LUEFTUNGSKLAPPE.

摘要

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 occurring, 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. The winch pulley (20) is of split construction and can be dismantled to enable the motor-gear drive unit to be removed whilst leaving the operating cable (76) in place. The gear drive mechanism holds the flap (11) locked in its closed position so long as the clutch (54) remains energised. The motor may be driven in reverse to allow the flap to open under the action of the springs (13) for normal day-to-day ventilation.