JP2002327487A - Concrete side ditch lid, and side ditch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure related to a concrete side ditch lid creating no rattling sound or other noises even though there are errors in shape between a side ditch lid receiving edge and the bottom surface of a lid plate which guarantees the flatness for the lid surface in the case where many side ditches continue along roads. SOLUTION: A lid plate shape is supported at three points. This concrete side ditch lid has a trapezoidal shape akin to a triangle in a plan view which substantially realizes a support by three points. Also, a structure having a header surface as a sloped side of the lid plate being a twisted surface is adopted. Further, the header surface forming a trapezoidal oblique side is a twisted surface having tilt angles opposite to each other. When a lid plate having header surfaces having tilt directions of both the twisted ends being opposite to each other is placed on the side ditch by butting the header surfaces, one of the adjacent lid plates restricts the upper motion of the other, and the other restricts the upper motion of the former. Thus, a phenomenon of the removal or jumping up of one of the lid plates can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a concrete cover plate of a gutter provided on a road, a parking lot or other premises, and a shape error exists between a receiving edge of the gutter block and a lower surface of the cover plate. The present invention relates to a structure of a concrete gutter which is free from rattling and noise of the gutter.

[0002]

2. Description of the Related Art A gutter cover used by being placed on a gutter block such as a U-shaped gutter block or a variable gradient block is bent,
In addition to having the basic strength to withstand external force loads such as shearing, the flatness of the lid plate surface when placed on the gutter block and the wheel load traveling on the lid plate Can be installed so as to prevent the occurrence of the problem, and can be maintained.

The gutter lid is generally preferred to be square in view of the effective use of its surface and the ease of manufacture, and the bearings are provided at four places near the corners. On the other hand, there is a principle that three points form one surface in the law of geometry. That means that it is extremely difficult, if not impossible, for the four fulcrums to form exactly the same plane. Therefore, the four fulcrum points of the gutter lid normally formed form a total of two surfaces, one for each of two common points and another one. It is practically impossible to form the same two planes at the four points on the lid plate side and the four points on the gutter block side, including the formation of these two surfaces on the same plane on both the lid plate side and the gutter block side. It is.
In other words, the lid plate supported by four fulcrums originally has the fate of being a matter of course.

[0004] Even more problematic is that the amount of play increases over time. Now, the four-point bearing is filled with a wedge or the like to fill the gap created under one fulcrum by the sliding method,
Even if a perfect four-point support state can be achieved, if a slight gap is subsequently formed at any of those fulcrums, the load on the vehicle running on the lid generally acts intermittently, so loading and unloading may occur. The hitting operation is repeated on the fulcrum. At this time, the amount of play increases due to the impact destruction of the fulcrum, and the inconvenience also increases.

[0005] On the other hand, there is another method in which the cover plate and the bearing portion of the side groove block are completely brought into close contact with each other so as to prevent play. It is a V-shape formed by folding one of the part in contact with the lower surface bearing of the lid plate and the bearing receiving part into a part of two cylindrical surfaces and the other into a plane on a certain straight line on the plane. Is a part of the bent surface of Two of these cylindrical surfaces are
The fact that each of the bent surfaces is always in linear contact with each other will be described with reference to FIGS. In the figure, reference numeral 17 denotes a bent surface obtained by folding a plane by an intentional straight line 40 on the surface to form an inverted V-shape. Now this V-shaped one side to 41 and 42,
When two cylinders 43 and 44 are arranged and contacted one by one as shown in the figure, the respective contact portions are in contact with the cylindrical surface and the flat surface, so that two thin linear shapes 45 and 46 are formed. But,
The two cylinders 43 and 44 can relatively freely and abut on any position. This is because the cylinders 43 and 44
This means that they can be arranged in a wide range of free relative relationships with respect to the parallelism, the crossing angle, and the distance between the axes of the thin lines with the other cylinders. Now, as shown in FIG. 18, both cylindrical surfaces near the contact line 46 are formed as two bearing portions at the lower end of one lid plate, and receive the contact lines 45 and 46 near the bent surfaces 41 and 42 with the cylindrical surface. When they are used as bearing surfaces, the two are linear, but they can be completely in close contact with each other without any play. At this time, the difference in the diameters of the two cylinders has no effect, and it is only necessary to make a straight line contact with the opposite plane. Therefore, there is no problem even if the cylindrical surface is a conical surface having different diameters at both ends. .

