KR20170084614A

KR20170084614A - Assembly type steel pallet

Info

Publication number: KR20170084614A
Application number: KR1020160003862A
Authority: KR
Inventors: 이희만
Original assignee: 이희만; 삼정캐리월드(주)
Priority date: 2016-01-12
Filing date: 2016-01-12
Publication date: 2017-07-20
Also published as: KR101810977B1

Abstract

The present invention relates to a prefabricated metal pallet, and more particularly to a prefabricated metal pallet which can minimize the weight of a pallet formed by joining steel frames and increase the supporting force while simplifying assembly and disassembly. The present invention relates to a prefabricated steel pallet.
The present invention relates to a prefabricated iron-on-steel pallet, comprising: an outer frame of 'ㅁ' shape having a plurality of engaging grooves formed on an upper surface or a lower surface thereof; and a plurality of transverse members and longitudinal members provided to intersect each other on the inner side of the outer frame Shaped supporting member connected between the upper and lower plates and the coupling groove formed in the outer frame of the upper plate and the lower plate to support the upper plate.

Description

Assembly type steel pallet

The present invention relates to a prefabricated metal pallet, and more particularly to a prefabricated metal pallet which can minimize the weight of a pallet formed by joining steel frames and increase the supporting force while simplifying assembly and disassembly. The present invention relates to a prefabricated steel pallet.

Generally, a pallet disposed at the lower part of a bundle bundle for facilitating the transportation of forklifts is made of wood, synthetic resin, etc., and has been widely used for transportation of cargoes at most factories or quays.

However, the conventional pallet described above has a problem in that the volume of the empty pallet itself except for the cargo is formed to be too large, which makes the volume of the cargo unnecessarily unnecessarily large, resulting in an excessive cost of logistics.

In addition, the pallet of wood material can be produced various kinds of germs, which is unsafe for hygiene, and a pallet made of plastic or synthetic resin that can replace it is advantageous in that the production cost is low. However, So that it is practically impossible to produce pallets of various sizes.

In recent years, in order to compensate for this problem, conventional steel pallets have been produced, but the number of parts has increased, resulting in problems such as an increase in production costs and difficulty in automating mass production, and the assembled piece bolts are easily relaxed due to vibration during prolonged use And the shortage of the service life of the pallet has shortened. After that, the entire pallet has been integrally manufactured up to the leg portion. However, various difficulties such as the excessive installation of the equipment cost are appearing. In order to achieve the purpose of the pallet, And so on.

In addition, conventionally, since the middle plate for joining the upper plate and the lower plate is manufactured by welding, even when the pallet is not used, it must be transported and stored in the assembled state. Therefore, the pallet is heavy and bulky, So that it is not easy to handle.

As a technique for solving such a problem, Korean Patent Registration No. 10-1222932 discloses a prefabricated pallet, which is a registered patent of the present applicant, and its main technical structure is a prefabricated pallet comprising a top plate, Wherein the intermediate support is slidably fitted between the upper plate and the lower plate.

That is, the above-mentioned prior art is characterized in that the middle plate is fitted between the upper plate and the lower plate by a sliding method so that the upper plate and the lower plate constituting the pallet can be easily assembled by a simple structure. However, Even if pallets are made of a single piece of steel plate, the pallets may be deformed when the heavy cargo is continuously transported, and the rim of the pallet may be sharpened, .

In addition, the conventional steel pallet has been made into a roll structure by applying a lot of curvature to the plate-shaped plate in order to strengthen the supporting force while being made to have a light structure. However, There is a problem that the outer portion of the pallet becomes very vulnerable to damage.

1. Korean Registered Patent No. 10-1222932 (issued on March 31, 2013)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the conventional art as described above, and it is an object of the present invention to provide a pallet comprising a top plate, a bottom plate and a supporting member constituting a pallet by using a pipe or rod- And the support force can be strengthened while minimizing the size of the pallet.

It is another object of the present invention to provide a prefabricated metal pallet for transporting an upper plate, a lower plate, and a support member, respectively, so that the pallet can be assembled and used immediately in the field so that transportation costs can be reduced.

Further, according to the present invention, all parts of the outer frame are rounded to prevent injury to the operator and damage to the load due to the sharpness of the frame, and an auxiliary frame is provided on the top plate to prevent the loaded goods from being separated The present invention also provides a prefabricated metal pallet that can be selectively assembled with a flat pallet and a box pallet as needed.

