JP2000283220A - Base isolation display stand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exert damping force corresponding to the weight of a base-isolated object at the time of isolation action, in a base isolation display stand protecting the base-isolated object from earthquakes and the like by base isolation of an upper base on which the base-isolated object such as an art object is placed. SOLUTION: A sliding support 7 and a rolling support 9 are provided in parallel between an upper base 3 on which a base-isolated object is placed and a lower base 5 provided below the upper base 3. A load acting on the low base 5 from the upper base 3 is supported by these supports 7, 9, and relative horizontal vibration of both bases 3, 5 is isolated. The sliding support 7 maintains vertical intervals between both bases 3, 5, and supports the load acting from the upper base 3. The rolling support 9 supports the load acting from the upper base generally constant through a pressing member 11 elastically urging the rolling support 9 to either one of the base 3 or 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a base-isolated display stand for seismically isolating an upper base on which a seismic isolated object such as an art object is placed to protect the seismic isolated object from an earthquake disaster or the like. The present invention relates to a seismic isolation display on which a damping force according to the weight of the seismic isolation target acts during operation.

[0002]

2. Description of the Related Art Conventionally, seismic isolation display stands have been known for seismic isolation of works of art or the like that need protection against external vibrations such as earthquakes.

[0003] The seismic isolation display is usually provided with an upper base on which the seismic isolation target is placed, a lower base fixed to the floor, and both bases for allowing relative horizontal movement between the two bases. A rolling bearing interposed between the base and a sliding bearing acting as a friction damper for damping relative horizontal vibration between the two bases;
A return coil spring is interposed between the bases to restore the original position while restraining the relative horizontal movement. The rolling bearing supports the upper base while maintaining the vertical distance between the two bases,
The sliding bearing includes a friction member that slides on the lower base while supporting the upper base, and a resilient member interposed between the friction member and the upper base. By pressing against the lower base with a constant load by the member and supporting the load acting from the upper base almost constant, the frictional resistance between the friction member and the lower base generated at the time of sliding is always kept constant, and the constant constant damping Force is working. Therefore, since the remaining weight of the seismic isolation target is supported by the rolling bearing having extremely small sliding friction resistance with the lower base, the vibration damping force is substantially determined by the friction member. That is, the conventional seismic isolation display stand is configured so that a constant damping force always acts regardless of the weight of the seismic isolation target object. Usually, the damping force is adjusted by adjusting the elastic force of the elastic member and adjusting the friction coefficient by changing the material of the friction member so that the desired seismic isolation effect can be obtained.

[0004]

However, in the seismic isolation display stand having the above-described structure, the vibration damping force is constant regardless of the weight of the seismic isolation target object, so that exhibitions such as museums change. When the seismic isolation target object changes and its weight (mass) changes, the vibration damping performance and seismic isolation performance of the seismic isolation display stand also change. For example, when the weight of the seismic isolation target increases, the inertial force acting on the seismic isolation target in the horizontal direction at the time of vibration increases, so that the vibration of the seismic isolation target hardly attenuates. On the other hand, when the weight of the seismic isolation target is reduced, that is, when the damping force is large with respect to the mass of the seismic isolation target, the vibration wave of the earthquake is directly input to the seismic isolation target and sufficient There is a possibility that the seismic isolation effect is not obtained and the seismic isolation target collapses.

[0005] Therefore, every time a display item changes, it is necessary to adjust the resilient force acting on the friction member to adjust the damping force, which requires a great deal of labor and labor.

The present invention has been made in order to solve the above problems, and an object of the present invention is to seismically isolate an upper base on which a seismic isolation target such as a work of art is placed so as to remove the seismic isolation target. It is an object of the present invention to provide a seismic isolation display stand that protects against earthquake disasters, in which a damping force according to the weight of the seismic isolation target acts during seismic isolation operation.

