TWI781025B - Heavy raised floor - Google Patents

Abstract

A raised floor includes a top plate and a rib structure, wherein the rib structure has a plurality of main ribs with a height of at least 25 mm formed on the top plate to enhance the structural strength of the raised floor. Therefore, when the raised floor carries the heavier equipment in the semiconductor manufacturing process, the problem of the raised floor cracking can be avoided.

Description

Heavy duty raised floor

The invention relates to a floor, especially a heavy raised floor with a rib structure.

At present, in semiconductor factories, elevated floors with multiple micro-perforations are installed to clean the air quality of the environment and ensure the clean room specifications.

At present, the raised floor system is made by mold casting. In the molding process, the required product is often made by a mold, and before the molding operation, a release layer will be coated on the mold to facilitate the subsequent demoulding operation.

However, it is known that the structural strength of the raised floor is often insufficient, so when the raised floor carries heavier equipment in the semiconductor manufacturing process, the raised floor is prone to breakage. On the other hand, there is also the problem that the raised floor is too heavy, which not only wastes materials, but also increases the manufacturing cost.

Therefore, how to overcome the problems of the above-mentioned conventional technologies has become a difficult problem to be overcome urgently in the industry.

In view of the deficiencies of the above-mentioned prior art, the present invention provides a heavy-duty raised floor comprising: a top plate having opposite ground sides and honeycomb sides; and a rib structure arranged on the honeycomb side of the top plate to form a plurality of The concave part, wherein, the rib structure is sequentially defined from the edge of the top plate to the middle with the first rib, the second rib, the third rib, the fourth rib, the fifth rib, the sixth rib and the seventh rib, and the The first to seventh ribs serve as main ribs, and their height relative to the sides of the honeycomb is at least 25 mm.

In the aforementioned heavy-duty raised floor, the plurality of recesses are arranged in an array to form a honeycomb structure on the side of the honeycomb.

In the aforementioned heavy-duty raised floor, the first rib is formed on the edge of the top plate to become the side rib of the heavy-duty raised floor, which serves as a frame of the heavy-duty raised floor for fixing the feet.

In the aforementioned heavy-duty raised floor, the sum of the heights of the first rib and the top plate is 51 to 62 millimeters, and the thickness of the top plate is 2.7 to 4.8 millimeters.

In the aforementioned heavy-duty raised floor, the width of the first rib is 8.3 to 9.8 mm.

In the aforementioned heavy-duty raised floor, the heights of the second to seventh ribs relative to the honeycomb side are 25 to 56.5 mm.

In the aforementioned heavy-duty raised floor, the widths of the second to seventh ribs are 3.0 to 9.4 mm.

In the aforementioned heavy-duty raised floor, the rib structure further includes a plurality of auxiliary ribs with a height of less than 25 mm, and the plurality of auxiliary ribs are correspondingly formed in each of the recesses, so that the plurality of auxiliary ribs are arranged in a single recess. For example, the plurality of auxiliary ribs extend along a single direction without interlacing each other. Alternatively, the height of the auxiliary rib relative to the side of the honeycomb is at least 6 mm, and its width is at least 2.5 mm.

In the aforementioned heavy-duty raised floor, a plurality of perforations connecting the ground side and the honeycomb side are formed on the top plate, and the positions of the plurality of perforations are corresponding to the plurality of recesses, and a single direction is provided between three adjacent perforations. of the auxiliary rib.

In the aforementioned heavy-duty raised floor, the rib structure forms a well-shaped rib with two seventh ribs in the longitudinal and transverse directions, so as to divide the heavy-duty raised floor into four areas, and the adjacent seventh ribs in the four areas There are 25 sub-regions formed between the second rib, the third rib, the fourth rib, the fifth rib and the sixth rib, and each sub-region has a recess, and the first to sixth ribs are formed by the well-shaped ribs. It is distributed symmetrically on the basis of another concave part formed in the central part of the well-shaped rib formed by the seventh rib. The thickness of the concave part is thicker than the thickness of the top plate, and a cross-shaped rib is arranged in it. , and form a wing plate around the top plate, so that the height of the cross-shaped ribs and the thickness of the wing plate are greater than the thickness of the top plate, so as to improve the strength of the heavy raised floor in the middle. For example, 21 other sub-regions are separated by the second rib, the third rib, the fourth rib, the fifth rib and the sixth rib in the well-shaped rib, and there are nine perforations in each of the sub-regions , but the perforation is not formed in the sub-region of the central part of the well-shaped rib.

