JP6038592B2 - Shock absorbing mechanism and falling object protection device having shock absorbing mechanism - Google Patents

Description

  The present invention relates to an impact absorbing mechanism for absorbing an impact and a fallen object protection apparatus incorporating the impact absorbing mechanism.

As an impact absorbing mechanism and a falling object protection device provided with the impact absorbing mechanism, for example, there is a falling rock protection fence 100 shown in the following patent document (see FIG. 11).
The rock fall protection fence 100 includes a plurality of support columns 101 that are erected at intervals in the slope width direction, and an upper side that is held by the plurality of support columns 101 and whose end is fixed to the anchor 102 on the side of the slope surface. A support rope 103 and a lower support rope 104, and a wire mesh 105 disposed on the sloped valley side and having an upper edge and a lower edge connected to each support rope are received by the wire mesh 105 to receive a fallen rock and nearby roads, etc. To prevent falling rocks.

  Further, according to the above-described prior art, the shock absorbing brake devices 103a and 104a are incorporated between the support ropes 103 and 104 and the anchor 102 (see FIGS. 11 and 12). The brake devices 103a and 104a are composed of a steel loop pipe 110 and tightening members 111 assembled in the vicinity of both ends of the loop pipe 110, and support ropes 103 and 104 are inserted from one end of the loop pipe 110. After a section of the rope is wound in a loop shape, a frictional force is generated between the rope and the inner surface of the loop pipe by tightly tightening both ends of the loop pipe together with the tightening member 111. In other words, the impact of the falling rock is mitigated by allowing the rope to be stretched while applying a certain brake to the support rope by the frictional force.

JP2009-024378

  By the way, since the brake device described above applies a brake by using a frictional force acting between the rope and the brake device, it takes time until the energy absorbing power is maximized. In other words, the braking device using friction is weak in initial braking and increases the amount of energy absorbed exponentially, so that it has not been able to sufficiently absorb the impact energy of falling rocks at the beginning of the collision with the highest energy amount.

  In addition, since the above-mentioned falling rock guard fence has insufficient braking force at the beginning of the collision, the rope subjected to the impact extends more than necessary. As a result, the protective nets that have fallen rocks overhang the sloped valley side. For this reason, when installing a rockfall protection fence, the rockfall protection fence had to be installed sufficiently away from the road to be protected. In other words, the installation location had to choose a slope with poor workability.

  In addition, since it is difficult to calculate the amount of energy absorbed at the beginning of a rock crash, in the design of a rock fall protection fence using this type of brake device, it is necessary to estimate a large amount of rope feed or underestimate the amount of energy absorbed. Inevitably, this increases the weight of the entire device and increases manufacturing costs.

  The present invention has been made in order to solve the above technical problems, and has an impact absorption mechanism that can efficiently and stably exhibit collision energy absorption capability, as well as excellent collision energy absorption capability, and can be used in manufacturing and construction. It is an object to provide a falling object protection device that is low in cost.

In order to solve the above technical problem, the present invention is an impact absorbing mechanism connected to an impact acting site,
A first rope and a second rope connected in parallel to the first rope;
The first rope has a surplus length with respect to the second rope, and the second rope is connected in a state in which the surplus length is secured.

  According to the shock absorbing mechanism of the present invention configured as described above, the first rope and the second rope connected in parallel to the first rope are provided. Further, since the first rope has an extra length with respect to the second rope, the collision energy acting on these ropes is first transmitted to the second rope and absorbed.

  That is, according to the present invention, the second rope is elastically deformed and plastically deformed prior to the first rope to absorb the collision energy. Further, since the collision energy is absorbed by the deformation of the rope itself without using the friction brake, there is no energy absorption loss, and a stable energy absorption capability can be exhibited immediately after the action of the collision energy.

  Further, when the second rope has a smaller longitudinal elastic modulus than that of the first rope and is compared with the same length, the second rope has an energy absorption longer than that of the first rope. It may be a type of rope.

