| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a screw injection device that can be implemented at a low cost and in which galling and seizure are hardly caused on the outer surface of a check ring and the inner surface of a heating cylinder. <P>SOLUTION: A screw 8 is constituted of a screw body 31 on which a helical groove 8a is formed, and a screw head 33 that is fixed on the tip thereof via a small-diameter neck 32. A backflow-preventing device 40 is constituted of a check seat 41 that is fixed on the end of the screw body 31 on the screw head attachment side, and a check ring 42 that is mounted on the neck 32 so as to be capable of rotating and moving forward and backward. On the end face of the screw head 33 on the check ring 42 side, a plurality of loose ball-fitting grooves 44 that have a deep groove section 44a and a shallow groove section 44b are formed. Balls 43 which are accommodated in the respective loose ball-fitting grooves 44 so as to be capable of rolling, are disposed between the screw head 33 and the check ring 42. <P>COPYRIGHT: (C)2013,JPO&INPIT |
