Spring assist system

A screen system comprising:

• a frame;
• a first support bracket and a second support bracket;
• a roller tube supporting a screen wound onto the roller tube, and mounted on the first support bracket and the second support bracket, and comprising a spring assist assembly comprising:
• a rigid tube having a proximal end and a distal end, wherein the proximal end is proximal with respect to the first support bracket when installed;
• a tube adapter with a proximal end and an outer tubular surface configured for insertion into a proximal end of the roller tube, and the proximal end of the tube adapter comprises a central aperture and one or more peripheral apertures located between the central aperture and the outer tubular surface;
• a torque shaft passing through the central aperture of the tube adapter and comprising a drive tool aperture at a proximal end, a shaft at a distal end, and a first mating surface;
• a linkage which rigidly connects the distal end of the torque shaft to the proximal end of the rigid tube;
• a helical spring located over the rigid
• tube;
• a proximal spring anchor;
• a distal spring anchor located over the rigid tube;
• a retainer which is rigidly attached to the tube adapter;
• a ratchet lock fitted over the shaft of the torque shaft comprising one or more proximal projections which extend through the one or more peripheral apertures in the tube adapter, one or more radial projections which are received in apertures in the retainer and a second mating surface,
• wherein
• the torque shaft, linkage and rigid tube are configured to rotate relative to the tube adapter and retainer, and the spring assist assembly is configured to allow relative rotation of the proximal spring anchor with respect to the distal spring anchor, and
• a ratchet mechanism is provided between the first mating surface of the torque shaft and the second mating surface of the ratchet lock such that when a tool is inserted into the drive tool aperture when the spring assist assembly is not mounted in the first and second support brackets, driving the tool drives relative rotation of the proximal spring anchor with respect to the distal spring anchor to tension the helical spring, and the ratchet lock is biased to engage with the torque shaft to retain added tension, and
• when the spring assist assembly is mounted in the first and second support brackets the proximal end of the roller tube is proximal to the first support bracket, the one or more proximal projections of the ratchet lock are displaced in a direction distal of the first support bracket to separate the first and second mating surfaces to release the ratchet mechanism to allow the spring tension in the helical spring to increase or decrease as the roller tube rotates with respect to the rigid tube.