Wristwatch Clasp Length Adjustment via Nested Longitudinal Mechanism
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Solution Overview
Problem
Conventional wristwatch clasps face challenges in fine adjustment, aesthetics, and weight reduction, with existing mechanisms often being bulky, visible, and requiring external actuation, which can lead to accidental opening and increased thickness.
Innovation Solution
A folding clasp design with integrated length adjustment, where the movable part is housed within a central structure, allowing longitudinal movement without external pushers or sliders, and utilizing non-metallic materials for weight reduction and aesthetic integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fine adjustment mechanism with movable part and locking device is added to the clasp, then the bracelet length can be precisely adjusted, but the clasp thickness increases
Solution Approach 1:
The movable part is housed within a central structure of the clasp, with the adjustment mechanism nested inside the clasp body rather than extending externally. The movable part moves longitudinally within the central structure while remaining contained within the overall clasp envelope, preventing thickness increase.
Solution Approach 2:
The adjustment mechanism operates in the longitudinal direction of the bracelet rather than radially outward from the clasp face. By moving the movable part along the length of the bracelet, the mechanism achieves adjustment functionality without increasing the radial thickness of the clasp.
2Adaptability or versatility
If a length adjustment device with external pushers or sliders is added, then the bracelet length can be adjusted, but the clasp becomes more visible and less aesthetic
Solution Approach 1:
The adjustment mechanism is extracted from external visible surfaces and relocated to the interior of the clasp structure. The movable part and locking device are positioned within the central structure, hidden from external view, while still providing full adjustment functionality through longitudinal movement along the bracelet length.
Solution Approach 2:
The length adjustment device is merged with the central structure of the clasp, integrating the adjustment mechanism into the existing clasp architecture rather than adding separate external components. This integration allows the adjustment mechanism to share space with the clasp structure and remain aesthetically pleasing.
3Strength
If traditional metal materials are used for the clasp, then the structure is strong and durable, but the weight increases
Solution Approach 1:
The clasp is constructed using composite materials, combining metal components for structural elements requiring strength with non-metallic materials for components where full metal strength is not critical. This composite approach reduces overall weight while maintaining necessary structural integrity for the folding mechanism and locking device.
Solution Approach 2:
Different materials are applied to different parts of the clasp based on local requirements. Metal is used for high-stress areas such as the hinge and locking mechanism, while non-metallic materials are used for the central structure and housing components, optimizing the weight-strength balance locally across the clasp structure.
Data Source
Figure 1~3B
Figure 4~5
Figure 6A~8
AI summary
The invention relates to a clasp (10) for bracelets, particularly for wristwatches, comprising a fine adjustment device (4) for the bracelet length. The adjustment device is preferably arranged on a central support structure (6) so as to emerge from a free end (8) thereof. A locking mechanism (3) is arranged such that the activation of a manipulator (9) causes the movement of a part of the fine adjustment device, thereby unlocking a movable part and allowing the adjustment of the usable bracelet length.