JP2503501Y2 - Terminal fixing structure for rockfall prevention fence - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal fixing structure for a rockfall prevention fence.

[0002]

2. Description of the Related Art In many cases, it is installed under a steep slope such as a road or a railroad. In this case, as a means to protect against rockfall, columns are installed at predetermined intervals, and cables are installed between the columns. A rockfall prevention fence is commonly used that is installed in multiple stages and has a wire mesh stretched to absorb rockfall energy by elastic expansion of cables and compositional deformation of struts.
In this type of rockfall prevention fence, when fixing the cable end to the column, a wedge socket type cable end fitting has been conventionally used. However, when such a cable end fitting is used, the socket is passed through the cable, the tip of the cable is broken into strands, a wedge is inserted, the wedge is tapped into the tapered hole of the socket, and the adjustment rod is inserted from the other end of the socket. Is a series of operations in which the nuts are inserted and connected so that the tips press the wedges. At that time, considerable skill is required for fitting the wedge into the cable so that the twist of the cable does not return and for controlling the wedge. Therefore, the construction is troublesome, time and labor are required, and it is difficult to confirm whether the fixing is sufficient because the wedge fits in the socket, and the fixing effect tends to vary depending on the skill level. there were. Further, when the fixed portion is removed for re-installation due to defective fixing or the like, there is no choice but to cut the cable, which may make it impossible to secure the required cable length, and there is a problem that the material yield deteriorates. Then, when there is a rock fall, the cable is pressed in the direction perpendicular to the axis, but at that time, in the wedge socket type, a concentrated load is applied to the socket mouth portion, and the cable is likely to be sheared. For this reason, even if the load is smaller than the set breaking load of the cable, the cable is cut from the socket mouth portion, and there was concern about the effect of absorbing rockfall energy. The present invention was devised to solve the above-mentioned problems, and its purpose is to obtain a very reliable and stable terminal fixing state, and construction is easy without any skill, It is to provide a rockfall prevention fence terminal fixing structure that makes it easy to check the quality of fixing.

[0003]

[Means for Solving the Problems] In order to achieve the above object, the present invention is to install a terminal support and an intermediate support on a foundation of a foot of a slope, install a plurality of cables between the supports, and wire mesh behind the cable. In a fence that is stretched and receives rockfall, the outer circumference of the end portion of the cable is wrapped and fixed with a grip, and the ring portion of the wrapped grip is fastened to a holding fitting attached to a terminal support.

[0004]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an example of a rockfall protection fence to which the present invention is applied. Reference numeral 1 is a terminal pillar, and 2 is an intermediate pillar, which is built on a concrete foundation 3 at the boundary between the foot of the slope A and a road or a railroad. Reference numeral 4 denotes a cable made of a wire rope, which is arranged in a plurality of stages in the height direction. Each end of the cable is fixed to the terminal support column 1 by the terminal fixing mechanism 6, and the intermediate region is fixed to the intermediate support column 2 by U bolts. Is held. Reference numeral 5 denotes a wire mesh, which is stretched on the back side of the terminal support 2 and the intermediate support 3.

The terminal fixing mechanism 6 is shown in FIGS. 2 to 5, and comprises a winding grip 7 and a holding metal fitting 8. The cable 4 consists of a wire rope with plating of, for example, a 3 × 7 structure, and the winding grip 7 is wound around the cable end 40 over a length of 5 times the diameter or more. On the other hand, the terminal support 1 is made of H-shaped steel or the like, and the holding metal fitting 8 is a shackle type in this embodiment. That is, the rod portion 80 of the holding metal fitting 8 is inserted into the hole of the web provided according to the installation interval, and the rod portion 80 of the grip 7 is wrapped around the yoke-shaped retaining portion 81 fixed to the tip of the rod portion by welding or the like. 7a is inserted, the ring portion 7
A is hooked by a pin 82 that is inserted through the fastening portion 81. A thimble 83 is preferably attached to the ring portion 7a as shown in FIG. Then, the nut 9 is attached to the rod portion 80.
Is screwed, and the nut 9 is rotated to hold the holding metal fitting 8.
Moves in the axial direction, and the cable tension is set and adjusted. FIG. 6 shows another embodiment. In this embodiment, an eyebolt type is used, the rod portion 80 is provided with a hole 84, and the ring portion 7a is inserted into this hole.

As shown in FIG. 4, the wrapping grip 7 has a plurality of (for example, 5 to 7) steel element wires arranged on the same plane and twisted in a spiral shape to form two flat wires. Has gripping feet 7b, 7b ', and these gripping feet 7a, 7b
A U-turn portion 7a 'having a rigid twist structure is formed at the tip of 7b. A friction agent is appropriately applied to the inner surfaces of the gripping feet 7b and 7b '. The cable end 40 has its U-turn 7
The grip foot 7b is positioned so as to hang over the start end of a ', and one grip foot 7b is first wrapped around the outer circumference of the cable end thereof as shown in FIG. 4, and the other grip foot 7b' is wrapped around the grip foot 7b. Is wrapped around. As a result, a terminal portion having the ring portion 7a is formed as shown in FIG. In the embodiment of FIGS. 2 and 3, after the ring portion 7a is formed in this manner, it is fastened to the holding metal fitting 8. In the embodiment shown in FIG. 6, one of the gripping feet 7a or 7b is previously attached to the hole 8 of the rod portion 80.
After passing through 4, grip feet 7b, 7b 'as described above
Is wrapped around the cable end 40. A vertical wire 50 is passed through an end portion of the wire net 5, and is fixed to the terminal support column 1 by a U bolt 51. Further, a horizontal wire is passed through the wire net 5 and is fixed by a slit of a slit bolt attached to the intermediate support column 2.

