Plastic impregnated wire rope with internal separating bands

Abstract

A plastic impregnated wire rope is provided with plastic bands between its core and its outer strands so as to prevent contact between the wires of the core and those of the outer strands during flexing of the rope. This produces a substantial increase in the life of the rope. The method for manufacturing such rope involves wrapping plastic bands on the core just prior to laying outer strands on the core and on top of the plastic bands. Thereafter, the so formed rope is impregnated with molten plastic, which is then allowed to solidify.

1 . A plastic impregnated wire rope having a wire rope core and outer strands wound around said core, characterized in that said wire rope is provided with plastic bands between the core and the outer strands, said bands having such size and shape as to essentially prevent contact between the wires of the core and those of the outer strands during operation of the rope, but without substantially impeding the flow of molten plastic into and within the wire rope during plastic impregnation of said wire rope.  
     
     
         2 . A plastic impregnated wire rope according to  claim 1 , in which the plastic bands are made of a thermoplastic material.  
     
     
         3 . A plastic impregnated wire rope according to  claim 2 , in which the thermoplastic material of the bands is a thermoplastic elastomer.  
     
     
         4 . A plastic impregnated wire rope according to  claim 3 , in which the thermoplastic elastomer is polypropylene.  
     
     
         5 . A plastic impregnated wire rope according to  claim 1 , in which the plastic bands have an arcuate face in contact with the outer strands.  
     
     
         6 . A plastic impregnated wire rope according to  claim 1 , which comprises full plastic impregnation of said wire rope.  
     
     
         7 . A plastic impregnated wire rope according to  claim 1 , which comprises partial plastic impregnation of said wire rope.  
     
     
         8 . Method of producing a plastic impregnated wire rope which comprises: 
 (a) forming a wire rope core and moving it towards a closing station;    (b) forming outer strands for the wire rope and moving them towards the closing station;    (c) winding the outer strands around the core at the closing station;    (d) wrapping plastic bands of predetermined size and shape over the wire rope core at the entrance to the closing station, prior to winding of the outer strands around said core, said plastic bands being laid on the core so as to provide controlled plastic separation between the outer strands and the core, while leaving sufficient spacing between the bands to allow flow of molten plastic therethrough; and    (e) after closing the wire rope with the plastic bands laid between the outer strands and the core, impregnating said wire rope with a molten plastic material and subsequently allowing said plastic material to solidify.    
     
     
         9 . Method according to  claim 8 , wherein wrapping of the plastic bands over the wire rope core is done with the help of a hollow frusto-conical device mounted and rotating around the core at the entrance of the closing station, said device having slots on its internal surface for guiding the plastic bands towards the core and allowing them to be laid on the core in a predetermined manner.  
     
     
         10 . Method according to  claim 9 , wherein the bands are laid on the core so as to follow the same lay as the outer strands.  
     
     
         11 . Method according to  claim 8 , wherein the wire rope core being formed is an independent wire rope core.  
     
     
         12 . Method according to  claim 8 , wherein the wire rope core being formed is a lubricated core.  
     
     
         13 . Method according to  claim 8 , wherein the outer strands being formed are lubricated strands.  
     
     
         14 . Method according to  claim 8 , wherein eight outer strands are used together with eight plastic bands on which said outer strands are positioned.  
     
     
         15 . Method according to  claim 8 , wherein plastic impregnation of the wire rope is carried out as a separate operation after forming the non-impregnated rope with plastic bands laid between the core and the outer strands.