According to an aspect of the present invention,

A prefabricated metal pallet comprising: an outer frame of 'ㅁ' shape having a plurality of engaging grooves formed on an upper surface or a lower surface thereof; and a plurality of transverse members and longitudinal members installed to intersect each other on the inner side of the outer frame, And a support member in the form of a bar, which is connected between the lower plate and the coupling groove formed in the outer frame of the upper plate and the lower plate to support the upper plate.

In this case, the outer frame, the horizontal member, and the vertical member are formed by a square pipe.

The supporting member may include first and second engaging portions respectively inserted into the engaging grooves formed in the outer frames of the upper plate and the lower plate and a supporting bar connected between the first and second engaging portions. .

The first and second engaging portions include a first lid configured to surround an end portion of the support rod, a second lid coupled to the inside of the first lid, and a second lid provided between the first lid and the second lid, And a fixing member for fixing the fixing member.

In addition, the fixing member is formed with a through hole having a sawtooth circumference, and both side ends of the support shaft are formed with coupling grooves engaged with the through holes.

The first lid and the second lid are provided with first and second through holes through which the support rods are inserted. The first lid and the inner surface of the second lid have a first inclined surface and a second inclined surface, The first inclined surface is formed with an inclined surface and the second inclined surface is formed with a concave groove at the end of the first inclined surface so that the engaging step is engaged with the end of the second inclined surface.

Further, a plurality of horizontal frames are provided between the outer frame and the vertical member of the upper plate and between the vertical member and the vertical member.

The cover plate may further include a cover plate disposed on the upper surface of the upper plate.

At this time, an auxiliary frame having a 'C' -shaped cross section including a horizontal part and a side wall is installed on the upper edge of the cover plate.

The angle between the horizontal portion and the side wall is an obtuse angle.

In addition, the horizontal portion and the side wall have bent portions bent inward, and at least one forceps is formed on the side walls.

The horizontal portion and the side wall are formed in two layers, and a space portion is formed inside the side wall.

In addition, the auxiliary frame is formed in a double structure by bending a single plate, and a reinforcing portion is formed at an upper end of the side wall so that both side ends of the plate are bent to be engaged with each other.

According to the present invention, an upper plate, a lower plate, and a supporting member constituting the pallet are formed by using a pipe or a rod-shaped frame or members, thereby minimizing the weight of the pallet and enhancing the supporting force.

In addition, according to the present invention, the upper plate, the lower plate, and the support member are respectively transported to be assembled immediately on site, and the volume of the upper plate, the lower plate, and the support member is minimized, .

In addition, according to the present invention, by rounding all the parts constituting the outer frame, it is possible to prevent injury of the operator and damage to the load due to the sharpness of the frame, and to prevent the falling of the loaded goods by installing a sub- And at the same time, the pallet can be selectively assembled with a flat pallet and a box pallet, if necessary.

1 is a perspective view showing a first embodiment of a prefabricated steel pallet according to the present invention;
Figure 2 is an exploded perspective view of the present invention shown in Figure 1;
3 is an exploded perspective view of the support member of the present invention shown in Fig.
FIG. 4 is a partial cross-sectional view showing the support member in detail in the present invention shown in FIG. 1; FIG.
5 is a perspective view showing a second embodiment of a prefabricated steel pallet according to the present invention.
6 (a) and 6 (b) are a perspective view and a side view showing a third embodiment of the prefabricated metal pallet according to the present invention.
7 (a) and 7 (b) are a perspective view showing a fourth embodiment of the assembled metal pallet according to the present invention and a sectional view of the auxiliary frame.
8A and 8B are a partial perspective view and a cross-sectional view showing another embodiment of the auxiliary frame of the present invention shown in Fig. 7;
9A and 9B are a cross-sectional view and a use state view showing still another embodiment of the subframe according to the present invention shown in FIG. 7;
10 is a perspective view showing a state in which the upper plate and the lower plate are laminated in the present invention shown in Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a prefabricated steel pallet according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a perspective view showing a first embodiment of a prefabricated steel pallet according to the present invention, Fig. 2 is an exploded perspective view of the present invention shown in Fig. 1, Fig. 3 is an exploded perspective view of a support member of the present invention shown in Fig. 1 FIG. 5 is a perspective view showing a second embodiment of the prefabricated steel pallet according to the present invention, and FIGS. 6 (a) and 6 (b) 7A and 7B are a perspective view and a perspective view showing a fourth embodiment of the prefabricated metal pallet according to the present invention, and FIGS. 7A and 7B are a perspective view and a side view showing a third embodiment of the prefabricated metal pallet according to the present invention, 8 (a) and 8 (b) are a partial perspective view and a cross-sectional view showing another embodiment of the auxiliary frame of the present invention shown in Fig. 7, and Figs. 9 (a) Sectional view showing still another embodiment of the auxiliary frame in the present invention And Fig. 10 is a perspective view showing a state in which the upper plate and the lower plate of the present invention shown in Fig. 1 are laminated.

