JP7540803B1 - Shock Absorbing Fence - Google Patents

Abstract

[Problem] To provide a high-performance shock absorbing fence while avoiding a significant increase in costs. [Solution] This shock absorbing fence has posts 20 tiltably erected on a base plate 25 fixed to the ground 10 via support shafts 24, and the heads of the posts 20 are connected to mountain side anchors by mountain side tie ropes with shock absorbers, the posts 20 are equipped with an auxiliary shock absorber mechanism, which includes an auxiliary mountain side tie rope 66 routed along the length of the posts 20, a mooring shaft 28 installed on the base plate 25 at a distance from the support shafts 24 on the slope side and mooring the free end of the auxiliary mountain side tie rope, and an auxiliary shock absorber 65 installed on the base plate 25 at a distance from the mooring shaft 28 on the slope side, and is configured such that when the posts 20 tilt around the support shafts 24, the tension of 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 Figure] Figure 7A

Description

The present invention relates to an impact absorbing fence that captures falling objects such as falling rocks and collapsed soil.

A typical shock absorbing fence is equipped with at least several posts (terminal posts and intermediate posts) erected at a specified distance apart, and a protective net stretched horizontally between adjacent posts, and absorbs the kinetic energy of falling objects such as falling rocks through the flexural deformation of the protective net and the bending strength of the posts.

Patent Document 1 discloses an impact absorbing fence in which multiple rope materials are laid horizontally between adjacent posts with shock absorbers provided near the ends of each rope material, thereby improving the energy absorption performance of the protective net formed on a span-by-span basis.
Patent documents 2 and 3 disclose providing a mountain side anchor on the mountain slope, stretching a mountain side backing rope between the mountain side anchor and the head of the pillar, and interposing a shock absorbing device between the mountain side backing rope and the mountain side anchor, so that when an impact is received and the pillar deforms towards the valley side of the slope, the shock absorbing device exerts a damping effect.

JP 2000-273828 A JP 2007-32032 A JP 2009-185514 A

The above-mentioned shock absorbing fence has a simplified structure in order to keep costs down.
Therefore, the energy absorption performance of the shock absorbing fence was limited to about 300 Kj.
In order to increase the energy absorption performance to 500 to 1000 Kj, not only will new improvements be necessary, but a significant increase in costs is also expected.

The present invention was made in consideration of the above points, and aims to provide a high-performance impact absorbing fence while avoiding a significant increase in costs.

The present invention provides an impact absorbing fence comprising a number of tiltable pillars set up at intervals and a protective net stretched across a number of spans of the pillars, the pillars being set up so as to be tiltable via support shafts on a base plate fixed to the ground, the pillars being equipped with an auxiliary shock absorbing mechanism comprising an auxiliary mountain side tie rope routed along the longitudinal direction of the pillar, a mooring shaft attached to the base plate and spaced from the support shaft on 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 absorbing devices attached to the base plate and spaced from the mooring shaft on the mountain side of the slope and for holding the free end of the auxiliary mountain side tie rope, the tension in the auxiliary mountain side tie rope increases when the pillar tilts around the support shaft 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 backing rope exceeds the slip tension of the auxiliary buffer device, slip occurs between the auxiliary mountain side backing rope and the auxiliary buffer device, thereby reducing a portion of the tension generated in the auxiliary mountain side backing 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 cushioning 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 cushioning function for each span of the support column, are linked and laid horizontally between the lower parts of adjacent support columns, and friction sliding type cushioning devices are installed near both ends of the upper and lower ropes, with excess rope length formed outside the cushioning devices, and when tension above a certain level is applied to the upper and lower ropes, sliding occurs between the ropes and the cushioning devices, thereby attenuating the tension.
In another form of the present invention, the upper and lower edges of the protective net are laterally movable and tethered to the upper ropes and lower ropes via connectors, and the left and right sides of the protective net are attached to terminal posts.
In another embodiment of the present invention, the protective net is a belt-shaped net formed by linking a plurality of ring units in a chain to form a net.

