JP2001193792A - Ball type base isolation stand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball type base isolation stand with a retainer, eliminating the possibility of a backlash of a ball and improving base isolation performance. SOLUTION: A cutout 51 is formed in a retainer 5' at the corner of a body 16 and fitting grooves 53 in holders 49 are fitted onto the side edge 52 of the cutout 51. The opposed faces of both holders 49 are provided with recesses 50 in which the ball 4 is fitted and spring receiving holes 55 in which a compression spring 54 is fitted. The body 16 and the holders 49 have engagement grooves 52b and steps 49b for preventing the looseness. The ball 4 elastically held between the holders 49 allows upper and lower bases to be relatively moved smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base isolation table using balls (steel balls).

[0002]

2. Description of the Related Art As one type of seismic isolation table (seismic isolation device), there is a type in which a ball is rotatably interposed between an upper and lower base to allow relative movement of the upper and lower bases in the horizontal direction.

In this type of ball type seismic isolation table, one or both of the ball support surfaces of the upper and lower bases are
It is formed in a concave surface whose depth becomes deeper toward the center, so that the upper and lower bases return to the original position while reciprocating.

The ball-type seismic isolation table has the advantage that the upper and lower bases can be relatively moved in any direction in plan view, so that the base can be seismically isolated with good responsiveness to shaking in any direction. In addition, since the upper and lower bases move relative to each other twice as far as the ball travels, a compact and high seismic isolation function can be obtained. For this reason, the upper and lower bases can be used for furniture such as an art display case. Suitable for shaking table.

[0005]

SUMMARY OF THE INVENTION In a ball-type seismic isolation table, it is necessary to maintain the relative position of each ball in order to move the upper and lower bases relative to each other accurately following the shaking of the earthquake. For that purpose, each ball may be held by a retainer so as to roll freely.

However, when the retainer is provided, if there is play between the retainer and the ball, the ball collides with the retainer every time the relative movement direction of the upper and lower bases changes, and acceleration ( (Negative acceleration) is generated, and the smooth movement of the upper and lower bases may be impaired, and the seismic isolation performance may be reduced.

[0007] It is an object of the present invention to provide a seismic isolation table that can retain a ball with a retainer without causing the above-mentioned problems.

[0008]

In order to achieve the above object, according to the present invention, an upper and lower base arranged so as to overlap each other in a plan view is provided between the upper and lower bases in order to relatively move the upper and lower bases in a horizontal direction. It is provided with a plurality of interposed balls and a retainer for maintaining a relative position of each of the balls, and at a portion of the retainer corresponding to each of the balls, the balls roll when the upper and lower bases move relative to each other. A ball holding portion for elastically holding the ball in an allowed state is provided.

According to the invention of claim 2, in claim 1,
Each ball holding portion of the retainer is formed in a hollow shape opened up and down by a single member made of a synthetic resin, and the ball holding portion is divided into a non-loop shape in a plan view by a vertically long slit. Accordingly, the ball is lightly held by the elasticity of the ball holding portion itself.

[0010] On the other hand, in the invention of claim 3, in claim 1, each ball holding portion of the retainer is composed of a pair of holding members for holding the ball immovably, and holding these balls between the balls. It is urged in the direction by an elastic body such as a spring.

[0011]

In any of the claims, since the ball is accommodated in the ball holding portion of the retainer in a state where the ball is allowed to roll, the retainer and the ball are completely integrated. Move relative to each other.

Therefore, the upper and lower bases can be smoothly moved relative to each other without causing any acceleration. As a result, the significance of the provision of the retainer, that is, the movement of each ball in a state where the balls are aligned, is eliminated. The significance of enhancing seismic performance can be assured.

According to the second aspect of the present invention, since the ball holding portion is formed of a single member, the structure is simplified accordingly. Further, since the ball holding portion can have a sturdy structure, it is suitable for a seismic isolation table on which a large load is applied.

