WO2005054710A1

WO2005054710A1 - Rope terminations

Info

Publication number: WO2005054710A1
Application number: PCT/GB2004/004993
Authority: WO
Inventors: Neil Richard Schulz
Original assignee: Marlow Ropes Limited
Priority date: 2003-11-27
Filing date: 2004-11-26
Publication date: 2005-06-16
Also published as: GB0327600D0

Abstract

A rope, (2) comprises a plurality of load bearing cores (4), each core (4) being spliced to itself at its end to form a connecting eye (10). The connecting eyes (10) of respective cores (4) are arranged around designated load pins (12) which extend between load plates (14) whereby load is transmitted from the rope (2) into the plates (14) through a plurality of said load pins (12).

Description

ROPE TERMINATIONS The present invention relates to rope terminations particularly, but not exclusively, for use with marine ropes as are used, for example, in mooring vessels to the seabed. The search for offshore fossil fuels is moving into deeper and deeper waters. In shallower waters, drilling and protection vessels have traditionally be moored to the seabed using chain and wire. In deeper waters, however, there has been a move towards mooring these vessels with synthetic fibre ropes as these offer many advantages such as reduced platform offset, reduced peak loads and increased payload capacity. In view of the considerable lengths of rope which may be required, and limitations in manufacturing and handling techniques with synthetic fibre ropes, the ropes have to be split into a number of sections. Typically a mooring rope will be split into 4 or 5 sections . These sections are connected together using a steel spool arranged inside the rope's eye end termination. Adjacent steel spools are then attached to respective ends of a small length of chain using shackles. However, such an arrangement is undesirable since as the requirement for breaking loads is increased, the size and weight of the connections also increase. This not only makes them difficult to handle and connect, but it can also have an effect on the dynamics of the mooring system. The present invention therefore seeks to provide an improved connecting termination. From a first aspect, therefore, the invention provides a rope termination, said rope comprising a plurality of load bearing cores, each said core being spliced to itself at its end to form a connecting eye, said termination further comprising a connector comprising a plurality of load bearing members, the connecting eyes of respective cores being arranged around designated load bearing members whereby the load is transmitted from said rope to said connector through a plurality of said load bearing members . Thus in accordance with the invention a termination couples a plurality of load bearing cores in a rope to a plurality of load bearing members in the connector. The connector can then be connected by suitable means to a second rope or other component . Preferably the load bearing members comprise a plurality of load pins which extend between respective supports, for example load plates. One end of each load pins may be formed integrally with one of the load plates, the core eyes being positioned over the load pins and the second load plate then being secured in position over the load pins. Alternatively, the load pins may be separate from and secured to both load plates by suitable means . In one embodiment a side plate may be mounted over the load plate with fasteners extending into the load pins and the load plates . The side plate may be provided with a skid plate to protect it and the connection from the external environment . As mentioned above, the supports preferably comprise means for connecting the support to a second rope or to another component . In a first embodiment the additional connection means may comprise a bore for receiving a shackle pin or the like. Preferably, however, the additional connection means comprises a second set of load bearing members for receiving connecting eyes of the load bearing cores of a second rope. Preferably the load bearing members and supports are manufactured from a high strength material which has a high resistance to corrosion and sea water. Suitable materials may include fibre composites, titanium alloys or high strength steel alloys. Preferably the load bearing members are arranged at different spacings from the end of the rope. For example, they may be arranged in one or more rows spaced apart axially in the direction of the rope. Preferably more than one core is mounted over each load bearing member. In order to facilitate assembly of the termination, the rope end is preferably encapsulated in a suitable material to provide a unitary body which may be positioned over the load bearing members of the termination. To this end, the core eyes may be positioned over a mould core and an encapsulating material such as polyurethane filled into the mould. The encapsulating material then sets to produce a solid rope end which may more easily be manipulated and connected to the load bearing members . This is a novel arrangement in its own right, so from a further aspect the invention provides a rope termination, said rope comprising a plurality of load bearing cores, each said core being spliced to itself at its end to form a connecting eye, said core ends being encapsulated in a surrounding material to fix them in position relative to each other. From a yet further aspect, the invention provides a method of terminating a rope, said rope having a plurality of cores, each said core being spliced to itself at its end to form a connecting eye, comprising placing said core ends in a mould with said eyes positioned over one or more mould cores, introducing an encapsulating^{^}material into the mould, allowing said encapsulating material to solidify, and removing the encapsulated rope termination from the mould and the mould core(s) . Some preferred embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 shows a first embodiment of rope termination in accordance with the invention; Figure 2 is a schematic section along line II-I I of Figure 1; Figure 3 shows the end of a rope, encapsulated in a protective material; Figure 4 shows a detail of an embodiment of the invention; and Figure 5 shows a further rope termination in accordance with the invention. With reference to Figures 1 and 2 , a rope 2 comprises a plurality of load bearing cores 4 surrounded optionally by a filter layer 6 and by a cover 8, preferably a braided outer cover 8. In this particular embodiment, the rope comprising 20 cores 4 arranged as four columns of five rows. The cores 4 may be termed sub-ropes by some in the art . To terminate the rope 2 , and as can be seen from Figure 2 , the end of each individual load bearing core 4 is spliced in a known manner to form a connecting eye 10. Each eye 10 is mounted over a respective load pin 12 which extends between spaced apart load plates 14. The load plates 14 are provided with aligned holes 16 to receive a load pin or the like for connection to another rope section, to a structure being moored or to an anchor, for example. The load plates 14 and load pins 12 are, in this embodiment, formed from a titanium alloy which gives the termination high strength and resistance to corrosion. As can be seen, four load pins 12 are provided in this embodiment, each receiving five core eyes 10. This arrangement transfers the load from the rope 2 very evenly into the side plates 14. This effect is enhanced by the arrangement of the load pins 12 in two rows, spaced apart in the axial direction of the rope. The staggered arrangement also keeps the transverse dimension of the termination relatively compact. The arrangement shown in Figures 1 and 2 is rather schematic and in practice the end 20 of the rope 2 is preferably encapsulated in a material such as polyurethane so as to fix the core eyes 10 in position relative to each other. In particular, after the core ends have been spliced, the cover 8 of the rope is milked back over each splice. The eyes 10 are then placed on a core in a mould (not shown) which is then filled with the encapsulating material. This solidifies to form a solid body 22 which, upon removal of the mould cores, leaves eye openings 24. This provides an arrangement which considerably facilitates assembly of the rope onto the load pins 12 and which also protects the ends of the rope 2. With reference to Figure 4, this illustrates one manner in which a load plate 14 may be secured to the load pins 12. In this embodiment, a side plate 30 receives first locking bolts 32 which fasten into the ends of the pins 12 and second locking bolts 34 which fasten into the load plate 14. The locking bolts 32, 34 and the side plate 30 are protected by a skid plate 36. With reference to Figure 5 , there is shown schematically a connector 44 manufactured in accordance with the principles of the present invention for connecting two ropes 40, 42. In this embodiment, the connector 44 is provided with eight load pins 46 supported between respective load plates 48. The four load pins 46 at the right- hand end 50 of the connector 44 receive the eyes 52 of the first rope cores 54 and the pins 46 at the left- hand end 56 of the connector 44 receive the eyes 58 of the other load bearing cores 60. The individual rope ends can be encapsulated in the manner shown in Figure 3 and the load pins 46 secured to the load plates 48 in the manner shown in Figure 4. In the various embodiments described above, the individual rope cores 4 can be manufactured in 3 , 4 or 6 strands twisted constructions or 8 or 12 strand braided constructions for example. The braided jacket could be manufactured from 16, 24 or 32 strand braids construction for example . Both the core and cover could be manufactured from a range of materials including polyester, nylon, high modulus polyethylene, polypropylene and other rope making fibres .

