JP3845062B2 - Fall bridge prevention device with displacement limiting function - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a falling bridge prevention device with a displacement limiting function for preventing the bridge girder or the like from falling from an abutment or a pier when a heavy load is applied while limiting the displacement of a bridge member such as a bridge girder constituting the bridge. Is.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an apparatus for preventing a bridge member such as a bridge girder from dropping, an apparatus disclosed in Patent Document 1 is known.
[0003]
[Patent Document 1]
Japanese Patent No. 3300284 (pages 3 to 4, FIGS. 1 to 7)
[0004]
The apparatus shown in this document includes a connecting member that connects bridge members such as a bridge girder and a cylinder through which the connecting member is inserted. The cylinder is attached to one bridge member so as to be movable in a direction parallel to the axial direction of the connecting member, and is biased in a direction away from the other bridge member by a spring. The end is fastened with a knock-off bolt.
[0005]
In this device, the relative displacement between the bridge members during normal use is absorbed by the axial movement of the tubular body and the connecting material accompanied by the expansion and contraction of the spring.
[0006]
On the other hand, for example, when a certain load or more is applied in a direction in which the bridge members are separated from each other due to an earthquake, as shown in FIG. 3 of the same document, a space between the bearing plate provided at the end of the cylinder and the bridge member is used. The cylinder moves to a position where the cushioning material (safety stopper) is sandwiched between the cylinders and the movement of the cylinder and the connecting material is restricted at that position. Further, when a larger load is applied due to a large earthquake, the knock-off bolt is broken by losing the load, the end of the connecting material moves in the cylinder, and the fixing washer provided at the end is a bearing plate. The buffer material is pressed in the compression direction via Seismic energy is absorbed by the compression deformation of the buffer material, and finally the end of the connecting material is locked to the bridge member side at a specific position. By this connecting material, the connecting state of the bridge members is maintained, and the bridge members are prevented from falling from the abutment or the pier.
[0007]
[Problems to be solved by the invention]
The apparatus disclosed in Patent Document 1 has the following problems to be solved.
[0008]
A) In this apparatus, when a certain tensile load is applied to the connecting material, the knock-off bolt that connects the connecting material and the cylinder is broken so that the connecting material can be displaced beyond the previous displacement limit position. However, in order to match the tensile load with the load sheared by the knock-off bolt, the number of bolts, the bolt size, the tap of the washer portion, and the like must be changed. For this purpose, a complicated design study is required, and the processing of each member is complicated.
[0009]
B) Since this apparatus is configured such that the cylinder moves integrally with the connecting member, another guide member for restricting the movement of the cylinder in the axial direction is required, and the structure is complicated and the parts There are many points, and there is a disadvantage that construction takes time. Further, since a relatively heavy cylinder is displaced integrally with the connecting material, it is difficult to expect a smooth movement of the connecting material, and it is necessary to improve the operation during normal use or emergency.
[0010]
An object of the present invention is to solve the above problems.
[0011]
[Means for Solving the Problems]
  As means for solving the above-mentioned problems, the present invention limits the relative displacement between the bridge members constituting the bridge within a specific allowable displacement range, and a load of a certain level or more acts in the direction in which both the component members are separated from each other. In the falling bridge prevention device with a displacement limiting function for restricting the relative displacement amount within a range in which the bridge member can be prevented from falling while allowing a relative displacement exceeding the allowable displacement range, the bridge members A connecting member that connects the connecting member, a cylinder that is fixed to at least one bridge member, and the connecting member is inserted through the connecting member, and an insertion member that is provided in the connecting member and has a shape that can be inserted into the cylinder.When,At the end of the cylinder that is closer to the other bridge memberProvided,Stopper for preventing movement of the insertion member in the insertion directionWhen,Apart from the end of the cylinder opposite the stopper,Whether the insertion memberDiameterDirection outwardProjecting from the outer peripheral surface of the cylinderTemporary stopperAnd withThe temporary stopper portion abuts against the end of the cylinder opposite to the stopper, so that the movement of the fitting member in the direction of fitting into the cylinder is restricted, and a load of a certain level or more in the fitting direction. In this case, the temporary stopper portion is broken and the fitting member is inserted into the cylindrical body up to a position where movement of the fitting member is prevented by the stopper.
