Injection molding nozzle with edge gate inserts and sealing ring

摘要

Edge gated injection molding apparatus wherein each heated nozzle has the combination of a circular sealing ring extending around it and several gate inserts, each extending radially outward from the nozzle in alignment with a gate. The sealing ring bridges an insulative air space between the heated nozzle and the surrounding wall of a well in the cooled mold to provide a sealed portion of the space around the gate inserts. The outer end of each gate insert is spaced a predetermined distance "D" from the wall of the well in which the nozzle is seated to form an opening therebetween. The opening is large enough to allow pressurized melt to flow outwardly therethrough into the sealed front portion of the space between the nozzle and the surrounding wall of the well and small enough to prevent the partially solidified melt in the sealed front portion of the space being sucked back into the melt stream during subsequent injection cycles.