Wheelbarrow

Elements of history of the wheelbarrow

The question of the origins

In history of the techniques, it is often dangerous to suppose inevitably old what appears to go naturally from oneself: the history of the wheelbarrow seems to fall under this principle.

Étymologiquement, a wheelbarrow is a two-wheeled vehicle. The term, which appears at the 14th century, would be a diminutive of beroue , itself coming from bottom Latin birota , two-wheeled vehicle.

The machine would be a Chinese invention of the beginning of the Christian era, that is to say approximately ten centuries before it makes its appearance in Europe. However the sinologists remain often fuzzy, even contradictory in their assertions; the images are often late. The general Zhuge Liang (181 - 234), of the period of the Three kingdoms (IIIe century) would have supplied his armies and transported its casualties with wheelbarrows, tries which however appears badly to be appropriate for the rather powerful machine for the transport of loads on short distances. They would have also invented a wheelbarrow equipped with a small mast and comprising a sail, supposed to decrease the human effort when the wind is favorable.

According to Robert Temple, the wheelbarrow would have been invented in the South-east of China, one century before J. - C., by a legendary semi character named KB Yu . It is supposed to have manufactured a kind of sheep out of wooden and to have assembled it through the mountain. The wheelbarrows having been described a long time like “wood oxen” or “horses slipping,” it is probable that the invention of this legendary character is the wheelbarrow. According to this same author, the first representations of the machine would date from the 1st century after J. - C.

Until now, it was never question of wheelbarrow in the texts Latin S or Greek, that it is in the geometricians, the agronomists, the mechanics or the architects. However, study has recently highlighted the mention of what could be a wheelbarrow in two Greek inventories well gone back from -408/-407 and to -407/-406, with the result that the wheelbarrow would have been invented by the Greeks more than three centuries before its appearance in China, and would have been used in ancient Greece to transport loads on the building sites.

The first representation dates from the middle of the 13th century and we have neither illustrated representations nor of precise texts former to this date. The relative abundance of the representations in second half of the 13th century lets suppose an appearance in first half of this century.

In any agricultural scene, field where the Miniature S are numerous, one does not see wheelbarrows. The representations of mining work, where the wheelbarrow will hold an important place, are non-existent before the 16th century. There exist legends which allot the object to certain Dupin even with Pascal, both worms 1650. In fact one named “wheelbarrow” or “vinaigrette” a sedan-chair with two wheels appeared at that time and the invention was actually allotted of it to Pascal, even if no serious source confirms it.

A rather slow diffusion

In spite of the obvious advantage of the machine, always used in the campaigns and on the building sites, the diffusion of the wheelbarrow seems to have been rather slow and for limited uses, as suggest it later illustrations where still the stretcher and the wheelbarrow coexist. It could be that the wheelbarrow (vehicle with a wheel) was not very widespread before the 15th century, date from which one notes many mentions.

French They resorted to instruments easy to handle and saving the sorrow, which allowed a fast execution of work. Thus, instead of baskets or of containers, they used small carts which had two arms lengthened by behind; one filled them of ground, of clay or of stones then one took in hand the two arms, one pushed in front of oneself and the cart rolled on its wheel with the least sorrow to the building site; they finally were emptied, by leaning it with a hand, without no tiredness.

In 1821, French agronomists considered it regrettable that it is not known in several French areas.

Other indices as for the methods of this slow diffusion are accessible thanks to the building site from the Suez Canal (1859 - 1869) to the occasion of which the agents of the Compagnie discover that the wheelbarrow, of a use standardized in Europe for the agricultural work or of the Civil engineering, is unknown in Egypt. More surprising, various attempts carried out in order to make use the wheelbarrow by the Fellah S Egyptians show failures. Thus, the technical object does not carry in him the use which in is made nor the gestures which are associated for him. It does not predict either cultural obstacles against which can run up attempts at technical transfer nor choices of engagement in technological trajectories given.

