Padlock - Wikipedia, The Free Encyclopedia
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Padlock
An Interchangeable Core Padlock
with customized logo
PadlockFrom Wikipedia, the free encyclopedia
Padlocksare portable locks with
ashackle that may be passed
through an opening (such as a ring,
chainlink, or hasp staple) to
protect property from unauthorized
use, theft, vandalism, or even harm.
Contents
1 History
2 Rating
3 Components
4 Combination locks
5 Padlock icon symbolising
a secure web transaction
6 See also
7 External links
8 References
HistoryPadlocks have been used in China since the late Eastern Han Dynasty
(25220 CE). According to Hong-Sen Yan, director of the National
Science and Technology Museum, early Chinese padlocks were
mainly "key-operated locks with splitting springs, and partially keyless
letter combination locks".[1]Padlocks were made from bronze, brass,
silver, and other materials. The use of bronze was more prevalent for
the earlyChinese padlocks.[1]
There are padlocks dating to the Roman Era, 500 BC 300 AD.[2]They were known in early times by merchants traveling the ancient
trade routes to Asia and China.[3]
Padlocks with spring tine mechanisms have been found in York, England, at the Jorvik Viking settlement, dated
850 AD.[4]
Smokehouse locks, designed in England, were formed from wrought iron sheet and employed simple lever and
ward mechanisms. These locks afforded little protection against forced and surreptitious entry. Contemporary
with the smokehouse padlocks and originating in the Slavic areas of Europe, "screw key" padlocks opened with
a helical key that was threaded into the keyhole. The key pulled the locking bolt open against a strong spring.Padlocks that offered more key variance were the demise of the screw lock. Improved manufacturing methods
allowed the manufacture of better padlocks that put an end to the Smokehouse around 1910.
http://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/Helixhttp://en.wikipedia.org/wiki/Helixhttp://en.wikipedia.org/wiki/Smokehousehttp://en.wikipedia.org/wiki/Key_(lock)http://en.wikipedia.org/wiki/National_Science_and_Technology_Museumhttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/Thefthttp://en.wikipedia.org/wiki/Vandalismhttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/Shacklehttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpghttp://en.wikipedia.org/wiki/Lock_(device)http://en.wikipedia.org/wiki/Key_(lock)http://en.wikipedia.org/wiki/Keywayhttp://en.wikipedia.org/wiki/Helixhttp://en.wikipedia.org/wiki/Wrought_ironhttp://en.wikipedia.org/wiki/Englandhttp://en.wikipedia.org/wiki/Smokehousehttp://en.wikipedia.org/wiki/Key_(lock)http://en.wikipedia.org/wiki/National_Science_and_Technology_Museumhttp://en.wikipedia.org/wiki/Vandalismhttp://en.wikipedia.org/wiki/Thefthttp://en.wikipedia.org/wiki/Propertyhttp://en.wikipedia.org/wiki/Chainhttp://en.wikipedia.org/wiki/Shacklehttp://en.wikipedia.org/wiki/Lock_(device)http://en.wikipedia.org/wiki/File:Best_4B72_Roanoke_Logo_Padlock.jpghttp://en.wikipedia.org/wiki/File:Rusty_Padlock.jpg -
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1884 Central Pacific Railroad of Cal.
brass boxcar padlock
Medieval padlock in Kathmandu
Around the middle of the 19th century, "Scandinavian" style locks, or "Polhem locks", invented by the
eponymous Swedish inventor Christopher Polhem, became a more secure alternative to the prevailing
smokehouse and screw locks. These locks had a cast iron body that was loaded with a stack of rotating disks.
Each disk had a central cutout to allow the key to pass through them and two notches cut out on the edge of the
disc. When locked, the discs passed through cut-outs on the shackle. The key rotated each disk until the
notches, placed along the edge of each tumbler in different places, lined up with the shackle, allowing the
shackle to slide out of the body. The McWilliams company received a patent for these locks in 1871. The
"Scandinavian" design was so successful that JHW Climax & Co. of Newark, New Jersey continued to makethese padlocks until the 1950s. Today, other countries are still manufacturing this style of padlock.
