Gas knob skirt retainer

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Solution Overview

Problem

Control knobs for gas cooking appliances face issues with spring misalignment during assembly, leading to difficulties in installation and function, as springs become loose parts upon disassembly and require precise orientation of locating sleeves or tubes for retention.

Innovation Solution

The control knob assembly incorporates spring retaining means, such as angularly equidistant spring retainers or grooves, on either the knob or skirt to securely hold the spring in place, ensuring proper alignment and retention during assembly and disassembly, allowing the skirt and knob to rotate independently or together with complementary formations for smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a gas knob is left protruding when not in use, then it is easy to locate and operate, but it creates a safety hazard by being accessible to children and unauthorized persons

Engineering Contradiction:
Improveease of locating and operating gas knobVSAvoidsafety hazard from unauthorized access
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The gas knob assembly transitions between two dynamic states: protruding (extended) for easy operation and retracted for safety. The spring mechanism enables automatic transition between these states based on operational need, allowing the system to adapt its configuration dynamically rather than remaining fixed in one position.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The gas knob is nested within a cavity in the appliance housing when retracted, with the retainer holding it in place. When activated, the knob extends outward from this nested position. This nesting arrangement keeps the knob hidden and inaccessible during normal conditions while allowing easy access when needed.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If a spring mechanism is used to retract the gas knob, then safety is improved by automatic retraction, but the device complexity increases

Engineering Contradiction:
Improvesafety through automatic retractionVSAvoidcomplexity of spring mechanism and retainer
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring mechanism is designed to be self-acting, automatically retracting the gas knob without requiring external control systems, motors, or complex actuation mechanisms. The spring stores potential energy that is automatically converted to kinetic energy to return the knob to its retracted position, making the system self-regulating and reducing overall device complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The retainer acts as an intermediary component that simplifies the interaction between the spring mechanism and the gas knob. It provides a simple engagement and disengagement interface, allowing the spring to efficiently transfer its retraction force to the knob through a straightforward mechanical connection rather than requiring a complex direct coupling system.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the gas knob is completely hidden when retracted, then safety is improved, but ease of operation decreases as users must search for it

Engineering Contradiction:
Improvesafety through hidden positionVSAvoiddifficulty of locating gas knob
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The gas knob is provided with a colored indicator element that becomes visible when the knob is in its retracted position within the cavity. This visual indicator allows users to easily locate the knob's position without it protruding, maintaining safety while improving findability. The color change or visibility change provides immediate visual feedback about the knob's state.

Inventive Principle:
Principle #32Color changes

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 simplifies the assembly process by maintaining spring alignment and preventing loose parts, enhancing the reliability and ease of use of the control knobs while ensuring proper operation of gas cooking appliances.

Implementation Method 1

Some control knobs include compression springs against which the pushing operation is made, so that the control knob is biased away from the position which causes gas ignition

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3433696B1Gas knob skirt retainer
Publication Date: 2021.05.12 ELECTROLUX HOME PROD PTY LTD
  • EP3433696B1 patent drawingFigure 1
  • EP3433696B1 patent drawingFigure 2
  • EP3433696B1 patent drawingFigure 3~4

AI summary

A control knob assembly to control an operation of an appliance comprises a skirt adapted to engage the appliance. The skirt has a side wall, and a front face which in use will face away from the appliance. The assembly has a knob adapted to engage with the skirt, the knob having a side wall, the knob being adapted to move axially relative to the skirt. A spring is located between the knob and the skirt, to bias the knob and the skirt away from each other. The skirt and/or the knob has a spring retaining means adapted to retain the spring.