Impact absorption fence

Abstract

To provide a high-performance impact absorption fence while avoiding major cost increase.SOLUTION: An impact absorption fence has pillars 20 erected on base plates 25 fixed to the ground 10 via support shafts 24 so that they can tilt, and heads of the pillars 20 are connected to mountain-side anchors by mountain-side tie ropes with shock absorbers. The pillars 20 are equipped with an auxiliary impact absorption mechanism, which includes an auxiliary mountain-side tie rope 66 routed along a length of the pillars 20, a mooring shaft 28 attached to the base plate 25 at a distance from the support shafts 24 on a mountain side of a slope and for mooring a free end of the auxiliary mountain-side tie rope, and an auxiliary impact absorption device 65 attached to the base plate 25 at a distance from the mooring shaft 28 on the mountain side of the slope. When the pillars 20 tilt with the support shafts 24 being a center, tension in the auxiliary mountain-side tie rope 66 increases, and the tension of the auxiliary mountain-side tie rope 66 is supported by the base plate 25.SELECTED DRAWING: Figure 7A

Description

[Technical Field]

[0001] The present invention relates to an impact absorbing fence that captures falling objects such as falling rocks and collapsed earth and sand. [Background technology]

[0002] A typical impact-absorbing fence is equipped with at least multiple posts (terminal posts and intermediate posts) erected at a specified distance apart, and a protective net stretched horizontally between adjacent posts. The flexural deformation of the protective net and the bending strength of the posts absorb the kinetic energy of falling objects such as falling rocks.

[0003] Patent Document 1 discloses an impact absorbing fence in which multiple rope materials are laid horizontally between adjacent posts, shock absorbers are provided near the ends of each rope material, and a protective net formed on a span-by-span basis enhances energy absorption performance. Patent documents 2 and 3 disclose that a mountain-side anchor is provided on the mountain slope, a mountain-side support rope is stretched between the mountain-side anchor and the head of the support pillar, and a shock absorber is interposed between the mountain-side support rope and the mountain-side anchor, so that when the support pillar deforms toward the valley side of the slope when an impact is received, the shock absorber exerts a damping effect. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-273828 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-32032 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-185514 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned impact absorbing fence has a simplified structure in order to keep costs down. As a result, the energy absorption capacity of the impact absorbing fence was limited to around 300Kj. Increasing the energy absorption capacity to 500-1000Kj would not only require new improvements, but would also be expected to result in a significant increase in costs.

[0006] The present invention has been made in view of the above points, and aims to provide a high-performance impact absorbing fence while avoiding a significant increase in cost. [Means for solving the problem]

[0007] The present invention provides an impact absorbing fence comprising a plurality of tiltable support posts set up at intervals and a protective net stretched across a plurality of spans of the support posts, wherein the support posts are set up tiltably via support shafts on a base plate fixed to the ground, and the support posts are equipped with an auxiliary shock absorbing mechanism comprising an auxiliary mountain side tie rope routed along the length of the support post, a mooring shaft attached to the base plate at a distance from the support shaft towards the mountain side of the slope and for mooring the free end of the auxiliary mountain side tie rope, and one or more auxiliary shock absorbers attached to the base plate at a distance from the mooring shaft towards the mountain side of the slope and for gripping the free end of the auxiliary mountain side tie rope, and wherein when the support post tilts around the support shaft, the tension in the auxiliary mountain side tie rope increases and the tension of the auxiliary mountain side tie rope is supported by the base plate. In another form of the present invention, when the tension of the auxiliary mountain side back rope exceeds the slip tension of the auxiliary buffer device, slip occurs between the auxiliary mountain side back rope and the auxiliary buffer device, thereby attenuating part of the tension generated in the auxiliary mountain side back rope. In another embodiment of the invention, the support column having the auxiliary shock absorbing mechanism is a terminal support column. In another form of the present invention, a plurality of upper ropes, each having an independent buffer function for each span of the support, are linked and laid horizontally between the heads of adjacent support columns, and a plurality of lower ropes, each having an independent buffer function for each span of the support columns, are linked and laid horizontally between the bottom parts of adjacent support columns, and friction sliding type buffers are installed near both ends of the upper and lower ropes, with excess rope length formed outside the buffers, and when tension above a certain level is applied to the upper and lower ropes, sliding occurs between the ropes and the buffers, thereby attenuating the tension. In another form of the present invention, the upper and lower edges of the protective net are moored to the multiple upper end ropes and multiple lower end ropes via connectors so as to be able to move laterally, and the left and right side edges of the protective net are attached to terminal supports. In another embodiment of the present invention, the protective net is a belt-like net formed by linking a plurality of ring units in a chain to form a net. [Effects of the Invention]

