CN116330815B - Packaging box printing machine - Google Patents

Abstract

The application relates to the technical field of packaging box printers, in particular to a packaging box printer which comprises a frame, wherein a conveying part for conveying packaging box paper is arranged on the frame, a printing assembly is arranged on the frame, the printing assembly comprises a pushing part and a printing plate for printing the packaging box paper, the pushing part is arranged on the frame and is spaced from the conveying part, the output end of the pushing part is connected with the printing plate for driving the printing plate to move, a mounting frame is arranged on the frame, a pressing rod for fixing the packaging box paper is arranged in the mounting frame, and the mounting frame slides on the frame along the direction facing the conveying part and is used for driving the pressing rod to abut against the packaging box paper. The application has the effect of improving the printing quality.

Description

Packaging box printing machine

Technical Field

The application relates to the technical field of packaging box printers, in particular to a packaging box printer.

Background

Packaging box printers are devices used to produce packaging boxes, and generally include processes such as board filling, inking, embossing, and paper feeding.

The structure of the packaging box printer in the related art comprises a frame, a conveyor belt, a lifting mechanism and an ink dyeing mechanism, wherein the conveyor belt is arranged on the frame, the lifting mechanism is arranged on the frame and on one side of the conveyor belt deviating from the ground, the ink dyeing mechanism is arranged on the lifting mechanism, and the position of the ink dyeing mechanism is adjusted through the lifting mechanism. When in printing, the packaging box is placed on the conveyor belt to be conveyed, and when the packaging box is conveyed to the ink dyeing mechanism, the ink dyeing mechanism is pushed to the packaging box through the lifting mechanism to be printed.

In the related art, when the lifting mechanism drives the ink dyeing mechanism to dye ink, the packing box is easy to deviate, and the printing quality is affected.

Disclosure of Invention

In order to improve printing quality, the application provides a packaging box printing machine.

The application provides a packaging box printing machine which adopts the following technical scheme:

The utility model provides a packing carton printing machine, includes the frame, be provided with the conveyer that is used for conveying packing carton paper in the frame, be provided with the printing unit in the frame, the printing unit includes the propelling movement piece and is used for the printing plate to packing carton paper printing, the propelling movement piece sets up with the conveyer interval in the frame, the output of propelling movement piece is connected with the printing plate and is used for driving the printing plate and remove, be provided with the installing frame in the frame, be provided with the depression bar that is used for fixed packing carton paper in the installing frame, the installing frame slides along the direction towards the conveyer in the frame and is used for driving depression bar and packing carton paper butt.

Through adopting above-mentioned technical scheme, when conveying piece drove packing carton paper and remove to printing plate department, sliding mounting frame, the while installation frame drive the depression bar remove to with packing carton paper butt, then the propelling movement piece drive printing plate remove to packing carton paper department and print it, fix the position of packing carton paper through the depression bar when printing, reduce when printing, the phenomenon that skew appears in packing carton paper, promote print quality.

Optionally, the installing frame and the depression bar are provided with two sets of side by side in the frame, set up the guiding groove in the installing frame, the one end of guiding groove is close to another installing frame setting, and the other end is along deviating from the direction slope setting of conveyer, be provided with the guide frame in the guiding groove, the guide frame slides along the direction of guiding groove in the guiding groove and sets up, the depression bar sets up on the guide frame, be provided with the elastic component that is used for driving depression bar and packing carton paper butt in the installing frame.

Through adopting above-mentioned technical scheme, when the installing frame removes, drive two depression bars and packing carton paper butt simultaneously, after depression bar and packing carton paper butt, continue to remove the installing frame, the guide frame removes in the guide way, drives the depression bar simultaneously and removes towards the both sides of packing carton paper, expandes packing carton paper, reduces the phenomenon that appears the fold on the packing carton paper, further promotes printing quality.

Optionally, the elastic component includes mounting panel, intermediate lever and elastic component, the mounting panel sets up in the installing frame, the intermediate lever sets up along the gliding direction of guide frame, the intermediate lever runs through the mounting panel setting, the intermediate lever slides along its self length direction on the mounting panel and sets up, the tip and the guide frame of intermediate lever are connected, the elastic component sets up in the mounting panel side, elastic component and intermediate lever are connected and are used for driving the intermediate lever and slide towards the direction of depression bar.

