Chronograph Display Mechanism Friction Spring Nesting
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Solution Overview
Problem
Existing chronograph mechanisms face challenges in achieving precise friction torque adjustment and reduced bulk due to the thickness and dispersion issues of traditional friction springs, which are critical for accurate resetting and correction in high-precision applications.
Innovation Solution
A disengageable display mechanism using a friction coupling with a housing that integrates the friction spring and pinion bearing surface, allowing for a reduced overall height and precise manufacturing of blades using materials like silicon or NiP to minimize torque dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a traditional spring washer friction spring is used, then the overall thickness of the mechanism is reduced, but the friction torque is widely dispersed between different parts
Solution Approach 1:
The friction spring is nested within a housing that is integrated into the board, with the pinion bearing surface also housed within the same structure. This nesting arrangement allows the friction coupling mechanism to be contained within a compact volume while maintaining precise control over the friction torque through the housing geometry and material properties.
Solution Approach 2:
The housing provides a localized structure that concentrates and controls the friction interaction between the friction spring and pinion bearing surface. By confining the friction coupling within the housing, the friction torque is localized and precisely controlled rather than dispersed, while the overall board thickness remains minimized through efficient spatial arrangement.
2Manufacturing precision
If a friction spring positioned above the board with two blades is used, then the friction torque has low dispersion, but the overall thickness of the mechanism is significantly increased
Solution Approach 1:
The friction spring blades and pinion bearing surface are nested within the housing integrated into the board, rather than positioning the friction spring above the board. This nesting eliminates the need for additional thickness while maintaining the precise friction torque control achieved by the blade configuration.
Solution Approach 2:
Instead of increasing thickness in the vertical dimension to achieve low friction torque dispersion, the solution repositions the friction coupling elements within the planar dimension of the board through the housing structure. This dimensional reorganization maintains precise friction control without sacrificing compactness in the thickness direction.
3Reliability
If the friction torque is increased to ensure coupling during impact, then the display mechanism cannot be corrected by user push button
Solution Approach 1:
The friction spring provides dynamic friction coupling that adapts to operational conditions. The elastic blades of the friction spring allow for temporary disengagement during correction operations when lower friction is needed, while maintaining secure coupling during normal operation and impact events. This dynamic behavior resolves the contradiction between high friction for reliability and low friction for ease of operation.
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 achieves a compact design with low friction torque dispersion, enabling precise resetting and correction while maintaining high precision, thus addressing the bulk and precision challenges in chronograph mechanisms.
Implementation Method 1
a friction spring arranged to couple by friction the board and said bearing surface of the pinion
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a disengageable display mechanism (1) using a friction coupling and comprising a display unit (2) having a shaft (4) on which a board (6) and a display element are rigidly mounted, a pinion (10) freely rotatable about said shaft (4) and having a bearing surface (14), and a friction spring (18) arranged to frictionally couple the board (6) and said bearing surface (14) of the pinion (10). The board (6) includes a recess (20) arranged to house said friction spring (18) and the bearing surface (14) of the pinion (10).