[0008] The present invention has at least one of the following effects. <1> By simply providing a simple auxiliary shock-absorbing mechanism, it is possible to significantly improve the shock-absorbing performance of the shock-absorbing fence while suppressing increases in manufacturing costs of the shock-absorbing fence. <2> The amount of slippage (amount of tension reduction) between the auxiliary mountain-side support rope and the auxiliary buffer increases per tilt angle of the support (terminal support), so the more the support falls, the greater the tilt resistance provided by the auxiliary buffer mechanism. <3> The buffering effect of the auxiliary buffering mechanism occurs not only in the initial stage of tilting of the support pole but also continues thereafter, so the buffering function is exerted for a longer period of time, thereby increasing the buffering performance of the impact absorbing fence. <4> The tension of the auxiliary mountain-side stay rope is supported by the base plate via an auxiliary buffer. This eliminates the need to install additional mountain side anchors to support the auxiliary mountain side support ropes or to connect them to a common mountain side anchor, reducing the burden in terms of costs and construction. <5> By installing the auxiliary shock absorbers on the base plate at a low location rather than on the head of the support column at a high location, the installation of the auxiliary shock absorbers can be done safely and easily. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a partially cutaway front view of an impact absorbing fence according to the present invention. [Figure 2] Enlarged view of the terminal section of the impact absorbing fence with some parts omitted [Figure 3] Perspective view of the support pillar with the middle section omitted [Figure 4A] Exploded view of the lower part of the intermediate support and base plate [Figure 4B] A perspective view of the connection between the lower part of the terminal support and the base plate [Figure 5] Exploded view of shock absorber [Figure 6A] Cross section of VI-VI in Figure 1 [Figure 6B] Horizontal cross section of the connection between the lower part of the intermediate support and the base plate [Figure 7A] Cross-sectional view of VII-VII in Figure 1 [Figure 7B] Horizontal cross section of the connection between the bottom of the terminal support and the base plate [Figure 8] An explanatory diagram of the function of the auxiliary buffer mechanism installed on the terminal support BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] <1> Overview of the impact absorbing fence 1 and 2 show an example of an impact absorbing fence according to the present invention. The impact absorbing fence comprises posts 20 (terminal posts 20a, intermediate posts 20b) erected at appropriate intervals on a slope 10 or the like, upper end ropes 31 and lower end ropes 32 made of wire rope and having a shock-absorbing function, which are erected independently in span units between the heads and bottoms of adjacent posts 20, and a belt-shaped protective net 40 whose upper and lower edges are moored to multiple sets of upper and lower end ropes 31, 32 and whose total length allows it to be laid horizontally across multiple spans. The main components are described in detail below.

[0012] <2> pillar Referring to FIG. 3, the support columns 20 include terminal support columns 20a and intermediate support columns 20b, and have the same basic configuration. The support column 20 has a support column body 21, a base plate 25, and a support shaft 24 that pivots between the lower part of the support column body 21 and the base plate 25.

[0013] <2.1> Support body The support pillar body 21 is a rigid member for supporting the upper and lower edges of the protective net, and is made of a known rigid member such as a steel material or a concrete pillar. Referring to Figure 3, the upper part of the support body 21 has multiple through holes 21a for inserting the upper end rope 31, and the upper and lower parts of the support body 21 have multiple bracket-shaped connecting elements 22 protruding therefrom for connecting multiple stay rope materials. The lower part of the support column body 21 is provided with a connecting piece 23 for rotatably connecting to a base plate 25 via a support shaft 24 .

