| 摘要 |
A body 52 of a chuck 30 has an axial opening 34 and is formed with three spaced radial slots 58 which receive three respective locking fingers 68 extending radially inward from a circular band 66. The band 66 is located outside of, and rotatable relative to, the body 52. The band 66 and the locking fingers 68 form a latching unit 64 which is confined to a transaxial plane 61. A spring 70 is attached the latching unit 64 and to the body 52 and normally urges each of the locking fingers 68 against one end of the respective slots 58. A plurality of spaced ribs 54 extend radially inward from an inner wall of the opening 34. A bit 36 is formed with a shank 38 having a plurality of axial grooves 42 which extend through a free end of the shank. A wall of each groove 42 is formed with a transaxial groove 50 at a prescribed distance from the free end of the shank 38. Slanted surfaces 44 on the free end of the shank 38, being inserted into the opening 34, engage and cam the respective locking fingers 68 into alignment with the axial grooves 42, which allows the shank to inserted further. The locking fingers 68 are prevented from returning to their original position until the fingers are aligned with, and biased into, the transaxial grooves 50 to lock the shank with the chuck 30. |
