Patent ID: 7293805

Claim:
A central release device ( 1 ) for a safety door which can be used to close the door automatically when power is disrupted, comprising: a cord ( 10 ), of which one end is a passive end ( 10 a ) and the other end is an active end having potential energy; a outer casing ( 30 ) defining an internal space ( 31 ), in which a base plate ( 32 ) is attached to one side of the casing ( 30 ) and an electromagnet ( 33 ) is attached on an opposite side, the electromagnet ( 33 ) being switched on in normal circumstances; a pair of crank arms ( 34 ) pivoted on the base plate ( 32 ) of which one end of each arm forms a grip ( 34 a ) and the other end of each arm ( 34 b ) is connected to a linkage bar ( 35 ); a sliding bar ( 36 ) wedged between the electromagnet ( 33 ) and the linkage bar ( 35 ) of which one end of the sliding bar ( 36 a ) is connected to the linkage bar ( 35 ), and the sliding bar ( 36 ) being provided with a spring ( 37 ) enabling the grip ( 34 a ) of arms ( 34 ) to incline to a release position, and the other end ( 36 b ) of the sliding bar ( 36 ) being connected to a retracted plate ( 38 ), retracted on the electromagnet ( 33 ) when the electromagnet ( 33 ) is switched on such that the grip ( 34 a ) of the crank arms ( 34 ) remains in a clamped position; and an intermediate piece ( 20 ) of which one end is tied to the passive end ( 10 a ) of the cord ( 10 ) and the other end is clamped onto the grip ( 34 a ) of the crank arms ( 34 ).