JP7356145B2 - Shock absorption unit and rockfall prevention system - Google Patents

Description

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

BACKGROUND ART Conventionally, in rockfall protection fences installed on mountain slopes or the like to catch falling rocks, shock absorption units have been used to absorb the impact when the rockfall protection fence catches falling rocks. More specifically, as a rockfall protection fence using such a shock absorption unit, the one disclosed in FIG. 1 of Patent Document 1 and the like is known.

The fall protection fence disclosed in FIG. 1 of Patent Document 1 consists of columns arranged on a slope at predetermined intervals, a mountain side wire stretched between the upper end of the column and the slope on the mountain side, and a mountain side wire stretched between the upper end of the column and the slope on the mountain side. It has a ring-type net stretched between them to catch falling rocks. In addition, by allowing the mountain wire, etc. to deform (stretch) when a falling rock is caught by the ring type net, a portion of the impact applied to the mountain wire, etc. is absorbed by the elongation of the mountain wire, etc. It has become. More specifically, a part of the mountain wire is wound once so as to overlap in the radial direction of the mountain wire to form an annular part, and a tightening member placed in this overlapped part is caulked to form the annular part. The parts are fixed. When an impact is applied, the size of the ring in the annular portion becomes smaller, so that part of the impact when catching a falling rock is absorbed by the frictional force acting between the mountain side wire and the tightening member. It has become so.

Patent No. 5978022

However, the conventional shock absorption unit as disclosed in Patent Document 1 absorbs the shock applied to the wire by allowing the wire to elongate, and with the above configuration, the magnitude of the applied shock is small. Sometimes the wires are stretched. As described above, since the wire tends to stretch even with a small impact, there is a problem in that it is necessary to perform maintenance on the impact absorption unit at relatively short intervals.

The present invention has been made in consideration of these points, and provides a shock absorbing unit that can absorb shock by having a fixed member break only when a shock larger than a predetermined threshold is applied. Another object of the present invention is to provide a rockfall prevention system using such a shock absorbing unit.

The shock absorption unit of the present invention is a shock absorption unit for absorbing shock, and includes an extensible spring and a fixing member for fixing the spring. The fixing member 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 fixed member breaks and the spring expands and contracts only when a shock larger than a predetermined threshold is applied, so that the shock is not applied when the fixed member breaks. It can be made to absorb.

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

Alternatively, the spring may be a tension spring.

In the shock absorbing unit of the present invention, the fixing member is provided with a breaking portion, and when the magnitude of the impact applied to the shock absorbing unit is larger than a predetermined threshold value, the fixing member is disposed at the breaking portion. It may be broken along.

Further, in the shock absorption unit of the present invention, the fixing member is arranged around the spring, and a fixing member is provided inside the fixing member that does not allow the spring to elongate when the fixing member is broken. and an open portion that allows the spring to stretch when the fixing member is broken.

Further, the fixing member includes a first housing part for housing a part of the spring therein, a second housing part for housing a part of the spring therein, and the first housing part. and a maintenance part for maintaining the second storage part from moving relative to the second storage part, and the maintenance part is configured to maintain the impact absorption unit when the magnitude of the impact applied to the shock absorption unit is larger than a predetermined threshold. A portion may be broken.

In this case, inside the first accommodating part and the second accommodating part of the fixing member, there is a fixing part that does not allow the spring to stretch when the maintaining part breaks, and a fixing part that does not allow the spring to stretch when the maintaining part breaks. In some cases, an open portion may be formed to allow the spring to stretch.

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

Further, in the shock absorbing unit of the present invention, the fixing member is arranged inside the spring, and a fixing member is provided outside the fixing member 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 is broken.

The shock absorption unit of the present invention may further include a protection member disposed around the spring, and a sealing member disposed at a position in contact with the protection member to liquid-tightly seal the spring. good.

The rockfall prevention system of the present invention includes: a plurality of pillars arranged on a slope at predetermined intervals; a falling object receiving member stretched across each of the pillars to catch falling objects falling along the slope; A wire body stretched between the pillar and the slope on the mountain side, and a shock absorption unit connected to the wire body, the shock absorbing unit having an expandable spring and a fixing member for fixing the spring. and 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 this type of rock fall prevention system, the fixed part breaks only when an impact larger than a predetermined threshold is applied, and the shock absorption unit absorbs the impact by expanding and contracting the spring, thereby reducing maintenance. It can save you time and effort.

In the rockfall prevention system of the present invention, a plurality of types of impact units are arranged in series, each having a different threshold of the magnitude of impact at which the fixed member breaks when an impact is applied to the impact absorption unit. may be used as such.

According to the shock absorption unit and rockfall prevention system of the present invention, the fixed member breaks only when an impact larger than a predetermined threshold is applied, thereby absorbing the impact applied to the impact absorption unit. be able to.

FIG. 1 is a perspective view showing the configuration of a shock absorption unit according to an embodiment of the present invention. FIG. 2 is a top view showing the configuration of a compressed spring provided in the shock absorption unit shown in FIG. 1; FIG. 2 is a sectional view showing the configuration of a fixing member provided in the shock absorption unit shown in FIG. 1. FIG. FIG. 2 is an explanatory diagram for explaining the configuration of a fixing member of the shock absorption unit shown in FIG. 1. FIG. FIG. 2 is an explanatory diagram for explaining the configuration when the fixing member of the shock absorbing unit shown in FIG. 1 etc. is broken. FIG. 3 is an explanatory diagram showing the configuration of another example of the shock absorption unit according to the present embodiment. 7 is an explanatory diagram for explaining the configuration of a fixing member of the shock absorption unit shown in FIG. 6. FIG. FIG. 7 is an explanatory diagram for explaining the configuration when the fixing member of the shock absorption unit shown in FIG. 6 is broken. FIG. 7 is an explanatory diagram showing the configuration of still another example of the shock absorption unit according to the present embodiment. FIG. 10 is a top view showing the configuration of a mounting portion of the shock absorption unit shown in FIG. 9; FIG. 9 is a cross-sectional view showing the structure of a fixing member and an inner housing of the shock absorbing unit shown in FIG. 9 and the like. FIG. 9 is an explanatory diagram showing a configuration when the mounting portion, fixing member, and inner housing of the shock absorption unit shown in FIG. 9 etc. are assembled. FIG. 9 is an explanatory diagram for explaining the configuration when the fixing member of the shock absorbing unit shown in FIG. 9 etc. is broken. FIG. 7 is an explanatory diagram showing the configuration of still another example of the shock absorption unit according to the present embodiment. FIG. 15 is a top view showing the configuration of a fixing member of the shock absorption unit shown in FIG. 14 and the like. FIG. 15 is a cross-sectional view showing the structure of a protection member of the shock absorption unit shown in FIG. 14; 15 is an explanatory diagram for explaining the configuration when the fixing member of the shock absorption unit shown in FIG. 14 etc. is broken. FIG. FIG. 2 is a perspective view showing the structure of a shock absorbing unit according to the prior art. FIG. 2 is a perspective view schematically showing the configuration of a rockfall prevention system using the shock absorption unit shown in FIG. 1 and the like. 20 is a side view schematically showing the configuration of the rockfall prevention system shown in FIG. 19. FIG.

