JP2021155978A - Protective net and impact-absorbing fence - Google Patents

Abstract

To provide a protective net and an impact-absorbing fence capable of exhibiting the original capturing performance of a synthetic fiber net while effectively suppressing the breakage of the synthetic fiber net when capturing falling objects.SOLUTION: A protective net comprises a fiber net 21 made of synthetic fiber, a net cover 25 superposed on the impact receiving surface of the fiber net 21, and a plurality of connectors 30 attaching the net cover 25 to the fiber net 21, wherein the net cover 25 can be separated from the fiber net 21 so that the net cover 25 can envelop the falling object during the impact.SELECTED DRAWING: Figure 1

Description

The present invention relates to a shock absorbing technique for catching falling objects such as rockfalls, landslides, and avalanches, and particularly to a synthetic fiber protective net and a shock absorbing fence having improved catching property of falling objects.

Patent Documents 1 and 2 disclose a protective net made of synthetic fibers in which net threads made of synthetic resin, chemical fibers and the like are knitted in a net shape.
Compared to metal nets such as wire ropes and wire mesh, synthetic fiber protective nets are softer and lighter in weight, so they are easier to carry and handle. It has the characteristic of
Patent Document 3 discloses a protective net made of synthetic fiber in which a fine net is superposed on the slope mountain side of the coarse net to improve the dispersion performance of impact force.
The coarse net has the main purpose of absorbing shock, and the fine net has the main purpose of preventing the passage of pebbles and the like, and the peripheral edges of each of these nets are attached to adjacent columns and stretched.

Japanese Unexamined Patent Publication No. 2003-261910 Japanese Unexamined Patent Publication No. 2005-3075772 Japanese Unexamined Patent Publication No. 2013-155493

The conventional protective net has the following problems.
<1> Generally, a protective net made of synthetic fiber is more flexible than a metal net, so that the protective net freely deforms following the uneven shape of the surface of a falling object such as a rock mass at the time of receiving a shot. As a result, cuts are likely to occur in the protective net.
Further, when the falling object collides with the protective net while rotating, rotational frictional heat is generated on the receiving surface of the protective net.
In this way, the conventional synthetic fiber protective net does not have a resistant structure that takes into account the rotation of falling objects such as rock masses, so the net material is easily torn when a falling object collides, and the original protective net has. The capture performance cannot be fully exhibited.
<2> The protective net of Patent Document 3, which is simply a superposition of two synthetic fiber nets having different mesh dimensions, does not have a structure considering the rotation of a falling object, so immediately after the fine net is torn in advance. The coarse net exposed to the surface is torn, and the original capture performance cannot be exhibited.
<3> In order to increase the cut strength of the protective net made of synthetic fiber, for example, a method of increasing the diameter of the net thread and a method of using a special fiber having excellent cut resistance as the net material can be considered.
The former method has a problem that the manufacturing cost of the protective net increases and the weight increases and the handling becomes poor, and the latter method has a problem that the manufacturing cost of the protective net increases and the flexibility of the net material is impaired and the impact energy is impaired. There is a problem that the absorption performance of the energy is reduced, and it is difficult to practically adopt either method.

The present invention has been made in view of the above points, and an object of the present invention is to make a synthetic fiber while effectively suppressing breakage of a synthetic fiber net even if a falling object collides while rotating. The purpose of the present invention is to provide a protective net and a shock absorbing fence that can exhibit the original catching performance of the net.

The present invention is a flexible protective net that catches falling objects by bending and deformation, and is a fiber net that is a net-like material made of synthetic fibers and a net cover that is superposed on the receiving surface of the fiber net. The net cover is configured to be separable from the fiber net so that the net cover wraps the falling object at the time of receiving the attack.
In another embodiment of the present invention, the net cover is a synthetic fiber net-like material or sheet-like material having both a rigidity larger than that of a fiber net and a flexibility smaller than that of a fiber net.
In another embodiment of the present invention, the elongation of the net cover is smaller than the elongation of the fiber net so that the tension of the net cover is superior to the tension of the fiber net at the time of receiving.
In another embodiment of the present invention, the mesh of the net cover has a dimensional relationship smaller than that of the fiber net so that a falling object does not directly hit the fiber net.
In another embodiment of the present invention, the fiber net is provided with a frame rope capable of elastic deformation, which is attached by inserting the protective net into a mesh on the periphery of the fiber net so that the protective net can be attached to a support member such as a support. The periphery of the fiber net can be held via the frame rope.
In another embodiment of the present invention, the breaking elongation of the frame rope is larger than the breaking elongation of the fiber net so that the frame rope and the fiber net cooperate to absorb the impact energy of the falling object at the time of receiving. It is set to.
The present invention is a shock absorbing fence in which a protective net is laid horizontally between columns erected at intervals, and is provided with any one of the above-mentioned protective nets, and the left and right sides of the fiber net constituting the protective net. Is supported by adjacent columns, and the net cover that constitutes the protective net is located on the mountain side of the slope. It was configured as follows.
In another embodiment of the present invention, in order to prevent the fence height of the protective net from being lowered, an upper side rope may be stretched between the upper parts of adjacent columns, and the upper side of the fiber net may be suspended on the upper side rope.

