Wristwatch Switch Cylindrical Member Segmentation for Case Thickness Reduction
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Solution Overview
Problem
Existing switch devices for wristwatches are structurally unstable due to the cylindrical member being easily displaced in the radial direction, leading to a larger outer diameter and inner diameter of the through hole, which increases the thickness of the wristwatch case.
Innovation Solution
A switch device with a cylindrical member that includes a small diameter section press-fitted into the through hole and a large diameter section protruding outside, held by an operation member with an elastic retaining member, providing three-point support and reducing the outer and inner diameters, thus stabilizing the cylindrical member and thinning the wristwatch case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cylindrical member is held with the elastic member provided between the inner circumferential surface of the through hole and the outer circumferential surface of the cylindrical member, then the cylindrical member can be easily displaced in the radial direction to reduce shear force on the operation member, but the cylindrical member becomes unstable and requires a larger outer diameter to ensure strength
Solution Approach 1:
The cylindrical member is divided into two distinct sections: a first cylindrical section with a larger outer diameter that fits into the through hole and provides structural strength, and a second cylindrical section with a smaller outer diameter that protrudes outside the case and provides operational stability. This segmentation allows each section to optimize for its specific function without compromising the other.
Solution Approach 2:
Different sections of the cylindrical member are given different diameters to satisfy different functional requirements. The first cylindrical section has a larger diameter to provide strength and fit securely in the through hole, while the second cylindrical section has a smaller diameter to reduce overall size and improve case thickness. This local differentiation resolves the contradiction between strength and stability.
2Strength
If the cylindrical member is formed with a larger outer diameter to ensure strength, then the strength of the cylindrical member is ensured, but the inner diameter of the through hole must also be larger, causing an increase in the thickness of the wristwatch case
Solution Approach 1:
The cylindrical member is segmented into a first cylindrical section with larger diameter for strength and a second cylindrical section with smaller diameter for compactness. This allows the through hole to be sized for the smaller second section, reducing case thickness while the first section maintains the required strength.
Solution Approach 2:
The cylindrical member exhibits local quality variation with different diameters at different sections. The first cylindrical section has a larger outer diameter to ensure strength, while the second cylindrical section has a smaller outer diameter to minimize case thickness. This resolves the contradiction by optimizing each section for its specific requirement.
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 solution ensures the cylindrical member is firmly attached, reducing the outer diameter by 20% and the wristwatch case thickness by 10%, while maintaining strength and stability, and improves operability and waterproofing.
Implementation Method 1
the elastic member provided between the inner circumferential surface of the through hole of the wristwatch case and the outer circumferential surface of the cylindrical member is elastically deformed
Implementation Method 2
a small diameter section press-fitted into the through hole
Data Source
AI summary
A switch device including a case which is provided with a through hole and has a built-in module, a cylindrical member which is attached to the through hole of the case and whose inner end portion protrudes inside the case and is held in the module and outer end portion protrudes outside the case, and an operation member including a shaft section which is arranged inside the cylindrical member in a manner to be slidable in an axial direction of the cylindrical member so as to operate the module and a head section which is provided on an outer end portion of the shaft section and covers and slidably holds the outer end portion of the cylindrical member.