Cladded Rope Drive Polymer Sheath Friction and Wear

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Solution Overview

Problem

Existing rope drives for cranes and similar applications face challenges with high system costs, reduced lifespan of components, and complex maintenance due to the lack of effective lubrication and the use of non-coated wire ropes.

Innovation Solution

A rope drive system featuring a drum and a train organ with at least one supporting element partially surrounded by a polymer-based coat, which enhances the lifespan of components, reduces maintenance complexity, and lowers system costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If wire ropes are coated or sheathed with plastic to protect against mechanical damage, severe external wear, or corrosion, then the service life of the rope is extended, but the monitoring of wire breaks becomes impossible

Engineering Contradiction:
Improveservice life of the ropeVSAvoidmonitoring of wire breaks
Core Design Contradiction:
Duration of action of stationary objectVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies a plastic coating or sheath to the wire rope that changes color or exhibits visual indicators when wire breaks occur internally. This allows the coating to serve both protective and monitoring functions, resolving the contradiction between extending service life through coating and maintaining detectability of wire breaks.

Inventive Principle:
Principle #32Color changes

2Duration of action of stationary object

If lubricants are used to reduce friction between the grooves of the rope pulleys or drums and the rope, then the service life is extended, but the system complexity and maintenance requirements increase

Engineering Contradiction:
Improveservice lifeVSAvoidsystem complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent incorporates self-lubricating properties into the plastic coating or sheath material itself, allowing the rope to reduce friction with pulleys and drums without requiring external lubricant application systems. This eliminates the complexity of lubrication systems while maintaining extended service life benefits.

Inventive Principle:
Principle #25Self-service

3Duration of action of stationary object

If thick outer wires are used to protect against mechanical damage, severe external wear, or corrosion, then the service life is extended, but the friction between the grooves of the rope pulleys or drums and the rope increases

Engineering Contradiction:
Improveservice lifeVSAvoidfriction
Core Design Contradiction:
Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite structure combining thick protective outer wires with a plastic coating or sheath. The plastic layer provides a low-friction surface that compensates for the increased friction from thicker wires, while maintaining the protective benefits against mechanical damage, wear, and corrosion.

Inventive Principle:
Principle #40Composite materials

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 use of a coated train organ in rope drives extends the lifespan of the train organ and other components up to 10 times compared to non-coated systems, simplifies maintenance, and reduces system costs.

Implementation Method 1

The support element is at least partially surrounded by a casing (22) comprising a polymer. At least part of the casing (22) represents the support surface of the traction element.

Methodology Applied
Scientific EffectProtective coating: Coatings

Data Source

PatentEP3541737B1Rope drive with cladded traction device
Publication Date: 2025.05.07 BRUGG LIFTING AG
  • EP3541737B1 patent drawingFigure 1a~3
  • EP3541737B1 patent drawingFigure 4a~5
  • EP3541737B1 patent drawingFigure 6a~6b

AI summary

The invention relates to a cable drive which, in particular, is suitable for cranes or mass-produced hoists and which comprises a drum (1) and a traction element (2a; 2; 2a), which runs on the drum (1). The traction element (2a; 2; 2a) comprises at least one load-bearing element (21; 22; 21a-21d) and is at least partly surrounded by a sheath (22), which preferably consists of a polymer, in particular preferably of a thermoplastic and/or elastomer. At least part of the sheath (22) constitutes the contact surface of the traction element (2a; 2; 2a).