Laminating equipment for light-weight corrugated carton

Abstract

The film laminating equipment comprises two bases which are symmetrically arranged front and back, a horizontally-arranged conveyor is rotationally connected between the sides, close to each other, of the two bases, a fixing base is fixedly connected to the left side of the top of each base, and sliding grooves are formed in the front side and the rear side of each fixing base; a first mounting block and a second mounting block are connected to the inner walls of the front sliding groove and the rear sliding groove in an up-down sliding mode, a flattening roller perpendicular to the top of the conveyor is rotationally connected between the sides, close to each other, of the first mounting block and the second mounting block, and a controller is fixedly connected to one side, on the front side, of the base. The equipment has the advantage that a cleaning mechanism is automatically and flexibly adjusted, by integrating efficient cleaning, dust suction and dust collection systems, the product quality is improved, the sanitary condition of the working environment is remarkably improved, and the equipment is very suitable for meeting the production requirement of light-weight corrugated cartons.

Description

Technical Field

[0001] This utility model relates to the field of lamination equipment technology, specifically to a lamination equipment for lightweight corrugated cardboard boxes. Background Technology

[0002] Lightweight corrugated box laminating equipment is mainly used to cover the surface of corrugated boxes with a thin film to enhance their water resistance, moisture resistance and durability.

[0003] Existing corrugated cardboard box laminating equipment can be referenced from Chinese Utility Model Patent Publication No. CN216183087U, which discloses an environmentally friendly waterproof corrugated cardboard box laminating equipment. This equipment includes a base, with a fixed seat fixedly installed on one side of the top of the base. Sliding grooves are formed in the middle of both sides of the fixed seat. A first mounting block and a second mounting block are slidably installed inside the two sliding grooves, respectively. Rotating seats are fixedly installed at the top of both the first and second mounting blocks. This environmentally friendly waterproof corrugated cardboard box laminating equipment uses two knobs to simultaneously rotate two threaded columns, which in turn move the flattening rollers up and down. This allows for flattening of cardboard boxes of different thicknesses. A cleaning brush cleans the surface of the cardboard box to remove dust and foreign objects. An electric exhaust fan generates suction to adsorb dust from the cardboard board surface, preventing dust and foreign objects from remaining and affecting subsequent gluing and laminating effects.

[0004] The above-mentioned device has a good effect, but there are still some defects in its actual use. The cleaning brush and dust collection hopper in the cleaning mechanism of the device are fixed, which is not convenient to adjust flexibly according to different usage needs. Different corrugated boxes may have different sizes, shapes or surface characteristics. The fixed cleaning brush and dust collection hopper cannot be flexibly adjusted in position, making it difficult to adapt to diverse production needs. Utility Model Content

[0005] The purpose of this invention is to provide a laminating device for lightweight corrugated cardboard boxes, which has the advantages of automatic and flexible adjustment of the cleaning mechanism. By integrating a high-efficiency cleaning, dust extraction and dust collection system, it not only improves the quality of the product, but also significantly improves the hygiene conditions of the working environment, making it very suitable for the production needs of lightweight corrugated cardboard boxes.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a lightweight corrugated cardboard box laminating device, comprising two bases symmetrically arranged front and rear, a horizontally arranged conveyor rotatably connected between the two bases on their respective sides, a fixed seat fixedly connected to the top left of each base, and grooves provided on both the front and rear sides of each fixed seat, with a first mounting block and a second mounting block slidably connected to the inner walls of both grooves, and a flattening roller rotatably connected between the first mounting block and the second mounting block on their respective sides, perpendicular to the top of the conveyor, and a controller fixedly connected to one side of the front base.

[0007] A cleaning mechanism is provided on one side of the fixed base, and the cleaning mechanism is located above the top of the conveyor. The cleaning mechanism includes a mounting plate disposed above the top of the conveyor. One side of the mounting plate is fixedly connected to the top of one side of the fixed base. A U-shaped plate is provided on the lower side of the mounting plate near the fixed base. A cleaning roller is rotatably connected to the lower inner wall of the U-shaped plate. A cleaning brush is fixedly sleeved on the surface of the cleaning roller. A lifting rod is fixedly connected to the center of the top of the U-shaped plate. The top of the lifting rod extends to the top of the mounting plate and is slidably connected to it. A dust suction pipe is provided on the side of the U-shaped plate away from the fixed base. Multiple dust suction hoppers are fixedly connected to the bottom of the dust suction pipe at equal intervals.

