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(11) | EP 0 314 201 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Improvements relating to ventilators |
(57) An opening flap ventilator for buildings has pneumatic opening springs (13) and electric
motor-gear drive mechanism (14) operable to close the ventilation flap (11). The mechanism
has an electrically energised clutch (54) interposed in the gear drive chain (24,
26, 28, 48, 46) (see Fig. 2). On de-energisation of the clutch (54), which may be
automatic in response to the detection of a fire condition occuring, the ventilation
flap (11) is automatically opened. The flap (11) is subsequently closed by operation
of the motor which drives a winch pulley (20) for winding in a single operating cable
(76) in opposite directions from a location between its ends. A fused fire prop is
provided to prop the flap (11) open in the event of a fire as a safety measure. |