Editing Crossbow (section)

=== 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]]}}}}