Rotary Lock Assembly for Motor Vehicle Lighting Devices

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Solution Overview

Problem

Existing lighting devices for motor vehicles face issues with material removal during assembly, leading to particle entry due to snap hooks engaging over separating burrs on plastic lenses, and require improved fastening and positioning methods.

Innovation Solution

A rotational and translational movement assembly process is employed, utilizing hook-shaped coupling elements that deflect and snap into place, guided by ramps and contact surfaces, with stop elements preventing over-rotation, ensuring secure fastening and tolerance compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If snap hooks are used to attach the lens to the lens holder, then the assembly process is simplified, but material removal occurs leading to particle entry and potential damage

Engineering Contradiction:

Improveassembly processVSAvoidmaterial removal and particle entry

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The harmful separating burr is removed from the lens surface before assembly. The lens is pre-treated to eliminate the burr that would otherwise be caught by the snap hook during installation, preventing material removal and particle generation while maintaining the simplicity of the snap hook attachment method

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The lens is prepared in advance by removing the separating burr through mechanical means (knocking with a tool) or chemical means (solvent treatment) before the assembly process begins. This preliminary action prevents the harmful interaction between the snap hook and the burr during installation

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a rotational movement assembly method is used with coupling elements engaging behind the first structural component, then secure fastening and positioning are achieved, but the assembly process becomes more complex

Engineering Contradiction:

Improvesecure fastening and positioningVSAvoidassembly process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The coupling elements feature a curved engagement path with guide ramps that direct the rotational movement. The curved geometry of the engagement surface and guide ramps simplifies the rotational insertion process by providing natural guidance, reducing the complexity of alignment while ensuring secure fastening through the rotational locking action

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

Guide ramps and contact surfaces act as intermediary elements that mediate between the simple rotational movement and the secure fastening requirement. These intermediary features guide the coupling elements through the rotation process and ensure proper engagement, simplifying the overall assembly process while maintaining reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If guide ramps and contact surfaces are used to guide the coupling elements, then precise alignment is achieved, but the manufacturing complexity increases

Engineering Contradiction:

Improvealignment precisionVSAvoidmanufacturing complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The guide ramps, contact surfaces, and coupling elements are integrated into a single molded component rather than being separate parts. This merging of functions into one injection-molded piece achieves precise alignment through the geometry of the integrated features while simplifying manufacturing by eliminating additional machining or assembly steps

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The guide ramps and contact surfaces are designed with specific geometric parameters (angles, radii, positions) that are optimized during the molding process. By carefully selecting these geometric parameters, precise alignment is achieved through the molding process itself rather than requiring post-manufacturing adjustment or complex machining

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

The solution provides a robust and efficient assembly method that minimizes material removal and particle entry, while ensuring precise alignment and secure fastening of structural components, enhancing assembly reliability and reducing potential damage.

Implementation Method 1

During assembly of the first and second structural components, the hook-shaped coupling elements can initially be deflected according to the invention and then 'snap back' to reach the final assembly position. The deflection occurs in the z-direction.

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4202291B1Lighting device for a motor vehicle and assembly of components of the lighting device

Publication Date: 2025.06.25 MARELLI GERMANY GMBH

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AI summary

Lighting device (10) for a motor vehicle, wherein a first structural component (12) of the lighting device is connected to a second structural component (14) of the lighting device (10), characterized in that the connection between the first and the second structural component (12, 14) is formed by a rotary lock, wherein the second structural component (14) comprises two coupling elements (18) that partially engage behind the first structural component (12) in a final assembly position, and the first structural component (12) is brought into this engagement by a rotary movement (16) relative to the second structural component (14).