In the above description, two cylinders are arranged outside the inverted V-shape as the bent surfaces 41 and 42. However, as shown in FIG. 19, two planes are formed in a V-shape on the contrary. The same applies when a cylinder is attached inside the cylinder. This indicates that the bearing surface and its receiving bearing surface are the same even if they are interchanged.

[0007] The above description has long been known to those skilled in the art of carpenters that "a mountain-shaped roof can be placed in close contact with two log beams, and if the log beams are straight, the diameters at both ends are different. However, the two lines need not be parallel. "

[0008]

The method of supporting the lid plate by applying the two flat surfaces and the two cylindrical surfaces can surely ensure a tight fit, but has the following three disadvantages. I do.

First, the contact support surface is linear. This is because the bearing area due to the contact between the cylindrical surface and the flat surface is as close to zero as possible, and the bearing stress obtained by dividing the force to be supported by the area is large and theoretically indicates infinity. Therefore, the state shifts from elastic deformation of the contact portion to plastic contact and flow deformation to surface contact due to crushing failure of the contact portion. As the surface contact progresses, it becomes closer to the four-point support, which leads to the fate of the four-point support.

The second problem is that there is a mutual positional relationship in which the two sets of the flat surface and the cylindrical surface are in close contact at the same time, but it is not obtained at the first time, and then automatically enters that state. Not even a thing. It is necessary to try the combination by shifting the contact portion artificially to find a mutual positional relationship without play. When the lid plate is heavy, the operation is difficult and time-consuming.

The third disadvantage is that although this method has a playless combination, it has nothing to do with the configuration of the lid surface flatness. That is not taken into account. It is also evident from the fact that the trial of the combination of the lid and the lid receiver itself, which is the second of the above drawbacks, induces disturbance of the flatness of the lid surface. Reveals that nothing has been done. In conclusion, this method without three-point support is suitable for the installation of only one set of cover plates, but is not suitable for the configuration of the flatness of the surface of the combination of many continuous cover plates such as road gutters. Has doubts.

Further, in terms of manufacturing, it is added that there are difficulties in the exact configuration of the two cylindrical surfaces.

[0013]

According to the present invention, the cover plate has a shape of four.
One fulcrum is deleted from the fulcrum, and three points are supported.
This is an ideal structure in which three fulcrums always form one surface, so that there is no backlash against the load. That is, the concrete gutter according to the present invention has a trapezoidal shape which is substantially triangular in plan view and which realizes substantially three-point support.

There is no problem with the above-mentioned structure in which the gutter cover is supported at three points. The fact that the number of fulcrums is three means that if the cover plate is provided with a protruding portion such as a cantilever, the cover plate may be provided. In this case, the planar shape of the cover plate is a triangle or a trapezoid close to it. Now, trapezoids are also included in triangles, and these will be referred to as approximate triangles. The determination of the shape of the approximate triangle largely depends on the determination of the side length of the lid plate having three fulcrums and three sides.

