Watch Striking Hammer Flexure for Low-Play Sound Transfer

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Solution Overview

Problem

Existing watch striking mechanisms face challenges in maximizing the normal component of forces applied by the hammer to the vibrating element, leading to inefficiencies in sound production and control, while conventional pivots introduce mechanical play and require lubrication.

Innovation Solution

A watch movement with a striking mechanism featuring a hammer cantilevered by elastic blades forming a flexible guide, arranged in intersecting directions to maximize the normal component of forces and eliminate tangential components, reducing the number of parts and mechanical play.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pivots are used to constrain the hammer, then the hammer can be held in position, but mechanical play and lubrication requirements are introduced

Engineering Contradiction:
Improvehammer positioning stabilityVSAvoidmechanical play and lubrication requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the conventional pivot-based mechanical constraint system with an elastic blade-based flexible guide system. The elastic blades constrain the hammer through elastic deformation rather than mechanical contact, eliminating the need for pivots, lubrication, and complex mechanical joints while maintaining positioning stability and reducing mechanical play.

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

2Power

If the hammer strikes the vibrating element with high force, then sound production is enhanced, but the tangential component of forces increases friction and reduces efficiency

Engineering Contradiction:
Improvesound production efficiencyVSAvoidfriction losses from tangential forces
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent changes the geometric parameters of the flexible guide (blade arrangement, curvature, and orientation) to control the direction of the hammer's motion. By optimizing these parameters, the hammer's trajectory is adjusted so that the striking force is predominantly normal to the vibrating element's surface, maximizing the normal component of force while minimizing the tangential component, thus reducing friction and energy loss.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If multiple parts are used in the striking mechanism, then functionality is achieved, but the number of parts increases complexity and potential power loss

Engineering Contradiction:
Improvestriking mechanism functionalityVSAvoidnumber of parts
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges multiple functional components into the elastic blades, which simultaneously serve as the flexible guide, the constraint mechanism, and the power transmission element. This consolidation reduces the number of separate parts, simplifies the mechanism, and eliminates power losses associated with multiple interfaces and connections while maintaining full striking functionality.

Inventive Principle:
Principle #5Merging (Combining)

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

Enhances sound production efficiency and control by maximizing the normal force component, reducing mechanical play, and simplifying manufacturing with a single-unit design that minimizes power loss and size.

Implementation Method 1

a hammer (121) cantilevered from a structure of the watch movement by means of at least two elastic blades (122) forming a flexible guide

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4310604B1Timepiece movement comprising a striking mechanism provided with a flexure
Publication Date: 2025.12.24 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP4310604B1 patent drawingFigure 1~3

AI summary

The invention relates to a watch movement comprising a striking mechanism (10) of a watch having a vibrating element (11) and a striking device (120) of said vibrating element (11) comprising a hammer (121) fixed in cantilever to a structure of the watch movement by means of blades of a flexible guide (122), said blades (122) being arranged both so as to extend in intersecting directions to a point materializing an instantaneous center of rotation C disposed on an axis T tangent to the vibrating element (11).