WO2014112883A1

WO2014112883A1 - Coupling system for coupling an rov to a tms

Info

Publication number: WO2014112883A1
Application number: PCT/NO2014/050007
Authority: WO
Inventors: Ilan Sharoni
Original assignee: INNOVA AS
Current assignee: INNOVA AS
Priority date: 2013-01-17
Filing date: 2014-01-15
Publication date: 2014-07-24
Anticipated expiration: 2015-07-17
Also published as: NO336789B1; NO20131645A1

Abstract

The invention relates to a coupling system for coupling an underwater remotely operated vehicle or a load (13) to a tether management system (1) from below, in operational use, wherein the coupling system comprises a locking mechanism and a cable termination (2) for a tether (20), wherein the locking mechanism is coupled between the tether management system (1) and the vehicle or load (13), wherein the cable termination (2) is configured for being received and locked into the locking mechanism, and wherein the locking mechanism is configured for receiving and forming a two-dimensional enclosure (11) for the cable termination (2), and being further configured such that a size of said enclosure (11) is gradually reduced as the cable termination (2) is moving into the enclosure (11).

Description

COUPLING SYSTEM FOR COUPLING AN ROV TO A TMS

The invention relates to a coupling system for coupling an underwater remotely operated vehicle (ROV) or a load to a tether management system (TMS) from below.

An ROV is an unmanned vehicle which is used for various underwater operations. As an ROV has an approximately neutral weight in the water, it is a challenge to lower the ROV to the position where the work/operations are being performed, possibly within a depth of several kilometres. To speed up the vertical transportation, a TMS which is a "kind of" ROV elevator is being used. The TMS is heavier than water and is thus easily sinking. The TMS is connected to the surface through a cable called umbilical cord, which is both carrying the weight as well as transporting electricity and communication. The umbilical cord is being winded up on a drum (or reel) which is located on a boat or platform. A handling system, typically an A-frame, is lifting the TMS off from the deck and over board.

Another reel is placed within the TMS with a cable (tether) which is transmitting electricity and communication between the TMS and the ROV. The TMS is obtainable in two main variations; one where the ROV is parked within the TMS and one where the ROV or a corresponding load is connected under the TMS. The invention is related to this second variant. There is a coupling mechanism to lock/connect the end of the tether to the underside of the TMS where the ROV is hanging under the TMS. This end of the tether is fastened to the top of the ROV and is terminated by a steel device which is connecting the TMS and the ROV together without putting load on the tether. In case of a TMS, where the ROV is hanging below, the tether is running through a trumpet shaped opening in the bottom of the TMS. A locking system (latching) is placed right above the opening and is catching the termination of the tether when the tether is pulled in. The coupling of TMS and ROV under water is presupposing that the TMS drum is winding the tether, as the ROV cannot push the tether into the TMS through the opening. Hence the tether needs to be winded in faster than the speed of which the ROV and TMS is approaching each other. As mentioned above the TMS is "hanged" from the surface. This means that it is moving up and down in pace with the waves even if it is situated several kilometres below the surface. This movement of the TMS does not occur when the TMS is being hanged from a platform. When the TMS is hanging from a ship, the movement can be cancelled if the ship is actively compensating the wave movement by winding/unwinding the drum. In some cases one shall have to connect the ROV and TMS when the TMS is moving. If the ROV and TMS are approaching faster than the tether is being pulled in, the tether might be damaged and in worst case it can be cut off as the cable termination is entering the opening of the TMS before the tether is completely pulled in, or if the cable termination is hitting the underside of the TMS.

WO02/06146A1 discloses a tether management system including a drum of tether, which includes a pivoted fairlead which pivots about a tether exit hole arranged below the drum. The system guides tether vertically into the exit hole.

