Planetary Gear Display Device for Timepiece Assembly Simplification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing analogue display devices for timepieces, such as those using planetary gears, require complex assembly operations due to the conventional mounting of hands on an hour wheel, leading to axial space issues and increased part complexity.
Innovation Solution
A compact analogue display device with a planetary gear drive system where the second display member extends above the dial and pivots on the axis of the planet pinion, reducing parts and assembly complexity, and utilizing a drive arbour coaxial to the main arbour for simplified structure and assembly, with a motor element driving a central pinion and planet pinions, and a pivot connection for stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional mounting of hands on an hour wheel is used, then the display device can be manufactured, but the assembly operations become complex and axial space is increased
Solution Approach 1:
The patent extracts the hour wheel component from the conventional assembly by directly mounting the hour hand on the drive arbour. This eliminates the intermediate hour wheel and its associated mounting operations, simplifying the assembly process while maintaining the 1:2 gear reduction ratio between hour and minute hands through the planetary gear system configuration.
2Reliability
If conventional hour wheel mounting is used, then the display device functions, but axial space requirements increase
Solution Approach 1:
The patent implements nesting by integrating the planetary gear system within the existing axial space of the timepiece movement. The planet pinions are positioned between the drive arbour and the crown wheel, allowing the gear reduction mechanism to be compactly arranged without increasing overall axial thickness, thereby enabling direct mounting of the hour hand on the drive arbour.
3Area of stationary object
If the second display member is arranged above the dial, then radial space is optimized, but axial space problems and complex correction mechanisms arise
Solution Approach 1:
The patent resolves the spatial conflict by changing the dimensional arrangement of the planetary gear system. Instead of arranging components primarily in the axial direction (which would require correction mechanisms), the system is configured to operate in the radial plane, allowing the second display member to extend above the dial without requiring additional axial space or complex correction mechanisms.
Data Source
AI summary
The invention concerns a timepiece (10) including a display device (26) including a first and second display member (38, 40) displaying first and second pieces of information, the value of the second piece of information being linked to the value of the first piece of information by a reduction ratio, wherein the first (38) and the second (40) display members are rotatably mounted in relation to a plate (42) and are driven by a drive device (44) with planetary gears, characterized in that the second display member (40) pivots on the axis of rotation (A2) of a planet pinion (54). The invention also proposes a timepiece (10) fitted with this display device (26) and a method for manufacturing this display device (26).