Later the economists will seize the debate to underline this slowness in the diffusion of the machine which seems paradoxical taking into consideration its technical simplicity. Angus Maddison, wondering about the origins of disparities of development takes the example of the wheelbarrow to stress the importance of the process of imitation. According to him, the wheelbarrow would have passed from China towards Europe, but of the centuries after, in spite of the contacts privileged between India and the occident, the loads remained related to the head by the Indian workers, as they are it besides always in Africa.

The archeologists of the French Institut of oriental archeology of the Cairo run up today against the same type of difficulties as their predecessors when they prescribe the use of the wheelbarrow on their building site of Fouille.

Constitution of the solution “wheelbarrow”

The wheelbarrow is composed of five subsets:

the frame : constituted of two solidarized stretchers, function support of the unit;
the handles : function gripping, ordering and transmission of energy: it is the user interface;
the payload : container of transportable, it is the function tool (one calls function tool the function of the subset who in last analysis provides the function of the unit), fulfilled by a simple plate more or less equipped with walls, a bucket (named case, tank, trunk, etc) or specific equipment;
the travelling system : displacement by bearing (frictions minimum) allows by supporting part of the load;
the foot (even or bars): ensure with the wheel, a polygonal base of stable support, for the static periods of uses (loading, for example).

Alternatives - classification

The various alternatives of a technical object can be classified according to the solutions brought to fulfill the functions necessary. However, for very popular technical objects, the language running will give the same name to rather distant objects, or will give a name specific to others, which obviously are only of simple alternatives. Classification below thus will integrate objects like the devil and will leave of with dimensions “ wheelbarrows with snow ” or “ wheelbarrows with caterpillar . ”

; Alternatives according to the number of Wheel S :

If the wheelbarrow according to its etymology has two wheels, it is especially when it has of them only one which it is characterized like “wheelbarrow. ” However, when it has two wheels, those Ci are coaxial.

Critical: The wheelbarrow with two wheels allows greater capacities, more stable it can act with only one hand but it is very difficult, even testing, to carry out on the rough grounds while the wheelbarrow with a wheel is played of the irregularities of the ground. In addition the place necessary to operate the wheelbarrow with two wheels depends on the width of the Essieu.

One encounters some anecdotic cases of wheelbarrow with three wheels (out of star, to descend the staircases) or with four wheels (the feet are equipped with casters)

; Alternatives according to the position of the wheel axle compared to the load :

with before (more running);
below (see illustration " wheelbarrow of Tonkin" above);
in the medium: overhanging outside for the two wheels - with a careenage in medium of case for the mono-wheels.

; Alternatives according to the position of the payload :

the payload is on the stretchers : it is the type of the standard contemporary wheelbarrow. This provision allows the carryforward of load towards the wheel axle, but the study of the oldest representations shows that this possibility remained a long time unexploited. These alternatives are rather characteristic of the extreme occident of Europe and the Mediterranean basin.
the payload is suspended under the stretchers (completely or partially) which does not allow an effective carryforward of load towards the wheel but offers a greater stability. These alternatives are representative of the center of Europe, and in particular of Germany. A representation is visible in Of Re Metallica of Georgius Agricola (Basle, 1556).

; Alternatives according to the shape of the payload :

simple plate, or cross-pieces joining together the stretchers on which one poses the objects to be transported: wheelbarrow with pig (see illustration above);
plate with file: old wheelbarrow of the Station S, devil;
plate with file and racks (removable or fixed), it is the traditional wheelbarrow out of wooden of the campaigns;
tank out of sheet allowing the transport of granulated and liquid;
payload specialized: cistern, barrel, concrete-mixer, etc They are generally machines with two wheels.

; Alternatives according to the position of the feet :

Between the handles and the wheel (ordinary position)
In front of the wheel (family of the “devils”: wheel bag, provision bag with casters, etc)

Analyzes mechanical

The wheel

The size of the Roue is of a great influence on the behavior of a vehicle. It must be of very large Diamètre in front of the asperities of the ground applied to the risk, in the contrary case, to be fixed. This configuration confers on the wheel better a output. If the overhanging position of the wheels of cart authorizes big sizes, the study below watch that in the case of the wheelbarrow there exists a limit not to be exceeded.

