Casement Window Hook Mechanism for Windload Resistance
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Solution Overview
Problem
Window assemblies in coastal regions face challenges in withstanding high windloads during hurricanes or tornadoes, leading to potential permanent deformation and separation of sash frames from main frames, especially when glass panels are broken by impact.
Innovation Solution
A casement window assembly with hook members secured to reinforced vertical frame members of both the sash and main support frames, which engage to prevent deflection and separation under high windloads and provide a snubbing action for compressing resilient seals, ensuring the sash frame remains connected to the main frame even after glass breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sash frame is made movable for opening and closing operation, then the window provides ventilation and opening capability, but the sash frame becomes susceptible to deflection and separation under high windloads
Solution Approach 1:
The hook members are designed to dynamically engage and disengage based on windload conditions. During normal operation, the sash frame can move freely for opening and closing. When high windloads occur, the hooks automatically engage to prevent separation, providing adaptive protection without restricting normal functionality.
Solution Approach 2:
The hook members act as intermediary elements between the sash frame and main frame. These hooks provide a mechanical connection that activates under windload conditions, mediating the force transfer between the movable sash frame and the fixed main frame to prevent separation while allowing normal operation.
2Illumination intensity
If the glass panel unit is used for vision and light transmission, then the window provides transparency and viewing capability, but the glass becomes vulnerable to impact breakage during hurricanes
Solution Approach 1:
The resilient seal is positioned beforehand to engage with the sash frame members, providing cushioning protection. When impact occurs and glass breaks, the seal absorbs and distributes the force, preventing the broken glass and sash frame from separating under windload conditions.
Solution Approach 2:
The design accepts that glass breakage may occur during severe hurricanes but converts this harmful event into a beneficial outcome. The resilient seal is designed to engage and provide protection precisely when the glass breaks, transforming the vulnerable state into a protected state where the seal prevents separation.
3Ease of operation
If the sash frame is designed to move freely for operation, then the window operates smoothly, but the sash frame experiences permanent deformation under high negative windloads
Solution Approach 1:
The hook members provide dynamic support that activates only when needed. During normal operation, the sash frame moves freely without restriction. When high negative windloads cause deflection, the hooks engage to provide rigid support, preventing permanent deformation while maintaining smooth operation under normal conditions.
Solution Approach 2:
The hook members are pre-positioned to engage before permanent deformation occurs. When windloads begin to deflect the sash frame, the hooks automatically engage to counteract the deformation forces, preventing permanent shape change before it can occur.
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 hook members effectively limit deflection and prevent permanent deformation of the sash frame, keeping it connected to the main frame during high windloads and after glass breakage, maintaining structural integrity and ensuring a secure seal.
Implementation Method 1
The hook members may further provide for producing a snubbing action for compressing a resilient seal when the sash frame is moved to its closed position
Data Source
AI summary
A casement window assembly includes a rectangular sash frame enclosing an insulated glass panel unit and supported for swinging movement by a surrounding main window support frame. At least one set of interfitting and interlocking members are positioned in opposing relation on adjacent vertical members of the sash frame and support frame and have hook portions positioned to pass each other when the sash frame is pivoted between a closed position and an open position. The hook portions are effective to engage and hook each other in response to a substantial positive or negative windload or such windload applied after an impact breaks the glass to limit deflection and prevent permanent deformation of the sash frame. The hook portions also produce a snubbing action for compressing a flexible seal between the sash frame and support frame.