  That is, according to this configuration, an energy absorption type rope having a small longitudinal elastic modulus and a large elongation in the vicinity of the breaking load is adopted as the second rope. Therefore, the energy absorption capability of the shock absorbing mechanism can be further enhanced.

Further, the surplus length of the first rope may be set to be larger than the extension length of the second rope.
In this configuration, since the second rope extends during the impact action, it is possible to draw out the absorption energy of the collision energy by the second rope to the maximum. Moreover, even if the amount of energy absorption is saturated and the second rope breaks, the connection state can be maintained with the first rope.

Moreover, you may set the surplus length of a said 1st rope less than the allowance of the said 2nd rope.
In this configuration, since the extra length is small with respect to the stretch margin, absorption of collision energy by the first rope is started before the second rope breaks. That is, the initial high collision energy is actively absorbed by the second rope, and then the impact is absorbed by both the first rope and the second rope when the impact is sufficiently weakened. Therefore, the breakage of the second rope due to the saturation of the energy absorption amount can be suppressed.

  Further, the extra length of the first rope may be configured such that the length of the first rope is 1.0 to 2.0 times the length of the second rope. Good.

  If the extra length of the first rope is set in this way, the collision energy can be sufficiently absorbed by the second rope, and the breakage can be suppressed. That is, a balanced shock absorbing mechanism can be designed.

  Moreover, the structure which ensured the extra length with respect to the said 2nd rope by bending the said 1st rope may be sufficient. According to this configuration, the surplus length can be secured by a simple operation such as bending the rope.

The first rope that is not the energy absorbing rope may be, for example, an existing rope provided in each part of the falling object protection device, in addition to the rope prepared for the shock absorbing mechanism.
Further, both the first rope and the second rope may be energy absorption type ropes.

In order to solve the above-described problems, the present invention
A protective net extending in the width direction of the slope, a cable body connected to the protective net to support the protective network, an anchor for fixing the cable body, and provided between the cable body and the anchor A fall object protection device comprising an impact absorbing mechanism,
The shock absorbing mechanism includes a first rope and a second rope connected in parallel to the first rope;
The first rope has a surplus length with respect to the second rope, and the second rope is connected in a state in which the surplus length is secured.

  According to the fallen object protection apparatus of this configuration, when a falling rock collides with the protection net, the impact is transmitted to the shock absorption mechanism through the rope body, and is caused by elastic deformation and plastic deformation of the second rope provided in the shock absorption mechanism. Immediately absorbed. Therefore, the projection of the protective net against the slope valley side can be minimized. Further, since the collision energy is absorbed by the deformation of the rope itself, there is no loss in energy absorption, and the calculation of the energy absorption amount becomes accurate and easy.

  Further, when the second rope has a smaller longitudinal elastic modulus than that of the first rope and is compared with the same length, the second rope has an energy absorption longer than that of the first rope. It may be a type of rope.

  In this configuration, an energy absorption type rope is employed as the second rope. Therefore, since the amount of collision energy absorbed by the second rope increases, the energy absorption capability of the falling object protection device can be further enhanced.

Further, the surplus length of the first rope may be set to be larger than the extension length of the second rope.
In this configuration, the energy absorption capacity of the second rope can be maximized, and even if the amount of energy absorption is saturated and the second rope breaks, the rope and the anchor are fixed by the first rope. The connection state with can be maintained.

  Moreover, you may set the surplus length of a said 1st rope less than the allowance of the said 2nd rope.

  In this configuration, since the energy absorption by the first rope is started before the second rope breaks, the breakage of the second rope due to the saturation of the energy absorption amount can be suppressed.

  Further, the extra length of the first rope may be configured such that the length of the first rope is 1.0 to 2.0 times the length of the second rope. Good.

  If the extra length of the first rope is set in this way, the collision energy can be sufficiently absorbed by the second rope and the breakage can be suppressed.

  Moreover, the structure which ensured the extra length with respect to the said 2nd rope by bending the said 1st rope may be sufficient. According to this configuration, the surplus length can be ensured by a simple operation such as bending the rope, so that it is possible to perform construction on the spot.

