High-frequency spindle

1. A high-frequency spindle comprising:

a tube shaft extending along and rotatable about an axis and having a front end;

a chuck carried on the front end of the shaft and adapted to fit with a tool or tool holder;

a ball cage in the shaft and having a radially open window;

a biaser housing holding the ball cage in the shaft and in which the ball cage can move axially;

a locking ball radially displaceable in the window between a holding position engaging in a seat of the tool or tool holder and a freeing position clear of the seat;

an angled surface engageable radially with the ball;

an actuating rod axially shiftable and coupled to the cage or to the angled surface;

actuating means for axially shifting the rod and thereby relatively axially displacing the ball and the angled surface and calming the ball with the angled surface into the holding position;

a primary spring biasing the rod and urging the ball with the angled surface into the holding position; and

a secondary spring braced directly between the biaser housing and the ball cage and urging the ball cage axially oppositely to a direction in which the primary spring biases the rod.

2. The high-frequency spindle defined in claim 1 , there are at least two such locking balls.

3. The high-frequency spindle defined in claim 1 , wherein an outside diameter of the high-frequency spindle is smaller than 15 mm.

4. The high-frequency spindle defined in claim 3 wherein the outside diameter is smaller or equal to 10 mm.

5. The high-frequency spindle defined in claim 4 , wherein the tool and the tube shaft are formed centered on the axis with interfitting collars and one of the collars is formed with a radially open groove forming the seat.

6. The high-frequency spindle defined in claim 5 , wherein the collars fit complementarily together and have complementary radially interengaging surfaces.

7. The high-frequency spindle defined in claim 1 , further comprising:

structure limiting axial travel of the ball cage in the biaser housing.

8. The high-frequency spindle defined in claim 1 , wherein the angled surface is formed on the rod.

9. The high-frequency spindle defined in claim 1 , wherein the actuating means has a cylinder and plurality of axially spaced cylinders therein coupled axially together and forming a plurality of axially spaced pressurizable compartments.

10. The high-frequency spindle defined in claim 9 , wherein the actuating means further has respective axially fixed cylinder cups each forming with a respective one of the cylinders the respective compartment.

11. The high-frequency spindle defined in claim 10 , wherein each cylinder cup forms with the tube shaft a gap through which the respective chamber can be vented.

12. The high-frequency spindle defined in claim 1 , wherein the actuating means includes a double-acting cylinder having a piston formed with the angled surface.

13. The high-frequency spindle defined in claim 12 , wherein the rod has an angled face adjacent the angled surface and axial displacement of the face and surface relative to each other cams the rod axially forward.

14. The high-frequency spindle defined in claim 13 , wherein the surface and face are angled for force multiplication in that a movement of the piston through a predetermined stroke creates a movement of the rod through a stroke larger than the predetermined stroke.

15. The high-frequency spindle defined in claim 1 , wherein the tool has a shank with a standard dimension and is formed with a radially open groove forming the seat.

16. The high-frequency spindle defined in claim 15 wherein the tool has a diameter smaller than or equal to 3 mm.