JPS5836145B2 - Seismic isolation floor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seismic isolation floor for absorbing earthquake forces, external forces, or preventing forces generated from equipment from being transmitted to the outside. be.

For example, computers, emergency generators, dangerous materials (dynamite, chemicals, etc.) must be operated or stored in a safe manner even during an earthquake.

For this reason, there is a great deal of interest in earthquake-proofing devices such as frames on which such equipment is installed and places where hazardous materials are stored.

Earthquake resistance methods can be broadly divided into the following two types.

In other words, (1) nuclear power installations, spherical tanks, substation equipment, etc.
Earthquake-resistant designs that increase their strength against earthquake input (2) Absorb earthquake input with springs and keep equipment or dangerous objects installed on top of the springs in a safe state. The main focus is on what is called a seismic isolation floor.

The present invention particularly relates to the latter type of seismic isolation floor,
Conventional seismic isolation floors have a sliding surface on the floor, a spring seat plate with springs attached vertically and horizontally, and a vertical damper placed between it and the frame. Sometimes a normal locking device is provided for locking the vertical springs.

This fixing device has a structure in which the lock of the normal fixing device is released when a large earthquake input acts, and the vertical spring becomes effective.

Further, in the horizontal direction, there is no stopper, and the mechanism is such that a restoring force is provided by a tension spring fixed to a lower mounting bracket of a vertical spring and a fixed floor.

However, such prior art mechanisms have
There are the following problems.

In other words, (1) it is difficult to set the minimum acceleration at which the normal fixing device unlocks, (2) it is difficult to re-lock the lock once it has been released, and (3) there is no lock in the horizontal direction, It is difficult to set the minimum acceleration that produces the seismic effect (4) It is difficult to return once it has moved horizontally (5) There is a risk of locking due to vertical springs (6) Vertical The lateral stiffness of the spring cannot be ignored relative to the horizontal spring, so it is difficult to estimate the settings and effects of the horizontal spring.

The present applicant has already filed the patent application No. 54-145419 for the purpose of overcoming the above-mentioned difficulties in the conventional mechanism.
He proposed a new invention called ``seismic isolation floor.''

That is, in this invention, in order to achieve the purpose, a pedestal on which equipment to be seismically isolated is mounted is provided with a sliding surface incorporating a friction material with a small coefficient of friction in the lower part of the pedestal. A pre-compressed horizontal spring and a damper are arranged between the opposite ends or the periphery of the stand and the peripheral wall of the stand frame, and a horizontal spring and a damper are installed on the stand frame. The cover is firmly attached to cover the sliding surface of the stand, and this cover and the stand frame or stand are sandwiched with a gap to prevent locking. It featured a seismic isolation floor with a configuration that made it useful as a base.

It has been confirmed that this already proposed seismic isolation floor achieves its intended purpose, but in order to increase the seismic isolation effect, it is necessary to reduce the spring constant. However, in the case of compression springs, buckling occurs when the spring constant is reduced, and buckling is also likely to occur when the spring is displaced obliquely to the cylindrical axis of the compression spring, so it is not possible to increase the seismic isolation effect. It turns out that there is a problem that it cannot be done.

SUMMARY OF THE INVENTION Therefore, the present invention aims to obtain an improved seismic isolation floor that is capable of overcoming the above-mentioned difficulties in conventional mechanisms and at the same time solving the above-mentioned problems in already proposed structures. Its purpose is to

In order to achieve this objective, the present invention provides a horizontal platform which is placed horizontally so as to be easily movable on a fixedly arranged horizontal platform, and a seismically isolated structure is placed on top of the platform. In addition, a tension spring should be installed between the platform frame and the pedestal to prevent the pedestal from moving in the opposite direction to the direction of movement when the pedestal moves relative to the frame due to the action of earthquake force, etc. The end of the tension spring in the direction is immovable to the platform, but
It is characterized in that the end of the spring in the direction of movement is moved by the cradle and is arranged in such a way that the tension spring is stretched, so that a restoring force is exerted on the cradle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. 1 to 8 of the accompanying drawings showing embodiments thereof.

