Foundation block for guardrail

Abstract

To bend a connecting part of a connecting recessed part and a connecting projecting part in a base block of a type for fitting the connecting projecting part of a trapezoidal shape in a plan view into the connecting recessed part of a Ali groove shape.SOLUTION: The foundation block for the guardrail is provided with a long body part, a dovetail groove-shaped connection recessed part vertically formed at one end of the body part, and a connection projecting part formed at the other end side of the body part and having a trapezoidal shape in plan view to be fitted to the dovetail groove of the connection recessed part, and at least one of a first wall surface corresponding to the bottom wall of the dovetail groove in the coupling recess and a second wall surface facing the first wall surface of the coupling recess in the coupling protrusion has a mountain shape with a central portion as a vertex, and a gap is formed in the width direction except for the central portion between the first wall surface and the second wall surface in a state where the central portion of the second wall surface is in contact with the first wall surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a foundation block for a guardrail. [Background technology]

[0002] Conventionally, guardrail foundation blocks (hereinafter simply referred to as "foundation blocks") have been installed on roads by connecting male and female metal connecting members protruding from both ends of a long concrete body. To ensure the safety of pedestrians and others, even when an external force is applied to the foundation block due to a vehicle collision, the connecting parts are prevented from coming loose, and the bending angle at the connecting parts (the angle formed by the connected connecting members) is limited. Having metal connecting members protruding from both ends of the concrete body made manufacturing the foundation blocks time-consuming and hindered efforts to reduce manufacturing costs.The metal connecting parts also caused problems when transporting the foundation blocks.

[0003] Therefore, it has been considered to form male and female connecting parts integrally, i.e., made of concrete, on both ends of the main body. For example, in the foundation block described in Patent Document 1, as shown in Figure 1 and paragraph 0045, it is proposed to form a dovetail-shaped connecting recess 4 on one end of the main body and a trapezoidal connecting protrusion 3 on the other end. In addition, please also refer to Patent Publication 2 and Patent Publication 3 related to the present invention. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6842523 [Patent Document 2] Patent No. 3188436 [Patent Document 3] Japanese Utility Model Application Publication No. 6-57918 Summary of the Invention [Problem to be solved by the invention]

[0005] In the foundation block disclosed in Patent Document 1, the connecting protrusion is fitted into the dovetail-shaped connecting recess, and the undercut of the dovetail prevents the foundation block from coming loose in the axial direction, but it is difficult to bend the connected foundation block at the connecting point between the two. When installing foundation blocks, the next foundation block is placed axially adjacent to the previously installed foundation block, so the connecting recess and connecting protrusion abut on their opposing axial surfaces. If the connecting recess is a typical dovetail groove, the first wall surface, which corresponds to its bottom wall, is flat, and the second wall surface of the connecting protrusion facing this first wall surface is also flat. When the flat first and second wall surfaces abut, it becomes difficult to bend the foundation block horizontally at the connection point between the connecting recess and connecting protrusion. [Means for solving the problem]

[0006] The present invention has been made to solve such problems, and its first aspect is defined as follows: A concrete foundation block for a guardrail includes a main body, a dovetail-shaped connecting recess formed perpendicularly at one end of the main body, and a trapezoidal connecting protrusion formed at the other end of the main body and fitted into the dovetail groove of the connecting recess, A foundation block for guardrails, wherein at least one of a first wall surface corresponding to the bottom wall of the dovetail groove in the connecting recess and a second wall surface facing the first wall surface of the dovetail groove in the connecting protrusion has a mountain shape in a plan view with a central point as an apex, and when the central point of the second wall surface is abutted against the first wall surface, a gap is formed in the width direction between the first wall surface and the second wall surface excluding the central point.

[0007] According to the foundation block of the first aspect defined above, the connecting portions formed on the main body are integral with the main body, i.e., the main body, connecting recesses, and connecting protrusions are integrated into the concrete, thereby reducing manufacturing and transportation costs. Furthermore, because the main body portions are connected to each other by the dovetail-shaped connecting recesses and connecting protrusions, the undercut of the dovetail groove prevents the foundation blocks from slipping out in the alignment direction, i.e., in the axial direction of the main body portions.

[0008] Furthermore, when the foundation blocks are installed close together in the axial direction, the relationship between the opposing surfaces of the connecting recess and the connecting protrusion is such that the centers of the first wall surface of the connecting recess and the second wall surface of the connecting protrusion abut. This is because at least one of the first wall surface and the second wall surface is formed in a mountain shape in a plan view with the center as the apex. In addition, a gap is formed in the width direction between the first wall surface and the second wall surface, excluding the center, so that only this center abuts and the other surfaces are separated. This allows the foundation block to rotate horizontally around the abutting part. In other words, the foundation block can bend at the connection part between the connecting recess and the connecting protrusion.

