Roof Window Spring Assembly with Parallel Buffer Springs

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Solution Overview

Problem

Roof windows with heavy multi-layered panes face difficulties in operation across a wide range of roof inclinations due to increased weight, requiring improved spring systems for easier operation.

Innovation Solution

A spring assembly with an outer and inner spring system having different spring constants and opposite thread directions, providing enhanced stiffness and facilitating easier operation of heavy roof windows without the need for longer springs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single buffer spring is used in the lifting device, then the lifting device can maintain a compact length, but the spring constant is insufficient to facilitate operation of heavy multi-layered panes

Engineering Contradiction:
Improveease of operationVSAvoidweight of sash
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The buffer spring is divided into multiple individual springs (typically three) that are arranged parallel to each other within the lifting device. This segmentation increases the total spring constant and lifting capacity without increasing the overall length of the lifting device, thereby enabling operation of heavy multi-layered panes while maintaining a compact structure.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the spring force is increased to handle heavier panes, then operation becomes easier, but the length of the lifting device must be increased

Engineering Contradiction:
Improveease of operationVSAvoidlength of lifting device
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

Instead of using a single longer spring, the invention employs multiple shorter springs arranged in parallel. This segmentation allows the system to achieve the required total spring constant and lifting force while maintaining the original compact length dimensions of the lifting device.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple individual springs are combined in parallel within the same spatial envelope of the lifting device. This merging of multiple spring elements increases the total spring constant and lifting capacity without increasing the overall length, as all springs operate simultaneously within the same structural space.

Inventive Principle:
Principle #5Merging (Combining)

3Temperature

If multi-layered panes are used for better insulation, then thermal performance is improved, but the weight of the sash increases significantly

Engineering Contradiction:
Improvethermal insulationVSAvoidweight of sash
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The buffer spring is segmented into multiple parallel springs, increasing the total spring constant to compensate for the increased weight of the sash with multi-layered panes. This allows the window to maintain good thermal insulation performance while the lifting device can still operate the heavier sash effectively.

Inventive Principle:
Principle #1Segmentation

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 improved spring characteristics enable easier operation of roof windows with heavy multi-layered panes across various roof inclinations, maintaining the length dimensions of the lifting device and ensuring smooth opening and closing movements.

Implementation Method 1

the spring assembly comprising a main spring system and a buffer spring system inserted between the main spring system and the lifting device

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3714116B1Roof window with improved spring assembly
Publication Date: 2021.09.08 VKR HOLDING AS
  • EP3714116B1 patent drawingFigure 1~2
  • EP3714116B1 patent drawingFigure 3~4
  • EP3714116B1 patent drawingFigure 5~6

AI summary

In the roof window intended for installation in an inclined roof surface, the lifting device (10) includes a lifting arm (14) inserted between the primary frame (1) and the at least one secondary frame (2, 3)of the roof window. The lifting arm (14) has a first end (12) rotatably connected with a sledge system (30) slidably connected with the primary frame (1) in a sledge guidance (16) and a second end (13) rotatably connected with the at least one secondary frame (3).The lifting device (10) furthermore includes a spring assembly (20) configured to be coupled to the sledge system (30) and in turn the first end (12) of the lifting arm (14) by means of a coupling mechanism, such that the spring assembly (20) is able to assume an uncoupled condition and a coupled condition relative to the sledge system (30). In turn, the spring assembly comprises a main spring system (29) and a buffer spring system (28) inserted between the main spring system (29) and the lifting device (10). According to the invention, the buffer spring system (28) comprises an outer spring (281) and an inner spring (282) of substantially identical pre-defined lengths.