The present invention relates to a retractable pin assembly for an injection mold. One end of the retractable pin is inside the mold, while the other end extends outside of the mold cavity. The inside end of the retractable pin may by shaped to conform with the shape and texture of the mold cavity wall....http://www.google.com.au/patents/US6379138?utm_source=gb-gplus-sharePatent US6379138 - Injection molding apparatus