  The first rope that is not the energy absorbing rope may be a rope prepared for the shock absorbing mechanism or a rope for supporting the protective net. That is, the cable body for supporting the protective net and the first rope used for the shock absorbing mechanism may be combined.

  As described above, according to the present invention, it is possible to provide an impact absorption mechanism capable of efficiently and stably exhibiting the collision energy absorption capability, and a falling object protection device that is excellent in the collision energy absorption capability and is low in manufacturing and construction costs. it can.

The front view of the fallen object protection apparatus shown in this Embodiment. The top view of the fallen object protection apparatus shown to this Embodiment. The side view of the support | pillar shown to this Embodiment. The front view of the impact absorption mechanism shown in this Embodiment. The front view which shows the other specification of the impact-absorbing mechanism shown in this Embodiment. The front view which shows the other specification of the impact-absorbing mechanism shown in this Embodiment. The principal part enlarged view of the high tension | tensile_strength protection net | network shown to this Embodiment. The graph for comparing and evaluating the protection performance of the high-tension protection network shown in this embodiment. The figure which shows the test body (intersection strength test body) used in FIG. The side view which shows the other specification of the support | pillar shown in this Embodiment. The perspective view which shows the conventional rock fall protection fence. The perspective view of the brake device integrated in the conventional rockfall protection fence.

Hereinafter, the falling object protection apparatus 1 in which the shock absorbing mechanism 50 is summarized will be described together with the description of the shock absorbing mechanism 50 according to the present invention.
First, the fallen object protection apparatus 1 fixes a plurality of columns 10 standing in the width direction (left and right direction) of the slope along the lower edge (leg) of the slope, and attracts and fixes each column 10 to the slope mountain side. For supporting column 2, rope supporting rope 3 which is a connecting member arranged in the vertical direction with respect to column 10, upper horizontal rope 4 and lower side supported by each column 10 and extending in the slope width direction A rope 5 and a high-tension protective net 6 (face material), which is a high-tension wire net provided between the upper lateral rope 4 and the lower lateral rope 5, are provided.

  The column 10 has a body portion 11 (column body) made of a steel pipe having a diameter of 114.3 mm and a thickness of 4.5 mm, and a hinge for securing the column 10 to an anchor 20 provided on the ground at the lower end of the body portion 11. 17 is provided. Further, the support shaft 17a of the hinge is disposed so as to be orthogonal to the vertical direction of the slope, and is supported so as to be tiltable in the vertical direction with respect to the slope.

Further, the main body portion 11 of the support column 10 is provided with a bracket 12 for assembling the various ropes described above.
The brackets 12 are provided at two locations, the top and bottom of the column 10 and near the ground, and are welded so as to face the slope mountain side with the column 10 upright.
Further, U-shaped bolts 13 for connecting the column reinforcing ropes 3 are assembled to the tip portions of the brackets 12 and 12. The end portions of the column reinforcing rope 3 are connected to the brackets 12 and 12, respectively. The brackets 12 and 12 are connected to each other by the column reinforcing rope 3.

  The strut reinforcing rope 3 is a steel wire rope with 3 × 7φ18 and eye-finished at both ends. Further, the overall length of the bracket 12 is set so that a space of 150 mm or more is secured between the support reinforcing rope 3 and the support body part 11. Further, when the U-bolts 13 are tightened in a state in which the support reinforcement rope 3 is assembled to the bracket 12, tension is applied to the support reinforcement rope 3, and the support reinforcement rope 3 is firmly stretched between the brackets 12 and 12.

A through bolt 14 is assembled to the head of the column 10. The through bolt 14 penetrates the head of the column 10 from the lateral direction, and the column holding rope 2 inserted from the column head is locked to the head of the column 10 by the through bolt 14.
Here, an eye processing having a ring (loop) larger than the diameter of the support column 10 is applied to the end of the support column rope 2, and the end of the support column rope 2 through which the column head is inserted is By being hooked on the through bolt 14, the strut holding rope 2 is locked to the head of the strut 10 without sliding off from the head of the strut 10.

