FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
AUTOMATIC DEPTH AND DRAFT CONTROL SYSTEM
MOVALIYA RAJESH GANDUBHAI
an Indian National
of Captain Tractors Pvt. Ltd,
106, Royal Complex, Dhebar Road,
Rajkot - 360002, Gujarat, India
Inventor:
MOVALIYA RAJESH GANDUBHAI
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

FIELD OF DISCLOSURE
The present disclosure relates to farm machinery, more particularly, the present disclosure relates to a control system for controlling trailer or agricultural machinery hauled by a tractor or a vehicle used in agriculture or construction.
DEFINITION(S):
The term "draft" used in the specification refers to the amount of pull the farm vehicle experiences due to an implement secured to and trailing the farm vehicle, the "draft" can be adjusted by adjusting the position of the trailing implement.
BACK GROUND
A tractor is a vehicle used in agriculture or construction and is adapted to deliver a high tractive effort (or torque) at slow speeds. The tractor provides power and traction that is generally utilized to mechanize agricultural tasks, especially (and originally) tillage but nowadays a great variety of dedicated agricultural implements, such as sprayers, levelers, cultivators, rotavators, ploughs, furrows and the like, may be towed behind or mounted on the tractor for accomplishing different tasks. Generally, these agricultural implements that are towed by the tractors are mechanized and as such are powered by the tractor itself. However, the agricultural implements that are towed by the tractors, such as the sprayers, tillers levelers, and the like are required to be regularly and precisely controlled for efficient interaction thereof with the ground to be tilled, ploughed or leveled. More specifically, the position or the depth of the agricultural implements towed by the tractors with respect to the ground surface being worked upon by the agricultural implements are required to be regularly

and continuously controlled and inspected based on different ground conditions, so as to improve performance of the agricultural implements and achieve better results.
Further, the draft of the agricultural equipment with respect to the tractor is required to be regularly and continuously controlled and inspected based on changing depth positions of the agricultural implements. The "draft" is the amount of pull the farm vehicle experiences due to an implement secured to and trailing the farm vehicle, the "draft" can be adjusted by adjusting the position of the trailing implement. More specifically, draft means the gripping force experienced by the implement as the ground/land being worked upon grips the implements and restrains implement from working onto the ground. In other words, draft is the resistance, typically, caused by hard land, stones, roots and the like, in the soil (i.e. the ground), which acts against the implement and cause hindrance. This hindrance/resistance increases the load acting on the implement, thereby increasing the load acting on the farm vehicle/tractor that is towing the implement. Accordingly, the tractor consumes more tractor power and results in increased fuel consumption. Hence there is need of a system that regularly and continuously controls the draft.
Most of the conventional agricultural implements towed by the tractors are hydraulically or pneumatically operated. However, the settings of the position of the agricultural implements with respect to the ground and tractor, more particularly, the depth and draft control settings, are based on experience of the operator and are not precise. Further, most of the conventional agricultural implements lack a feedback based control system for efficient and precise control of the agricultural implements with changing ground conditions. More specifically, the conventional agricultural implements towed by the tractors lack means for precisely controlling positioning of the agricultural implements with

respect to the ground being worked on thereby accurately controlling operation of the agricultural implements based on the varying ground conditions. Inefficient control and inappropriate placement of the agricultural implements towed by the tractor with respect to the ground, inappropriate depth and draft setting of the agricultural implements may cause damage to the agricultural implement as well as the tractor to which the agricultural implement is connected. Further, inefficient control and in-appropriate placement of the agricultural implements towed by the tractor with respect to the ground, and inappropriate depth and draft setting of the agricultural implements may cause more power consumption, thereby making the use of mechanized agricultural implements inefficient and uneconomical. Still further, in-accurate positioning of the agricultural implement with respect to the ground being worked upon thereby and inappropriate depth and draft setting of the agricultural implements may cause accidents. Although, system for automatic control for the agricultural implements trailing a tractor or farm vehicle are available, but most of the automatic control systems for controlling the agricultural implements are single lever hydraulic systems that perform depth control of the trailing agricultural implements but fail to perform draft control of the trailing agricultural implements.
Accordingly, there is a need for a double lever system, wherein one lever is used for performing draft control, whereas the other lever is used for performing the depth control of the agricultural implements trailing a tractor or farm vehicle. Furthermore, there is a need for a system that automatically, accurately and sensitively controls positioning of the trailing agricultural implements with respect to different ground conditions for efficient depth and draft setting of the trailing implements with respect to the ground with minimum human intervention, thereby reducing chances of error. Further, there is need for a system for regulating positioning of the agricultural implements mounted on a