Embodiments of the present invention will be described below with reference to the drawings. 1 to 20 are diagrams for explaining a shock absorption unit and a rock fall prevention system according to this embodiment. Of these, FIG. 1 is a block diagram showing the structure of the shock absorption unit according to the present embodiment, and FIGS. 2 and 3 are a top view and a fixed view showing the structure of the spring of the shock absorption unit shown in FIG. 1, respectively. FIG. 3 is a cross-sectional view showing the structure of the member. Moreover, FIGS. 4 and 5 are explanatory diagrams for explaining the structure before and after the fixing member of the shock absorbing unit shown in FIG. 1 is broken, respectively. Further, FIGS. 6 to 8 are explanatory diagrams for explaining the configuration of other examples of the shock absorption unit according to the present embodiment. Further, FIGS. 9 to 13 are a top view, a sectional view, and an explanatory view, respectively, for explaining the configuration of still another example of the shock absorption unit according to the present embodiment. 14 to 17 are a top view, a sectional view, and an explanatory view, respectively, for explaining the configuration of still another example of the shock absorption unit according to the present embodiment. Moreover, FIG. 18 is a perspective view showing the structure of a shock absorption unit according to the prior art. Further, FIG. 19 is a perspective view schematically showing the configuration of a rockfall prevention system using the shock absorption unit shown in FIG. 1 etc., and FIG. 20 schematically shows the configuration of the rockfall prevention system shown in FIG. 19. FIG. In order to make it easier to understand the configuration when the fixing member breaks and the spring stretches, in FIGS. 4 to 8, cross-sectional views are shown for the fixing member, while top views are shown for the spring and the mounting member. ing. Further, although details will be described later, still other examples of the shock absorption unit are depicted in FIGS. 9 and 14 by combining cross-sectional views and top views in order to make the configuration easier to understand. . 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 absorption unit 10 of the present embodiment includes an expandable spring 12 and a fixing device arranged around the spring 12 to prevent the spring 12 from expanding or contracting. It has a member 14. When an impact larger than a predetermined threshold value is applied to the impact absorption unit 10, the fixing member 14 breaks, thereby absorbing the impact applied to the impact absorption unit 10. Furthermore, 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, which will be 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 breaks into the breaking portion 18. It is designed to break along the line (see Figure 5).

Moreover, the spring 12 is comprised of a substantially cylindrical push spring, and the said spring 12 can expand and contract along the longitudinal direction (namely, along the left-right direction in FIG. 2). Here, a compression spring generally refers to a structure in which each coil portion is wound so that a gap exists between each coil forming the spring portion (in other words, the spring portion can be compressed along the longitudinal direction). It is something that In the example shown in FIG. 1 and the like, the spring 12 is fixed by a fixing member 14 in a compressed state along the longitudinal direction so that each coil portion is tightly attached. Further, substantially S-shaped hooks 13 are provided at both ends of the spring 12 as attachment members. Specifically, the spring 12 is formed so that the outer diameter becomes smaller near both ends of the spring 12, and the substantially S-shaped hook 13 is installed so that one end thereof is located inside the spring 12. ing. Each hook 13 allows the shock absorption unit 10 to be attached to a wire main body 330 of a rockfall prevention system 300, which will be described later (see FIG. 20). Further, the spring 12 is made of hard steel wire, piano wire, 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 substantially cylindrical sleeve, and a fixed part 15 and an open part 16 are formed inside each of the fixing members 14. . Specifically, the fixing portions 15 are provided at both ends of the fixing member 14, and are configured so as not to allow the spring 12 to stretch when the fixing member 14 is broken along the breaking portion 18. . More specifically, as shown in FIGS. 4 and 5, the fixed portion 15 has a shape that follows 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. It is located. Therefore, even if the hooks 13 of the shock absorbing unit 10 are pulled apart from each other and the fixing member 14 is broken along the breaking portion 18, the portion of the spring 12 that is in contact with the fixing portion 15 is It is designed so that it does not extend from the state shown in 4. On the other hand, the open portion 16 is provided at the center of the fixing member 14 and is configured to allow the spring 12 to stretch when the fixing member 14 is broken along the breaking portion 18. In more detail, as shown in FIG. 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 comprised of a generally 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 break portion 18, and the fixing member 14 is configured to break along the break portion 18. Specifically, when an impact is applied to each hook 13 provided at both ends of the spring 12 in a direction that moves them away from each other, and the magnitude of this impact is greater than a predetermined threshold, the fixing member 14 A break is made along the break portion 18. In the example shown in FIG. 1 and the like, the broken portion 18 is a groove having a substantially V-shaped (wedge-shaped) cross section. Furthermore, the fracture portion 18 is formed approximately at the center of the cylindrical open portion 16 and extends all around the circumferential direction.

Specifically, when a shock larger than a predetermined threshold 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 breakage portion 18 as shown in FIG. . Due to such breakage of the fixing member 14, a portion of the impact applied to the impact absorption 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, when the fixing member 14 breaks, the spring 12 is allowed to stretch. Further, when the spring 12 is allowed to stretch, the spring 12 stretches, and the shock applied to the shock absorbing unit 10 is further absorbed. In this way, the shock absorbing unit 10 absorbs shocks by breaking the fixing member 14 and expanding and contracting the springs 12, and therefore can absorb shocks more effectively than a structure that absorbs shocks by friction.

Furthermore, by changing the shape of the breaking portion 18 formed in the fixing member 14, it is possible to adjust the threshold value of the magnitude of the impact when the fixing member 14 breaks. For example, if the depth of the groove in the broken portion 18 is made shallower from the state shown in FIG. can be made larger. On the other hand, if the depth of the groove of the broken part 18 is increased from the state shown in FIG. can be made smaller. With this, it is possible to manufacture the shock absorption unit 10 that absorbs shocks of various sizes.

Furthermore, 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 portion of the fixing member 14 in the circumferential direction. Further, the cross-sectional shape of the broken portion provided in the fixing member 14 may be approximately U-shaped, a concave shape, a depression, or the like. In other words, the broken portion may have any shape as long as the portion of the fixing member 14 where the broken portion 18 is formed has a lower strength than other portions of the fixing member 14 .

In addition, when the breaking portion 18 is formed over the entire circumferential direction of the fixing member 14 and has a substantially V-shaped cross section, the breaking load of the fixing member 14 can be calculated by a known method. Therefore, the above-mentioned predetermined threshold value can be determined by calculation, and therefore, the shock absorption unit 10 having the desired predetermined threshold value can be easily designed. Furthermore, even in cases where the shape of the fracture portion 18 is complex and the fracture load of the fixing member 14 cannot be easily calculated, it is possible to create a shock absorbing unit 10 with a desired threshold by making and evaluating a prototype. can be created.

Moreover, instead of adjusting the threshold value of the magnitude of the impact when the fixing member 14 breaks by changing the shape of the breaking portion 18, or in addition to changing the shape of the breaking portion 18, the following method may be used. The shock magnitude threshold may be adjusted depending on the method. Specifically, by changing the material constituting the fixing member 14, the threshold value of the magnitude of the impact when the fixing member 14 breaks may be adjusted. In this manner, when the materials are different, it is possible to adjust the threshold value of the magnitude of the impact when the fixing member 14 breaks even when the fixing member 14 is molded into substantially the same shape. Specifically, as the material of the fixing member 14, carbon steel, stainless steel, aluminum alloy, copper, brass, titanium, plastic, etc. can be used. For example, the threshold for the magnitude of impact when the fixing member 14 made of carbon steel breaks is greater than the threshold for the magnitude of the impact when the fixing member 14 made of plastic breaks. Become.

Furthermore, as other examples of the shock absorbing unit 10 of this embodiment, those shown in FIGS. 6 to 8 may be used. FIGS. 6 to 8 are explanatory diagrams for explaining the configuration of other examples of the shock absorbing unit of the present invention. As mentioned above, in FIGS. 6 to 8 as well, the fixing member is shown in cross-sectional view, while the spring and the mounting member are shown in top view.