[0009] In a second aspect of the present invention, in the foundation block as defined in the first aspect, a first wall surface of the connecting recess corresponding to a bottom wall of the dovetail groove is formed flat; In the connecting protrusion, the second wall surface facing the first wall surface of the dovetail groove is a mountain-shaped surface that slopes outward in the width direction from the center and away from the first wall surface, and when the center of the second wall surface is abutted against the first wall surface, a widthwise gap is formed between the first wall surface and the second wall surface, excluding the center portion.

[0010] In the base block of the second aspect defined above, the first wall surface is flat, which makes it easy to form. In other words, the wall surface of the dovetail-shaped first recess is formed by a core, but because the first wall surface is flat, high precision is not required in the design of the core. The second wall surface is made into a mountain shape that slopes from the center outward in the width direction away from the first wall surface because the second wall surface of the connecting protrusion is formed by the end plate, and making this surface an inclined surface improves the releasability of the end plate. The foundation blocks defined in the second aspect as defined above are not subjected to loads during the manufacturing process, and can therefore be provided at low cost.

[0011] A third aspect of the present invention is defined as follows. In the foundation block defined in the first aspect, when the connecting protrusion is fitted into the connecting recess and the center of the second wall surface of the connecting protrusion is abutted against the first wall surface of the connecting recess, the other wall surface of the connecting recess and the other wall surface of the connecting protrusion are spaced apart. According to the base block of the third aspect defined in this way, the connecting recess and the connecting protrusion are in a loose fit state, so that the bending of the connecting portion between them is smooth. Furthermore, it not only becomes easier to fit the connecting protrusions into the connecting recesses, but also makes it easier to remove the foundation blocks when they are damaged by external impact and need to be replaced.

[0012] A fourth aspect of the present invention is defined as follows: In the foundation block defined in the third aspect, the width of the connecting protrusion and the width of the connecting recess are smaller than the width of the main body, a first shoulder is provided at one end of the main body so as to sandwich the connecting recess, and a second shoulder is provided at the other end of the main body so as to sandwich the connecting protrusion, When a change occurs in the connection angle between the first main body portion and the second main body portion at the connection portion between the connecting recess of the first main body portion and the connecting protrusion of the second main body portion, the first shoulder portion and the second shoulder portion interfere with each other preferentially, thereby determining the connection angle.

[0013] According to the foundation block of the fourth aspect, when the first body portion and the second body portion are bent at the connection portion between the connecting recess and the connecting protrusion, the first shoulder portion and the second shoulder portion interfere with each other preferentially. In other words, strong contact between the connecting recess and the connecting protrusion is suppressed, and external impact forces are supported solely by the first shoulder portion of the first body portion and the second shoulder portion of the second body portion. It goes without saying that the first and second shoulder portions are stronger than the connecting recess and the connecting protrusion. Therefore, the foundation block of the fourth aspect has excellent impact resistance.

[0014] The fifth aspect of the present invention is defined as follows: In the foundation block defined in the second aspect, the second shoulder portion continuous with the engaging protrusion is inclined from the base of the engaging protrusion toward the center of the main body portion with respect to the imaginary cross-section of the main body portion. The second shoulder portion is also formed by the end plate of the mold, and by inclining the second shoulder portion, the mold releasability of the end plate is improved.

[0015] The sixth aspect of the present invention is defined as follows: In a fifth aspect, a groove communicating in the width direction is formed on the bottom surface of the main body portion. The side plates that form the foundation block can be connected to each other with metal rods or the like through these communicating grooves. This allows the side plates to be connected to each other simply and stably, making it easier to manufacture the foundation block. The grooves also function as drainage channels.

[0016] The seventh aspect of the present invention is defined as follows: In the foundation block of the second aspect, reinforcing steel bars are embedded in the connecting protrusions, and the reinforcing steel bars extend from the connecting protrusions to the main body portion. According to the foundation block of the seventh aspect defined in this way, the connecting protrusions are reinforced with reinforcing bars, thereby improving impact resistance.

