| 摘要 |
<p>A mechanism for effecting opening and closing movement of a vent panel 15 for a roof-mounted smoke vent has an elongate channel-shaped base member 56 for attachment to, or forming a part of, a frame 10 for the vent panel 15. A parallelogram linkage 69,70 connects a support 73 to the base member 56 and a power drive assembly including a motor 60 and a lead screw 61 effects movement of a slider 63 along the length of the base member, the slider being connected by an operating arm 75 to the support 73 or to the parallelogram linkage 69, 70. The support 73 carries a connector 77 for the panel 15, the support being slidable along that panel as the mechanism is operated to cause a connected panel to effect hinging movement by varying the geometry of the parallelogram linkage.</p> |
