The worm-gear lock
Inventors (Intermediate), mission I3 Gear Superpowers, lesson 4 of 6.
Hook
This gear has a superpower no other gear has: it never lets go.
Fair test
Lift a 50 g load. Let go of the handle. Does it drop? Count handle turns per 10 cm.
Bonus challenge
Try to turn the gear backwards from the load side. Impossible?
The build
🏗️ Worm-Gear Crane: Crank the worm gear to lift the boom — then let go. It stays up by itself! (level 3 of 5, about 30 minutes, 15 steps)