Door Lock with Locking Element Detection for Forced-Opening Prevention

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Solution Overview

Problem

Existing door locks for electrical household appliances lack reliable mechanisms to detect manipulation or forced opening, which can compromise safety and require additional components to ensure proper closure, increasing manufacturing costs.

Innovation Solution

A door lock system with a rotatably mounted rotary gripper and a movably arranged locking element that moves under spring preload to detect the presence of a locking body, transitioning to a fault position if manipulated or forced open, triggering a defined switching state in an electrical switch to prevent appliance operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a blocking slide is used to prevent rotary gripper rotation, then the door lock structure is simple, but it cannot detect manipulation or forced opening scenarios

Engineering Contradiction:

Improvedetection of manipulation or forced openingVSAvoidadditional detection mechanisms

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The locking element is designed to perform multiple functions: it acts as both a blocking mechanism (preventing rotary gripper rotation) and a detection mechanism (detecting manipulation or forced opening through its position relative to the locking body). This multi-functionality eliminates the need for separate detection mechanisms, maintaining structural simplicity while improving reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The locking element serves itself by using its own positional changes to detect fault conditions. When manipulation or forced opening occurs, the locking element's position relative to the locking body changes, and this self-detection capability is built into the existing locking mechanism without requiring external sensors or additional components

Inventive Principle:

Principle #25Self-service

2Reliability

If additional detection mechanisms are added to detect manipulation or forced opening, then safety is improved, but manufacturing costs increase

Engineering Contradiction:

Improvesafety detection capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The detection function is merged with the existing locking mechanism. The locking element's position relative to the locking body serves as both the locking state indicator and the fault detection indicator, combining what would traditionally be separate functions into a single integrated system

Inventive Principle:

Principle #5Merging (Combining)

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 system provides reliable detection of improper closure or forced opening, preventing appliance operation and reducing the need for additional safety mechanisms, thus maintaining safety and minimizing component costs.

Implementation Method 1

a spring-loaded locking element slides into a locking position

Methodology Applied

Scientific EffectSpring preload: Spring

Data Source

PatentEP4431683B1Door lock for an electric household appliance

Publication Date: 2025.07.30 EMZ HANAUER GMBH & CO KGAA

Figure 1
Figure 2a~2c
Figure 3a

AI summary

A door lock for an electrical household appliance comprises a rotatably mounted rotary gripper (30) which, when the appliance door is closed, moves from an open rotary position to a closed rotary position and, in the closed rotary position, holds a locking element that moves relatively close to the rotary gripper as the door closes, thus keeping the door closed. Furthermore, the door lock comprises a movably arranged, in particular linearly guided, locking element which, when the door is closed, moves from a ready position, in which the locking element is supported against the rotary gripper, to a locking position under the influence of a spring preload, in which the locking element blocks the rotary gripper from rotating into the open rotary position. According to the invention, when the door is closed, the locking element is supported against the locking element in the locking position.This allows the presence/absence of the locking mechanism to be additionally detected using the locking element, which already provides a blocking function for the rotary gripper when the door is closed. A simple door lock design with minimal component and assembly effort is possible.