1. A chuck for use with a manual or powered driver having a rotatable drive shaft, the chuck comprising:a generally cylindrical body having a nose section, a tail section and a center axis, the tail section being configured to rotate with the drive shaft and the nose section having an axial bore formed therein and a plurality of passageways formed therethrough and intersecting the axial bore;
a plurality of jaws movably disposed in the passageways;
a nut rotatably mounted about the body and in operative communication with the jaws so that rotation of the nut in a closing direction moves the jaws toward the center axis of the body and rotation of the nut in an opening direction moves the jaws away from the center axis;
a generally cylindrical sleeve rotatably mounted about the body, the sleeve including an inner surface defining a first recess, a second recess, and a drive slot, the sleeve being in operative communication with a drive dog that is slidably received in the drive slot and rotates with the nut so that the sleeve rotationally drives the nut via the drive dog but the sleeve is rotatable with respect to the nut between a first rotational position of the sleeve where the drive dog is adjacent a first side of the drive slot and a second rotational position of the sleeve where the drive dog is adjacent a second side of the drive slot;
an annular array of locking teeth non-rotatably fixed to the body; and
a locking pawl including a mounting portion and an engagement portion, the mounting portion being non-rotatably fixed to the nut in a fixed position by being mounted on the drive dog such that the locking pawl rotates with the nut, and the engagement portion having a biasing cam, and a first leg and a second leg extending radially inwardly therefrom so that the first leg and the second leg define an acute angle therebetween and the engagement portion defines a convex outer surface and a concave inner surface disposed in facing relationship with the locking teeth,
the engagement portion being radially movable with respect to the body, the engagement portion and the locking teeth being configured so that when the engagement portion engages the locking teeth, the engagement portion and the locking teeth prevent the nut from rotating in the opening direction with respect to the body,
wherein the biasing cam of the engagement portion is received in the first recess and is disengaged from the locking teeth so that the first leg and the second leg define a first acute angle value therebetween when the sleeve is in the first rotational position, and the biasing cam of the engagement portion is received in the second recess and engages the locking teeth so that the first leg and the second leg define a second acute angle value therebetween when the sleeve is in the second rotational position, the engagement portion being compressed between the locking teeth and the second recess in the second rotational position so that an amount of force is exerted on the nut in the closing direction by the engagement portion, and the second acute angle value is greater than the first acute angle value.