JP6573301B1 - Tension control device and guard fence - Google Patents

Abstract

To provide a tension control device and a protective fence that can control a damping performance according to the magnitude of a tensile force acting on a stay rope and can reduce a required cross-sectional performance of a column. A stay rope 40 arranged between an upper portion of a support column 10 and an upper side of a protective net 20 and a tension control device 30 of the stay rope 40 are used. The tension control device 30 includes a peripheral wall 32 provided on the upper portion of the support column 10 and a driven restraining mechanism 50 disposed inside the peripheral wall 32. The tensile force generated in the stay rope 40 at the time of receiving is attenuated by the tension control device 30 and the tensile force is transmitted to the outside of the tension control device 30 through the stay rope 40 from the receiving span to the adjacent span. Both ends of the extended stay rope 40 are connected to the upper side of the protective net 20 located on both sides of each column 10. [Selection] Figure 3

Description

  The present invention relates to an impact absorbing technique for catching falling rocks, landslides, avalanches, and the like, and more particularly, to a tension control device and a protective fence that can attenuate the impact force gradually from a receiving span through a support and reduce the load on the support.

The protective fence constructed by attaching a protective net between a plurality of support columns standing at a predetermined interval includes a type in which a protection net of a span unit is attached to adjacent support columns (Patent Document 1), and a plurality of spans. It is roughly classified into a type (Patent Documents 2 and 3) in which both ends of a protective net having a horizontal length that can be horizontally mounted are attached to a terminal column.
The former protective fence has a structure in which the impact load acting on the protective net is transmitted to the struts located on both sides of the receiving span. It has a structure to transmit to.
It is also known that a shock absorber is inserted into a part of a horizontal rope element constituting the protective net to improve the shock absorbing performance of the protective fence (Patent Documents 3 and 4).
In addition, a plurality of cable-stayed ropes are slidably moored at the upper and lower parts of each column, and the ends of each cable-stayed rope are connected to the upper and lower half of the protective net to change the height of the protective net There is also a protective fence that suppresses the above (Patent Document 5).

As a shock absorber attached to the protective fence, a friction sliding shock absorber (Patent Document 6) that attenuates using the peripheral frictional resistance of the rope element is widely known.
This type of shock absorber damps the tensile force of the rope element using the peripheral frictional resistance generated by tightening a part of the outer peripheral surface of the rope element with a plurality of tightening bolts. It is greatly affected by the tightening force of the rope element.
In general, the shock absorbing performance of the shock absorber is indicated by a tensile force when the rope element starts to slide.

JP 2007-32032 A JP 2017-95893 A JP 2009-24378 A JP 2009-144472 A Japanese Patent No. 5793633 JP-A-2005-282105

The conventional protective fence has the following problems.
<1> The protective fence represented by Patent Document 1 has a structure in which most of the impact load is transmitted to the columns on both sides of the receiving span.
Therefore, all struts must be made with high strength so that any span can be received, and the entire protective fence is forced to be uneconomical.
<2> Since the guard fence represented by Patent Documents 2 and 3 has a structure in which the impact load is finally supported by the terminal column, the terminal column must be manufactured with higher strength than the intermediate column.
In addition, the installation cost of the protective fence is further increased by additionally installing a side holding rope and a large anchor to prevent the terminal column from tilting.
<3> In the protective fence in which a shock absorber is inserted near both ends of the horizontal rope element as in Patent Document 3, the shock absorbing performance as the entire protective fence is low, and it is difficult to apply to a large-scale protective fence.
<4> With a protective fence inserted with a shock absorber in span units as in Patent Document 4, the load on the horizontal rope element in the receiving span can be reduced, but it is transmitted to the struts and horizontal rope elements outside the receiving span. Load is extremely small, and the load distribution performance of the entire protective fence is low.
<5> In the guard fence described in Patent Document 5 in which the cable-stayed rope is slidably moored on the upper and lower parts of the support, the pulling force of the slanted rope located in the receiving span causes the slanted rope and the support in the adjacent span. Propagate to the terminal post via. The impact force acting on the protective net also propagates to the terminal strut via the protective net in the adjacent span.
As described above, the protective fence of Patent Document 5 has the same problem as the above <2> because each tensile force generated on the cable-stretched rope and the protective net is concentrated on the terminal column.

The conventional friction sliding type shock absorber has the following problems.
<1> The conventional shock absorber cannot change the shock absorbing performance according to the magnitude of the tensile force acting on the rope element with a single shock absorber.
Therefore, the shock absorber must be individually manufactured according to the size of the shock absorbing performance.
<2> A conventional shock absorber cannot be expected to have a shock absorbing effect as a shock absorber unless it is tightened to near the limit at which the element wire of the rope element breaks. If the tightening force is insufficient, the desired shock absorbing performance cannot be obtained.
<3> In the conventional shock absorber, the tensile force shows the maximum value when the rope element starts to slide, and immediately after that, the tensile force decreases, and the tensile force decreases while going up and down for a while.
Therefore, although the effect of reducing the tensile force can be expected according to the sliding amount of the rope element, the strength of the rope element in the slid range is reduced due to severe damage to many strands.
<4> In the conventional shock absorber, the sliding tension decreases according to the sliding distance of the rope element, but particularly when the sliding distance of the rope element is large, the sliding tension decreases extremely.
<5> A plurality of tightening bolts are screwed onto the shock absorber having the rope element inserted therein, but the bolts must be tightened with a uniform tightening force so that the frictional resistance between the plurality of shock absorbers and the rope element is uniform. The buffering performance of each buffer device is greatly varied.
Therefore, it is necessary to manage the torque of the tightening bolts, but the torque management of many tightening bolts is troublesome.
<6> The total length of the rope element laid between the columns becomes longer by the extra length portion that allows for the sliding length of the rope element. Therefore, the material cost of the rope element increases, and the extra length of the rope element protrudes from both ends of the protective fence and hangs down, resulting in poor scenery.