The present invention has at least one of the following advantages.
<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 any increase in the manufacturing costs of the shock absorbing fence.
<2> The amount of slip (amount of tension reduction) between the auxiliary mountain side brace rope and the auxiliary shock absorber increases per tilt angle of the support (terminal support), so the more the support falls, the greater the tilt resistance provided by the auxiliary shock absorber mechanism.
<3> The cushioning effect of the auxiliary cushioning mechanism occurs not only in the initial stage of the support pillar tilting, but also continues thereafter, so that the cushioning function is exerted for a longer period of time, thereby improving the cushioning 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 shock absorber.
This eliminates the need to install additional mountain side anchors to support the auxiliary mountain side backing ropes or to connect them to a common mountain side anchor for both the mountain side backing ropes, thereby 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 pillar at a high location, the installation work for the auxiliary shock absorbers can be done safely and easily.

FIG. 1 is a front view of an impact absorbing fence according to the present invention with some parts omitted. Enlarged view of the terminal section of the impact absorbing fence with some parts omitted A perspective view of the support with the middle part omitted Exploded view of the lower part of the intermediate support and the base plate A perspective view of the connection between the lower part of the terminal support and the base plate Exploded view of shock absorber VI-VI cross-sectional view in FIG. Horizontal cross section of the connection between the lower part of the intermediate support and the base plate 1. Cross-sectional view taken along the line VII-VII in FIG. Horizontal cross section of the connection between the bottom of the terminal support and the base plate An explanatory diagram of the function of the auxiliary shock absorbing mechanism installed on the terminal support

The following describes an embodiment of the present invention with reference to the drawings.

<1> Overview of Impact Absorbing Fence Figures 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 independently erected between the heads and bottoms of adjacent posts 20 in span units, 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 has a total length that allows it to be hung horizontally across multiple spans.
The main components are described in detail below.

<2> Support Columns Referring to FIG. 3, the support columns 20 include terminal support columns 20a and intermediate support columns 20b, and have the same basic structure.
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 .

<2.1> Pillar body The 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 pillar body 21 has a plurality of through holes 21a for inserting the upper end rope 31, and the upper and lower parts of the pillar body 21 have a plurality of bracket-shaped connecting elements 22 protruding therefrom for connecting a plurality of stay rope materials.
The lower part of the support pillar body 21 is provided with a connecting piece 23 for rotatably connecting to a base plate 25 via a support shaft 24 .

<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 pillar body 21, and is fixed to the ground by a plurality of anchor bolts 12.
Regarding the base plate 25 exemplified in this embodiment, a pair of standing pieces 27, 27 are provided at a predetermined distance from each other on the central portion of the upper surface of the landing plate 26 of the base plate 25.
A plurality of shaft holes 27 a are formed in the pair of upright pieces 27 , 27 along the longitudinal direction of the upright pieces 27 .
The multiple shaft holes 27a are used to pass the support shaft 24, the mooring shaft 28, and the lower end rope 32 through.

The base plate 25 for the intermediate struts does not have a mooring shaft 28 (FIG. 6B), whereas the base plate 25 for the end struts 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.

<2.3> Pivot Support Structure of Pillar Body and Base Plate The pillar body 21 is pivotally supported via a support shaft 24 to be tiltable relative to the base plate 25 .
In this example, a configuration in which the connecting piece 23 of the pillar 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 will be described.

The support pillar body 21 can be tilted not only around the support shaft 24 in the inclination direction of the slope, but also in the direction intersecting the support shaft 24 (diagonally lateral to the slope).
To pivot the pillar body 21 in the intersecting direction of 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.

<3> Upper end rope and lower end rope As shown in FIG. 1, an upper end rope 31 is laid horizontally between the heads of adjacent posts 20, and a lower end rope 32 is laid horizontally 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.

