Patent ID: 9278414
Filing Date: 2016-03-08
CPC Classification: B23P,H05B

Claim Text:
1. An induction coil unit for heating a sleeve section of a tool holder including a free end and a receiver opening for a shaft of a rotating tool, wherein said tool holder holds the shaft of the rotating tool that is coaxially disposed with respect to a rotational axis of the induction coil unit, resting in the receiver opening, in a press fit and releases the shaft of the rotating tool, when heated, the induction coil unit comprising: a coil assembly inducing Eddy currents on and enclosing the sleeve section during a heating operation, the coil assembly further including a first coaxial coil unit and a second coaxial coil unit surrounding the sleeve section which are disposed at an operatively changeable axial distance from each other, the first coaxial coil unit adjacent to the free end of the sleeve section; a first magnetic flux concentrator assembly connected to the first coaxial coil unit in an axially fixated manner, the first magnetic flux concentrator assembly made from magnetically soft material, which is electrically substantially non-conductive, the first concentrator assembly being disposed axially and radially outside of the first coaxial coil unit adjacent to the free end of the sleeve section, which can be disposed at least close to the free end of the sleeve section of the tool holder; a second magnetic flux concentrator assembly connected to the second coaxial coil unit in an axially fixated manner, the second magnetic flux concentrator assembly made from magnetically soft electrically substantially non-conductive material being provided axially and radially outside of the second coaxial coil unit remote from the free end of the sleeve section, wherein at least one of the first magnetic flux concentrator assembly and the second magnetic flux concentrator assembly comprises a portion protruding axially relative to the other one of the first and second magnetic flux concentrator assemblies, so that the first and second magnetic flux concentrator assemblies shield a magnetic field of the coil assembly to the outside extensively; and an adjustment assembly positioned radially outside of the first and second magnetic flux concentrator assemblies and including at least one helix-shaped control surface and at least one cam protrusion for adjustment of the axial distance of the first and second coaxial coil units relative to each other and the axial distance of the first and second magnetic flux concentrator assemblies relative to each other.