Injection molding system with dynamic nozzle seal

An injection molding nozzle system comprising:

• a manifold;
• a melt-transfer bushing disposed within the manifold, the melt-transfer bushing defining a melt-transfer passage having an inlet end configured for receiving molten material from the manifold along a melt-receiving axis and an outlet end configured for discharging molten material along a melt discharge axis, the outlet end defining a melt discharge opening that defines an outlet center along the melt discharge axis when viewed in an axial direction;
• a nozzle having an inlet end for receiving molten material from the melt-transfer bushing and a discharge end for discharging the received molten material, a molten material passage extending along a nozzle passage axis and interconnecting the inlet end and the discharge end, the inlet end of the nozzle defining a nozzle center along the nozzle passage axis when viewed in the axial direction;
• and
• a collar configured for receiving the nozzle and for releasably coupling to the melt-transfer bushing;
• wherein:
• the melt-transfer bushing has an outwardly extending flange configured for engaging the manifold;
• the collar has an outwardly extending flange configured for engaging the manifold, a central opening through which the nozzle extends, and an inwardly extending flange configured for engaging the inlet end of the nozzle;
• and
• the releasable coupling of the collar to the melt-transfer bushing is with effect that:
• the inlet end of the nozzle is disposed in abutting contact with the outlet end of the melt-transfer bushing such that the inlet end of the nozzle is disposed in fluid communication with the melt-transfer passage;
• the outwardly extending flange of the melt-transfer bushing applies a first sealing force against a first side of the manifold in a first direction such that a first sealed interface is effected between the melt-transfer bushing and the first side of the manifold;
• the outwardly extending flange of the collar applies a second sealing force against a second, opposite side of the manifold in a second direction such that a second sealed interface is effected between the collar and the second side of the manifold, wherein the second direction is opposite to the first direction;
• and
• relative movement between the nozzle and the melt-transfer bushing in response to thermal expansion of the manifold is permitted.