The shock absorbing unit 20 shown in FIGS. 6 to 8 includes an expandable spring 22 and a fixing member 24 that is arranged around the spring 22 and fixes the spring 22 so that it does not expand or contract. . Furthermore, when a shock larger than a predetermined threshold is applied to the shock absorbing unit 20, a part of the fixing member 24 (specifically, a knock pin 28a, which will be described later) breaks, so that the impact is applied to the shock absorbing unit 20. It is designed to absorb shock.

Specifically, the spring 22 is constituted by a substantially cylindrical push spring, and the spring 22 can be expanded and contracted 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 a fixing member 24 in a compressed state along the longitudinal direction so that each coil portion is 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, respectively. Each attachment member 23 allows the shock absorption unit 20 to be attached to a wire body 330 of a rockfall prevention system 300, which will be described later (see FIG. 20). Further, the spring 22 is made of hard steel wire, piano wire, stainless steel wire, or the like.

As shown in FIG. 6 and other figures, 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 cylindrical members 24a, 24b (i.e., a first accommodating portion and a second accommodating portion) and a sleeve 24c disposed around the cylindrical members 24a, 24b. and knock pins 28a, 28b (ie, maintenance portions). Further, the spring 22 is arranged inside the pair of cylindrical members 24a and 24b. In other words, a part of the spring 22 is accommodated inside one cylindrical member 24a, and a part of the spring 22 is also accommodated inside the other cylindrical member 24b. ing.

Further, the cylindrical members 24a and 24b are provided with substantially circular openings 27a and 27b, respectively. Further, the sleeve 24c is also provided with two approximately circular openings 27c. Then, each cylindrical member 24a, 24b and sleeve 24c are installed so that each opening 27a, 27b and each opening 27c are opposed to each other. Thereafter, the substantially cylindrical knock pin 28a is inserted into each opening 27a, 27c, and the substantially cylindrical knock pin 28b is inserted into each opening 27b, 27c. The respective knock pins 28a and 28b serving as such maintenance portions maintain the respective cylindrical members 24a and 24b so that they do not move relative to each other. In this way, the shock absorbing unit 20 is assembled.

Each of the cylindrical members 24a and 24b has a first outer diameter, and a first portion on the side where the mounting member 23 is provided and a second outer diameter larger than the first outer diameter. and a second portion having a second portion. Further, fixed portions 25a and 25b are formed inside the first portions of each of the cylindrical members 24a and 24b, respectively, so as not to allow the spring 22 to stretch when the knock pin 28a is broken.

More specifically, as shown in FIG. 6 etc., each fixed portion 25a, 25b has a shape that follows the contour of the spring 22, and the inner surface of each fixed portion 25a, 25b and the outer surface of the spring 22 are placed in contact with each other. Therefore, even if the mounting members 23 of the shock absorbing unit 20 are pulled apart from each other and the knock pin 28a breaks along the broken portion, the portions of the spring 22 that are in contact with the fixed portions 25a and 25b are It is designed not to extend from the state shown in FIG. In this case, the broken portion is located near the portion of the knock pin 28a where the cylindrical member 24a and the sleeve 24c are in contact. On the other hand, open portions 26a and 26b are formed inside the second portions of the respective cylindrical members 24a and 24b, respectively, to allow the spring 22 to expand when the knock pin 28a is broken. 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. Further, when the spring 22 is housed inside each cylindrical member 24a, 24b, the spring 22 and each open portion 26a, 26b are prevented from coming into contact with each other. Specifically, the open portions 26a and 26b of each of the cylindrical members 24a and 24b are 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 right knock pin 28a has a shear stress of 5 KN, and the left knock pin 28b has a shear stress of 20 KN. For this reason, when an impact larger than a predetermined threshold is applied to the impact absorption unit 20, the knock pin 28a is first broken and the spring 22 is allowed to expand (see FIG. 8). Due to such breakage of the knock pin 28a, a portion of the impact applied to the impact absorption unit 20 is absorbed. As described above, the knock pin 28a is designed to break near the point where the cylindrical member 24a and the sleeve 24c are in contact, and in the shock absorbing unit 20 shown in FIG. 6 etc., this point is fixed. This corresponds to the broken part of the member 24.

Further, as described above, since the open portions 26a and 26b of each of the cylindrical members 24a and 24b are not in contact with the spring 22, the spring 22 is allowed to expand when the knock pin 28a breaks. Further, when the spring 22 is allowed to stretch, the spring 22 stretches, and the shock applied to the shock absorbing unit 10 is further absorbed. In this way, the shock absorbing unit 20 absorbs shock by breaking the knock pin 28a and expanding and contracting the spring 22, and therefore can absorb the shock more effectively than a structure that absorbs the shock by friction. Moreover, if a further impact is applied to the shock absorbing unit 20 after the knock pin 28a breaks, the knock pin 28b will also break.

Further, although an example has been described in which the right knock pin 28a has a shear stress of 5KN and the left knock pin 28b has a shear stress of 20KN, the present invention is not limited to such a configuration. Dowel pins 28a and 28b having shear stress values different from those described above may be used, or knock pins 28a and 28b having substantially the same shear stress may be used, respectively. Note that even if the impact absorption units 20 have substantially the same shape, by using knock pins 28a and 28b with different configurations, the threshold value of the magnitude of the impact when the knock pins 28a and 28b of the impact absorption unit 20 break can be adjusted. can be adjusted. Specifically, by changing the material and diameter of each knock pin 28a, 28b, it is possible to adjust the threshold value of the magnitude of the impact when each knock pin 28a, 28b breaks.

Note that the number of openings 27a, 27b provided in each cylindrical member 24a, 24b is not limited to one, and two or more openings 27a, 27b may be provided in each cylindrical member 24a, 24b, respectively. You can leave it there. In this case, the sleeve 24c has the same number of openings 27c as the total number of openings 27a and 27b provided in each of the cylindrical members 24a and 24b. In other words, the sleeve 24c has the same number of openings 27c as the total number of openings 27a and 27b provided in each of the cylindrical members 24a and 24b. Further, knock pins are arranged to pass through each of the openings 27a, 27b, and 27c.

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

The shock absorption unit 100 shown in FIGS. 9 to 13 includes an expandable spring 120 and a fixing member 130 that is arranged around the spring 120 and fixes the spring 120 so that it does not expand or contract. . In addition, when a shock larger than a predetermined threshold is applied to the shock absorbing unit 100, a part of the fixing member 130 (specifically, a rod-shaped member 152, which will be described later) breaks, causing the impact absorbing unit 100 to be damaged. It is designed to absorb the shock caused by the impact.

Specifically, the spring 120 is constituted by a substantially cylindrical push spring, and the spring 120 can be expanded and contracted 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 a fixing member 130 in a compressed state along the longitudinal direction so that each coil portion is 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. The shock absorbing unit 100 can be attached to a wire main body 330 of a rockfall prevention system 300, which will be described later, using the attachment parts 110a and 110b (see FIG. 20). Further, the spring 120 is made of hard steel wire, piano wire, stainless steel wire, or the like.

As shown in FIG. 9 and other figures, the fixing member 130 of the shock absorbing unit 100 is made up of a combination of a plurality of members. Specifically, the fixing member 130 includes a pair of cylindrical members 130a and 130b (i.e., a first housing part and a second housing part), and an inner housing 140a installed inside the substantially cylindrical spring 120. , 140b, and a maintenance portion 150. Further, the spring 120 is arranged inside the pair of cylindrical members 130a and 130b. More specifically, part of the spring 120 is housed inside one cylindrical member 130a, and the remaining part of the spring 120 is housed inside the other cylindrical member 130b. In this embodiment, each cylindrical member 130a, 130b and each inner housing 140a, 140b are configured to contact each other at approximately the center of the spring 120 in the length direction. This state is maintained by the maintenance portion 150.