Then, the connection method of the upper horizontal rope 4 and the lower horizontal rope 5 is demonstrated.
The upper horizontal rope 4 and the lower horizontal rope 5 are steel wire ropes of 3 × 7φ18, and are supported on the slope mountain side of the support column 10 via brackets 12 and 12 provided in the vertical direction of the support column 10. Specifically, the horizontal ropes 4 and 5 are routed so as to pass the loop of the eye-processed portion (ring-shaped end portions 3b and 3c) of the column reinforcing rope 3 assembled to the bracket 12. That is, the horizontal ropes 4 and 5 are supported by the bracket 12 without being restricted in movement.

  Moreover, in the fallen object protection apparatus 1 shown in the present embodiment, an impact absorbing mechanism 50 is provided for each of the ropes 2, 4, 5 except the support reinforcing rope 3 to absorb energy at the time of falling rock collision. . The ropes 2, 4, and 5 are fixed to the anchors via the shock absorbing mechanism 50. 1 and 2 are turnbuckles for attracting and fixing the ropes 2, 4, and 5 to the anchor side, and the turnbuckle 2a is not essential but necessary. Provided accordingly.

The shock absorbing mechanism 50 includes a steel general-purpose wire rope (for example, a hard steel wire twisted rope defined in JIS G 3525) and an energy absorbing rope (manufactured by Tokyo Steel) that exhibits a high energy absorbing power near the breaking load. ).
Specifically, a conventional general-purpose steel rope 52 having a surplus length of about 1.3 to 1.5 times the energy absorption rope 51 (second rope) having an actual length of about 1 to 2 m is attached. Each end of the energy absorption rope 51 is caulked and bundled to the general steel rope 52 (first rope) side.

  In addition, as the specification, both ends of the energy absorption rope 51 are caulked and bundled with both ends of the general-purpose steel rope 52 to perform both ends (see FIG. 4), and one end is processed with eyes. The other end has a cut-off specification so that the winding grip 53 can be added at the site (see FIG. 5), and is selected as appropriate according to the terminal specifications of the ropes 2, 4 and 5 It is connected to each part rope 2,4,5. Further, in the present embodiment, a wire rope having a configuration of 3 × 7φ18 is adopted as the conventional general-purpose steel rope 52, and a wire rope having a configuration of 3 × 7φ18 is adopted as the energy absorption rope 51.

  Further, the characteristics of the energy absorption rope 51 will be described. The energy absorption rope 51 has a characteristic that the longitudinal elastic modulus is smaller than that of the general-purpose steel rope 52 and the elongation near the breaking load is large.

  This characteristic is obtained by a special composition ratio of the rope, for example, component ratio C: 0.001% to 0.15%, Si: 0.01% to 1.5%, Mn: 0.3% to 3%. 0.0%, P: 0.05% or less, S: 0.02% or less, Cr: 14.0% to 26.0%, Ni: 86.0% to 22.0%, N: 0.02% In the following, the rope can be obtained by austenite-forming heat treatment after drawing and twisting a steel strand consisting essentially of a soft stainless steel wire such as Fe.

Table 1 shows the relationship between the rope length per energy absorption rope and the energy absorption amount.
In addition, the rope specifications of the test piece are φ18 (3 × 7 SS / O), cross-sectional area A: 134 m ² , breaking load RBS: 80 kN, elastic elongation EL1: 5%, plastic elongation EL2: 15% (received collision energy) Elongation after EL1 <EL2), rope length L1: 1 to 20 m.

  Moreover, the calculation formula of energy absorption amount is derived by the following formula.

  According to the above formula, the larger the values of elastic elongation EL1 and plastic elongation EL2, the greater the amount of energy absorbed per rope. That is, it can be said that the rope material that is easy to stretch has a higher energy absorption rate.

