Active Damping Counter-Spring for Watch Chiming

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Solution Overview

Problem

Existing watch striking mechanisms suffer from significant kinetic energy loss and potential rebound issues due to damping counter-springs, which reduce the acoustic level of the sound produced when the hammer strikes the gong.

Innovation Solution

The implementation of an active damping counter-spring mechanism, where the counter-spring is activated with a delay after the hammer strikes the gong, allowing the drive spring to retain energy and prevent rebound by pushing the hammer back to its rest position without initial slowdown, thus enhancing the acoustic level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a damping counter-spring is used to push back the hammer in a rest mode, then the hammer is maintained at a distance from the gong, but significant kinetic energy is lost during the striking process

Engineering Contradiction:
Improvehammer positioningVSAvoidkinetic energy loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The counter-spring is designed to be dynamically activated only after the hammer strikes the gong. During the striking phase, the counter-spring remains inactive, allowing the hammer to retain its kinetic energy. After the strike, the counter-spring activates to push the hammer back to its rest position, preventing rebound. This dynamic activation timing resolves the contradiction by maintaining positioning reliability only when needed without compromising striking energy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The drive spring is pre-loaded to store energy before the striking moment. When the hammer is released, the pre-loaded drive spring propels the hammer toward the gong with maximum kinetic energy. The counter-spring is simultaneously pre-positioned but inhibited from acting until after the strike, ensuring no energy loss during the critical striking phase while still providing the necessary rebound prevention.

Inventive Principle:
Principle #10Preliminary action

2Power

If the drive spring is pre-wound to increase striking force, then the acoustic level increases, but the counter-spring must be adjusted via eccentric to avoid rebound

Engineering Contradiction:
Improvestriking forceVSAvoidcounter-spring adjustment mechanism
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The problematic eccentric adjustment mechanism is completely removed from the design. Instead of using an eccentric to control counter-spring activation, the patent employs a direct mechanical linkage where the counter-spring is automatically activated by the hammer's motion after the strike. This extraction of the eccentric mechanism simplifies the device while maintaining the ability to prevent rebound through the counter-spring's automatic activation timing.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The counter-spring system is designed to be self-activating through the hammer's own motion. As the hammer completes its striking motion and begins to return, the counter-spring automatically engages and pushes the hammer back to its rest position without requiring external adjustment mechanisms. This self-service approach eliminates the need for complex eccentric adjustments while maintaining effective rebound prevention.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the counter-spring acts during the hammer's path to the gong, then the hammer is controlled, but the acoustic level of the sound is reduced

Engineering Contradiction:
Improvehammer controlVSAvoidacoustic level
Core Design Contradiction:
Ease of operationVSPower

Solution Approach 1:

The counter-spring operates in a periodic manner, remaining inactive during the approach phase and activating only after the strike. This periodic operation pattern allows the hammer to reach the gong with full kinetic energy for maximum acoustic output, while the counter-spring provides control and rebound prevention in the subsequent return phase. The temporal separation of functions resolves the contradiction between control and acoustic level.

Inventive Principle:
Principle #19Periodic action

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 effectively increases the acoustic level of the sound produced by maintaining the striking energy and preventing hammer rebound, resulting in improved sound quality and reduced energy loss during the striking process.

Implementation Method 1

A hammer drive spring of the mechanism may be configured as an elastic beam or leaf. This drive spring can be armed to drive said hammer against the gong

Methodology Applied
Scientific EffectElastic potential energy: Elasticity

Implementation Method 2

Said hammer is held away from the gong by said damping counter-spring in a rest mode

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 3

A hammer of the mechanism is rotatably mounted on the plate, for example near the gong holder, so as to strike the gong to make it vibrate

Methodology Applied
Scientific EffectImpact force: Impact Force

Data Source

PatentEP2362279B1Chiming mechanism of a watch with active buffer counter spring
Publication Date: 2019.05.08 MONTRES BREGUET SA
  • EP2362279B1 patent drawingFigure 1
  • EP2362279B1 patent drawingFigure 2A
  • EP2362279B1 patent drawingFigure 2B

AI summary

The mechanism has a damper counter spring (5) i.e. lever, maintaining a hammer (2) at distance from a gong (21) in a rest position. A driving spring (3) is armed to drive the hammer against the gong in a striking mode to produce acoustic sound. An activating unit i.e. metallic stopper, activates the damper counter spring in the striking mode with certain delay following strike of the hammer against the gong such that the counter spring pushes the hammer to the rest position after striking of the hammer against the gong. The spring is in a form of a spring blade or binder.