Method and arrangement related to a rotator

1. An arrangement related to a rotator, whereby the rotator ( 10 ) comprises a stator ( 20 ) and a rotor ( 30 ), characterized in that the arrangement comprises a fastening ring ( 50 ) for attaching a work tool, and that a bearing (D) is arranged between the stator ( 20 ) and the fastening ring ( 50 ),

wherein the fastening ring ( 50 ) for the attaching of a work tool is separately journalled relative to the stator ( 20 ) independently of a bearing (B, C) between the stator ( 20 ) and the rotor ( 30 ), and

a driver ( 80 ; 180 ; 280 ) for transferring the rotational movement of the rotor ( 30 ) to the fastening ring ( 50 ),

wherein the driver ( 80 ) is movable laterally relative to the rotor ( 30 ), or the fastening ring ( 50 ), or both, in order to eliminate stressing conflict between the bearings (B,C) between the stator ( 20 ) and the rotor ( 30 ), and

at least one radially outwardly extending tab on said driver received in at least one corresponding recess in said fastening ring, and at least one radially inwardly extending tab on said driver received in at least one corresponding recess in said rotor, said radially outwardly and inwardly extending tabs and corresponding recesses being arranged to enable lateral movement of said driver relative to said rotor, or said fastening ring, or both.

2. The arrangement according to claim 1 , characterized in that said driver ( 80 ) is in engagement with the rotor ( 30 ) and the fastening ring ( 50 ) in such a manner that the rotational movement of the rotor is transferred to the fastening ring.

3. The arrangement according to claim 2 , characterized in that the engagement of the driver with the rotor ( 30 ) and/or the fastening ring ( 50 ) is provided with gaps in order to eliminate the transfer of force not related to torque transfer.

4. A rotator ( 10 ) comprising a stator ( 20 ) and a rotor ( 30 ), wherein the rotator ( 10 ) comprises a fastening ring ( 50 ) for attaching a work tool, a bearing (B, C) between the stator ( 20 ) and the rotor ( 30 ), and a bearing (D) between the stator ( 20 ) and the fastening ring ( 50 ),

said rotator further comprising a driver ( 80 ; 180 ; 280 ) arranged in a space between the fastening ring ( 50 ) and the rotor ( 30 ) for transferring the rotational movement of the rotor ( 30 ) to the fastening ring ( 50 ), wherein the driver comprises at least one of:

at least one inner tab ( 83 , 84 ) arranged to cooperate with a recess ( 93 , 94 ) defining a slot in the rotor ( 30 ), and

at least one outer tab ( 81 , 82 ) arranged to cooperate with a recess ( 91 , 92 ) defining a slot in the fastening ring ( 50 ).

5. The rotator as claimed in claim 4 , wherein said inner or outer tab on the driver and the recess in said rotor or said fastening ring are arranged so as to couple said driver, said fastening ring, and said rotor together to enable lateral movement of said driver relative to said rotor, or to said fastening ring, or to both.

6. The rotator as claimed in claim 5 , wherein the driver ( 80 ) is movable laterally relative to the rotor ( 30 ), or the fastening ring ( 50 ), or both, to eliminate stressing conflict between the bearings (B,C) between the stator ( 20 ) and the rotor ( 30 ).

7. A rotator, which rotator comprises a stator and a rotor, wherein the rotator comprises a fastening ring for attaching a work tool, and that a bearing is arranged between the stator and the fastening ring, said bearing being arranged to transfer forces acting between a rotatable work tool and the stator, wherein

a driver is in engagement with the rotor and the fastening ring in such a manner that the rotational movement of the rotor is transferred to the fastening ring, wherein

the driver comprises at least one inner tab arranged to engage with at least one recess in the rotor, or at least one outer tab arranged to engage with at least one recess in the fastening ring, or both; and

the respective tabs and recesses are configured such that a gap is defined between the inner tab of the driver and the rotor when the inner tab of the driver is received in the recess of the rotor, or a gap is defined between the outer tab of the driver and the fastening ring when the outer tab of the driver is received in the recess of the fastening ring, or both, for eliminating the transfer of force not related to torque transfer.