Elastic Arm Locking Mechanism for Watch Rotating Elements
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Solution Overview
Problem
Existing locking devices for rotary watch members, such as friction springs, are not suitable for all constructions, occupy excessive space, and fail to provide sufficient friction to withstand significant shocks, as they do not generate enough locking torque during impacts.
Innovation Solution
A locking device comprising an elastic arm with a bearing surface and fixing lugs, designed to deform in flexion, generating a significant locking torque while occupying minimal space, allowing the watch member to be movable during normal use and locked during shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a friction spring is used to lock the timepiece organ, then the locking torque is sufficient to withstand shocks, but the device occupies excessive space and is not suitable for all constructions
Solution Approach 1:
The elastic arm is divided into distinct functional segments: fixing lugs for attachment to the support, a deformable intermediate portion for generating elastic force, and a bearing surface for contact with the timepiece organ. This segmentation allows each part to be optimized for its specific function while maintaining overall compactness.
Solution Approach 2:
The elastic arm is configured to deform primarily in the planar dimension rather than requiring three-dimensional space expansion. By designing the arm to extend substantially in a single plane and deform within that plane, the device achieves high locking torque without increasing overall device volume.
2Stability of the object's composition
If the elastic arm is made rigid to provide stable support, then the fixing lugs can be securely attached, but the bearing surface cannot generate sufficient locking torque through deformation
Solution Approach 1:
The elastic arm exhibits different mechanical properties at different locations: the fixing lugs and their attachment regions are designed for rigidity and stability, while the intermediate portion is designed with appropriate elasticity to deform and generate locking torque. This local differentiation of mechanical properties resolves the contradiction between stability and torque generation.
Solution Approach 2:
The elastic arm transitions from a static rigid structure to a dynamic system that can deform elastically under load. The arm is designed to deform within its elastic limit during normal operation, providing both stability when undeformed and sufficient flexibility to generate locking torque when subjected to shock loads.
3Strength
If the elastic arm deforms significantly to generate high locking torque, then the locking force is sufficient for shocks, but the device occupies more space due to the deformation displacement
Solution Approach 1:
The elastic arm is designed with an S-shaped curvature that allows it to deform efficiently within a compact space. The curved geometry enables the arm to generate significant elastic restoring force through small angular deflections, reducing the linear displacement required for deformation while maintaining high locking torque capability.
Solution Approach 2:
The elastic arm is made from material with optimized elastic properties that allow high stress generation within small deformations. By selecting materials with appropriate elastic moduli and strength characteristics, the device achieves high locking torque without requiring large deformation displacements that would increase device volume.
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 device effectively generates a substantial locking torque to withstand major shocks while maintaining the watch member's mobility during normal operation, ensuring reliable function and compact design.
Implementation Method 1
said arm extending substantially in a single plane and being configured to be capable of deforming in flexion so that the fixing lugs can be fixed to the support by generating a stress lower than the elastic limit of the material of said arm
Data Source
Figure 1~3
Figure 4
Figure 5~6
AI summary
The present invention relates to a locking device (1) for a rotating watch element arranged to allow the watch element to be mobile relative to a support when subjected to a predefined actuation torque and to be locked relative to said support when subjected to a predefined locking torque.The locking device (1) comprises at least one elastic arm (2) having at least one bearing surface (4) intended to be in contact with the watchmaking element, and two fixing lugs (6) provided at each end of the arm (2), intended to be made integral with said support, said arm (2) extending substantially in a single plane and being configured to be capable of deforming in bending so that the fixing lugs (6) can be fixed to the support by generating a stress less than the elastic limit of the material of said arm (2) and that the bearing surface (4) of the arm (2) can exert on said watchmaking element an axial force generating a torque on the watchmaking element greater than or equal to the locking torque and less than the actuation torque. The present invention also relates to a watch movement comprising such a locking device and a watchmaking component comprising such a watch movement.