Welcome students. As I explained in my um previous class, that
we talk of the about the other tillage equipments. Now, we will talk of those equipment like
disc plough, cultivator etcetera. Well, disc plough well I have talked of the
disc plough um early in the field. Now, here we can see that the different um
items of, these are 3 points hitch which are connected and the frame, the scrapper, the
furrow wheel and the standard ah um which are connected to each one of the major ones
and concave disc. It is a concave disc which has sharpening,
ah very sharpening about chamfered, so that it cuts the soil
Now, types of discs well I have already told in the field itself that the importance of
the disc is in with respect to its line of motion is ah important, where you have the
um disc angle and the tilt angle. So, tilt angle which varies from 15 to 25
degree and the disc angle which varies from 42 to 45 degree, this helps in adjusting the
width of cut and the tilt angle helps in adjusting the depth of curve and generally, these discs
are made of steel and they are in the range of 610 to 710 millimeter in the diameter. These are concave disc and ah disc is beveled
or the chamfering which is given about 2 to 2.5 millimeter for better cutting of the classes
etcetera when it rolls ah while doing operation. Vertical disc, in fact these are implements
which are attached, but they are very much used here. In fact, use about ah um harrows we talk about
harrows and these are the implements which are used in very large equipment, but then
we would like to um show you that these are also there and they are being used with lager
equipments in other parts of the world. Several discs are there and they are connected
at the angles which is the disk angle ranges between 35 to 55 degrees. Disk harrow, well you have seen the operation
of the offset disk harrow. Now, here are some of the disk harrows between
which I want to show you single acting disk harrow. Here the soil is sown on one side and soil
is sown on this side here, the soil is sown on this side, the soil on this side. Now, here the soil um towards this and the
soil is towards this here. So, then case of this you can see the soil
is been sown here, the soil come bit of here and we have shown in the operation of these. Now, how they are connected and what is the
action we will see in later on. Well, disk gang angle as I told you earlier
in case of offset disc which is of varying use. Many attempts of the disc has used in orchards,
sometimes to clear grass as etcetera or to cultivate the land in between the ah crops,
the horticulture crops or the trees which are there. So, it will have a look at this. This is the um angle which is the angle which
is known as normally the gang. Angle which is over 30 to 35 degree which
has seen the center of gravity of this particular implement is over here and this is the hitch
point to the tractor. Now, for single action, one the width of operation
is given by this the offset. In case of the offset type, the width operation
is given by this. In fact, it comes from the geometry of that. This has been calculated from the geometry
of the whole ah implement and then, you should be in a position to use this whenever it is
required for finding out the total force requirement. For tandem ah type, the value is ah something
like this where w is the width of curve, n is the number of disc spacing and s is the
disc spacing in millimeter. This is the diameter of disc in millimeter. So, keeping in view these um units and the
formulae that we have found out, you can find out the total draft requirement. Yes and the problem is given on this particular
offset disc harrow which is a single acting disc. Sorry, calculate the total width of the single
acting disc harrow having ah gang angle 30 degree total number of disc, 14 disc spacing
and disc diameter, where you use this equipment. You have to always think of which particular
ah formula to be used and what are the units because if you do not get the units right,
definitely you are not going to get the correct answer for this. So, if you use this um width here, you can
get the value about this much, then field capacity can be used with width and the speed
of operation. So, field capacity works about in so much
and if there is another portion which we have said that calculate the volume of the soil
handled per hectare by the harrow at a working depth of 3.5. So, if this depth operation is known, then
you can find out the total volume of soil handled which is about 900 meter and 80 meter
cube per hour. So, accordingly you can find out that this
is the width operation. Now, this is given only to understand. You can better understand the implement and
its accent how it actually feel and what are the forces which are acting according to power
which can be ah um generating or required for operation of these. Forces on disc harrow, well um offset disc
harrow for a offset disc harrow, this is important. We have also made here and I wanted to show
you that when this is the um ah tractor here and in this tractor, well ah one thing which
I would like to show you is the um we know that from here to here is the wheel base and
this to this is known as the wheel tread. This is known as wheel tread. Now, this distance keeps on varying and this
um vary from 48 inches to ah 76 inches. Although this is provide, this provision is
there in all the tractors, but generally farmers are not doing it ah for the simple reason
that they do not have the equipment which are to be used in different root way spacing
of the crops and so, this is not used, but then for the academic ah purpose, I think
it is worth going about this part. Well, so in the um ah disc harrow here we
