Patent ID: 6345976
Filing Date: 2002-02-12
Classification: B29C

Abstract:
An injection apparatus comprising:a heating cylinder having a front end and an internal diameter, said heating cylinder being provided with a heater surrounding the same; a front end member having a nozzle and arranged at said front end of said heating cylinder, said front end member further having a measuring chamber formed therein at an internal central location thereof, said measuring chamber having a predetermined length and an internal diameter which is reduced by 8 to 15% with respect to said internal diameter of said heating cylinder; a plasticating screw arranged in said heating cylinder in a freely rotating and reciprocating manner; and an injecting plunger connected to said screw in one body and having a conical front end, said plunger having a diameter almost equal to said internal diameter of said measuring chamber, thereby being insertable into said measuring chamber in a freely reciprocating manner, said injecting plunger being movable together with said plasticating screw from a plasticating position in said heating cylinder into said measuring chamber toward said nozzle over a distance of an injection stroke, wherein a gap between said internal diameter of said heating cylinder and said diameter of said plunger functions as a plastication-accelerating block around an external peripheral surface of said plunger, said plastication-accelerating block having a length longer than said injection stroke.