Developing the transmission system of the combine cutting device for harvesting rice crop

Abstract

The transmission system of the combine cutting device was developed and manufactured from local material to be suitable for the harvesting operation under Egyptian conditions. Performance evaluation of the combine before and after development during the harvesting operation of rice crop was carried out in terms of grain losses, field capacity , field efficiency, fuel consumption, required power, energy, wearing rate, wearing resistance and cost requirements. The combine performance was studied as a function of change in combine forward speed and grain moisture content and operating time. The results were obtained to gave maximum field capacity, field efficiency, wearing resistance and minimum energy, power, fuel consumption wearing rate, and cost requirements for the two systems of the combine cutting device before and after development as following: 1-It is recommended to used the developed combine. 2-The combine forward speed of about 3.5 km/h. 3-The grain moisture content about 23%.

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FARM MACHINERY AND POWER
Misr J. Ag. Eng., April 2010 426
DEVELOPING THE TRANSMISSION SYSTEM OF THE
COMBINE CUTTING DEVICE FOR HARVESTING
RICE CROP
Helmy M. A.*, T. Z. Fouda**, A. Derbala*** and H. A. Kassem****
ABSTRACT
The transmission system of the combine cutting device was developed and
manufactured from local material to be suitable for the harvesting
operation under Egyptian conditions. Performance evaluation of the
combine before and after development during the harvesting operation of
rice crop was carried out in terms of grain losses, field capacity , field
efficiency, fuel consumption, required power, energy, wearing rate,
wearing resistance and cost requirements. The combine performance was
studied as a function of change in combine forward speed and grain
moisture content and operating time. The results were obtained to gave
maximum field capacity, field efficiency, wearing resistance and minimum
energy, power, fuel consumption wearing rate, and cost requirements for
the two systems of the combine cutting device before and after
development as following:
1- It is recommended to used the developed combine.
2- The combine forward speed of about 3.5 km/h.
3- The grain moisture content about 23%.
INTRODUCTION
ice crop is considered one of the most important foods and export
crops in Egypt. The cultivated area of rice in Egypt is about 1.77
million feddan yearly producing about 7.24 million ton with an
average yield of 4.091 tons/ feddan according to Ministry of Agriculture
statistics (2009) Habib et al. (2001) mentioned that increasing plant stem
diameter need higher knife velocity for performing the free cutting
* Prof., of Agric. Eng., Fac. of Agric., Kafr-elsheikh U.
** Prof., of Agric. Eng., Fac. of Agric., Tanta U.
*** Assoc. Prof., of Agric. Eng., Fac. of Agric., Tanta U.
**** Grad. St. Ag. Mec. Dept., Fac. of Agric., Tanta U.
R
Misr J. Ag. Eng., 27(2): 426 - 437

FARM MACHINERY AND POWER
Misr J. Ag. Eng., April 2010 427
operation. Whereas, increasing mass of plant stalks need low critical
speed. Also, moisture content of plants materials affecting on the critical
knife velocity throwing by the cutting force, where the cutting force
variation with the moisture content. El-Nakib et al. (2003) found that
header, threshing, separating and shoe losses increased with the increase of
the forward speed and the decrease of grain moisture content. The
optimum operating parameters for harvesting rice crop were, combine
forward speed of 4.5 km/h and grain moisture content of 16.5 %.
Badr et al. (2005) indicated that increasing the forward speed from 1.0 to
4.0 km/h at a constant moisture content of 22 %, increased field capacity
from 0.31 to 1.14 fed/h while decreased field efficiency from 89.3 to 82.7
% using Yanmar combine. El- Sharabasy (2006) tested that increasing
machine forward speed from 1.5 to 3.0 km/h increased effective field
capacity from 0.277 to 0.452, 0.251 to 0.382, 0.208 to 0.349 and 0.181 to
0.296 fed/h at different grain moisture contents of 21.45, 22.20, 23.12 and
24.60%, respectively. Fouda and El-tarhuny (2007) studied that the
wearing behavior are affecting by many factor such as composition of
material, hardness, strength, toughness and working time. Also, they added
that increasing working time increased wearing rate. Abdelmotaleb et
al.(2009) showed that the increase of combine forward speed forward 0.8
to 2.5 km/h leads to decrease the field efficiency from 84.96 to 62.35% at
cutting height of 0.2 m by using the combine without control system. The
other cutting heights and combine systems had the same above mention
trend. El-Hanfy et al. (2009) studied that the power consumption for
cutting straw rice was increased with increasing forward speed and cutting
speed. The minimum value of power consumption was (15 kW) noticed at
(0.35 m/sec and 450 rpm) forward and cutting speed respectively.
So one of the serious problems during the harvesting operation were
noticed that the vibration in the transmission system of the combine
cutting device which causes to high wearing rate and break the crank.
-The objectives of the present work are developing the cutting blade
crank of the combine for harvesting rice crop and selecting the combine
optimum conditions. Also estimate the expected life for the cutting blade
crank before and after development.