[0007]

In order to achieve the above object, a seismic isolation display according to the present invention comprises an upper base on which an object to be isolated is placed, and a lower base provided below the upper base. A seismic isolation display in which a sliding bearing and a rolling bearing are juxtaposed to support the load acting on the lower base on the lower base, while isolating relative horizontal vibration between the two bases. In the stand, the sliding bearing supports the load acting from the upper base while maintaining the vertical distance between the two bases, and the rolling bearing is supported by a pressing member that elastically urges the base against one of the bases. The load applied from the upper base is supported substantially uniformly.

According to the above configuration, when horizontal vibration is input to the seismic isolation display table due to an earthquake or the like, the upper base and the lower base are moved in the horizontal direction in order to isolate the seismic isolation target object from the vibration. , The horizontal vibration is attenuated. At this time, since the sliding friction resistance of the sliding bearing that slides with respect to the lower base or the upper base is large and the rolling friction resistance of the rolling bearing that rolls is small, the horizontal vibration is mainly caused by the sliding friction resistance of the sliding bearing. Acts as a damping force and is damped.

The weight of the seismic isolation target is distributed and supported by a sliding bearing and a rolling bearing via an upper base. The sliding bearing supports a load while maintaining the vertical distance between the two bases. In addition, the rolling bearing supports the load substantially uniformly through a pressing member which resiliently urges the rolling bearing within a predetermined vertical distance, that is, the rolling bearing is always provided with the above-mentioned rolling bearing. Since only a constant load urged by the pressing member is supported, the sliding bearing supports the remaining weight of the seismic isolation target excluding the constant load.

Therefore, when the weight of the seismic isolation object changes, the load supported by the sliding bearing changes proportionally, and as a result, the sliding frictional resistance between the sliding support and the upper base or lower base sliding on the sliding support also increases. Change. That is, the damping force changes in proportion to the weight (mass) of the seismic isolation target. Therefore, it is not necessary to adjust the damping force to correspond to the weight of the seismic isolation target, and it is possible to suppress the transmission of vibration to the seismic isolation target and minimize the variation in vibration damping performance. .

Further, the seismic isolation display stand according to claim 2 of the present invention is characterized in that the pressing member is a coil spring or a disc spring.

According to the above configuration, the shape of the coil spring,
That is, by setting the wire diameter, the winding diameter, the number of windings, etc., and also for the disc spring, by setting the diameter, thickness, height, number of sheets, the direction of superposition, etc. of the disc spring,
Since the rolling bearing can easily adjust the supporting load for supporting the seismic isolation target, when a specific weight of the seismic isolation target is placed, damping force (hereinafter, referred to as friction resistance) generated in the sliding bearing. The reference damping force can be easily adjusted.

[0013] In addition, by adjusting the initial deflection applied to the coil spring and the disc spring in advance, that is, the deflection at the time of supporting the seismic isolation target, the adjustment can be similarly easily performed.

[0014]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a plan sectional view taken on line II of FIG. 2 showing one embodiment of a seismic isolation display according to the present invention, and FIG.
FIG. 2 is a sectional view taken along line IIb-IIc-IId. Also,
FIG. 3 is an enlarged side sectional view of a main part of a part III in FIG.
FIG. 4 is a side sectional view showing a modification of FIG. 3.

As shown in FIGS. 1 to 3, the seismic isolation display 1 of this embodiment has an upper base 3 on which an object to be isolated is placed.
And four bearing units 17 each having a sliding bearing 7 and a rolling bearing 9 arranged side by side between the lower base 5 provided below the upper base 3 and the lower base 5. By supporting the load applied from the base 3 to isolate the relative horizontal vibration of the upper base 3 and the lower base 5, four return coil springs 2 are provided between the upper base 3 and the lower base 5. It is configured to intervene and return to the restoration position while restraining the relative horizontal displacement between the upper base 3 and the lower base 5.