The present invention has been made in view of the above points, and an object thereof is to provide at least one of the following tension control devices and protective fences.
<1> The damping performance can be controlled according to the magnitude of the tensile force acting on the rope element.
<2> The tensile force can be gradually attenuated in a process in which the tensile force is transmitted in a chained manner through adjacent struts through the rope element without concentrating the tensile force only on the receiving span.
<3> The required cross-sectional performance of the column can be reduced, and the cost of the protective fence can be reduced.

The present invention is a tension control device that is attached to the upper part of a support pillar constituting the protective fence and slidably anchors a rope element spanned between at least the upper part of the support fence and the upper side of the protective net located on both sides of the support pillar. The tension control device comprises a fixed peripheral wall having a braking surface curved on the inner surface, and a driven restraining mechanism disposed on the inner side of the peripheral wall. The driven restraining mechanism has a lower end portion. A pair of swing links pivotably supported and arranged in a V-shape, a central rope supported on the lower end pivot support portion of the pair of swing links, and supported on the upper end portion of each swing link And a rocking rope.
In the tension control device, the central rope is positioned between the pair of rocking ropes and lower than the rocking rope, and is arranged in an M shape between the plurality of rocking ropes and the central rope. A part of the rope element is sandwiched and restrained between the rocking surface of the rocking rope and the braking surface of the peripheral wall, and the pair of rocking links rocks around the lower end pivot part, thereby generating the rope element. The restraining force of the rope element can be controlled between the rocking rope and the braking surface of the peripheral wall according to the magnitude of the tensile force.
In another embodiment of the present invention, the braking surface of the peripheral wall is gradually reduced so that a facing distance between the rocking rope and the braking surface of the peripheral wall gradually decreases as the pair of swing links swing along the opening angle direction. Is curved.
In another embodiment of the present invention, the driven restraint mechanism is such that the braking surface of the peripheral wall is an arc surface, and the center of the lower end pivotal support portion of the pair of swing links is located below the center of the braking surface of the peripheral wall. The total length of each of the pair of swing links constituting the sway is related to the radius of the peripheral wall.
In another embodiment of the present invention, the radius of curvature of the braking surface of the peripheral wall gradually decreases along the opening angle direction of the pair of swing links.
In another embodiment of the present invention, the lower end pivot portions of the pair of swing links can be moved up and down, and the pair of swing links swing around the lower end pivot portion in conjunction with the vertical movement of the central rope.
In another embodiment of the present invention, the driven restraint mechanism includes guide means for restricting the movement direction of the central rope only in the vertical direction.
In another embodiment of the present invention, the driven restraining mechanism includes a stopper for restricting the uppermost position of the lower end pivotal support portion of the pair of swing links.
In another embodiment of the present invention, the driven restraining mechanism includes a spring that constantly biases the lower end pivotal support portions of the pair of swing links downward.
In another embodiment of the present invention, the driven restraint mechanism includes a bolt capable of adjusting the height position of the lower end pivotal support portion of the pair of swing links.
In another embodiment of the present invention, the lower end pivot portions of the pair of swing links may be pivotally supported at a fixed position so as not to move up and down.
Furthermore, the present invention provides a plurality of support columns that are erected on the foot of the mountain at a predetermined interval, a protective net that is laid horizontally between these support columns, a tension control device that is installed above each support column, and each tension control device. A protective fence including a rope element arranged between the upper sides of the protective nets located on both sides of each column, and any one of the tension control devices is used.
Both ends of the rope element extended to the outside of the tension control device are connected in span units to the upper side of the protective net located on both sides of each column, and the tensile force generated in the rope element at the time of impact is attenuated by the tension control device On the other hand, the tensile force is transmitted while being attenuated in a chain manner from the receiving span to the adjacent span through the rope element.
In another embodiment of the present invention, the end of the rope element arranged on the upper side of the protective net is capable of transmitting the tensile force generated in the rope element at the time of impact to the side anchor provided on the side of the terminal column. You may connect to a side anchor.
In another embodiment of the present invention, a tension force control device is installed at an upper portion of each support column higher than the upper side of the protection net, and both ends of the rope element moored to the tension control device are positioned on both sides of each support column. The upper side of the net may be connected obliquely.
In another embodiment of the present invention, the rope element moored to the tension control device may be horizontally mounted.

