See also: Precision balance (homonymy)

The precision balance belongs to the parts of Artillerie medieval known as with Contrepoids. Introduced in France with the current of the 12th century, its use perduré until the 16th century.

Its name comes from the Occitan (Roman language of Europe) trebucca which means: “which brings troubles”. It is made of an assembly binding a Verge to an articulated counterweight also called Huche. At the other end a pocket was attached in which the projectile was placed, generally a ball of cut stone.

History of the precision balance

The precision balance was introduced in France at the 12th century. The Croisade S were probably the engine which pushed to develop this type of weapons of seat. The precision balance is an alternative of the Mangonneau in the sense that its counterweight, also called Huche, is articulated. This confers many advantages to him, in particular with regard to the balancing of the weapon. The precision balance requires also less people to take again her initial position.

The golden age of the precision balance is at the 13th century. It was in particular used during the Albigensian Crusade, as attest it the Fouille S made with Carcassonne and the Château of Montségur for example. It was called the “wolf of war” under the reign of the king d' Angleterre Edouard {{Ier}} which used many specimens of them to conquer the Wales then the Scotland.

It is thought commonly that the precision balance could draw from the ball S heavy until approximately 120  Kilogram S on a distance from a little more 200  Mètre S. It was necessary that there is a minimal range of 150-200 meters not to be with range of the besieged archers. Such a weapon was especially used as a weapon of seat. It was thus pointed on a precise point of the enemy Fortification S which were then bombarded. The precision balance also constituted an effective weapon of Dissuasion. Indeed, certain fortified towns capitulated since besieged saw the erection of the machine.

An alternative of the more mobile and light precision balance was also developed later which comprised two counterweights located on both sides rod and which, so bore the name of couillard or also of crossed out.

The precision balance was gradually replaced by artillery with powder until the suspension of its employment during the 16th century. The two systems of armament cohabit indeed during approximately three centuries since the artillery with powder was introduced towards the beginning of the Guerre One hundred Year old opposing the French to the English, and at the time of the seat of Orleans. It should be said that at the time, the handling of the precision balance was of a simpler employment and especially less dangerous than artillery with powder.

One of last the use of the precision balance as a weapon of seat which was consigned in writing date of 1521. Being with powder court with gun, Hernán the Cortes made assemble a precision balance at the time of the seat of the capital Aztèque Tenochtitlán. One reports that it was useful only once, because of a failure of design which caused its own destruction during the first shooting. The sources do not make it possible to check if it is really about a precision balance or of a catapults.

These counterweight weapons fell into the lapse of memory until Napoleon {{Romain|III}} carries a new interest to the medieval time and these weapons in particular.

The description of this precision balance made by Purple-the-Duke in his medieval encyclopedia as reproduced low date also of the 19th century.

Features

If dimensions and the mass of the machine can largely vary from a model with another, it does not remain about it less than one precision balance of intermediate size was to have the following features:

• Length of the Rod: 8 to 12 meters;
• Mass of the counterweight: between 10 and 18 tons;
• Mass of the ball S: from 80 to 100 kilograms;
• Carried maximum: a little more than 200 meters;
• Number of being useful: approximately 60 people (carpenters, masons stone, operations, etc);
• Rate of shooting: 1 to 2 per hour.

Detailed description

Note: This description reproduces that of the medieval Encyclopédie of Purple-the-Duke which recapitulates theoretical knowledge on the precision balance at the end of the 19th century.

Villard de Honnecourt   we gives to the Plan of one of these large precision balances to Contrepoids, so strong employees during the Guerre S of 12th and 13th century. Though the rise in this machine misses in the Manuscrit of our Picardy Architecte of the 13th century, however the figure which it presents and the explanation help to include/understand these kinds of machines. Villard writes with the bottom of its plan the following legend (translated Former French):

“If you want to work the strong machine that precision balance is called, made here attention. Here are the sand pits as they rest with ground. Here in front of ·· Winch S and the double cord with which one plasters the Verge. See can it on this other page. There is large burden to plaster, because the counterweight is very pesant  ; because there is a Huche full of ground, which has ·· large Measuring apparatus S length and ·· foot S broad, and ·· basic feet. And with stripping flèche  (*), think! And give you guard of it, because it must be maintained with this cross-piece of the front. ”
(*) the arrow indicates a ankle.

