Editing Crossbow (section)

==Construction==
[[File:Han crossbow trigger mechanism.jpg|thumb|[[Qin dynasty|Qin]] and [[Western Han dynasty]] crossbow trigger pieces.]]
[[File:Noix corde carreau arbalette.svg|thumb|[[Medieval Europe]]an crossbow nut mechanism: {{ordered list|item_style=margin-bottom: 0| Nut| String| Quarrel| Trigger}}]]
[[File:Nuss Armbrust.jpg|thumb|16th century crossbow nut excavated at [[Harburger Schloßstraße]], [[Hamburg-Harburg]], Germany]]

A crossbow is essentially a [[bow (weapon)|bow]] mounted on an elongated frame (called a tiller or stock) with a built-in mechanism that holds the drawn [[bow string]], as well as a [[trigger (firearms)|trigger]] mechanism, which is used to release the string.

=== Chinese vertical trigger lock ===

The Chinese trigger was a mechanism typically composed of three [[Casting (metalworking)|cast]] [[bronze]] pieces housed inside a hollow bronze [[Housing (engineering)|enclosure]]. The entire mechanism is then dropped into a carved slot within the tiller and secured together by two bronze [[Dowel|rods]].{{sfn|Loades|2018}} 

The string catch (nut) is shaped like a "J" because it usually has a tall erect rear spine that protrudes above the housing, which serves the function of both a cocking lever (by pushing the drawn string onto it) and a primitive rear sight. 

It is held stationary against tension by the second piece, which is shaped like a flattened "C" and acts as the [[Sear (firearm)|sear]]. The sear cannot move as it is trapped by the third piece, i.e. the actual trigger blade, which hangs vertically below the enclosure and catches the sear via a notch. 

The two [[bearing surface]]s between the three trigger pieces each offers a [[mechanical advantage]], which allow for handling significant draw weights with a much smaller pull weight. 

During shooting, the user will hold the crossbow at eye level by a [[Pistol grip|vertical handle]] and aim along the arrow using the sighting spine for [[Elevation (ballistics)|elevation]], similar to how a modern [[rifleman]] shoots with [[iron sights]]. 

When the trigger blade is pulled, its notch disengages from the sear and allows the latter to drop downwards, which in turn frees up the nuts to pivot forward and release the bowstring.

{{blockquote|The {{lang|zh-Latn|nu}} ({{lang|zh|弩}}) [crossbow] is so called because it spreads abroad an aura of rage [{{tlit|zh|nù}}] ({{lang|zh|怒}}). Its stock is like the arm of a man, therefore it is called {{lang|zh-Latn|bi}} ({{lang|zh|臂}}). That which hooks the bowstring is called {{lang|zh-Latn|ya}} ({{lang|zh|牙}}), for indeed it is like teeth. The part round about the teeth [i.e. the housing box] is called the {{lang|zh-Latn|guo}} ({{lang|zh|郭}}) ["city wall"], since it surrounds the {{lang|zh-Latn|gui}} ({{lang|zh|規}}) [lug] of the teeth [i.e. the locking nut]. Within [and below] there is the {{lang|zh-Latn|xuan dao}} ({{lang|zh|懸刀}}) ["hanging knife", i.e. the trigger blade] so called because it looks like one. The whole assembly is called {{lang|zh-Latn|ji}} ({{lang|zh|機}})["machine" or "mechanism"], for it is just as ingenious as the [[loom]].{{sfn|Needham|1994|p=133}}|{{lang|zh-Latn|[[Shiming]]}}}}

=== European rolling nut lock ===

The earliest European designs featured a transverse slot in the top surface of the frame, down into which the string was placed. To shoot this design, a vertical rod is thrust up through a hole in the bottom of the notch, forcing the string out. 

This rod is usually attached perpendicular to a rear-facing lever called a ''tickler''. A later design implemented a rolling cylindrical pawl called a ''nut'' to retain the string. This nut has a perpendicular centre slot for the bolt, and an intersecting axial slot for the string, along with a lower face or slot against which the internal trigger sits. 

They often also have some form of strengthening internal ''sear'' or trigger face, usually of metal. These ''roller nuts'' were either free-floating in their close-fitting hole across the stock, tied in with a binding of sinew or other strong cording; or mounted on a metal axle or pins. 

Removable or integral plates of wood, ivory, or metal on the sides of the stock kept the nut in place laterally. Nuts were made of antler, bone, or metal. Bows could be kept taut and ready to shoot for some time with little physical straining, allowing crossbowmen to aim better without fatiguing.

