Saturday, April 29, 2017

[zjutseyk] Padlock logic

A bunch of padlocks on a hasp with multiple holes functions like an AND gate: all locks must be unlocked in order for the hasp to open.  This is seen in safety lockouts.

A bunch of padlocks linked in a chain functions like an OR gate: at least one of the padlocks must be opened to break the chain.  There remains the mechanical or geometric problem of securing something (like a door) with this chain of locks.  A pin can be substituted for a padlock, and the pin can have a hole on each end, each which can take a padlock or another pin.  Other specialized hardware exists, used for granting many different parties access to land.

One can construct complicated graphs of AND and OR locks, though again there may be mechanical difficulties of fitting a padlock to connect desired nodes.  Perhaps not so bad with lengths of chain where necessary.

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