The present invention has at least one of the following effects.
<1> The tension control device can increase the restraining force of the rope element according to the magnitude of the generated tensile force of the rope element.
Therefore, the damping performance can be controlled according to the magnitude of the tensile force acting on the rope element without remodeling the tension control device or replacing some constituent members.
<2> Since the tension control device provided on the struts on both sides of the receiving span effectively attenuates the tensile force generated on the rope element of the receiving span, the load on the strut located in the receiving span is greatly reduced. it can.
In particular, since the tension control device exhibits a damping function from the time when a small tension difference is generated in the rope element, the impact load transmitted to the support can be remarkably reduced.
<3> The tensile force generated in the rope element of the receiving span is transmitted in a chained manner to the adjacent span via the support column without concentrating only on the receiving span, and a plurality of tension controls located in this transmission process The tensile force generated on the rope element by the device can be gradually attenuated.
<4> By providing a tension control device on each strut, it is possible to significantly reduce the load burden of each strut (intermediate strut, terminal strut) at the time of impact, and to reduce the required cross-sectional performance of the strut.
When the side anchor is provided, the required anchor strength of the side anchor can be reduced.
Therefore, the cost of the protective fence can be greatly reduced.
<5> When the rope element is slid, the oscillating rope rotates, so that no sliding occurs between the circumferential surfaces of the oscillating rope and the rope element.
Therefore, even if the rope element is crushed as the cross-sectional shape of the rope element is greatly changed, the rope element strands are not easily broken, and the rope element does not become slidable.
<6> The restraint restraint mechanism of the tension control device restricts the uppermost position of the lower pivot part of the pair of swing links with a stopper, thereby preventing excessive tightening of the rope element and reducing damage to the rope element during sliding. it can.
<7> The driven restraint mechanism of the tension control device includes a spring that biases the lower end pivot portions of the pair of swing links directly below, and a bolt that can adjust the height position of the lower end pivot portions of the pair of swing links. Thus, the sliding start tension and the maximum sliding force of the rope element can be adjusted without modifying the tension control device or exchanging some constituent members.

The front view which looked at the protection fence which concerns on this invention from the mountain side Illustration of an example of a protective net Explanatory drawing of the tension control device according to the first embodiment. Sectional view of IV-IV in FIG. It is an operation explanatory view of the tension control device, (A) is an operation model explanatory view before the impact, (B) is an operation model explanatory view at the time of the impact Explanatory drawing of the tension | tensile_strength control apparatus which concerns on Example 3. FIG. Explanatory drawing of the tension control apparatus which concerns on Example 4. FIG. Explanatory drawing of the tension control apparatus which concerns on Example 6. FIG.

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

<1> Outline of Guard Fence Describing with reference to FIG. 1, the guard fence is a guard fence that can be applied to falling rocks, landslides, and the like, and a plurality of support columns 10 erected on a slope or mountain skirt at a predetermined interval. (Terminal struts 10A, intermediate struts 10B), protective nets 20 laid across these struts 10, and tension control devices 30 installed on the upper portions of the respective struts 10 and on the extending portions 11 higher than the upper sides of the protective nets 20; The stay rope 40 is a rope element arranged between each tension control device 30 and the upper side of the protection net 20 located on both sides of each support column 10.

<2> Struts In this example, an embodiment will be described in which an extending portion 11 higher than the effective height of the protective net 20 is formed on the top of each strut 10A, 10B, and a tension control device 30 is provided on the extending portion 11.
The total length of the extending portion 11 is appropriately selected according to the span of the support column 10.

As each support | pillar 10, well-known support | pillars, such as a steel pipe, a concrete filling steel pipe, a concrete pillar, H steel, are applicable, for example.
The standing means for each column 10 may be any of a built-in type on a natural ground, a buried type in foundation concrete, and a non-built-up type that contacts the ground via a bearing plate provided at the lower end of the column.
Furthermore, the support column 10 may be configured to be tiltable via a hinge mechanism or the like.
Moreover, you may stretch | stretch a support | pillar holding rope between the upper part of each support | pillar 10, and a mountain side anchor.

<3> Protective Net The protective net 20 is a net-like object that is laid across three or more struts 10.
As the protective net 20, for example, a net described in JP-A-2015-20086 can be used.
Referring to FIG. 2, the protective net 20 includes a plurality of continuous ring elements 22 formed of a rope material 21, a plurality of closing cushions 23 for forming the plurality of continuous ring elements 22, And a plurality of connecting shock absorbers 24 for connecting the adjacent continuous ring elements 22 to each other.
The shock absorbers 23 and 24 may be of a frictional sliding type capable of gripping the two rope members 21, and each shock absorber 23 and 24 allows the rope member 21 to slide at the time of receiving. The tensile force of the rope material 21 is attenuated by expanding and contracting the ring.

  The protective net 20 is not limited to the illustrated form. For example, a rope net in which a plurality of rope members are arranged in a vertical and horizontal direction and an oblique direction (including a net in which a shock absorber is attached to an intersection of the rope members), and a plurality of single rings. One kind of ring net, rhombus wire net, high-strength wire net, fiber net, fiber net, etc., or a combination of these, which are inscribed and linked, can be used.

  Further, in this example, a mode in which the protection net 20 is provided in units of spans will be described, but the protection net 20 may have a total length over a plurality of spans.