The upper base 3 is composed of a frame 3a in which an angle member having an L-shaped cross section is framed in a square shape, a pair of opposed angle members among the frame member 3a, and two reinforcing members 3b having a rectangular prism in cross section. Are hung in parallel at a distance from each other and fixed,
Further, a lower frame 3d is fixed to the center of the two reinforcing members 3b in the longitudinal direction by bridging a reinforcing member 3c having a rectangular prism in cross section, and an L-shaped cross section fixed to four corners of the lower frame 3d. Angle material 3e and this angle material 3
e, a frame 3f having the same shape and the same size as the frame 3a, the frame 3 being made of an angle material having an L-shaped cross section and fixed to the upper surface of the frame 3e.
f, and a rectangular plate 3g fixed to the upper surface of f.

The lower base 5 is a square plate fixed to the floor surface 15 and having the same shape and the same size as the frame 3a. The upper base 3 and the lower base 5 are overlapped in a plan view. The state is the restoration position.

The seismic isolation display 1 of this embodiment is provided with a lock bolt 6 for fixing the upper base 3 and the lower base 5 so that they cannot move relative to each other horizontally and vertically. The lock bolt 6 is inserted through the reinforcing member 3b of the upper base 3 so that the head 6a of the lock bolt 6 and the upper surface of the reinforcing member 3b are locked, and the lower end 6b and the lower base 5 are connected. By screwing, the upper base 3 and the lower base 5 are fastened and fixed. Needless to say, it is mainly used during transportation and is removed when the seismic isolation display table 1 is used.

The bearing unit 17 is formed by integrating the sliding bearing 7 and the rolling bearing 9 into one compact unit. The upper base 3 is provided to evenly support the weight of the seismic isolation target. And four lower bases 5 in parallel. That is, on the lower surface of the reinforcing member 3b,
It is fixed at a position on the diagonal line of the upper base 3 and at the same distance from the intersection of the diagonal line which is the center of the upper base 3. The lower base 5 can be freely displaced relative to the lower base 5 while maintaining the vertical distance between the upper base 3 and the lower base 5, so that if an acceleration due to an earthquake or the like is transmitted from the outside, Each support unit 17 slides on the lower base 5 to support the upper base 3 in a seismic isolation state, thereby reducing acceleration transmitted to the seismic isolation target and preventing the seismic isolation target from collapsing.

The four return coil springs 2 are arranged in a cross shape in plan view so as to extend in the direction opposite to the upper base 3 and the lower base 5. One end of each of the returning coil springs 2 is hooked on a spring hooking member 25 provided near the center of the lower base 5, and the other end thereof is provided on a spring hooking member 27 provided on the frame 3 a of the upper base 3. And used as a tension spring.

The four return coil springs 2
Since they are formed in the same shape (the wire diameter, the winding diameter, and the number of turns are the same), the respective spring forces are the same, and the upper base 3 and the lower base 5 have four return coils. The spring 2 is urged in a direction to return to a restoring position where the spring force is balanced. Therefore, when a vibration such as an earthquake is input to the lower base 5, the lower base 5 is relatively displaced with respect to the upper base 3, and each coil spring 2 is pulled in the displacement direction. To the original position where the spring force of the return coil spring 2 is balanced. This return coil spring 2 is selected by selecting a coil spring having an appropriate spring constant.
The natural period of the relative horizontal vibration between the upper base 3 and the lower base 5 is adjusted to be longer than the natural period of the shaking of the earthquake.

As shown in FIG.
A case 13 which forms the outer shape of the bearing unit 17 comprises a sliding bearing 7 having a predetermined coefficient of friction for sliding with the lower base 5 and a rolling bearing 9 having a ball bearing structure.
The support unit 17
Is fixed to the lower surface of the reinforcing member 3b of the upper base 3 by screwing, and the lower surface of the support unit 17 is in contact with the lower base 5 so as to freely slide and roll in the horizontal direction. When horizontal vibration is input to the seismic isolation display 1, the lower base 5
, The sliding bearing 7 slides and the rolling bearing 9 rolls.

The sliding bearing 7 is a ring-shaped friction member 7.
The screw is fixed to the lower surface of a bottomed cylindrical case 13 that is open at the bottom and forms the outer shape of the bearing unit 17. The upper surface of the case 13 is
And the lower surface of the friction member 7 is in contact with the lower base 5. That is, the sliding bearing as the friction member 7 always keeps the distance between the upper base 3 and the lower base 5 constant by the case 13.

