A modified structure and construction process of a hatch cover

Abstract

The present invention relates to the technical field of ship auxiliary machinery, and in particular to a modification structure and construction process of a hatch cover. The hatch cover comprises a hollow coaming, a cover plate arranged at the end portion of the hollow coaming, and a hinge device connected between one side of the cover plate and one side of the hollow coaming; the hollow coaming comprises four plane coamings connected together, and a circular arc coaming is transitionally connected between two adjacent plane coamings; the modification structure of the hatch cover comprises a pair of balancing cantilevers connected to the cover, one end of the balancing cantilever is connected to the side of the cover close to the hinge device, and the other end of the balancing cantilever extends toward a side away from the center position of the cover, and a balancing block is connected between the cantilever ends of the pair of balancing cantilevers. The present invention facilitates the opening and closing of the cover, and improves the quality of the butt welding between the hatch cover and the hatch deck of the ship.

Description

Technical Field

[0001] The present invention relates to the technical field of ship auxiliary machinery, and in particular to a modification structure and construction process of a hatch cover. Background Art

[0002] A large refrigerated container ship is equipped with a small hatch cover. The small hatch cover consists of a coaming, a cover plate installed at the end of the coaming, a hinge device connecting the coaming and the cover plate, and a central linkage opening device installed between the center of the cover plate and the coaming. The above-mentioned small hatch cover has the following problems when used:

[0003] Firstly, the cover with a central linkage opening device is heavy in overall weight, which results in a large opening force and makes opening more difficult.

[0004] Secondly, the small hatch cover is generally manufactured as a whole and then installed on the hatch position of the ship's deck and fixed by welding. However, the deck plane of the hatch position itself may have certain unevenness due to its manufacturing errors. In addition, the small hatch cover's panel also needs to be welded during manufacturing, and the lower end of the panel is also uneven. This causes a large uneven gap to appear when the lower end of the panel of the small hatch cover is assembled and docked with the deck plane of the hatch position. This may cause welding defects and uneven welding stress, resulting in a decrease in the sealing reliability after welding. For this reason, the existing technology often uses a method of manually grinding and trimming the lower end of the panel to improve the quality of its docking welding. However, the conventional grinding and trimming method is inefficient and requires repeated trial assembly and repeated grinding. The workload is large and the quality of grinding and trimming is difficult to guarantee. Summary of the Invention

[0005] To address the above issues, the present invention proposes a hatch cover modification structure and construction process, aiming to facilitate the opening and closing of the cover and improve the quality of the butt welding between the hatch cover and the ship's hatch deck. The specific technical solution is as follows:

[0006] A modified structure for a hatch cover, the hatch cover comprising a hollow coaming, a cover plate arranged at an end portion of the hollow coaming, and a hinge device connected between one side of the cover plate and one side of the hollow coaming; the hollow coaming comprises four planar coamings connected together, and a circular arc coaming is transitionally connected between two adjacent planar coamings; the modified structure for the hatch cover comprises a pair of balancing cantilevers connected to the cover, one end of the balancing cantilever is connected to a side of the cover close to the hinge device, and the other end of the balancing cantilever extends toward a side away from the center position of the cover, and a balancing block is connected between the cantilever ends of the pair of balancing cantilevers.

[0007] Preferably, the balancing weight includes a first balancing weight connected between the cantilever ends of the pair of balancing cantilevers and a second balancing weight connected to the first balancing weight.

[0008] In the present invention, the hatch cover further comprises a central linkage opening device arranged at the center position of the cover plate.

[0009] A construction process for a modified structure of a hatch cover comprises the following steps:

[0010] (1) Preparation of balancing cantilever and balancing weight: Prepare a pair of balancing cantilever and balancing weight;

[0011] (2) Hatch cover modification: weld a pair of balancing arms to the cover plate, and weld a balancing block between the cantilever ends of the pair of balancing arms;

[0012] (3) Trial assembly and repair of hatch covers: hoist the hatch cover assembly onto the deck where the hatch is opened, check the contact between the lower end face of the hollow coaming and the deck surface. If poor contact is found, lift and fix the hollow coaming and then grind its lower end face to ensure that the lower end face of the hollow coaming can fully contact with the deck surface after assembly;

[0013] (4) Formal assembly and welding of the hatch cover: After the lower end surface of the hollow coaming is ground into place, the hollow coaming is repositioned on the deck surface with the hatch, and the lower end of the hollow coaming is welded to the deck surface.