First, FIGS. 1 and 2 show an embodiment of the base isolation floor according to the present invention that is effective for unidirectional movement. In the figures, 1 is, for example, a rectangular horizontal platform, on which A pedestal 2, which has a planar shape similar to that of the platform 1 but has smaller dimensions, is placed horizontally.

This pedestal 2 is one on which equipment to be seismically isolated is fixed, and this pedestal 2 is horizontally mounted on the pedestal frame 1 via a low-friction element 3 provided on the bottom surface of the pedestal 2. It is placed.

In this embodiment, it is assumed that the seismic isolation effect occurs only with respect to the movement of the pedestal 2 in the long side direction.

In this case, as the low-friction element, a bar made of a suitable synthetic resin material is used. Alternatively, the former uses rollers or balls, and the latter uses rollers or a ball receiving plate, and similarly, it easily rolls in the long side direction. Configure or configure it so that it can be used.

In addition, a vertical wall 5 of a certain height is provided around the platform frame 1 so as to surround the platform 2 at an appropriate interval, and furthermore, from the upper side of this vertical wall 5 inwardly. A collar 6 having an appropriate width is extended horizontally, and the inner periphery of the collar 6 overlaps the upper periphery of the pedestal 2 with a slight gap, so as to cover the outer periphery of the pedestal 2. .

In this way, the platform frame 1, the vertical wall 5, and the collar 6 form a dust-proof case that substantially seals the platform 2.

The pedestal 2 also has a pair of opposite short sides so as to surround a part of each of the other pair of opposite long sides adjacent to each short side. Spring connection jig 1
Further, the vertical wall 5 and the spring connection jig 10 facing it are placed in a position corresponding to the position of the pedestal 2 during normal operation, and a rope, chain, etc. is pulled to a certain length. They are connected by a pair of stopper jigs 13 having an appropriate configuration that do not resist when pulled over a certain length but do not resist when compressed, and one spring connection is used. When the jig 10 is moved in the direction of the opposite vertical wall 5 against the action of the tension spring 11, the other spring connecting jig 10 is moved in that direction by means of the stop jig 13 connected thereto. It is designed to prevent

In addition, each spring connection jig 10 and the vertical wall 5 facing it
If necessary, these may be connected by a plurality of dampers 14.

In this way, in the present invention, when the pedestal 2 moves relative to the pedestal frame 1 in the long side direction due to an action such as an earthquake, the spring connection jig 10 in the movement direction
, whereas the spring connection jigs 10 in the opposite direction cannot be moved by the stop jigs 13, so the horizontal tension coil springs 11 connected at each end to these spring connection jigs 10 are expands.

Therefore, the pedestal 2 is given a restoring force by these extended tension coil springs 11.

In this case, the spring constant must be set in advance so that the natural frequency of the horizontal spring system is smaller than the frequency of the external force.

Further, by applying a tensile load to the horizontal spring 11 in advance using a length adjustment jig 12 such as a turn buckle, it is possible to set the minimum acceleration at which the pedestal 2 starts responding to an input.

In this case, the smaller the gap between the pedestal 2 in a stationary state and the spring connection jig 10, the more the pedestal 2 will start to move from the acceleration according to the set preload.

Now, to explain this with reference to figures, for example, in Fig. 3, the horizontal axis represents the displacement X, and the vertical axis represents the load P, respectively. Assuming that the KA static friction force is "frN" and the total mass of the upper part of the low friction element 3 is m ('d), the pedestal 2 will not move unless input acceleration AOX (gal) is applied.

Actually, the spring constant of each spring 11 in FIGS. 1 and 2 is K/2 (N/m), and the total mass of the upper part of the low friction element 3 is m
(Assuming KO, the static friction force on the real side in advance is Ffr
(N), the pre-tension length of the horizontal spring 11 to keep the pedestal 2 stationary with respect to the frame 1 until the input acceleration in the longitudinal direction of one spring is 100 (gal). m
What if? can get.

