Appliance Door Latch With Friction Release for Inside Opening

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Solution Overview

Problem

Existing household appliances lack a simplified locking mechanism that allows the appliance door to be held closed in an unlocked state while still being easily openable from the inside without the need for a cable pull mechanism.

Innovation Solution

A latching hook with a latching opening for a displaceable plunger, where an actuating device creates a frictional connection between the latching hook and plunger in the locked state, allowing the door to be pushed open by exerting force, and an electric button can cancel this connection for automatic opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a cable pull mechanism is used to open the appliance door from the inside, then the door can be opened from the inside, but the device complexity increases

Engineering Contradiction:
Improvedoor opening from insideVSAvoidcable pull mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the cable pull mechanism from the door opening system. Instead of using a cable mechanism, the invention uses a simple friction-based connection between the latching hook and plunger that can be overcome by direct pushing force from the inside, thereby removing the complex cable component while maintaining the ability to open the door from the inside

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical cable pull system with a friction-based mechanical connection. The latching hook and plunger create a frictional connection that allows the door to be held closed but can be easily overcome by pushing the door open from the inside, substituting a simple friction mechanism for the complex cable system

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

2Ease of operation

If a frictional connection is used between the latching hook and plunger, then the appliance door can be pushed open in the unlocked state, but the locking reliability may be reduced

Engineering Contradiction:
Improvedoor pushing openVSAvoidlocking security
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies dynamics by creating a system that transitions between two states: a locked state where the plunger is pushed into the latching opening creating strong frictional connection, and an unlocked state where the plunger is pulled back reducing the frictional connection. This dynamic adjustment of the frictional force allows the door to be securely locked when needed but easily opened from the inside by overcoming the friction

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the friction parameter between the latching hook and plunger based on the door state. When the door is closed, the plunger is positioned to create high friction for secure locking. When opening is required, the plunger is pulled back to reduce friction, allowing the door to be pushed open easily. This parameter change enables both secure locking and easy opening from inside

Inventive Principle:
Principle #35Parameter 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

Enables the appliance door to be securely locked in a form-fitting manner and easily opened from the inside by overcoming the frictional connection, eliminating the need for a cable pull mechanism and enhancing user safety, particularly for preventing accidental openings by children.

Implementation Method 1

a frictional connection between the latching hook and the plunger is achieved

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the household appliance comprises a spring for applying a force to the displaceable tappet

Methodology Applied
Scientific EffectElastic force: Spring

Implementation Method 3

the actuating device comprises a coil for exerting a force on the displaceable plunger

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP3071741B1Household appliance
Publication Date: 2018.05.30 BSH HAUSGERATE GMBH
  • EP3071741B1 patent drawingFigure 1
  • EP3071741B1 patent drawingFigure 2
  • EP3071741B1 patent drawingFigure 3

AI summary

The present invention relates to a household appliance (100) with a door (101) comprising a locking hook (103) with an opening (105) engaged by a movable tappet (107), characterised in that the household appliance (100) comprises an actuation device (111) for electromagnetically moving the tappet (107) in such a way that in a locked state of the appliance door (101) an interlocking connection is achieved between the locking hook (103) and the tappet (107), and in an unlocked state of the appliance door (101) a frictional connection is achieved between the locking hook (103) and the tappet (107).