Push-Push Door Lock Mechanism for Caravans

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Solution Overview

Problem

Conventional locking devices for caravan and motorhome doors require multiple locking elements and handles, which can compromise aesthetics and aerodynamics due to protruding components, and do not effectively compensate for manufacturing tolerances.

Innovation Solution

A push-push lock mechanism where the locking element and counterpart work together, allowing the door to open with a 'push' on the door leaf, utilizing a guided tour with spring support for easy opening and closing without visible handles, and an internal blocking device to prevent unwanted opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional locking devices with handles are used, then the door can be opened and closed, but the aesthetic appearance and aerodynamic properties are compromised due to protruding components

Engineering Contradiction:
Improveaesthetic appearanceVSAvoiddoor operation
Core Design Contradiction:
ShapeVSEase of operation

Solution Approach 1:

The handle element is completely removed from the door design. Instead of having a protruding handle on the door leaf, the patent uses a handleless door where the locking mechanism is operated from the interior side only, extracting the problematic external handle component entirely.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary mechanism (the interior-operated locking device with cam and latch) that mediates between the user's interior operation and the door's exterior locking function, allowing the door to be secured without external handles.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple locking elements are used to ensure secure closure, then the door can be reliably locked, but the device complexity and number of components increase

Engineering Contradiction:
Improvesecure closureVSAvoidlocking device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple locking functions into a single integrated locking device. The cam mechanism and latch work together as one unified system operated from the interior, eliminating the need for separate locking elements and handles on each side of the door.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The interior-operated locking device performs multiple functions: it locks the door in the closed position, provides a secure latch mechanism, and allows for easy interior operation. This single multi-functional device replaces what would traditionally require multiple separate locking elements.

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

3Shape

If a push-push lock mechanism is used to eliminate handles, then the aesthetic appearance improves, but the door may open unintentionally under external forces like wind or traffic pressure

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidresistance to external forces
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by designing the cam and latch mechanism to actively resist external opening forces. The cam profile is specifically designed to engage the latch in a way that creates mechanical resistance against wind pressure or traffic forces, preventing unintentional door opening.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The cam mechanism uses a curved cam profile that provides mechanical advantage and resistance against external forces. The curved geometry of the cam allows it to effectively counteract wind pressure and traffic forces that might otherwise push the door open unintentionally.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

Enhances the visual appeal and aerodynamic properties of the vehicle by reducing protruding components, simplifies door operation, and ensures secure closure even under external forces like wind or traffic pressure.

Implementation Method 1

The locking element is provided with resilient support, in particular spring support, in both the radial and axial directions

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The locking element and the locking counterpart are designed to interact as a push-push lock... In the closed position, any movement of the two elements relative to each other is prevented

Methodology Applied
Scientific EffectMechanical engagement: Mechanical Fastener

Implementation Method 3

When the force is released, however, the door leaf can spring back beyond the closed position, so that the door leaf protrudes beyond the door frame

Methodology Applied
Scientific EffectElastic recovery: Elastic Recovery

Data Source

PatentEP3287579B1Closure device for a door
Publication Date: 2022.10.12 EMKA BESCHLAGTAILE GMBH & CO KG
  • EP3287579B1 patent drawingFigure 1~2
  • EP3287579B1 patent drawingFigure 3a~3c
  • EP3287579B1 patent drawingFigure 4~5

AI summary

Locking device for a door (2) of a caravan or motorhome with a locking element (3) which engages in a locking counterpart (4) in the closed position (S), wherein the locking element (3) and the locking counterpart (4) are designed to act together as a push-push lock.