Deformable drum for the manufacture of tires

Claim 1

A DRUM FOR BUILDING AND SHAPING PNEUMATIC TIRES ADAPTED TO BE SELECTIVELY DISPOSED IN A CYLINDRICAL AND A TOROIDAL CONFIGURATION, THE SAID DRUM DOMPRISING A SHAFT, TWO CIRCULAR FLANGES SUPPORTED COAXIALLY IN SPACED RELATIONSHIP ON SAID SHAFT FOR RELATIVE AXIAL MOVEMENT, A FLEXIBLE TUBULAR MEMBRANE DISPOSED COAXIALLY OF SAID SHAFT AND EXTENDING BETWEEN SAID FLANGES, MEANS SECURING THE EDGES OF SAID MEMBRANE TO SAID FLANGES, A PLURALITY OF REINFORCING CABLES IN SAID MEMBRANE BETWEEN SAID SECURING MEANS, SAID CABLES EACH HAVING A LIMITED ELASTIC EXTENSIBILITY IN THE DIRECTION OF ITS LENGTH OF AN AMOUNT IN THE ORDER OF 10% OF ITS INITIAL LENGTH, AND MEANS FOR INTRODUCING AIR UNDER PRESSURE INTO THE REGION ENCLOSED BY SAID MEMBRANE AND FLANGES WHEN THE LATTER ARE MOVED TOWARD EACH OTHER TO THEREBY DISPOSE THE SAID MEMBRANE IN A TOROIDAL SHAPE WITH AN INCREASE IN THE LENGTH OF THE MEMBRANE BY AN AMOUNT DETERMINED BY THE EXTENT OF EXTENSIBILITY OF SAID CABLES.