GRIPPER WITH SPINNING MEANS

GRIPPER WITH SPINNING MEANS

The invention relates to a gripper for gripping and spinning a pipe body. More specifically the invention relates to a gripper comprising a rotatable input shaft, gripping means for gripping said pipe body and spinning means for spinning said pipe body while it is being gripped by said gripping means. The invention also relates to a system for moving, gripping and spinning a pipe body, as well as to a method for moving, gripping and spinning pipe bodies.

Handling of pipe bodies, such as pipes and so-called subs, crossovers, kelly cocks, bottom hole assemblies, etc., may be a challenge on a rig floor. To connect or disconnect such pipe bodies from a pipe string it is today common to use a combination of manual work and machinery. One machine is typically used for lifting the pipe body while another machine is used to spin the pipe body so as to connect it to the drill string. The involvement of two different machines makes the work time consuming and the involvement of manual work together with heavy machinery is a potential safety risk.

Grippers are known that combine gripping functionality with spinning functionality. Some relevant grippers from the prior art are disclosed in the following patents and patent applications:

- WO 2004/079147 A2;

- US 2009/053014 Al;

- US 2013/283589 Al; and

- US 3,892,148.

Grippers with spinning means according to the prior art typically take up a lot of space and have a limited possibility of rotational and translational movement. The gri pping means and the spinning means are often driven via separate input shafts that take up space and limit the potential freedom of movement of the gripper. Grippers according to the prior art are also typically provided with a plurality of cables, wires etc. to provide sufficient power and control of the gripper, such cables and wires are also limiting the freedom of movement and constituting a potential security risk in explosion- exposed areas, such as on a drilling rig.

The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to prior art.

The object is achieved through features, which are specified in the description below and in the claims that follow.

The invention is defined by the independent patent claims. The dependent claims define advantageous embodiments of the invention.

In a first aspect the invention relates to a gripper for gripping and spinning a pipe body, the gripper comprising :

- a rotatable input shaft;

- gripping means for gripping said pipe body; and

- spinning means for spinning said pipe body while it is being gripped by said gripping means, wherein the gripper further comprises a coupling means for connecting said rotatable input shaft to said gripping means and to said spinning means and for selectively engaging said gripping means and said spinning means.

In a preferred embodiment, said coupling means may comprise a differential coupling means. A differential coupling means in the form of a differential gear may allow one rotatable input shaft to be used to operate both the gripping means and the spinning means. The power from the rotatable input shaft may thus be distributed in what may be regarded as two branches, wherein one branch provides power to the gripping means, whereas the other branch provides power to the spinning means. The gripper may be adapted to operate one of the branches at a time, for instance by selectively locking one of the branches of the differential coupling as will be described more in detail below, and which will be more easily understood with reference to the exemplary embodiment shown in the figures.

In an alternative embodiment, the coupling means may comprise a clutching means for selectively engaging and disengaging said gripping means and said spinning means. The selective engagement of said gripping means and said spinning means may for instance be realized by means of two interacting clutches.

The invention according to the first aspect solves all of the above-mentioned disadvantages of the prior art, in that one and the same tool, the gripper, may be used both to grip and spin pipe bodies. At the same time, the one rotatable input shaft ensures that the gripper may be connected to a conveying means, such as a robot, while still allowing for full rotational and translational freedom for the gripper. The gripper is at the same time very compact and easily handled.

In one embodiment the gripper may further comprise braking means for engaging said differential coupling means so as to selectively prevent said gripping means and said spinning means from being operated upon rotating said rotatable input shaft. This may be advantageous so as to disable one of the two functionalities, i.e. gripping or spinning, while enabling the other functionality. The braking means may engage one of the two branches of the differential coupling means at time, and the braking means may comprise one brake or it may comprise several independently operatable brakes. The brakes may preferably be of an electromechanical type. In the alternative embodiment where the coupling means comprises clutching means, one clutch may replace the differential gear itself, while one clutch may replace a brake connected to one of the branches.