That is, it can be seen that it is better to tension each spring by δ (mm) in advance.

In this case, a damper 14 is installed between the pedestal 2 and the pedestal frame 1.
By arranging , damping force can be applied when the damping force of the horizontal spring system is smaller than necessary.

In this way, the embodiments shown in Figs. 1 and 2 have a seismic isolation effect only in the long side direction of the pedestal 2, but the embodiments shown in Figs. Figure 3 illustrates another embodiment of the invention useful for translational and rotational motion.

In the figure, the platform frame 1 and the pedestal 2 are shown as having square contours in this embodiment, and
The spring connection jig has four approximately L-shaped cross sections in each corner of the pedestal 2.
jigs 10, to 104, and the opposite ends of each jig are connected to horizontal tension coil springs 1, respectively.
1 along each side.

Note that each spring connection jig 10 to 104 has its corner portion connected to the opposing vertical wall 5 when the pedestal 2 is in the normal position.
are connected to each corner by a fastening jig 13 similar to that shown in FIGS. 1 and 2.

In this embodiment, as in the embodiments shown in FIGS. 1 and 2, when the pedestal 2 moves due to the action of an earthquake force or the like, the tension coil spring 11 corresponding to the direction of movement is stretched. In FIGS. 4 and 5, by way of example, the pedestal 2 is shown moved to the right as viewed in the figures.

As can be seen from this figure, the spring connecting jig 1 03, 1 0, which is in the opposite direction to this direction of movement, is the stop jig 1.
3 prevents its movement, this jig 1
The end of the tension spring 11 connected to the spring connection jig 10 remains in the same position, but the other end of the tension coil spring 11 is in that direction.

, 102 to provide restoring force to the frame 2.

Note that the related tension springs 11 are stretched not only in the direction of such seismic force but also in other horizontal directions, and therefore, in this embodiment, translation and rotation of the pedestal 2 are prevented. It can be seen that restoring force is effectively applied to both movements.

Further, FIGS. 6 and 7 show, as another embodiment of the present invention,
4 sets υ in the embodiment shown in FIGS. 4 and 5) Three of the tension coil springs 11 are connected to one wire member 2 such as a rope.
0, and pulleys 211 to 214 are attached to the outer corners of each spring connection jig 101 to 104, and the wire member 20 is connected to the remaining set of coil springs 11 through these pulleys, and the spring 11 and The filament member 20 forms one loop.

In this way, this embodiment can perform the same function as the embodiment shown in FIGS. 4 and 5.

It is obvious that the same effect can also be obtained by replacing the three tension coil springs 11 with two or only one wire member and forming a similar loop.

Although not shown in FIGS. 4 to 7, in the embodiments shown in these figures, as in the case of the embodiments shown in FIGS. Of course, a damper can also be appropriately placed between the two.

Finally, FIG. 8 shows an example of a large-area base isolation floor to which the base isolation floor of the present invention is applied; this base isolation floor has the same configuration as the base isolation floor described above. It is constructed by supporting a large-area frame 32 with several seismic isolation units 30 and a low-friction material unit 31.

In this way, by applying the seismic isolation floor of the present invention, it is possible to easily create a large area seismic isolation floor.

In addition, here, as the low friction unit 31, for example,
It can be constructed by a platform supported by rollers on top of the platform.

Since the present invention has the above configuration and operation, the following effects can be obtained.

That is, (1) Provide seismic isolation effect in all horizontal directions○ (2) It has a restoring force against rotation and a seismic isolation effect.

(3) The preload can be set freely, that is, the minimum acceleration required to provide a seismic isolation effect can be easily set, and the preload can act as a stopper up to that minimum acceleration.

(4) After the seismic isolation floor exerts its seismic isolation effect and moves, it naturally returns to its normal state.

(5) It can be easily made into a unit.

(6) A large seismic isolation floor can be easily created by connecting multiple units.

etc.

