Chuck element for machine tools with rotating jaw chuck

A chuck system for machine tools, comprising:

• a rotating jaw chuck, clamping jaws of the jaw chuck being radially adjustable relative to an axis of rotation;
• the clamping jaws being displaceably mounted in a bearer that is connected with a drive shaft;
• engagement openings arranged in a region of the bearer for introduction of an adjustment tool for positioning of the clamping jaws;
• the bearer being surrounded by a protective sheath that is displaceably guided in a direction of the axis of rotation;
• the protective sheath comprising through openings which in a handling position of the protective sheath are arranged congruent to the engagement openings and in an operating position of the protective sheath are arranged so as to be offset to the engagement opening;
• the protective sheath at least partially radially surrounding the clamping jaws;
• two pairs of through openings are respectively arranged along a circumference of the protective sheath so as to be offset by 120.degree.;
• and
• in each pair of through openings, one of the through openings corresponds respectively with an engagement opening for radial positioning of the clamping jaws, and an additional through opening corresponds with an engagement opening for rotationally symmetrical arrangement of the jaw chuck relative to the axis of rotation.

A chuck system for an engraving cylinder in an electronic engraver, comprising:

• an electronic engraver having an engraving cylinder;
• a rotating jaw chuck for engagement with said engraving cylinder, clamping jaws of the jaw chuck being radially adjustable relative to an axis of rotation;
• the clamping jaws being displaceably mounted in a bearer;
• at least one engagement opening arranged in a region of the bearer for introduction of an adjustment tool for positioning of the clamping jaws;
• the bearer being surrounded by a protective sheath that is displaceably guided in a direction of the axis of rotation;
• the protective sheath comprising at least one through opening which in a handling position of the protective sheath is arranged congruent to the engagement opening with the sheath withdrawn from a region of a leading end of the clamping jaws, and in an operating position of the protective sheath is arranged so as to be offset to the engagement opening with the sheath radially surrounding a region of a leading end of the clamping jaws;
• and
• the protective sheath activating a cut-off switch in said handling position which prevents operating rotation of the jaw chuck.