In one embodiment the gripper may comprise inductive coupling means for receiving wireless power and/or communication from an external source. This means that power and communication may be transferred wirelessly from an external source, implying that the gripper may be connected to and operated from an external component, a conveying means, without the need for wired and cabled connections. This may also make possible the use of a gripper according to the first aspect of the invention in explosion-exposed areas, i.e. to EX certify the gripper. It may thus be advantageous if electronic components in the gripper are provided in an encapsulated chamber of the gripper, such as in an oil-filled chamber. The communication from the source to the gripper may be bi-directional, also enabling feedback from the gripper.

In a particularly useful embodiment said inductive coupling means may be connected to said differential coupling means for selectively engaging said gripping means and said spinning means. The power and communication transferred to the gripper may for instance be utilized to engage or disengage the above-mentioned braking means so as to choose which function, gripping or spinning, to use. The data communication may be bi-directional. In one preferred embodiment the inductive coupling means may be such as developed and offered by the Norwegian company Wireless Power and Communication (WPC). Reference is made to WPC's European patent no. 1741113 for an in-depth description of wireless power and data communication transfer.

The spinning means may be one or more active rollers, though the invention is not to be construed as limited to rollers as many alternative spinning means, such as various circulating endless belts and chains, may also be used. In one particularly useful embodiment, gearing means, connecting said active rollers to said differential coupling means, may be provided inside said one or more active rollers. This may be advantageous for providing sufficient gearing for the rollers while at the same time saving significant space in the gripper, implying that the gripper may be made even more compact and thus becomes even more easily handled.

In one embodiment the gripping means may be provided with one or more passive rollers. This may be advantageous for ensuring smooth, substantially friction-less spinning of a pipe body while it is being held by the gripper.

In one embodiment the gripping means may be adapted to securely hold pipes of different diameters. This may be realized by providing the gripper with gripping means as disclosed in US patent 8,419,097 assigned to the present applicant. Alternatively, the possibility of securely gripping pipes of different diameters may also be realized by supporting gripping arms of the gripping means in eccentric bearings as disclosed in WO 2013/036134 A2.

In one embodiment the gripper may further comprise connecting means for selectively connecting said gripper to a gripper conveying means. The connection means may connect the gripper input shaft to an output shaft on the conveying means, as well as provide an interface between the gripper and the gripper conveying means. The connection means may comprise a connection flange.

In one embodiment the gripper may be provided with biasing means for biasing the gripping means towards a pipe body or for biasing the pipe body towards the gripping means also when the gripping functionality is disabled, for instance when the pipe body is being held and moved including when the spinning functionality is enabled. This will ensure a good grip around the pipe body also when the gripping functionality is disabled, such as when a braking means locks the gripping function. In one embodiment the biasing means may be a torsion spring or the like directly or indirectly connected to the gripping means. The torsion spring may be included in a gearing stage connecting the rotatable input shaft to the gripping means. Alternatively, the biasing means may be connected to the spinning means, such as the active rollers, so as to bias the spinning means towards the pipe body.

In a second aspect the invention relates to a system for gripping, moving and spinning a pipe body, the system comprising :

- a gripper according to the first aspect of the invention; and - a gripper conveying means provided with a rotatable output shaft connectable to said rotatable input shaft of the gripper.

The conveying means may thus be used to move the gripper on an operation site, such as on a rig floor. It may be used to move the gripper between a storage location for pipe bodies and a well centre. In particular, the one rotatable input shaft, which is connectable to a rotatable output shaft on the gripper conveying means may allow for a full translational and rotational freedom for the gripper on the gripper conveying means. The gripper conveying means may thus be a robot, preferably with a plurality of joints and rotation axes and with translational freedom. The system may be provided with a control unit for operating the gripper and the gripper conveying means a utomatically or semi-automatically. The control unit may be provided internally or externally from the gripper conveying means.

