Keyswitch Series Spring Mechanism for Tactile Feedback

Solution Overview

Problem

Current keyswitches using springs or rubber domes fail to provide a balance between quick pressing and returning, leading to finger fatigue due to inconsistent force feedback and return times, making them inconvenient for rapid and sustained use in environments like electronic sports.

Innovation Solution

A keyswitch design featuring a combination of springs connected in series, where one spring is fully compressed to provide a solid height and the other remains elastically deformable, offering a light initial pressing force that transitions to a heavy return force, allowing for quick and efficient keycap operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a spring with a small spring constant is used, then the resistant force to pressing the keycap is small allowing quick pressing, but the return force is small causing long return time

Engineering Contradiction:

Improvepressing easeVSAvoidreturn speed

Core Design Contradiction:

Ease of operationVSSpeed

Solution Approach 1:

The return force mechanism is segmented into two springs with different spring constants working in parallel. The first spring (smaller constant) provides gentle initial resistance for easy pressing, while the second spring (larger constant) provides strong return force for quick recovery, resolving the contradiction between pressing ease and return speed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the effective spring constant parameter during the pressing cycle. Initially, the softer spring dominates providing low resistance. As compression progresses, the harder spring engages providing increased return force. This dynamic parameter change allows both easy pressing and fast return.

Inventive Principle:

Principle #35Parameter changes

2Speed

If a spring with a large spring constant is used, then the return force is large allowing quick return, but the resistant force is large causing finger fatigue

Engineering Contradiction:

Improvereturn speedVSAvoidpressing ease

Core Design Contradiction:

SpeedVSEase of operation

Solution Approach 1:

The return force mechanism is segmented into two springs with different spring constants working in parallel. The first spring (smaller constant) provides gentle initial resistance for easy pressing, while the second spring (larger constant) provides strong return force for quick recovery, resolving the contradiction between pressing ease and return speed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the effective spring constant parameter during the pressing cycle. Initially, the softer spring dominates providing low resistance. As compression progresses, the harder spring engages providing increased return force. This dynamic parameter change allows both easy pressing and fast return.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If a rubber dome is used, then the deformation provides variable spring constant, but the total elastic energy stored is not high resulting in slow return time

Engineering Contradiction:

Improvedeformation characteristicVSAvoidelastic energy storage

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The return force mechanism uses a composite spring system combining two metal springs with different constants rather than a single rubber dome. This composite approach maintains the adaptability of variable resistance while significantly increasing total elastic energy storage capacity through the metal springs' higher energy density.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent employs coil springs with curved helical geometry instead of a flat rubber dome structure. This curved configuration allows for greater deformation range and energy storage capacity while maintaining the variable spring constant characteristic throughout the compression stroke.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 design enables a light first and then heavy tactile feedback, reducing finger fatigue by allowing for quicker and more frequent key presses while maintaining a clear tactile sensation, enhancing user experience in fast-paced applications.

Implementation Method 1

The combination of springs includes a first spring and a second spring connected with the first spring in series... the first spring is not fully compressed and remains elastically deformable

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS10128063B2Keyswitch

Publication Date: 2018.11.13 DARFON ELECTRONICS (SUZHOU) CO LTD

AI summary

A keyswitch uses a combination of springs connected in serial for providing a return force to a keycap of the keyswitch. When the keycap moves toward a base of the keyswitch beyond a transition position, one of the springs stops continuously deforming. It leads to an increment of the elastic coefficient of the combination of springs and an increment of the elastic stored energy by the combination of springs. Therefore, during a pressing on the keycap, the keycap can provide a light force feedback and then a heavy force feedback to a user. Further, the keyswitch can use a switch with a lateral motion, which can reduce influence of a resilient force produced by the switch on the up and down movement of the keycap. The keyswitch also can use an elastic piece disposed beside the keycap, which can provide a tactile feedback to the user.