As can be seen from the above, in the heavy-duty raised floor of the present invention, the height of the main ribs of the rib structure relative to the honeycomb side is at least 25 mm to enhance the structural strength of the heavy-duty raised floor (such as at least 1500 kilograms of machine equipment), so compared with the conventional technology, the heavy-duty raised floor can bear heavier machine equipment in the semiconductor manufacturing process, so as to avoid the problem of the heavy-duty raised floor being broken during use.

The implementation of the present invention is described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to match the content disclosed in the specification, for the understanding and reading of those familiar with this technology, and are not used to limit the implementation of the present invention Therefore, it has no technical substantive meaning. Any modification of structure, change of proportional relationship or adjustment of size shall still fall within the scope of this invention without affecting the effect and purpose of the present invention. The technical content disclosed by the invention must be within the scope covered. At the same time, terms such as "upper", "lower", "left", "right" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the implementation of the present invention. Changes or adjustments in the scope, and their relative relationships, without substantial changes in the technical content, should also be regarded as the scope of the present invention that can be implemented.

Fig. 1A, Fig. 1B, Fig. 1C and Fig. 1D are schematic views of the first embodiment of the heavy-duty raised floor 1 of the present invention. The heavy-duty raised floor 1 of the present embodiment is used for bearing heavier loads, and its bearing load is about 1500 kilograms.

The heavy-duty elevated floor 1 is provided with a top plate 10 and a rib structure 1a arranged on the top plate 10 .

Said top plate 10 has opposite ground side 10a and honeycomb side 10b, and said honeycomb side 10b is respectively provided with said rib structure 1a on longitudinal and transverse direction, so as to form between said longitudinal and transverse rib structure 1a For the plurality of recesses S, Fig. 1C only shows the longitudinal rib structure 1a, and the transverse rib structure 1a is the same as the longitudinal rib structure 1a, so the section of the transverse rib structure 1a is omitted.

In this embodiment, the top plate 10 is roughly rectangular, such as a square plate, its length L is 600mm and thickness t0 is 3mm, and a wing plate 1d is formed around the top plate 10 (thickness t1 is 6㎜, which is greater than the thickness t0 of the top plate 10), and there are feet 1b formed on the four corners of the top plate 10, the bottom of which is mouth-shaped convex (or mouth-shaped concave), for Fix a support tripod (not shown). For example, the feet 1b are used to adjust the total height H of the heavy-duty raised floor 1 so that multiple heavy-duty raised floors 1 are located at the same level.

Furthermore, the ground side 10a is a flat surface, and the recesses S are arranged in an array to form a plurality of thimble positions 1c (approximately in a square area formed by every four recesses S) on the honeycomb side 10b. The corner of the above) honeycomb structure.

The rib structure 1a is defined in sequence from the edge of the top plate 10 to the middle (or from the left and right sides to the middle as shown in Figure 1B and Figure 1C ) with a first rib 11, a second rib 12, and a third rib 13. The fourth rib 14, the fifth rib 15, the sixth rib 16, and the seventh rib 17, and the heights h1-h7 of the first to seventh ribs 11-17 relative to the honeycomb side 10b are all at least 25 mm (㎜), so the first to seventh ribs 11 to 17 are used as main ribs, and the first to sixth ribs 11 to 16 are left and right symmetrical on the basis of the seventh rib 17 (well-shaped rib) ( Or as shown in Figure 1B, the upper and lower symmetrical) distribution, so that the distance w between the second rib 12, the third rib 13, the fourth rib 14, the fifth rib 15, the sixth rib 16 and the seventh rib 17 is 48㎜.

In this embodiment, the first ribs 11 are formed on the edge of the top plate 10 to become the side ribs of the heavy raised floor 1, and serve as the frame of the heavy raised floor 1 for fixing the feet 1b. For example, the height h1 of the first rib 11 relative to the honeycomb side 10b is 50mm (equal to the height h2, h7 of the second and seventh ribs 12, 17 relative to the honeycomb side 10b) is greater than the third to sixth The height h3~h7 of the ribs 13~16 relative to the honeycomb side 10b, and the height T of the first rib 11 and the top plate 10 (that is, the height of the first rib 11 relative to the ground side 10a) is 53mm (ie T=h1+t0), and the total height H of the base 1b, the first rib 11 and the top plate 10 (ie the foot height of the heavy raised floor 1) is 55 mm.

