Wristwatch Switch Device Vent Passage Waterproofing
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Solution Overview
Problem
Existing switch devices for wristwatches face challenges in ensuring waterproofness while maintaining operability, as thick waterproof sheets require high pressure for deformation, leading to poor operability, and thin sheets are easily damaged, compromising waterproofness.
Innovation Solution
A switch device design featuring a cylindrical member with a small-diameter and large-diameter section, an operation member with a shaft and head section, and a vent passage for air exchange between the cylindrical member and the case, utilizing waterproof rings and a coil spring for smooth operation and pressure equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the waterproof sheet is made thicker, then waterproofness is improved, but operability deteriorates due to requiring larger pressure load for deformation
Solution Approach 1:
The invention divides the waterproofing function into two separate components: a rigid waterproof sheet that maintains waterproofness and a soft sealing member that provides ease of operation. The waterproof sheet is positioned at the bottom of the recess to prevent water ingress, while the sealing member surrounds the protruding portion to seal the gap between the cylindrical member and case, allowing the button to be pressed with minimal force.
Solution Approach 2:
Different parts of the waterproofing system are given different material properties: the waterproof sheet is made rigid to resist water penetration, while the sealing member is made soft and elastic to deform easily during button operation. This local differentiation of material quality allows each component to optimize its specific function without compromising the other.
2Ease of operation
If the waterproof sheet is made thinner, then operability is improved, but waterproofness deteriorates due to easy damage
Solution Approach 1:
The waterproofing function is segmented between the rigid waterproof sheet and the soft sealing member. The waterproof sheet can be thin since its primary role is to provide a water barrier, while the sealing member compensates for any gaps or deformations, ensuring waterproofness is maintained even with a thinner waterproof sheet.
Solution Approach 2:
The waterproofing system uses a composite structure combining a rigid waterproof sheet with a soft sealing member made of elastomeric material. This composite approach allows the thin waterproof sheet to maintain its waterproofing function while the sealing member provides the necessary flexibility and damage resistance.
3Ease of manufacture
If the waterproof sheet is made of soft synthetic resin, then ease of manufacture is improved, but reliability deteriorates due to easy deterioration
Solution Approach 1:
The sealing member is specifically positioned to contact the operation member during operation, providing localized sealing where mechanical stress and wear occur. This concentrates the durability requirements on the sealing member rather than the entire waterproof sheet, allowing the waterproof sheet to be manufactured easily while the sealing member provides long-term reliability.
Solution Approach 2:
The invention uses a composite sealing system combining a synthetic resin waterproof sheet with an elastomeric sealing member. The elastomeric material provides superior durability and resistance to deterioration where it is most needed (at the sealing interface), while the synthetic resin waterproof sheet maintains ease of manufacture for the main waterproofing barrier.
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 design ensures waterproofness and improved operability by maintaining air pressure equality between the internal and external environments, preventing water and dust ingress while allowing smooth sliding of the operation member.
Implementation Method 1
a coil spring arranged in the second cylindrical section and functioning to restore the operation member in the initial state
Implementation Method 2
a vent passage that allows air inside the second cylindrical section and air outside the case to pass through a vent hole provided in the cylindrical member and a gap between an outer surface of the cylindrical member and an outer surface of the case for ventilation
Data Source
AI summary
A switch device including a case having a through hole, a cylindrical member including a first cylindrical section having a small diameter arranged in the through hole of the case and a second cylindrical section having a large diameter arranged on an outer portion of the case, an operation member including a shaft section slidably inserted into the first cylindrical section and a head section slidably arranged in the second cylindrical section, a waterproof member provided between an inner peripheral surface of the second cylindrical section and an outer peripheral surface of the head section, and a vent passage that allows air inside the second cylindrical section and air outside the case to pass through a vent hole provided in the cylindrical member and a gap between an outer surface of the cylindrical member and an outer surface of the case for ventilation.