[0014] <2.2> Base plate Referring to FIG. 4A, the base plate 25 is a support member that comes into contact with the ground and supports the support column body 21, and is fixed to the ground by a plurality of anchor bolts 12. The base plate 25 exemplified in this embodiment will be described. A pair of standing pieces 27, 27 are provided at a predetermined distance from the center of the upper surface of the landing plate 26 of the base plate 25. The pair of standing pieces 27, 27 are provided with a plurality of shaft holes 27a along the longitudinal direction of the standing pieces 27. The multiple shaft holes 27a are used to insert the support shaft 24, the mooring shaft 28, and the lower end rope 32.

[0015] The base plate 25 for the intermediate support column is not provided with a mooring shaft 28 (FIG. 6B), but the base plate 25 for the end support column receives a mooring shaft 28 (FIG. 7B). In the case of the base plate 25 for a terminal support, the support shaft 24 and the mooring shaft 28 are provided in shaft holes near both ends of a pair of upright pieces 27, 27.

[0016] <2.3> Pivot structure between the support body and base plate The support column body 21 is pivotally supported by a support shaft 24 so as to be tiltable relative to a base plate 25 . In this example, a configuration will be described in which the connecting piece 23 of the support body 21 is inserted between a pair of standing pieces 27, 27, and the support shaft 24 is inserted between the standing pieces 27, 27 and the connecting piece 23.

[0017] The support pillar body 21 can be tilted not only in the direction of inclination of the slope around the support shaft 24, but also in the direction intersecting the support shaft 24 (diagonally across the slope). To pivot the support pillar body 21 in the direction intersecting the support shaft 24, for example, the groove width of the pair of upright pieces 27, 27 may be made wider than the plate thickness of the connecting piece 23, and the bolt hole of the connecting piece 23 may be formed with a larger diameter than the support shaft 24.

[0018] <3> Upper and lower ropes As shown in FIG. 1, an upper rope 31 is laid between the heads of adjacent posts 20, and a lower rope 32 is laid between the bottoms of adjacent posts 20. The upper end rope 31 and the lower end rope 32 are wire ropes that support the upper and lower edges of the protective net 40, and are independent for each span.

[0019] The upper end rope 31 and the lower end rope 32 are inserted through the through holes 24 provided at the top and bottom of the support 20, and the ends of the upper end rope 31 and the lower end rope 32 are gripped by the buffers 50 (Fig. 3).

[0020] <3.1> Rope length The upper end rope 31 and the lower end rope 32 are independent for each span and have a total length longer than the span length of the support 20.

[0021] <3.2> Extra length The upper end rope 31 and the lower end rope 32 each form an excess length portion 31a, 32a in the range extending outward from the buffer 50. These extra lengths 31 a and 32 a are the allowable lengths of the upper end rope 31 and the lower end rope 32 for slip (sliding).

[0022] <3.3> Buffers for upper and lower rope ends The buffer 50 is a device for attenuating the tension of the ropes when tension exceeding a certain level acts on each of the upper end ropes 31 and the lower end ropes 32. The number of buffers 50 to be installed on each of the end ropes 31, 32 can be selected as appropriate.

[0023] Regarding the friction sliding type shock absorber 50 illustrated in FIG. 5, the shock absorber 50 comprises a pair of clamping plates 51, 51 having half grooves capable of gripping the upper and lower end ropes 31, 32, a U-shaped fastening bolt 52 that can be inserted through the pair of clamping plates 51, 51, and a nut 53. When the tension of each of the end ropes 31, 32 held between the pair of holding plates 51 exceeds the gripping force, each of the end ropes 31, 32 slips and attenuates the kinetic energy.

[0024] <4> Spacing rope As shown in FIG. 1, a spacing rope 34 is laid across the heads of adjacent posts 20 . In addition to maintaining a constant span between adjacent columns 20, the spacing ropes 34 also function to transmit loads to the terminal columns 20a through the multiple spacing ropes 34 when an attack is received.