<4> Tension Control Device The tension control device 30 illustrated in FIGS.
The tension control device 30 includes a substrate 31, a fixed peripheral wall 32 that is curved inward toward the periphery of the substrate 31, and a driven restraint mechanism 50 that is movably disposed inside the peripheral wall 32. The chain is transmitted in a chained manner from the receiving span to the adjacent span while controlling the tensile force generated in the stay rope 40 arranged in the cable.
Although FIG. 4 shows a form in which a lid member 35 having the same shape as the substrate 31 is disposed so as to face the substrate 31, the lid member 35 may be omitted.

<4.1> Substrate The substrate 31 is a flat plate for supporting the peripheral wall 32.
In the vicinity of the center of the substrate 31 and the lid member 35, a guide hole 34 that is a guide means for restricting the moving direction of the central rope 51 only in the vertical direction is formed vertically.
A substrate 31 is attached to the extending portion 11 of each support column 10 (terminal support column 10A and intermediate support column 10B) via mounting bolts or the like.

<4.2> Peripheral Wall The peripheral wall 32 is provided upright on the periphery of the substrate 31 and forms a curved braking surface 32a on the inside thereof.
The braking surface 32 a of the peripheral wall 32 may be formed at least in the upper half of the substrate 31.
In this example, a description will be given of a form in which the braking surface 32a is formed in an arc (curved surface having a constant radius of curvature). However, the braking surface 32a is not limited to an arc, and in short, the opening angle direction of the pair of swing links 55a and 55b. It is only necessary that the radius of curvature of the braking surface 32a be curved along the curve.

  The left and right sides of the peripheral wall 32 have openings 33 so that the stay rope 40 can be routed through the openings 33 to the driven restraint mechanism 50 inside the tension control device 30.

<5> Stay rope driven restraint mechanism The follow restraint mechanism 50 is a link mechanism for slidably restraining the stay rope 40 using a tensile force acting on the stay rope 40.

The driven restraint mechanism 50 illustrated in this example will be described. The follower restraint mechanism 50 is disposed in a V shape and has a pair of left and right swing links 55a and 55b pivotably supported at the lower end portion, and each swing link. The central rope 51 is pivotally supported on the lower end pivot portions of 55a and 55b, and the swing ropes 53a and 53b are pivotally supported on the upper ends of the swing links 55a and 55b.
An idling sheave can be applied to the plurality of ropes 51, 53a, 53b.
The central rope 51 is positioned between the left and right rocking ropes 53a and 53b and lower than the rocking ropes 53a and 53b.

<5.1> Oscillating links The pair of oscillating links 55a and 55b are link members of the same length for transmitting the push-up force of the central rope 51 to the oscillating ropes 53a and 53b. The support shaft 52 is pivotally supported.
The end of the support shaft 52 is engaged with the guide hole 34, and the swing links 55 a and 55 b swing in the left-right direction around the support shaft 52 in conjunction with the vertical movement of the support shaft 52.

<5.2> Central rope 51 A central rope 51 is pivotally supported on the support shaft 52 at the lower end of the swing links 55a and 55b.
In this example, a mode will be described in which the central rope 51 restricts movement in the left-right direction and allows only movement in the up-down direction.

<5.3> Oscillating Rings Oscillating ropes 53a and 53b are pivotally supported through the support shafts 54 at the upper ends of the respective oscillating links 55a and 55b. The swing ropes 53a and 53b can be slidably constrained by sandwiching the stay rope 40 with the braking surface 32a of the peripheral wall 32.
When the tensile force of the stay rope 40 is increased, the pair of swing links 55a and 55b are configured to swing toward the opening angle direction.

<5.4> Relationship between Circumferential Groove of Rope and Rope Diameter The depth of the circumferential grooves of the swinging ropes 53a and 53b is smaller than the rope diameter of the stay rope 40.
This is because when the stay rope 40 wound around the circumferential grooves of the rocking ropes 53a and 53b is pressed against the braking surface 32a of the circumferential wall 32, the outer peripheral surfaces of the rocking ropes 53a and 53b do not hit the braking surface 32a. It is for doing so.

<5.5> Dimensional relationship between the swinging radius of the swinging link and the radius of the braking surface Referring to FIG. 3, the dimensional relationship between the swinging radius of the swinging links 55a and 55b and the radius of the braking surface 32a of the peripheral wall 32 is shown. explain.
Swing link 55a, the center of the lower end pivot portion of 55b, i.e. such that the center _{P 1} of the central Sakuwa 51 is located below the center _{P 2} of the braking surface 32a, the swing link 55a, the total length of 55b and arcuate Is related to the radius of the braking surface 32a.
In other words, the distance from the center _{P 1} of the swing link 55a, 55b of the lower end pivotally supporting a is central Sakuwa 51 to swing Sakuwa 53a (53b) (swing links 55a, 55b swing radius) is braked distance from the center _{P 2} of the surface 32a to the braking surface 32a has a larger dimensional relationship (a radius of the braking surface 32a).
This is because the tension controller 30 controls the tension of the stay rope 40 moored to the driven restraint mechanism 50.
The effect of controlling the tensile force of the stay rope 40 by the tension control device 30 can be adjusted by appropriately selecting the difference in the vertical direction between the centers P ₁ and P ₂ .