Next, a configuration in which the cylindrical members 130a and 130b are maintained so that they do not move relative to each other by the maintenance portion 150 will be described with reference to FIGS. 9 to 12. Note that the configurations of each mounting portion 110a, 110b, each cylindrical member 130a, 130b, and each inner housing 140a, 140b are substantially the same. Therefore, in the following, the configuration of one member (the member on the left side in FIG. 9) will be described in detail, and the description of the configuration of the other member (the member on the right side in FIG. 9) may be omitted.

The attachment portion 110a includes an attachment portion 111a to which a wire main body 330 of a rockfall prevention system 300, which will be described later, is attached, an intermediate portion 114a, and a threaded portion 116a in which an attachment portion such as a male thread is formed. Further, the intermediate portion 114a is provided between the mounting portion 111a and the threaded portion 116a, and is formed to have approximately the same outer diameter as the opening 132a (see FIG. 11) formed in the cylindrical member 130a. There is. Further, the threaded portion 116a is formed to have a smaller outer diameter than the intermediate portion 114a. Therefore, the threaded portion 116a of the attachment portion 110a can be passed through the opening 132a of the cylindrical member 130a. In this state, a washer 117a and a nut 118a having an outer diameter larger than the opening 132a of the cylindrical member 130a are attached to the threaded portion 116a. This allows the attachment portion 110a to be fixed to the cylindrical member 130a (see FIG. 12). Note that an accommodating portion 142a is formed in an inner housing 140a disposed inside the spring 120. This makes it possible to prevent interference between the mounting part 110a and the inner housing 140a when the mounting part 110a, the cylindrical member 130a, and the inner housing 140a are assembled as shown in FIG. It has become.

Furthermore, a counterbore hole 112a and a through hole 119a having a smaller diameter than the counterbore hole 112a are formed in the mounting portion 110a, and a rod-shaped member 152 of the maintenance portion 150 is installed inside the through hole 119a. It has become. Further, threaded portions (not shown) for attaching nuts 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, by attaching the nut 154a to the threaded portion of the bar member 152 after arranging the bar member 152 inside the counterbored hole 112a and the through hole 119a, the bar member 152 and the nut 154a may come off from the through hole 119a. can be prevented.

Further, as shown in FIG. 9, the rod-shaped member 152 has a value that is the sum of the depth (length) of the through holes 119a, 119b of each mounting portion 110a, 110b, and the length of each cylindrical member 130a, 130b. Those with larger lengths are now being used. For this reason, each nut 154a, 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 each of the through holes 119a, 119b and each cylindrical member 130a, 130b. Moreover, this makes it possible to maintain the one cylindrical member 130a and the other cylindrical member 130b so that they do not move relative to each other. Note that, as shown in FIG. 11 etc., since the inner housing 140a is provided with a through hole 144a, interference between the rod-shaped member 152 of the maintenance portion 150 and the inner housing 140a is prevented. ing.

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

Moreover, fixed parts 134a, 134b and open parts 136a, 136b are provided inside the cylindrical members 130a, 130b, which are arranged around the spring 120 and serve as a first housing part and a second housing part, respectively. It is formed. Further, each fixed portion 134a, 134b is configured not to allow the spring 120 to stretch when the rod-shaped member 152 of the maintenance portion 150 is broken. Specifically, as shown in FIG. 9 etc., the inner peripheral surface of each fixed portion 134a, 134b has a shape that follows the contour of the spring 120, and the inner surface of each fixed portion 134a, 134b and the spring 120 are arranged so that the outer surfaces thereof are in contact with each other. On the other hand, each open portion 136a, 136b is configured so that it does not come into contact with the spring 120 when the spring 120 is accommodated inside each cylindrical member 130a, 130b. For this reason, when the rod-shaped member 152 of the maintenance portion 150 is broken, the portions of the spring 120 facing the respective open portions 136a, 136b are allowed to elongate. Specifically, the open portions 136a and 136b of each of the cylindrical members 130a and 130b are substantially cylindrical portions having an inner diameter larger than the outer diameter of the spring 120.

Furthermore, fixed portions 146a, 146b and open portions 148a, 148b are formed on the outside of each inner housing 140a, 140b located inside the substantially cylindrical spring 120, respectively. Furthermore, the fixed portions 146a and 146b do not allow the spring 120 to stretch when the rod-shaped member 152 of the maintenance portion 150 breaks. Specifically, as shown in FIG. 9 etc., the outer circumferential surface of each fixed portion 146a, 146b has a shape that follows the contour of the spring 120, and the outer circumferential surface of each fixed portion 146a, 146b and the spring 120 are arranged so that their inner peripheral surfaces are in contact with each other. On the other hand, each open portion 148a, 148b is configured not to contact spring 120 when each inner housing 140a, 140b is housed within spring 120. Therefore, when the rod-shaped member 152 of the maintenance portion 150 is broken, the portions of the spring 120 facing the respective open portions 148a and 148b are allowed to elongate. Specifically, the open portions 148a, 148b of each inner housing 140a, 140b are formed from generally cylindrical portions having an outer diameter smaller than the inner diameter of the spring 120.

As described above, the rod-shaped member 152 of the impact absorption unit 100 is configured to break when an impact larger than a predetermined threshold is applied to the impact absorption unit 100. Due to such breakage of the rod-shaped member 152, a portion of the impact applied to the impact absorption unit 100 is absorbed. Moreover, when the rod-shaped member 152 breaks, the force for maintaining the respective cylindrical members 130a and 130b from moving relative to each other ceases to work, so that the spring 120 is allowed to stretch. Furthermore, when the spring 120 is allowed to stretch, the spring 120 stretches, and the shock applied to the shock absorption unit 100 is further absorbed (see FIG. 13). In this way, the shock absorbing unit 100 absorbs shocks by breaking the rod-shaped member 152 and expanding and contracting the springs 22, and therefore can absorb shocks more effectively than a structure that absorbs shocks by friction. Further, the shock absorbing unit 100 can be used again simply by replacing the broken rod-like member 152 with a new rod-like member 152, so that convenience for the user can be improved.

Note that the rod-shaped member 152 of the maintenance portion 150 shown in FIG. 9 etc. is rod-shaped with a predetermined diameter and does not have a broken portion, but the present invention 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 portion of the rod-shaped member 152 or by providing a recess or a notch. Furthermore, by changing the diameter and material of the rod-like member 152, the threshold value of the impact when the rod-like member 152 breaks may be adjusted.

Note that, as described above, the configurations of the attachment portion 110a, each cylindrical member 130a, and the inner housing 140a are substantially the same as the configurations of the attachment portion 110b, the cylindrical member 130b, and the inner housing 140b. In other words, the mounting portion 110b includes a mounting portion 111b, a counterbore hole 112b, an intermediate portion 114b, a threaded portion 116b, a washer 117b, a nut 118b, and a through hole 119b. Moreover, the cylindrical member 130b further has an opening 132b. In addition, the inner housing 140b further includes a housing portion 142b and a through hole 144b.

Moreover, the installation of each inner housing 140a, 140b may be omitted. Note that when each inner housing 140a, 140b is additionally installed, the spring 120 connects to the fixed portions 134a, 134b of each cylindrical member 130a, 130b, and the fixed portions 146a, 146b of each inner housing 140a, 140b. become caught 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 deforming.

