Movable Spring Housing Window Counterbalance for Egress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing counterbalance systems in tilt-in windows restrict the maximum opening size due to stored springs, necessitating oversized windows to meet safety codes, which increases the risk of children falling out, and aftermarket safety bars hinder fire escape and cleaning.
Innovation Solution
A counterbalance system with a free-moving spring housing and brake shoe that allows greater window opening by preventing the spring housing from descending below a wedge stop, enabling the brake shoe to rise and provide increased access while engaging localized resistance at safe-open positions to prevent child access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spring housing is fixed in position to store counterbalance springs, then the counterbalance system can maintain window sash position, but the maximum opening size is restricted due to space occupied by stored springs
Solution Approach 1:
The spring housing is made movable along the guide track instead of being fixed, allowing it to dynamically adjust position based on window sash orientation. When the sash is open, the housing moves to a retracted position clear of the opening path, maximizing the accessible opening size while still providing counterbalance function when needed.
2Length of moving object
If oversized windows are used to meet safety code requirements for access opening, then sufficient fire escape opening is achieved, but the risk of children falling out increases
Solution Approach 1:
The system changes the spatial parameter of the spring housing position dynamically. By retracting the housing when the window is open, the effective opening size is maximized without requiring physically larger window frames, thereby reducing the fall hazard while maintaining code-compliant access openings.
3Object-affected harmful factors
If aftermarket safety bars are installed to prevent child access, then child safety is improved, but fire escape and window cleaning are hindered
Solution Approach 1:
The counterbalance system provides inherent safety functionality through its design. The movable spring housing and brake shoe mechanism create natural resistance at certain opening positions, providing passive safety without requiring additional active components like safety bars that would impede emergency egress.
4Object-affected harmful factors
If the brake shoe is positioned to engage the guide track at safe-open positions, then child access is prevented, but the window opening size is restricted
Solution Approach 1:
The brake shoe engagement position is dynamically adjusted based on window opening state. At normal ventilation positions, the brake shoe engages to provide safety resistance. When the window is fully opened for fire escape, the movable spring housing retracts, allowing the brake shoe to clear the guide track and permitting full opening without restriction.
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 a larger access opening without requiring oversized windows, ensuring unobstructed fire escape while preventing accidental child openings, and maintaining reliable operation with reduced risk of brake shoe binding.
Implementation Method 1
Coil springs are constant force coil springs that supply the counterbalance force to the weight of the window sash
Implementation Method 2
The shoes contain a brake mechanism that is activated by the tilt post of the window sash when the window sash is tilted inwardly away from the window frame
Data Source
AI summary
A counterbalance system for a window assembly having a window sash that moves in a guide track. The counterbalance system has a first stop mounted in the guide track. A spring housing is placed in the guide track above the first stop. The spring housing holds the counterbalance spring that provides the counterbalance force. The spring housing is free to move along the guide track above the first stop. The spring housing is incapable of passing the first stop and traveling below the first stop. A brake shoe is positioned in the guide track. The counterbalance spring has a free end that extends from the spring housing to the brake shoe. The brake shoe is capable of moving in the guide track past the first stop. In this manner, the brake shoe can be raised above the first stop.