Adjustable Leg Restraint for Ejection Seat Canopy Clearance
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Solution Overview
Problem
Ejection seats pose a hazard to pilots due to unpredictable canopy fracturing patterns, which can leave canopy fragments over the legs during ejection, potentially causing injury.
Innovation Solution
An adjustable leg restraint system that includes a leg guard and extension flange, which can be translated relative to the side panel of the ejection seat, equipped with a guide flange, stop, and spring-loaded restraint pin, allowing the leg guard to be automatically extended to clear any remaining canopy fragments from the pilot's legs during ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a canopy piercer is used to fracture the canopy, then the canopy can be removed from the path of the ejection seat, but the fracturing pattern is unpredictable and may leave canopy fragments over the pilot's legs
Solution Approach 1:
The leg restraint is pre-positioned in a retracted state within the ejection seat structure. Before ejection occurs, the system is configured so that the leg restraint will automatically extend to its protective position during the ejection sequence, clearing the path before any canopy fragments can reach the pilot's legs.
Solution Approach 2:
The leg restraint acts as an intermediary protective element between the canopy fragments and the pilot's legs. It is positioned to intercept and remove canopy fragments that would otherwise contact the pilot, serving as a mediating safety mechanism between the canopy piercer and the occupant.
2Object-affected harmful factors
If the leg restraint is made adjustable to clear canopy fragments, then pilot safety is improved, but the device complexity increases
Solution Approach 1:
The leg restraint is designed with dynamic adjustability, allowing it to move between a retracted position during normal seating and an extended protective position during ejection. This dynamic capability enables the system to adapt to different operational states without requiring multiple separate components.
Solution Approach 2:
The leg restraint incorporates automatic actuation mechanisms that trigger the extension of the leg restraint based on ejection seat movement or canopy piercer activation. This self-service functionality eliminates the need for manual adjustment or complex control systems, reducing overall device complexity while maintaining safety.
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 adjustable leg restraint effectively removes any remaining canopy fragments from the pilot's path, enhancing safety by ensuring a clear expulsion trajectory and reducing the risk of injury from debris.
Implementation Method 1
a spring configured to apply a biasing force to the extension flange
Data Source
AI summary
An adjustable leg restraint for an ejection seat may be configured to translate between an extended state and a nonextended state. The adjustable leg restraint may include a leg located proximate a side panel of the ejection seat. An extension flange may be coupled to the leg guard. The extension flange may be configured to translate the leg guard relative to the side panel of the ejection seat.