Furthermore, compared to the previously proposed seismic isolation floor, since the present invention uses tension coil springs, it does not buckle and the spring constant can be reduced, thus improving the seismic isolation effect. An excellent effect can be obtained in that the size can be increased.

[Brief explanation of the drawing]

Figures 1 and 2 are plan and cross-sectional views of a seismic isolation floor effective for unidirectional motion as an embodiment of the present invention, and Figure 3 shows the relationship between the preload of the tension spring, static friction force, and displacement. line diagram,
4 and 5 are a plan view and a sectional view of a seismic isolation floor effective for all translational and rotational movements on a plane as another embodiment of the present invention; FIGS. FIG. 8 is a side view of a large-area seismic isolation floor made using the seismic isolation floor of the present invention as a seismic isolation unit. 1...stand frame, 2...mount stand, 3...
...Low friction element, 10,101-104...
Spring connection jig, 11...Tension coil spring, 1
2... Length adjustment jig, 13... Stopping jig, 14... Damper, 20... Line member, 30...・Seismic isolation floor unit, 31...
・Low friction unit.

Claims (1)

[Scope of Claims] 1. A pedestal having a substantially rectangular planar profile is placed on a horizontal platform having a substantially rectangular planar profile which is fixedly arranged, and the bottom surface of the pedestal frame and the top surface of the pedestal are connected to the bottom surface of the pedestal frame, or By configuring one of the two sides with a low-friction material,
Alternatively, the equipment to be seismically isolated is fixed on this pedestal by placing rollers or balls between the two sides so that it can be easily moved, and the rectangular For a pedestal with a contour, a pair of spring connection jigs are placed on the pedestal frame so as to touch opposite sides of the pedestal, and opposite ends of the spring connection jigs are placed on the other opposite sides of the pedestal. Each spring connection jig and the frame are connected to each other by tension springs arranged along the line, and do not resist tension up to a certain length at a position corresponding to the position of the frame during normal operation. A seismic isolation floor characterized in that the seismic isolation floors are connected by means of fixing jigs such as ropes and chains that resist tension when pulled over a certain length but do not resist compression. 2 Claim 1 in which the tension spring is a coil spring
Seismic isolation floor as described in section. 3. The seismic isolation floor according to claim 2, in which each tension spring has a length adjustment jig such as a turn buckle incorporated therein. 4. A pedestal having a substantially rectangular planar profile is placed on a horizontal platform having a substantially rectangular planar profile that is fixedly arranged, and the bottom surface of the pedestal frame and the top surface of the pedestal, or either one of both By constructing with low friction material,
Alternatively, the equipment to be seismically isolated is fixed on this pedestal by placing rollers or balls between the two sides so that it can be easily moved, and the rectangular For a pedestal with a contour, a pair of spring connection jigs are placed on the pedestal frame so as to touch opposite sides of the pedestal, and opposite ends of the spring connection jigs are placed on the other opposite sides of the pedestal. Each spring connection jig and the frame are connected to each other by tension springs arranged along the line, and do not resist tension up to a certain length at a position corresponding to the position of the frame during normal operation. However, they are connected to each other using a stop jig such as a rope or chain that resists when pulled over a certain length but does not resist when compressed, and a damper is also placed between the pedestal and the platform frame. A seismic isolation floor characterized by: 5 Claim 4 in which the tension spring is a coil spring
Seismic isolation floor as described in section. 6. The seismic isolation floor according to claim 5, in which each tension spring has a length adjustment jig such as a turn buckle incorporated therein. 7. A pedestal having a substantially rectangular planar profile is placed on a horizontal platform having a substantially rectangular planar profile that is fixedly arranged, and the bottom surface of the pedestal frame and the top surface of the pedestal, or either one of both By constructing with low friction material,
