Power Transmission Gear Wheel with Elastomeric Return

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Solution Overview

Problem

Traditional elastic return means in micro-mechanics and watchmaking, such as springs and shape memory materials, are difficult to manufacture reproducibly and require skilled labor, and their damping properties often counteract the goal of maintaining oscillations with minimal damping.

Innovation Solution

A power transmission mobile with a flexible wheel set having a variable geometry, comprising a rigid peripheral part and an elastic axial part connected by elastic blades or strips, allowing energy absorption, storage, and release during pivoting, effectively decoupling inertia and providing a constant torque to the escapement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional springs are used as elastic return means, then good longevity and high restoring torque are achieved, but manufacturing is difficult and requires skilled labor

Engineering Contradiction:
ImprovelongevityVSAvoidmanufacturing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces traditional metal springs with elastomeric material elements that provide elastic return forces. This substitution eliminates the need for precision spring manufacturing while maintaining the necessary mechanical functionality, thereby improving ease of manufacture without sacrificing reliability

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

Solution Approach 2:

The invention uses elastomeric materials with specific durometer ranges (e.g., 40-70 Shore A) to create flexible circuit board structures that combine flexibility with structural integrity. This material selection enables reliable elastic return behavior while simplifying manufacturing processes

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If shape memory materials like vulcanized rubber are used, then ease of manufacture is improved, but damping properties counteract oscillation maintenance

Engineering Contradiction:
Improvemanufacturing easeVSAvoidoscillation maintenance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent carefully selects elastomeric materials with specific durometer ranges (40-70 Shore A) and controls their physical parameters to achieve the right balance between flexibility and oscillation maintenance. By adjusting material hardness and geometric parameters, the design maintains oscillations while remaining easy to manufacture

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flexible circuit board incorporates elastic return means with locally optimized properties - certain regions have specific durometer values and thicknesses tailored to provide minimal damping while maintaining structural integrity and ease of manufacture

Inventive Principle:
Principle #3Local quality

3Force

If elastic return means are made rigid for high restoring torque, then torque is improved, but flexibility and adaptability are reduced

Engineering Contradiction:
Improverestoring torqueVSAvoidflexibility
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The patent creates dynamically adaptable elastic return means through flexible circuit boards that can bend and deform elastically. The elastomeric material properties allow the structure to adapt to varying mechanical stresses while maintaining sufficient restoring torque through optimized geometry and material selection

Inventive Principle:
Principle #15Dynamics

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 solution enhances the efficiency of micro-mechanical mechanisms by reducing the instantaneous torque peak during shocks and maintaining oscillations with minimal damping, protecting fragile components from damage and improving the performance of escapements in watch movements.

Implementation Method 1

elastic blades or strips, allowing energy absorption, storage, and release during pivoting

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

elastic return means being arranged to, as the case may be, absorb, store or release energy during an angular displacement in pivoting

Methodology Applied
Scientific EffectEnergy absorption: Absorption (physical)

Data Source

PatentEP2455821B2Power transmission gear wheel
Publication Date: 2018.11.14 NIVAROX FAR SA
  • EP2455821B2 patent drawingFigure 1
  • EP2455821B2 patent drawingFigure 2

AI summary

The mechanism (1) has rigid elements (200, 600) fixed to a different elements of movement, moved with respect to each other and pivoted around a pivoting axis (D). An elastic return unit (300) provides elastic connection between one of the rigid elements and an intermediate rigid element (400), and another elastic return unit (500) produces elastic connection between the intermediate rigid element and the other rigid element. The rigid elements, the elastic return units and the intermediate rigid element are coplanar on a plane and deformed on the plane. The intermediate rigid element is a balance felloe, and one of the rigid elements is a balance plate. The mechanism is made of micro-machinable material, silicon, silicon oxide, quartz, or one of compounds of micro-machinable material, silicon, silicon oxide and quartz.