Switch Terminal Contact Spring Compression for Stable Conductivity

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Solution Overview

Problem

Conventional switches, such as the 'miniature switch' and 'push button switch', fail to provide sufficient contact pressure and reliable electrical conduction due to inadequate elastic properties and constant contact pressure, leading to poor operational feeling and reliability.

Innovation Solution

A switch design featuring a housing, plunger, return spring, and terminal contact spring, where the terminal contact spring is compressed upon contact with terminals, enhancing contact pressure and providing a satisfactory operational feeling by varying elastic force feedback to the operator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a spring with a large diameter coil portion and small diameter coil portion disposed in series is used, then the stroke in the compression direction can be ensured, but the elastic property for bias in the return direction becomes insufficient

Engineering Contradiction:

Improvecompression strokeVSAvoidelastic force for return bias

Core Design Contradiction:

Length of moving objectVSForce

Solution Approach 1:

The spring is divided into two distinct portions: a large diameter coil portion for compression stroke and a small diameter coil portion for return bias. This segmentation allows each portion to optimize its function independently, resolving the contradiction between stroke length and elastic force.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the spring have different diameters to provide different local properties. The large diameter portion provides compliance for stroke, while the small diameter portion provides stiffness for return bias, ensuring both requirements are met simultaneously.

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If the large diameter coil portion is used first during plunger compression, then overlapping of wires can be prevented, but the build-up of elastic force becomes slow

Engineering Contradiction:

Improvewire overlapping preventionVSAvoidelastic force build-up speed

Core Design Contradiction:

Stability of the object's compositionVSSpeed

Solution Approach 1:

The spring is pre-configured with the small diameter coil portion positioned to engage first during compression. This preliminary arrangement ensures that the stiffer small diameter portion builds elastic force quickly before the larger diameter portion engages for stroke absorption.

Inventive Principle:

Principle #10Preliminary action

3Force

If a contact spring is disposed outside the push button, then the return spring can provide moderate elastic property, but the contact pressure against terminals becomes constant and insufficient

Engineering Contradiction:

Improvereturn spring elastic propertyVSAvoidcontact pressure against terminals

Core Design Contradiction:

ForceVSStress or pressure

Solution Approach 1:

The return spring and contact spring are merged into a single integrated spring structure. This combination allows the spring to simultaneously provide both the moderate elastic property for return bias and the increasing contact pressure against terminals as compression progresses.

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 switch achieves increased contact pressure and reliability of electrical conduction, with stable conductivity even under repeated contacts, and enhanced operational feeling through the compression and expansion of the terminal contact spring.

Implementation Method 1

a return spring that biases the plunger in the return direction and is compressed by a slide of the plunger in the press direction

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a terminal contact spring that makes contact with the terminals so as to bring the terminals into a conductive state by the slide of the plunger in the press direction; the terminal contact spring is compressed according to the slide of the plunger in the press direction under a contact state of making contact with the terminals

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS9236199B2Switch

Publication Date: 2016.01.12 OMRON CORP

AI summary

This invention provides a switch including a housing, a plunger that slides in a press direction or a return direction with respect to the housing, a return spring that biases the plunger in the return direction and is compressed by a slide of the plunger in the press direction, a plurality of terminals that are brought into a conductive state according to a predetermined position of the plunger, and a terminal contact spring that makes contact with the terminals so as to bring the terminals into a conductive state by the slide of the plunger in the press direction. The terminal contact spring is disposed so as to be compressed according to the slide of the plunger in the press direction under a contact state of making contact with the terminals.