Stopwatch and elevator: what they have in common

1. Step 1. Stopwatch — has part — Balance wheel. A balance wheel sets the pace.
2. Step 2. Balance wheel — has part — Spring. A spiral hairspring returns the balance.
3. Step 3. Spring — is part of — Elevator safety brake. Springs throw out the catches when the rope goes slack.
4. Step 4. Elevator safety brake — is part of — Elevator. Otis’s safety brakes.

Open Evothings