FIG. 14 is a schematic plan view of an ordinary rectangular lid plate, and it is assumed that the dimension of the side in the groove width direction is W and the dimension L of the side in the groove length direction is also close to W. FIGS. 15 and 16 are schematic plan views of approximate triangles. When the groove width is constant as in the case of the side groove cover, the side length is minimum when the side is perpendicular to the direction perpendicular to the center line P of the groove, but when the cover plate is an approximate triangle, the groove width direction is inevitable. At least one of the two sides 28 is an inclined side that intersects with the center line P of the groove at an angle other than a right angle,
It is always longer than the right-angled side. At this time, if the area of the cover plate is to be increased, at least one of the three types of sides must be lengthened, which is disadvantageous in strength.
Now, in FIG. 16, if the narrow angle α formed by the sides 28, 28 in the groove width direction is a right angle, the side length is the same as the area of the square lid plate of W, but the maximum length at that time is The side L is approximately twice the right side W, and the inclined side is also 1.414 times. In order not to make one of the three sides of the triangle extremely long, FIG.
It is preferable to make the three sides substantially equal and to make the shape of the cover plate a shape close to an equilateral triangle. At this time, the three sides are almost the same length, which is approximately 1.155 times W, and the area of one lid is approximately 0.577 times the square lid plate having one side W. Therefore,
A lid plate having three sides which is advantageous in strength and has three sides is inevitably smaller in area, that is, lighter than a rectangular lid plate having the same groove width.

It is considered that when the lid plate is lightweight, vertical movement easily occurs due to wheel load. In fact, a grating that is lighter than a concrete lid plate tends to move up and down when the vehicle runs. However, it is considered that this is often caused by backlash of the bearing portion and restoration of elastic deformation.
That is, when the vehicle travels at high speed on a cover plate with a backlash on the support portion, the cover plate swings according to the movement of the load point on the cover plate, and if the swing is rapid, the cover plate will move up and down. Occurs. In addition, the metal grating is bent by a load, and causes vertical movement when the bent is rapidly restored. The concrete three-point support lid plate does not cause vertical movement due to such a situation.

The light weight of the lid plate has an advantage that the lid can be easily opened and closed. On the other hand, this advantage also has a disadvantage that the lid plate is easily removed due to mischief or the like. In addition, it is certain that if it is lightweight, it can be easily moved by the same external force. Due to the nature of the lid plate, it is often desired to give the lid plate some degree of difficulty in moving (moving).

In such a case, a structure in which a fore-edge surface serving as an inclined side of the lid plate is a twisted surface is employed. That is, the gutter according to the invention of claim 2 of this application is characterized in that the fore-edge surface forming the trapezoidal oblique side is a twisted surface in which the inclination angles are opposite at both ends.

Normally, the fore-edge surface and side surfaces 24 and 25 of the cover plate are perpendicular to the surface of the cover, and the side surfaces 24 and 25 of the cover plate and the parapet wall 5 are connected to each other so that the cover can be easily mounted or removed. Since there is a gap between the gaps and between the fore-faces of the lid plate, there is no frictional resistance there, and there is no action to suppress the vertical movement of the lid plate. On the other hand, in the case of a lid plate with a small torsion surface, the inclination direction of the small surface as viewed from the side at the torsion end is opposite, so that the upward movement of the adjacent lid plate is prevented at one torsion end. At the twisted end on the other side, there is an effect that the upward movement of the self is suppressed by the adjacent lid plate. That is, when a lid plate provided with a fore surface having a twisted surface in which the two twisted ends have opposite inclination surfaces is placed on the side groove with the fore surface abutted, one of the adjacent lid plates is placed on the other. The effect is obtained that the movement is suppressed and the other part suppresses the upward movement. For this reason, it is possible to prevent a phenomenon that one of the cover plates comes off or jumps up.

The gutter of the present invention is constructed by closing the opening on the upper surface of the gutter block with the gutter lid having the above structure. The gutter having a preferred structure has a plurality of gutter lids each having one or more isosceles trapezoidal lids and a single trapezoidal lid disposed at both ends thereof in a plan view. It is a structure that is closed with sheets.

Another preferred structure of the gutter is a lid plate in which a pair of two side gutter lids each having a trapezoidal shape in a plan view are formed such that the openings of the gutter blocks abut each other with the inclined small edge surfaces to form a rectangle. The structure is closed by groups.

More preferably, in the side groove of the above structure, a metal spacer elongated in the groove width direction is inserted between the connecting small beam of the side groove cover and the side groove block or the adjacent side groove cover. This is a structure using a spacer having a water hole.