tractor or other farm vehicle with respect to the ground being worked on thereby that addresses the problem faced by the conventional hydraulic systems for regulating positioning of the trailing agricultural implements. Still further, there is need for system for controlling positioning of the trailing agricultural implements with respect to different ground conditions that is efficient in operation. Furthermore, there is need for a system for accurately and sensitively controlling positioning of the trailing agricultural implements with respect to different ground conditions that is simple in construction and convenient to manufacture, install and use. Further, there is need for a system for accurately and sensitively controlling positioning of the trailing agricultural implements with respect to different ground conditions that exhibits enhanced flexibility in use as per requirements.
OBJECTS:
Some of the objects of the present disclosure which at least one embodiment is adapted to provide, are described herein below:
It is an object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a depth and draft control system that automatically, accurately and sensitively controls positioning of trailing agricultural implements towed by a farm vehicle at a constant depth, particularly, a tractor.
Still another object of the present disclosure is to provide a depth and draft control system that is compact and occupies less space and accordingly can be

mounted on small sized tractors or farm vehicles for withstanding maximum loading capacity.
Yet another object of the present disclosure is to provide a double lever system that performs both draft control as well as the depth control of the agricultural implements trailing a tractor or farm vehicle thereby preventing the agricultural implements from being damaged.
Another object of the present disclosure is to provide a depth and draft control system for automatic and efficient and easy depth and draft setting of the trailing implements with respect to different ground conditions.
Yet another object of the present disclosure is to provide a depth and draft control system that is a quick feedback response system for efficient and precise control of the agricultural implements with changing ground conditions.
Another object of the present disclosure is to provide a depth and draft control system that eliminates damages caused to the agricultural implements due to in appropriate depth and draft setting of the agricultural implements.
Still another object of the present disclosure is to provide a depth and draft control system that enhances operational life of the agricultural implements towed by the farm vehicle.
Another object of the present disclosure is to provide a depth and draft control system that improves performance of the agricultural implements towed by a farm vehicle.

Yet another object of the present disclosure is to provide a depth and draft control system that is efficient in operation.
Another object of the present disclosure is to provide a depth and draft control system that performs efficient depth and draft setting of the trailing implements with respect to the ground with minimum human intervention.
Still another object of the present disclosure is to provide a depth and draft control system to be used with trailing agricultural implements that is simple in construction and convenient to manufacture, install and use.
Another object of the present disclosure is to provide a depth and draft control system for efficient depth and draft setting of the trailing implements with respect to different ground conditions.
Yet another object of the present disclosure is to provide a depth and draft control system, wherein use thereof prevents over loading of the various elements of the farm vehicle and enhances service life of engine, gearbox, differential, tyres and other essential elements.
Still another object of the present disclosure is to provide a depth and draft control system, wherein use thereof reduces wheel slip, thereby resulting in substantial fuel and power saving.
Another object of the present disclosure is to provide a depth and draft control system that ensures easy driving during cultivation.
Yet another object of the present disclosure is to provide a depth and draft control system that enhances service life of the tractor by efficient load management.

Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure.
SUMMARY
A depth and draft control system is for regulating depth and draft settings of an implement connected to a farm vehicle. The depth and draft control system includes a depth control lever, a draft control lever, a housing, a pressure reducing valve (PRV), and a pair of lift arms. The depth control lever is actuated for facilitating raising, lowering and maintaining the implement at desired position with respect to the ground for defining initial depth setting of the implement. The draft control lever is actuated for regulating a draft setting of the implement with respect to the farm vehicle. The housing includes a linkage assembly, a piston-cylinder, a lift arm shaft. The linkage assembly is functionally coupled to the depth control lever and the draft control lever and is actuated thereby. The lift arm shaft is rotatably supported inside the housing and supports a cam and a bush, wherein the cam is functionally coupled to the linkage assembly to actuate the linkage assembly and the bush is functionally coupled to the piston-cylinder assembly. The pressure reducing valve (PRV) is actuated by the linkage assembly for regulating flow of fluid inside a cylinder of the piston-cylinder assembly. The pair of lift arms, wherein one end of each lift arm connected to either ends of the shaft and other end of each lift arm connected to the implement, the lift arms swivels as the lift arm shaft is rotated by rotation of the bush because of reciprocating movement of the piston of the piston-cylinder assembly, the pair of lift arms defines and maintain initial depth and draft setting of the implement as the depth and draft control levers are actuated to cause actuation of the linkage assembly, which in turn regulates the pressure reducing valve (PRV) for restraining fluid flow in and out of the

piston-cylinder assembly, the lift arms further adapted to swivel as the implement deviates from the initial depth and draft settings due to reactions from the ground due to variation in ground conditions, thereby causing the cam mounted on the lift arm shaft to rotate and cause actuation of the linkage assembly, which in turn regulates the pressure reducing valve (PRV) for permitting fluid flow in and out of the piston-cylinder assembly for restoring the initial depth and draft setting of the implement.
Typically, the depth control lever is manually operated to set initial depth.
Alternatively, the depth control lever is automatically operated to set initial depth.
Typically, the draft control lever is manually operated to set initial draft. Alternatively, the draft control lever is automatically operated to set initial draft. Typically, the piston-cylinder assembly is hydraulically operated. Alternatively, the piston-cylinder assembly is pneumatically operated.
In one embodiment, the depth and draft control system is used for small horsepower farm vehicle.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The disclosure will now be explained in relation to the non limiting accompanying drawings, in which:

