Dual-Locking Carrier for Tilt Sash Window Balance Stability
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Solution Overview
Problem
Existing window balance systems lack an effective locking mechanism that securely locks the carrier in the jamb channel, particularly when the window sash is tilted, leading to potential movement and instability.
Innovation Solution
A window balance assembly with a clamshell-type housing and a receiver that engages cam followers to lock the carrier in place, utilizing a dual locking mechanism that expands in both axial and lateral directions to contact multiple surfaces of the jamb channel, enhancing friction and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is added to secure the carrier in the jamb channel, then reliability is improved, but device complexity increases
Solution Approach 1:
The locking mechanism dynamically transitions between locked and unlocked states through rotation of the receiver. The cam surfaces on the receiver engage with cam followers in the housing portions, automatically locking the carrier when the sash is tilted and unlocking when vertical. This dynamic operation provides reliable locking without requiring complex manual intervention or additional control systems.
Solution Approach 2:
The locking mechanism is self-actuating through the rotation of the receiver when the sash is tilted. The cam surfaces automatically engage the cam followers, forcing the housing portions apart to lock the carrier in the jamb channel. The system uses the motion of the sash itself to activate the locking function, eliminating the need for separate actuators or control mechanisms.
2Stability of the object's composition
If a dual locking mechanism expanding in axial and lateral directions is used, then stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The locking mechanism transitions from a single-dimensional lock to a dual-dimensional lock by expanding the carrier in both axial and lateral directions. The cam surfaces on the receiver engage cam followers that force the housing portions apart simultaneously in multiple directions, creating contact with front and back surfaces as well as opposing side surfaces of the jamb channel. This multi-directional engagement provides enhanced stability without requiring extremely tight tolerances.
Solution Approach 2:
The carrier is divided into opposing housing portions (first and second housing portions) that can move independently relative to each other. Each housing portion has its own cam follower that engages with the cam surfaces on the receiver. This segmentation allows the locking force to be distributed across multiple contact points, improving stability while reducing the precision requirements for any single engagement point.
3Ease of operation
If cam surfaces are used to engage cam followers, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The cam mechanism is self-actuating through the rotation of the receiver when the sash is tilted. The cam surfaces automatically engage the cam followers, forcing the housing portions apart to lock the carrier. The system uses the inherent motion of the sash to activate the locking function, eliminating the need for separate actuators, buttons, or control mechanisms, thereby maintaining ease of operation.
Solution Approach 2:
The cam surfaces on the receiver act as intermediaries that translate the rotational motion of the receiver into the linear separation of the housing portions. This intermediary mechanism provides a simple yet effective way to convert the tilting motion into a locking action, improving ease of operation without requiring complex direct linkage or control systems.
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 solution provides a secure locking mechanism that prevents movement of the carrier in the channel, ensuring stability and ease of maintenance by distributing locking forces effectively across multiple surfaces, improving the overall functionality of the window balance system.
Implementation Method 1
The receiver incorporates cams that engage cam follower surfaces in the housing to improve the distribution of the locking forces of the carrier in the jamb channel
Implementation Method 2
a pair of constant force curl springs having curled convolutions carried by sash shoes
Implementation Method 3
A dual locking carrier expands in both the axial and lateral directions to contact both front and back surfaces and opposing side surfaces of the jamb channel
Data Source
AI summary
A window balance assembly comprising an improved locking carrier mechanism is disclosed. The locking mechanism is actuated when the window sash is tilted. Cam surfaces on the receiver of the mechanism engage cam followers in the clamshell-type housing of the carrier forcing them apart outwardly to lock the carrier in the jamb channel of a window assembly and prevent movement of the carrier in the channel. The receiver incorporates two cams that engage two cam follower surfaces in the housing to improve the distribution of the locking forces of the carrier in the jamb channel. A dual-locking carrier expands in both the axial and lateral directions to contact both front and back surfaces and opposing side surfaces of the jamb channel.