A 3-ring parachute release system. Also called a "3-ring circus", it's used to reliably release a malfunctioning main parachute so that the reserve chute can be safely deployed.
46-second video showing the 3-ring release mechanism in real-time, and again at 1/20th speed:
Awarded patent #4337913 in 1982, to inventor William R. Booth.
More:
https://www.google.com/patents/US4337913
https://en.wikipedia.org/wiki/Malfunction_(parachuting)
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