CN216553044U

CN216553044U - Middle keel structure

Info

Publication number: CN216553044U
Application number: CN202122081921.3U
Authority: CN
Inventors: 曹海平
Original assignee: Liuzhou Zhijia Metal Technology Co ltd
Current assignee: Liuzhou Zhijia Metal Technology Co ltd
Priority date: 2021-08-31
Filing date: 2021-08-31
Publication date: 2022-05-17
Anticipated expiration: 2031-08-31

Abstract

The utility model discloses a middle keel structure, which comprises a keel main body, a keel frame and a keel frame, wherein the keel main body is in a strip shape and is provided with an accommodating space; the first structure body is arranged at one end of the keel main body, and the lower end of the first structure body extends to form a connecting part; the utility model can be formed by connecting the middle keel and the structural bodies at the two ends in a split welding or integrated die-casting mode, can be used for supporting floor surfaces, can also be matched with the early-dismantling heads at the two ends for fastening connection, is convenient to dismantle and take, strengthens the supporting structure, has quick structure forming and high strength, avoids the defects of easy generation of various defects at welding seams during welding, such as slag inclusion, holes, incomplete welding, larger welding thermal stress generation and the like, and has long service life.

Description

Middle keel structure

Technical Field

The utility model relates to the technical field of building support, in particular to a middle keel structure.

Background

At present, China is in a stage of rapid development of urbanization, urban housing construction is heavy, high-rise buildings all use reinforced concrete as a main body, and building templates are indispensable construction materials and important machines. The building template technology relates to the consumption of resources and energy sources, influences the environmental protection and has direct effect on the engineering quality, the construction cost and the benefit;

at present, the labor cost of the building industry in China is greatly increased, the personnel is in short supply, the problems of quality, progress, safety and material waste commonly occur in the traditional construction technology, and a plurality of enterprises are searching for new construction technology and new materials, wherein the most remarkable technology is an aluminum template, an aluminum frame plywood template and an early-dismantling template supporting technology derived from the aluminum template, which is generally called as an aluminum template technology;

in the building industry, the main body and the supporting ends at two ends of the traditional aluminum alloy middle keel are generally formed by cutting aluminum profiles and then are connected and formed by an electric fusion welding method. The method of electric fusion welding has the advantages of low process efficiency, high energy consumption, and great pollution of photoelectricity and flue gas generated in the process of electric fusion welding to the environment, and is not beneficial to environmental protection. In addition, by adopting the electric fusion welding process, various defects such as slag inclusion, holes, incomplete penetration, large welding thermal stress and the like are easily generated at the welding seam of the template; therefore, the service life of the traditional aluminum alloy keel template is generally very short, and the use times are also few.

SUMMERY OF THE UTILITY MODEL

This section is for the purpose of summarizing some aspects of embodiments of the utility model and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the abstract of the specification and the title of the application to avoid obscuring the purpose of this section, the abstract of the specification and the title of the application, and such simplifications or omissions are not intended to limit the scope of the utility model.

The present invention has been made keeping in mind the above problems occurring in the prior art.

Therefore, the technical problem to be solved by the utility model is that the traditional electric melting welding keel connecting structure is not beneficial to environmental protection, has poor strength and short service life.

In order to solve the technical problems, the utility model provides the following technical scheme: a middle keel structure comprises a keel main body which is arranged in a strip shape and forms an accommodating space; and the first structure body is arranged at one end of the keel main body, and the lower end of the first structure body extends to form a connecting part.

As a preferable aspect of the intermediate keel structure of the utility model, wherein: the keel comprises a keel body and is characterized in that two side faces of the keel body are provided with first weight reducing grooves which are sunken inwards, and a plurality of through openings are arranged in the first weight reducing grooves.

As a preferable aspect of the intermediate keel structure of the utility model, wherein: the first structure body is symmetrically arranged at two ends of the keel main body.

As a preferable aspect of the intermediate keel structure of the utility model, wherein: the keel structure is characterized in that lining plates are arranged at the bottoms of two sides of the keel main body, supporting platforms are arranged on two sides of the connecting portion S of the first structure body, and limiting plates are arranged at the tops of the supporting platforms.

As a preferable aspect of the intermediate keel structure of the utility model, wherein: the lining plate is pressed on the supporting platform, the limiting plate extends into the accommodating space, and the limiting plate is attached to the side wall of the accommodating space.

As a preferable aspect of the intermediate keel structure of the utility model, wherein: an accommodating cavity is formed in the first structure body, and second lightening grooves are formed in two sides of the first structure body.

