JP2004244815A - Bridge falling preventive device with displacement restricting function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily set a load for releasing restriction of displacement; to simplify a structure; to facilitate installation work; and to further smooth the movement of a connecting material. <P>SOLUTION: A connecting member 16 for connecting mutual bridge members is inserted into a cylindrical body 24, and a fitting member 32 fittable in this cylindrical body 24 is arranged in a cable end part. A temporary stopper part 34 is projected outward in the radial direction from the fitting member 32, and the displacement of the bridge members is restricted by abutment of this temporary stopper part 34 and an end part of the cylindrical body 24. When the load of a specific value or more acts in an abutting state, the temporary stopper part 34 ruptures, and the fitting member 32 is fitted in the cylindrical body 24, and is locked by a stopper 22, and thereby prevents the bridge falling. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for preventing falling of a bridge with a displacement limiting function for preventing displacement of a bridge member such as a bridge girder constituting a bridge and preventing the bridge girder or the like from dropping from an abutment or a pier when a large load is applied, while limiting displacement of a bridge member such as a bridge girder constituting the bridge. Things.
[0002]
[Prior art]
BACKGROUND ART Conventionally, as a device for preventing a bridge member such as a bridge girder from falling, for example, a device disclosed in Patent Document 1 is known.
[0003]
[Patent Document 1]
Japanese Patent No. 3300284 (pages 3 and 4, FIGS. 1 to 7)
[0004]
The device disclosed in this document includes a connecting member for connecting bridge members such as a bridge girder, and a tubular body through which the connecting member is inserted. The tubular body 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 urged by a spring in a direction away from the other bridge member. 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 member accompanying the expansion and contraction of the spring.
[0006]
On the other hand, when a load equal to or more than a certain value acts in a direction in which the bridge members separate from each other due to an earthquake, for example, as shown in FIG. The cylinder moves to a position where a cushioning material (safety stopper) is sandwiched between the cylinders, and the movement of the cylinder and the connecting member is restricted at that position. Further, when a larger load is applied by a large earthquake, the knock-off bolt is broken by losing the load, the end of the connecting member moves in the cylinder, and the fixing washer provided at the same end is used as a support plate. And presses the cushioning material in the compression direction. Seismic energy is absorbed by the compressive deformation of the cushioning material, and the end of the connecting member is finally locked to the bridge member side at a specific position. With this connecting member, the connected state of the bridge members is maintained, and the bridge members are prevented from dropping from the abutment or the pier.
[0007]
[Problems to be solved by the invention]
The device disclosed in Patent Document 1 has the following problems to be solved.
[0008]
A) In the same device, when a constant tensile load is applied to the connecting member, the knock-off bolt connecting the connecting member and the cylinder is broken so that the connecting member can be displaced beyond the displacement limit position up to then. However, in order to match the tensile load with the load sheared by the knock-off bolt, it is necessary to change the number of bolts, the bolt size, the tap of the washer, and the like. For that purpose, a complicated design study is required, and there is a disadvantage that processing of each member becomes complicated.
[0009]
B) Since the device has a structure in which the cylinder moves integrally with the connecting member, another guide member for regulating the movement of the cylinder in the axial direction is necessary, and the structure is complicated and the parts are complicated. There are many points, and there is an inconvenience requiring time and labor for construction. Further, since a relatively heavy cylinder is also displaced integrally with the connecting member, it is difficult to expect a smooth movement of the connecting member, and it is necessary to improve operation during normal use and emergency.
[0010]
An object of the present invention is to solve the above problems.