[0025] <5> Stay rope for support In order to prevent the support columns 20 (terminal support columns 20a, intermediate support columns 20b) from tilting toward the slope valley side, a mountain side backing rope 61 is stretched between the mountain side anchor 11 and the head of the support column 20. A buffer device 60 is installed at the end or middle of the mountain side support rope 61.

[0026] <5.1> Stay rope of intermediate support A mountain side support rope 61 with a shock absorber 60 and a mountain side positioning rope 62 are connected between the head of the intermediate support 20b and the mountain side anchor 11 (FIG. 6A).

[0027] <5.2> Stay ropes for terminal supports A mountain side support rope 61 with a shock absorber 60 and a mountain side positioning rope 62 are also connected between the head of the terminal support 20a and the mountain side anchor 11 (FIG. 7A). In addition to the mountain side support rope 61, the terminal support 20a also connects a side support rope 63 and a side positioning rope 64 (Fig. 2). The side support rope 63 connects the head of the terminal strut 20a to the side anchor 13, and the side positioning rope 64 connects the bottom of the terminal strut 20a to the side anchor 13. Buffers 60 are also installed at the ends or middle of the side support ropes 63.

[0028] <5.3> Buffer for stay rope The buffer device 60 is a friction sliding type buffer device that has a pair of clamping plates with half grooves that can grip the back ropes 61, 63, and a plurality of fastening bolts and nuts that can fasten the pair of clamping plates together, and when a tension greater than a certain level acts on the mountain side back rope 61 or the lateral back rope 63, it allows sliding and reduces the tension of each back rope 61, 62. The friction sliding type shock absorber 60 may be, for example, the shock absorber described in Japanese Patent No. 6925674.

[0029] <6> protective net In this example, the protective net 40 is described as being made up of a protective net formed by linking together a plurality of ring units 41 in a chain-like manner to form a mesh-like structure, but the protective net 40 may also be made up of a known rope net.

[0030] As shown in FIGS. 1 and 2, the protective net 40 has a plurality of ring units 41. The ring unit 41 is made by forming a rigid wire material such as a steel wire or a wire into a circular shape. The diameter of the ring unit 41 can be selected as appropriate, but in practice it is set to a size of about 30 to 50 cm.

[0031] <6.1> Total length of protective net The protective net 40 has a total length spanning multiple spans in the extension direction of the fence. The protective net 40 is brought to the site in a length that can be carried in, and the entire length of the protective net 40 is adjusted by connecting the nets together using connecting devices 30 such as shackles.

[0032] <6.2> Installation position of the protective net on the support pole The protective net 40 is disposed on the downstream side (slope valley side) of the support 20.

[0033] <6.3>Means for attaching protective nets The protective net 40 is attached by anchoring its upper and lower edges to the upper and lower parts of the plurality of posts 20, respectively. That is, the upper edge of the protective net 40 is moored to an upper end rope 31 provided on each span via a connector 30 such as a shackle, and the lower edge of the protective net 40 is also moored to a lower end rope 32 provided on each span via a connector 30. Between the protection net 40 and the intermediate support 20b, the upper and lower edges of the protection net 40 are anchored to the upper and lower parts of the intermediate support 20b.

[0034] The left and right sides of the protective net 40 are moored to separate vertical ropes 33 provided along the terminal poles 20a via connectors 30 such as shackles.

[0035] <6.4> Wire mesh 1, in order to prevent small-diameter debris from passing through the protective net 40, a wire mesh 42 may be attached to one side of the protective net 40 as needed. The wire mesh 42 may be, for example, a diamond-shaped wire mesh. The mesh size of the wire mesh 42 is smaller than the diameter of the ring unit 41. The periphery of the wire mesh 42 is attached by connecting it to the upper and lower end ropes 31, 32 and the vertical rope 33 with a connecting coil or the like.

[0036] <7> Auxiliary shock absorber added to terminal support As mentioned above, the mountain side support rope 61 and the side support rope 63 are connected to the top of the terminal support 20a.