[0008] As a preferred embodiment of the lightweight corrugated cardboard box laminating equipment of this utility model, an adhesive applicator is fixedly connected to the center of the top of the base, a laminating machine is fixedly connected to the right side of the top of the base, threaded columns are rotatably connected to the top of the first mounting block and the second mounting block, the tops of the two threaded columns extend to the top of the fixed seat and are rotatably connected thereto, a first motor is fixedly connected to the rear side of the first mounting block, and the output shaft of the first motor is fixedly connected to the inner wall of the flattening roller.

[0009] As a preferred embodiment of the lightweight corrugated cardboard box laminating equipment of this utility model, the front and rear ends of the top of the U-shaped plate are fixedly connected with L-shaped rods, and the ends of the L-shaped rods away from the U-shaped plate are respectively fixedly connected to the front and rear ends of the top of the dust suction pipe. A lifting plate is provided above the top of the mounting plate.

[0010] As a preferred embodiment of the lightweight corrugated cardboard box laminating equipment of this utility model, a lifting rod is fixedly connected to the center of the bottom of the lifting plate, a dust collection box is fixedly connected to the rear side of the base, a filter plate is provided inside the upper part of the dust collection box, and a corrugated pipe is fixedly connected to the center of the top of the suction pipe.

[0011] As a preferred embodiment of the lightweight corrugated cardboard box laminating equipment of this utility model, the end of the corrugated pipe away from the dust suction pipe is fixedly connected to one side of the top of the dust collection box, a negative pressure pump is fixedly connected to the other side of the top of the dust collection box, the suction end of the negative pressure pump is fixedly connected to the top of the dust collection box, and the lifting plate is slidably connected to the top of the mounting plate.

[0012] As a preferred embodiment of the lightweight corrugated cardboard box laminating equipment of this utility model, a cleaning door is rotatably connected to one side of the dust collection box, a handle is fixedly connected to one side of the cleaning door, a lifting threaded rod is threadedly connected to the inner wall of the front end of the lifting plate, and a guide rod is slidably connected to the inner wall of the rear end of the lifting plate.

[0013] In a preferred embodiment of the lightweight corrugated cardboard box laminating equipment of this utility model, the bottom of the lifting plate is rotatably connected to the front end of the top of the mounting plate, the bottom of the guide rod is fixedly connected to the rear end of the top of the mounting plate, an L-shaped plate is threadedly connected to the top surface of the lifting threaded rod, and an L-shaped plate is fixedly connected to the top surface of the guide rod.

[0014] As a preferred embodiment of the lightweight corrugated cardboard box laminating equipment of this utility model, the bottoms of the two L-shaped plates are fixedly connected to the front and rear ends of the top of the mounting plate, a second motor is fixedly connected to the top of the front L-shaped plate, the output shaft of the second motor is fixedly connected to the top of the lifting threaded rod, a protective cover is provided outside the second motor, and the bottom of the protective cover is fixedly connected to the top of the front L-shaped plate.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] 1. This utility model can drive the first mounting block and the second mounting block to move up and down by rotating the threaded column. The first motor drives the flattening roller to rotate. By rotating the two threaded columns at the same time, the first mounting block and the second mounting block can move up and down synchronously, thereby adjusting the height of the flattening roller to adapt to corrugated boxes of different thicknesses.

[0017] 2. In this invention, corrugated cardboard boxes enter the equipment via a conveyor. When the boxes reach the cleaning area, the cleaning rollers inside the U-shaped plate drive the cleaning brushes to rotate, removing dust and foreign objects from the surface of the boxes. Simultaneously, a negative pressure pump starts, generating negative pressure in the suction pipe to draw in the dust raised during the cleaning process and send it into the dust collection box through the corrugated pipe. The air entering the dust collection box is filtered by a filter plate before being discharged, while the dust remains inside. Depending on the thickness of the cardboard boxes, a second motor drives the lifting threaded rod to rotate, causing the lifting plate to slide up and down along the guide rod, precisely adjusting the position of the cleaning brushes and the suction hopper. When it is necessary to clean the dust in the dust collection box, the operator can open the cleaning door by the handle to conveniently and quickly complete the dust cleaning work. Attached Figure Description

[0018] Figure 1 This is a three-dimensional drawing of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of the fixing base of this utility model;

[0020] Figure 3 This is a schematic diagram of the cleaning mechanism of this utility model.

