WO2021181934A1 - Shock absorption unit and rock fall prevention system - Google Patents

Abstract

A shock absorption unit (10, 20, 100, 200) for absorbing shock has a compressible spring (12, 22, 120, 220) and a securing member (14, 24, 152, 230) for securing the spring. When the magnitude of the shock applied to the shock absorption unit (10, 20, 100, 200) is greater than a prescribed threshold value, the securing member (14, 24, 152, 230) fractures, whereby the shock applied to the shock absorption unit (10, 20, 100, 200) is absorbed.

Description

Shock absorption unit and rockfall prevention system

The present invention relates to a shock absorbing unit for absorbing shocks and a rockfall prevention system installed on a mountain slope or the like using such a shock absorbing unit.

Conventionally, in a rockfall protection fence installed on a mountain slope or the like to catch a rockfall, the impact when the rockfall is received by the rockfall protection fence is absorbed by a shock absorbing unit. More specifically, as a rockfall protection fence using such a shock absorbing unit, the one disclosed in FIG. 1 of Japanese Patent No. 5978022 is known.

The fall guard fence disclosed in FIG. 1 of Japanese Patent No. 5978022 includes a strut arranged on a slope at a predetermined interval and a mountain side wire stretched between the upper end of the strut and the mountain side slope. It has a ring-type net, etc., which is stretched between the columns to catch falling rocks. In addition, by allowing deformation (elongation) of the mountain side wire or the like when a rock fall is received by the ring type net, a part of the impact applied to the mountain side wire or the like due to the elongation of the mountain side wire is absorbed. It has become. More specifically, a part of the mountain side wire is wound once so as to overlap in the radial direction of the mountain side wire to form an annular portion, and a tightening member arranged in the overlapped portion is crimped to form an annular portion. The part is fixed. Then, when an impact is applied, the size of the ring of the annular portion becomes smaller, so that a part of the impact when receiving the falling rock is absorbed by the frictional force acting between the mountain side wire and the tightening member. It has become so.

However, the conventional shock absorbing unit as disclosed in Japanese Patent No. 5978022 absorbs the shock applied to the wire by allowing the wire to stretch, and the magnitude of the shock given in the above configuration is large. The wire can be stretched even when the size is small. As described above, since the wire is easily stretched even with a small impact, there is a problem that it is necessary to perform maintenance of the impact absorbing unit at relatively short intervals.

The present invention has been made in consideration of such a point, and is an impact absorbing unit capable of absorbing an impact by breaking a fixing member only when an impact larger than a predetermined threshold value is applied. And it is an object of the present invention to provide a rockfall prevention system using such a shock absorbing unit.

The shock absorbing unit of the present invention is a shock absorbing unit for absorbing a shock, and has a stretchable spring and a fixing member for fixing the spring, and is added to the shock absorbing unit. It is characterized in that the fixing member breaks when the magnitude of the impact is larger than a predetermined threshold value.

According to such a shock absorbing unit, the fixing member breaks and the spring expands and contracts only when an impact larger than a predetermined threshold value is applied. Therefore, when the fixing member breaks, the impact is applied. It can be made to absorb.

In the shock absorbing unit of the present invention, the spring may be a push spring, and the fixing member may fix the spring in a compressed state along the longitudinal direction.

Alternatively, the spring may be a pull spring.

In the shock absorbing unit of the present invention, the fixing member is provided with a broken portion.
When the magnitude of the impact applied to the impact absorbing unit is larger than a predetermined threshold value, the fixing member may be fractured along the fractured portion.

Further, in the shock absorbing unit of the present invention, the fixing member is arranged around the spring, and the fixing member is fixed inside the fixing member so as not to allow the spring to stretch when the fixing member breaks. A portion and an open portion that allows the spring to stretch when the fixing member is broken may be formed.

Further, the fixing member includes a first accommodating portion for accommodating a part of the spring inside, a second accommodating portion for accommodating a part of the spring inside, and the first accommodating portion. It has a maintenance portion for maintaining the second accommodating portion so as not to move relatively, and when the magnitude of the impact applied to the shock absorbing unit is larger than a predetermined threshold value, the maintenance portion is provided. The portion may be broken.

In this case, inside the first accommodating portion and the second accommodating portion of the fixing member, the fixing portion that does not allow the extension of the spring when the maintenance portion is broken and the maintenance portion are broken. Occasionally, an open portion that allows the extension of the spring may be formed.

In the shock absorbing unit of the present invention, the maintenance portion of the fixing member includes a rod-shaped member arranged inside the spring, and the magnitude of the shock applied to the shock absorbing unit is equal to or less than a predetermined threshold value. The rod-shaped member may be broken when the size is large.

Further, in the shock absorbing unit of the present invention, the fixing member is arranged inside the spring, and the fixing member is fixed outside the fixing member so as not to allow the spring to stretch when the fixing member breaks. A portion and an open portion that allows the spring to stretch when the fixing member is broken may be formed.

Even if the shock absorbing unit of the present invention further includes a protective member arranged around the spring and a sealing member arranged at a position in contact with the protective member and liquid-tightly sealing the spring. good.

The rock fall prevention system of the present invention includes a plurality of columns arranged on a slope at predetermined intervals, a falling object receiving member stretched on each of the columns and receiving a falling object falling along the slope, and each of them. It has a wire body stretched between the support column and the slope on the mountain side, a shock absorbing unit connected to the wire body, a stretchable spring, and a fixing member for fixing the spring. It is characterized by including a shock absorbing unit in which the fixing member breaks when the magnitude of the shock applied to the shock absorbing unit is larger than a predetermined threshold value.

According to such a rockfall prevention system, maintenance can be performed by using a shock absorbing unit that absorbs the shock by breaking the fixed part and expanding and contracting the spring only when an impact larger than a predetermined threshold is applied. The time and effort can be reduced.

In the rock fall prevention system of the present invention, as the impact unit, a plurality of types having different thresholds of the magnitude of the impact at which the fixing member breaks when an impact is applied to the impact absorbing unit are lined up in series. May be used.

It is a perspective view which shows the structure of the shock absorption unit by embodiment of this invention. It is a top view which shows the structure of the spring in the compressed state provided in the shock absorbing unit shown in FIG. It is sectional drawing which shows the structure of the fixing member provided in the shock absorbing unit shown in FIG. It is explanatory drawing for demonstrating the structure of the fixing member of the shock absorption unit shown in FIG. It is explanatory drawing for demonstrating the structure when the fixing member of the shock absorbing unit shown in FIG. 1 and the like breaks. It is explanatory drawing which shows the structure of another example of the shock absorption unit by this embodiment. It is explanatory drawing for demonstrating the structure of the fixing member of the shock absorbing unit shown in FIG. It is explanatory drawing for demonstrating the structure when the fixing member of the shock absorbing unit shown in FIG. 6 is broken. It is explanatory drawing which shows the structure of still another example of the shock absorption unit by this embodiment. It is a top view which shows the structure of the attachment part of the shock absorption unit shown in FIG. It is sectional drawing which shows the structure of the fixing member and the inner housing of the shock absorbing unit shown in FIG. 9 and the like. It is explanatory drawing which shows the structure when the attachment part, the fixing member and the inner housing of the shock absorbing unit shown in FIG. 9 and the like are assembled. It is explanatory drawing for demonstrating the structure when the fixing member of the shock absorbing unit shown in FIG. 9 and the like breaks. It is explanatory drawing which shows the structure of still another example of the shock absorption unit by this embodiment. It is a top view which shows the structure of the fixing member of the shock absorption unit shown in FIG. 14 and the like. It is sectional drawing which shows the structure of the protection member of the shock absorption unit shown in FIG. It is explanatory drawing for demonstrating the structure when the fixing member of the shock absorbing unit shown in FIG. 14 and the like breaks. It is a perspective view which shows the structure of the shock absorption unit by the prior art. FIG. 5 is a perspective view schematically showing a configuration of a rockfall prevention system using the shock absorbing unit shown in FIG. 1 and the like. It is a side view which shows schematic structure of the rockfall prevention system shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 20 are views for explaining a shock absorbing unit and a rockfall prevention system according to the present embodiment. Of these, FIG. 1 is a configuration diagram showing a configuration of a shock absorbing unit according to the present embodiment, and FIGS. 2 and 3 are a top view and a fixed view showing a configuration of a spring of the shock absorbing unit shown in FIG. 1, respectively. It is sectional drawing which shows the structure of a member. 4 and 5 are explanatory views for explaining the configurations of the fixing member of the shock absorbing unit shown in FIG. 1 before and after the fracture, respectively. 6 to 8 are explanatory views for explaining the configuration of another example of the shock absorbing unit according to the present embodiment, respectively. 9 to 13 are a top view, a cross-sectional view, and an explanatory view for explaining the configuration of still another example of the shock absorbing unit according to the present embodiment, respectively. 14 to 17 are a top view, a cross-sectional view, and an explanatory view for explaining the configuration of still another example of the shock absorbing unit according to the present embodiment, respectively. Further, FIG. 18 is a perspective view showing a configuration of a shock absorbing unit according to the prior art. Further, FIG. 19 is a perspective view schematically showing the configuration of the rockfall prevention system using the shock absorbing unit shown in FIG. 1 and the like, and FIG. 20 schematically shows the configuration of the rockfall prevention system shown in FIG. It is a side view. In order to make it easier to understand the configuration when the fixing member is broken and the spring is extended, a cross-sectional view is shown for the fixing member, and a top view is shown for the spring and the mounting member in FIGS. 4 to 8. ing. Further, although details will be described later, in FIGS. 9 and 14, for the purpose of facilitating the understanding of the configuration, further examples of the shock absorbing unit are described by combining a cross-sectional view and a top view. .. Further, in FIG. 20, a falling object falling along the slope is indicated by reference numeral D.

