10. A plurality of glue cutting knives 1102 of different lengths are circumferentially arranged on the roller body 1101 of the glue cutting roller 11. A gap is left between the glue cutting knives 1102 and the glue coating roller 10. The rotating shafts at both ends of the roller body 1101 of the glue cutting roller 11 are respectively rotatably mounted on a pair of symmetrical glue amount fine-adjustment mechanisms. The lower part of the glue coating roller 10 is immersed in the glue liquid in the glue tank 12.

[0037] The upper preheating roller and the lower preheating roller are both electromagnetic induction heating round rollers;

[0038] An upper guide adjustment wheel 2 is provided at the lower left of the upper preheating roller, and a lower guide adjustment wheel 6 is provided at the upper left of the lower preheating roller. The upper guide adjustment wheel 2 is located directly above the lower guide adjustment wheel 6. The upper guide adjustment wheel 2 and the lower guide adjustment wheel 6 are both movably connected to a tension adjustment mechanism provided in the frame 1. The tension adjustment mechanism is used to simultaneously adjust the positions of the upper guide adjustment wheel 2 and the lower guide adjustment wheel 6.

[0039] A facial paper guide wheel 8 is provided between the lower preheating roller and the pressure roller 9 in the facial paper conveying direction.

[0040] In this embodiment, the core paper and the face paper enter the frame 1 from the left side one above and one below. The core paper passes around the upper guide adjustment wheel 2, is preheated by the upper preheating roller 3, and then passes around the upper corrugating roller 4. The upper corrugating roller 4 and the lower corrugating roller 5 pressurize and wrinkle the heated core paper to form corrugations; at the same time, the face paper passes around the lower guide adjustment wheel 6, is preheated by the lower preheating roller 7, and then passes around the face paper guide wheel 8 and the pressure roller 9. The corrugated core paper peaks are coated with glue by the glue roller 10 and then glued with the face paper between the lower corrugating roller 5 and the pressure roller 9 to form a single-sided corrugated board, which is then led out from the right side of the frame 1 through the corrugated board guide wheel 13.

[0041] Specifically, the lower corrugating roller 5 adopts electromagnetic induction heating, and the upper preheating roller, the lower preheating roller and the lower corrugating roller 5 are all heated by electromagnetic means, which does not require heating media such as steam and thermal oil, does not have leakage problems, and heats evenly.

[0042] Specifically, the rubber cutting knife 1102 includes a blade head 1102a and a blade body 1102b. There is an angle β between the central axis of the blade body 1102b and the radial direction of the rubber cutting roller 11. The angle β is between 0° and 30°. The blade head 1102a is an outward convex arc shape; the width of the blade head 1102a is greater than the width of the blade body 1102b. Preferably, the angle β is 15°.

[0043] In this embodiment, the rubber cutting roller 11 is driven to rotate by a rubber cutting motor connected to a rotating shaft on one side of the roller body 1101 of the rubber cutting roller 11, and the rubber cutting knife 1102 is replaced to adjust the amount of glue applied by the rubber coating roller 10.

[0044] Specifically, the tension adjustment mechanism includes a symmetrically arranged upper adjustment arm 14, a lower adjustment arm 15, a double-sided rack 16, and a first electric push rod 17. The first electric push rod 17 and the double-sided rack 16 are all horizontally arranged. The bottom of the first electric push rod 17 is fixed to the frame 1, and its movable end is fixedly connected to one end of the double-sided rack 16. The upper adjustment arm 14 includes a collar 1401, a first connecting rod 1402, a cylinder 1403, a second connecting rod 1404, and a gear 1405. The collar 1401 is rotatably sleeved on the rotating shaft of the upper guide adjustment wheel 2. One end of the first connecting rod 1402 is connected to the collar 1401, and the other end extends into the cylinder 1403 and is connected to the slider 1406. A plurality of dovetail groove-shaped slide grooves 1407 are circumferentially provided on the inner wall of the body 1403, a plurality of guide bars matching the slide grooves 1407 are provided on the outer periphery of the slider 1406, a spring 1408 is provided between the slider 1406 and the bottom surface of the cylinder 1403, a second connecting rod 1404 is provided on the outer side of the bottom surface of the cylinder 1403, a gear 1405 is provided on the second connecting rod 1404, the gear 1405 is engaged with the teeth on the double-sided rack 16, a through hole 1409 is provided on the end of the second connecting rod 1404 close to the gear 1405, the second connecting rod 1404 is rotatably connected to the corresponding mounting shaft provided on the frame 1 through the through hole 1409, and the structure of the lower adjusting arm 15 is the same as that of the upper adjusting arm 14.