The present invention relates to a prefabricated metal pallet (10) capable of strengthening its supporting force while minimizing the weight of a pallet formed by joining steel frames and being easily assembled and separated by a simple structure, As shown in Fig. 1, the constitution is largely composed of an upper plate 100, a lower plate 200, and a supporting member 300.

More specifically, the upper plate 100 serves to support a load placed on the upper portion. The upper plate 100 includes a 'U' shaped outer frame 110 constituting a rim portion, A plurality of transverse members 120 and a longitudinal member 130 which are installed to intersect with each other.

That is, a frame of the upper plate 100 is formed by using the outer frame 110, and a plurality of the horizontal members 120 and the vertical members 130 are intersected with each other in a cross shape on the inner side of the outer frame 110 So as to support the load placed on the upper part.

The longitudinal members 130 may be divided into a plurality of members provided between the lateral members 120 or the longitudinal members 130 may be divided into a plurality of And the lateral members 120 are separated from each other by a plurality of members provided between the longitudinal members 130 so that the upper frame 130 composed of the outer frame 110, the lateral members 120 and the longitudinal members 130 100 are made to exist on the same plane as a whole, as shown in Fig. 10, when they are stacked for transportation to a worksite or for transportation such as export for sale, the volume thereof can be minimized, .

The outer frame 110, the horizontal member 120, and the vertical member 130 are formed of hollow rectangular pipes whose corners are rounded to minimize the weight of the upper panel 100 And each corner portion of the outer frame 110 having a '?' Shape is also formed in a round shape so as to prevent the occurrence of injury of the operator due to the sharpness of the corner portion.

A plurality of coupling grooves (not shown) are spaced apart from each other by a predetermined distance on the lower surface of the outer frame 110. The first coupling portion 310 of the support member 300, which will be described later, .

At this time. The number of the supporting members 300 may be increased by forming the coupling groove at the intersection of the lateral member 120 and the longitudinal member 130 for enhancing the supporting force of the upper plate 100. [

The lower plate 200 is connected to the lower portion of the upper plate 100 by the support member 300 to support the pallet 10 so that the pallet 10 can be stably placed on the ground. Structure.

In other words, the lower plate 200 also includes a 'U' shaped outer frame 210 and a plurality of horizontal members 220 and vertical members 230 installed to cross each other on the inner side of the outer frame 210 A plurality of coupling grooves 212 are formed on the upper surface of the outer frame 210 such that a second coupling portion 320 of the support member 300 to be described later is inserted.

2, a coupling groove 212 may be formed at an intersection of the transverse member 220 and the longitudinal member 230 so that the supporting member 300 may be installed.

The outer frames 110 and 210 and the horizontal members 120 and 130 and the vertical members 130 and 230 constituting the upper plate 100 and the lower plate 200 may be coupled to each other by spot welding or the like.

The support member 300 is vertically connected between the upper plate 100 and the lower plate 200 to support the upper plate 100. The support member 300 has a round rod shape and has both ends connected to the upper plate 100, (Not shown) formed at the intersection of the outer frames 110 and 210 of the upper and lower plates 200 and the lateral members 120 and 220 and the longitudinal members 130 and 230.

3, the supporting member 300 includes first and second engaging portions 310 and 320 and a supporting bar 330. The first and second engaging portions 310 and 320 include (Not shown) formed at the intersections of the outer frames 110 and 210 of the upper plate 100 and the lower plate 200 and the lateral members 120 and 220 and the longitudinal members 130 and 230, 300 can be coupled between the upper plate 100 and the lower plate 200. The support rod 300 is connected between the first and second coupling parts 310, ).

The first and second couplers 310 and 320 may include first and second covers 312 and 322 and second and third covers 314 and 324 and fixing members 316 and 326. The second lids 314 and 324 are inserted into the coupling grooves 212 of the first and second lids 312 and 321 and the lower plate 200 so as to surround both ends of the support rod 330, 322 and the fixing members 316, 326 while supporting both side ends of the support bar 330 and supporting the side surfaces of the first lids 312, 322 to the first lids 312, 322.