Moreover, according to various tests, the elongation in the vicinity of the breaking load of the conventional general-purpose steel rope 52 applied to the horizontal ropes 4 and 5 and the strut retainer rope 2 remains at 3 to 5%, and the energy absorbing rope 51 on one side. The elongation in the vicinity of the breaking load is 50% or more. That is, when the energy absorbing rope 51 is pulled along with falling rocks to cause plastic deformation, collision energy several times as much as that of the conventional steel rope is absorbed.
In addition to the rope of the test specimen shown in Table 1 above, other specifications can be used as the energy absorption rope.

  Since the energy absorbing rope 51 absorbs a lot of energy in the plastic deformation region as described above, the rope easily breaks when the energy absorption amount is saturated. Therefore, in the present shock absorbing mechanism 50, a conventional general-purpose steel rope 52 is connected in parallel to the energy absorbing rope 51 with a surplus length, and even if the energy absorbing rope 51 is fully extended and broken, this conventional type The general-purpose steel rope 52 is used to connect the ropes 2, 4, 5 and the anchors together.

  As described above, the shock absorbing mechanism 50 shown in the present embodiment has a longitudinal elastic modulus smaller than that of the general-purpose steel rope 52 and the general-purpose steel rope 52 and has the same length. The energy absorption rope 51 is longer than the general-purpose steel rope 52. Further, the general-purpose steel rope 52 is bent to ensure a surplus length with respect to the energy absorption rope 51, and the energy absorption rope 51 and the general-purpose steel rope 52 are connected in parallel with the surplus length secured. .

  The shock absorbing mechanism 50 as described above allows, for example, the following deformation. That is, the energy absorbing rope 51 and the versatile steel rope 52 are formed separately from each other as shown in FIG. 6 without joining them to each other. And the turnbuckle 4a may be connected. In this way, it is only necessary to replace the rope deformed by the load caused by the collision of the falling object.

  The high tension wire mesh 6 that is a high tension protection net is supported on the slope mountain side by the ropes 2, 4 and 5 in which the shock absorbing mechanism 50 is incorporated in this way.

The high tension wire mesh 6 is obtained by using a high tension wire as a strand and processing the strand into a diamond shape. Further, in the knitting net processing, as shown in FIG. 7, the strands 6a and 6b are inscribed so as to draw an arc without bending at the portion 6d where the strands 6a and 6b intersect and cross each other. Yes.
Specifically, spiral processing is performed to draw an elliptical spiral on each strand, and the adjacent strands are knitted so that one strand is sequentially inserted between the pitches of the other strands. Similarly, another strand 6c is added in the width direction of the high tension wire mesh 6 to form a mesh.

  In the present embodiment, a high-strength wire having a diameter of 3.2 to 5.0 (preferably 4.0) and a cross-sectional strength of 1400 N / mm2 is used. Further, as the mesh, a 50 mm equilateral rhombus mesh or a vertically long rhombus mesh is adopted, and the amount of processing of each strand is adjusted so that the thickness is about 20 to 30 mm.

  In addition, the high-strength wire mesh 6 of this structure has higher shock absorbing performance than the conventional diamond wire mesh (galvanized wire mesh of galvanized iron wire defined in JIS G 3552) that is popular as a wire mesh for rockfall protection, It is difficult to break. This characteristic is obtained by the interaction between the above-described knitting net processing and the high tension wire used for the wire.

  First, when an impact due to falling rocks or the like is applied to the high-tensile wire mesh 6, each strand that draws an elliptical spiral is in the long side direction of the ellipse (in the direction of arrows A and B in FIG. 7) as viewed from the direction of travel of the spiral. Absorbs collision energy while elastically deforming. That is, at the initial stage of the collision, each of the strands wound spirally absorbs the collision energy while being elastically deformed in the width direction of the high tension wire mesh 6. Subsequently, when the deformation at the intersection of each strand reaches the plastic region, each strand is bent at the intersection, and the collision energy is absorbed by the plastic deformation at this intersection. Further, when each strand is pulled in the line direction between the intersections from this state, the strand is elastically deformed and plastically deformed in the line direction to absorb the collision energy.

