Patent Application
20110297907
The present invention relates to a shock-absorbing device for a net body of a guard fence.
Conventionally, as one of the examples of a guard fence employing such shock-absorbing device for net body, there has been known a guard fence comprising: a concrete base provided on a boundary between an inclined plane and a road; poles disposed on such concrete base at predetermined intervals; and a guard net stretched between those poles in the form of a band (e.g., see patent document 1)
Further there has been known a guard fence comprising: poles provided at predetermined intervals; horizontal rope members provided between such poles; and a shock-absorbing portion formed in a mid section of the horizontal rope member, in which a net made of wire is hooked on the horizontal rope members so as to cover the space between the poles, and the shock-absorbing portion comprises an extra length portion formed by bending the horizontal rope member in a mid section thereof and a clamping instrument for clamping the extra length portion with a certain amount of force (e.g., see patent document 2). Furthermore, there has been known a guard fence in which transverse rods made of concrete, metal or the like are provided between the poles in the form of multiple rows. Furthermore, there has been known a guard fence in which an alternate rope member is used to link an upper portion of the pole to an inclined plane in front of the pole, and a shock-absorbing instrument for slidably containing the alternate rope member is provided in a mid section of the alternate rope member (e.g., see patent document 3).
Furthermore, there has been known a guard fence in which transverse supporting ropes are provided between the poles, and an end portion holder is used to hold a turn-back portion of a net rope composing a net body and the supporting rope so as to damp an impact energy (e.g., see patent document 4).
Patent document 1: Laid-open Japanese patent publication No. 2003-3425
Patent document 2: Laid-open Japanese patent publication No. Hei-6-173221
Patent document 3: Laid-open Japanese patent publication No. 2000-273827
Patent document 4: Laid-open Japanese patent publication No. Hei-7-252808
According to the guard fence disclosed in the patent document 4, although the net body is capable of absorbing a force of impact by friction sliding, the amount of deformation of the net body as a whole is small. By enlarging the amount of deformation of the net body, not only the damping effect on the impact energy can be improved, but the amount of the force applied to the poles can also be reduced.
Therefore, it is an object of the present invention to provide a shock-absorbing device for net body of guard fence, capable of improving a net body's effectiveness of absorbing an impact energy by enlarging the amount of deformation of the net body when the net body has been subjected to a force of impact due to rockfall, mudslide, avalanche and the like.
The present invention is for use in a guard fence comprising: poles vertically installed at intervals; a net body provided between the poles; and a shock-absorbing instrument holding a shock-absorbing rope member. The net body has a net body turn-down portion formed by turning down wires on an edge portion thereof, and a net body intersecting portion in which the wires intersect with each other. By using the shock-absorbing rope member and the shock-absorbing instrument, the net body turn-down portion or the net body intersecting portion can be linked to linkage members provided on the guard fence other than the net body, and the shock-absorbing rope member is allowed to friction slide with respect to the shock-absorbing instrument as the net body moves, thereby absorbing a force of impact applied to the net body.
Further, according to the present invention, a shock-absorbing turn-back loop is formed by allowing the shock-absorbing instrument to hold an end portion of a shock-absorbing turn-back portion formed by turning back the shock-absorbing rope member. Such shock-absorbing turn-back loop is linked to the linkage member, and the net body turn-down portion or the net body intersecting portion is fastened to the shock-absorbing turn-back loop.
Furthermore, according to the present invention, a loop portion is formed by curling back the shock-absorbing rope member toward itself, and the shock-absorbing instrument is used to hold a folded portion of the shock-absorbing rope member. The linkage member and the shock-absorbing turn-back portion or the net body intersecting portion are linked to each other by means of such loop portion.
Furthermore, according to the present invention, the shock-absorbing rope member is inserted through mesh patterns of a plurality of net body turn-down portions or net body intersecting portions, followed by turning back two end portions of such shock-absorbing rope member in opposite directions and allowing a turn-back portion to be fastened to a linkage portion of the guard fence. The end portions arranged in opposite directions are then laid one on top of another, and the shock-absorbing instrument is used to hold such overlapping portion.