Furthermore, the heights h2-h7 of the second to seventh ribs of the rib structure 1a can be the same or different according to requirements, and the main ribs between the first rib 11 and the recess S in the middle (ie the second to the seventh ribs) The arrangement of the seventh ribs (12~17) is symmetrical according to the height, as shown in Figure 1C. For example, the height h2 of the second rib 12 relative to the honeycomb side 10b is 50mm, the height h3 of the third rib 13 relative to the honeycomb side 10b is 25mm, and the height h4 of the fourth rib 14 relative to the honeycomb side 10b is 38㎜, the height h5 of the fifth rib 15 relative to the honeycomb side 10b is 38㎜, the height h6 of the sixth rib 16 relative to the honeycomb side 10b is 25㎜, and the height of the seventh rib 17 relative to the honeycomb side 10b h7 is 50㎜, wherein, the two seventh ribs 17 in the longitudinal and transverse directions form a well-shaped rib to divide the heavy raised floor 1 into four areas, and the second rib 12 and the second rib adjacent to each area Between the three ribs 13, the fourth rib 14, the fifth rib 15 and the sixth rib 16, 25 sub-regions are formed, each sub-region has a concave portion S, and forms another pattern in the central part of the well-shaped rib. Recess R. Further, the thickness of the top plate 10 at the recess R can be greater than the thickness t0 of the top plate 20 at other places (that is, the thickness of the top plate 20 at the recess R is thickened to 6mm) or be the same as that of the top plate 20. The thickness t0 of the board 10 is the same, and the cross-shaped rib 17a is arranged in the recess R, and its height h0 relative to the honeycomb side 10b is 14 mm (it is greater than the thickness t0 of the top board 10) to improve the heavy raised floor 1 Compressive strength at the middle.

Moreover, the widths d1-d7 of the ribs can be the same or different according to requirements, as shown in FIG. 1C, and the widths d2-d7 of the ribs between the first rib 11 and the middle recess R are symmetrically designed. For example, the width d1 of the first rib 11 is 8.5 mm, the width d2 of the second rib 12 is 5 mm, the width d3 of the third rib 13 is 3.5 mm, the width d4 of the fourth rib 14 is 3.2 mm, and the width d4 of the fifth rib 15 The width d5 of the sixth rib 16 is 3.2 mm, the width d6 of the sixth rib 16 is 3.5 mm, and the width d7 of the seventh rib 17 is 5 mm.

In addition, the rib structure 1a can add a plurality of auxiliary ribs 18 whose volume is much smaller than the main rib, as shown in Figure 1C, the height h8 (for example, at least 8 mm) relative to the honeycomb side 10b is lower than the main rib The height h1~h7 relative to the honeycomb side 20b, and the width d8 is at least 2.5mm. For example, the auxiliary ribs 18 are correspondingly formed in each of the recesses S, and extend along a single direction without crossing each other. A single recess S as shown in FIG. 1C is provided with two parallel auxiliary ribs 18 .

It can be seen from the above that the thickness t0 of the top plate 10 of the heavy-duty raised floor 1 is relatively small, so as to save material and reduce weight.

Fig. 2A, Fig. 2B and Fig. 2C are schematic diagrams of the second embodiment of the heavy-duty raised floor 2 of the present invention. The heavy-duty raised floor 2 of this embodiment is also used to carry heavier loads, and its load exceeds 3000 kilograms, and its difference from the first embodiment lies in the change of the local height of the rib structure 2a, so the same parts will not be repeated below. .

In this embodiment, the thickness t0 of the top plate 20 is 4.5mm, the height h1 of the first rib 21 relative to the honeycomb side 20b is at least 48.5mm, and the height of the first rib 21 and the top plate 20 is T (that is, the height of the first rib 21 relative to the ground side 20a) is at least 53mm, and the total height H of the foot seat 2b, the first rib 21 and the top plate 20 is at least 55mm, wherein the The thickness t1 of the wing plate 2d is at least 6 mm, the first rib 21 is formed on the edge of the top plate 20 to become the side rib of the heavy raised floor 2, and serves as the frame of the heavy raised floor 2, and the first to The sixth ribs 21 to 26 are distributed bilaterally symmetrically (or vertically symmetrically as shown in FIG. 2B ) based on the seventh rib 27 .