Through adopting above-mentioned technical scheme, drive the intermediate lever and remove when the guide frame removes, compress the elastic component simultaneously, the elastic component drives the depression bar and removes towards the direction of packing carton paper, and then makes the depression bar keep in the state of butt with packing carton paper, promotes the stability of packing carton paper.

Optionally, one side that the installing frame deviates from another installing frame is provided with auxiliary rod, auxiliary block and auxiliary sleeve, auxiliary sleeve sets up in the frame, the auxiliary block slides along vertical direction in auxiliary sleeve and sets up, auxiliary rod and auxiliary block are connected, the tip and the installing frame of auxiliary rod are connected, be provided with the auxiliary member that is used for adjusting auxiliary rod position in the auxiliary sleeve, two be provided with the board of accepting between the installing frame, the output of propelling movement piece runs through and accepts board and printing board and connect, the output of propelling movement piece with accept board sliding connection, be provided with the butt piece on the board of accepting, the butt piece is used for driving the installing frame and removes towards the direction of conveyer, the elasticity of butt piece is greater than the elasticity of auxiliary member.

Through adopting above-mentioned technical scheme, the propelling movement piece drives installing frame and printing plate simultaneously and removes, sets up the elasticity of butt spare and is greater than the elasticity of auxiliary member for after depression bar and packing carton paper butt completely, the printing plate prints with packing carton paper butt thereupon, promotes printing efficiency.

Optionally, the auxiliary rod deviates from the one end of installing frame and runs through auxiliary block setting, auxiliary rod sets up along horizontal direction slip on auxiliary block, accept board and installing frame sliding connection, it sets up along the length direction of auxiliary rod to accept the slip direction of board on the installing frame.

Through adopting above-mentioned technical scheme, set up auxiliary rod and auxiliary block sliding connection, adjust the position of auxiliary rod according to the packing carton paper of different specifications, and then adjust the initial interval between two depression bars through the installing frame, and then adjust the depression bar and complete and packing carton paper interval after the butt to be applicable to the packing carton paper printing of different specifications.

Optionally, be provided with adjusting device on the auxiliary block, adjusting device includes hand wheel, locating part and adjusting gear, the opening has been seted up to the one end that the auxiliary block deviates from auxiliary sleeve, tooth's socket has been seted up along its length direction on the auxiliary rod, adjusting gear rotates the setting on the auxiliary block, adjusting gear passes opening and tooth's socket meshing, the hand wheel rotates the setting on the auxiliary block, the hand wheel is connected with the locating part, the hand wheel passes through locating part and adjusting gear connection.

Through adopting above-mentioned technical scheme, rotate the hand wheel, the hand wheel passes through the locating part and drives adjusting gear and rotate, and adjusting gear rotates and drives the auxiliary rod and remove to adjust the position of installing frame.

Optionally, adjusting device sets up on one of them installing frame, two the same side of installing frame all is provided with the rack bar, two rack bar parallel interval sets up, the rack bar sets up along the slip direction of auxiliary rod, it is provided with the pinion to rotate in the frame, the pinion sets up between two rack bar, pinion simultaneously with two rack bar meshing.

Through adopting above-mentioned technical scheme, when one of them installing frame removes, drive another installing frame synchronous motion through rack and synchronous gear for the distance that two installing frames removed is the same, and adjusts the position of two installing frames simultaneously, promotes adjustment efficiency.

Optionally, the locating part includes worm wheel and worm, worm wheel and worm all rotate the setting on the auxiliary block, worm wheel and adjusting gear coaxial coupling, worm and worm wheel meshing, hand wheel and worm coaxial coupling.

Through adopting above-mentioned technical scheme, rotate the hand wheel, the hand wheel passes through the worm and drives the worm wheel and rotate, and the worm wheel rotates and drives adjusting gear and rotate, adjusts the position of auxiliary rod, and worm wheel and worm cooperation have the auto-lock nature simultaneously, promote the stability of installing the frame after the position control to the installing frame.

Optionally, two guide grooves are formed in the mounting frame, the two guide grooves are formed in the same plane, the end part of the compression bar is close to the guide grooves, the mounting plate and the compression bar are arranged at intervals in parallel, and the middle bar is connected with the center of the mounting plate.

