Patent ID: 6959949

Claim:
Apparatus for electromagnetically preventing leaves of a multi-leaf revolving door from unintentionally swinging out of a normal operating position, each said leaf being fixed in a leaf frame which is pivotably mounted with respect to a door frame of the revolving door, said apparatus comprising a rotational direction independent locking mechanism for each said door leaf, each said locking mechanism comprising: a driving part which can be fixed to a respective said leaf frame, said driving part comprising a retaining pin upstanding from said leaf frame, a driven part which can be pivotably mounted to the door frame so that, in a starting position of said driven part, said driven part engages said driving part to fix the position of said door leaf frame in the normal operating position with respect to said door frame, said driven part comprising a fork arm which can be pivoted to engage and disengage said retaining pin, an electromagnetic brake which, when electrical current is supplied, generates a moment to retain said driven part in said starting position, and when electrical current is not supplied, allows said driven part to pivot from said starting position, said electromagnetic brake comprising a brake flange, a shaft rotatably mounted in said door frame, said fork arm and said brake flange being fixed to said shaft, a fork bracket fixed to said shaft for pivoting synchronously with said fork arm, and a switching mechanism which cooperates with the fork bracket to indicate the position of the leaf frame with respect to the door frame.