Long lived synthetic rope for powered blocks

Abstract

Disclosed is a method for producing a high strength synthetic strength member containing rope and a resultant rope, comprising multiple layers of twisted and braided yarns, wherein individual sheaths enclosing individual strands are of a material such as HMPE, PTFE or UHMWPE with a lower decomposition temperature than the material of said strands being aramid, the method comprising subjecting parts of the rope to heat and tension thereby pre-stretching and creating a non-uniform or non-round shape of said strands, further choosing a combination of braid and twist angles as well as braid compressive forces to accommodate specific strength and elongation relation between the individual rope layers.

1 . A method for forming a synthetic rope ( 1 ), the method having steps of:
 a) providing a core ( 3 ) formed of at least a first synthetic substance and selecting for the first synthetic substance a thermoplastic substance;   b) enclosing the core within at least a flow shield capable of retaining within the flow shield at least most and preferably all of the first synthetic substance when the first synthetic substance is in a semi-liquid phase;   c) providing several individual primary strands ( 19 ) formed of fibers formed of at least a second synthetic substance and selecting for the fibers mainly and preferably exclusively fibers that are Aramid fibers;   
       the method characterized by steps of:
 d) forming from a third synthetic substance at least several individual sheaths ( 21 ) where at least a sheath ( 21 ) is formed about and enclosing at least one of the several of the individual primary strands ( 19 ) formed of the second synthetic substance, so that at least some and preferably all of the individual primary strands ( 19 ) formed of the second synthetic substance are each enclosed by at least one of the individual sheaths ( 21 ) formed of the third synthetic substance, where the third synthetic substance forming at least some of the sheaths ( 21 ) has a lower decomposition temperature than does the second synthetic substance; 
 e) next, forming a hollow braided strength member ( 7 ) about the core ( 3 ) from several of the individual primary strands ( 19 ), where at least some and preferably all of the individual primary strands ( 19 ) used in forming the hollow braided strength member ( 7 ) have at least a sheath ( 21 ); 
 f) subjecting the strength member to tension and heat so as to cause the core to experience a non-solid phase and so as to cause the strength member and the core to become compacted and elongated; followed by cooling both at least the strength member and the core under tension so as to cause the strength member and the core to become permanently compacted and permanently elongated; and 
 g) enclosing the strength member within an outer sheath ( 8 ), 
 
       whereas a rope having at least a strength member formed at least mainly of synthetic fibers is produced. 
     
     
         2 . The method of  claim 1  further characterized by selecting for the third synthetic substance a substance that is less brittle than is the second synthetic substance. 
     
     
         3 . The method of  claim 2  further characterized by selecting to form at least one and preferably all of the individual sheaths ( 21 ) with a braided construction. 
     
     
         4 . The method of  claim 3  further characterized by selecting to form at least one of the individual braided sheaths ( 21 ) comprising fibers forming the braided construction forming the braided sheath. 
     
     
         5 . The method of  claim 4  further characterized by selecting fibers comprising HMPE. 
     
     
         6 . The method of  claim 4  further characterized by selecting fibers comprising PTFE. 
     
     
         7 . The method of  claim 5  characterized by the further step of selecting to also form the outer sheath ( 8 ) with a hollow braided construction, and by selecting to adhere the hollow braided strength member ( 7 ) to the hollow braided outer sheath ( 8 ) by steps of: selecting to situate at least a fourth synthetic substance in a flowable phase onto the exterior surface of several of the individual sheaths ( 21 ) formed of the third synthetic substance where such fourth synthetic substance is, when in a set and/or solid state, an elastic and adhesive substance; followed by forming a hollow braided outer sheath ( 8 ) about the hollow braided strength member ( 7 ) and selecting to form the hollow braided outer sheath ( 8 ) compressing against the exterior surfaces of at least portions of several of the inner individual sheaths ( 21 ) formed of the third synthetic substance. 
     
