BOORVOERING.

摘要

A drill chuck normally has a chuck body rotatable about a chuck axis and provided at its front side with a plurality of axially forwardly projecting and radially displaceable jaws. A tightening ring rotatable on the body about the axis thereof is connected via appropriate screwthread formations to the jaws so that when this ring is rotated on the chuck body about the axis in a tightening direction the jaws are displaced radially toward each other and when rotated in an opposite loosening direction the jaws are displaced apart. In addition the chuck body is formed with a radially outwardly open groove having a rear surface and with a radially outwardly open recess spaced axially forwardly of the groove and having an inner surface extending generally perpendicularly of the chuck axis and having a front portion spaced axially from and confronting the rear surface. This groove receives a tightening ring which has rear and front edge surfaces respectively riding on the front and rear surfaces of the groove, so that the front edge surface is spaced axially from and confronts the portion of the inner surface. A locking element is rotatable in this recess about a locking axis transverse to the chuck axis between a locking position wedged tightly between the front edge surface and the portion and an angularly offset unlocked position out of engagement with the front edge surface. Thus the locking element can be rotated into the locking position to block rotation of the tightening ring on the chuck body.