Contemporary with the Scandinavian padlock, were the "cast heart" locks, so called because of their shape. A
significantly stronger lock than the smokehouse and much more
resistant to corrosion than the Scandinavian, the hearts had a lock
body sand cast from brass or bronze and a more secure lever
mechanism. Heart locks had two prominent characteristics: one was a
spring-loaded cover that pivoted over the keyhole to keep dirt and
insects out of the lock that was called a "drop". The other was a point
formed at the bottom of the lock so a chain could be attached to thelock body to prevent the lock from getting lost or stolen. Cast heart
locks were very popular with railroads for locking switches and cars
because of their economical cost and excellent ability to open reliably
in dirty, moist, and frozen environments.
Around the 1870s, lock makers realized they could successfully
package the same locking mechanism found in cast heart locks into a
more economical steel or brass shell instead of having to cast a thick
metal body. These lock shells were stamped out of flat metal stock,
filled with lever tumblers, and then riveted together. Although morefragile than the cast hearts, these locks were attractive because they
cost less. In 1908, Adams & Westlake patented a stamped & riveted
switch lock that was so economical that many railroads stopped using
the popular cast hearts and went with this new stamped shell lock
body design. Many lock manufacturers made this very popular style
of lock.
In 1877 Yale & Towne was granted a patent for a padlock that
housed a stack of levers and had a shackle that swung away when
unlocked. It was a notable design because the levers were sub-assembled into a "cartridge" that could be slid into a cast brass body
shell. The assembly would remain together by means of two taper
pins passed through the shell and cartridge. This design gave the
commercial padlock market a serviceable, rekeyable padlock. About twenty years later Yale made another
"cartridge" style padlock that employed their famous pin tumbler mechanism and a shackle that slid out of the
body instead of swinging away.
Although machining metal was a method that was available to lock makers since the early 19th century, it was
not economically feasible to do so until the very early 20th century when electrical generation and distribution
became widespread. Some of the earliest padlocks (c. 1905) that were made from a machined block of cast orextruded metal resemble today's modern padlock. Corbin and Eagle were one of the first lock makers to
machine a solid block of metal and insert a relatively new pin tumbler mechanism and a sliding shackle into the
holes machined into the body. This style of padlock was both strong and easy to manufacture. Many machined
body padlocks were designed to be disassembled so that locksmiths could easily fit the locks to a certain key.
http://en.wikipedia.org/wiki/Locksmithhttp://en.wikipedia.org/wiki/Machininghttp://en.wikipedia.org/wiki/Linus_Yale,_Jr.http://en.wikipedia.org/w/index.php?title=Yale_%26_Towne&action=edit&redlink=1http://en.wikipedia.org/wiki/Stamping_(metalworking)http://en.wikipedia.org/wiki/Patenthttp://en.wikipedia.org/w/index.php?title=Adams_%26_Westlake&action=edit&redlink=1http://en.wikipedia.org/wiki/Rail_transporthttp://en.wikipedia.org/wiki/Newark,_New_Jerseyhttp://en.wikipedia.org/w/index.php?title=JHW_Climax_%26_Co.&action=edit&redlink=1http://en.wikipedia.org/wiki/McWilliamshttp://en.wikipedia.org/wiki/Cast_ironhttp://en.wikipedia.org/wiki/Christopher_Polhemhttp://en.wikipedia.org/wiki/File:Kathmandu-05.JPGhttp://en.wikipedia.org/wiki/Central_Pacific_Railroadhttp://en.wikipedia.org/wiki/File:Central_Pacific_Railroad_of_Cal_brass_car_lock_1884.jpg -
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Viking Age padlock found at Birka.
Early padlock style, on the front gates
of St. Peter's Basilica
Ottoman style handmade padlocks in
Turkey
A high security padlock.
The machined body padlocks are still very popular today. The process of machining allows many modern
padlocks to have a "shroud" covering the shackle, which is an extension of the body around the shackle to
protect the shackle from getting sheared or cut.