As shown in FIGS. 1 to 5, the shock absorbing unit 10 of the present embodiment is arranged around the expandable spring 12 and the spring 12, and is fixed to fix the spring 12 so as not to expand and contract. It has a member 14. Then, when an impact larger than a predetermined threshold value is applied to the shock absorbing unit 10, the fixing member 14 breaks, so that the shock applied to the shock absorbing unit 10 is absorbed. Further, by allowing the spring 12 to expand and contract when the fixing member 14 breaks, the impact applied to the impact absorbing unit 10 is further absorbed. Specifically, the fixing member 14 is provided with a breaking portion 18 described later, and when the magnitude of the impact applied to the shock absorbing unit 10 is larger than a predetermined threshold value, the fixing member 14 is provided on the breaking portion 18. It is designed to break along (see FIG. 5).

Further, the spring 12 is composed of a push spring having a substantially cylindrical shape, and the spring 12 can expand and contract along the longitudinal direction (that is, along the left-right direction in FIG. 2). Here, the push spring generally means that each coil portion is wound so that a gap exists between each coil forming the spring portion (that is, the spring portion can be compressed along the longitudinal direction). It is a spring. In the example shown in FIG. 1 and the like, the spring 12 is fixed by the fixing member 14 in a state of being compressed along the longitudinal direction so that the coil portions are in close contact with each other. Further, hooks 13 having a substantially S shape are provided at both ends of the spring 12 as mounting members. Specifically, the spring 12 is formed so that the outer diameter becomes smaller in the vicinity of both ends of the spring 12, and one end of the substantially S-shaped hook 13 is installed so as to be located inside the spring 12. ing. Then, each hook 13 allows the shock absorbing unit 10 to be attached to the wire body 330 of the rockfall prevention system 300, which will be described later (see FIG. 20). Further, the spring 12 is formed of a hard steel wire, a piano wire, a stainless steel wire, or the like.

As shown in FIG. 3, the fixing member 14 of the shock absorbing unit 10 is composed of a sleeve having a substantially cylindrical shape, and a fixing portion 15 and an open portion 16 are formed inside the fixing member 14, respectively. .. Specifically, the fixing portion 15 is provided on both end sides of the fixing member 14, and is configured so as not to allow the spring 12 to stretch when the fixing member 14 breaks along the breaking portion 18. .. More specifically, as shown in FIGS. 4 and 5, the fixed portion 15 has a shape along the contour of the spring 12, and the inner surface of the fixed portion 15 and the outer surface of the spring 12 are in contact with each other. Have been placed. Therefore, even when the hooks 13 of the shock absorbing unit 10 are pulled away from each other and the fixing member 14 breaks along the broken portion 18, the portion of the spring 12 in contact with the fixed portion 15 is shown in FIG. It does not extend from the state shown in 4. On the other hand, the open portion 16 is provided in the central portion of the fixing member 14, and is configured to allow the spring 12 to stretch when the fixing member 14 breaks along the breaking portion 18. More specifically, as shown in FIG. 4 and the like, the open portion 16 has a shape different from the contour of the spring 12, and opens with the spring 12 when the spring 12 is housed inside the fixing member 14. It is designed so that it does not come into contact with the portion 16. Specifically, the open portion 16 of the fixing member 14 is composed of a substantially cylindrical portion having an inner diameter larger than the outer diameter of the spring 12.

As described above, the fixing member 14 is provided with a breaking portion 18, and the fixing member 14 is adapted to break along the breaking portion 18. Specifically, when an impact in a direction away from each other is applied to each hook 13 provided at both ends of the spring 12, if the magnitude of the impact is larger than a predetermined threshold value, the fixing member 14 is subjected to. It breaks along the broken portion 18. In the example shown in FIG. 1 and the like, the fractured portion 18 is a groove having a substantially V-shaped cross section (wedge shape). Further, the fractured portion 18 is formed in a substantially central portion of the cylindrical open portion 16 over the entire circumference along the circumferential direction.

Specifically, when an impact larger than a predetermined threshold value is applied to each hook 13 of the shock absorbing unit 10 in the state shown in FIG. 4, the fixing member 14 breaks along the broken portion 18 as shown in FIG. .. Due to the breakage of the fixing member 14, a part of the shock applied to the shock absorbing unit 10 is absorbed. Further, as described above, since the open portion 16 of the fixing member 14 is not in contact with the spring 12, the extension of the spring 12 is allowed when the fixing member 14 is broken. Further, when the extension of the spring 12 is allowed, the extension of the spring 12 further absorbs the impact applied to the impact absorbing unit 10. As described above, since the shock absorbing unit 10 absorbs the shock by breaking the fixing member 14 and expanding and contracting the spring 12, the shock absorbing unit 10 can absorb the shock more effectively as compared with the configuration of absorbing the shock by friction.

Further, by changing the shape of the fractured portion 18 formed on the fixing member 14, it is possible to adjust the threshold value of the magnitude of the impact when the fixing member 14 is fractured. For example, if the depth of the groove of the fractured portion 18 is made shallower from the state shown in FIG. 4, the fixing member 14 is less likely to fracture along the fractured portion 18, so that the threshold value of the magnitude of the impact when the fixing member 14 is fractured. Can be increased. On the other hand, if the depth of the groove of the fractured portion 18 is deepened from the state shown in FIG. 4, the fixing member 14 is likely to be fractured along the fractured portion 18, so that the threshold value of the magnitude of the impact when the fixing member 14 is fractured Can be made smaller. This makes it possible to manufacture a shock absorbing unit 10 that absorbs shocks of various sizes.

Further, the shape of the broken portion 18 is not limited to that shown in FIG. 4 and the like. The above-mentioned groove having a substantially V-shaped cross section may be formed only in a part of the fixing member 14 in the circumferential direction. Further, the shape of the cross section of the broken portion provided on the fixing member 14 may be a substantially U-shaped shape, a concave shape, a recessed shape, or the like. In other words, the fractured portion may have any shape as long as the portion of the fixing member 14 where the fractured portion 18 is formed has a lower strength than the other portions of the fixing member 14.

When the breaking portion 18 is formed over the entire circumference of the fixing member 14 in the circumferential direction and the cross section is substantially V-shaped, the breaking load of the fixing member 14 can be calculated by a known method. Therefore, the above-mentioned predetermined threshold value can be obtained by calculation, and thus the shock absorbing unit 10 having the desired predetermined threshold value can be easily designed. Further, even when the shape of the fractured portion 18 is complicated and the fractured load of the fixing member 14 cannot be easily calculated, the impact absorbing unit 10 having a desired threshold value is obtained by producing and evaluating a prototype. Can be produced.

Further, instead of adjusting the threshold value of the magnitude of impact when the fixing member 14 breaks by changing the shape of the broken portion 18, or in addition to changing the shape of the broken portion 18, the following The impact magnitude threshold may be adjusted by the method. Specifically, the threshold value of the magnitude of the impact when the fixing member 14 breaks may be adjusted by changing the material constituting the fixing member 14. As described above, when the materials are different, the threshold value of the magnitude of the impact when the fixing member 14 breaks can be adjusted even when the fixing member 14 is formed into substantially the same shape. Specifically, as the material of the fixing member 14, carbon steel, stainless steel, aluminum alloy, copper, brass, titanium, plastic, or the like can be used. For example, the threshold value of the impact magnitude when the fixing member 14 made of carbon steel breaks is larger than the threshold value of the impact magnitude when the fixing member 14 made of plastic breaks. Become.