[0017] The eighth aspect of the present invention is defined as follows: In the base block of the third aspect, the upper edge of the engagement recess is formed into a tapered surface that is cut out to widen upward. According to the foundation block of the eighth aspect defined in this manner, the upper edge of the engaging recess is made into an upwardly widening tapered surface, so that when the engaging protrusion is fitted into the engaging recess, this tapered surface guides the lower surface of the engaging protrusion, making it easier to fit the two together. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view showing a conventional foundation block. [Figure 2] FIG. 2 is a plan view of a foundation block according to an embodiment of the present invention. [Figure 3] FIG. 3 is a front view of the same. [Figure 4] FIG. 4 is a longitudinal sectional view of the same. [Figure 5] FIG. 5 is a cross-sectional view showing the installation of the foundation blocks. [Figure 6] FIG. 6 is an enlarged view of the connecting portion between the connecting recess and the connecting protrusion. [Figure 7] Figure 7 shows an example of how external forces are applied to foundation blocks. [Figure 8] FIG. 8 is a plan view showing the bending state at the connection portion. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a plan view of the base block 1 of the embodiment, FIG. 3 is a front view, and FIG. 4 is a vertical cross-sectional view. This foundation block 1 is an integrally molded concrete product comprising a main body 10, a connecting recess 20 and a connecting protrusion 50. Three holes 11 are formed on the top surface of the main body 10, and poles such as guardrails to be installed on the foundation block 1 are inserted into these holes 11. The number and diameter of the holes 11 can be set as desired. In order to support one unit of guardrail, the main body 10 is required to have a certain length, which can be, for example, 400 to 2000 mm.

[0020] A groove 12 is formed in the underside of the main body 10, penetrating in the width direction. A connecting rod (not shown) is passed through this groove 12 to connect the side plates of the mold that forms the side walls of the main body 10. This prevents deformation of the side plates when the mold is filled with concrete material. It is preferable that this groove 12 be formed symmetrically around the center of the underside of the main body 10 so as not to interfere with the hole 11.

[0021] In the main body 10, a connecting recess 20 is formed in the center of the right end in the illustration, and a connecting protrusion 50 is formed in the center of the left end in the illustration. The connecting recess 20 and the connecting protrusion 50 are narrower than the main body 10, and first shoulders 15, 15 are formed on either side of the connecting recess 20 at the right end of the main body 10, with the corners of the first shoulders 15, 15 cut off and forming curved surfaces 16, 16 facing upward.

[0022] The upper edge of the connecting recess 20 is formed as a tapered surface 23 that is cut so as to open upward. Second shoulder portions 17, 17 are formed on the left end of the main body portion 10 so as to sandwich the connecting protrusion 50, and the corners thereof are cut to form curved surfaces 18, 18 facing upward. Reinforcement can be achieved by embedding reinforcing bars in the connecting protrusions 50 and reaching the main body 10.

[0023] As shown in Figure 5, the connecting recess 20 and the connecting protrusion 50 are connected by inserting the connecting protrusion 50 at the left end of the second main body part 10-2 from above into the connecting recess 20 at the right end of the first main body part 10-1 installed on the road.

[0024] FIG. 6 shows a plan view of the connecting recess 20 and the connecting protrusion 50 in a connected state. The first wall surface 21 of the connecting recess 20 that faces the connecting protrusion 50 is a flat surface, and the second wall surface 51 of the connecting protrusion 50 that faces the first wall surface 21 is mountain-shaped in plan view with a central portion 53 as its apex. In other words, an inclined surface 55 is formed around the central portion 53 of the second wall surface 51, and as the inclined surface 55 moves away from the central portion 53 outward in the width direction, it moves away from the flat first wall surface 21. As a result, even when the first wall surface 21 and the second wall surface 53 are in contact with each other, a gap is formed between the first wall surface 21 and the inclined surface 53. As a result, the connecting recess 20 and the connecting protrusion 50 can bend in the horizontal direction around the central portion 53 of the connecting protrusion 50 that is in contact with the first wall surface 21 of the connecting recess 20.

[0025] Such an effect can also be achieved by making the second wall surface flat and employing a first wall surface that is shaped like a mountain in plan view, with the portion of the first wall surface 21 that abuts against the center of the second wall surface being the apex. Both the first wall surface and the second wall surface may have the above-described mountain shape in plan view.

[0026] Such second wall surface 51 is formed by the end plate when the foundation block 1 is manufactured, and therefore, by forming such an inclined surface 55, the end plate can be easily removed from the mold. Similarly, since the second shoulder portions 17, 17 formed to sandwich the connecting protrusion 50 are also formed by end plates, it is preferable that the second shoulder portions 17, 17 also have inclined surfaces in the same direction as the inclined surface 55. The inclination angles of the inclined surface 55 and the second shoulder portions 17, 17 can be made the same.

[0027] Here, in the connecting recess 20 and the connecting protrusion 50, the wall surfaces other than the first wall surface 21 and the second wall surface 51 are also separated from each other to form a gap therebetween, and the connecting recess 20 and the connecting protrusion 50 are in a loose fit state, which makes the connecting operation shown in Figure 4 easy.

