Closure structure

Claim 1

IN A DISPLAY-TYPE, REFRIGERATED FOOD CABINET HAVING AN ACCESS OPENING COMMUNICATING WITH ATMOSPHERE, CURTAIN STRUCTURE FOR SUBSTANTIALLY COVERING SAID ACCESS OPENING, COMPRISING: MOISTUREPROOF AND RESILIENTLY FLEXBILE SHEET MEANS HAVING FIRST AND SECOND, SPACED AND OPPOSITE EDGES, SAID SHEET MEANS BEING PRESTRESSED SO THAT IT WILL ROLL UPON ITSELF AROUND AN AXIAL SUBSTANTIALLY PARALLEL WITH SAID FIRST EDGE, SAID STRESS BEING SUCH THAT SAID STRUCTURE IS SELF-SUPPORTING IN A TIGHTLY ROLLED POSITION WHEN SAID STRUCTURE IS SUSPENDED FROM SAID FIRST EDGE THEREOF, SAID SHEET MEANS HAVING A PLURALITY OF RELATIVELY SMALL AND SPACED OPENINGS THERETHROUGH, WHEREBY SMALL AMOUNTS OF AIR CAN MOVE FROM THE BOUNDARY LAYER OF AIR ON ONE SIDE OF THE SHEET TO THE BOUNDARY LAYER OF AIR ON THE OPPOSITE SIDE OF THE SHEET; MEANS FOR ATTACHING THE FIRST EDGE OF SAID SHEET MEANS TO SAID CABINET NEAR ONE EDGE OF SAID ACCESS OPENING, WHEREBY SAID POSITION OF SAID STRUCTURE IS NEAR SAID ONE EDGE OF SAID OPENING, THE DISTANCE BETWEEN SAID FIRST AND SECOND EDGES OF SAID SHEET MEANS BEING GREATER THAN THE DISTANCE BETWEEN SAID ONE EDGE AND THE OPPOSITE EDGE OF SAID ACCESS OPENING; FIRST ENGAGING MEANS ON SAID CABINET NEAR THE OTHER EDGE OF SAID ACCESS OPENING; AND SECOND ENGAGING MEANS CONNECTED TO SAID SHEET MEANS NEAR ITS SECOND EDGE AND ENGAGEABLE WITH SAID FIRST ENGAGING MEANS ON SAID CABINET FOR RELEASABLY HOLDING SAID SECOND EDGE OF SAID SHEET MEANS AGAINST MOVEMENT WITH RESPECT TO SAID CABINET AND THEREBY PREVENTING SAID SHEET MEANS FROM ROLLING UPON ITSELF.