Fibril-Reinforced Cable Sheath for Heavy-Duty Stress

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Solution Overview

Problem

Heavy-duty cables used in applications like crane trolleys face mechanical stress and environmental harshness, leading to fatigue, wear, and rigidity issues due to their bulky structure and metallic discontinuous layers, which increase weight, cost, and limit design flexibility.

Innovation Solution

A fibril-reinforced polymeric matrix is used as a continuous outer sheath to replace the traditional composite sheath, reducing weight, size, and rigidity, and simplifying the manufacturing process by eliminating the need for multiple extrusion steps and discontinuous layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a discontinuous reinforcing layer (metallic braid) is used in the composite sheath, then mechanical strength is improved, but weight and size increase

Engineering Contradiction:
Improvemechanical strengthVSAvoidcable weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent changes the physical state and distribution of reinforcing elements from discrete metallic braids to continuously distributed fibrils within the polymeric matrix. This parameter change transforms the reinforcement architecture, achieving mechanical strength through dispersed fibrillar reinforcement rather than concentrated discontinuous layers, thereby reducing weight while maintaining strength

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite polymeric-fibril material system where short fibrils are dispersed and embedded within a polymeric matrix during extrusion. This composite approach creates a homogeneous reinforced material that combines the flexibility and lightness of polymers with the strength contribution of fibrils, eliminating the need for heavy metallic discontinuous layers

Inventive Principle:
Principle #40Composite materials

2Strength

If a discontinuous reinforcing layer is used in the composite sheath, then mechanical strength is improved, but the cable structure becomes bulkier

Engineering Contradiction:
Improvemechanical strengthVSAvoidcable volume
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The patent transforms the reinforcement architecture from thick discontinuous layers to finely dispersed fibrils throughout the matrix volume. This parameter change in reinforcement distribution allows strength to be achieved with much lower volumetric content of reinforcing material, reducing the overall cable volume and eliminating bulkiness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies reinforcement locally at the micro-scale through fibril dispersion rather than globally through thick discontinuous layers. Each fibril provides localized reinforcement where needed, and the collective effect of numerous fibrils throughout the matrix achieves overall strength without requiring large volumes of reinforcing material

Inventive Principle:
Principle #3Local quality

3Strength

If multiple extrusion steps are used to create composite sheath with discontinuous layer, then mechanical strength is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvemechanical strengthVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the reinforcement function and the sheath formation function into a single extrusion process. By incorporating fibrils directly into the polymeric matrix during one extrusion step, the patent eliminates the need for separate steps to apply discontinuous reinforcing layers, thereby simplifying manufacturing equipment and processes while maintaining mechanical strength

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal extrusion process that simultaneously achieves sheath formation, reinforcement incorporation, and surface finishing in one operation. The single extrusion step performs multiple functions that traditionally required separate processes, reducing device complexity and streamlining manufacturing

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Strength

If discontinuous metallic layers are used in the composite sheath, then mechanical strength is improved, but production cost increases

Engineering Contradiction:
Improvemechanical strengthVSAvoidmaterial cost
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent replaces expensive metallic reinforcing materials with cost-effective polymeric fibrils that can be produced and incorporated at lower material cost. The fibrils provide sufficient reinforcement for the application, eliminating the need for costly metallic layers while reducing overall material expenditure

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the material composition parameters from metallic to polymeric fibrils, transforming the reinforcement system to use cheaper, easily processable materials. This parameter change in material selection reduces both material cost and processing cost while maintaining the necessary mechanical strength through effective fibril-matrix composite action

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The fibril-reinforced polymeric matrix provides mechanical strengthening while reducing the weight and size of the cables, improving flexibility and design options, and lowering production costs by simplifying the manufacturing process.

Implementation Method 1

a reinforcing layer (6) comprising a fibril reinforced polymeric matrix

Methodology Applied
Scientific EffectFibril reinforcement: Composite Materials

Data Source

PatentEP2021407B1Cable and process for manufacturing the same
Publication Date: 2016.03.09 PRYSMIAN SPA
  • EP2021407B1 patent drawingFigure 1~5
  • EP2021407B1 patent drawingFigure 1a~6

AI summary

A cable for applications which entails heavy mechanical stresses and/or harsh environmental conditions comprises at least one core (2) having at least one transmissive element (3) and an outer sheath (5) disposed in radially external position with respect to the core (2) . The outer sheath (5) comprises a reinforcing layer (6) comprising a fibril reinforced polymeric matrix. A process for manufacturing such a cable comprises the steps of providing a core (2) having at least a transmissive element (3) , providing a first compound of fibrils and a matrix and applying the first compound around the core (2) to form the reinforcing layer (6) comprising the fibril reinforced polymeric matrix. The invention deals also with the use of fibrils for the manufacturing of a coating layer for a cable.