Knock-down cardboard shelf structure

Claim 1

IN A KNOCK-DOWN CARDBOARD SHELF STRUCTURE, A PANEL SHAPED TO DEFINE AN UPRIGHT REAR WALL HAVING LATERAL EDGES, SIDE WALL PANELS HINGED TO SAID REAR WALL ALONG SAID LATERAL EDGES AND ADJUSTABLE BETWEEN COLLAPSED POSITIONS SUBSTANTIALLY IN THE PLANE OF THE REAR WALL AND SET-UP POSITIONS EXTENDING FORWARDLY THEREFROM, AT LEAST ONE SHELF PANEL HAVING A REAR EDGE AND END EDGES AND ADAPTED TO DEFINE A SHELF PROJECTING FORWARDLY FROM THE REAR WALL AND IN HINGED RELATION THERETO ALONG ITS REAR EDGE, LATERAL ATTACHMENT PLEATS HINGED TO THE END EDGES OF THE SHELF PANEL, EACH PLEAT BEING COMPOSED OF HINGEDLY CONNECTED SECTIONS THE REAR ONE OF WHICH IS SECURED FLATWISE TO THE ADJACENT SIDE WALL PANEL, THE SECTIONS OF EACH PLEAT BEING HINGED TOGETHER ALONG A LINE PASSING THROUGH THE POINT OF INTERSECTION OF THE SHELF HINGE LINE AND THE ADJACENT LATERAL EDGE OF THE REAR WALL, WHEREBY MOVEMENT OF THE SIDE WALL PANELS FROM COLLAPSED TO SET-UP POSITIONS OPENS SAID PLEATS TO SWING THE SHELF PANEL FORWARDLY, A HINGE FORMED IN SAID REAR WALL ALONG A LINE TRANSVERSE TO SAID LATERAL EDGES, SAID HINGE EXTENDING ACROSS SAID EDGES AND SIDE WALL PANELS SO THAT WHEN THE SIDE WALL PANELS ARE IN THEIR COLLAPSED POSITIONS THE SECTIONS OF THE STRUCTURE ON OPPOSITE SIDES OF SAID LAST-MENTIONED HINGE CAN BE FOLDED INTO SUPERPOSED RELATION.