Wheellock - AbsoluteAstronomy.com

A wheellock, wheel-lock or wheel lock, is a friction-wheel mechanism to cause a spark for firing a firearm

Firearm

A firearm is a weapon that launches one, or many, projectile at high velocity through confined burning of a propellant. This subsonic burning process is technically known as deflagration, as opposed to supersonic combustion known as a detonation. In older firearms, the propellant was typically...

. It was the next major development in firearms technology after the matchlock

Matchlock

The matchlock was the first mechanism, or "lock" invented to facilitate the firing of a hand-held firearm. This design removed the need to lower by hand a lit match into the weapon's flash pan and made it possible to have both hands free to keep a firm grip on the weapon at the moment of firing,...

and the first self-igniting firearm. The mechanism is so-called because it uses a rotating steel wheel to provide ignition. Developed around AD 1500, it was used alongside the matchlock and was later superseded by the snaphance

Snaphance

A Snaphance or Snaphaunce is a particular type of mechanism for firing a gun . The name is Dutch in origin but the mechanism can not be attributed to the Netherlands with certainty. It is the mechanical progression of the wheel-lock firing mechanism and the predecessor of the flintlock firing...

(1560s) and the flintlock

Flintlock

Flintlock is the general term for any firearm based on the flintlock mechanism. The term may also apply to the mechanism itself. Introduced at the beginning of the 17th century, the flintlock rapidly replaced earlier firearm-ignition technologies, such as the doglock, matchlock and wheellock...

(c. 1600).

Design

The wheellock works by spinning a spring-loaded steel wheel against a piece of pyrite

Pyrite

The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...

to generate intense sparks which ignite gunpowder

Gunpowder

Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...

in a pan, which flashes through a small touchhole to ignite the main charge in the firearm's barrel. The pyrite is clamped in vise jaws on a spring-loaded arm (or 'dog') which rests on the pan cover. When the trigger is pulled, the pan cover automatically opens, and the wheel spins as the pyrite is pressed into contact.

A close modern analogy of the wheellock mechanism is the operation of a modern cigarette lighter

Cigarette lighter

Cigarette lighter:* Cigarette lighter receptacle, in-car electric socket.* Lighter, a portable device used to create a flame....

which spins a toothed steel wheel against a sparking material to ignite the fuel into a flame. However, the wheellock is used to send the flame to then ignite the charge in the barrel.

A wheellock firearm can be instantly readied and fired even one-handed, in contrast to the then-common matchlock firearms which must have a burning cord of slow-match ready if the gun might be needed, and which demand the operator's full attention and two hands to operate. The wheellock mechanism is complex to make, which made it relatively costly.

The "dog"

The dog is a spring-loaded arm pivoted on the outside of the lock plate. A sparking material, usually a small piece of iron pyrite

Pyrite

, is clamped and held by vice-like jaws at the swinging end of the arm. This dog has two possible positions to which it can be pivoted by hand: a "safe" position, in which the dog is pushed towards the muzzle

Muzzle (firearm)

The muzzle of a firearm is the end of the barrel from which the projectile will exit.Precise machining of the muzzle is crucial to accuracy, because it is the last point of contact between the barrel and the projectile...

of the firearm, and an "operating" position, where the dog is pulled towards the operator so that the pyrite in its jaws can engage either the top of the pan

Flash pan

The flash pan or priming pan is a small receptacle for priming powder, found next to the touch hole on muzzleloading guns. Flash pans are found on gonnes, matchlocks, wheellocks, snaplocks, snaphances, and flintlocks....

cover (see below), or (in the absence of the pan cover) the edge of a steel wheel bearing longitudinal grooves around its circumference. Flint

Flint

Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...

is not suitable as a sparking material in the wheellock because it is too hard and would quickly wear away the wheel grooves.

The wheel

The upper segment of this grooved wheel, made of hardened steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

, projects through a slot cut to its precise dimensions in the base of the priming pan

Flash pan

. This wheel is grooved on its outside circumference with three or more V-shaped grooves with transverse cuts at intervals to provide a friction surface for the iron pyrites. The wheel is fixed to a shaft, one end of which projects outside the lockplate. This outside projection is of square section to permit a spanner (wrench) to be engaged for subsequent tensioning of the lock. The other end of the shaft fits through a hole in the lockplate, and on this end is forged a cam

Cam

A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice-versa. It is often a part of a rotating wheel or shaft that strikes a lever at one or more points on its circular path...

, or eccentric

Eccentric (mechanism)

In mechanical engineering, an eccentric is a circular disk solidly fixed to a rotating axle with its centre offset from that of the axle ....

. One end of a short, robust chain (made of three or four flat, parallel links like a short piece of bicycle chain

Bicycle chain

A bicycle chain is a roller chain that transfers power from the pedals to the drive-wheel of a bicycle, thus propelling it. Most bicycle chains are made from plain carbon or alloy steel, but some are nickel-plated to prevent rust, or simply for aesthetics. Nickel also confers a measure of...

) is fixed to the cam, while the other end of the chain is held in a groove at the end of the longer branch of a large heavy V-spring which is generally retained by a screw and a headed bracket through upstands inside the lockplate.

