JPS6453832A - Tire forming drum - Google Patents

Abstract

PURPOSE:To obtain the surface of a drum, which maintains uniform flatness without any recess and projection, by a method wherein a step, produced between a small diametral center ring and large diametral rings on both side, is absorbed and eliminated by a rubber ring, covering the whole of the upper surface of all rings along them without remaining any gap. CONSTITUTION:Steps, produced between a small diametral center ring 3 and large diametral both side rings 1, 2 are absorbed and eliminated by a rubber band 5, covering the whole of the upper surfaces of all rings 1, 2, 3 along them. The surface of a drum, which maintains uniform flatness without any recess and projection, may be obtained in such a manner. According to this method, the laminating bonding of carcass materials in a primary forming work may be effected very easily. The rubber band 5 is very intimate with the carcass materials and the operation of bonding may be effected smoothly and easily. When a secondary forming work is effected by deforming a carcass tire into a troidal shape, respective comb type inner ends 6, 7 of both side rings 1, 2 are engaged mutually. According to this method, the flatness of the inner surface of the tire may be secured with good workability.