Movable partition structure

Claim 1

IN A MOVABLE PARTITION STRUCTURE, THE COMBINATION COMPRISING MEANS DEFINING A HORIZONTAL SURFACE, SAID SURFACE HAVING A TRACK THEREIN COMPRISING A SLOT WITH A RELATIVELY NARROW VERTICAL LEG AND AN ENLARGED CROSS LEG SPACED BELOW THE SURFACE, A THIN UPRIGHT PANEL HAVING A RELATIVELY NARROW LOWER EDGE ADAPTED TO SLIDINGLY ENGAGE THE HORIZONTAL SURFACE, AND RIGID MEANS FIXED ON THE LOWER EDGE OF SAID PANEL EXTENDING DOWNWARDLY THROUGH THE VERTICAL LEG OF THE TRACK AND HAVING AN ENLARGED PORTION FIXED ON THE LOWER END THEREOF EXTENDING INTO THE ENLARGED LEG OF THE TRACK, THE LENGTH OF SAID ENLARGED PORTION ALONG SAID TRACK BEING AT LEAST AS GREAT AS THE THICKNESS OF SAID PANEL, SAID RIGID MEANS COMPRISING THE SOLE MEANS FOR GUIDING AND LOCKING THE PANEL RELATIVE TO SAID SURFACE, THE DISTANCE BETWEEN THE ENLARGED PORTION AND THE LOWER EDGE OF THE THIN PANEL BEING SUCH THAT THE PANEL WHEN IN UPRIGHT POSITION MAY BE READILY SLID ALONG THE HORIZONTAL SURFACE AND A SLIGHT DEVIATION OF THE PANEL FROM ITS UPRIGHT POSITION CAUSES SAID ENLARGED PORTION TO ROCK WITH THE PANEL ABOUT A TRANSVERSE AXIS AND ENGAGE THE PORTIONS OF THE TRACK DEFINING THE ENLARGED LEG OF THE TRACK TO LOCK THE PANEL IN POSITION LONGITUDINALLY OF THE TRACK.