Furthermore, according to the present invention, the shock-absorbing rope member is inserted through mesh patterns of a plurality of net body turn-down portions or net body intersecting portions. And, the linkage member of the guard fence is provided with the shock-absorbing instruments corresponding to the two end portions of the shock-absorbing rope member, respectively, thereby allowing the shock-absorbing instruments on both ends to hold the two end portions of the shock-absorbing rope member, respectively.
Furthermore, according to the present invention, the linkage member is a pair of linking rope members provided on the guard fence and distant from each other. A turning back portion formed by turning back a front end portion of the shock-absorbing rope member is movably fastened to one and the other linking rope members of the pair of the linking rope members, respectively. The net body turn-down portion or the net body intersecting portion is linked to the front end portion, and an extra length portion is provided on the other side of the shock-absorbing rope member. The extra length portions of one and the other shock-absorbing rope members are laid one on top of another, and the shock-absorbing instrument is used to hold such overlapping portion.
According to the aforementioned structure, once the net body has been subjected to an impact energy due to rockfall or the like, the shock-absorbing instrument will friction slide along the shock-absorbing rope member as the net body turn-down portion or the net body intersecting portion moves, thereby absorbing the impact energy. In addition, the amount of deflection of the net body becomes large as the shock-absorbing instrument moves, thus making it possible to provide a guard fence superior in absorbing the impact energy effectively.
Further, since the net body turn-down portion or the net body intersecting portion is used for linking, the linking operation for linking the net body to the guard fence becomes easy.
Preferable embodiments of the present invention are described in detail with reference to the accompanying drawings.
An embodiment 1 of the present invention is described hereunder with reference to
On an upper and a lower portions of the poles 3, there are stretched an upper and a lower transverse rope members 11, 12, respectively. Further, on rear sides of the upper and lower portions of the poles 3, there are respectively provided an upper and a lower fastening portions 13, 14 to which the upper and lower transverse rope members 11, 12 are detachably fastened. And, end portions of the upper and lower transverse rope members 11, 12 are linked to the fastening portions 13, 14 of the poles 3, 3 at both ends.
However, no other transverse rope member is provided between the upper and lower transverse rope members 11, 12.
As shown in
The diameter of the wire member 22 of the wire net 21 is 9 to 14 mm, and the tension strength thereof is 30 to 90 kN. Further, a width W corresponding to a diagonal line of each mesh pattern of the wire net 21 is 300 to 600 mm.
The wire net 21 is linked to the upper transverse rope member 11 serving as a linkage member by means of a shock-absorbing instrument 30 and a shock-absorbing rope member 40 made of a wire rope.
As shown in
As shown in
Also, the aforementioned net body turn-down portion 24 is inserted through the shock-absorbing turn-back loop 42, thereby allowing the shock-absorbing turn-back loop 42 to be fastened to the shock-absorbing instrument 30. Further, the shock-absorbing turn-back loop 42 and the upper transverse rope member 11 are detachably linked to one another by a shackle 45 serving as a detachable linking means.
As shown in
Furthermore, on a lower edge of the wire net 21, the net body turn-down portion 24 and the lower transverse rope member 11 are linked together by means of the shackle 45. In addition, the wire net 21 is allowed to move in the longitudinal directions of the transverse rope members 11,12 and a longitudinal rope member described later by using the shackle 45.
Also, in this case, the shock-absorbing rope member 40 and the shock-absorbing instrument 30 compose a shock-absorbing structure 48.
As shown in
Next, as shown in
In this case, the wire net 21 is so wide in the left-right direction that the width thereof is substantially identical to an interval formed by the pole 3 in the center and the poles 3 at both ends. Further, the wire net 21 has the net body turn-down portion 24 located on both the left and right edges thereof.
Furthermore, as shown in
Here, the longitudinal rope member 52 servers as a core member and allows the shock-absorbing rope member 40 to be stretched with a predetermined tension force.
