Display Wheel Friction Mechanism for Stable Torque Assembly
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Solution Overview
Problem
Existing friction systems in watchmaking, such as lanterns and friction wheels, face challenges with difficult control and stability of friction torque over time, as well as complex assembly and disassembly processes.
Innovation Solution
A timepiece display wheel set with elastic blades that adjust frictionally with a shaft, utilizing a flange and elastic monobloc structure to ensure consistent friction torque and easy assembly/disassembly through a tool-operated mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional friction systems (lanterns and friction wheels) are used, then friction drive is achieved, but friction torque control is difficult and stability is poor over time
Solution Approach 1:
The patent applies elasticity to create a dynamic friction system where elastic blades can deflect and adapt to the shaft. The elastic blades are designed with specific dimensions and materials to provide controlled friction torque that can be adjusted by modifying blade thickness, length, or material properties, enabling both stable and controllable friction drive
Solution Approach 2:
The invention changes the physical parameters of the friction system by using elastic blades with variable thickness and dimensions. The friction torque can be controlled by adjusting blade parameters such as thickness at different sections, length, and material properties, allowing precise control while maintaining stability over time
2Ease of manufacture
If traditional friction systems are used, then friction drive is achieved, but assembly and disassembly are difficult
Solution Approach 1:
The display wheel is segmented into modular components: a flange, multiple elastic blades, and indexing elements. This segmentation allows the friction system to be easily assembled by attaching blades to the flange and indexed to the shaft, and disassembled by reversing the process, greatly simplifying maintenance and adjustment
Solution Approach 2:
The elastic blades are designed to be self-retaining through their elastic properties and indexing mechanisms. Once assembled, the blades automatically maintain their position and friction contact with the shaft without requiring additional locking mechanisms, making the system self-servicing and easy to maintain
3Reliability
If elastic blades are used for friction cooperation, then friction torque stability is improved, but plastic deformation may occur during assembly
Solution Approach 1:
The elastic blades are designed with predetermined deflection capabilities and stress distribution characteristics. The blade geometry and material selection are optimized beforehand to absorb assembly stresses elastically without exceeding the material's yield point, preventing plastic deformation while ensuring consistent friction torque
Solution Approach 2:
The elastic blades have non-uniform thickness distribution along their length, with varying local properties optimized for different functions: thicker at the base for structural strength, thinner at the friction contact area for proper elastic deflection and friction control, preventing stress concentration and plastic deformation
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 provides a stable and easily controllable friction torque, ensuring long-term stability and simplifying the assembly process without causing plastic deformation.
Implementation Method 1
at least one elastic blade 4 tending to be returned to a rest position close to a display axis DA, for its friction-driven cooperation with a shaft 2
Implementation Method 2
at least one elastic blade 4 tending to be returned to a rest position close to a display axis DA
Data Source
Figure 1~3
Figure 4~6
Figure 7~9
AI summary
A clockwork display mobile (1) comprising at least one elastic blade (4) returned towards a display axis (DA), for its cooperation by friction with a shaft (2) of a drive mobile (3) of a movement (100) or mechanism, around said axis (DA), this mobile (1) comprises a flange (5) having, opposite each elastic blade (4), an opening (6) for the insertion and guidance of a manual or robotic tool, to allow the separation by this tool of the elastic blade (4) from its rest position, and the insertion of the mobile (1) onto a shaft (2) when the elastic blade (4) is sufficiently separated to ensure its passage, and to ensure a friction of constant value of all the elastic blades (4) on this shaft (2) when they are in frictional cooperation with this shaft (2) and when the tool is no longer in contact with the elastic blades (4).