Foam-Core Fiber-Reinforced Cable Drum for High Rope Loads

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Solution Overview

Problem

Existing cable drums made of steel or cast materials are heavy, which is disadvantageous in weight-sensitive applications, and alternative materials like honeycomb structures produced by selective laser melting are prone to cracking and distortion, and are expensive.

Innovation Solution

A rope drum with a multi-layered structure comprising fiber-reinforced composite material for the drum shell and end plates, incorporating a foam core and stiffening ribs, which provides lightweight stability and resistance to compressive stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If steel or cast material is used for the drum shell, then strength and stability are improved, but weight increases

Engineering Contradiction:
ImprovestrengthVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The drum shell is constructed using composite materials combining a foam core with fiber-reinforced plastic layers (such as carbon fiber or glass fiber). This composite structure provides high strength-to-weight ratio, maintaining the required mechanical strength while significantly reducing the overall weight compared to solid steel construction.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The drum shell employs varying wall thicknesses and fiber orientations in different regions to optimize strength where needed while minimizing material usage. The fiber reinforcement is concentrated in areas subject to highest stress, allowing weight reduction in less critical areas.

Inventive Principle:
Principle #3Local quality

2Weight of moving object

If honeycomb structure is used to reduce weight, then weight is reduced, but manufacturing complexity and cost increase

Engineering Contradiction:
ImproveweightVSAvoidmanufacturing complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

A foam core is used instead of a hollow honeycomb structure. The foam provides lightweight properties while being simpler to manufacture through injection molding or foam injection processes, eliminating the complexity of creating and assembling hollow cellular structures.

Inventive Principle:
Principle #31Porous materials

3Weight of moving object

If foam core is used to reduce weight, then weight is reduced, but resistance to compressive stresses decreases

Engineering Contradiction:
ImproveweightVSAvoidresistance to compressive stresses
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The foam core is combined with outer layers of fiber-reinforced plastic that provide the necessary compressive strength. The foam serves as a lightweight core while the fiber-reinforced shells bear the compressive loads from cable winding, creating a composite structure where each material performs its optimal function.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The fiber reinforcement is strategically oriented and distributed to provide maximum compressive resistance where cable loads are applied, while the foam core provides lightweight bulk. The wall thickness and fiber density are optimized locally to match the stress distribution pattern.

Inventive Principle:
Principle #3Local quality

4Stability of the object's composition

If multi-layered structure with foam core is used, then weight is reduced and stability is improved, but manufacturing precision requirements increase

Engineering Contradiction:
ImprovestabilityVSAvoidmanufacturing precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The multi-layered structure is manufactured as an integrated composite component in a single molding process, where the foam core and fiber-reinforced layers are combined simultaneously. This eliminates the need for separate assembly steps and reduces the accumulation of tolerances that would result from joining multiple pre-manufactured parts.

Inventive Principle:
Principle #5Merging (Combining)

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 solution achieves a lightweight, stable, and cost-effective rope drum capable of withstanding high rope loads, reducing weight and manufacturing costs while maintaining structural integrity.

Implementation Method 1

considerable compressive stresses occur on the cable drum due to the cable being wound onto it under load

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

the drum shell and/or the end plates are made of fiber-reinforced composite material

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 3

a multi-layered structure with at least two walls made of fiber-reinforced composite material, which are spaced apart from each other and connected to each other by an intermediate foam core

Methodology Applied
Scientific EffectFoam: Foam

Data Source

PatentEP3883877B1Cable drum for a cable winch and method for production thereof
Publication Date: 2025.10.29 LIEBHERR COMPONENTS BIBERACH GMBH
  • EP3883877B1 patent drawingFigure 1
  • EP3883877B1 patent drawingFigure 2
  • EP3883877B1 patent drawingFigure 3

AI summary

The present invention relates to a cable drum for a cable winch of a cable drive, having a drum shell and two flanged wheels which adjoin the drum shell at the ends, wherein the drum shell and/or the flanged wheels are produced from fiber-reinforced composite material, wherein the drum shell and/or the flanged wheels have a multi-shell structure having at least two walls made of fiber-reinforced composite material, which walls are spaced apart from each other and connected to each other by a foam core.