Screw conveyor-type delivery and mixing device for plastics injecting molding machine

A screw conveyor type delivery and mixing device for use with a plastics injection molding machine, comprising;

• a delivery tube having a material feeding opening at a first end for receiving raw plastic material;
• a large central screw rod;
• a plurality of small side screw rods rotationally engaged with said large central screw rod;
• said large central screw rod and said small side screw rods being housed in said delivery tube;
• said large central screw rod and said small side screw rods having sections along a longitudinal length thereof, each consecutive section of said sections having different corresponding threads and pitches;
• said large central screw rod and said plurality of small side screw rods each having an engagement end permitting said central screw rod to oppositely rotate said small side screw rods when said large central screw rod is rotated by an external power;
• said threads of said central screw rod being in mesh with said threads of said small screw rods at each of said sections;
• said delivery tube having a large central tubular portion corresponding to said large central screw rod and a plurality of small tubular portions respectively corresponding to said small side screw rods;
• said large central tubular portion communicating with each said small tubular portion along a full axial length thereof;
• a heating means in operational association with said delivery tube at said selected sections of said large central screw rod and said small sides screw rods so as to keep said sections working at a desired temperatures;
• after said engagement end, said large central screw rod and said two small side screw rods being engaged together at an engagement section, and having a blank section, a coarsely threaded feeding section with large pitches, a blank section, a finely threaded squeezing section with small pitches, a blank section, and a mediumly threaded buffer section with medium pitches, a blank section, a coarsely threaded mixing section, a blank section, a mediumly threaded controlling section with medium pitches;
• said large central screw rod and said small side screw rods terminating at a pointed head housed in a plasticizing sleeve disposed at a second end of said delivery tube, through which melted plastic material is injected whereby raw plastic powder or grains can be delivered, crushed, and mixed evenly and effectively delivered along the delivery tube from said first end thereof to said second end.