[0023]

1 to 5 show a first embodiment of the present invention. FIG. 1 is a plan view of a gutter block provided with a set of several cover plates, and FIG. FIG. 3 is a side sectional view showing a cross section of the side groove block in the vicinity of an upper portion of the side groove. The gutter block 1 according to the first embodiment is a variable slope block, and as a gutter cover, an equilateral trapezoidal cover plate 2 close to an equilateral triangle shown in FIG. 4 and a one-side trapezoidal cover plate 2a shown in FIG.
And are used. The isosceles trapezoidal lids 2 are arranged with short sides 21 and long sides 22 alternately, and one trapezoidal lids 2a are arranged at both ends of a set of lid plates.

The receiving edge 3 of the cover plates 2 and 2a is located at the upper edge of the side wall 4 of the side groove block, and a parapet wall 5 for protecting the cover plate and securing its position is provided upright outside the receiving edge. The receiving edges 3 on both sides are formed in a single plane as in the case of a conventional general side groove block, but errors in the height direction (surface undulations) inevitably exist. At both longitudinal ends of the upper surface of the side groove block, connecting small burrs 6 for connecting the parapet walls 5 on both sides are provided. When the side groove length L is large, the connecting small burrs 6 may be provided at positions other than both ends. A rectangular opening is formed inside the opposing burrs and the opposing parapet wall therebetween. All four sides around this opening are perpendicular to the lid surface 23.

In this opening, an equal leg trapezoidal lid 2 and a single trapezoidal lid 2a
Are inserted as a set. If the side surfaces 24, 25 and the fore-edge surfaces 26, 27 of each cover plate are perpendicular to the cover surface 23, each cover plate is vertically placed from top to bottom. And the lid can be easily removed by pulling it up in the vertical direction.

In the first embodiment, in order to suppress the individual vertical movement of each lid plate, the trapezoidal lid 2 and the one-sided lid 2a
As shown in FIG. 4 and FIG. 5, the inclined small edge surfaces 26 and 26a are twisted surfaces. The fore-edge surface 27 perpendicular to the side surface of the single trapezoidal lid 2 a is a plane perpendicular to the lid surface 23.
The side surfaces 24, 25 and 24a, 25a forming the top and bottom sides of both trapezoidal lids are planes perpendicular to the lid upper surface.

One of the four corners of the twisted fore-face 26 in FIG. 4 is denoted by A, B, b, a, and the other four corners are denoted by d, c, C, D. The plane 24 on the short side of the two parallel sides of the trapezoid is a,
In planes b, C, and d, the long side plane 25 is indicated by A, B, C, and D. The line connecting ab, cd, AB, and CD is
All are straight lines. The inclination directions of the straight lines ab and AB are opposite and the inclination angles are the same, and the straight lines cd and C
The direction of inclination of -D is opposite and the inclination angle is the same. Further, the straight lines ab and DC are parallel, and the straight lines dc and AB are parallel. That is, the plane on the parapet wall 5 side is trapezoidal, and 2
The two trapezoids abcd and ABCD are both isosceles trapezoids, and their up and down directions are opposite. The fore-edge surface 26 is a twisted surface, but the lines Aa, Bb, cC, and dD are all straight lines.

The fore-edge surface 26 referred to as the above-mentioned torsion surface is a higher-order curved surface, and it is thought that it is difficult to form the surface, but the shape of the molding surface of the mold is extremely simple. As one forming method, a rectangular metal plate abBA which can be easily twisted and deformed but is strong in tension is prepared, and twisted while being pulled in a direction opposite to the ab side and the BA side. If the iron plate is fixed to the straight side aA and the straight side bB by setting the inclination of ab and the inclination of BA to the same amount and in opposite directions, a formed surface of the twisted surface abBA can be obtained.

There is also another method of forming a twisted formed surface by cutting without using the metal sheet. Now, a narrow cutting tool is moved along the straight line ab from the inside of the surface 26 to cut out the thin ab surface, and then on the straight lines aA and bB of the same length toward the end points A and B at minute equal intervals. If the cutting is continued, the female mold having the twisted molding surface can be cut out.

