Arresting Cable Retraction Mechanism for Aircraft Runways
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Solution Overview
Problem
Current arresting cable retraction mechanisms are not designed to withstand high-speed aircraft rollover events, leading to frequent maintenance and potential damage to the motion actuator and retraction components.
Innovation Solution
The system decouples the motion actuator used for retraction from components associated with rollover deflection by employing a dual-axis rotation mechanism, where the cable support block assembly rotates about one axis during rollover and another axis during retraction, isolating the actuator from dynamic loading and maintaining the cable above the runway surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motion actuator is integrated with the cable support block assembly to enable retraction, then the retraction function is achieved, but the actuator is exposed to high-speed rollover forces causing damage and frequent maintenance
Solution Approach 1:
The system is divided into two functional segments: a support arm assembly that handles rollover forces and a cable support block assembly that handles retraction. The lock mechanism couples these segments during normal operation but allows them to decouple during rollover events, isolating the motion actuator from harmful forces
Solution Approach 2:
The lock mechanism acts as an intermediary between the support arm assembly and cable support block assembly. It transmits forces during normal operation but can disengage to prevent force transmission during rollover, protecting the actuator while maintaining functional integration
2Reliability
If a single axis of rotation is used for both retraction and rollover deflection, then the device complexity is reduced, but the actuator cannot withstand high-speed rollovers
Solution Approach 1:
The system introduces a second degree of freedom by adding a second axis of rotation. The first axis (at the support block) handles retraction movements while the second axis (at the support arm) handles rollover deflection, allowing independent optimization of each function without increasing overall system complexity
3Reliability
If the cable support block assembly is rigidly connected to the support arm assembly, then structural strength is improved, but the actuator experiences high-speed rollover loading
Solution Approach 1:
The connection between the support arm assembly and cable support block assembly transitions from a static rigid connection to a dynamic conditional connection. The lock mechanism provides rigid coupling during normal operation for structural strength but enables dynamic decoupling during rollover events to protect the actuator, adapting the connection state based on operational conditions
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
This design enhances the system's ability to withstand high-speed rollovers, reducing maintenance needs and ensuring the cable remains above the runway for safe aircraft engagement, thereby extending the life of the motion actuator and the entire system.
Implementation Method 1
a first axis of rotation about which the support arm assembly is configured to rotate during an aircraft rollover event
Implementation Method 2
a second axis of rotation about which the cable support block assembly is configured to rotate during a retraction event
Data Source
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AI summary
An arresting cable retraction mechanism for use across an aircraft runway. The retraction mechanism functions to extend a cable across a runway (for capture by a tailhook of an aircraft) without causing the cable to recede below the runway surface during an aircraft rollover/deflection event. The arresting cable retraction mechanism is also designed to help prevent damage to a retraction motion actuator due to high speed aircraft rollover. The disclosed system separates components related to retraction vs. deflection due to rollover, such that rollover events do not affect or load the motion actuator used for retraction.