KR102301214B1 - Grating with Embossed Structure - Google Patents

Abstract

Disclosed is a grating having an embossed structure which prevents slipping and can withstand high loads. According to the present invention, by forming a first anti-slip protrusion including a hole therein and a second anti-slip protrusion in the form of embossing on the periphery of an opening to prevent slipping, the grating can prevent slipping around the opening when rain or snow enters through the opening. In addition, by firmly fixing a reinforcing unit supporting an upper plate to the grating through welding after intersecting and combining a main reinforcing rib and an auxiliary reinforcing rib, it is possible to prevent the grating from twisting or sagging even when a high load such as a vehicle is applied.

Description

Grating with Embossed Structure

The present invention relates to a grating having an embossed structure, and more particularly, to a grating having an embossed structure capable of preventing slippage and withstanding a high load.

In general, gratings are installed and used on both sides of the road or in drainage channels in areas with a lot of pedestrians, such as schools, parks, and apartments. It performs the function of the blocking structure to prevent it at the same time.

1 is a view showing a conventional grating.

Referring to FIG. 1, the general structure of the grating consists of an end bar 11 made of flat iron as in FIG. 1 in a standard square shape, and a plurality of bearing bars 12 between the end bars 11, etc. The grating is installed at an interval, and a drain hole 14 is formed between the bearing bar 12 and the cross bar 13 by welding a cross bar 13 that supports the bearing bar 12 and maintains the distance therebetween. (10) constitutes.

The grating 10 of the above configuration performs the function of covering and draining the drain and preventing the inflow of relatively large foreign substances. However, since the conventional grating 10 is fixed by welding a plurality of bearing bars 12 and cross bars 13, the strength to withstand a large load is low, and thus durability is weak. That is, the conventional grating 10 is twisted or sagged when a high load, such as a vehicle, is applied. Therefore, a lot of cost is incurred in maintenance, and the damaged grating 10 also causes a risk to the passage of pedestrians or vehicles.

In addition, since the upper surface of the conventional grating has a structure in which a lattice form consisting of only bearing bars and crossbars is exposed, pedestrians or vehicles slip and fall on the upper surface of the grating when it rains or there is water, causing injuries or colliding with other vehicles. Serious problems that frequently occur in safety accidents exist.

Korea Registered Patent 10-2068687

The technical problem to be achieved by the present invention is to provide a grating having an embossing structure that is not deformed even under a high load by a vehicle, etc., and can prevent pedestrians or vehicles from sliding when it is raining or wet.

The grating having the embossed structure of the present invention for solving the above problems is formed with a number part having a flange that is bent downward and extends, and an upper plate having an anti-slip means formed to protrude from the upper surface, both ends of the upper plate in the width direction A pair of first side plates that are bent downward and extend, a pair of second side plates that are bent downwardly extending from both ends in the longitudinal direction of the upper plate, and a reinforcing unit provided under the upper plate to support the upper plate Including, the anti-slip means is formed in a portion in contact with the reinforcing unit and the upper plate.

A plurality of the number parts are formed to have predetermined intervals in the longitudinal direction and the width direction of the upper plate, and a first repair hole having a first interval and a second interval in the length direction and a size smaller than the first number hole, , may include a second hole formed on the first interval.

The first interval may have a larger interval than the second interval.

The reinforcing unit may include a main reinforcing rib having a thickness equal to that of the second interval, a main reinforcing rib disposed in the second interval, and an auxiliary reinforcing rib having a thickness smaller than that of the main reinforcing rib and intersecting the main reinforcing rib. can

a first coupling groove formed on the main reinforcing rib and a second coupling groove formed on the auxiliary reinforcing rib; can be combined.

The reinforcing unit may be coupled through welding such that both ends of the main reinforcing rib are in contact with the first side plate and both ends of the auxiliary reinforcing rib are in contact with the second side plate.