Influence longitudinal position of the case

The recourse to the wheel reduces resistance to advance, but the use of only one wheel (or only one axle) inevitably does not relieve the pusher which must also support part of the load. One of the main interests of the wheelbarrow in the transport of the goods can show by a static mechanical study.

The consideration of the balance of the Châssis of a wheelbarrow on a ground without declivity brings to consider three mechanical actions external modélisables by force S.

the Poids of the unit made up of the wheelbarrow and its loading, represented by a force ^{$\ vec {P} \,$} applied to the center of mass G ;
the action of the wheel on the frame, represented by a force ^{$\ vec {R} \,$} applied to the center of the connection C . A prior study of the wheel alone proves that this action is quite perpendicular on the ground if the Liaison pivot between the wheel and the wheelbarrow is perfect (without friction) ;
the action of the pusher on the handles, represented by a force ^{$\ vec {F} \,$} applied to the point M . This action is partly unknown, and will be determined by this study.

Within the framework of the Static of the solid, the laws of Newton give us two relations between these three forces so that balance is respecté :

the sum of the force S is null :
(1) : $\ vec {P} + \ vec {R} + \ vec {F} = 0$ ;
the sum of the moment S is null ; by expressing them for example in the center of the wheel C , one obtains the relation suivante :
(2) : M (P) _C + M (R) _C + M (F) _C = 0.

As the weight and the action of the ground are vertical, necessarily so that the vectorial equality (1) is possible, the action of the pusher is too. On the level of the position of the wheeler, balance is obtained when the articulations of the shoulders are in the same vertical plan as the wrists and the supports on the ground. Then the equation translates the fact that the wheel and the pusher share the load.

^{$\ vec {P} = (\ vec {R} + \ vec {F}) \,$}, is in intensité : P = R + F .

The writing of the moments at the point C selected leads to the cancellation of one of the terms and gives a direct relationship between the weight ^{$\ vec {P} \,$} and the action of the pusher ^{$\ vec {F} \,$} soit :

(2): M (P) _C + M (F) _C = 0.

By developing this equation, one obtains a relation binding the intensities of these efforts to dimensions of the wheelbarrow, that is to say a P – b F = 0 or F = P a/b. This relation describes what is called the action leverage in support here on the wheel. Therefore, to relieve the pusher, i.e. to reduce the intensity of the force necessary to raise the handles, there exist three steps:

to limit the load in the wheelbarrow to reduce P , which is contrary with the interest.
to decrease the report/ratio a/b is in:

increasing B i.e. by lengthening the stretchers, which can make the machine less handy beyond a certain length,
decreasing has , which wants to say that for the extreme it is necessary to place the wheel under the wheelbarrow. Thus if this value is null, the pusher does not have to force any more to support the load: it is exactly the geometry adopted on the barrows or the Pousse-pousse. This solution is also made profitable with the devil which is generally employed to move heavy and cumbersome loads. Solution imposes reduction of size of wheel so that the threshold of loading remains low, which would make the wheelbarrow more sensitive to the accidents of the ground because of a more precarious balance, from where the adoption of two wheels for the devil. In addition, the tilted shape of the wall before case contributes to the reduction in has by bringing the center of mass closer to before: it is a modification which was noted in the historical evolution of the machine.

Now if the wheelbarrow is put moving, it is necessary to add to the action of the pusher a component parallel on the ground, equal to the quantity of acceleration ( m G ) . The arm leans then in the imposed direction of walk. This push is independent of the geometry of the wheelbarrow. The problem is the same one (actuation) with a cart (2 wheels) or a “ chariot ” (which generally has 4 wheels). The maintenance of the movement however requires an effort which depends on rolling friction related to the nature of the ground. A hard ground returns well better than a fatty ground or too high grass.