Usually, the side gutter is made of reinforced concrete from the viewpoint of easiness of manufacture and economy, and is formed by a metal mold. What is necessary is just to incorporate the member.

In the one-sided lid plate 2a shown in FIG. 5, only the fore-edge surface 26a on the side of the inclined side is a twisted surface having the same shape as the fore-edge surface 26 of the lid plate in FIG. When the cover plates 2 and 2a having such a twisted small surface are fitted into the opening of the side groove block 1, as shown in FIG. 3, the contact surfaces between the adjacent cover plates are closer to the near side (solid line) and the inner side. The side (dotted line) presses the fore-edge surfaces of the adjacent lid plates together, thereby preventing the lid plates from being individually lifted or removed.

If the length of the lid plate and the length of the opening are set so that an appropriate play space is formed in the fore-edge direction (groove length direction) of the plurality of placed lid plates, the end lid plate 2a Connecting small burr 6
By lifting up to rotate from the side, the lid plate at the end can be opened. Then, if the lid plate at the end is removed, the remaining lid plate can be removed by slightly shifting it in the groove length direction to separate the fore-edge surfaces from each other. The mounting of the lid plate may be performed in the reverse order.

When it is desired to more firmly suppress the removal and upward movement of the cover plate, as shown in FIGS. 7 and 8, after the cover plate 2a at the end is mounted, the space between the cover plate and the connecting small beam 6 is formed. Spacers 7 are inserted to bring the fore-edge surfaces of the lid plates 2 and 2a into close contact with each other.
In this state, the rotation of the end cover plate is also prevented, so that the plurality of cover plates are fixed as if they were a single cover plate. If the spacer 7 is removed and the cover plate is appropriately shifted using the open space, a desired cover plate can be removed. If the spacer 7 is practically made of metal and has a structure having a water passage hole 71 such as a narrow grating, it is easy to remove the spacer 7 by inserting a hook into the water passage hole and pulling it up. It is.

When providing such a spacer, FIG.
As shown in FIG. 5, a single trapezoidal lid 2a that forms a rectangle
It is also possible to close the opening of the gutter block only by using only the opening.
In the example of FIG. 9, the opening of the side groove block 1 is closed by two sets of rectangles formed by two pieces of the single trapezoidal lid 2 a, and the spacer 7 is inserted into the two rectangular connection parts. The trapezoidal lid 2a is shown in FIG.
The inclined small surface 26a shown in FIG.
5 and 27 are plane blocks perpendicular to the lid surface. As described above, if the fore-edge surfaces of the lid plates are brought into close contact with each other with the spacer 7, the upward movement and removal of the lid plate having only one fore-edge surface as a twist surface can be reliably prevented.

The inclined small face of the lid plate shown in FIGS. 4 and 5 is a twisted face whose inclination angle changes continuously.
As shown in FIG. 1, it is also possible to use a twisted surface in which the inclination angle changes stepwise (in the example in the figure, in one step), and in this case, the vertical movement of the individual lid plates described above also The effect of being suppressed by the twist surface is exerted without any difference. In the examples of FIGS. 10 and 11, the inclination angles of the inclined small faces 26, 26a are changed at once in the opposite direction at the center in the width direction of the lid plates 2, 2a, and both sides of the change point (the top side and the bottom side of the trapezoid). The inclination angle is set to be a constant inclination plane. That is, the torsion surfaces 26 and 26a of each lid plate are formed by two inclined planes having opposite inclination angles. FIG.
In FIGS. 4 and 5, the top and bottom sides of the trapezoid are shown in FIGS.
And the tilt angle are in the opposite direction. In terms of the degree of bending stress when a wheel load is applied, the direction of the inclination angle shown in FIGS. 10 and 11 is advantageous.