US6,276,625B1 discloses a method of ROV tether storage without the use of electrical rotary slip rings, and a tether storage drum. The heart of this Tether Storage System (TSS) involves the rotating beam with a powered tether sheave and guide plate on a circular track. The concept of a rotating beam with a powered tether sheave and beam drive motors in a single unit is different than earlier tether storage and handling systems. It discloses rotation of the sheave about the TSS frame's vertical axis. To accomplish this, preferably a drive motor is mounted at each end of the bea m. A drive wheel on each motor reacts against the channel track to rotate the beam. Rollers at each end of the beam support and guide it. The tether is stored in a large circular basket below the sheave in the cylindrical frame. A guide plate attached to the sheave beam rests on top of the tether in the storage basket. This plate rotates with the beam and moves vertically to remain on top of the tether, to facilitate feeding on deployment and storage. The tether passes from the basket through the guide plate feed gap, to the tether sheave, then through the guide tube and docking assembly, from the TSS to the ROV. The tether path is simple and direct with a minimum of bending, tensioning, and twisting. The overall configuration is a cylindrical pipe frame that houses the rotating sheave beam unit, tether guide plate, storage basket, and other operating components. This system captures and deploys the ROV for launch and recovery from the surface to the working depth. A docking pin on top of the ROV mates with the TSS docking assembly to provide this control. The TSS extends the operational parameters for ROV submersibles by freeing it from surface effects, in column currents, and main umbilical drag.

Thus, one of the problems of the known systems is that when the ROV is returning to the TMS the tether might get strangled if it is not being winded fast enough. Further- more, docking of the ROV may be cumbersome.

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.

In a first aspect the invention relates more particularly to a coupling system for coupling an underwater remotely operated vehicle or a load to a tether management system from below, in operational use, wherein the coupling system comprises a locking mechanism and a cable termination for a tether, wherein the locking mechanism is coupled between the tether management system and the vehicle or load, wherein the cable termination is configured for being received and locked into the locking mechanism, and wherein the locking mechanism is configured for receiving and forming a two-dimensional enclosure for the cable termination, and being further configured such that a size of said enclosure is gradually reduced as the cable termination is moving into the enclosure. Thus an important aspect of the invention is that the coupling system comprises of two parts, namely a locking mechanism and a cable termination that is received in the locking mechanism, and that the enclosure formed by the locking mechanism gradually reduces as the cable termination is moved further into the locking mechanism. In one variant the cable termination can be implemented on the top of the ROV, while the locking mechanism is mounted on the bottom of the TMS. However, this may also be inversed, in that the locking mechanism is provided on the top of the ROV, and the cable termination on the bottom of the TMS. Even though the first variant has a clear advantage over the second, as will be obviated in the discussion of some of the embodiments, both variants are considered to fall within the scope of the invention as claimed.

The feature "cable termination" is to be interpreted as a protruding element for carrying a tether entering from a hole in a top end thereof and for guiding said tether further to the vehicle/load or TMS. Effectively it may form part of the cable and be permanently connected to it, but it may also connected to a top part of an underwater remotely operated vehicle or load, in operational use.

The wording "two-dimensional enclosure for the cable termination" is to be interpreted as an opening for inserting the cable termination, wherein the opening in projection in the direction of the cable termination on a virtual plane cutting said cable termination, encloses the cable termination. In an embodiment of the coupling system the locking mechanism has been fixed to a bottom part of the tether management system, and the cable termination has been fixed to a top part of the vehicle or load . This embodiment constitutes the earlier discussed first main variant of the invention. First of all, this embodiment is advantageous, because the ROV can be kept lighter and smaller, as it does not require the locking mechanism to be provided on its top. Further, advantages will be explained in view of the different embodiments of this variant.

