Seismic isolation device

1. A seismic isolation device, comprising:

a sliding platform ( 100 ) having a sliding surface ( 120 ) of a downwardly concave shape provided on an upper surface thereof; and

a sliding body ( 200 ) placed on the sliding surface ( 120 ), having a bottom surface of a downwardly convex shape to correspond to the sliding surface ( 120 ), the sliding body being capable of sliding on the sliding surface ( 120 ) in all directions by means of a sliding means including a plurality of sliding balls ( 222 ),

wherein the sliding body ( 200 ) slides on the sliding surface ( 120 ) and absorbs vibrations due to an earthquake,

wherein a motion-limiting hole ( 140 ) is provided in the center of the sliding surface ( 120 ), and a motion-limiting protrusion ( 260 ) that corresponds to the motion-limiting hole ( 140 ) is provided on the bottom surface of the sliding body ( 200 ), whereby the motion-limiting protrusion ( 260 ) is prevented from deviating from the motion-limiting hole ( 140 ), thereby allowing the sliding body ( 200 ) to be maintained on the sliding platform ( 100 ) without being slipped off therefrom.

2. The seismic isolation device of claim 1 , wherein a collapse-preventing plate ( 262 ) is provided on a lower end of the motion-limiting protrusion ( 260 ), and a collapse-preventing plate chamber ( 270 ) is provided in the motion-limiting hole ( 140 ), the collapse-preventing plate chamber ( 270 ) being configured to have a space receiving the collapse-preventing plate chamber ( 270 ) without being slipped off therefrom, thereby allowing the sliding body ( 200 ) to be maintained on the sliding platform ( 100 ) without being slipped off therefrom.

3. The seismic isolation device of claim 1 , wherein an inspection hole ( 160 ) extending from an external surface of the sliding platform ( 100 ) to the motion-limiting hole ( 140 ) is provided, thereby enabling an inside of the motion-limiting hole ( 140 ) to be inspected externally.

4. The seismic isolation device of claim 1 , wherein the sliding balls ( 222 ) are embedded in the bottom surface of the sliding body ( 200 ) in a state that each of the sliding balls ( 222 ) is partially exposed externally.

5. The seismic isolation device of claim 4 , wherein the each of the sliding balls ( 222 ) is received in a housing ( 225 ) provided concavely on the bottom surface of the sliding body ( 200 ), and auxiliary balls ( 223 ) are provided inside the housing ( 225 ) and rolled in contact with an associated sliding ball ( 222 ), thereby reducing friction.

6. The seismic isolation device of claim 1 , wherein the sliding means is a system consisting of multiple ball transfer units ( 220 ) each having one of the sliding balls ( 222 ) and is embedded in the bottom surface of the sliding body ( 200 ), and each of the ball transfer units ( 220 ) is supported by an elastic plate ( 230 ).

7. The seismic isolation device of claim 1 , wherein the sliding means is installed on a plate-shaped cage ( 228 ), so as to allow the sliding balls ( 222 ) to be rotatably movable.

8. The seismic isolation device of claim 1 , further comprising at least one auxiliary sliding body ( 250 ) disposed between the sliding platform ( 100 ) and the sliding body ( 200 ),

wherein the auxiliary sliding body ( 250 ) is supported by the sliding means and is capable of sliding on the sliding surface ( 120 ) that is concaved, having a concave sliding surface on the upper surface thereof, thereby allowing the sliding body ( 200 ) to be seated and slide thereon.

9. The seismic isolation device of claim 1 , further comprising an elastic spacer ( 300 ) provided on the bottom of the sliding platform ( 100 ), to elastically support the sliding platform ( 100 ), thereby absorbing vibrations.

10. The seismic isolation device of claim 9 , further comprising a supporter ( 400 ) that supports the elastic spacer ( 300 ),

wherein the sliding platform ( 100 ) is coupled by bolts ( 500 ) to the supporter ( 400 ), placing the elastic spacer ( 300 ) between the sliding platform ( 100 ) and the supporter ( 400 ), and the bolts ( 500 ) are vertically movable, causing the sliding platform ( 100 ) to be movable vertically according to contraction and expansion of the elastic spacer ( 300 ).