[0012]
In this device, during normal use, the relative displacement between the bridge members is absorbed by the connecting member moving in the axial direction with respect to the cylinder fixed to the bridge member. Since the movement of the fitting member in the direction in which the fitting member is fitted into the cylinder is restricted when the temporary stopper portion on the outer periphery of the member contacts the end of the cylinder, the bridge member is controlled by the movement restriction. The relative displacement amount between them is limited.
[0013]
However, if a load exceeding a certain level is applied to the connecting member due to an earthquake or the like in a state where the temporary stopper portion is in contact with the end of the cylindrical body in this way, the temporary stopper portion is sheared and destroyed due to the load. The stopper portion is left behind, and only the inner fitting member is inserted into the cylinder and proceeds. This fitting member stops when it moves to a position where movement is prevented by the stopper at the end on the back side of the cylinder, and the connecting member is locked to the bridge member side at this position. The connection state of the bridge members is maintained by the connection member, and the bridge member is prevented from falling from the abutment or the pier.
[0014]
In this apparatus, since the displacement restriction is released by shearing of the temporary stopper portion protruding radially outward from the fitting member, for example, as disclosed in Patent Document 1, the displacement restriction is released by breaking the knock-off bolt. In comparison, it is easy to set the load when the displacement restriction is released. In other words, in the structure described in the document, the number of bolts, bolt size, tap of washer, etc. must be changed, which requires complicated design considerations, and the number of parts increases by the amount of bolts. While there is a drawback that the assembling work is complicated, in the apparatus according to the present invention, it is possible to determine the load when the displacement restriction is released simply by setting the cross-sectional area of the shearing portion of the temporary stopper part. In addition, there is an advantage that the structure is simple and easy to assemble.
[0015]
In particular, in the case where the temporary stopper portion is formed in a plate shape having a constant thickness, the displacement restriction release load (the load at which the temporary stopper portion is sheared) can be easily designed by setting the thickness.
[0016]
On the other hand, in the present invention, the cylinder is fixed to the bridge member side, and the fitting member is relatively displaced with respect to the cylinder, so that the movement of the cylinder is axially performed as described in the patent document. Therefore, another guide member for restricting to the above is unnecessary, and the structure becomes simpler and the labor of construction can be saved. In addition, since the cylinder does not move and only the connecting member and the fitting member move, the movement of the connecting member is smoother than that of the conventional apparatus that moves to the relatively heavy cylinder.
[0017]
In particular, the temporary stopper portion is formed over the entire circumference of the insertion member, and has a shape in which a plurality of through holes arranged intermittently in the circumferential direction are provided in the root portion connected to the outer periphery of the insertion member, A plurality of guide portions that can be inserted into the respective through holes extend from the end portion on the opposite side of the stopper from the end portion of the cylindrical body, and extend in the axial direction of the cylindrical body. If the moving direction of the temporary stopper portion and the fitting member connected thereto is restricted in the axial direction of the cylindrical body by insertion, the moving direction of the temporary stopper portion and the fitting member is reliably restricted with a simple structure. Moreover, the shear load of the temporary stopper portion (by setting the ratio between the circumferential length of the through hole and the circumferential length of the other portion (the portion where the temporary stopper portion is connected to the fitting member) ( Displacement limit is solved It is possible to more easily design a load) to be.
[0018]
Further, by projecting the temporary stopper portion radially outward from the insertion member as described above, the insertion member is interposed between the temporary stopper portion and the cylindrical body or bridge member and the temporary stopper portion. A spring member that urges the fitting member in a direction away from the stopper can be disposed around the cylindrical body, and the urging force of the spring member tensions the connecting member to some extent regardless of the displacement of the fitting member. It becomes possible to hold in the state.
