Retrofittable insulating system for solar rooms

DETAILED DESCRIPTION To accomplish these and other objects, the insulation shade system of the present invention includes elongated channel tracks extruded from a very strong plastic material such as Lexan, which are adapted to be secured on the inner face of the glazing bars of a greenhouse-type solar room.
The tracks which separate adjacent glass bays have a double channel with each channel serving one side of one of the adjacent bays.
A roller carrying an insulating shade sheet is mounted at the top of the bay, and the edges of the sheet are corded with the cords captured within the channels of the tracks on each side.
The lower edge of the shade sheet carries a batten, the ends of which are connected to cables which extend downwardly from the battens through the channels to spring motors that are mounted adjacent the bottoms of the tracks on the sill of each bay.
The spring motors form part of a spring motor subassembly which is rather small and unobtrusive when mounted in place on the sill.
The roller that carries the shade sheet may be automatically or manually operated so as to place the shade sheet at the desired position.
The spring motors bias the shade to the fully drawn position, and the manual or automatic means for operating the shade sheet roller acts against the bias of the spring motors to partially or fully retract the shade sheet.
In a preferred embodiment, a spring is provided in the spring motor which produces a variable pull force on the shade material.
Preferably, the profile of this variable force is tailored to conform to the profile of the pull force actually required to retract the shade, so that no unnecessary strain is placed on the shade material and other components of the system.
Such a variable torque spring is tailored to the needs of a particular shade system, and is produced by intentionally deflecting the spring to varying degrees along its length so that the coil diameters vary from point to point.