Power drill with compact chuck assembly

Abstract

A drill has a drill housing and a drive spindle centered on and rotatable about an axis, projecting axially outward from the housing, and having an outer end. A chuck element is fixed on the spindle outer end and an annular formation is axially fixed on the housing, centered on the axis, and extends axially to the chuck element. The formation defines with the chuck element an annular chamber. An adjustment ring element is axially fixed but rotatable about the axis on the chuck element. One of the elements is formed with a plurality of axially forwardly open guide passages open axially rearward into the chamber and the other of the elements is formed with a screwthread centered on the axis. The elements both are rotatable about the axis relative to the formation. Respective jaws can move in the passages between axially front and radially closely spaced positions and axially back and radially widely spaced positions and have teeth meshing with the screwthread so that rotation of the ring element in a forward direction on the chuck element displaces the jaws axially forward and radially inward and opposite rotation of the ring element in a reverse direction on the chuck element displaces the jaws axially backward and radially apart. The jaws project rearward from the one element into the chamber in the back positions.