[0019]
  In addition, the present invention limits the relative displacement between the bridge members constituting the bridge within a certain range, and absorbs the energy of the load when a load of a certain level or more acts in a direction in which both the component members are separated from each other. In the falling bridge prevention device with a displacement limiting function for preventing the bridge member from falling, a connecting member for connecting the bridge members to each other, and a cylindrical body that is fixed to at least one of the bridge members and into which the connecting member is inserted And a fitting member provided in the connecting member and having a shape that can be fitted into the cylinder.When,At the end of the cylinder that is closer to the other bridge memberProvided,Stopper for preventing movement of the insertion member in the insertion directionWhen,The other side of the cylinderEnd ofFromRadially inwardProtrudeTemporary stopperAnd an energy absorbing protrusion that protrudes inward from the inner peripheral surface of the cylindrical body at a position closer to the stopper than the temporary stopper.When the temporary stopper portion comes into contact with the insertion member, the movement of the insertion member in the direction in which the temporary stopper portion is inserted into the cylinder is restricted, and the temporary stopper is applied when a load of a certain level or more is applied in the insertion direction. Part breaksIn addition, the energy absorption protrusion is shear fractured.And it is comprised so that the said insertion member may be inserted in the said cylinder body to the position by which the movement prevention is carried out by the said stopper.
[0020]
Even in this configuration, since the displacement restriction is released by shearing of the temporary stopper portion protruding radially inward from the cylindrical body, for example, as disclosed in Patent Document 1, the displacement restriction is released by breaking the knock-off bolt. Compared to the above, it is easy to set the load when the displacement restriction is released. That is, it is possible to determine the load when the displacement restriction is released simply by setting the cross-sectional area of the shearing portion of the temporary stopper portion, and there is an advantage that the structure is simple and easy to assemble. .
[0021]
  On the other hand, in the present invention, the cylinder is fixed to the bridge member side, and the fitting member is relatively displaced with respect to the cylinder, so that the movement of the cylinder is axially performed as described in the patent document. Therefore, another guide member for restricting to the above is unnecessary, and the structure becomes simpler and the labor of construction can be saved. In addition, since the cylinder does not move and only the connecting member and the fitting member move, the movement of the connecting member is smoother than that of the conventional apparatus that moves to the relatively heavy cylinder.
  And since the said insertion member is inserted in the said cylinder, carrying out the shear destruction of the protrusion part for energy absorption, the said energy is effectively absorbed by the said shear with a simple structure.
[0022]
In the falling bridge preventing device with a displacement limiting function according to the present invention, an energy absorbing material that absorbs energy by applying resistance to the movement of the fitting member in the direction of fitting into the cylinder is provided in the cylinder. More preferable.
[0023]
According to this configuration, when the temporary stopper portion is sheared and the insertion member advances in the cylindrical body, the energy is effectively absorbed and the impact force is reduced by receiving resistance from the energy absorber.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS.
[0026]
FIG. 4A shows an application of the fall prevention device 20 with a displacement limiting function according to this embodiment to fall prevention of the bridge girder 14 adjacent to the abutment 10.
[0027]
In the figure, the end of the bridge beam 14 is simply supported on the upper surface of the abutment 10. Further, a protruding portion 10 a protrudes upward from the upper surface of the abutment 10 and is adjacent to the end portion 14 a of the bridge girder 14. The protruding portion 10 a and the end portion 14 a of the bridge girder 14 are connected via a cable (connecting member) 16.
