柏林鑰匙

Daily Hacker News 上看到「Berlin key」這個東西,用機械結構就可以強迫使用者一定要鎖門的鑰匙。

門平常都是上鎖的,要解鎖要先用鑰匙打開,然後從另外一邊鎖上後才能拿出來:

是個有年代的設計,但現在在柏林還是有不少這樣的設計:

Invented by the Berliner locksmith Johannes Schweiger, the Berlin key was massively produced by the Albert Kerfin & Co company starting in 1912. With the advent of more recent locking technologies, this kind of lock and key is becoming less common. It was estimated that 8000-10000 are still in use today in Berlin, Germany.

現代則是用自動門的門禁來管制,但這個設計還是很有趣...