Tool revolver unit for a machine tool

A tool revolver unit for a machine tool for machining workpieces, comprising:

• a housing having an axis;
• a tool disk coupled to said housing to rotate about said axis relative to said housing;
• a locking device in said housing movable between locking and unlocking positions locking and unlocking said tool disk to prevent and allow rotation of said tool disk relative to said housing, respectively;
• first and second rotary drives mounted in said housing, said first rotary drive coupled to said tool disk for rotation of said tool disk, said second rotary drive including a servomotor moving said locking device between the locking and unlocking positions;
• said locking device including toothed elements with Hirth couplings, said toothed elements being relatively movable along said axis into and out of engagement with one another;
• said second rotary device being connected to a control gear transforming rotation produced by said servomotor into axial displacement by an axially movable toothed element of said toothed element;
• said control gear including a cam ring with a control curve connected to said rotor of said second rotary drive and mounted rotatably movable and axially immovable in said housing, said movable toothed element being guided on said control curve during rotation of said cam ring to move along an axial stroke;
• said control curve including a track concentric to said axis, guide rollers on said axially movable toothed element being on said track and forming a locking ring, said rollers forming cam sensing devices;
• a prestressing device on said locking ring holding said rollers by friction in contact with said control curve;
• and
• said prestressing device biasing said locking ring for axial movement away from the locking position and toward the unlocking position.