Bi-Directional Sash Lock with Asymmetric Actuator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sash locks for double-hung window assemblies do not provide a secure locking mechanism that can be easily operated from the inside and offers clear indication of the sashes' unlocked status, while maintaining a compact and aesthetically appealing design.
Innovation Solution
A sash lock system featuring a housing with an actuator arm and cam that can be rotated clockwise or counter-clockwise to engage with a keeper or recess, ensuring secure locking and easy operation, with a non-circular shaft and hole configuration to prevent slippage and a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional sash lock mechanism is used, then the locking function is provided, but the locking mechanism is not secure against external opening attempts and lacks clear indication of unlocked status
Solution Approach 1:
The actuator arm features asymmetric geometry with a non-circular cross-section that includes a flat portion and a curved portion. This asymmetric design prevents the actuator arm from being rotated in both directions freely, allowing operation only from the interior side while providing clear visual indication of the unlocked position through the alignment of the flat portion with the housing aperture
Solution Approach 2:
The cam acts as an intermediary element between the actuator arm and the locking system. When the actuator arm rotates, it drives the cam to rotate and engage with either the keeper or the recess in the lower rail, translating the simple rotational motion of the actuator into the complex locking/unlocking action
2Reliability
If a sash lock with bi-directional engagement capability is designed, then secure locking in both directions is achieved, but the device complexity increases
Solution Approach 1:
The cam is designed with a specialized profile that enables it to perform multiple functions: it can engage with the keeper when rotated in one direction and engage with the recess in the lower rail when rotated in the opposite direction. This single cam component replaces what would otherwise require separate locking mechanisms for each direction, reducing overall device complexity while achieving bi-directional secure locking
Solution Approach 2:
The locking system utilizes dynamic engagement where the cam profile is designed to naturally transition between different engagement states. The cam's asymmetric profile allows it to sequentially engage with either the keeper or the recess based on the rotation direction, creating a dynamic locking system that adapts to bidirectional operation without requiring complex mechanical switches or additional components
Data Source
AI summary
A sash lock for a sash window assembly is disclosed. The sash window assembly includes an upper sash window and a lower sash window. Each of the sash windows is mounted within opposed guide rails on a master frame. At least one of the sash windows is slidable within the frame relative to the other sash window. The sash lock comprises either a keeper, with a keeper opening, for mounting on a rail of one of the sash windows or a recess in the lower rail of the upper sash. The sash lock disclosed herein includes a housing having a hole, an actuator arm, and a cam having a cam element for receipt into the keeper opening or the recess. The locking assembly also includes a shaft extending through the housing hole and operably coupling the actuator arm to the cam.