Through adopting above-mentioned technical scheme, the guide slot sets up two sets of, and sets up the center department setting that the middle pole is close to the mounting panel for guide frame is stable removes in the guide slot, and then makes the depression bar steadily remove.

In summary, the present application includes at least one of the following beneficial technical effects:

1. When packing carton paper removes to printing plate department, the propelling movement piece drives the printing plate and removes, when the printing plate does not remove packing carton paper department, drives the installing frame and removes for depression bar and packing carton paper butt, the depression bar removes and expands in the guide way through the guide frame simultaneously, expands packing carton paper and compresses tightly, and the printing plate continues to remove and prints packing carton paper, restricts the position of packing carton paper through the depression bar, and the phenomenon that skew appears in packing carton paper when reducing the printing, and then promotes printing quality.

Drawings

Fig. 1 is a schematic view of a packing box printer according to an embodiment of the present application.

Fig. 2 is another view of a packing box printer according to an embodiment of the present application.

Fig. 3 is a partial view of a packing box printer according to an embodiment of the present application.

Fig. 4 is a structural view of an elastic member in the packing box printer according to the embodiment of the present application.

Fig. 5 is a structural view of the abutment in the packing box printer according to the embodiment of the present application.

Fig. 6 is an enlarged view at a in fig. 5.

Fig. 7 is a structural view of an adjusting device in a packing box printer according to an embodiment of the present application.

Fig. 8 is a structural view showing that the pressing bar moves to the other end of the guide groove in the packing box printer according to the embodiment of the present application.

Reference numerals: 1. a frame; 11. a transfer member; 2. a printing assembly; 21. a pushing member; 22. a printing plate; 3. a limit component; 31. a mounting frame; 32. a compression bar; 4. a guide groove; 41. a guide frame; 5. an elastic component; 51. a mounting plate; 52. an intermediate lever; 53. an elastic member; 6. an auxiliary lever; 61. an auxiliary block; 611. a through port; 62. an auxiliary sleeve; 63. tooth slots; 7. an auxiliary member; 71. a receiving plate; 72. an abutment; 8. an adjusting device; 81. a hand wheel; 82. a limiting piece; 821. a worm wheel; 822. a worm; 83. an adjusting gear; 9. a synchronous rack; 91. and synchronizing the gears.

Detailed Description

The application is described in further detail below with reference to fig. 1-8.

The application discloses a packaging box printing machine. Referring to fig. 1 and 2, the packing box printer includes a frame 1, a transfer member 11 is provided on the frame 1, the transfer member 11 may be provided as a belt conveyor for conveying packing box paper, a printing assembly 2 is provided on the frame 1, the printing assembly 2 includes a pushing member 21 and a printing plate 22, the pushing member 21 may be provided as a cylinder and is provided on the frame 1, and the printing plate 22 is provided at an output end of the pushing member 21 for printing the packing box. When the conveying part 11 drives the packing box paper to be conveyed to the pushing part 21, the printing plate 22 is driven to abut against the packing box paper to print the packing box paper, and after printing is finished, the packing box paper is folded into a packing box by installing folds.

Referring to fig. 3 and 4, a limit assembly 3 is provided on the frame 1, the limit assembly 3 includes a mounting frame 31 and a pressing rod 32, the mounting frame 31 is provided between the pushing member 21 and the conveying member 11, the pressing rod 32 is provided in the mounting frame 31, and the mounting frame 31 is slidably provided on the frame 1 in a direction toward the conveying member 11. After the packing box paper moves to the pushing piece 21, the mounting frame 31 is moved towards the packing box, the mounting frame 31 moves to drive the pressing rod 32 to be abutted against the packing box paper, the packing box paper is fixed, then the printing plate 22 is moved to print the packing box paper, and the phenomenon that the packing box paper is deviated during printing is reduced.