Further, as another example of the shock absorbing unit 10 of the present embodiment, those shown in FIGS. 6 to 8 may be used. 6 to 8 are explanatory views for explaining the configuration of another example of the shock absorbing unit of the present invention, respectively. As described above, also in FIGS. 6 to 8, a cross-sectional view is shown for the fixing member, and a top view is shown for the spring and the mounting member.

The shock absorbing unit 20 shown in FIGS. 6 to 8 has a stretchable spring 22 and a fixing member 24 which is arranged around the spring 22 and for fixing the spring 22 so as not to stretch. .. Further, when a shock larger than a predetermined threshold value is applied to the shock absorbing unit 20, a part of the fixing member 24 (specifically, the knock pin 28a described later) breaks, so that the shock absorbing unit 20 is added to the shock absorbing unit 20. It is designed to absorb the impact.

Specifically, the spring 22 is composed of a push spring having a substantially cylindrical shape, and the spring 22 can expand and contract along the longitudinal direction (that is, along the left-right direction in FIG. 6). There is. In the example shown in FIG. 6 and the like, the spring 22 is fixed by the fixing member 24 in a state of being compressed along the longitudinal direction so that the coil portions are in close contact with each other. Further, as shown in FIG. 6 and the like, mounting members 23 are provided at both ends of the spring 22. Then, each mounting member 23 allows the shock absorbing unit 20 to be mounted on the wire body 330 of the rockfall prevention system 300, which will be described later (see FIG. 20). Further, the spring 22 is formed of a hard steel wire, a piano wire, a stainless steel wire, or the like.

As shown in FIG. 6 and the like, the fixing member 24 of the shock absorbing unit 20 is composed of a combination of a plurality of members. Specifically, the fixing member 24 includes a pair of tubular members 24a and 24b (that is, a first accommodating portion and a second accommodating portion) and a sleeve 24c arranged around the tubular members 24a and 24b. And knock pins 28a, 28b (that is, a maintenance portion). Further, the spring 22 is arranged inside the pair of tubular members 24a and 24b. In other words, a part of the spring 22 is housed inside one of the tubular members 24a, and a part of the spring 22 is also housed inside the other tubular member 24b. ing.

Further, the tubular members 24a and 24b are provided with substantially circular openings 27a and 27b, respectively. Further, the sleeve 24c is also provided with two substantially circular openings 27c, respectively. Then, the tubular members 24a, 24b and the sleeve 24c are installed so that the openings 27a and 27b and the openings 27c face each other. After that, the substantially cylindrical knock pin 28a is inserted into the respective openings 27a and 27c, and the substantially cylindrical knock pin 28b is inserted into the respective openings 27b and 27c. By the knock pins 28a and 28b as such a maintenance portion, the tubular members 24a and 24b are maintained so as not to move relatively. In this way, the shock absorbing unit 20 can be assembled.

Further, each of the tubular members 24a and 24b has a first outer diameter, and has a first portion on the side where the mounting member 23 is provided and a second outer diameter larger than the above first outer diameter. It is provided with a second portion having. Further, inside the first portions of the tubular members 24a and 24b, fixed portions 25a and 25b that do not allow the spring 22 to stretch when the knock pin 28a breaks are formed, respectively.

More specifically, as shown in FIG. 6 and the like, each of the fixed portions 25a and 25b has a shape along the contour of the spring 22, and the inner surface of each of the fixed portions 25a and 25b and the outer surface of the spring 22. Are placed in contact with each other. Therefore, even when the mounting members 23 of the shock absorbing unit 20 are pulled away from each other and the knock pin 28a breaks along the broken portion, the portion of the spring 22 that is in contact with the fixed portions 25a and 25b remains. It does not extend from the state shown in FIG. In this case, the broken portion is a portion near the portion of the knock pin 28a where the tubular member 24a and the sleeve 24c are in contact with each other. On the other hand, inside the second portions of the tubular members 24a and 24b, open portions 26a and 26b that allow the spring 22 to stretch when the knock pin 28a breaks are formed, respectively. More specifically, as shown in FIG. 7 and the like, the open portions 26a and 26b have a shape different from the contour of the spring 22. When the spring 22 is housed inside the tubular members 24a and 24b, the spring 22 and the open portions 26a and 26b do not come into contact with each other. Specifically, the open portions 26a and 26b of the tubular members 24a and 24b are composed of substantially cylindrical portions having an inner diameter larger than the outer diameter of the spring 22.

In the example shown in FIG. 6 and the like, the one in which the shear stress of the knock pin 28a on the right side is 5 KN and the shear stress of the knock pin 28b on the left side is 20 KN are used. Therefore, when an impact larger than a predetermined threshold value is applied to the impact absorbing unit 20, the knock pin 28a is first broken to allow the spring 22 to stretch (see FIG. 8). By breaking the knock pin 28a in this way, a part of the shock applied to the shock absorbing unit 20 is absorbed. As described above, the knock pin 28a is designed to break from the vicinity of the portion where the tubular member 24a and the sleeve 24c are in contact with each other, and this portion is fixed in the shock absorbing unit 20 shown in FIG. 6 or the like. Corresponds to the broken portion of the member 24.

Further, as described above, since the open portions 26a and 26b of the tubular members 24a and 24b are not in contact with the spring 22, the spring 22 is allowed to stretch when the knock pin 28a is broken. Further, when the extension of the spring 22 is allowed, the extension of the spring 22 further absorbs the impact applied to the impact absorbing unit 10. As described above, since the shock absorbing unit 20 absorbs the shock by breaking the knock pin 28a and expanding and contracting the spring 22, the shock absorbing unit 20 can absorb the shock more effectively as compared with the configuration of absorbing the shock by friction. Further, if a further impact is applied to the shock absorbing unit 20 after the knock pin 28a is broken, the knock pin 28b is also broken.

Further, although the example in which the shear stress of the knock pin 28a on the right side is 5 KN and the shear stress of the knock pin 28b on the left side is 20 KN is used, the present invention is not limited to such a configuration. Knock pins 28a and 28b having shear stresses different from those described above may be used, or knock pins 28a and 28b having substantially the same shear stress may be used. Even if the shock absorbing units 20 have substantially the same shape, by using the knock pins 28a and 28b having different configurations, the threshold value of the magnitude of the shock when the knock pins 28a and 28b of the shock absorbing unit 20 are broken is the threshold value. Can be adjusted. Specifically, by changing the material and diameter of the knock pins 28a and 28b, the threshold value of the impact magnitude when the knock pins 28a and 28b break can be adjusted.

The number of openings 27a and 27b provided in the tubular members 24a and 24b is not limited to one, and two or more openings 27a and 27b are provided in the tubular members 24a and 24b, respectively. You may be. In this case, the sleeve 24c is formed with the same number of openings 27c as the total number of the openings 27a, 27b provided in the tubular members 24a, 24b. In other words, the sleeve 24c is formed with the same number of openings 27c as the total number of openings 27a, 27b provided in the tubular members 24a, 24b. In addition, knock pins are arranged so as to penetrate the openings 27a, 27b, and 27c, respectively.

Further, as still another example of the shock absorbing unit 10 of the present embodiment, those shown in FIGS. 9 to 13 may be used. 9 to 13 are a top view, a cross-sectional view, and an explanatory view for explaining the configuration of still another example of the shock absorbing unit of the present invention, respectively. Here, FIGS. 10 and 11 are top views and cross-sectional views for explaining the configuration of still another example of the shock absorbing unit, respectively. Further, FIGS. 9, 12 and 13 are explanatory views depicting the shock absorbing unit by combining a cross-sectional view and a top view for the purpose of making the configuration easy to understand.

The shock absorbing unit 100 shown in FIGS. 9 to 13 has a stretchable spring 120 and a fixing member 130 arranged around the spring 120 so that the spring 120 does not stretch. .. Further, when an impact larger than a predetermined threshold value is applied to the shock absorbing unit 100, a part of the fixing member 130 (specifically, a rod-shaped member 152 described later) breaks, so that the shock absorbing unit 100 is added to the shock absorbing unit 100. It is designed to absorb the impact.