As a preferable aspect of the intermediate keel structure of the utility model, wherein: the bottom of the two sides of the connecting part S of the first structure body is provided with a platform, and an installation space is reserved between the platform and the supporting platform. The both ends of the keel main body are provided with inclined end faces.

As a preferable aspect of the intermediate keel structure of the utility model, wherein: the keel main body is connected with the first structure body in a split or integrated manner.

As a preferable aspect of the intermediate keel structure of the utility model, wherein: the rib plate is vertically connected with two side walls of the accommodating space, and one end of the rib plate is vertically connected with the top wall of the accommodating space.

As a preferable aspect of the intermediate keel structure of the utility model, wherein: and a round hole is formed in the second weight-reducing groove.

The utility model has the beneficial effects that: the utility model can use friction stirring to weld two extruded and die-cast structural bodies made of different materials into an integrated middle keel, can be used for supporting a floor surface, can also be matched with early-dismantling heads at two ends for fastening connection, is convenient to dismantle and take, strengthens a supporting structure, has quick structural formation and high strength, avoids the defects of easy generation of various defects at a welding seam during welding, such as slag inclusion, holes, incomplete welding, generation of larger welding thermal stress and the like, and has long service life.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:

figure 1 is a view of the first embodiment of the keel body and first structure connection.

Figure 2 is a detailed view of the keel body and first structure of the second embodiment.

Fig. 3 is a structural view of the third and fifth embodiments of the keel body and the first structural body which are integrated.

Figure 4 is a structure diagram of the split connection of the keel main body and the first structure body in the third, fourth and seventh embodiments.

Fig. 5 is a structure diagram of rib plates and ribs in the sixth and seventh embodiments.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, the references herein to "one embodiment" or "an embodiment" refer to a particular feature, structure, or characteristic that may be included in at least one implementation of the present invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Example 1

Referring to fig. 1, there is provided a first embodiment of the present invention, which provides a middle keel structure, comprising a keel body 100 and a first structure 200, wherein the keel body 100 is disposed on a floor surface of a whole building for supporting the floor surface, and the first structure 200 is disposed at one end of the keel body 100 for being coupled with an early-dismantling head.

Keel main part 100 is rectangular form setting to from the sunken accommodation space N that is formed with in bottom, the intercommunication is run through at accommodation space N both ends, can alleviate keel main part 100 'S weight, is convenient for install at the floor top, first structure 200, set up in keel main part 100' S one end, its lower extreme extend and form connecting portion S, keel main part 100 in the middle of as, first structure 200 can also the symmetry set up at keel main part 100 'S both ends, first structure 200 is located keel main part 100' S both ends and connecting portion S all can connect early the head of tearing open.

The keel body 100 may be formed by extrusion, the first structure 200 may be formed by die casting, and the keel body 100 and the first structure 200 may be joined together by friction stir welding or friction stir spot welding.

Specifically, the keel main body 100 and the first structural body 200 are connected in a split or integrated manner, and when the keel main body 100 and the first structural body 200 are connected in the split manner, the keel main body 100 and a connecting part S at the lower end of the first structural body 200 are welded together in a friction stir welding or friction stir spot welding manner; when the integral connection is carried out, liquid or semisolid alloy is filled into a cavity of a die-casting die at a higher speed by adopting a die-casting pouring mode, and the alloy is solidified and molded under high pressure.

Example 2

Referring to fig. 2, a second embodiment of the present invention, which is based on the previous embodiment, can reduce the weight and material of the keel body 100 and the first structural body 200, further reducing the cost.

Specifically, the first weight reducing grooves 101 which are recessed inwards are formed in two side faces of the keel main body 100, the through holes 102 are arranged in the first weight reducing grooves 101, and the first weight reducing grooves 101 and the accommodating space N are formed to reduce unnecessary weight on the keel main body 100 and reduce material and control cost.

The through holes 102 are arranged in the first weight reduction grooves 101 in a transverse array mode, so that the weight is reduced, meanwhile, other components can be connected to the floor surface conveniently, reinforcing steel bars or cross beams in the building can penetrate through the through holes after the through holes are installed on the top surface of the floor, the structure of the whole building is reinforced, and the effect of reinforcing and supporting is achieved.

The first structure body 200 is provided with a containing cavity M, the two sides of the connecting part S at the lower end of the first structure body 200 are provided with second weight-reducing grooves 204, the second weight-reducing grooves 204 are provided with round holes 204a, and the containing cavity M and the second weight-reducing grooves 204 reduce unnecessary solid structures and materials in the first structure body 200 on one hand, reduce the weight at the two sides of the first structure body 200 on the other hand, and avoid unstable fixation caused by overweight of the first structure body 200 while playing a supporting role.