The anti-slip means is formed on the first gap and the second gap, and is formed on the first gap and the second gap and a first anti-skid protrusion having a through-hole so that water flows into the protruding inside. However, it may include a second non-slip protrusion having a higher height and a narrower radius than the first non-slip protrusion.

The second non-slip protrusion may have an embossing shape.

A diameter of the second non-slip protrusion may have the same size as the second interval.

The second non-slip protrusion may be formed adjacent to the second opening hole.

The anti-slip means may be formed by pressing in an outward direction from the inner portion of the upper plate.

According to the present invention, by forming a first anti-slip protrusion including a hole therein and a second anti-slip protrusion in the form of embossing on the periphery of the water receiving portion for anti-slip, sliding around the water port when rainwater or snow flows in through the water port can prevent the

In addition, by forming the anti-slip protrusion having an embossed shape to be disposed on the reinforcing unit and the flange, it has an effect that the anti-slip protrusion is not deformed even under a high load as well as an anti-slip effect.

In addition, it is possible to simplify the process and reduce manufacturing costs by not including a separate structure to prevent slipping, and by forming non-slip protrusions through burring or forming processing on the upper plate.

Furthermore, the reinforcing unit supporting the top plate crosses the main reinforcing rib and the auxiliary reinforcing rib with each other and then firmly fixes the grating to the grating through welding to prevent the grating from twisting or sagging even when a high load such as a vehicle is applied. can

The technical effects of the present invention are not limited to those mentioned above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a view showing a conventional grating.
2 is a perspective view of the grating of the present invention viewed from the top.
3 is a perspective view of the grating of the present invention viewed from the lower side.
Figure 4 is a view showing the coupling form of the reinforcing rib of the present invention.
5 to 7 are views showing a method of manufacturing a grating according to an embodiment of the present invention.

Since the present invention can apply various transformations and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. do it with

Example

2 is a perspective view of the grating of the present invention viewed from the top.

3 is a perspective view of the grating of the present invention viewed from the lower side.

2 and 3 , the grating 100 according to the present invention includes a top plate 110 , a pair of first side plates 120 , a pair of second side plates 130 , and a reinforcing unit 140 . include The pair of first side plates 120 and the pair of second side plates 130 are respectively bent from the top plate 110 to be integrally formed. The upper plate 110 is provided with a water-receiving part 111 and an anti-slip means 112 , and a flange 113 is extended to the lower side of the upper plate 110 around the water-receiving part 111 . A first protrusion 131 is formed at both ends of the second side plate 130 , respectively, and a first hole 121 into which the first protrusion 131 is inserted is formed in the first side plate 120 .

The configuration of the grating 100 according to an embodiment of the present invention will be described in detail as follows.

The upper plate 110 has a rectangular shape as a whole, and a plurality of opening portions 111 are formed therein. The pair of first side plates 120 are respectively bent downward from opposite ends in the width direction of the upper plate 110 and extend, and the pair of second side plates 130 are both ends of the upper plate 110 in the longitudinal direction, respectively. Doedoe bent downward in the extension, the first side plate 120 and the second side plate 130 are integrally formed with the upper plate (110). The first side plate 120 and the second side plate 130 are seated on the drain pipe to support the upper plate 110 . At this time, it is preferable that the first side plate 120 and the second side plate 130 are formed at the same height so that the grating 100 is not inclined.

The first side plate 120 and the second side plate 130 have an upper plate 110 positioned at the center of one metal plate, and a pair of first side plates 120 are positioned on both sides of the upper plate 110, respectively, It can be formed by bending the first side plate 120 and the second side plate 130 to the lower side of the top plate 110 in a state where a pair of second side plates 130 are respectively located at the top and bottom of the top plate 110 . have.

In order for the first side plate 120 and the second side plate 130 to stably support the top plate 110 , both ends of the first side plate 120 and the second side plate 130 are preferably fixed to each other.

