Guard fence, cross beam for guard fence, connecting structure of cross beam for guard fence

Abstract

To provide a protective fence capable of preventing a vehicle from breaking into a lane under construction even when unexpected collision energy is applied.SOLUTION: In a protective fence, a base end part 34 having a width that is narrower than a cross beam 3a, a first male fitting part 41 having a width that is wider than the base end part 34, a protrusion part 42 having a width that is narrower than the first male fitting part 41, and a second male fitting part 43 having a width that is wider than the protrusion part 42 and narrower than the first male fitting part 41 are provided in order on one end side of the cross beam 3a from the base end to the tip thereof, an opening 50 through which the base end part 34 is guided and can be inserted, a first female recess part 51 having a width that is wider than the opening 50, into which the first male fitting part 41 can be fitted, an insertion part 52 having a width that is narrower than the first female recess part 51, through which the protrusion part 42 can be inserted, and a second female recess part 53 having a width that is wider than the insertion part 52 and narrower than the first female recess part 51, into which the second male fitting part 43 can be fitted are provided in order on the other end side of the cross beam 3a from the base end to the tip thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a safety fence having multiple levels of cross beams attached to posts, a cross beam for a safety fence that is installed on at least the top level of the posts of the safety fence, and a method for connecting them. [Background technology]

[0002] Conventionally, when carrying out work such as repairing or replacing deck slabs on a bridge, it is common to leave only some of the multiple lanes open for vehicle traffic, while carrying out work on the other lanes. In such cases, it is common to temporarily install protective fences at the boundary between the travel lane and the lane under construction to prevent vehicles traveling on the travel lane from deviating and entering the other lane under construction (see, for example, Patent Document 1).

[0003] Conventional temporary guardrails have been proposed that are made of elastic materials to absorb collisions with vehicles and minimize damage while ensuring the safety of occupants. Among these guardrails, some have been proposed that have increased rigidity by filling the inside of a polyethylene casing with concrete. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-179976 Summary of the Invention [Problem to be solved by the invention]

[0005] If a vehicle that deviates from its lane collides with such a protective fence, the cross beam will deform significantly, absorbing the impact energy of the collision and preventing the vehicle from breaking through into the lane under construction, instead guiding it back into the lane.

[0006] However, if an errant vehicle collides with the safety fence at a speed or angle that exceeds the design conditions, unexpected collision energy may be applied to the safety fence itself, which could result in the fittings connecting the cross beams of the safety fence coming loose.

[0007] For this reason, there has long been a need for technology that prevents vehicles from breaking through into the lane under construction and guides them into the driving lane, even when such unexpected collision energy is applied to the guardrail, without the fittings connecting the cross beams of the guardrail coming loose.

[0008] Therefore, the present invention has been devised in consideration of the above-mentioned problems, and its purpose is to provide a guardrail, a cross beam for the guardrail, and a connecting structure for the cross beam for the guardrail that prevents vehicles from breaking through into the lane under construction and can guide them into the travel lane, even if unexpected collision energy is applied to the guardrail. [Means for solving the problem]

[0009] A protective fence according to a first aspect of the present invention is a protective fence in which multiple stages of cross beams are attached to posts, and at least one end of the uppermost cross beam is provided, from its base end to its tip, with a base end that is narrower than the cross beam, a first male fitting portion that is wider than the base end, a protruding portion that is narrower than the first male fitting portion, and a second male fitting portion that is wider than the protruding portion and narrower than the first male fitting portion, in this order; and at the other end of the cross beam, from its tip to its base end, with an opening that can guide and insert the base end, a first female recess that is wider than the opening and into which the first male fitting portion can be fitted, an insertion portion that is narrower than the first female recess and into which the protruding portion can be inserted, and a second female recess that is wider than the insertion portion and narrower than the first female recess and into which the second male fitting portion can be fitted, in this order. The base end portion and the first male fitting portion are extended so as to be able to be shared between the uppermost cross beam and one or more lower cross beams. It is characterized by:

[0010] The protective fence of the second invention is characterized in that, in the first invention, the base end is a steel pipe with a rectangular cross section, and the first male fitting portion, the protrusion portion, and the second male fitting portion are all made of steel plate.

[0012] No. 3 The protective fence according to the invention is: First invention or second invention The present invention is further characterized in that the protrusion and the second male fitting portion are extended so as to be able to be shared between the uppermost cross beam and one or more lower cross beams.

