Aircraft Cowl Locking System Hinge Reduction
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Solution Overview
Problem
Conventional cowl locking systems for aircraft engine nacelles require multiple gooseneck hinges, which increase bulkiness and weight due to the distance between the cowl's exterior shape and the axis of rotation, compromising the aerodynamic efficiency and mass distribution.
Innovation Solution
A locking system comprising a first hook that moves translationally on the cowl and a second hook mounted on a handle, with a transmission system that allows the hooks to switch between locked and unlocked positions, reducing the number of hinges needed and optimizing their placement closer to the cowl's aerodynamic shape, using a cable and bellcrank mechanism for actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple gooseneck hinges are used to lock the cowl, then the locking reliability is improved, but the bulkiness and weight of the system increase due to the distance between the cowl's exterior shape and the axis of rotation
Solution Approach 1:
The patent extracts the locking function from the traditional gooseneck hinge mechanism. Instead of using multiple bulky goosenecks distributed along the cowl length, the invention uses a single gooseneck hinge combined with a locking system that includes a lock, a handle, and a transmission system. This extraction eliminates unnecessary components while maintaining locking reliability.
Solution Approach 2:
The patent merges multiple functions into a integrated system. The lock, handle, and transmission system work together as a unified mechanism to achieve both locking and positioning functions. The transmission system connects the handle actuation to the lock mechanism, combining actuation and locking functions in one system rather than requiring separate mechanisms.
2Strength
If multiple goosenecks are distributed along the cowl length to react operating loads, then the structural strength is improved, but the alignment requirements increase and bulkiness increases when spaced away from the exterior shape
Solution Approach 1:
The patent extracts the load-bearing function from multiple distributed goosenecks and concentrates it in a single gooseneck hinge positioned at the optimal location. The locking system compensates for the reduced number of hinges by providing mechanical advantage through the lock and transmission mechanisms, maintaining structural strength while simplifying the hinge arrangement.
Solution Approach 2:
The single gooseneck hinge in the invention serves multiple functions: it provides the articulation point for the cowl, acts as a structural support element, and serves as the anchor for the locking mechanism. This multi-functionality replaces the need for multiple specialized components distributed along the cowl.
3Shape
If the goosenecks are positioned closer to the aerodynamic shape of the cowl, then the aerodynamic efficiency is improved, but the locking mechanism becomes more complex to maintain reliability
Solution Approach 1:
The patent merges the locking function with the hinge positioning. By integrating the lock, handle, and transmission system with the single gooseneck hinge, the invention creates a compact assembly that can be positioned close to the aerodynamic shape without requiring complex distributed hinge arrangements. The integrated design simplifies the overall mechanism while maintaining reliability.
Data Source
AI summary
A locking system for locking a cowl to a fixed structure including first and second parts, the first part including a first hook moveable on the cowl and a first shaft fixed to the fixed structure in which the first hook is moveable between locked and unlocked positions, in which the second part includes a handle actuateable between closed and open positions, a second hook and a second shaft fixed to the fixed structure or to another cowl symmetric with the cowl, in which the second hook is moveable between locked and unlocked positions and in which the second hook is mounted where passage of the handle from the closed to open positions causes the second hook to pass from the locked into the unlocked position and vice versa, and in which the locking system also includes a transmission system to move the first hook from the locked into the unlocked position when the handle passes from the closed into the open position, and vice versa.