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(11) | EP 0 020 130 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Ropes |
| (57) A rope assembly comprises a plurality of ropes encased in a braided sheath, in which
each rope is formed of at least two strands. One rope assembly of the invention comprises 18 3- strand laid ropes encased in a sheath of 24 millimetres nominal diameter. This sheath consists of 16 plaits each having 18 yams per plait. Each sheath yam is made of 4.5 lea staple which is spun at a twist of 3.0 turns per inch. Each of the encased ropes forming the core is made of yams which are based on I.C.I. fibres Type 125 continuous filament polyester yam. The rope assembly has an average breaking load of 15.34 tonnes and a flex angle of 60°. The weight of the finished rope at check load is 41.6 kilogrammes per 100 metres. In another rope assembly of the invention four 3- strand laid ropes 2 are encased in a braided sheath 4. |
TECHNICAL FIELD
[0002] In this specification by "rope" is meant an elongate member formed by twisting, laying, weaving or otherwise entwining a plurality of strands.
[0003] The invention provides a rope assembly comprising a plurality of ropes encased in a braided sheath, in which each rope is formed of at least two strands.
DESCRIPTION
[0004] In one rope assembly of the invention, eighteen 3-strand laid ropes are encased in a sheath of 24 millimetres nominal diameter consisting of 16 plaits each having 18 yarns per plait.. Each sheath yarn is made of 4.4 lea staple which is spun at a twist of 3.0 turns per inch. Each of the encased ropes forming the core is made of yarns which are based on ICI fibres Type 125 continuous filament polyester yarn. The rope assembly of the embodiment has an average breaking load of 15.34 tonnes and a flex angle of 60°. The weight of the finished rope at check load is 41.6 kilogrammes per 100 metres.
[0005] The rope assembly has a stitch length of 80 millimetres at zero load, and of 84.6 millimetres at . check load.
[0006] The following table 1 sets out the data for 24 millimetre and 32 millimetre diameter rope assemblies constituting examples of the invention.
[0007] The encased ropes forming the core of rope assemblies of the invention can be based on a wide range of man-made, synthetic and natural fibres. Because the core ropes according to this invention are laid rather than twisted there is only a low variation of tension between the constituent yarns of each core rope. This method of construction is thus particularly suitable for constituent yarns having low extensibility such as organic polyamids.
[0008] In a further embodiment of the invention the core ropes are constructed from "Aramid" organic polyamid yarns each covered with a polyester cover. One example of such a yarn is that sold under the trade name Du Pont Kevlar PC.
[0009] The following table 2 sets out the data for 8mm and 24mm diameter rope assemblies constituting further examples of the invention.
[0010] The accompanying sketch illustrates one rope assembly of the invention; this assembly comprises four three-strand laid ropes 2 encased in a braided sheath 4.
[0011] It is to be understood that the invention includes within its scope a rope assembly including two or more ropes encased in a braided sheath, and that each encased rope may be formed by entwining two or more strands.
[0012] Advantages of the aforementioned embodiment of the invention include:-
(1) Alternate encased core ropes of the rope assembly may be of opposite hand; i.e. alternative ropes may be formed of strands of S and Z twists. This reduces the tendency for the rope assembly to rotate when extended.
(2) The construction of the rope assembly provides it with improved flexibility.
(3) Rope is stored by being wound on reels of standard size. Consequently the greater the rope diameter the shorter the length of rope that can be stored on a reel of any given size. Because the rope assembly of the invention includes a plurality of core ropes, each core , rope is of smaller diameter than previously proposed constructions in which only a single core rope is used. Consequently, the rope assembly of the invention can be constructed in considerably longer lengths than previously proposed rope assemblies using a single core rope, and
(4) The plurality of core ropes included in the rope assembly of the invention ensures that the rope assembly possesses a greater strength and breaking load than previously proposed single core rope assemblies.