In order to fix both ends of the first side plate 120 and the second side plate 130 to each other, a first protrusion 131 is formed on any one of the first side plate 120 and the second side plate 130 , and the other A first hole 121 into which the first protrusion 131 is inserted is formed. In this embodiment, it is illustrated that the first protrusion 131 is formed on the second side plate 130 and the first hole 121 is formed on the first side plate 120 . . When the first side plate 120 and the second side plate 130 are bent downward with respect to the top plate 110 , the first protrusion 131 is inserted into the first hole 121 , and is inserted into the first hole 121 . The tip of the first protrusion 131 may be bent, twisted, or caulked to prevent the first protrusion 131 from falling out again from the first hole 121 . In addition, welding or the like may be used to firmly fix both ends of the first side plate 120 and the second side plate 130 .

The number part 111 is formed to penetrate from the upper surface to the lower surface of the upper plate 110 , and a plurality of parts are formed to form a predetermined pattern. The opening part 111 has an elliptical shape, and a flange 113 bent downward is formed around the opening part 111 . The flange 113 extends a predetermined distance from the lower surface of the upper plate 110 . Rainwater or snow may be introduced through the opening part 111 . The opening part 111 is preferably formed in a curved shape as in the present embodiment in order to reduce stress concentration that may be generated during machining of the flange 113 . However, the shape of the number part 111 is not limited to the structure shown in the present embodiment, and may be changed to various structures such as a circle, a rectangle, and a polygon.

In addition, the repair part 111 according to the present invention may include a first repair hole 114 and a second repair hole 115 .

A plurality of first openings 114 are formed at predetermined intervals in the longitudinal and width directions of the upper plate 110 , and the first openings 114 formed in the longitudinal direction are formed at a first interval D1 and a second interval ( D2) may be formed in multiple numbers. Here, the first gap D1 may have a wider width than the second gap D2 .

The second opening 115 may have a smaller size than the first opening 114 . A plurality of second openings 115 may also be formed in the longitudinal direction and the width direction of the upper plate 110 . However, the second opening 115 may be formed between the first opening 114 and the first opening 114 to be disposed on the first gap D1 of the first opening 114 . can

That is, by additionally forming a second opening 115 having a smaller size than the first opening 114 between the first opening 114 and the first opening 114, it is further attached to the top plate 110 of the grating. It is possible to form a large number of the number of parts (111). In addition, by forming the second opening 115 smaller than the first opening 114 , stress concentrated in the opening 111 may be dispersed. Therefore, many water openings 111 are formed on the top plate 110 of the grating 100 so that rainwater flows smoothly, but it is possible to prevent deformation even under a high load.

The flange 113 is bent downward from the circumference of the opening part 111 to extend. The flange 113 prevents the water receiver 111 from sagging or deforms due to the load in the vertical direction acting on the water receiver 111, and at the same time guides the flow of rainwater flowing through the water receiver 111. Allow rainwater to flow smoothly. The flange 113 may be formed in both the first opening 114 and the second opening 115 .

In general, when a through-hole is simply formed in a structure, stress concentration occurs around the through-hole, and thus it has a disadvantage in that it is structurally weak. However, in the grating 100 according to the present invention, the flange 113 is formed on the periphery of the receiving part 111 despite the plurality of receiving parts 111 being formed on the upper plate 110, so that the receiving part 111 part Since stress concentration does not occur, the total weight of the grating 100 can be reduced and has the effect of supporting the load without being deformed even under a high load. In addition, since the area of the water receiving part 111 is formed to be larger than the area of the upper plate 110 of the grating 100 , there is an effect that the drainage capacity is improved.

