Oldham-Type Clock Transmission Joint for Silent Parallel Shafts

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Solution Overview

Problem

Existing clockwork mechanisms face challenges in adjusting the layout of display elements after assembly, requiring complete repositioning of modules and compromising assembly precision due to numerous intermediate blanks, and existing transmission joints are not feasible for certain applications or result in operating noise.

Innovation Solution

A transmission joint with a constant velocity type mechanism that connects parallel shafts using an Oldham joint-like design with elastic return systems and friction elements to ensure precise, homokinetic motion transmission, suitable for compact watch movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If modular clock movements with interchangeable modules are used to adjust display layouts, then adaptability is improved, but manufacturing precision deteriorates due to the large number of intermediate blanks required for module production

Engineering Contradiction:
Improvedisplay layout adjustabilityVSAvoidassembly precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The transmission joint is divided into separate modular components (first component with first shaft portion, second component with second shaft portion) that can be independently manufactured and then precisely assembled together, allowing display modules to be repositioned without compromising overall assembly precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transmission joint acts as an intermediary mechanism between the display module and the main movement, enabling precise angular position adjustment of display elements through its adjustable shaft configuration while maintaining accurate motion transmission

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If display modules are repositioned after basic movement assembly, then adaptability is improved, but device complexity increases due to complete repositioning requirements

Engineering Contradiction:
Improvedisplay layout flexibilityVSAvoidrepositioning complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The transmission joint incorporates adjustable and movable components that allow the angular position of display modules to be modified after assembly, providing dynamic reconfiguration capability without requiring complete disassembly or complex repositioning procedures

Inventive Principle:
Principle #15Dynamics

3Speed

If Oldham joint with slides on distinct planes is used for motion transmission, then motion transmission capability is improved, but device complexity increases and feasibility is limited for certain applications

Engineering Contradiction:
Improvemotion transmission capabilityVSAvoidtransmission joint complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The first and second components of the transmission joint are designed to be merged or closely integrated, with the first component containing both the first shaft portion and the first slide, and the second component containing the second shaft portion and the second slide, reducing the number of separate parts while maintaining constant velocity motion transmission capability

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If wire-based spiral transmission is used to connect shafts, then adaptability is improved, but harmful factors increase due to operating noise

Engineering Contradiction:
Improvetransmission flexibilityVSAvoidoperating noise
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The invention replaces the wire-based spiral mechanical transmission system with a direct rigid connection transmission joint consisting of precisely fitted shaft portions and slides, eliminating the flexible wire mechanism that generates operating noise while maintaining transmission flexibility and adaptability

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

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

The solution enables precise and silent transmission of rotational motion between parallel shafts, allowing for adjustable display layouts without reassembly and minimizing angular play, suitable for watch movements.

Implementation Method 1

a first elastic return system (15) arranged to limit or eliminate play between at least one first shaft section (2A) and at least one second shaft section (3A)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a friction element (13, 14) for transmitting motion between the shafts (21, 31)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3425226B1Clock transmission joint
Publication Date: 2025.11.19 ROLEX SA
  • EP3425226B1 patent drawingFigure 1
  • EP3425226B1 patent drawingFigure 2~3
  • EP3425226B1 patent drawingFigure 4~6

AI summary

Transmission joint (100), in particular a watchmaking transmission joint, for the mechanical connection of at least one first part (2A) of a first shaft, at least one shaft rotatable about a first axis (A2), to at least one second part (3A) of a second shaft, at least one shaft rotatable about a second axis (A3), the first and second axes being parallel or substantially parallel, the transmission joint comprising: - at least one first part (2A) of the first shaft (21), - at least one second part (3A) of the second shaft (31), and - at least one first elastic return system (210: 221, 222, 223, 224) arranged so as to limit or eliminate the play between at least one first part (2A) of the first shaft and at least one second part (3A) of the second shaft, the at least one return system mechanically connecting at least one first part (2A) of the first shaft and at least one second part (3A) of second tree.