Input Device Coupling Structure for Thin Resin-Metal Assembly
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Solution Overview
Problem
Existing coupling structures for input devices that couple a resin chassis member to a metal plate-like member face challenges in achieving a thinner design while maintaining high assembling efficiency and coupling strength, as they require a sufficient flexural amount for the engaging claw, which can lead to damage and increased thickness.
Innovation Solution
A coupling structure featuring a housing plate with a latch having pair of arm members extending parallel to the coupling face and a base plate with a coupling hook that is engaged between the arm members, allowing for efficient assembly and high coupling strength without excessive thickness, by using a cantilever structure that allows the latch to flex and engage the coupling hook without damaging the parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a locking hole and locking claw structure is used to couple the resin chassis member to the metal plate-like member, then the coupling strength is improved, but the structure thickness increases and assembling efficiency decreases
Solution Approach 1:
The latch structure extends in the width direction (parallel to the coupling face) rather than projecting in the thickness direction. The pair of arm members are arranged side-by-side in the width direction, allowing the coupling hook to engage between them without requiring thickness projection. This dimensional reorientation resolves the contradiction by achieving coupling strength through lateral extension rather than thickness projection.
Solution Approach 2:
The arm members are designed with flexible portions that allow them to bend elastically during assembly. When the resin chassis member is pressed onto the metal plate-like member, the arm members flex outward to accommodate the coupling hook, then spring back to secure the engagement. This dynamic flexibility enables easy assembly without requiring excessive thickness for the latch structure.
2Productivity
If the engaging claw is designed to flex sufficiently for direct pressing assembly, then assembling efficiency is improved, but the structure thickness must be increased to secure sufficient flexural amount
Solution Approach 1:
The flexural movement of the arm members occurs in the thickness direction (upward/downward bending) rather than requiring lateral movement. This allows sufficient flexural amount to be achieved within a compact thickness by utilizing the vertical space for elastic deformation, enabling direct pressing assembly without increasing overall structure thickness.
Solution Approach 2:
The arm members are designed with specific flexibility parameters - the flexible portions have controlled thickness and material properties that allow them to bend to a predetermined extent during assembly. By adjusting these parameters, the latch achieves optimal flexural amount for easy engagement while maintaining a compact overall thickness.
3Reliability
If a sufficient engagement allowance is set between the locking hole and locking claw to prevent release under impact, then the coupling reliability is improved, but the flexural amount of the locking claw must be increased which damages the locking claw
Solution Approach 1:
The arm members are designed with optimal flexibility - they bend elastically during assembly to secure the coupling hook, then spring back to provide continuous engagement force. This dynamic elastic behavior ensures reliable coupling under impact without requiring excessive initial flexural amount that would damage the locking claw. The flexibility is tuned to provide just enough movement for secure engagement while maintaining structural integrity.
4Length of stationary object
If the latch structure extends parallel to the coupling face rather than projecting toward it, then the structure can be made thinner, but the coupling mechanism becomes more complex
Solution Approach 1:
The latch is segmented into multiple functional parts: a pair of arm members for engagement, flexible portions for elasticity, and integrated formation with the resin chassis member. This segmentation allows each part to perform its specific function efficiently - the arm members provide the coupling interface, the flexible portions enable easy assembly, and the integrated formation simplifies manufacturing. The overall complexity is managed by dividing the latch into these simple, well-defined segments.
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
This solution enables a thinner input device design with high assembling efficiency and robust coupling strength, preventing damage to the engaging claw and maintaining the structure's integrity even under impact.
Implementation Method 1
a latch (56) having a pair of arm members (62, 62) extending along a direction parallel with a coupling face (50b) to the base plate (26) and whose distal ends are spaced out from each other
Data Source
AI summary
A coupling structure capable of coupling a metal plate-like member and a resin chassis member with high assembling efficiency and sufficient coupling strength while preventing damage to parts is disclosed. The coupling structure is a structure for coupling a housing plate as a resin chassis member to a base plate as a metal plate-like member in a direction to overlap the housing plate with the base plate. The housing plate includes a latch having a pair of arm members extending along a direction parallel with a coupling face to the base plate and whose distal ends are spaced out from each other, and the base plate includes a coupling hook formed upright toward the side of the housing plate and engaged between the pair of arm members.