     
         8 . The method of  claim 6  characterized by the further step of selecting to also form the outer sheath ( 8 ) with a hollow braided construction, and by selecting to adhere the hollow braided strength member ( 7 ) to the hollow braided outer sheath ( 8 ) by steps of: selecting to situate at least a fourth synthetic substance in a flowable phase onto the exterior surface of several of the individual sheaths ( 21 ) formed of the third synthetic substance where such fourth synthetic substance is, when in a set and/or solid state, an elastic and adhesive substance; followed by forming a hollow braided outer sheath ( 8 ) about the hollow braided strength member ( 7 ) and selecting to form the hollow braided outer sheath ( 8 ) compressing against the exterior surfaces of at least portions of several of the inner individual sheaths ( 21 ) formed of the third synthetic substance. 
     
     
         9 . The method of  claim 7  further comprising selecting to apply a constrictive force by most and preferably by all sheaths ( 21 ) to at least some and preferably any primary strand ( 19 ) that is a constrictive force that is sufficiently low so that each of the primary strands ( 19 ) is deformed during manufacturing of the rope and adopts a non-circular cross section in the finished rope product when viewed in a plane that is perpendicular to the long dimension of the rope. 
     
     
         10 . The method of  claim 8  further comprising selecting to apply a constrictive force by most and preferably by all sheaths ( 21 ) to at least some and preferably any primary strand ( 19 ) that is a constrictive force that is sufficiently low so that each of the primary strands ( 19 ) is deformed during manufacturing of the rope and adopts a non-circular cross section in the finished rope product when viewed in a plane that is perpendicular to the long dimension of the rope. 
     
     
         11 . The method of  claim 9  further comprising selecting to form at least some of the individual braided sheaths ( 21 ) from flattened fibers. 
     
     
         12 . The method of  claim 10  further comprising selecting to form at least some of the individual braided sheaths ( 21 ) form flattened fibers. 
     
     
         13 . The method of  claim 11  further comprising selecting to braid the sheath from the flattened fibers in such fashion that at least some of the flattened fibers are untwisted about their long axis. 
     
     
         14 . The method of  claim 12  further comprising selecting to braid the sheath from the flattened fibers in such fashion that at least some of the flattened fibers are untwisted about their long axis. 
     
     
         15 . The method of  claim 2  further characterized by selecting to form at least one and preferably all of the individual sheaths ( 21 ) comprising a wrapped tape. 
     
     
         16 . The method of  claim 15  further characterized by selecting a tape comprising HMPE. 
     
     
         17 . The method of  claim 15  further characterized by selecting a tape comprising PTFE. 
     
     
         18 . The method of  claim 15  further comprising selecting to apply a constrictive force by most and preferably by all sheaths ( 21 ) to at least some and preferably any primary strand ( 19 ) enclosed by any sheath ( 21 ) that is a constrictive force that is sufficiently low so that each of the primary strands ( 19 ) is deformed during manufacturing of the rope and adopts a non-circular cross section in the finished rope product when viewed in a plane that is perpendicular to the long dimension of the rope. 
     
     
         19 . The method of  claim 16  further comprising selecting to apply a constrictive force by most and preferably by all sheaths ( 21 ) to at least some and preferably any primary strand ( 19 ) that is a constrictive force that is sufficiently low so that each of the primary strands ( 19 ) is deformed during manufacturing of the rope and adopts a non-circular cross section in the finished rope product when viewed in a plane that is perpendicular to the long dimension of the rope. 
     
     
         20 . The method of  claim 17  further comprising selecting to apply a constrictive force by most and preferably by all sheaths ( 21 ) to at least some and preferably any primary strand ( 19 ) that is a constrictive force that is sufficiently low so that each of the primary strands ( 19 ) is deformed during manufacturing of the rope and adopts a non-circular cross section in the finished rope product when viewed in a plane that is perpendicular to the long dimension of the rope. 
     
