| 摘要 |
PROBLEM TO BE SOLVED: To provide an improved chuck. SOLUTION: This chuck includes a generally columnar main body, and a plurality of jaws communicating with a shaft hole of the main body and disposed movably to the main body. A generally columnar sleeve is effectively coupled with the jaw and rotatably installed to the main body. Rotations in a direction closing the sleeve make the jaw move close to the axis of the shaft hole, and rotations in a direction opening the sleeve make the jaw move apart from the shaft hole. A bearing has a first lace adjacent to the main body, a second lace adjacent to the sleeve, and at least one bearing element disposed between the first and second laces. The first and second laces form a ratchet and a claw biased to the ratchet. The ratchet and the claw are structured to prevent the rotations in the opening direction, when the claw is engaged with the ratchet. |