According to the third aspect of the present invention, since the holding body is urged by the elastic body, the ball can be securely held by the holding body without increasing the dimensional accuracy of members such as the holding body. Can be.

[0015]

Next, an embodiment of the present invention will be described with reference to the drawings.

(1) First Embodiment (FIGS. 1 to 19) FIGS. 1 to 19 show a first embodiment, of which FIG. 1 is a schematic perspective view of the whole, and FIG. FIG. The seismic isolation table 1 of the present embodiment is designed to be used for an article (subject to be isolated) W having a considerable weight, such as a display case for an art object or a museum.

As shown in FIG. 2, the seismic isolation table 1 comprises an upper base 2 on which the seismic object W is mounted, and a lower base 3 placed on the floor.
And four balls 4 interposed between the upper and lower bases 2 and 3
And a retainer 5 for holding these balls 4. The retainer 5 is provided with a rotary damper 6 as an example of resistance applying means (damper means) for giving resistance to the relative movement of the upper and lower bases 2 and 3 so that the seismically isolated object W does not move with a light force. Hereinafter, each part will be described in detail.

[0018] FIG. 3 is a bottom view taken along the line III-III of FIG. 2, and FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3. As shown in both these figures and FIG. The upper substrate 7 is provided.

At four locations near the corners of the lower surface of the upper substrate 7, upper receiving plates 8 made of a metal plate are fixed by screws. On the lower surface of the upper receiving plate 8, a concave curved surface 8a having a circular shape when viewed from the bottom is formed. There is a space between the adjacent upper receiving plates 8, and therefore, on the lower surface of the upper base 2, upper grooves 7 a extending in four directions from the center are formed.

An upper frame 9 made of a metal plate protruding downward is fixed to the four circumferences of the upper substrate 7. A certain distance is also provided between the upper receiving plate 8 and the upper frame 9, and a stopper 10 having a substantially L-shaped cross section located inside the upper frame 9 is attached to the four sides of the upper substrate 7. I have.

The first lower surface of the upper base 2 has two first grooves 7a crossing in an L-shape.
The damper guide rail 11 and the first damper guide rail 12 are fixed. As shown in FIG. 5, the guide rails 11 and 12 for both dampers have a structure in which a resin member 14 made of a synthetic resin having a guide groove 13 is surrounded by a frame member 15 made of a metal plate. Of course, the metal plate may be used to form a simple U-shaped or C-shaped cross section, or the whole may be made of synthetic resin.

[0022] Structure of Retainer 5 Next, the retainer 5 will be described with reference to FIGS.
This will be described with reference to FIG. 6 is a plan view taken along line VI-VI of FIG. 2, FIG. 7 is a partial plan view of the retainer 5, and FIG.
FIG. 9 is a sectional view taken along line IX-IX of FIG. 6, and FIG.
FIG. 11 is a sectional view taken along line XX of FIG. 6, and FIG. 11 is a sectional view taken along line XI-XI of FIG.

The retainer 5 includes a main body 16 made of a metal plate formed in a substantially rectangular shape in a plan view, and a corner member 17 made of a synthetic resin fixed to four corners of the main body 16 by screws or the like. The ball 4 is fitted into a cylindrical ball holding portion 17 a integrally formed with the ball 17.

In this case, as clearly shown in FIGS. 7 and 8, a slit 21 located diagonally outside the retainer 5 is formed in each ball holding portion 17a so as to extend over the entire vertical direction. Thus, each ball holding unit 1
7a is cut into a discontinuous state, and the ball 4 is pinched very loosely by the elastic force of the ball holding portion 17a.
Is maintained in a state where there is no backlash and there is almost no frictional resistance.

As shown in FIGS. 9 to 11, each edge 16a of the main body 16 of the retainer 5 is formed by bending a downwardly opening gutter, and each edge 16a has a downwardly opened retainer. The side guide rail 18 is fixed.

