received by the International Bureau on 18 June 2018 (18.06.2018)

1. Structural suspension of radial turret bearing wheels (16) in a turret bearing (6), comprising: a rail support structure (13) mounted on a turret bearing support structure (7), a circular rail (14) mounted to the rail support structure,

a plurality of radial wheels (16) running on the mainly vertical inner side of the rail (14),

a mainly vertical flexible shaft (18), for each radial wheel (16) being supported by an upper and lower support (45, 33) with a part of the shaft protruding like a cantilever with the radial wheel mounted close to the outer end, wherein the inner side (49) of the rail (14) is a frustum with the shortest radius at the top,

wherein the outer mainly planar contacting surface of the wheel (50) has an angle Θ relative to the rotational axis of the wheel, and is overlaid with a convex curvature across the contacting surface (50),

characterized in that a distance between a radial wheel and the inner side of the rail is adjusted by: the shaft comprising at least two lockable rotational positions,

an upper shaft portion (38) of the shaft having a centerline offset relative to the rotational axis of the shaft (18),

2. Suspension according to claim 1 wherein the at least two lockable positions are provided by the lower shaft support comprising a shape that mates with a similar shape on the lower end of the shaft in at least two angular positions.

3. Suspension according to claim 2 wherein the shape on the lower shaft support is a hexagon or octagon.

4. Suspension according to claim 2 wherein the shape on the lower shaft support is a cogwheel with at least two teeth.

5. Suspension according to claim 1, wherein the axis of the wheel is tilting an angle A relative to the unloaded condition of the axis, when the shaft is under maximum load, and wherein an angle E between the inner side (49) of the rail and the tangent of the curvature across the contacting surface (50) is less than zero at the top for conditions without load and larger than A at the bottom for conditions with maximum load.

6. Suspension according to claim 1 wherein a pipe (25) is mounted between the lower shaft support (33) and the upper shaft support (45) to cover the shaft.

7. Suspension according to claim 1 wherein the radial wheel is supported by a bushing (30, 30'), which is able to slide on the shaft the same distance as the maximum vertical movement of the turret relative to the rail under maximum load and the vertical movement imposed by the angular deflection A of the wheel.

8. Suspension according to claim 1 wherein a flange (29) is mounted on the upper rim of the radial wheel (16).

9. Suspension according to claim lwherein the radial wheel (16) is vertically locked to the rail (14) by having a lower flange (57) mounted on the top rim of the wheel.

10. Suspension according to claim 1 wherein the outer mainly planar surface of the wheel (50) with an angle Θ relative to the rotational axis of the wheel is overlaid with a convex curvature having a shorter radius at the top and a longer radius at the bottom.

11. Suspension according to claim 1 wherein the upper shaft support (45) comprises a spherical bearing assembly (21) comprising a spherical ring (23) with a sliding surface and a spherical ball (22) inside the ring with a material matching the sliding surface of the ring (23), and a housing (24) comprising a top lid (27) fastened to the housing by bolts (26).

12. Suspension according to claim 1 wherein a cantilevered length, HI, between the upper shaft support (45) and the center of the radial wheel (16) is about three times the length, H2, between the lower and upper shaft support (33, 45).

13. Suspension according to claim 1 wherein the cross section of the shaft 18 is tapered downward and upward from the largest diameter dl at the upper horizontal shaft support (45), downward to a diameter d3 at the lower shaft support 33 and upward to a diameter d2 at the lower side of the radial wheel (16), wherein d2 is in the range of 50 to 80 % of dl and d3 is in the range of 40 to 60 % of dl.

14. Suspension according to claim 1 wherein the material of the shaft is a steel alloy comprising Molybdenum and Chrome.