Abstract: A spindle head for a tool turret has a housing in which a spindle is mounted rotatably. A rotation lock for the spindle includes a bushing arranged to be longitudinally slidable but nonrotatable on the spindle. A securing element is provided on the bushing. The bushing securing element, in its work setting, engages a securing element on the housing, limiting the axial movement of the bushing relative to the housing in the direction of the form-locking engagement of the two securing elements, and can be disengaged by an axial movement of the bushing counter to the force of a prebiased spring in a direction away from the housing securing element. At least some of the cooperating surfaces of the securing elements in the work setting are inclined with respect to the axial direction to a degree that excludes self-locking.

Abstract: A tool turret includes two toothed rims concentric to the rotary axis of its turret head and arranged radially adjacent to one another. One rim is immovable relative to the turret head. The other rim is immovable relative to the turret housing. The teeth of the toothed rims point toward a position-locking member arranged in an axial direction adjacent and coaxial to both of the toothed rims. The toothed rims can be held by a piston which is axially slidable to a position-locking setting, in which its teeth engage the teeth of the two toothed rims without any play. The piston is part of a pneumatic assembly. The angle formed by the sides of each tooth of the toothed rims and the position-locking member is reduced from the conventional value of 60.degree.