Unidirectional Wheel Clockwork Mechanism for Compact Timepiece

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Solution Overview

Problem

Existing clockwork mechanisms require bulky and expensive differential mechanisms to control unidirectional wheel sets, which is inefficient and costly, especially for systems with multiple inputs.

Innovation Solution

A clockwork set with a unidirectional wheel comprising a shaft, a pinion, and two coaxial wheels connected by elastic return means or springs that exert different frictional forces depending on the direction of pivoting, preventing torque transmission to opposing wheels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a differential mechanism is used to control unidirectional wheel sets, then directional control is achieved, but the device becomes bulky and expensive

Engineering Contradiction:

Improvedirectional controlVSAvoidbulkiness and cost

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of directional control from the complex differential mechanism and implements it through a simplified unidirectional wheel assembly. The unidirectional wheel (82, 86) with elastic return means (84, 88) provides the necessary directional control by allowing rotation in only one direction, eliminating the need for bulky differential mechanisms while maintaining the core functionality of controlling wheel sets based on rotation direction.

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of operation

If elastic return means are used to connect wheels to shaft, then unidirectional operation is achieved, but friction force must be precisely controlled

Engineering Contradiction:

Improveunidirectional operationVSAvoidfriction force control

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent utilizes parameter changes in the elastic return means (84, 88) to achieve the desired friction characteristics. By carefully selecting the elastic properties, pre-load forces, and geometric parameters of the springs, the system achieves reliable unidirectional operation with controlled friction. The elastic means are designed to exert sufficient friction to prevent reverse rotation while allowing smooth forward rotation, resolving the contradiction between operational reliability and manufacturing precision requirements.

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

This solution enables a compact, efficient, and cost-effective unidirectional wheel set operation without play, preventing untimely force feedback and minimizing backlash, suitable for both manual and automatic movements.

Implementation Method 1

first elastic return means in rotation or at least a first spring constituting first disengaging means and which exert on said first wheel a friction force

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

first elastic return means in rotation or at least a first spring constituting first disengaging means

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP2871534B1Timepiece mobile with unidirectional wheels

Publication Date: 2017.01.04 ETA SA MFG HORLOGERE SUISSE

AI summary

A unidirectional wheel clockwork mechanism (8) comprising a shaft (80) carrying a pinion (81) and at least one first wheel (82) coaxial with said pinion (81) and pivotally mounted on said shaft (80). Said first wheel (82) is connected to said shaft (80) by first means of elastic rotational return or at least a first spring (84) constituting first disengagement means (91) and which exert a frictional force on said first wheel (82).