In addition, in the example shown in FIG. 9, etc., the first cylindrical member and the second cylindrical member have approximately the same length, and each inner housing has approximately the same length. Although the mode of use has been described, it is not limited to such a configuration. For example, a first cylindrical member and a second cylindrical member having different lengths or inner housings may be used.

Further, as other examples of the shock absorbing unit 10 of this embodiment, those shown in FIGS. 14 to 17 may be used. 14 to 17 are an explanatory diagram, a top view, and a sectional view, respectively, for explaining the configuration of still another example of the shock absorbing unit of the present invention. Here, FIGS. 15 and 16 are a top view and a sectional view, respectively, for explaining the configuration of still another example of the shock absorption unit. Further, FIGS. 14 and 17 are explanatory diagrams depicting the shock absorption unit by combining a sectional view and a top view for the purpose of making the configuration easier to understand.

The shock absorption unit 200 shown in FIGS. 14 to 17 includes an expandable spring 220 and a fixing member 230 for fixing the spring 220 so that it does not expand or contract. More specifically, the spring 220 has a substantially cylindrical shape, and the fixing member 230 is arranged inside the spring 220. Furthermore, when a shock larger than a predetermined threshold is applied to the shock absorbing unit 200, the fixing member 230 (specifically, the breaking portion 238) breaks, thereby absorbing the shock applied to the shock absorbing unit 200. It is supposed to be done.

Specifically, the spring 220 is constituted by 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 a fixing member 230 in a compressed state along the longitudinal direction so that each coil portion is in close contact with each other. Further, the spring 220 is made of hard steel wire, piano wire, stainless steel wire, or the like.

Further, as shown in FIG. 15 and the like, attached parts 232 such as internal threads are formed at both ends of the fixing member 230, and the attachment parts 210 are attached to these attached parts 232, respectively. There is. Further, each attachment portion 210 allows the shock absorption unit 200 to be attached to a wire main body 330 of a rockfall prevention system 300, which will be described later. In addition, in the example shown in FIG. 14 etc., each attachment part 210 is equipped with the substantially U-shaped attachment part 212. Furthermore, the attachment portion 212 is rotatable relative to the fixing member 230 about an axis along the direction in which the spring 220 extends (that is, the left-right direction in FIG. 14). Furthermore, the mounting portion 212 is rotatable relative to the fixed 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 becomes.

Further, the fixing member 230 is formed with a sealing member attachment portion 233, a fixing portion 234, an open portion 236, and a breakage portion 238, respectively. As will be described later, sealing members 264 and 266 such as O-rings are attached to each sealing member attachment portion 233. Additionally, each fixed portion 234 is configured to not allow the spring 220 to stretch when the breakable portion 238 breaks. Specifically, the outer circumferential surface of each fixed portion 234 has a shape that follows the contour of the inner circumferential surface of the spring 220, and the outer circumferential surface of each fixed member 230 and the inner circumferential surface of the spring 220 are aligned with each other. They are arranged so that they are in contact with each other. On the other hand, the open portion 236 is configured so as not to come into contact with the spring 220 when each fixing member 230 is housed inside the spring 220. Therefore, when the broken portion 238 of the fixing member 230 breaks, the spring 220 is allowed to stretch. Specifically, the open portion 236 of the fixing member 230 is comprised of a substantially cylindrical portion having an outer diameter smaller than the inner diameter of the spring 220.

Further, in the shock absorbing unit 200, when a shock larger than a predetermined threshold 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 Figure 17). By breaking the fixing member 230 in this manner, a portion of the impact applied to the impact absorption unit 200 is absorbed. Further, when the fixing member 230 is broken, the force for maintaining the state shown in FIG. 14 is no longer exerted, so that the spring 220 is allowed to stretch. Furthermore, when the spring 220 is allowed to stretch, the spring 220 stretches, and the shock applied to the shock absorption unit 200 is further absorbed. In this way, the shock absorbing unit 200 absorbs shocks by breaking the fixing member 230 and expanding and contracting the springs 220, and therefore can absorb shocks more effectively than a structure that absorbs shocks by friction.

Note that the broken portion 238 is the part of the fixing member 230 with the smallest diameter, and in the example shown in FIG. Further, the breaking load (tensile stress) of the breaking portion 238 can be calculated by a known method based on the material of the fixing member 230, the diameter of the breaking portion 238, and the like. Further, by changing the material of the fixing member 230 and the diameter of the breaking portion 238, it is possible to adjust the threshold value of the magnitude of the impact when the breaking portion 238 breaks. Furthermore, the broken portion 238 may be formed at a location other than approximately the center in the extending direction of the fixing member 230.

As shown in FIGS. 14, 16, etc., the shock absorption unit 200 includes a protective member disposed around the spring 220, and a sealing member disposed at a position in contact with the protective member to liquid-tightly seal the spring 220. members 262, 264, and 266. Specifically, the protection member is composed of a combination of a first cylindrical member 240 and a second cylindrical member 250. Further, the spring 220 is arranged inside the first cylindrical member 240 and the second cylindrical member 250. More specifically, part of the spring 220 is housed inside the first cylindrical member 240, and the remaining part of the spring 220 is housed inside the second cylindrical member 250. There is.

Further, an opening 242 is formed in the first cylindrical member 240, and one end of the fixing member 230 (specifically, one attached part 232) is connected to the first cylindrical member 240 through this opening 242. It is exposed to the outside of the cylindrical member 240. Further, an opening 252 is formed in the second cylindrical member 250, and the other end of the fixing member 230 (specifically, the other attached part 232) is connected to the second cylindrical member 250 through this opening 252. It is exposed to the outside of the cylindrical member 250. The attachment portions 210 are attached to each attached portion 232 of the fixing member 230 that is exposed to the outside.

Further, near the end of the first cylindrical member 240 opposite to the opening 242, a sealing member is attached, which is a recess formed along the entire circumference of the first cylindrical member 240. A portion 248 is formed. Further, an extending portion 258 having an outer diameter larger than the outer diameter of the end of the first cylindrical member 240 is provided near the end of the second cylindrical member 250 on the opposite side from the opening 252. There is. Further, the extending portion 258 of the second cylindrical member 250 is connected to the first cylindrical member 250 when the first cylindrical member 240 and the second cylindrical member 250 are combined to be in the state shown in FIG. The length is formed to cover a region of the shaped member 240 including the sealing member attachment portion 248. Therefore, by attaching a sealing member 262 such as an O-ring to the sealing member attachment portion 248 of the first cylindrical member 240, contact between the first cylindrical member 240 and the second cylindrical member 250 is prevented. It is possible to prevent the spring 220 from getting wet due to liquid such as water entering the spring 220 (see FIG. 14).

In addition, sealing members 262 and 264 such as O-rings are installed in each sealing member mounting portion 233 which is a recess formed along the entire circumference of the fixing member 230 in the circumferential direction. As shown in FIG. 14, a sealing member 264 is attached between the sealing member attachment part 233 provided at one end of the fixing member 230 and the first cylindrical member 240. ing. Further, a sealing member 266 is attached between the other sealing member attaching portion 233 formed on the fixing member 230 and the second cylindrical member 250. These sealing members 262 and 264 prevent the spring 220 from getting wet even when liquid such as water enters through the opening 242 of the first cylindrical member 240 or the opening 252 of the second cylindrical member 250. This can be prevented.

