Exhaust fan and anti-backdraft shutter assembly

Claim 1

In an exhaust fan assembly with anti-back draft shutters for use in ventilating a building structure, said assembly including: a. a casing having an air passageway therethrough and aligned intake and exhaust ports defining said passageway, said casing being mounted in and providing an opening through a wall of a building structure to be ventilated; b. an exhaust fan motor and attached fan blade operably mounted in said casing passageway with the motor adjacent said intake port and the fan blade adjacent said exhaust port; c. a pair of shutters each pivotably mounted on a substantially vertical axis in said casing passageway between said motor and said intake port, said shutters being movable between an open position allowing substantially free passage of air through said casing intake port, past said motor and out said casing exhaust port and a closed position wherein said shutters are in sealing relation to each other and said casing intake port preventing passage of air back through said casing in direction from said exhaust port to said intake port; the improvement wherein: A. each of said shutters is supported on its own pair of upper and lower parallel shutter support arms, said arms extending substantially horizontally outwardly from upper and lower vertically aligned edge corners of said shutter, respectively, and in substantially perpendicular relation to said shutter; B. Each of the upper and lower shutter support arms is provided with a perpendicularly and vertically extending shutter pivot finger, the upper and lower fingers related to the support arms of each shutter being substantially vertically aligned with each other; C. means is provided to pivotally mount such upper and lower pivot fingers of each of said shutters in adjacent relation to the upper and lower pivot fingers of the other of such shutters, respectively, in position so that the shutters can move between an open position wherein the shutters approach parallel relation with respect to each other with the motor in between them under the action of air being exhausted by said exhaust motor and fan and said closed position; and D. means is provided to normally bias said shutters to move from the open toward the closed position.