[0013] No. 4 The cross beam for a protective fence according to the present invention is a cross beam for a protective fence that is erected on at least the uppermost support post of the protective fence, and is provided at one end side, from its base end to its tip end, with a base end that is narrower than the cross beam, a first male fitting portion that is wider than the base end, a protruding portion that is narrower than the first male fitting portion, and a second male fitting portion that is wider than the protruding portion and narrower than the first male fitting portion, in this order; and at the other end side, from its tip end to its base end, with an opening that can guide and insert the base end therethrough, a first female recess that is wider than the opening and into which the first male fitting portion can be fitted, an insertion portion that is narrower than the first female recess and into which the protruding portion can be inserted, and a second female recess that is wider than the insertion portion and narrower than the first female recess and into which the second male fitting portion can be fitted, in this order. The base end portion and the first male fitting portion are extended so as to be able to be shared between the uppermost cross beam and one or more lower cross beams. It is characterized by:

[0014] No. 5The connecting structure for cross beams for a protective fence according to the present invention is a connecting structure for cross beams for a protective fence that are installed at least at the top of the posts of the protective fence, and one end side of a first cross beam is provided, from its base end to its tip, with a base end that is narrower than the cross beam, a first male fitting portion that is wider than the base end, a protruding portion that is narrower than the first male fitting portion, and a second male fitting portion that is wider than the protruding portion and narrower than the first male fitting portion, in this order. The other end side of the second cross beam connected to the first cross beam is provided, from its tip to base end, with an opening through which the base end is guided and inserted, a first female recess that is wider than the opening and into which the first male fitting portion is fitted, an insertion portion that is narrower than the first female recess and into which the protrusion is inserted, and a second female recess that is wider than the insertion portion and narrower than the first female recess and into which the second male fitting portion is fitted. The base end portion and the first male fitting portion are extended so as to be able to be shared between the uppermost cross beam and one or more lower cross beams. It is characterized by: [Effects of the Invention]

[0015] According to the present invention having the above-mentioned configuration, when a tensile load or a bending load is applied to the cross beam as a result of the collision energy of the vehicle, the first male fitting portion that fits into the first female recess can first resist this. As a result, the male fitting portion and the female recess that connect the cross beams do not come off each other, preventing the vehicle from breaking through and guiding it to the driving lane.

[0016] On the other hand, if a vehicle collides with the safety fence at a speed or angle exceeding the design conditions, the cross beams will be subjected to a tensile load or even a larger bending load. In such cases, the first male fitting portion described above can withstand this load, but the second male fitting portion can also withstand it. This ensures that even if unexpected collision energy is applied to the vehicle, the male fitting portion and the female recess portion that connect the cross beams will not come loose, preventing the vehicle from breaking through and guiding it to the driving lane. Even if the unexpected collision energy causes the first male fitting portion to deviate from the first female recess portion, the second male fitting portion will be firmly prevented from being pulled out of the second female recess portion, thereby maintaining the connection between the cross beams. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing the overall configuration of a safety fence to which the present invention is applied. [Figure 2] FIG. 2 is a diagram showing the structure of a support post used in a safety fence to which the present invention is applied. [Figure 3] FIG. 3(a) is a plan view of the uppermost cross beam among the cross beams, and FIG. 3(b) is a side view thereof. [Figure 4] FIG. 4 is an enlarged plan view of a male fitting portion provided on one end of the beam. [Figure 5] FIG. 5 is an enlarged plan view of a female recess provided on the other end side of the beam. [Figure 6] FIG. 6 is a diagram showing an example in which, when adjacent cross beams are connected to each other, the female recess of one cross beam is inserted into the male fitting portion of the other cross beam from above. [Figure 7] FIG. 7 is an enlarged plan view showing the male fitting portion and the female recess portion fitted together. [Figure 8] FIG. 8 is a diagram showing an example in which not only the uppermost cross beam but also lower cross beams are attached to the base end portion. [Figure 9]FIG. 9 is a diagram showing an example in which the second male fitting portion and the protrusion are extended downward so that they can be shared with one or more horizontal beams at a lower level. [Figure 10] FIG. 10 is a diagram for explaining a form in which a protective fence in which the posts are integrated with the cross beams is transported independently and then installed. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, a guardrail and a cross beam for a guardrail to which the present invention is applied will be described in detail with reference to the drawings.

