Watch Stem Securing Mechanism for Easy Disassembly
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Solution Overview
Problem
Conventional watch designs with rotating elements face challenges in disassembling the control member without breaking the stem due to the strong securing method using screws and bonding, making maintenance difficult.
Innovation Solution
A securing part is positioned on the proximal side of the stem, comprising a slit ring and axial locking means, allowing the pinion to be securely positioned and easily disassembled without damaging the stem.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pinion is secured to stem using screws and bonding, then axial and angular positioning is guaranteed, but control member cannot be disassembled during maintenance
Solution Approach 1:
The securing mechanism is divided into two independent parts: a retaining ring that secures the pinion axially to the stem, and a separate locking mechanism that engages with the stem's square cross-section. This segmentation allows the pinion to be removed from the stem during maintenance while preserving the stem's structural integrity, resolving the contradiction between reliable positioning and ease of repair.
2Reliability
If stem end is made square and engaged in pinion hole, then angular positioning is achieved, but stem becomes longer requiring more space
Solution Approach 1:
The square engagement feature is nested within the existing cylindrical stem structure rather than extending the stem length. The retaining ring and locking mechanism are integrated into the stem's diameter rather than requiring additional axial length, thus achieving reliable angular positioning without increasing stem length and compromising space between pinion and movement.
3Reliability
If stem is made longer to accommodate circlip, then axial positioning is achieved, but space between pinion and movement is insufficient
Solution Approach 1:
Instead of solving the axial positioning problem by extending the stem in the axial dimension, the solution transitions to the radial dimension by using a retaining ring that fits around the stem's circumference. This dimensional shift allows effective axial positioning of the pinion without increasing stem length, preserving the necessary space between pinion and movement.
Data Source
AI summary
The invention concerns a timepiece including a case (10) and a crystal (22) together defining a housing (18) for a movement (20), and further including an element that is mobile in rotation (30) actuated by a control member (36) including a stem (42) of longitudinal axis AA, passing radially through said case (10), a crown (44) mounted on a first proximal end of said stem and a pinion (46) fixedly mounted in rotation on a second distal end of said stem (42). The control member (36) is fitted with a part (48) for axially securing said pinion (46) on said stem (42), arranged on the proximal side of said stem (42), said securing part (48) including:a first slit ring (62) mounted so as to be locked axially and radially on a first of the pinion (46)/stem (42) elements, andmeans for axially locking the second of the pinion (46)/stem (42) elements, secured to said slit ring (62).