Monolithic Escapement Locking Device for Wristwatch

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Solution Overview

Problem

The existing watch escapement mechanisms suffer from significant functional play in mobile displacements, leading to performance issues due to difficulties in accurate setting and sensitivity to dimensional variations of constituent parts, requiring tight manufacturing tolerance intervals.

Innovation Solution

A locking device for a toothed wheel with a frame, blocker, and elastic elements, where the elastic elements are connected to the blocker and frame, allowing for improved relative positioning, increased pivoting angle, and adjustable tension/compression, facilitating easier adjustment and manufacturing with broader tolerance intervals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional anchor design with separate elastic elements is used, then the structure allows for some flexibility, but the positioning precision deteriorates due to functional clearances and sensitivity to dimensional variations

Engineering Contradiction:
Improvepositioning precisionVSAvoidassembly complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple separate components (blocker body, elastic elements, and mounting structure) into a single integrated piece. This eliminates the need for separate assembly of these parts, thereby improving positioning precision by removing functional clearances between components while reducing overall assembly complexity through monolithic fabrication.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated piece is designed with distinct functional zones: a blocker body portion, elastic element portions, and mounting portions. This segmentation within a monolithic structure allows each function to be optimized independently during design while maintaining manufacturing precision through single-piece fabrication, avoiding the positioning errors that would arise from assembling separate parts.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If tight manufacturing tolerances are applied to traditional anchor components, then positioning accuracy improves, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvedimensional toleranceVSAvoidfabrication complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By combining all critical components into one integrated piece, the patent eliminates the need for tight tolerances between multiple parts. The monolithic structure ensures precise relative positioning of all functional elements through the fabrication process itself, allowing for more relaxed dimensional tolerances on individual features while maintaining overall positioning accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention changes the fundamental parameter of component configuration from multiple separate parts to a single integrated piece. This parameter change transforms the manufacturing challenge from controlling tight tolerances across multiple components to controlling the geometry of one component, significantly easing manufacturing requirements.

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If elastic elements are connected on the same side of the blocker, then the structure is compact, but the pivoting angle is limited

Engineering Contradiction:
Improvepivoting angleVSAvoidspatial footprint
Core Design Contradiction:
Length of moving objectVSArea of stationary object

Solution Approach 1:

The patent distributes elastic elements to opposite sides of the blocker body, utilizing the spatial dimension more effectively. This dimensional arrangement allows the blocker to pivot through a larger angle by leveraging the leverage provided by elastic elements positioned on both sides, thereby increasing the pivoting angle without significantly increasing the overall spatial footprint of the mechanism.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Reliability

If functional clearances are increased in the escapement mechanism, then ease of assembly improves, but performance deteriorates due to backlash

Engineering Contradiction:
Improveescapement performanceVSAvoidassembly ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

By integrating the blocker and elastic elements into one piece, the patent eliminates functional clearances between these components. The monolithic structure ensures direct, clearance-free transmission of forces and movements, thereby improving escapement performance and eliminating backlash while not complicating the assembly process since the integrated piece is installed as a single unit.

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

The solution minimizes backlash, enhances precision, and increases the performance of the mechanism by allowing for a bistable behavior, reducing energy loss and improving the dynamic behavior of the escapement, while also simplifying the assembly and reducing sensitivity to manufacturing imperfections.

Implementation Method 1

first and second elastic elements, each having one end connected to the lock and the other end connected to the frame; a third elastic element connected to the lock

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2553533B2Device for locking a toothed wheel
Publication Date: 2019.06.19 ROLEX SA
  • EP2553533B2 patent drawingFigure 1
  • EP2553533B2 patent drawingFigure 2
  • EP2553533B2 patent drawingFigure 3

AI summary

The invention relates to an immobilizing device for a toothed wheel suitable for the field of horology where it can be part of a direct- or indirect-impulse escapement, in particular in a wristwatch. This immobilizing device (1, 2, 3, 4, 5, 6) comprises: - a base (7); - an immobilizer (9) comprising two arms (10, 11) each provided with a pallet (14, 15) intended to come into contact with a tooth of the toothed wheel (40); - a first and a second elastic element (12, 13) each having an end connected to the immobilizer (9) and another end connected to the base (7); - a third elastic element (16) connected to the immobilizer (9), and it has the particular feature that it is in one piece or in one piece apart from at least one of the pallets (14, 15). The invention also relates to a timepiece and to a method for assembling such a timepiece.