[0045] In some preferred embodiments, the double-sided rack 16 is guided by a guide rail 20 to ensure the translation stability of the double-sided rack 16 .

[0046] In this embodiment, the double-sided rack 16 is pushed and pulled left and right by the first electric push rod 17 to change the rotation angle of the upper adjustment arm 14 and the lower adjustment arm 15, and then the position of the upper guide adjustment wheel 2 and the lower guide adjustment wheel 6 are changed at the same time; moreover, the ring 1401, the first connecting rod 1402, the cylinder 1403, the slider 1406, and the spring 1408 form an automatic buffer adjustment structure, which can fine-tune the position of the upper guide adjustment wheel 2 and the lower guide adjustment wheel 6. The change in the position of the upper guide adjustment wheel 2 and the lower guide adjustment wheel 6 can adjust the tension of the core paper and the surface paper.

[0047] Specifically, the glue amount fine-tuning mechanism includes a second electric push rod 21, a bearing seat 18, a support 19, and a guide rail 20. The support 19 is installed in the frame 1, and the dovetail-shaped guide rail 20 is fixed to the top of the support 19. A slide groove 1407 matching the guide rail 20 is provided at the bottom of the bearing seat 18. The rotating shafts at both ends of the roller body 1101 of the rubber cutting roller 11 are rotatably installed in the bearing seat 18. The second electric push rod 21 is fixed on the support 19, and its movable end is connected to the left side of the bearing seat 18.

[0048] In this embodiment, the second electric push rod 21 pushes and pulls the bearing seat 18 to change the distance between the rubber cutting roller 11 and the rubber coating roller 10, and can adjust the distance between the rubber cutting knife 1102 and the rubber coating roller 10. The second electric push rod 21 cooperates with the rubber cutting motor to more accurately adjust the amount of glue applied to the rubber coating roller 10.

[0049] Specifically, the corrugated cardboard single-facer also includes an air blowing and suction mechanism, which includes a shell 22. The shell 22 includes a guide curved surface 22a that is in sliding contact with the lower right side of the upper corrugating roller 4, a sealing curved surface 22b that is in sliding contact with the upper right side of the lower corrugating roller 5, and a separation curved surface 22c that is in sliding contact with the lower right side of the lower corrugating roller 5. An air pump 23 is provided in the shell 22. The air inlet end of the air inlet pipe of the air pump 23 is located at the connection between the guide curved surface 22a and the sealing curved surface 22b, and the air outlet end of the air outlet pipe of the air pump 23 is located at the connection between the sealing curved surface 22b and the separation curved surface 22c.

[0050] In this embodiment, the guide curved surface 22a guides the core paper to enter between the upper corrugated roller 4 and the lower corrugated roller 5, the smooth separation curved surface 22c is conducive to the single-faced corrugated board separating from the lower corrugated roller 5, the air pump 23 sucks the air in the gap between the lower corrugated roller 5 and the core paper, which is conducive to the core paper closely fitting the lower corrugated roller 5, and the hot air sucked by the air pump 23 is blown into the gap between the lower corrugated roller 5 and the single-faced corrugated board, which is conducive to the single-faced corrugated board smoothly separating from the lower corrugated roller 5, and the sealing curved surface 22b limits the suction and blowing area of ​​the air pump 23.

[0051] Although some specific technical solutions of the present invention have been described in detail through embodiments, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art of the present invention may make various modifications or additions to the described specific embodiments or replace them in similar ways, but they will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the scope of protection of the present invention.

