| 摘要 |
A chuck has a chuck body defining a chuck axis and carrying three angularly equispaced and radially displaceable jaws. A tightening sleeve is rotatable on this chuck body about the axis thereof and is connected via formations to the jaw and chuck body so that when it is rotated in one rotational sense it displaces the jaws radially inwardly and when rotated in the opposite rotational sense it allows outward displacement of these jaws. An axially centered array of ratchet teeth is formed on the sleeve and a ratchet is pivoted on the chuck body and has an end engageable with the ratchet teeth so that when engaged the sleeve can only rotate in the one rotational sense for tightening of the jaws relative to the chuck body. A radially outwardly displaceable counterweight is carried on this ratchet to urge it into engagement with the teeth when the chuck is rotated, but the ratchet can be manually moved out of engagement with the teeth to allow manual loosening of the chuck. |