The plan given by Villard watch two Sand pit S parallel S spaced one of the other of eight feet, and being each one thirty-four feet length. With fourteen feet of the former end of the sand pits is a cross-piece which, with the scale, appears to have twenty-five feet of long  ; then four large Bracket S, a horizontal Cross of Saint-Andrew enters the two sand pits longitudinales  ; close to the posterior end, both Winch S accompanied by two large Spring S horizontal in Wood. It is there an enormous machine, and Villard at a rate of recommending to take guard with oneself at the time when the rod is stripped.

The precision balance of Villard

Villard gives only the plan of the sand pits on the ground, but number of Vignette S of manuscripts make it possible to supplement the figure. One of the important points of the description of Villard, it is the cube of the Contrepoids.

These bins are not Parallélépipède S, but of the portions of Cylindre S in the majority of old the représentations : however, by giving to this bin the form indicated in figure 1, and the dimensions expressed in the text of Villard, we find a cube of approximately 20 meters; by putting the meter of ground at 1  200  kg, we obtain 26  000  kg.

“There is large burden to plaster. ”

To make change place a similar mass, one needed a Levier of large a Length: the Verge was this lever; it had of four Toise S with six measuring apparatuses length (from eight to twelve meters), was composed of two parts of Bois strongly joined together by Frette S of Fer and cords, and receiving between them two a axis out of worked iron as the detail indicates it has .

The Tourillon S of this axis entered the two vertical B , reinforced parts, shoed at their end, and maintained in their plan by braces. In the event of rupture of the pivot, a rest C received the reinforcement It , in order to avoid the fall of the rod and all the damage that this fall could cause.

To operate the precision balance

Let us see how one operated this machine, whose profile géométral is given by figure 2. When the rod was left free, solicited by the counterweight C , it took the driving position AB . It was to make him give up this driving position which was needed a main effort of pulling because of the sharpness of the Angle formed by the cord of pulling and the verge  ; then, one had recourse to both large Ressort S of wood traced within Villard, and reproduced on our sight Perspective (figure 1).

The cords attached at the ends of these two springs came, while passing in the throat of two Poulie S of reference, to stick to ankle S planted in the second Treuil D (figure 2)   ; by operating this winch with wrong way, one bandaged the two cords as much as could allow it the two springs. Beforehand, the loop E , with its twin pulleys F , in which the cord of pulling passed, had been fixed at the ring G by means of ankle H (cf detail X ).

The pulley I rolled on a rope little tightened KL , in order to make the pulling of the two winches as direct as possible. At the time thus where it was a question of lowering the rod, while being thus prepared, one being useful being assembled to attach the double cord to the ring of the pulley of pulling, one released the turned winch with wrong way, the springs tended to take again their position, they made do one or two turns with the winch D in the direction wanted for demolition and thus helped with the men who started to operate the two winches, which required of as much less force that the rod moved away from the vertical.

Then one detached the loops of the cords of the springs and one continued demolition on the two winches in ab and has' B' . Eight men (two per lever for a machine of the dimension of that represented figure 1), as of the moment that the rod had left the vertical line, could bring this one according to the position has' B' . The charger took the pocket out of leather and cords M , arranged it in the horizontal Rigole in Me , placed a projectile inside, then, of a blow of mallet, the decliquor made jump ankle H .

The rod, not being retained, took again the driving position by a fast movement, and sent the projectile to far. It is here where one does not go, fault of the experience gained by the practice, an exact account of the force S combined, Révolution followed by the projectile, and from the moment when it must leave his pocket.

Some commentators appear to have regarded the pocket of the projectile as a true sling being composed of two fasteners, including one fixed and the other mobile, so that, by the movement of Rotation printed to the projectile, one of the two fasteners of the sling left its point of provisional fastener, and the projectile thus given up with itself described in space a Parabole more or less lengthened.

Supports of sling

Initially, many causes could modify the setback of the one of the cords of the sling  : the Mass of the projectile, its pulling more or less pronounced on one of the two cords, a light obstacle, a Friction. It could be done or that the setback took place too early, then the projectile was launched vertically and fell down on the head of the tensioners; or that it décrochat, and that then, folded back at all with violence on the Rod, it did not break it.