Example 3

Referring to fig. 3 and 4, in a third embodiment of the present invention, based on the previous embodiment, the keel body 100 and the first structural body 200 may be connected in a separated manner or may be integrally formed by die casting, and during the integral die casting, a liquid or semi-solid alloy is filled into a cavity of a die casting mold at a high speed, and the alloy is solidified and formed under high pressure, so that advantages such as high productivity and high dimensional accuracy of a product are provided, a complicated structure can be formed, and the product has high structural rigidity and low production cost.

The outside extension in fossil fragments main part 100 both sides bottom sets up welt 104, and the connecting portion S both sides of first structure 200 set up saddle 202, saddle 202 top sets up limiting plate 203, and limiting plate 203 forms and matches with the angle that welt 104 in the fossil fragments main part 100 formed with saddle 202 certain angle. Specifically, the lining board 104 is pressed on the supporting platform 202, the limiting board 203 extends into the accommodating space N from the bottom of the accommodating space N, and the limiting board 203 is attached to the sidewall of the accommodating space N, so that the whole keel main body 100 is pressed on the first structure 200.

Further, the lining plate 104 and the pallet 202 may be formed by separate welding, and the spacing plate 203 and the sidewall of the accommodating space N may also be formed by separate welding. Specifically, the lining plate 104 and the pallet 202 are welded together by friction stir welding or friction stir spot welding, the position of the friction stir welding is located on the lining plate 104, the method comprises the steps of enabling a lining plate 104 and a supporting platform 202 to generate heat for melting in a mode that a stirring head rotating at a high speed is inserted into a workpiece, rotating for welding and advancing at the same time, enabling metal around the stirring head to form a plastic softening layer, filling a cavity formed behind the stirring head with the softening layer metal under the rotating action of the stirring head, enabling the friction stir spot welding positions to be located at the end parts of two sides of a keel main body 100, enabling the stirring head to penetrate into an accommodating space N from the two sides of the keel main body 100, meanwhile, friction heat is generated by penetrating through the contact part of the stirring head of the limiting plate 203, so that the limiting plate 203 and the metal on the two sides of the keel main body 100 form a plastic softening layer, and the softening layer metal is fully mixed together under the action of rotation of the stirring head to realize solid-state welding of the materials.

Further, the lining plate 104 and the pallet 202 may be integrally welded, and the limiting plate 203 and the sidewall of the accommodating space N may also be integrally welded. Specifically, the die is cast in a die casting manner.

Example 4

Referring to fig. 4, a fourth embodiment of the present invention is shown, which is based on the previous embodiment, the keel body 100 has two ends extending from the middle of the whole support system, and the two ends are respectively connected to the early-dismantling head, so that the two ends are provided with special structures for matching with the early-dismantling head.

Specifically, the keel body 100 is provided with inclined end surfaces 103 at both ends thereof, and similarly, the early-dismantling head is also provided with inclined end surfaces at both ends thereof, so that the keel body 100 is conveniently connected with the early-dismantling head at both ends thereof.

Furthermore, the inclination angles of the end surfaces 103 at the two ends of the keel main body 100 are consistent with those of the two ends of the early-dismantling head, and the end surfaces 103 are tightly attached to the early-dismantling head and then can be fixedly connected together through BB strips.

Example 5

Referring to fig. 3, a fifth embodiment of the present invention is provided, which is based on the previous embodiment, and can facilitate the connection of the first structure 200 at both ends of the keel body 100 to the early-removed keel or the end keel on the floor surface.

The bottom of the two sides of the connecting portion S of the first structure 200 is provided with a platform 205, an installation space L is left between the platform 205 and the supporting platform 202, and the installation space L can be matched with the structure of the early-dismantling head for placing and connecting BB strips. Specifically, the first structure body 200 is formed with an accommodating cavity M, the two sides of the first structure body 200 are provided with second lightening grooves 204, the second lightening grooves 204 are provided with round holes 204a, the round holes 204a on the two sides of the first structure body 200 correspond to each other, the installation space L and the early-dismantling head structure are in the same horizontal space, BB bars can be transversely placed in the installation space L and extend to the early-dismantling head or end keel, and then pass through the round holes 204a through bolts to be fixedly connected with nuts, and the BB bars can fixedly connect the first structure body 200 and other components together.

Example 6

Referring to fig. 5, a sixth embodiment of the present invention is provided, which is based on the previous embodiment, and the rib N-1 and the rib plate N-2 of the reinforcing structure are provided to play a role of reinforcing and supporting the inside of the accommodating space N of the keel body 100.

