| 摘要 |
<p>A core lifter assembly (12) comprises a combination of a core lifter ring (10) and a core lifter case (14). The ring (10) has an ax!a!!y extending portion (16) of an outer generally frusto-conical configuration having an included taper angle ß. The included taper angle ß is also the taper angle of the outer circumferential surface (18) of the ring (10). The included taper angle ß may in alternate embodiments be = 6°; > T°; = 8°; or = 10°. In one embodiment an upper limit of the included taper angle ß may be about 30°. Thus in one embodiment the included taper angle ß may be expressed by the relationship: 30° = p = 6°. Further, the angle ß may comprise any sub range within the aforementioned range of 6 - 30°. However in other embodiments the taper angle may exceed 30°.</p> |