In an embodiment of the coupling system said locking mechanism comprises two pairs of oppositely placed gates, each pair defining a slot, wherein the pairs of gates are preferably perpendicularly mounted so that the slots between said pairs of gates together form the enclosure when projected in a direction of said cable termination, wherein the enclosure is square-shapped, rectangular-shaped or parallelogram- shaped. Using two pairs of oppositely placed gates, each pair forming a respectively slot, constitutes a convenient way of making a two-dimensional enclosure that is gradually reduced in size for locking. Preferably, such pairs of gates are placed substantially orthogonal, but this is not essential. Orthogonally placed gates makes the design of the locking mechanism a bit easier.

In an embodiment of the coupling system said gates are mounted in a pivoting manner in said locking mechanism, such that a pivoting simultaneous motion of all gates together either increases or decreases a size of said enclosure depending on a direction of said pivoting movement. The advantage of using pivoting gates is that it enables to make the design such that pressing against the gates to make them move inwardly also results in a reducing of the size of the enclosure, i.e. it facilitates a very simple and convenient mechanism.

In an embodiment of the coupling system an inward movement of said gates decreases the size of said enclosure, wherein, in operational use, either the top part of the vehicle or load or the bottom part of the tether management system is used to push said gates inwardly and close the locking mechanism, when it moves towards to the tether management system, and wherein an outward movement of said gates increases the size of said enclosure, wherein preferably, in operational use, after unlocking, said locking mechanism is opened and/or kept in an open position by the weight of said gates or by spring force. Depending on the main variant chosen, either the weight of the gates can be used to open (after unlocking) the locking mechanism or spring force can be used.

In an embodiment of the coupling system said gates each comprise a roller element at its edge defining said slots, and/or each comprises wheels at ends thereof for rolling on the top part of said vehicle or load. The use of roller has the advantage that the locking of the cable termination in the locking mechanism is smoothened as the gates can roll of the surface of the cable termination. A further advantage is that the tether is protected when being pulled in or out.

In an embodiment of the coupling system the system further comprises locking means for keeping said gates in a locked position after receiving and locking said cable termination, and preferably comprising releasing means for releasing said gates for decoupling the underwater remotely operated vehicle or a load from the tether management system. It is convenient to keep the locking mechanism locked until the moment that the ROV is to be released again. Various techniques are available to achieve this effect, of which one has been described in the following detailed description.

In a second aspect the invention relates more particularly to the locking mechanism for use in the coupling system of the invention. As a matter of fact both locking mechanism as well as the cable termination have been adapted in order to achieve the locking effect of the invention and both are characterized over the prior art. Both parts act together as a plug and socket. Therefore, the inventor is entitled to a claim directed to the locking mechanism as well as to entities comprising such locking mechanism.

In a third aspect the invention relates more particularly to a tether management system comprising the locking mechanism of the invention.

In a fourth aspect the invention relates more particularly to cable termination for use in the coupling system of the invention. As a matter of fact both locking mechanism as well as the cable termination have been adapted in order to achieve the locking effect of the invention and both are characterized over the prior art. Both parts act together like a plug and a socket. Therefore, the inventor is entitled to claims directed to the cable termination as well as to entities comprising such cable termination.

In a fifth aspect the invention relates more particularly to an underwater remotely operated vehicle or load being provided with the cable termination of the invention, wherein the cable termination is provided on a top part of the remotely operated veh icle or load.

In the following is described an example of a preferred embodiment illustrated in the accompanying drawings, wherein : Fig. 1 shows a front-view of an embodiment of the locking mechanism of the invention when in an open position;

Fig. 2 shows a side-view of the embodiment of Fig. 1 ;

Fig. 3 shows a bottom-view of the embodiment of Fig. 1;

Fig. 4 shows a front-view of an embodiment of the locking mechanism of the invention when in a closed position;

Fig. 5 shows a side-view of the embodiment of Fig. 4;

Fig. 6 shows a bottom-view of the embodiment of Fig. 4

Fig. 7 shows in a larger scale the coupling system of the invention part of the locking mechanism as well as the cable termination;

Fig. 8 shows in a larger scale a gate in accordance with an embodiment of the invention;

Fig. 9 shows a further gate in accordance with an embodiment of the invention;

Fig. 10 shows part of the locking mechanism when in an open position;

Fig. 11 shows the part of Fig. 10 when in a closed position, and

Fig. 12 shows in a smaller scale a complete TMS and ROV system in operational use.