In the early 1920s, Harry Soref started Master Lock off with the first laminated padlock. Plates that were
punched from sheet metal were stacked and assembled. Holes that were formed in the middle of the plates
made room to accommodate the locking mechanism. The entire stack of plates, loaded with the lock parts in it,
was riveted together. This padlock was popular for its low cost and an impact-resistant laminated plate design.
Today, many lock makers copy this very efficient and successful design.[5]
Die-casting became popular in the early 1930s among lock makers. Not only was it a very inexpensive way to
make padlocks, but it
allowed designers to design
padlocks with a broad
range of geometrical
features and ornate designs
that sand casting and
machining wouldn't allow.Some lock makers, like
Junkunc Brothers,
augmented their machined
solid body padlock
products with the less
expensive and more
attractive die-cast bodied
padlocks. The Wise Lock
Company embraced this
new medium in making anovel padlock that, with the key inserted, would split lengthwise along
the body in order to create an opening in the shackle. Chicago Lock
pioneered their new "double bitted wafer" and "ACE" products by
installing them into a die cast body. With the advent of inexpensive
machining done overseas and the overall poor perception of the
security of die cast locks, they no longer dominate today's padlock
market.
RatingForced entry involves the
use of tools such as
hammers, bolt cutters,
chisels, and drills;
consequently, forced entry
attacks exhibit obvious signs of entry. Surreptitious attacks involve
picks, bump keys, shims, unauthorized key duplication, and other
bypass techniques that, when employed, do not show obvious signs
of compromise.
A quantitative measure of a padlock's resistance to forced and
surreptitious entry can be determined with tests developed by organizations such as ASTM, Sold Secure
(United Kingdom), CEN (Europe), and TNO (The Netherlands).
http://en.wikipedia.org/wiki/Netherlands_Organisation_for_Applied_Scientific_Researchhttp://en.wikipedia.org/wiki/European_Committee_for_Standardizationhttp://en.wikipedia.org/wiki/Sold_Securehttp://en.wikipedia.org/wiki/ASTMhttp://en.wikipedia.org/wiki/Organizationhttp://en.wikipedia.org/wiki/Shim_(engineering)#Lock_pickinghttp://en.wikipedia.org/wiki/Bump_keyhttp://en.wikipedia.org/wiki/Slim_Jim_(lock_pick)http://en.wikipedia.org/wiki/Drillhttp://en.wikipedia.org/wiki/Chiselhttp://en.wikipedia.org/wiki/Bolt_cutterhttp://en.wikipedia.org/wiki/Hammerhttp://en.wikipedia.org/w/index.php?title=Die_cast_locks&action=edit&redlink=1http://en.wikipedia.org/wiki/Chicago_Lockhttp://en.wikipedia.org/w/index.php?title=Wise_Lock_Company&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Junkunc_Brothers&action=edit&redlink=1http://en.wikipedia.org/wiki/Die-castinghttp://en.wikipedia.org/wiki/Laminatehttp://en.wikipedia.org/wiki/Master_Lockhttp://en.wikipedia.org/w/index.php?title=Harry_Soref&action=edit&redlink=1http://en.wikipedia.org/wiki/File:Bilock.JPGhttp://en.wikipedia.org/wiki/Turkeyhttp://en.wikipedia.org/wiki/File:TurkishHandmadePadlocks.jpghttp://en.wikipedia.org/wiki/St._Peter%27s_Basilicahttp://en.wikipedia.org/wiki/File:Early_padlock.jpghttp://en.wikipedia.org/wiki/Birkahttp://en.wikipedia.org/wiki/Viking_Agehttp://en.wikipedia.org/wiki/File:Viking_Age_lock.png -
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Components
A padlock is composed of a body, shackle, and a locking mechanism. The typical shackle is a "U" shaped loop
of metal (round or square in cross-section) that encompasses what is being secured by the padlock (e.g., chain
link or hasp). Generally, most padlock shackles either swing away (typical of older padlocks) or slide out of the
padlock body when in the unlocked position. Unusually designed padlocks may include a straight, circular, or
flexible (cable) shackles. Some shackles split apart and come together to lock and unlock.