; Balance on a slope : Finally when the wheelbarrow is on a slope, the action of the ground not being more parallel with the weight, necessarily the action of the pusher is affected.

In a rise (wheel of the wheelbarrow upstream), the three lines of mechanical action meet with the top of the ground. The pusher must lean ahead to maintain the machine. The case represented, unfavourable if one maintains the plate wheelbarrow, shows that the intensity of the action of the pusher remains however reasonable. Only its direction poses problem. It is materialized by a line uniting the wrists with the supports on the ground; it is also the direction of the arms then tended. The configuration is the same one for the descent or the rise, the effort of the pusher (tractor) being either driving (to advance) or resistant. However compared to a use on the dish, and in the case of the pusher, the effort of advance is well multiplied by ten.

In a descent (wheel downstream) all is reversed. The point of contest of the right-hand sides of forces is with the lower part of the ground. The study shows, there too that, the intensity of the action of the pusher is about the same one. To that the problem of the contents is added, especially if it is liquid. In a rise one can correct the plate by raising the wheelbarrow, in a descent that is not more possible as soon as the feet touch the ground.

Of Karl Marx with John Hicks, the debate a long time consisted in knowing if the systematic oblique in this change consisted of a saving in capital or a labor-saving . An argument in favor of the latter lies in the propensity of the man to develop average techniques to remove sorrow: this principle corresponds to the turning of production. ” The analyzes philological wheelbarrow proposed opposite remains purely speculative but illustrates this concept perfectly. However, it also highlights the relevance of progress of organization and economy of the capital…

The development of the Nanotechnologie S shows that the model continues to inspire the contemporary technicians with the nano wheelbarrow, the smallest mechanism of the world to date.

Around the wheelbarrow

The wheelbarrow in the literature and arts

“ the Wheelbarrow or the great inventions ” is a poem of Jacques Prévert, in Paroles :
: the peacock makes the wheel
: the chance makes the remainder
: God assoit inside
: and the man pushes it.
“ the Wheelbarrow ” is a poem of Edmond Rostand.
the Wheelbarrow of the vinegar manufacturer , a drama in three acts of Louis-Sebastien Draper.
the Wheelbarrow is a table of Salvador Dali (1951), which reveals the machine in some of her tables, as its “ raphaélesque Tête exploded view ” or “ the station of Perpignan ” where the wheelbarrow of station joined that of “ the Angelus ” of Millet, like that more ambiguous than form the couple of the bottom on the right (priors, after the Angelus?). In 1955, Dali had announced the turning of a film entitled “ the Wheelbarrow of flesh ,” in which heroin fell in love with a wheelbarrow…
“ Mrs Brouette ” is a film of Moussa Senna Absa.

Linguistic extensions

In connection with its form, the “wheelbarrow” is the name of a position in love between two partners.
Être “out of leather of wheelbarrow” means being hard, stiff, out of wood. Expression found at George Sand ( the Miller of Angibault ), Eugene Sweats ( Mysteries of Paris ), Henri Pourrat (Valiancies, jokes and adventures of Gaspard of the mountains)…

Sets of children (small or large…)

The play of the wheelbarrow consists in for two people simulating the push of a wheelbarrow, one playing the part of the tool, the other pushing it. Thus, one of the two partners goes the body about to horizontal, while advancing on the hands, the ankles maintained by the second. The teams of two make the race.

The races of wheelbarrows are also practiced, with true wheelbarrows, carrying a sometimes human loading, generally in the form of “acrobato-humorous” course more or less. Certain community local organize such races traditionally, following the example for example of Saligny (in the Vendée), which does not hesitate to be described as “Capital of the Wheelbarrow”.

The wheelbarrows are in addition built on a scale young people and constitute a Jouet appreciated.

Decoration

The wheelbarrow is often used like simple decoration in the gardens, generally out of flower-holder. They are at the beginning wheelbarrows traditional, more or less out of use and “recycled” with this use. But because of success, a specific production of decorative and whimsical wheelbarrows was born, of more or less wrought wood, in basket making, wrought iron, etc

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