By consulting the Low-relief S and the Label S of the Handwritten S, we do not see appearing these two Bride S of sling and the provisional fastener of the one of elles  ; on the contrary, the supports of the sling appear to make one Faisceau of cords or Lanière S, with a pocket at the end, as our figures indicate it. Moreover, we often see, in the labels of the manuscripts, one second fastener placed below the fastener of the sling, and which appears to have to attach this one, as well as the fact even label 3 reproduced in the editions Frenchwoman and English of Villard de Honnecourt.

Here, the tensioner holds with the hand this secondary support and appears to attach it to the tail of the sling. It is this support, this under-tensioner, which in our two figures 1 and 2 we traced in P , supposing it double and being able to be attached to various points of the tail of the fronde  ; one will see why.

Movement of the rod

That is to say of figure 4 the movement of the Rod, when after being lowered, it takes again abruptly the position Verticale by the effect of the Contrepoids; the Projectile will have to follow the curve ABC . However it arrives one moment when the sling will be Normale with the arc of Cercle describes by the rod, i.e. where this sling will be exactly in the prolongation of the rod which is the radius of this arc of circle. Then, the Projectile, driven by a Centrifugal force considerable, will tend to escape from its pocket.

It is clear that the sling will more quickly be brought in the line of prolongation of the rod according to whether this sling is shorter and that the mass of the projectile will not be launched as regards enemies, but on the contrary on those which are placed behind the machine.

There was thus the first calculation to make to give to the sling a desired Length so that having to launch a mass, it arrived in the prolongation of the line of the rod when this one was close reaching its Apogée. But it was then necessary to determine by an abrupt jolt the departure of the projectile, which differently would have left the ray while moving away from the machine almost vertically.

It was to determine this jolt that the under-tensioner P was made. If this under-tensioner P were attached in P' , for example, so as to form with the rod and the tail of the sling the Triangle P' GOLD , the tail COp' could not leave any more the Angle P' GOLD , nor to be driven on the point of Rotation O .

But the projectile C continuing its race forced the pocket of the sling to obey this movement of Impulsion until the moment when this pocket, being reversed completely, the projectile given up with itself was called by the Centrifugal force and it impetus given by the abrupt stopping of the under-tensioner to describe a Parabole It E .

If, as indicates it the layout S , the under-tensioner P were fixed in P'' , i.e. more close to the fastener of the tail to the sling, and formed a triangle P'' O' R' “  whose angle O' was less Obtus that of the preceding example, the jolt was felt earlier, the portion of the free left sling described an arc of circle It' It'   ”, in consequence of the principal movement of the verge  ; the projectile It''' , abandoned to itself under the double movement of the Centrifugal force principal and the secondary centrifugal force caused by the stop P'' , was launched according to a parabolic line It''' E'' , approaching more line Horizontal E that in the preceding example.

In a word, plus the under-tensioner P was roidi and fixed close to the fastener of the sling, plus the projectile was launched horizontalement  ; more on the contrary this under-tensioner was releases and attached close to the pocket of the sling, more the projectile was launched vertically. These under-tensioners were thus a means necessary to regulate the shooting and to ensure the departure of the projectile.

If the shooting had to be regulated, it was necessary to avoid the destroying effects of the counterweight which, arrived at its extreme point of fall, was to cause a terrible jolt with the rod, or to break all the assemblies of the braces. For this purpose, not only the movement of the counterweight was double, i.e. this counterweight was attached to two Bielle S, with two pivots, but still often at the same rods were fixed Masse S in rocker, as show it our preceding figures.

Here which was the effect of these masses T . When the rod was concerned abruptly under the influence the Huche charged with stones or ground, the masses T while going down quickly exerted an influence on the rods at the time when the bin arrived at the extreme point of its fall, and where it was retained by the opposite resistance of the rod. The masses not having to undergo this resistance directly, continuing their movement of fall, made incline the rods according to a line gh and thus partly destroyed the movement of jolt printed by the abrupt tension of these rods. The masses T broke up, up to a certain point, the vertical pulling produced by the bin, and neutralized the jolt which had made break all the pivots without deteriorating of anything the fast movement rod, in substituent a Frottement on the pivots with a shock produced by an abrupt tension.