Furthermore, the heights h2-h7 of the second to seventh ribs 22-27 relative to the honeycomb side 20b are all at least 48.5 mm, that is, the first to seventh ribs 21-27 are of the same height. On the other hand, the thickness of the top plate 20 at the recess R is increased to at least 7.5mm (that is, greater than the thickness t0 of the top plate 20 at other places), and the recess R is equipped with a cross-shaped rib 27a, which The height h0 relative to the honeycomb side 20b is at least 15mm (which is greater than the thickness t0 of the top plate 20), so as to increase the compressive strength of the heavy raised floor 2 in the middle.

Moreover, the widths d1-d7 of the ribs can be the same or different according to requirements, as shown in FIG. 2C. For example, the width d1 of the first rib 21 is 9.5mm, the width d2 of the second rib 22 is 8.5mm, the widths d3~d6 of the third to sixth ribs 23~26 are all 4mm, and the width of the seventh rib 27 d7 is 6 mm.

In addition, the height h8 of the auxiliary rib 28 relative to the honeycomb side 20b is at least 6mm, and the width d8 is at least 2.5mm.

It can be seen from the above that the heights h1-h7 of the rib structure 2a are approximately equal to facilitate the balance of weight distribution.

Fig. 3A, Fig. 3B and Fig. 3C are schematic diagrams of the third embodiment of the heavy-duty raised floor 3 of the present invention. The heavy-duty raised floor 3 of this embodiment is also used to carry heavier loads, and its load exceeds 3000 kilograms, and the difference between it and the second embodiment lies in the change of the local height of the rib structure 3a, so the same parts will not be repeated below.

In this embodiment, the thickness t0 of the top plate 30 is 4.5mm, the height h1 of the first rib 31 relative to the honeycomb side 30b is 55.5mm, and the height sum of the first rib 31 and the top plate 30 is T (that is, the height of the first rib 31 relative to the ground side 30a) is 60mm, and the total height H of the foot seat 3b, the first rib 31 and the top plate 30 is 62mm, and the wing plate 3d The thickness t1 is 6mm, the first rib 31 is formed on the edge of the top plate 30 to become the side rib of the heavy raised floor 3, and serves as the frame of the heavy raised floor 3, and the first to sixth ribs 31 The distribution of ~36 is bilaterally symmetrical (or vertically symmetrical as shown in FIG. 3B ) based on the seventh rib 37 .

Moreover, in the rib structure 3a, as shown in FIG. 3C, the height h2 of the second rib 32 relative to the honeycomb side 30b is 55.5mm, and the height h3 of the third to seventh ribs 33-37 relative to the honeycomb side 30b ~h7 are both 51㎜. On the other hand, the thickness of the top plate 30 at the recess R is increased to 7.5 mm (that is, greater than the thickness t0 of the top plate 30 at other places), and a cross-shaped rib 37a is arranged in the recess R, which is relatively The height h0 of the honeycomb side 30b is 15mm (which is greater than the thickness t0 of the top plate 30), so as to increase the compressive strength of the heavy raised floor 3 in the middle.

In addition, the widths d1-d7 of the ribs can be the same or different according to requirements, as shown in FIG. 3C. For example, the width d1 of the first rib 31 is 9.5mm, the width d2 of the second rib 32 is 9mm, the widths d3~d6 of the third to sixth ribs 33~36 are all 3.5mm, and the width of the seventh rib 37 d7 is 5 mm.

In addition, the height h8 of the auxiliary rib 38 relative to the honeycomb side 10b is at least 6 mm, and the width d8 thereof is 2.5 mm.

It can be known from the above that the partial heights h3-h7 of the rib structure 3a are approximately equal to facilitate balanced weight distribution.

Fig. 4A, Fig. 4B, Fig. 4C and Fig. 4D are schematic views of the fourth embodiment of the heavy-duty raised floor 4 of the present invention. The difference between this embodiment and the above-mentioned embodiments lies in the addition of perforations, so the similarities will not be repeated below.