Further, as shown in
Further, on an outward side of the left-right direction of the poles 3 at both ends, an alternate rope member linking portion 72 is fixed on an upper surface of the aforementioned concrete base 2 by means of an anchor 71. Such alternate rope member linking portion 72 is linked to the corresponding upper portions of the poles 3 at both ends by an alternate rope member 73.
In addition, an anchor 74 is buried in an inclined plane which is a ground surface in front (mountain side) of all the poles 3. Such anchor 74 is linked to the upper portion of the pole 3 by an alternate rope member 75. In this case, a round bar 76 serving as a fastening portion is inserted through the upper portion of the pole 3 in a manner such that end portions thereof protrude from the pole 3 toward the left-right direction. The alternate rope member 75 is so wound around the pole 3 that it is fastened to upper sides of the two end portions of the round bar 76. And then, a superposition portion 75K of the alternate rope member 75 thus wound is bound by a wire clip 77 serving as a binding means, in front of the pole 3. In this way, the alternate rope member 75 is allowed to be linked to the upper portion of the pole 3.
Further, as shown in
Operation regarding the abovementioned structure is described hereunder. With regard to the upper transverse rope member 11, once the net body 4 has been subjected to a force of impact due to rockfall, mudslide, avalanche and the like, a tension force will be generated on the wire net 21, and a force pulling the net body turn-down portion 24 downward will also be applied to the wire net 21. Therefore, the shock-absorbing instrument 30 to which the net body turn-down portion 24 is fastened will friction slide along the extra length portion 44, and thus absorb the force of impact. Further, the amount of deflection of the wire net 21 becomes large as the shock-absorbing instrument 30 moves, thereby improving the effectiveness of absorbing the force of impact, and thus reducing the force applied to the pole 3 or the like.
Further, once the shock-absorbing instrument 30 has come into contact with the stopper 43 after friction sliding along the extra length portion 44, the shock-absorbing instrument 30 will stop friction sliding. Therefore, the force of impact is then absorbed by virtue of the tension force of the shock-absorbing rope member 40.
Further, with regard to the poles 3 at both ends, once the net body 4 has been subjected to a force of impact due to rockfall, mudslide, avalanche and the like, a tension force will be generated on the wire net 21, and a force pulling the net body turn-down portion 24 toward the center will also be applied to the wire net 21. In this way, a tension force will be applied to the shock-absorbing rope member 40 to which the net body turn-down portion 24 is fastened, and the shock-absorbing rope member 40 having a loop-like shape as a whole will be subjected to the tension force, thereby allowing the extra length portions 44, 44 serving as the end portions to friction slide with respect to the shock-absorbing instrument 30, and thus allowing the force of impact to be absorbed. In addition, as the shock-absorbing rope member 40 having a loop-like shape as a whole is enlarged, the amount of deflection of the wire net 21 becomes large, thereby improving the effectiveness of absorbing the force of impact, and thus reducing the force applied to the pole 3 or the like.
Similarly, with regard to the pole 3 in the center, once the net body 4 has been subjected to a force of impact due to rockfall, mudslide, avalanche and the like, a tension force will be generated on the wire nets 21, 21 located on both sides of the pole 3. Namely, a force trying to pull the net body turn-down portion 24 away from the pole 3 will be applied to the wire nets 21, 21, thereby applying a tension force to the shock-absorbing rope member 40 to which the net body turn-down portion 24 is fastened, and thus applying the tension force to the shock-absorbing rope member 40 having a loop-like shape as a whole. In this way, the extra length portions 44, 44 serving as the end portions are allowed to friction slide with respect to the shock-absorbing instrument 30, thereby allowing the force of impact to be absorbed. Further, as the shock-absorbing rope member 40 having a loop-like shape as a whole is enlarged, the amount of deflection of the wire nets 21, 21 located on both sides becomes large, thereby improving the effectiveness of absorbing the force of impact, and thus reducing the force applied to the pole 3 or the like. In addition, with regard to the pole 3 in the center, when one of a left and a right wire nets 21 has been subjected to the force of impact, such force of impact will be transmitted to the other wire net 21 by virtue of the shock-absorbing rope member 40, thereby distributing the force of impact.