[0037] This will be described with reference to FIG. 4B, 7A and 7B. In the present invention, an auxiliary shock absorbing mechanism is added to further improve the impact absorbing performance of the impact absorbing fence. The auxiliary buffer mechanism comprises an auxiliary mountain side support rope 66 arranged along the longitudinal direction of the terminal support 20a, a mooring shaft 28 mounted on the base plate 25 at a distance from the support shaft on the mountain side of the slope, and one or more auxiliary buffer devices 65 mounted on the base plate 25. The cushioning performance of the auxiliary cushioning mechanism is proportional to the number of auxiliary cushioning devices 65 installed.

[0038] <7.1> Auxiliary mountain side rope One end of the auxiliary mountain side support rope 66 is fixed to the head of the terminal support 20a, and the auxiliary mountain side support rope 66 is routed along the terminal support 20a, with the free end of the auxiliary mountain side support rope 66 being held by an auxiliary buffer 65 provided on the base plate 25 of the terminal support 20a. The auxiliary mountain side back rope 66 has an excess length 66 a formed outside the auxiliary shock absorber 65 . The excess length 66a is the allowable slip (sliding) length of the auxiliary mountain-side back rope 66. Therefore, the total length of the excess length 66a is selected appropriately.

[0039] <7.2>Auxiliary shock absorber An auxiliary shock absorber 65 is provided on the mountain side of the upright pieces 27, 27 erected on the base plate 25. The auxiliary buffer 65 is a manual friction buffer device that receives a reaction force from the base plate 25 and grips the auxiliary mountain side support rope 66, and when the tension generated in the auxiliary mountain side support rope 66 exceeds a certain value (buffer 65), it allows the auxiliary mountain side support rope 66 to slide. The auxiliary shock absorber 65 is configured by, for example, a pair of clamping plates 65a, and a combination of a normal fastening bolt (hexagonal bolt) that can be inserted through the pair of clamping plates 65a, and a nut 65b. The auxiliary shock absorber 65 can be substituted by the shock absorber 50 already described.

[0040] In this example, a form in which the free end of the auxiliary mountain side support rope 66 is held by a single auxiliary buffer 65 is described, but multiple auxiliary buffers 65 may also be arranged in series on the free end of the auxiliary mountain side support rope 66. Even when a plurality of auxiliary shock absorbers 65 are arranged in series, a reaction force is obtained from the base plate 25.

[0041] <7.3>Mooring shaft A mooring shaft 28 is provided at the mountain side end of the upright pieces 27, 27 erected on the base plate 25, facing horizontally. The mooring shaft 28 is a guide member at the base of the support body 21 for bending the lower part of the auxiliary mountain side back rope 66 at a nearly right angle and sliding it. On the upright pieces 27, 27, the support shaft 24, the mooring shaft 28, and the auxiliary shock absorber 65 are arranged in this order from the slope valley side to the slope mountain side. The mooring shaft 28 can be installed by utilizing one of the openings 27 formed in the upright pieces 27, 27.

[0042] <7.4> Supporting member for auxiliary shock absorber An auxiliary shock absorber 65 is disposed on the mountain side surface of the upright pieces 27, 27, and the auxiliary shock absorber 65 is supported by the upright pieces 27, 27 of the base plate 25. The auxiliary shock absorbers 65 are arranged on the upright pieces 27, 27 so that the supporting force of the auxiliary mountain side support rope 66 can be obtained from the base plate 25.

[0043] <7.5> Why the reaction force of the auxiliary mountain-side stay rope is required on the base plate It is also possible to rely on the mountain side anchor 11 for the supporting force of the auxiliary mountain side stay rope 66. If the free end of the auxiliary mountain side support rope 66 is moored to the mountain side anchor 11 and the reaction force of the auxiliary mountain side support rope 66 is required from the mountain side anchor 11, installing the additional mountain side anchor 11 will require cost and effort. Furthermore, if the supporting force of the auxiliary mountain side support rope 66 is required to be provided by the mountain side anchor 11 that is also used for the mountain side support rope 66, the mountain side anchor 11 must be constructed to be large, which will increase the burden in terms of cost and construction.

[0044] In order to avoid such problems, in the present invention, the free end of the auxiliary mountain side stay rope 66 is supported by the base plate 25 via the mooring shaft and the auxiliary shock absorber 65. By configuring it in this way, the reaction force of the auxiliary mountain side stay rope 66 does not need to be provided by the mountain side anchor 11, and the buffering effect of the auxiliary buffer device 65 can be exerted.