Referring to fig. 3 and 4, the limiting members 3 are provided with two sets, and the two sets of limiting members 3 are arranged along a conveying direction perpendicular to the conveying member 11, the guide groove 4 is provided in the mounting frame 31, the guide frame 41 is provided in the guide groove 4, one end of the guide groove 4 is provided close to the other mounting frame 31, the other end is obliquely provided along a direction away from the conveying member 11, the guide frame 41 is slidably provided in the guide groove 4 along a length direction of the guide groove 4, the compression bar 32 is provided on the guide frame 41, and the compression bar 32 and the guide frame 41 are welded and fixed, the elastic member 5 is provided in the mounting frame 31, and the elastic member 5 and the guide frame 41 are connected to drive the guide frame 41 to slide along a direction toward the other mounting frame 31. In combination with fig. 8, in the initial state, two pressing rods 32 are close to each other, the mounting frame 31 is moved, the mounting frame 31 drives the pressing rods 32 to abut against the center of the packing paper, the mounting frame 31 is continuously moved, the pressing rods 32 drive the guide frame 41 to move in the guide groove 4, meanwhile, the pressing rods 32 are driven to move, the packing paper is placed on the conveying member 11 smoothly by the two pressing rods 32, until the pressing rods 32 move to the edge of the packing paper, then printing is performed through the printing plate 22, the phenomenon that wrinkles appear on the surface of the packing paper during printing is reduced by arranging the pressing rods 32, and the printing effect is further improved.

Referring to fig. 3 and 4, the elastic assembly 5 includes a mounting plate 51, an intermediate lever 52 and an elastic member 53, the mounting plate 51 is disposed in the mounting frame 31, and the intermediate lever 52 is slidably disposed on the mounting plate 51 along the length direction of the guide groove 4, one end of the intermediate lever 52 is connected with the guide frame 41, the other end is disposed through the mounting plate 51, the elastic member 53 may be disposed as a spring disposed on a side of the mounting plate 51 facing away from the pressing lever 32, and the spring is sleeved outside the intermediate lever 52, one end of the spring is connected with the mounting plate 51, and the other end is connected with an end of the intermediate lever 52. That is, when the pressing rod 32 moves, the middle rod 52 is driven to move, and the spring is stretched, so that the pressing rod 32 and the packing paper are kept in an abutting state, and the stability of the packing paper is improved.

Referring to fig. 3 and 4, two guide grooves 4 are provided in the mounting frame 31, and the two guide grooves 4 are disposed in the same plane, two ends of the pressing bar 32 are disposed near the two guide grooves 4, the pressing bar 32 is disposed along the direction in which the conveying member 11 conveys the packing box, the mounting plate 51 and the pressing bar 32 are disposed at parallel intervals, and the intermediate bar 52 is connected to the center of the mounting plate 51. By providing two guide grooves 4, the stability of the pressing lever 32 at the time of movement is improved.

Referring to fig. 5 and 6, an auxiliary lever 6, an auxiliary block 61 and an auxiliary sleeve 62 are provided at a side of the mounting frame 31 facing away from the other mounting frame 31, the auxiliary sleeve 62 is provided on the frame 1, the auxiliary block 61 is slidably provided in the auxiliary sleeve 62 in a vertical direction, an auxiliary member 7 is provided in the auxiliary sleeve 62, the auxiliary member 7 may be provided as a spring, one end of the spring is abutted against an inner wall of the auxiliary sleeve 62, the other end is connected with the auxiliary block 61, a receiving plate 71 is provided between the two mounting frames 31, an output end of the pushing member 21 is connected with the printing plate 22 through the receiving plate 71, an abutment member 72 is provided at a side of the receiving plate 71 facing away from the mounting frame 31, the abutment member 72 may be provided as a spring, one end of the spring is connected with the receiving plate 71, the other end is connected with an output end of the pushing member 21, and an elastic force of the abutment member 72 is larger than that of the auxiliary member 7. The pushing piece 21 drives the mounting frame 31 to move through the abutting piece 72 and the bearing plate 71, meanwhile, the auxiliary piece 7 is compressed, after the compression rod 32 is completely abutted against the packing paper, the mounting frame 31 stops moving, the pushing piece 21 continues to work and compresses the abutting piece 72, and meanwhile, the printing plate 22 is driven to move to the packing paper for printing.

Referring to fig. 5 and 7, an end of the auxiliary lever 6 facing away from the mounting frame 31 is provided through the auxiliary block 61, and the auxiliary lever 6 is slidably provided on the auxiliary block 61 in the horizontal direction. Before printing, the auxiliary rod 6 can be slid according to the size of the packaging paper box, so that the position of the mounting frame 31 can be adjusted, and the initial distance between the two pressing rods 32 can be adjusted, so that the printing device is suitable for printing packaging paper with different specifications. The receiving plate 71 is slidably connected with the mounting frame 31, and the receiving plate 71 is arranged along the length direction of the auxiliary rod 6 relative to the sliding direction of the mounting frame 31, so that when the mounting frame 31 moves, the receiving plate 71 moves on the mounting frame 31, and the overall stability is improved.