Therefore, when the swing links 55a and 55b swing in the opening angle direction, the stay rope 40 located between the peripheral surfaces of the braking surface 32a and the swing ropes 53a and 53b according to the opening angle. The binding force (clamping force) increases.
The restraining force of the stay rope 40 changes in accordance with the magnitude of the generated tension of the stay rope 40 moored to the driven restraining mechanism 50, and increases in proportion to the opening angle (swing distance) of the swing links 55a and 55b. To do.

<6> Stay rope The stay rope 40 as a rope element is a rope material for transmitting a load over the entire length of the protective fence at the time of impact.

<6.1> Structure of Stay Rope in Guard Fence As shown in FIG. 1, the stay rope 40 is positioned on both sides of each strut 10 with the tension control device 30 provided on the extending portion 11 of each strut 10. It is a rope member that is continuously routed between the upper sides of the protective net 20 and between the terminal support 10 </ b> A and the side anchors 45.
In this example, the stay rope 40 includes a hanging portion 41 that is obliquely arranged between each tension control device 30 and the upper side of the protective net 20, a horizontal portion 42 that is arranged parallel to the upper side of the protective net 20, The form which has the reservation rope part 43 arrange | positioned between the terminal support | pillar 10A and the side anchor 45 is demonstrated.
The horizontal portion 42 can be replaced by an upper rope of the protective net 20.
The stay rope 40 is not limited to a single continuous rope, and may be composed of a plurality of rope members.
The point is that the stay rope 40 may be arranged so that the impact force acting on the receiving span can be sequentially transmitted toward the terminal column 10A.

<6.2> Cabling Structure of Stay Rope in Followed Restraint Mechanism With reference to FIG.
The stay rope 40 is routed in an M shape by spanning one rocking rope 53a having a height difference, the center rope 51, and the other rocking rope 53b in this order.
Both ends of the stay rope 40 extending obliquely downward outside the tension control device 30 are connected to the upper side of the protective net 20 on both sides of the support column 10A (10B).

[Protective fence receiving characteristics]
Next, the receiving characteristics of the protective fence will be described.

<1> Tension control device before impact FIG. 5A shows a model diagram of the tension control device 30 before impact.
The left and right suspension portions 41, 41 of the stay rope 40, which are arranged in an M shape on the three ropes 53a, 51, 53b constituting the driven restraint mechanism 50, extend from the tension control device 30 to the outside and are adjacent to each other. It is connected to the upper side of the protection net of the span.
Before the impact, equal tensile forces T ₁ and T ₂ corresponding to the weight (dead load) of the protective net 20 located on both sides of the support column are applied to the left and right suspension parts 41 and 41.
Tensile forces T ₁ and T ₂ opposite to each other act on the stay rope 40 moored to the driven restraining mechanism 50, so that the stay rope 40 moored to the driven restraining mechanism 50 can be turned into the rocking ropes 53a and 53b and the braking surface 32a. It is restrained by the peripheral surface.
Before the impact, the tension control device 30 does not exhibit a damping function because the balance between the tensile forces T ₁ and T ₂ generated in the stay rope 40 and the restraining force of the stay rope 40 by the driven restraining mechanism 50 is maintained. .

<2> Tension control device at the time of impact The operation of the tension control device 30 at the time of impact will be described with reference to FIG.
FIG. 5B shows the tension control device 30 provided on the intermediate strut 10B on the left side as viewed from above the slope among the intermediate struts 10B (or terminal struts 10A) on both sides of the receiving span.

The tensile force T ₃ of suspender 41 of the right side of the stay ropes 40 linked to受撃span increases, tension difference between the tensile force T ₄ of the suspender 41 of the left linked to the adjacent span (T ₃ > T ₄ ).
As the tension difference is generated in the tensile forces T ₃ , T ₄ of the left and right suspension parts 41, 41, the tension control device 30 exhibits a damping function as described in detail below, and the tension force of the right suspension part 41 T ₃ is attenuated and transmitted to the left hanging portion 41.

<2.1> Restraint of rope In the tension control device 30, the tensile force acting on the right hanging portion 41 is not directly transmitted to the left hanging portion 41 but attenuated and transmitted.
The damping action of the tensile force will be described in detail.
Tension T ₃ of suspender 41 of the rightward, when transmitted to the stay rope 40 which is anchored to the driven restraining mechanism 50, the central Sakuwa 51 is lifted directly above, a pair of swing links 55a Accordingly, 55b are opened Swings in the angular direction.
When the pair of swing links 55a and 55b swings in the opening angle direction, the restraining force (tightening force) of the stay rope 40 located between the peripheral surfaces of the swinging ropes 53a and 53b and the braking surface 32a. The resistance friction between the braking surface 32a and the stay rope 40 increases gradually.

In particular, since the restraining force of the stay rope 40 acts on the curved braking surface 32a through the swing links 55a and 55b positioned in the radial direction, the axial force of the swing links 55a and 55b is utilized to the maximum extent. The stay rope 40 can be restrained.
Note that no bending force is generated in the swing links 55a and 55b while the stay rope 40 is restrained.