[0045] <7.6> Positional relationship between the tilting center of the support and the tilting center of the auxiliary mountain-side support rope This will be explained with reference to Figure 8. The support column 20 (terminal support column 20a) tilts (pivots) around the support axis 24 at a radius R1 toward the valley side of the slope. The auxiliary mountain side stay rope 66 connected to the head of the support 20 (terminal support 20a) tilts (swivels) toward the slope valley side with a radius R2 centered on the mooring axis 28, following the tilt of the support 20. The radius R1 of the support 20 remains unchanged regardless of the tilt angle of the support 20, but the radius R2 of the auxiliary mountain side support rope 66 increases in length depending on the tilt angle of the support 20.

[0046] Regarding the positional relationship between the tilt center of the support pillar 20 and the tilt center of the auxiliary mountain side support rope 66, the tilt center (mooring axis 28) of the auxiliary mountain side support rope 66 is located at a position separated from the tilt center (support axis 24) of the support pillar main body 21 toward the slope side. This is because the auxiliary shock absorber 65 exerts a shock absorbing effect when the terminal support 20a tilts.

[0047] Since the tilt center of the auxiliary mountain side support rope 66 is eccentric and away from the tilt center of the terminal support pillar 20a, the tension of the auxiliary mountain side support rope 66 gradually increases in accordance with the tilt of the support pillar main body 21. In other words, the more the terminal support 20a falls, the greater the diameter difference G between the radius R1 of the terminal support 20a centered on the support axis 24 and the radius R2 of the auxiliary mountain side support rope 66 centered on the mooring axis 28, and the tension acting on the auxiliary mountain side support rope 66 gradually increases. The diameter difference G when the support 20 tilts, that is, the amount of slippage of the auxiliary mountain-side stay rope 66, is proportional to the distance (eccentric distance) between the two tilt centers.

[0048] In short, the mooring shaft 28 should be arranged relative to the base plate 25 so that when the support body 21 tilts around the support shaft 24, the tension in the auxiliary mountain side stay rope 66 increases.

[0049] <7.7> Installation location of auxiliary shock absorbers Regarding the arrangement structure of the auxiliary mountain side support rope 66, it is also possible to fix the tip of the auxiliary mountain side support rope 66 to the base plate 25 side and provide an auxiliary shock absorber 65 on the head side of the support body 21. If the auxiliary shock absorber 65 is provided on the head side of the support body 21, not only is the work of attaching the heavy auxiliary shock absorber 65 to a high place dangerous and difficult, but also the excess length 66a of the auxiliary mountain side support rope 66 hangs down on the head side of the support body 21, spoiling the scenery. If the auxiliary shock absorber 65 is provided on the lower side of the base plate 25, such adverse effects can be avoided and the auxiliary shock absorber 65 can be easily installed in a safe working environment.

[0050] [Dampening effect of impact absorbing fences] The damping effect when a falling object such as a rock strikes an impact absorbing fence will be explained below.

[0051] <1> Capture effect of protective net The upper and lower edges of the protective net 40 of the impact absorbing fence shown in FIG. 1 are anchored to the intermediate support poles 20b, and the left and right sides of the protective net 40 are connected to the terminal support poles 20a. When a collapsed object strikes a part of the impact surface of the protection net 40, the protection net 40 is deflected and deformed toward the downstream side of the slope. When the protection net 40 is deflected and deformed, it attenuates part of the kinetic energy of the collapsed object.

[0052] <2> Damping effect by the upper and lower end ropes and buffers As the protective net 40 deforms, the upper end rope 31 and the lower end rope 32 stretched across the impact span are pulled downstream, increasing the tension in the upper and lower end ropes 31, 32. When the tension in the upper and lower end ropes 31, 32 exceeds the slip tension (the gripping force of the ropes by the buffer 50), slip occurs between the upper and lower end ropes 31, 32 and the buffer 50, and part of the tension generated in the ropes 31, 32 is attenuated.

