NO20170339A1

NO20170339A1 - Gripping block arrangement and method of use

Info

Publication number: NO20170339A1
Application number: NO20170339A
Authority: NO
Inventors: Bernt Olav Holen; Tine Sæbø
Original assignee: Mhwirth As
Priority date: 2014-08-12
Filing date: 2017-03-08
Publication date: 2017-03-08
Also published as: US20170241217A1; GB201703692D0; GB2544019A; WO2016024865A1; GB2544019B

Description

GRIPPING BLOCK ARRANGEMENT AND METHOD OF USE

The present invention relates to a gripping block, a holding device for a gripping block, and a method for replacing a gripping block from the holding device. The invention is particularly applicable with so-called gripping tongs or gripping claws used in connection with pipe handling. Such devices are used particularly for handling and/or moving pipes between different stations on a deck of a drilling vessel.

Background

From prior art in other fields offshore, in particular in connection with so-called torque tongs, power tongs and iron roughnecks used during assembly of drill pipe used in the drilling of wells for hydrocarbons (oil and gas), it is common to use such tongs to connect lengths of drill pipe together and/or separate them. Generally, an upper pipe section is rotated, while a lower section of pipe/tubing is held in a fixed position. Gripping blocks provide a sufficient friction against the pipe so that the pipe is held in the torque tong during connection with other pipe sections. The gripping blocks are therefore subjected to large forces and must be replaced regularly because of wear. An example of an iron roughneck comprising such gripping blocks is shown in Norwegian Patent No. 319959 Bl, in which there is mounted a gripping block on each of three displaceable clamping devices. Each gripping block is equipped with a plurality of relatively sharp grooves which are clamped against the pipe and thereby grip this.

From Norwegian patent application 20092552 there is known a removable gripping block for torque tongs / power tongs. Disclosed is a holding device for a gripping block, wherein said holding device comprises a body comprising a longitudinal slot håving internal walls to engage the corresponding surfaces on the gripper, wherein a first wall is movable between a retracted position in the slot, where the gripper is released, and a forward position the slot, where the gripper is clamped in abutment against the interior walls.

It has been found that known gripping blocks have a tendency to become stuck, and that they can be difficult to replace when worn. The slot and the gripping block of the prior art must be designed with the least possible "play" or clearance between them, to ensure that the gripping block is securely fixed in the slot. This is not necessarily compatible with the harsh environment in which the device operates, i.e. an environment with a lot of pollution from oil, dirt, dust, corrosion, etc, which can cause the small clearances in the slot from becoming clogged and jamming the gripping block. This may result in the gripping blocks being stuck when they need to be replaced, resulting in extra time required for replacement, with the gripping blocks håving to be hammered or knocked out, etc.

The design of traditional gripping blocks requires the gripping block holding device to have a matching, machined slot to hold the gripping block in place, resulting in the holding device being expensive to produce.

There is therefore a need for an improved holding device for easier change of gripping blocks, which remedy or reduce at least one of the disadvantages of the prior art.

An object of the invention is therefore to provide a gripping block and a holding device for a gripping block which saves time and eases the work associated with the replacement of the gripping blocks.

This is achieved with the invention as defined in the independent claims. The dependent claims describe other characteristic of the invention.

Summary of the invention

The present invention relates to a gripping block, such as a removable gripping block, which can be used in gripping claws, grip holders, torque tongs, power tongs or any other device used for pipe handling offshore or on land. Furthermore, the invention relates to a holding device for a gripping block, and a method for replacement of a gripping block in a holding device.

According to the present invention there is provided a gripping block comprising a rear side, a front side and two opposite side faces, wherein at least a portion of the rear side is adapted to lie in abutment against an inner wall of a slot formed in a holding device for the gripping block, and wherein the front side of the gripping block at least over a part of its outer surface is designed with friction generating means, wherein the gripping block is further designed such that a largest width of the rear side has a shorter longitudinal extension than the smallest width of the front side of the gripping block.

The friction generating means may be formed in the gripping block itself, such as serrations, grooves or equivalent, or the friction generating means can also be attached to the gripping block front side in a suitable way. This will be known to the skilled person and therefore not described further herein.

In one embodiment, at least one portion of the gripping block forward side may be formed convex relative to the gripping block rear side, so as to provide a curved contact surface for the pipe to be gripped. The friction generating means may then be formed in this convex area.

In order to keep the gripping block fixed in the holding device, the gripping block may be formed with an upper and lower flange, where each of the flanges may be provided as an extension of the gripping block rear side. One flange can then be designed to be placed in a recess in the holding device, while the other flange may be designed to form a construction for a locking member.