The present invention has at least one of the following effects.
<1> Even if a falling object collides while rotating, the original capture performance of the fiber net constituting the protective net can be exhibited while effectively suppressing the breakage of the fiber net made of synthetic fiber.
<2> Since the net cover separates and covers the surface of the falling object when the falling object is captured, the net cover protects the fiber net and does not directly transmit the rotation of the falling object to the fiber net.
Therefore, the breakage of the fiber net due to the rotation of the falling object can be effectively suppressed.
<3> Since the net cover does not deform too much according to the outer shape of the falling object, the load transmission area to the fiber net through the net cover is expanded.
Therefore, it is possible to prevent the load from being locally concentrated on the receiving surface of the fiber net when the falling object is captured.
<4> Since the structure is simply a combination of the net cover and the fixture on the fiber net, it is necessary to use a large-diameter net thread or a special fiber with excellent cut resistance as the net thread of the fiber net. There is no.
Therefore, there is no concern that the production cost of the fiber net will increase, the weight will increase, and the transportability and handleability will deteriorate.
<5> By making the mesh of the net cover smaller than the mesh of the fiber net, the protective performance of the fiber net by the net cover is improved.
<6> By making the breaking elongation of the frame rope larger than the breaking elongation of the fiber net, the frame rope and the fiber net can cooperate with each other to absorb the impact energy of the falling object at the time of receiving.
<7> By suspending the upper side of the fiber net on the upper rope stretched between the upper parts of the adjacent columns, it is possible to prevent the fence height from lowering at the center of the upper side of the protective net and increase the span length of the columns.

Perspective view of a shock absorbing fence equipped with a protective net seen from the mountain side of the slope Explanatory drawing of the protective net without the net cover and the mounting part on the upper part of the support Explanatory drawing of the net cover with a part omitted In the explanatory view of the fixture, (A) is a perspective view of the resin binding band, and (B) is a perspective view of the connecting coil. Model diagram of shock absorbing fence at the initial stage of capturing falling objects Model diagram of the shock absorbing fence with the net cover separated

The present invention will be described below with reference to the drawings.

<1> Impact Absorption Fence Explaining with reference to FIGS. 1 and 2, the impact absorption fence is a protective net vertically laid between a plurality of columns 10 erected at predetermined intervals and a plurality of columns 10. 20 and. The main materials constituting the shock absorbing fence will be described in detail below.

<2> Columns The columns 10 can be any kind of known steel materials such as shaped steel and steel pipes, concrete columns, filled steel pipes obtained by combining steel pipes and concrete, and the like.
A plurality of hooks to which the protective net 20 can be attached are provided on the outer peripheral surface of the support column 10.
The erection form of the stanchion 10 may be erected so as to be tiltable, or the lower portion of the stanchion 10 may be embedded in a concrete foundation, the local ground, or the like so as to be erected so as not to be tilted.
Further, if necessary, a retaining rope 11 is connected between the head of the support column 10 and the mountain side anchor.
A plurality of hooks 12 are provided on the upper and lower parts of the support column 10 so that the protective net 20 and the retaining rope 11 can be attached.

<3> Protective net The protective net 20 is a flexible net for catching falling objects such as rock masses, and is a square fiber net 21 and a net cover 25 which is polymerized and attached to the receiving surface of the fiber net 21. And a connector 30 that detachably attaches the net cover 25 to the fiber net 21.
The receiving surface of the fiber net 21 refers to the side surface of the slope of the net.

<3.1> Fiber net The fiber net 21 is a net-like material made of a flexible synthetic fiber, and has a mesh 22 having a size capable of catching a falling object. The fiber net 21 is a mesh 22 on the periphery of the fiber net 21. A frame rope 23 that is inserted into and integrally attached to the frame rope 23 is provided.
Both the fiber net 21 and the frame rope 23 are made of synthetic fibers and can be elastically deformed, and the impact energy can be absorbed by the elastic deformation of the fiber net 21 and the frame rope 23 at the time of receiving.