[0019] As shown in FIG. 1, a protective fence 1 to which the present invention is applied comprises support posts 2 erected at predetermined intervals and cross beams 3 erected between the support posts 2 in multiple stages.

[0020] As shown in FIG. 2, the support pillar 2 is made of a steel pipe with a rectangular cross section, but is not limited to this and may be made of, for example, an H-shaped steel or any other configuration may be applied.

[0021] A metal anchor plate 21 is fixed by welding to the lower end of the support column 2. The anchor plate 21 has through holes (not shown) formed at multiple locations, and anchor bolts 23 are inserted into these through holes (not shown).

[0022] FIG. 3(a) is a plan view of the uppermost cross beam 3a of the cross beams 3, and FIG. 3(b) is a side view thereof.

[0023] The cross beam 3a has a beam material 31a, a male mating portion 4 provided on one end side of the beam material 31a (the end side in the A direction in the figure), and a female recess 5 provided on the other end side of the beam material 31a (the end side in the B direction in the figure).

[0024] The beam 31a is made of a metal pipe, and may be made of, for example, a steel pipe, or may be made of a rod-shaped body with a solid interior. The beam 31a has one or more through-holes 32 that penetrate vertically. The through-holes 32 are configured to a size that allows the above-mentioned support 2 to be inserted therethrough, and the support 2 is actually inserted and fixed.

[0025] The male fitting portion 4 is roughly divided into a first male fitting portion 41 provided on the base end side and a second male fitting portion 43 provided on the tip side of the first male fitting portion 41.

[0026] The female recess 5 is roughly divided into a first female recess 51 provided on the tip side and a second female recess 53 provided on the base end side of the first female recess 51.

[0027] Such cross beams 3a can be connected by fitting the male fitting portion 4 on one end side of one adjacent cross beam 3a with the female recess 5 on the other end side of the other cross beam 3a. Specifically, the first male fitting portion 41 of the male fitting portion 4 is fitted into the first female recess 51 of the female recess 5, and the second male fitting portion 43 of the male fitting portion 4 is fitted into the second female recess 53 of the female recess 5.

[0028] 4 is an enlarged plan view of the male fitting portion 4 provided at one end side of the beam 31a (the end side in the direction A in FIG. 3). The male fitting portion 4 is provided with a base end portion 34, a first male fitting portion 41, a protruding portion 42, and a second male fitting portion 43 in this order from its base end to its tip end (in the direction C in FIG. 4).

[0029] The base end 34 is made of a steel pipe with a rectangular cross section and is provided on one end of the beam 31a. The base end 34 is made to have a reduced width, that is, a smaller width size than the cross beam 3. When attaching the base end 34 to the beam 31a, a recess 35 is formed in advance by laser machining one end of the beam 31a to form a recess that matches the outer dimensions of the base end 34. The outer shell of the base end 34 is then fitted into this recess 35 and fixed by welding to attach the base end 34.

[0030] The cross-sectional shape of the base end 34 is not limited to a rectangular shape, but may be any other cross-sectional shape, including a circular shape. In such a case, the recess 35 is formed in a concave shape that follows the outer shape of the base end 34, and thus attachment is possible in the same way.

[0031] The first male fitting portion 41 described above is attached to the base end portion 34 by welding. The first male fitting portion 41 is configured to have a larger width than the base end portion 34, i.e., an enlarged size. This first male fitting portion 41 is in the form of a flat plate, and specifically, a steel plate may be used as is. However, this first male fitting portion 41 is not limited to a flat plate shape, and can be substituted with any other shape as long as it is wider than the base end portion 34.

[0032] As shown in Figure 3(b), the base end 34 and the first male fitting portion 41 extend downward from the uppermost beam 31a, so that the base end 34 and the first male fitting portion 41 can be shared with other beams 31 located below.

[0033] The first male fitting portion 41 and the second male fitting portion 43 are connected by welding or the like via a protrusion 42. This protrusion 42 is narrower in the width direction than the first male fitting portion 41. The protrusion 42 is in the form of a flat plate, and specifically, a steel plate may be used as is. In this embodiment, the protrusion 42 is configured as a flat plate-like protrusion 42 that is disposed just approximately perpendicular to the flat first male fitting portion 41. However, the protrusion 42 is not limited to being embodied in the form of a flat plate, and may be substituted with any other form as long as it is narrower in width than the first male fitting portion 41 and is continuous with the second male fitting portion 43.

