Patent ID: 7371161

Claim:
A heating, ventilation and air conditioning (HVAC) system comprising; a housing defining an air passage for directing air flow through said housing, a valve including a film defining an outer surface and a width with said outer surface extending across said width to distal terminal peripheries of said film defining opposing first and second peripheral edges of said film with said peripheral edges extending transverse to said outer surface to define a thickness of said film substantially transverse to said width and an opening disposed between said peripheral edges through said outer surface and supported by said housing to extend across said passage, a first sprocket rotatably supported by said housing for rotation about an axis and having teeth engaging said film for moving said film linearly, a second sprocket rotatable about said axis and having teeth engaging said film for moving said film linearly, a shaft extending transverse to said peripheral edges and defining said axis with said first sprocket coupled to one end of said shaft and said second sprocket coupled to an opposing end of said shaft, and said film defining recesses open to and disposed along each of said first and second peripheral edges with said teeth of said first sprocket extending into and out of said recesses of said first peripheral edge and said teeth of said second sprocket extending into and out of said recesses of said second peripheral edge such that said first and second peripheral edges of said film are captured entirely between said sprockets with said film being capable of floating relative to said sprockets while said sprockets maintain continuous engagement with said recesses for moving said film across said air passage relative to said sprockets.