[0028]
The cable 16 is respectively inserted into a horizontal insertion hole 10b provided in the protruding portion 10a and a horizontal insertion hole 14b provided in the bridge girder end portion 14a, and the protruding portion 10a side of the cable 16 is provided. Is fixed to the outer side surface (the left side surface in FIG. 1A) of the protruding portion 10a by the fixing device 18, while the end portion of the cable 16 on the bridge girder 14 side is the structure of the falling bridge prevention device 20. Is attached to the inner side surface of the bridge girder end portion 14a (the right side surface in FIG. 5A). By the action of the falling bridge prevention device 20, the relative displacement of the end girder 14 with respect to the abutment 10 during normal use is limited to a specific allowable displacement range, while the abutment 10 and the bridge girder 14 are separated from each other by an earthquake or the like. The bridge girder 14 is prevented from falling from the abutment 10 while allowing a relative displacement exceeding the allowable displacement range when a certain load or more is applied to the bridge.
[0029]
In addition, the falling bridge prevention apparatus 20 concerning this invention may be provided in the abutment 10 side of Fig.4 (a), and may be provided in both the abutment 10 and the bridge girder 14. FIG. Further, as shown in FIG. 4B, the bridge girder 14 is prevented from falling from the pier 12 by connecting the ends 14a of the bridge girder 14 adjacent to each other on the pier 12 with the same structure as described above. Is also possible. However, the following description is given about an example in which the falling bridge prevention device 20 is used in the mode shown in FIG.
[0030]
A specific structure of the falling bridge prevention device 20 is shown in FIGS. In addition to the cable 16, the falling bridge prevention device 20 includes a cylindrical body 24 fixed to the bridge girder end portion 14 a and a ring 30 fixed to the bridge girder side end portion of the cable 16.
[0031]
The cylindrical body 24 is formed in a cylindrical shape extending in the horizontal direction in the illustrated example, and an end portion of the cable 16 can be inserted into the cylindrical body 24.
[0032]
A supporting pressure plate (stopper) 22 surrounding the cable 16 is fixed to one end portion of the cylindrical body 24 (the end portion on the side close to the protruding portion 10a of the abutment 10; the left end portion in FIGS. 1 and 3). The bearing plate 22 is attached to the bridge girder end portion 14a via a cushioning material 40 (see FIG. 3) made of rubber or the like. The other end of the cylindrical body 24 opens in a direction away from the abutment projecting portion 10a (rightward in FIGS. 1 and 3), and a plurality of locations (4 in the example shown in FIG. 2) are arranged in the circumferential direction. A rod-shaped guide portion 26 is further extended along the axial direction of the cylindrical body 24 from the point).
[0033]
In FIG. 2, reference numeral 23 denotes a bolt insertion hole provided in the bearing plate 22 in order to fix the bearing plate 22 to the bridge girder side.
[0034]
The ring 30 integrally includes a disc-shaped ring main body 32 and a thin plate-like temporary stopper plate 34 projecting radially outward from the outer peripheral surface of the ring main body 32 over the entire circumference.
[0035]
The ring main body 32 has a donut plate shape through which the cable 16 passes through the center portion thereof, and has an outer diameter that can be fitted into the cylindrical body 24 with almost no gap. Is comprised.
[0036]
The temporary stopper plate 34 is sufficiently thinner than the ring body 32 and has an outer diameter that protrudes radially outward from the outer peripheral surface of the cylindrical body 24. Further, in the base portion where the temporary stopper plate 34 is connected to the ring main body 32, through holes 36 are formed at positions corresponding to the guide portions 26 (a plurality of positions arranged intermittently in the circumferential direction). When the guide portions 26 are inserted into the through holes 36, the ring main body 32 is guided in the longitudinal direction (the axial direction of the cylinder 24 and the cable 16) by the guide portions 26, that is, the ring main body. 32 moving directions are regulated in the longitudinal direction.
[0037]
A male screw 17 is provided at the end of the cable 16, and a nut 29 having a smaller diameter than the ring main body 32 is screwed around the male screw 17, and the ring main body 32 from the cable 16 to the tip end side by the nut 29. Is being secured. On the other hand, a spring seat plate 28 projects from an appropriate position on the outer peripheral surface of the cylindrical body 24, and a compression coil spring 38 is compressed between the spring seat plate 28 and the outer peripheral portion of the temporary stopper plate 34. Intervened in a state. The ring 30 is pressed against the nut 29 by the elastic force of the compression coil spring 38 so that the slack of the cable 16 is suppressed.