  As described above, the high tension wire mesh 6 as the high tension protection mesh is not limited to deforming the wire in the direction of the wire, but is knitted so that each wire is bent at the intersection by an impact. Compared to the above, the absorbing power of collision energy is higher.

FIG. 8 is a load-elongation curve graph for comparing and evaluating the protective performance of the high-strength wire mesh 6 having the above specifications and the conventional diamond wire mesh.
In each graph, the vertical axis represents the test load (unit: N), and the horizontal axis represents the deformation (mm).
Moreover, the evaluation result of the high tension wire mesh 6 shown in the present embodiment is shown by a solid line in FIG. 8A, and the evaluation result of a conventional diamond wire mesh to be compared is shown by a solid line in FIG. 8B. In addition, an intersection strength specimen that reproduces the scale of each protective mesh was used as a specimen. In addition, the net | network specification reproduced with each test body was compared with the braided net | network of intersection angle 85 degrees (phi) 4. Moreover, the test body is shown in FIG. Each test body 60 is composed of a pair of upper and lower convex pieces 61, 61. The wire 62 is knitted between the convex pieces 61, 61 to reproduce the mesh. Further, three test bodies 60 are prepared for each wire mesh, and the load resistance is measured by applying a tensile load up and down by placing the test body on a testing machine.

  Moreover, the evaluation method can be grasped by comparing both graphs. In FIG. 8 (a), there is a case where the solid line is interrupted, but this is because the test body was detached from the testing machine during the test, and the test results of the high tension wire mesh 6 are the remaining two solid lines a and b. It was evaluated with.

Comparing FIG. 8A and FIG. 8B, the conventional rhombus wire mesh shown in FIG. 8B shows an elongation of about 13 mm in the vicinity of about 7000 N in each trial (solid line c). The high tension wire mesh (solid line a) shown in a) shows an elongation of about 30 mm around 16000N.
That is, it can be said that the high tension wire mesh 6 has a large load capacity and allowance for extension, and is about twice as high as the maximum allowable load compared to the conventional diamond wire mesh.

  Next, a method for assembling the protective net 6 that is the above-described high-tension wire net will be described. The high tension wire mesh 6 is assembled between the upper lateral rope 4 and the lower lateral rope 5 by using a coupling coil 16 (φ4 mm × 70 mm × 300 mm). Specifically, the high tension wire mesh 6 is covered from the slope mountain side from the upper horizontal rope 4 to the lower horizontal rope 5, and the upper coil and the lower edge of the high tension wire mesh 6 are folded back to assemble the coupling coil 16. Two coupling coils 16 are provided at the upper edge and the lower edge of the high tension wire mesh 6. Further, as shown in FIG. 1, when there is a break in the high-tensile wire mesh 6 between the support columns 10, 10, the coupling coil 16 is incorporated in the longitudinal direction of the high-tensile wire mesh 6 to connect the protective meshes.

  Further, in a state where the high tension wire mesh 6 is assembled to the horizontal ropes 4 and 5, a space 8 of about 150 mm is secured between the high tension wire mesh 6 and the column main body portion 11. In this space 8, each horizontal rope 4, 5 is suspended at a position away from the column 10 via the bracket 12, so that the slope of the column 10 can be obtained by assembling the high-tensile wire mesh 6 between the horizontal ropes 4, 5. Space 8 is naturally secured on the mountain side.

  Further, the support reinforcing rope 3 and the high tension wire mesh 6 arranged in the vertical direction of the support 10 are not fixed, and the horizontal ropes 4 and 5 also move the support 10 in the linear direction as described above. Since it is supported without being restrained, the high-tension wire mesh 6 can bend in the entire region without being restrained by the support 10. That is, the high tension wire mesh 6 is provided so as to be movable with respect to the column 10 and the column reinforcing rope 3.

  As described above, the fallen object protection apparatus 1 shown in the present embodiment includes a plurality of support columns 10 standing at intervals in the slope width direction, and the ropes 2, 3, 4, 5 connected to the support columns 10. And a high tension wire mesh 6 supported by the upper horizontal rope 4 and the lower horizontal rope 5 among these ropes (cord). The upper lateral rope 4, the lower lateral rope 5, and the strut retainer rope 2 are provided with an impact absorbing mechanism 50, and each of the ropes 4, 5, 2 is connected to the anchor via the impact absorbing mechanism 50.

