Composite Hold-Open Rod Sleeve for Wear and Heat Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The hold open rods in aircraft cowling systems experience wear and thermal damage due to vibrations when secured in place by spring clips during aircraft operation, as they are subjected to continuous stress and heat application.
Innovation Solution
A tubular rod body made of composite material with a localized sleeve and a thermally resistant bushing, secured by heat application, which absorbs thermal energy and reduces wear through cushioning and damping, and a spring clip that retains the rod in a stowed position, using materials like polyolefin and PEEK for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hold open rod is secured in place by a spring clip during aircraft operation, then the rod is retained in a stowed position, but the rod experiences vibration-induced wear at the spring clip location
Solution Approach 1:
The patent applies a localized sleeve made of wear-resistant material (such as PTFE or UHMWPE) specifically at the region where the spring clip contacts the rod body. This localized application provides enhanced wear resistance at the critical contact point without requiring the entire rod to be made of wear-resistant material, thus resolving the contradiction between ease of retention and wear resistance.
Solution Approach 2:
The patent employs composite construction by combining the rod body material with a different wear-resistant sleeve material. The sleeve is made from materials such as PTFE, UHMWPE, or other low-friction materials that are bonded or mechanically attached to the rod body. This composite approach allows the rod to benefit from both the structural properties of the rod body material and the wear-resistant properties of the sleeve material at the critical contact location.
2Strength
If heat is applied to secure the sleeve to the rod body, then the sleeve is firmly attached, but the composite rod body may be damaged by thermal energy
Solution Approach 1:
The patent introduces an intermediary layer or method between the heat source and the rod body to protect it from thermal damage. This could involve using a heat-resistant barrier, controlling the heating process to limit thermal exposure, or employing a bonding method that requires minimal heat. The intermediary protects the composite rod body from direct thermal exposure while still allowing the sleeve to be securely attached.
Solution Approach 2:
The patent modifies the heating parameters (temperature, duration, distribution) to achieve sufficient sleeve attachment without exceeding the thermal tolerance of the composite rod body. By carefully controlling these parameters, the process achieves adequate bonding strength while preventing thermal degradation of the rod body materials.
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 solution effectively prevents wear and thermal damage to the composite rod body, maintaining its integrity and functionality while allowing for easy installation and retention of the hold open rod, thereby enhancing the durability and reliability of the cowling system.
Implementation Method 1
A bushing is located radially between the rod body and the sleeve. The bushing is configured to absorb thermal energy of the application of heat.
Implementation Method 2
The sleeve is secured to the rod body by application of heat to the sleeve material.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A rod assembly includes a tubular rod body (52) formed from a composite material and a localized sleeve (54) installed to the rod body. The sleeve is secured to the rod body by application of heat to the sleeve material. A bushing (56) is located radially between the rod body and the sleeve. The bushing is configured to absorb thermal energy of the application of heat. A door and hold open rod assembly of an aircraft includes a door, and a hold open rod (22) assembly secured to the door. The hold open rod assembly is configured to support the door in an opened position when the hold open rod is deployed. The hold open rod assembly includes a tubular rod body formed from a composite material, and a localized sleeve installed to the rod body. A bushing is located radially between the rod body and the sleeve.