Field of the invention

The invention relates to a barrier device for assembly onto a bolt, for example a rock bolt, as stated in the preamble of claim 1. The invention also relates to a method of assembling the barrier device, as stated in the preamble of claim 4, and an associated method of installing an elongate mooring element, as stated in the preamble of claim 6.

Background of the invention

Structures that are designed for floating in water must often be moored to the seabed, particularly if they are to remain at the same location for an extended period of time. Examples of such floating structures are barges, pontoon bridges, pontoons, floating breeding facilities (e.g. cages) and permanently anchored vessels. The mooring, which may comprise one or more lines, chains, wires or the like are preferably attached to respective anchors on the seabed, and the anchors may be movable (e.g. conventional anchors or suction anchors in a loose seabed) or fixedly installed in the seabed. The latter category, at which this invention is aimed, includes anchoring bolts that are installed (attached) to a solid material below the water surface. The material may be e.g. solid rock, and the anchoring bolt may be attached (installed) e.g. in a pre-drilled hole by being cast, glued/plastered and/or wedged into the borehole. Installation of bolts and other equipment may be performed by divers and/or a remotely controlled underwater vehicle («Remotely Operated Vehicle», ROV). Such fixed anchors on the seabed are also used for anchoring of subsea pipes and lines (for water, oil, gas etc.) and cables.

The prior art includes FR 517809 A, which describes a first anchor bolt which is driven into the ground. The bolt comprises an eye at its upper end portion. A wire is attached to this bolt, before a second bolt, having an enlarged head portion, extended through the eye of the first bolt, and into the ground.

The prior art also includes US 2005/044905 Al, which describes a device and method for locking an object to a tree. The device includes an eyebolt. The eyebolt is set into the tree proximate the object to be protected. A protective bracket is placed over both the eyebolt and the object. A hole is disposed in the protective bracket that aligns with the head of the eyebolt when the protective bracket is placed over the eyebolt. A lock is provided having an elongated body that extends into the hole in the protective bracket and into the eye of the eyebolt. The lock therefore interconnects the protective bracket to the eyebolt and prevents the protective bracket from being removed.

The prior art also includes US 2 569 528 A, which describes a screw anchor adapter, wherein a locking bolt may be inserted through an eye of an anchor bolt and being secured by a pin.

It is also known to use a modified, conventional, T-bolt. The end of the T-steel is chopped off, so that an end loop or shackle with an associated chain can be stringed over the T-bolt after it has been installed in the borehole. This method is widely discussed in the industry, among other things because the gradient of the mooring line is limited, as this system cannot substantially withstand vertical forces.

The prior art also includes Norwegian patent No. 342296 Bl, which describes a method of installing an anchoring bolt in a borehole under water. The stem of a T-bolt is guided through a loop of mooring chain, and a stop plate is arranged on the bolt stem below the loop to prevent the loop from falling off the stem when the anchoring bolt and the mooring chain are guided down to the seabed.

The prior art also includes Norwegian patent No. 330317 Bl, which describes an anchoring bolt where a mooring line is attached to the bolt stem by means of a fastening eye that is stringed onto the stem.

The systems in the two publications mentioned above have the common feature that the mooring line or chain is attached to the anchoring bolt on the surface and is subsequently lowered to the seabed, and that the mooring line or chain is attached to the anchoring bolt while it is being installed in the borehole. One disadvantage of this configuration and installation method is that the anchoring bolt may be loaded (e.g. by the weight of the mooring chain) and therefore move in the borehole before the casting or plastering mass has cured sufficiently. This may cause the anchoring bolt to being pulled completely or partially out of the borehole.

There is therefore a need for an anchoring device that is more reliable and easier to install, and which facilitates a suitable installation procedure. Summary of the invention

The invention is disclosed and characterized in the independent claim, while the dependent claims describe other characteristics of the invention.

