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THE ROMANIAN PEASANT-CREATOR OF MECHANISMS

Iulian POPESCU

Abstract: The present contribution of Romanian peasants in the field of mechanisms: the takeover of solutions from others and their adaptation to local conditions, with additions and some solutions. They exemplify the mechanisms sawmills and other types of mechanisms at various installations.

1 Introduction

Here is an appreciation of a foreigner about Romanians’ technical talent: "As for the Romanian nation in general, it is enough to know them you see clearly that the Romanians are very skillful and are able to state in any profession, only to have learnt it."…" As for other crafts, they end up very well. Learn everything they see, and is not handiwork, after Turkish fashion, or after our habit, which may not be able to imitate very well." So it was written about Romanians in 1717 by Anton Maria del Chiaro of Florence, a teacher of the Cantacuzino family. With time, the Romanian peasant built all the tools and facilities that he needed. Each dwelling has almost all the tools and facilities for family life: loom, cart, plough, quern, saw, all the tools necessary for processing milk and grapes, the mechanism used to scare the birds in the vineyard - "sfarleaza la vie". In each village there were one or two more complex plants: mills operated by water, animals or the wind, sawmills, installations for pressing fruit, wool processing plants.

2 Creativity and Invention

Tools and facilities for life in the villages were created by many peasants - simple people without technical training. More complex installations have been made by some craftsmen, gifted with great technical creativity. Many of these plants contain mechanisms. These mechanisms are common to most similar facilities in different geographical areas. We usually meet connecting rod-crank and four-bar mechanisms, pin wheel gearings, screw

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presses, hammers type pendulum. These mechanisms were invented in remote times by different anonymous craftsmen. Some have been patented soon after the emergence of the steam machine. Generally, the Romanian peasant did not invent new mechanisms. They had already been invented by others long before. However, he saw mechanisms, understood their operation and then realised them for his household. But he did not have at his disposal: licenses, photos, projects! He used only what he had seen and understood, but he established the dimensions of the mechanisms by his skill, that is, made an empirical synthesis, which is evidence of creativity. Further, he disposed of other local conditions: other parameters of the water which turns the hydraulic wheel, other available space, another configuration of the land, etc., so he was obliged to make adjustments, changes, improvements. And these adaptations are included into the category of creativity. In this way, it is explained why in the popular technique there are not serial products. Each of them is unique, with sharp differences in comparison with other similar installations! Every plant has the producer’s contribution.

3 Examples of mechanisms for sawmills

In the Museum of Popular Technique from Dumbrava of Sibiu there are a lot of technical popular installations, including some sawmills. The sawmill brought from Polovragi – Gorj is built on two levels; the feeding carriage is shown in figure 1.

Fig. 1 Fig. 2 A main sketch of the sawmill is shown in figure 2. The hydraulic wheel spins the A tree, acting the connecting rod-crank mechanism ABCD, moving up the blanking tool used for boards. From the element CD the movement goes to the driving linkage CEFGHKLMN. The fork at M presses the

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wheel of friction N, ensuring the fore stroke and then withdraws. The kinematic scheme is shown in figure 3.

Fig. 3

The mechanism consists of an element manager, R, a dyad RRT and three dyads RRR. Here are some solutions chosen by the Romanian peasant: - Fig. 4: the metallic crank; - Fig. 5: the mobile sawmill and a part of the take-off chain;

Fig. 4 Fig. 5 - Fig. 6: the adjustable balance lever; - Fig. 7: the stacker – the wheel of friction.

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Fig. 6 Fig. 7 For this sawmill, the kinematics was studied using the method of the contours. What is of a great interest here is whether the craftsman has well chosen the correlation between rate of cutting (vas) and penetration speed (vav). If the ratio R = vas/vav is too high, productivity is low, the tear of the tool is low but the smoothness of the board is good. For low values of this ratio the productivity increases, as well as the roughness and the fraying of the tool. From table 1 we can notice that R is roughly constant, within the limits of the characteristics of industrial frame saws (R = 40…100), manufactured in the country and abroad by specialized factories (years 1960-1970).

