Watch Locking Device Reducing Friction via Periodic Engagement

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Solution Overview

Problem

Existing blocking devices in watchmaking, such as those described in EP 1658531 and EP 2166419, generate excessive friction due to their complex mechanisms and permanent contact with drive components, which affects the efficiency and reliability of timepiece mechanisms.

Innovation Solution

A blocking device with a mobile frame guided by a flexible guiding device, featuring a drive member and a blocking member that interact with drive and stopping elements to control the rotation of a gear train, minimizing contact and friction by allowing translational movement and using elastic components to compensate for restoring forces, ensuring low friction and precise date indication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If locking devices use complex mechanisms with permanent contact (such as levers, cams, or anchor with fork and pallets), then the locking function is achieved, but friction is excessive and energy is wasted

Engineering Contradiction:
Improvelocking functionVSAvoidfriction
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The locking device uses periodic action by allowing the movable frame to translate only during specific intervals (less than 50% of a rotational revolution) to disengage the blocking member from the stop element. This periodic engagement-disengagement cycle reduces continuous friction contact while maintaining reliable locking function when needed.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention applies dynamics by using a movable frame that can translate along a guided path, transforming the static permanent contact mechanism into a dynamic system where contact is temporary and controlled. The blocking member moves from a stationary blocking position to an engaged position only when the frame translates, reducing continuous friction.

Inventive Principle:
Principle #15Dynamics

2Reliability

If locking devices use permanent contact mechanisms (such as anchor with fork in permanent contact with drive cam), then the locking function is reliable, but the device complexity and friction increase

Engineering Contradiction:
Improvelocking functionVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking device is segmented into distinct functional components: a movable frame with guided translation, a blocking member on a separate axis from the drive member, and a stop element. This segmentation allows each component to perform its function independently with minimal interaction, reducing overall mechanism complexity while maintaining reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The movable frame acts as an intermediary between the drive member and the blocking member. Instead of direct permanent contact between drive and blocking components, the frame mediates the interaction through controlled translation, simplifying the overall mechanism while ensuring reliable locking through the blocking member's engagement with the stop element.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If blocking members are in permanent contact with stop elements, then the locking is secure, but friction and energy consumption increase

Engineering Contradiction:
Improvelocking securityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The blocking member engages with the stop element only periodically during the frame's translation cycle, specifically during the portion of rotation that constitutes less than 50% of a full revolution. This periodic engagement maintains secure locking when required while minimizing energy consumption by eliminating continuous friction contact.

Inventive Principle:
Principle #19Periodic action

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 reduces friction by limiting contact between drive and blocking members to less than 50% of a rotational revolution, ensuring low energy consumption and maintaining the accuracy of the timepiece's primary gear train while enabling instantaneous date display without disturbing the main energy source.

Implementation Method 1

a flexible guiding device (8b) guiding said movable frame (8a) in its movement

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3612897B1Locking device for a timepiece mechanism
Publication Date: 2024.07.24 PATEK PHILIPPE SA
  • EP3612897B1 patent drawingFigure 1
  • EP3612897B1 patent drawingFigure 2~3
  • EP3612897B1 patent drawingFigure 4~5

AI summary

The invention relates to a locking device (8) for a timepiece, comprising first and second movable portions (8a', 8a''; 8s, 8t) kinematically connected to each other, the first movable portion (8a'; 8s) comprising a drive device (8h), and the second movable portion (8a'; 8t) comprising a stop device (8i); a rotary drive member (8f) intended to rotate in a single direction and arranged to cooperate with the drive device (8h) to move the first movable portion (8a'; 8s) and, hence, the second movable portion (8a'; 8t), in alternate opposite directions; and a rotating locking member (8g) intended to be tensioned and arranged to cooperate with the stop device (8i) such that it is locked by the second movable portion (8a''; 8t) and released at predetermined times by the movements of the second movable portion (8a''; 8t). The stop device (8i) is arranged such that the cooperation between the rotating locking member (8g) and the stop device (8i) immobilises the second movable portion (8a''; 8t) and, hence, the first movable portion (8a'; 8s), when the rotary drive member (8f) does not cooperate with the drive device (8h). In normal operation, the rotary drive member (8f) is in contact with the first movable portion (8a'; 8s) only when it cooperates with the drive device (8h), i.e. over less than 60%, preferably less than 50%, preferably less than 40%, preferably less than 30% and preferably less than 20%, of a single rotation of the rotary drive member (8f).