[0038]
Here, the nut 29 and the ring 30 are attached to the cable 16 with the bridge girder 14 being in a normal relative position with respect to the abutment 10 as shown in FIG. 30 is set so as to be positioned substantially in the middle of the guide portion 26.
[0039]
The cylindrical body 24 is filled with a buffer material (energy absorbing material) 27 for giving a movement resistance to the ring main body 32 fitted in the cylindrical body 24. The buffer material 27 may be an elastic body such as rubber or a viscoelastic body, or may be a fluid with high viscosity. In the illustrated example, a fluid is used for the cushioning material 27, and the cushioning material 27 is discharged to the outside of the cylindrical body 24 from a not-shown hole as the ring body 32 advances into the cylindrical body 24. (See FIGS. 3A to 3C).
[0040]
Next, the operation of the falling bridge prevention device 20 will be described with reference to the graph of FIG. Note that the graph in the figure shows the relationship between the load P acting on the cable 16 and its displacement δ.
[0041]
First, when the protruding portion 10a and the bridge girder 14 of the abutment 10 shown in FIG. 4A are slightly displaced in the horizontal direction during normal use, the displacement is the movable stroke of the ring 30 (corresponding to the length of the guide portion 26). While within the range, the displacement is absorbed by the relative displacement between the ring 30 and the cylindrical body 24 accompanied by expansion and contraction of the compression coil spring 38, and a large load does not act on the cable 16 and the ring 30.
[0042]
However, when the projecting portion 10a and the bridge girder end portion 14a are separated from each other by a certain distance and the temporary stopper portion 32 comes into contact with the end surface of the cylindrical body 24 as shown in FIG. The cylinder 24 cannot be displaced relative to the abutment 10 side (left side in FIG. 3A). That is, the relative displacement of the bridge girder 14 with respect to the abutment 10 is limited at this position, and the relative displacement is kept within a certain range.
[0043]
If the bridge girder 14 is further displaced in the direction away from the abutment 10 from this position due to, for example, an earthquake, the displacement is only absorbed by the elastic deformation of the buffer material 40, and the cable 16 and the ring 30 are accompanied by the displacement. The load acting on the rises rapidly. When a large earthquake occurs until the load reaches a specific load (point A in FIG. 5), the temporary stopper plate 34 is sheared from the ring body 32 by losing the load, and the temporary stopper plate 34 is moved. Only the ring main body 32 is inserted into the cylindrical body 24 so as to remain on the distal end side of the cylindrical body 24. The load acting on the cable 16 and the ring main body 32 at the time of shearing sharply decreases (point B in FIG. 5).
[0044]
Thereafter, as the relative displacement of the bridge girder 14 with respect to the abutment 10 increases, the ring body 32 approaches the stopper 22 while being deeply inserted into the cylindrical body 24 (FIG. 3B). Since the buffer material 27 gives a movement resistance to the cable 16, the energy applied to the cable 16 and the ring body 32 is effectively absorbed, and a buffer effect is exhibited (in the example shown in the figure, the buffer material 27 is advanced with the progress of the ring body 32). Is gradually discharged from the cylinder 24).
[0045]
Thereafter, when the ring main body 32 comes into contact with the bearing plate 22 (FIG. 3C), the ring main body 32 can no longer be substantially displaced relative to the bridge girder 14, and the abutment 10 and the end girder 14 by the cable 16 are prevented. Is maintained in the connected state to prevent the end beam 14 from dropping from the abutment 10.
[0046]
When the buffer material 27 is a solid material such as rubber, the position sandwiched between the pressure plate 22 and the ring body 32 in a state where the buffer material 27 is contracted and deformed to the limit is the ring body 32. This is the final locking position.