The side groove block is connected to the upper surface without small burrs.
In the case of a grooved block, a set of a plurality of the above-described isosceles trapezoidal lids and one-sided trapezoidal lids at both ends thereof can be sequentially arranged, or as shown in FIG. Can also be arranged. However, in this case, the lid plate 2b in which one of the fore-edge surfaces 26b of the inclined fore-edge side is a plane perpendicular to the surface.
Must be provided at appropriate intervals, otherwise the operation when it is necessary to remove one or a part of the cover plate becomes impossible. Therefore, considering the versatility, the combination of the isosceles trapezoidal lid 2 and the single trapezoidal lid 2a shown in FIG. 4, 5 or FIGS. It is practical to use a rectangular unit formed by combining two lids 2a as one unit.

If the connecting small burrs 6 provided at both longitudinal ends of the upper surface of the gradient side groove block are formed in a trapezoidal shape as shown in FIG. 12 and the opening is formed as a long and slender rhombus, the U shown in FIG. This opening can be closed by two types of trapezoidal lids 2 and 2b for the groove. In this case, the cover plate 2b having one inclined small edge surface 26b as a plane perpendicular to the surface becomes the cover plate at both ends of the opening adjacent to the small beam. When the opening is a distorted rhombus, the lid plates 2b at both ends may be the same, but when the opening is trapezoidal, the directions of the small opening surfaces 26b at right angles to the surfaces of the lid plates 2b at both ends are opposite. , Three types of lid plates are required.

When the gutter with the cover plate mounted thereon is completed as described above, the portion where the torsion surfaces abut on one cover plate and the upper side of the edge surface of the adjacent cover plate protrudes, The lids are placed on the portions projecting below the one lid plate, and they interfere with each other, so that the lid plates cannot be individually pulled up. This relationship is the same when the lid vibrates or shakes due to a vehicle load on the lid plate, and one or more adjacent lid plates correspond to those movements, and the three-point support lid plate has The disadvantages derived from light weight are eliminated.

Next, a structure for more reliably assuring three-point support of the lid plate without play will be described. Note that the three points referred to here are not points in a geometric sense, but actually are surfaces each having a certain area. The size of this surface is naturally determined by the strength of the contact stress on the concrete surface. When the moment acting on the bearing point due to the external force exceeds the moment due to the weight of the lid plate, the lid plate rattles, so even if the lid plate and its bearing edge have a finite area. If the area is sufficiently small, or if one bearing is actually composed of a plurality of points, but the distance between the points is sufficiently small, three such bearing points are required.
The lid plate supported by the individual may be regarded as a three-point support from the viewpoint of preventing backlash.

First, with respect to the four lid plates, three support points on one parapet wall 5 side are at the lower portion on the bottom side 22 side of the trapezoidal lid plate. As shown in FIG. 6, the seats 31 and 32 having small areas near the points B and C provided on the lower surfaces at both ends of the bottom are the same. It is important for the seats 31 and 32 to hold two points at both ends of the base that are surely separated from each other. Cause all ye. Therefore, in the lid plate of the embodiment shown in the figure, the lid thickness of the portions of the seats 31 and 32 is larger than the lid thickness of the portion other than the bearing point by a minute thickness Δt.
The remaining one support point 33 on the lid side is located at the top side opposite to the bottom side, and the lid thickness at this portion is the same as the lid thickness at the seats 31 and 32. .

The parapet wall 5 regulates the movement of the cover plate on the receiving edge 3 in the groove width direction or the rotation thereof.
No matter how high the flatness inside the parapet wall is, if the bottom side of the lid side in contact with it is a continuous plane,
This makes the entire surface contact, and the production accuracy of the lid plate must be increased. Therefore, in the lid plate of the illustrated embodiment, the bottom is receded inward by a small width that does not allow the heel of the shoe to enter, so that only the both ends of the bottom side surface 25 come into contact with the parapet wall 5.

It is necessary that the rainfall near the road is caused to quickly flow down into the installed gutters and not to stay on the road surface. Otherwise, they wet the feet of pedestrians on sidewalks and cause splashing or hydroplane phenomena on pedestrians on roadways. For this reason, metal gratings and the like are used to drop rainwater from the gutters, but it is extremely expensive and sometimes slippery, and heels of shoes into slits for dropping water. There is no danger of intrusion. Also, since the shape of the grating is generally a quadrilateral, once rattling occurs, it emits an unpleasant high metal sound due to the vehicle load passing over it,
In addition, since it is made of a metal having high elasticity, it is easy for a jump to occur, and it is difficult to prevent such a jump.