     
         21 . The method of  claim 18  characterized by the further step of selecting to also form the outer sheath ( 8 ) with a hollow braided construction, any by selecting to adhere the hollow braided strength member ( 7 ) to the hollow braided outer sheath ( 8 ) by steps of: selecting to situate at least a fourth synthetic substance in a flowable phase onto the exterior surface of several of the individual sheaths ( 21 ) formed of the third synthetic substance where such fourth synthetic substance is, when in a set and/or solid state, an elastic and adhesive substance; followed by forming a hollow braided outer sheath ( 8 ) about the hollow braided strength member ( 7 ) and selecting to form the hollow braided outer sheath ( 8 ) compressing against the exterior surfaces of at least portions of several of the inner individual sheaths ( 21 ) formed of the third synthetic substance. 
     
     
         22 . The method of  claim 19  characterized by the further step of selecting to also form the outer sheath ( 8 ) with a hollow braided construction, and by selecting to adhere the hollow braided strength member ( 7 ) to the hollow braided outer sheath ( 8 ) by steps of: selecting to situate at least a fourth synthetic substance in a flowable phase onto the exterior surface of several of the individual sheaths ( 21 ) formed of the third synthetic substance where such fourth synthetic substance is, when in a set and/or solid state, an elastic and adhesive substance; followed by forming a hollow braided outer sheath ( 8 ) about the hollow braided strength member ( 7 ) and selecting to form the hollow braided outer sheath ( 8 ) compressing against the exterior surfaces of at least portions of several of the inner individual sheaths ( 21 ) formed of the third synthetic substance. 
     
     
         23 . The method of  claim 20  characterized by the further step of selecting to also form the outer sheath ( 8 ) with a hollow braided construction, and by selecting to adhere the hollow braided strength member ( 7 ) to the hollow braided outer sheath ( 8 ) by steps of: selecting to situate at least a fourth synthetic substance in a flowable phase onto the exterior surface of several of the individual sheaths ( 21 ) formed of the third synthetic substance where such fourth synthetic substance is, when in a set and/or solid state, an elastic and adhesive substance; followed by forming a hollow braided outer sheath ( 8 ) about the hollow braided strength member ( 7 ) and selecting to form the hollow braided out sheath ( 8 ) compressing against the exterior surfaces of at least portions of several of the inner individual sheaths ( 21 ) formed of the third synthetic substance. 
     
     
         24 . The method of  claim 1  characterized by the further step of stranding the primary strands ( 19 ) directly from fibres and/or filaments. 
     
     
         25 . The method of  claim 2  characterized by the further step of stranding the primary strands ( 19 ) directly from fibres and/or filaments. 
     
     
         26 . The method of  claim 18  characterized by the further step of stranding the primary strands ( 19 ) directly from fibres and/or filaments. 
     
     
         27 . The method of  claim 19  characterized by the further step of stranding the primary strands ( 19 ) directly from fibres and/or filaments. 
     
     
         28 . The method of  claim 20  characterized by the further step of stranding the primary strands ( 19 ) directly from fibres and/or filaments. 
     
     
         29 . The method of  claim 1  wherein the rope has a longer service life when used with powered blocks and/or sheaves in comparison to known synthetic strength membered ropes. 
     
     
         30 . The method of  claim 2  wherein the rope has a longer service life when used with powered blocks and/or sheaves in comparison to known synthetic strength membered ropes. 
     
     
         31 . A rope having a solid core ( 3 ) formed of at a first synthetic substance that mainly is a thermoplastic substance, and having a strength member ( 7 ) formed of primary strands ( 19 ) formed of at least a second synthetic substance and braided together with a hollow braided construction about the solid core ( 3 ), the primary strands ( 19 ) formed mainly of the second synthetic substance comprising mainly Aramid filaments,
 the rope characterized in that: a third synthetic substance forms several individual sheaths ( 21 ) where at least one of the several individual sheaths ( 21 ) encloses at least one the individual primary strands ( 19 ) formed of the second synthetic substance, so that at least some and preferably all of the individual primary strands ( 19 ) are each enclosed by at least one of the individual sheaths ( 21 ); where the third synthetic substance has a lower decomposition temperature than does the second synthetic substance.   
     