In one embodiment, the gripping block may be designed such that the angle formed between each side face and the rear side of the gripping block is obtuse. It should be understood that the angle between each side face and the rear side of the gripping block may also be 90 degrees, whereby each side face will then be arranged perpendicular to the rear side of the gripping block. An obtuse angle is defined according to the present invention to be an angle greater than 90 degrees and less than 180 degrees.

According to the present invention there is also provided a holding device for a gripping block, which holding device comprises a body which is formed with a slot, wherein the slot comprises an inner wall which is adapted to form an abutment

against a rear side of the gripping block, when the gripping block is arranged in the holding device, and two opposite side surfaces, which side surfaces are arranged on either side of the inner wall, which side surfaces are shaped complementarily to the side faces of the gripping block, whereby each side surface and the inner wall may create an obtuse angle, or may be arranged perpendicular to each other . The holding device is further provided with a recess adapted for receiving a lower flange of the gripping block and a locking member for locking against an upper flange of the gripping block.

It should be understood that the holding device can also be formed with a recess adapted to receive an upper flange of the gripping block, whereby the locking member is then used to lock onto a lower flange of the gripping block.

The holding device may be further configured with a plurality of bores for receiving suitable fastening means for attachment of the locking member. Similarly, the holding device may be formed with a plurality of bores for receiving suitable fastening means for attachment of the holding device to a torque tong or the like.

The bores used for the locking member and/or attachment of the holding device to a torque tong or the like can be formed as threaded holes, in which case the attachment means may be screws. A skilled person will understand, however, that the holes may be formed in other ways and that the fasteners can be bolts or similar, whereby this is not further described herein.

According to the present invention there is also provided a method for replacing a gripping block, where the method may include the steps of first loosening the attachment means from the locking part and removing the locking member from the holding device, so as to gain access to the gripping block. Then the gripping block is removed from the slot, either being tilted out or lifted out of the recess. A new gripping block may then be inserted into the holding device, where this is done by inserting the new gripping block in the slot and then sliding the gripping block downwards relative to the holding device, so that the lower flange is pushed into the recess in the holding device, so as to prevent that the gripping block can be tåken out horizontally from the holding device. The locking member is then placed back over the gripping block upper flange, and the fasteners used to attach the locking member to the holding device.

Brief Description of the Figures

A non-limiting embodiment of the invention will now be described with reference to the accompanying figures wherein like parts are given like reference numerals, and in which: Figure 1 shows an example of an arrangement of the gripping block and the holding device according to the present invention; Figure 2A shows a holding device and a gripping block according to the present invention, seen from the side and obliquely from above; Figure 2B shows a front view of the holding device and the gripping block of Figure 2A; Figure 2C shows a holding device and gripping block according to the present invention, seen from above; Figure 2D shows a sectional, side view through the center of the holding device with gripping block; Figure 3A shows a gripping block of the present invention, seen from above;

Figure 3B shows a front view of the gripping block of figure 3 A; and

Figure 3C shows the gripping block of figure 3A, seen from the side.

Description of an embodiment of the invention

Figure 1 shows a lifting arrangement 24, exemplified as an iron roughneck, with which a gripping block and a holding device for a gripping block according to the present invention may be used. The lifting arrangement 24 may comprise a number of arms with gripper claws in their outer ends, for lifting and/or handling of one or more pipes. Figure 2A shows a holding device 2 and a gripping block 1 according to the present invention, seen partly from the side and obliquely from above. The holding device 2 is, at least over a part of the holding device's 2 height, provided with a slot 4, which slot 4 comprises an inner wall 5 engaging a rear side 6 of the gripping block 1, as

well as two opposing side surfaces 7, 8 arranged at each side of the inner wall 5, which side surfaces 7, 8 are complementarily shaped relative to side faces 9, 10 of the gripping block 1. Each of the side surfaces 7, 8 forms an obtuse angle Øi with the inner wall 5. The holding device 2 is further, towards its lower end, in the part of the holding device 2 which is not formed with the slot 4, formed with a recess 20 extending in the holding device's 2 longitudinal direction, to form an angled flange 16 for receiving a lower flange 12 of the gripping block 1.

When mounting the gripping block 1 in the holding device 2, the gripping block 1 is positioned into the slot 4 from above and is then pushed down in the holding device 2 so that a lower flange 12 of the gripping block 1 is received in the recess 20, until the angled flange 16 prevents a horizontal rem oval of the gripping block 1 from the recess 20. Then the gripping block 1 is locked in the holding device 2 by placing an upper locking member 19 from above, the locking member 19 also is formed with an angled flange 16, which would prevent both vertical and horizontal movement of the gripping block 1 in the slot 4. The locking member 19 is attached to the holding device 2 with suitable fasteners 17, 18, such as for example screws or bolts 17, 18, either from above (as shown in Figures 2A-2D) or perpendicular to the holding device 2. The locking member 19 locks the gripping block 1 in the slot 4 at the upper flange 13 of the gripping block 1 so that the rear side 6 of the gripping block 1 abuts against the inner wall 5, while the lower flange 12 of the gripping block 1 is disposed in recess 20 and kept in place of the angled flange 16.

