Screw centering device for use in screw machine, has external ring coaxially arranged with screwing casing and comprising inlet, where internal surface of inlet is in concave conical form and used as guide track of screw

摘要

The device has an external ring (20) coaxially arranged with a screwing casing (10) and sliding on the screwing casing against action of elastic recall force between an advanced position and a retracted position with respect to an entrance of the screwing casing. The external ring comprises an inlet (21), where an internal surface (22) of the inlet is in a concave conical form and used as a guide track of a screw. The external ring is attached with the screwing casing by a pin (35) that is mounted in a radial opening of the external ring.