Roof Window Lifting Device with Sledge Guide and Spring Assembly

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Solution Overview

Problem

Existing roof window lifting devices for inclined roof surfaces lack stability and safety, leading to difficulties in operability and potential accidents during opening and closing.

Innovation Solution

A roof window lifting device with a sledge guide and lifting arm configuration, featuring a spring assembly and adjustment arm, which balances forces along a central plane, ensuring stable and low-friction movement, and includes a sash wheel for minimal friction connection to the secondary frame, providing secure and durable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a lifting device is provided to balance the weight of movable components, then ease of operation is improved, but stability and safety deteriorate due to potential accidents and failures during opening or closing

Engineering Contradiction:
Improveease of operationVSAvoidstability and safety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The lifting device uses a spring assembly that provides a counterbalancing force to offset the weight of the movable components (sash and intermediate frame). The spring is configured to exert an upward force that balances the downward gravitational force, allowing the window to be opened and closed with minimal effort while maintaining stable equilibrium throughout the range of motion.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The lifting arm acts as an intermediary mechanical element between the spring assembly and the movable components. It transmits the balancing force from the spring to the sash and intermediate frame, enabling smooth operation while isolating the user from direct interaction with the heavy components and potential failure modes.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the sash structure is connected with an intermediate frame to enable rotation for cleaning, then versatility is improved, but device complexity increases due to multiple hinge arrangements

Engineering Contradiction:
ImproveversatilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of the sash and intermediate frame by connecting them through a hinge arrangement that allows the intermediate frame to rotate relative to the sash. This integration enables the cleaning function (rotation) while maintaining the structural unity and simplifying the overall design compared to separate assemblies.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hinge arrangement between the sash and intermediate frame provides dynamic movement capability, allowing the intermediate frame to rotate approximately 180 degrees from its normal position to a cleaning position. This dynamic configuration enables versatile operation (normal use and cleaning) without requiring multiple fixed structures.

Inventive Principle:
Principle #15Dynamics

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 configuration ensures stable, safe, and balanced operation of the roof window, reducing the risk of accidents and extending the device's lifespan by counterbalancing forces and minimizing wear, while allowing for easy adjustment to accommodate varying roof inclinations.

Implementation Method 1

a spring assembly acts as a force balancing element to the pane-carrying frame by operating on a lifting arm attached to the frame

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a first hinge axis provided by a top hinge arrangement to provide a first operational condition

Methodology Applied
Scientific EffectHinge: Hinge

Implementation Method 3

the lifting arm has a first end rotatably connected with a sledge slidably connected with the primary frame in a sledge guide

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4390029A1Roof window with a lifting device
Publication Date: 2024.06.26 VKR HOLDING AS
  • EP4390029A1 patent drawingFigure 1A
  • EP4390029A1 patent drawingFigure 1B
  • EP4390029A1 patent drawingFigure 1C

AI summary

In the roof window (100), the lifting device (10) further comprises a lifting arm (14) inserted between the primary frame (1) and the at least one secondary frame (2, 3). The lifting arm (14) has a first end (12) rotatably connected with a sledge (30) slidably connected with the primary frame (1) in a sledge guide (16) and a second end (13) rotatably connected with the at least one secondary frame (2, 3). The lifting device (10) further comprises a spring assembly (20) configured to be coupled to the sledge (30). The lifting arm (14) and the sledge guide (16) extend along a length direction (L) defining a central plane (P).