Extendable liner for pickup truck boxes

In a vehicle having a storage area with upstanding sides and open at one end, the improvement consisting of an extendable liner comprising:

• (a) a rigid liner having two upstanding, parallel, vertical sides and a floor extending between said sides, said liner being adapted to slide horizontally within said storage area;
• and
• (b) means for supporting and extending said liner from said open end of said storage area and supporting said liner in an extended position, said extending and supporting means comprising:
• (i) a first pair of roller tracks in parallel spaced relationship fixed relative to said storage area;
• (ii) a second pair of roller tracks fixed in parallel spaced relationship, each said second roller track being fixed to opposite outer vertical surfaces of said upstanding sides of said rigid liner;
• (iii) a pair of roller carriages having mounted thereon a plurality of rollers and adapted for rolling in said first and second roller tracks, each said roller carriage comprising a first vertical surface having mounted on the interior surface thereof a plurality of horizontally-spaced rollers adapted for rolling in said first roller tracks, and a second vertical surface vertically-spaced from said first vertical surface and having mounted thereon a plurality of rollers adapted for rolling in said second roller tracks.