| 摘要 |
<p>A method for effecting the injection operation in injection moulding and blowing machines, with a revolving and axially removable screw, and using a non-return device formed by a damming ring, has this damming ring so constructed that it is compelled to rotate at the same speed as the screw. In the prefd. appts., the dam ring is axially slidable upon a portion of the screw shaft between the conical head and the front end of the bladed portion of the screw. The inside aperture of the ring has shoulders which bear against corresponding shoulders on the shaft of the screw, thus causing the ring to rotate with the screw. The rotation avoids friction between ring and screw thus considerably reducing wear.</p> |