[0047]
In the apparatus described above, the displacement restriction is released by shearing at the base portion of the temporary stopper plate 34 formed integrally with the ring main body 32 that is the fitting member. Therefore, for example, as shown in Patent Document 1, the knock-off bolt Compared to a structure in which the displacement restriction is released by breakage, it is easier to set the load when the displacement restriction is released. Specifically, by setting the thickness of the temporary stopper plate 34 and setting the size of the through hole 36 (in other words, setting the cross-sectional area of the root portion), the load when the displacement restriction is released can be easily achieved. In addition, there is an advantage that it can be determined appropriately, and the number of parts is small, the structure is simple, and the assembly is easy.
[0048]
In particular, when the temporary stopper portion is formed as a temporary stopper plate 34 having a certain thickness as shown in the figure, the displacement limit release load (the load at which the temporary stopper portion is sheared) can be easily set by setting the thickness. There are advantages that can be designed.
[0049]
Further, in the above apparatus, the cylindrical body 24 is fixed to the bridge girder 14 side, and the ring main body 32 is relatively displaced together with the cable 16 in the axial direction with respect to the cylindrical body 24. Therefore, the structure is simpler. In addition, the weight of the movable part is small, and the movement of the cable 16 can be made smoother.
[0050]
In particular, as shown in the figure, in addition to the cylindrical body 24, a plurality of guide portions 26 are extended forward from the cylindrical body 24, and the guide portions 26 are inserted into the through holes 36 on the temporary stopper plate 34 side. Thus, the moving direction of the ring 30 and the cable 16 can be reliably restricted in the axial direction of the cylindrical body with a simple configuration, and the circumferential length of the through-hole 36 and other portions (temporary stopper) By setting the ratio to the circumferential length of the portion where the plate 34 is connected to the fitting member), it becomes possible to more easily design the shear load of the temporary stopper plate 34 (load at which the displacement restriction is released).
[0051]
Further, by projecting the temporary stopper plate 34 radially outward from the ring body 32 as described above, the temporary stopper plate 34 and the spring seat plate 28 (for example, the bearing plate 22 or the bridge girder 14 side) are also provided. The compression coil spring 38 can be interposed between the cable 16 and the cable 16, and the elastic force of the cable 16 makes it possible to keep the cable 16 tensioned to some extent regardless of the displacement of the ring 30. ing.
[0052]
In the present invention, there is no limitation on the means for fixing the fitting member to the connecting member. For example, as shown in FIG. 6 as the second embodiment, the nut 29 shown in FIG. The temporary stopper plate 34 may be protruded radially outward from the outer peripheral surface 29. Thereby, the number of parts is further reduced.
[0053]
Further, the temporary stopper portion according to the present invention is not limited to the one formed over the entire circumference like the temporary stopper plate 34 shown in the drawing, for example, even if a plurality of protrusions are projected radially from the fitting member, It is possible to obtain the action of releasing the displacement restriction by the displacement restriction and the shearing of the temporary stopper portion.
[0054]
A third embodiment of the present invention will be described with reference to FIGS. In the figure, the basic structure of the cable 16, the bearing plate 22, the buffer material 40, and the cylindrical body 24 is the same as that shown in FIG.
[0055]
In this embodiment, a nut 29 screwed to the male screw portion 17 of the cable 16 also serves as a fitting member, as in the case of the second embodiment. Instead of projecting the stopper portion 34, ring-shaped ridges 25 extending over the entire circumference are projected inward at a plurality of positions aligned in the axial direction on the inner circumferential surface of the cylinder body 24, The relative displacement of the nut 29 and the cable 16 with respect to the cylinder 24 during normal use is limited at the position where the nut 29 abuts on the protrusion 25a (FIG. 7A) on the most distal end side of the cylinder. .