<3.1.1> Material of fiber net The fiber net 21 is a knotless net or a knitted fabric in which a plurality of synthetic fiber filaments such as polyethylene are twisted to form an extendable strand, and these are twisted in a lattice pattern. Nodular nets can be applied.
As the fiber net 21, a nature net (manufactured by Maeda Kosen Co., Ltd.) having a high impact dispersion force, in which weather-resistant polyester fibers are knitted as an extra-thick Raschel knit, can be used.

In the present invention, by adopting a combination of the net cover 25 and the fixture 30 as a means for increasing the cut strength of the fiber net 21, the net thread of the fiber net 21 can be made thicker and a special fiber having excellent cut resistance can be used. There is no need to use.
Therefore, there is no concern that the manufacturing cost of the fiber net 21 will increase, the weight will increase and the handleability will deteriorate, and the flexibility of the fiber net 21 will be impaired.

<3.1.2> Frame rope The frame rope 23 that supports the upper and lower sides and the left and right sides of the fiber net 21 may be in the form of an endless structure that is continuously arranged on the four sides of the fiber net 21, or the fiber net 21 may have an endless structure. It may be arranged in units of each side.
The frame rope 23 is a high-strength rope made of high-elongation fiber yarn and has high impact absorption performance.
Examples of the high elongation fiber yarn include synthetic fibers such as polyester, polyamide, vinyl chloride, and polypropylene.
The breaking elongation of the frame rope 23 is larger than the breaking elongation of the fiber net 21, and the frame rope 23 suppresses the free elastic deformation of the peripheral portion of the fiber net 21 at the time of receiving.

The frame rope 23 is not essential, and the frame rope 23 may be omitted when directly supporting the peripheral edge of the fiber net 21.

<3.2> Net cover The net cover 25 covers the receiving surface of the fiber net 21 and has a lightweight net shape having appropriate rigidity and flexibility capable of wrapping a falling object such as a rock mass at the time of receiving. It is a thing or a sheet.
The net cover 25 is preferably a net-like material or a perforated sheet-like material in order to avoid the influence of wind, but may be a non-perforated sheet-like material.
In addition to functioning as a protective member for the fiber net 21, the net cover 25 functions to alleviate the rotational transmission of falling objects toward the fiber net 21.

<3.2.1> Rigidity and flexibility of the net cover The net cover 25 has both appropriate rigidity and flexibility.
The rigidity of the net cover 25 is larger than that of the fiber net 21, and the flexibility of the net cover 25 is smaller than that of the fiber net 21.
The higher the rigidity of the net cover 25, the more easily the receiving portion of the net cover 25 is damaged when a falling object collides. It becomes easy to follow and deform according to the outer shape.
Therefore, it satisfies the flexibility that can prevent the net cover 25 from being damaged when the falling object collides, and the rigidity that the net cover 25 does not excessively follow and deform according to the outer shape of the falling object when the falling object is captured. As described above, the flexibility and rigidity of the net cover 21 are appropriately selected.

<3.2.2> Elongation of fiber net and net cover The elongation of the net cover 25 is smaller than the elongation of the fiber net 21.
This is because when the protective net 20 is deformed by receiving an impact, a tension difference is generated between the high elongation fiber net 21 and the low elongation net cover 25.
In other words, the tension of the net cover 25 is made to prevail to the tension of the fiber net 21 at the time of receiving, and the net cover 25 is separated.
Each elongation of the net cover 25 and the fiber net 21 is appropriately selected in consideration of the impact energy of a falling object and the like.

<3.2.3> Net cover dimensions The overall dimensions of the net cover 25 are not particularly limited.
Since the net cover 25 only needs to cover the receiving surface of the fiber net 21, it may be a single net cover 25 having substantially the same vertical and horizontal dimensions as shown in FIG. 1 or the net cover 25. May be a form in which the receiving surface of the fiber net 21 is divided into a plurality of parts and covered.

<3.2.4> Example of net cover The net cover 25 illustrated in FIG. 3 is a GM net (GM net) which is a composite polyester raschel net in which a monofilament 27 is inserted as a shape-retaining material in a weather-resistant polyester fiber raschel net 26. Maeda Kosen Co., Ltd.) can be used.
The net cover 25 has a higher strength than a normal fiber net, and has an appropriate rigidity so that the mesh (mesh shape) does not collapse.

<3.2.5> Net cover mesh When the net cover 25 is a net-like object having a mesh 28, if the mesh 28 of the net cover 25 has a larger dimensional relationship than the mesh 22 of the fiber net 21, the net cover There is it that loses the protective action of the fiber net 21 by 25.
Therefore, the mesh 28 of the net cover 25 has a smaller dimensional relationship than the mesh 22 of the fiber net 21.

