Compact Emergency Stop Switch With Nested Latch Mechanism

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Solution Overview

Problem

Emergency stop switches become larger and less compatible with size reduction, weight reduction, and portability due to constraints on shape and structure, making them unsuitable for compact applications like teaching pendants for robots.

Innovation Solution

A compact emergency stop switch design featuring a cylindrical housing with a twisting coil spring and a latch part that includes a plunger, allowing efficient use of space and preventing misoperation through a dual-direction latch function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If constraints on shape and structure are applied to ensure safety (mushroom shape, latch function with snap spring), then safety and prevention of misoperation are improved, but the size of the emergency stop switch increases

Engineering Contradiction:
ImprovesafetyVSAvoidsize
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The latch part is disposed inside the twisting coil spring, nesting one component within another. This allows the latch mechanism to occupy space that would otherwise be unused, reducing the overall volume of the switch while maintaining the safety function.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The plunger is compressed in a direction perpendicular to the pushing operation direction, utilizing a different dimensional space. This orthogonal arrangement allows the latch mechanism to function without increasing the primary dimensional footprint of the switch.

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

2Reliability

If a latch function with snap spring is used to prevent return to electrification state, then prevention of misoperation is improved, but the device complexity increases

Engineering Contradiction:
Improveprevention of misoperationVSAvoidstructure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The twisting coil spring serves multiple functions: it provides the restoring force for the button operation and simultaneously houses the latch part. This multi-functionality reduces the need for separate components, simplifying the overall structure while maintaining the prevention of misoperation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The latch part and the twisting coil spring are combined into a single integrated assembly. The latch part is disposed inside the spring, merging two functional elements into one compact unit, thereby reducing structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Volume of moving object

If space inside the switch is used efficiently by disposing parts inside the twisting coil spring, then volume is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
ImprovesizeVSAvoidmanufacturing precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The latch part is divided into distinct functional elements (plunger, urging means) that can be manufactured separately and then assembled. This segmentation allows each component to be manufactured with standard tolerances, reducing the overall manufacturing precision requirements while achieving compact integration.

Inventive Principle:
Principle #1Segmentation

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 results in a highly safe and compact switch that is compatible with advances in size reduction, weight reduction, and portability, while preventing misoperation and contact bounce.

Implementation Method 1

a twisting coil spring disposed inside the button, one end of the twisting coil spring being joined to the housing and another end of the twisting coil spring being joined to the button

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the latch part includes a plunger and is disposed inside the twisting coil spring, the plunger compressing in a direction perpendicular to the direction of the pushing operation

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3690908B1switch
Publication Date: 2022.11.09 NKK SWITCHES
  • EP3690908B1 patent drawingFigure 1
  • EP3690908B1 patent drawingFigure 2
  • EP3690908B1 patent drawingFigure 3

AI summary

The problem to be addressed by the invention is to provide a highly safe and compact switch that is adapted to improvements in portability, weight reduction and size reduction of machines, or the like. In the invention, an operating part 11 has a button 101 covering the upper part of a cylindrical housing 301 that receives a downward pushing operation and a rotational operation. A contact unit part 15 has contacts C which open by being coupled to the downward pushing operation of the button 101. A twisting coil spring 12 is disposed on the interior of the button 101, one end being joined to the housing 301, and the other end being joined to the button 1. A latch part 13 disposed to the interior of the twisting coil spring 12, has a plunger coil spring 211 that expands and contracts in a direction perpendicular to the direction of the downward pushing operation, and when a downward pushing operation is performed on the button 101, causes a sliding rod 212 to slide along an inner wall of the housing 301 while being displaced in the direction of the downward pushing operation. This allows the problem to be solved.