Cam Locking Device for Inward-Opening Door Sealing
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Solution Overview
Problem
Inward-opening doors face challenges in resisting wind and hydrostatic forces due to the inherent weakness in locking and sealing mechanisms, which can lead to catastrophic failure, especially when the forces required to operate the locks exceed user capabilities and damage soft seals or hinges.
Innovation Solution
A leaf assembly with a cam locking device that is pivotally mounted and features a cam with a perpendicular plane of rotation, engaging with a cam surface to enhance locking and sealing, allowing the cam to rotate into a locked position when the door is pushed, providing improved resistance and sealing without raising the threshold, and incorporating a biasing mechanism and actuating means for remote operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adjustable locks are tightened to provide good compression against opening forces, then sealing performance is improved, but the forces required to operate the locks exceed user capabilities and may damage seals or hinges
Solution Approach 1:
The cam mechanism inverts the traditional locking approach by using the opening force itself to enhance locking compression. When the door is pushed against the cam in the locked position, the cam surface geometry converts this opening force into increased sealing pressure, rather than requiring separate high-force tightening operations.
Solution Approach 2:
The cam surface geometry is designed with specific arcuate profiles that change the mechanical advantage dynamically. As the cam rotates into the locked position, the contact angle and leverage ratio change to provide optimal sealing pressure while maintaining easy operation through the handle.
2Ease of operation
If the cam plane of rotation is perpendicular to the leaf plane, then the cam can rotate into locked position under pushing force, but the structural complexity of the mounting mechanism increases
Solution Approach 1:
The carrier recess serves multiple functions: it houses the cam mechanism, provides the sealing surface, and guides the cam rotation. This multi-functional design reduces overall structural complexity despite the perpendicular cam orientation, as a single integrated component accomplishes what would otherwise require multiple separate elements.
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 cam locking device enhances locking compression and sealing performance, preventing fluid, air-borne particles, and pressure ingress, while allowing easy user operation and maintaining a level threshold, thus improving door security and usability.
Implementation Method 1
the cam surface having an arcuate profile, and wherein the device is adapted such that when the or each cam is in the locked condition, the exertion of a leaf opening force on the trailing face of the leaf urges the cam to rotate in the direction of the locked condition
Data Source
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AI summary
A locking device for a leaf pivotally mounted in a frame, the leaf having a leading face, a trailing face, a bottom edge and side edges, and being pivotally moveable relative to the frame between an open position and a closed position, the locking device comprising at least a first cam rotatable between an unlocked condition and a locked condition, the plane of rotation of the cam being perpendicular to the plane of the leaf when in the closed position, wherein in the locked condition the cam is engageable with a cam engaging surface on the leaf or the frame, engagement of the cam with the cam engaging surface preventing the leaf from moving away from the closed position.