  Further, since the shock absorbing mechanism 50 does not use the friction brake and absorbs the collision energy by entrusting the deformation of the energy absorbing rope 51 itself, when the collision energy acts on the energy absorbing rope 51 through the respective ropes 2, 4, 5. The collision energy is immediately absorbed without loss accompanying the elastic deformation and plastic deformation of the energy absorption rope 51. Therefore, since the protrusion of the protective net 6 that is a high-strength wire mesh against the sloped valley side is minimized, the fallen object protection apparatus 1 can be installed close to the road to be protected. That is, the falling object protection device 1 can be installed not only on a slope with a poor scaffold but also on a flat place with good workability.

  Moreover, since the amount of collision energy absorbed can be easily grasped by carrying out a load resistance test of the energy absorption rope 51 and estimating a collision speed of falling rocks on the construction surface, in the strength design of the falling object protection apparatus 1. A cost-effective design is possible.

The above-described embodiment is merely an example, and the details can be changed according to various specifications.
For example, in this embodiment, the support column 10 is installed by providing the hinge 17 at the lower part of the support column 10. However, the support column 10 can also be installed using, for example, a steel pipe pile 18 embedded in the ground. In this case, for example, about 1/6 is buried in the ground from the lower end of the support column 10 as shown in FIG. The length of the lower end of the supporting pillar 10 to be embedded is not limited to the above, but specifically, the steel pipe pile 18 as a foundation is inserted deep into the ground, and then the pillar 10 is inserted into the steel pipe pile 18. The lower end is inserted, and concrete 19 is poured into the gap to fix the column 10.

  In the present embodiment, in setting the extra length of the general-purpose steel rope 52, the length of the general-purpose steel rope 52 is 1.3 to 1.5 times the length of the energy absorption rope 51. Although the surplus length is set as described above, the surplus length of the general-purpose steel rope 52 may be set to be larger than the extension of the energy absorption rope 51. In this case, since the energy absorption rope 51 is fully extended, it is possible to draw out the absorption power of the collision energy in the energy absorption rope 51 to the maximum.

  Conversely, the extra length of the general-purpose steel rope 52 may be set to be smaller than the extension of the energy absorption rope 51. In this case, since the collision energy acts on the general-purpose steel rope 52 before the energy absorption rope 51 breaks, both the energy absorption rope 51 and the general-purpose steel rope 52 can absorb the collision energy in the later stage of the collision. This also suppresses breakage of the energy absorption rope 51 due to saturation of the energy absorption amount.

  When the above-described numerical value described in the present embodiment is adopted in setting the surplus length, the energy absorbing rope 51 can sufficiently exhibit the absorbing power of the collision energy and can also suppress the breakage. That is, a balanced shock absorbing mechanism 50 can be designed.

  In the present embodiment, one energy absorbing rope 51 is assembled to the general-purpose steel rope 52, but a plurality of ropes may be provided. Further, instead of the general-purpose steel rope 52, the respective ropes 2, 4, 5 provided in the falling object protection apparatus 1 may be directly used. That is, the existing rope and the general-purpose steel rope 52 used for the shock absorbing mechanism 50 may be used together. In this case, the existing ropes 2, 4, 5 may be bent at the site to secure the surplus length.

  In the present embodiment, the shock absorbing mechanism 50 is configured by combining the general-purpose steel rope 52 and the energy absorbing rope 51, but the energy absorbing ropes 51 may be combined. That is, both the ropes used for the collision absorbing mechanism 50 may be the energy absorbing rope 51.