[0007]

In the present invention, the rockfall protection fence is constructed as shown in FIG. 1, and when rockfall occurs from the slope, it is absorbed by elastic expansion of the cable 4 and plastic deformation of the columns and deformation of the wire net, A large load is applied to the terminal fixing portion due to the collision of rockfall. In the present invention, the holding metal fitting 8 is attached to the terminal support 1, and the grip 7 is wrapped around the holding metal fitting 8.
The cable 4 is attached to the end 40
The flat gripping feet 7b and 7b 'are wound around the gripping feet, and the gripping feet 7b and 7b' exert a strong tightening force (grip force) and friction from the radial direction, and the holding metal fitting 8 moves backward through the ring portion 7a. Since the gripping feet 7b and 7b 'are pulled, they are self-tightening. As the gripping force is increased, a strong and stable holding force is obtained. And
Since the ring portion 7a is entirely swingable in a vertical plane around the pin 82 of the holding metal fitting 8, when a rockfall collides, a phenomenon of concentrated load on the socket mouth like in the case of a wedge socket is generated. And the terminal fixing force equal to or higher than the standard load of the cable can be exhibited. According to the experiments conducted by the present inventors, when a cable diameter is 8 mm, a wrapping grip having five strands and a strand diameter of 2.48 mm is used, and the grip length (from the root of the ring portion to the end of the short side foot) is used. When the length was 486 mm, a holding force of 3700 kgf (1.05% of the standard load) was obtained. Also, the cable diameter is 12 mm.
In the case of using a winding grip with 6 strands and a strand diameter of 3.20 mm and the grip length is 915 mm,
A holding force of 11,500 kgf (about 1.04% of the standard load) was obtained. Furthermore, when the cable diameter is 18 mm, the number of strands is 6
When a winding grip with a wire diameter of 4.19 mm was used and the grip length was 1135 mm, a holding force of 17900 kgf (about 1.1% of the standard load) was obtained. This is a remarkably high holding force as compared with the conventional wedge socket method.

[0008]

[Advantage of the Invention] According to the present invention described above, a terminal strut and an intermediate strut are built on the foundation of the foot of the slope, a plurality of cables are erected between the strut, and a wire mesh is stretched behind the cable to drop rocks. In the fence body that receives the wire, the outer circumference of the end of the cable 4 is wrapped around and fixed with a grip 7.
Since the ring portion 7a of the winding grip 7 is fastened to the holding metal fitting 8 attached to the terminal support 1, the following excellent effects can be obtained. It can be easily installed without requiring skill. In the present invention, the two twisted flat gripping feet 7b, 7b 'of the winding grip 7 are wound around the cable end portion 40, and the ring portion 7a formed thereby is fastened to the holding metal fitting 8. It is extremely simple because it is enough, requires no skill, and requires no special tools. Terminal fixing is strong and stable, and it is possible to judge from the outside whether the holding power is good or bad. In the present invention, the two flat gripping feet 7b, 7b 'of the spiral shape wind the cable in a wide area from the outer circumference, and the tightening force is further increased by pulling to the ring portion 7a, so that it is integrated with the cable. And a holding force equal to or higher than the cutting load of the cable is realized. Further, since it is sufficient to simply wind the cable around the outer circumference of the cable, there is no influence by the skill level of the operator, and a predetermined holding force can always be realized without variation. Further, since the fixing portion is entirely exposed and the holding force can be determined only by checking whether or not the gripping feet 7b, 7b 'are wound without a gap, it is easy to inspect at the time of completion of construction and subsequent inspections. Reconstruction can also be easily done without cutting the cable. When releasing the fixing, the two flat gripping feet 7b,
It is sufficient to remove 7b 'from the cable 4 and it is not necessary to cut it like a wedge-type socket, so the cable length cannot be shortened. It can be constructed at low cost. Since the present invention includes only the winding grip 7, the holding metal fittings and the nut, the number of parts is small, and the work can be carried out at a low cost in combination with the simple work as described above.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a terminal fixing structure for a rockfall prevention fence according to the present invention.

FIG. 2 is a side view of a terminal fixing structure for a rockfall prevention fence according to the present invention.

3 is a cross-sectional view of FIG.

FIG. 4 is a side view showing the connection between the cable end portion and the winding grip.

FIG. 5 is a side view illustrating a terminal fixing completion state.

FIG. 6 is a side view showing another embodiment of the terminal fixing structure of the rockfall prevention fence of the present invention.

[Explanation of symbols]

 1 Terminal Support 2 Intermediate Support 4 Cable 7 Winding Grip 7a Ring 7b, 7b 'Grip Feet 8 Holding Metal

Claims (3)

(57) [Scope of utility model registration request] 1. A fence in which a terminal support and an intermediate support are built on a foundation at the foot of a slope, a plurality of cables are erected between the supports, and a wire mesh is stretched behind the cable to receive falling rocks. The end fixing structure of the rockfall prevention fence, characterized in that the outer circumference of the end is gripped and fixed with a grip, and the ring part of this grip is fixed to a holding metal fitting attached to the terminal support. 2. The holding metal fitting has a rod portion and a yoke portion fixed to the tip of the rod, and the ring portion of the winding grip is inserted into the yoke portion and fixed by inserting a pin into the yoke portion. The terminal fixing structure for a rockfall prevention fence according to claim 1, which includes a structure. 3. The structure for fixing a terminal of a rockfall prevention fence according to claim 1, wherein the holding metal fitting has a rod portion with a hole, and the ring portion of the winding grip is inserted.