The pan

As in all muzzle-loading firearms (prior to the introduction of the percussion cap

Percussion cap

The percussion cap, introduced around 1830, was the crucial invention that enabled muzzleloading firearms to fire reliably in any weather.Before this development, firearms used flintlock ignition systems which produced flint-on-steel sparks to ignite a pan of priming powder and thereby fire the...

), the pan

Flash pan

transmits the fire to the main charge of gunpowder inside the breech of the barrel, via a small hole (or "vent

Touch hole

A touch hole is a small hole, through which the propellant charge of a cannon or muzzleloading gun is ignited. In small arms, the flash from a charge of priming held in the flash pan is enough to ignite the charge within...

") in the side of the breech, that gives on to the pan. The priming pan of all wheellocks is provided with a sliding cover that has two purposes, the first of which is to contain the priming powder and afford it some protection from the elements (the second is examined below, under 'Operation'). The pan cover may be slid open and closed by hand, but it is also attached to an arm inside the lock plate, which is acted upon by the eccentric on the shaft of the wheel.

The sear or trigger mechanism

The trigger engages one arm of a "z"-shaped sear

Sear (firearm)

In a firearm, the sear is the part of the trigger mechanism which holds the hammer or striker back until the correct amount of pressure has been applied to the trigger; at which point the hammer or striker is released to discharge the weapon...

pivoting in its centre between two upstanding brackets riveted or brazed to the inside of the lockplate. The other arm of the sear passes through a hole in the lockplate, and engages in a blind hole on the inner side of the wheel, thus effectively locking it and preventing any rotation. When the trigger is pulled, the sear makes a slight anti-clockwise rotation (seen from above), so that the arm engaged in the wheel retracts, and the wheel is free to turn.

Preparing to fire

First, the dog is rotated forward to the "safe" position, and the priming pan pushed open (if it is not already so). After loading a powder charge and ball through the muzzle in the usual way, the operator takes his "spanner

Wrench

A wrench or spanner is a tool used to provide grip and mechanical advantage in applying torque to turn objects—usually rotary fasteners, such as nuts and bolts—or keep them from turning....

", slips it on to the square section of the wheel shaft, and turns it until a click is heard (about one half to three-quarters of a revolution), and the wheel is felt to lock in place, whereupon the spanner is withdrawn. What occurs is that when the wheel is turned, the mainspring is tensioned via the chain, which is wound partially around the shaft. The click is the sound of one end of the sear engaging in the blind hole on the inside of the wheel, as described above, thus immobilizing it.

The pan is then primed with powder, and the pan cover pulled shut. Finally the dog is pulled back so that the pyrite in its jaws is resting on the top of the pan cover, under some pressure from the spring at the toe of its arm.

Operation

On pulling the trigger of a wheellock firearm, the sear effects a slight rotation as described above. The end of the sear arm (that has hitherto locked the wheel and prevented it from turning) is disengaged, leaving the wheel free to turn under the tension of the mainspring. There is a subtlety here that is of vital importance: the "hole" in the side of the wheel, into which the sear engages, is not a parallel-sided shaft. If it were, then under the tremendous tension of the mainspring, it would require a huge force on the trigger to disengage the sear. Nor is the tip of the sear arm cylindrical, which would have a similar effect. Rather, the "hole" is a depression in the wheel (like a small crater), and the sear has a rounded end: the wheel is locked by reason of lateral force on the shaft of the wheel rather than vertical force on the sear.

As soon as the wheel is released by the sear, the longer arm of the mainspring pulls the chain engaged in it. The other end of the chain being fixed to the cam on the wheel shaft, the latter rotates at high speed, whilst the rotating cam pushes forward the arm to which the pan cover is attached, thus causing the pan cover to slide forward towards the muzzle of the piece, and the pyrites to fall (under tension of the dog spring) on to the now rotating wheel. This is the second purpose of a sliding pan cover: were the pyrites to engage a stationary wheel, it would almost certainly jam the mechanism: but the built-in delay allows the pyrites to slip off the sliding pan-cover on to an already rotating wheel.

The fast rotation of the wheel against the pyrites produces white-hot sparks that ignite the powder in the pan, which is transferred to the main charge in the breech of the barrel via the vent, and the gun discharges.

The wheellock took around a minute to load, prepare and fire. Many contemporary illustrations of a wheellock pistol in action show the gun held at a 90 degree angle rather than vertically: this was to ensure that the priming powder in the pan lay against the vent in the barrel, and avoided a 'flash in the pan' or misfire (this was not the case for the flintlock

Flintlock

, where the sparks had to fall vertically a certain distance on to the pan).