[0014] In the process of trial installation and repair of the hatch cover in step (3), the hatch cover is lifted and fixed as a whole by using a hatch cover lifting and fixing tool, and then the lower end surface of the hollow coaming is ground by using a push-pull type automatic grinding device;

[0015] The push-pull automatic grinding device includes a push-pull positioning seat horizontally arranged on the deck surface, a push-pull handle connected to the push-pull positioning seat, and a grinding component vertically arranged on the push-pull positioning seat, the lower end of the grinding component is provided with a roller in contact with the deck surface below the hollow coaming, and the upper end of the grinding component is provided with a grinding wheel driven by a motor for grinding the lower end surface of the hollow coaming;

[0016] Preferably, the motor is an electric motor or a pneumatic motor.

[0017] As a preferred solution of the push-pull type automatic grinding device in the present invention, the lower end of the push-pull positioning seat is provided with a cavity upward, the grinding component includes a grinding wheel assembly arranged on the upper part of the push-pull positioning seat, and a roller assembly arranged in the lower end cavity of the push-pull positioning seat; a central through hole is provided on the push-pull positioning seat, and a plurality of first guide holes and second guide holes are provided on the push-pull positioning seat at the periphery of the central through hole along the up and down directions; the grinding wheel assembly includes a grinding wheel seat, a grinding wheel rotatably arranged on the grinding wheel seat, and a roller assembly vertically arranged downward. The first guide rod is provided on the lower end surface of the grinding wheel seat and is slidably connected to the first guide hole, the motor is fixed on the grinding wheel seat and is transmission-connected to the central rotating shaft of the grinding wheel; the roller assembly includes a roller seat, a roller rotatably arranged on the roller seat, and a second guide rod uprightly arranged on the upper end surface of the roller seat and slidably connected to the second guide hole; an adjusting screw is provided between the grinding wheel seat and the roller seat for adjusting the distance between the grinding wheel seat and the roller seat, and the adjusting screw passes through the central through hole on the push-pull positioning seat.

[0018] Preferably, the adjusting screw is composed of an upper screw, a lower screw and an external hexagon connected between the upper screw and the lower screw, and the thread rotation directions of the upper screw and the lower screw are opposite, and a two-way ratchet wrench for operating the rotation of the adjusting screw is provided on the outer sleeve of the external hexagon, the upper screw is threadedly connected to the grinding wheel seat, and the lower screw is threadedly connected to the roller seat; the upper end of the push-pull positioning seat is provided with an infrared rangefinder digital display for detecting the height position of the grinding wheel seat.

[0019] For the convenience of operation, a leaning device is provided on one side of the grinding wheel seat for leaning against the outer side surface of the hollow enclosure during grinding operations. The leaning device includes a first leaning arm fixed to one side of the grinding wheel seat and a first guide wheel provided on the first leaning arm.

[0020] A further improvement is that the profiling device also includes a second profiling arm detachably connected to the other side of the grinding wheel seat and a second guide wheel arranged on the second profiling arm; during the grinding operation, the wall of the hollow profiling panel is located between the first guide wheel and the second guide wheel.

[0021] The detachable arrangement of the second supporting mold arm facilitates the installation of the push-pull type automatic grinding device.

[0022] Preferably, a slide groove is provided on the grinding wheel seat, and the second supporting mold arm is movably arranged on the slide groove and fixed by screws.

[0023] Preferably, a circle of flange plates is provided on the outer side of the middle part of the hollow coaming, and the hatch cover lifting and fixing tooling includes a pair of parallel and spaced channel steels, and support feet are provided at both ends of the channel steels. The support feet are fixed to the deck surface by spot welding, and the flange plates of the hollow coaming are supported on the pair of channel steels and fixed by a pressure plate provided on the upper end surface of the channel steels.

[0024] In order to facilitate the grinding operation and prevent interference, preferably, the length of the channel steel is greater than the outer dimensions of the hollow enclosure.

[0025] Before the trimming operation, the hatch cover is fixed in advance just above the hatch deck of the ship by the hatch cover lifting and fixing tooling, so that an installation space for installing the push-pull automatic grinding device is left between the lower end of the hatch cover coaming and the hatch deck of the ship, and the push-pull automatic grinding device is installed in the above-mentioned installation space.

