Double Jacketed Wire Rope Fatigue Life
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Solution Overview
Problem
Conventional plastic impregnated wire ropes face issues with inconsistent plastic distribution, leading to steel-to-steel abrasion and reduced fatigue life due to strand-to-strand and strand-to-core contact during flexing, which existing solutions like core jacketing with wormings or spacers do not fully address.
Innovation Solution
A double-jacketed wire rope design featuring an inner plastic jacket over the independent wire rope core and an outer plastic jacket over the outer strands with wormings or spacers to maintain gaps between strands, ensuring consistent plastic filling and separation, thereby preventing contact and enhancing fatigue life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional plastic impregnation is used to provide cleanliness and minimize sheave wear, then the rope exterior is protected, but plastic distribution is uncontrolled and strand-to-strand contact occurs leading to abrasion
Solution Approach 1:
The invention divides the plastic protection system into two separate segments: an inner plastic jacket that fully encapsulates the core and an outer plastic impregnation that penetrates the outer strands. This segmentation allows each layer to perform its specific function - the inner jacket maintains core strand separation while the outer layer provides cleanliness and sheave protection, preventing the uncontrolled plastic distribution problems of conventional single-layer impregnation
Solution Approach 2:
The invention implements a nested structure where the inner plastic jacket is positioned inside the outer strands, and the outer plastic impregnation penetrates through the outer strands to reach the inner jacket. This nested arrangement ensures that plastic material is contained within defined boundaries, preventing strand-to-strand contact while maintaining full plastic coverage for cleanliness and abrasion resistance
2Duration of action of moving object
If core jacketing with wormings or spacers is used to maintain strand separation, then fatigue life is improved, but the rope is not fully plastic impregnated reducing cleanliness and sheave protection
Solution Approach 1:
The invention merges two previously separate solutions into a single integrated system: the core jacketing with wormings or spacers for strand separation and the outer plastic impregnation for cleanliness. By combining these approaches, the rope simultaneously achieves improved fatigue life through maintained strand separation and full plastic coverage for exterior protection, eliminating the need to choose between the two approaches
3Duration of action of moving object
If outer strand voids are filled with plastic material, then fatigue life increases, but the plastic filling falls off during rope flexing in use
Solution Approach 1:
The invention uses the inner plastic jacket as a flexible shell that provides a solid foundation for plastic filling. The outer plastic impregnation penetrates through the outer strands and bonds to this flexible shell, creating a layered structure where the plastic filling is mechanically anchored. This prevents the plastic material from falling off during rope flexing while maintaining the gap-filling function that extends fatigue life
Data Source
AI summary
A wire rope is provided which has an independent wire rope core (IWRC) covered by a plastic jacket. Outer strands are laid on this plastic jacket and wormings or spacers extend from the plastic jacket in between the outer strands to form gaps between the outer strands. Another jacket is provided over the outer strands which also fills the gaps between the outer strands. Both the IWRC and the outer strands are preferably lubricated. A method is also disclosed for manufacturing such wire rope.