Roller Blind Spring Tensioning Through an External End Piece

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Solution Overview

Problem

Existing roller blind devices for motor vehicles require complex assembly processes and significant force to pre-tension the spring, making installation cumbersome and inefficient.

Innovation Solution

A roller blind device with a tensioning device that can be actuated from the outside to pre-tension the spiral spring after assembly, using a torsion bar with a bayonet lock mechanism and locking lugs to simplify the installation process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the spring is pre-tensioned during assembly using conventional methods, then the roller blind device is ready for operation, but the assembly process becomes complex and requires significant force

Engineering Contradiction:
Improveassembly processVSAvoidforce required for pre-tensioning
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The assembly process is segmented into two independent stages: first, assembling the winding tube with the untensioned spring into the housing; second, pre-tensioning the spring through the first end piece using the tensioning device. This segmentation eliminates the need to pre-tension the spring during initial assembly, reducing complexity and required force.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first end piece serves as an intermediary element that provides access to the spring's rotatable end through the housing wall. The tensioning device acts as a mediator that transmits rotational force to the spring from the outside, enabling pre-tensioning without disassembling the housing or applying excessive force during initial assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the spring is pre-tensioned before assembly, then the roller blind device functions correctly, but the installation process becomes cumbersome and time-consuming

Engineering Contradiction:
Improveinstallation speedVSAvoidtime required for assembly
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The housing, winding tube, and spring are assembled in their initial state without pre-tensioning the spring. The pre-tensioning action is deferred to a later stage through the first end piece, allowing rapid initial assembly and reducing installation time while ensuring proper spring tensioning before final operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The tensioning device enables the installer to pre-tension the spring from the outside through the first end piece without requiring specialized tools or complex procedures. The system is designed to be self-serviceable, allowing quick adjustment and installation by the end user.

Inventive Principle:
Principle #25Self-service

3Ease of repair

If the tensioning device is accessible from the outside through the first end piece, then maintenance and re-tensioning are simplified, but the housing structure becomes more complex

Engineering Contradiction:
Improvemaintenance accessibilityVSAvoidhousing structure
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The first end piece serves multiple functions: it closes the housing, provides structural support, and simultaneously serves as an access point for the tensioning device. This multi-functionality allows maintenance and re-tensioning operations without requiring additional openings or complex access mechanisms in the housing structure.

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

Solution Approach 2:

The tensioning device is nested within the housing structure, with its operational components positioned inside the housing but accessible through the first end piece. This nesting approach maintains a compact overall structure while providing external accessibility for maintenance operations.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

Enables easy assembly of the roller blind device without pre-tensioning the spring beforehand, allowing for tool-free operation and easy maintenance or re-tensioning of the coil spring, while maintaining a compact design.

Implementation Method 1

a coil spring (7) which is arranged within the winding tube (4) in a tensionable manner

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The tensioning device (11) has a torsion bar (12), which is rotatably arranged in the first end piece (9) of the housing (6)

Methodology Applied
Scientific EffectTorsion: Torsion Spring

Data Source

PatentEP4624259A1Roller blind device
Publication Date: 2025.10.01 FKT GMBH
  • EP4624259A1 patent drawingFigure 1
  • EP4624259A1 patent drawingFigure 2~3c
  • EP4624259A1 patent drawingFigure 4~5

AI summary

A roller blind device (1) for a motor vehicle (2), in particular a roller blind device (1) for separating a loading space (3) of a motor vehicle (2), comprises a winding tube (4), a roller blind web (5) that can be wound onto the winding tube (4), a housing (6) in which the winding tube (4) is accommodated, and a spiral spring (7) that is tensionably arranged within the winding tube (4), one end (8) of which is connected in a rotationally fixed manner to the winding tube (4) and the other end (8) of which is rotatably accommodated in the winding tube (4). The housing (6) has two end pieces (9) on which the winding tube (4) is mounted so as to be rotatable about its longitudinal axis (10), a first end piece (9) facing the rotatable end (8) of the spiral spring (7) and a second end piece (9) facing the rotationally fixed end (8) of the spiral spring (7). The roller blind device (1) has a tensioning element (11) for pre-tensioning the spiral spring (7), which can be actuated from the outside through the first end piece (9) of the housing (6).