Referring to fig. 6 and 7, the adjusting device 8 is provided on the auxiliary block 61, the adjusting device 8 includes a hand wheel 81, a limiting member 82 and an adjusting gear 83, a through hole 611 is provided at one end of the auxiliary block 61 facing away from the auxiliary sleeve 62, a tooth slot 63 is provided on one side of the auxiliary rod 6 near the through hole 611 along the length direction thereof, the adjusting gear 83 is provided at the end of the auxiliary block 61, and is rotatably provided at the end of the auxiliary block 61, the side surface of the adjusting gear 83 is engaged with the tooth slot 63 through the through hole 611, the hand wheel 81 is rotatably provided on the auxiliary block 61, and the hand wheel 81 and the adjusting gear 83 are connected through the limiting member 82. When the position of the mounting frame 31 needs to be adjusted, the hand wheel 81 is rotated, the adjusting gear 83 is driven to rotate through the limiting piece 82, and the adjusting gear 83 is rotated to drive the auxiliary rod 6 to move, so that the position of the mounting frame 31 is adjusted.

Referring to fig. 7, the stopper 82 includes a worm wheel 821 and a worm 822, both of which are rotatably provided on the auxiliary block 61, the worm wheel 821 and the adjusting gear 83 are coaxially connected, the hand wheel 81 and the worm 822 are connected, and the rotation axis of the hand wheel 81 and the rotation axis of the worm 822 are provided on the same line, and the worm wheel and the worm 822 are engaged. The hand wheel 81 drives the adjusting gear 83 to rotate through the worm 822 and the worm wheel 821, and the worm wheel 821 and the worm 822 are matched to have self-locking performance, so that the stability of the mounting frame 31 is improved.

Referring to fig. 5 and 6, the adjusting device 8 is disposed on one of the mounting frames 31, the rack bars 9 are disposed on the side surfaces of the mounting frames 31, the rack bars 9 are disposed on the same side of the two mounting frames 31, and the two rack bars 9 are disposed at intervals in parallel, the rack bars 9 are disposed along the sliding direction of the mounting frames 31, the rack 1 is rotatably provided with a rack gear 91, the rack gear 91 is disposed between the two rack bars 9, and the rack gear 91 is engaged with the rack bars 9. When the adjusting device 8 drives one of the mounting frames 31 to move, the other mounting frame 31 is driven to synchronously move through the synchronous rack 9 and the gear, so that the moving distances of the two mounting frames 31 are the same, and the adjusting efficiency of the mounting frames 31 is improved.

The implementation principle of the application is as follows: during printing, the pushing piece 21 drives the pressing rod 32 to move, meanwhile, the guide frame 41 moves in the guide groove 4, drives the pressing rod 32 to move while abutting against the packing box paper, expands and compresses the packing box paper, then the pushing piece 21 drives the printing plate 22 to move for printing, the phenomenon that the packing box paper shifts is reduced, and the printing quality is improved.

The above embodiments are not intended to limit the scope of the present application, so: all equivalent changes in structure, shape and principle of the application should be covered in the scope of protection of the application.

Claims (2)

