Tool unit and switchable tool system for a tool unit

A tool unit for machining edges of a workpiece, wherein the tool unit extends along a rotational axis, the tool unit comprising:

• a tool head extending along the rotational axis and defining a circumference;
• a drive motor configured to rotationally drive said tool head about the rotational axis and having a housing part;
• a switching drive for said tool head;
• said tool head including a first tool section having a set of first blades distributed over the circumference;
• said tool head including a second tool section having a set of second blades distributed over the circumference;
• each of said second blades being positioned between two of said first blades as viewed in a circumferential direction;
• said second tool section being configured to be movable to and fro between a passive position and an active position relative to said first tool section in a direction of the rotational axis via said switching drive;
• said second blades being axially retracted with respect to said first blades when said second tool section is in said passive position;
• said second blades being axially projected with respect to said first blades when said second tool section is in said active position;
• said switching drive including:
• (i) at least one electromagnet, and (ii) an actuating armature which is made from a magnetically attractable material and is arranged in a region of action of said at least one electromagnet;
• said at least one electromagnet being positioned in an axial direction between said tool head and said drive motor;
• said at least one electromagnet being fastened to said housing part of said drive motor such that said at least one electromagnet cannot be rotated;
• said actuating armature being fixedly connected to said second tool section;
• and,
• said at least one electromagnet and said actuating armature defining a gap both when said second tool section is in said passive position and when said second tool section is in said active position.