Watch Display Coupling Mechanism for Precision Indexing
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Solution Overview
Problem
Existing watch movement display mechanisms face challenges in precisely indexing displays relative to a reference frame, particularly due to machining tolerances, which can result in misalignment and affect the aesthetic quality of the watch.
Innovation Solution
A display device for watch movements featuring a coupling mechanism with a transmission wheel that has a degree of mobility relative to the driving and driven wheels, allowing for adjustable indexing and precise alignment of the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a display is integrated into the kinematic chain of a watch movement with a fixed coupling mechanism, then the structure is simple and easy to manufacture, but the indexing precision is insufficient due to machining tolerances
Solution Approach 1:
The coupling mechanism incorporates a mobile support that can rotate around the axis of the driving wheel, allowing the transmission wheel's position to be adjusted dynamically. This dynamic capability enables precise indexing by accommodating machining tolerances while maintaining a relatively simple overall structure.
Solution Approach 2:
The coupling mechanism is divided into separate functional components: a support structure, a transmission wheel, and a locking member. This segmentation allows the mobile support to be adjusted independently to achieve precise indexing, while each component remains simple in design and easy to manufacture.
2Manufacturing precision
If the transmission wheel is fixed in position, then the coupling mechanism is simple to manufacture, but the display alignment is imprecise due to inability to compensate for machining tolerances
Solution Approach 1:
The mobile support is designed to be adjustable before final assembly, allowing the indexing to be optimized in advance. The support can be positioned precisely and then locked, ensuring display alignment precision is achieved before the watch movement is completed.
Solution Approach 2:
The mobile support acts as an intermediary between the driving wheel and the transmission wheel, providing a buffer that absorbs machining tolerances. This intermediary element allows precise display alignment without requiring extremely tight manufacturing tolerances on the individual components.
3Manufacturing precision
If the transmission wheel position is fixed, then the assembly process is simple and quick, but the indexing cannot be adjusted to meet aesthetic quality criteria
Solution Approach 1:
The mobile support provides adjustability during assembly, allowing the transmission wheel position to be optimized for precise indexing. Once positioned correctly, the locking member secures the support, making the adjustment a one-time operation that does not significantly increase assembly time.
Solution Approach 2:
The coupling mechanism provides localized adjustability only where needed (at the transmission wheel position) while maintaining fixed positions elsewhere. This selective adjustability enables precise indexing without requiring complex adjustment mechanisms throughout the entire assembly, thus minimizing impact on assembly time.
Data Source
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Figure 3
AI summary
The invention relates to a display device (10) for a watch movement, characterized in that it comprises: - a display (11) intended to be mounted so as to be mobile relative to a structure (12) of the watch movement and provided with an indexing member (110) relative to said structure (12), and a driven wheel (111) whose rotation causes the display (11) to move; - a drive mechanism (20) comprising a driving wheel (21) intended to rotate the driven wheel (111); - a coupling mechanism (30) comprising a transmission wheel (31) meshing with the driving wheel (21) and the driven wheel (111), said coupling mechanism (30) being configured such that the center of rotation of the transmission wheel (31) has a degree of mobility relative to the driving (21) and driven (111) wheels.