In this sense, the present embodiment is suitable for use in the guard fence comprising poles 3, 3 vertically installed at the predetermined intervals, the net body 4 provided between the poles 3, 3 and the shock-absorbing instrument 30 holding the shock-absorbing rope member 40. The net body 4 has the net body turn-down portion 24 on an edge portion thereof, in which the oblique wire member 22 serving as a wire member is turned down, and the net body intersecting portion 23 in which the oblique wire members 22 intersect with one another. By using the shock-absorbing rope member 40 and the shock-absorbing instrument 30, the net body turn-down portion 24 or the net body intersecting portion 23 can be linked to the upper transverse rope member 11 or the longitudinal rope member 52 other than the net body 4, both of which serve as the linkage members provided on the guard fence 1. The shock-absorbing rope member 40 slides with respect to the shock-absorbing instrument 30 as the net body 4 moves, thereby absorbing a force of impact applied to the net body 4. Namely, once an impact energy due to rockfall and the like has been applied to the net body 4, the shock-absorbing instrument 30 will friction slide along the shock-absorbing rope member 40 due to the net body turn-down portion 24 or the net body intersecting portion 23 so as to absorb the impact energy. In addition, the amount of deflection of the net body 4 becomes large as the shock-absorbing instrument 30 moves, thereby improving the effectiveness of absorbing the impact energy.
Further, according to the present embodiment, the shock-absorbing turn-back loop 42 is formed by allowing the shock-absorbing instrument 30 to hold the end portion of the shock-absorbing turn-back portion 41 formed by turning back the shock-absorbing rope member 40. The shock-absorbing turn-back loop 42 is linked to the upper transverse rope member 11 serving as the linkage member, and the net body turn-down portion 24 or the net body intersecting portion 23 is fastened to such shock-absorbing turn-back loop 42. Therefore, once an impact energy due to rockfall or the like has been applied to the net body 4, the shock-absorbing instrument 30 will friction slide along the shock-absorbing rope member 40 due to the net body turn-down portion 24 or the net body intersecting portion 23 fastened to the shock-absorbing instrument 30, thereby absorbing the impact energy. In addition, the amount of deflection of the net body 4 becomes large as the shock-absorbing instrument 30 moves, thereby improving the effectiveness of absorbing the impact energy.
Furthermore, according to the present embodiment, the net body turn-down portion 24 or the net body intersecting portion 23 is inserted into and fastened to the shock-absorbing turn-back loop 42, thereby allowing the net body turn-down portion 24 or the net body intersecting portion 23 to be fastened to the shock-absorbing instrument 30, thud obtaining a shock-absorbing device with a simple structure.
Furthermore, according to the present embodiment, the shock-absorbing rope member 40 is inserted through a plurality of the mesh patterns of the net body turn-down portions 24 or the net body intersecting portions 23. The two end portions 40T, 40T of the shock-absorbing rope member 40 are turned back in opposite directions, and the portions at which the two end portions 40T, 40T are thus turned back are fastened to the pin bolts 51, 51 serving as the linkage portions of the guard fence 1. Such end portions 40T, 40T in opposite directions are laid one on top of another, and the shock-absorbing instrument 30 is used to hold the portion in which the end portions 40T, 40T are thus laid one on top of another. Therefore, once an impact energy due to rockfall or the like has been applied to the net body 4, a tension force will be applied to the shock-absorbing rope member 40 inserted through a plurality of the mesh patterns of the net body turn-down portions 24 or the net body intersecting portions 23. Thus, the end portions 40T, 40T of the shock-absorbing rope member 40 are allowed to friction slide with respect to the shock-absorbing instrument 30 so as to absorb the impact energy, said shock-absorbing instrument 30 holding the portion in which the two end portions 40T, 40T are laid one on top of another. In addition, the amount of deflection of the net body 4 can become large as the shock-absorbing rope member 40 friction slides, thereby improving the effectiveness of absorbing the impact energy.