The invention will be discussed in more detail hereinafter, in particular in relation to an advantageous embodiment. It must be noted however, that other embodiments are also possible and do not depart from the scope of the invention as claimed . In order to support this statement some of the possible variations and alternatives will be discussed after the discussion of the advantageous embodiment.

Fig. 12 shows a complete TMS and ROV system in operational use. The figure shows a TMS (1) which is coupled to a boat or ship (99) via an umbilical cord (25). The TMS is coupled to an ROV (15) via a tether (20). The figure further illustrates that the ROV (15) is attached to a cable termination (2) on its top side and the TMS (1) is provided with a locking mechanism (30) at its bottom side for receiving the cable termination (2).

The TMS coupling system (more precisely the locking mechanism (30) of the coupling system, which remark is also valid for the remaining discussion of the figures) is illustrated in the drawings, where Figs. 1 to 3 are showing a TMS (1) with a coupling system in open position and Figs. 4 to 6 are showing the system in a closed position. Figs. 1 and 4 are showing the front, Figs. 2 and 5 are showing the side and Figs. 3 and 6 are showing the bottom. Fig. 7 is showing a cable termination on the top of a load (13) caught between the rollers of the coupling system (3a, 4a).

An H-construction (3b, 4b) constitutes the frame for each gate (3, 4) shown in Figs. 8 and 9. One of the ends of the gates is hinged (5) under the TMS (1). In the other end the frame (3b, 4b) rollers (3a, 4a) which are mounted on the ends (3b, 4b) of the frames via bearings (3c, 4c). (12) are wheels made of soft material. The stoppers (3d and 4d, shown in Figs. 1, 2, 10 and 11) are securing the gates to prevent them from tilting upwards. The buffer (3e, 4e) is a "soft" pipe with a D-profile to protect the top of the load when the TMS and the ROV are connected. The fastener (7) which is shown in Figs. 10 and 11, is hinged from the frame (4b) and closed against the pins (8) in the bottom of the TMS (la). The fastener (7) has at least two positions, one for closed gate shown in Fig. 11, and one for open gate shown in Fig. 10. A third position could be identified as the closed, but freely movable position. A spring (9) is pushing the fastener against the pin (8) so that it can be easily moved from position a (PA) to position b (PB) along a track 7b. However, it is locked in position b (PB). A cylinder (10) pulls the fastener (7) to bring the pin (8) from position b (PB) into the track (7b) to release the fastener (7) . A piston rod (10a) extends through the spring (9) and is coupled to a hole (7a) in the fastener (7) enabling only pulling not pushing the fastener (7). At the same time the piston rod keeps the spring (9) in a correct position.

The gates (3, 4) are placed under the TMS (1) in two pairs that are shown perpendicularly positioned. This is shown in Figs. 3 and 6. From the front view of Fig. 4 and the side view of Fig. 5 one can see that the pairs of gates (3, 4) are positioned on top of each other, with a height difference between the hinges (5) which is equal to the d iameter of the rollers. Both pairs of gates (3, 4) are horizontally hanging when the gates (3, 4) are closed. This is important to achieve an underside which is even and coherent.

The pairs of gates (3, 4) are not completely equal. The pair of gates (4) in the top position are a little narrower, otherwise the side beams (4f) would have collided with the side beams (3f) of the pair of gates (3) in the lower position. Furthermore a locking mechanism (7-10) is only needed at one of the gates (3) to lock the system. It is an advantage, however, that both the underlying gates (3) can be locked in position. The upper gates (4) are caught between the stopper (3d) in the lower gates (3) and the bottom of the TMS (la). The load which the cable termination (2) puts on the rollers (3a and 4a) is thereby more evenly distributed, and for the transportation on shore it can be desired to secure all the gates (3, 4) in closed position.