The gap between the shallow recess 34 provided on the bottom side of the cover plate of this embodiment and the receiving edge formed between the seats 31 and 32 at both ends on the lower surface of the cover plate 2 is equal to that of the cover plate 2. Since the slit-shaped water supply is formed between the gutter and the side gutter block, the surface water on the road can be quickly guided into the gutter.

[0044]

Since the gutter cover of the present invention has the above-mentioned structure, it does not peel off as a gutter cover plate, and the flatness of the upper surface of the gutter where the gutter plate is installed is also maintained well. There is no step between the cover plates and between the cover plate and the connecting small burr of the side groove block. Further, the plurality of lid plates that have the twisted fore-faces in contact with each other are constrained to each other so that their attachment and detachment and upward movement are performed integrally.
Whether the twisted fore-face is provided on both sides or only on one side,
By arranging the number of lid plates that are adjacent to each other and twisted in the case of being provided on both sides, the area of the lid that is quasi-integrated and therefore the weight of the lid can be easily opened and closed, It can be selected as appropriate in consideration of regulations and jumps, for example, the side grooves of the sidewalk are easy to open, and the side grooves of the roadway adopt an arrangement structure where the movement of each lid plate is more strongly regulated, Design and construction according to the place of use is possible.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment.

FIG. 2 is a cross-sectional view of the gutter of FIG. 1;

FIG. 3 is a longitudinal sectional view of the gutter of FIG. 1;

FIG. 4 is a perspective view of an equipod trapezoidal lid according to the first embodiment.

FIG. 5 is a perspective view of a single trapezoidal lid according to the first embodiment.

FIG. 6 is a perspective view showing the lower surface of the isosceles trapezoidal lid of FIG. 4;

FIG. 7 is a plan view of a side groove according to the second embodiment.

FIG. 8 is a perspective view of a spacer.

FIG. 9 is a plan view of a gutter according to a third embodiment.

FIG. 10 is a perspective view showing another embodiment of an isosceles trapezoidal lid.

FIG. 11 is a perspective view showing another embodiment of a single trapezoidal lid.

FIG. 12 is a plan view of a gutter according to a fourth embodiment.

FIG. 13 is a plan view of a gutter according to a fifth embodiment.

FIG. 14 is a plan view of a rectangular lid.

FIG. 15 is an explanatory view of a preferable three-point supporting gutter.

FIG. 16 is an explanatory view of another gutter lid supported at three points.

FIG. 17 is an explanatory view of a roof support structure using logs.

FIG. 18 is a cross-sectional view of a conventional side groove.

FIG. 19 is an explanatory view showing the principle of the conventional structure of FIG. 18 in relation to FIG. 17;

[Explanation of symbols]

 1 Side groove block 2, 2a, 2b Side groove cover 3 Receiving edge 7 Spacer 26, 26a Twisted small surface 27, 27b Small surface orthogonal to lid surface

Claims (5)

[Claims] 1. A concrete side gutter having a trapezoidal shape that is substantially triangular in plan view and that substantially realizes three-point support. 2. The concrete gutter according to claim 1, wherein the fore-edge surface forming the trapezoidal hypotenuse is a twisted surface having opposite inclination angles at both ends. 3. A set of one or a plurality of isosceles trapezoidal lids having an opening of the side groove block in a plan view and is disposed at both ends thereof. A gutter closed by a plurality of the described gutter lids. 4. A lid plate group comprising a pair of gutter lids according to claim 1 or 2, wherein the opening of the gutter block has a single trapezoidal shape in a plan view in which a rectangular shape is formed by abutting small inclined surfaces. The gutter is closed at. 5. The side groove according to claim 3, wherein an elongated metal spacer is inserted in the groove width direction between the side groove cover and the connecting small beam of the side groove block or an adjacent side groove cover.