[0056]
In this structure, when a large tensile load of a certain level or more is applied to the cable 16 due to an earthquake or the like from the position shown in FIG. 7A, the most advanced ridge 25a is sheared against the tensile load, and the nut 29 is correspondingly cut. Enters the inside of the cylinder 24. Thereafter, the nut 29 is inserted deeply into the cylindrical body 24 while sequentially shearing the protrusions 25 arranged in the axial direction, and the energy applied to the nut 29 and the cable 16 is absorbed each time the shearing is performed, and the buffering effect is obtained. Is exerted ((b) in the figure). Then, the nut 29 and the cable 16 are locked at a position where the nut 29 comes into contact with the bearing plate 22 to prevent the falling bridge (FIG. 3C).
[0057]
In this device, since the displacement restriction is released by the shearing of the protrusion 25a provided on the inner surface of the cylindrical body 24, the thickness of the protrusion 25a is the same as the device shown in the first embodiment. By setting, it is possible to easily and appropriately determine the load when the displacement restriction is released, and there are advantages that the number of parts is small, the structure is simple, and the assembly is easy.
[0058]
Further, in the above apparatus, the cylindrical body 24 is fixed to the bridge girder 14 side, and the ring main body 32 is relatively displaced together with the cable 16 in the axial direction with respect to the cylindrical body 24. Therefore, the structure is simpler. In addition, the weight of the movable part is small, and the movement of the cable 16 can be made smoother.
[0059]
Furthermore, in this embodiment, the nut 29 is inserted into the cylinder 24 while sequentially shearing the ridges 25 formed on the inner surface of the cylinder 24, so that the nut 29 reaches the support plate 22. In the meantime, the energy can be absorbed effectively, and a remarkable buffering effect can be obtained.
[0060]
The energy absorbing ridges 25 are not necessarily formed over the entire circumference, and may be scattered, for example, at a plurality of positions aligned in the circumferential direction, or spiral in the axial direction of the cylindrical body 24. The shape which progresses in a shape may be sufficient.
[0061]
Further, the displacement limiting protrusion 25a is not necessarily formed over the entire circumference, and may be a protrusion provided intermittently in the circumferential direction.
[0062]
Also in the third embodiment, for example, a compression coil spring is loaded inside the cylindrical body 24 and an outward biasing force (a biasing force in a direction away from the other bridge member) is applied to the nut 29 and the cable 16. You may make it provide.
[0063]
【The invention's effect】
As described above, according to the present invention, it is possible to determine the load when the displacement restriction is released only by setting the cross-sectional area of the shearing portion of the temporary stopper portion, and the structure is simple and the assembly is also possible. There is an effect that it is easy. In addition, the cylinder is fixed to the bridge member side, so there is no need for a means for guiding it, and the structure is simplified to save the labor of construction and move to a relatively heavy cylinder. As compared with the conventional device, there is an effect that the movement of the connecting material can be made smoother.
[Brief description of the drawings]
FIG. 1 is a cross-sectional front view of a falling bridge prevention device with a displacement limiting function according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIGS. 3A to 3C are cross-sectional front views showing the operation of the falling bridge prevention device.
4A and 4B are partial cross-sectional front views showing examples of installation modes of the fallen bridge prevention device. FIG.
FIG. 5 is a graph showing a relationship between a load acting on a cable and a displacement in the fallen bridge prevention device.
FIG. 6 is a cross-sectional front view of a falling bridge preventing device with a displacement limiting function according to a second embodiment of the present invention.
FIG. 7 is a cross-sectional front view of a falling bridge prevention device with a displacement limiting function according to a third embodiment of the present invention.
