| 摘要 |
PURPOSE:To prevent a screw shaft from escaping outside and being brought into contact with a shaft cover and to prevent a product of inferior quality from occurrence caused by partial shortage of a material by providing two screw shafts, a long one and a short one, projecting in parallel the apex of the longer screw shaft more than the apex of the shorter one and making the diameter of the longer one larger than that of the shorter one. CONSTITUTION:Fins 1a and 2a are spirally formed on the whole length of a longer screw shaft 1 and a shorter screw shaft 2 and the screw shaft 2 has a smaller diameter than that of the screw shaft 1 and the rotation of both shafts are in the reverse directions each other. A hopper 14 for material feeding is provided above intermediate parts 1c and 2c of the screw shafts 1 and 2 arranged in parallel and when a prekneaded material is put in the hopper 14, it is bited between the intermediate parts 1c and 2c and is fed into the apex side. In this instance, even if a force pushing each screw shaft 1 or 2 outside acts, as the longer screw shaft 1 is thicker, the screw shaft 1 is hardly bent. In addition, the side of a shaft cover 18 part wherein the crew shaft 2 exists is separated in such a way that it is not brought into contact with the screw shaft 2 even if the screw shaft 2 is bent. |