[0011]
[Means for Solving the Problems]
As a means for solving the above-mentioned problems, the present invention restricts the relative displacement between bridge members constituting a bridge within a specific allowable displacement range, and applies a load equal to or more than a certain value in a direction in which both members are separated from each other. In the device for preventing falling of a bridge with a displacement limiting function for restricting the relative displacement within a range in which the bridge member can be prevented from dropping while allowing a relative displacement exceeding the allowable displacement range, A connecting member that is fixed to at least one bridge member, and a tubular body into which the connecting member is inserted, and a fitting member provided on the connecting member and having a shape that can be fitted into the tubular body. A stopper for preventing movement of the fitting member in the fitting direction is provided at an end portion of the end portion of the cylindrical body closer to the other bridge member, and a radial direction is provided from the fitting member in the radial direction. The temporary stopper portion protrudes to the side, and the temporary stopper portion abuts on the end of the cylindrical body opposite to the stopper, whereby the movement of the fitting member in the direction of fitting into the cylindrical body is regulated, and When a predetermined load or more acts on the fitting direction, the temporary stopper portion is broken, and the fitting member is fitted into the cylinder to a position where the fitting member is prevented from moving.
[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 tubular body fixed to the bridge member, but the fitting provided on the connecting member is Since the temporary stopper portion on the outer periphery of the member abuts on the end of the tubular body, the movement of the fitted member in the direction in which the fitted member is fitted into the tubular body is regulated. The relative displacement between them is limited.
[0013]
However, if a load more than a certain amount acts on the connecting member due to an earthquake or the like while the temporary stopper portion is in contact with the end of the cylindrical body, the temporary stopper portion is sheared and destroyed by losing the load, and the temporary stopper is damaged. With the stopper portion left, only the inner fitting member is fitted into the cylinder and proceeds. The fitting member stops when it moves to a position where movement of the fitting member is stopped by the stopper at the end on the back side of the cylindrical body. At this position, the connecting member is locked to the bridge member side. The connection state of the bridge members is maintained by the connection members, and the bridge members are prevented from dropping from the abutment or the pier.
[0014]
In this device, since the displacement limit is released by shearing of the temporary stopper projecting radially outward from the fitting member, for example, as shown in Patent Document 1, the displacement limit is released by breaking the knock-off bolt. In comparison, it is easier to set the load when the displacement restriction is released. In other words, in the structure described in the document, the number of bolts, the bolt size, the tap of the washer, and the like must be changed, which requires a complicated design study, and the number of parts increases by the amount of the bolts. While the assembling work also has the disadvantage of being complicated, the apparatus according to the present invention can determine the load when the displacement limit is released only by setting the cross-sectional area of the shearing portion of the temporary stopper. In addition, there is an advantage that the structure is simple and the assembling is easy.
[0015]
In particular, in the case where the temporary stopper portion is formed in a plate shape having a certain thickness, the displacement limit 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 tubular body is fixed to the bridge member side, and the fitting member is relatively displaced with respect to this tubular body. A separate guide member is not required to restrict the pressure, and the structure is made simpler and the work of construction can be saved. Moreover, since only the connecting member and the fitting member are moved without moving the cylinder, the movement of the connecting member is smoother than in the conventional device which moves to a relatively heavy cylinder.
[0017]
In particular, the temporary stopper portion is formed over the entire periphery of the fitting member, and has a shape in which a plurality of through holes are intermittently arranged in a circumferential direction at a base portion connected to an outer peripheral portion of the fitting member. From the end of the cylindrical body opposite to the stopper, a plurality of guide portions having a shape insertable into the respective through holes extend along the axial direction of the cylindrical body. If the moving direction of the temporary stopper portion and the fitting member connected thereto is restricted by the insertion in the axial direction of the cylindrical body, the moving direction of the temporary stopper portion and the fitting member is reliably restricted with a simple structure. In addition, 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), the shear load ( Displacement limit solved It is possible to more easily design a load) to be.
[0018]
Further, by projecting the temporary stopper portion radially outward from the fitting member as described above, the temporary stopper portion is interposed between the temporary body and the tubular member or the bridge member and the temporary stopper portion, and the fitting member is moved. A spring member for urging the insertion member in a direction away from the stopper can be provided around the cylindrical body, and the urging force of the spring member stretches the connection member to some extent regardless of the displacement of the insertion member. It is possible to maintain the state.