=== Bow ===

Chinese crossbow bows were made of composite material from the start.{{sfn|Loades|2018}}

European crossbows from the 10th to 12th centuries used wood for the bow, also called the ''prod'' or ''lath'', which tended to be [[ash tree|ash]] or [[taxus|yew]].{{sfn|Loades|2018}}

Composite bows started appearing in Europe during the 13th century and could be made from layers of different material, often wood, horn, and sinew glued together and bound with animal tendon. These composite bows made of several layers are much stronger and more efficient in releasing energy than simple wooden bows.{{sfn|Loades|2018}}

As steel became more widely available in Europe around the 14th century, steel prods came into use.{{sfn|Loades|2018}}

Traditionally, the prod was often lashed to the stock with rope, [[whipcord]], or other strong cording. This is called the ''[[bridle]]''.{{sfn|Loades|2018}}

=== Spanning mechanism ===

The Chinese used [[winch]]es for large crossbows mounted on [[fortification]]s or [[wagon]]s, known as "bedded crossbows" (床弩). Winches may have been used for handheld crossbows during the [[Han dynasty]] (202&nbsp;BC – 9&nbsp;AD, 25–220 AD), but there is only one known depiction of it. 

The 11th century Chinese military text ''[[Wujing Zongyao]]'' mentions types of crossbows using winch mechanisms, but it is not known if these were actually handheld crossbows or mounted crossbows.{{sfn|Needham|1994|p=150}} 

Another drawing method involved the shooters sitting on the ground, and using the combined strength of leg, waist, back and arm muscles to help span much heavier crossbows, which were aptly called "waist-spun crossbows" (腰張弩).

During the [[Post-classical history|medieval era]], both Chinese and European crossbows used [[stirrup]]s as well as [[belt hook]]s.{{sfn|Needham|1994|p=150}} 

In the 13th century, European crossbows started using winches, and from the 14th century an assortment of spanning mechanisms such as winch pulleys, cord pulleys, gaffles (such as gaffe levers, goat's foot levers, and rarer internal lever-action mechanisms), cranequins, and even screws.{{sfn|Loades|2018}}<ref>{{cite web|last1=Ixax|first1=belle|title=Crossbow Reviews 2017|url=http://thetagtech.com/best-crossbow-reviews|website=Archer's Café|access-date=9 March 2017}}</ref>

<gallery>
File:Eastern Han Battle Scene on Brick (9873154043).jpg|Battle scene depicting a man spanning a crossbow using a winch mechanism, possibly mounted on a frame, [[Han dynasty]]
File:Northern song Cavalry.jpg|[[Song dynasty]] cavalry wielding crossbows with stirrups
File:The Martyrdom of St Sebastian (detail).jpg|Fifteenth century crossbowman using a stirrup along with a belt hook and pulley
File:Dictionnaire raisonné du mobilier français de l’époque carlovingienne à la Renaissance, tome 5 - 043.png|Detailed illustration of a goat's foot lever mounted on a crossbow that is half-spanned
File:Armborst 2, Nordisk familjebok.png|Illustration of a gaffe lever mounted on a crossbow that is nearly at full-span.
File:CAH 0153r.png|Illustrations of Leonardo da Vinci's [[rapid fire crossbow]] in the 15th-century [[Codex Atlanticus]]. Note the internal lever mechanism is fully extended to catch the draw string.
File:Balester 2.jpg|Internal mechanical illustration of a German [[bullet-shooting crossbow]]'s self-spanning mechanism
File:Armborst 4, Nordisk familjebok.png|Twentieth century depiction of a [[windlass]] pulley
File:Altarpiece of St Sebastian (detail).jpg|Fifteenth century crossbowman using a cranequin (rack and pinion)
File:HJRK A 2269 - Crossbow windlass, late 15th century.jpg|Iron cranequin, South German, late 15th century
</gallery>

=== Variants ===
[[File:Recurve crossbow with bolts.jpg|right|thumb|Modern recurve crossbow]]
[[File:Horton Hunter Supreme by IvE.jpg|right|thumb|Modern compound crossbow]]
[[File:HJRK A 108 - Wallarmbrust c. 1460-70.jpg|thumb|15th-century {{lang|de|Wallarmbrust}}, a heavy crossbow used for siege defense]]

The smallest crossbows are pistol crossbows. Others are simple long stocks with the crossbow mounted on them. These could be shot from under the arm. 

The next step in development was stocks of the shape that would later be used [[Stock (firearms)|for firearms]], which allowed better aiming. The [[arbalest]] was a heavy crossbow that required special systems for pulling the sinew via windlasses. 

For [[siege warfare]], the size of crossbows was further increased to hurl large projectiles, such as rocks, at fortifications. The required crossbows needed a massive base frame and powerful windlass devices.<ref>{{cite book|last=O'Connell|first=Robert L.|date=1989|title=Of Arms and Men: A History of War, Weapons, and Aggression|url=https://archive.org/details/ofarmsmenhisto00ocon|url-access=registration|publisher=[[Oxford University Press]]|isbn=0195053591|page=[https://archive.org/details/ofarmsmenhisto00ocon/page/65 65]}}</ref>

