Emergency Exit Sign Snap-Fit Mounting for Light-Guiding Plates

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Solution Overview

Problem

Existing safety and emergency exit signs with light-guiding plates are difficult to assemble and disassemble due to complex screw connections, especially in outdoor housings with small dimensions, hindering maintenance and component replacement.

Innovation Solution

A retaining element with a snap-in mechanism, utilizing undercuts in the outer housing and perforated recesses in the light-guiding plate, allows for easy assembly and disassembly without tools, enhancing stability and simplifying the design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If screw connections are used to attach the light-guiding plate to the outer housing, then the connection stability is improved, but the assembly and disassembly complexity increases

Engineering Contradiction:

Improveconnection stabilityVSAvoidassembly complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent replaces the screw connection system with a snap-in mechanism. The retaining element features a leg with a snap projection that engages with an undercut in the outer housing, eliminating the need for threaded fasteners. This substitution maintains connection stability through the snap-fit engagement while dramatically simplifying assembly and disassembly operations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the fastening function from the main housing structure by introducing a separate retaining element. This retaining element can be independently attached to the outer housing via snap-in connection, and then used to secure the light-guiding plate, separating the mounting operation from the housing assembly itself.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If screw connections are used to attach the light-guiding plate to the outer housing, then the connection reliability is improved, but the ease of operation deteriorates

Engineering Contradiction:

Improveconnection reliabilityVSAvoidease of assembly

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The snap-in mechanism replaces the screw system, allowing the retaining element to be quickly inserted into the outer housing without tools. The leg with snap projection engages the undercut in a single motion, making assembly as easy as plug-and-play while maintaining reliable connection through the interlocking geometry.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The snap-in mechanism is self-aligning and self-securing. The retaining element's leg automatically finds and engages the undercut in the outer housing without requiring precise alignment or additional fastening steps, making the operation intuitive and tool-free while ensuring reliable attachment.

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If multiple components are secured with screw connections in a compact outdoor housing, then the stability of component attachment is improved, but the ease of repair deteriorates

Engineering Contradiction:

Improvecomponent attachment stabilityVSAvoidease of component replacement

Core Design Contradiction:

Stability of the object's compositionVSEase of repair

Solution Approach 1:

The snap-in mechanism replaces screw fastening for the retaining element, allowing maintenance personnel to quickly remove the retaining element and replace components like the light-guiding plate without tools. The snap connection provides sufficient holding stability during operation but releases easily when needed for maintenance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent segments the mounting system into distinct functional elements: the outer housing, the retainable component (light-guiding plate), and the retaining element with snap-in capability. This segmentation allows the retaining element to be independently removed for component replacement while maintaining stable attachment during normal operation.

Inventive Principle:

Principle #1Segmentation

4Ease of manufacture

If a simple snap-in mechanism is used without undercuts, then the ease of manufacture is improved, but the stability of the connection deteriorates

Engineering Contradiction:

Improveease of retaining element manufactureVSAvoidconnection stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The undercut is created only in the specific location where the snap-in engagement occurs, rather than requiring complex features throughout the housing. This localized geometric modification provides the necessary mechanical interlocking for stable connection while keeping the overall manufacturing process simple and compatible with standard molding techniques.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP4481719B1Safety and/or rescue sign lamp

Publication Date: 2026.04.08 DIN DIETMAR NOCKER FACILITYMANAGEMENT GMBH

Figure 1
Figure 1a~1b
Figure 2

AI summary

A safety and/or emergency exit sign (1), particularly for an emergency lighting system, is shown. Easy assembly and/or disassembly can be enabled if the outer housing (5) has at least one undercut (12a, 12b) with which the snap-in element (11) of the retaining element (6, 7) snaps into place, and if the light-guiding plate (3) has at least one retaining recess (13, 14), in particular a perforated one, into which the web (8) of the retaining element (6, 7) engages.