Specifically, the spring 120 is composed of a push spring having a substantially cylindrical shape, and the spring 120 can expand and contract along the longitudinal direction (that is, along the left-right direction in FIG. 9). There is. In the example shown in FIG. 9 and the like, the spring 120 is fixed by the fixing member 130 in a state of being compressed along the longitudinal direction so that the coil portions are in close contact with each other. Further, as shown in FIG. 9 and the like, mounting portions 110a and 110b are provided at both ends of the spring 120, respectively. Then, the shock absorbing unit 100 is attached to the wire main body 330 of the rockfall prevention system 300, which will be described later, by the attachment portions 110a and 110b (see FIG. 20). The spring 120 is made of a hard steel wire, a piano wire, a stainless steel wire, or the like.

As shown in FIG. 9 and the like, the fixing member 130 of the shock absorbing unit 100 is composed of a combination of a plurality of members. Specifically, the fixing member 130 includes a pair of tubular members 130a and 130b (that is, a first accommodating portion and a second accommodating portion) and an inner housing 140a installed inside a substantially cylindrical spring 120. , 140b and a maintenance portion 150. Further, the spring 120 is arranged inside the pair of tubular members 130a and 130b. More specifically, a part of the spring 120 is housed inside one tubular member 130a, and the rest of the spring 120 is housed inside the other tubular member 130b. In the present embodiment, the tubular members 130a and 130b and the inner housings 140a and 140b are respectively configured to come into contact with each other at a substantially central portion in the length direction of the spring 120. Then, such a state is maintained by the maintenance portion 150.

Next, a configuration in which the tubular members 130a and 130b are maintained so as not to move relatively by the maintenance portion 150 will be described with reference to FIGS. 9 to 12. The configurations of the mounting portions 110a and 110b, the tubular members 130a and 130b, and the inner housings 140a and 140b are substantially the same. Therefore, in the following, the configuration of one member (the member on the left side in FIG. 9) may be described in detail, and the configuration of the other member (member on the right side in FIG. 9) may be omitted.

The mounting portion 110a has a mounting portion 111a to which the wire body 330 of the rockfall prevention system 300, which will be described later, is mounted, an intermediate portion 114a, and a screw portion 116a on which a mounting portion such as a male screw is formed. Further, the intermediate portion 114a is provided between the mounting portion 111a and the screw portion 116a, and is formed so as to have substantially the same outer diameter as the opening 132a (see FIG. 11) formed in the tubular member 130a. There is. Further, the screw portion 116a is formed so as to have an outer diameter smaller than that of the intermediate portion 114a. Therefore, the screw portion 116a of the mounting portion 110a can be passed through the opening 132a of the tubular member 130a. In this state, the washer 117a and the nut 118a having an outer diameter larger than the opening 132a of the tubular member 130a are attached to the screw portion 116a. As a result, the mounting portion 110a can be fixed to the tubular member 130a (see FIG. 12). An accommodating portion 142a is formed in the inner housing 140a arranged inside the spring 120. This makes it possible to prevent the mounting portion 110a and the inner housing 140a from interfering with each other when the mounting portion 110a, the tubular member 130a, and the inner housing 140a are assembled as shown in FIG. It has become.

Further, the mounting portion 110a is formed with a counterbore hole 112a and a through hole 119a having a diameter smaller than that of the counterbore hole 112a, so that the rod-shaped member 152 of the maintenance portion 150 is installed inside the through hole 119a. It has become. Further, screw portions (not shown) for attaching the nut 154a are formed at both ends of the rod-shaped member 152, respectively. Further, as the nut 154a, a nut having an outer diameter larger than that of the through hole 119a is used. Therefore, after arranging the rod-shaped member 152 inside the counterbore hole 112a and the through hole 119a, by attaching the nut 154a to the screw portion of the rod-shaped member 152, the rod-shaped member 152 and the nut 154a are pulled out from the through hole 119a. Can be prevented.

Further, as shown in FIG. 9, as the rod-shaped member 152, the value obtained by adding the depths (lengths) of the through holes 119a and 119b of the mounting portions 110a and 110b and the lengths of the tubular members 130a and 130b. Those with a larger length have come to be used. Therefore, the nuts 154a and 154b can be attached to both ends of the rod-shaped member 152 in a state where the rod-shaped member 152 is arranged inside the through holes 119a and 119b and the tubular members 130a and 130b. Further, this makes it possible to maintain that one tubular member 130a and the other tubular member 130b do not move relatively. As shown in FIG. 11 and the like, since the inner housing 140a is provided with a through hole 144a, it is possible to prevent the rod-shaped member 152 of the maintenance portion 150 from interfering with the inner housing 140a. ing.

Further, as a retaining member for preventing the rod-shaped member 152 from coming off from each through hole 119a, a member other than each nut 154a may be used. For example, a retaining member that is placed around the rod-shaped member 152 and then fixed to the rod-shaped member 152 by being crimped may be used. Alternatively, the rod-shaped member 152 may be prevented from coming out of each through hole 119a by welding a retaining member having another configuration to the end portion of the rod-shaped member 152.

Further, inside the tubular members 130a and 130b as the first accommodating portion and the second accommodating portion arranged around the spring 120, the fixed portions 134a and 134b and the open portions 136a and 136b are respectively. It is formed. Further, each of the fixed portions 134a and 134b does not allow the extension of the spring 120 when the rod-shaped member 152 of the maintenance portion 150 breaks. Specifically, as shown in FIG. 9 and the like, the inner peripheral surfaces of the fixed portions 134a and 134b each have a shape along the contour of the spring 120, and the inner surfaces of the fixed portions 134a and 134b and the spring. It is arranged so that the outer surfaces of 120 are in contact with each other. On the other hand, each of the open portions 136a and 136b is configured so that the spring 120 does not come into contact with the spring 120 when the spring 120 is housed inside the tubular members 130a and 130b. Therefore, when the rod-shaped member 152 of the maintenance portion 150 is broken, the spring 120 is designed to allow the extension of the portion of the spring 120 facing each of the open portions 136a and 136b. Specifically, the open portions 136a and 136b of the tubular members 130a and 130b are composed of substantially cylindrical portions having an inner diameter larger than the outer diameter of the spring 120.

Further, fixed portions 146a and 146b and open portions 148a and 148b are formed on the outside of the inner housings 140a and 140b located inside the substantially cylindrical spring 120, respectively. Further, the fixed portions 146a and 146b do not allow the spring 120 to stretch when the rod-shaped member 152 of the maintaining portion 150 breaks. Specifically, as shown in FIG. 9 and the like, the outer peripheral surfaces of the fixed portions 146a and 146b each have a shape along the contour of the spring 120, and the outer peripheral surfaces of the fixed portions 146a and 146b and the spring 120. It is arranged so that the inner peripheral surfaces of the springs are in contact with each other. On the other hand, the open portions 148a and 148b are configured so as not to come into contact with the spring 120 when the inner housings 140a and 140b are housed inside the spring 120. For this reason, when the rod-shaped member 152 of the maintenance portion 150 breaks, the spring 120 allows the extension of the portion of the spring 120 facing each of the open portions 148a and 148b. Specifically, the open portions 148a and 148b of the inner housings 140a and 140b are composed of substantially cylindrical portions having an outer diameter smaller than the inner diameter of the spring 120.

As described above, in the shock absorbing unit 100, the rod-shaped member 152 breaks when an impact larger than a predetermined threshold value is applied to the shock absorbing unit 100. Due to the breakage of the rod-shaped member 152, a part of the shock applied to the shock absorbing unit 100 is absorbed. Further, when the rod-shaped member 152 is broken, the force for maintaining the tubular members 130a and 130b so as not to move relatively does not work, so that the spring 120 is allowed to stretch. Further, when the extension of the spring 120 is allowed, the extension of the spring 120 further absorbs the impact applied to the shock absorbing unit 100 (see FIG. 13). As described above, since the shock absorbing unit 100 absorbs the shock by breaking the rod-shaped member 152 and expanding and contracting the spring 22, the shock absorbing unit 100 can absorb the shock more effectively as compared with the configuration in which the shock is absorbed by friction. Further, since the shock absorbing unit 100 can be used again only by replacing the broken rod-shaped member 152 with a new rod-shaped member 152, the convenience for the user can be improved.

The rod-shaped member 152 of the maintenance portion 150 shown in FIG. 9 or the like is a rod-shaped member having a predetermined diameter and has no broken portion, but is not limited to such an embodiment. A broken portion may be formed in the rod-shaped member 152 by reducing the diameter of a part of the rod-shaped member 152 or by providing a recess or a notch. Further, the threshold value of the impact when the rod-shaped member 152 breaks may be adjusted by changing the diameter and the material of the rod-shaped member 152.