A flange having a circular flange is integrally formed on the upper surface of the case 13, and the reinforcing member 3b of the upper base 3 is provided at the center of the upper surface of the flange.
Male screw 2 screwed with female screw 19 provided through
1 are integrally formed. A rectangular nut 23 for preventing rotation is screwed into a male screw 21 which is screwed with the female screw 19 and protrudes from the upper surface of the reinforcing member 3b.
And the upper base 3, ie, the bearing unit 17 and the upper base 3.
Are fastened and fixed.

Also, on the inner circumferential surface of the case 13,
The rolling bearing 9 is fitted and mounted slidably in the up-down direction.
The rolling bearing 9 has a steel ball 9a and a cylindrical outer shape which supports the ball 9a so that the ball 9a can roll freely from above and is slidably fitted to the inner peripheral surface of the case 13 in the vertical direction. And a ball bearing portion 9b. The steel ball 9a is in contact with the lower base 5 through the hole 4 formed in the center of the friction member 7, and while supporting the load applied from the upper base 3 almost uniformly, Upper base 3
Is rolled in the horizontal direction while supporting it with a constant load, and the frictional resistance during the rolling is set to be extremely small with respect to the sliding frictional resistance of the frictional member 7.

The constant load is applied to the ball bearing 9b.
Is provided between the upper surface of the case 13 and the inner bottom surface 13a of the case 13 by pressing the ball bearing portion 9b downward by interposing a coil spring 11 having an initial flexure.

When the ball 9a of the rolling bearing 9 is in contact with the lower base 5, the friction member 7
And the rolling bearing 9 do not come into contact with each other, but have a constant gap 8 therebetween.

The coil spring 11 and the friction member 7 are
Considering the weight range of the seismic isolation object that may be placed, the reference damping force at a certain reference weight is determined within that range so that the desired seismic isolation performance and damping performance can be obtained. In addition, it is selected so as to have the reference elastic force and the coefficient of friction as the constant load. That is, the material and shape of the coil spring, that is, the wire diameter, the winding diameter, the number of windings, and the like are set so that the reference elastic force is obtained. Further, a material having a friction coefficient such that a reference damping force can be obtained by the elastic force is selected. However, the case 13 and the ball bearing 9b
Depending on the manufacturing accuracy, the initial deflection may not be set to the reference elasticity even if the initial deflection is set to the desired value. Finally, a shim is interposed between the coil spring 11 and the ball bearing portion 9b. By mounting, the initial deflection of the coil spring 11 at the time of assembling in the case 13 is finely adjusted to be adjusted to the reference damping force.

FIG. 4 is a side sectional view showing a modified example of the bearing unit when a disc spring is used as a pressing member.

In this modification, a coned disc spring 11 'is applied in place of the coil spring 11 in the first embodiment, and the components are the same. Only the differences will be described.

As shown in FIG. 4, inside the case 13 of the bearing unit 17, instead of the coil spring 11 in FIG. 3, a disc spring laminate is provided.

In the present embodiment, this disc spring laminate is a disc spring unit 1 made of frusto-conical spring steel having a hole in the center.
Six 1's are alternately stacked in the opposite direction, but basically, the diameter, plate thickness, height, number of sheets,
The direction of superposition and the like are set.

As shown in FIG. 5, the disc spring unit 11 'has a region in which the resilient force varies little with respect to the bending deformation of the disc spring (hereinafter, referred to as a "resilient force variation dead zone"). To exhibit this characteristic, the ratio of the thickness t of the spring to the height H, H / t ／ 1.4, is appropriate. This disc spring 11 '
Has the elasticity fluctuation dead zone, so that the elasticity can be easily set. That is, as described above, depending on the manufacturing accuracy of the case 13 or the like, final shim adjustment is required. However, in the elasticity fluctuation dead zone, even if the bending varies by the manufacturing accuracy, the elasticity does not change. It is difficult to do so, and shim adjustment can be omitted.