can see that a pair of disc harrow is over here and we can see that the hitch point is. This is the hitch point through the tractor
and this is one gang and this is another gang. It is offset, this is this point that which
CG is there and some center of the first front gang, it is at a distance of b and the rear
gang at distance of d. Now, the offset if this line is it is which
is in this line, then the force acting is P h. Here P h is the force along the line of pull. Now, P h is horizontal component of pull. Now, this P x in case there is an angle alpha. That means, when there is no side draft, alpha
is equal to 0, but when there is side draft, this P x comes into picture. So, when this side draft ah is not there,
it is simply we can take this P h here and the offset, when side draft is present, this
offset is like this and when side draft is not present, the offset is given by this particular
equation where T is talking of this T should be lateral component of the force side, side
force about front and real gang in case of the torques of T f and T r, this should have
been d. Now, similarly d is the longitudinal distance
between the center of two gangs. This is the distance b over here and D f and
D r are the longitudinal component of force front and rear just talk of the front and
rear now this T this in fact because when this alpha is 0 here, then it should be T
r. So, it will be T r here which is the lateral
component of the force on the rear gang, right. So, this is the mechanics of the forces on
the disc harrow. This is the mechanics of forces on disc harrow
and it will be important that if we take up a problem on this and then, understand. Let us see if you can have . Yes. So, we can have a problem on that and here
um there is no angle. Alpha is not there which was discussed over
there and here itself also this T r. So, we can use the um equation which was given
earlier and we can find out the offset values which is up to this. Now, these um problem will help you to better
understand what is an offset disc harrow. Now, from the academic point of view as well
as when you want to design for a particular um power source or when you want to have a
matching implement design for a particular power source or when you want to have a number
of implements required for large area where certain power sources are already available
and we want to get these to be connected or to be procured for better mechanization of
that a particular farm, then these will be required. This information will be definitely required
for you. Well, cultivator now this is a secondary tillage
implement. You have seen already the operation of this
and in the field the shovels are here. In fact, and where these are the um shovels
which are there when the tool bar is spring tyne cultivator with these are the springs
which are there and the rigid tyne. The rigid tyne which I had shown you in the
case, yeah this is the rigid tyne and this is the spring tyne. Now, duck um foot type of cultivator. Now, here this is sweep type here and this
is known as the shank on which these small shanks. No, these are small tools, cutting tools or
ah shovels or cutting tools are attached. We will see what are the different types of
these because different cultivators have been used for different types of operations, but
then many a times, this cultivator is used for a primary tillage implement. Now, we will have a look at those different
types of these small elements, yes. So, these are the different soil engaging
tools of a cultivator, this is half sweep, full sweep, double point shovel, then a single
point shovel, the furrow type. So, these are the ones which are then only
used on that depending upon the type of the requirement in the shanks of those tools. Well, when a particular type of ah element
is used, what is the soil zone? What is yes . The soil operating um zone of the cultivator you
can see that this is the type . What is the soil zone which will affect? So, you can see that the total soil zone if
these are two consecutive tynes, so the total zone is the distance between this two, this
t 0. This is the distance and this t 0 is given
as t 0 is equal to twice a max plus b 0 plus delta t. So, delta t is the distance, this 2 to 5 centimeter
for the shovels and about 0 to 5 centimeter for the sweep type. Now, this will be important when you want
to find out the total width of the implement with respect to this spacing between 2 tynes
and the b 0 width of the sweep, a maximum depth operation. These are all details which were given over
here. So, this will help you in finding out the
total ah width of the implement when a cultivator with these total operating zone and it is
connected with this small tynes , yes. Another small problem is given which will
help you to understand how we can find the total cultivator. So, opening zone or you can find out the total
width of that furrow which has been operated or which has been cut by small elements which
are connected to the cultivator. The details are given over here. A 9 tyne cultivator, well another problem
which has the similar um values which can be used and you can find out the, you can
find out the t 0 over here and it is very simple problem. Once you go through this, you will be in a
position to put those values and get the answer. Thank you.

Lecture 4:Tractor, implement and soil force consideration for tillage implement design
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One thought on “Lecture 4:Tractor, implement and soil force consideration for tillage implement design

  • September 8, 2018 at 4:15 am

    sir in this formula …… N shoul be replace with N-2


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