Speed reducer for retractable screen systems

A retractable screen mechanism for covering an opening, the retractable screen mechanism comprising:

• two tracks mounted on opposing sides of the opening,
• a screen comprising a screen material mounted on a frame having two flexible opposing sides corresponding to and adapted to engage the two tracks,
• a spool mechanism extending between the flexible opposing sides and engaging a third side of the frame, the screen being adapted to wind up on the spool mechanism, the spool mechanism being biased to the wind up position,
• a latch mechanism mounted to a fourth side of frame opposite the third side, the fourth side extending between the two flexible opposing sides, the latch mechanism engaging a corresponding latching mechanism mounted on the corresponding side of the opening to latch the screen in an extended position,
• the spool mechanism having a speed reducer comprising a resistance structure moving through a viscous fluid to reduce the speed of the biased screen when moving to the wing up position, the spool mechanism comprising an elongated housing having a U-shaped profile and a rotating axle contained therein and a plate partially covering the open side end of the elongated housing, the elongated housing and the plate defining a slot, the third side of the screen extending through the slot to engage the axle, the axle engaging a spring mechanism at one end thereof, the spring mechanism being biased to hold the screen in the wind up position, the speed reducer being mounted at the other end of the axle.