They didn't design it to be loud, they designed it to be reliable, less expensive to manufacture and to have excellent typing feel. The basic design was patente

They didn't design it to be loud, they designed it to be reliable, less expensive to manufacture and to have excellent typing feel. The basic design was patented in 1971 and later variant in 1977. It's important for touch typing to have a good hysteresis between make and break and to have a uniform and progressive pressure building up to break-point. Some sound is also helpful. Far from being loud, it would have been quieter than a room full of typewriters, let alone line printers. https://sharktastica.co.uk/wiki?id=ibmbucklingspring https://sharktastica.co.uk/wiki?id=ibmbucklingspring https://patents.google.com/patent/US3699296A/en https://patents.google.com/patent/US3699296A/en https://patents.google.com/patent/US4118611A/en https://patents.google.com/patent/US4118611A/en All that being said, I use a keyboard with cherry green switches and they're OK. It's not got quite as nice of a hysteresis curve, but you can see from the diagrams in the links above why that buckling spring is just a really clever way to make a very nice feel.