In a preferred embodiment of the system the gripper conveying means may be provided with inductive coupling means for transferring power and/or communication to said gripper. The communication may be bi-directional. Typically, inductive coupling means on the gripper may be brought into proximity with the inductive coupling means on the gripper conveying means upon connecting the rotatable input shaft on the gripper to the rotatable output shaft of the gripper conveying means so as to allow for wireless transfer of power and/or communication between the gripper and the gripper conveying means. The connection between the gripper and the gripper conveying means may thus include a rotatable shaft but without the need for any wires, cables, etc., which may be beneficial for ensuring freedom of rotation and translation as well as for making the system explosion (EX) proof, for instance allowing use of the system in areas where there is a danger of gas ignition. Electronic components of the gripper may be provided in an encapsulated chamber as discussed above. The interface between the gripper and the gripper conveying means may thus be provided as a sealed flange covering the shaft connection and the inductive coupling means.

There is also described a drilling rig provided with a system according to the second aspect of the invention.

In a third aspect the invention relates to a method for gripping, moving and spinning a pipe body by means of a system according to the second aspect of the invention, the method comprising the steps of:

- connecting said rotatable output shaft of the gripper conveying means to said rotatable input shaft on said gripper; - selectively engaging said gripping means so as to grip a pipe body; and

- selectively engaging said spinning means so as to spin said pipe body.

The method may further comprise the step of moving said pipe body from a storage location to an operation location by means of said gripper conveying means. The operation location may be over a well centre.

The method may further comprise the step of spinning the pipe body so as to connect or disconnect said pipe body to or from a pipe string. After the pipe body has been connected to a pipe string, the method may also comprise the steps of:

-selectively engaging said gripping means so as to release said pipe body from the gripper; and

- disconnecting said rotatable output shaft of the gripper conveying means from said rotatable input shaft of the gripper.

This implies that the gripper conveying means may selectively disconnect from the gripper. The gripper conveying means may for instance place the gripper in a tool magazine. From the tool magazine the gripper conveying means may connect to another gripper according to the invention or it may even connect to a completely different tool adapted to perform a different operation. The connection means, i.e. the connection interface between the gripper conveying means and the gripper may be standardized so that a plurality of different tools may be connectable to the gripper conveying means.

In the following is described an example of a preferred embodiment illustrated in the accompanying drawings, wherein :

Fig. 1 shows, in a perspective view, a gripper according to the present invention;

Fig. 2 shows, in a top view, the gripper from Fig. 1 ;

Fig. 3 shows, in a side view, the gripper from Fig. 1;

Fig. 4 shows, in a cross-sectional view, the gripper as seen through the line A-A from Fig. 2;

Fig. 5 shows, in a cross-sectional view, the gripper as seen through the line B-B from Fig. 2;

Fig. 6 shows, in a cross-sectional view, the gripper as seen through the line C-C from Fig. 3; Fig. 7 shows, in a cross-sectional view, the gripper as seen through the line D-D from Fig. 3;

Fig. 8 shows, in a cross-sectional view, the gripper as seen through the line F-F from Fig. 2;

Fig. 9 shows, in a cross-sectional view, the gripper as seen through the line E-E from Fig. 3;

Fig. 10 shows, in a top view, the gripper from Fig. 1 holding a small diameter pipe;

Fig. 11 shows, in a top view, the gripper from Fig. 1 holding a large diameter pipe;

Fig. 12 shows, in a perspective view, a drilling rig comprising a system according to the invention; and

Fig. 13 shows, in a large scale, the system from Fig. 12.

In the following the reference numeral 1 will indicate a gripper according to the first aspect of the invention, whereas the reference numeral 10 will indicate a system according to the second aspect of the invention. Identical reference numerals refer to similar or identical features. The figures may be shown slightly simplified and schematic and the different features on the figures are not necessarily drawn to scale.

