Shape Memory Alloy Ring for Timepiece Cannon-Pinion
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Solution Overview
Problem
Conventional manual lanterning in clockwork movements is random and lacks precision, leading to inconsistent friction torque and after-sales issues, as it depends heavily on the watchmaker's dexterity and sensitivity, and is not reproducible.
Innovation Solution
A clockwork pavement with a shape memory alloy ring that undergoes pseudoplastic deformation to provide controlled friction torque, allowing for reproducible assembly and fixation of the shank, utilizing thermally or magnetically activated shape memory alloys to achieve precise clamping through localized heating or cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual lanterning is used to pinch the roadway tube, then the shank can be fixed in place, but the clamping force is random and inconsistent depending on the watchmaker's skill
Solution Approach 1:
The shape memory alloy ring automatically adjusts its clamping force on the roadway tube based on temperature changes, eliminating the need for manual adjustment by the watchmaker. The ring self-regulates the friction torque to match the manufacturer's specifications without requiring operator skill or dexterity.
Solution Approach 2:
The invention changes the physical state of the shape memory alloy ring by varying temperature (heating or cooling) to control its clamping force. By transforming the material between austenitic and martensitic phases through temperature control, the system achieves precise and reproducible friction torque values.
2Manufacturing precision
If manual lanterning is performed to adjust friction torque, then the shank fixation can be achieved, but the process lacks reproducibility and precision
Solution Approach 1:
The invention replaces the manual mechanical pinching process with a shape memory alloy-based system that uses thermal or magnetic fields to control clamping. This substitution enables precise control of friction torque through material phase transitions rather than manual mechanical force application.
Solution Approach 2:
The shape memory alloy ring exploits phase transitions between austenitic and martensitic states to control its dimensions and clamping force. By inducing phase transitions through temperature or magnetic field changes, the system achieves precise and reproducible friction torque control that is independent of operator skill.
3Duration of action of stationary object
If the roadway tube is manually pinched during lanterning, then the shank is secured, but the pavement becomes fragile and may require replacement after dismantling
Solution Approach 1:
The shape memory alloy ring is designed as a replaceable component that can be removed and reused. When the pavement becomes worn or damaged, the ring can be taken off the old roadway tube and transferred to a replacement tube, extending the overall service life of the assembly without requiring replacement of the entire mechanism.
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 ensures precise and reproducible control of the clamping force, reducing dependence on operator skill and enabling automated assembly, thus improving the reliability and longevity of clockwork movements.
Implementation Method 1
at least one ring (8) made of shape memory alloy, having a second bore (9) which has, in the free state, a diameter greater than that of the bearing surface (7) when the ring (8) is in a martensitic structure, and a diameter smaller than that of the bearing surface (7) when the ring (8) is in an austenitic structure
Implementation Method 2
a first phase of initial deformation of the ring (8) made of shape memory alloy in a first martensitic state and at a temperature below a first transformation start temperature As, characteristic of the start of the transformation of the martensitic structure into the austenitic structure on heating
Data Source
Figure 1~7
AI summary
A watch case (1) comprising a first bore (2) for receiving a stud (3) having, on either side of a clearance (4), a first (5) and a second (6) bearing surface. Said case (1) is made in two parts and comprises, on the one hand, a body (10) having internally said first bore (2) and externally a bearing surface (7), and on the other hand, a ring (8) made of shape-memory alloy having a second bore (9), and said second bore (9) has, in the free state, a diameter greater than that of said bearing surface (7) when said ring (8) is in a martensitic structure, and a diameter less than that of said bearing surface (7) when said ring (8) is in an austenitic structure.