Furthermore, as an effect of the present embodiment, the shock-absorbing rope member 40 is fastened to a plurality of the net body turn-down portions 24 on the edge of the wire net 21, thereby allowing the edge of the wire net 21 to be linked to the pole 3 with one shock-absorbing rope member 40.
An embodiment 2 of the present invention is shown in
In addition, other than the upper transverse rope member 11, the lower transverse rope member 12 and the net body turn-down portion 24 on a lower end of the wire net 21 can be linked together. Also, the longitudinal rope member 52 and the net body turn-down portion 24 on either the left or right edge of the wire net 21 can be linked together as well. In this case, the lower transverse rope member 12 and the longitudinal rope member serve as the linkage members. Further, the net body intersecting portion 23 may be inserted into and fastened to the shock-absorbing turn-back loop 42.
And then, once the wire net 21 has been subjected to a force of impact, and a force stronger than a predetermined force has been applied to the shock-absorbing instrument 30 by the net body turn-down portion 24, one extra length portion 44 will friction slide with respect to the shock-absorbing instrument 30 so as to absorb the force of impact, and the wire net 21 will move away from the upper transverse rope member 11 as the shock-absorbing instrument 30 moves. Therefore, the amount of deformation of the net body 4 becomes large, thus absorbing the force of impact also.
Further, in this case, the one extra length portion 44 slides with respect to the shock-absorbing instrument 30 and friction slides with respect to the main body 46 of the shackle 45 at the same time, thereby making it possible to partially absorb the force of impact even with the friction slide taken place between the extra length portion 44 and the main body 46.
An embodiment 3 of the present invention is shown in
In addition, other than the upper transverse rope member 11, the lower transverse rope member 12 and the net body turn-down portion 24 on the lower end of the wire net 21 can be linked together. Also, the longitudinal rope member 52 and the net body turn-down portion 24 on either the left or right edge of the wire net 21 can be linked together as well. In this case, the lower transverse rope member 12 and the longitudinal rope member serve as the linkage members. Further, the net body intersecting portion 23 may be inserted into and fastened to the openable hook 81. Furthermore, the openable hook 81 is provided on the shock-absorbing instrument 30 in the embodiment 2, and the net body turn-down portion 24 or the net body intersecting portion 23 may be fastened to such openable hook 81.
And then, once the wire net 21 has been subjected to a force of impact, and a force stronger than a predetermined force has been applied to the shock-absorbing instrument 30 by the net body turn-down portion 24, the extra length portions 44, 44 will friction slide with respect to the shock-absorbing instrument 30 so as to absorb the force of impact, and the wire net 21 will move away from the upper transverse rope member 11 as the shock-absorbing instrument 30 moves. Therefore, the amount of deformation of the wire net 21 becomes large, thus absorbing the force of impact also.
Further, according to the present embodiment, the openable hook 81 serving as the fastening portion is provided on the shock-absorbing instrument 30 for allowing the net body turn-down portion 24 or the net body intersecting portion 23 to be fastened thereto. In this sense, the net body turn-down portion 24 or the net body intersecting portion 23 can be fastened to the shock-absorbing instrument 30 and the shock-absorbing turn-back loop 42 by means of such openable hook 81, thereby obtaining a shock-absorbing device with a simple structure.
An embodiment 4 of the present invention is shown in
In addition, other than the upper transverse rope member 11, the lower transverse rope member 12 and the net body turn-down portion 24 on the lower end of the wire net 21 can be linked together. Also, the longitudinal rope member 52 and the net body turn-down portion 24 on either the left or right edge of the wire net 21 can be linked together as well. In this case, the lower transverse rope member 12 and the longitudinal rope member 52 serve as the linkage members.