In FIGS. 3 and 4, the screws are not shown in order to prevent the figures from being complicated, but these screws are buried in counterbore holes formed on the lower surface of the friction member 7. Needless to say, it does not come into contact with the lower base 5.

Next, the operation of the seismic isolation display stand according to this embodiment will be described with reference to FIGS.

When a horizontal vibration is input to the seismic isolation display table 1 due to an earthquake or the like, the upper base 3 and the lower base 5 are pressed against the spring force of the return coil spring 2 which is the restoring force to the restoring position. While repeating relative horizontal vibration,
The vibration is attenuated.

At this time, the sliding frictional resistance of the sliding bearing 7 which slides with respect to the lower base 5 is large, and the rolling rolling bearing 9 which rolls is provided.
, The horizontal vibration is attenuated mainly by the sliding frictional resistance of the sliding bearing 7 acting as a damping force.

The weight of the seismic isolation object is supported by the bearing unit 17 via the upper base 3, but the bearing unit 17 is composed of the sliding bearing 7 and the rolling bearing 9. The weight is distributed and supported by the sliding bearing 7 and the rolling bearing 9. Here, the sliding bearing 7 supports the load by keeping the vertical distance between the upper base 3 and the lower base 5 constant by the case 13, and the rolling bearing 9 is a ball bearing part. A coil spring 11 with an initial flexure is interposed in a predetermined space between the upper base 3 and the upper base 3. Thus, the load acting from above is supported almost constant, that is, only the constant load of the above-mentioned weight is always supported. Therefore,
The sliding bearing 7 is adapted to support the remaining weight excluding the constant load via the case 13.

For this reason, when the weight of the seismic isolation target changes, the load supported by the sliding bearing 7 changes proportionally, and as a result, the sliding friction resistance between the sliding bearing 7 and the lower base 5 also changes proportionally. . That is, the damping force changes in proportion to the weight (mass) of the seismic isolation target. Therefore, even if the weight of the seismic isolation target changes, the seismic isolation performance that suppresses the transmission of vibration to the seismic isolation target is maintained without adjusting the damping force.
Variations in the decay time until the vibration decay converges can be reduced.

For example, if the seismic isolation target becomes heavy,
Since the inertial force acting on the seismic isolation target in the horizontal direction at the time of vibration also becomes large, the vibration is usually difficult to be damped. Variation in decay time can be reduced.

On the contrary, the weight of the seismic isolation target is reduced,
That is, when the damping force is large with respect to the mass of the seismic isolation target, the vibration wave of the earthquake is usually directly input to the seismic isolation target, and a sufficient seismic isolation effect is not obtained. Although there is a possibility that the object may collapse, in the present embodiment, the damping force is also reduced in proportion to the upper base 3 and the lower base 5.
And the vibration wave is suppressed from being input to the seismic isolation target, and the collapse can be prevented as much as possible.

As described above, the seismic isolation display table 1 of this embodiment
Means that the damping force during seismic isolation operation changes according to the weight of the seismic isolated object, so even if the museum or other event changes and the weight of the seismic isolated object changes, the damping force It is possible to reduce the variation in the seismic isolation performance and the damping performance without making adjustments. For this reason, there is no need to adjust the damping force that was implemented each time the seismic isolation target changes,
Significant work load reduction is possible.

In the embodiment described above,
The following excellent effects are also exhibited. The bearing unit is
It is a configuration in which the sliding bearing 7 and the rolling bearing 9 are integrated,
It is compactly manufactured with one mechanical element by incorporating the above two functions. For this reason, the seismic isolation display can be installed more efficiently than in the conventional case where the rolling bearing and the sliding bearing are separately mounted, and the construction time can be greatly reduced. In addition, since it is compact, it can be installed even in a small installation space, so that the bearing units can be easily arranged on the seismic isolation display table, and the degree of freedom in designing the seismic isolation display table increases.

Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and various modifications can be made without departing from the gist of the present invention.