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 each of the upper end rope 31 and the lower end rope 32 are held by the buffer 50 (Figure 3).

<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.

<3.2> Excess Length Portion Each of the upper end ropes 31 and the lower end ropes 32 forms an excess length portion 31a, 32a in the range extending outward from the buffer device 50.
These excess lengths 31 a, 32 a are the allowable slip (sliding) lengths of the upper end rope 31 and the lower end rope 32 .

<3.3> Buffer for upper and lower end ropes The buffer 50 is a device for reducing the tension of the ropes when tension above a certain level acts on each of the upper end ropes 31 and the lower end ropes 32.
The number of buffer devices 50 to be installed on each end rope 31, 32 can be selected appropriately.

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 clamped between a pair of clamping plates 51 exceeds the gripping force, each of the end ropes 31, 32 slips and damps the kinetic energy.

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

<5> Support ropes The support poles 20 (terminal poles 20a, intermediate poles 20b) have mountain side support ropes 61 stretched between the mountain side anchors 11 and the heads of the support poles 20 to prevent the poles 20 from tilting toward the valley side.
A buffer device 60 is installed at the end or middle of the mountain side support rope 61.

<5.1> Stay rope for intermediate support A mountain side stay 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).

<5.2> Stay rope for terminal support A mountain side stay 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, a side support rope 63 and a side positioning rope 64 are connected to the terminal support 20a (Figure 2).
The side support rope 63 connects the top of the terminal strut 20 a to the side anchor 13 , and the side positioning rope 64 connects the bottom of the terminal strut 20 a to the side anchor 13 .
Buffer devices 60 are also installed at the ends or middle of the side support ropes 63.

<5.3> Buffer for back ropes The buffer 60 is a friction sliding type buffer comprising a pair of clamping plates having half grooves capable of gripping the back ropes 61, 63, and a plurality of fastening bolts and nuts capable of fastening the pair of clamping plates. When tension above a certain level acts on the mountain side back rope 61 or the lateral back rope 63, it allows sliding to reduce the tension of each back rope 61, 62.
As the friction sliding type shock absorber 60, for example, the shock absorber device described in Japanese Patent No. 6925674 can be used.

<6> Protective net In this example, the protective net 40 is described as being made of a mesh-like structure formed by linking together a number of individual rings 41 in a chain-like manner, but the protective net 40 may also be made of a known rope net.

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 such as a steel wire or a wire into a circular shape.
The diameter of the ring unit 41 can be appropriately selected, but in practice it is set to a size of about 30 to 50 cm.

<6.1> Total Length of Protection Net The protection 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.

<6.2> Installation position of the protection net on the support pillars The protection net 40 is disposed on the downstream side (slope valley side) of the support pillars 20.

<6.3> Means for attaching the protective net The protective net 40 is attached by anchoring its upper and lower edges to the upper and lower parts of multiple 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 protective net 40 and the intermediate support 20b, the upper and lower edges of the protective net 40 are anchored to the upper and lower parts of the intermediate support 20b.

The left and right sides of the protective net 40 are anchored to separate vertical ropes 33 that are installed along the terminal posts 20a via connectors 30 such as shackles.

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 necessary. 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.

<7> Auxiliary shock absorbing mechanism added to the terminal pillar As described above, the mountain side support rope 61 and the side support rope 63 are connected to the upper part of the terminal pillar 20a.

Description will be made with reference to Figures 4B, 7A and 7B.
In the present invention, an auxiliary shock absorbing mechanism is added to further improve the shock absorbing performance of the shock absorbing fence.
The auxiliary buffer mechanism comprises an auxiliary mountain side backing 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.

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

<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 device 65 is a manual friction buffer device that grips the auxiliary mountain side backing rope 66 by receiving a reaction force from the base plate 25, and when the tension generated in the auxiliary mountain side backing rope 66 exceeds a certain value (buffer device 65), it allows the auxiliary mountain side backing rope 66 to slide.
The auxiliary shock absorber 65 is configured, for example, by a combination of a pair of clamping plates 65a, 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 may be substituted with the shock absorber 50 already described.