[0019]
Further, the present invention restricts the relative displacement between the bridge members constituting the bridge within a certain range, and absorbs the energy of the load when a certain load or more is applied in a direction in which both the members are separated from each other. In a fall prevention device with a displacement limiting function for preventing a bridge member from falling, a connecting member for connecting the bridge members to each other, and a tubular body fixed to at least one of the bridge members and through which the connecting member is inserted. And a fitting member provided on the connecting member, the fitting member having a shape capable of being fitted into the cylindrical body. The fitting of the fitting member is performed at an end of the cylindrical body closer to a bridge member on the other side. A stopper for preventing movement in the direction is provided, and at the other end, a temporary stopper portion projects radially inward, and the temporary stopper portion comes into contact with the fitting member to enter the cylindrical body. The movement of the insertion member in the insertion direction is regulated, and when a load equal to or more than a certain amount is applied in the insertion direction, the temporary stopper portion is broken to a position where the insertion member is prevented from moving by the stopper. It is configured to be fitted into the cylinder.
[0020]
Also in this configuration, since the displacement limitation is released by shearing of the temporary stopper portion projecting radially inward from the cylinder, the displacement limitation is released by breaking of the knock-off bolt as shown in Patent Document 1, for example. It is easier to set a load when the displacement limitation is released than in the case of. That is, it is possible to determine the load when the displacement limitation is released only by setting the cross-sectional area of the shear portion of the temporary stopper portion, and there is an advantage that the structure is simple and the assembly is easy. .
[0021]
On the other hand, in the present invention, the tubular body is fixed to the bridge member side, and the fitting member is relatively displaced with respect to this tubular body. A separate guide member is not required to restrict the pressure, and the structure is made simpler and the work of construction can be saved. Moreover, since only the connecting member and the fitting member are moved without moving the cylinder, the movement of the connecting member is smoother than in the conventional device which moves to a relatively heavy cylinder.
[0022]
In the bridge-preventing device with a displacement limiting function according to the present invention, an energy absorbing material that absorbs energy by providing resistance to movement of the insertion member in a direction in which the insertion member is inserted into the cylinder may be provided. Is more preferable.
[0023]
According to this configuration, when the temporary stopper portion is sheared and the fitting member advances in the cylindrical body, the energy is effectively absorbed by receiving resistance from the energy absorber, and the impact force is reduced.
[0024]
For example, an energy absorbing projection that projects inward at a position closer to the stopper than the temporary stopper is formed on the inner peripheral surface of the cylindrical body, and the fitting member is formed while shearing and breaking the energy absorbing projection. In a configuration configured to be fitted into the cylinder, the energy is effectively absorbed by the shearing with a simple configuration.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS.
[0026]
FIG. 4A shows an example in which the fall prevention device 20 with the displacement limiting function according to the present embodiment is applied to the fall prevention of the bridge girder 14 adjacent to the abutment 10.
[0027]
In the figure, the end of the bridge girder 14 is simply supported on the upper surface of the abutment 10. Further, a projecting portion 10 a projects upward from the upper surface of the abutment 10 and is adjacent to an end 14 a of the bridge girder 14. The projecting portion 10a and the end 14a of the bridge girder 14 are connected via a cable (connection member) 16.
[0028]
The cable 16 is 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, respectively. Of the cable 16 is fixed to the outer surface (the left side in FIG. 3A) of the projecting portion 10a by the fixing device 18, while the end of the cable 16 on the bridge girder 14 side has the structure of the fall prevention device 20. Thus, the bridge girder is attached to the inner side surface (the right side surface in FIG. 7A) of the end portion 14a. In the normal use, the relative displacement of the end girder 14 with respect to the abutment 10 is limited to a specific allowable displacement range by the action of the fall prevention device 20, while the abutment 10 and the girder 14 are separated from each other due to an earthquake or the like. The bridge girder 14 is prevented from dropping from the abutment 10 while allowing a relative displacement exceeding the allowable displacement range when a load equal to or more than a certain value acts on the bridge abutment.
