Method and apparatus for the manufacture of threaded aluminum containers

Abstract

Deep drawn, deep drawn and stretched, or extruded cylindrical aluminium containers are varnished internally and externally, provided with a twostage neck by drawing in and onto the neck is rolled a thread, followed by cutting to length. The drawing-in of the neck, thread rolling and cutting to size are performed with the same container setting. To improve the flexibility, adhesiveness and sliding characteristics, the varnish used is mixed with catalysts, plasticizers and/or lubricants. When the thread is rolled, the container neck is supported from the inside with a quasi-stationary screw-pitch gauge, while from the outside a thread roll is rolled over the neck surface and presses the thread inwards into the neck. The screw-pitch gauge and the thread roll are forcibly guided in such a way that a slip occurs between them and the neck material. As a result the varnish also remains intact in the vicinity of the thread.

Dependencies are inferred from the claim text.