The fixing members 316 and 326 are inserted between the first and second covers 312 and 322 and the second covers 314 and 324 to fix the support bar 330.

First and second through holes 312a, 322a, 314a, and 324a are formed in the first and second covers 312 and 322 and the second covers 314 and 324, respectively, to which both ends of the support bar 330 are inserted. 1 and the second through holes 312a, 322a, 314a, and 324a are formed to have the same inner diameter as that of the support rods 330 at both ends so as to fix the support rods 330 without shaking.

The inner surfaces of the second covers 314 and 324 which are coupled to cover the outer surfaces of the first and second covers 312 and 322 and the first and second covers 312 and 322 are provided with first and second inclined surfaces 312b, The first and second inclined surfaces 312b, 322b, 314b, and 324b having downward inclination toward the inside of the second covers 314 and 324 are formed, and the first and second covers 312 and 322, 322c are protruded from the ends of the first inclined surfaces 312b and 322b and the ends of the second inclined surfaces 314b and 324b The first lids 312 and 322 and the second lids 314 and 324 can be coupled to each other by forming recessed grooves 314c and 324c to be engaged with the latching protrusions 312c and 322c.

Through holes 316a and 326a through which both ends of the support bar 330 are respectively inserted are formed at the center of the fixing members 316 and 326 fixed between the first and second lids 312 and 324 and the second lids 314 and 324, The diameters of the through holes 316a and 326a are set to be slightly smaller than the diameters of both ends of the support bar 330. The diameter of the through holes 316a and 326a .

Coupling grooves 332 are formed in the outer circumferential surfaces of both ends of the support bar 330 to engage with the through holes 316a and 326a formed in the fixing members 316 and 326.

That is, the fixing members 316 and 326 are made of a metal material having elasticity so that the diameters of the through holes 316a and 326a formed in the shape of the teeth 316b and 326b of the circumference can be varied, The through holes 316a and 326a are opened by the force applied by the support bar 330 so that the support bar 330 is inserted through the through holes 316a and 326a, And the through holes 316a and 326a of the teeth 316b and 326b are engaged with the coupling grooves 332 of the support bar 330 so that the support bar 330 can be fixed.

The upper and lower plates 100 and 200 may be provided with an engagement groove 212 not shown between the upper plate 100 and the lower plate 200 to provide the first and second engagement portions 310 and 320, The first lids 312 and 322 and the fixing members 316 and 326 and the second lids 314 and 324 are sequentially inserted into the first lids 312 and 322. At this time, The second lids 314 and 324 are coupled to enclose the side surfaces of the first lids 312 and 322 by the inclined surfaces 312b and 322b and the second inclined surfaces 314b and 324b formed on the inner surfaces of the second lids 314 and 324, The first lids 312 and 322 and the second lids 314 and 324 are engaged with each other while the engaging protrusions 312c and 322c formed on the first lids 312 and 322 are engaged with the recessed grooves 314c and 324c formed on the second lids 314 and 324, And the fixing members 316 and 326 are fixed between the first covers 312 and 322 and the second covers 314 and 324.

At this time, a plurality of wedge portions 314d and 324d are protruded from the lower end outer surface of the second covers 314 and 324 so that the second covers 314 and 324, which are inserted into the coupling grooves (not shown) And the like.

That is, the wedge portions 314d and 324d are formed to have a downward inclination toward the entering direction of the second lids 314 and 324 so that the second lids 314 and 324 can easily enter the inside of the coupling groove (not shown) While preventing the second covers 314 and 324, which are inserted and coupled to the coupling groove (not shown), from being detached.

A head portion of a bolt (not shown) is positioned on the upper end of the first lid 312 or 322 so as to be engaged with the inside of the first lid 312 or 322 and the threaded portion protrudes outside the first lid 312 or 322 A bolt insertion hole 312d and a bolt insertion hole 312d may be formed on the inner side of the coupling groove 212 The first covers 312 and 322 may be fixedly installed inside the coupling grooves 212 (not shown) by forming female threads (not shown).

When the end of the support rod 330 is inserted through the second through holes 314a and 324a formed in the second lids 314 and 324, the upper ends of the support bars 330 are engaged with the teeth 316b and 316b formed on the fixing members 316 and 326, 326b through the through holes 316a, 326a and the fastening groove 332 formed in the support bar 330 is inserted into the through holes 316a, 326b of the teeth 316b, 326b, The installation of the support member 330 including the first and second coupling parts 310 and 320 and the support bar 330 is completed.

