Elastic Spring Retainer for Tool-Free LED Assembly Mounting

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Solution Overview

Problem

Existing LED lamp mounting systems require tools and precise torque for secure attachment, which can lead to material damage due to thermal expansion mismatches and are cumbersome to install, especially when considering the need for good thermal contact and flexibility in construction tolerances.

Innovation Solution

A lamp design utilizing a support element with a web and multiple spring elements that securely holds the LED assembly in the housing without tools, providing uniform contact pressure and allowing for thermal expansion, while being easy to install and adaptable to construction tolerances, with optional features like a self-retaining seal and elastic latching elements for secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If screws or fasteners are used to firmly secure the LED assembly to the housing, then good thermal contact is achieved, but the assembly requires tools and precise torque control, increasing complexity and risk of material damage

Engineering Contradiction:
Improvethermal contact qualityVSAvoidfastening system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional screw-based mechanical fastening system with an elastic retaining element that uses elastic deformation and friction to secure the LED assembly. The retaining element is inserted into a recess and deformed elastically to engage with the LED assembly housing, eliminating the need for screws, torque control, and specialized tools while maintaining secure attachment and good thermal contact.

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

Solution Approach 2:

The patent changes the mechanical parameters of the fastening system by using an elastic material with specific hardness (40-70 HRB) and controlled elastic deformation. The retaining element is designed to deform by a specific amount during insertion and then maintain a constant holding force, replacing the rigid, torque-dependent screw system with a flexible, parameter-based elastic system that is easier to install and adjust.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple fasteners are distributed across the LED assembly to ensure good thermal contact, then thermal contact is improved, but the assembly process becomes more time-consuming and requires precise positioning

Engineering Contradiction:
Improvethermal contact uniformityVSAvoidassembly speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent merges multiple fastening functions into a single elastic retaining element. Instead of using multiple distributed fasteners, one retaining element with an extended engagement portion makes contact with multiple points on the LED assembly simultaneously during insertion. This single component provides both mechanical retention and uniform thermal contact pressure, eliminating the need for multiple separate fastening operations and precise positioning of individual fasteners.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The retaining element is pre-formed with a specific geometry including the engagement portion that will contact the LED assembly. During insertion, the elastic deformation and contact sequence are predetermined by the geometry of the retaining element and recess, ensuring that thermal contact is established uniformly across the LED assembly before final positioning, without requiring manual adjustment or precise positioning operations.

Inventive Principle:
Principle #10Preliminary action

3Strength

If rigid fastening is used to secure the LED assembly, then structural stability is achieved, but thermal expansion mismatches cause stress and material damage

Engineering Contradiction:
Improvestructural stabilityVSAvoidthermal expansion stress
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent transitions from a rigid, static fastening system to a dynamic, elastic fastening system. The retaining element is designed to deform elastically in response to thermal expansion and contraction of the LED assembly and housing. This elastic flexibility allows the system to accommodate differential thermal expansion between materials with different thermal expansion coefficients, maintaining structural stability while preventing stress concentration and material damage that would occur with rigid fastening.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent explicitly accounts for thermal expansion by using an elastic retaining element that can accommodate dimensional changes in the LED assembly and housing. The elastic material and its geometric design allow for controlled deformation that matches the expected thermal expansion ranges, ensuring that the LED assembly remains securely fastened across temperature variations without generating harmful thermal stresses.

Inventive Principle:
Principle #37Thermal expansion

4Reliability

If precise torque control is applied during screw fastening, then connection security is improved, but the assembly process requires careful operation and specialized tools

Engineering Contradiction:
Improveconnection securityVSAvoidassembly ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The elastic retaining element is designed to self-regulate the fastening force during insertion. As the retaining element is inserted into the recess and deforms elastically, it automatically generates the appropriate holding force based on its material properties and geometry. This self-service mechanism eliminates the need for external torque control devices, calibrated screwdrivers, or trained operators, making the assembly process simple and reliable while ensuring secure connection.

Inventive Principle:
Principle #25Self-service

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 enables efficient heat dissipation, easy installation without tools, and accommodates thermal expansion of materials, preventing material damage and ensuring a secure, moisture-tight, and dust-tight mounting of the LED assembly, while maintaining effective thermal contact and light emission without affecting the lamp's performance.

Implementation Method 1

several spring elements (14) which press the LED assembly (4) directly or indirectly against the housing (2)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The support element (6), which spans the LED assembly (4) with a bridge (10) and holds the LED assembly (4) in the housing (2) with several spring elements (14)

Methodology Applied
Scientific EffectMechanical support:

Implementation Method 3

heat transfer enhancers, such as a thermally conductive film or thermal paste, can also be incorporated to further improve the thermal contact between the housing, which acts as a heat sink, and the LED assembly

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

the locking element (12) is deflected by a force acting on the chamfer until it springs back over a recess in the housing

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3577391B1Tool-less installation system for an LED assembly in a lamp with a higher index of protection
Publication Date: 2021.02.24 SITECO GMBH
  • EP3577391B1 patent drawingFigure 1
  • EP3577391B1 patent drawingFigure 2~3
  • EP3577391B1 patent drawingFigure 4~5

AI summary

The invention relates to a lamp having a lamp housing (2), in which an LED assembly (4) is installed, wherein the LED assembly (4) is retained in the lamp housing (2) by means of a supporting element (6), the supporting element (6) spans the LED assembly (4) with a connecting piece (10) and supports itself by at least two support points on the lamp housing (2), and the supporting element (6) comprises a plurality of spring elements (14) on the connecting piece (10) on a side facing the LED assembly (4), which spring elements apply a resilient force which acts directly or indirectly on the LED assembly (4), to retain the assembly in the lamp housing (2).