Key Switch V-Gear Link Height Reduction

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Solution Overview

Problem

Existing key switches in low-profile keyboards face challenges in reducing height without compromising operability and structural reliability, particularly due to the configuration of guide and bearing portions which can lead to disassembly and vertical movement displacement.

Innovation Solution

A key switch design featuring a V-shaped gear link configuration with a frame member that supports pivot axles and includes a cutout bearing portion, allowing smooth rotation and reducing the overall height by positioning link members on the lateral side of the frame member, eliminating the need for a housing that increases height.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If guide portions or bearing portions are formed on the upper surface of the housing disposed above the membrane switch sheet, then the key switch can be assembled with link members, but the thickness of the housing is included in the height dimension of the key switch, increasing overall height

Engineering Contradiction:
Improvestructural reliabilityVSAvoidheight of key switch
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent extracts the bearing portions from the housing structure and relocates them to the key top. Specifically, bearing portions are formed at positions near the center of the inner surface of the key top, allowing link members to be pivotally supported directly by the key top without requiring a housing above the membrane switch sheet. This extraction eliminates the housing thickness from the height dimension while maintaining the necessary bearing function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the spatial arrangement by positioning bearing portions on the inner surface of the key top (a different dimensional plane) rather than on the upper surface of the housing. This dimensional repositioning allows the link members to be supported from above without requiring additional height, as the bearing function is moved to the key top's internal surface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Length of moving object

If bearing portions are formed at positions near the center of the inner surface of the key top, then the key switch height is reduced, but external force applied to the outer edge of the key top increases the force acting to separate the bearing portion from the pivot axle, potentially causing disassembly

Engineering Contradiction:
Improveheight of key switchVSAvoidresistance to disassembly
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent introduces asymmetry in the force distribution by positioning bearing portions near the center of the key top's inner surface, creating a deliberate offset from the outer edge where force is applied. This asymmetric arrangement, combined with the key top's structural design, allows the central bearing portions to resist external forces applied at the periphery through the key top's rigidity, preventing disassembly while maintaining low height.

Inventive Principle:
Principle #4Asymmetry

3Ease of operation

If the pair of link members are meshed in a gearing manner at one-end regions, then the key top can be supported and directed in a vertical direction, but the configuration complexity increases compared to simpler support mechanisms

Engineering Contradiction:
Improvevertical movement guidanceVSAvoidlink member configuration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into the link members: they provide structural support, guide vertical movement through gear-like meshing at one end, and enable rotational movement through pivot axles at the other end. By combining these functions into a single integrated component rather than using separate support and guidance mechanisms, the overall device complexity is reduced while maintaining ease of vertical operation.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively reduces the key switch's height while maintaining operability and structural reliability, preventing disassembly and vertical movement displacement, and ensuring the key top remains aligned during use.

Implementation Method 1

each of the pair of link members is meshed in a gearing manner at one-end regions thereof with each other

Methodology Applied
Scientific EffectGearing: Gear

Implementation Method 2

the pair of link members rotate about the pivot axles in a mutually interlocking manner

Methodology Applied
Scientific EffectRotation:

Implementation Method 3

respective slide portions of the link members move substantially in a horizontal direction under the guiding action of the guide portion

Methodology Applied
Scientific EffectGuiding:

Data Source

PatentEP2040275B1Key switch and keyboard
Publication Date: 2013.04.03 FCL COMPONENTS LTD
  • EP2040275B1 patent drawingFigure 1
  • EP2040275B1 patent drawingFigure 2
  • EP2040275B1 patent drawingFigure 3~4

AI summary

A key switch including a base section, a key top, a pair of link members and a switching mechanism. Each link member is provided, at one end region thereof, with a toothed portion meshable with a toothed portion of another link member in a gearing manner and a pivot axle pivotably joined to the base section, and at another end region, with a slide portion slidably engaged with the key top. The base section includes a support plate and a frame member, the frame member being fixedly attached to the upper surface of the support plate. The frame member is provided with a bearing portion pivotably receiving and supporting the pivot axle of each link member. The first end region of each link member is disposed on a lateral side of the frame member and closely to the upper surface of the support plate.