Mfr. of hollow ball

摘要

The rotationally symmetrical hollow body, such as a sports ball for soccer or rugby, is formed by a single curved strip of a pliable material which is wound in an even spiral in the form of the final shape. The edges of the strip are joined flush with each other along the curvature of the winding. Also claimed is a process where an appts. positions the needles according to the final shape and to give a steady procession of the bonding action along the edges of the strip material. The ball is rotated through the centre of the spiral winding or the poles of the ball shape.