Thus, a barrier device is provided for assembly onto a bolt, wherein the bolt comprises a stem and is provided with an eye at an end portion of the stem, characterized in that the barrier device comprises:

- a bolt-engaging member having barrier portion configured for abutment against at least a portion of the stem, and a receiving portion configured for abutment against the end portion; and

- a securing member, at least a part of which is adapted to be guided through the eye and comprising an engagement device configured for interaction with the receiving portion such that a movement of the securing member causes the barrier portion to be moved into abutment with the stem.

In one embodiment, the barrier portion comprises an opening, which is larger than the diameter of the stem, but at least in one orientation is smaller than the largest dimension of the head.

In one embodiment, the securing member is thread-connected with the bolt-engaging member, so that a rotation of the securing member causes a movement of the bolt- engaging member in a direction towards the bolt stem, when the barrier device is positioned on the bolt.

It is also provided a method of assembling the barrier device according to the invention, onto a bolt which comprises a stem and is provided with an eye at an end portion of the stem, characterized by: i) placing the bolt-engaging member on the bolt such that the stem extends through the barrier portion; ii) extending a forward portion of the securing member though the eye and bringing the engagement device into engagement with the receiving portion; and iii) moving the securing member until the barrier portion has been brought into abutment with the stem. In one embodiment of the method, the securing member is rotated in step iii), and the engagement device is a threaded connection.

It is also provided a method of installation of an elongate mooring element to an anchoring element on a seabed, characterized by the following steps: a) assembling the anchoring element on the seabed; b) lowering a coupling element and at least one portion of the mooring element down to the anchoring element and guiding the coupling element down onto a stem on the anchoring element; c) assembling the barrier device according to the invention onto an end portion of the anchoring element.

In an embodiment, the method comprises that before step b), a line is guided from the anchoring element to the water surface, and the line is guided into the coupling element. In an embodiment, a plurality of anchoring elements are mounted onto the seabed (step a)), before steps b) and c) are performed for each anchoring element.

The mooring element may be a chain, line, hawser or wire, and the anchoring element can be a rock bolt with an eye. The mooring element can be used for e.g. mooring of floating structures or for anchoring of subsea tubes, lines or cables.

Short description of drawings

The aforementioned and other characteristics of the invention will be further explained in the following description of embodiments of the invention, presented as non-limiting examples and with reference to the accompanying drawings, wherein:

Figure 1 is a perspective drawing, showing a first embodiment of the barrier device according to the invention in a preparatory phase, before assembly;

Figure 2 is a perspective drawing, showing the barrier device shown in figure 1 in an unassembled state;

Figure 3 is a perspective drawing of the embodiment shown in figures 1 and 2, showing the barrier device in a partially assembled state on a bolt; Figure 4 is a perspective drawing of the embodiment shown in figures 1-3, showing the barrier device in an assembled state on a bolt;

Figure 5 is a perspective drawing, showing a second embodiment of the barrier device according to the invention in an unassembled state;

Figure 6 is a perspective drawing of the embodiment shown in figure 5, showing the barrier device in an assembled state on a bolt;

Figure 7 is a perspective drawing of the embodiment shown in figures 5 and 6, showing the barrier device in a partially assembled state on a bolt;

Figure 8 is a perspective drawing, showing a third embodiment of the barrier device according to the invention in a preparatory phase, before assembly on a bolt;

Figure 9 shows the barrier device shown in figure 8 in an assembled state on a bolt;

Figure 10 is a perspective drawing, showing a fourth embodiment of the barrier device according to the invention in a preparatory phase, before assembly on a bolt;

Figure 11 shows the barrier device shown in figure 10 in an assembled state on a bolt; and

Figure 12 is a perspective drawing of a variant of the embodiment illustrated by figures 1-4.

Detailed description of embodiments of the invention

The following description will use expressions such as "horizontal", "vertical'', "lateral", "back and forth", "up and down", "upper", "lower", “inner", “outer", "forward", "rear", etc. These expressions essentially refer to the perspectives and arrangements shown in the drawings and related to a normal use of the invention. The expressions are used only to facilitate the comprehension of the description and shall not be limiting.

