| 摘要 |
PURPOSE:To secure such chucking force as being powerful and eliminating any shaky motion, by increasing a nipping engagement area of a jaw, while making powerful driving force act on a work. CONSTITUTION:A center hole being made up in one-side end face of a work member is adjusted to fit a tip end of a center piece 8, while the work member is set thereto as thrusting a center of a tailstock into a center hole made up in an end face of the rest other side. At this time, simultaneously with the center piece 8 thrust in, a jaw 11 of each driving plate 10 is nipped in the end face of the work member. Each plate 10 is pushed back by the end face of the work member, and it contacts a taper surface part 13 of a ring 12 whereby the plate 10 is forcibly pressed to the bottom of a groove 9, thus lost motion is prevented from occurring. |