In this example, a form in which the free end of the auxiliary mountain side backing rope 66 is held by a single auxiliary buffer device 65 is described, but multiple auxiliary buffer devices 65 may be arranged in series on the free end of the auxiliary mountain side backing 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 .

<7.3> Mooring Shaft A mooring shaft 28 is provided horizontally at the mountain end of the upright pieces 27, 27 erected on the base plate 25.
The mooring shaft 28 is a guide member at the bottom of the pillar body 21 for bending the lower part of the auxiliary mountain side back rope 66 at approximately a right angle and sliding it.
On each of the upright pieces 27, 27, the support shaft 24, the mooring shaft 28, and the auxiliary shock absorber 65 are positioned 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 provided in the upright pieces 27 , 27 .

<7.4> Support Member for Auxiliary Shock Absorber The auxiliary shock absorber 65 is disposed on the mountain side surfaces of the upright pieces 27, 27 and 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 backing rope 66 is obtained from the base plate 25.

<7.5> Reason for obtaining the reaction force of the auxiliary mountain side backing rope from the base plate It is also possible to obtain the supporting force of the auxiliary mountain side backing rope 66 from the mountain side anchor 11.
If the free end of the auxiliary mountain side backing rope 66 is moored to the mountain side anchor 11 and the reaction force of the auxiliary mountain side backing rope 66 is generated by the mountain side anchor 11, installing the additional mountain side anchor 11 requires cost and labor.
Furthermore, if the supporting force of the auxiliary mountain side backing rope 66 is required to be provided by the mountain side anchor 11 which is also used for the mountain side backing rope 66, the mountain side anchor 11 must be constructed to be large, which would result in a large burden in terms of cost and construction.

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 a mooring shaft and an auxiliary shock absorber 65.
By configuring it in this manner, the cushioning effect of the auxiliary cushioning device 65 can be exerted without relying on the mountain side anchor 11 for the reaction force of the auxiliary mountain side back rope 66.

<7.6> Positional relationship between the tilt center of the pillar and the tilt center of the auxiliary mountain side stay rope This will be explained with reference to Figure 8. The pillar 20 (terminal pillar 20a) tilts (pivots) with a radius _R1 around the support axis 24 toward the valley side of the slope.
The auxiliary mountain side stay rope 66 connected to the head of the support pillar 20 (terminal support pillar 20a) tilts (rotates) toward the slope valley side with a radius _R2 centered on the mooring axis 28 in response to the tilt of the support pillar 20.
The radius _R1 of the pillar 20 is unaffected by the inclination angle of the pillar 20 and remains unchanged, but the radius _R2 of the auxiliary mountain side bracing rope 66 becomes longer according to the inclination angle of the pillar 20.

Regarding the positional relationship between the tilt center of the support pillar 20 and the tilt center of the auxiliary mountain side backing rope 66, the tilt center (mooring axis 28) of the auxiliary mountain side backing 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 mountain side.
This is because the auxiliary shock absorber 65 exerts a shock absorbing effect when the terminal support 20a tilts.

Since the tilt center of the auxiliary mountain side support rope 66 is eccentric and away from the tilt center of the terminal support 20a, the tension of the auxiliary mountain side support rope 66 gradually increases in response to the tilt of the support 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 back rope 66 centered on the mooring axis 28, and the tension acting on the auxiliary mountain side back rope 66 gradually increases.
The radius difference G when the support 20 is tilted, i.e., the amount of slippage of the auxiliary mountain side back rope 66, is proportional to the distance between the two tilt centers (eccentric distance).

In short, the mooring shaft 28 should be arranged on the base plate 25 so that the tension in the auxiliary mountain side bracing rope 66 increases when the pillar body 21 tilts around the support shaft 24.