And then, once the wire net 21 has been subjected to a force of impact, and a force stronger than a predetermined force has been applied to the shock-absorbing loop 63 by the net body turn-down portion 24, the extra length portions 44, 44 in opposite directions will friction slide with respect to the shock-absorbing instrument 30 so as to absorb the force of impact, and the wire net 21 will move away from the upper transverse rope member 11 as the shock-absorbing loop 63 enlarges due to the friction slide of the extra length portions 44, 44. Therefore, the amount of deformation of the wire net 21 becomes large, thus absorbing the force of impact also.
Further, according to the present embodiment, the shock-absorbing loop 63 serving as a loop portion is formed by curling the shock-absorbing rope member 40, and the shock-absorbing instrument 30 is used to hold the portion in which the shock-absorbing rope member 40 is folded, thereby allowing the upper transverse rope member 11 and the shock-absorbing turn-back portion 24 or the net body intersecting portion 23 to be linked together by means of the shock-absorbing loop 63. Therefore, once an impact energy due to rockfall or the like has been applied to the net body 4, the shock-absorbing loop 63 linked to the upper transverse rope member 11 and the net body turn-down portion 24 or the net body intersecting portion 23 will be subjected to a force trying to enlarge the shock-absorbing loop 63 itself. Thus, the shock-absorbing instrument 30 is allowed to friction slide with respect to the shock-absorbing rope member 40 so as to absorb the impact energy. In addition, the amount of deflection of the net body 4 can become large as the shock-absorbing loop 63 enlarges, thereby improving the effectiveness of absorbing the impact energy.
Further, according to the present embodiment, the shock-absorbing turn-back portion 24 and or the net body intersecting portion 23 is inserted though the shock-absorbing loop 63 serving as the loop portion. In this sense, the net body turn-down portion 24 or the net body intersecting portion 23 can be linked to the shock-absorbing loop 63 by allowing the net body turn-down portion 24 or the net body intersecting portion 23 to be inserted thereinto, thereby obtaining a shock-absorbing device with a simple structure.
Further, as an effect of the present embodiment, the upper transverse rope member 11 serving as the linkage member can be inserted through the shock-absorbing loop 63, thereby allowing the shock-absorbing structure 48 to be easily attached to the linkage member.
An embodiment 5 of the present invention is shown in
Further, the end portions 40T, 40T protruding from the shock-absorbing instrument 30 become the extra length portions 44. In addition, in this case, the shock-absorbing rope member 40 and a pair of shock-absorbing instruments 30, 30 compose the shock-absorbing structure 48.
According to
And then, once the wire net 21 located on one of the left and right sides of the pole 3 in the center has been subjected to a force of impact, and a force stronger than a predetermined force has been applied to the shock-absorbing loop 63 by the net body turn-down portion 24, the extra length portions 44, 44 in opposite directions will friction slide with respect to the shock-absorbing instrument 30 so as to absorb the force of impact, and the shock-absorbing rope member 40 having a loop-like shape as a whole will become large as the extra length portions 44, 44 friction slide, thereby causing the wire net 21 to move to a side thereof which has been subjected to the force of impact. In this sense, the amount of deformation of the wire net 21 becomes large, thus absorbing the force of impact also.
Furthermore, according to the present embodiment, the shock-absorbing rope member 40 is inserted through a plurality of the mesh patterns of the net body turn-down portions 24 or the net body intersecting portions 23. The two end portions of the shock-absorbing rope member 40 are turned back in opposite directions, and the portions in which the two end portions 40T, 40T are thus turned back are fastened to the pin bolts 51, 51 serving as the linkage portions of the guard fence 1. Such end portions 40T, 40T in opposite directions are laid one on top of another, and the shock-absorbing instrument 30 is used to hold the portion in which the end portions 40T, 40T are thus laid one on top of another. Therefore, once an impact energy due to rockfall or the like has been applied to the net body 4, a tension force will be applied to the shock-absorbing rope member 40 inserted through a plurality of the mesh patterns of the net body turn-down portions 24 or the net body intersecting portions 23. Thus, the end portions 40T, 40T of the shock-absorbing rope member 40 are allowed to friction slide with respect to the shock-absorbing instrument 30 so as to absorb the impact energy, said shock-absorbing instrument 30 holding the portion in which the two end portions 40T, 40T are laid one on top of another. In addition, the amount of deflection of the net body 4 can become large as the shock-absorbing rope member 40 friction slides, thereby improving the effectiveness of absorbing the impact energy.
