| 摘要 |
A nozzle ( 10 ) and gate ( 18 ) for a plastic injection mold ( 12 ) wherein the gate ( 18 ) has a primary sealing surface ( 50 ) located adjacent to the vestige ( 22 ) and a secondary sealing surface ( 54 ) located behind or inwardly of the primary sealing surface ( 50 ). The nozzle ( 10 ) has an insert retainer ( 42 ) threadably mounted therein to hold a tip or torpedo type insert ( 64 ). The insert retainer ( 42 ) has an outer annular primary seal ( 46 ) which engages the gate primary sealing surface ( 50 ), and an intermediate annular secondary seal ( 56 ) which engages the gate secondary sealing surface ( 54 ). The primary seal ( 46 ) prevents hot plastic from passing behind the nozzle and the secondary seal ( 56 ) ensures that even if some plastic gets behind the primary seal, it will not pass behind secondary seal ( 56 ) and contact heating coil ( 33 ). The main body portion may be shaped to form a third seal ( 80 ) for engagement with the secondary sealing surface ( 54 ) behind the position of the secondary seal ( 56 ).
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