[0021] In the diagram: 1. Base; 2. Conveyor; 3. Fixed seat; 4. Cleaning mechanism; 401. Mounting plate; 402. U-shaped plate; 403. Cleaning roller; 404. Cleaning brush; 405. Lifting rod; 406. L-shaped rod; 407. Suction pipe; 408. Suction hopper; 409. Corrugated pipe; 410. Dust collection box; 411. Filter plate; 412. Negative pressure pump; 413. Lifting plate; 414. Lifting threaded rod; 415. Guide rod; 416. L-shaped plate; 417. Second motor; 418. Protective cover; 419. Cleaning door; 420. Handle; 5. Glue applicator; 6. Film applicator; 7. Controller; 8. First motor; 9. First mounting block; 10. Slide groove; 11. Second mounting block; 13. Threaded column; 16. Flattening roller. Detailed Implementation

[0022] Please see Figures 1-3 A lightweight corrugated cardboard box laminating device includes two symmetrically arranged bases 1, with a horizontally arranged conveyor 2 rotatably connected between the two bases 1 on one side of each other. A fixed seat 3 is fixedly connected to the top left side of the base 1. The fixed seat 3 has sliding grooves 10 on both the front and rear sides. A first mounting block 9 and a second mounting block 11 are slidably connected to the inner walls of the two sliding grooves 10. A flattening roller 16, which is perpendicular to the top of the conveyor 2, is rotatably connected between the first mounting block 9 and the second mounting block 11 on one side of each other. A controller 7 is fixedly connected to one side of the front base 1.

[0023] The complete set of equipment consists of two symmetrically arranged bases 1, which are connected by a conveyor 2 to carry and transport corrugated cardboard to be laminated. The base 1 is equipped with a fixed seat 3, which has a sliding groove 10 inside to realize the height adjustment of the flattening roller 16 to adapt to lightweight cartons of different thicknesses. The equipment is also equipped with a controller 7 to facilitate centralized control of the entire operation process, improve the degree of automation and ease of operation.

[0024] Furthermore, a cleaning mechanism 4 is provided on one side of the fixed base 3. The cleaning mechanism 4 is located above the top of the conveyor 2. The cleaning mechanism 4 includes a mounting plate 401 located above the top of the conveyor 2. One side of the mounting plate 401 is fixedly connected to the top of one side of the fixed base 3. A U-shaped plate 402 is provided on the lower side of the mounting plate 401 near the fixed base 3. A cleaning roller 403 is rotatably connected to the lower inner wall of the U-shaped plate 402. A cleaning brush 404 is fixedly sleeved on the surface of the cleaning roller 403. A lifting rod 405 is fixedly connected to the center of the top of the U-shaped plate 402. The top of the lifting rod 405 extends to the top of the mounting plate 401 and is slidably connected to it. A suction pipe 407 is provided on the side of the U-shaped plate 402 away from the fixed base 3. Multiple suction hoppers 408 are fixedly connected to the bottom of the suction pipe 407 at equal intervals.

[0025] The cleaning mechanism 4 is an important component of the equipment, located above the conveyor 2. It is primarily used for pre-treating the surface of the carton before lamination to ensure lamination quality. The mounting plate 401 is horizontally fixed to one side of the fixed base 3. A U-shaped plate 402 is positioned below the mounting plate 401 to support the cleaning roller 403 and the dust collection components. The cleaning roller 403 is rotatably connected to the lower inner wall of the U-shaped plate 402, and a cleaning brush 404 is fixedly mounted on its surface for cleaning dust and foreign objects from the carton surface. A lifting rod 405 is vertically connected to the top center of the U-shaped plate 402 and passes through the mounting plate 401 to form a sliding connection, allowing the cleaning roller 403 to move up and down, thereby adjusting the cleaning height or pressure. A dust collection pipe 407 is located on the side of the U-shaped plate 402 away from the fixed base 3, and multiple dust collection buckets 408 are evenly arranged at the bottom to absorb dust particles raised during the cleaning process, preventing secondary pollution. This equipment not only actively cleans the surface of cartons by rotating the cleaning brush 404, but also collects dust through a dust collection device, effectively ensuring the cleanliness of the laminated surface. The design of the lifting rod 405 allows the cleaning brush 404 to adapt to cartons of different thicknesses or surface conditions, enhancing the applicability of the equipment. The cleaning mechanism 4 is located above the conveying path, so it does not interfere with subsequent gluing and laminating processes, making efficient use of space.

