Seamless Rope Drum Shell Rolling for High Compressive Loads

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Solution Overview

Problem

Existing cable winches face challenges in manufacturing large, heavy-duty drums that can withstand high compressive stresses without restrictions on wall thickness, diameter, and material, as traditional methods like welding or drawing limit size and introduce defects and uneven stress distribution.

Innovation Solution

A seamless cable drum shell is manufactured by rolling a single-piece annular workpiece blank, allowing for arbitrary adaptation of diameter and wall thickness, with a non-cutting cable groove profile formed during rolling, eliminating weld seams and enhancing mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional welding or drawing methods are used to manufacture cable drum shells, then manufacturing complexity is reduced, but the drum shell develops defects and uneven stress distribution that limit size and strength

Engineering Contradiction:
Improvedrum shell strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The manufacturing process is segmented into distinct stages: heating the annular blank, rolling it into a drum shell, and forming cable grooves. This segmentation allows each stage to be optimized independently, achieving high strength through controlled thermal and mechanical processes while maintaining manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The drum shell manufacturing utilizes parameter changes by heating the material to alter its properties during forming, and by controlling rolling parameters to achieve desired wall thickness and strength characteristics without weld seams or drawing defects.

Inventive Principle:
Principle #35Parameter changes

2Force

If larger dimensions and wall thicknesses are used to withstand high compressive stresses, then the drum shell can handle higher loads, but manufacturing costs and complexity increase

Engineering Contradiction:
Improvecompressive stress resistanceVSAvoidmanufacturing cost
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

By heating the annular blank before rolling, the material becomes more formable, allowing large dimensions and thick walls to be achieved without requiring complex multi-step forming operations or expensive specialized equipment. The thermal parameter change enables cost-effective manufacturing of high-strength, large-diameter drums.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The traditional mechanical drawing or welding processes are replaced with a thermal-mechanical rolling process. This substitution eliminates the need for complex welding procedures or high-force drawing operations, reducing manufacturing complexity and cost while enabling production of drums with superior strength characteristics.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If chip-cutting methods are used to create cable grooves, then groove precision is achieved, but material is removed and structural integrity is reduced

Engineering Contradiction:
Improvegroove precisionVSAvoidstructural integrity
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The chip-cutting mechanical removal process is replaced with a forming process that displaces material to create the groove profile. This substitution eliminates material removal and associated structural weakening while maintaining groove precision through controlled plastic deformation of the drum shell material.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The potential harm of material removal is converted into benefit by using forming instead. The material that would be discarded as chips is instead redistributed within the groove structure, maintaining mass and structural integrity while achieving the required groove geometry for proper cable winding.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

This method enables the production of large, high-strength cable winches with improved stress distribution and reduced material defects, allowing for larger dimensions and unit weights without increased costs, while avoiding warping and uneven heat input.

Implementation Method 1

heating the material, in particular the annular workpiece blank

Methodology Applied
Scientific EffectThermal energy input: Heating

Implementation Method 2

rolling the material, in particular the annular workpiece blank, by means of rolling rolls into a drum shell

Methodology Applied
Scientific EffectMechanical compression: Compression

Implementation Method 3

The drum shell is seamlessly rolled from an annular workpiece blank. This annular workpiece blank is formed into the drum shell with the required wall thickness and diameter by a rolling process

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3691811B1Rope drum and method for the production thereof
Publication Date: 2023.07.12 LIEBHERR COMPONENTS BIBERACH GMBH
  • EP3691811B1 patent drawingFigure 1
  • EP3691811B1 patent drawingFigure 2
  • EP3691811B1 patent drawingFigure 3

AI summary

The present invention relates to rope drums (1) for winding and unwinding ropes, having a drum shell (3), to which end disks (4) are fastened at the end faces, and to rope winches having such rope drums. The invention also relates to a method for producing such a rope drum. According to the invention, the drum shell is seamlessly rolled from an annular workpiece blank by means of a rope groove profile (19) embossed in a non-cutting manner.