Concentric Spring Energy Source for Timepiece Striking Torque

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Solution Overview

Problem

Existing energy sources for striking mechanisms in timepieces, typically single springs, face challenges in maintaining consistent chime frequency and regularity, especially at maximum stroke points like 12:59 p.m. and 12:45 p.m., due to limitations in torque distribution and space constraints, leading to deteriorating working conditions and adjustment issues.

Innovation Solution

The use of two springs wound in the same direction in concentric spirals, allowing for improved torque distribution and adjustable torque through parallel or series connections, with one spring partially wound to optimize the number of turns and reduce the blade height/thickness ratio, enabling a more constant and adjustable striking torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a single spring with large number of winding turns and thin blade is used to increase torque, then the torque is sufficient, but the height/thickness ratio becomes too high causing deteriorating working conditions

Engineering Contradiction:
ImprovetorqueVSAvoidworking conditions
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The single spring is divided into two separate springs (first spring and second spring) that are wound in opposite directions. Each spring contributes to the total torque, allowing sufficient torque to be generated without requiring an excessively high height/thickness ratio in each individual spring, thereby maintaining reliable working conditions.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single spring is used to drive the striking mechanism, then the structure is simple, but the chime frequency varies significantly during maximum strokes at 12:59 p.m. and 12:45 p.m.

Engineering Contradiction:
ImprovestructureVSAvoidchime frequency
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The single spring is segmented into two springs wound in opposite directions, each contributing to torque distribution. This segmentation allows for more uniform torque delivery throughout the striking sequence, maintaining stable chime frequency even during maximum strokes at 12:59 p.m. and 12:45 p.m.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a调节 device that can adjust the number of winding turns of the springs, thereby changing the torque parameters. This allows optimization of the torque distribution to maintain constant chime frequency across all striking positions, including the critical 12:59 p.m. and 12:45 p.m. maximum strokes.

Inventive Principle:
Principle #35Parameter changes

3Force

If two springs wound in opposite directions are used as described in US Patent 249,845, then the torque distribution improves, but the device complexity increases with separate barrel shafts

Engineering Contradiction:
Improvetorque distributionVSAvoidbarrel shafts
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The two springs are mounted on a common barrel shaft instead of having separate barrel shafts as in US Patent 249,845. This merging of the mounting structure reduces device complexity while maintaining the benefit of opposite-direction winding for improved torque distribution. The first and second springs are secured to the barrel shaft in a simplified configuration.

Inventive Principle:
Principle #5Merging (Combining)

4Force

If the height of the spring blade is increased to provide sufficient torque, then the torque is adequate, but the space available is insufficient especially when placed between the two hammers

Engineering Contradiction:
ImprovetorqueVSAvoidspace
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The torque requirement is segmented between two springs instead of relying on a single tall spring. Each spring can have reduced height while collectively providing the necessary torque, allowing the energy source to fit within the limited space between the two hammers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of increasing the height of the spring blade in one dimension, the patent uses two springs wound in opposite directions, effectively utilizing the radial dimension and creating a compact arrangement that fits within the available space between the hammers while maintaining sufficient torque.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration enhances the consistency and adjustability of the striking torque, maintaining a high-quality ringtone with reduced volume occupation, allowing for precise control over the ringing frequency and minimizing the need for torque adjustments.

Implementation Method 1

an elastic member arranged to generate a torque, winding means of said elastic member

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The elastic member comprises two springs wound in the same direction in concentric spirals

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2488921B1Energy source for a striking mechanism, and timepiece provided with such an energy source
Publication Date: 2013.10.30 COMPLITIME SA
  • EP2488921B1 patent drawingFigure 1~2
  • EP2488921B1 patent drawingFigure 3~4

AI summary

The invention relates to an energy source for a repeater striking mechanism for a timepiece, including a resilient member arranged so as to generate a torque, winding means (24, 54) for said resilient member, and a kinematic linking means (46) for applying said torque to the members of the striking mechanism so as to provide striking. According to the invention, the resilient member comprises two springs (38, 40) wound in the same direction in concentric spirals, stacked and arranged so as to apply said torque to the kinematic linking means (46).