DEVICE FOR SMOKE WITHDRAWAL Russian patent published in 1999 - IPC

FIELD: fire-fighting equipment, in particular, devices for smoke withdrawal from building stories through apertures on wall of ventilating shaft. SUBSTANCE: device has reduced of load on driving electromagnet in the form of rod mounted on gate by means of bushing and bracket on which starting and supporting chamfers are made. Gate with its one wall rests through roller on holder, while the other, through roller on bracket. Operation of electromagnet is alleviated and operating reliability increased due to distribution of gate weight on holder and bracket. With voltage applied to electromagnet, holder with the help of roller moves along the guide and gate lowers. Under the action of gate weight roller moves over chamfers and rod executes motion inside bushing to press in axial direction holder and to assist the electromagnet to overcome friction forces and counteraction of return spring along the whole path of armature stroke. EFFECT: improved operating characteristics due to reduced load exerted on driving electromagnet. 2 dwg