New Horse-drawn Side Delivery Rakes from Europe
by Paul Schmit of Luxembourg and Albano Moscardo of Italy
By a comparative test, the possible range of use of two side delivery rakes for hay making by horse traction was analyzed. The report in hand covers the rake REPOSSI 68/5 manufactured by the company REPOSSI Macchine Agricole s.r.l. from CASORATE PRIMO (PV – ITALY).
Tests and measurements during hay making in 2013 showed that this implement requires, in its different operating modes, relatively light draft power and is thus suited to a single horse hitch. By a good set-up of the gear ratio in the mechanical transmission and a precise setting of the working height of the raking teeth, this implement comes up with good operating results, even at the low working speed of a draft horse.
Adaptations on the hitch and traction devices as well as on the operating of the implement could raise the comfort and the safety at work, both for the horse and the driver.
In Northern Italy the two agricultural machinery manufacturers MAINARDI A. s.r.l. and REPOSSI Macchine Agricole s.r.l. produce a vast range of haying equipment with pto and hydraulic drive, also hay rakes with mechanical drive by the rear wheels. REPOSSI Macchine Agricole s.r.l. offers the pull type side delivery rakes in two working widths (2.60 and 2.90 m) as well as with two different rear wheel sizes (4.00-19 and 4.00-36) and two working directions (raking to the left and the right). The majority of the sold machines of this type (with annual production totals of 50 to 60 units) are currently used with small tractors and motor cultivators, often in the mountainous regions of the Mediterranean countries, South America, and Mexico. The technology of these rakes is based on implements which were developed in the 1940s, when animal traction still played an important role in Italy’s agriculture.
The REPOSSI company was founded in 1898 and is currently administered by Mr. Francesco and Gabriele REPOSSI in the fourth generation. The system for the inclination of the raking reel on the first rakes, which were put on the market under the name FORTUNA, was patented in 1947 by Felice REPOSSI. This device is still in use on the machines manufactured today.
Because it is a renewable and environmentally friendly energy source, horse traction is currently undergoing a renaissance in small scale agricultural holdings, winegrowing, market gardening and forestry. Within this context, implements for animal traction with mechanical drivetrain are gaining importance. One of the goals of the non-profit association Schaff mat Päerd is to support this process by the development of new equipment and related studies and publications.
This test report, as well as the comparative report SmP 2013-2, analyzes the possible range of use of the ground driven hay rakes available on the European market for horse traction. Because the topographic, economic and social situations in much of the world do not favor big hitches, this report focuses on a single animal hitch.
Materials and methods
The comparative test of the two rakes from MAINARDI A. s.r.l. and REPOSSI Macchine Agricole s.r.l. took place on July 27, 2013, under attendance of Mr. Renato PELLEGRINI and Mr. Francesco REPOSSI (representing the company REPOSSI Macchine Agricole s.r.l.) and Mr. Gabriele ORNATI (representing the company MAINARDI A. s.r.l.). The machine used from the manufacturer REPOSSI Macchine Agricole s.r.l. was the type 68/5 (model 2006). Considering the fact that this manufacturer actually offers no machines which are equipped for horse traction as standard, the test series also served to demonstrate the application of the new forecart prototype SmP Mono-Rad 1.0 for this kind of agricultural works. The technical characteristics of this forecart can be found on the webpage www.schaffmatpaerd.org. Furthermore, a seat with mechanical spring suspension developed by SmP, as well as a lines holder, which can be fixed by clamps on the main frame of the rake (without modifications on the standard equipment), were examined during the test.
To evaluate the required tractive effort, the draft force and the working speed were measured during different works. These were:
-the windrow inverting
-the single windrowing
-the double windrowing
The implement, especially the working height, was adjusted as specified by the manufacturer in order to get a clean raking without ground contact of the teeth. All measurements were taken between 09.00 and 12.00 a.m. The forage of the 3rd cut, which was mown the previous day, was located on the following two parcels with flat and hard soil:
-Parcel A with a surface of 0.7 ha and a specific yield mass between 0.30 and 0.40 kg/m2
-Parcel B with a surface of 0.82 ha and a specific yield mass between 0.80 and 0.90 kg/m2
The measuring device consisted of the following components:
-a Lorenz K-12 force sensor mounted between the single tree and the adjustable traction device on the SmP Mono-Rad 1.0 forecart
-an AHLBORN FUA9192 speed sensor with optical scanning of an impulse disc mounted on the wheel of the SmP Mono-Rad 1.0 forecart
-an AHLBORN Almemo 2690-8 data logger with memory connector and micro SD card mounted on the main frame of the REPOSSI 68/5 rake
As well as the tractive effort generated by the single hitched horse, the working principle and results for the different operating modes of the machine were examined. The connection between the evener and the double-stitched leather traces, with inner webbed nylon reinforcement, was achieved for the first test series using draft springs from the Italian manufacturer EQUI IDEA with a spring rate of 17.5 N/mm, mounted on both sides. The same horse, of the Comtois (FR) breed named Tenor, 6 years old and belonging to the MOSCARDO farm, was hitched for each measurement. The angle of draft was set identically on both tested machines with a single tree height of 380 mm.
In order to guarantee the statistical significance of the measurements, the different works were executed repeatedly, this with a total measurement time between 04 min 05 s and 11 min 11 s. The measured values were recorded with a summary measuring rate of 100 Hz resulting in a frequency of 33.33 Hz for each of the three dimensions (time, force, speed).
