Speed reducer for retractable screen systems

摘要

A retractable screen mechanism having two tracks mounted on opposing sides of an opening and a screen with a screen material mounted on a frame having two flexible opposing sides corresponding to and adapted to engage the two tracks. A spool mechanism for winding up the screen extends between the flexible opposing sides and engages a third side of the frame and is biased to a wind up position. The spool mechanism has a speed reducer which comprises a resistance structure moving through a viscous fluid to reduce the speed of the biased screen when moving to the wind up position.