[0026] During the dressing operation, the motor is turned on and the push-pull automatic grinding device is pushed forward along a circle of the coaming by pushing and pulling the handle. The rotating grinding wheel dresses and grinds the lower end surface of the coaming, so that the vertical distance between each part of the lower end surface of the coaming and the ship's hatch deck surface is trimmed to an equal distance.

[0027] Dressing can be performed gradually as needed, and the grinding allowance can be adjusted at any time by using a two-way ratchet wrench to adjust the grinding wheel height to achieve the grinding feed of the grinding wheel. The grinding feed of the grinding wheel can be controlled by an infrared distance meter.

[0028] The beneficial effects of the present invention are:

[0029] First, the modified structure and construction process of a hatch cover of the present invention provides a balancing cantilever with a balancing block on the cover plate, which can greatly reduce the opening force of the cover plate and facilitate the opening of the cover plate.

[0030] Secondly, the present invention provides a modified structure and construction process for a hatch cover, wherein a hatch cover lifting and fixing tool is provided to suspend and fix the hatch cover directly above the hatch on the ship deck, and then a push-pull type automatic grinding device is used to trim the lower end face of the hatch cover upper coaming. By utilizing the constant spacing between the upper end grinding wheel and the lower end roller of the push-pull type automatic grinding device, even if the deck of the ship hatch is uneven, the lower end face of the coaming and the deck surface can be trimmed to an equal distance, thereby achieving good docking between the coaming and the deck surface, thereby improving the quality of the docking welding between the hatch cover and the ship hatch deck, while also reducing the amount of trimming and improving the production efficiency of the trimming operation.

[0031] Third, the modification structure and construction process of the hatch cover of the present invention adopts a special push-pull automatic grinding device to perform the finishing operation on the lower end surface of the hatch cover upper panel, overcoming the disadvantages of conventional grinding and finishing methods such as low efficiency, the need for repeated lifting and repeated grinding, the troublesome operation, the large workload and the difficulty in ensuring the quality of grinding and finishing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of a hatch cover modification structure and construction process of the present invention;

[0033] Figure 2 yes Figure 1 A top view of the balancing cantilever and balancing weight;

[0034] Figure 3 This is a schematic diagram of using a hatch cover lifting and fixing fixture to lift and fix the hatch cover, and using a push-pull type automatic grinding device to grind the lower end surface of the hollow coaming;

[0035] Figure 4 yes Figure 3 Cross-sectional view (top view) of the hollow coaming in FIG;

[0036] Figure 5 yes Figure 3 A partial enlarged view of the push-pull automatic grinding device.

[0037] In the figure: 1. Hatch cover, 2. Hollow coaming, 3. Cover, 4. Hinge device, 5. Plane coaming, 6. Arc coaming, 7. Balancing arm, 8. Balancing block, 9. First balancing block, 10. Second balancing block, 11. Center linkage opening device, 12. Deck, 13. Hatch cover lifting and fixing fixture, 14. Push-pull automatic grinding device, 15. Push-pull positioning seat, 16. Push-pull handle, 17. Flange plate, 18. Roller, 19. Motor, 20. Grinding wheel, 21. Cavity, 22 , channel steel, 23, pressure plate, 24, center through hole, 25, first guide hole, 26, second guide hole, 27, grinding wheel seat, 28, screw, 29, first guide rod, 30, roller seat, 31, slide groove, 32, second guide rod, 33, adjusting screw, 34, upper screw, 35, lower screw, 36, two-way ratchet wrench, 37, infrared distance measuring digital display, 38, supporting device, 39, first supporting arm, 40, first guide wheel, 41, second supporting arm, 42, second guide wheel. DETAILED DESCRIPTION

[0038] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0039] like Figures 1 to 5 The figure shows an embodiment of the modification structure and construction process of a hatch cover of the present invention, wherein the hatch cover 1 includes a hollow coaming 2, a cover plate 3 arranged at the upper end of the hollow coaming 2, and a hinge device 4 connected between one side of the cover plate 3 and one side of the hollow coaming 2; the hollow coaming 2 includes four planar coamings 5 ​​that are connected together, and a circular arc coaming 6 is transitionally connected between two adjacent planar coamings 5; the modification structure of the hatch cover 1 includes a pair of balancing cantilevers 7 connected to the cover plate 3, one end of the balancing cantilever 7 is connected to the side of the cover plate 3 close to the hinge device 4, and the other end of the balancing cantilever 7 extends toward a side away from the center position of the cover plate 3, and a balancing block 8 is connected between the cantilever ends of the pair of balancing cantilevers 7.