Figure 1 illustrates a perspective view of an automatic depth and draft control system for performing efficient depth and draft setting of trailing implements of a tractor in accordance with an embodiment of the present disclosure;
Figure 2 illustrates a schematic representation of the automatic depth and draft control system of Figure 1, illustrating a piston cylinder arrangement and a linkage assembly of the automatic depth and draft control system;
Figure 3 illustrates a schematic representation of the linkage assembly of Figure 2;
Figure 4a illustrates a schematic representation depicting an operating configuration of an implement trailing a farm vehicle, wherein the implement experiences resistance that is equal to the resistance levels corresponding to which setting has been made by the automatic depth and draft control system i.e. the implement is not facing any obstruction or hard patch;
Figure 4b illustrates a schematic representation depicting another operating configuration of an implement trailing the farm vehicle, wherein the implement experiences a resistance that is more than what is corresponding to settings made by the automatic depth and draft control system, i.e. the implement is interacting with obstruction or hard patch;
Figure 4c illustrates a schematic representation depicting still another operating configuration of an implement trailing the farm vehicle, wherein the implement experiences a resistance that is less than what is corresponding to settings made by the automatic depth and draft control system;

Figure 5 illustrates an exploded view depicting connection of the automatic depth and draft control system of Figure 1 with a three point linkage system that is supporting the implement trailing the farm vehicle;
Figure 6 illustrates a schematic representation depicting a position control lever and a draft control lever of the automatic depth and draft control system of Figure 1;
Figure 7 illustrates an exploded view of the depth and draft control system of Figure I; and
Figure 8 illustrates an exploded view of the linkage assembly of the automatic depth and draft control (ADDC) of Figure 1.
DETAILED DESCRIPTION:
The invention will now be described with reference to the accompanying drawings which do not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
An Automatic Depth and Draft Control System (ADDC) 100 involves sensing forces acting on an implement trailing a farm vehicle due to irregular ground conditions and accordingly controlling depth and draft of the implement based on feedback received from the implements. The Automatic Depth and Draft Control System (ADDC) 100 controls and regulates positioning of the implement trailing the farm vehicle with respect to ground and with respect to the farm vehicle based on feedback received from the implements, wherein the feedback is based on interaction of the implement with the ground. The Automatic Depth and Draft Control System (ADDC) is preferably suited for use with small sized farm vehicles, typically small horsepower tractor.
The implement is generally connected to the small sized farm vehicle such as tractor by means of a three point linkage system 150 as shown in Figure 5. More specifically, the three point linkage system 150 supports the implement thereon. The three point linkage system 150 supports the implement at three points 151a, 151b and 151c, wherein the first point 151a connects the operating

top of the implement to the Automatic Depth and Draft Control System (ADDC) 100 of the tractor by means of a top link 151, whereas the two bottom points 151b and 151c connects the two operating bottom portion of the implement to the Automatic Depth and Draft Control System (ADDC) 100 of the tractor by means of the links 152a and 152b and a pair of lift arms 7a and 7b, wherein the links 152a and 152b and the lift arms 7a and 7b are pivotally mounted on a rod 153, connected to the Automatic Depth and Draft Control System (ADDC) 100, thereby connecting the links 152a and 152b with the lift arms 7a and 7b. The three point linkage system 150 used for connecting the implement to the tractor resembles either a triangle or a letter A. The implement is so supported by the three point linkage system 150, that the two bottom links 152a and 152b transfers the forces experienced by the implement based on the interaction of the implement with the ground to the Automatic Depth and Draft Control System (ADDC) 100. The Automatic Depth and Draft Control System (ADDC) senses the condition of the ground to be worked upon by via the agricultural implement trailing the tractor and depending upon the feedback received from the two bottom links 152a and 152b regarding the ground conditions, controls the operation of the Automatic Depth and Draft Control System (ADDC) 100, the Automatic Depth and Draft Control System (ADDC) 100 in turn controls the depth of the implement with respect to the ground and draft of the implement with respect to the tractor. Further, the Automatic Depth and Draft Control System (ADDC) 100 together with three point linkage system 150 controls the depth of the implement with respect to draft of the implement. In one embodiment of the present disclosure, the Automatic Depth and Draft Control System (ADDC) 100 is hydraulically operated i.e. it is an Effective Integrated Hydraulic (EIH) Automatic depth and draft control (ADDC) 100. In accordance with another embodiment, the Automatic Depth and Draft Control System (ADDC) 100 may also be pneumatically actuated.