Figures 1-3 show a gripper 1 according to the invention. The gripper 1 is provided with a housing 2, to which both gripping means 3 and spinning means 5 are connected. In a normal position of use, the housing 2 covers most of the parts constituting the gripper 1. These parts will be visible with reference to the following cross-sectional drawings. The gripping means 3 is provided in the form of two sets of gripping arms 31a . The gripping arms 31a are driven by drive arms 31b, rotatable around rotation axes 31e, and connected by link arms 31c, the link arms being connected to the gripper housing 2 at a rotation axis 31d . The functionality of the gripping means 3, which allows gripping of pipes and other objects of various diameters, was disclosed in the applicant's own patent US 8,419,097 to which reference is made for an in-depth description of the gripping means 3. The spinning means 5 comprises active rollers 51a, 51b. When holding a pipe body 11, see figures 10 and 11, in the gripping arms 31a, track rings 51c on the active rollers 51a, 51b will engage the pipe body 11 so that the pipe body 11 is spun with the active rollers 51a, 51b. The gripping arms 31a are fur- ther provided with passive rollers 34 in order to ease the rotation of a pipe body 11 held in the gripper arms 31a. The gripper 1 is provided with a flanged interface 23 forming a connecting means for a conveying means 14, see Figs. 12 and 13, as will be described more in detail below with reference to the following figures. Figures 2 and 3 show the gripper 1 in a top view and in a side view, respectively.

Reference is now made to Figures 4-9, which are various cross-sections taken from Figures 2 and 3. An input shaft 9, with shaft connection 91, is connected to a differential coupling means 6, which will be described in the following. The input shaft 9 is connected to a first differential gear 6a further connected to a differential spider gear 6c which in turn is connected to a differential housing 6d and to second differential gear 6d, as can be best seen in Figures 5 and 6. The differential coupling means 6 divides input power from the rotatable input shaft 9 into what may be described as two branches, wherein one branch provides the gripping function while the other branch provides the spinning function. In the shown embodiment, the gripping function is activated upon rotation of the differential housing 6, while the spinning function is activated by rotation of the second differential gear 6d. For transferring the power as effectively as possible, the gripper 1 is provided with breaking means 7 selectively disabling one of the two branches so that the input power may be supplied to either the gripping means 3 or to the spinning means 5. In the shown embodiment the breaking means 7 comprises a first break 7a in the form of an electromechanical holding brake and a second brake 7b in the form of a solenoid actuator, see Figure 8, both energizable and controllable via inductive coupling means 13 as will be described more in detail below. For activating the gripping means 3, the inductive coupling means 13 will energize the holding brake 7a to prevent the second differential gear 6b from rotating thereby disabling the spinning function. As the second differential gear 6b is blocked, the first differential gear 6a and the spider gear 6c will set the differential housing 6d in rotation, if possible. The solenoid actuator 7b, which is best seen in Figure 8, pulls a lever arm 77 connected to a ratchet mechanism 73. The ratchet mechanism 73, when energized by the solenoid actuator 7b, is freed from its engagement with a ratchet wheel 71, thus allowing the ratchet wheel 71 to be rotated. In its idle state, the ratchet 73 mechanism is biased by means of a not shown spring so as to prevent the ratchet wheel 71 from rotating, thereby disabling the gripping function as will be explained in the following. The inductive coupling means 13 activates the solenoid actuator 7b, thus allowing the ratchet wheel 71 to rotate. The ratchet wheel 71 is connected to a first spur gear 59, the first spur gear further being connected to a second spur gear 59a and third spur gear 59b, as best seen in Figures 7 and 8. The second spur gear 59a is connected to a hypoid gear pinion 47a, the hypoid gear pinion 47a further being connected to a hypoid gear 48a, as can be best seen in Figure 4. The hypoid gear 48a is further connected to a sun gear 49a engaged with a planet gear stage 53a including a stationary ring gear. Finally the planet gear stage 53a is driving a first drive shaft 55a, the drive shaft 55a having an axis of rotation coinciding with the rotation axis 31e and the drive shaft being connected to and being able to drive the drive arms 31b for moving the gripper arms 31a. The third spur gear 59b has similar connections, i.e. driving a hypoid gear pinion 47b, in turn driving a second drive shaft 55b. The above description describes one embodiment of the mechanisms involved for activating the gripping means 3. The gripping force may be controllable by measuring torque on a motor driving the input shaft 9. The motor may be provided in the gripper conveying means 14 as will be discussed below.

