Sash Window Lock Cam Self-Alignment
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Solution Overview
Problem
Conventional sash window locks are easily bypassed by burglars and provide inadequate security, often requiring additional and inconvenient reinforcement measures.
Innovation Solution
A handle-operated sash window lock with a cam and sweep arm channel, featuring a semi-circular axle port and elongated-arcuate inner wall, which self-locates and securely engages with a keeper catch, using a resilient tension member for enhanced security and alignment flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional locks are used on sash windows, then the window can be opened and closed, but the security against unauthorized entry is inadequate
Solution Approach 1:
The cam is nested within the housing and rotates within a defined chamber, with the sweep arm extending from the cam body. The keeper is received within the sweep arm's channel, creating a nested arrangement where the locking components are contained within each other, providing security while maintaining a compact structure
Solution Approach 2:
The locking mechanism is divided into distinct functional segments: the handle for operation, the cam for rotational movement, the sweep arm for engagement, and the keeper for anchoring. This segmentation allows each component to perform its specific function efficiently while contributing to overall security
2Reliability
If additional locking devices or reinforcements are added to improve security, then security is enhanced, but the window function is obstructed and convenience is reduced
Solution Approach 1:
The cam serves multiple functions: it provides the primary locking action through rotation, engages the keeper to secure the window, and can be operated from the interior to lock or unlock. This multi-functionality eliminates the need for separate reinforcement devices while maintaining both security and operational convenience
Solution Approach 2:
The sweep arm and cam are combined into a single integrated component, where the sweep arm extends from the cam body. This merging reduces the number of separate parts needed while achieving both security engagement and smooth operation through the rotation mechanism
3Ease of operation
If the cam is made rotatable for locking and unlocking, then the lock can be operated, but it becomes vulnerable to manipulation by thin bladed instruments
Solution Approach 1:
The cam features a curved, cam-shaped profile with a rounded exterior surface that rotates within the housing. This curved geometry provides the necessary rotational movement for locking and unlocking while preventing insertion of flat bladed instruments, as the rounded surface does not provide flat edges for leveraging
Solution Approach 2:
The sweep arm acts as an intermediary between the rotating cam and the keeper. The cam's rotation drives the sweep arm to engage or disengage from the keeper, providing a mechanical advantage that protects the rotation mechanism from direct manipulation while maintaining operational capability
4Ease of manufacture
If the sweep arm channel has a round outer wall, then manufacturing is simpler, but alignment flexibility with the keeper is reduced
Solution Approach 1:
The sweep arm channel features an asymmetric cross-section with a flat outer wall opposite the rounded interior. This asymmetric geometry provides manufacturing simplicity through the rounded portion while the flat exterior surface enables alignment flexibility and proper engagement with the keeper, accommodating variations in installation positioning
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 lock provides robust security by preventing unauthorized access, even when the keeper and housing are misaligned, and can be easily opened with a handle turn, offering a convenient and effective solution for securing sash windows.
Implementation Method 1
A resilient tension member is disposed in the circular-shaped groove and is rotatable by the axle. The tension member includes at least one projection for engaging with the indentation on the wall of the groove when the axle is rotated to a predetermined position.
Data Source
AI summary
A security lock having a housing and a cam. The housing includes an indent with a pair of guide portions. The cam is positioned within the indent and includes an axle port. A shaft of an axle is adapted to be inserted into the axle port so that the cam and the axle are rotatable together. The cam includes a sweep arm and a channel disposed on an upper surface of the sweep arm. The sweep arm has an outer wall that is either elongate-shaped or semicircular-shaped. The channel has a semi-circular-shaped inner wall and an elongate-shaped outer wall. Upon rotation of the axle, the cam rotates about the guide portions into a locked posture in the housing. The elongate-shaped outer wall of the channel allows the security lock to be self-locating when the housing and a keeper are misaligned when installed, respectively, on opposing window sashes.