Draw down chuck

摘要

A drawn down chuck for gripping the inner or outer diameter of a workpiece. The chuck includes rotatable jaws disposed in a chuck body. The rotatable jaws helically and then linearly retract into the chuck body to secure workpieces having a shaft and an enlarged offset such as a hub or flange proximate to the end of the shaft. Cam assemblies interact with the jaw rods to provide the helical and linear movement. The cam assemblies include a cam groove and a cam follower, wherein the cam groove has a linear and a helical segment. The cam follower is operatively engaged on the cam groove as the jaw rod moves between the extended and retracted position so that when the jaw rod is retracted it first moves helically and then axially.