History

The invention of the wheel-lock in Europe can be placed at about 1500. There is a vocal group of scholars who believe Leonardo da Vinci

Leonardo da Vinci

Leonardo di ser Piero da Vinci was an Italian Renaissance polymath: painter, sculptor, architect, musician, scientist, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist and writer whose genius, perhaps more than that of any other figure, epitomized the Renaissance...

was the inventor. Drawings made by Leonardo of a wheellock mechanism date (depending on the authority) from either the mid-1490s or the first decade of the 16th century. However, a drawing from a book of German inventions (dated 1505) and a 1507 reference to the purchase of a wheellock in Austria may indicate the inventor was an unknown German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

mechanic instead.
In 1517 and 1518, the first gun control

Gun control

Gun control is any law, policy, practice, or proposal designed to restrict or limit the possession, production, importation, shipment, sale, and/or use of guns or other firearms by private citizens...

laws banning the wheellock were proclaimed by the Emperor Maximilian I

Maximilian I, Holy Roman Emperor

Maximilian I , the son of Frederick III, Holy Roman Emperor and Eleanor of Portugal, was King of the Romans from 1486 and Holy Roman Emperor from 1493 until his death, though he was never in fact crowned by the Pope, the journey to Rome always being too risky...

, initially in Austria and later throughout the Holy Roman Empire

Holy Roman Empire

The Holy Roman Empire was a realm that existed from 962 to 1806 in Central Europe.It was ruled by the Holy Roman Emperor. Its character changed during the Middle Ages and the Early Modern period, when the power of the emperor gradually weakened in favour of the princes...

. Several Italian states followed suit in the 1520s and 1530s — another argument used by the pro-German camp.

As Lisa Jardine relates in her account of the assassination

Assassination

To carry out an assassination is "to murder by a sudden and/or secret attack, often for political reasons." Alternatively, assassination may be defined as "the act of deliberately killing someone, especially a public figure, usually for hire or for political reasons."An assassination may be...

of William the Silent

William the Silent

William I, Prince of Orange , also widely known as William the Silent , or simply William of Orange , was the main leader of the Dutch revolt against the Spanish that set off the Eighty Years' War and resulted in the formal independence of the United Provinces in 1648. He was born in the House of...

of the Netherlands

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, in 1584, the small size, ease of concealment and user-friendly loading aspect of the wheellock, compared to more arduous handheld weapons, meant that it was used for curtailing the lives of public figures, such as Francis, Duke of Guise

Francis, Duke of Guise

Francis de Lorraine II, Prince of Joinville, Duke of Guise, Duke of Aumale , called Balafré , was a French soldier and politician.-Early life:...

and William himself. Jardine also argues that a stray wheellock pistol shot may have been responsible for the St. Bartholomew's Day massacre

St. Bartholomew's Day massacre

The St. Bartholomew's Day massacre in 1572 was a targeted group of assassinations, followed by a wave of Roman Catholic mob violence, both directed against the Huguenots , during the French Wars of Religion...

of French Huguenots in 1572.

Wheel-lock firearms were never mass-produced for military purposes, but the best preserved armoury collection at the Landeszeughaus

Landeszeughaus

The Landeszeughaus, in Graz, Austria, is the largest existing original armoury in the whole world and attracts visitors from all over the world. It holds approximately 32,000 pieces of weaponry, tools, suits of armour for battle and ones for parades....

Graz, Austria contains over 3,000 examples many of which were produced in small batches for military units.

Features

Among the advantages of the wheellock was a better resistance to rain or damp conditions than the matchlock, and the absence of a tell-tale glow, or smell from the burning slow match

Slow match

Slow match or match cord is the very slow burning cord or twine fuse used by early gunpowder musketeers, artillerymen, and soldiers to ignite matchlock muskets, cannons, and petards...

, itself a hazard in proximity to gunpowder

Gunpowder

. A slow match

Slow match

Slow match or match cord is the very slow burning cord or twine fuse used by early gunpowder musketeers, artillerymen, and soldiers to ignite matchlock muskets, cannons, and petards...

could be next to impossible to light in rain, whereas the wheellock allowed sparks to be generated in any weather, and the priming pan was fitted with a cover that was not opened until the instant the gun was fired. This made it feasible for the first time to conceal a firearm under clothing etc. The high production cost and complexity of the mechanism however hindered the wheellock's widespread adoption. A highly skilled gunsmith was required to build the mechanism, and the variety of parts and complex design made it liable to malfunction

Firearm malfunction

A firearm malfunction is the partial or complete failure of a firearm to operate as intended. Malfunctions range from temporary and relatively safe situations, such as a casing that didn't eject, to potentially dangerous occurrences that may permanently damage the gun and cause injury or death...

if not carefully maintained. Early models also had trouble with unreliable springs

Spring (device)

A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication...

, though this problem was quickly solved.

The wheellock was used along with the matchlock until both were replaced by the simpler and less-costly flintlock

Flintlock

, by the late 17th century. The wheellock mechanism however gave faster ignition than the flintlock, because the sparks were produced directly in the pan, rather than having to fall a certain distance from the frizzen

Frizzen

The frizzen, historically called the steel, is an "L" shaped piece of steel hinged at the rear used in flintlock firearms. It is positioned over the flash pan so as to enclose a small priming charge of black powder next to the flash hole that is drilled through the barrel into where the main...

External links

Wheel Lock from About.com, with an animated demonstration of the mechanism.

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Design

The "dog"

The wheel

The pan

The sear or trigger mechanism

Preparing to fire

Operation

History

Features

See also

External links