Further, fixed portions 244 and 254 and open portions 246 and 256 are formed inside the first cylindrical member 240 and the second cylindrical member 250, respectively. Specifically, each securing portion 244, 254 is configured to not allow the spring 220 to stretch when the fracture portion 238 of the securing member 230 breaks. As shown in FIG. 14 and the like, the inner circumferential surface of each fixed portion 244, 254 has a shape that follows the contour of the spring 220, and the inner circumferential surface of each fixed portion 244, 254 and the outer circumference of the spring 220. The surfaces are arranged so that they are in contact with each other. On the other hand, each open portion 246, 256 is configured not to contact the spring 220 when the spring 220 is housed inside the first cylindrical member 240 and the second cylindrical member 250. Therefore, when the broken portion 238 of the fixing member 230 breaks, the spring 220 is allowed to stretch. Specifically, each of the open portions 246 and 256 of the first cylindrical member 240 and the second cylindrical 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 a grease injection port for injecting grease may be formed in the first cylindrical member 240 and the second cylindrical member 250 of the above-described shock absorbing unit 200, respectively. In this case as well, by attaching a cap of a corresponding shape to each grease injection port, it is possible to prevent liquid such as water from entering from the grease injection port.

Here, a conventional shock absorbing unit 50 is shown in FIG. In the shock absorbing unit 50 of the prior art, a portion of the wire body 52 is wound in an annular shape so as to overlap in the radial direction, and the overlapping portion is caulked by a 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 bodies 52 and the frictional force acting between the wire bodies 52 and the tightening member 54. . In other words, when a shock is absorbed, the size of the annular portion of the wire body 52 becomes smaller. In contrast, in the shock absorbing units 10, 20, 100, 200 according to the present embodiment, the fixing members 14, 24, 152, 230 are broken as described above. The shock is absorbed by expanding and contracting the springs 12, 22, 120, and 220. Therefore, it is possible to achieve a higher impact absorption effect than the conventional technology that absorbs impact by friction. Further, even if a shock smaller than the above-mentioned predetermined threshold is applied to the shock absorbing units 10, 20, 100, 200, the fixing members 14, 24, 152, 230 are prevented from breaking. Therefore, compared to the conventional technology in which the wires tend to stretch even with a small impact, it is possible to extend the intervals between maintenance and replacement of the shock absorption units 10, 20, 100, and 200. , 200 can be improved. Further, it is possible to prevent the broken fixing members 14, 24, 152, 230 from scattering.

Note that when using the above-mentioned push springs as the springs 12, 22, 120, 220, the configuration is limited to fixing the springs 12, 22, 120, 220 in a compressed state with the fixing members 14, 24, 152, 230. It will not be done. It is also possible to fix springs 12, 22, 120, 220 with uncompressed coil portions such that there is a gap between each coil portion by the fixing members 14, 24, 152, 230. Alternatively, as the springs 12, 22, 120, 220, substantially cylindrical tension springs (tension coil springs) may be used instead of the above-mentioned push springs. Here, a tension spring (tension coil spring) is one in which each coil part is wound in advance in a state in which each coil part is closely attached so that there is generally no gap between the coils forming the spring part.

Next, as an example of a rockfall prevention system using the shock absorption units 10, 20, 100, and 200 of this embodiment, a rockfall prevention system 300 equipped with the shock absorption 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. In addition, although the rockfall prevention system 300 including the impact absorption unit 10 will be described below, the rockfall prevention system may be configured using the impact absorption units 20, 100, and 200 instead of the impact absorption unit 10.

The rock fall prevention system 300 shown in FIGS. 19 and 20 is installed on a slope 400 of a mountain or the like, so that fallen objects such as stones that fall from the mountain side toward the valley side along the slope 400 (for example, as shown in FIG. It is used to receive signals (indicated by reference numeral D). The rockfall prevention system 300 also includes a support 310, a falling object receiving member 320 stretched between each support 310, a wire body 330 stretched between the support 310 and the slope 400 on the mountain side, and a wire body 330 stretched between the support 310 and the slope 400 on the mountain side. 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 members 320 stretched over each column 310 are configured to catch falling objects falling along the slope 400. It has become. The impact when a falling object is caught by the falling object receiving member 320 is absorbed by the shock absorbing unit 10 and the like.

Further, the wire main body 330 is composed of a plurality of wire parts, and an annular member is provided at the end of each wire part as a connecting member for connecting the wire part and the shock absorption unit 10. The wire main body 330 and the shock absorbing unit 10 are connected by inserting the tip of each hook 13 of the shock absorbing unit 10 into the annular member of each wire portion. Note that each wire portion of the wire body 330 and each hook 13 of the shock absorption 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 body 330. Note that when the rockfall prevention system 300 is configured using the shock absorbing units 20, 100, and 200, appropriate connecting members are separately provided on each wire portion of the wire body 330.

Furthermore, in the rockfall prevention system 300 shown in FIG. 19 and the like, a plurality of (specifically, two) shock absorption units 10 are connected in series to one wire main body 330 made up of a plurality of wire parts. In this embodiment, shock absorbing units 10 are used that have different threshold values for the magnitude of the impact at which the fixing member 14 breaks when an impact is applied to the impact absorbing unit 10. According to such a configuration, the rockfall prevention system 300 can appropriately absorb impacts of various sizes. As an example, each of the shock absorbing units 10 including the fixing member 14 having a first value of the above-mentioned impact magnitude threshold, and a second value having the above-mentioned impact magnitude threshold larger than the first value. Consider a case in which a shock absorbing unit 10 equipped 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, one of the impact absorption units whose impact magnitude threshold is the first value Only the fixing member 14 of the unit 10 will break. On the other hand, when a shock larger than the sum of the first value and the second value is applied to each shock absorbing unit 10, the fixing members 14 of both shock absorbing units 10 break, respectively. 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 14 comes to break.

Note that the number of shock absorbing units 10 connected to one wire main body 330 consisting of a plurality of wire portions is not limited to two. Only one shock absorption unit 10 may be connected to one wire body 330, or three or more shock absorption units 10 may be connected to one wire body 330. Alternatively, 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 absorption unit 10 may be used so as to be directly lined up.

Further, each of the pillars 310 is installed at substantially the same height level when viewed from the slope 400 via each base member 312 fixed to the slope 400. Moreover, as shown in FIG. 20, each support 310 and each base member 312 are connected, for example, by a hinge 314 that opens on both sides. Therefore, each support 310 can be swung relative to each base member 312 (ie, slope 400) (see arrow A in FIG. 20). This makes it possible to reduce the stress that acts on each support column 310 when a falling object is caught by the falling object receiving member 320. Note that 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.

Furthermore, 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 catching falling objects. Note that, for example, a fence made of metal rods and plates, or a ring-shaped net may be used as the falling object receiving member.

Here, as a conventional rock fall prevention system, by allowing the wire connected to the falling object receiving member to elongate as shown in Figure 18, when a falling object is caught by the falling object receiving member, the wire is It is known that a shock absorbing unit is used to absorb the shock caused by the shock. However, in the above configuration, the wire stretches even when the magnitude of the applied impact is small, and because the wire tends to stretch even with a small impact, there is a problem that the wire needs to be maintained at relatively short intervals. there were. On the other hand, according to the rockfall prevention system 300 according to the present embodiment, the shock absorption unit 10 is used which absorbs a shock only when a shock larger than a predetermined threshold is applied. This makes it possible to reduce the effort required to maintain the rockfall prevention system 300.