[0029]
The bridge drop prevention device 20 according to the present invention may be provided on the abutment 10 side in FIG. 4A, or may be provided on both the abutment 10 and the bridge girder 14. Further, as shown in FIG. 2B, by connecting the ends 14a of the bridge girders 14 adjacent to each other on the pier 12 with the same structure as described above, it is possible to prevent the bridge girders 14 from dropping from the pier 12. Is also possible. However, the following description is made with respect to an example in which the bridge prevention device 20 is used in the mode shown in FIG.
[0030]
1 to 3 show a specific structure of the bridge falling prevention device 20. The fall prevention device 20 includes, in addition to the cable 16, a tubular body 24 fixed to the bridge girder end 14 a and a ring 30 fixed to the bridge girder end 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 the end of the cable 16 can be inserted therein.
[0032]
A support plate (stopper) 22 surrounding the cable 16 is fixed to one end of the tubular body 24 (an end near the protruding portion 10a of the abutment 10; a left end in FIGS. 1 and 3). The support plate 22 is attached to the bridge girder end 14a via a cushioning member 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 (to the right in FIGS. 1 and 3), and has a plurality of locations (4 in the example shown in FIG. A rod-shaped guide portion 26 extends further along the axial direction of the cylindrical body 24 from the position (point).
[0033]
In FIG. 2, reference numeral 23 denotes a bolt insertion hole provided in the support plate 22 for fixing the support plate 22 to the bridge girder.
[0034]
The ring 30 integrally includes a disk-shaped ring main body 32 and a thin-plate-shaped 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 penetrates a central portion thereof, and has an outer diameter capable of being fitted into the cylindrical body 24 with almost no gap. Is composed.
[0036]
The temporary stopper plate 34 is sufficiently thinner than the ring main body 32 and has an outer diameter enough to protrude radially outward from the outer peripheral surface of the cylindrical body 24. Further, in a 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 respective guide portions 26 (a plurality of positions intermittently arranged in the circumferential direction). Each of the guide portions 26 is inserted into the through-hole 36, so that the guide portions 26 guide the ring body 32 in the longitudinal direction (the axial direction of the cylindrical body 24 and the cable 16). The movement direction of 32 is regulated in the longitudinal direction.
[0037]
A male screw 17 is provided at an 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. The nut 29 allows the ring main body 32 to move from the cable 16 to the distal end side. Has been retained. On the other hand, a spring seat plate 28 is protruded at 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. Intervening in the state. Then, the ring 30 is pressed against the nut 29 by the resilient force of the compression coil spring 38, and the slack of the cable 16 is suppressed.
[0038]
Here, the mounting position of the nut 29 and the ring 30 in the cable 16 is such that the bridge girder 14 is at a regular relative position with respect to the abutment 10 as shown in FIG. 30 is set so as to be located substantially in the middle of the guide portion 26.
[0039]
The inside of the cylindrical body 24 is filled with a cushioning material (energy absorbing material) 27 for giving a movement resistance to the ring main body 32 fitted in the cylindrical body 24. The cushioning material 27 may be an elastic body such as rubber or a viscoelastic body, or may be a high-viscosity fluid. In the illustrated example, a fluid is used as the cushioning material 27, and the cushioning material 27 is discharged from the unillustrated hole to the outside of the cylinder 24 as the ring main body 32 advances into the cylinder 24. (See FIGS. 3A to 3C).
[0040]
Next, the operation of the fall prevention device 20 will be described with reference to the graph of FIG. In addition, the graph in the same figure shows the relationship between the load P acting on the cable 16 and its displacement δ.
[0041]
First, when the projecting portion 10a of the abutment 10 and the bridge girder 14 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 staying inside, the displacement is absorbed by the relative displacement between the ring 30 and the cylindrical body 24 accompanying the expansion and contraction of the compression coil spring 38, and no large load acts on the cable 16 and the ring 30.
