Escapement Mechanism Angular Plane Motion

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Solution Overview

Problem

Mechanical escapements in clock movements have low efficiency due to inertia, friction, and dead strokes, resulting in only about 30% of energy being transmitted to the regulating organ, which affects precision and chronometry.

Innovation Solution

The escapement mechanism features an impulse anchor and adjustment member controlled by control members on the balance wheel axis, cooperating with the escapement wheel set, and moving in planes forming an angle, eliminating dead strokes and reducing inertia by ensuring the entire angular stroke of the impulse member is active.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional Swiss lever escapement is used, then the regulating organ receives energy pulses, but only about 30% of the energy is transmitted due to inertia, friction, and dead strokes

Engineering Contradiction:
Improveenergy transmission efficiencyVSAvoidescapement mechanism structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The escapement mechanism is divided into separate functional components: an impulse member for energy transmission, a control member for regulation, and a locking member for energy storage. This segmentation allows each component to be optimized for its specific function, reducing overall energy loss while maintaining structural complexity at an acceptable level.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The impulse member is designed to move in two different planes: a first plane for the impulse stroke (energy transmission) and a second plane for the reset stroke (repositioning). This dimensional change eliminates dead strokes by ensuring that motion always occurs in the optimal plane for energy transmission, thereby improving energy efficiency without significantly increasing device complexity.

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

2Power

If the impulse member has inertia to maintain force during impulse, then energy transmission is possible, but the inertia causes energy loss and reduces efficiency

Engineering Contradiction:
Improveimpulse forceVSAvoidenergy loss due to inertia
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The escapement mechanism uses periodic action by releasing stored energy in controlled pulses rather than continuous transmission. The locking member stores energy periodically, and the impulse member delivers it in discrete impulses synchronized with the balance wheel's oscillation, minimizing energy loss while maintaining sufficient impulse force.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The locking member performs preliminary action by storing energy in advance during the non-impulse phase. This allows the impulse member to receive pre-charged energy without needing excessive inertia, as the energy is prepared beforehand and transferred efficiently during the impulse stroke.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If dead strokes are present in the impulse member motion, then the mechanism can reset, but the non-active portions of the stroke represent energy loss and reduced precision

Engineering Contradiction:
Improvereset capabilityVSAvoidenergy loss in dead strokes
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The impulse member transitions between two planes: the first plane for active impulse transmission and the second plane for reset motion. By changing planes, the reset stroke does not interfere with the impulse stroke, eliminating dead strokes and ensuring all motion contributes to energy transmission or precise positioning.

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

Solution Approach 2:

The control member acts as an intermediary between the balance wheel and the impulse member. It coordinates the timing and positioning of the impulse member's motion, ensuring that reset actions occur at optimal moments and that the impulse member is precisely positioned for each impulse, thereby eliminating wasted motion.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Force

If friction is present in the escapement mechanism, then mechanical contact for energy transfer is possible, but friction causes energy loss and reduces chronometry precision

Engineering Contradiction:
Improvemechanical contact forceVSAvoidenergy loss due to friction
Core Design Contradiction:
ForceVSLoss of energy

Solution Approach 1:

The patent replaces traditional high-friction mechanical contact with a magnetic field-based interaction between the impulse member and the escape wheel. This substitution eliminates sliding friction while maintaining the necessary force for energy transfer, significantly reducing energy loss and improving chronometry precision.

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

This design significantly improves the efficiency and precision of the escapement mechanism by ensuring all energy from the auxiliary spring is utilized, eliminating dead strokes and maintaining constant energy transmission, thereby enhancing the overall performance and accuracy of the timepiece movement.

Implementation Method 1

a constant-force device (10) comprising an auxiliary spring (11), which itself transmits pulses of constant energy to the regulating device

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

an escapement mechanism comprising an impulse anchor (8) and at least one adjustment member (9, 14)

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2506092B1Escapement mechanism, in particular for a clock movement
Publication Date: 2020.01.08 CARTIER INTERNATIONAL AG
  • EP2506092B1 patent drawingFigure 1
  • EP2506092B1 patent drawingFigure 2
  • EP2506092B1 patent drawingFigure 2a~3a

AI summary

The movement has an escapement mechanism including an impulse lever (8) and a lock pin (9). The lever and the pin are controlled by a control unit e.g. upper cam (6-1), supported on an axle (2) of a hairspring. The lever and the pin cooperate with an escapement mobile (1). The lever and the pin are moved in two different planes forming an angle between a position in which the lever and the pin cooperate with the escapement mobile and another position in which the lever and the pin do not cooperate with the escapement mobile.