Superposed Tooth Stages Drive Dual Date Rings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing date mechanisms in timepieces with superimposed date rings are complex and costly due to their three-dimensional structure, leading to a thick and expensive ring that affects the overall size and readability of the date display, especially in small-format wristwatches.
Innovation Solution
A date mechanism comprising two superimposed date rings with a control wheel having superposed stages of teeth, where each stage has portions with adjacent teeth and portions devoid of teeth, allowing simultaneous driving of the rings during rotation, reducing the complexity and thickness of the rings, enabling a compact and cost-effective design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single date ring with 31 sectors is used, then the structure is simple, but the date display field is too small for sufficient readability in small-format wristwatches
Solution Approach 1:
The date display mechanism is segmented into two separate date rings (first date ring with markings 1-16 and second date ring with markings 17-31) that rotate independently. Each ring has 16 sectors instead of 31, allowing larger marking size while maintaining the 31-day cycle through coordinated rotation of both rings.
2Measurement precision
If two separate date rings are used to increase display size, then the date display readability is improved, but the mechanism complexity increases
Solution Approach 1:
The control wheel merges two functions into a single component: it controls both the first date ring (markings 1-16) and the second date ring (markings 17-31) through its two superimposed tooth stages. The first tooth stage engages with the first date ring while the second tooth stage engages with the second date ring, allowing coordinated rotation of both rings from a single driving mechanism.
3Ease of manufacture
If traditional molding plastic material is used for the rings, then the manufacturing process is established, but the ring thickness increases affecting the overall size of the movement
Solution Approach 1:
The date rings are manufactured from thin metal sheets instead of molded plastic material. This material parameter change enables significantly reduced ring thickness while maintaining structural integrity and precision. The metal sheet construction allows the rings to be much thinner than previously achievable with plastic molding processes.
4Length of stationary object
If thin metal sheets are used for the rings, then the ring thickness is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The control wheel's dual tooth stages are designed to automatically ensure proper engagement with both date rings. The first tooth stage engages with the first date ring while the second tooth stage engages with the second date ring, creating a self-aligning mechanism that compensates for minor variations in tooth positioning. This self-service engagement mechanism reduces the stringency of manufacturing precision requirements for the thin metal sheet rings.
Data Source
Figure 1~3
Figure 4
Figure 5
AI summary
The mechanism (1) has a control wheel (4) provided with superposed toothing stages, where each toothing stage includes a toothed portion and a tooth-free portion. The tooth-free portion of one of the stages is arranged vertical to a toothed portion of the other stage, where teeth of the former stage are superposed on teeth of the latter stage. The teeth of the toothing stages of the control wheel respectively drive flat top and bottom date rings. An independent claim is also included for a watch including a mechanism covering plate fixed to a bottom plate.