For example, in the present embodiment, an explanation has been given in which an object such as an exhibit is directly placed on the upper base 3. However, the present invention is not limited to this. Exhibits may be placed via a suitable mounting table, pedestal, or the like.

Although the coil spring 11 and the disc spring 11 'have been disclosed as the pressing members, the present invention is not limited thereto, as long as the members have a high resilience. A leaf spring or a rubber-based member may be used.

Further, in this embodiment, the bearing unit 17 in which the sliding bearing 7 and the rolling bearing 9 are integrated is used in consideration of easiness of mounting and the like. However, the present invention is not limited to this case, provided that the rolling bearings that urge a constant load to any of the bases by the pressing member are provided side by side. The sliding bearings 7 and the rolling bearings 9 are provided completely independently. May be.

Further, in the present embodiment, four return coil springs 2 are arranged in a substantially cross shape in a plan view so as to extend in the opposite direction of the two bases 3 and 5, and the four support units 17 are provided. Are arranged on the diagonal line of the bases 3 and 5, however, the present invention is not limited to this as long as they do not interfere with each other. Conversely, the coil spring 2 is arranged on the diagonal line, and the support unit 17 is mounted. You may arrange | position to the opposite side.

[0049]

As described above, according to the seismic isolation display of the first aspect of the present invention, the seismic isolation operation is performed in proportion to the weight of the seismic isolation target placed on the seismic isolation display. Since the damping force is changing, entertainment such as art museums change,
Even if the weight of the seismic isolation target changes, it is possible to reduce the variation in the damping performance while maintaining the seismic isolation performance without adjusting the damping force. For this reason, there is no need to adjust the damping force that was implemented each time the seismic isolation target changes,
Significant work load reduction is possible.

Further, since the damping force is automatically adjusted only by changing the seismic isolation target, a reliable seismic isolation / damping operation can be performed without human error such as improper adjustment of the damping force. Can be guaranteed.

According to the seismic isolation display stand of the second aspect of the present invention, since the coil spring or the disc spring is used for the pressing member, the shape of the coil spring and the disc spring is set, and the coil is formed. The reference damping force can also be easily adjusted by adjusting the initial deflection of the spring and the disc spring when supporting the seismic isolation target. Accordingly, the damping force can be adjusted reliably and in a short time.

[Brief description of the drawings]

FIG. 1 is a plan sectional view taken on line II of FIG. 2 showing an embodiment of a seismic isolation display according to the present invention.

FIG. 2 shows IIa-IIb-IIc-IId in FIG.
FIG. 3 is a side sectional view taken along line arrows.

FIG. 3 is an enlarged view of a main part of a part III in FIG. 2,
It is a side cross section which shows a bearing unit.

FIG. 4 is a side sectional view showing a modification of the bearing unit, in which a disc spring is used as a pressing member.

FIG. 5 is a conceptual diagram showing spring characteristics of a disc spring used as a modification of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Seismic isolation display stand 3 Upper base 3a Frame 3b Reinforcement 3c Reinforcement 3d Lower frame 3e Angle 3f Frame 3g Rectangular plate 4 Hole 5 Lower base 7 Friction member (sliding bearing) 9 Rolling bearing 9a Ball 9b Ball bearing Reference Signs List 11 Coil spring (pressing member) 11 'Disc spring (pressing member) 13 Case 13a Internal bottom surface 15 Floor surface 17 Support unit

Claims (2)

[Claims] 1. A sliding bearing and a rolling bearing are juxtaposed between an upper base on which a seismic isolation target is placed and a lower base provided below the upper base. While supporting the load acting from the upper base,
In the seismic isolation display stand configured to isolate the relative horizontal vibration between the two bases, the sliding bearing supports a load acting from the upper base while maintaining a vertical interval between the two bases, and the rolling bearing is A seismic isolation display stand characterized in that the load applied from the upper base is supported substantially uniformly via a pressing member that elastically urges the base. 2. The seismic isolation display stand according to claim 1, wherein the pressing member is a coil spring or a disc spring.