Flexible Balance Bridge for Automated Escapement Assembly

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Solution Overview

Problem

The challenge in watchmaking is the difficulty in automating the mounting of balance wheel-balance bridge assemblies onto watch movements, particularly due to the complexity of controlling vertical motion and the need for additional adjustment components, which increases costs and assembly operations.

Innovation Solution

A removable escapement holder assembly with a flexible balance bridge that allows for irreversible adjustment and automated assembly on one side, featuring spacers and positioning means to facilitate precise alignment and adjustment of the balance wheel, enabling assembly in one direction only.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional balance wheel-balance bridge assemblies are mounted on watch movements, then the balance wheel can be secured to the movement, but the vertical motion control becomes complex and requires additional adjustment components

Engineering Contradiction:
Improvebalance wheel securingVSAvoidvertical motion control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The balance bridge is designed with a flexible upper surface that can bend elastically to accommodate the balance wheel in different positions. This flexible surface replaces complex mechanical adjustment components by using material flexibility to control and adjust the vertical motion of the balance wheel, thereby reducing device complexity while maintaining reliable securing.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention changes the physical parameter of the balance bridge from rigid to flexible by selecting materials or structures with appropriate elastic properties. This parameter change allows the bridge to deform under load, enabling automatic adjustment of the balance wheel position without additional adjustment components, thus resolving the contradiction between reliable securing and control complexity.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If additional adjustment components such as screws, nuts, or springs are added to adjust balance swing, then the balance wheel swing can be adjusted, but the number of components and assembly operations increases

Engineering Contradiction:
Improvebalance swing adjustmentVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the need for separate adjustment components (screws, nuts, springs) by integrating the adjustment function directly into the balance bridge structure. The flexible upper surface of the balance bridge itself provides the adjustment capability, removing unnecessary components and simplifying the overall device while maintaining ease of operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the functions of the balance bridge and the adjustment mechanism into a single integrated component. The flexible upper surface of the balance bridge simultaneously serves as both the mounting surface and the adjustment mechanism, eliminating the need for separate adjustment components and reducing the total number of parts while maintaining adjustability.

Inventive Principle:
Principle #5Merging (Combining)

3Extent of automation

If the balance wheel-balance bridge assembly is designed for automated mounting, then assembly can be automated, but the balance wheel remains suspended through the hairspring complicating handling

Engineering Contradiction:
Improveassembly automationVSAvoidhandling difficulty
Core Design Contradiction:
Extent of automationVSEase of operation

Solution Approach 1:

The invention applies preliminary action by pre-positioning the balance wheel onto the flexible balance bridge before the final assembly step. The flexible bridge holds the balance wheel in a stable, predetermined position that facilitates automated handling and mounting, eliminating the suspension issue that complicates handling during automated assembly processes.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If modular sub-assemblies are used in watchmaking, then production efficiency can be improved, but pre-manufacturing adjustments are required to avoid re-adjustment after integration

Engineering Contradiction:
Improveproduction efficiencyVSAvoidadjustment precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention applies self-service by designing the balance bridge with inherent flexibility that enables it to self-adjust to the correct position when the balance wheel is mounted. This self-adjusting capability eliminates the need for complex pre-manufacturing adjustments, allowing modular sub-assemblies to be produced without precise pre-adjustment while maintaining manufacturing precision after integration.

Inventive Principle:
Principle #25Self-service

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 enables efficient, automated, and cost-effective integration of the escapement holder module into watch movements, ensuring precise adjustment of the balance wheel swing without additional parts, thus reducing assembly complexity and costs.

Implementation Method 1

the upper surface of said bridge of balance being more flexible in bending than said lower surface of said escapement bridge, so as to allow mobility, under the action of a force with a normal component applied to said upper surface, of said first complementary surface with respect to said first bearing surface

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2565730B1Clock escapement holder
Publication Date: 2017.11.01 ETA SA MFG HORLOGERE SUISSE
  • EP2565730B1 patent drawingFigure 1~2
  • EP2565730B1 patent drawingFigure 3~4
  • EP2565730B1 patent drawingFigure 5~7

AI summary

escapement assembly (1) comprising a balance wheel (3) with plate (4), and a balance spring (5), and an escape wheel (6) controlled by an anchor (7) cooperating with said plate (4).An escape bridge (10) comprises, on either side of a lower surface (11) with bearings, a first (20) and a second (21) spacers comprising respectively a first (22) and a second (23) bearing surfaces for receiving a first (24) and a second (25) complementary surfaces of a balance bridge (30) on either side of an upper surface (11A) of the latter with bearings, and said upper surface (11A) is more flexible in bending than said lower surface (11) so as to allow a mobility, under a normal force applied to said upper surface (11A), of said first complementary surface (24) relative to said first bearing surface (22) when said second complementary surface (25) is blocked in position on said second bearing surface (23).