JP3153205B2 - Drop bridge prevention shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber for preventing a bridge from being dropped and having a connecting rod bridged between adjacent bridge girders.

[0002]

2. Description of the Related Art When an earthquake occurs, an impact force due to its high energy acts, and a bridge structure is damaged by a dropping bridge or the like due to vibration caused by the impact force, thereby causing great damage. Conventionally, as a buffering device for preventing girder is shown open in JP-A-10-131123,
Various types have been developed, such as a bracket that connects a connecting cable such as a PC cable or a tubular connecting rod to a bridge girder, and a shock absorber that combines a spring and a cushioning member such as elastic rubber at the end of the bridge girder. .

[0003] In this conventional dropping prevention shock absorber, when a strong impact force is applied to the connecting rod along the pulling direction, in addition to the elastic action of the spring, the shock force is safely received by the shock absorbing member. In this way, the damping device is prevented from being damaged, and the connection between the bridge girders by the connecting rod is to be maintained.

[0004]

However, the buffering effect of the above-mentioned conventional bridge-preventing shock absorbing device emphasizes only the effect of alleviating the tensile horizontal impact force of the connecting rod along the axial direction of the bridge girder. It's just something. However, when a large earthquake occurs, complex vibration effects occur on the piers, etc., and displacements and deformations beyond expectations are added to the bridge girder, for example,
The connecting end of the bridge girder may be displaced vertically or vertically in this horizontal plane with respect to the tension horizontal direction of the connecting rod. At this time, the impact force due to the earthquake is applied to an arbitrary direction inclined with respect to the axial direction of the connecting rod, whereby the intermediate portion of the connecting rod may be angularly displaced in an arbitrary direction. In such a case, the conventional bridge-fall prevention shock absorber cannot sufficiently cope with the problem, and damage such as the shock absorber or bending of the connecting rod occurs.

Therefore, according to the present invention, in addition to exerting a shock-absorbing effect when the impact force is applied in the tension horizontal direction of the connecting rod, even when the impact force is applied in a direction causing an angular displacement of the connecting rod, An object of the present invention is to provide a shock absorber for preventing a bridge from falling without generating concentrated stress on the connecting rod.

[0006]

In order to achieve the above-mentioned object, according to the present invention, there is provided a shock absorbing device for preventing a bridge from falling, wherein the shock absorbing device has an end portion of a connecting rod fixed to an end portion of a bridge girder through a bracket. Plate, a supporting plate attached to the outer end of the penetrating connecting rod, and a spring interposed between the supporting plate and the cushioning plate. In this case, the bracket is provided with a through-hole, and the connection is inserted through the through-hole and the through-hole. A cylindrical bush is provided between the rod and the bush, and the bush is formed into a curved surface whose inner surface protrudes inward .
Along with one end of this bush,
A protruding part is provided that protrudes in the direction.
The bush is arranged at the intermediate side of the connecting rod.
It is fixed to the bracket by the fixing plate, when the angular displacement is generated in the middle portion of the connecting rod, by being received by the curved inner surface portion and the buffer fixing plate of the bushing, the through-hole location of the bracket It is characterized in that concentrated stress is prevented from being generated in the connecting rod.

According to the above-described shock absorber for preventing a bridge from falling according to the present invention, when the bridge girder moves horizontally due to an earthquake and a large impact force is applied to the connecting rod, in the initial stage,
The impact force is reduced by the elasticity of the spring, and when the magnitude of the impact force is large, the impact force is reduced by the elasticity of the buffer plate while the support plate collides with the buffer plate. In addition to such impact force,
When an impact force is applied in a direction inclined with respect to the axial direction of the connecting rod, the connecting rod abuts at the position of the through hole of the bracket to be in an angular displacement state. The intermediate portion of the rod is received along the curved shape of the inner surface of the bush, so that stress concentration at the bent portion is avoided. As a result, the disconnection of the connecting rod is prevented, and furthermore, the damping device itself is prevented from being damaged.

[0008] The material for forming the bush is a material which exhibits the above-described performance and is not damaged by an excessive impact force.
For example, in addition to a metal material such as a copper alloy, an aluminum alloy, and other special steels, a synthetic resin material such as a high-density polyethylene resin can be used.

[0009]

[0010] The bush has a cylindrical portion.
At one end, an outwardly projecting peripheral portion is provided along the end face.
A bush is arranged on the intermediate part side of the connecting rod via the peripheral part.
The bush can be fixed to the bracket in a state where collision with the bracket can be avoided in a state where it can be prevented from colliding with the bracket, and the buffering action associated with the angular displacement of the intermediate portion of the connecting rod, it can be further demonstrated by the buffer fixing plate as described above.