As shown in Fig. 4A, Fig. 4B, Fig. 4C and Fig. 4D, based on the first embodiment, the heavy-duty elevated floor 4 forms a plurality of perforations 40 connecting the ground side 10a and the honeycomb side 10b on the top plate 10, and uses The seventh rib 17 (the well-shaped rib) divides the honeycomb side 10b into four regions, and each region forms 25 sub-regions (the concave portion S). In the well-shaped rib, the ribs (the second Rib 12, third rib 13, fourth rib 14, fifth rib 15 and sixth rib 16) can be separated by 21 further sub-regions (the recesses R, S) so that each sub-region has nine perforations 40, and a unidirectional auxiliary rib 18 is provided between three adjacent perforations 40 in each sub-region to strengthen the strength of the top plate 10 between the perforations 40, and it is easier to make concave holes during the die-casting process, But the perforation 40 is not formed in the sub-region (the concave portion R) of the central part of the well-shaped rib.

In this embodiment, the positions of the through holes 40 are arranged corresponding to the recesses S. As shown in FIG. For example, nine through holes 40 are formed on each concave portion S, and the nine through holes 40 are arranged in an array, so that each row has three through holes 40 .

Therefore, the recess R of the central portion of the seventh rib 17 (well-shaped rib) may not be provided with the perforation 40, and the height h0 of the inner cross-shaped rib 17a relative to the honeycomb side 10b is greater than the thickness t0 of the top plate 10 , to improve the intensity of this heavy raised floor 4.

It should be understood that the heavy-duty raised floors 2 and 3 of the second and third embodiments can also form these perforations 40 in the recesses S thereof.

In summary, the heavy-duty raised floor 1, 2, 3, 4 of the present invention is mainly due to the fact that the ribs of the rib structure 1a, 2a, 3a have heights h1~h7 of the ribs relative to the honeycomb sides 10b, 20b, 30b that are at least 25 mm to increase the structural strength of the heavy-duty raised floor 1, 2, 3, 4, so that the heavy-duty raised floor 1, 2, 3, 4 can bear the heavier machine equipment in the semiconductor process, so as to avoid the heavy-duty raised floor 1, 2, 3, 4 are broken during use. Further, the height h1~h7 and the width d1~d7 of the ribs are adjusted according to the bearing load of the heavy-duty raised floor 1, 2, 3, 4, thereby saving the material and lightening of the heavy-duty raised floor 1, 2, 3, 4 weight.

Furthermore, through the design of the auxiliary ribs 18, 28, 38, the structural strength of the heavy raised floors 1, 2, 3, 4 can be further improved.

The above-mentioned embodiments are used to illustrate the principles and effects of the present invention, but not to limit the present invention. Any person skilled in the art can modify the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the rights of the present invention should be listed in the scope of the patent application described later.

1,2,3,4: Heavy duty raised floor 1a, 2a, 3a: Rib structure 1b, 2b, 3b: feet 1c: thimble position 1d, 2d, 3d: wing plate 10,20,30: top plate 10a, 20a, 30a: ground side 10b, 20b, 30b: Honeycomb side 11,21,31: first rib 12,22,32: second rib 13,23,33: third rib 14,24,34: Fourth rib 15,25,35: fifth rib 16,26,36: sixth rib 17,27,37: seventh rib 17a, 27a, 37a: Cross-shaped ribs 18,28,38: Auxiliary ribs 40: perforation d1~d8: width H: total height h0~h8: height L: Length R, S: concave part T: height and t0, t1: thickness w: interval distance

FIG. 1A is a three-dimensional schematic view of the first embodiment of the heavy-duty raised floor of the present invention.

FIG. 1B is a front plan view of FIG. 1A.

FIG. 1C is a cross-sectional view of FIG. 1B along line C-C in one of the directions.

FIG. 1D is a three-dimensional schematic view of another viewing angle of FIG. 1A .

Fig. 2A is a three-dimensional schematic view of the second embodiment of the heavy-duty raised floor of the present invention.

FIG. 2B is a front plan view of FIG. 2A.

FIG. 2C is a cross-sectional view along line C-C of FIG. 2B along one of the directions.

Fig. 3A is a three-dimensional schematic view of the third embodiment of the heavy-duty raised floor of the present invention.

FIG. 3B is a front plan view of FIG. 3A.