An upper slider 20a of the runner 20 is movably fitted to the retainer-side guide rail 18 via a number of small balls 19. Although not shown, the small ball 19 is held by an intermediate rail so as not to fall off. The runner 20 includes a bracket plate 20b, and an upper slider 20a is screwed to an upper surface of the bracket plate 20b.

The outer end of the bracket plate 20b is bent in an upwardly stepped shape. When the bracket plate 20b abuts on the stopper 10 of the upper base 2, the maximum relative dynamic stroke of the upper and lower bases 2 and 3 is reduced. While being regulated, the seismic isolation object W is prevented from falling.

As shown in FIG. 9, a lower slider 20c is fixed to the lower surface of the bracket plate 20b of the runner 20, and this lower slider 20c is attached to a base-side guide rail 23 fixed to the lower base 3 by a number of small sliders. It is mounted via a ball 19.

The lower slider 20c is the upper slider 20a.
And extends in a direction orthogonal to the plan view. The runner-side guide rail 18 and the base-side guide rail 23 also extend in a direction orthogonal to the plan view.

[0030] Next, the rotary damper 6 will be described mainly with reference to FIGS.
1 will be described. As shown in FIGS. 8 to 11, the rotary damper 6 includes a case 25 having a circular shape in a plan view and opening upward, and a disk (resistance plate) housed inside the case 25.
26.

The case 25 is made of synthetic resin (or may be made of metal), and its upper surface is closed by a cover plate 27. As a means for giving resistance to the relative rotation between the case 25 and the disk 26, a viscous fluid 28 having a high viscosity such as silicone resin is filled in the case 25 (without using the viscous fluid 28). It is also possible to provide resistance by simple friction).

A flange 25a is formed in the case 25, and a rotating guide body 29 which is in close contact with the upper surface and the outer peripheral surface of the flange 25a is fixed to the main body 16 of the retainer 5 at appropriate intervals along the circumferential direction. I have. Therefore, the case 25 is rotatably attached to the retainer 5.

At the center of the disk 26, a boss 30 that projects upward from a hole formed in the cover plate 27 is fixed. A first arm 31 extending in the horizontal direction is fixed to the boss 30, and an upward pin 32 protrudes from the tip of the first arm 31. A second arm 33 that extends horizontally toward the outside of the case 25 is fixed to the cover plate 27 of the case 25, and an upward pin 34 projects from the tip of the second arm 33. The arms 31 and 33 extend to the edge of the main body 16.

The space between the case 25 and the lid 27 and the boss 3
A seal material 35 such as an O-ring is interposed between the cover plate 27 and the cover plate 27.

Then, the pin 32 of the first arm 31 is inserted into the guide groove 13 of the first damper guide rail 11 of the upper base 2, and the pin 34 of the second arm 33 is inserted into the second damper guide rail of the upper base 2. 12 guide grooves 1
3 is inserted.

[0036] Next, the structure of the lower base 3 will be described with reference to FIGS. 12 is a plan view taken along the line XII-XII of FIG. 2, FIG. 13 is a sectional view taken along the line XIII-XIII of FIG. 12, and FIG.
FIG.

As shown in these figures, the lower base 3 has a lower substrate 36 made of a metal plate, and the lower substrate 36 has four lower receiving plates 37 corresponding to the upper receiving plate 8 of the upper base 2. Is fixed. For this reason, the lower base 3 is formed with a lower groove 36a extending in a cross shape in plan view. A lower frame 38 is fixed to the periphery of the lower substrate 36. In addition,
The lower substrate 36 may receive the ball 4 directly.

The aforementioned base-side guide rails 23 are fixed to the respective lower grooves 36a of the lower substrate 36. Note that FIG. 13 shows an intermediate rail 39 that holds the small ball 19.