The reinforcing unit 140 is a long plate-shaped member and is provided under the upper plate 110 to support the upper plate 110 . The upper surface of the reinforcing unit 140 is connected to the lower surface of the upper plate 110 , and both ends of the reinforcing unit 140 are fixed to the first side plate 120 or the second side plate 130 , respectively. Reinforcing units 140 may be provided in plurality, and in this case, they are disposed to be spaced apart from each other in the longitudinal direction or the width direction of the upper plate 110 . The reinforcing unit 140 supports the upper plate 110 so that the upper plate 110 is not sagged or deformed by a load applied in the vertical direction to the upper plate 110 .

For example, the reinforcing rib 140 is disposed along the longitudinal direction of the top plate 110 so that both ends are fixed to the first side plate 120 , or both ends are fixed to the first side plate 120 and the second side plate 130 . They may be disposed at the same time to form a lattice shape by being orthogonal to each other along the length direction and the width direction as much as possible. Hereinafter, an example in which both ends of the reinforcing unit 140 are fixed to the first side plate 120 and the second side plate 130 to be orthogonal to each other will be described.

As shown in FIG. 3 , the reinforcement unit 140 according to the present invention includes a main reinforcing rib 141 spaced apart from each other in the longitudinal direction of the upper plate 110 and an auxiliary spaced apart from each other in the width direction of the upper plate 110 . Reinforcing ribs 142 may be included.

The main reinforcing ribs 141 may be disposed to be spaced apart from each other in the longitudinal direction of the upper plate 110 , and both ends may be disposed to be fixed in contact with the first side plate 120 . In addition, the plurality of main reinforcing ribs 141 may be respectively disposed between the first opening 114 and the first opening 114 . In more detail, the main reinforcing rib 141 may be formed to have the same thickness as the second gap D2 of the first opening 114, and the upper surface is in contact with the lower portion of the upper plate 110, and both sides are It may be disposed so as to be in contact with the outer circumferential surface of the flange 113 formed by the first opening 114 . That is, by disposing both sides of the main reinforcing rib 141 to be in contact with the outer surface of the flange 113 of the first opening hole 114 so that the main reinforcing rib 141 is constrained by the flange 113 , the main reinforcing rib Since the 141 is prevented from flowing in the lateral direction, the main reinforcing rib 141 can be more stably fixed to the grating 100 .

The auxiliary reinforcing ribs 142 may be disposed to be spaced apart from each other in the width direction of the upper plate 110 , and may be disposed to cross the main reinforcing ribs 141 .

The thickness of the auxiliary reinforcing rib 142 may be the same as the thickness of the main reinforcing rib 141 or may be formed to have a smaller thickness. In addition, the height of the auxiliary reinforcing rib 142 is preferably formed to have a height equal to or less than the height of the main reinforcing rib 141 .

This is because the auxiliary reinforcing rib 142 serves to assist the main reinforcing rib 141 to be mounted more firmly to prevent lateral flow, so that it has a smaller thickness and height than the main reinforcing rib 141 This is because it is desirable to reduce the cost of materials by forming.

Figure 4 is a view showing the coupling form of the reinforcing rib of the present invention.

Referring to FIG. 4 , the main reinforcing rib 141 and the auxiliary reinforcing rib 142 may include a first coupling groove 143 and a second coupling groove 144 , respectively. That is, the main reinforcing rib 141 in which the first coupling groove 143 is formed may be coupled to the auxiliary reinforcing rib 142 in which the second coupling groove 144 is formed to be fixed to the upper plate 110 .

As an example, the first coupling groove 143 may be formed as many as the number of auxiliary reinforcing ribs 142 are mounted, and the second coupling groove 144 may be formed as much as the number of the main reinforcing ribs 141 are mounted. . That is, the main reinforcing rib 141 and the auxiliary reinforcing rib 142 may be coupled by inserting the first coupling groove 143 and the second coupling groove 144 to cross each other.

After coupling the auxiliary reinforcing rib 142 on the main reinforcing rib 141 , the reinforcing unit 140 has both ends of the main reinforcing rib 141 in contact with the first side plate 120 , and the auxiliary reinforcing rib 142 . Both ends may be firmly fixed using welding so that they are in contact with the second side plate 130 .