In addition, since the wire body 330 and the shock absorption unit 10 of the rockfall prevention system 300 are installed in a substantially linearly extending state, an adverse effect on the wire body 330 is suppressed after the fixing member 14 of the shock absorption unit 10 breaks. It is now possible to do so. That is, in a conventional shock absorbing unit 50 as shown in FIG. 18, the wire main body 52 is wrapped once in an annular shape and is caulked by a tightening member 54. Therefore, even after the impact absorption unit 50 absorbs the impact (that is, after the annular portion has shrunk), the wire main body 52 remains in the 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 will be applied to the area where the wire body 52 and the tightening member 54 are in contact, and the wire body 52 may break from that area. There is sex. In contrast, in the present embodiment, the wire main body 330 and the shock absorption unit 10 are installed in a substantially linearly extending state, so that the above-mentioned problem can be prevented from occurring. be able to. Further, it is possible to prevent the wire main body 330 from being twisted after the fixing member 14 of the shock absorbing unit 10 is broken.

The shock absorption units 10, 20, 100, 200 for absorbing shock, which have the above-described configuration, have expandable and contractible springs 12, 22, 120, 220, and fixing springs 12, 22, 120, 220. It has fixing members 14, 24, 130, 230 for. The fixing members 14, 24, 130, 230 break when the magnitude of the impact applied to the impact absorbing units 10, 20, 100, 200 is larger than a predetermined threshold. In this way, the fixing members 14, 24, 130, 230 break and the springs 12, 22, 120, 220 expand and contract only when an impact greater than a predetermined threshold is applied. Therefore, it is possible to absorb the impact when the fixing members 14, 24, 130, 230 break. Furthermore, since the fixing members 14, 24, 130, and 230 absorb shock by breaking, the shock can be absorbed more effectively than a structure that absorbs shock by friction. Further, in the shock absorbing units 10, 20, 100, 200, the springs 12, 22, 120, 220 are push springs or tension springs. Further, when a compression spring is used as the spring 12, 22, 120, 220, the fixing member 14, 24, 130, 230 supports the spring 12, 22, 120, 220 in a compressed state along the longitudinal direction. It is designed to be fixed.

Furthermore, 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 and 238. Then, when the magnitude of the impact applied to the impact absorption units 10, 20, 100, 200 is larger than a predetermined threshold, the fixing members 14, 24, 152, 230 break along the breakage portions 18, 238. It looks like this. In this way, when the breaking portions 18, 238 are provided, it is possible to specify from which point the fixing members 14, 24, 152, 230 break. Convenience can be improved.

Furthermore, in the shock absorption unit 10 described above, the fixing member 14 is arranged around the spring 12, and a fixed part 15 and an open part 16 are formed inside the fixing members 14 and 24. . Further, the fixed portion 15 is configured not to allow the spring 12 to stretch when the fixed member 14 is broken. The open portion 16 also allows the spring 12 to stretch when the fixing member 14 breaks.

Furthermore, in the shock absorbing units 20, 100 described above, the fixing members 24, 130 have first housing portions 24a, 130a, second housing portions 24b, 130b, and a maintenance portion 150. Further, the first housing portions 24a, 130a are configured to store a portion of the springs 22, 120 inside, and the second housing portions 24b, 130b are configured to store a portion of the springs 22, 120 inside. It is designed to accommodate. Further, the maintenance portions 28a, 150 are configured to maintain the first housing portions 24a, 130a and the second housing portions 24b, 130b from moving relative to each other. The maintenance portions 28a, 150 are designed to break when the magnitude of the impact applied to the impact absorption units 20, 100 is greater than a predetermined threshold. Furthermore, inside the first housing parts 24a, 130a and the second housing parts 24b, 130b of the fixing members 24, 130, there are fixed parts 25a, 25b, 134a, 134b and open parts 26a, 26b, 136a, 136b. are formed respectively. Furthermore, the fixed parts 25a, 25b, 134a, 134b do not allow the springs 22, 120 to stretch when the maintenance parts 28a, 150 break. Additionally, the open portions 26a, 26b, 136a, 136b allow the springs 22, 120 to stretch when the retaining portions 28a, 150 break.

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

Further, in the shock absorption unit 200 described above, the fixing member 230 is arranged inside the spring 220. Furthermore, on the outside of the fixing member 230, there is a fixing 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. The shock absorption unit 200 also includes protective members (specifically, a first cylindrical member 240 and a second cylindrical member 250) disposed around the spring 220, and sealing members 262, 264, 266. It also has the following. Furthermore, each of the sealing members 262, 264, and 266 is arranged at a position in contact with the protection member, and is configured to seal the spring 220 in a liquid-tight manner. This prevents the spring 220 from getting wet or rusting, making it possible to suitably use the shock absorbing unit 200, for example, underwater.

Further, the rock fall prevention system 300 having the above configuration includes a plurality of support 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 shock absorbing It is equipped with units 10, 20, 100, and 200. More specifically, the falling object receiving member 320 is stretched around each support 310 and is adapted to catch falling objects falling along the slope 400. Further, the wire body 330 is stretched between each support 310 and the slope 400 on the mountain side, and the shock absorption units 10, 20, 100, and 200 are connected to the wire body 330. When the magnitude of the impact when a 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 shock can be absorbed more effectively than the conventional structure which absorbs the shock through friction. Moreover, the installation of the valley side wire (that is, the shock absorption units 10, 20 and the wire main body 330 disposed on the valley side) can be omitted, and the maintenance effort of the rockfall prevention system 300 can be reduced. In addition, the shock absorbing units 10, 20, 100, 200 have the magnitude of the impact that causes the fixing members 14, 24, 152, 230 to break when an impact is applied to the shock absorbing units 10, 20, 100, 200. A plurality of types with different threshold values are now used in series. This allows the rock fall prevention system 300 to appropriately absorb impacts of various sizes.

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

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

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

Further, as fixing members for fixing the springs 12, 22, 120, the fixing members 14, 24, 130, 230 shown in FIGS. 1, 6, 9, etc. have been described, but fixing members with other configurations may be used. You can do it like this. The fixing member may be a substantially cylindrical sleeve with an opening provided on the outer circumferential surface, or a substantially cylindrical sleeve with a slit (notch) extending from the upper end to the lower end. may be used. In this way, when openings or slits are provided in the fixing member, the states of the springs 12, 22, 120 can be checked from the outside, so maintenance of the shock absorption units 10, 20, 100 can be easily performed. You will be able to do this.

Further, fixing members 14, 24, 130, 230 having a different configuration from the examples shown in FIGS. 4, 6, 9, 14, etc. may be used. For example, the area of each fixed portion 15, 25a, 25b, 134a, 134b, 234 may be reduced from the state shown in FIG. 4, FIG. 6, FIG. 9, FIG. 14, etc. On the other hand, the area of each open portion 16, 26a, 26b, 136a, 136b, 236 may be increased. In this way, when the area of the open part is enlarged, the amount that the springs 12, 22, 120, 220 will expand when the fixing member breaks will increase, so the amount of expansion by the springs 12, 22, 120, 220 will be greater. can increase the amount of impact energy that can be produced.

Furthermore, although an example has been described in which the spring 12 and the hook 13 are made up of separate members as attachment members provided at both ends of the spring 12 of the shock absorption unit 10, attachment members of other shapes may be attached to the spring 12. It may be provided. For example, the end of the metal wire that constitutes the spring 12 may be formed into a substantially S-shape, a substantially U-shape, or a substantially V-shape, so that the spring and the mounting member are integrally molded. It's okay. Further, as the attachment members provided at both ends of the spring 22 of the shock absorbing unit 20, the above-mentioned hooks having a substantially S-shape, a substantially U-shape, or a substantially V-shape may be used.

Further, although an example has been described in which the breakage portion 18 is provided approximately at the center of the open portion 16 of the fixing member 14 of the shock absorbing unit 10, the breakage portion 18 is not limited to such a configuration. A breaking portion 18 may be provided at the bottom. In other words, if the breakage portion 18 is provided at any location in the open portion 16 of the fixing member 14, the impact absorption unit 10 can achieve the above-mentioned effects.