As shown in FIG. 14, a friction plate 40 which is in close contact with the main body 16 of the retainer 5 is disposed at the center of the lower substrate 36. The friction plate 40 also constitutes an example of the resistance applying means described in the claims, and is made of a material such as an ABS resin that generates an appropriate friction between the friction plate 40 and the retainer 5.

The friction plate 40 is screwed to a support plate 42 fixed to the upper end of the cylindrical body 41, and the support plate 42 is held by a screw 43 screwed into the lower substrate 36 so as not to be dislodged upward. A compression spring 44 is fitted inside the cylindrical body 41, and presses the friction plate 40 against the lower surface of the retainer 5 with an appropriate pressure.

[0041] Description of Movement Next, the movement of the seismic isolation table 1 will be described with reference to FIGS. FIG. 15 is a plan view of the seismic isolation table 1 with the upper base 2 omitted, and FIG. 16 is a cross-sectional view taken along the line XVI-XVI of FIG. 15 (parts below the arms 31 and 32 are omitted). 17 is a plan view showing an example of the movement, and FIG. 18 is a view showing XVIII-XVI in FIG.
19 is a plan view for explaining the movement of the rotary damper 6. FIG.

Each pair of the retainer-side guide rail 18 and the base-side guide rail 23 extends in a direction orthogonal to the plan view, and the runner 20 can freely move the two guide rails 18 and 23 without changing the plane posture. To slide,
The retainer 5 and the upper and lower bases 2 and 3 can relatively move in any direction. Therefore, no matter what direction the floor (ground) shakes due to the earthquake, the upper and lower bases 2 and 3 can move relative to each other in the same direction as the shake of the earthquake.

FIG. 17 shows a state in which the upper and lower bases 2 and 3 are relatively moved in the longitudinal direction of the first guide rail 11, and in this state, the first arm 31 does not change its posture and the first damper guides. The second arm 33 moves along the rail 11 and the second damper guide rail 12
As a result, a moment is exerted by the guide action of (1), so that it rotates horizontally as indicated by arrow A. For this reason, the case 25 of the rotary damper 6 and the disk 26 rotate relative to each other, and the resistance at that time imparts resistance to the relative movement of the upper and lower bases 2 and 3.

FIG. 19 schematically shows the relationship between the relative movement direction of the upper and lower bases 2 and 3 and the function of the rotary damper 6. When the upper and lower bases 2 and 3 relatively move in the X direction,
Contrary to the case of FIG. 17, only the first arm 31 rotates horizontally without changing the attitude of the second arm 33. Also,
When the upper and lower bases 2 and 3 relatively move in a direction inclined with respect to the side, both arms 31 and 33 rotate.

After all, the guide rails 11 and 12 for both dampers are used.
Extend in the direction crossed in plan view, the retainer 5
No matter which direction the upper base 2 moves relative to
The distance between the pins 32, 34 at 1, 33 changes. Therefore, the case 25 of the rotary damper 6 and the disk 26 rotate relative to each other, and opposition is given to the relative movement between the retainer 5 and the upper base 2. Since the relative movements of the upper and lower bases 2 and 3 are interlocked via the ball 4, eventually, resistance is also applied to the relative movement of the upper and lower bases 2 and 3.

Therefore, even if a force that pushes the seismic isolated object W in the horizontal direction is applied in normal times, the seismic isolated object W does not move with a light force. In addition, resonance is suppressed during an earthquake. Furthermore, even when an external force that horizontally turns the seismic isolated object W acts in a normal state, for example, when a person pushes the edge of the seismic isolated object W with a strong force in the horizontal direction, the seismic isolated object W remains horizontal. It does not turn, but simply moves in a straight line while maintaining a stable posture.

The ball holding portion 17 of the retainer 5
If the slit 21 is not provided in the ball holder 4, the ball 4 may not move due to the dimensional error of the corner member 17 or the ball 4.
There is a possibility that the backlash may occur in the area a or the ball 4 may be difficult to move.