[0040] Preferably, the balancing mass 8 includes a first balancing mass 9 connected between the cantilever ends of the pair of balancing cantilevers 7 and a second balancing mass 10 connected to the first balancing mass 9 .

[0041] In this embodiment, the hatch cover 1 further includes a central linkage opening device 11 provided at the center of the cover plate 3 .

[0042] A construction process for a modified structure of a hatch cover comprises the following steps:

[0043] (1) Fabrication of balancing cantilever and balancing weight: Fabricate a pair of balancing cantilever 7 and balancing weight 8;

[0044] (2) Remodeling of the hatch cover: Weld a pair of balancing arms 7 to the cover plate, and weld a balancing block 8 between the cantilever ends of the pair of balancing arms 7;

[0045] (3) Trial assembly and repair of hatch covers: hoist the whole assembly of the hatch cover 1 onto the deck 12 where the hatch is opened, check the contact between the lower end surface of the hollow coaming 2 and the deck 12. If poor contact is found, lift and fix the hollow coaming 2 and grind its lower end surface to ensure that the lower end surface of the hollow coaming 2 and the deck surface can fully contact after assembly;

[0046] (4) Formal assembly and welding of the hatch cover: After the lower end surface of the hollow coaming 2 is ground into place, the hollow coaming 2 is repositioned on the deck 12 with the hatch, and the lower end of the hollow coaming 2 and the deck 12 are welded.

[0047] In the process of trial installation and repair of the hatch cover in step (3), the hatch cover lifting and fixing tool 13 is used to lift the hatch cover 1 as a whole and then fix it, and then the push-pull type automatic grinding device 14 is used to grind the lower end surface of the hollow coaming 2;

[0048] The push-pull automatic grinding device 14 includes a push-pull positioning seat 15 that is horizontally movable on the surface of the deck 12, a push-pull handle 16 connected to the push-pull positioning seat 15, and a grinding component that is vertically movable on the push-pull positioning seat 15. The lower end of the grinding component is provided with a roller 18 that contacts the surface of the deck 12 below the hollow coaming 2, and the upper end of the grinding component is provided with a grinding wheel 20 driven by a motor 19 for grinding the lower end surface of the hollow coaming 2.

[0049] Preferably, the motor 19 is an electric motor or a pneumatic motor.

[0050] As a preferred solution of the push-pull type automatic grinding device in this embodiment, a cavity 21 is opened upward at the lower end of the push-pull positioning seat 15, and the grinding component includes a grinding wheel assembly arranged on the upper part of the push-pull positioning seat 15, and a roller assembly arranged in the lower end cavity 21 of the push-pull positioning seat 15. A central through hole 24 is provided on the push-pull positioning seat 15, and a number of first guide holes 25 and second guide holes 26 are provided on the push-pull positioning seat 15 along the upper and lower directions on the periphery of the central through hole 24; the grinding wheel assembly includes a grinding wheel seat 27, a grinding wheel 20 rotatably arranged on the grinding wheel seat 27, and a roller assembly arranged downward on the grinding wheel seat 27. The first guide rod 29 is connected to the lower end surface and is slidably matched with the first guide hole 25. The motor 19 is fixed on the grinding wheel seat 27 and is transmission-connected to the central rotating shaft of the grinding wheel 20. The roller assembly includes a roller seat 30, a roller 18 rotatably arranged on the roller seat 30, and a second guide rod 32 uprightly arranged on the upper end surface of the roller seat 30 and slidably matched with the second guide hole 26. An adjusting screw 33 is provided between the grinding wheel seat 27 and the roller seat 30 for adjusting the distance between the grinding wheel seat 27 and the roller seat 30. The adjusting screw 33 passes through the central through hole 24 on the push-pull positioning seat 15.

