device for loading and priming, as well as the withdrawal of smoke and heat.

摘要

The roof vent operating mechanism constructed so that a choice of opening positions is available and the operating mechanism does not obstruct the clear height of the space underneath. The mechanism consists of frame (1) which projects above the roof level and flap (2) fitted in frame (3) hinged to the frame (1) by joints (3a). On the inside of frame (1) crossbar (4) has swivelling arm (6) fitted with fulcrum (5). The arm (6) is fitted with guide (7a) carrying arresting device (7b) which is disconnectable by pin (7) mounted on frame (3). The arm (6) is connected with the crossbar (4) by a disconnectable blocking device (8). Between the arm (6) and the crossbar (4) is a thrust sleeve (9) acting on the fulcrum (10) of the crossbar and/or fulcrum (11) of the arm (6).