Chuck with jaws having curved engagement surfaces

Abstract

A chuck for holding a workpiece in a machine such as a lathe including a jaw holder having a front side facing in the direction of the workpiece and radially extending slots in this front side. There is a mechanism for attaching the holder to the machine for turning about a central axis. Several jaw devices are detachably mounted in these slots and are radially movable therein. Each jaw device has an inner workpiece engaging surface that forms a profile when it is viewed from the front of the jaw device in the direction of the central axis. This profile comprises a central concave arc and two similar convex curves located at opposite ends of the concave arc. In a preferred version, the chuck is a scroll chuck having a scroll member rotatably mounted in the holder. The workpiece engaging surfaces can be serrated to increase gripping ability.

Dependencies are inferred from the claim text.