<3.3> Connector The connector 30 is a fastener member for detachably attaching the net cover 25 to the fiber net 21.
The installation position of the plurality of connecting tools 30 is not limited to the peripheral portion of the net cover 25, and may be installed at an appropriate portion other than the peripheral portion.

<3.3.1> Example of connector FIG. 4 shows an example of the connector 30, and the connector 30 includes the resin binding band shown in FIG. 4 (A) and the connector 30 shown in FIG. 4 (B). A metal or resin connecting coil having a spiral shape can be applied.
When a resin binding band is applied as the connector 30, the breaking strength of the resin binding band is set so that the resin binding band breaks when a tension of a predetermined value or more is applied to the net cover 25. Make it lower than the breaking strength.
When the connecting coil is applied as the connecting tool 30, the connecting coil side is configured to break or unravel the spiral shape when a tension of a predetermined value or more is applied to the net cover 25.
Further, although not shown, it is also possible to apply a hook-and-loop fastener as the connector 30. When a hook-and-loop fastener is applied, the net cover 25 is configured to be separated when a tension of a predetermined value or more is applied to the net cover 25.
The connector 30 is not limited to the fastener member described above, and a commercially available simple fastener member capable of temporarily fixing the net cover 25 can be applied.

Further, when a tension of a predetermined value or more is applied to the net cover 25, the attachment portion on the net cover 25 side may be torn instead of the connector 30.

<4> Horizontal method of protective net The protective net 20 may be manufactured on-site by assembling the net cover 25 to the individually carried-in fiber net 21, or the completed protective net 20 may be delivered to the site. You may carry it in and use it.

In either method, the frame rope 23 of the fiber net 21 carried into the site is moored or connected to the hooks 12 at the upper and lower parts of the support column 10 to attach the four corners of the fiber net 21 to the support column 10 and between the adjacent columns 10. A protective net 20 is laid horizontally on the floor.
When the materials of the protective net 20 are individually carried in, the fiber net 21 is attached in advance between the columns 10, and then the net cover 25 is attached to the receiving surface of the fiber net 21 using the connector 30.

When the span of the support column 10 becomes long, the central portion of the upper side of the protective net 20 is lowered and the fence height is lowered.
At such a site, an upper rope 13 is stretched between the upper portions of adjacent columns 10, and the upper rope 13 and the upper side of the fiber net 21 cannot be separated via a connecting tool 14 such as a connecting coil or a shackle. By connecting to, the fence height is suppressed from becoming low.

The left and right side sides of the adjacent fiber nets 21 may not be connected and may be left in a free state, or may be separately sewn between the frame ropes 23 located on the left and right side sides of the adjacent fiber nets 21. A rope material may be hung to close the left and right side sides of the adjacent fiber nets 21.

[Capture action of falling objects by protective net]
Next, the action of capturing the falling object 40 by the protective net 20 will be described with reference to FIGS. 5 and 6.

<1> Deformation of the protective net at the initial stage of capture FIG. 5 shows a model diagram of a shock absorbing fence at the initial stage of capture of a falling object 40 such as a rock mass.
When the falling object 40 rotates along the slope 41 and collides with the protective net 20, the protective net 20 supported by the support column 10 bends and deforms toward the valley side of the slope centering on the receiving portion to absorb impact energy. While doing so, the falling object 40 is captured.

The falling object 40 collides with the net cover 25 of the protective net 20.
The net cover 25 protects the fiber net 21 from the cut of the falling object 40 while avoiding impact destruction by its own flexibility.
When the falling object 40 is captured, the net cover 25 is deformed to some extent, but due to its appropriate rigidity, it is not freely deformed according to the outer shape of the falling object 40.

<2> Separation of net cover Since the elongation of the net cover 25 is smaller than that of the fiber net 21, the tension of the net cover 25 increases with the deformation of the protective net 20.
When the protective net 20 is deformed, a difference in tension occurs between the fiber net 21 and the net cover 25, and this tension difference acts as a tensile force on the attachment portion (connector 30) of the net cover 25.
When the tension of the net cover 25 reaches a predetermined value or more, the net cover 25 is released from the attachment and the net cover 25 is separated from the fiber net 21.
When the falling object 40 collides while rotating, the net cover 25 is easily separated from the fiber net 21 under the influence of the rotation of the falling object 40.
FIG. 6 shows a model diagram of the shock absorbing fence when the net cover 25 is separated.

