Latch Holder Lever Mechanism for Self-Weight Automatic Door Opening

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing automatic door opening structures for cooking appliances, particularly pull-down doors, face challenges such as complex design requirements, heat sensitivity of components, and inefficient control mechanisms, leading to issues with door opening speed control and reliability.

Innovation Solution

A cooking appliance with a latch system where two latches can operate independently, using a lever mechanism to open the door by self-weight, and a damping system that controls the opening speed, along with a control method employing uninterrupted AC power to ensure accurate motor positioning and error monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high output power driver is used to open the door to overcome elasticity applied to the door, then the door can be opened reliably, but the driver becomes heavy and is greatly affected by inertial force, causing positioning errors

Engineering Contradiction:
Improvedoor opening reliabilityVSAvoiddriver weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the heavy mechanical cam-driven system with an electrical motor-driven system. The motor (1610) with pushing member (1530) directly pushes the latch (200) without requiring a heavy cam mechanism, thereby reducing driver weight while maintaining reliable door opening capability through controlled electrical actuation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters of the driving system by using a motor with controlled pushing force instead of a high-output cam mechanism. The motor can apply sufficient force to overcome latch elasticity while maintaining low weight, and the pushing member design ensures reliable latch engagement without requiring excessive driving force.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the cam stops in the incorrect position, then the latch may not be completely mounted onto the latch holder to lock onto the latch holder, but using a heavy driving system makes immediate stopping difficult due to inertial force

Engineering Contradiction:
Improvelatch positioning precisionVSAvoiddriving system weight
Core Design Contradiction:
Manufacturing precisionVSWeight of moving object

Solution Approach 1:

The patent replaces the mechanical cam positioning system with an electric motor control system. The motor (1610) can be precisely controlled to stop at the correct position by cutting power when the pushing member (1530) engages the latch (200), eliminating the inertial stopping problems of heavy cam systems while achieving accurate latch positioning.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent incorporates a sensor (1410) that detects when the latch (200) is properly engaged with the latch holder (110). This feedback mechanism ensures accurate positioning by confirming proper engagement, and the controller can adjust motor operation based on sensor input to ensure reliable latching.

Inventive Principle:
Principle #23Feedback

3Device complexity

If two latches are linked with each other to operate simultaneously, then the door opening mechanism can be simplified, but in the case of a pull-down door, the distance between two latches is longer making it not simple to link them with each other

Engineering Contradiction:
Improvelatch linkage complexityVSAvoiddistance between latches
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The patent divides the door opening mechanism into independent latch units (left latch 200 and right latch 200) that operate separately rather than being mechanically linked. Each latch has its own engagement mechanism with the latch holder, eliminating the need for complex linkage structures while accommodating the longer distance between latches on pull-down doors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent designs a universal latch mechanism that can be applied to both swing doors and pull-down doors regardless of the distance between latches. The same latch holder and latch design works for both door types, providing multi-functionality and eliminating the need for special linkage structures for different door configurations.

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

4Power

If the cam directly connects to a driving means such as a motor, then the driving force can be transmitted efficiently, but the driving system becomes very heavy requiring a motor that generates as much power as the driving force of the cam or a speed reducer

Engineering Contradiction:
Improvedriving force transmission efficiencyVSAvoiddriving system weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The patent replaces the cam-based mechanical transmission system with a direct motor-driven system. The motor (1610) directly pushes the latch (200) through the pushing member (1530), eliminating the need for heavy cam mechanisms and speed reducers while maintaining efficient power transmission through direct electrical-mechanical actuation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables reliable, efficient, and controlled automatic door opening with reduced component weight and heat sensitivity, allowing for smooth operation and precise control of door opening speed, enhancing the appliance's functionality and user experience.

Implementation Method 1

a spring configured to apply elastic force to the door in a direction, in which the door is closed

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

the door is configured to open by self-weight such that force that the door opens by means of self-weight is greater than force applied by the spring

Methodology Applied
Scientific EffectSelf-weight: Gravitation

Data Source

PatentEP3546689A1Latch holder having automatic opening structure and cooking appliance with automatic opening door using latch holder
Publication Date: 2019.10.02 LG ELECTRONICS INC
  • EP3546689A1 patent drawingFigure 1
  • EP3546689A1 patent drawingFigure 2
  • EP3546689A1 patent drawingFigure 3

AI summary

A lever pushes a latch drawn into a hook accommodating space in a latch holder in a direction where a door opens is installed in the latch holder, and the latch is released from the latch holder using the lever. The door that is opened by an initial opening angle by the latch holder releasing the latch automatically opens by self-weight of the door.