[0026] Furthermore, a glue applicator 5 is fixedly connected to the top center of the base 1, and a film applicator 6 is fixedly connected to the top right side of the base 1. Threaded posts 13 are rotatably connected to the top of the first mounting block 9 and the second mounting block 11. The tops of the two threaded posts 13 extend to the top of the fixed base 3 and are rotatably connected thereto. A first motor 8 is fixedly connected to the rear side of the first mounting block 9. The output shaft of the first motor 8 is fixedly connected to the inner wall of the flattening roller 16.

[0027] Rotating the threaded column 13 can drive the first mounting block 9 and the second mounting block 11 to move up and down. The first motor 8 drives the flattening roller 16 to rotate. By rotating the two threaded columns 13 at the same time, the first mounting block 9 and the second mounting block 11 can move up and down synchronously, thereby adjusting the height of the flattening roller 16 to adapt to corrugated boxes of different thicknesses.

[0028] Furthermore, L-shaped rods 406 are fixedly connected to both the front and rear ends of the top of the U-shaped plate 402. The end of the L-shaped rod 406 away from the U-shaped plate 402 is fixedly connected to the front and rear ends of the top of the suction pipe 407, respectively. A lifting plate 413 is provided above the top of the mounting plate 401.

[0029] L-shaped rods 406 are fixedly connected to both the front and rear ends of the top of the U-shaped plate 402. The end of the L-shaped rod 406 away from the U-shaped plate 402 is fixedly connected to the front and rear ends of the top of the suction pipe 407. This design ensures that the suction pipe 407 can be stably suspended above the cleaning roller 403 while maintaining an appropriate relative position.

[0030] Furthermore, a lifting rod 405 is fixedly connected to the bottom center of the lifting plate 413, a dust collection box 410 is fixedly connected to the rear side of the base 1, a filter plate 411 is provided inside the dust collection box 410, and a corrugated pipe 409 is fixedly connected to the top center of the suction pipe 407.

[0031] A corrugated pipe 409 is fixedly connected to the top center of the suction pipe 407. The corrugated pipe 409 has good extensibility and flexibility, and is suitable for connecting two relatively movable parts. One end of it is connected to the suction pipe 407, and the other end should be connected to the dust collection box 410 at the rear, which is used to transport dust from the cleaning area to the dust collection box 410. The design of the corrugated pipe 409 effectively solves the problem of sealing and continuity of the suction channel during the lifting process, avoiding air leakage or blockage.

[0032] Furthermore, the end of the corrugated pipe 409 away from the suction pipe 407 is fixedly connected to one side of the top of the dust collection box 410, and a negative pressure pump 412 is fixedly connected to the other side of the top of the dust collection box 410. The suction end of the negative pressure pump 412 is fixedly connected to the top of the dust collection box 410, and the lifting plate 413 is slidably connected to the top of the mounting plate 401.

[0033] A negative pressure pump 412 is fixedly connected to the other side of the top of the dust collection box 410. Its suction end is fixedly connected to the top of the dust collection box 410. The negative pressure pump 412 provides the necessary negative pressure for the entire dust collection system, so that dust can be effectively drawn from the surface of the corrugated cardboard box through the suction hopper 408, suction pipe 407, and corrugated pipe 409 into the dust collection box 410. This design ensures that dust will not escape back into the environment, improving the overall dust removal efficiency and environmental performance of the system.

[0034] The lifting plate 413 is connected to the top of the mounting plate 401 by a sliding connection, which means that the lifting plate 413 can move freely in the vertical direction to adapt to corrugated boxes of different thicknesses. By adjusting the height of the lifting plate 413, the position of the cleaning brush 404 and the dust collection bucket 408 can be precisely controlled to ensure that they can effectively act on the surface of boxes of various sizes.

