Patent ID: 8807294

Claim:
A brake release device ( 40 ) attached to a door machine, said door machine ( 1 ) comprises an axle ( 2 ), a brake device ( 10 ) for braking said axle ( 2 ), a brake release bar ( 20 ) provided at the outside of said door machine ( 1 ) for actuating said brake device ( 10 ) to release said axle ( 2 ), and a pull chain disc ( 31 ) for rotating said axle ( 2 ), wherein said brake release device ( 40 ) comprises: a ring plate ( 41 ) fixed on a lateral end face of said pull chain disc ( 31 ), a plurality of equally spaced openings ( 411 ) being formed along the entire circumference of said ring plate; a base plate ( 43 ) provided at the outside of said door machine ( 1 ), and having a horizontal guiding portion ( 431 ) at one end thereof; a passive plate ( 44 ) having a plurality of plug pins ( 441 ) corresponding to said openings ( 411 ) of said ring plate ( 41 ) being provided on one end face thereof, said passive plate being guided by said guiding portion ( 431 ) to move between a first position in which said plug pins ( 441 ) are separated from said openings ( 411 ), and a second position in which said plug pins ( 441 ) are inserted into corresponding openings ( 411 ); a guiding member ( 45 ) parallel to said axle ( 2 ) being disposed on said base plate ( 43 ), said guiding member ( 45 ) having an axial guiding hole ( 451 ); a sliding pin ( 46 ) mounted within said guiding hole ( 451 ) for sliding therein, one end of said sliding pin ( 46 ) corresponding to said brake release bar ( 20 ) and the other end of said sliding pin ( 46 ) being connected to said passive plate ( 44 ); a spring element ( 47 ) accommodated in said guiding hole ( 451 ), one end of said spring element ( 47 ) abutting against said guiding member ( 45 ) and the other end of said spring element ( 47 ) abutting against said sliding pin ( 46 ) to an effect that said sliding pin ( 46 ) is compressed by said spring element and tends to move toward said brake release bar ( 20 ); and a fusible link device ( 48 ) having one end provided at a predetermined position, and the other end connected with said sliding pin ( 46 ) through a connecting member ( 481 ) so as to resist the restoring force of said spring element ( 47 ), so that the sliding pin is maintained at a distance from said brake release bar ( 20 ), and said passive plate ( 44 ) is maintained at said first position; when the surrounding temperature exceeds the melting point of said fusible link device ( 48 ), said fusible link device ( 48 ) melts and said connecting member ( 481 ) connecting said sliding pin is released, and said sliding pin ( 46 ) slides toward said brake release bar ( 20 ) under the action of the restoring force of said spring element to impact against said brake release bar ( 20 ) so as to release said brake device ( 10 ), whereby said passive plate ( 44 ) is actuated to move to said second position.