| 摘要 |
A conical member (12) comprises a base (14), an outer mantle surface (13) with a predetermined slope, and a holder for connection rods. The holders are in or on a ring shaped member whose inner dia. is less than or equal to the outer dia. of the base, and greater than or equal to the outer dia. of the conical member at its tip. The ring shaped member (1) inner wall has the same slope as the outer mantle surface. An Independent claim is included for the ring shaped member(1). |