Claims

1. A rope termination, said rope comprising a plurality of load bearing cores, each said core being spliced to itself at its end to form a connecting eye, said termination further comprising a connector comprising a plurality of load bearing members, the connecting eyes of respective cores being arranged around designated load bearing members whereby the load is transmitted from said rope to said connector through a plurality of said load bearing members .

2. A rope termination as claimed in claim 1 wherein the load bearing members extend between respective supports.

3. A rope termination as claimed in claim 2 wherein a plurality of load pins extend between a pair of load plates . . A rope termination as claimed in claim 3 wherein one end of each load pin is formed integrally with one of the load plates.

5. A rope termination as claimed in claim 3 or 4 wherein at least one end of each load pin is be separate from and secured to both load plates.

6. A rope termination as claimed in claim 5 wherein a side plate is mounted over the load plate with fasteners extending into the load pins and the load plates .

7. A rope termination as claimed in claim 6 wherein the side plate is provided with a skid plate.

8. A rope termination as claimed in any preceding claim wherein the connector comprises connection means for connecting the support to a second component.

9. A rope termination as claimed in claim 8 wherein said connection means comprise a bore for receiving a load pin or the like.

10. A rope termination as claimed in claim 8 wherein said connection means comprises a second set of load bearing members for receiving connecting eyes of the load bearing cores of a second rope.

11. A rope termination as claimed in any preceding claim wherein the load bearing members and supports are manufactured from a high strength material which has good resistance to corrosion and sea water.

12. A rope termination as claimed in claim 11 wherein said material is a fibre composite, a titanium alloy or a high strength steel alloy.

13. A rope termination as claimed in any preceding claim wherein the load bearing members are arranged at different spacings from the end of the rope.

14. A rope termination as claimed in claim 13 wherein the load bearing members are arranged in rows spaced apart axially in the direction of the rope.

15. A rope termination as claimed in any preceding claim wherein more than one core is mounted over each load bearing member.

16. A rope termination as claimed in any preceding claim wherein the rope end is encapsulated in a material to provide a unitary body.

17. A rope termination, said rope comprising a plurality of cores, each said core being spliced to itself at its end to form a connecting eye, said core ends being encapsulated in a surrounding material to fix them in position relative to each other.

18. A rope termination as claimed in claim 16 or 17 wherein said encapsulating material is a polyurethane.

19. A rope termination as claimed in claim 16, 17 or 18 wherein said rope comprises a cover and said material also encapsulates a portion of that cover.

20. A method of terminating a rope, said rope having a plurality of cores, each said core being spliced to itself at its end to form a connecting eye, comprising placing said core ends in a mould with said eyes positioned over one or more mould cores, introducing an encapsulating material into the mould, allowing said encapsulating material to solidify, and removing the encapsulated rope termination from the mould and the mould core(s) .