Shock-absorber Hairspring Stud Holder for Watch Oscillators

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Solution Overview

Problem

Current methods for assembling the balance-spring oscillator in watch movements fail to prevent radial displacement of the outer end of the spiral spring relative to its inner end, leading to chronometric defects and isochronism degradation during benchmarking operations.

Innovation Solution

A shock absorber body with a clamping element, such as screws, is used to press a surface of the bridge against a binding element, immobilizing it and preventing radial displacement while allowing angular displacement, ensuring the outer end of the hairspring remains concentric with the balance shaft during benchmarking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a deformable arm stud holder is used to allow angular movement of the balance spring outer end, then adjustment flexibility is improved, but radial displacement and parallelism distortion occur leading to chronometric errors

Engineering Contradiction:
Improveadjustment flexibilityVSAvoidchronometric precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The stud holder is divided into two functional segments: a radially fixed portion that maintains precise positioning, and an angularly adjustable portion that allows timing adjustments. This segmentation enables independent control of radial stability and angular adjustability, resolving the contradiction between adjustment flexibility and chronometric precision.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If an elastic split ring stud holder is used to maintain angular position, then centering is partially improved, but deformation during assembly occurs making precise positioning difficult

Engineering Contradiction:
Improvecentering stabilityVSAvoidstud position precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The design incorporates pre-assembled stud holders that are pre-positioned and fixed radially before the balance spring is attached. This beforehand positioning prevents deformation-related positioning errors during assembly, as the radial position is established prior to any elastic deformation occurring during spring installation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Measurement precision

If additional components are added for fine adjustment, then alignment precision is improved, but device complexity increases

Engineering Contradiction:
Improvealignment precisionVSAvoidassembly complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The adjustment function is merged into the stud holder itself through its ability to rotate angularly while remaining radially fixed. This integration eliminates the need for separate adjustment mechanisms or additional components, achieving fine alignment precision without increasing device complexity.

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

This solution maintains chronometric performance by preventing radial displacement of the hairspring, ensuring precise alignment and reducing deformation-related defects during assembly and operation.

Implementation Method 1

a clamping element, such as screws, intended to press a surface of a bridge against a surface of a fastening element so as to immobilize the fastening element relative to the bridge, in particular by friction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2799937B1Shock-proof bearing for an horological balance
Publication Date: 2020.09.16 ROLEX SA
  • EP2799937B1 patent drawingFigure 1~2
  • EP2799937B1 patent drawingFigure 3~4
  • EP2799937B1 patent drawingFigure 5~6

AI summary

Shock absorber body (11) of an assembled balance wheel (6) of a watch oscillator (8), comprising a portion (11a) for guiding the shock absorber body (1) for mounting it on a bridge (2) and an element (13) for fixing an outer end of a spiral spring (5) of the oscillator.