As described above, the configurations of the mounting portion 110a, each tubular member 130a and the inner housing 140a are substantially the same as the configurations of the mounting portion 110b, the tubular member 130b and the inner housing 140b. In other words, the mounting portion 110b has a mounting portion 111b, a counterbore hole 112b, an intermediate portion 114b, a screw portion 116b, a washer 117b, a nut 118b, and a through hole 119b. Further, the tubular member 130b further has an opening 132b. Further, the inner housing 140b further has an accommodating portion 142b and a through hole 144b.

Further, the installation of the inner housings 140a and 140b may be omitted. When the inner housings 140a and 140b are additionally installed, the spring 120 includes the fixing portions 134a and 134b of the tubular members 130a and 130b and the fixing portions 146a and 146b of the inner housings 140a and 140b. It will be sandwiched between. In this case, it is possible to more reliably prevent the portions of the spring 120 that are in contact with the fixed portions 134a, 134b, 146a, and 146b from being deformed.

Further, in the example shown in FIG. 9 and the like, the first tubular member and the second tubular member having substantially the same length are used, and the inner housings having substantially the same length are used. Although the mode to be used has been described, the present invention is not limited to such a configuration. For example, a first tubular member and a second tubular member having different lengths, or each inner housing may be used.

Further, as another example of the shock absorbing unit 10 of the present embodiment, those shown in FIGS. 14 to 17 may be used. 14 to 17 are explanatory views, top views, and cross-sectional views for explaining the configuration of still another example of the shock absorbing unit of the present invention, respectively. Here, FIGS. 15 and 16 are top views and cross-sectional views for explaining the configuration of still another example of the shock absorbing unit, respectively. 14 and 17, respectively, are explanatory views depicting the shock absorbing unit by combining a cross-sectional view and a top view for the purpose of making the configuration easy to understand.

The shock absorbing unit 200 shown in FIGS. 14 to 17 has a stretchable spring 220 and a fixing member 230 for fixing the spring 220 so as not to stretch. More specifically, the spring 220 has a substantially cylindrical shape, and the fixing member 230 is arranged inside the spring 220. Further, when an impact larger than a predetermined threshold value is applied to the shock absorbing unit 200, the fixing member 230 (specifically, the broken portion 238) breaks to absorb the shock applied to the shock absorbing unit 200. It is designed to do.

Specifically, the spring 220 is composed of a push spring, and the spring 220 can expand and contract along the longitudinal direction (that is, along the left-right direction in FIG. 14). In the example shown in FIG. 14 and the like, the spring 220 is fixed by the fixing member 230 in a state of being compressed along the longitudinal direction so that the coil portions are in close contact with each other. The spring 220 is made of a hard steel wire, a piano wire, a stainless steel wire, or the like.

Further, as shown in FIG. 15 and the like, attachment portions 232 such as female threads are formed at both ends of the fixing member 230, and attachment portions 210 are attached to these attachment portions 232, respectively. There is. Further, each mounting portion 210 allows the shock absorbing unit 200 to be mounted on the wire main body 330 of the rockfall prevention system 300, which will be described later. In the example shown in FIG. 14 and the like, each mounting portion 210 includes a substantially U-shaped mounting portion 212. Further, the mounting portion 212 is rotatable with respect to the fixing member 230 about an axis along the extending direction of the spring 220 (that is, the left-right direction in FIG. 14). Further, the mounting portion 212 is rotatable with respect to the fixing member 230 about an axis along a straight line connecting the ends of the substantially U-shaped mounting portion 212 (that is, an axis along the vertical direction in FIG. 14). It has become.

Further, the fixing member 230 is formed with a sealing member mounting portion 233, a fixing portion 234, an open portion 236, and a broken portion 238, respectively. As will be described later, sealing members 264 and 266 such as O-rings are attached to each sealing member mounting portion 233. Further, each fixed portion 234 is configured so as not to allow the spring 220 to stretch when the broken portion 238 is broken. Specifically, the outer peripheral surface of each fixed portion 234 has a shape along the contour of the inner peripheral surface of the spring 220, and the outer peripheral surface of each fixing member 230 and the inner peripheral surface of the spring 220 are mutually aligned. It is arranged so that it is in contact with each other. On the other hand, the open portion 236 is configured so that the fixing member 230 does not come into contact with the spring 220 when the fixing member 230 is housed inside the spring 220. Therefore, the extension of the spring 220 is allowed when the broken portion 238 of the fixing member 230 is broken. Specifically, the open portion 236 of the fixing member 230 is composed of a substantially cylindrical portion having an outer diameter smaller than the size of the inner diameter of the spring 220.

Further, in the shock absorbing unit 200, when a shock larger than a predetermined threshold value is applied to the shock absorbing unit 200, the broken portion 238 of the fixing member 230 is broken and the spring 220 is allowed to stretch. (See Fig. 17). Due to such breakage of the fixing member 230, a part of the impact applied to the impact absorbing unit 200 is absorbed. Further, when the fixing member 230 is broken, the force for maintaining the state as shown in FIG. 14 does not work, so that the extension of the spring 220 is allowed. Further, when the extension of the spring 220 is allowed, the extension of the spring 220 further absorbs the impact applied to the impact absorbing unit 200. As described above, since the shock absorbing unit 200 absorbs the shock by breaking the fixing member 230 and expanding and contracting the spring 220, the shock absorbing unit 200 can absorb the shock more effectively as compared with the configuration in which the shock is absorbed by friction.

The broken portion 238 is the portion having the smallest diameter in the fixing member 230, and in the example shown in FIG. 15 and the like, the fractured portion 238 is formed at a substantially central portion in the extending direction of the fixing member 230. Further, the breaking load (tensile stress) of the broken portion 238 can be calculated by a known method based on the material of the fixing member 230, the size of the diameter of the broken portion 238, and the like. Further, by changing the material of the fixing member 230 and the size of the diameter of the broken portion 238, the threshold value of the magnitude of the impact when the broken portion 238 is broken can be adjusted. Further, the fractured portion 238 may be formed at a position other than substantially the center in the extending direction of the fixing member 230.

As shown in FIGS. 14 and 16, the shock absorbing unit 200 is arranged at a position where the protective member is arranged around the spring 220 and is in contact with the protective member, and seals the spring 220 in a liquid-tight manner. It includes members 262, 264, and 266. Specifically, the protective member is composed of a combination of the first tubular member 240 and the second tubular member 250. Further, the spring 220 is arranged inside the first tubular member 240 and the second tubular member 250. More specifically, a part of the spring 220 is housed inside the first tubular member 240, and the rest of the spring 220 is housed inside the second tubular member 250. There is.

Further, an opening 242 is formed in the first tubular member 240, and one end portion (specifically, one attached portion 232) of the fixing member 230 is formed through the opening 242. It is exposed to the outside of the tubular member 240. Further, an opening 252 is formed in the second tubular member 250, and the other end portion (specifically, the other attached portion 232) of the fixing member 230 is formed through the opening 252. It is exposed to the outside of the tubular member 250. Then, the attachment portion 210 is attached to each attachment portion 232 of the fixing member 230 exposed to the outside.

Further, in the vicinity of the end of the first tubular member 240 on the side opposite to the opening 242, a sealing member is attached, which is composed of recesses formed over the entire circumference of the first tubular member 240 along the circumferential direction. Part 248 is formed. Further, in the vicinity of the end portion of the second tubular member 250 opposite to the opening 252, an extension portion 258 having an outer diameter larger than the outer diameter of the end portion of the first tubular member 240 is provided. There is. Further, the extension portion 258 of the second tubular member 250 is a first cylinder when the first tubular member 240 and the second tubular member 250 are combined so as to be in the state shown in FIG. The length is formed so as to cover the region of the shape member 240 including the sealing member mounting portion 248. Therefore, by attaching a sealing member 262 such as an O-ring to the sealing member mounting portion 248 of the first tubular member 240, the first tubular member 240 and the second tubular member 250 come into contact with each other. It is possible to prevent the spring 220 from getting wet due to liquid such as water entering from the portion (see FIG. 14).

Further, sealing members 262 and 264 such as O-rings are installed in each sealing member mounting portion 233 formed of recesses formed over the entire circumference of the fixing member 230 in the circumferential direction. As shown in FIG. 14, a sealing member 264 is mounted between the sealing member mounting portion 233 provided at one end of the fixing member 230 and the first tubular member 240. ing. Further, a sealing member 266 is mounted between the other sealing member mounting portion 233 formed on the fixing member 230 and the second tubular member 250. Due to these sealing members 262 and 264, the spring 220 also gets wet when a liquid such as water enters through the opening 242 of the first tubular member 240 or the opening 252 of the second tubular member 250. Can be prevented.

