Bicycle Belt Tension Roller Layout for Direct Spring Force Transfer

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Solution Overview

Problem

Existing bicycle belt tensioning devices are inefficient in transmitting forces to the tension roller, requiring strong springs and complex lever mechanisms, which limits effective belt tensioning.

Innovation Solution

A bicycle frame element with a belt tensioning device featuring a tension roller connected to a swivel lever via a receiving element, with a tensioning element arranged between the lever and the frame, utilizing an elastic clamping element and a tension spring for efficient power transmission, allowing the tension roller to press against the belt's underside, where no tensile forces act, ensuring reliable and automatic belt tensioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a conventional lever mechanism with a tension spring is used, then the belt tensioning device can maintain belt tension, but only a small portion of the spring forces are transmitted to the tensioning pulley, requiring a relatively strong spring

Engineering Contradiction:
Improvespring force transmissionVSAvoidlever mechanism complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

Instead of having the spring press against a lever arm that mechanically disadvantages force transmission, the patent inverts the approach by having the spring act directly on the tensioning pulley through a simplified connection. The spring force is applied in a direction that maximizes its effect on the belt, eliminating the need for complex lever mechanisms and improving force transmission efficiency.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts the essential function of force transmission from the complex lever mechanism and implements it through a simplified direct connection between the spring and tensioning pulley. By removing unnecessary intermediate lever elements, the design achieves better force transmission with reduced mechanical complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Extent of automation

If a tension spring is provided between the lever and the frame, then automatic tensioning can be achieved, but the lever mechanism becomes relatively complex to accommodate the tension spring

Engineering Contradiction:
Improveautomatic tensioningVSAvoidlever mechanism complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent extracts the automatic tensioning function from the complex lever mechanism and implements it through a simplified spring-pulley system. The spring is directly connected to the tensioning pulley, eliminating the need for complex lever arms while maintaining automatic tensioning capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a lever mechanism to translate spring force into belt tension, the patent inverts the approach by having the spring act directly on the tensioning pulley. This inversion simplifies the mechanism while preserving automatic tensioning functionality.

Inventive Principle:
Principle #13The other way round (Inversion)

3Force

If the tensioning roller presses against the belt from above, then belt tensioning can be achieved, but the structure requires more space and may interfere with other bicycle components

Engineering Contradiction:
Improvebelt tensioning forceVSAvoidspace requirement
Core Design Contradiction:
ForceVSArea of stationary object

Solution Approach 1:

Instead of pressing the tensioning roller against the top of the belt, the patent inverts the approach by pressing against the underside of the belt. This inversion allows for a more compact arrangement that reduces interference with other bicycle components while maintaining effective belt tensioning.

Inventive Principle:
Principle #13The other way round (Inversion)

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 configuration ensures reliable and automatic belt tensioning with improved power transmission, reducing the need for frequent adjustments and enhancing the performance of bicycles with electric motor support by maintaining optimal belt tension.

Implementation Method 1

the clamping element is an elastic element, and in particular, the clamping element is designed as an elastic element

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a tension spring is provided between the lever and the seat tube

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP4007862B1Belt tensioning device
Publication Date: 2024.08.28 RTI SPORTS VERTRIEB VON SPORTARTIKELN GMBH
  • EP4007862B1 patent drawingFigure 1~2
  • EP4007862B1 patent drawingFigure 3

AI summary

The invention relates to a belt tensioning device for drive belts of a bicycle frame, which comprises a tensioning roller (30). The tensioning roller (30) is rotatably supported via a receiving element (28) by a pivoting lever (26). The pivoting lever (26) is pivotably fastened via a holding element (24) to the bicycle frame. Furthermore, a tensioning element (32) is connected to the pivoting lever (26) and the bicycle frame. In order to provide a good force transmission, the tensioning element (32) is connected to the pivoting lever (26) between the holding element (24) and the receiving element (28).