Telescoping Hold Open Rod Assembly for Aircraft Nacelle Panels
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Solution Overview
Problem
Aircraft cowls require a mechanism to securely hold open panels for maintenance access while accommodating both compressive and tensile loads, necessitating a locking system that can be easily operated by a single person and maintain stability under varying loads.
Innovation Solution
A hold open rod assembly with a telescoping locking mechanism, featuring a control shaft, lock pins, and a plunger mechanism that allows for controlled extension and retraction, enabling the rod to sustain compressive loads and self-reset for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is used to hold the cowl open, then the cowl can be retained in an open position, but the mechanism becomes complex and difficult to operate
Solution Approach 1:
The locking mechanism is divided into separate functional components: a hold-open rod for positioning, lock pins for securing, and a plunger mechanism for engagement control. This segmentation allows each component to perform its specific function efficiently, reducing overall complexity while maintaining reliability
Solution Approach 2:
The lock pins are nested within the hold-open rod structure, and the plunger mechanism is integrated into the same assembly. This nested configuration consolidates multiple functions into a compact unit, reducing the number of separate parts and simplifying operation while ensuring secure locking
2Strength
If the rod is designed to accommodate both compressive and tensile loads, then the structure becomes more robust, but the design complexity increases
Solution Approach 1:
The hold-open rod is designed as a multi-functional component that simultaneously handles compressive loads when holding the cowl open and tensile loads during locking engagement. This universal design eliminates the need for separate structural elements, reducing overall complexity while maintaining robust load-bearing capacity
Solution Approach 2:
The rod transitions between different functional states: in an extended position it primarily承受 compressive loads to hold the cowl open, while in a retracted position it withstands tensile loads during locking. This dynamic adaptation allows a single rod design to meet multiple structural requirements without over-engineering
3Reliability
If multiple operators are required to operate the locking mechanism, then the mechanism can be more secure, but the ease of operation decreases
Solution Approach 1:
The plunger mechanism is designed to automatically engage and disengage the lock pins through a simple pushing or pulling motion. The mechanism self-regulates the locking action, requiring minimal operator effort while maintaining secure engagement. The spring-loaded plunger automatically resets after each operation, enabling single-operator use without compromising security
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
Enables a single operator to securely hold open aircraft panels under compressive and tensile loads, facilitating maintenance access while maintaining stability and ease of operation, allowing for efficient panel management and load distribution.
Implementation Method 1
a spring positioned inside the hold open rod assembly and engaged with the plunger to apply an elastic force to the plunger to bias the plunger toward the engaged position
Data Source
Figure 1A~2B
Figure 3A~3C
Figure 4
AI summary
A hold open rod assembly (10) includes an outer tubular structure (14) and an inner tubular structure (12) positioned for telescoping movement relative to the outer tubular structure. A locking mechanism (16) retains the hold open rod assembly in an extended state to support a panel (103, 105) of an aircraft nacelle (102) in an open position at the selection of a user.