Winding-Stem Switch Mechanism for Thin Timepiece Movements
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Solution Overview
Problem
Existing electronic timepiece mechanisms face limitations in component layout freedom near the winding stem due to the need for a switch lever to engage with a cam, and optical sensor methods increase thickness by requiring overlap with the rotation body.
Innovation Solution
A switch mechanism with a lever detachably engaged to a gear, allowing flexible positioning and a return spring for biasing, along with a gear system that rotates in conjunction with the winding stem, enabling thin design and reduced thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a switch lever is engaged with a cam to control the winding stem rotation, then the switch mechanism can determine rotation direction and speed, but the arrangement of the switch lever is limited and component layout freedom is reduced
Solution Approach 1:
The patent replaces the cam-based mechanical switching system with an optical detection system. The optical sensor detects the rotation of the winding stem by sensing the passage of a toothed structure, eliminating the need for a cam-engaged switch lever. This substitution allows the removal of the cam mechanism and provides greater freedom in component layout while maintaining the ability to detect rotation direction and speed.
2Difficulty of detecting and measuring
If an optical sensor is used to detect winding stem rotation by overlapping with the rotation body, then rotation detection is achieved, but the movement thickness increases
Solution Approach 1:
The patent repositions the optical sensor and the toothed structure from a planar overlap arrangement to a spatial arrangement where the toothed structure is located on the winding stem and the optical sensor is positioned adjacent to it. This dimensional reconfiguration allows the optical detection to occur without requiring the sensor to overlap the rotation body in the thickness direction, thereby maintaining thin movement design while achieving accurate rotation detection.
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
Improves component layout flexibility near the winding stem while preventing an increase in timepiece movement thickness, reducing manufacturing costs through shared components and enabling thinner timepieces.
Implementation Method 1
a return spring configured to bias the lever toward the center position
Data Source
AI summary
Provided is a switch mechanism capable of improving a degree of freedom of a component layout in the vicinity of a winding stem while preventing an increase in thickness of a timepiece movement. The switch mechanism includes: a winding stem supported by a main plate; a lever side gear provided rotatably with respect to the main plate, having a first rotation axis extending in an up-down direction, and configured to rotate in conjunction with rotation of the winding stem; a circuit block having a first contact point and a second contact point; a switch lever formed to be detachably engaged with a tooth of the lever side gear and swingable according to rotation of the lever side gear, configured to swing from a predetermined swing center position to a first side to come into contact with the first contact point, and configured to swing from the swing center position to a second side to come into contact with the second contact point; and a return spring configured to bias the switch lever toward the swing center position.