When there is backlash, the ball 4 collides with the retainer 5 each time the direction changes when the upper and lower bases 2 and 3 move relative to each other, and the relative movement of the upper and lower bases 2 and 3 accelerates (minus the negative movement). Acceleration), and smooth relative movement may be impaired. Conversely, if the ball 4 is gripped tightly by the ball holding portion 17a, the ball 4 slips on the upper and lower bases 2 and 3 and the seismic isolation function is greatly reduced.

On the other hand, when the ball holding portion 17a is divided by the slit 21 as in the present embodiment, the ball holding portion 17a can be elastically deformed, so that the dimensional error of the ball 4 and the ball holding portion 17a can be absorbed. As a result, it is possible to hold the ball 4 in a state where there is no backlash (clearance) and the resistance is suppressed as much as possible. Therefore, generation of acceleration and generation of slip can be prevented or significantly suppressed, and the seismic isolation function can be significantly improved.

(2) Second Embodiment (FIGS. 20 to 27) FIGS. 20 to 27 show a second embodiment, in which FIG. 20 is a front view of a separated state, and FIG. The X
XI-XXI plan view, FIG. 22 is a plan view of a main part, FIG. 23 is a separated plan view of a main part, FIG. 24 is a separated perspective view of a main part, and FIG. 25 is an assembled state of XXV-XXV of FIG. FIG. 26 is a cross-sectional view, FIG. 26 is an XXVI-XXVI view of FIG. 21 in an assembled state, and FIG. 27 is a view showing an example of a use state.

This embodiment is applied to a very small seismic isolation base 1 ', and comprises an upper base 2', a lower base 3 'and a retainer 5', but the guide means as in the first embodiment. And no dampers.

As shown in FIG. 20, the upper base 2 'has a structure in which a metal upper receiving plate 8 is fixed to an upper frame 46, and the upper receiving plate 8 has a concave curved surface 8a. On the other hand, the lower base 3 'has a structure in which a flat receiving plate 37 is fixed to a lower frame 47, and the lower receiving plate 37 is provided at a position near four sides of the lower receiving plate 37 for carrying the seismic isolation table 1'. A keyhole-shaped hole 48 for inserting a tool (not shown) is provided.

The upper frame 46 and the lower frame 47 may be made of plywood or resin. Further, a decorative cloth may be provided on the outer surfaces of the upper and lower bases 2 and 3 '.

The retainer 5 'has a plate-shaped main body 16 with four corners cut, and a pair of holding bodies 49 each serving as a ball holding portion are arranged at the four corners. Also, the main body 1
A stopper 10 projecting in both the vertical direction of the main body 16 is screwed to the four sides of 6. The main body 16 is made of a synthetic resin (may be made of another material such as a metal plate).

For example, as shown in FIGS. 23 and 24, a concave portion 50 in which the ball 4 is partially fitted is formed at the distal end portion of each of the holding members 49. The recess 50 has a plurality of flat surfaces so as to make point contact with the ball 4 at a plurality of points.

At the four corners of the main body 16, the two holding members 4
A notch 51 into which about the rear half of 9 is fitted is formed, while a fitting groove 53 that fits into the left and right side edges 52 of the notch 51 is formed on the outer side surfaces of both holding bodies 49. Also,
A spring receiving hole 55 into which the compression coil spring 54 fits is formed on the opposing surfaces of the rear portions of the left and right holding members 49.

A semicircular fulcrum 52a in a plan view is formed at the tip of the left and right inner edge 54 of the notch 51 in the main body 16, while the front end of the fitting groove 53 in both the holding members 49 is The circular arc portion 5 so as to fit tightly with the fulcrum portion 52a
3a.

An engaging groove 54 b is formed at the rear end of the left and right inner edge 54 of the notch 51 in the main body 16, while a rear part of the fitting groove 53 of the two holding members 49 is
A step 53b that fits into the engagement groove 54b is formed.