[0053] <3> Damping effect of mountain side support ropes and shock absorbers As the protective net 40 deforms, the intermediate supports 20b not only tilt toward the valley side of the slope, but also tilt in directions that bring the intermediate supports 20b closer to each other. As the intermediate support 20b tilts toward the valley side of the slope, the tension in the mountain side stay rope 61 increases, and this tension is supported by the mountain side anchor 11. When the tension in the mountain side support rope 61 exceeds the slip tension (the gripping force of the rope by the buffer device 60), slip occurs between the mountain side support rope 61 and the buffer device 60, which attenuates part of the tension generated in the mountain side support rope 61.

[0054] <4> Impact load transmission The impact load of the collapsed object acting on a part of the impact surface of the protection net 40 is transmitted through the protection net 40 to the terminal support 20a. Furthermore, the impact load of the collapsed object acting on a portion of the impact surface of the protective net 40 is transmitted to the terminal support 20a through the multiple spacing ropes 34.

[0055] <5> Damping effect by side stay ropes and shock absorbers When an impact load is transmitted to the terminal supports 20a located at both ends of the impact absorbing fence, the tension in the side support ropes 63 increases, and when the tension in the side support ropes 63 exceeds the slip tension (the gripping force of the ropes by the buffer 60), slip occurs between the side support ropes 63 and the buffer 60, attenuating part of the tension generated in the side support ropes 63.

[0056] <6> Damping effect by auxiliary shock absorber When the terminal support 20a tilts toward the slope valley or in the approaching direction of the support, the auxiliary buffer mechanism provided in the terminal support 20a functions as follows. As the terminal support 20a tilts, the tension in the auxiliary mountain side support rope 66 increases, and the tension in the auxiliary mountain side support rope 66 increases in proportion to the tilt angle of the terminal support 20a. The tension of the auxiliary mountain side stay rope 66 is supported by the anchor bolt 12 through the base plate 25.

[0057] When the tension in the auxiliary mountain side support rope 66 exceeds the slip tension (the gripping force of the rope by the auxiliary buffer 65), slip occurs between the auxiliary mountain side support rope 66 and the auxiliary buffer 65, reducing part of the tension generated in the auxiliary mountain side support rope 66.

[0058] The present invention does not cause slippage to occur evenly between the auxiliary mountain side support rope 66 and the auxiliary buffer device 65 without being affected by the tilt angle of the terminal support 20a.

[0059] In the present invention, as shown in Figure 8, the larger the tilt angle of the terminal support 20a, the longer the radius R2 of the auxiliary mountain side support rope 66, and therefore the amount of slip (amount of tension reduction) between the auxiliary mountain side support rope 66 and the auxiliary buffer device 65 increases.

[0060] That is, as the terminal support 20a tilts due to the influence of the tilt angle of the terminal support 20a, the amount of slippage between the auxiliary mountain side tie rope 66 and the auxiliary buffer 65 per tilt angle of the terminal support 20a increases. Therefore, the more the terminal support 20a falls, the greater the tilting resistance provided by the auxiliary buffer mechanism becomes, making it more difficult for the terminal support 20a to fall. The above-mentioned buffering effect of the buffer 60 continues not only during the initial tilting of the terminal support 20a but also thereafter, so the auxiliary buffering mechanism provided in the terminal support 20a continues to perform its buffering function for a long period of time.

[0061] In the present invention, an auxiliary buffer mechanism with a simple configuration is provided on the terminal support 20a, so that when the terminal support 20a tilts, the auxiliary buffer mechanism performs a buffering function without relying on the mountain-side anchor. In other words, when the terminal support 20a tilts, not only do the two support ropes with buffers 60 (mountain side support rope 61 and lateral support rope 63) exert a buffering effect, but the auxiliary mountain side support rope 66 with auxiliary buffer 65 also exerts a buffering effect. This significantly improves the energy absorption performance of the entire impact absorbing fence. In experiments, it was possible to increase the energy absorption capacity of the impact absorbing fence to 500-1000Kj. In particular, since the support reaction force of the auxiliary mountain side stay rope 66 is required from the base plate 24, there is no need to connect it to the mountain side anchor 11. Therefore, there is no need to install new mountain side anchors 11 or reinforce existing mountain side anchors to which mountain side backing ropes are connected. In this way, in the present invention, by simply providing a simple auxiliary shock-absorbing mechanism on the terminal support 20a, it is possible to significantly improve the shock-absorbing performance of the shock-absorbing fence while suppressing increases in the manufacturing costs of the shock-absorbing fence.

