Patent ID: 6900418

Claim:
Arrangement for inductively heating a sleeve section ( 5 ) which contains a central accommodating opening ( 9 ) for a shank ( 11 ) of a rotary tool and belongs to a tool-holder ( 1 ), which retains the tool shank ( 11 ), seated in the accommodating opening ( 9 ), with a press-fit and releases it when heated, comprising: an induction coil ( 13 ), which encloses the sleeve section ( 5 ) of the tool-holder ( 1 ), the coil having a central longitudinal axis, and a generator ( 17 ), which supplies the induction coil ( 13 ) with electric current of periodically changing amplitude, characterized in that—as seen in an axial-longitudinal-section plane of the induction coil ( 13 )—the number of coil turns of the winding ( 19 ) of said induction coil per unit of length in the direction of the coil axis ( 7 ) and/or the number of coil turns per unit of surface area of the axial-longitudinal-section plane is smaller in an intermediate region located, in the direction of the coil axis ( 7 ), between two main winding regions ( 21 , 23 ; 61 - 69 ) than in the two main winding regions ( 21 , 23 ; 61 - 69 ) and/or the internal winding diameter is smaller in the two main winding regions ( 21 , 23 ; 61 - 69 ) than in the intermediate regions and/or the internal winding diameter, at least in an axial sub-region of the induction coil ( 13 ), increases from the two main winding regions ( 21 , 23 ; 61 - 69 ) in the direction of the intermediate region.