[Explanation of symbols]
10 Abutment (bridge member)
14 Bridge girder (bridge member)
16 Cable (connection member)
17 Male thread
18 Fixing device
20 Fall bridge prevention device
22 Supporting plate (stopper)
23 Bolt insertion hole
24 cylinder
25 Projection (energy absorber)
25a ridge (temporary stopper)
26 Guide
27 Buffer material (energy absorbing material)
28 Spring seat plate
29 Nut (insertion member)
30 rings
32 Ring body (insertion member)
34 Temporary stopper plate
36 Through hole
38 Compression coil spring
40 cushioning material

Claims (6)

The relative displacement between the bridge members that make up the bridge is limited within a specific allowable displacement range, and relative displacement exceeding the allowable displacement range is allowed when a load of a certain level or more is applied in the direction in which both components are separated from each other. However, in the falling bridge prevention device with a displacement limiting function for restricting the relative displacement within a range in which the bridge member can be prevented from falling, the connecting member for connecting the bridge members to each other, and fixed to at least one of the bridge members A cylindrical body into which the coupling member is inserted, an insertion member provided in the coupling member and having a shape that can be fitted into the cylindrical body, and a bridge member at the other end of the cylindrical body. provided at an end portion of the near side, a stopper for preventing movement to its insertion direction of the insert member, spaced from the opposite end of the tubular body and the stopper, the insert member or al radially outward to the Tube And a temporary stopper portion also protrudes from the outer peripheral surface of the movement of the insert member in the direction to be fitted to the cylinder body by the temporary stopper portion abuts on an end opposite the tubular member and the stopper The temporary stopper portion is broken when the load is restricted and a certain load or more is applied in the insertion direction, and the insertion member is inserted into the cylinder to a position where movement of the insertion member is prevented by the stopper. A falling bridge prevention device with a displacement limiting function.   The falling bridge preventing device with a displacement limiting function according to claim 1, wherein the temporary stopper portion is formed in a plate shape having a certain thickness.   3. The falling bridge preventing device with a displacement limiting function according to claim 1 or 2, wherein the temporary stopper portion is formed over the entire circumference of the fitting member and intermittently circumferentially at a root portion connected to the outer circumference portion of the fitting member. A plurality of guide portions having shapes that can be inserted into the respective through holes from the end portion on the opposite side of the stopper among the end portions of the cylindrical body. A displacement limiting function characterized in that the movement direction of the temporary stopper portion and the fitting member connected thereto is restricted in the axial direction of the cylindrical body by extending along the axial direction of the cylindrical body, and by inserting the guide portion. Attached bridge prevention device.   The fall prevention device with a displacement limiting function according to any one of claims 1 to 3, wherein the fitting member is interposed between the cylindrical body or a bridge member and the temporary stopper portion around the cylindrical body. A falling bridge preventing device with a displacement limiting function, characterized in that a spring member for biasing the fitting member in a direction away from the stopper is provided. The relative displacement between the bridge members that make up the bridge is limited within a certain range, and when a load of more than a certain level is applied in the direction in which both component members are separated from each other, the bridge member falls while absorbing the energy of the load. In the falling bridge prevention device with a displacement limiting function for preventing the above, a connecting member that connects the bridge members, a cylinder that is fixed to at least one of the bridge members, and through which the connecting member is inserted, and the connecting member provided, the insert member having a fitting shape capable of the tubular body, provided at an end portion of the side close to the bridge member of the counterpart of the end portion of the cylindrical body, moving to its insertion direction of the insert member a stopper to prevent a temporary stopper portion projecting radially inward from the other end of said tubular body, inwardly at a position closer to the stopper than the temporary stopper portion from the inner peripheral surface of the cylindrical body And a energy absorbing protrusions and out, the temporary stopper movement of insert member in the direction to be fitted to the cylinder body is restricted by contact with the insert member, and, over a certain to the insertion direction The temporary stopper portion is broken when the load is applied, and the energy absorbing protruding portion is sheared and broken so that the insertion member is inserted into the cylinder to a position where movement is prevented by the stopper. A falling bridge prevention device with a displacement limiting function.   6. The apparatus for preventing falling bridges with a displacement limiting function according to any one of claims 1 to 5, wherein energy absorption is performed by providing resistance to movement of a fitting member in a direction in which the cylinder is fitted into the cylinder. A falling bridge prevention device with a displacement limiting function, characterized in that a material is provided.

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