5, the transverse frame 140 may be further provided on the top plate 100, and the transverse frame 140 may be formed of a metal plate, And is connected between the outer frame 110 and the vertical member 130 and between the vertical member 130 and the adjacent vertical member 130 to improve the supporting force of the upper plate 100.

At this time, the horizontal frame 140 may be fixedly installed between the outer frame 110 and the vertical member 130 and between the vertical member 130 and the adjacent vertical member 130 by spot welding or the like. And may be formed in a concavo-convex structure to strengthen the support force and prevent deformation due to the load.

6 (a) and 6 (b), according to another embodiment of the assembled metal pallet 10 according to the present invention, the cover plate 150 installed on the upper portion of the upper plate 100 The cover plate 150 is configured to cover the upper surface of the upper plate 100 and the edge portion is bent downward to enclose the side surface of the outer frame 110.

That is, the cover plate 150 tightens the upper surface of the upper plate 100, thereby enhancing the supporting force of the upper plate 100 and enabling the loading of articles having a smaller volume so that the articles to be loaded on the pallet 10 become more diverse And an auxiliary frame 160, which will be described later, can be installed on the upper plate 100.

According to another embodiment of the prefabricated steel pallet 10 according to the present invention, as shown in FIG. 7A, an auxiliary frame 160 is installed at the upper edge of the cover plate 150 The auxiliary frame 160 serves to prevent the load placed on the upper plate 100 from being detached from the pallet 10 and to utilize the present invention as a box pallet.

More specifically, the auxiliary frame 160 is formed with a horizontal portion 162 and a side wall 164 and has a cross-section of an "a" shape. The horizontal portion 162 is formed in the upper portion of the cover plate 150 So that the auxiliary frame 160 can be fixedly mounted on the cover plate 150. The side wall 164 is bent upward in the vertical direction at the outer end of the horizontal portion 162, The pallet 10 serves to prevent the load on the pallet 10 from being separated from the pallet 10 and serve as a box pallet.

7 (b), a bent portion 165 is formed at an end portion of the horizontal portion 162 of the auxiliary frame 160 and an upper end portion of the side wall 164 to bend inward, The rigidity of the auxiliary frame 160 can be improved and the ends of the auxiliary frame 160 can be rounded to prevent damage to the operator or load caused by the sharpness of the auxiliary frame 160 .

One or more forceps 164a may be formed on the side wall 164 of the auxiliary frame 160. The force of the forceps 164a may be increased by increasing the structural rigidity of the side wall 164, And to minimize the deformation.

8 (b), the horizontal portion 162 and the side wall 164 are formed in a double-layered structure as shown in FIG. 8 (b) As shown in FIG.

That is, the structural rigidity of the auxiliary frame 160 can be improved by forming the horizontal part 162 and the side wall 164 constituting the auxiliary frame 160 in a double structure.

At this time, the space 166 may be formed on the inner side of the side wall 164. In this case, the space 166 absorbs the impact applied from the outside.

9 (a), in the case of the side wall 164 having the second space 166 formed therein as described above, one or more force portions 166a for improving the structural rigidity are provided in the second It may be formed so as to protrude toward the inside or outside of the space portion 166.

9B, the side wall 164 of the auxiliary frame 160 is tilted outward, that is, the angle formed by the horizontal surface 162 and the side wall 164 is an obtuse angle, more preferably, 100 ° to 135 °. This is because the upper plate 100 to which the auxiliary frame 160 is coupled can also be stacked, thereby reducing the volume occupied during transportation.

In order to prevent unnecessary waste of material, the auxiliary frame 160 is formed to have a closed shape of 'ㅁ' shape by bending a single plate, wherein the plate has two layers, that is, (164) and a horizontal portion (162) are formed, and both end portions thereof are bent at the upper end of the side wall (164) and fastened to each other.

That is, as shown in FIG. 8 (b), the structural rigidity of the side wall 164 is improved by forming a reinforcing portion 168 that is bent and joined to the upper end of the side wall 164 so that both side ends of the plate are engaged with each other So that it is possible to prevent injury to the operator or damage to the load due to the sharpness of the end of the plate.

When the auxiliary frame 160 is formed by bending one plate as described above, a cutout 162a is formed at four corners of the horizontal portion 162 so that the corner portions do not overlap with neighboring faces have.