  Moreover, in this Embodiment, although this fallen object protection apparatus 1 was provided along the lower edge (slope) of a slope, you may provide in the middle of a slope. Furthermore, although the plurality of columns 10 are provided in the slope width direction, one column may be used depending on the location. In addition, the specifications of the ropes 2, 3, 4, and 5 of the falling object protection device 1 and the specifications of the ropes 51 and 52 provided in the shock absorbing mechanism 50 can be changed. Further, the specification of the face material is not limited to the high-strength wire mesh that is a high-strength protective mesh, and a diamond-shaped wire mesh that is a conventional protective mesh may be used. As described above, the specifications of the falling object protection apparatus 1 shown in the present embodiment can be variously changed.

In the present embodiment, the shock absorbing mechanism 50 is assembled to the falling object protective device 1, but the use of the shock absorbing mechanism 50 is not limited to the falling object protective device 1, and can be used in various places as long as the shock acts. Can be assembled and used.

DESCRIPTION OF SYMBOLS 1 Falling object protective device 2 Prop back rope 2a Turnbuckle 3 Prop reinforcing rope 3b, 3c Eye processing part (ring-shaped end part) of prop reinforcing rope
4 Upper lateral rope 4a Turn buckle 5 Lower lateral rope 5a Turn buckle 6 High tension protective mesh (face material, high tensile wire mesh)
6a, 6b, 6c Elementary wire 6d Intersection point of element wire 8 Collision avoidance space 10 Column 11 Column body portion (column body)
12 Bracket (Face material support)
13 U-bolt 14 Through bolt 16 Coupling coil 17 Hinge 17a Support shaft 18 Steel pipe pile 19 Concrete 50 Shock absorption mechanism 51 Energy absorption rope 52 Conventional general-purpose steel rope 53 Winding grip 60 Test body 61 Convex piece 62 Wire DESCRIPTION OF SYMBOLS 100 Falling rock guard 101 Support column 102 Anchor 103 Upper support rope 103a Brake device 104 Lower support rope 104a Brake device 105 Wire net 110 Loop pipe 111 Tightening member

Claims (10)

An impact absorbing mechanism connected to the impact site,
A first rope and a second rope connected in parallel to the first rope;
The first rope has a surplus length with respect to the second rope, and the second rope is connected in a state in which the surplus length is secured ,
When the second rope has a smaller longitudinal elastic modulus than that of the first rope and is compared with the same length, the second rope has an energy absorption type that has a longer margin to break when compared with the first rope. A shock absorbing mechanism characterized by being a rope . 2. The shock absorbing mechanism according to claim 1, wherein an extra length of the first rope is set to be larger than an extension margin of the second rope. 2. The impact absorbing mechanism according to claim 1, wherein an extra length of the first rope is set to be smaller than an extension margin of the second rope. The extra length of the first rope is set such that the length of the first rope is 1.0 to 2.0 times the length of the second rope. The impact absorbing mechanism according to any one of claims 1 to 3 . The impact absorbing mechanism according to any one of claims 1 to 4 , wherein the first rope is bent to secure an extra length with respect to the second rope. A protective net stretched in the width direction of the slope, and a cable body connected to the protective net to support the protective net,
A falling object protection device comprising an anchor for fixing the rope and an impact absorbing mechanism provided between the rope and the anchor,
The shock absorbing mechanism includes a first rope and a second rope connected in parallel to the first rope;
The first rope has a surplus length with respect to the second rope, and the second rope is connected in a state in which the surplus length is secured ,
When the second rope has a smaller longitudinal elastic modulus than that of the first rope and is compared with the same length, the second rope has an energy absorption type that has a longer margin to break when compared with the first rope. Falling object protection device characterized by being a rope . 7. The fallen object protection apparatus according to claim 6 , wherein a surplus length of the first rope is set larger than an extension length of the second rope. The fallen object protection apparatus according to claim 6 , wherein an extra length of the first rope is set to be smaller than an extension length of the second rope. The extra length of the first rope is set such that the length of the first rope is 1.0 to 2.0 times the length of the second rope. The fallen object protection device according to any one of claims 6 to 8 . The falling object protection apparatus according to any one of claims 6 to 9 , wherein the first rope is bent to secure an extra length with respect to the second rope.

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