Screen/diverter changing mechanism for extruders

A screen/diverter changing mechanism for an extruder of the type including an extruding cylinder with an outlet at the downstream end thereof and an extruding screw rotatably disposed in said cylinder and circumferentially formed with a feed flight member for forwarding a plasticized material through the outlet of the cylinder for extrusion through a screen located at the downstream end of the extruding cylinder, said screen/diverter changing mechanism comprising:

• (a) a retainer box fixed to the downstream end of the extruding cylinder, said retainer box internally defining a longitudinal flow passage for plasticized material and a transverse guide bore which is in communication with said longitudinal flow passage;
• (b) a die plate fixed to the downstream end of said retainer box, said die plate being provided with a plurality of extruding nozzles in communication with said longitudinal flow passage;
• (c) a slide body slidably received in said transverse guide bore, said slide body internally defining a transverse diverting port;
• (d) a screen unit detachably fitted in said slide body, said screen unit internally defining a longitudinal flow passage for plasticized material, said screen unit being provided with a screen mounted in said longitudinal flow passage and, downstream of said screen, a plurality of extruding nozzles;
• (e) a diverter unit detachably fitted in said slide body, said diverter unit internally defining a bent flow passage for diverting the flow of plasticized material from the extruder cylinder, the downstream end of said bent flow passage being in communication with said transverse diverting port in said slide body;
• and
• (f) a drive mechanism linked to said slide body for selectively positioning either the upstream end of said longitudinal flow passage in said screen unit or the upstream end of said bent flow passage in said diverter unit in communication with said longitudinal flow passage in said retainer box;
• (g) said retainer box and said slide body being sized and shaped so that, when said longitudinal flow passage in said screen unit is in communication with said longitudinal flow passage in said retainer box, the portion of said slide body containing said diverter unit projects outwardly of said retainer box, permitting removal of said diverter unit and its replacement with a second screen unit.