FIG. 3C is a cross-sectional view of FIG. 3B along line C-C in one of the directions.

Fig. 4A is a three-dimensional schematic diagram of the fourth embodiment of the heavy-duty raised floor of the present invention.

FIG. 4B is a front plan view of FIG. 4A.

FIG. 4C is a cross-sectional view along line C-C of FIG. 4B along one of the directions.

FIG. 4D is a perspective view of another viewing angle of FIG. 5A .

1: Heavy duty raised floor

1a: Rib structure

1b: foot seat

1d: wing plate

10:Top plate

10a: Ground side

10b: Honeycomb side

11: First rib

12: Second rib

13: Third rib

14: Fourth rib

15: Fifth rib

16: Sixth rib

17: seventh rib

17a: Cruciform ribs

18: auxiliary rib

d1~d8: width

H: total height

h0~h8: height

R, S: concave part

T: height and

t0, t1: thickness

Claims (13)

A heavy-duty raised floor comprising: a top plate having opposing ground sides and a honeycomb side; and a rib structure disposed on the honeycomb side of the top plate to form a plurality of recesses, wherein the rib structure is defined by the top plate There are first ribs, second ribs, third ribs, fourth ribs, fifth ribs, sixth ribs and seventh ribs defined in order from the edge to the middle, and the first to seventh ribs are used as main ribs. The height relative to the side of the hive is at least 25 mm. The heavy-duty raised floor according to claim 1, wherein the plurality of recesses are arranged in an array to form a honeycomb structure on the side of the honeycomb. The heavy-duty raised floor according to claim 1, wherein the first rib is formed on the edge of the top plate to become a side rib of the heavy-duty raised floor, and serves as a frame of the heavy-duty raised floor for fixing feet. The heavy-duty raised floor as described in Claim 1, wherein the sum of the heights of the first rib and the top plate is 51 to 62 mm, and the thickness of the top plate is 2.7 to 4.8 mm. The heavy-duty raised floor according to claim 1, wherein the width of the first rib is 8.3 to 9.8 mm. The heavy-duty raised floor according to claim 1, wherein the heights of the second to seventh ribs relative to the side of the honeycomb are 25 to 56.5 mm. The heavy-duty raised floor as described in claim 1, wherein the widths of the second to seventh ribs are 3.0 to 9.4 mm. The heavy-duty raised floor as described in Claim 1, wherein, the rib structure further includes a plurality of auxiliary ribs with a height less than 25 mm, and the plurality of auxiliary ribs are correspondingly formed in each of the recesses, so that a single recess can be The plurality of auxiliary ribs are arranged. The heavy-duty raised floor according to Claim 8, wherein the plurality of auxiliary ribs extend in a single direction without interlacing each other. The heavy-duty raised floor as claimed in claim 8, wherein the height of the auxiliary rib relative to the side of the honeycomb is at least 6mm, and the width thereof is at least 2.5mm. The heavy-duty raised floor as described in claim 1, wherein a plurality of perforations connecting the ground side and the honeycomb side are formed on the top plate, and the positions of the plurality of perforations correspond to the plurality of recesses, and three adjacent perforations There are unidirectional auxiliary ribs between them. The heavy-duty raised floor as described in Claim 1, wherein, the rib structure forms a well-shaped rib with two seventh ribs in the longitudinal and transverse directions, so as to divide the heavy-duty raised floor into four areas, and the four 25 subregions are formed between the adjacent second ribs, third ribs, fourth ribs, fifth ribs and sixth ribs in the region, each of which has a recess, and the first to sixth ribs are The other concave part is symmetrically distributed on the basis of the well-shaped rib and is formed at the central part of the well-shaped rib formed by the seventh rib. The thickness of the concave part is thicker than the thickness of the top plate. Cross-shaped ribs are arranged inside, and a wing plate is formed around the top plate, so that the height of the cross-shaped ribs and the thickness of the wing plate are greater than the thickness of the top plate, so as to improve the strength of the heavy raised floor in the middle . The heavy-duty raised floor as described in claim 12, wherein 21 other sub-regions are separated in the well-shaped ribs by the second rib, the third rib, the fourth rib, the fifth rib and the sixth rib, And there are nine perforations in each sub-region, but the perforation is not formed in the sub-region of the central part of the well-shaped rib.

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