Injection molding nozzle insert with valve member locating blades

In a valve gated injection molding apparatus to convey melt to a gate extending through a mold to a cavity comprising a heated nozzle having an outer surface, a rear end, a front end, a melt bore extending longitudinally therethrough from the rear end to the front end, and a seat extending around the melt bore at the front end, the nozzle seated in a well having an inner surface in the mold with an insulative air space extending between the outer surface of the nozzle and the inner surface of the well in the mold, an elongated valve member having a cylindrical outer surface mounted to extend centrally in the melt bore through the nozzle, and valve member actuating means connected to the valve member whereby the valve member is reciprocated between an open position wherein the melt flows through the gate from the melt bore into the cavity and a closed position wherein the gate is sealed off by the valve member, the improvement comprising;

• a valve member locating insert having an outer collar and at least one spiral blade having a front and a rear end, the at least one spiral blade extending a predetermined distance inwardly from the outer collar to a curved inner surface, the outer collar being received in the seat at the front end of the nozzle and the valve member extending centrally through the locating insert with the curved inner surface of the at least one spiral blade encircling the value member sufficiently to locate and maintain the valve member in accurate alignment with the gate as the valve member reciprocates and melt flows around the valve member and through the locating insert past the at least one spiral blade the at least one spiral blade tapering to sharp edges at the front and rear ends.