Escapement Mechanism With Buckling Leaf Spring

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Solution Overview

Problem

Existing escapement mechanisms in mechanical watchmaking are large in size, require delicate adjustments, and suffer from significant friction losses, leading to energy wastage and reduced movement efficiency.

Innovation Solution

A compact escapement mechanism with a reduced-length leaf spring, direct interaction of the winding rocker at the point of inflection, and a single escapement wheel set to minimize friction and energy loss, utilizing silicon materials and a monolithic design for rockers and pallets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional escapement mechanism with leaf spring and dual rocker arms is used, then the oscillations of the balance wheel can be maintained, but the mechanism becomes large in size and complex in structure

Engineering Contradiction:
Improveoscillation maintenanceVSAvoidmechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of the leaf spring and the detent lever into a single integrated component. The detent lever is transformed into a flexible blade with buckling capability that performs both the energy storage function of the leaf spring and the detent function, eliminating the need for separate components and reducing overall mechanism complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The flexible blade with buckling is designed to perform multiple functions simultaneously: it acts as an energy storage element through buckling deformation, serves as a detent mechanism through its geometric shape, and provides the impulse transmission path to the balance wheel, thereby reducing the number of dedicated components needed

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Use of energy by moving object

If a traditional escapement mechanism with dual escape wheels and symmetrical rockers is used, then energy can be accumulated and released, but significant friction losses occur and energy efficiency decreases

Engineering Contradiction:
Improveenergy accumulation and releaseVSAvoidfriction losses
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent extracts and eliminates the second escape wheel and its associated pallet fork from the mechanism. The single escape wheel design with the flexible blade's integrated detent function removes unnecessary friction-generating components while preserving the essential energy accumulation and release functions through the buckling mechanism

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The flexible blade's geometric shape and buckling behavior provide automatic detent and release functions without requiring additional locking or controlling components. The mechanism uses its own structural properties to control the energy release timing, reducing the need for extra friction-generating interaction points

Inventive Principle:
Principle #25Self-service

3Reliability

If a traditional escapement mechanism with two symmetrical driving elements is used, then the balance wheel oscillations can be driven, but delicate adjustment is required and manufacturing becomes difficult

Engineering Contradiction:
Improvebalance wheel oscillationVSAvoidadjustment and manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent transitions from a symmetrical dual-escape-wheel design to an asymmetrical single-escape-wheel configuration with the flexible blade positioned at an angle. This asymmetrical arrangement eliminates the need for precise symmetrical alignment and adjustment of two separate driving elements, simplifying both manufacturing and assembly while maintaining reliable oscillation driving

Inventive Principle:
Principle #4Asymmetry

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 reduces the size of the mechanism, simplifies the structure, minimizes friction, and enhances energy transmission efficiency, maintaining consistent oscillations over the power reserve while reducing the need for precise adjustments.

Implementation Method 1

via a leaf spring operating in buckling around an inflection point. The leaf spring is capable of accumulating energy from the driving source between two pulses

Methodology Applied
Scientific EffectBuckling:

Implementation Method 2

The leaf spring 2 is capable, by means of a winding rocker 3 and a release rocker 4, of accumulating the energy from the driving source during a winding phase, of remaining in a wound state during a rest phase and of releasing the accumulated energy to said oscillating regulator during a pulse phase

Methodology Applied
Scientific EffectElastic energy storage: Elasticity

Implementation Method 3

the leaf spring 2 left its initial stable state, corresponding to second-mode buckling, and deformed under the action of the winding lever 3 until it reached a metastable state close to an unstable state, corresponding to fourth-mode buckling

Methodology Applied
Scientific EffectMechanical deformation: Deformation

Implementation Method 4

the detent rocker 4 pivots, acting on the leaf spring 2, which then suddenly swings from its unstable position to a stable state corresponding to a second-mode buckling. During the change of state of the leaf spring 2, it also acts on the detent rocker 4, thus transferring the energy accumulated during the winding of the leaf spring 2 to the balance wheel 1 via the fork

Methodology Applied
Scientific EffectMechanical force transmission: Mechanical Force

Data Source

PatentEP3485332B1Escapement mechanism
Publication Date: 2022.01.12 SOWIND
  • EP3485332B1 patent drawingFigure 1
  • EP3485332B1 patent drawingFigure 2
  • EP3485332B1 patent drawingFigure 3~4

AI summary

The invention relates to an escapement mechanism (100) which is designed to transmit impulses of mechanical energy from a drive source to an oscillating regulator (200) of a timepiece via a strip spring (300) which acts by buckling about an inflection point (I), said strip spring (300) being able to accumulate the energy emitted by the drive source between two impulses and to transmit this to the oscillating regulator, at each impulse, by means of a winding lever (700) and a detent lever (500) which are able to rotate about an axis (A) and are designed to interact with the strip spring (300) and with at least one escapement wheel (800a) that receives the energy from the drive source, so as to block rotation thereof intermittently. The mechanism is characterised in that one end of the strip spring (300) is positioned on the axis of rotation (A) of the detent lever.