| 摘要 |
A vent cover for vehicles equipped with roof vents is raisable and lowerable from within the vehicle by rotating a crank. The cover includes a dome formed by a top wall, sidewalls that depend from the top wall, and a venturi cone member secured to an underside of the top wall. A vent base mounted to the roof of the vehicle has upstanding sidewalls so that air molecules exiting the vehicle must flow upwardly to pass over the top of the sidewalls and then downwardly to enter the atmosphere external to the vehicle. The air molecules are forced to flow downwardly after they have passed over the top of the vent base sidewalls by the sidewalls that depend from the top wall of the dome. The cooperative shape of the venturi cone member, the walls that depend from the top wall of the dome, and the upstanding sidewalls of the vent base creates a constricted area above the upstanding sidewalls where upwardly flowing air molecules must change their path of travel to flow downwardly. The constriction forces the air molecules to flow at a high rate of speed, creating a venturi effect that efficiently pulls stale air, smoke, fumes, and the like out of the vehicle. |
