Aircraft Propulsion Latch Assembly With Rack-and-Pinion Cowl Retention
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Solution Overview
Problem
Existing latch assemblies for aircraft propulsion systems are in need of improvement to enhance security and ease of operation, particularly in securing movable cowl panels during flight.
Innovation Solution
A latch assembly with a hook and retention assembly featuring a semi-annular stopper, rack, and pinion gear mechanism that allows for secure engagement and disengagement of cowl panels, utilizing a pivotable stopper and translatable rack to maintain panel integrity and facilitate access as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a latch assembly is designed to provide strong retention and security for cowl panels, then reliability is improved, but device complexity increases
Solution Approach 1:
The latch assembly is divided into distinct functional components: a hook portion with engagement surface, a stopper member with gear surface, a pinion gear, and a rack member. Each component has a specific function, allowing the complex retention mechanism to be built from simpler, interchangeable parts that can be manufactured and maintained more easily
Solution Approach 2:
The pinion gear is disposed within the hook body, and the rack member translates within a slot in the hook body. The stopper member pivots within the hook. This nested arrangement compactly packages multiple moving parts within the latch assembly structure, reducing overall complexity while maintaining the required security function
2Reliability
If a latch assembly uses a complex retention mechanism to prevent unintended separation, then reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The stopper member is made pivotable about the pin axis, and the rack member is made translatable along the slot. This dynamic design allows the retention mechanism to easily transition between locked and unlocked states through simple linear motion of the rack, making operation easy while maintaining strong retention when engaged
Solution Approach 2:
The manual latch operation is replaced by an automated actuation system using a motor and drive mechanism that rotates the pinion gear. This substitutes complex manual manipulation with a simple electrical control system, improving ease of operation while maintaining reliable engagement through the mechanical gear interaction
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 mechanism provides enhanced security by preventing unintended separation of cowl panels while allowing easy access for maintenance, improving operational efficiency and safety.
Implementation Method 1
The pinion gear includes a pinion gear surface. The pinion gear surface is engaged with the stopper gear surface and the linear rack gear surface.
Implementation Method 2
The retention assembly may further include a biasing member disposed within the slot. The biasing member may be disposed between the hook body and the rack to bias the rack in the second translation position.
Data Source
AI summary
A latch assembly includes a first latch assembly portion. The first latch assembly portion includes a hook. The hook includes a hook body and a retention assembly. The hook body forms a hook engagement surface. The hook engagement surface extends about a pin axis. The hook body forms a groove at the hook engagement surface. The groove extends about the pin axis. The hook body forms a slot at the outer body side. The retention assembly includes a stopper, a rack, and a pinion gear. The stopper is disposed within the groove. The stopper extends about the pin axis between and to a first end and a second end. The stopper includes an outer radial surface and an inner radial surface. The stopper includes a stopper gear surface at the outer radial surface. The inner radial surface is disposed at the hook engagement surface. The stopper is pivotable in the groove about the pin axis. The rack is disposed within the slot. The rack extends between and to an outer rack side and an inner rack side. The rack includes a linear rack gear surface at the inner rack side. The rack is translatable within the slot. The pinion gear is disposed within the hook body. The pinion gear is rotatable about a rotational axis. The pinion gear includes a pinion gear surface. The pinion gear surface is engaged with the stopper gear surface and the linear rack gear surface.