Elastic Damping Sleeve for Watch Stem Stress Reduction
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Solution Overview
Problem
Timepieces with elastic damping supports face high bending stresses on the winding and time-setting stem during impacts and lateral pressure, which can damage the mechanism.
Innovation Solution
A timepiece design featuring a rigid tube integral with the movement and an elastic damping sleeve between the tube and the case wall, allowing the manual control member to move with the movement and reducing bending stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the movement is held by an elastic annular damping support, then the movement is protected against shocks, but the winding and time-setting stem are subjected to high bending stresses during impacts and lateral pressure
Solution Approach 1:
The patent divides the support structure into two distinct functional components: an elastic annular damping support that protects the movement against shocks, and a rigid tube that specifically protects the winding and time-setting stem. This segmentation allows each component to optimize its function without compromising the other, resolving the contradiction between movement protection and stem stress reduction.
Solution Approach 2:
The rigid tube acts as an intermediary element between the elastic damping support and the winding stem. It provides a stable, stress-free pathway for the stem while allowing the elastic support to function independently for movement protection. The tube mediates the interaction between the elastic support and the stem, preventing direct transmission of bending stresses.
2Device complexity
If the manual control member is engaged directly in the case wall, then the structure is simple, but lateral pressure on the crown causes high stresses in the winding mechanism
Solution Approach 1:
The rigid tube serves as an intermediary structure between the case wall and the manual control member. Instead of engaging the stem directly in the case wall, the tube provides a dedicated, stable passage that isolates the winding mechanism from lateral pressures applied to the crown, thereby reducing stresses while adding minimal structural complexity.
Solution Approach 2:
The manual control member is nested within the rigid tube, which itself is positioned within the case structure. This nested arrangement allows the stem to move freely within the tube while the tube provides protective constraints, reducing stress transmission to the winding mechanism while maintaining a compact overall structure.
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 design effectively absorbs shocks and lateral pressures, minimizing stress on the winding and time-setting mechanism while maintaining ease of assembly and disassembly for maintenance.
Implementation Method 1
an elastic damping sleeve interposed between the tube and said wall
Implementation Method 2
This tube is also surrounded by a shock-absorbing elastic sleeve which allows it to move with the movement, relative to the box, during an impact
Data Source
Figure 1~2
Figure 3
AI summary
The timepiece has an elastic damping ring (7) retaining a movement (19) inside a case (1), and a manual control unit (22) traversing a wall i.e. middle wall (2) of the case and connected to the movement, where the unit is provided with a setting and winding rod (23). A rigid tube (25) traverses the wall and is integrated to the movement. The unit is engaged in the rigid tube. An elastic damping sleeve (26) serving as a sealing joint, is interposed between the rigid tube and the wall, where the tube is made of metal. The rigid tube is surrounded by the sleeve.