Dial Foot Retaining Key With Progressive Collar Engagement
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Solution Overview
Problem
Existing dial fixing solutions in watches cause material tearing and deformation, mechanical play, and significant mechanical stresses due to the large cutting edge of the collar, leading to potential damage and instability in the watch movement.
Innovation Solution
A key with a cylindrical head and a collar of truncated cone shape, arranged eccentrically, minimizes material deformation by progressively penetrating the dial foot with minimal radial projection, allowing precise control of rotation for optimal fixing and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the collar uses a large cutting edge to penetrate the dial foot, then the dial can be securely fixed, but material is torn from the foot creating burrs and chips that can block or damage moving components
Solution Approach 1:
The collar's radial projection varies locally around the periphery of the head, being minimal at certain locations and maximum at others. This local variation in geometry allows the collar to engage the dial foot progressively rather than all at once, preventing material tearing while maintaining secure fixation.
Solution Approach 2:
The collar transitions from a static, uniform cutting edge to a dynamic, variable projection that engages the dial foot progressively during rotation. The varying radial projection creates a controlled deformation process that prevents sudden material failure and chip formation.
2Reliability
If the collar uses a large cutting edge to penetrate the dial foot, then the dial can be securely fixed, but mechanical stresses on the foot and key become significant
Solution Approach 1:
The variable radial projection of the collar distributes the cutting action locally rather than concentrating it across a large edge. This reduces peak mechanical stresses on both the dial foot and the key during the fixation process.
3Reliability
If the collar penetrates the dial foot deeply, then the dial can be securely fixed, but mechanical play occurs between the foot and key when reattaching deformed feet
Solution Approach 1:
The collar's radial projection parameter varies around the periphery, creating a controlled engagement that deforms the foot minimally while maintaining secure fixation. This reduces the mechanical play that occurs when reattaching deformed feet.
Data Source
Figure 1~5
AI summary
The invention relates to a key (10) for retaining a dial foot (20), said key comprising a cylindrical head (11) arranged at the end of a rod (12), the head (11) and the rod (12) being coaxial, the head (11) comprising a flat (13) and a collar (14) extending over a portion of its periphery in an angular sector defined around the longitudinal axis of the rod (12), on either side of the flat (13), the key being characterized in that said collar (14) comprises a right section of frustoconical shape and forms, with respect to the periphery of the head (11) a minimal radial projection, substantially zero, at the ends of this angular sector and forms a maximum radial projection between these ends.