There are two basic types of padlock locking mechanisms: integrated & modular. Integrated locking
mechanisms directly engage the padlock's shackle with the tumblers. Examples of integrated locking mechanisms
are rotating disks (found in "Scandinavian" style padlocks where a disk rotated by the key enters a notch cut
into the shackle to block it from moving) or lever tumblers (where a portion of the bolt that secures the shackle
enters the tumblers when the correct key is turned in the lock). Padlocks with integrated locking mechanisms are
characterized by a design that does not allow disassembly of the padlock. They are usually older than padlocks
with modular mechanisms and often require the use of a key to lock.
The more modern modular locking mechanisms, however, do not directly employ the tumblers to lock the
shackle. Instead, they have a plug within the "cylinder" that, with the correct key, turns and allows a mechanism,referred to as a "locking dog" (such as the ball bearings found in American Lock Company padlocks) to retract
from notches cut into the shackle. Padlocks with modular locking mechanisms can often be taken apart to
change the tumblers or to service the lock. Modular locking mechanism cylinders frequently employ pin, wafer,
and disk tumblers. Padlocks with modular mechanisms are usually automatic, or self-locking (that is, the key is
not required to lock the padlock)
Combination locks
Main article: Combination lock
Combination padlocks do not use keys. Instead, the lock opens when its wheels are lined up correctly to
display the correct combination.
Padlock icon symbolising a secure web transaction
While executing secure transactions on the web, the submitted information is encrypted using a
Public-key cryptography. Some web browsers display a locked padlock icon while using such a
secure protocol.
See also
Pin tumbler lock
Kent Police Museum Home of the world's largest working padlock.
External links
inventors.about.com (http://inventors.about.com/library/inventors/bllock.htm) History of LocksLock Forums (http://lockforums.com) Discussion on Locks
References
http://en.wikipedia.org/wiki/File:Encrypted.pnghttp://lockforums.com/http://inventors.about.com/library/inventors/bllock.htmhttp://en.wikipedia.org/wiki/Kent_Police_Museumhttp://en.wikipedia.org/wiki/Pin_tumbler_lockhttp://en.wikipedia.org/wiki/Web_browserhttp://en.wikipedia.org/wiki/Public-key_cryptographyhttp://en.wikipedia.org/wiki/HTTP_Securehttp://en.wikipedia.org/wiki/Combinationhttp://en.wikipedia.org/wiki/Combination_lockhttp://en.wikipedia.org/wiki/Shackle -
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1. ^ abChi Sung Laih (22 January 2004).Advances in Cryptology: 9th International Conference on the Theory
andApplication of Cryptology and Information Security. Springer. pp. 326329. ISBN 978-3-540-20592-0.
2. ^"Roman padlocks" (http://www.historicallocks.com/en/site/hl/Articles/The-history-of-padlocks/Roman-Era-
500-BC300-AD/). Historicallocks.com. 2008-01-22. Retrieved 2011-11-03.
3. ^"AnIntroduction to the History of Locks" (http://www.locks.ru/germ/informat/schlagehistory.htm).
Locks.ru. Retrieved 2011-11-03.
4. ^"The Ancient Art of the Locksmith" (http://www.buildingconservation.com/articles/locks/locks.htm).
Buildingconservation.com. Retrieved 2011-11-03.
5. ^"Twenty-Two Plates Put In Laminated Lock" (http://books.google.com/books?id=4icDAAAAMBAJ&pg=PA49&dq=Popular+Science+1931+plane&hl=en&ei=GWolTZ3LHcqTnAeEkozrAQ&
sa=X&oi=book_result&ct=result&resnum=3&ved=0CCkQ6AEwAjgy#v=onepage&q&f=true) Popular Science,
March1932, p. 49
Retrieved from "http://en.wikipedia.org/w/index.php?title=Padlock&oldid=587096713"
Categories: Locks
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