Integrated Sash Lock and Tilt Latch for Window Security
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Solution Overview
Problem
Existing sash locks and tilt latches for sliding sash windows lack a comprehensive solution for force-entry resistance and safe child-proofing, as they do not effectively prevent unauthorized access or small child egress through the window opening.
Innovation Solution
An integrated sash lock and tilt latch system that includes a forced-entry-resistant mechanism with a spring-biased cam and plate member, and a cooperative interaction with a stop member to limit window travel, ensuring the window cannot be easily opened from the exterior and preventing small child egress by restricting the opening size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional sash lock is used, then the window can be opened easily for authorized access, but it is vulnerable to forced entry from the exterior
Solution Approach 1:
The sash lock employs a dynamic cam mechanism that rotates between locked and unlocked positions. The cam's rotational movement allows the locking surface to engage or disengage from the strike plate, providing both forced-entry resistance when locked and ease of operation when unlocked through simple cam rotation.
Solution Approach 2:
The locking mechanism is segmented into distinct functional components: the cam for primary locking, the plate member for forced-entry resistance, and the spring for maintaining engagement. This segmentation allows each component to specialize in its function while working together to resolve the contradiction between security and ease of use.
2Ease of operation
If the window is made fully openable for cleaning access, then cleaning is easy, but small children can escape through the opening
Solution Approach 1:
The tilt latch mechanism changes the opening parameter from full sash movement to limited tilting motion. The latch member engages with the sash at a specific point, allowing the window to tilt inward at a controlled angle that provides cleaning access while maintaining an opening size too small for child egress.
Solution Approach 2:
The tilt latch prevents the harmful effect of child egress by preliminarily constraining the window's degree of rotation. The latch member's engagement point and geometry are designed to allow necessary tilting for cleaning while automatically preventing excessive opening that would enable child escape.
3Reliability
If a spring-biased plate member is added to prevent forced entry, then security is improved, but the device complexity increases
Solution Approach 1:
The spring-biased plate member is self-actuating through cam rotation. As the cam rotates during normal locking operations, it automatically drives the plate member into engagement with the strike plate or releases it, eliminating the need for separate actuators or complex control systems while maintaining forced-entry resistance.
Solution Approach 2:
The plate member mechanism is merged with the existing cam-based locking system. The cam's rotational path is designed to simultaneously engage the keeper and drive the plate member, combining multiple security functions into a single integrated mechanism that reduces overall complexity.
4Adaptability or versatility
If the sash lock and tilt latch are integrated through a single cam, then cooperative operation is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The single cam is designed as a universal driver that performs multiple functions: it rotates to lock/unlock the sash, drives the plate member for forced-entry resistance, and actuates the tilt latch mechanism. This multi-functionality is achieved through carefully designed cam surfaces that engage different components at different rotation positions, reducing the need for multiple separate actuators.
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 system provides enhanced security by preventing forced entry and ensuring the window cannot be opened wide enough for a small child to pass through, while maintaining ease of use for authorized access and cleaning.
Implementation Method 1
a spring-biased plate member that selectively interacts with the cam
Data Source
AI summary
A window fastener includes a forced-entry-resistant sash lock and tilt latch assembly. The sash lock is actuated to engage a keeper to lock the closed sash window. The tilt latch assembly permits sliding of the unlocked window, and prevents tilting until the tilt latch assembly is actuated by the interconnected sash lock. The sash lock and tilt latch assembly cooperate with a stop member secured to a master window frame, to limit opening of the window to a position between the closed position and a full open position, through contact of the latch assembly with a portion of the stop member. The sash lock is configured to actuate the latch assembly into a cocked position, permitting window movement beyond the limited position, and selective contact between the latch assembly and stop member that triggers latch assembly repositioning, causing automatic locking of the sash window when moved into the closed position.