Injection molding apparatus having degating and sprue removal means

In an injection molding apparatus including two juxtapositionable side molds including cooperating means for forming a sprue and gates communicating with open-ended article-forming cavities;

• juxtapositionable bottom and top mold elements, at least one of said top and bottom mold elements being displaceable vertically relative to the other and including means for closing the open-ended article-forming cavities;
• means operatively connecting said side molds and bottom and top mold elements for moving them simultaneously and in unison and causing the side molds to be spaced laterally at a vertical parting line therebetween when the top mold element is raised vertically from said bottom mold element, the improvement comprising:
• automatic article degating means and sprue-removingmeans including bottom pins on said bottom mold element projecting into the article-forming cavities at the parting line for conforming to a surface of the articles being molded and supporting the molded articles thereon when the side molds are moved apart at the vertical parting line;
• sorue-removing means
• sprue-pulling means of said bottom mold element comprising a sprue-holding rod projecting from the bottom mold element at the vertical parting line and including an upper portion projecting into the sprue, said sprue-holding rod including means for receiving on the portion projecting into the sprue molding material therein so that the sprue of the articles and the molded articles are integrally connected by the gate;
• top pins and top members depending from said top molded element at the vertical parting line into said article-forming cavities for movement with the top mold element relative to the bottom mold element and side molds upon upward relative movement of said top mold element;
• and
• stripper means on said bottom mold element and including means for moving the stripper means relative to the bottom pins and sprue-holding rod when the side molds are apart at the vertical parting line when the sprue and the molded articles are exposed between the side molds;
• said top pins comprising automatic degating means including means for receiving mold material therein for automatic degating of the molded articles from the sprue prior to the sprue being separated from the sprue-holding rod, said sprue-holding rod being displaceably mounted in said bottom mold element and having limited relative movement with respect to said bottom mold element, said top pins and sprue-holding rod having means affording a timing sequence between article-degating and sprue-removal whereby initial upward movement of said top mold element degates the articles from the sprue retained on the sprue-holding rod, and the stripper means subsequently strips the sprue from the sprue-holding rod after the side molds are spaced at the vertical parting line.