The graph 1.1 shows a very small draft power for the single windrowing. Within this context an advantage can be accorded to the REPOSSI 68/5 rake compared to the MAINARDI 268 rake, which was also part of this comparison test (see graph 3), as second-mentioned required 30-47% more draft force, despite a smaller working width and a slightly smaller weight. This difference in the draft force requirements in favor of the REPOSSI rake can be accounted for by the bigger rear wheels on the 68/5 model and thus a lower rolling friction coefficient as well as a better mechanical efficiency of the transmission, which consists of a single bevel gear in an oil bath. Furthermore, the REPOSSI 68/5 rake has 5 raking bars, whereas the MAINARDI 268 rake is fitted with just 4 bars. This reduces the specific yield mass, which has to be lifted from the ground and transported to the side and by that the irregularity of the needed drive torque. Compared to the REPOSSI 68/4 model with just 4 raking bars, the version with 5 bars also has a lower gear ratio between the drive wheels and the raking reel and offers by that a higher drive torque at the raking reel.
Graphs 1.1 and 2.1 shows that the windrowing of parcel B, with a higher moisture content compared to parcel A, required more effort for the horse. For the average value of the draft force an increase of 156% could be determined. With the growth of the effort, the irregularity of the draft force increases, represented by the mean deviation. Nevertheless both tests can be considered as light work for the horse. The fatigue of the horse at the end of the trials, which could be noted by a decrease of the working speed, resulted mainly from the high ambient temperature and the mental stress, which was caused by the separation from the other horses during the duration of the test.
A comparison of graphs 2.1 and 2.2 shows that the use of draft springs effects a reduction of the draft force compared to the direct draft of the leather traces on the single tree of 7% for the draft force average value and of 14% for the mean deviation of the draft force oscillations. The working results in the raking mode can be assessed as very good, this with a mild treatment of the forage. As the yield mass was relatively small, a twist of the hay in too tight swathes could not be determined. Thanks to a low circumferential speed of the raking reel and the short distance which the hay travels in a straight line on the ground, it can be assumed that the hay quality is less negatively affected as on rotary rakes, which work with a higher speed on a half circle.
By comparison of the graphs 1.1 and 1.2 it can be concluded that the tedding requires a slightly higher effort than the raking, with an increase of 8% for the average value of the draft force. The pronounced difference between the two measurements in the movement irregularity of the hitch, was caused by the nervousness of the horse at the beginning of the measurements and not by the change of the operating mode of the machine.
For the tedding, the results of the rake REPOSSI 68/5 are less satisfying as for the MAINARDI 268 rake, which increases the speed of the raking reel in this operating mode, whereas the REPOSSI 68/5 machine just changes the direction of rotation of the reel. In this context it should be mentioned that this operating mode delivers satisfying working results on both tested machines, if the swathes present a low size.
The machine made little noise during work. The communication between the man and the animal was not affected negatively. Sitting at the rear of the machine affords the driver a good view on the function of the machine, but requires rather long lines, which have to be supported by a lines holder in the center of the machine. This detracted from the preferred direct contact with the horse.
The working height can be adjusted precisely via a spring assisted lever with toothed segment, by the driver. Compared to the MAINARDI 268 rake, the raising of the raking reel requires more effort as an assist by a pedal is missing. For engaging the machine, respectively changing the direction of rotation, the carter has to dismount from the seat as the lever is situated out of reach. The double claw clutch on the output shaft of the gearbox needs just a small actuating force. The inclination of the raking reel can be varied by an adjusting screw in the lifting mechanism, which needs the use of a wrench.
The SmP Mono-Rad 1.0 forecart is allowed to adapt the height, the length and the width of the shafts as well as the height of the single tree to the horse’s size. The small wheel load of the forecart as well as the three-wheel concept required just a small steering effort of the horse. Neither the wheel spokes, nor the brake and pulser discs showed a tendency to coil hay. The seat is easily accessible by the rear and offers a sufficient view of the machine and the horse and, by its spring suspended mounting, an acceptable comfort for the carter. The lines holder, in stainless steel tube, prevents early wear of the lines and at the same time effectively prevents entanglement in the raking reel (this also during maneuvers at the headlands) without influencing too much the commands of the carter by the lines.
The measured data agree absolutely with the values which were determined during earlier tests by SmP in Belgium and Luxembourg with the same type of machine. Even at multiple windrowing, the draft effort of the horse can be classified as light to very light, depending on the moisture content of the crop.
In order to improve the performances at tedding, it would be advantageous to make two smaller windrows, so called night swathes, which could be easier spread.
The three-wheel concept with big rear wheels, which support a large part of the implement weight, in combination with a smaller steerable front wheel, proved to be very favorable for horse traction. This concept is also suitable for other SmP prototypes for seeding, spreading organic manure and haying.
For the use of the SmP Mono-Rad 1.0 forecart on the tested rake, it should be improved by a brake pedal on the seat frame, which would be operated by the right foot to activate the mechanical disc brake of the forecart. This would improve the working comfort of the horse as well as the safety at work. A second pedal, to be operated by the left foot, should be mounted additionally for assisting the lifting of the raking reel. This would improve the safety at work as the right hand could be kept on the lines and the lifting would only be executed by the left hand.
Additional tests must be conducted to determine the effect of rigid and pivoting completely independent shafts, on the SmP Mono-Rad 1.0 forecart on the working comfort of the horse, especially in terms of the support forces of the shafts on the back pad and the steering forces in different working situations. The same applies to a detailed analysis of the impact of the draft springs in the different operating modes. Comparative tests also need to be conducted on hilly terrain.