[0042]
However, when the protruding portion 10a and the bridge girder end 14a are separated from each other by a certain distance or more and the temporary stopper portion 32 comes into contact with the end surface of the cylindrical body 24 as shown in FIG. It becomes impossible to displace relative to the abutment 10 side (left side in FIG. 3A) with respect to the cylindrical body 24. That is, at this position, the relative displacement of the bridge girder 14 with respect to the abutment 10 is limited, and the relative displacement amount is kept within a certain range.
[0043]
If the bridge girder 14 is further displaced from this position in the direction away from the abutment 10 due to, for example, an earthquake, the displacement is only absorbed by the elastic deformation of the cushioning material 40, and the cable 16 and the ring 30 The load acting on the rocket rises sharply. 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 main body 32 to lose the load, and the temporary stopper plate 34 is removed. Only the ring main body 32 is fitted into the cylindrical body 24 leaving 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 this 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 main body 32 approaches the stopper 22 while being deeply fitted into the cylindrical body 24 (FIG. 3B). Since the cushioning material 27 provides a movement resistance to the cable, the energy given to the cable 16 and the ring main body 32 is effectively absorbed, and a buffering effect is exerted (in the illustrated example, the cushioning material 27 is advanced as the ring main body 32 advances). Is gradually discharged from the cylinder 24).
[0045]
Thereafter, when the ring main body 32 comes into contact with the support 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. The end bridge 14 is prevented from dropping from the abutment 10 by maintaining the connection state with the abutment 10.
[0046]
When the cushioning material 27 is a solid material such as rubber, the position where the cushioning material 27 is sandwiched between the support plate 22 and the ring main body 32 in a state where the cushioning material 27 is contracted and deformed to the limit is the position of the ring main body 32. It is the final locking position.
[0047]
In the device described above, the displacement limit is released by shearing the base portion of the temporary stopper plate 34 formed integrally with the ring main body 32 as the fitting member. It is easier to set a load when the displacement restriction is released than in a structure in which the displacement restriction is released by breaking. 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 base portion), the load when the displacement limitation is released can be easily reduced. 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 assembling 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-described device, the tubular body 24 is fixed to the bridge girder 14 side, and the ring body 32 is relatively displaced in the axial direction together with the cable 16 with respect to the tubular body 24, so that 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 structure in which a plurality of guide portions 26 extend forward from the cylindrical body 24 and these guide portions 26 are inserted into the through holes 36 on the side of the temporary stopper plate 34. With this configuration, 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 stoppers) By setting the ratio to the circumferential length of the portion where the plate 34 is connected to the fitting member), it is possible to more easily design the shear load (load for releasing the displacement limitation) of the temporary stopper plate 34.
[0051]
Further, as described above, the temporary stopper plate 34 is projected radially outward from the ring main body 32, so that the temporary stopper plate 34 and the spring seat plate 28 on the cylindrical body side (for example, even at the portion on the support plate 22 or the bridge girder 14 side). ) Can be interposed between the compression coil spring 38 and the elastic force of the compression coil spring 38, so that the cable 16 can be maintained in a tensioned state to some extent regardless of the displacement of the ring 30. ing.
[0052]
In the present invention, the means for fixing the fitting member to the connecting member does not matter. For example, as shown in FIG. 6 as a second embodiment, the nut 29 shown in FIG. The temporary stopper plate 34 may be made to protrude radially outward from the outer peripheral surface of the pipe 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 temporary stopper portion formed over the entire circumference as in the illustrated temporary stopper plate 34. For example, the temporary stopper portion may have a plurality of projections radially projected from the fitting member. It is possible to obtain the operation of limiting the displacement of the temporary stopper portion and releasing the displacement limit by shearing the temporary stopper portion.
[0054]
A third embodiment of the present invention will be described with reference to FIGS. In the figure, the basic structures of the cable 16, the support plate 22, the cushioning material 40, and the cylindrical body 24 are the same as those shown in FIG. 1, and the description thereof will be omitted.
