Control Knob Elastic Locking Mechanism for Cooking Appliance Safety

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Solution Overview

Problem

Existing cooking appliances lack a reliable locking mechanism for control knobs, leading to potential safety issues when users unintentionally apply excessive force, causing the knobs to be disengaged from the shaft.

Innovation Solution

A cooking appliance design featuring a control knob with a guiding portion made of elastic material, equipped with a protrusion that engages with a corresponding recess on the shaft, creating a locked position that prevents the knob from being easily removed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a control knob is connected to a shaft without a locking mechanism, then the control knob can be easily removed and installed, but the control knob may be accidentally disengaged during normal use

Engineering Contradiction:
Improveease of knob installationVSAvoidknob retention reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The guiding portion is made of elastic material that can dynamically change its state between locked and unlocked positions. The material's elasticity allows the protrusion to engage with the recess for secure operation, and to be temporarily deformed for easy removal when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The elastic material changes its physical parameters (shape, rigidity) in response to applied force. During normal use, the material maintains a rigid locked state; during removal, the material temporarily becomes more compliant to allow disengagement from the recess.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a locking mechanism is added to prevent knob disengagement, then the reliability of knob retention is improved, but the complexity of the device increases

Engineering Contradiction:
Improveknob retention reliabilityVSAvoidcontrol knob structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent discards the need for complex separate locking mechanisms by recovering and utilizing the inherent elastic properties of the guiding portion material. The elastic material itself provides the locking function through its ability to engage and disengage from the recess without additional components.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The locking function is merged with the guiding portion itself rather than being a separate mechanism. The protrusion on the guiding portion and the recess on the shaft are integrated into the basic knob structure, eliminating the need for additional locking components.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the guiding portion is made of elastic material with protrusion and recess engagement, then the control knob is prevented from accidental removal, but the control knob becomes more difficult to remove when needed

Engineering Contradiction:
Improveknob retention reliabilityVSAvoidease of knob removal
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The elastic material provides dynamic behavior where the engagement strength can be temporarily overcome by sufficient force. The material's ability to deform elastically allows the protrusion to be pushed out of the recess when intentional removal force is applied, while maintaining secure engagement during normal use.

Inventive Principle:
Principle #15Dynamics

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 solution effectively prevents accidental disengagement of the control knob during normal use while allowing for easy demounting when needed, enhancing the safety and usability of the cooking appliance.

Implementation Method 1

The guiding portion is made of elastic material, preferably plastic material

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4015914B1A cooking appliance having a control knob
Publication Date: 2025.06.04 BSH HAUSGERATE GMBH
  • EP4015914B1 patent drawingFigure 1
  • EP4015914B1 patent drawingFigure 2
  • EP4015914B1 patent drawingFigure 3

AI summary

The present invention proposes a cooking appliance (100) comprising a main body (110), a control panel (120) provided on the main body (110), a switch (30) for adjusting a power level of a heat source, the switch (30) comprising a shaft (20) extending through the control panel (120) and a control knob (10) connected to the shaft (20) for rotating the shaft (20), wherein said control knob (10) comprising a knob body (11) having a guiding portion (12) in which the shaft (20) is arranged to extend. The present invention also proposes a method of mounting a control knob (10) on a shaft (20) of a cooking appliance (100) comprising the steps of: providing the cooking appliance (100) wherein the cooking appliance (100) comprises a main body (110); a control panel (120) provided on the main body (110), and a switch (30) having a shaft (20) extending through the control panel (120) for adjusting a power level of a heat source, creating a recess (21) on the shaft (20) of the switch (30); providing a control knob (10) wherein the control knob (10) has a guiding portion (12) in which the shaft (20) is arranged to extend, and the guiding portion (12) having at least one protrusion (13) shaped and dimensioned with respect to the recess (21) on the shaft (20), and mounting the control knob (10) to the shaft (20) such that the protrusion (13) and the recess (21) engage each other at a locked position in which the control knob (10) and the shaft (20) rotate together.