[0051] Preferably, the adjusting screw 33 is composed of an upper screw 34, a lower screw 35 and an outer hexagon connected between the upper screw 34 and the lower screw 35, and the thread rotation direction of the upper screw 34 and the lower screw 35 are opposite, and a two-way ratchet wrench 36 for operating the rotation of the adjusting screw 33 is provided on the outer hexagon, the upper screw 34 is threadedly connected to the grinding wheel seat 27, and the lower screw 35 is threadedly connected to the roller seat 30; the upper end of the push-pull positioning seat 15 is provided with an infrared rangefinder digital display 37 for detecting the height position of the grinding wheel seat 27.

[0052] For the convenience of operation, a profiling device 38 is provided on one side of the grinding wheel seat 27 for leaning against the outer side surface of the hollow enclosure 2 during grinding operations. The profiling device 38 includes a first profiling arm 39 fixed to one side of the grinding wheel seat 27 and a first guide wheel 40 provided on the first profiling arm 39.

[0053] A further improvement scheme is: the profiling device 38 also includes a second profiling arm 41 detachably connected to the other side of the grinding wheel seat 27, and a second guide wheel 42 arranged on the second profiling arm 41; during the grinding operation, the panel wall of the hollow panel 2 is located between the first guide wheel 40 and the second guide wheel 42.

[0054] The detachable arrangement of the second supporting mold arm 41 facilitates the installation of the push-pull type automatic grinding device 14 .

[0055] Preferably, a sliding groove 31 is provided on the grinding wheel seat 27 , and the second backing arm 41 is movably provided on the sliding groove 31 and fixed by a screw 28 .

[0056] Preferably, a circle of flange plate 17 is provided on the outer side of the middle part of the hollow coaming 2, and the hatch cover lifting and fixing tooling 13 includes a pair of parallel and spaced channel steels 22, and support feet (not shown in the figure) are provided at both ends of the channel steel 22. The support feet are fixed to the surface of the deck 12 by spot welding, and the flange plate 17 of the hollow coaming 2 is supported on the pair of channel steels 22 and fixed by a pressure plate 23 provided on the upper end surface of the channel steel 22.

[0057] In order to facilitate the grinding operation and prevent interference, preferably, the length of the channel steel 22 is greater than the outer size of the hollow enclosure 2.

[0058] Before the trimming operation, the hatch cover 1 is fixed in advance just above the hatch deck 12 of the ship by the hatch cover lifting and fixing tool 13, so that an installation space for installing the push-pull automatic grinding device 14 is left between the lower end of the hatch cover 1's coaming 2 and the ship's hatch deck 12, and the push-pull automatic grinding device 14 is installed in the above-mentioned installation space.

[0059] During the dressing operation, the motor 19 is turned on, and the push-pull automatic grinding device 14 is pushed forward along a circle of the coaming 2 by pushing and pulling the handle 16. The rotating grinding wheel 20 dresses and grinds the lower end surface of the coaming 2, so that the vertical distance between each part of the lower end surface of the coaming 2 and the surface of the ship's hatch deck 12 is trimmed to an equal distance.

[0060] As needed, the dressing operation can be carried out step by step, and the grinding allowance can be adjusted at any time by the two-way ratchet wrench 36 to adjust the grinding wheel 20 height to achieve the grinding feed of the grinding wheel 20. Wherein, the grinding feed of the grinding wheel 20 can be controlled by the infrared rangefinder 37.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A construction process for a modified structure of a hatch cover, characterized in that: The hatch cover comprises a hollow coaming, a cover plate arranged at the end portion of the hollow coaming, and a hinge device connected between one side of the cover plate and one side of the hollow coaming; the hollow coaming comprises four plane coamings connected to each other, and a circular arc coaming is transitionally connected between two adjacent plane coamings; the modified structure of the hatch cover comprises a pair of balancing cantilevers connected to the cover, one end of the balancing cantilever is connected to a side of the cover close to the hinge device, and the other end of the balancing cantilever extends toward a side away from the center position of the cover, and a balancing block is connected between the cantilever ends of the pair of balancing cantilevers; the construction process of the modified structure of the hatch cover comprises the following steps: (1) Preparation of balancing cantilever and balancing mass: Prepare a pair of balancing cantilever and balancing mass; (2) Remodeling of hatch covers: Weld a pair of balancing arms to the cover plate, and weld balancing blocks between the ends of the balancing arms; (3) Trial assembly and repair of hatch covers: hoist the whole assembly of the hatch cover to the deck surface with the hatch opening, check the contact between the lower end surface of the hollow coaming and the deck surface, if poor contact is found, lift and fix the hollow coaming and grind its lower end surface to ensure that the lower end surface of the hollow coaming can fully contact with the deck surface after assembly; (4) Formal assembly welding of hatch covers: After the lower end surface of the hollow coaming is ground into place, the hollow coaming is repositioned on the deck surface with the hatch, and the lower end of the hollow coaming is welded to the deck surface; During the test assembly and repair of the hatch cover in step (3), the hatch cover is lifted and fixed as a whole using a hatch cover lifting and fixing tool, and then the lower end surface of the hollow coaming is ground using a push-pull type automatic grinding device; Among them, the push-pull type automatic grinding device includes a push-pull positioning seat horizontally arranged on the deck surface, a push-pull handle connected to the push-pull positioning seat, and a grinding component arranged on the push-pull positioning seat for up and down movement, the lower end of the grinding component is provided with a roller in contact with the deck surface below the hollow enclosure, and the upper end of the grinding component is provided with a grinding wheel driven by a motor for grinding the lower end surface of the hollow enclosure.