A first embodiment of the invention will now be described with reference to figures 1-4 and 12. Figure 1 shows a bolt 10 of an essentially known type. The bolt may be a conventional eye bolt normally used for anchoring, and may be installed (attached) to a solid material below a water surface. This material (not shown) may be e.g. solid rock, and the anchoring bolt 10 may be attached in a pre-drilled hole (not shown) by being cast, glued/plastered and/or wedged into the borehole. Other attachment methods are conceivable though they are not described here. The bolt 10 in the illustrated embodiment has a stem 11, the length of which is dimensioned according to the relevant requirement, a first (upper) end portion provided with a head 12 and a second (lower) portion 14. The lower portion or part of it is guided into the pre-drilled hole mentioned above. It shall be understood that the length of the bolt may be longer or shorter than shown in the figures. The head 12 is provided with a through-going bore, in the following referred to as an eye, 13.

Figure 1 shows a mooring chain 20 attached to the stem 11. The mooring chain comprises several loops 21 and an end loop 22. Here, the end loop 22 is guided over the upper end portion (head) 12 of the bolt after the bolt has been installed in the pre-drilled hole, for example by a method described below. It shall be understood that the invention is not limited to anchoring of such chains, but will also comprise lines, wires or the like, attached to the stem by means of a loop, shackle or the like, which can be used for e.g. mooring of floating structures or for anchoring of subsea tubes, lines or cables.

In the embodiment illustrated in figures 1-4 and 12, the invented barrier device 30 comprises a bolt-engaging member 31 and a securing member 32.

The bolt-engaging member 31 comprises a barrier portion 31a having an opening 37, which is larger than the diameter of the stem 11, but smaller than the largest dimension of the head 12. An access slot 38, in the barrier portion 31a, with a corresponding dimension enables guidance of the stem 11 into the opening 37. This access slot is not a mandatory feature. That is, the opening 37 may be fully enclosed by the barrier portion provided it is shaped and dimensioned such that the bolt head may pass though the opening in one orientation but not in another. For example, the opening 37 may have a rectangular shape with one pair of parallel sides being longer than the other pair of parallel sides.

The bolt-engaging member 31 also comprises a receiving portion 35 with a through- going hole 36 provided with threads. The barrier portion 3 la is preferably (but optionally) provided with bevelled portions 37a at the opening 37 for improving the abutment of the barrier portion against the head 12.

The securing member 32 comprises an elongated member, e.g. a stem, with a manipulation interface (here: a handle) 39 at one end, a threaded portion 34 and a forward portion 33. The threaded portion 34 of the securing member 32 is configured for engagement with the threads in the hole 36 in the receiving portion 35.

An assembly procedure will now be described with reference to figures 3 and 4. In figure 3, the bolt-engaging member 31 is arranged on the stem 11 via the access slot 38, so that the opening 37 encompasses the stem 11. The forward portion 33 is guided through the eye 13 of the bolt head 12, and the threaded portion 34 is brought into engagement with the threads in the hole 36. A rotation of the securing member 32, preferably by operating the manipulation interface (handle) 39, causes the bolt-engaging member 31 - more precisely: the in the barrier portion 3 la - to be moved towards the stem and thereby locking the barrier portion 3 la in supporting engagement with the bolt head 12. As the barrier device 30, and each of the bolt-engaging member 31 and securing member 32, is larger than the end loop 22, the barrier device 30 prevents the mooring chain 20 from coming loose from the bolt 10. Although the movement of the bolt-engaging member 31 in the illustrated embodiment is described as being caused by interaction between the above-mentioned threaded connection, it should be understood that other means and methods for causing a similar movement are conceivable. The invention shall therefore not be limited to a threaded connection.

