Spannbacken.

摘要

The profiles of the threads on the jaws (30) of a chuck, such as a three-jawed chuck, are modified so that at least one end (38a, 38b) of the jaw thread segments (34) curve in away from the threads on the nut which operate the jaws. This prevents the end edges of the jaw thread segments from digging into the nut threads when the nut is rotated to operate the jaws.