Drill chuck

A chuck comprising:

• a chuck body defining a chuck axis and formed with an annular body surface centered on said axis, lying in a plane substantially perpendicular to said axis, and facing in one axial direction;
• a plurality of generally angularly equispaced and radially displaceable jaws on said body;
• a tightening sleeve rotatable on said body about said axis;
• means including formations on said jaws, on said body, and on said sleeve for displacing said jaws radially inwardly on rotation of said sleeve on said body in one rotational sense and for permitting radial outward displacement of said jaws on rotation in the opposite sense;
• an array of radially extending sleeve teeth on said sleeve angularly spaced about said axis and defining intertooth gaps, each sleeve tooth having a sleeve-tooth surface generally parallel to, axially confronting, and axially spaced from said annular body surface;
• a bearing ring centered on said axis and received between said sleeve teeth and said annular body surface, said ring being at least limitedly rotatable about said axis relative to said sleeve and having a ring surface axially confronting and spaced from said annular body surface;
• an array of radially extending ring teeth on said ring and similar to said array of sleeve teeth, each ring tooth having one axially directed face engageable with said sleeve-tooth surfaces and another oppositely axially directed face confronting and axially spaced from said annular body surface;
• a plurality of roller elements between and riding on said body and ring surfaces;
• and
• a locking element engaging through at least one of said intertooth gaps and holding said ring teeth in axial alignment with said sleeve teeth with said one faces of said ring teeth bearing flatly on said sleeve-tooth surfaces, whereby said locking element prevents rotation of said ring relative to said sleeve.