[0062] [Other Examples] The above has described a configuration in which an auxiliary shock absorbing mechanism (a combination of an auxiliary mountain side brace rope 66, a mooring shaft 28, and an auxiliary shock absorber 65) is added to the terminal support 20a, but the auxiliary shock absorbing mechanism may also be added to the intermediate support 20b. The function and effect of the auxiliary shock absorbing mechanism have already been described, so a detailed explanation will be omitted. [Explanation of symbols]

[0063] 10. Slope 11 Mountain side anchor 12. Anchor bolt 13 Lateral anchor 20...post 20a Terminal support 20b...Intermediate support 21. Support body 21a...Through hole 22. Connecting element 23...Connection piece 24...Spindle 25···Base plate 26... Implantation board 27...standing piece 28...Mooring shaft 30 Connector 31. Top rope 31a···Excess length of upper rope 32 Lower end rope 32a···Excess length of bottom rope 33 Vertical rope 34. Spacing rope 40...Protective net 41 Ring only 42. Wire mesh 50...Buffer 51...Holding plate 52 Fastening bolt 53 Nut 60...Buffer 61 Mountain side retaining rope 62 Mountain side positioning rope 63 Side support rope 64 Side positioning rope 65...Auxiliary shock absorber 66 Auxiliary mountain side support rope

Claims

1. An impact absorbing fence comprising a plurality of tiltable support posts erected at intervals and a protective net stretched across a plurality of spans of the support posts, The support pillar is tiltably erected via a support shaft on a base plate fixed to the ground, The support column is provided with an auxiliary shock absorber mechanism; The auxiliary buffer mechanism includes an auxiliary mountain-side support rope arranged along the longitudinal direction of the support pillar, a mooring shaft provided on the base plate at a distance from the support shaft toward the slope mountain side, for mooring the free end of the auxiliary mountain side stay rope; The base plate is provided with one or more auxiliary buffers spaced apart from the mooring shaft toward the mountain side of the slope, and which hold the free end of the auxiliary mountain side stay rope. When the support pillar tilts around the support shaft, the tension of the auxiliary mountain side stay rope increases, and the tension of the auxiliary mountain side stay rope is supported by the base plate. Shock absorbing fence.

2. 2. The impact-absorbing fence according to claim 1, wherein when the tension in the auxiliary mountain-side back rope exceeds the slip tension of the auxiliary shock absorber, slip occurs between the auxiliary mountain-side back rope and the auxiliary shock absorber, thereby reducing the tension in the auxiliary mountain-side back rope.

3. 2. The impact absorbing fence according to claim 1, wherein the support pole provided with the auxiliary shock absorbing mechanism is a terminal support pole.

4. 2. An impact-absorbing fence as set forth in claim 1, characterized in that a plurality of upper ropes, each having an independent shock-absorbing function for each span of the support pillar, are linked and laid horizontally between the heads of adjacent support pillars, a plurality of lower ropes, each having an independent shock-absorbing function for each span of the support pillar, are linked and laid horizontally between the bottom parts of adjacent support pillars, friction-sliding shock absorbers are installed near both ends of the upper and lower ropes, excess rope length is formed outside the shock absorbers, and when tension above a certain level is applied to the upper and lower ropes, sliding occurs between the ropes and the shock absorbers, thereby attenuating the tension.

5. 6. The impact-absorbing fence according to claim 5, wherein the upper and lower edges of the protective net are laterally movable and moored to the upper ropes and lower ropes via connectors, and the left and right sides of the protective net are attached to terminal posts.

6. 2. The impact-absorbing fence according to claim 1, wherein the protective net is a belt-like net formed by linking a plurality of ring units in a chain to form a net.

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