Clock Motor Module Clip Bridge for Gear Alignment and Rework

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Solution Overview

Problem

Existing motor module assembly methods in mechanical watchmaking are inflexible, making disassembly difficult and prone to mechanical damage, and do not ensure proper gear train alignment and clamping force.

Innovation Solution

The use of clipping mechanisms on the gear train bridge, made of non-magnetic material with high elasticity, allows for easy disassembly and reassembly without damage, ensuring sufficient clamping force and gear alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If heat-riveting process is applied to secure gear train to plate, then initial support and alignment is achieved, but disassembly becomes impossible without mechanical damage

Engineering Contradiction:
Improveattachment strengthVSAvoiddisassembly capability
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The clipping mechanism is divided into separate components: a clipping element on the gear train bridge and a corresponding receptacle on the plate. This segmentation allows the connection to be divided into attachable and detachable parts, enabling disassembly without damage while maintaining strong attachment during operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clipping mechanism transforms the static, permanent heat-riveted connection into a dynamic, reversible connection. The clipping element can be engaged and disengaged from the receptacle, allowing the system to transition between assembled and disassembled states while maintaining structural integrity in both states.

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If spacer and screw fastening method is used between gear bridge and mainplate, then assembly is simplified, but disassembly is difficult and time-consuming

Engineering Contradiction:
Improveassembly simplicityVSAvoiddisassembly time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The connection is segmented into a clipping element and receptacle that can be independently engaged and disengaged. This eliminates the need for multiple screws and spacers, allowing rapid single-step assembly and disassembly while maintaining secure connection during operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The traditional mechanical fastening system using screws, spacers, and multiple components is replaced with a simplified clipping mechanism. This substitution reduces assembly complexity and enables quick disassembly without requiring specialized tools or multiple steps.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If tenons are used to engage gear train on pivots, then initial alignment and centering is achieved, but clamping force is insufficient allowing bridge to slip

Engineering Contradiction:
Improvegear alignmentVSAvoidclamping force
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The alignment and clamping functions are merged into a single clipping mechanism. The clipping element simultaneously provides precise alignment through its geometric fit with the receptacle and sufficient clamping force through its elastic engagement, eliminating the need for separate tenons and additional fastening steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The clipping mechanism utilizes materials with appropriate mechanical properties combining rigidity for precise alignment and elasticity for sufficient clamping force. The gear train bridge is made of non-magnetic material with high modulus of elasticity, creating a composite structure that achieves both alignment precision and clamping strength.

Inventive Principle:
Principle #40Composite materials

4Ease of operation

If gear train bridge is pressed onto plate with insufficient clamping force, then assembly is simple, but gear play cannot be guaranteed and pivots may become disengaged

Engineering Contradiction:
Improveassembly easeVSAvoidgear play control
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The clamping force parameter is optimized through the elastic properties of the clipping mechanism and the high modulus of elasticity material. This ensures sufficient force is applied to maintain proper gear engagement and prevent pivot disengagement, while the simple clipping action maintains ease of assembly.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The clipping mechanism employs curved or inclined surfaces that provide progressive engagement and optimal contact distribution. This geometric design ensures uniform clamping force across the gear train bridge-plate interface, maintaining reliability while preserving assembly simplicity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

Enables easy disassembly and reassembly of motor module components without damage, maintaining gear alignment and clamping force, and eliminates the need for heat-riveting, saving time and reducing mechanical risk.

Implementation Method 1

The gear train bridge is made of a non-magnetic material. Such a non-magnetic material preferably has a high modulus of elasticity. This ensures optimal clipping of the gear train bridge onto the mainplate and guarantees an optimized clamping force between these two parts.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3923086B1Motor module for a clock movement
Publication Date: 2025.12.17 ETA SA MFG HORLOGERE SUISSE
  • EP3923086B1 patent drawingFigure 1~2
  • EP3923086B1 patent drawingFigure 3~4
  • EP3923086B1 patent drawingFigure 5

AI summary

The invention relates to a motor module (4) for a watch movement (2), the motor module (4) comprising a plate (6) carrying one or more gears (12), and a gear bridge (8) mounted on the plate (6), characterized in that the gear bridge (6) comprises means (18) for clipping the gear bridge (8) onto the plate (6).