In addition to the above-described spring holding structure other than the above-mentioned bush portion, and a component portion such as a buffer plate,
A conventional shock absorber can be used as it is.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, a buffer device 1 for preventing a bridge from falling according to the embodiment includes a buffer plate 11 having an end of a connecting rod 13 fixed to an end of a bridge girder via a bracket 2. And this penetrating connecting rod 1
3 and a spring 1 disposed between the support plate 16 and the buffer plate 11.
5 and a connecting rod 1 spanned over the adjacent bridge girder
In a shock absorber for damping the impact force with the shock absorbing plate 11 and the spring 15 to prevent the bridge from falling even if the impact force is applied to the bracket 3, a through hole 3a is provided in the bracket 2, and the through hole 3a and the through hole 3a are provided. Connecting rod 13 inserted through 3a
The bush 6 has a cylindrical shape, and the inner surface of the bush 6 is formed into a curved surface 6a that protrudes inward.

The bracket 2 has a vertical plate 3 which is provided vertically on a seat plate 4 and supported by a connecting plate 5. A through-hole 3a is formed in the surface of the vertical plate 3, and a cylindrical portion 6b of the bush 6 is inserted into the through-hole 3a in a manner shown in FIG. One end of the cylindrical portion 6b has a projecting peripheral portion 6 protruding outward along the end surface thereof.
c is provided, and the projecting peripheral portion 6 c
It is disposed on the intermediate portion side of the connecting rod 13 and is locked in the hole edge portion of the through hole 3a. The bush 6 is thus locked to the buffer fixing plate 7 provided in the vertically plate 3 of the intermediate portion side of the circular projection 6c is the connecting rod 13
It is fixed in the state where it was set.

The buffer fixing plate 7 is a laminated material in which a steel plate 7b is adhered to an elastic plate 7a made of a chloroprene rubber material, and an insertion hole 8 is formed in the plate surface. This insertion hole 8
Is formed so that the hole edge on the elastic plate 7a side has a stepped portion 8a protruding into the hole from the hole edge on the steel plate 7b side. The above-mentioned fixing structure by the buffer fixing plate 7 is a steel plate 7b
The surface is overlapped on the intermediate portion side of the connecting rod 13 of the vertical plate 3, and these are fixed by fixing bolts 10. Head 10a of the fixing bolt 10, the buffer fixing plate 7
In a state fitted in the hole 9 formed in the
It is fixed between the steel plate 7b and the hanging plate 3. Also,
At this time, the protruding peripheral portion 6c is fitted into the step portion 8, and is substantially fixed by the elastic plate 7a.

The buffer plate 11 is disposed on the tension surface side of the vertical plate 3 in a state where the surface of the elastic plate 11a made of chloroprene material is in contact with the buffer plate 11. The steel plate 11b is laminated on the elastic plate 11a. An insertion hole 12 is formed on the surface of the buffer plate 11, and a step 12a is formed at an edge of the steel plate 11b of the insertion hole 12.

As described above, the insertion holes 9 of the buffer fixing plate 7 and the insertion holes 12 of the buffer plate 11 provided on both sides of the vertical plate 3 are provided.
Are connected to each other through a cylindrical hole of the bush 6. The connecting rod 13 is penetrated through this communication hole. End 13a of the connecting rod 13, the coil spring 15 is inserted, it is fixed by bearing capacity plate 16 and the nut 18 that the central portion is inserted a connecting rod 13. That is, a male screw is formed on the outer periphery of the end portion 13a, and the nut 18 is screwed to the male screw. One end of the coil spring 15 is fitted in the step 12a of the buffer plate 11. Further, the elasticity of the coil spring 15 can be adjusted by the nut 18. 19 is a nut 1
8 is a split pin for preventing falling off of the connecting rod end 13a.
Is inserted through the hole 14 provided in the hole.

As shown in FIG. 4, the dropping prevention buffer device 1 is attached to a side end portion of an adjacent bridge girder 20 with the connecting rod 13 being extended via the bracket 2. This mounting is fixed by riveting the seat plate 4 of the bracket 2 to the side surface of the bridge girder 20 through the hole 4a. Reference numeral 21 denotes a pier, and reference numeral 22 denotes a support for supporting an end of the bridge girder 20 below.

In general, the connecting rod 13 is stretched between the thus mounted shock absorbers 1 for preventing falling and the bridge girders 20 are connected to each other. . In addition, when an impact force acts to separate the ends of the adjacent bridge girders 20, the connecting rod 13 is in a tensile state. In this case, the support plate 16 moves along the axial direction of the connecting rod 13, and the coil spring 15 is compressed accordingly. When this impact is relatively weak, the impact is applied to the coil spring 1
5 to be absorbed. When the impact force is excessive due to a large earthquake, the support plate 16 collides with the buffer plate 11. The elastic plate 11a of the buffer plate 11 is compressed in the pressing direction and elastically or plastically deformed by the pressing action when the support plate 16 collides. Thus, the impact force acting in the axial direction of the connecting rod 13 is absorbed and reduced.