Further, fixed portions 244 and 254 and open portions 246 and 256 are formed inside the first tubular member 240 and inside the second tubular member 250, respectively. Specifically, each of the fixing portions 244 and 254 is configured so as not to allow the extension of the spring 220 when the broken portion 238 of the fixing member 230 is broken. As shown in FIG. 14 and the like, the inner peripheral surface of each of the fixed portions 244 and 254 has a shape along the contour of the spring 220, and the inner peripheral surface of each of the fixed portions 244 and 254 and the outer peripheral surface of the spring 220. They are arranged so that the surfaces are in contact with each other. On the other hand, each of the open portions 246 and 256 is configured so as not to come into contact with the spring 220 when the spring 220 is housed inside the first tubular member 240 and the second tubular member 250. Therefore, the extension of the spring 220 is allowed when the broken portion 238 of the fixing member 230 is broken. Specifically, each of the open portions 246 and 256 of the first tubular member 240 and the second tubular member 250 is composed of a substantially cylindrical portion having an inner diameter larger than the outer diameter of the spring 220. ing.

Note that grease injection ports for injecting grease may be formed in the first tubular member 240 and the second tubular member 250 of the shock absorbing unit 200 described above, respectively. Also in this case, by attaching a cap having a corresponding shape to each grease injection port, it is possible to prevent liquid such as water from infiltrating from the grease injection port.

Here, the shock absorbing unit 50 of the prior art is shown in FIG. In the shock absorbing unit 50 of the prior art, a part of the wire main body 52 is wound in an annular shape so as to overlap in the radial direction, and the overlapped portion is crimped by the tightening member 54 to fix the annular portion. It has become so. Further, a part of the impact applied to the shock absorbing unit 50 is absorbed by the frictional force acting between the wire main bodies 52 and the frictional force acting between the wire main body 52 and the tightening member 54. .. That is, when the impact is absorbed, the size of the ring of the annular portion of the wire body 52 becomes smaller. On the other hand, the shock absorbing units 10, 20, 100, and 200 according to the present embodiment break the fixing members 14, 24, 152, and 230 as described above. Then, the springs 12, 22, 120, and 220 are expanded and contracted to absorb the impact. Therefore, it is possible to obtain a higher impact absorption effect than the conventional technique of absorbing impact by friction. Further, even if an impact smaller than the above-mentioned predetermined threshold value is applied to the shock absorbing units 10, 20, 100, 200, the fixing members 14, 24, 152, and 230 are prevented from breaking. For this reason, it is possible to lengthen the interval for maintenance and replacement of the shock absorbing units 10, 20, 100, and 200 as compared with the conventional technology in which the wire is easily stretched even with a small impact, and the shock absorbing units 10, 20, 100 can be extended. , 200 conveniences can be improved. In addition, it is possible to prevent the broken fixing members 14, 24, 152, and 230 from being scattered.

When the push spring described above is used as the springs 12, 22, 120, 220, the springs 12, 22, 120, 220 are limited to a configuration in which the springs 12, 22, 120, and 220 are fixed by the fixing members 14, 24, 152, and 230 in a compressed state. Will not be done. The springs 12, 22, 120, 220 in a state where the coil portions are not compressed so that there is a gap between the coil portions may be fixed by the fixing members 14, 24, 152, 230. Alternatively, as the springs 12, 22, 120, and 220, a substantially cylindrical pull spring (tension coil spring) may be used instead of the push spring described above. Here, the pull spring (tension coil spring) is generally wound with the coil portions in close contact with each other so as not to form a gap between the coils forming the spring portion.

Next, as an example of the rockfall prevention system using the shock absorbing units 10, 20, 100, 200 of the present implementation, the rockfall prevention system 300 provided with the shock absorbing unit 10 as shown in FIGS. 19 and 20 will be described. .. Further, in FIG. 20, a falling object falling along a slope 400 such as a mountain is indicated by reference numeral D. Although the rockfall prevention system 300 including the shock absorbing unit 10 will be described below, the rockfall prevention system may be configured by using the shock absorbing units 20, 100, and 200 instead of the shock absorbing unit 10.

When the rockfall prevention system 300 shown in FIGS. 19 and 20 is installed on a slope 400 such as a mountain, a falling object such as a stone that falls from the mountain side to the valley side along the slope 400 (see, for example, FIG. 20). It is used to receive (indicated by reference numeral D). Further, the rockfall prevention system 300 includes a support column 310, a falling object receiving member 320 stretched on each support column 310, a wire body 330 stretched between the support column 310 and the slope 400 on the mountain side, and a wire body 330. It has a shock absorbing unit 10 connected to. Specifically, the columns 310 are arranged on the slope 400 at predetermined intervals, and the falling object receiving member 320 stretched on each column 310 receives the falling object falling along the slope 400. It has become. Then, the impact when the falling object is received by the falling object receiving member 320 is absorbed by the shock absorbing unit 10 or the like.

Further, the wire main body 330 is composed of a plurality of wire portions, and an annular member is provided at the end of each wire portion as a connecting member for connecting the wire portion and the shock absorbing unit 10. Then, the tip of each hook 13 of the shock absorbing unit 10 is inserted into the annular member of each wire portion, so that the wire main body 330 and the shock absorbing unit 10 are connected to each other. Each wire portion of the wire body 330 and each hook 13 of the shock absorbing unit 10 may be connected by welding or the like. Further, a connecting member different from the annular member may be provided at the end of each wire portion of the wire main body 330. When the rockfall prevention system 300 is configured by using the shock absorbing units 20, 100, and 200, an appropriate connecting member is separately provided for each wire portion of the wire main body 330.

Further, in the rockfall prevention system 300 shown in FIG. 19 and the like, a plurality of (specifically, two) shock absorbing units 10 are connected in series to one wire main body 330 composed of a plurality of wire portions. In the present embodiment, the ones having different threshold values of the magnitude of the impact at which the fixing member 14 breaks when an impact is applied to the impact absorbing unit 10 are used. According to such a configuration, the rockfall prevention system 300 can appropriately absorb impacts of various sizes. As an example, each impact absorbing unit 10 provided with the fixing member 14 having the above-mentioned impact magnitude threshold value of the first value, and a second value having the impact magnitude threshold value larger than the first value. Consider a case in which a shock absorbing unit 10 provided with a certain fixing member 14 is provided. In this case, when an impact larger than the first value but smaller than the second value is applied to each impact absorption unit 10, the impact absorption threshold value is the first value. Only the fixing member 14 of the unit 10 breaks. On the other hand, when an impact larger than the sum of the first value and the second value is applied to each impact absorbing unit 10, the fixing members 14 of both impact absorbing units 10 are broken. Further, when an impact larger than the first value and smaller than the sum of the first value and the second value is applied to the shock absorbing unit 10, the fixing member of either one of the shock absorbing units 10 is applied. 14 will break.

The number of shock absorbing units 10 connected to one wire main body 330 composed of a plurality of wire portions is not limited to two. Only one shock absorbing unit 10 may be connected to one wire main body 330, or three or more shock absorbing units 10 may be connected to one wire main body 330. Further, a plurality of units having substantially the same threshold value of the magnitude of the impact at which the fixing member 14 breaks when an impact is applied to the impact absorbing unit 10 may be directly arranged.

Further, each support column 310 is installed at a position substantially equal in height level when viewed from the slope 400 via each base member 312 fixed to the slope 400. Further, as shown in FIG. 20, each support column 310 and each base member 312 are connected by, for example, a hinge 314 that opens on both sides. Therefore, each support column 310 can be swung with respect to each base member 312 (that is, the slope 400) (see arrow A in FIG. 20). As a result, the stress acting on each column 310 when the falling object is received by the falling object receiving member 320 can be reduced. The member connecting each support column 310 and each base member 312 is not limited to the hinge 314 described above, and other members may be used.

Further, in the rockfall prevention system 300 shown in FIGS. 19 and 20, a wire mesh is used as a falling object receiving member 320 for receiving a falling object. As the falling object receiving member, for example, a fence made of a metal rod, a plate, or the like, or a ring-shaped net may be used.