[0034] The second male fitting portion 43 is configured to have a size that is wider than the protruding portion 42 and narrower than the first male fitting portion 41. This second male fitting portion 43 is in the form of a flat plate, and specifically, a steel plate may be used as is. However, this second male fitting portion 43 is not limited to a flat plate shape, and can be substituted with any other shape as long as it is wider than the protruding portion 42 and narrower than the first male fitting portion 41.

[0035] 5 is an enlarged plan view of the female recess 5 provided on the other end side of the beam 31a (the end side in the direction B in FIG. 3). The female recess 5 is provided with an opening 50, a first female recess 51, an insertion portion 52, and a second female recess 53 in this order from its tip to its base end (direction D in FIG. 5).

[0036] The opening 50 is configured with a size that allows the base end portion 34 to be guided and inserted during mating. More specifically, the opening 50 is formed by a flange portion 312 provided on the end surface 311 of the beam 31a. The flange portion 312 is configured as a flat metal plate, extending from both ends inward in the width direction. The flange portion 312 is configured to protrude inward in the width direction beyond the first female recess 51 so as to form an opening 50 that is narrower than the first female recess 51 described below. In this case, the flange portion 312 is configured to form an opening 50 that is narrower than the first male mating portion 41 that is mated with the first female recess 51. During mating, the base end portion 34 can be guided through the flange portion 312.

[0037] The first female recess 51 has a concave shape that is wider than the opening 50. The first female recess 51 is configured with a shape and size that allows the first male fitting portion 41 to fit therein. In the example of FIG. 5, on the premise that the first male fitting portion 41 is configured in a flat plate shape, the first female recess 51 is also formed to be a groove that is approximately flat in plan view. However, if the first male fitting portion 41 is configured in a shape other than a flat plate shape, the first female recess 51 will also be configured with a shape and size that allows it to fit therein accordingly.

[0038] The insertion portion 52 is configured with a shape that is narrower than the first female recess 51. The insertion portion 52 is configured with a shape and size that allow the protrusion 42 to be inserted therethrough. Similarly, when the protrusion 42 is configured with a shape other than a flat plate shape, the insertion portion 52 is configured with a shape and size that allows insertion therethrough that corresponds to the configuration of the protrusion 42. In this case, the insertion portion 52 is configured with a shape and size that is narrower than the second female recess 53 described below and narrower than the second male fitting portion 43 that fits into the second female recess 53.

[0039] The second female recess 53 has a concave shape that is wider than the insertion portion 52 and narrower than the first female recess 51. The second female recess 53 is configured with a shape and size that allows the second male fitting portion 43 to fit therein. In the example of FIG. 5, assuming that the second male fitting portion 43 is configured in a flat plate shape, the second female recess 53 is also formed to be a substantially flat groove in a plan view. However, if the second male fitting portion 43 is configured in a shape other than a flat plate shape, the second female recess 53 will also be configured with a shape and size that allows it to fit therein.

[0040] When forming the first female recess 51, the insertion portion 52, and the second female recess 53 having the above-described configuration, they are shaped into the desired shape by, for example, laser processing or the like.

[0041] As shown in FIG. 3(b), the female recess 5 may be provided with a metal reinforcing plate 315 for further reinforcing the upper and lower surfaces thereof.

[0042] Next, a method for connecting adjacent cross beams 3a by fitting the male fitting portion 4 and the female recessed portion 5 having the above-described configuration together will be described.

[0043] As shown in FIG. 6, when adjacent cross beams 3a are connected to each other, the female recess 5 of one cross beam 3a is fitted into the male fitting portion 4 of the other cross beam 3a from above and inserted through the male fitting portion 4.

[0044] FIG. 7 is an enlarged plan view showing the male fitting portion 4 and the female recess 5 fitted together.

[0045] The opening 50 of the female recess 5 accommodates the base end 34 of the male fitting portion 4. Furthermore, the first male fitting portion 41 is fitted into the first female recess 51. The protruding portion 42 is inserted into the insertion portion 52. Furthermore, the second male fitting portion 43 is fitted into the second female recess 53.

