Injection molding sealing collar with a central hot tip shaft

In a hot tip gated injection molding apparatus having a plurality of spaced gates, each gate extending centrally from a well in a cooled cavity insert to a respective cavity, a heated melt distribution manifold having a forward face mounted with an insulative air space extending between the forward face of the heated manifold and the cooled cavity insert, and a melt passage extending from a common inlet and branching in the manifold to a plurality of branches, each branch having a portion which extends forwardly to an outlet on the forward face of the manifold in alignment with one of the gates, the improvement wherein:

• a sealing and conductive member having a plurality of spaced ribs which connect an elongated central conductive hot tip shaft to a surrounding outer sealing collar portion is mounted between the heated manifold and the cooled cavity insert in alignment with each of the gates, the outer collar portion having a rear end, a forward end, and a central bore wherethrough melt from the melt passage flows around the hot tip shaft to the gate, the outer collar portion bridging the insulative air space between the heated manifold and the cooled cavity insert with the rear end of the collar portion abutting against the forward face of the heated manifold and the forward end of the collar portion being seated in the well in the cavity insert, the hot tip shaft having a rear end and a forward end, the rear end of the hot tip shaft extending rearwardly past the rear end of the collar portion through the outlet on the forward face of the manifold a predetermined distance into the forwardly extending portion of a respective one of the melt passage branches, the forward end of the hot tip shaft being pointed and extending forwardly past the forward end of the collar portion a predetermined distance into the well in the cavity insert in alignment with the gate.