Editing Combination lock (section)

===Single-dial locks===
The [[rotary combination lock]]s found on [[padlock]]s, lockers, or [[safe]]s may use a single dial which interacts with several parallel discs or ''cams''. Customarily, a lock of this type is opened by rotating the dial clockwise to the first numeral, counterclockwise to the second, and so on in an alternating fashion until the last numeral is reached. The cams typically have an indentation or notch, and when the correct [[permutation]] is entered, the notches align, allowing the latch to fit into them and open the lock.

The C. L. Gougler Keyless Locks Company manufactured locks for which the combination was a set number of audible clicks to the left and right, allowing them to be unlocked in darkness or by the vision-impaired.{{citation needed|date=July 2021}}

In 1978 a combination lock which could be set by the user to a sequence of his own choosing was invented by Andrew Elliot Rae.<ref>{{cite web |last1=Rae |first1=Andrew E. |title=Combination lock |url=https://patents.google.com/patent/US4290286A |website=Google Patents}}</ref> At this time the electronic keypad was invented and he was unable to get any manufacturers to back his mechanical lock for lockers, luggage, or brief-cases. The silicon chip locks never became popular due to the need for battery power to maintain their integrity. The patent expired and the original mechanical invention was instantly manufactured and sold worldwide mainly for luggage, lockers, and hotel safes. It is now a standard part of the luggage used by travellers.