An embodiment 6 of the present invention is shown in
Further, short auxiliary rope members 82, 82 are linked to the upper and lower pin bolts 51, 51, respectively, in a manner such that the auxiliary rope member 82 is held by one of the grooves 35 of the shock-absorbing instrument 30. And, a stopper 83 fastened to the shock-absorbing instrument 30 is provided on an end portion of such auxiliary rope member 82. The extra length portion 44 is then held by the other groove 35 of the shock-absorbing instrument 30, thus allowing the shock-absorbing rope member 40 to be stretched on the rear side of the pole 3.
In addition, the shock-absorbing rope member 40 may also be fastened to an upper and a lower net body turn-down portions 24 or net body intersecting portions 23 while being wound around the upper and lower transverse rope members 11, 12, instead of the longitudinal rope member 52.
And then, once the wire net 21 has been subjected to a force of impact, and a force stronger than a predetermined force has been applied to the shock-absorbing rope member 40 by the net body turn-down portion 24, at least one of the upper and lower extra length portions 44, 44 will friction slide with respect to the shock-absorbing instruments 30, 30 so as to absorb the force of impact, and the shock-absorbing rope member 40 between the shock-absorbing instruments 30, 30 will stretch as the extra length portions 44, 44 friction slide, thereby allowing the wire net 21 to move away from the longitudinal rope member 52. In this sense, the amount of deformation of the wire net 21 becomes large, thus absorbing the force of impact also.
Furthermore, according to the present embodiment, the shock-absorbing rope member 40 is inserted through a plurality of the mesh patterns of the net body turn-down portions 24 or the net body intersecting portions 23. The pin bolts 51, 51 serving as the linkage portions of the guard fence 1 are respectively provided with the shock-absorbing instruments 30, 30 corresponding to the two end portions 40T, 40T of the shock-absorbing rope member 40. Such shock-absorbing instruments 30, 30 on both sides are used to hold the two end portions 40T, 40T of the shock-absorbing rope member 40, respectively. Therefore, once an impact energy due to rockfall or the like has been applied to the net body 4, a tension force will be applied to the shock-absorbing rope member 40 inserted through a plurality of the mesh patterns of the net body turn-down portions 24 or the net body intersecting portions 23. Thus, at least one of the end portions 40T, 40T of the shock-absorbing rope members 40, 40 is allowed to friction slide with respect to the shock-absorbing instruments 30, 30 holding the two end portions 40T, 40T, thereby absorbing the impact energy. In addition, the amount of deflection of the net body 4 can become large as the shock-absorbing rope member 40 friction slides, thereby improving the effectiveness of absorbing the impact energy.
Furthermore, as an effect of the present embodiment, two shock-absorbing instruments 30, 30 are used to hold one shock-absorbing rope member 40, thereby improving the effectiveness of shock absorbing.
An embodiment 7 of the present invention is shown in
Further, the shock-absorbing structure 48 is composed of a pair of the shock-absorbing rope members 40, 40, a pair of the shock-absorbing instruments 30, 30 and a pair of the loops 84, 84.
In addition, the longitudinal rope members 52, 52 provided on the poles 3, 3 may be used as a pair of the rope members distant from each other. And, pairs of the shackles 45, 45 can be provided on both longitudinal rope members 52, 52 in the form of multiple rows. In this way, pairs of the shock-absorbing rope members 40, 40 are then stretched between the poles 3, 3, and provided as transverse rope members and in the form of multiple rows between the upper and lower transverse rope members 11, 12.