<7.7> Regarding the installation position of the auxiliary shock absorber With regard to the arrangement structure of the auxiliary mountain side backing rope 66, it is also possible to fix the tip of the auxiliary mountain side backing rope 66 to the base plate 25 side and provide the auxiliary shock absorber 65 on the head side of the pillar main body 21.
If the auxiliary shock absorber 65 is provided on the head side of the pillar body 21, not only will the task of attaching the heavy auxiliary shock absorber 65 to a high place be dangerous and difficult, but the excess length 66a of the auxiliary mountain side bracing rope 66 will hang down on the head side of the pillar body 21, marring the scenery.
If the auxiliary shock absorber 65 is provided on the lower side of the base plate 25, such a drawback can be avoided and the auxiliary shock absorber 65 can be easily installed in a safe working environment.

[Damping effect of impact absorbing fence]
The following describes the damping effect when a falling object such as a rock strikes an impact absorbing fence.

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

<2> Damping effect of the upper and lower end ropes and buffer devices As the protective net 40 deforms, the upper end rope 31 and the lower end rope 32 stretched across the striking 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 device 50), slip occurs between each of the upper and lower end ropes 31, 32 and the buffer device 50, reducing part of the tension generated in the ropes 31, 32.

<3> Damping effect of mountain side bracing ropes and shock absorbers As the protective net 40 deforms, not only do the intermediate supports 20b tilt toward the valley side of the slope, but the intermediate supports 20b also tilt toward 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 of the mountain side backup rope 61 exceeds the slip tension (the gripping force of the rope by the buffer device 60), slip occurs between the mountain side backup rope 61 and the buffer device 60, reducing part of the tension generated in the mountain side backup rope 61.

<4> Transmission of Impact Load The impact load of a collapsed object acting on a part of the impact surface of the protective net 40 is transmitted through the protective 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 multiple spacing ropes 34.

<5> Damping effect of lateral bracing ropes and buffer devices When an impact load is transmitted to the terminal posts 20a located at both ends of the impact absorbing fence, the tension of the lateral bracing ropes 63 increases. When the tension of the lateral bracing ropes 63 exceeds the slip tension (the gripping force of the rope by the buffer devices 60), slip occurs between the lateral bracing ropes 63 and the buffer devices 60, which dampens part of the tension generated in the lateral bracing ropes 63.

<6> Damping Action by Auxiliary Buffer Mechanism When the terminal strut 20a tilts toward the slope valley side or in the approaching direction of the strut, the auxiliary buffer mechanism provided in the terminal strut 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.

When the tension of the auxiliary mountain side back rope 66 exceeds the slip tension (the gripping force of the rope by the auxiliary shock absorber 65), slip occurs between the auxiliary mountain side back rope 66 and the auxiliary shock absorber 65, reducing part of the tension generated in the auxiliary mountain side back rope 66.

The present invention does not cause even slippage between the auxiliary mountain side brace rope 66 and the auxiliary buffer device 65 without being affected by the tilt angle of the terminal support 20a.

In the present invention, as shown in FIG. 8, the larger the inclination angle of the terminal support 20a, the longer the radius _R2 of the auxiliary mountain side back rope 66, and therefore the amount of slip (amount of tension reduction) between the auxiliary mountain side back rope 66 and the auxiliary buffer 65 increases.

That is, as the terminal pole 20a tilts due to the influence of the tilt angle of the terminal pole 20a, the amount of slip between the auxiliary mountain side tie rope 66 and the auxiliary buffer device 65 per tilt angle of the terminal pole 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 cushioning effect of the cushioning device 60 continues not only during the initial tilting of the terminal pole 20a but also thereafter, so that the auxiliary cushioning mechanism provided in the terminal pole 20a continues to exert its cushioning function for a long period of time.