2. The construction process of the modified structure of a hatch cover according to claim 1, characterized in that: The balancing weight includes a first balancing weight connected between the cantilever ends of the pair of balancing cantilevers and a second balancing weight connected to the first balancing weight.

3. The construction process of the modified structure of a hatch cover according to claim 1, characterized in that: The hatch cover also includes a central linkage opening device arranged at the center position of the cover plate.

4. The construction process of the modified structure of a hatch cover according to claim 1, characterized in that: The lower end of the push-pull positioning seat is upwardly provided with a cavity, and the grinding component comprises a grinding wheel assembly arranged on the upper part of the push-pull positioning seat, and a roller assembly arranged in the lower end cavity of the push-pull positioning seat, and a central through hole is arranged on the push-pull positioning seat, and a plurality of first guide holes and second guide holes are arranged on the push-pull positioning seat at the periphery of the central through hole along the up and down directions; the grinding wheel assembly comprises a grinding wheel seat, a grinding wheel rotatably arranged on the grinding wheel seat, and a first guide rod vertically arranged downward on the lower end surface of the grinding wheel seat and slidably connected with the first guide hole, and the motor is fixed on the grinding wheel seat and is mutually transmission-connected with the central rotating shaft of the grinding wheel; the roller assembly comprises a roller seat, a roller rotatably arranged on the roller seat, and a second guide rod vertically arranged upward on the upper end surface of the roller seat and slidably connected with the second guide hole; an adjusting screw for adjusting the distance between the grinding wheel seat and the roller seat is arranged between the grinding wheel seat and the roller seat, and the adjusting screw passes through the central through hole on the push-pull positioning seat.

5. The construction process of the modified structure of the hatch cover according to claim 4, characterized in that: The adjusting screw is composed of an upper screw, a lower screw and an outer hexagonal body connected between the upper screw and the lower screw, and the thread rotation directions of the upper screw and the lower screw are opposite. A two-way ratchet wrench for operating the rotation of the adjusting screw is arranged on the outer sleeve of the outer hexagonal body. The upper screw is threadedly connected to the grinding wheel seat, and the lower screw is threadedly connected to the roller seat. The upper end of the push-pull positioning seat is provided with an infrared distance measuring digital display for detecting the height position of the grinding wheel seat.

6. The construction process of the modified structure of the hatch cover according to claim 5, characterized in that: A profiling device for leaning against the outer side of the hollow enclosure during grinding is arranged on one side of the grinding wheel seat, and the profiling device includes a first profiling arm fixed to one side of the grinding wheel seat and a first guide wheel arranged on the first profiling arm.

7. The construction process of the modified structure of the hatch cover according to claim 6, characterized in that: The profiling device also includes a second profiling arm detachably connected to the other side of the grinding wheel seat and a second guide wheel arranged on the second profiling arm; during the grinding operation, the enclosure wall of the hollow enclosure is located between the first guide wheel and the second guide wheel.

8. The construction process of the modified structure of the hatch cover according to claim 7, characterized in that: The grinding wheel seat is provided with a slide groove, and the second mold arm is movably arranged on the slide groove and fixed by screws.

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