Figure 2B shows the holding device 2 and the gripping block 1 according to the present embodiment of the invention, seen straight from the front, while Figure 2C shows the holding device 2 and the gripping block 1 seen from above.

The holding device 2 may be formed with means 21 for attachment to a torque tong or the like, for example through screws, bolts or equivalent 21. The holding device 2 will then be formed with a plurality of bores 22. Furthermore, the holding device 2, or alternatively the gripping block 1, may be formed with one or more slots or other suitable means (not shown) for manual rem oval of the gripping block 1, using a flat screwdriver, a crowbar or the like, to facilitate replacement of the gripping block 1. Figure 2D shows a sectional view through the center of the holding device 2 with gripping block 1 seen from the side. Figure 3A shows a gripping block 1 according to the present invention seen from above. The gripping block 1 has a rear side 6, a front side 11 and two opposing side faces 9, 10. The rear side 6 is adapted for abutment against an inner wall 5 in a slot 4 in a holding device 2. The front side 11 is formed with friction generating means 15 over at least part of its outer surface. The friction generating means 15 has a convex shape relative to the rear side 6 of the gripping block 1. This achieves the best possible grip around a pipe or tubular body which is held in, for example, a torque tong in which said holding device 2 is mounted.

As shown in the figure, the rear side 6 has a shorter longitudinal extent than the front side 11 of the gripping block 1. This makes it easier to remove and insert the gripping block 1 in the holding device 2, since it is only the lower flange 12 and the upper flange 13 which holds the gripper 1 in the slot 4, respectively by the angled flange 16, the holding device 2 and locking member 19. If the locking member 19 is released, only the recess 20, with the angled flange 16, will hold the gripping block 1 in the holding device 2.

The angle Øi between each of the two side faces 9, 10 and the rear side 6 is obtuse, i.e., Øi> 90°.

Figure 3B shows the gripping block 1 according to the present invention, seen straight from the front.

The gripping block 1 is formed with a lower flange 12 and an upper flange 13. The lower flange 12 and the upper flange 13 are disposed in extension in opposite directions of the rear side 6 of the gripping block 1, respectively.

Figure 3C shows the gripping block 1 according to the present invention seen from the side.

The embodiment described herein and exemplified in the figures, enables an easier replacement of the gripping block 1 when it needs to be replaced, and reduces the risk of the gripping block 1 jamming in the slot 4 of the holding device 2.

The embodiment described herein shall be deemed to be non-limiting. It is obvious that a skilled person may make modifications or alterations to the invention without departing from the invention as defined in the appended claims.

Claims

1. Gripping block (1) håving a rear side (6), a front side (11) and two opposing side faces (9, 10), the rear side (6) being adapted for abutment against an inner wall (5) in a slot (4) in a holding device (2), the front side (11) being arranged with friction generating means (15) over at least part of its outer surface, wherein a largest width of the rear side (6) is shorter than a smallest width of the front side (11) of the gripping block (1).

2. Gripping block (1) according to claim 1, further comprising a lower flange (12) and an upper flange (13) extending in opposite directions from the rear side (6).

3. Gripping block (1) according to claim 1 or claim 2, wherein the friction generating means (15) is arranged convex relative to the rear side (6).

4. Gripping block (1) according to any of the preceding claims, wherein an angle (Øi) between each of the two opposing side faces (9, 10) and the rear side (6) is obtuse.

5. A holding device (2) for a gripping block (1) according to any of the preceding claims, comprising: a slot (4) håving an inner wall (5) arranged for abutment against the rear side (6) of the gripping block (1); two opposing side surfaces (7, 8) arranged on each side of the inner wall (5), said side surfaces (7, 8) being shaped complementary to the opposing side faces (9, 10) of the gripping block (1) and forming an obtuse angle relative to the inner wall (5); a recess (20) adapted for receiving a lower flange (12) of the gripping block (1); and a locking member (19) for locking against an upper flange (13) of the gripping block (1).

6. A holding device (2) according to claim 5, further configured to receive fasteners (17, 18) for attachment of the locking member (19).

7. A holding device (2) according to claim 5 or 6, wherein the locking member (19) locks the upper flange (13) in abutment with the inner wall (5).

8. Method for the replacement of a gripping block (1) according to any of claims 1-4 from a holding device (2) according to any of claims 5-7, comprising the steps of: loosening the fasteners (17, 18) to access the gripping block (1); removing the gripping block (1) from the slot (4); inserting a new gripping block (1) into the slot (4) and the recess (20); and mounting the locking member (19) with the fasteners (17, 18).