Thermal Shape-Memory Micromechanics for Precise Watch Setting
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Solution Overview
Problem
Existing micromechanical devices for horology require actuation from outside the case, complicating the movement and affecting the timepiece's water resistance and precision, with existing actuation methods failing to provide sufficient setting precision.
Innovation Solution
A thermally-actuated micromechanical device with a shape memory material support that moves between locked and coupled positions based on temperature changes, allowing remote actuation without opening the case, using a lever to connect two mobiles for precise setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a magnetic actuator is used to actuate the micromechanical device from outside the case, then the device can be actuated remotely, but the setting precision is insufficient
Solution Approach 1:
The patent replaces magnetic actuation with thermal actuation using a shape memory alloy support. The thermal field substitutes the magnetic field, enabling precise mechanical engagement through temperature-controlled deformation of the support structure, thereby achieving both remote actuation and high setting precision.
Solution Approach 2:
The patent changes the actuation parameter from magnetic field strength to temperature. By controlling the temperature of the shape memory alloy support, the system achieves precise control over the engagement and disengagement of the micromechanical device, overcoming the precision limitations of magnetic actuation.
2Ease of operation
If additional mechanical components are added to allow access to the horology module for actuation, then the module can be actuated from outside the case, but the movement becomes more complex
Solution Approach 1:
The patent extracts the actuation function from the mechanical domain and transfers it to the thermal domain. The shape memory alloy support performs the actuation function through thermal deformation, eliminating the need for additional mechanical transmission components, crowns, or stems that would otherwise be required to access and actuate the horology module from outside the case.
Solution Approach 2:
The shape memory alloy support acts as an intermediary between the external thermal actuation source and the internal micromechanical device. It translates external temperature changes into precise mechanical movements for engagement and disengagement, serving as a compact mediator that eliminates complex mechanical access mechanisms.
3Ease of operation
If the case is opened to access the timepiece module for actuation, then the module can be directly accessed, but the pressure inside the case changes which negatively affects the rate of the regulating organ
Solution Approach 1:
The patent replaces mechanical access (opening the case) with thermal actuation through the case. The shape memory alloy support enables the micromechanical device to be actuated through the intact case structure using temperature changes, maintaining the case's pressure seal and preventing disruptions to the regulating organ's rate while still enabling module actuation.
4Ease of operation
If a thermal actuator is used to actuate the micromechanical device from outside the case, then the device can be actuated remotely without opening the case, but the case structure must accommodate thermal actuation
Solution Approach 1:
The shape memory alloy support serves multiple functions: it acts as both the actuator and the structural element that transmits thermal deformation to the micromechanical device. This multi-functionality eliminates the need for separate thermal actuation mechanisms integrated into the case, as the support itself performs both actuation and structural roles, maintaining case simplicity.
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 precise setting of horology mechanisms from outside the case, simplifying the movement and maintaining water resistance, while eliminating the need for additional mechanical components and ensuring accurate actuation.
Implementation Method 1
the support comprises at least in part, preferably completely, a memory material that is thermally distortable when it exceeds a threshold temperature
Implementation Method 2
the lever comprises a curved portion, the lever straightening to move the second mobile from the locked position to the coupled position
Data Source
AI summary
A thermally-actuated micromechanical device (1), in particular for a horology movement, the micromechanical device (1) including a first mechanically-actuatable mobile (3) and a second mechanically-actuatable mobile (4), the second mobile (4) being translationally mobile relative to the first mobile (3) between a coupled position, in which the first mobile (3) mechanically engages with the second mobile (4) to actuate it, and a locked position, in which the second mobile (4) cannot engage mechanically with the first mobile (3), the micromechanical device (1) including a support (5) on which the second mobile (4) is mounted, wherein the support (5) is thermally distortable to move the second mobile (4) from the locked position to the coupled position and/or inversely.