Fig. 7 shows the cable termination (2) which is equipped with 1 or 2 circular rims (2a) that has a bigger outer diameter than the width of the funnel (11) which is created between the rollers (3a and 4a) when the gates (3, 4) are closed (Fig. 6). Even if the use of one circular rim (2a) can be sufficient - the use of 2 circular rims (2a) will better distribute the load and wear. Fig. 7 further shows part of a tether (20) which enters the cable termination (2) through an opening on a top end thereof.

So in summary the embodiment of the coupling system as illustrated in Figs. 1 to 12 comprises two pairs of gates (3, 4) that are hinged under the TMS (1) and a cable termination (2) with a profile to fit the enclosure (11) which is formed between the gates (3, 4) when all the gates are closed. The gates (3, 4) are kept in position both in open and closed position by a fastener (7) that is hinged on each of the ledger beams (3f) to the lower gates (3). A piston rod (10a) is going through a hole in the fastener (7a) from a cylinder (10b) which is hinged on the same ledger beam (3f, 4f). A spring (9) is placed around the piston rod (10a) between the cylinder housing (10b) and the fastener (7) and is pushing the fastener against a pin (8) in the constructions of the TMS. A wheel of soft material (12) is mounted in each corner of the gates (3, 4). The edges of the respective gates (3, 4) which create the respective slot (11a, l ib) each comprise a roller (4a, 3a).

The invention also relates to a coupling system as defined in the following clauses:

1. Coupling system for TMS where a ROV or a corresponding load to be attached from below to a TMS by use of a locking mechanism of a cable termination in the end of a cable, which is supplying the load with electricity and communication, characterized by 2 pairs of gates (3, 4) perpendicularly mounted under the TMS (1) so that the slots (11a and l ib) between all the gates (3, 4) make a square-shaped clamp (11).

2. Coupling system for TMS in accordance with clause 1, characterized by the gates (3, 4) are being locked in closed position by use of spring-loaded hooks (7) which only need power supply to open the gates (3, 4), not to close them. 3. Coupling system for TMS in accordance with clauses 1-2, characterized by the gates (3, 4) are being pushed in and closed by the top of the load (13a) when the ROV or a corresponding load (13) and the TMS (1) are being pushed against each other.

4. Coupling system for TMS in accordance with clauses 1-3, characterized by the gates (3, 4) are being opened and kept in an open position by use of their own weight when the hooks (7) are being loosened and the TMS (1) and load (13) are separated from each other.

5. Coupling system for TMS in accordance with clauses 1-4, characterized by the edges of the gates are consisting of rollers (3a, 4a) and creating the slots (11a, l ib).

6. Coupling system for TMS in accordance with clauses 1-5 characterized by the corners of the gates (12) are consisting of wheels made by a soft material.

As can be extracted from the discussion of the preferred embodiment with respect to the drawings, the main gist of the invention resides in the provision of coupling system for coupling an underwater remotely operated vehicle or a load (13) to a tether management system (1) from below, in operational use. Further that the coupling system comprises a locking mechanism and a cable termination (2) for a tether (20), wherein the locking mechanism is coupled between the tether management system (1) and the vehicle or load (13), wherein the cable termination (2) is configured for being received and locked into the locking mechanism. And further that the locking mechanism is configured for receiving and forming a two-dimensional enclosure (11) for the cable termination (2), and being further configured such that a size of said enclosure (11) is gradually reduced as the cable termination (2) is moving into the enclosure (11).

It must be stressed that the use of (pivoting) gates constitutes one way of achieving this effect, but other ways exist as well, such as the use of a diaphragm construction wherein the size of the diaphragm is gradually reduced as the cable termination moves into the hole of the diaphragm. Further mechanical means may be provided to ensure that the diaphragm gradually reduces its opening when the cable termination moves into this hole. For instance a spring loaded protruding pressable element which is pressed in when a top of the ROV or the bottom of the TMS is very near.