Continuingly, referring to FIG. 2 , the top plate 110 may include an anti-slip means 112 . The anti-slip means 112 is formed to prevent safety accidents, such as when it rains or there is water on the grating 100, when a pedestrian or a vehicle slips and falls on the upper surface of the grating and is injured or collides with another vehicle. In addition, the anti-slip means 112 is formed to protrude upward from the upper plate 110 in the remaining portion of the upper plate 110 in which the number part 111 is not formed, the first non-slip protrusion 116 and the second It may include an anti-slip protrusion 117 .

The first anti-skid protrusions 116 may be formed to be spaced apart from each other by a predetermined interval on the upper part and the lower part of the receiving part 111 . In addition, the first non-slip protrusion 116 is formed to protrude upwardly around the circular hole, and a through hole 118 is formed in the center of the first non-slip protrusion 116 so that water can be introduced into the protruding inside. can be The first non-slip protrusion 116 has a periphery of the through hole 118 protruding upward to further increase the frictional force, so that even if water is stagnant or snow accumulates on the top plate 110 of the grating 100, pedestrians or vehicles do not slip. is prevented In addition, since rainwater or snow around the first non-slip protrusion 116 can be introduced through the through hole 118 of the first non-slip protrusion 116, the friction force of the upper plate 110 can be reliably secured. .

The second non-slip protrusion 117 may have a higher height than the first non-slip protrusion 116 , and may have a smaller radius than the first non-slip protrusion 116 . Accordingly, a greater number than the first non-slip protrusion 116 may be formed on the top plate 110 . In addition, the second non-slip protrusion 117 may be formed to have a hemispherical shape of an embossed shape protruding upward from the top plate 110 . However, the shape of the second non-slip protrusion 117 may be changed to various structures such as a square, a triangle, and a polygon.

The second non-slip protrusion 117 may be formed on the first gap D1 and the second gap D2 of the first opening 114 . Therefore, the size of the second non-slip protrusion 117 is preferably formed to have the same size as the first gap (D1). Here, the second non-slip protrusion 117 formed on the second gap D2 may be located on the main reinforcing rib 141 . That is, by forming the second anti-skid protrusion 117 to be supported by the main reinforcing rib 141 constrained by the flange 113, the second anti-skid protrusion 117 and the first The number of holes 114 may have an effect that is not deformed.

In addition, the second anti-skid protrusions 117 formed on the first gap D1 may be respectively formed to be adjacent to the upper and lower portions of the second opening 115 . That is, by forming the second non-slip protrusion 117 to be adjacent to the first opening 114 and the second opening 115 , when rainwater or snow flows in through the opening 111 , the water receiving unit 111 . ) has the effect of preventing the surrounding slippery.

Such a non-slip means 112 may be formed through a burring process or a forming process on the upper plate 110 . Therefore, since a separate structure is not added to prevent slipping, it is possible to simplify the process and reduce costs.

As described above, the grating 100 according to the present invention has a first non-slip protrusion 116, a first repair hole 114, and a second repair hole 115 formed on the upper and lower portions of the first repair hole 114. Through the second non-slip protrusion 117 formed to be adjacent to the rain, it is possible to prevent a pedestrian or a vehicle from slipping when there is water or rain.

5 to 7 are views showing a method of manufacturing a grating according to an embodiment of the present invention.

5 to 7, the manufacturing method of the grating according to the present invention is a piercing process step of forming various holes including burring holes 210 and 220 in the prepared metal plate 200, burring holes 210, 220 by processing the flange A burring process step of forming 113, a forming process step of forming the anti-slip means 112 on the metal plate 200, a bending process step of bending the first side plate 120 and the second side plate 130, and a coupling step of fixing the reinforcing unit 140 to the metal plate 200 .

