Spring Fastening Element for LED Sheet Clamping Under Thermal Expansion

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Solution Overview

Problem

Lighting arrangements with LEDs face mechanical stress due to temperature fluctuations, leading to potential damage and reduced service life, as existing solutions fail to effectively adapt to thermal expansion and contraction.

Innovation Solution

A light emitting arrangement featuring a flexible fastening element that clamps a stack of sheets, allowing for thermal expansion and contraction by generating a spring force, which grips the edges of the sheets and includes an auxiliary flange for easy release, providing a robust and cost-effective clamping mechanism without additional fastening means.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rigid fastening means are used to clamp sheets together, then stable clamping force is achieved, but thermal stress causes cracking and damage during temperature fluctuations

Engineering Contradiction:
Improveclamping force stabilityVSAvoidthermal stress damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The fastening element incorporates a spring mechanism that transforms a rigid clamping structure into a dynamic one. The spring allows the fastening element to expand and contract with temperature changes, maintaining stable clamping force while accommodating thermal expansion and contraction of the sheets, thereby preventing cracking and damage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The fastening element changes its physical parameters (length, clamping force) in response to temperature variations. The spring mechanism enables the fastening element to adjust its clamping force dynamically, reducing the harmful effects of thermal stress while maintaining adequate holding strength throughout temperature fluctuations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If additional fastening means (screws, clips, adhesive) are used to secure sheets, then reliable attachment is achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveattachment reliabilityVSAvoidnumber of fastening components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fastening element integrates multiple functions into a single component: it provides clamping force to hold sheets together, accommodates thermal expansion through its spring mechanism, and attaches to the housing. This consolidation eliminates the need for separate screws, clips, or adhesive applications, reducing device complexity while maintaining reliable attachment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fastening element serves multiple purposes simultaneously: it acts as a clamping mechanism, a thermal compensation device, and an attachment element. This multi-functionality reduces the total number of components needed in the lighting arrangement while ensuring reliable sheet attachment under varying temperature conditions.

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

3Stability of the object's composition

If sheets are rigidly fixed to prevent movement, then structural stability is maintained, but thermal expansion causes stress and potential cracking

Engineering Contradiction:
Improvestructural stabilityVSAvoidthermal stress
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The spring mechanism in the fastening element creates a dynamic connection between the sheets and housing, allowing controlled movement and expansion while maintaining overall structural stability. The spring absorbs thermal stress through elastic deformation, preventing cracking while keeping the sheet assembly stable.

Inventive Principle:
Principle #15Dynamics

4Reliability

If conventional fastening methods (screws, clips, adhesive) are used, then sheets are securely attached, but mounting and recycling become time-consuming and labor-intensive

Engineering Contradiction:
Improvesheet attachmentVSAvoidmounting and recycling time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The fastening element combines attachment and clamping functions in a single integrated component that can be installed as one piece. This eliminates the need for separate operations like screwing, clipping, or applying adhesive, significantly reducing mounting time and simplifying recycling processes while maintaining secure sheet attachment.

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 solution effectively mitigates thermal stress, ensures reliable clamping, and enhances heat transfer, resulting in improved durability and performance by allowing sheets to move freely due to the spring force, reducing the need for additional fastening materials and simplifying mounting and recycling processes.

Implementation Method 1

the fastening element generates a spring force which clamps the sheets of the stack of sheets together

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

allowing the lens element to move in relation to the at least one flange portion, for example due to thermal expansion

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

a housing for dissipating heat from said carrier generated by said at least one LED during operation

Methodology Applied
Scientific EffectHeat dissipation: Heat Sink

Implementation Method 4

During operation, the heat is transferred from the LED via the conductive portion of the PCB to the heat release member

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 5

a lens element, as a top sheet, arranged for a refraction of the light emitted by said at least one LED

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2707605B1Light emitting arrangement with fastening element for clamping sheets
Publication Date: 2021.04.28 SIGNIFY HOLDING BV
  • EP2707605B1 patent drawingFigure 1~2c
  • EP2707605B1 patent drawingFigure 3a~3b
  • EP2707605B1 patent drawingFigure 3c~3d

AI summary

A fastening element (100) for clamping together a stack of sheets (410), (411) comprising at least two sheets. The fastening element comprises at least one base portion (101) extending along the stack of sheets and perpendicular to the planes of the sheets. Further, the fastening element comprises a flange portion (102) which extends substantially perpendicular from the base portion, and a pointed element (103) which extends in an acute angle with respect to the base portion. The flexible fastening element generates a spring force which clamps the sheets of the stack of sheets together between the at least one flange portion and the at least one pointed element. In this grip position, the at least one pointed element grips at least one edge of a bottom sheet of the stack of sheets, and a top sheet of the stack of sheets is allowed to move in relation to the at least one flange portion.