US Patent 7207795 Injection molding nozzle tip

A series of injection molding nozzles, one series having a two-piece nozzle and the other series having a three-piece nozzle. The two-piece nozzles include an inner and an outer insert portions, and the three-piece nozzles include an inner insert, an outer insert and a retaining thermal ring portions. The nozzles in accordance with the embodiments of the present invention include one, or more novel feature and which include: an extended thermo-barrier, a thermo-barrier access gap, threaded engagements between the nozzle pieces and/or between the nozzle and the nozzle housing, as well as structure elements that enable an improved methods for the removal and/or replacement of the nozzles from their housing. In addition, different performance conditions are encouraged in the nozzle designs by use of different or same thermal conductivity and/or hardness type materials. For example, materials may be selected such that the individual nozzle pieces are all made of the same material, different materials or combinations thereof.