<gallery class="center">
File:Zhugenu-springautumn.jpg|Double shot repeating crossbow, also known as the Chu state [[repeating crossbow]] ({{lang|zh-Latn|chuguo nu}})
File:Two-bow crossbow wjzy.jpg|Mounted double bow crossbow
File:Chuangzi Nu1.jpg|Mounted triple bow crossbow
File:Liannu.jpg|Multi-bolt crossbow without a visible nut or cocking aid
File:Gastraphetes - catapult ancestor - antica catapulta.jpg|Cocking of a Greek {{lang|grc-Latn|[[gastraphetes]]}}
File:Roman crossbow. Pic 02.jpg|Gallo-Roman crossbow
File:B Osma 85v.jpg|Earliest European depiction of cavalry using crossbows, from the [[Catalonia|Catalan]] manuscript ''Four Horsemen of the Apocalypse'', 1086
File:Martyrium of Saint Sebastian. Pic 03.jpg|[[Late Middle Ages|Late medieval]] crossbowman from c. 1480
File:FrenchCrossbowMan.JPG|15th-century French soldier carrying an [[arbalest]] and a [[pavise]]
File:Balestra Veloce.jpg|A reconstruction of Leonardo da Vinci's rapid fire crossbow as shown at the World of Leonardo Exhibition in Milan
File:Ballista-quadrirotis.jpeg|Early modern four-wheeled [[ballista]] drawn by armored horses (1552)
File:FrenchMountedCrossbowman.JPG|16th-century French mounted crossbowman ({{lang|fr|cranequinier}}). His crossbow is drawn with a rack-and-pinion ''cranequin'', so it can be used while riding.
File:Crossbow pistol IMG 3841.jpg|Pistol crossbow for home recreational shooting. Made by Frédéric Siber in [[Morges]], early 19th century, on display at Morges military museum.
File:French cross-bow grenade thrower Arbalète sauterelle type A d'Imphy circa 1915.jpg|French cross-bow grenade thrower {{lang|la|Arbalète sauterelle}} ({{literal translation|grasshopper crossbow}}) type A d'Imphy, circa 1915
</gallery>

=== Projectiles ===
[[File:Han Bronze Arrows & Lead Pellets (9884175776).jpg|thumb|Arrowheads and lead balls, [[Han dynasty]]]]

The arrow-like projectiles of a crossbow are called [[crossbow bolt|bolts or quarrels]]. These are usually much shorter than arrows but can be several times heavier. 

There is an optimum weight for bolts to achieve maximum kinetic energy, which varies depending on the strength and characteristics of the crossbow, but most could pass through common mail. 

Crossbow bolts can be fitted with a variety of heads, some with sickle-shaped heads to cut rope or rigging; but the most common today is a four-sided point called a [[Quarrel (projectile)|quarrel]]. A highly specialized type of bolt is employed to collect blubber biopsy samples used in biology research.

Even relatively small differences in arrow weight can have a considerable impact on its flight trajectory and drop.<ref name="CrossbowArrowDrop">{{cite web|url=http://www.bestcrossbowsource.com/crossbow-arrow-drop-charted-test-results/|title=Crossbow Arrow Drop – Charted Test Results|access-date=12 July 2019|website=BestCrossbowSource.com|archive-date=31 July 2019|archive-url=https://web.archive.org/web/20190731005020/http://www.bestcrossbowsource.com/crossbow-arrow-drop-charted-test-results/|url-status=dead}}</ref>

[[Bullet-shooting crossbow]]s are modified crossbows that use bullets or stones as projectiles.

=== Accessories ===
[[File:Crossbow telescopic sight reticle.JPG|thumb|right|The [[reticle]] of a modern crossbow [[telescopic sight]] allows the shooter to adjust for different ranges.]]

The [[Military history of China before 1912#Crossbow|ancient Chinese crossbow]] often included a metal (i.e. bronze or steel) grid serving as [[iron sights]]. Modern crossbow sights often use similar technology to modern firearm sights, such as [[red dot sight]]s and [[telescopic sight]]s. Many crossbow scopes feature multiple [[crosshairs]] to compensate for the significant effects of [[gravity]] over different ranges. In most cases, a newly bought crossbow will need to be sighted for accurate shooting.<ref>{{cite web|url=http://www.bestcrossbowsource.com/how-to-sight-a-crossbow|title=Sighting a Crossbow|work=Best Crossbow Source|access-date=28 October 2014|archive-date=28 October 2014|archive-url=https://web.archive.org/web/20141028114057/http://www.bestcrossbowsource.com/how-to-sight-a-crossbow/|url-status=dead}}</ref>

A major cause of the sound of shooting a crossbow is vibration of various components. Crossbow silencers are multiple components placed on high vibration parts, such as the string and limbs, to dampen vibration and suppress the sound of loosing the bolt.<ref>{{cite web|title=Crossbow|url=http://www.reference.com/browse/crossbow|website=[[reference.com]]|publisher=[[Columbia University Press]]|access-date=1 March 2015|archive-url=https://web.archive.org/web/20150402100105/http://www.reference.com/browse/crossbow|archive-date=2 April 2015}}</ref>