The rib N-1 and the rib plate N-2 are arranged in the accommodating space N, the rib N-1 is installed on the top wall of the accommodating space N in a cross mode, the rib N-1 extends along the length of the accommodating space N, and the rib plate N-2 is vertically connected with two side walls of the accommodating space N, and one end of the rib plate N-2 is vertically connected with the top wall of the accommodating space N and used for supporting the structure of the reinforced keel main body 100.

Further, a rib plate N-2 may be provided between the keel body 100 and the first structure 200 to reinforce the connection between the keel body 100 and the first structure 200.

Example 7

Referring to fig. 4 and 5, a seventh embodiment of the utility model, which is based on the above embodiment, provides a method for manufacturing a center keel structure.

In traditional building technical field, fossil fragments main part 100 and first structure 200 adopt ordinary 6061 aluminum alloy material, then with the mode that adopts the electric welding between fossil fragments main part 100 and the first structure 200 with both fixed together, adopt the method of electric fusion welding, its process efficiency is very low, the energy consumption is big, the photoelectricity and the flue gas that the electric fusion welding process produced are great to environmental pollution, are unfavorable for green. In addition, by adopting the electric fusion welding process, various defects such as slag inclusion, holes, incomplete penetration, large welding thermal stress and the like are easily generated at the welding seam of the template; therefore, the service life of the traditional aluminum alloy keel template is generally very short, and the use times are also few.

The embodiment provides a processing method including: the keel main body 100, the first structure body 200, the ribs N-1 and the rib plates N-2 are integrally formed, specifically, liquid or semi-solid metal is poured in a mould and integrally formed by pressure casting, and the liquid or semi-solid metal has the advantages of high production rate, high product size precision and the like.

In this embodiment, the pallet 202 and the backing plate 104 are formed in a wider and thicker configuration, and the width and thickness are greater than those of the pallet 202 and the backing plate 104 cut from aluminum profiles, and the bending can be performed ninety degrees — thereby affecting the manner in which the "weld" is subsequently selected. The connection between the pallet 202 and the lining plate 104 is made by friction stir welding, the lining plate 104 and the pallet 202 are melted by heat generated by inserting a high-speed rotating stirring head into the workpiece (i.e. the end part on the lining plate 104) and rotating and welding while advancing, and then the surrounding metal is made to form a plastic softening layer which fills the cavity formed behind the stirring head under the action of the rotation of the stirring head.

Furthermore, the rib N-1 and the rib plate N-2 are arranged in the accommodating space N and integrally formed with the keel main body 100, so that the problem that welding cannot be performed due to space limitation in the traditional electric welding process is solved.

In this embodiment, the die casting allows the lining plate 104 of the keel body 100, the tray 202 of the first structure 200, and the position limiting plate 203 of the tray 202 to have a thickness greater than the sheet thickness of the aluminum profile structure.

The first structure 200 at tradition fossil fragments main part 100 and both ends generally all adopts the aluminium alloy cutting to form, fossil fragments main part 100 is thinner with the structure 200 size at both ends, can't adopt friction stir welding or friction stir spot welding's mode to be connected, can only adopt the technology of electric fusion welding to go on, this joint strength who just leads to whole end fossil fragments is not enough, take place to damage easily in long-time use, at this moment because the space restriction of structure itself, it further welds to be difficult to adopt electric capacity welding, just need demolish the change to whole fossil fragments, the cost is very high.

If the traditional keel is connected in a friction stir welding or friction stir spot welding mode, due to the limitation of the size of the material, a boss is usually additionally welded in the hollow inner cavity of the keel for connection, so that the processing and transportation cost is greatly increased.

Due to the operational characteristics of friction stir welding and friction stir spot welding: friction stir welding is a method of utilizing a stirring head rotating at a high speed to prick into a workpiece and then move along a welding direction, generating friction heat at a contact part of the stirring head and the workpiece to enable surrounding metal to form a plastic softening layer, filling a cavity formed behind the stirring head with the softening layer metal under the rotation action of the stirring head, and realizing solid state welding of materials under the extrusion action of a shaft shoulder of the stirring head; the main difference between the friction stir spot welding and the conventional friction stir welding is that a stirring head of the friction stir spot welding does not need to move left and right after being pricked into a workpiece, the contact part of the workpiece to be connected and the stirring head generates friction heat to enable surrounding metal to form a plastic softening layer, and the softening layer metal is fully mixed together under the rotation action of the stirring head to realize the solid-state welding of the material.

