| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of a fire by leak by falling a short-circuit ball when occurrence of an earthquake of a prescribed seismic intensity is detected, and brining the ball into contact with electrodes arranged below it, or pressing and short-circuiting them by the ball to instantaneously interrupt the current. SOLUTION: A necessary number of conductive metal short-circuit balls 3 are arranged on a placing frame 2 arranged in the upper canter of a box body 1. Both lateral sides of the placing frame 2 are formed of inclined surfaces 4 having a gradient such that short-circuit balls 3 can jump over it at a prescribed seismic intensity (for example, a little under 5.0). When the seismic intensity is small, the short-circuit balls 3 are not fallen, but when the seismic intensity is the prescribed value (a little under 5.0) or more to arise a possibility of building breakdown, the short-circuit balls 3 are jumped over the inclined surfaces 4 and fallen to the space between both electrodes 10 through a funnel- like guide part 9 and make contact with the electrodes 10 to carry an overcurrent between the electrodes 10. Thus, since the power source is short- circuited, and a circuit breaker arranged within a building is operated to immediately interrupt the current, occurrence of a fire by leak can be prevented. |
