Keyless drill chuck

A keyless chuck apparatus for holding cylindrically shaped tool bits of different diameters, comprising:

• a) a tool body that has proximal and distal end portions;
• b) the tool body having a tool body wall with an outer wall surface, and an inner wall surface that defines a central longitudinal bore that extends from a position adjacent the proximal end of the tool body toward the distal end thereof, the bore having a central longitudinal axis;
• c) at least one bearing holder that registers in the bore, said holder comprising an annular member with a central opening that coincides with the central longitudinal axis of the tool body bore during use;
• d) at least one bearing carried in the bearing holder;
• e) cam surface means carried by the tool body wall at the inner wall surface for moving the bearing to grip the tool bit when the tool body is moved relative to the tool bit, said cam surface means including a recess portion that includes an arcuate recess wall extending from the tool body wall inner surface toward the outer wall surface, the recess wall being sized and shaped to vary the recess thickness along a radial line;
• f) means for pre-loading the interface between the bearing and the tool bit, so that the bearing is biased to bear against the tool bit and the inner wall of the tool body at the cam surface means;
• and
• g) release means for disengaging the spring means so that a drill bit can be inserted into the tool body bore or removed therefrom.

A keyless chuck apparatus for holding cylindrically shaped tool bits of different diameters, comprising:

• a) a tool body that has proximal and distal end portions;
• b) the tool body having a tool body wall with an inner surface that defines a central longitudinal bore that extends from a position adjacent the proximal end of the tool body toward the distal end thereof, the bore having a central longitudinal axis;
• c) at least one bearing holder that registers in the bore, said holder comprising an annular member with a central opening that coincides with the central longitudinal axis of the tool body bore during use;
• d) at least one bearing carried in the bearing holder;
• e) cam surface means carried by the tool body wall at the inner surface for moving the bearing to grip the tool bit when the tool body is moved relative to the tool bit;
• f) means for pre-loading the interface between the bearing and the tool bit, so that the bearing is biased to bear against the tool bit and the inner wall of the tool body at the cam surface means;
• g) release means for disengaging the spring means so that a drill bit can be inserted into the tool body bore or removed therefrom;
• and
• h) one of the bearing holders and the tool body each have a transverse slot therethrough, and further comprising a transverse peg member for insertion through the slots to hold the bearing member in a fixed position relative to the tool body end portions.