     
         32 . The rope of  claim 31  where the third synthetic substance is less brittle than the second synthetic substance. 
     
     
         33 . The rope of  claim 31  where the third synthetic substance is more elastic than the second synthetic substance. 
     
     
         34 . The rope of  claim 31  where an elastic adhesive substance formed from a fourth synthetic substance adheres interior surfaces of a hollow braided outer sheath ( 8 ) to portions of exterior surfaces of at least several of the inner sheaths ( 21 ) formed of the third synthetic substance, where the third synthetic substance is more elastic than the second synthetic substance and less elastic than the fourth synthetic substance. 
     
     
         35 . The rope of  claim 32  where an elastic adhesive substance formed from a fourth synthetic substance adheres interior surfaces of a hollow braided outer sheath ( 8 ) to portions of exterior surfaces of at least several of the inner sheaths ( 21 ) formed of the third synthetic substance, where the third synthetic substance is more elastic than the second synthetic substance and less elastic than the fourth synthetic substance. 
     
     
         36 . The rope of  claim 35  where an elastic adhesive substance formed from a fourth synthetic substance adheres interior surfaces of a hollow braided outer sheath ( 8 ) to portions of exterior surfaces of at least several of the inner sheaths ( 21 ) formed of the third synthetic substance, where the third synthetic substance is more elastic than the second synthetic substance and less elastic than the fourth synthetic substance. 
     
     
         37 . The rope of  claim 31  where at least one and preferably all of the individual sheaths ( 21 ) is formed with a braided construction. 
     
     
         38 . The rope of  claim 37  where the braided construction comprises fibers. 
     
     
         39 . The rope of  claim 38  wherein the fibers comprise PTFE. 
     
     
         40 . The rope of  claim 39  wherein the fibers comprise HMPE. 
     
     
         41 . The rope of  claim 40  wherein the HMPE fibers comprise a flattened form. 
     
     
         42 . The rope of  claim 41  wherein the HMPE fibers comprising a flattened form include at least some fibers that are untwisted about their long axis. 
     
     
         43 . The rope of  claim 31  where at least some and preferably all of the individual sheaths ( 21 ) comprise a wrapped tape. 
     
     
         44 . The rope of  claim 43  wherein the wrapped tape comprises PTFE. 
     
     
         45 . The rope of  claim 43  wherein the wrapped tape comprises HMPE. 
     
     
         46 . The rope of  claim 31  where at least the majority of strands ( 19 ) comprise a non-circular cross section when viewed in a plane that is perpendicular to the long dimension of the rope. 
     
     
         47 . The rope of  claim 37  where at least the majority of strands ( 19 ) comprise a non-circular cross section when viewed in a plane that is perpendicular to the long dimension of the rope. 
     
     
         48 . The rope of  claim 38  where at least the majority of strands ( 19 ) comprise a non-circular cross section when viewed in a plane that is perpendicular to the long dimension of the rope. 
     
     
         49 . The rope of  claim 46  wherein at least the majority of primary strands ( 19 ) are stranded directly from fibers and/or filaments. 
     
     
         50 . The rope of  claim 47  wherein at least the majority of primary strands ( 19 ) are stranded directly from fibers and/or filaments. 
     
     
         51 . The rope of  claim 48  wherein at least the majority of primary strands ( 19 ) are stranded directly from fibers and/or filaments. 
     
     
         52 . The rope of  claim 49  wherein longevity of the service life of the rope when used with powered blocks and/or sheaves with loading forces of at least two thousand kilograms and up to two thousand tonnes is greater in comparison to prior known synthetic ropes. 
     
     
         53 . The rope of  claim 50  wherein longevity of the service life of the rope when used with powered blocks and/or sheaves with loading forces of at least two thousand kilograms and up to two thousand tonnes is greater in comparison to prior known synthetic ropes. 
     
     
         54 . The rope of  claim 51  wherein longevity of the service life of the rope when used with powered blocks and/or sheaves with loading forces of at least two thousand kilograms and up to two thousand tonnes is greater in comparison to prior known synthetic ropes.