Claims

1. A corrugated cardboard single-facer, comprising a frame (1), wherein the frame (1) is provided with an upper preheating roller, an upper corrugating roller (4), a lower corrugating roller (5), a lower preheating roller, a pressure roller (9), a glue coating roller (10), a glue cutting roller (11), a glue groove (12), and a corrugated cardboard guide wheel (13); characterized in that: The upper corrugated roller (4) is located directly above the lower corrugated roller (5), and the upper corrugated roller (4) and the lower corrugated roller (5) are in contact with each other and form a gap for the core paper to pass through; the pressure roller (9) is located on the lower right side of the lower corrugated roller (5), and the pressure roller (9) and the lower corrugated roller (5) are in contact with each other and form a gap for the corrugated core paper and the face paper to pass through by gluing; The glue coating roller (10) is located at the lower left of the lower corrugated roller (5), and the glue coating roller (10) contacts the lower corrugated roller (5). The glue cutting roller (11) is located at the left side of the glue coating roller (10). A plurality of glue cutting knives (1102) of different lengths are arranged circumferentially on the roller body (1101) of the glue cutting roller (11). A gap is left between the glue cutting knives (1102) and the glue coating roller (10). The rotating shafts at both ends of the roller body (1101) of the glue cutting roller (11) are respectively rotatably mounted on a pair of symmetrical glue amount fine-tuning mechanisms. The lower part of the glue coating roller (10) is immersed in the glue liquid in the glue tank (12). The upper preheating roller and the lower preheating roller are both electromagnetic induction heating round rollers; An upper guide adjustment wheel (2) is provided at the lower left of the upper preheating roller, and a lower guide adjustment wheel (6) is provided at the upper left of the lower preheating roller. The upper guide adjustment wheel (2) is located directly above the lower guide adjustment wheel (6). Both the upper guide adjustment wheel (2) and the lower guide adjustment wheel (6) are movably connected to a tension adjustment mechanism provided in the frame (1). The tension adjustment mechanism is used to simultaneously adjust the positions of the upper guide adjustment wheel (2) and the lower guide adjustment wheel (6). A facial paper guide wheel (8) is provided between the lower preheating roller and the pressure roller (9) in the facial paper conveying direction; The glue amount fine-tuning mechanism comprises a second electric push rod (21), a bearing seat (18), a support (19), and a guide rail (20); the support (19) is installed in the frame (1); the dovetail-shaped guide rail (20) is fixed to the top of the support (19); a slide groove (1407) matching the guide rail (20) is provided at the bottom of the bearing seat (18); the rotating shafts at both ends of the roller body (1101) of the rubber cutting roller (11) are rotatably installed in the bearing seat (18); the second electric push rod (21) is fixed on the support (19), and its movable end is connected to the left side of the bearing seat (18); The invention also includes an air blowing and sucking mechanism, which includes a shell (22), the shell (22) including a guide curved surface (22a) in sliding contact with the lower right side of the upper corrugating roller (4), a sealing curved surface (22b) in sliding contact with the upper right side of the lower corrugating roller (5), and a separation curved surface (22c) in sliding contact with the lower right side of the lower corrugating roller (5). An air pump (23) is provided in the shell (22), the air inlet end of the air inlet pipe of the air pump (23) is located at the connection between the guide curved surface (22a) and the sealing curved surface (22b), and the air outlet end of the air outlet pipe of the air pump (23) is located at the connection between the sealing curved surface (22b) and the separation curved surface (22c).

2. The corrugated cardboard single-facer according to claim 1, characterized in that: The lower corrugating roller (5) adopts electromagnetic induction heating corrugating roller.

3. The corrugated cardboard single-facer according to claim 1, characterized in that: The rubber cutting knife (1102) comprises a knife head (1102a) and a blade body (1102b), wherein an angle β exists between the central axis of the blade body (1102b) and the radial direction of the rubber cutting roller (11), and β is between 0° and 30°, and the knife head (1102a) is an outward convex arc.

4. The corrugated cardboard single-facer according to claim 3, characterized in that: The width of the blade head portion (1102a) is greater than the width of the blade body portion (1102b).

5. The corrugated cardboard single-facer according to claim 1, characterized in that: The tension adjustment mechanism comprises an upper adjustment arm (14), a lower adjustment arm (15), a double-sided rack (16), and a first electric push rod (17) which are symmetrically arranged. The first electric push rod (17) and the double-sided rack (16) are both arranged horizontally. The bottom of the first electric push rod (17) is fixed on the frame (1), and its movable end is fixedly connected to one end of the double-sided rack (16). The upper adjustment arm (14) comprises a collar (1401), a first connecting rod (1402), a cylinder (1403), a second connecting rod (1404), and a gear (1405). The collar (1401) is rotatably sleeved on the rotating shaft of the upper guide adjustment wheel (2). One end of the first connecting rod (1402) is connected to the collar (1401), and the other end extends into the cylinder (1403) and is connected to the slider (1406). The cylinder ( A plurality of dovetail groove-shaped slides (1407) are provided on the circumference of the inner wall of the cylinder (1403), a plurality of guide bars matching the slides (1407) are provided on the outer circumference of the slider (1406), a spring (1408) is provided between the slider (1406) and the bottom surface of the cylinder (1403), a second connecting rod (1404) is provided on the outer side of the bottom surface of the cylinder (1403), a gear (1405) is provided on the second connecting rod (1404), the gear (1405) is engaged with the teeth on the double-sided rack (16), a through hole (1409) is provided on one end of the second connecting rod (1404) close to the gear (1405), the second connecting rod (1404) is rotatably connected to the corresponding mounting shaft provided on the frame (1) through the through hole (1409), and the structure of the lower adjusting arm (15) is the same as that of the upper adjusting arm (14).

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