Elastomer Coupling for Flexible Cable Drawing Rods

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Solution Overview

Problem

Existing devices for pulling cables into tubular bodies with narrow radii are limited by the relative bending stiffness of the rod element and draw-in spring tip, making it difficult to traverse curves with small radii without compromising the flexibility of the system.

Innovation Solution

A device featuring a coupling element with a receptacle aligned along the longitudinal axis, made of elastomer, which captively connects the rod element and allows for the transmission of tensile forces through the entire casing, combined with limited bending elasticity to facilitate passage through narrow radii without compromising flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a threaded rod and threaded sleeve coupling is used to transmit large tensile forces, then the tensile force transmission capability is improved, but the bending stiffness increases and the ability to traverse narrow radii deteriorates

Engineering Contradiction:
Improvetensile force transmission capabilityVSAvoidability to traverse narrow radii
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent changes the material parameter of the coupling element from rigid (metal threaded rod and sleeve) to flexible (elastomer), while maintaining the tensile force transmission capability through the elastomeric material's elastic properties. This allows the coupling element to bend around narrow radii while still transmitting the required tensile forces.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite structure where the coupling element is made of elastomer material that combines flexibility for bending with sufficient tensile strength for force transmission. The rod element with plastic sheathing and glass fiber core is also a composite structure that provides both flexibility and strength.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If the draw-in spring tip is designed for flexibility to pass through narrow radii, then the adaptability to traverse curves is improved, but the tensile force transmission capability deteriorates

Engineering Contradiction:
Improveflexibility to pass through narrow radiiVSAvoidtensile force transmission capability
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent changes the material parameter of the coupling element to elastomer, which provides both the required flexibility for traversing narrow radii and sufficient tensile strength for force transmission. The elastomeric material's elastic modulus is selected to balance these two requirements.

Inventive Principle:
Principle #35Parameter changes

3Strength

If a long threaded rod is used to transmit large tensile forces, then the tensile strength is improved, but the relative bending stiffness increases and flexibility deteriorates

Engineering Contradiction:
Improvetensile strengthVSAvoidflexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent changes the material parameter from rigid metal to flexible elastomer for the coupling element. This allows the element to maintain tensile strength while being sufficiently flexible to bend around curves in the pipe, eliminating the need for a long rigid threaded rod.

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

Enables error-free traversal of narrow radii in empty pipes while maintaining the flexibility of the rod and coupling elements, ensuring reliable operation even in longer pipes.

Implementation Method 1

the casing being made of an elastomer, that the coupling element in the casing has a receptacle aligned in the longitudinal axis direction of the casing, in which the rod element engages

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the coupling element has at least limited bending elasticity. The flexural elasticity ensures that the coupling element moves back to its original extent after passing through a radius

Methodology Applied
Scientific EffectElastic recovery: Elastic Recovery

Data Source

PatentEP2590279B1Device for drawing in a flexible element
Publication Date: 2015.08.12 KATIMEX CIELKER
  • EP2590279B1 patent drawingFigure 1~3
  • EP2590279B1 patent drawingFigure 4~5
  • EP2590279B1 patent drawingFigure 6

AI summary

The apparatus has a shear-rigid and flexurally elastic rod element (1) e.g. glass fiber rod, and a coupling element (4) arranged at an end of the rod element, where the rod element and the coupling element comprise a casing (7). The casing is partially formed in a traction-force-transmitting manner. The coupling element comprises limited bending elasticity, and the casing is formed from elastomer. The casing interconnects a core and the rod element and/or the core and a connection element (6). Projections are formed as ring elements that are fixedly set on the core.