Sash Lock and Tilt Latch with Vent Stop Mechanism
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Solution Overview
Problem
Existing window hardware for sliding sash windows lacks an integrated solution that effectively prevents sliding and tilting while allowing for controlled ventilation and secure operation, particularly in preventing egress by small children or intruders.
Innovation Solution
An integrated sash lock and tilt latch fastener system that uses a single cam mechanism to lock and unlock the window, featuring a detent mechanism for secure engagement and disengagement, with a stepped stop to limit window travel and prevent tilting, allowing for controlled sliding and ventilation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sash lock is used to prevent sliding movement of the window, then security against intruders is improved, but the window cannot be opened for ventilation or cleaning
Solution Approach 1:
The lock system transitions between different states (locked, unlocked, tilted) to provide both security and ventilation access. The sash lock engages to prevent sliding when security is needed, and disengages to allow the window to be tilted open for ventilation or cleaning, making the system dynamically adaptable to different operational requirements.
Solution Approach 2:
The window opening function is segmented into two independent movements: sliding (prevented by sash lock for security) and tilting (enabled by tilt latch for ventilation). This segmentation allows the window to provide ventilation access without compromising security against forced entry through sliding.
2Ease of operation
If a tilt latch is used to permit pivoting of the window for cleaning, then maintenance access is improved, but the window may be pried open creating security vulnerabilities
Solution Approach 1:
The tilt latch provides dynamic control over window positioning, allowing the window to be tilted to various angles for cleaning access while maintaining the ability to return to a locked position. The latch engages with a keeper to secure the tilted position during maintenance, then disengages to allow the window to be returned to its secure closed position.
Solution Approach 2:
The tilt latch acts as an intermediary mechanism between the window sash and the frame, providing controlled pivoting motion. It mediates the conflict between needing access for cleaning and maintaining security by allowing temporary, controlled opening while preventing unauthorized forced entry.
3Productivity
If the window is allowed to open fully for ventilation, then air flow is improved, but small children can escape or intruders can enter
Solution Approach 1:
The vent stop creates a dynamic limitation on window travel, allowing the window to be tilted open to a controlled angle that provides adequate ventilation airflow while preventing full opening. This dynamic stop mechanism ensures children cannot escape while maintaining effective ventilation through the limited opening.
Solution Approach 2:
The vent stop structure预先 (in advance) prevents the window from opening beyond a safe angle. By providing a physical barrier before the window can reach a position that would allow child egress, the system proactively eliminates the harmful effect while preserving the beneficial ventilation function.
Data Source
AI summary
A sash window fastener includes: a latch assembly; a sash lock assembly mounted upon the meeting rail; and a stop member mounted to the master window frame. The lock assembly includes a pivotable cam to engage a keeper on the master frame to lock the window, and a pivotable follower arm. The arm interconnects with the latch assembly within the meeting rail, so cam rotation that drives arm rotation also causes translation of the latch. The cam may occupy: an extended position to secure the cam to the keeper, with the latch engaging the master frame to prevent tilting, and being positioned below a protrusion on the stop member to redundantly lock the window; a first retracted cam position permitting sliding of the window; and a second retracted position permitting tilting of the sash window. Additional protrusions may be used on the stop member to serve as vent stop positions.