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

Further, each knock pin 28a, 28b of the shock absorbing unit 20 may be formed with a broken portion. For example, a groove having a substantially V-shaped cross section, such as the broken portion 18 of the shock absorbing unit 10 shown in FIG.

Further, it is not necessary to attach the shock absorption units 10, 20, 100, and 200 to all the pillars 310. When the strength of the rock fall prevention system is ensured, the shock absorption units 10, 20, 100, 200 are connected to the support 310 to which the wire body 330 to which the shock absorption units 10, 20, 100, 200 are connected is attached. The wire bodies 330 that are not attached may be arranged alternately with the columns 310 that are attached. Alternatively, a strut 310 to which the wire body 330 to which the shock absorption units 10, 20, 100, and 200 are connected is attached, and a strut to which the wire body 330 to which the shock absorption units 10, 20, 100, and 200 are not connected are attached. 310 may be arranged in a manner different from that described above.

Note that the use of the above-mentioned impact absorption units 10, 20, 100, and 200 is not limited to the above-mentioned rockfall prevention system 300. 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 absorption units 10 and 20 described above are used in seismic reinforcement work for bridge superstructures to prevent bridges from falling in the event of a large-scale earthquake, and seismic reinforcement work for bridge substructures in which bridge piers are reinforced with reinforced concrete. , 100, and 200 may be used. In this case, the earthquake resistance of the upper part of the bridge and the lower part of the bridge can be improved. Furthermore, the above-described impact absorption units 10, 20, 100, and 200 may be used as energy absorption devices in bridge collapse prevention systems. More specifically, when a large seismic force is applied to a bridge due to an earthquake, etc., it is used to limit the movement of girders relative to the substructure of the bridge, such as abutments, and to absorb the impact applied to the bridge. The shock absorbing units 10, 20, 100, and 200 described above may be used as the members. More specifically, the shock absorbing units 10, 20, 100, and 200 may prevent large displacements of the girders in the direction of the bridge axis or in a 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 this girder may be connected via the above-mentioned impact absorption units 10, 20, 100, and 200. Further, by using the shock absorbing units 10, 20, 100, 200 as guardrails or median strips, the shock when a vehicle or the like collides may be absorbed. Additionally, the shock absorbing units 10, 20, 100, 200 can be used for various other purposes.

10 Shock absorbing unit 12 Spring 13 Hook 14 Fixed member 15 Fixed part 16 Open part 18 Breaking part 20 Shock absorbing unit 22 Spring 23 Mounting member 24 Fixed member 24a, 24b Cylindrical member 24c Sleeve 25a, 25b Fixed part 26a, 26b Open part 27a, 27b, 27c Openings 28a, 28b Dowel pin 50 Shock absorbing unit 52 Wire body 54 Tightening member 100 Shock absorbing unit 110a, 110b Mounting parts 111a, 111b Mounting parts 112a, 112b Countersunk holes 114a, 114b Intermediate parts 116a, 116b Threaded part 117a , 117b Washers 118a, 118b Nuts 119a, 119b Through hole 120 Spring 130 Fixing member 130a Cylindrical member (first housing part)
130b Cylindrical member (second housing part)
132a, 132b Openings 134a, 134b Fixed parts 136a, 136b Open parts 140a, 140b Inner housings 142a, 142b Accommodating parts 144a, 144b Through holes 146a, 146b Fixed parts 148a, 148b Open part 150 Maintaining part 152 Rod-shaped member (one of the fixed members Department)
154a, 154b Nut 200 Shock absorption unit 210 Mounting part 212 Mounting part 220 Spring 230 Fixed member 232 Mounted part 233 Sealing member mounting part 234 Fixed part 236 Open part 238 Broken part 240 First cylindrical member 242 Opening 244 Fixed part 246 Open portion 248 Sealing member attachment portion 250 Second cylindrical member 252 Opening 254 Fixed portion 256 Open portion 258 Extension portions 262, 264, 266 Sealing member 300 Rockfall prevention system 310 Support column 312 Base member 314 Hinge 320 Fallen object receiver Stopping member 330 Wire body 400 Slope

Claims (11)

A shock absorption unit for absorbing shock,
It has an extensible spring and a fixing member that fixes the spring and is arranged around the spring ,
The fixing member breaks when the magnitude of the impact applied to the impact absorption unit is larger than a predetermined threshold;
A fixed part that does not allow the spring to stretch when the fixed member breaks, and an open part that allows the spring to stretch when the fixed member breaks are formed inside the fixed member. , shock absorption unit. A shock absorption unit for absorbing shock,
It has an extensible spring and a fixing member for fixing the spring,
The fixing member includes a first housing part for housing a part of the spring therein, a second housing part for housing a part of the spring therein, the first housing part and the first housing part. It has a maintenance part for maintaining the storage part of No. 2 so that it does not move relative to the storage part,
A shock absorbing unit, wherein the sustaining portion breaks when the magnitude of the shock applied to the shock absorbing unit is greater than a predetermined threshold. Inside the first accommodating part and the second accommodating part of the fixing member, there is a fixing part that does not allow the spring to stretch when the maintaining part breaks, and a fixing part that does not allow the spring to stretch when the maintaining part breaks. 3. The shock absorbing unit according to claim 2, wherein each of the shock absorbing units has an open portion that allows the spring to stretch. A shock absorption unit for absorbing shock,
an extensible spring; a fixing member for fixing the spring; a protective member disposed around the spring; and a seal disposed in contact with the protective member for liquid-tightly sealing the spring. It has a stop member,
A shock absorbing unit, wherein the fixing member breaks when the magnitude of the shock applied to the shock absorbing unit is larger than a predetermined threshold. The spring is a push spring,
The shock absorption unit according to any one of claims 1 to 4 , wherein the fixing member fixes the spring in a compressed state along the longitudinal direction. The shock absorption unit according to any one of claims 1 to 4 , wherein the spring is a tension spring. The fixing member is provided with a broken portion,
The shock absorption unit according to any one of claims 1 to 6 , wherein the fixing member breaks along the breakage portion when the magnitude of the impact applied to the shock absorption unit is larger than a predetermined threshold value. . The retaining portion of the fixing member includes a rod-shaped member disposed inside the spring,
The impact absorption unit according to claim 2 or 3 , wherein the rod-shaped member breaks when the magnitude of the impact applied to the impact absorption unit is larger than a predetermined threshold. The fixing member is arranged inside the spring,
A fixed part that does not allow the spring to stretch when the fixing member is broken, and an open part that allows the spring to stretch when the fixing member breaks are formed on the outside of the fixing member. The shock absorbing unit according to any one of claims 1 to 8 . A plurality of supports placed on a slope at predetermined intervals,
a falling object receiving member that is stretched over each of the pillars and catches falling objects that fall along the slope;
a wire body stretched between each of the pillars and the slope on the mountain side;
A shock absorption unit connected to the wire main body, the unit comprising: an extendable spring; a fixing member for fixing the spring; a protection member disposed around the spring; and a position in contact with the protection member. and a sealing member disposed in the spring for liquid-tightly sealing the spring, and the fixing member ruptures when the magnitude of the impact applied to the shock absorption unit is larger than a predetermined threshold. A shock absorption unit that
Rockfall prevention system equipped with 11. The shock absorbing unit according to claim 10 , wherein a plurality of types of shock absorbing units having different threshold values of the magnitude of the shock at which the fixing member breaks when a shock is applied to the shock absorbing unit are used so as to be arranged in series. Rockfall prevention system.

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