Figure 12 illustrates a variant of the first embodiment illustrated by figures 1-4. Here, the securing member 32 comprises a manipulation interface 39’ having shape configured for connection to a suitable tool, e.g. an ROV-operated tool. This variant also comprises a locking device 7 (here: a screw, or similar) arranged on the receiving portion and which may be operated to prevent the securing member from rotating, e.g. when the barrier device has been installed.

A second embodiment of the invention will now be described with reference to figures 5-7. It should be understood that the bolt 10 and the mooring chain 20 in the following description may be of the same types, and attached, as described above. In the illustrated embodiment, the invented barrier device 40 comprises a bolt-engaging member 41 and a securing member 42, see particularly figure 5.

The bolt-engaging member 41 comprises a barrier portion 41a having a curved portion, forming an opening 47, which is larger than the diameter of the stem 11, but smaller than the largest dimension of the head 12. An access slot 48 in the curved portion enables guidance of the stem 11 into the opening 47. This access slot is not a mandatory feature. That is, the opening 47 may be fully enclosed provided it is shaped and dimensioned such that the bolt head may pass though the opening in one orientation but not in another. For example, the opening 47 may have an oval or elliptical shape.

The bolt-engaging member 41 also comprises a receiving portion 45 with a through- going hole 46 provided with threads. The rounded profile portion 47a of the bolt- engaging member 41 facilitates improved abutment of the a barrier portion 41a against the head 12.

The securing member 42 comprises an elongated member, e.g. a stem, with a manipulation interface (here: a handle) 49 at one end, a threaded portion 44 and a forward portion 43. The threaded portion 44 of the securing member 42 is configured for engagement with the threads in the hole 46 the receiving portion 45. In the illustrated embodiment, the threads are left threaded.

An assembly procedure will now be described with reference to figures 6 and 7. In figure 6, the bolt-engaging member 41 is arranged on the stem 11 via the access slot 48, so that the opening 47 encompasses the stem 11. The forward portion 43 is guided through the eye 13 of the bolt head 12, and the threaded portion 44 is brought into engagement with the threads in the hole 46. A rotation of the securing member 42, preferably by operating the manipulation interface (handle) 49, causes the bolt-engaging member 41 - more precisely: the in the barrier portion 41a - to be moved towards the stem and thereby locking the barrier portion 41a in supporting engagement with the bolt head 12. As the barrier device 40, and each of the bolt-engaging member 41 and securing member 42, is larger than the end loop 22, the barrier device 40 prevents the mooring chain 20 from coming loose from the bolt 10. Although the movement of the bolt-engaging member 41 in the illustrated embodiment is described as being caused by interaction between the above-mentioned threaded connection, it should be understood that other means and methods for causing a similar movement are conceivable. The invention shall therefore not be limited to a threaded connection. This embodiment may also comprise a securing member tool interface and locking device similar to the ones described above with reference to figure 12.

A third embodiment of the invention will now be described with reference to figures 8 and 9. It should be understood that the bolt 10 in the following description may be of the same types, and attached, as described above. Even though the mooring chain (line, wire etc.) 20 is not shown in figures 8 and 9, it should be understood that it can be attached to the stem 11 in the same manner as described above.

In this embodiment, a barrier device 50 comprises a single elongate element. Figures 8 and 9 show the barrier device 50 as a barrier bolt with a round stem, but it should be understood that the barrier device can have other stem cross-section shapes. The barrier device 50 has a first (forward) portion 53 with a cross-section dimension (here: diameter) that is smaller than the opening of the eye 13, and a second (rear) portion 52 with a cross-section dimension (here: diameter) that is larger than the opening of the eye 13. A shoulder 55 marks the transition between the two portions. A head 51, which can be operated by an operator, an ROV or the like, is arranged at the end of said rear portion.