FARM MACHINERY AND POWER
Misr J. Ag. Eng., April 2010 428
MATERIALS AND METHODS
The main experiments were carried out during seasons 2007 and 2008 at
Bassuen farm, Gharbia Governorate to develop the cutting blade crank on
the Yanmar combine for harvesting rice crop (Sakha 101 variety) and
select the optimum conditions (combine forward speed and grain moisture
content) for operating the developed combine.
-Materials :
-The mean values of crop characteristics of rice variety Sakha 101 were plant
height, 92.3 cm, no. of panicles 526.5 / m2 and weight of 1000 grain,
29.18 gm
-Combine harvester (Yanmar), Type (CA- 385 EG. Japan), output power
hp/rpm, 35/2800 and engine vertical, water cooled 4-cyclediese.
-Methods:
The experiments were conducted in an area of 5 feddans at different
forward speeds of 2, 2.5, 3.5 and 5 km/h and grain moisture contents of
15, 20.3, 23 and 25.7% during operating time (250, 500, 750 and 1000
hours) to select the operational optimum operational conditions.
-The combine cutting device: The combine cutting device in the Yanmar
combine is a three dimensional – slider crank six bar mechanism. This
mechanism is used to drive the combine cutters. It consists of crank shaft,
connecting rod (pitman), lever, link and knife. Such problems had been
noticed during the harvesting operation using the ordinary cutting
mechanism. By many observation, it is noticed that the crank shaft of the
cutting mechanism is the source of these problems. The wearing rate in
the crank joints is very high, causes high vibration in the whole cutting
mechanism parts that tends to break the crank. For this reason, such core
had been taken to construct, develop and operate another crank taking into
consideration cutting efficiency and crank durability.
- Crank shaft of the cutting mechanism before development.
Crank cutting blade unit was made of hard steel metal, the unit consists
of yoke crank jointed with the rod reap edge crank and at the end there is
a ball connected with arm reaping edge trans the motion to cutting blade.
as shown in Fig 1

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Misr J. Ag. Eng., April 2010 429
- Crank shaft of the cutting mechanism after development.
The developed crank is constructed in such a case to avoid vibration of
the cutting device and to prevent any loss of knife speed. The developed
cutting device has a new design with two flange bearings. The device
consists of holder bearing, bearing ball, nut, Shaft connect, holder bearing
and bearing ball. The design was used to control the knife speeds and
minimize the wearing rate of this part as shown in Fig 2.
Evaluation of the combine performance was carried out taking into
consideration the following indicators:
-Effective field capacity: is the actual average working rate of area and
theoretical field capacity is calculated by multiplying machine forward
speed by the effective working width of the machine.
-Total grain losses: The percentage of total grain losses was calculated
by using the following equation:-
Total grain losses = (pre harvest + header + un cutting + threshing and
cleaning.) losses, (%)
-Required power: To estimate the engine power during harvesting
process, the decrease in fuel level accurately measuring immediately after
each treatment. Hunt equation (1983) was used to estimate the engine
power.
-Wearing rate :was calculated as a removal weight g., or removal area
from cutting device divided by operating time h., or , area m2, or harvest
length km.
-Wearing resistance
was calculated as inverted wearing rate (Kantarc 1982)
-Harvesting cost: The total cost of harvesting operation was estimated
using (Awady, 1982) equation. The criterion cost was estimated by the
following equation :-
Criterion cost/fed. = operating cost + grain losses cost/fed.
)(g.km, rate Wearing
1
)(km.g ,resistance Wearing 1-
1- =

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Misr J. Ag. Eng., April 2010 430
33
10
10
55
10
12
12
Scale
1:1
All
Dim
in
mm
Plane.
R2=27.5
R1=30
R7=11
R8=10
R3=22.5
R4=30
R5=27.5
R6=22.5
1
2
3
4
5
6
16
60
65
812
12
8
20
37
90
10
R1=22.5
R3=20 R4=5
R2= 20
R5=15
R6=7.5
1
2
3
4
5
Fig. 1: Crank of the cutting device before development
Part name S. NO. Part name S. NO.
Pin yoke2 Yoke crank 1
Lock nut4 Joint rod3
Ball rbl5
Fig. 2: Crank of the cutting device after development
Part name S. NO. Part name S. NO.
Bearing ball2 Holder bearing-L 1
Connecting rod4 Nut3
Bearing ball 6 Holder bearing-R 5

