Canopy Piercer for Ejection Seat Arm Restraint Deployment
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Solution Overview
Problem
Current ejection seat arm restraint systems face damage and improper positioning due to insufficient canopy fracture patterns, which fail to accommodate the deployment of arm restraints through the aircraft canopy without contacting unfractured material, leading to potential injury and system failure.
Innovation Solution
An arm restraint assembly with a canopy piercer mechanism that deploys prior to ejection, allowing the arm restraint to pivot and position correctly by fracturing the canopy, reducing resistance and ensuring proper deployment and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the canopy fracture pattern is made larger to allow arm restraint deployment, then the arm restraint system can pass through without contacting unfractured canopy material, but the structural integrity of the canopy is compromised
Solution Approach 1:
The canopy piercer is deployed before the arm restraint system to pre-fracture the canopy material along a predetermined path. This preliminary action creates a controlled fracture pattern that guides subsequent arm restraint deployment, ensuring the restraint passes through weakened material rather than forcing through intact canopy structure.
Solution Approach 2:
The canopy fracture is segmented into a specific pattern with distinct zones: a first portion for arm restraint passage and a second portion that maintains structural support. This segmentation allows different regions of the canopy to serve different functions - one area compromised for deployment while another retains integrity for structural support.
2Strength
If the canopy fracture pattern is made smaller to maintain structural integrity, then the canopy strength is preserved, but the arm restraint system contacts unfractured canopy material causing damage or improper positioning
Solution Approach 1:
The fracture pattern is designed with localized quality variations - a first portion with reduced structural integrity for arm restraint passage and a second portion maintaining full strength for structural support. This local differentiation allows the canopy to be weak where needed for deployment while remaining strong where needed for structural integrity.
3Device complexity
If the arm restraint system is deployed before canopy fracture, then the deployment sequence is simplified, but the arm restraint contacts unfractured canopy material causing damage
Solution Approach 1:
The canopy piercer performs the fracture action before the arm restraint deployment, establishing a prepared path through the canopy. This preliminary fracturing ensures that when the arm restraint is deployed, it encounters pre-weakened material rather than intact canopy structure, preventing contact damage.
Solution Approach 2:
The canopy piercer acts as an intermediary device that prepares the canopy structure for subsequent arm restraint deployment. By first creating the fracture pattern and then allowing the arm restraint to follow this prepared path, the piercer mediates between the intact canopy and the deploying restraint system.
Data Source
AI summary
An arm restraint assembly configured to pierce a canopy in response to expulsion of an ejection seat from a cockpit may comprise a primary arm configured to pivot relative to the ejection seat. A canopy piercer may be coupled to the primary arm. The primary arm may be configured to rotate to a fully-deployed position while located within the cockpit. An apex of the canopy piercer may be oriented toward the canopy, when the primary arm is in the fully-deployed position.