| 摘要 |
1457212 Roof ventilator for heat and smoke J EBERSPACHER 17 Jan 1975 [18 Jan 1974] 2139/75 Heading A5A A venting apparatus for extracting heat and smoke from roofs comprises a frame for attachment to the roof around aperture 11 therein and having end walls 4, 5, side walls 12, 13, two cover members 1, 2, pivotally supported on swivel pins 3a and 3b on 4 and 5 so that the pivotal axis of each cover is laterally spaced from the vertical plane througth the centre of gravity of that cover so that the weight of end cover urges it .to move from its closed position to its open position, tension springs 7a, 7b attached to end walls 4, 5 and end parts 8, 9 of the covers and which are extended .on the covers moving to their open position and releasable locking means. 6 to keep the covers in their closed position, which on release allows the covers to open. The looking means 6 is actuated mechanically, pneumatically or automatically by a temperature responsive fusible element. The covers 1, 2 may form part of an electrical circuit to indicate when they are open. The tension springs 7a, 7b initially assist the opening of the covers but are then extended during the opening to control the rate of such opening. |
