Watch Movement Frequency Setting via Spring Toothed Wheel

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Solution Overview

Problem

Existing watch movement frequency setting devices are complex, requiring numerous parts and resilient components, and can only be set after the watch movement is mounted in the case, with potential for stress on the spring and precision issues.

Innovation Solution

A simplified watch movement frequency setting device that is self-contained within the watch case, using a moving part with a first toothed wheel and a toothing on the spring's outer end part to vary the spring's active length without affecting a previously set guide mark.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complex setting device with multiple resilient components is used to set the resonator frequency, then the frequency can be adjusted, but the device complexity increases and the resilient components may show fatigue over time

Engineering Contradiction:

Improvefrequency setting reliabilityVSAvoidsetting device complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the resilient components (springs and elastic arms) from the frequency setting device. The outer end part of the balance spring is given a toothing that meshes with toothed wheels on the balance cock, allowing frequency adjustment through pure mechanical engagement without elastic deformation, thus removing the reliability issues associated with resilient component fatigue.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical system based on elastic deformation with a direct mechanical engagement system. Instead of using resilient arms and springs to hold and release the balance spring, the patent uses intermeshing toothed wheels that directly engage with the toothing on the balance spring's outer end part, substituting elastic mechanics with rigid mechanical transmission.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If the setting device requires resilient components to be correctly sized, then frequency setting is possible, but manufacturing precision requirements increase

Engineering Contradiction:

Improvefrequency setting easeVSAvoidcomponent sizing precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The invention changes the fundamental parameter of engagement from elastic deformation to rigid mechanical meshing. The toothing on the outer end part of the balance spring engages with toothed wheels through direct mechanical contact, eliminating the need for precisely sizing resilient components and their elastic properties, thereby reducing manufacturing precision requirements while maintaining ease of operation.

Inventive Principle:

Principle #35Parameter changes

3Strength

If the outer end part of the spring is held by adhesive bonding or lateral screw, then the spring is secured, but stress is created on the spring end affecting frequency setting precision

Engineering Contradiction:

Improvespring attachment strengthVSAvoidfrequency setting precision

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The invention removes the adhesive bonding or lateral screw attachment methods that create stress on the spring end. Instead, the outer end part of the balance spring is given a toothing that allows stress-free mechanical engagement with the toothed wheels on the balance cock, eliminating the harmful stress concentration at the spring end while maintaining secure attachment.

Inventive Principle:

Principle #2Taking out (Extraction)

4Adaptability or versatility

If the frequency setting device is mounted on the watch case, then frequency can be set after case assembly, but the device requires additional parts and increases overall complexity

Engineering Contradiction:

Improvefrequency setting timingVSAvoidnumber of parts

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention merges the frequency setting device components with existing watch movement parts. The toothed wheels are integrated into the balance cock, and the toothing is directly formed on the outer end part of the balance spring itself, eliminating the need for separate setting device components mounted on the case and reducing the overall number of parts while maintaining adaptability for frequency adjustment.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250147466A1Watch movement with device for setting the frequency of a mechanical resonator

Publication Date: 2025.05.08 ETA SA MFG HORLOGERE SUISSE

AI summary

The watch movement includes a mechanical resonator with a balance and a spring, a device for setting the oscillation frequency of the mechanical resonator and a device for setting the guide mark on the mechanical resonator. A moving part of the setting device includes a fastener for attaching an outer end part of the spring and a device for defining the active length of the spring. A mechanism for varying the active length of the spring includes a first toothed wheel, carried by the moving part, and a first toothing, arranged along the outer end part of the spring, with which the first toothed wheel meshes. The fastener holds the outer end part by friction such that the first toothed wheel can drive this outer end part via the first toothing and thus vary the active length of the spring.