<3> Covering the falling object with the net cover The net cover 25 separated from the fiber net 21 is individually deformed without being affected by the fiber net 21 and wraps the surface of the falling object 40.
The falling object 40 abuts on the receiving surface of the fiber net 21 in a state of being wrapped in the separated net cover 25.

<4> Action of net cover When the rockfall 40 described above is captured, the net cover 25 constituting the protective net 20 exerts the following plurality of actions.

<4.1> Protective action of the fiber net Since the net cover 25 is interposed between the fiber net 21 and the falling object 40 even after being separated from the fiber net 21, the protective action of the fiber net 21 is continued as before the separation. To protect the fiber net 21 from incisions.

<4.2> Rotational insulation action of falling objects If the net cover 25 is attached to the fiber net 21 in an inseparable state, the rotation of the falling object 40 transmitted to the net cover 25 is transmitted to the fiber net 21. Also reported, the fiber net 21 is vulnerable to damage.

On the other hand, if the net cover 25 is configured to be separated from the fiber net 21 when the falling object 40 is captured, the net cover 25 becomes a covering member of the falling object 40, so that the rotation of the falling object 40 becomes the fiber net 21. Not directly transmitted.
Therefore, it is possible to effectively suppress the generation of frictional heat of the fiber net 21 due to the rotation of the falling object 40.
The rotation of the falling object 40 is absorbed by the net cover 25 sliding with respect to the fiber net 21, and the net cover 25 transmits only the impact force toward the slope valley side to the fiber net 21.

<4.3> Expansion action of load transmission area Since the net cover 25 does not freely deform according to the outer shape of the falling object 40 due to its appropriate rigidity, the net cover 25 alleviates the unevenness of the surface of the falling object 40. The contact surface with the fiber net 21 is rounded.
Since the contact surface of the net cover 25 with respect to the receiving surface of the fiber net 21 is not a point but a curved surface, the load transmission area to the fiber net 21 is expanded.
As a result of increasing the contact area with the fiber net 21 through the rigidity of the net cover 25 in this way, it is possible to avoid local load concentration on the receiving surface of the fiber net 21.

<5> Performance of Protective Net As described above, in the protective net 20 according to the present invention, cuts and frictional heat are unlikely to occur on the receiving surface of the fiber net 21 when a falling object 40 collides, so that the fiber net 21 is used. The original capture performance can be fully exhibited.

[Other Examples]
As shown in FIG. 1, in the previous embodiment, the form of the shock absorbing fence configured by vertically laying the protective net 20 between the columns 10 erected at intervals has been described, but the protective net 20 has been described. May be laid vertically between standing trees instead of the columns 10, or may be used in a horizontal form by supporting the periphery of the protective net 20 with a stationary member.

10 ... Support 11 ... Reservoir rope 12 ... Hook 13 ... Upper rope 20 ... Protective net 21 ... Fiber net 22 ... Fiber net mesh 23 ··················································································································································

Claims (8)

A flexible protective net that catches falling objects by bending and deforming.
A fiber net, which is a net-like material made of synthetic fibers,
A net cover that is polymerized and placed on the receiving surface of the fiber net,
The net cover consists of a plurality of connectors attached to the fiber net.
It is characterized in that the attachment portion of the net cover can be separated from the fiber net so that the net cover wraps the falling object at the time of receiving.
Protective net. The protective net according to claim 1, wherein the net cover is a net-like material or a sheet-like material made of synthetic fibers having both a rigidity larger than that of a fiber net and a flexibility smaller than that of a fiber net. .. The protective net according to claim 1 or 2, wherein the elongation of the net cover is smaller than the elongation of the fiber net. The protective net according to any one of claims 1 to 3, wherein the mesh of the net cover has a dimensional relationship smaller than that of the fiber net. The fiber net includes a frame rope capable of elastic deformation, which is inserted through and attached to a mesh on the periphery of the fiber net, and holds the peripheral edge of the fiber net via the frame rope. The protective net according to any one of 4. The protective net according to claim 5, wherein the breaking elongation of the frame rope is larger than the breaking elongation of the fiber net. It is a shock absorbing fence in which a protective net is laid horizontally between the columns erected at intervals.
The protective net according to any one of claims 1 to 6 is provided.
The left and right sides of the fiber net that makes up the protective net are supported by adjacent columns, and
The net cover that makes up the protective net is located on the mountain side of the slope.
It is characterized in that the attachment portion of the net cover is separated from the fiber net at the time of receiving a shot, and the separated net cover is configured to wrap the falling object and be captured by the fiber net.
Shock absorption fence. The shock absorbing fence according to claim 7, wherein an upper rope is stretched between the upper portions of adjacent columns, and the upper side of the fiber net is suspended from the upper rope.

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