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RESULTS AND DISCUSSIONS
-Effect of grain moisture content
The most critical factor causing un-cutting losses is grain moisture
content. Figs. 3 and 4 show the effect of grain moisture content on the
percentage of un-cutting and total losses. The increase of grain moisture
content less than 23.0% leads to increase the un-cutting and total losses.
Also, the increase of grain moisture content more than 23.0% leads to
increase the un-cutting and total losses due to increase un-cutting plants.
Increasing the grain moisture content more than 23.0 up to 25.7%
insignificantly affects the un-cutting and total losses. Therefore the lowest
un-cutting and total losses values were recorded with the rice moisture
content of 23 %. Also, The increase of un-cutting and total losses by
increasing forward speed is due to decrease the cutting efficiency and
increase un-cutting plants.
- Effect of combine forward speed
The effect of forward speed on field capacity and field efficiency shown
in Fig. 5. The results revealed that by increasing of forward speed from 2
to 5 km/h. at a constant grain moisture content of 23% and operating time
of 750 h. the field capacity increased from 0.59 to 1.34 fed/h. and from
0.61 to 1.35 fed/h. before and after cutting device development
respectively. While, increasing forward speed from 2 to 5 km/h. decreased
field efficiency from 85.5 to 77.5% and from 88.4 to 78% under the same
previous conditions. However, the high field efficiency of the modified
combine may be due to higher actual field capacity comparing the original
combine. Power as well as energy requirements are too related to the
combine forward speed. Results show that, power required increased as
the forward speed increased while the vice versa was noticed with energy
requirements as shown in Fig. 6. The results evident that by increasing
forward speed from 2 to5 km/h at a constant grain moisture content 23%
and operating time of 750 h required power increased from 13.62 to14.47
kW and from 13.15 to14.28 kW before and after development
respectively. The increase in required power by increasing combine
forward speed is attributed to the excessive load of plants on the cutter-
bar in the time unit and the high impact of cutter-bar with the plants added
to the excessive load of plants on the other combine devices. Also, by

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Misr J. Ag. Eng., April 2010 432
increasing forward speed from 2 to 5 km/h. energy requirements
decreased from 23.08 to10.80 kW.h/fed and from 21.56 to.10.58
kW.h/fed under the same previous conditions. The decrease in energy
requirements by increasing combine forward speed is attributed to the
increase in field capacity.
- Wearing rate and wearing resistance on cutting device
The effect of operating time on wearing rate and wearing resistance in
combine cutting device before and after development shown in Fig. 7.
Results indicated that by increasing operating time from 250 to 1000 h.
the wearing rate in combine cutting device increased from 0.044 to 0.062
g/h and from 0.03 to 0.04 g/h before and after development respectively.
While the wearing resistance decreased from 79.5 to 56.45 km.g-1 and
from 116.7 to 87.5 km.g-1 at the same condition.
- Harvesting cost :
The effect of combine forward speed on operating and criterion cost
before and after development shown in Fig. 8. Results showed that
increasing forward speed from 2 to 5 km/h at a constant grain moisture
content 23%and operating time of 750h operating cost decreased from
101.64 to 44.78 L.E./fed. and from 98.36 to 44.44 L.E./fed. before and
after development respectively. The higher values of operating cost at
lower forward speed is due to the decrease in combine field capacity.
While by increasing forward speed from 2 to 3.5 km/h the criterion cost
decreased from 214.92 to 198.19 L.E*./fed** and from 201.89 to 175.42
L.E./fed., increase in forward speed from 3.5 to 5 km/h criterion cost will
increase from 198.19 to 215.7 L.E./fed. and from 175.42 to 201.14
L.E./fed under the same previous conditions.
---------------------------------------------------------------------------------------------------------------------
* One American dollar =5.54 Egyptian pound (LE) according to prices of 2010
** One feddan (fed) represents an agricultural area unit in Egypt = 4200.83 m2.

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Fig. 3: Effect of grain moisture content on un-cutting losses under
different forward speeds before and after cutting device development.
Fig. 4: Effect of grain moisture content on total grain losses under
different forward speeds before and after cutting device development.

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Misr J. Ag. Eng., April 2010 434
Fig. 5: Effect of combine forward speed on field capacity and field
efficiency before and after cutting device development.
Fig. 6. Effect of combine forward speed on required power and energy
requirements before and after cutting device development.

FARM MACHINERY AND POWER
Misr J. Ag. Eng., April 2010 435
Fig.7: Effect of operating time on wearing rate in combine cutting device
before and after development.
Fig.8: Effect of combine forward speed on operating and criterion cost
before and after cutting device development.

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Misr J. Ag. Eng., April 2010 436
CONCLUSION
The main results of the present research can be summarized as follows:
-The development of the combine cutting device during harvesting rice
crop gave to maximum field capacity, field efficiency, wearing resistance
and minimum required power, energy, wearing rate and cost
requirements.
-The optimum conditions for operating the combine during harvesting rice
crop, were forward speed of 3.5 km/h., operating time of 750h and rice
grain moisture content of 23%.
REFERENCES
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T. U. Izmir Univ. Turky
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/(.  
             
 %   . / .
         )   . . /
  . . .(%   .
      ) (     
./       )  %   .
*    –  –   
**   –   –  
***    –  –  
****   –  –  –  