In this case, although not shown, four corners of the horizontal portion 162 may be overlapped by bending without forming the cut-out portion 162a.

The auxiliary frame 160 may be coupled to the upper portion of the cover plate 150 by various methods such as welding or fastening by bolts or the like and may be attached to the outer frame 110 The auxiliary frame 160 may be provided directly on the upper surface.

The upper plate 100, the lower plate 200, and the support member 300, which constitute the pallet 10 by using a pipe or rod-like frame or members, can be used as the pallet 10 according to the present invention, So that the support force can be enhanced while minimizing the weight of the pallet 10 and the upper plate 100, the lower plate 200 and the support member 300 can be respectively transported so that they can be assembled and used immediately in the field, It is possible to innovatively reduce the transportation cost by minimizing the volume of the lower plate 100, the lower plate 200, and the support member 300. By rounding all the parts forming the outer rim, it is possible to reduce the worker's injury due to the sharpness of the rim, The auxiliary frame 160 is provided on the upper part of the upper plate 100 to prevent the loaded products from being separated from the upper plate 100. In addition, And can be selectively assembled and used with a lattice.

Although the preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention.

10: pallet 100: top plate
110, 210: an outer frame 120, 220:
130, 230: longitudinal member 140: horizontal frame
150: cover plate 160: auxiliary frame
162: horizontal portion 162a: incision groove
164: side wall 164a:
165: bending section 166:
168: reinforcement part 200: lower plate
212: coupling groove 300: support member
310: first coupling portion 312, 322: first cover
312a, 322a: first through hole 312b, 322b: first inclined surface
312c, 322c: engagement jaws 312d, 322d: bolt insertion holes
314, 324: second cover 314a, 324a: second through hole
314b, 324b: second inclined surfaces 314c, 324c:
314d, 324d: wedge portion 316, 326: fixing member
316a and 326a: through holes 316b and 326b: teeth
330: support rod 332: fastening groove

Claims

In the prefabricated steel pallet,
An upper frame and a lower frame including a frame member having a plurality of coupling grooves formed on an upper surface or a lower surface thereof and a plurality of transverse members and a longitudinal member provided so as to cross each other on the inner side of the frame,
And a support member in the form of a round bar which is connected between the upper and lower plates to form an engagement groove formed in an outer frame of the lower plate to support the upper plate.

The method according to claim 1,
Wherein the outer frame, the horizontal member and the vertical member are made of a square pipe.

The method according to claim 1,
The support member includes first and second engaging portions respectively inserted into the engaging grooves formed in the outer frames of the upper and lower plates and a support bar connected between the first and second engaging portions. Prefabricated steel pallet.

The method of claim 3,
Wherein the first and second engagement portions comprise a first lid configured to enclose an end portion of the support rod, a second lid coupled to the inside of the first lid, and a second lid provided between the first lid and the second lid, And a fixing member for guiding the pallet.

5. The method of claim 4,
Wherein the fixing member is formed with a through hole having a sawtooth circumferential shape, and both side ends of the support bar are formed with coupling grooves engaged with the through holes.

5. The method of claim 4,
The first lid and the second lid are provided with first and second through holes through which the support rods are inserted. The first lid and the second lid have a first inclined surface and a second inclined surface, And a groove is formed in the end of the first inclined surface so as to protrude therefrom and an end of the second inclined surface is formed with an engagement groove in which the latching jaw is engaged.

The method according to claim 1,
Wherein a plurality of horizontal frames are provided between the outer frame and the vertical member of the upper plate and between the vertical member and the vertical member.

The method according to claim 1,
And a cover plate installed on the upper portion of the upper plate.

9. The method of claim 8,
Wherein an auxiliary frame having a cross section of '?' Shape including a horizontal part and a side wall is installed on the upper edge of the cover plate.

10. The method of claim 9,
And the angle between the horizontal portion and the side wall is an obtuse angle.

10. The method of claim 9,
Wherein a bent portion bent inward is formed at the end portion of the horizontal portion and the side wall, and at least one cutout portion is formed in the side wall.

10. The method of claim 9,
Wherein the horizontal portion and the side wall are formed in two layers, and a space portion is formed inside the side wall.

10. The method of claim 9,
Wherein the auxiliary frame is formed in a double structure by bending a single plate, and a reinforcing portion is formed at an upper end of the side wall so that both side ends of the plate are bent so as to be engaged with each other.