Injection-molding apparatus for making objects of two different resins

An injection-molding apparatus for forming objects of two different resins, said apparatus comprising:

• a nozzle extending along an axis and having a tubular and axially centered outer nozzle part forming an axially forwardly opening outlet and a tubular and axially centered inner nozzle part fixed axially behind said outer part and forming therewith an annular port immediately axially behind said outlet and formed with a central axially forwardly opening port axially fixed behind and surrounded by said annular port;
• respective plastifying means for feeding respective and different plastified synthetic resins under pressure to said ports;
• and
• an axially displaceable valve needle in said nozzle and snugly fittable in said central port, said needle being displaceable relative to both of said nozzle parts
• from a fully forward position extending axially forward through said central port past said inner nozzle part into engagement with said outer nozzle part at said outlet and blocking both of said ports,
• through a partially back position in and blocking only said central port,
• to a fully back position clear of both of said ports, whereby in said fully forward position no resin can enter said nozzle, in said partially back position resin can enter said nozzle only from said annular port, and in said fully back position resins can enter said nozzle through both of said ports.