First, in the piercing process step, as shown in FIG. 5 , burring holes 210 and 220 are formed in the flat metal plate 200 . The metal plate 200 is a flat panel made of metal in which the upper plate 110 , the first side plate 120 , and the second side plate 130 are formed on the same plane. Here, the burring holes 210 and 220 are formed to pass through the metal plate 200 , and may include a first burring hole 210 and a second burring hole 220 . For example, the first burring hole 210 may be a hole for forming the first opening 114 , and the second burring hole 220 may be a hole for forming the second opening 115 . Accordingly, the first burring hole 210 may have the burring holes 210 and 220 having a size larger than that of the second burring hole 220 . At this time, the metal plate 200 may be formed with a through hole 118 for forming the first non-slip protrusion 116 .

Next, a burring process step is performed on the metal plate 200 on which the piercing process step is performed. As shown in FIG. 6 , in the burring process step, the first burring hole 210 and the second burring hole 220 formed in the piercing process step are expanded and the first opening 114 and the second opening hole ( 115 , the flange 113 is formed around the first opening 114 and the second opening 115 at the same time. Burring is performed by inserting a burring punch or a press punch having a cross-sectional area larger than the area of the hole into the burring holes 210 and 220 formed in the metal plate 200 to expand the burring holes 210 and 220. Or it is a processing method of forming the flange 113 around the burring holes (210, 220).

A forming process step of forming the non-slip means 112 for the metal plate 200 on which the burring process step is performed is performed. The anti-slip means 112 is formed between the first opening 114 and the first opening 114, and the first non-slip protrusion 116 is inside the grating 100 at the hole position formed in the piercing process step. It may be formed by pressing the part outward. In addition, the second anti-skid protrusion 117 is formed between the flange 113 and the flange 113 formed by the first opening 114 , on the upper and lower sides of the flange 113 formed by the second opening 115 . can be formed in each. The second non-slip protrusion 117 may be formed in an embossed form by pressing the corresponding position outward from the inner portion of the grating 100 . As an example, the anti-skid means 112 may be formed through burring or forming so that the first anti-slip protrusion 116 and the second anti-slip protrusion 117 protrude in the upper direction of the metal plate 200 . . Therefore, since a separate structure is not added to prevent slipping, there is an effect of simplifying the process and reducing the manufacturing cost.

After the anti-slip means 112 is formed on the metal plate 200 , as shown in FIG. 7 , the first side plate 120 and the second side plate 130 are bent with respect to the upper plate 110 . In the bending process step, the first side plate 120 and the second side plate 130 are bent downward with respect to the top plate 110 along the bending line 201 . At this time, in the bending process of the first side plate 120 and the second side plate 130 , the first protrusion 131 can be inserted into the first hole 121 without a separate additional process, the first side plate 120 and Among the second side plates 130 , the ones in which the first protrusions 131 are formed are first bent, and then the ones in which the first holes 121 are formed are later bent. In other words, in the present embodiment, the second side plate 130 on which the first protrusion 131 is formed is first bent, and then the first side plate 120 with the first hole 121 is bent by bending the first side plate 120 during the bending process step. The first protrusion 131 is automatically inserted into the first hole 121 .

When the bending process is completed, the reinforcing unit 140 is fixed to the metal plate 200 . In the step of fixing the reinforcing unit 140 to the metal plate 200 , the reinforcing unit 140 may further include a coupling step of coupling the main reinforcing rib 141 and the auxiliary reinforcing rib 142 . That is, by inserting the first coupling groove 143 formed in the main reinforcing rib 141 and the second coupling groove 144 of the auxiliary reinforcing rib 142 to cross each other, the main reinforcing rib 141 and the auxiliary reinforcing rib 142 ) can be combined. After the coupling of the reinforcing unit 140 is completed, the upper end of the reinforcing unit 140 is in contact with the upper plate 110 , both ends of the main reinforcing rib 141 are on the first side plate 120 , and the auxiliary reinforcing rib 142 . Both ends of the second side plate 130 may be firmly fixed using welding.