[0028] In Figure 5, when the first main body part 10-1 has already been installed on the road, when the second main body part 10-2 is to be added, the second main body part 10-2 is pushed toward the first main body part 10-1, in other words, pressed against it, so that the connecting protrusion 50 of the second main body part 10-2 fits into the connecting recess 20 of the first main body part 10-1. At this time, since the tapered surface 23 is formed on the upper edge of the connecting recess 20 , this tapered surface 23 guides the lower edge of the connecting protrusion 50 , allowing the connecting protrusion 50 to drop smoothly into the connecting recess 20 .

[0029] At this time, as shown in Figure 6, there is a gap between the first wall surface 21 and the second wall surface 51, and the other wall surfaces are also spaced apart from each other, so that the first main body portion 10-1 and the second main body portion 10-2 can be easily bent at the connection portion between the connecting recess 20 and the connecting protrusion 50.

[0030] FIG. 7 shows the impact of a vehicle V against a series of foundation blocks. When an external force is applied as shown in FIG. 7, the first body portion 10-1 and the second body portion 10-2 bend as shown in FIG. In the base block 1 of the embodiment, when bending occurs at the connecting portion between the connecting recess 20 and the connecting protrusion 50, as can be seen in Figure 7, the first shoulder 15 and the second shoulder 17 of the main body 10 interfere with each other preferentially, restricting bending beyond a predetermined angle. Here, the interference between the shoulders reduces interference between the peripheral walls of the continuous recess 20 and the continuous protrusion 50. It is also understood that the gap between the first wall surface 21 and the second wall surface 51 acts effectively in the initial refraction of the connecting portion (in the range where the refraction angle is small).

[0031] Although the embodiments and modifications of the present invention have been described in detail above, the present invention is not limited to these descriptions in any way. [Explanation of symbols]

[0032] 1 foundation block 10 Main body 12 grooves 15, 15 1st shoulder 17, 17 2nd shoulder 20 Connection recess 21 First Wall 50 Connecting protrusion 51 Second wall

Claims

1. A concrete foundation block for a guardrail includes a main body, a dovetail-shaped connecting recess formed perpendicularly at one end of the main body, and a trapezoidal connecting protrusion formed at the other end of the main body and fitted into the dovetail groove of the connecting recess, At least one of the first wall surface corresponding to the bottom wall of the dovetail groove in the connecting recess and the second wall surface facing the first wall surface of the dovetail groove in the connecting protrusion is mountain-shaped with its apex at the center, and when the center of the second wall surface is abutted against the first wall surface, a gap is formed in the width direction between the first wall surface and the second wall surface excluding the center.

2. a first wall surface of the connecting recess corresponding to a bottom wall of the dovetail groove is formed flat; The foundation block of claim 1, wherein in the connecting protrusion, the second wall surface facing the first wall surface of the dovetail groove is a mountain-shaped surface that slopes outward in the width direction from the center and away from the first wall surface, and when the center of the second wall surface is abutted against the first wall surface, a widthwise gap is formed between the first wall surface and the second wall surface except for the center portion.

3. A foundation block as described in claim 2, wherein when the connecting protrusion is fitted into the connecting recess and the center of the second wall surface of the connecting protrusion is abutted against the first wall surface of the connecting recess, the other wall surface of the connecting recess and the other wall surface of the connecting protrusion are spaced apart.

4. a width of the connecting protrusion and a width of the connecting recess are smaller than a width of the main body, a first shoulder is provided at one end of the main body so as to sandwich the connecting recess, and a second shoulder is provided at the other end of the main body so as to sandwich the connecting protrusion, A foundation block as described in claim 3, wherein when a change occurs in the connection angle between the first main body portion and the second main body portion at the engagement portion between the connection recess of the first main body portion and the connection protrusion of the second main body portion, the first shoulder portion and the second shoulder portion interfere preferentially and determine the connection angle.

5. The foundation block according to claim 2, wherein a second shoulder portion continuous with the engaging protrusion is inclined from the base of the engaging protrusion toward the center of the main body portion with respect to the imaginary cross-sectional plane of the main body portion.

6. The foundation block according to claim 5, wherein a groove communicating in the width direction is formed on the bottom surface of the main body portion.

7. 3. The foundation block according to claim 2, wherein reinforcing steel bars are embedded in the connecting protrusions, and the reinforcing steel bars extend from the connecting protrusions to the main body portion.

8. 4. The foundation block according to claim 3, wherein the upper edge of the engagement recess is a tapered surface that is cut out to widen upward.

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