[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 second embodiment, but the outer peripheral surface of the nut 29 is temporarily Instead of protruding the stopper portion 34, a ring-shaped protruding ridge 25 extending over the entire circumference is protruded inward at a plurality of positions arranged in the axial direction on the inner peripheral surface of the cylindrical body 24. At the position where the nut 29 abuts on the ridge 25a (FIG. 7A) closest to the distal end of the cylindrical body, the relative displacement of the nut 29 and the cable 16 with respect to the cylindrical body 24 during normal use is limited. .
[0056]
In this structure, when a large tensile load exceeding a certain level acts on the cable 16 further from the position shown in FIG. 7A due to an earthquake or the like, the leading edge ridge 25a is sheared by losing the tensile load, and the nut 29 is accordingly reduced. Penetrates into the inside of the cylindrical body 24. Thereafter, the nut 29 is inserted deeply into the cylindrical body 24 while sequentially shearing the ridges 25 arranged in the axial direction, and the energy given to the nut 29 and the cable 16 is absorbed each time the shearing is performed, and the buffering effect is obtained. Is exerted (FIG. 6B). Then, the nut 29 and the cable 16 are locked at a position where the nut 29 abuts on the support plate 22, and the bridge is prevented from being dropped (FIG. 3 (c)).
[0057]
In this device, the displacement limit is released by the shearing of the ridge 25a protruding from the inner surface of the cylindrical body 24. Therefore, similarly to the device described in the first embodiment, the thickness of the ridge 25a is reduced. By setting, it is possible to easily and appropriately determine the load when the displacement limitation is released, and there is an advantage that the number of parts is small, the structure is simple, and the assembly is easy.
[0058]
Further, in the above-described device, the tubular body 24 is fixed to the bridge girder 14 side, and the ring body 32 is relatively displaced in the axial direction together with the cable 16 with respect to the tubular body 24, so that 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]
Further, in this embodiment, the nut 29 is fitted 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 effectively absorbed and a remarkable buffering effect can be obtained.
[0060]
The ridges 25 for absorbing energy are not necessarily formed over the entire circumference. For example, the ridges 25 may be scattered at a plurality of positions arranged in the circumferential direction, or may be spirally formed in the axial direction of the cylindrical body 24. It may be a shape that progresses in a shape.
[0061]
Also, the protrusion 25a for limiting displacement is not necessarily formed over the entire circumference, but 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 to apply an outward urging force to the nut 29 and the cable 16 (an urging force in a direction away from the other bridge member). You may make it give.
[0063]
【The invention's effect】
As described above, according to the present invention, it is possible to determine the load when the displacement limitation is released only by setting the cross-sectional area of the shear portion of the temporary stopper, and the structure is simple and the assembly is easy. There is an effect that it is easy. In addition, the cylinder is fixed to the bridge member side and does not require any means for guiding it. This has the effect that the movement of the connecting member can be made smoother than in the conventional device.
[Brief description of the drawings]
FIG. 1 is a sectional front view of an apparatus for preventing a bridge from falling with a displacement limiting function according to a first embodiment of the present invention.
FIG. 2 is a sectional view taken along line AA of FIG.
FIGS. 3 (a) to 3 (c) are cross-sectional front views showing the operation of the bridge prevention device.
FIGS. 4 (a) and 4 (b) are partial cross-sectional front views showing examples of installation of the bridge-fall prevention device.
FIG. 5 is a graph showing a relationship between a load acting on a cable and a displacement in the fall prevention device.
FIG. 6 is a sectional front view of a device for preventing a falling bridge with a displacement limiting function according to a second embodiment of the present invention.
FIG. 7 is a sectional front view of a device for preventing a bridge from falling with a displacement limiting function according to a third embodiment of the present invention.