These counterweight machines were of use until the moment when the Artillerie with fire replaced all the machines of jet of the Moyen-âge.

The precision balance of the head office of Cherbourg

The scientist bibliophile Mr. Pichon has an account (attachment) of what was paid for the transport of one of these machines in 1378, which had been used with the seat as Cherbourg.

Here this curious document, that its owner agreed to communicate to us:

“The Thomin monster the middle-class man of Pontorson gouvernour of the machine of the aforesaid the city, of the maistre Carpenter, other carpenters, of Mason S and Cancour S, tensioners and charrets to count the cariot which carries the rod of iceluy engin  ; for three charreltiers who are ordennés to be used that machine with the seat as Cherbourt, come to Carentan, and us Endouin Channeron, dottor in the seigniory, Bailly of Costentin and Jehan of the Islands, bailly illec for the roy our lord be grounds which were with the roy of Navarre, made and appoint in ceste part, from our lords the made généraulx roy our lord for the fact of the known as seat; the {{Romain|XV}} day of November the year {{Romain|MCCCLXXVIII}} .
And firstly:
Known as Thomin, the maistre gonduom of the known as machine, jours.

vault for days. ........

Sum Ci-dessus.

Michel Rouffe, maistre carpenter of the known as machine, jours.

vault for days. ........

Etc”

Follows the account of the carpenter, masons, tensioners, carts and horses. This attachment makes known the importance of these machines which required a personnel so many to assemble them and to make them act.

The figure of forty tensioners indicates enough the power of these engins : because to suppose that they were divided into two brigades (their service being very tiring, since they were in charge of the operation of the winches), one thus needed twenty tensioners to lower the rod of the precision balance. The masons were probably employed to level the grounds of level on which one sat the engin .

The precision balance of the Albigensians

Pierre of Be worth-Cernay, in its Histoire of the Albigensians , speaks about many Mangonneau X drawn up by the army about crossed in front of the castle of the Terms, and which threw against this place of the enormous stones, so that these projectiles made several breaches.

With the seat of the castle of Minerve (in Minervois), known as this same author, one raised with dimensions Gascon S a machine of those which one names Mangonneau X, in which they worked night and day with much heat. Pareillement, at midday and north, one drew up two machines, knowledge one of each with dimensions. Lastly, of with dimensions of the Count, i.e. with the the East, was excellent and immense a Pierrière, which each day cost twenty-and-a books for the Salaire of the workmen who were employed there.

With the seat of Castelnaudary, undertaken against Simon de Montfort, the count of Toulouse made “prepare a machine of monstrous size to ruin the Muraille S of the Château, which launched enormous stones, and reversed all that it reached… One day, the count (Simon de Monfort) advanced to destroy the aforesaid machine; and like the enemies had surrounded it by ditches and of barriers so much that our people could not arrive there…” Indeed, there was always the care to surround these machines of barriers, of trays, to as well prevent the enemies from destroying them as to preserve the men who served them.

With the seat of Toulouse, Pierre of Be worth-Cernay tells that, in the combat where Simon de Monfort was killed, “the count and the little of world which was with him withdrawing itself because of a hail of stones and unbearable cloud of flêches which overpowered them, stopped in front of the machines, behind trays, to take cover from ones and autres  ; because the enemies launched on ours an enormous quantity of stones by means of two precision balances, a Mangonneau and several machines…”

At this point in time Simon de Monfort was reached of a stone launched by a Pierrière which served of the women, on the place of Saint-Sernin, i.e. with hundred measuring apparatuses at least of the place where the combat was delivered. Sometimes the former authors seem to distinguish, as in this passage, the precision balances of the mangonneaux one. The mangonneaux ones are certainly machines with counterweight, like the precision balances, but the mangonneaux ones had a fixed mass placed at the tail of the rod instead of a mobile mass, which gave them a particular quality.

Villard de Honnecourt calls the counterweight machine suspended by rods, with counterweight in form of bin, trébuchet  ; from where one must conclude that if the mangonneau is also a machine with counterweight, it can be only the machine with beam, such as that illustrated in the Bas-relief of Saint-Nazaire de Carcassonne  and in much of labels of manuscripts.