<2.2> Sliding of the stay rope When the pair of swing links 55a and 55b swings, sliding friction is generated between the outer peripheral surface of the stay rope 40 and the braking surface 32a. The tensile force (impact force) of 40 is attenuated.

  When the stay rope 40 slides, the rocking ropes 53a and 53b rotate. Therefore, even if the stay rope 40 is strongly crushed to the limit of the breaking strength, the stay rope 40 does not fall out of slidability.

<2.3> Differences from conventional shock absorbers In conventional friction sliding shock absorbers, when the tension of the rope element reaches a certain value, sliding starts, and the restraining force of the rope element during sliding Is constant.
The tensile force of the rope element shows a maximum value at the start of sliding, and immediately after that, the tensile force decreases, and the tensile force decreases while going up and down for a while.
When the rope element is connected to the top of the column, the maximum tensile force of the rope element is instantaneously transmitted to the top of the column immediately after receiving, and there is a risk that the column top will break.

On the other hand, in the tension control device 30 of the present invention, the sliding is started only by a small tension difference between the left and right suspension parts 41, 41 of the stay rope 40, and the restraining force of the stay rope 40 during the sliding is the stay force. It changes according to the magnitude of the generated tension of the rope 40.
That is, when transmitting the tension from the right suspension 41 to the left suspension 41 through the stay rope 40 moored to the driven restraint mechanism 50, the tension is initially transmitted as a small tension and gradually increased until reaching the maximum tension. Since the tension is transmitted, damage to the receiving span can be reduced.
Since part of the tensile force is transmitted to the adjacent span while the tensile force is being attenuated by the tension control device 30 provided on the strut 10B (10A) of the receiving span, the load burden of the strut 10B (10A) in the receiving span Is reduced, and there is no risk that the top of the column 10B (10A) is destroyed.

  Furthermore, in the conventional shock absorber, it is necessary to manage the tightening force of a plurality of tightening bolts, and it is necessary to properly use a plurality of types of shock absorbers having different shock absorbing performances. It is not necessary to manage the restraining force of the stay rope 40 or use the tension control device 30 properly.

<2.4> Stay rope tension difference The difference in tension between the left and right suspension parts 41, 41 of the stay rope 40 moored to the driven restraint mechanism 50 is not constant, depending on the magnitude of the tensile force generated in the receiving span. Change.
That is, in the tension control device 30, a small tension difference is generated for a small tension, and a large tension difference is generated for a large tension.

<2.5> Damping performance of tension control device At the time of impact, a tension difference (T ₃ -T ₄ ) is generated in the left and right hanging parts 41, 41, and the tensile force of the tension difference between the left and right hanging parts 41, 41 Is attenuated.
As described above, the tension control device 30 has a structure in which the restraining force of the stay rope 40 changes according to the magnitude of the generated tensile force of the stay rope 40, and thus can control the damping performance arbitrarily.
By adjusting the link length of the pair of swing links 55a, 55b, the curvature of the braking surface 32a, the eccentric distance between the center of the braking surface 32a and the support shaft 52 of the central ring 51 in the vertical direction, etc. The attenuation performance of the device 30 can be selected.

<2.6> Damage to Stay Rope When the stay rope 40 slides, the rocking ropes 53a and 53b rotate.
Therefore, the stay rope 40 moored to the rocking ropes 53a and 53b slides between the peripheral surfaces with the braking surface 32a, but does not slide between the circumferential surfaces with the rocking ropes 53a and 53b. .
Therefore, damage to the stay rope 40 can be reduced during the operation of damping the tensile force, and it is possible to cope with a large slide length of the stay rope 40.

<3> Transmission of tensile force through stay rope In FIG. 1, the tensile force of the stay rope 40 is attenuated by the tension control device 30 in the receiving span, and the attenuated tensile force is transmitted to the stay rope 40 in the adjacent span.
Similarly, in the adjacent span, the tension control device 30 attenuates the tension and further transmits it to the stay rope 40 of the adjacent span.
When the impact force such as falling rocks is large, the impact force is transmitted in a chained manner while being attenuated toward the terminal column 10A through the stay rope 40.

<4> Strut load of strut Since the tension control devices 30 and 30 having a damping function are installed on both sides of the receiving span, the load burden on the intermediate strut 10B located on both sides of the receiving span is reduced.
Also in each adjacent span, the tensile force generated in the stay rope 40 is attenuated and gradually decreases in the process of transmitting the tensile force in a chain, so that each strut (intermediate strut 10B, terminal strut) to which the tension control device 30 is attached. The load burden of 10A) is reduced.
Therefore, the cross-sectional performance of each required column (intermediate column 10B or terminal column 10A) can be reduced.
When the stay rope 40 of the stay rope 40 is connected to the side anchor 45, the required anchor strength of the side anchor 45 can be reduced.
Therefore, the cost of the protective fence can be greatly reduced.

<5> Sustainability of damping function In the conventional shock absorber, it is necessary to replace the rope element once it slides and exhibits the damping function.
On the other hand, the tension control device 30 of the present invention can exhibit the same damping performance any number of times even after the damping function is exhibited.

