Rotation unit for torque tong comprising a gripping cylinder

1. A rotation unit for a torque tong, comprising:

a fixed part, said fixed part including at least one gripping cylinder directly mounted thereto; and

a rotary part designed to grip a pipe to be rotated, said rotary part comprising:

at least one movable gripping jaw mounted directly to the rotary part, the at least one movable gripping jaw being movable into engagement with the pipe, the at least one movable gripping jaw being rotatable with the rotary part to be in alignment with the at least one gripping cylinder,

wherein the at least one gripping cylinder is directly engageable with the at least one movable gripping jaw to move the at least one movable gripping jaw into engagement with the pipe, when the at least one movable gripping jaw is rotated to be aligned with the at least one gripping cylinder so that the at least one gripping cylinder can displace the at least one movable gripping jaw.

2. The unit according to claim 1 , wherein the rotary part further comprises at least one holding cylinder arranged to maintain the engagement between the at least one movable gripping jaw and the pipe after the at least one movable gripping jaw has been moved to engage the pipe.

3. The unit according to claim 2 , wherein the at least one holding cylinder is connected to a valve arranged to selectively prevent hydraulic fluid from flowing out of the at least one holding cylinder and allow hydraulic fluid to flow out of the at least one holding cylinder.

4. The unit according to claim 3 , wherein the valve can be operated by means of an actuator disposed on the fixed part, the actuator being arranged to operate the valve independently of the position of the rotary part.

5. The unit according to claim 2 , wherein the at least one holding cylinder is hydraulically connected to at least one slave cylinder on the rotary part, and a master cylinder on the fixed part is arranged to actuate the at least one slave cylinder when the master cylinder is operatively engaged with the at least one slave cylinder.

6. The unit according to claim 2 , wherein the at least one holding cylinder is connected to an accumulator arranged to provide hydraulic pressure to the at least one holding cylinder for disengaging the at least one movable gripping jaw from the pipe.

7. The unit according to claim 2 , wherein the at least one holding cylinder is equipped with a return spring arranged to act on the at least one holding cylinder to disengage the at least one movable gripping jaw from the pipe.

8. The unit according to claim 2 , wherein the at least one holding cylinder is connected to a closed hydraulic system on the rotary part.

9. The unit according to claim 8 , wherein the closed hydraulic system comprises an accumulator arranged to provide pressure for return of a slave cylinder, said slave cylinder being hydraulically connected to the at least one holding cylinder, so that hydraulic fluid may flow from the at least one holding cylinder to the slave cylinder.

10. The unit according claim 2 , wherein the at least one holding cylinder is disposed or integrated inside the at least one movable gripping jaw or a support for the at least one movable gripping jaw.

11. The unit according to claim 1 , wherein the at least one gripping cylinder acts on a protrusion on the at least one movable gripping jaw.

12. The unit according claim 1 , wherein there are from one to six of the at least one movable gripping jaw.

13. The unit according to claim 12 , wherein there are three of said at least one movable gripping jaw and three of said at least one gripping cylinder.

14. The unit according to claim 1 , wherein the at least one movable gripping jaw is adjacent to and aligned with the at least one gripping cylinder when the at least one gripping cylinder engages the at least one movable gripping jaw.

15. The unit according to claim 1 , wherein the at least one gripping cylinder acts on an arm, the arm being connected to a tappet, the tappet being arranged to exert a force against the at least one holding cylinder when the tappet is rotated from a first position to a second position.

16. A rotation unit for a torque tong, comprising:

a fixed part, said fixed part including at least one gripping cylinder directly mounted thereto; and

a rotary part designed to grip a pipe to be rotated, said rotary part comprising:

at least one movable gripping jaw arranged to be moved into engagement with the pipe; and

at least one holding cylinder arranged to maintain the engagement between the at least one movable gripping jaw and the pipe after the at least one movable gripping jaw has been moved to engage the pipe,

wherein the at least one gripping cylinder is arranged to move the at least one movable gripping jaw into engagement with the pipe, by operatively engaging the at least one movable gripping jaw when the at least one movable gripping jaw is located operatively opposite the at least one gripping cylinder so that the at least one gripping cylinder can displace the at least one movable gripping jaw, and the at least one gripping cylinder acts on an arm, the arm being connected to a tappet, the tappet being arranged to exert a force against the at least one holding cylinder when the tappet is rotated from a first position to a second position.

17. A rotation unit for a torque tong, comprising:

a fixed part; and

a rotary part designed to grip a pipe to be rotated, said rotary part comprising:

at least one movable gripping jaw arranged to be moved into engagement with the pipe; and

at least one holding cylinder arranged to maintain the engagement between the at least one movable gripping jaw and the pipe after the at least one movable gripping jaw has been moved to engage the pipe,

wherein the fixed part comprises at least one gripping cylinder arranged to move the at least one movable gripping jaw into engagement with the pipe when the at least one movable gripping jaw is operatively engaged with the at least one gripping cylinder, and

wherein the at least one gripping cylinder acts on an arm, the arm being connected to a tappet, the tappet being arranged to exert a force against the at least one holding cylinder when the tappet is rotated from a first position to a second position.