It must also be stressed that kinematic reversals may be considered as well, i.e. that the locking mechanism is provided on the ROV and the cable termination is provided on a bottom of the TMS. It should be noted that the above-mentioned embodiments illustrate rather than limit 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 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 elements 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. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Throughout the Figures, similar or corresponding features are indicated by same reference numerals or labels.

Claims

C l a i ms

A coupling system for coupling an underwater remotely operated vehicle or a load (13) to a tether management system (1) from below, in operational use, wherein the coupling system comprises a locking mechanism (30) and a cable termination (2) for a tether (20), wherein the locking mechanism (30) is coupled between the tether management system (1) and the vehicle or load (13), wherein the cable termination (2) is configured for being received and locked into the locking mechanism (30), and wherein the locking mechanism (30) is configured for receiving and forming a two-dimensional enclosure (11) for the cable termination (2), and being further configured such that a size of said enclosure (11) is gradually reduced as the cable termination (2) is moving into the enclosure (11).

The coupling system as claimed in claim 1, c h a r a c t e r i s e d i n that the locking mechanism (30) has been fixed to a bottom part of the tether management system (1), and wherein the cable termination (2) has been fixed to a top part (13a) of the vehicle or load (13).

The coupling system as claimed in claim 1 or 2, c h a r a c t e r i s e d i n that said locking mechanism (30) comprises two pairs of oppositely placed gates (3,4), each pair defining a slot (11a, lib), wherein the pairs of gates (3, 4) are preferably perpendicularly mounted so that the slots (11a, lib) between said pairs of gates (3,4) together form the enclosure (11) when projected in a direction of said cable termination (2), wherein the enclosure (11) is square-shaped, rectangular-shaped or parallelogram-shaped.

The coupling system as claimed in claim 3, c h a r a c t e r i s e d i n that said gates (3, 4) are mounted in a pivoting manner in said locking mechanism, such that a pivoting simultaneous motion of all gates (3, 4) together either increases or decreases a size of said enclosure (11) depending on a direction of said pivoting movement.

The coupling system as claimed in claim 3 or 4, c h a r a c t e r i s e d i n that an inward movement of said gates (3, 4) decreases the size of said enclosure (11), wherein, in operational use, either the top part (13a) of the vehicle or load (13) or the bottom part (la) of the tether management system (1) is used to push said gates inwardly and close the locking mechanism (30), when it moves towards to the tether management system (1), and wherein an outward movement of said gates (3, 4) increases the size of said enclosure (11), wherein preferably, in operational use, after unlocking, said locking mechanism (30) is opened and/or kept in an open position by the weight of said gates (3, 4) or by spring force.

6. The coupling system as claimed in any one of claims 3 to 5, c h a r a c t e r i s e d i n that said gates (3, 4) each comprise a roller element (3a, 4a) at its edge defining said slots, and/or each comprises wheels (12) at ends thereof for rolling on the top part (13a) of said vehicle or load (13).

7. The coupling system as claimed in any one of claims 3 to 6, c h a r a c t e r i s e d i n that the system further comprises locking means (7, 7a, 7b, 8, 9) for keeping said gates (3, 4) in a locked position after receiving and locking said cable termination (2), and preferably comprising releasing means (10, 10a, 10b) for releasing said gates (3, 4) for decoupling the underwater remotely operated vehicle or a load (13) from the tether management system (1).

8. The locking mechanism (30) for use in the coupling system according to any one of the preceding claims.

9. A tether management system (1) comprising the locking mechanism (30) of claim 8.

10. The cable termination (2) for use in the coupling system according to any one of claims 1 to 7.

11. An underwater remotely operated vehicle or load (13) being provided with the cable termination (2) of claim 10 that is provided on a top part (13a) thereof.