RUNNER CONSTRUCTION CAPABLE OF MOLDING MANY PIECES IN INJECTION MOLD

摘要

PURPOSE:To prevent resin pressure at the front part of a runner from falling and resin to be filled in a terminal cavity from shortage by arranging retrogressively in the runner a runner switching pin which stops the resin to flow in the runner or lets it pass through the runner. CONSTITUTION:A sliding hole 6 is made in the vertical direction of the runner 2, the retrogressive runner switching pin 3 is inserted by resin pressure into this sliding hole 6, this pin 3 is energized by a spring etc. from the lower part and the runner 2 is shut by this pin 3. If resin is injected from a sprue 5, since the runner 2 is closed by a pin 3a in the middle, the resin flows into cavities A-D to increase the resin pressure. When the resin pressure exceeds the energizing force of the spring, the pin 3a retrogresses, the runner 2 opens and new resin flows into E-H. Since new resin is supplied in sequence, the resin hardens in the middle of a runner and the resin pressure does not fall.