In a second position of use, typically when a pipe body 11 has already been gripped by the gripper 1, the spinning means 5 may be activated. The gripping function is then disabled by deactivating the solenoid actuator 7b. The biasing spring will then force the ratchet mechanism 73 into engagement with the ratchet wheel 71, thus locking the differential housing 6d and thereby disabling movement of the gripping arms 31a. At the same time, the holding brake 7a is deactivated so that the second differential gear 6b becomes free to rotate. The input shaft 9 is connected to the second differential gear 6b via the first differential gear 6a and the differential spider gear 6c. The second differential gear 6b is connected to a bevel gear pinion 38, the bevel gear pinion driving a bevel gear shaft 39, as best seen in Figures 5 and 6. The bevel gear shaft 39 is connected with a first chain wheel 43a and a second chain wheel 43b. The first chain 43a wheel is further connected to a third chain wheel 45a via a chain 41, as best seen in Figure 9. The third chain wheel 45a is connected to a roller sun gear 33a further connected to a plurality of roller planet gears 32a, as can be best seen in Figure 6. The roller planet gears 32a engage with the active roller 51b. The second chain wheel 43b is similarly connected to a fourth chain wheel 45b similarly driving the first active roller 51a, the first and second active rollers 51a, 51b constituting the spinning means 5. Each active roller 51a, 51b is provided with two track rings 51c held in place by locking nuts 51d, the track rings 51c providing the necessary friction for a pipe body 11 held in the gripping arms 31a to be rotated.

Figures 10 and 11 show the gripper 1 holding a small diameter pipe 11 and a large diameter pipe 11, respectively. Once again reference is made to US 8,419,097 for an in-depth description of the functionality of the gripping means 3.

Figures 12 and 13 show a drilling rig 27 where a system 10 according to the second aspect of the invention is provided on the rig floor 29. The system 10 comprises a conveying means 14 in the form of a robot, which is best seen in the enlarged view in Figure 13. The robot 14, which will not be discussed in detail herein, has six rotational axes and is also adapted to be translated along a track 28 as indicated in the figures. The drilling rig 27 is further provided with a tool magazine 24 provided with a plurality of tools 26, including one or more grippers 1 according to the invention. The robot 14 approaches the tool magazine 24 and connects to the gripper 1. A tool interface 23' on the robot 14 fits complimentary to the flanged tool interface 23 on the gripper 1. A rotatable output shaft 19 on the robot connects to the shaft connection 91 on the ro- tatable input shaft 9 on the gripper 1. Upon connecting the gripper 1 to the robot 14, inductive coupling means 13' on the robot is brought into proximity with the inductive coupling means 13 on the gripper, thereby enabling wireless transfer of power and communication to the gripper, and also feedback communication from the gripper 1 to the robot 14. The tool interfaces 23, 23' and the rotatable input and output shafts 9, 19 constitute the connecting means of the gripper 1 and the robot 14. The connecting means is provided as a standardized tool interface allowing the robot 14 to connect and disconnect to and from each of the tools 26 in the tool magazine 24. The rig floor is also provided with a storage area 22 for pipe bodies 11. The robot 14, connected to the gripper 1, is translated along the track 28 to approach the storage area 22 to grip a pipe body 11. The robot 14 may further move the pipe body 11 on the rig floor 29, such as to a well centre 20 in order to spin the pipe body 11 into a not shown pipe string. It should also be noted that the system 10 in the shown embodiment is controllable by means of a control unit 25 provided in the robot. The control unit 25 may receive instructions from an operator to have the system perform a certain task, whereby the control unit 25 activates the robot to pick up a preferred tool, which according to this embodiment is a gripper 1. The control unit also activates or deactivates the power supply via the inductive coupling means 13, 13' and the control unit 25 starts and stops a not shown motor provided in the robot 14 to operate the gripper 1 by rotating the rotatable input shaft 9 as described above.

It should be noted that the above-mentioned embodiment illustrates rather than limits the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In particular, a person skilled in the art would be able to construct the gearing from the differential coupling means to the gripping means and to the spinning means in a variety of different ways without departing from the scope of the invention. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of ele- merits or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.