Apparatus and system for a concealed screen assembly

A screen system for use with a sliding sash of a window to screen an opening as the sliding sash is opened, the system comprising:

• a longitudinally extending tube with a first end and a second end, the tube further comprising an interior channel, an outer diameter and a plurality of keyways extending longitudinally along the inner diameter;
• a spring with a first and second end, the spring extending through the interior channel of the tube;
• a first end tube cap for the first end of the longitudinally extending tube, the first tube end cap comprising a hollow cylinder with a first end, a second end, an outer radius, an inner radius and at least one key disposed on the outer radius for engagement with at least one of the keyways of the tube, wherein the first end of the spring is secured to the second end of the end cap hollow cylinder and the first end of the hollow cylinder is mounted to a stop plate, the stop plate sized to cover the first end of the tube;
• a longitudinally extending cartridge housing wherein the longitudinally extending tube is disposed within the cartridge housing, the cartridge comprising a first end and a second end, a pair of oppositely disposed side walls, a third wall extending between the side walls with a longitudinally extending slot therein and a fourth unslotted wall disposed opposite the slotted wall and extending between the side walls;
• a first cartridge end cap for restraining the longitudinally extending tube in position within the cartridge housing, the end cap proximate the first end of the tube, the first cartridge end cap comprising a plate and a mounting rod extending perpendicularly outwardly from the plate, wherein the first cartridge end cap mounting rod is inserted into the hollow cylinder of the first tube end cap and the hollow cylinder is capable of freely rotating about the mounting rod;
• a second cartridge end cap disposed proximate the second end of the longitudinally extending tube, the second cartridge end cap comprising a plate and a mounting rod extending perpendicularly outwardly from the plate, wherein the second end of the spring is secured to a distal end of the mounting rod;
• and
• a mesh screen with a leading edge, a trailing edge and opposed side edges, the mesh screen of sufficient length and width to freely span and substantially cover the window opening when uncoiled, the mesh screen being wrapped around the longitudinally extending tube, the trailing edge of the mesh screen secured to the longitudinally extending tube and the leading edge routed through the longitudinally extending slot of the third wall of the cartridge housing for attachment to the rail of a window sash wherein the mesh screen can be unwound from the longitudinally extending tube as the sliding sash is opened, and wound back onto the tube as the sliding sash is closing.