During assembly, the barrier device 50 is guided into the eye 13, until the shoulder abuts the head 12. As the barrier device 50 is larger than the end loop 22 (not shown in figures 8 and 9), the barrier device 50 prevents the mooring chain 20 from coming loose from the bolt 10. The barrier device 50 is attached in the eye 13 in a suitable manner. In one embodiment, the eye 13 can be provided with threads 15, and part of the first (forward) portion 53 can be provided with threads 54, so that the barrier device 50 can be screwed into the eye 13. A locking wire (not shown) can then be guided through a hole 57 of the barrier device 60. The first (forward) portion 53 can alternatively be provided with other attachment means, such as glue, wedges or the like, for attachment in the eye 13. This embodiment of the barrier device does not require a specific size of the anchoring bolt head, because the barrier device 50 does not have a bolt-engaging member (cf. reference numerals 31 and 41 described above) against which the bolt head must abut.

A fourth embodiment of the invention will now be described with reference to figures 10 and 11. It should be understood that the bolt 10 in the following description may be of the same types, and attached, as described above. Even though the mooring chain (line, wire etc.) 20 is not shown in figures 10 and 11, it should be understood that it can be attached to the stem 11 in the same manner as described above.

In this embodiment, a barrier device 60 comprises a single elongate element. Figs 10 and 11 show the barrier device 60 as a barrier bolt with a round stem, but it should be understood that the barrier device can have other stem cross-section shapes. The barrier device 60 has a first (forward) portion 63 with a cross-section dimension (here: diameter) that is smaller than the opening of the eye 13, and a second (rear) portion 62 with a cross-section dimension (here: diameter) that is larger than the opening of the eye 13. A shoulder 65 marks the transition between the two portions. A head 61, which can be operated by an operator, an ROV or the like, is arranged at the end of said rear portion.

During assembly, the barrier device 60 is guided into the eye 13, until the shoulder abuts the head 12. As the barrier device 60 is larger than the end loop 22 (not shown in Figs 10 and 11), the barrier device 60 prevents the mooring chain 20 from coming loose from the bolt 10. The barrier device 60 is attached in the eye 13 in a suitable manner. In the illustrated embodiment, part of the first (forward) portion 63 may be provided with threads 64 that are adapted to the treads on a locking nut 66. This embodiment of the barrier device does not require a specific size of the anchoring bolt head, because the barrier device 60 does not have a bolt-engaging member (cf. reference numerals 31 and 41 described above) against which the bolt head must abut. During assembly, the barrier device 60 is guided through the eye 13, until the shoulder 65 hits the bolt head. Then the nut 66 is screwed onto the threaded portion 64, so that the barrier device 60 is attached to the bolt as shown in Figure 11. A locking wire (not shown) may then be guided through the hole 67 of the barrier device 60. A common feature for all embodiments described above is that the barrier devices 30; 40; 50; 60 are configured for assembly on a standard eye bolt, such as e.g. the anchoring bolt 10, and that the barrier devices are larger than the end loop 22 of the mooring chain, so that the barrier devices prevent the mooring chain 20 from coming loose from the anchoring bolt 10.

The arrangement according to the invention also enables a substantially more efficient installation of subsea anchoring bolts than allowed by prior art, and is particularly suitable when a large number of bolts are to be installed. This is illustrated by the following description of a method of installation of one or more anchoring bolts on a seabed:

- The desired number of holes are drilled in the seabed.

- Eye bolts are installed in the individual boreholes and are attached in the borehole in a known manner. If desired, each eye bolt can be provided with a line (not shown) for the surface and be coupled to a buoy, so that the line can be picked up by an installation vessel on the surface.

- When the eye bolts are attached to the borehole (cast, cured, etc.), a mooring chain 20 can be installed on each bolt 10, e.g. by an end loop 22 or the like being stringed onto the line and transferred from the surface and down to the respective bolt stem 11.

- The line can subsequently be cut, and a barrier device 30; 40; 50 can be mounted as described above.

The mooring chains 20 can obviously also be installed without the use of such lines and buoys.

All operations on the seabed, including installation of the barrier devices 30; 40; 50 according to the invention can be performed by divers and/or ROVs.

Through the invention is described with reference to subsea installation, it should be understood that the arrangement according to the invention can also be used on land.