[0035] Furthermore, a cleaning door 419 is rotatably connected to one side of the dust collection box 410, a handle 420 is fixedly connected to one side of the cleaning door 419, a lifting threaded rod 414 is threadedly connected to the inner wall of the front end of the lifting plate 413, and a guide rod 415 is slidably connected to the inner wall of the rear end of the lifting plate 413.

[0036] Through a threaded connection, the lifting threaded rod 414 can precisely control the height adjustment of the lifting plate 413. Rotating the lifting threaded rod 414 allows the lifting plate 413 to move up and down, thereby achieving precise adjustment of the positions of the cleaning brush 404 and the dustbin 408. This design allows users to easily adjust the position of the cleaning mechanism 4 according to the different thicknesses of corrugated cardboard boxes, ensuring the best cleaning effect. The guide rod 415 provides a stable sliding track to prevent the lifting plate 413 from shifting or tilting during adjustment, ensuring its smooth vertical movement. Combined with the threaded lifting threaded rod 414, the guide rod 415 enhances the stability and reliability of the entire height adjustment system.

[0037] Furthermore, the bottom of the lifting plate 413 is rotatably connected to the front end of the top of the mounting plate 401, the bottom of the guide rod 415 is fixedly connected to the rear end of the top of the mounting plate 401, the top surface of the lifting threaded rod 414 is threaded with an L-shaped plate 416, and the top surface of the guide rod 415 is fixedly connected with an L-shaped plate 416.

[0038] Furthermore, the bottoms of the two L-shaped plates 416 are fixedly connected to the front and rear ends of the top of the mounting plate 401. The top of the front L-shaped plate 416 is fixedly connected to the second motor 417. The output shaft of the second motor 417 is fixedly connected to the top of the lifting threaded rod 414. The second motor 417 is provided with a protective cover 418. The bottom of the protective cover 418 is fixedly connected to the top of the front L-shaped plate 416.

[0039] The bottom of the L-shaped plate 416 is fixedly connected to the front and rear ends of the top of the mounting plate 401, serving as the support base for the entire lifting system. The second motor 417 drives the lifting threaded rod 414 to rotate, thereby causing the lifting plate 413 to move up and down, thus controlling the height of the cleaning brush 404 and the dust collection bucket 408. This structure realizes the automatic adjustment function of the cleaning mechanism 4, improving the intelligence level and ease of operation of the equipment. The second motor 417 is equipped with a protective cover 418 to prevent dust from entering or being accidentally touched, ensuring stable operation of the motor and extending its service life.

[0040] Corrugated cardboard boxes enter the equipment via conveyor 2. When the boxes reach the cleaning area, the cleaning roller 403 inside the U-shaped plate 402 drives the cleaning brush 404 to rotate, removing dust and foreign objects from the surface of the boxes. Simultaneously, the negative pressure pump 412 starts, generating negative pressure in the suction pipe 407, sucking in the dust raised during the cleaning process and sending it into the dust collection box 410 through the corrugated pipe 409. The air entering the dust collection box 410 is filtered by the filter plate 411 and then discharged, while the dust remains inside the dust collection box 410. Depending on the thickness of the cardboard boxes, the second motor 417 drives the lifting threaded rod 414 to rotate, causing the lifting plate 413 to slide up and down along the guide rod 415, precisely adjusting the position of the cleaning brush 404 and the suction hopper 408. When it is necessary to clean the dust in the dust collection box 410, the operator can open the cleaning door 419 through the handle 420 to conveniently and quickly complete the dust cleaning work.

