Microwave Pressure Cooker Lid Locking for Safe Vent Release

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Solution Overview

Problem

Existing microwave pressure cookers lack effective safety interlock features that prevent under-pressure locking and negative pressure issues during cooling, failing to meet current safety regulations.

Innovation Solution

A microwave pressure cooker design featuring a lock bar mechanism that blocks the blow vent when in the lock position, a pressure indicator with a spline to hold the lock tab in a raised position, and a handle with a cam section to prevent rotation back to the release position until internal pressure is released, ensuring safe operation and preventing negative pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lock bar mechanism is added to block the blow vent and prevent opening without pressure release, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lock bar combines multiple safety functions into a single component: it blocks the blow vent when engaged, prevents the lid from being removed when locked, and mechanically links to the pressure indicator system. This integration achieves comprehensive safety without proportionally increasing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The lock bar mechanism is designed to be automatically engaged or disengaged based on pressure conditions through its interaction with the cam section and pressure indicator, reducing the need for complex external control systems while maintaining safety functions.

Inventive Principle:
Principle #25Self-service

2Reliability

If a cam section and lock wall are added to prevent rotation back to release position, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cam section creates a dynamic locking mechanism where the lock tab can ride over the cam during normal operation but is prevented from returning to the release position by the lock wall, providing automatic safety engagement based on operational state without complex controls.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a pressure indicator with spline is added to hold lock tab in raised position, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pressure indicator with spline acts as an intermediary mechanism between the pressure state and the lock tab position, providing visual indication and mechanical control to ensure the lock tab is held in the correct position based on pressure conditions without requiring complex electronic or mechanical systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides a safe and reliable locking mechanism that prevents accidental opening without pressure release and addresses negative pressure issues during cooling, ensuring compliance with safety regulations and user safety.

Implementation Method 1

A blow vent is provided in the cooker lid, and a lock bar is hinged to the cooker lid in a position to block the blow vent when the lock bar is resting under its own weight

Methodology Applied
Scientific EffectMechanical blocking: Mechanical Force

Implementation Method 2

The cooker lid is placed on the base in a release position and rotated to a locking position. During this rotation the lock tab rides over the cam section and then falls adjacent the lock wall, thus sealing the blow vent

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 3

After cooking the cover is physically prevented from rotating back to the release position by the lock tab abutting the lock wall

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Force

Implementation Method 4

The spline may hold the lock bar in the raised position during rotation to the release position

Methodology Applied
Scientific EffectSpline engagement: Mechanical Force

Data Source

PatentEP2883483B1Microwave pressure cooker
Publication Date: 2016.11.30 DART IND INC
  • EP2883483B1 patent drawingFigure 1~8
  • EP2883483B1 patent drawingFigure 2
  • EP2883483B1 patent drawingFigure 3~4

AI summary

A microwave pressure cooker (12)including safety interlock mechanisms. A blow vent (76) is provided in the cooker lid (14), and a lock bar (54) is pivoted to the cooker lid (14) in a position to block the blow vent (76) when the lock bar (56) is resting under its own weight. The free end (58) of the lock bar (54) includes a lock tab (62) with a spline (72) projecting outward. The lock tab (62) extends through a slot (60) at the periphery of the lid (14). The cooker base (12) include a handle (24) with a cam section (64) ending in a lock wall (68) . The cooker lid (14) is placed on the base (12) in a release position and rotated to a locking position. During this rotation the lock tab (62) rides over the cam section (64) and then falls adjacent the lock wall (68) , thus sealing the blow vent (76) . After cooking the lid (14) is physically prevented from rotating back to the release position by the lock tab (62) abutting the lock wall (68). The user must physically lift the lock bar (54) which in turn unseals the blow vent (76) to ensure internal pressure is released. The spline (72) may hold the lock bar (54) in the raised position during rotation to the release position.