Here, as a conventional rock fall prevention system, by allowing the wire connected to the falling object receiving member to stretch as shown in FIG. 18, when the falling object is received by the falling object receiving member, the wire is added to the wire. It is known to use a shock absorbing unit that absorbs the shock. However, in the above configuration, the wire is stretched even when the magnitude of the impact applied is small, and the wire is easily stretched even with a small impact, so there is a problem that it is necessary to perform maintenance of the wire at relatively short intervals. there were. On the other hand, according to the rockfall prevention system 300 according to the present embodiment, the shock absorbing unit 10 that absorbs the shock only when a shock larger than a predetermined threshold value is applied is used. This makes it possible to reduce the time and effort required for maintenance of the rockfall prevention system 300.

Further, since the wire main body 330 and the shock absorbing unit 10 of the rockfall prevention system 300 are installed in a substantially linearly extended state, adverse effects on the wire main body 330 are suppressed after the fixing member 14 of the shock absorbing unit 10 is broken. You can do it. That is, in the shock absorbing unit 50 of the prior art as shown in FIG. 18, the wire main body 52 is crimped by the tightening member 54 in a state of being wound once in an annular shape. Therefore, even after the shock absorbing unit 50 absorbs the shock (that is, after the annular portion is reduced), the wire main body 52 is in a state of being wound once in an annular shape. If a further impact is applied to the shock absorbing unit 50 in this state, a large load is applied to the portion where the wire body 52 and the tightening member 54 are in contact with each other, and the wire body 52 may break from the location. There is sex. On the other hand, in the present embodiment, since the wire body 330 and the shock absorbing unit 10 are installed in a state of extending substantially linearly, it is possible to prevent the above-mentioned problems from occurring. be able to. Further, it is possible to prevent the wire body 330 from being twisted after the fixing member 14 of the shock absorbing unit 10 is broken.

The shock absorbing units 10, 20, 100, and 200 for absorbing shocks having the above configuration fix the expandable springs 12, 22, 120, 220 and the springs 12, 22, 120, 220. It has fixing members 14, 24, 130, 230 for the purpose. Then, the fixing members 14, 24, 130, and 230 are broken when the magnitude of the impact applied to the impact absorbing units 10, 20, 100, and 200 is larger than a predetermined threshold value. As described above, the fixing members 14, 24, 130 and 230 are broken and the springs 12, 22, 120 and 220 are expanded and contracted only when an impact larger than a predetermined threshold value is applied. Therefore, it is possible to absorb the impact when the fixing members 14, 24, 130, and 230 break. Further, since the fixing members 14, 24, 130, and 230 are broken to absorb the impact, the impact can be absorbed more effectively as compared with the configuration in which the impact is absorbed by friction. Further, in the shock absorbing units 10, 20, 100, 200, the springs 12, 22, 120, 220 are push springs or pull springs. When a push spring is used as the springs 12, 22, 120, 220, the fixing members 14, 24, 130, 230 have the springs 12, 22, 120, 220 compressed along the longitudinal direction. It is designed to be fixed.

Further, in the shock absorbing units 10, 20, 100, and 200 described above, the fixing members 14, 24, 152, and 230 are provided with broken portions 18, 238. Then, when the magnitude of the impact applied to the impact absorbing units 10, 20, 100, 200 is larger than a predetermined threshold value, the fixing members 14, 24, 152, 230 are fractured along the fractured portions 18, 238. It has become like. In this way, when the fractured portions 18, 238 are provided, it is possible to specify from which location the fixing members 14, 24, 152, and 230 are fractured, so that the shock absorbing units 10, 20, 100, and 200 can be specified. Convenience can be improved.

Further, in the shock absorbing unit 10 described above, the fixing member 14 is arranged around the spring 12, and the fixing portion 15 and the open portion 16 are formed inside the fixing members 14 and 24. .. Further, the fixing portion 15 does not allow the extension of the spring 12 when the fixing member 14 is broken. Further, the open portion 16 allows the spring 12 to stretch when the fixing member 14 breaks.

Further, in the shock absorbing units 20 and 100 described above, the fixing members 24 and 130 have first accommodating portions 24a and 130a, second accommodating portions 24b and 130b, and a maintenance portion 150. Further, the first accommodating portions 24a and 130a accommodate a part of the springs 22 and 120 inside, and the second accommodating portions 24b and 130b accommodate a part of the springs 22 and 120 inside. It is designed to be accommodated. Further, the maintenance portions 28a and 150 are designed to maintain the first accommodating portions 24a and 130a so that the second accommodating portions 24b and 130b do not move relatively. Then, when the magnitude of the impact applied to the impact absorbing units 20 and 100 is larger than a predetermined threshold value, the maintenance portions 28a and 150 are broken. Further, inside the first accommodating portions 24a, 130a and the second accommodating portions 24b, 130b of the fixing members 24, 130, the fixing portions 25a, 25b, 134a, 134b and the open portions 26a, 26b, 136a, 136b And are formed respectively. Further, the fixed portions 25a, 25b, 134a and 134b do not allow the springs 22 and 120 to stretch when the maintenance portions 28a and 150 are broken. Further, the open portions 26a, 26b, 136a and 136b allow the springs 22 and 120 to stretch when the maintenance portions 28a and 150 are broken.

Further, in the shock absorbing unit 100 described above, the maintenance portion 150 of the fixing member 130 includes a rod-shaped member 152 arranged inside the spring 120. Then, when the magnitude of the impact applied to the impact absorbing unit 100 is larger than a predetermined threshold value, the rod-shaped member 152 breaks, so that the impact is absorbed. Therefore, even if the rod-shaped member 152 breaks, the shock absorbing unit 100 can be used again simply by replacing the rod-shaped member 152 with a new rod-shaped member 152.

Further, in the shock absorbing unit 200 described above, the fixing member 230 is arranged inside the spring 220. Further, on the outside of the fixing member 230, there are a fixed portion 234 that does not allow the spring 220 to stretch when the fixing member 230 breaks, and an open portion 236 that allows the spring 220 to stretch when the fixing member 230 breaks. It is formed. Further, the shock absorbing unit 200 includes a protective member (specifically, a first tubular member 240 and a second tubular member 250) arranged around the spring 220 and a sealing member 262, 264, 266. And further equipped. Further, each sealing member 262, 264, 266 is arranged at a position where it comes into contact with the protective member, and the spring 220 is liquid-tightly sealed. This makes it possible to prevent the spring 220 from getting wet or rusting, so that the shock absorbing unit 200 can be suitably used in water, for example.

Further, the rockfall prevention system 300 having the above configuration includes a plurality of columns 310 arranged on the slope 400 at predetermined intervals, a falling object receiving member 320, a wire main body 330, and the above-mentioned impact absorption. It includes units 10, 20, 100, and 200. More specifically, the falling object receiving member 320 is stretched on each support column 310 to receive the falling object falling along the slope 400. Further, the wire main body 330 is stretched between each support column 310 and the slope 400 on the mountain side, and the shock absorbing units 10, 20, 100, and 200 are connected to the wire main body 330. Then, when the magnitude of the impact when the falling object is received by the falling object receiving member 320 is larger than a predetermined threshold value, the fixing members 14, 24, 152, 230 of the impact absorbing units 10, 20, 100, 200 Breaks. Therefore, the impact can be absorbed more effectively as compared with the conventional configuration in which the impact is absorbed by friction. Further, the installation of the valley side wire (that is, the shock absorbing units 10 and 20 arranged on the valley side and the wire main body 330) can be omitted, and the time and effort for maintenance of the rockfall prevention system 300 can be reduced. Further, as the shock absorbing units 10, 20, 100, 200, the magnitude of the impact that the fixing members 14, 24, 152, 230 break when the impact absorbing units 10, 20, 100, 200 are subjected to an impact. A plurality of types having different thresholds are used so as to be arranged in series. As a result, the rockfall prevention system 300 can appropriately absorb impacts of various sizes.

The shock absorbing units 10, 20, 100, 200 and the rockfall prevention system 300 according to the present embodiment are not limited to the above-described aspects, and various changes can be made.

For example, an example in which a push spring or a pull spring having a substantially cylindrical shape is used as the springs 12, 22, 120, and 220 has been described, but the present invention is not limited to such a configuration. A push spring or pull spring having a substantially conical shape or a push spring or pull spring having a substantially barrel shape may be used. Also in this case, the shock absorbing unit of the present invention can be configured by using the fixing member having the corresponding shape.

Further, although an example in which the springs 12, 22, 120 and 220 are formed from a hard steel wire, a piano wire and a stainless steel wire has been described, the springs 12, 22, 120 and 220 may be formed from other materials. good. Further, the surfaces of the springs 12, 22, 120 and 220 may be plated.

