Back in 1974 – when cartridges and disposables were starting to be a thing – Gillette patented a disposable blade unit for traditional razors.

In other words, they invented a new blade for a double edge razors. And by invented, I mean combined the inventions of Georg Friedrich Hofmann and Janos Oscar Plesch.

The main problem the patent was meant to solve? Most likely the problem that customers gave their money to people who wasn’t Gillette. But you can’t write that in a patent, so the abstract is a bit more verbose: