Bistable Watch Control Mechanism With Preloaded Flexible Blades
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Solution Overview
Problem
Existing chronograph watch mechanisms are limited by complexity, wear, breakage risk, and inefficient causal links, particularly in coupling and control mechanisms.
Innovation Solution
A watch mechanism with a bistable assembly comprising a pivoting piece, rigid piece, and preloaded flexible blades, where the pivoting piece's rotation causes the assembly to move between stable positions, reducing the risk of breakage and improving operation through a different causal link.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a column wheel or cam-operated mechanism is used for control, then the start, stop and reset functions can be carried out, but the mechanism becomes thick and difficult to manufacture
Solution Approach 1:
The patent extracts the essential control function from the traditional column wheel structure by using a single-layer part that can rotate and provide bistable positions. This eliminates the need for thick multi-layer column wheels while maintaining the start, stop and reset functions through a simplified rotational mechanism with flexible blades.
Solution Approach 2:
The control mechanism is segmented into a single-layer rotating part with multiple flexible blades (first and second flexible blades) that can independently provide bistable positions. This segmentation allows each component to be optimized for its specific function while reducing overall mechanism thickness and manufacturing complexity.
2Device complexity
If flexible blades are used to connect parts, then the mechanism can be thinner and easier to manufacture, but the flexible blades are subject to wear and breakage
Solution Approach 1:
The patent applies preliminary action by preloading the flexible blades through offset mechanical pivots before the mechanism operates. This preloading creates a bistable configuration where the flexible blades are already under controlled stress, allowing them to reliably maintain their positions while reducing sudden breakage risks during operation.
Solution Approach 2:
The patent changes the parameter of the flexible blades by introducing offset mechanical pivots that alter the stress distribution and preloading characteristics. This parameter change transforms the flexible blades from simple connecting elements to pre-stressed bistable components, improving their reliability while maintaining the thin-profile advantage.
3Device complexity
If a single-layer rotating part is used instead of traditional column wheels, then the mechanism is thinner, but it cannot be reset to zero
Solution Approach 1:
The single-layer rotating part is designed with multi-functionality, serving both as the control mechanism for start/stop/reset functions and as the resettable component. The bistable positions provided by the flexible blades enable the mechanism to not only control the chronograph functions but also to be reset to zero through the same rotational motion, eliminating the need for separate reset mechanisms.
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 mechanism reduces parts and wear, lowers breakage risk, and enhances operational efficiency by utilizing a rotation-based causal link instead of flexible blade bending, enabling functions like coupling and reset.
Implementation Method 1
a first flexible blade (5A) connecting the rigid piece (1) to the pivoting piece (3)... which preloads the first flexible blade (5A) and makes the assembly formed by the rigid piece (1) and the first flexible blade (5A) bistable
Data Source
AI summary
The present disclosure concerns a watch mechanism having, in a main plane: an actuating device, a pivoting piece arranged to pivot under the action of the actuating device around an axis perpendicular to the main plane, a rigid piece, a first flexible blade connecting the rigid piece to the pivoting piece, a mechanical pivot having a main axis offset in the main plane from the axis of rotation of at least one of the pivoting piece and the rigid piece, the pivoting piece being mounted on said mechanical pivot, which preloads the first flexible blade and makes the assembly formed by the rigid piece and the first flexible blade bistable, so that the rotating pivoting piece causes the bistable assembly to move in the main plane, from a first stable position, to a second stable position.