As can be easily understood from the figure, the holding members 49 are supported by the fulcrum portions 52a of the main body 16 from the outside and the rear portions are urged by the springs 54 so as to be separated from each other. Numeral 4 is elastically held by both holding bodies 49. For this reason, the ball 4 is held in a state where there is no backlash, and the posture of both holding bodies 49 is also held. Needless to say, the spring 54 is set to an appropriate spring force that allows the ball 4 to roll. It is preferable that the holding members 49 be made of a material having a friction coefficient as small as possible.

In this embodiment, since members such as pins and screws are unnecessary, the number of members can be reduced accordingly. Also,
In a state where the ball 4 and the spring 54 are sandwiched between the holding members 49, the fitting groove 53 can be fitted in the side edge 52 of the notch in a one-touch manner, while the holding members 49 are fingers. When the finger is pinched and moved close to the spring 54 to release the engagement between the stepped portion 53b and the engagement groove 54b, it can be removed with one touch. Therefore, attachment / detachment is extremely simple.

As shown in FIG. 26, the retainer 5 '
Of the frame 4 in the upper and lower bases 2 ', 3'
6 and 47, the upper and lower bases 2 ',
3 'relative movement stroke is regulated.

The base isolation table 1 'of this embodiment can be used independently by itself, or as shown in FIG.
The display case W is supported by the base isolation table 1 shown in the first embodiment, and the display surface of the display case W is provided on the base 1 ′ of the present embodiment.
It is also possible to use it together with another seismic isolation table, as in the case of placing the exhibit W 'in this manner. As described above, when used in combination with another seismic isolation table 1, the seismic isolation function can be further improved because the seismic isolation function can be further improved (this is the same in the third and fourth embodiments).

(3) Third Embodiment (FIGS. 28 to 31) FIGS. 28 to 31 show a third embodiment.
Is a plan view of the retainer 5 ', and FIG. 29 is XXIX-XXIX of FIG.
FIG. 30 is an isolated front view, FIG. 31 is a XXXI of FIG.
It is -XXXI sectional view.

In this embodiment, overhanging portions 49a and 49b are formed in the middle of a pair of holding members 49, and are attached to the main body 16 by pins (bolts) 56 at the portions of the overhanging portions 49a and 49b. ing.

In this embodiment, the spring receiver 55 'has a pin shape. In addition, the posture of both holding bodies 49 is maintained by applying a downward step 49 ′ formed at the tip end of one of the holding bodies 49 to the end face of the main body 16. One of the holding members 49 is used as the posture holding means.
May be fixed to the main body 16 with a pin, the pin 56 may be non-rotatably fitted to the main body 16 and one of the holding members 49, and the other holding member 49 may be rotatably fitted to the pin 49. .

(4) Fourth Embodiment (FIGS. 32 to 33) FIGS. 32 and 32 show a fourth embodiment, and FIGS.
2 is a plan view, and FIG. 33 is a sectional view taken along the line XXXIII-XXXIII of FIG.

In this embodiment, the two holding members 49 are attached to the main body 16 at their intermediate portions by separate pins (bolts) 56 so as to be horizontally rotatable. At the rear ends of both holding bodies 49, spring hooks 49c and 49d overlapping each other are formed. One end of a tension spring 57 arranged to extend in a diagonal direction of the main body 16 is engaged with the spring hooks 49b. Stopped.

The other end of the tension spring 57 is locked to the intermediate member 58, and the intermediate member 58 is fixed to the main body 16 by a bolt 60 penetrating a bracket 59 fixed to the main body 16.
Can be moved in the diagonal direction. As shown in FIG. 33, the main body 16 has an escape hole 61 for exposing the ball 4 downward.

In this example, the holding members 49 are urged by the tension springs 57 so as to hold the ball 4, and the posture is maintained. Further, by rotating the bolt 60 to move the intermediate member 58, the ball 4
Can be adjusted.