[0041] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A film covering equipment for lightweight corrugated cartons, comprising two bases (1) arranged symmetrically front and back, a horizontal conveyor (2) rotatably connected between the two bases (1) on one side close to each other, a fixed seat (3) fixedly connected to the left top of the base (1), a sliding groove (10) formed on the front and back of the fixed seat (3), a first mounting block (9) and a second mounting block (11) slidably connected to the inner wall of the sliding groove (10) on the top and bottom, a flattening roller (16) rotatably connected between the first mounting block (9) and the second mounting block (11) on one side close to each other and vertically arranged on the top of the conveyor (2), a controller (7) fixedly connected to one side of the base (1) on the front side, characterized in that: a cleaning mechanism (4) is arranged on one side of the fixed seat (3), the cleaning mechanism (4) is located above the top of the conveyor (2), the cleaning mechanism (4) comprises a mounting plate (401) arranged above the top of the conveyor (2), the mounting plate (401) is fixedly connected between the top of one side of the fixed seat (3) and one side, a U-shaped plate (402) is arranged below one side of the fixed seat (3) close to the mounting plate (401), a cleaning roller (403) is rotatably connected to the inner wall below the U-shaped plate (402), a cleaning brush (404) is fixedly sleeved on the surface of the cleaning roller (403), a lifting rod (405) is fixedly connected to the top center of the U-shaped plate (402), the lifting rod (405) extends to above the top of the mounting plate (401) and is slidably connected thereto, a dust suction pipe (407) is arranged on the side away from the fixed seat (3) of the U-shaped plate (402), and a plurality of dust suction hoppers (408) are fixedly connected to the bottom of the dust suction pipe (407).

2. The film laminating apparatus for a lightweight corrugated carton according to claim 1, characterized by: A gluing machine (5) is fixedly connected to the top center of the base (1), a film laminating machine (6) is fixedly connected to the right top of the base (1), threaded columns (13) are rotatably connected to the top of the first mounting block (9) and the second mounting block (11), the threaded columns (13) extend to above the top of the fixed seat (3) and are rotatably connected thereto, a first motor (8) is fixedly connected to the rear side of the first mounting block (9), and the output shaft of the first motor (8) is fixedly connected between the inner wall of the flattening roller (16).

3. The film laminating apparatus for a lightweight corrugated carton according to claim 1, characterized in that: L-shaped rods (406) are fixedly connected to the top front and back of the U-shaped plate (402), the L-shaped rods (406) are fixedly connected between the top front and back of the dust suction pipe (407) away from the U-shaped plate (402), respectively, and a lifting plate (413) is arranged above the top of the mounting plate (401).

4. The film laminating apparatus for a lightweight corrugated carton according to claim 3, characterized by: A lifting rod (405) is fixedly connected to the bottom center of the lifting plate (413), a dust collection box (410) is fixedly connected to the rear side of the base (1), a filter plate (411) is arranged inside the dust collection box (410), and a corrugated pipe (409) is fixedly connected to the top center of the dust suction pipe (407).

5. The film laminating apparatus for a lightweight corrugated carton according to claim 4, characterized by: The corrugated pipe (409) is fixedly connected between one end away from the dust collection pipe (407) and one side of the top of the dust collecting box (410), one side of the top of the dust collecting box (410) is fixedly connected with a negative pressure pump (412), the suction end of the negative pressure pump (412) is fixedly connected with the top of the dust collecting box (410), and the lifting plate (413) is slidingly connected with the top of the mounting plate (401).

6. The film laminating apparatus for a lightweight corrugated carton according to claim 5, characterized by: One side of the dust collecting box (410) is rotatably connected with a cleaning door (419), one side surface of the cleaning door (419) is fixedly connected with a handle (420), the inner wall of the front end of the lifting plate (413) is threadedly connected with a lifting threaded rod (414), and the inner wall of the rear end of the lifting plate (413) is slidingly connected with a guide rod (415).

7. The film laminating apparatus for a lightweight corrugated carton according to claim 6, characterized by: The bottom of the lifting plate (413) is rotatably connected with the front end of the top of the mounting plate (401), the bottom of the guide rod (415) is fixedly connected with the rear end of the top of the mounting plate (401), the top surface of the lifting threaded rod (414) is threadedly connected with an L-shaped plate (416), and the top surface of the guide rod (415) is fixedly connected with the L-shaped plate (416).

8. The film laminating apparatus for a lightweight corrugated carton according to claim 7, characterized by: The bottoms of two L-shaped plates (416) are fixedly connected between the front and rear ends of the top of the mounting plate (401), the top of the L-shaped plate (416) at the front end is fixedly connected with a second motor (417), the output shaft of the second motor (417) is fixedly connected with the top of the lifting threaded rod (414), the second motor (417) is externally provided with a protective cover (418), and the bottom of the protective cover (418) is fixedly connected with the top of the L-shaped plate (416) at the front end.

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