<6> Suppression of deformation in height direction of blocking surface by stay rope Suspension portion 41 of stay rope 40 lifts the upper side of protective net 20.
Therefore, when the protection net 20 is deformed to project to the valley side, even if the blocking surface of the protection net 20 attempts to shrink in the height direction, the hanging portion 41 of the stay rope 40 is deformed (blocked) in the height direction of the blocking surface. Effective reduction of the effective height of the surface).

  In the following, other embodiments will be described. In the description, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

Although not shown, a stopper that restricts the uppermost position of the support shaft 52 that is the pivot of the swing links 55a and 55b may be added to the driven restraining mechanism 50.
By providing a stopper that regulates the uppermost position of the support shaft 52 above the up and down support shaft 52, the maximum sliding force of the stay rope 40 can be adjusted.
The stopper may have a structure that can regulate the uppermost position of the support shaft 52 rising along the guide hole.
Moreover, you may comprise so that adjustment of the uppermost position of the spindle 52 is possible in combination with an adjustment bolt.
In this example, the ascending position of the support shaft 52 can be regulated, so that excessive tightening of the stay rope 40 can be prevented, and damage to the stay rope 40 during sliding can be reduced.

<1> Tension Control Device FIG. 6 shows another tension control device 30 in which a spring 56 that constantly urges the support shaft 52 downward is added to the driven restraining mechanism 50.
In this example, a configuration is shown in which a spring 56 is stretched between the reaction force member 57 provided directly below the support shaft 52 and the support shaft 52. However, the stationary member 57 provided directly above the support shaft 52 and the support shaft are shown. The spring 56 may be contracted between 52.
In short, any structure may be used as long as a spring force is always applied to the support shaft 52 which is the swing center of the pair of swing links 55a and 55b.
The central rope 51 rises along the guide hole while resisting the spring force of the spring 56, and the pair of left and right rocking ropes 53 a and 53 b restrain the stay rope 40 while receiving the spring force of the spring 56. .

<2> Effects of this example The basic effects of this example are the same as those of the first embodiment.
In this example, the frictional force between the stay rope 40 and the peripheral surface of the braking surface 32 a of the peripheral wall 32 can be varied by the spring force of the spring 56.
That is, there is an effect that the frictional force at the start of sliding of the moored stay rope 40 can be reduced or the maximum frictional force can be controlled without changing the member or structure of the tension control device 30. .
In addition, even after the tension control device 30 exhibits a damping function by providing the spring 56, the swing links 55a and 55b are returned to their home positions, and the tension control device 30 is not repaired at all and repeated any number of times. Can be used.

<1> Tension Control Device FIG. 7 shows another tension control device 30 in which a bolt 58 capable of adjusting the height position of the support shaft 52 is additionally provided in the driven restraint mechanism 50.
In this example, a bolt 58 is screwed to a reaction force member 57 provided directly below the support shaft 52, and the tip of the bolt 58 is connected to the support shaft 52. However, a stationary member is directly above the support shaft 52. 57 and a bolt 58 may be provided.
By rotating the bolt 58 and adjusting the height position of the support shaft 52, the frictional force between the stay rope 40 and the peripheral surface of the braking surface 32a of the peripheral wall 32 can be arbitrarily adjusted.
For example, if the support shaft 52 is pushed up with the bolt 58, the frictional force between the stay rope 40 and the peripheral surface of the braking surface 32a of the peripheral wall 32 increases.

<2> Effects of this example The basic effects of this example are the same as those of the first embodiment.
In this example, it is possible to generate a frictional force from the time when the tension of the stay rope 40 moored to the tension control device 30 is generated, and the stay rope 40 starts to slide when a constant tensile force is reached.
Further, in this example, since the bolt 58 regulates the height of the support shaft 52 to a fixed position, the sliding starts when the tension is generated, and when the frictional force reaches a constant value, the bolt 58 can slide while maintaining the frictional force. The effects are as follows.
In this example, it is possible to set the sliding start tension and the maximum sliding force of the stay rope 40 without modifying the tension control device 30 or exchanging some components.

The tension control device 30 may be configured by appropriately combining the previously described Examples 2 to 4.
For example, a combination of the second embodiment in which the uppermost position of the support shaft 52 is restricted to a specific position and the third embodiment in which a spring 56 that biases the support shaft 52 directly downward is combined, thereby damping by the tension control device 30. The performance can be controlled more finely.

In the first to fifth embodiments, the configuration in which the central rope 51 is configured to be movable up and down together with the support shaft 52 has been described. However, as shown in FIG. You may provide in a position.
In this example, the pair of swing links 55a and 55b swings around the support shaft 52 at a fixed position.
The action of the tension control device 30 is different from that of the first embodiment only in that the central rope 51 does not rise, and other damping actions are the same as those of the first embodiment.

  In the first embodiment, the tension control device 30 is disposed in the extending portion 11 of each support column 10A, 10B, and the left and right hanging portions 41 of the stay rope 40 are connected to the upper side of the protection net 20 of the adjacent span. However, the tension control device 30 may be arranged on the upper portions of the support pillars 10A and 10B from which the extension portion 11 is omitted, and the stay rope 40 moored to the tension control device 30 may be horizontally laid to form a protective fence.