Alternatively, by placing rollers or poles between both sides, the equipment can be placed so that it can easily move horizontally, and the equipment to be seismically isolated is fixed on this pedestal. For a pedestal having a planar profile of the shape, an L-shaped spring connection jig is placed on the pedestal frame at each corner thereof, and an opposite end of each jig is placed along each side of the pedestal. They are connected to each other by tension springs, and the corners of each spring connection jig and each corner of the frame are connected to each other by a tension spring at a position corresponding to the position of the stand during normal operation. A seismic isolation floor characterized by being connected to each other by fixing jigs such as ropes and chains that do not provide resistance but do not resist when pulled over a certain length and do not resist when compressed. 8 Claim 7 in which the tension spring is a coil spring
Seismic isolation floor as described in section. 9. A seismic isolation floor according to claim 8, in which each tension spring is provided with a length adjustment jig such as a turn buckle. 10 A pedestal having a substantially rectangular planar profile is placed on a horizontal platform having a substantially rectangular planar profile that is fixedly arranged, and the bottom surface of the pedestal frame and the top surface of the pedestal, or either one of both By constructing with low friction material,
Alternatively, by placing rollers or balls between both sides, the equipment can be placed so that it can easily move horizontally, and the equipment to be seismically isolated is fixed on this pedestal, and a rectangular For a pedestal having a planar profile of the shape, an L-shaped spring connection jig is placed on the pedestal frame at each corner thereof, and an opposite end of each jig is placed along each side of the pedestal. They are connected to each other by tension springs, and the corners of each spring connection jig and each corner of the frame are connected to each other by a tension spring at a position corresponding to the position of the stand during normal operation. They are connected by means of fixing jigs such as ropes or chains that do not resist, but do resist when pulled over a certain length and do not resist when compressed, and in addition, a damper is installed between the pedestal and the platform frame. A seismic isolation floor characterized by being arranged. 11. The seismic isolation floor according to claim 10, wherein the tension spring is a coil spring. 12. The seismic isolation floor according to claim 11, wherein each tension spring has a length adjustment jig such as a turn buckle incorporated therein. 13 A pedestal with a substantially rectangular planar profile is placed on a horizontal platform with a substantially rectangular planar profile that is fixedly arranged, and the bottom surface of the pedestal frame and the top surface of the pedestal, or either of both sides are Placed so that it can be easily moved by constructing it with a low-friction material or by arranging rollers or balls between both sides,
The equipment to be seismically isolated is fixed on this pedestal, and the pedestal with a rectangular outline has L
A letter-shaped spring connection jig is placed on the stand frame, a pulley is attached to the outer corner of each spring connection jig, and each pulley is held together by a wire member with a tension spring interposed in a part. The corners of each spring connection jig and the joints of the frame are connected to each other to form two loops, and the corners of each spring connection jig and each joint of the frame are pulled to a certain length at a position corresponding to the normal position of the frame. A seismic isolation floor is characterized in that the base isolation floor is connected to each other by means of fixing jigs such as ropes and chains that do not resist when pulled over a certain length, but do not resist when compressed. 14 A pedestal having a substantially rectangular planar profile is placed on a horizontal platform having a substantially rectangular planar profile which is fixedly arranged, and the bottom surface of the pedestal frame and the top surface of the pedestal, or either one of both By constructing with low friction material,
Alternatively, by placing rollers or balls between both sides, the equipment can be placed so that it can easily move horizontally, and the equipment to be seismically isolated is fixed on this pedestal, and a rectangular For a pedestal frame having a planar contour, an L-shaped spring connection jig is placed on the frame at each corner, a pulley is attached to the outside of each corner of each spring connection jig, and each pulley is attached to the frame. The wire members, in which a tension spring is partially inserted, are connected to each other to form one loop, and the corners of each spring connection jig and the stand frame are connected to each other at a position corresponding to the position of the stand during normal operation. A fixing jig, such as a rope or chain, that does not resist pulling up to a certain length, but resists pulling beyond a certain length, and does not resist compression, with each corner of the A seismic isolation floor characterized in that the base and the base frame are connected to each other, and a tamper is further arranged between the pedestal and the platform frame.