Elastomeric Band Tensioner for Compact High-Force Applications

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Solution Overview

Problem

Existing tensioning devices that utilize steel spring assemblies are complex, heavy, and require numerous additional elements, making them bulky and costly, while alternatives with elastomeric materials lack the capability to achieve high pretensioning forces with significant expansion paths.

Innovation Solution

A spring and tensioning element composed of elastically stretchable bands connected in series, guided around a rigid support body and articulations, allowing for adjustable spring rate and compact design, with options for reinforcement and modular assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If steel spring assemblies are used to achieve high pretensioning forces, then high security against breakage is improved, but device complexity and weight increase significantly

Engineering Contradiction:
Improvesecurity against breakageVSAvoidconstruction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the essential tensioning function from complex steel spring assemblies and implements it using simple elastomeric bands that can be guided around support bodies and articulations. This removes unnecessary components while maintaining the core tensioning capability, directly reducing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces durable but complex steel springs with simpler elastomeric bands that achieve the same functional effect. These bands are easier to manufacture and install, trading some perceived durability for significant gains in simplicity and cost-effectiveness.

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

2Reliability

If steel spring assemblies are used to achieve high pretensioning forces, then high security against breakage is improved, but weight increases significantly

Engineering Contradiction:
Improvesecurity against breakageVSAvoidtensioning device weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The invention substitutes traditional mechanical steel spring systems with elastomeric material-based tensioning elements. This material substitution dramatically reduces weight while maintaining the ability to generate and maintain high pretensioning forces through elastic deformation.

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

Solution Approach 2:

The patent changes the fundamental material parameter from metal to elastomer, exploiting the high elastic properties of rubber-like materials. This allows achieving the same tensioning effect with much lighter components, as elastomeric bands can store significant elastic energy at low weight.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If elastomeric bands are used for tensioning, then weight and complexity are reduced, but capability to achieve high pretensioning forces with significant expansion path is limited

Engineering Contradiction:
Improveconstruction simplicityVSAvoidpretensioning force capability
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The invention guides the elastomeric bands around support bodies and articulations in a nested configuration, creating multiple contact points and effective leverage. This geometric arrangement amplifies the force-generating capability of the elastomeric material, enabling high pretensioning forces despite the material's inherent limitations.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from linear spring elements to bands that operate in multiple dimensions by wrapping around support bodies. This creates effective mechanical advantage through the geometry of the band path, allowing significant force multiplication and expansion path capability that overcomes the limitations of simple elastomeric tensioning.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Force

If steel spring assemblies are used, then high pretensioning forces are achieved, but installation space requirements increase

Engineering Contradiction:
Improvepretensioning forceVSAvoidinstallation space
Core Design Contradiction:
ForceVSArea of stationary object

Solution Approach 1:

The invention segments the tensioning function into distributed elastomeric bands that can be routed through multiple small contact points (support bodies and articulations) rather than requiring a single large spring assembly. This distributes the force-generating function across compact elements, dramatically reducing the overall installation footprint.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bands are guided around support bodies in a nested arrangement where multiple functional elements occupy overlapping spatial volumes. This allows the tensioning system to generate high forces while occupying minimal installation space, as the bands effectively nest around the support structures rather than requiring separate clearance for each component.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 provides a lightweight, compact, and cost-effective tensioning module with adjustable spring rate, suitable for various applications, offering improved installation space, weight, and cost efficiency while maintaining high pretensioning forces and spring deflection.

Implementation Method 1

the tape loops being guided around the support body and the articulations in such a way that when the distance between the articulations increases due to external influences, elastic expansion occurs of the slings takes place and so a tensile spring force is built up

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3121478B1Spring and tensioning element
Publication Date: 2018.08.29 CONTITECH ANTRIEBSSYSTEME GMBH
  • EP3121478B1 patent drawingFigure 1
  • EP3121478B1 patent drawingFigure 2
  • EP3121478B1 patent drawingFigure 3a~3b

AI summary

Spring and tensioning element (1) with several resiliently stretchable bands, preferably bands or belts made of a stretchable elastomer material, which are at least partially connected in series with respect to their spring properties, wherein the bands are designed as endless elongated band loops (2, 3, 4) and are each guided on one side around a rigid elongated support body (5) arranged within the band loops (2, 3, 4) and on the other side around a pivot point (6, 7) supported at least by at least two spaced-apart ends of the support body (5) and movable relative to the support body (5), wherein each of the band loops (2, 3, 4) wraps around the support body (5) on the side opposite the pivot point (6, 7) it wraps around and has sections (T) running substantially parallel to each other between the wraps, wherein the band loops (2, 3, 4) are guided around the Support body (5) and the linkages (6,7) are led to the conclusion that if the distance (A) between the pivots (6, 7) is increased by external influences, an elastic stretching of the webbing loops (2, 3, 4) occurs and thus a tensile spring force is built up between the pivots (6, 7).