As described above, the grating 100 having an embossed structure according to the present invention includes a first non-slip protrusion 116 including a hole therein and a second non-slip protrusion 117 in the embossed form to prevent slipping. By forming in the periphery of the part 111, it is possible to prevent slippage around the water receiving unit 111 when rainwater or snow flows in through the water receiving unit 111, and the anti-slip means 112 having an embossed shape is provided as a reinforcement unit. By forming it to be disposed on the 140 and the flange 113, it has an effect that the anti-slip means 112 is not deformed even under a high load as well as an anti-slip effect. In addition, it is possible to simplify the process and reduce manufacturing costs by forming the anti-slip means 112 on the top plate 110 through burring or forming without including a separate structure to prevent slipping. Furthermore, the reinforcing unit 140 supporting the upper plate 110 crosses the main reinforcing rib 141 and the auxiliary reinforcing rib 142 with each other and then firmly fixes to the grating 100 through welding, thereby forming a vehicle and Even when the same high load is applied, it is possible to prevent the grating 100 from being twisted or sagged.

On the other hand, the embodiments of the present invention disclosed in the present specification and drawings are merely presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. It will be apparent to those of ordinary skill in the art to which the present invention pertains that other modifications based on the technical spirit of the present invention can be implemented in addition to the embodiments disclosed herein.

110: top plate 111: repair part
112: anti-slip means 113: flange
114: first repair hole 115: second repair hole
116: first non-slip protrusion 117: second non-slip protrusion
118: through hole 120: first side plate
121: first hole 130: second side plate
131: first projection 140: reinforcement unit
141: main reinforcement rib 142: secondary reinforcement rib

Claims (11)

an upper plate having an anti-slip means formed to protrude from the upper surface, the upper plate is formed with a receiving portion having a flange that is bent downwardly extending;
a pair of first side plates bent downward from both ends of the upper plate in the width direction and extending;
a pair of second side plates bent downward from both ends of the upper plate in the longitudinal direction; and
and a reinforcing unit provided under the upper plate to support the upper plate,
The number part,
a plurality of first hole holes formed to have a predetermined interval in the longitudinal direction and the width direction of the upper plate, the first opening having a first interval in the longitudinal direction and a second interval narrower than the first interval; and a second opening having a size smaller than that of the first opening and formed on the first interval,
The reinforcement unit is
a main reinforcing rib having the same thickness as the second gap and disposed in the second gap; and an auxiliary reinforcing rib having a thickness smaller than that of the main reinforcing rib and formed to intersect the main reinforcing rib,
The anti-slip means is formed by pressing in an outward direction from the inner portion of the upper plate,
a first non-slip protrusion formed on the first gap and the second gap and having a through hole through which water flows into the protruding inside; and a second non-slip protrusion formed on the first gap and the second gap, and an embossed second anti-skid protrusion having a higher height and a narrower radius than the first anti-slip protrusion,
The second non-slip protrusion is formed to be adjacent to a portion in which the main reinforcing rib and the upper plate contact and the second opening hole,
The second non-slip protrusion is formed in a portion of the main reinforcing rib and the upper plate in contact with the grating having an embossed structure, wherein the main reinforcing rib is formed in a portion of the upper plate in contact with the flange. delete delete delete According to claim 1,
a first coupling groove formed on the main reinforcing rib; and
and a second coupling groove formed on the auxiliary reinforcing rib;
A grating having an embossed structure for coupling the main reinforcing rib and the auxiliary reinforcing rib by inserting the second coupling groove into the first coupling groove. According to claim 1, wherein the reinforcing unit,
Both ends of the main reinforcing rib are in contact with the first side plate, and both ends of the auxiliary reinforcing rib are coupled through welding so that they are in contact with the second side plate. delete delete delete delete delete

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