Therefore, friction stir welding and friction stir spot welding require that the backing plate 104, the pallet 202, and the limit plate 203 have sufficient thicknesses; the lining plate 104 is installed on the saddle 202, the lining plate 104 and the saddle 202 are fixedly connected through friction stir welding, the limiting plate 203 extends into the accommodating space N and clings to two inner side walls of the keel main body 100, and the lining plate is fixedly connected in a friction stir spot welding mode.

In this embodiment, the keel main body 100 is formed by extrusion, the first structural body 200 is formed by die casting, a complex structure can be formed, the two sides of the first structural body 200 form the support platforms 202 bent by ninety degrees, the two sides of the keel main body 100 form the lining plates 104 bent by ninety degrees, convenience and stability during welding are improved, the formed lining plates 104 and the support platforms 202 are both of practice structures, strength of a finished product is further enhanced by friction stir welding, the support platforms 202 are formed with integrated limiting plates 203 during die casting, the limiting plates 203 are attached to the inner wall of the keel main body 100, and the two are stably combined into a whole by friction stir spot welding; between fossil fragments main part 100 and first structure 200, carry out welding moulding in different positions department, consolidated off-the-shelf structure, further strengthened off-the-shelf rigidity, can increase of service life.

The first structural body 200 is formed by die-casting liquid or semisolid alloy, has certain strength, can improve the specification and size of the lining plate 104 and the supporting platform 202 in the connection process, can adapt to a friction stir welding or friction stir spot welding mode, and only needs to dismantle the damaged part when a part of the structural body is damaged, and then uses the friction stir welding mode for installation without replacing the whole end keel, thereby greatly reducing the cost. And on the premise of not influencing the integral bearing effect of the keel, the quality of the whole structure body is reduced as much as possible.

The friction stir welding or friction stir spot welding method adopted in the present embodiment has the following advantages compared to the capacitive welding method:

1) the energy consumption of friction stir welding and friction stir spot welding is extremely low, and is only about 10 percent of that of the traditional electric fusion welding;

2) the friction stir welding and the friction stir spot welding can not generate photoelectricity and smoke, and are beneficial to environmental protection;

3) friction stir welding and friction stir spot welding are solid-state welding, and the welding temperature is much lower than that of electric welding, so that the welding thermal stress is small, and workpieces are not easy to deform; meanwhile, the friction stir welding is not easy to generate the conventional welding defects; the weld properties may approach or even exceed the parent material properties.

It is important to note that the construction and arrangement of the present application as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in this application. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of this invention. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present inventions. Therefore, the present invention is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of the appended claims.

Moreover, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not be described (i.e., those unrelated to the presently contemplated best mode of carrying out the utility model, or those unrelated to enabling the utility model).

It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.

Claims

1. A middle keel structure is characterized in that: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

the keel body (100) is arranged in a strip shape and forms an accommodating space (N); and the number of the first and second groups,

and a first structure body (200) which is arranged at one end of the keel main body (100) and the lower end of which extends to form a connecting part (S).

2. The intermediate keel structure of claim 1, wherein: the keel is characterized in that two side faces of the keel main body (100) are provided with first weight reducing grooves (101) which are sunken inwards, and a plurality of through holes (102) are arranged in the first weight reducing grooves (101).

3. The intermediate keel structure of claim 1 or 2, wherein: the first structure body (200) is symmetrically arranged at two ends of the keel main body (100).

4. The intermediate keel structure of claim 2, wherein: fossil fragments main part (100) both sides bottom sets up welt (104), connecting portion (S) both sides of first structure body (200) set up saddle (202), saddle (202) top sets up limiting plate (203).

5. The intermediate keel structure of claim 4, wherein: the lining plate (104) is pressed on the supporting platform (202), the limiting plate (203) extends into the accommodating space (N), and the limiting plate (203) is attached to the side wall of the accommodating space (N).

6. The intermediate keel structure of claim 1 or 5, wherein: an accommodating cavity (M) is formed in the first structure body (200), and second lightening grooves (204) are formed in two sides of the first structure body (200).

7. The intermediate keel structure of claim 4, wherein: the keel structure is characterized in that platforms (205) are arranged at the bottoms of two sides of a connecting portion (S) of the first structure body (200), an installation space (L) is reserved between each platform (205) and the corresponding support platform (202), and inclined end faces (103) are arranged at two ends of the keel main body (100).

8. The intermediate keel structure of claim 6, wherein: the keel main body (100) is connected with the first structure body (200) in a split or integrated manner.

9. The intermediate keel structure of claim 8, wherein: the rib plates (N-2) are vertically connected with two side walls of the accommodating space (N) and one end of each rib plate (N-2) is vertically connected with the top wall of the accommodating space (N).

10. The intermediate keel structure of claim 6, wherein: and a round hole (204a) is formed in the second lightening groove (204).