| CPC H01H 39/00 (2013.01) [H01H 9/30 (2013.01); H01H 9/52 (2013.01)] | 7 Claims | 

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               1. An electric circuit breaker device comprising: 
            an igniter provided on a housing; 
                a projectile disposed in an accommodating space, the accommodating space being formed in the housing and extending in one direction, the projectile being configured to be projected along the accommodating space by energy received from the igniter; 
                a conductor piece provided on housing and forming portion of an electric circuit, the conductor piece including a cutoff portion disposed crossing the accommodating space and configured to be cut off by the projectile; and 
                an arc-extinguishing region that is provided in the accommodating space and in which a coolant material is disposed, the arc-extinguishing region being configured to receive the cutoff portion after being cut off, wherein 
                the projectile includes 
                a first projectile configured to cut off the cutoff portion from the conductor piece by being projected by the energy received from the igniter, and 
                a second projectile configured to press, into the arc-extinguishing region, the cutoff portion cut off by the first projectile. 
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