Multi-Stage Parachute Reefing for Shock Load Reduction
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Solution Overview
Problem
Parachute deployments often generate dangerous shock loads or snatch loads during the opening of the parachute canopy, posing a safety risk to the occupant.
Innovation Solution
A parachute assembly with multi-stage reefing, comprising a parachute canopy, first and second reefing lines, and cutters that break the reefing lines at predetermined times after triggering events, allowing the canopy to open in stages and reduce shock loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the parachute canopy is deployed quickly to provide rapid deceleration, then the productivity of the parachute deployment is improved, but shock loads are generated that harm the occupant's safety
Solution Approach 1:
The reefing line is divided into multiple segments (first reefing line and second reefing line) that can be broken at different times. The first segment breaks after a first elapsed period to allow initial canopy inflation, then the second segment breaks after a second elapsed period to allow further inflation. This segmentation enables staged deployment that reduces shock loads while maintaining deployment effectiveness.
Solution Approach 2:
The cutters are pre-configured with time-delay mechanisms that automatically break the reefing line segments at predetermined times after the triggering event. The first cutter is set to break the first reefing line after a first elapsed period, and the second cutter is set to break the second reefing line after a second elapsed period. This preliminary setup ensures controlled staged inflation without requiring active control during deployment.
2Area of moving object
If the reefing line is made longer to allow greater canopy inflation, then the area of the parachute canopy is improved, but the time required for deployment is increased
Solution Approach 1:
The reefing line is segmented into multiple sections with different lengths, where the first reefing line has a first length and the second reefing line has a second length. By breaking the segments at different times, the system achieves progressive canopy inflation - initially restricting inflation with the first segment, then allowing further inflation when the second segment breaks. This enables greater total canopy area while controlling deployment timing.
Solution Approach 2:
The effective length of the reefing line is dynamically changed during deployment through the breaking of segments. Before the first cutter activates, the full length of the first reefing line restricts inflation. After the first cutter breaks the first segment, the remaining length allows greater inflation. After the second cutter breaks the second segment, the maximum canopy area is achieved. This dynamic length adjustment optimizes both timing and final canopy size.
Data Source
AI summary
A parachute assembly may comprise a canopy and one or more reefing lines. The one or more reefing lines may limit inflation of the canopy to attenuate impulse load or otherwise mitigate forces exerted by the parachute assembly on cargo or an occupant during deployment of the canopy. The one or more reefing lines may be broken in stages to selectively limit inflation of the canopy followed by selectively permitting inflation of the canopy in stages.