In the first embodiment, the stay rope 40 is provided at the end of the stay rope 40 and the stay rope section 43 is connected to the side anchor 45. However, the stay rope section 43 and the side anchor 45 are omitted, The end of the stay rope 40 may be connected to the terminal column 10A to form a protective fence.
In the case of this example, the tension control device 30 is installed on the upper part of the intermediate column 10B and is not installed on the terminal column 10A.
The effects of the stay rope 40 and the tension control device 30 are the same as those of the first embodiment.

  In this example, it is suitable as a protective fence for medium and small scales that has a small impact force such as a falling rock and does not require a side anchor.

10 .... post 10A ... terminal post 10B ... intermediate post 20 ... protection net 21 ... rope material 22 ... continuous ring element 23 ... closing buffer 24 ··· Connection buffer 30 ··· Tension control device 31 ··· Substrate 32 ··· Perimeter wall 32a · Perimeter wall braking surface 33 ··· Opening 34 ··· Guide hole 40 ··· Stay rope 41 ··· Stay rope hanger 42 · · · Stay rope horizontal portion 43 · · · Stay rope stay rope portion 50 · · · Follow-up restraint mechanism 51 ··· Central rope 52 ··· Support shaft 53a · Swing rope 53b · Swing rope 54 · · · Spindle 55a · Swing link 55b · Swing link

Claims (14)

A tension control device that is attached to the upper part of a pillar constituting the protective fence and slidably anchors a rope element spanned between at least the upper part of the pillar and the upper side of the protective net located on both sides of the pillar,
A fixed peripheral wall installed at the top of the column and having a braking surface curved on the inner surface;
It consists of a driven restraint mechanism arranged inside the peripheral wall,
A pair of swing links in which the driven restraining mechanism is pivotally supported at a lower end portion and arranged in a V shape;
A central rope supported on the lower end pivot of the pair of swing links;
A swinging rope that is pivotally supported at the upper end of each swinging link;
The central rope is positioned between the pair of rocking ropes and lower than the rocking rope;
A portion of the rope element arranged in an M shape between the plurality of rocking ropes and the central rope is sandwiched and restrained between the circumferential surfaces of the rocking rope and the braking surface of the peripheral wall;
The pair of oscillating links oscillate about the lower end pivotal support portion, so that the restraining force of the rope element between the oscillating rope and the braking surface of the peripheral wall according to the magnitude of the generated tensile force of the rope element. Is configured to be controllable,
Tension control device.   The braking surface of the peripheral wall is curved so that the opposing distance between the rocking rope and the braking surface of the peripheral wall gradually decreases as the pair of swing links swing along the opening angle direction. The tension control device according to claim 1.   Each of the pair of swings constituting the driven restraint mechanism such that the braking surface of the peripheral wall is an arcuate surface and the center of the lower end pivot part of the pair of swing links is located below the center of the braking surface of the peripheral wall. The tension control device according to claim 1, wherein a total length of the link and a radius of the peripheral wall are related to each other.   The tension control device according to claim 1 or 2, wherein a radius of curvature of a braking surface of the peripheral wall gradually decreases along an opening angle direction of the pair of swing links.   The lower end pivot support part of the pair of swing links can be raised and lowered, and the pair of swing links swings about the lower end pivot support part in conjunction with the vertical movement of the central rope. The tension control device according to any one of 1 to 4.   6. The tension control device according to claim 5, wherein the driven restraining mechanism includes guide means for restricting the moving direction of the central rope only in the vertical direction.   The tension control device according to claim 5 or 6, wherein the driven restraining mechanism includes a stopper that regulates the uppermost position of the lower end pivotal support portion of the pair of swing links.   The tension control device according to any one of claims 5 to 7, wherein the driven restraint mechanism includes a spring that constantly biases the lower end pivot portions of the pair of swing links toward directly below.   The tension control device according to claim 5 or 6, wherein the driven restraining mechanism includes a bolt capable of adjusting a height position of a lower end pivotal support portion of the pair of swing links.   5. The tension control device according to claim 1, wherein the lower end pivotally supporting portions of the pair of swing links are pivotally supported at a fixed position so as not to move up and down. Multiple struts erected on the foot of the mountain at a predetermined interval, protective nets laid horizontally between these struts, tension control devices installed above each strut, and both sides of each tension control device and each strut A protective fence comprising a rope element arranged between the upper side of the protective net located,
Using the tension control device according to any one of claims 1 to 10,
Connecting both ends of the rope element extending to the outside of the tension control device to the upper side of the protective net located on both sides of each column in span units;
The tensile force generated in the rope element at the time of receiving is attenuated by the tension control device, and the tensile force is transmitted while being attenuated in a chain manner from the receiving span to the adjacent span through the rope element. ,
Guard fence.   The end of the rope element arranged on the upper side of the protective net is connected to the side anchor so that the tensile force generated in the rope element at the time of impact can be transmitted to the side anchor provided on the side of the terminal column. The protective fence according to claim 11, wherein:   Install a tensile force control device at the upper part of each strut above the upper side of the protective net and obliquely route both ends of the rope element moored to the tension control device to the upper side of the protective net located on both sides of each post. The protective fence according to claim 11 or 12, characterized by being connected by   The protective fence according to claim 11 or 12, wherein the rope element moored to the tension control device is horizontally mounted.

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