CONTAINERS

摘要

A metal container has a bottom wall (2) and side wall (6) provided with a low relief pattern of shallow grooves (12) or creases to define outwardly convex panels (13). The grooves or creases have a depth between 0.3 and 3 % of the radius of the side wall which has a thickness between 3 and 30 % of the radius of grooves. A method and apparatus are described in which the pattern of grooves and panels is formed progressively by a pinch pressure imposed by a mandrel (30) inside the container body and an arcuate rail (24) provided with teeth (33) to define the grooves. Preferably the pinch pressure sets the cross-sectional shape of the groove pulling the panels to shape by elastic deformation.