However, when a large earthquake occurs, a complicated vibration action occurs on the pier 21 and an unexpected displacement or deformation is applied to the bridge girder 20. For example, the connecting end of the bridge girder 20 is connected to the connecting rod 13. May be displaced in a vertical direction in this horizontal plane or displaced in a vertical direction with respect to the tension horizontal direction. At this time, it is assumed that the impact force due to the earthquake is applied to the connecting rod 13 in a direction inclined with respect to the axial direction while the connecting rod 13 is pulled along the axial direction. In this case, the connecting rod 13 undergoes angular displacement in an arbitrary direction.

When the connecting rod 13 is angularly displaced in this way, as shown in FIG. 5, the intermediate portion of the connecting rod 13 is received by the projecting curved surface 6a on the inner surface of the bush 6, so that the bracket 2 penetrates. At the position of the hole 3a, the occurrence of stress concentration in the connecting cable 13 is avoided.
That is, the projecting curved surface portion 6a on the inner surface of the cylindrical bush 6 can be freely displaced in any direction with respect to the intermediate portion of the angularly displaced connecting rod 13. In some cases, depending on the forming material of the bush 6,
By elastic or plastic deformation to the extent that it is not damaged, the impact force accompanying the angular displacement is reduced.

In the case where the angular displacement becomes excessively large, as shown in FIG.
Of the elastic plate 7a of the buffer fixing plate 7 is in a collision state, and the impact force accompanying the angular displacement is reduced. This also prevents direct collision between the connecting rod 13 and the bracket 2 when the connecting rod is angularly displaced, thereby preventing damage to the shock-absorbing device 1 for preventing a bridge from falling and occurrence of a cutting accident of the connecting rod 13. Thus, the function as the shock absorber can be maintained.

[0022]

As described above, since the present invention is constituted, the following effects are exhibited. That is, girder preventing damper of the present invention, the through hole in bracket is provided, the cylindrical shape of the bush is provided between the through hole and the connecting rod is inserted into the through hole, the bush Is formed into a curved surface whose inner surface protrudes inward ,
One end of this bush protrudes outward along its end face.
The projecting peripheral portion is provided, and the bushing is formed through the projecting peripheral portion.
Is connected to the buffer fixing plate arranged on the intermediate side of the connecting rod.
Therefore, since it is configured to be fixed to the bracket , not only when the impact force applied to the connecting rod acts along the axial direction of the connecting rod, but also the angle of the connecting rod in an arbitrary direction Even if displacement occurs, the bush
The connecting rod is directly bracketed by the
Therefore, it is possible to avoid applying concentrated stress to the connecting rod.

As a result, the connecting rod itself is not obstructed by bending or the like.
Harm can be prevented and the connecting rod and bra
By avoiding a direct collision with the
The device can be prevented from being damaged. this
As a result, even if a large-scale earthquake occurs,
State is maintained.

As described above, according to the shock-absorbing device for preventing a bridge from falling, the bush has an extremely simple structure that can be provided in relation to the through hole of the bracket, so that its manufacture is simple and small. Thus, it is economically advantageous.

[Brief description of the drawings]

FIG. 1 is a front elevational view in the center longitudinal section of a shock absorber for preventing a bridge falling according to the present invention.

FIG. 2 is a right side view of the same vertical cross section.

FIG. 3 is an exploded perspective view illustrating an attached state of the bush.

FIG. 4 is a partially cutaway front view illustrating a state of attachment to the bridge girder according to the first embodiment.

FIG. 5 is a fragmentary sectional front view illustrating an operation state when the connecting rod is angularly displaced.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Falling prevention buffer device 2 Bracket 3 Hanging plate 3a Through hole 6 Bush 6a Curved portion 6c Projecting peripheral portion 7 Buffer fixing plate 7a Elastic plate 7b Steel plate 11 Buffer plate 13 Connecting rod 13a Connecting rod end 15 Coil spring 16 support Press plate 18 Nut 20 Bridge girder

Claims (1)

(57) [Claims] 1. A buffer plate penetrating an end of a connecting rod fixed to an end of a bridge girder via a bracket, a supporting plate attached to an outer end of the penetrating connecting rod,
It is composed of a spring interposed between the support plate and the buffer plate. Even if the connecting rod bridged over the adjacent bridge girder receives an impact, the impact force is buffered by the buffer plate and the spring. In a shock absorber for preventing a bridge from being dropped, a through hole is provided in the bracket, and a cylindrical bush is provided between the through hole and the connecting rod inserted through the through hole. The bush is formed in a curved shape protruding inward.
At the end, there is a projecting part that protrudes outward along the end face
And the bush is connected to the connecting lock via the projecting peripheral portion.
Bracket with a buffer fixing plate located in the middle of the
When the angular displacement occurs in the middle of the connecting rod, the curved inner surface of the bush and the
By being received by the shock fixing plate, a through-hole position of the bracket, the connecting girder for preventing shock absorber rod to stress concentration is characterized in that to be able to avoid the occurrence.