A combination lock (or permutation lock, word lock) is a keyless lock that uses a sequence of letters, numbers, or symbols to open the lock. Unlike keyed locks, combination locks require that a user know the proper sequence of characters to open the lock, much like knowing a password for a computer login. A combination lock works by correctly positioning internal components as the sequence is entered, usually through the use of one or more dials.
Combination locks are most commonly associated with safes, but are also popular in low security applications in the form of padlocks. Because they do not have keyholes through which to manipulate internal components, most combination locks are compromised through decoding or bypass rather than picking.
The earliest combination lock was excavated from a Roman tomb in Athens, Greece. Attached to a small box, it featured several dials instead of keyholes. In 1206, the Muslim engineer Al-Jazari documented a combination lock in his book al-Ilm Wal-Amal al-Nafi Fi Sina'at al-Hiyal (The Book of Knowledge of Ingenious Mechanical Devices). Muhammad al-Astrulabi (ca 1200) also made combination locks, two of which are kept in Copenhagen and Boston Museums. Gerolamo Cardano later described a combination lock in the 16th century.
Linus Yale, Jr. contributed the first modern style rotary combination locks in the early 1870s. In 1878, Joseph Loch (German) modified Yale's design for Tiffany's Jewelers in New York City.  For several decades Loch made many more improvements in the design and function of combination locks.
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Rotary Combination Locks
Add to me!
Pushbutton locks are a form of mechanical combination lock that uses numbered or lettered buttons to properly align internal components. Generally, pushing each button on the face of the lock rotates one or more wheels inside the lock. A user who knows the correct sequence of pushes can properly align all wheels and open the lock.
Pushbutton locks are popular as standard door locks and padlocks. Pushbutton padlocks are the most common type of lock boxes.
Electronic Combination Locks
- See Electronic Locks