Abstract: The present invention relates to a device for tensioning or de-tensioning tools, having a tool shaft in a tool chuck which has a sheath section open on the free end thereof and which is made of electrically conductive material, for receiving the tool shaft in a friction connection, having an induction coil which surrounds the sheath section of the tool chuck, to which preferably high-frequency alternating current can be applied, and which is designed as a ring or cylinder coil, wherein the device has at least one channel running between the inner peripheral surface of the induction coil and the sheath section of the tool chuck, through which flows a cooling agent which cools the sheath section of the tool chuck.

Abstract: A balance ring for a component (1) rotating about a rotation axis (3), for example a tool holder for a rotating tool or else a machine spindle or the like, is proposed. The balance ring has an annular body (11) which is rotationally symmetrical with respect to an axis of rotational symmetry, a guide arrangement (13) guiding the annular body (11) in a radially movable but axially fixed manner on the component (1) with an axis of rotational symmetry essentially parallel to the rotation axis (3) of the component (1), and a plurality of adjusting elements (21) arranged in the circumferential direction of the annular body (11), preferably at equal angular distances from one another, radially supported between the annular body (11) and the component (1) and having a variable radial supporting length. The guide arrangement may be designed as an axially extending spring link arrangement or else as spring webs extending in the circumferential direction.