Flexible Guide Angular Travel in Mechanical Oscillators

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Solution Overview

Problem

Mechanical clock oscillators with flexible guides and crossed blades face limitations in angular travel, making them incompatible with conventional escapement mechanisms, and existing solutions for increasing angular travel are not isochronous.

Innovation Solution

Optimizing the combination of apex angle and the ratio of distance to length for the flexible blades to achieve isochronous pivots within specific ranges, allowing for greater angular travel compatible with existing escapement mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flexible guides with crossed blades are used in mechanical oscillators, then pivot friction is eliminated and quality factor is improved, but angular stroke is limited to 10°-20° which is incompatible with conventional escapement mechanisms

Engineering Contradiction:
Improvequality factorVSAvoidangular stroke
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent applies parameter changes by optimizing the geometric parameters of the flexible guide structure. Specifically, it adjusts the ratio between the distance from the fixed point to the crossing point (D) and the total blade length (L), setting D/L between 0.15 and 0.85, and controls the apex angle α between blade directions to be ≤60°. These parameter optimizations enable the flexible guide to achieve both high quality factor and sufficient angular stroke for escapement compatibility.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If the angular stroke of flexible guide pivots is increased to match balance wheel amplitude, then compatibility with escapement mechanisms is achieved, but isochronism is lost

Engineering Contradiction:
Improveangular strokeVSAvoidisochronism
Core Design Contradiction:
Length of moving objectVSStability of the object's composition

Solution Approach 1:

The patent resolves this contradiction through precise parameter optimization. By setting the distance-to-length ratio D/L between 0.15 and 0.85 and the apex angle α ≤60°, the flexible guide achieves both large angular stroke (≥30°) and maintains isochronous oscillation characteristics. This parameter range ensures that the elastic deformation remains within the linear regime while providing sufficient travel range.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs dynamic analysis to ensure isochronism is maintained across the extended angular range. The flexible guide is designed so that its elastic characteristics remain consistent throughout the oscillation cycle, ensuring that the period of oscillation remains independent of amplitude. This dynamic consistency allows the oscillator to work effectively with escapement mechanisms while maintaining timekeeping accuracy.

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

The solution enables mechanical oscillators with angular travel exceeding 30°, making them compatible with standard mechanical escapements, while maintaining isochronism, thus enhancing the functionality of mechanical timepieces.

Implementation Method 1

at least two first flexible blades (31, 32), which support said second solid inertial element (5) and are arranged to return it to a rest position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3451073B1Timepiece oscillator having flexible guides with wide angular travel
Publication Date: 2021.08.04 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP3451073B1 patent drawingFigure 1~3
  • EP3451073B1 patent drawingFigure 4~9
  • EP3451073B1 patent drawingFigure 6~8

AI summary

A mechanical clockwork oscillator (100) comprising, between a first element (4) and a second inertial element (5), two separate flexible blades (31; 32) returning the inertial element (5) to a rest position in a plane of oscillation, the projections of these blades intersecting, in the rest position, at a point (P), through which passes the pivot axis of the second solid inertial element (5), the fixed ends of the blades with the first element (4) and the second inertial element (5) defining two directions along which each blade (31; 32) has a free length (L1; L2) between its fixed ends, and an axial distance (D1; D2) between the pivot axis and the furthest of its fixed ends, and, for each blade (31; 32), the fixed-end ratio (D1/L1; D2/L2) is between 0 and 1, and the angle at vertex (a) at the intersection of the blade directions is less than 70°.