11. The seismic isolation device of claim 1 , further comprising a structure supporter ( 600 ) provided above the sliding body ( 200 ), to support a structure,

wherein on the structure supporter ( 600 ), a pivot ( 640 ) having a pivot ball body ( 642 ) of a spherical shape on a lower end thereof is protruded downwardly, and a pivot ball cup ( 242 ) that receives the pivot ball body ( 642 ) therein is provided in the upper surface of the sliding body ( 200 ), and

the structure supporter ( 600 ) is rotatably movable in the sliding body ( 200 ) as the pivot ball body ( 642 ) is received in the pivot ball cup ( 242 ).

12. The seismic isolation device of claim 11 , wherein an-auxiliary balls ( 643 ) are provided inside the axial hole pivot ball cup ( 242 ) and rolled in contact with the pivot ball body ( 642 ) sliding ball ( 222 ), thereby reducing friction.

13. The seismic isolation device of claim 11 , wherein the pivot ball cup ( 242 ) is provided in an embedded bearing housing ( 240 ) which is embedded on the upper surface of the sliding body ( 200 ), causing the pivot ball cup ( 242 ) to be formed on the upper surface of the sliding body ( 200 ), and the embedded bearing ( 240 ) is supported by the elastic plate ( 230 ).

14. The seismic isolation device of claim 1 , further comprising a protective cover ( 700 ) inside of which the sliding platform ( 100 ) and the sliding body ( 200 ) are received, to protect the sliding platform ( 100 ) and the sliding body ( 200 ),

wherein the protective cover ( 700 ) is configured to be flexible and extendible so as to absorb vibrations.

15. A seismic isolation device, comprising:

a sliding platform ( 100 ) having a sliding surface ( 120 ) of a downwardly concave shape provided on an upper surface thereof, and

a sliding body ( 200 ) placed on the sliding surface ( 120 ), having a bottom surface of a downwardly convex shape to correspond to the sliding surface ( 120 ), the sliding body being capable of sliding on the sliding surface ( 120 ) in all directions by means of a sliding means including a plurality of sliding balls ( 222 ),

wherein the sliding body ( 200 ) slides on the sliding surface ( 120 ) and absorbs vibrations due to an earthquake,

further comprising a ball joint ( 280 ) having a lower end thereof rotatably held to the sliding platform ( 100 ) and an upper end thereof rotatably held to the sliding body ( 200 ), between the sliding platform ( 100 ) and the sliding body ( 200 ), wherein the ball joint ( 280 ) comprises a joint body ( 281 ) having a predetermined length and joint balls ( 282 ) formed at an upper end and a lower end of the joint body ( 281 ), respectively, and the joint balls ( 282 ) are fitted to holes formed in the sliding body ( 200 ) and the sliding platform ( 100 ), respectively, thereby preventing the sliding body ( 200 ) from slipping off from the sliding platform ( 100 ).

16. A seismic isolation device, comprising:

a sliding platform ( 100 ) having a sliding surface ( 120 ) of a downwardly concave shape provided on an upper surface thereof, and

a sliding body ( 200 ) placed on the sliding surface ( 120 ), having a bottom surface of a downwardly convex shape to correspond to the sliding surface ( 120 ), the sliding body being capable of sliding on the sliding surface ( 120 ) in all directions by means of a sliding means including a plurality of sliding balls ( 222 ),

wherein the sliding body ( 200 ) slides on the sliding surface ( 120 ) and absorbs vibrations due to an earthquake,

wherein a collapse-preventing ring ( 290 ) having a lower end thereof held to an outer circumference of the sliding platform ( 100 ) and an upper end thereof held to an outer circumference of the sliding body ( 200 ) is provided,

a locking hole ( 202 ) is provided to a predetermined depth along an outer circumference of the sliding body ( 200 ), and a locking protrusion ( 292 ) protruded toward the locking hole ( 202 ) is provided on an upper end of the collapse-preventing ring ( 290 ),

wherein the locking protrusion ( 292 ) is engaged with the locking hole ( 202 ), thereby allowing the sliding body ( 200 ) to be movable and preventing the sliding body ( 200 ) from slipping off from the sliding platform ( 100 ).