Insulative Resin Attachment Member for Metal Wristwatch Back Cover
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Solution Overview
Problem
In electronic devices like wristwatches, the integration of charging terminals within a conductive base member often results in electrical connectivity, compromising the functionality of the terminals. Additionally, achieving high waterproofness and airtightness is challenging due to the materials used.
Innovation Solution
A component mounting member comprising a metal base member with an attachment hole and an insulative resin attachment member, where the attachment member is integrally molded with the base member using a primer layer for adhesion, preventing electrical connection and enhancing waterproofness by ensuring a secure bond between the resin and metal components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a conductive base member is used to achieve slimming and weight saving, then the device becomes more compact and lighter, but electrical connectivity between the base member and terminals occurs, compromising terminal functionality
Solution Approach 1:
The base member is divided into two distinct parts: a conductive base member (14) and a non-conductive attachment member (12). The attachment member is inserted into a through-hole of the base member, creating a segmented structure where the non-conductive portion electrically isolates the terminal from the conductive base member, preventing unwanted electrical connectivity while maintaining terminal functionality.
Solution Approach 2:
The attachment member is formed as a composite structure combining a non-conductive resin material with a conductive sheet (28). This composite material provides both electrical insulation to prevent connectivity issues and controlled electrical conductivity where needed, while also offering mechanical strength and sealing properties.
2Weight of moving object
If a conductive base member is used, then weight is reduced, but achieving high waterproofness and airtightness becomes difficult
Solution Approach 1:
A waterproof film (26) is applied to cover the outer peripheral surface of the attachment member and the inner peripheral surface of the through-hole. This thin film creates a flexible sealing barrier that prevents water and air penetration at the interface between the attachment member and base member, achieving high waterproofness and airtightness while maintaining the lightweight conductive base member structure.
Solution Approach 2:
The waterproof film acts as an intermediary sealing element between the conductive base member and the attachment member. It mediates the connection by providing both sealing functionality and mechanical bonding, ensuring waterproofness and airtightness without requiring the base member itself to be non-conductive.
3Reliability
If an insulative resin attachment member is used to prevent electrical connection, then terminal functionality is maintained, but bonding strength between resin and metal may be insufficient
Solution Approach 1:
The attachment member is constructed as a composite material combining non-conductive resin with a conductive sheet (28). This composite structure provides both electrical insulation to maintain terminal functionality and enhanced mechanical strength from the metal sheet, ensuring sufficient bonding strength between the attachment member and the base member.
Solution Approach 2:
Instead of relying solely on mechanical interference fitting or external fasteners, the patent uses adhesive bonding combined with the composite structure to achieve strong mechanical attachment. The combination of resin adhesion and metal sheet structural integrity provides robust bonding strength without compromising electrical insulation.
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
Prevents electrical connection between the metal base member and charging terminals, ensuring reliable functionality while achieving high waterproofness and airtightness, effectively addressing the limitations of previous designs.
Implementation Method 1
a primer layer for adhesion
Data Source
AI summary
A component mounting member, a case having the component mounting member, a timepiece having the case are provided by which a base member made of metal and a terminal are not electrically connected to each other even when the terminal is provided in the base member. Also, a manufacturing method therefor is provided. This component mounting member includes a back cover which is attached to a wristwatch case having an attachment hole, a terminal attachment member which is arranged in the attachment hole and thereby attached to the back cover, and charging terminals provided in and exposed from the terminal attachment member, in which the back cover is made of metal, and the terminal attachment member is made of an insulative resin. As a result of this structure, the back cover and the charging terminal provided therein are prevented from being electrically connected to each other.