Further, as the fixing members for fixing the springs 12, 22, 120, the fixing members 14, 24, 130, 230 shown in FIGS. 1, 6, 130, 230 have been described, but fixing members having other configurations are used. You may do so. As the fixing member, a member having an opening on the outer peripheral surface of a substantially cylindrical sleeve may be used, or a slit (notch) extending from the upper end to the lower end of the substantially cylindrical sleeve is formed. May be used. In this way, when the fixing member is provided with an opening or a slit, the states of the springs 12, 22, and 120 can be confirmed from the outside, so that the maintenance of the shock absorbing units 10, 20, and 100 can be easily performed. Will be able to.

Further, fixing members 14, 24, 130, 230 having a configuration different from the examples shown in FIGS. 4, 6, 9, 14, 14 and the like may be used. For example, the regions of the fixed portions 15, 25a, 25b, 134a, 134b, and 234 may be reduced from the states shown in FIGS. 4, 6, 9, 14, and 14. On the other hand, the regions of the open portions 16, 26a, 26b, 136a, 136b, and 236 may be enlarged. In this way, when the area of the open portion is increased, the amount of extension of the springs 12, 22, 120, and 220 increases when the fixing member breaks, so that the springs 12, 22, 120, and 220 absorb the springs 12, 22, 120, and 220. It is possible to increase the amount of impact energy that can be produced.

Further, as an example in which the spring 12 and the hook 13 are made of separate members as mounting members provided at both ends of the spring 12 of the shock absorbing unit 10, a mounting member having another shape is attached to the spring 12. It may be provided. For example, a spring and a mounting member are integrally molded by molding the end of a metal wire constituting the spring 12 into a substantially S-shape, a substantially U-shape, or a substantially V-shape. You may. Further, as the mounting members provided at both ends of the spring 22 of the shock absorbing unit 20, the above-mentioned substantially S-shaped, substantially U-shaped or substantially V-shaped hooks may be used.

Further, an example in which the fractured portion 18 is provided at the substantially central portion of the open portion 16 of the fixing member 14 of the shock absorbing unit 10 has been described, but the present invention is not limited to such a configuration, and for example, near the end portion of the open portion 16. May be provided with a broken portion 18. In other words, if the broken portion 18 is provided at any portion of the open portion 16 of the fixing member 14, the shock absorbing unit 10 can exert the above-mentioned effect.

Further, an example in which the substantially cylindrical knock pins 28a and 28b are inserted into the substantially circular openings 27a and 27b27c as the fixing member 24 of the shock absorbing unit 20 has been described, but the present invention is not limited to such an example. .. A knock pin having a substantially triangular prism shape may be inserted into the opening having a substantially triangular shape, or another polygonal opening may be provided and a knock pin having a corresponding shape may be inserted into the opening.

Further, a broken portion may be formed on each of the knock pins 28a and 28b of the shock absorbing unit 20. For example, a groove having a substantially V-shaped cross section, such as the fractured portion 18 of the shock absorbing unit 10 shown in FIG. 1 or the like, may be formed on the outer peripheral surfaces of the knock pins 28a and 28b having a substantially cylindrical shape.

Also, it is not always necessary to attach the shock absorbing units 10, 20, 100, 200 to all the columns 310. When the strength of the rockfall prevention system is guaranteed, the strut 310 to which the wire body 330 to which the shock absorbing units 10, 20, 100, and 200 are connected is connected to the shock absorbing units 10, 20, 100, and 200. The support columns 310 to which the unwired wire main body 330 is attached may be arranged alternately. Alternatively, a strut 310 to which the wire body 330 to which the shock absorbing units 10, 20, 100, and 200 are connected is attached, and a strut to which the wire body 330 to which the shock absorbing units 10, 20, 100, and 200 are not connected are attached. The 310 may be arranged differently from the one described above.

The applications of the shock absorbing units 10, 20, 100, and 200 described above are not limited to the rockfall prevention system 300 described above. For example, the shock absorbing units 10, 20, 100, 200 described above can be used in various civil engineering structures and constructions. Specifically, the shock absorbing units 10 and 20 described above are used for seismic retrofitting of bridge superstructures to prevent the bridge from falling during a large-scale earthquake, and seismic retrofitting of bridge substructures to reinforce bridge piers by winding them with reinforced concrete. , 100, 200 may be used. In this case, the seismic resistance of the upper part of the bridge and the lower part of the bridge can be improved. Further, the shock absorbing units 10, 20, 100, and 200 described above may be used as the energy absorbing device in the bridge collapse prevention system. More specifically, it is used to limit the movement of girders with respect to the substructure of the bridge, such as abutments, and to absorb the impact applied to the bridge when a large seismic force is applied to the bridge due to an earthquake or the like. As the member, the shock absorbing units 10, 20, 100, and 200 described above may be used. More specifically, the shock absorbing units 10, 20, 100, and 200 may be used to prevent a large displacement of the girder in the direction of the bridge axis and a large displacement of the girder in the direction perpendicular to the bridge axis. Further, in a bridge having a structure including a plurality of girders, a certain girder and a girder located next to the girder may be connected via the shock absorbing units 10, 20, 100, 200. Further, by using the shock absorbing units 10, 20, 100, and 200 as the guardrail and the median strip, the shock when a vehicle or the like collides may be absorbed. Further, the shock absorbing units 10, 20, 100 and 200 can be used for various other purposes.

Claims (12)

1. A shock absorbing unit for absorbing shock
   It has a stretchable spring and a fixing member for fixing the spring.
   A shock absorbing unit in which the fixing member breaks when the magnitude of the shock applied to the shock absorbing unit is larger than a predetermined threshold value.
2. The spring is a push spring and
   The shock absorbing unit according to claim 1, wherein the fixing member fixes the spring in a compressed state along the longitudinal direction.
3. The shock absorbing unit according to claim 1, wherein the spring is a pulling spring.
4. The fixing member is provided with a broken portion, and the fixing member is provided with a broken portion.
   The shock absorbing unit according to any one of claims 1 to 3, wherein the fixing member breaks along the broken portion when the magnitude of the shock applied to the shock absorbing unit is larger than a predetermined threshold value. ..
5. The fixing member is arranged around the spring and
   Inside the fixing member, a fixing portion that does not allow the spring to stretch when the fixing member breaks and an open portion that allows the spring to stretch when the fixing member breaks are formed. , The shock absorbing unit according to any one of claims 1 to 4.
6. The fixing member includes a first accommodating portion for accommodating a part of the spring inside, a second accommodating portion for accommodating a part of the spring inside, the first accommodating portion, and the first accommodating member. It has a maintenance part for maintaining the accommodation part of 2 so that it does not move relatively.
   The shock absorbing unit according to any one of claims 1 to 4, wherein the maintenance portion breaks when the magnitude of the shock applied to the shock absorbing unit is larger than a predetermined threshold value.
7. Inside the first accommodating portion and the second accommodating portion of the fixing member, a fixing portion that does not allow the extension of the spring when the maintenance portion is broken and the fixing portion that does not allow the extension of the spring when the maintenance portion is broken are described. The shock absorbing unit according to claim 6, wherein each of the open portions that allow the extension of the spring is formed.
8. The maintenance portion of the fixing member includes a rod-shaped member arranged inside the spring.
   The shock absorbing unit according to claim 6 or 7, wherein the rod-shaped member breaks when the magnitude of the shock applied to the shock absorbing unit is larger than a predetermined threshold value.
9. The fixing member is arranged inside the spring, and the fixing member is arranged inside the spring.
   On the outside of the fixing member, a fixing portion that does not allow the spring to stretch when the fixing member breaks and an open portion that allows the spring to stretch when the fixing member breaks are formed. , The shock absorbing unit according to any one of claims 1 to 4.
10. A protective member arranged around the spring and
    The shock absorbing unit according to claim 9, further comprising a sealing member arranged at a position in contact with the protective member and liquid-tightly sealing the spring.
11. With multiple stanchions arranged on the slope at regular intervals,
    A falling object receiving member that is stretched on each of the columns and receives a falling object that falls along the slope.
    A wire body stretched between each of the columns and the slope on the mountain side,
    A shock absorbing unit connected to the wire body, which has a stretchable spring and a fixing member for fixing the spring, and the magnitude of the shock applied to the shock absorbing unit is predetermined. A shock absorbing unit in which the fixing member breaks when it is larger than the threshold value of
    A rockfall prevention system equipped with.
12. 11. The impact unit according to claim 11, wherein a plurality of types having different threshold values of the magnitude of the impact at which the fixing member breaks when an impact is applied to the impact absorbing unit are arranged in series. Rockfall prevention system.

Images