Watch Chronograph Movement Single Cam Brake Reset Mechanism
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Solution Overview
Problem
Chronograph movements require numerous parts and complex assembly, making them bulky and difficult to manufacture efficiently.
Innovation Solution
Integration of a single cam that serves both as a brake mechanism and reset mechanism, positioned in the same layer, allowing for the same cam to control the indicator's starting, stopping, and resetting, thereby reducing the number of components and facilitating a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate brake mechanism and reset mechanism are used, then reliable control of indicator position is achieved, but device complexity and number of parts increase
Solution Approach 1:
The brake mechanism and reset mechanism are merged into a single integrated mechanism that shares common components. The cam structure serves dual purposes: its outer periphery interacts with the brake mechanism for stopping the indicator, while its inner recess engages with the reset mechanism for resetting the indicator. This merging reduces the number of separate parts while maintaining the reliability of both braking and resetting functions.
Solution Approach 2:
The cam is designed as a multi-functional element that simultaneously serves as both a brake cam and a reset cam. The same cam structure provides two distinct interaction surfaces: the outer periphery for brake engagement and the inner recess for reset engagement. This universality allows a single component to perform multiple functions that traditionally required separate mechanisms.
2Manufacturing precision
If multiple separate mechanisms are used for brake and reset functions, then precise control is achieved, but assembly complexity increases
Solution Approach 1:
By combining the brake and reset mechanisms into a single integrated structure with a unified cam, the assembly process is simplified. Instead of assembling and aligning multiple separate mechanisms, the integrated design requires fewer assembly steps and less precise alignment between separate components, while the cam's geometry ensures precise control through its designed interaction surfaces.
3Reliability
If traditional separate mechanisms are used, then functional reliability is maintained, but movement thickness increases
Solution Approach 1:
The reset mechanism is nested within the cam structure, specifically utilizing the inner recess of the cam for engagement. This nesting arrangement allows the reset mechanism to occupy space within the existing cam volume rather than requiring separate external space, thereby reducing the overall thickness of the movement while maintaining both brake and reset functions.
Data Source
Figure 1~2A
Figure 2B~2D
Figure 2E~3B
AI summary
The invention relates to a movement for a watch, which movement comprises a rotatable indicator (2-4; 6,7), such as an indicator comprising a chronograph seconds hand (2-4) or minute counter (6,7), the indicator in turn comprising a cam (2; 6) and a brake mechanism (20; 11) movable between at least a first posi-tion wherein the brake mechanism (20; 11) engages the in-dicator (2-4; 6,7) to maintain the indicator in a rota-tional position and a second position wherein the brake mechanism (20; 11) releases the indicator. The movement further comprises a reset mechanism (30) for returning the cam (2; 6) and thus the indicator (2-4; 6,7) to a default position, such as a zero or start position, wherein the cam (2; 6), at least part of the brake mechanism (20), and at least part of the reset mechanism (30) are positioned in the same layer.