[Explanation of symbols]
10 Abutment (Bridge material)
14 Bridge girder (bridge member)
16 Cable (connecting member)
17 Male thread
18 Fixing device
20 Falling bridge prevention device
22 Support plate (stopper)
23 Bolt insertion hole
24 cylinder
25 ridges (energy absorbing material)
25a ridge (temporary stopper)
26 Guide
27 Buffer material (energy absorbing material)
28 Spring seat plate
29 nut (fitting member)
30 rings
32 Ring body (fitting member)
34 Temporary stopper plate
36 Through hole
38 Compression coil spring
40 cushioning material

Claims (7)

While limiting the relative displacement between the bridge members constituting the bridge within a specific allowable displacement range, the relative displacement exceeding the allowable displacement range is allowed when a load of a predetermined value or more is applied in a direction in which the two component members are separated from each other. A bridge member with a displacement limiting function that regulates the relative displacement within a range in which the bridge member can be prevented from falling while being fixed to a connecting member that connects the bridge members and at least one of the bridge members A tubular body into which the connecting member is inserted, and a fitting member provided on the connecting member and having a shape capable of fitting into the tubular body, and a bridge at the other end of the tubular body. A stopper is provided at an end closer to the member to prevent the fitting member from moving in the fitting direction, and a temporary stopper portion projects radially outward from the fitting member. By contacting the end of the cylindrical body opposite to the stopper, the movement of the fitting member in the direction of fitting into the cylindrical body is restricted, and when a load equal to or more than a certain amount acts in the fitting direction. A fall prevention device with a displacement limiting function, wherein the temporary stopper portion is broken and the fitting member is fitted into the cylinder to a position where the fitting member is prevented from moving by the stopper. 2. The device according to claim 1, wherein the temporary stopper is formed in a plate shape having a constant thickness. 3. 3. The drop bridge prevention device with a displacement limiting function according to claim 1, wherein the temporary stopper portion is formed over the entire circumference of the fitting member, and is intermittent in a circumferential direction at a base portion connected to an outer peripheral portion of the fitting member. A plurality of guide portions having a shape capable of being inserted into each of the through holes from an end of the end of the cylindrical body opposite to the stopper are provided. A displacement limiting function, which extends along the axial direction of the cylindrical body, and the moving direction of the temporary stopper and the fitting member connected thereto is restricted in the axial direction of the cylindrical body by the insertion of the guide portion. Falling bridge prevention device. The device for preventing a bridge from falling with a displacement limiting function according to any one of claims 1 to 3, wherein the fitting member is provided around the cylindrical body between the cylindrical body or a bridge member and the temporary stopper portion. A fall prevention device with a displacement limiting function, comprising a spring member for urging the insertion member away from the stopper. While limiting the relative displacement between the bridge members constituting the bridge within a certain range, the bridge member falls while absorbing energy of the load when a certain load or more is applied in a direction in which both the constituent members are separated from each other. A bridge member that connects the bridge members to each other, a cylinder fixed to at least one of the bridge members, and through which the connection member is inserted, and a connecting member. And a fitting member having a shape capable of being fitted into the cylindrical body, wherein the movement of the fitting member in the fitting direction is performed at an end of the cylindrical body closer to the other bridge member. A stopper is provided, and a temporary stopper portion protrudes radially inward from the other end, and the temporary stopper portion comes into contact with the fitting member to be fitted into the cylinder. The movement of the fitting member is restricted, and the temporary stopper portion is broken when a load equal to or more than a certain amount acts in the fitting direction, and the fitting member is fitted into the cylinder to a position where the fitting member is prevented from moving by the stopper. A fall prevention device with a displacement limiting function, characterized in that the device is configured to be operated. The device for preventing a bridge from falling with a displacement limiting function according to any one of claims 1 to 5, wherein energy absorption is performed by giving resistance to movement of the insertion member in a direction in which the insertion member is inserted into the cylinder. A bridge prevention device with a displacement limiting function, characterized by being provided with a material. 7. The falling bridge prevention device with a displacement limiting function according to claim 6, wherein an energy absorbing projection protruding inward at a position closer to the stopper than the temporary stopper is formed on an inner peripheral surface of the cylindrical body. A fall prevention device with a displacement limiting function, wherein the fitting member is fitted into the cylinder while shearing and breaking the projecting portion.

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