Manufacturing rotation symmetrical molded article with undercuts, slots, cavities or threading on inside, by placing removable splay sleeve inside article and then drawing it inside mold

摘要

A radially expandable sleeve splayable by an awl is placed inside the article, the outer contours of the sleeve in the splayed state corresponding to the desired inner contours of the article. Once the sleeve has been splayed the article is drawn inside a mold whose inner contours correspond to the desired outer contours of the article, and the awn is removed from the sleeve in its length direction so that the sleeve returns to its non-splayed state and can be removed from the article using an ejector. An Independent claim is also included for the splay tool.