Dynamic cable having improved properties and process and plant for manufacturing such a cable

Abstract

A cable includes a plurality of strands around a core, where the space between the strands and/or between core and strands is filled with a polyurethane-based polymer material. The cable is produced by depositing the polymer material over the core and/or strands with a coating device a certain distance upstream of the cabling point. The polymer's composition and coating point are determined so that the strands are placed around the core when the polymerization of the compound is sufficiently advanced so that the polymer formed is in a viscoplastic state suitable to form an approximately continuous adherent coating layer, but still sufficiently fluid to insinuate into the interstices between core and strands and between the strands.

1 . A process for manufacturing a dynamic cable comprising a plurality of strands stranded around a core, the spaces between strands and/or between core and strands being at least partly filled with a polymer material, according to which process the cable is formed by depositing, around a running core, a plurality of strands wound in a helix, wherein a polymerizable compound is deposited, on the run, over the core and/or the strands at a coating point at a certain distance upstream from the cabling point in the direction in which the core runs, said compound comprising a prepolymer and a polymerization accelerator, the composition of said compound and the distance from the coating point being determined so that the strands are wound around the core when the polymerization that the deposited compound is undergoing is sufficiently advanced so that the polymer formed is in a viscoplastic state suitable for forming a coating layer which is pasty but still sufficiently fluid to flow into the interstices between core and strands, and between strands, and wherein the polymerization is completed only when the cable is formed.  
     
     
         2 . The process as claimed in  claim 1 , wherein the polymerizable compound is deposited only over the core.  
     
     
         3 . The process as claimed in  claim 1 , wherein the polymerizable compound is deposited by coating jointly the core and the strands.  
     
     
         4 . The process as claimed in  claim 1 , wherein the polymer material is based on polyurethane.  
     
     
         5 . The process as claimed in  claim 1 , wherein the polymerizable compound is produced just before coating, by mixing a prepolymer containing isocyanates with a polymerization accelerator in predetermined proportions.  
     
     
         6 . A cabling plant comprising means for making a core of a cable run and a cabling head for depositing a plurality of strands in a helix around the core, and comprising coating means for depositing a polymerizable compound over the core and/or the strands, wherein said coating means are at a certain distance upstream of the cabling head with respect to the direction in which the core runs and wherein they comprise: 
 a prepolymer reservoir,    a polymerization accelerator reservoir and    an injection head with a mixing chamber connected to said reservoirs,    said coating means being controlled so as to deposit, over the running core and/or strands, a layer of said compound thus obtained by mixing.    
     
     
         7 . The cabling plant as claimed in  claim 6 , wherein said coating means comprise an injection head surrounding the core and controlled so as to deposit said layer over the core.  
     
     
         8 . A cable comprising a plurality of strands cabled around a core, the spaces between core and strands being filled with a polyurethane-based polymer material, where in said material is a compound obtained by mixing a prepolymer with a polymerization accelerator and wherein it has been deposited at least around the core during cabling and wherein it has been insinuated between the strands and/or between the constituent wires.