[0046] When fitting, the base end portion 34 is guided through the flange portion 312 in the opening portion 50 , so that the base end portion 34 can be accommodated in the opening portion 50 .

[0047] In such a connection structure, when a tensile load or a bending load is applied to the cross beam 3 as a result of the application of vehicle collision energy, the first male fitting portion 41 that fits into the first female recess 51 can first resist this. As described above, the flange portion 312 is configured to form an opening 50 that is narrower than the first female recess 51 and the first male fitting portion 41 that fits therein. Therefore, even when a tensile load or a bending load is applied, the first male fitting portion 41 can be prevented from being pulled out of the first female recess 51 through the flange portion 312.

[0048] As a result, even when collision energy from a vehicle is applied, the male fitting portions 4 and the female recessed portions 5 for connecting the cross beams 3a to each other do not come off each other, preventing the vehicle from breaking through and guiding it to the driving lane.

[0049] On the other hand, if a vehicle collides with the safety fence at a speed or angle that exceeds the design conditions, a tensile load or an even larger bending load will be applied to the cross beam 3. In such a case, the first male fitting portion 41 described above can withstand this, but in addition, the second male fitting portion 43 can also withstand this. As described above, the insertion portion 52 is narrower than the second female recess 53 and the second male fitting portion 43 that fits therein. Therefore, even when a tensile load or a bending load is applied, the second male fitting portion 43 can be prevented from being pulled out of the second female recess 53 through the insertion portion 52.

[0050] As a result, even if unexpected collision energy is applied to the vehicle, the male fitting portion 4 and the female recessed portion 5 for connecting the cross beams 3a to each other will not come off each other, preventing the vehicle from breaking through and guiding it to the driving lane. Even if unexpected collision energy causes the first male fitting portion 41 to deviate from the first female recessed portion 51, the second male fitting portion 43 is firmly prevented from being pulled out of the second female recessed portion 53, making it possible to maintain the connection state between the cross beams 3a.

[0051] In the present invention, the second female recess 53 has a recessed shape that is narrower than the first female recess 51. Therefore, as shown in Fig. 7, the thickness from the second female recess 53 to the side end surface can be made sufficiently thick, which prevents breakage from the second female recess 53 toward the side end surface.

[0052] The present invention is not limited to the above-described embodiment. Fig. 8 shows an example in which not only the uppermost cross beam 3a but also lower cross beams 3b and 3c are attached to the base end portion 34. One end of the lower cross beams 3b and 3c is provided with a recess 35 into which the outer periphery of the base end portion 34 can be fitted, similar to the cross beam 3a, and the other end is provided with a female recess 5. In other words, the configuration of the cross beams 3b and 3c is the same as that of the cross beam 3a described above, and therefore the same components and members are used, and the following description will be omitted by assigning the same reference numerals.

[0053] In this case, the base end portion 34 and the first male fitting portion 41 extend downward so as to be shared between the uppermost cross beam 3a and one or more lower cross beams 3b, 3c. By attaching the cross beams 3a-3c to the base end portion 34, the functions of the base end portion 34 and the first male fitting portion 41 of the male fitting portion 4 can be similarly performed not only on the cross beam 3a but also on the cross beams 3b, 3c. Similarly, the cross beams 3b, 3c have female recesses 5 on their other ends, so they can similarly fit with the male fitting portion 4. In this case, it is sufficient that at least the female recesses 5 of the cross beams 3b, 3c have the openings 50 and the first female recesses 51. Since the cross beams 3b, 3c only have the configurations of the base end portion 34 and the first male fitting portion 41 of the male fitting portion 4, it is sufficient that the female recesses 5 also have the corresponding openings 50 and the first female recesses 51.

[0054] In the present invention, if the uppermost cross beam 3a is provided with the second male fitting portion 43 and the protruding portion 42, and also with the second female recessed portion 53 and the insertion portion 52, it can adequately withstand even unexpected collision energy. The reason for this is that unexpected collision energy is often applied to the safety fence 1 when a large vehicle such as a truck or bus hits it, and in response to this, it is necessary to firmly prevent the connection at the uppermost cross beam 3a from coming loose.

[0055] However, as shown in Fig. 9, the second male fitting portion 43 and the protruding portion 42 may be extended downward so that they can be shared with one or more lower cross beams 3b, 3c. In such a case, a second female recess 53 and an insertion portion 52 are provided so that the second male fitting portion 43 can be fitted to the cross beams 3b, 3c as well.

