Quick-release device for screwdriver bits

A quick-release device for screwdriver bits, comprising:

• a shank having a first end and a second end, the shank having a polygonal hole longitudinally defined in the first end thereof and adapted for partially receiving a bit, wherein the bit has a groove annularly defined therein, at least one slot longitudinally defined in the first end of the shank, an annular groove defined in an inner periphery of polygonal hole and communicating with the at least one slot;
• a tapered section annularly formed on an inner periphery of the annular groove toward the first end of the shank, and a divide line formed between the annular groove and the tapered section;
• an expandable locking member received in the annular groove, wherein the locking member has an outer diameter slightly smaller than a diameter of the annular groove and the locking member is adapted to be selectively engaged into indentations peripherally defined in the bit;
• a sleeve movably sleeved on the first end of the shank, the sleeve having at least one protrusion inwardly extending therefrom, wherein the at least one protrusion is engaged into the at least one slot to prevent the sleeve from being rotated relative to the hollow stub, the at least one protrusion selectively abutting against the locking member when removing the bit form the polygonal hole, wherein the sleeve has two positions, including a locking position and a releasing position, relative to the bit, the sleeve situated in the locking position relative to the bit when the protrusion is separated from the annular groove and the bit is positioned, the sleeve situated in the releasing position relative to the bit and the bit being free detached from the polygonal hole when the bottom of the protrusion moved over the divided line and into the annular groove to abut the locking member;
• and
• a stopper secured on one end of the shank for preventing the sleeve from removing from the shank.