And then, once the wire net 21 has been subjected to a force of impact, and a force trying to pull the loop 84 of the shock-absorbing rope member 40 toward the center has been applied by the net body turn-down portion 24, at least one of the upper and the lower extra length portions 44, 44 will friction slide with respect to the shock-absorbing instruments 30, 30 by moving outward, thereby absorbing the force of impact. In addition, the shock-absorbing rope member 40 between the shock-absorbing instruments 30, 30 will stretch as the extra length portions 44, 44 friction slide, thereby allowing the wire net 21 to move away from the upper and lower transverse rope members 11, 12. In this sense, the amount of deformation of the wire net 21 becomes large, thus absorbing the force of impact also.
Further, according to the present embodiment, the linkage member is a pair of linking rope members provided on the guard fence 1. Specifically, the upper and lower rope members 11, 12 serve as the pair of the linking rope members, and are so arranged that they are distant from each other. The turn-back portion 40K formed by turning back a front end portion of the shock-absorbing rope member 40 is movably fastened to the upper and lower transverse rope members 11, 12, respectively, said upper and lower transverse rope members 11, 12 being provided as a pair and serving as one and the other linking members. The net body turn-down portion 24 or the net body intersecting portion 23 is linked to the linking loop 84 formed on the front end portion, and the extra length portion 44 is provided on the other side of the shock-absorbing rope member 40. The extra length portions 44, 44 of one and the other shock-absorbing rope members 40, 40 are then laid one on top of another, and the shock-absorbing instrument 30 is used to hold the portion in which the extra length portions 44, 44 are thus laid one on top of another. Therefore, once an impact energy due to rockfall or the like has been applied to the net body, a tension force working in one direction will be applied to the linking loop 84 formed on the front end portion of the shock-absorbing rope member 40, said linking loop 84 being linked to a plurality of the net body turn-down portions 24 or the net body intersecting portions 23. Thus, a tension force trying to pull the extra length portion 44 in a direction opposite to the aforementioned one direction will be generated, thereby allowing the extra length portion 44 to friction slide with respect to the shock-absorbing instrument 30, and thus absorbing the impact energy. In addition, the amount of deflection of the net body 4 can become large as the shock-absorbing rope member 40 friction slides, thereby improving the effectiveness of absorbing the impact energy.
Furthermore, as an effect of the present embodiment, the linking loop 84 is provided on the front end portion of the shock-absorbing rope member 40, thereby making it easier to link the linking loop 84 to the net body turn-down portion 24 or the net body intersecting portion 23 through insertion.
An embodiment 8 of the present invention is shown in
Further, various types of linking structures can be employed as the linking structures for the net body intersecting portion 23 of the wire net 21.
However, the present invention is not limited to the aforementioned embodiments, and various modified embodiments are possible. For example, net bodies with various shapes can be employed as the net body. Further, although a pole having a circular cross portion is employed according to the embodiments, a pole having a rectangular cross portion can also be employed. Further, various detachable linking means other than the shackle can be employed for movably linking the net body to the upper edge and lower edge rope members, as long as they have a loop for inserting a rope member or the like therethrough. Further, although rope members made of steel are employed according to the embodiments, rope members made of other materials such as synthetic resin or the like can also be employed. Further, the number of the poles in the center can be two or more. Further, the stopper can actually be provided on the end portion of the shock-absorbing rope member even with the embodiments in which the stopper is not shown. Further, all the rope members employed in the present invention are flexible. Further, according to the embodiments, the upper and lower transverse rope members and the longitudinal rope member are employed as the linkage members. However, an upper and lower transverse rods made of a hard material and stretched between the upper portions or lower portions of the pole may also be employed as the linkage members, instead of the upper and lower transverse rope members. Also, a longitudinal rod made of a hard material and longitudinally provided on the pole may be employed as the linkage member, instead of the longitudinal rope member. Various members provided on the guard fence other than the net body can be used as the linkage members. Further, an auxiliary net made of a thin wire member and having smaller mesh patterns than those of the wire net can be superimposed on the wire net.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-269331 | Nov 2009 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2010/071065 | 11/25/2010 | WO | 00 | 1/20/2011 |