1. Packaging box printing machine, comprising a frame (1), characterized in that: the machine frame is characterized in that a conveying piece (11) for conveying packaging box paper is arranged on the machine frame (1), a printing component (2) is arranged on the machine frame (1), the printing component (2) comprises a pushing piece (21) and a printing plate (22) for printing the packaging box paper, the pushing piece (21) is arranged on the machine frame (1) at intervals with the conveying piece (11), an output end of the pushing piece (21) is connected with the printing plate (22) and used for driving the printing plate (22) to move, a mounting frame (31) is arranged on the machine frame (1), a pressing rod (32) for fixing the packaging box paper is arranged in the mounting frame (31), the mounting frame (31) slides on the frame (1) along the direction facing the conveying piece (11) and is used for driving the compression bar (32) to abut against packing paper, the mounting frame (31) and the compression bar (32) are arranged on the frame (1) in parallel, two groups of guide grooves (4) are formed in the mounting frame (31), one end of each guide groove (4) is close to the other mounting frame (31), the other end of each guide groove is obliquely arranged along the direction facing away from the conveying piece (11), a guide frame (41) is arranged in each guide groove (4), the guide frame (41) slides in the guide grooves (4) along the direction of each guide groove (4), the compression bar (32) is arranged on each guide frame (41), an elastic component (5) used for driving a compression bar (32) to abut against packing box paper is arranged in the mounting frame (31), the elastic component (5) comprises a mounting plate (51), a middle rod (52) and an elastic piece (53), the mounting plate (51) is arranged in the mounting frame (31), the middle rod (52) is arranged along the sliding direction of the guide frame (41), the middle rod (52) penetrates through the mounting plate (51), the middle rod (52) is arranged on the mounting plate (51) in a sliding mode along the length direction of the middle rod, the end portion of the middle rod (52) is connected with the guide frame (41), the elastic piece (53) is arranged on the side face of the mounting plate (51), the elastic piece (53) is connected with the middle rod (52) and is used for driving the middle rod (52) to slide towards the direction of the compression bar (32), one side of the installation frame (31) deviating from the other installation frame (31) is provided with an auxiliary rod (6), an auxiliary block (61) and an auxiliary sleeve (62), the auxiliary sleeve (62) is arranged on the frame (1), the auxiliary block (61) is arranged in the auxiliary sleeve (62) in a sliding way along the vertical direction, the auxiliary rod (6) is connected with the auxiliary block (61), the end part of the auxiliary rod (6) is connected with the installation frame (31), an auxiliary piece (7) for adjusting the position of the auxiliary rod (6) is arranged in the auxiliary sleeve (62), a bearing plate (71) is arranged between the two mounting frames (31), the output end of the pushing piece (21) penetrates through the bearing plate (71) and is connected with the printing plate (22), the output end of the pushing piece (21) is in sliding connection with the bearing plate (71), an abutting piece (72) is arranged on the bearing plate (71), the abutting piece (72) is used for driving the mounting frames (31) to move towards the direction of the conveying piece (11), the elastic force of the abutting piece (72) is larger than that of the auxiliary piece (7), one end of the auxiliary rod (6) deviating from the mounting frames (31) penetrates through the auxiliary block (61) and is arranged on the auxiliary block (61) in a sliding mode along the horizontal direction, the bearing plate (71) is in sliding connection with the mounting frame (31), the sliding direction of the bearing plate (71) on the mounting frame (31) is set along the length direction of the auxiliary rod (6), the auxiliary block (61) is provided with an adjusting device (8), the adjusting device (8) comprises a hand wheel (81), a limiting piece (82) and an adjusting gear (83), one end of the auxiliary block (61) deviating from the auxiliary sleeve (62) is provided with a through hole (611), the auxiliary rod (6) is provided with a tooth socket (63) along the length direction thereof, the adjusting gear (83) is rotationally arranged on the auxiliary block (61), the adjusting gear (83) is meshed with the tooth socket (63) through the through hole (611), the hand wheel (81) is rotationally arranged on the auxiliary block (61), the hand wheel (81) is connected with the limiting piece (82), the hand wheel (81) is connected with the adjusting gear (83) through the limiting piece (82), the adjusting device (8) is arranged on one of the mounting frames (31), the same side of the two mounting frames (31) is provided with the synchronous racks (9), the two synchronous racks (9) are arranged at intervals in parallel, the synchronous racks (9) are arranged along the sliding direction of the auxiliary rod (6), the synchronous gear (91) is rotationally arranged on the frame (1), the synchronous gear (91) is arranged between the two synchronous racks (9), the synchronous gear (91) is meshed with the two synchronous racks (9) simultaneously, the limiting piece (82) comprises a worm wheel (821) and a worm (822), the worm wheel (821) and the worm (822) are both rotatably arranged on the auxiliary block (61), the worm wheel (821) and the adjusting gear (83) are coaxially connected, the worm (822) is meshed with the worm wheel (821), and the hand wheel (81) is coaxially connected with the worm (822).

2. The package printer according to claim 1, wherein: the guide grooves (4) are formed in the mounting frame (31) in two, the two guide grooves (4) are arranged in the same plane, the end parts of the compression bars (32) are arranged close to the guide grooves (4), the mounting plates (51) and the compression bars (32) are arranged at intervals in parallel, and the middle rods (52) are connected with the center of the mounting plates (51).