(5) Others The present invention can be variously embodied in addition to the above embodiment.
For example, when the holding body is provided, it is not limited to the rotary type, but may be slidably attached to the main body so as to approach and separate as a whole, and may be biased by a spring in the approaching direction.

Further, a receiving portion for supporting the ball from one side is integrally formed with the main body, and a rotating or sliding pressing body is attached to the main body, and the fixed receiving portion and the movable pressing body are used to hold the ball. It is also possible to pinch. Furthermore, it is also possible to make the main body of the retainer made of synthetic resin and to integrally form the holding portion at each corner of the main body.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an entire seismic isolation table according to a first embodiment.

FIG. 2 is a front view of a separated state.

FIG. 3 is a bottom view taken along the line III-III of FIG. 2;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a partially enlarged view of FIG. 4;

FIG. 6 is a plan view taken along the line VI-VI of FIG. 2;

FIG. 7 is a partial plan view of a retainer.

8 is a sectional view taken along line VIII-VIII of FIG.

FIG. 9 is a sectional view taken along line IX-IX of FIG. 6;

FIG. 10 is a sectional view taken along line XX of FIG. 6;

11 is a sectional view taken along line XI-XI in FIG.

FIG. 12 is a plan view taken along the line XII-XII of FIG. 2.

13 is a sectional view taken along the line XIII-XIII of FIG.

14 is a sectional view taken along the line XIV-XIV in FIG.

FIG. 15 is a plan view in a state where an upper base is omitted.

16 is a sectional view taken along the line XVI-XVI in FIG.

FIG. 17 is a diagram illustrating an example of an operation state.

18 is a sectional view taken along line XVIII-XVIII in FIG.

FIG. 19 is a diagram for explaining movement.

FIG. 20 is a front view of the separated state of the second embodiment.

21 is a plan view as viewed from XXI-XXI in FIG. 20.

FIG. 22 is a plan view of a main part.

FIG. 23 is an isolated plan view of a main part.

FIG. 24 is an exploded perspective view of a main part.

25 is a sectional view taken along the line XXV-XXV of FIG. 21 in an assembled state.

26 is an XXVI-XXVI view of FIG. 21 in an assembled state.

FIG. 27 is a diagram illustrating an example of a use state.

FIG. 28 is a plan view of a retainer according to a third embodiment.

FIG. 29 is a front view taken along XXIX-XXIX of FIG. 28.

FIG. 30 is a plan view of a separated state.

31 is a sectional view taken along the line XXXI-XXXI of FIG. 28.

FIG. 32 is a plan view of a retainer according to a fourth embodiment.

33 is a sectional view taken along the line XXXIII-XXXIII in FIG. 32.

[Brief description of reference numerals]

 W Seismic-isolated object 1, 1 'Seismic isolation base 2, 2' Upper base 3, 3 'Lower base 4 Ball 5, 5' Retainer 16 Main body of retainer 17 Corner member 17a Ball holding part 49 Clamping body 50 Depression 54, 57 spring

Claims (3)

[Claims] An upper and lower base arranged so as to overlap in a plan view, a plurality of balls interposed between the upper and lower bases for horizontally moving the upper and lower bases, and maintaining the relative positions of the respective balls. A ball holding portion for elastically holding the ball in a state where the ball is allowed to roll when the upper and lower bases move relative to each other, at a location corresponding to each ball in the retainer. There is a ball-type seismic isolation table. 2. Each of the ball holding portions of the retainer is formed in a hollow shape opened vertically by a single member made of a synthetic resin. By dividing into shapes,
The ball type seismic isolation table according to claim 1, wherein the ball is lightly held by the elasticity of the ball holding portion itself. 3. Each of the ball holding portions of the retainer includes a pair of holding members for holding the ball so that the ball cannot be pulled out. The holding member is urged by an elastic body such as a spring in the direction of holding the ball. The ball-type seismic isolation table according to claim 1.