Machine tool

1 . A machine tool for the machining of elongate workpieces, the machine tool comprising:

a workpiece support column having a first workpiece support side, wherein the first workpiece support side comprises first workpiece support means for supporting a first workpiece and comprises second workpiece support means for supporting a second workpiece, the first workpiece support means and the second workpiece support means being arranged for supporting the first workpiece vertically above the second workpiece; and

a machining station comprising at least a first tool spindle for machining the first workpiece, and a second tool spindle for machining the second workpiece;

wherein the workpiece support column is rotatable around a vertical axis so as to shift the workpieces between the machining station and a station for loading and unloading of workpieces;

wherein

the first workpiece support means comprise at least a first chuck for clamping a first end of the first workpiece, and a first additional support element for supporting a second end of the first workpiece, the first chuck and the first additional support element facing each other along a first horizontal axis so as to allow for rotation of the first workpiece around the first horizontal axis,

wherein

the second workpiece support means comprise at least a second chuck for clamping a first end of the second workpiece and a second additional support element for supporting a second end of the second workpiece, the second chuck and the second additional support element facing each other along a second horizontal axis so as to allow for rotation of the second workpiece around the second horizontal axis,

wherein

the first workpiece support means comprise drive means for applying torque to the first workpiece via the first chuck to rotate the first workpiece around the first horizontal axis for machining of the first workpiece by turning,

and wherein

the second workpiece support means comprise drive means for applying torque to the second workpiece via the second chuck to rotate the second workpiece around the second horizontal axis for machining of the second workpiece by turning.

2 . The machine tool according to claim 1 , wherein the first additional support element is a third chuck for clamping the second end of the first workpiece, wherein the second additional support element is a fourth chuck for clamping the second end of the second workpiece, wherein the first workpiece support means comprise drive means for applying torque to the first workpiece via the third chuck to rotate the first workpiece around the first horizontal axis for machining of the first workpiece by turning, and wherein the second workpiece support means comprise drive means for applying torque to the second workpiece via the fourth chuck to rotate the second workpiece around the second horizontal axis for machining of the second workpiece by turning.

3 . The machine tool according to claim 2 , wherein the machine tool is arranged for selectively retracting workpiece clamping jaws of one of the first chuck and the third chuck, and of one of the second chuck and the fourth chuck, while applying torque to the respective workpiece via the other one of the first chuck and the third chuck, and via the other one of the second chuck and the fourth chuck, so as to allow for machining of the workpieces along their entire lengths, while the workpieces remain axially and radially fixed by the first and second workpiece support means.

4 . The machine tool according to claim 2 , wherein each of the first and third chucks comprises jaws arranged to apply pressure onto a surface of the first workpiece in a radial direction to allow torque to be applied to the first workpiece via the respective chuck, and whereas the machine tool is arranged to selectively

withdraw the jaws of the first chuck from the first workpiece to allow for machining of part of the first workpiece while rotating the first workpiece by applying torque to the first workpiece via the third chuck, and

withdraw the jaws of the third chuck from the first workpiece to allow for machining of part of the first workpiece while rotating the first workpiece by applying torque to the first workpiece via the first chuck.

5 . The machine tool according to claim 1 , wherein the workpiece support column has a second workpiece support side angularly spaced from the first workpiece support side, the second workpiece support side comprising third workpiece support means for supporting a third workpiece and fourth workpiece support means for supporting a fourth workpiece, the third workpiece support means and the fourth workpiece support means being arranged for supporting the third workpiece vertically above the fourth workpiece.

6 . The machine tool according to claim 5 , wherein the third workpiece support means and the fourth workpiece support means are different from the first workpiece support means and the second workpiece support means, in order to allow machining operations to be carried out on respective workpieces supported on the second workpiece support side that cannot be carried out on respective workpieces supported on the first workpiece support side, due to the manner in which the respective workpieces are supported on the first workpiece support side.

7 . The machine tool according to claim 1 , wherein the workpiece support column, including the first workpiece support means and the second workpiece support means, is dimensioned to fit into a cylinder that is co-axial with the vertical axis and that has a diameter of less than 2.5 m, while allowing for machining workpieces having a length of 0.75 m by turning said workpieces.

8 . The machine tool according to claim 1 , wherein the drive means are configured for rotation of the respective workpiece by more than 100 rpm.

9 . The machine tool according to claim 8 , wherein the drive means are configured for rotation of the respective workpiece by more than 200 rpm.

10 . The machine tool according to claim 1 , wherein at least one of the workpiece support means comprises an electric motor comprising a stator and a rotor placed radially inside the stator, a hollow workpiece-spindle extending through the rotor, the workpiece-spindle having a first end and a second end, a retractable jaw chuck being the first chuck or the second chuck, the retractable jaw chuck being at least partly arranged within the workpiece-spindle at the second end of the workpiece spindle, the retractable jaw chuck comprising jaws for clamping the respective workpiece, wherein the workpiece-spindle is surrounded by the rotor at a position between the first end of the workpiece spindle and the second end of the workpiece spindle, wherein the workpiece-spindle is rotationally fixed to the rotor so that it rotates with the rotor, wherein the workpiece-spindle has a first inner diameter at the first end of the workpiece spindle and a second inner diameter at the second end of the workpiece spindle, wherein the rotor has a third inner diameter, wherein the second inner diameter is substantially larger than the first inner diameter and/or than the third inner diameter.

11 . The machine tool according to claim 1 , wherein at least one of the workpiece support means comprises an electric motor comprising a stator and a rotor placed radially inside the stator, a hollow workpiece-spindle extending through the rotor, the workpiece-spindle having a first end and a second end, a retractable jaw chuck being the first chuck or the second chuck, the retractable jaw chuck being at least partly arranged within the workpiece-spindle at the second end of the workpiece spindle, the retractable jaw chuck comprising jaws for clamping the respective workpiece, wherein the workpiece-spindle is surrounded by the rotor at a position between the first end of the workpiece spindle and the second end of the workpiece spindle, wherein the workpiece-spindle is rotationally fixed to the rotor so that it rotates with the rotor, wherein the workpiece-spindle has a first inner diameter at the first end of the workpiece spindle and a second inner diameter at the second end of the workpiece spindle, wherein the rotor has a third inner diameter, wherein the second inner diameter is substantially larger than the first inner diameter and/or than the third inner diameter, wherein the workpiece-spindle is rotationally supported by a first bearing placed at the first end of the workpiece-spindle or between the rotor and the first end of the workpiece spindle, and a second bearing placed at the second end of the workpiece-spindle or between the rotor and the second end of the workpiece spindle, the first bearing having a fourth inner diameter and the second bearing having a fifth inner diameter, wherein the workpiece-spindle has an axial length between the first end of the workpiece spindle and the second end of the workpiece spindle, wherein the axial length is less than three times the fifth inner diameter, the machine tool being arranged for turning of workpieces having a maximum diameter S, wherein the fifth inner diameter is larger than 0.5 S.