Downdraft range ventilator

A ventilator for drawing off cooking effluents produced at a cooking unit positioned in a generally horizontal surface, the ventilator comprising:

• a housing suitable for mounting beneath the surface in which the cooking unit is positioned;
• a vent member having an opening through which the cooking effluents may be drawn off, said vent member being movable in a generally vertical direction between a retracted position in which said vent member lies below the surface and an extended position in which the vent extends above the surface adjacent to the cooking unit, said vent member being in fluid communication with said housing, at least when said vent member is in the extended position;
• a blower coupled to said housing for drawing the cooking effluents into said opening in said vent member, downwardly through said vent member into said housing, and discharging same from said ventilator;
• and
• means for moving said vent member between the retracted and extended positions, said means having;
• follower means mounted on said vent member and having a planar follower surface lying generally normal to the direction of vertical movement of said vent member;
• rotary motive power means;
• and
• drive means coupled to, and movable by, said motive power means, said drive means having a roller engaging said follower surface and displaceable therealong, said roller being moved by said motive power means in an arcuate path in a plane generally parallel to the direction of movement of said vent member between said extended and retracted positions so as to have a vertical component of motion, displacement of said roller along said follower surface upon movement of said drive means driving said vent member upwardly to the extended position as a result of the component of vertical motion of said roller, the engagement of said follower surface and said roller further being such that the force moving said vent member to the retracted position is that of the weight of said vent member and that the roller restrains the downward movement of said vent member to the retracted position as a result of its vertical motion component.