Table 1

Fi YD3 vas vav Ratio 0 1.12783 1.193804 -1.437171E-02 83.06626 10 1.160998 1.188002 -1.444115E-02 82.26504 20 1.193466 1.142991 -1.400188E-02 81.63123 30 1.224122 1.057413 -1.302842E-02 81.16208 40 1.251841 .931861 -1.152726E-02 80.83975 50 1.275546 .7690861 -9.537555E-03 80.63766 60 1.294268 .5740234 -7.128561E-03 80.52445 70 1.307202 .3536227 -4.394524E-03 80.46895 80 1.313759 .1165092 -1.448248E-03 80.44836 90 1.31361 -.1274967 1.584822E-03 80.4486 100 1.306709 -.3679574 4.572558E-03 80.47081 110 1.293298 -.5944594 7.381907E-03 80.52925 120 1.273903 -.7972712 9.885602E-03 80.64975 130 1.249303 -.9679772 1.197025E-02 80.86523 140 1.220485 -1.100032 1.354531E-02 81.21129 150 1.188588 -1.189175 .0145523 81.71735 160 1.154834 -1.233656 1.497124E-02 82.40171 170 1.120459 -1.234212 1.482251E-02 83.26607 180 1.086646 -1.193804 1.416269E-02 84.29217

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In figure 8 the graphs of the tool’s stroke (the curve with greater magnitude) and of the inclination of the element MN presented in figure 3 (feed motion), are shown. It is noticed that the two movements are well correlated, which is proof of ingenuity.

Fig. 8

Another sawmill, from Tomeşti - Hunedoara (Fig. 9), has another driving linkage, based on a cylindrical gear with bolts (Fig. 10) and another gear cog wheel – cog rack (Fig. 11).

Fig. 9 Fig. 10

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Fig. 11 Fig. 12

This mechanism too can adjust its lead, according to the essence of wood, by changing the position of a nail to obtain the desired length of the rocker (Fig. 12). In figure 13 there are given the penetration speed curves (mm/s), on the y-coordinate, depending on the angle of the driving element (degrees), for various positions of the nail from figure 12 [5]. It is shown that by means of this very simple system, a craftsman succeeded in obtaining a large range of advances, according to the essence of the wood to be cut. To do this, he noted in pencil on the element EH (made of wood), near every hole, the essence of wood: oak, beech, fir.

250. 300. 350. 400. 450.-0.005

0.0

0.005

0.01

0.015

0.02

Fig. 13

The constructor peasant made the following contributions to the sawmill: - he set by himself the lengths of the elements of mechanism by which it assures the correct ratio between the two speeds (cutting and penetration); - he adapted the construction according to the parameters of the stream that he had at his disposal; - he correlated the cutting motion and the feed motion correctly.

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4 Other mechanisms built empirically by peasants

We will give examples of other original solutions of the Romanian peasants to some mechanisms: - Fig. 14: wheel with vertical shaft ("facaie") and the adjustable mechanism of the free distance between the millstones; - Fig. 15: plant of extracting water, gear pair with intersecting axes (Bosnia - Iasi);

Fig. 14 Fig. 15 - Fig. 16: mechanisms for producing ropes (Ţânţăreni, Gorj); two mechanisms called parallel-crank mechanism, where the connecting rods are leading elements; - Fig. 17: cog wheel and front toothed wheel;

Fig. 16 Fig. 17 - Fig. 18: windmill with gearing of a cone cog wheel with a front toothed wheel, and the shoe brake is observed; - Fig. 19: hammer press with double pendulums, guiding the desired trajectory.

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Fig. 18 Fig. 19 In figure 20 we present the diagram of the average force of collision, depending on time, obtained after dynamic study of the press from figure 19. We can see the effectiveness of the double pendulum-type mechanism, with two leading elements.

Fig. 20

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In figure 21 you can see a mechanism ("steamp") used for crushing ore or agricultural products, with a camshaft (Fig. 22) and cam followers with reciprocating motion. In figures 23 and 24 you can see a helical gear, with a small number of teeth, used in the processing of cotton (Cujmir area).

Fig. 21 Fig. 22

Fig. 23 Fig. 24

5 Conclusions

The Romanian peasant built the mechanisms which he needed empirically, without any calculations and without copying the dimensions from other craftsmen. He may have been influenced by other craftsmen's mechanisms but his mechanisms were different and adapted to the local conditions.

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References

1- Bucur C., Monumente de tehnica populara-categoria distinctă a patrimoniului cultural national, In: Cibinium, pp. 243-305, 1984.

2- Dogaru V., Aschierea lemnului si scule aschietoare, Ed. Did. Ped., Bucureşti, 1981.

3- Dudiţă Fl., Diaconescu D., Gogu Gr., Mecanisme articulate. Inventica, Cinematica, Editura Tehnică, Bucureşti, 1989.

4- Ghunaimat I., Cercetări privind istoria mecanismelor. Teza de doctorat, Univ. Craiova, 2006.

5- Popescu A., Contributii la evaluarea performantelor unor mecanisme create de-a lungul timpului. Teza de doctorat, Univ. ”Politehnica” Bucureşti, 2007.

6- Popescu I., Mecanisme ingenioase folosite de-a lungul timpului in tehnica populara romanească, Editura Tehnica, 1983.

7- Popescu I., Din istoria tehnicii, Vol. I – VI, Editura ”Sitech”, Craiova, 2002.