Tool turret with reduced switching times

A tool turret, comprising:

• a turret housing having an annular surface with axially extending teeth and tooth spaces, having a contact surface, and defining a rotational axis perpendicular to said annular surface and said contact surface;
• a turret head rotatably mounted in and relative to said turret housing to selectable angular positions about said rotational axis, said turret head having recesses for tools, axially extending teeth and tooth spaces, and an annular surface;
• a preliminary indexing bolt for securing said turret head in one of said angular positions following a switching operation in which said turret head moves between angular positions;
• a three-phase asynchronous motor forming a rotary drive for said turret head, said motor being pole reversible and having at least first and second sets of pole pairs, said first set providing a first indexing speed, said second set having a smaller number of pole pairs then said first set and providing a second indexing speed;
• an interlocking device for securely interlocking said turret head in any of said angular positions, said interlocking device including an interlocking member with axially extending teeth concentrically mounted about said rotational axis and a contact surface perpendicular to said rotational axis, said interlocking member being axially slidable along said rotational axis between an interlocking position, in which said interlocking member teeth simultaneously engage said teeth and tooth spaces of said turret housing and said turret head, and a contact position in which said contact surfaces of said interlocking member and said turret housing engage precluding engagement of said teeth of said interlocking member and said turret housing in any position other than said selectable angular positions of said turret head;
• a control member having a control cam rotatable relative to said interlocking member for controlling axial movement of said interlocking member, said control member being rotatably coupled to said motor;
• gear means for coupling said motor to said turret head such that said turret head reaches an indexing speed limited by characteristics of said preliminary indexing bolt;
• and
• control means for regulating operation of said preliminary indexing bolt and said motor, said control means operating the motor with said first set of pole pairs at a time to ensure deceleration of said turret head to said first indexing speed before movement of said turret head is stopped by said preliminary indexing bolt.