In the present invention, the terminal column 20a is provided with an auxiliary shock absorbing mechanism of simple construction, so that when the terminal column 20a tilts, the auxiliary shock absorbing mechanism exerts a shock absorbing function without depending on the mountain side anchor.
In other words, when the terminal support 20a tilts, not only do the two backing ropes with cushioning devices 60 (mountain side backing rope 61, lateral backing rope 63) provide a cushioning effect, but the auxiliary mountain side backing rope 66 with auxiliary cushioning device 65 also provides a cushioning effect.
This significantly improves the energy absorption performance of the entire impact absorbing fence.
In experiments, it was possible to increase the energy absorption performance of the impact absorbing fence to 500-1000 Kj.
In particular, since the supporting reaction force of the auxiliary mountain side stay rope 66 is required in the base plate 24, there is no need to connect it to the mountain side anchor 11.
Therefore, there is no need to newly install additional mountain side anchors 11 or reinforce existing mountain side anchors to which mountain side backup ropes are connected.
In this way, in the present invention, by simply providing a simple auxiliary cushioning mechanism on the terminal support 20a, it is possible to significantly improve the cushioning performance of the impact absorbing fence while suppressing any increase in the manufacturing costs of the impact absorbing fence.

[Other embodiments]
The above describes a form in which an auxiliary shock absorbing mechanism (a combination of an auxiliary mountain side bracing rope 66, a mooring shaft 28, and an auxiliary shock absorbing device 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 been described above, so a detailed description thereof will be omitted.

10...Slope 11...Mountain side anchor 12...Anchor bolt 13...Side anchor 20...Support 20a...Terminal support 20b...Intermediate support 21...Support body 21a...Through hole 22...Connecting element 23...Connecting piece 24...Support shaft 25...Base plate 26...Landing plate 27...Upright piece 28...Mooring shaft 30...Connector 31...Upper end rope 31a...Excess length of upper end rope 32... Lower end rope 32a...excess length of lower end rope 33...vertical rope 34...spacing rope 40...protective net 41...single ring 42...wire mesh 50...shock absorber 51...clamping plate 52...fastening bolt 53...nut 60...shock absorber 61...mountain side support 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 (6)

An impact absorbing fence comprising a plurality of tiltable pillars erected at intervals and a protective net stretched across a plurality of spans of the pillars,
The support pillar is tiltably supported on a base plate fixed to the ground via a support shaft,
The support column is provided with an auxiliary shock absorber mechanism;
The auxiliary shock absorbing mechanism includes an auxiliary mountain side bracing 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 to the slope mountain side and for mooring a 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 configured to 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 bracing rope increases, and the tension of the auxiliary mountain side bracing rope is supported by the base plate.
Shock absorbing fence. The shock absorbing fence of claim 1, characterized in that when the tension of the auxiliary mountain side bracing rope exceeds the slip tension of the auxiliary shock absorber, slip occurs between the auxiliary mountain side bracing rope and the auxiliary shock absorber, thereby reducing the tension generated in the auxiliary mountain side bracing rope. The shock absorbing fence according to claim 1, characterized in that the support equipped with the auxiliary shock absorbing mechanism is a terminal support. The shock absorbing fence according to claim 1, characterized in that multiple upper ropes, each of which has an independent shock absorbing function for each span of the support, are linked and laid horizontally between the heads of adjacent support columns, multiple lower ropes, each of which has an independent shock absorbing function for each span of the support columns, are linked and laid horizontally between the lower parts of adjacent support columns, the upper and lower ropes are provided with friction sliding type shock absorbers near both ends of the upper and lower ropes, excess rope 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 to attenuate the tension. 5. The impact absorbing fence according to claim 4, wherein the upper and lower edges of the protective net are laterally movable and tethered to the upper ropes and lower ropes via connectors, and the left and right sides of the protective net are attached to terminal posts. The shock absorbing fence according to claim 1, characterized in that the protective net is a belt-shaped net formed by linking multiple ring units in a chain to form a net.

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