Aircraft Cowling Door Open-Door Locking System
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Solution Overview
Problem
Existing cowling access door open holding systems for aircraft are cumbersome, requiring two-hands operation, taking up significant space, and lacking an automatic latching feature to secure the door in the open position, which hinders maintenance access and can lead to unintended door closure.
Innovation Solution
A cowling assembly with a hinged door and an open-door locking system that includes a hinge bracket with a locking notch and an open-door locking device comprising a sliding block and slider, allowing for single-hand operation, compact design, and automatic latching in the open position, thereby preventing unintended closure during maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas springs and hold open rods are used to secure the cowling access door in the open position, then the door can be held open, but they restrict and hinder maintenance workers' access to the machinery and require significant installation space
Solution Approach 1:
The patent removes the traditional gas springs and hold open rods from the system, extracting the problematic elements that blocked maintenance access. Instead, it introduces a compact locking device with a locking lever and pawl mechanism that achieves the same door holding function without the space-consuming components.
Solution Approach 2:
The locking device automatically engages when the door is opened to a certain angle, with the locking lever and pawl mechanism self-activating without requiring manual intervention. The door's own weight and movement trigger the locking action, eliminating the need for external gas springs or rods.
2Reliability
If gas springs are used to hold the door open, then the door can be secured in the open position, but they do not protect against unintended closing and require maintenance due to aging gaskets
Solution Approach 1:
Instead of using elastic elements like gas springs that rely on maintaining pressure over time, the patent inverts the approach by using a mechanical locking mechanism where the locked position is the stable state. The locking lever with spring-loaded pawl creates a positive mechanical engagement that prevents unintended closing, and the system is designed to be maintenance-free with no aging components.
3Reliability
If hold open rods are used to secure the door, then the door can be held open, but they require two-hands operation and take a lot of space for installation
Solution Approach 1:
The patent combines multiple functions into a single integrated locking device. The locking lever simultaneously performs the functions of holding the door open, preventing unintended closing, and providing a release mechanism. This merged design eliminates the need for separate hold open rods and reduces operational complexity to a simple one-handed lever pull.
4Ease of operation
If folding struts are used to secure the door in the open position, then maintenance workers are not in the way, but they require two-hands operation
Solution Approach 1:
The locking device automatically engages when the door is opened to a certain angle, with the locking lever and pawl mechanism self-activating without requiring manual intervention. This self-service characteristic eliminates the two-hands operation requirement while maintaining maintenance worker accessibility.
Data Source
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AI summary
The present embodiments relate to an assembly with a hinged door pivotally mounted to a carrier element, and a locking system for locking the hinged door in an open position, wherein the locking system comprises a hinge bracket (420) rigidly attached to the carrier element, the hinge bracket comprising a locking notch; and an open-door locking device (210) comprising a mounting bracket (419) pivotally mounted to the hinge bracket; a housing (410) connected to the mounting bracket and rigidly attached to the hinged door; a sliding block (430) slidable in the housing between a normal position and an actuated position; and a slider (470) slidable in the housing between a blocking position and a releasing position, the slider being in the blocking position and engaging the locking notch of the hinge bracket for blocking the hinged door in the open position when the sliding block is in the normal position.