Padlocks are external, portable locks that can be placed
in most locations, versus the traditional stationary lock, such as the type
that is built in to a door. Padlocks are also different in another regard: they
were designed specifically in order to protect against vandalism, defacement,
or any of type of forced entry. They are typically used to protect the contents
of storage units, such as sheds, but are very widely used for safety purposes
as well, such as for keeping employees out of potentially dangerous areas.
Padlocks are believed to have originated some time between the 5th and 3rd centuries BCE and the first empirical evidence suggesting their usage dates to the Roman Era, yet other forms of padlocks have been found in the Jorvik Viking settlement in York, England dating back to approximately 850 BCE.
The main components of a padlock are its body, which is the base of the lock, the locking mechanism, which is located inside the body, and the shackle, which is the usually curved metal rod that inserts into the body and clasps into the locking mechanism.
Brass is ideal for locks that come into prolonged or
constant contact with the elements and are therefore better for outdoor use,
such as sheds, gates and gardens or any scenario where the locks are bound to
get wet. Aluminum padlocks also provide protection against caustic or corrosive
environments but are lighter weight. They can also be color-coded.
Anodized aluminum is aluminum that has been put through an electrolytic passivation process. In this process an aluminum object, in this case the lock body, acts as a positive electrode (or anode) while a direct current is passed through an electrolytic solution. During the process, the current discharges oxygen on the surface of the aluminum, which coats the lock body in a layer of aluminum oxide. The layer of aluminum oxide is resistant against corrosion and as well is a better surface for paint primers, which is why color-coated padlocks are typically anodized.
Keyed Alike — Keyed alike refers to the creation of a source key, or one individual key that is used on all of locks. The same key cannot be used across manufacturer lines as different manufacturers do not use the same locks.
Keyed Differently — Keyed differently refers to a set of keys all of which are different and therefore each is used to operate a particular lock.Master Keyed — Master keyed can be seen as the crossing point between the keyed alike and keyed differently options. A master keyed lock is a lock for which a group of people each has their own key, but where one master key exists which can open every lock.