[0056] Furthermore, the present invention may be applied to a protective fence 1 in which the posts 2 are integrated with the cross beams 3, and the protective fence 1 is transported and installed independently, as shown in Figure 10. The posts 2 are inserted into the through holes 32 of the cross beams 3 and fixed by welding or the like. At this time, the anchor plates 21 and anchor bolts 23 fixed to the lower ends of the posts 2 may also remain attached.

[0057] With the cross beams 3 and the posts 2 integrated in this manner, anchor bolts 23 are inserted into holes 61 provided in the road surface 6, making it possible to install the protective fence 1. [Explanation of symbols]

[0058] 1 Protective fence 2 pillars 3 crossbeam 4 Male mating part 5 Female recess 6 Road surface 21 Anchor plate 23 Anchor bolt 31 Beam material 32 Through hole 34 Proximal end 35 recess 41 First male fitting part 42 Protrusion 43 Second male mating part 50 Opening 51 First female recess 52 Insertion part 53 Second female recess 61 holes

Claims

1. A protective fence in which multiple cross beams are provided on the posts, At least one end of the uppermost cross beam is provided, from its base end to its tip, with a base end that is narrower than the cross beam, a first male fitting portion that is wider than the base end, a protruding portion that is narrower than the first male fitting portion, and a second male fitting portion that is wider than the protruding portion and narrower than the first male fitting portion, in this order; On the other end side of the cross beam, from the tip to the base end thereof, there are provided in order: an opening into which the base end portion can be guided and inserted; a first female recess which is wider than the opening and into which the first male fitting portion can be fitted; an insertion portion which is narrower than the first female recess and into which the protrusion portion can be inserted; and a second female recess which is wider than the insertion portion and narrower than the first female recess and into which the second male fitting portion can be fitted; The base end portion and the first male fitting portion are extended so as to be able to be shared between the uppermost cross beam and one or more lower cross beams. A protective fence characterized by:

2. The base end is a steel pipe having a rectangular cross section, The first male fitting portion, the protruding portion, and the second male fitting portion are all made of steel plates. The protective fence according to claim 1,

3. Furthermore, the protrusion and the second male fitting portion are extended so as to be able to be shared between the uppermost cross beam and one or more lower cross beams.

3. The protective fence according to claim 1 or 2, characterized in that:

4. A cross beam for a protective fence that is installed at least at the top of a support post of the protective fence, The one end side is provided, from its base end to its tip end, with a base end portion narrower than the cross beam, a first male fitting portion wider than the base end portion, a protruding portion narrower than the first male fitting portion, and a second male fitting portion wider than the protruding portion and narrower than the first male fitting portion, in this order; The other end side is provided, from the tip to the base end, with an opening through which the base end can be guided and inserted, a first female recess that is wider than the opening and into which the first male fitting portion can be fitted, an insertion portion that is narrower than the first female recess and into which the protruding portion can be inserted, and a second female recess that is wider than the insertion portion and narrower than the first female recess and into which the second male fitting portion can be fitted, in this order; The base end portion and the first male fitting portion are extended so as to be able to be shared between the uppermost cross beam and one or more lower cross beams. A cross beam for a protective fence characterized by the above.

5. A connecting structure for a cross beam for a protective fence that is installed at least at the top of a support post of the protective fence, One end side of the first cross beam is provided, from its base end to its tip end, with a base end portion that is narrower than the cross beam, a first male fitting portion that is wider than the base end portion, a protruding portion that is narrower than the first male fitting portion, and a second male fitting portion that is wider than the protruding portion and narrower than the first male fitting portion, in this order; The other end side of the second cross beam connected to the first cross beam is provided, from its tip to its base end, with an opening through which the base end is guided and inserted, a first female recess which is wider than the opening and into which the first male fitting portion is fitted, an insertion portion which is narrower than the first female recess and into which the protruding portion is inserted, and a second female recess which is wider than the insertion portion and narrower than the first female recess and into which the second male fitting portion is fitted, in this order; The base end portion and the first male fitting portion are extended so as to be able to be shared between the uppermost cross beam and one or more lower cross beams. A connecting structure of cross beams for a protective fence, characterized by the above.

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