Watch Cam Follower Mechanism for Accurate Sunrise Sunset Display
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Solution Overview
Problem
Existing timepiece mechanisms for displaying sunrise and sunset times on a watch face suffer from reading errors due to the arcuate travel of rakes, require complex cam shape calculations, generate significant friction, and are difficult to assemble, especially near the poles where the cam shape is more marked and the gear ratio needs frequent adjustments.
Innovation Solution
A watch mechanism using follower members guided by elastic means and flexible blades to translate parallel to the cam's movement, allowing the cam to pivot the indicator drive wheel without reading errors and enabling easy replacement of cams without altering the gear ratio, reducing friction and assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a cam mechanism with a rake is used to display sunrise and sunset times, then the information can be displayed on the dial, but reading errors occur due to the arcuate travel of the rake
Solution Approach 1:
The patent introduces a follower member as an intermediary element between the cam and the indicator drive wheel. The follower member converts the arcuate motion of the cam into linear motion, which then drives the indicator wheel through a toothed sector. This intermediary mechanism eliminates reading errors while avoiding complex cam shape calculations.
Solution Approach 2:
The patent replaces the direct cam-rake-indicator mechanical system with a cam-follower-linear motion-indicator system. By substituting the traditional rake mechanism with a follower member that moves linearly along the cam profile, the system achieves accurate reading without requiring complex cam geometry corrections.
2Measurement precision
If the cam shape is corrected for polar locations, then reading accuracy improves, but the gear ratio must be adjusted for different latitudes
Solution Approach 1:
The follower member and toothed sector mechanism serves multiple functions: it accurately tracks the cam profile for any latitude, converts motion without reading errors, and maintains a consistent gear ratio. This universal mechanism works for all latitudes without requiring adjustment, making the device adaptable to different geographical locations.
Solution Approach 2:
The patent uses a dynamic follower member that can adapt to different cam profiles through its linear motion capability. The follower maintains continuous contact with the cam surface while moving linearly, allowing the same mechanism to accurately follow cam profiles designed for different latitudes without changing the gear ratio.
3Ease of operation
If traditional cam and rake mechanisms are used, then sunrise and sunset times can be displayed, but friction and pivoting games are produced
Solution Approach 1:
The patent replaces the friction-prone rake pivoting mechanism with a linear sliding follower member. The follower moves linearly along the cam profile rather than pivoting, significantly reducing friction. The toothed sector then converts this linear motion to rotational motion with minimal friction at the gear interface.
4Adaptability or versatility
If multiple cams and rakes are assembled to display sunrise and sunset, then both times can be displayed, but the assembly requires a large number of parts
Solution Approach 1:
The patent divides the dual display function into two independent but parallel mechanisms: one cam-follower-toothed sector assembly for sunrise and another identical assembly for sunset. Each assembly is a complete functional unit that can be independently assembled and adjusted, reducing the overall complexity compared to a single integrated mechanism.
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 provides precise measurement of sunrise and sunset times with reduced friction and assembly complexity, allowing for easy adaptation to different cam shapes and locations, and is simpler to design and assemble, with independent measurement of sunrise and sunset times.
Implementation Method 1
first elastic means holding a first follower member against the first cam, second elastic means maintaining a second follower against the second cam
Data Source
AI summary
The invention concerns a timepiece mechanism (20) for the display of information, comprising a first cam (28A) set in motion by a pivoting means (22), first resilient means (42A) holding a first follower member (36A) against the first cam (28A), a first indicator drive wheel (56A) set in motion by the first follower member (36A), a second cam (28B) set in motion by the pivoting means (22), second resilient means (42B) holding a second follower member (36B) against the second cam (28B) and a second indicator drive wheel (60) set in motion by the second follower member (36B). The first and second follower members (36A, 36B) are guided in translation. The first indicator drive wheel (56A) cooperates with a lateral face (50A) of the first follower member (36A) substantially parallel to its direction of movement (52A), so as to allow the first cam (28A) to pivot the first indicator drive wheel (56A) by means of the first follower member (36A). The second indicator drive wheel (60) cooperates with a lateral face (50B) of the second follower member (36B) substantially parallel to its direction of movement (52B), so as to allow the second cam (28B) to pivot the second indicator drive wheel (60) by means of the second follower member (36B).