Figure 1 and Figure 2 of the accompanying drawings respectively illustrates assembled view of the Automatic Depth and Draft Control System 100 for regulating efficient depth and draft setting of trailing implements of a farm vehicle such as a tractor. Typically, the farm vehicle is of small horsepower tractor. The automatic depth and draft control system 100 is actuated by lever "L1" and lever "L2" respectively as illustrated in Figure 3. More specifically, the working depth of soil engaging agricultural implement is controlled by a position control lever "L1" and the draft of soil engaging agricultural implement is controlled by a draft control lever "L2". The position control Lever "L1" and the draft control Lever "L2" are disposed at a location accessible to the tractor operator while the tractor operator is seated on the tractor and is driving the tractor. The position control lever "L1" and the draft control lever "L2" of the Automatic Depth and Draft Control (ADDC) 100 provides accurate and sensitive control of implements so that the implement will not drop below the maximum set depth and draft.
The position and draft control system 100 includes a position control lever "L1", a draft control lever "L2", a housing 01, a pressure reducing valve 23 and a pair of lift arms 7a and 7b.
The position control lever "L1" is actuated for facilitating raising and lowering of the implement with respect to the ground for defining initial depth setting of the implement. Further, the position lever "L1" keeps the implement at any desired height. Furthermore, the position control lever "Ll"adjusts load of implements connected to the tractor while transporting the implements from one place to another. Typically, the position control lever "L1" is actuated during leveling or farming operation wherein the implements are required to be raised or lowered or stationary holding the implements.

In one embodiment of the present disclosure, the position control lever "L1" is manually actuated.
In another embodiment of the present disclosure, the position control lever "L1" is automatically actuated.
The draft control lever "L2" is actuated for regulating the draft setting of the implement with respect to the farm vehicle depending upon various ground condition and kinds of implements used. Further, the draft control lever "L2" controls the depth of the implements. The draft control lever "L2" controls the draft of implement corresponding to depth of the implement; thereby prevent the tractor from being overloaded.
In one embodiment of the present disclosure, the draft control lever "L2" is manually actuated.
In another embodiment of the present disclosure, the draft control lever "L2" is automatically actuated.
The housing 01 receives the various elements of the Automatic depth and Draft Control System 100. The housing 01 generally includes a linkage assembly 200, a piston-cylinder assembly 13a and a lift arm shaft 02.
The linkage assembly 200 is functionally coupled to the position control lever "L1" and the draft control lever "L2" and is actuated by the movement of the position control lever "L1" and the draft control lever "L2". The linkage assembly 200 includes a rod link 101, a spring 102, a pair of guide block 103, a link-8 small 104, a link- 8 big 105, a set of bushes 106 of suitable dimensions, a pair of rollers 107, a plurality of linksl08, 109, 110, a pair of bushes 111 of

suitable dimensions, a link -2 bracket 112, a shaft linkage 113, an oil seal 114 of suitable dimensions, a link-3 bracket 115, a link 4 116, a link bracket top link 117, a guide bush 118, a guide support 119, a plurality of links120, 121, a spring 122, a link control, piston 123, a special bolt small 124, a special bolt big 125, a pair of O-rings 126 of suitable dimensions, a pair of split pins127, a pair of copper washers 128 of suitable dimensions, a plain washer 129 of suitable dimensions, a first set of hexagonal bolts 130, a pair of hexagonal bolts 131, a plurality of hexagonal bolts 132, 133, a M8 hexagonal nut 134, a nylock M5 hexagonal nut 135, and a nylock M6 hexagonal nut 136.
In one embodiment of the present disclosure, the piston-cylinder assembly 13 utilizes a single acting cylinder. The piston-cylinder assembly 13 includes a connecting rod 09, a pair of piston rings 10 (illustrated in figure 7), a second piston ring 11, a piston 12, and a cylinder 13a (all illustrated in figure 7).
The piston 12 moves inside and outside the cylinder 13a, thereby causing a forward stroke and a return stoke respectively. More specifically, in a forward stoke, a fluid, typically oil, is forced inside the cylinder 13a to make the piston 12 move outside the cylinder 13a and in the return stroke, the piston 12 moves inside the cylinder 13a and forces the fluid outside the cylinder 13a. Further, the piston 12 is maintained at a predetermined position to set the depth and draft setting of the implements by maintaining the fluid supply system supplying fluid to the piston cylinder assembly 13 in a neutral configuration in which fluid is neither entering the cylinder 13a nor leaving the cylinder 13a of the piston cylinder assembly 13. More specifically, the pressure reducing valve (PRV) 23 is controlling the flow of fluid inside the cylinder of the piston cylinder assembly 13, thereby holding the piston 12 at defined position.

The lift arm shaft 02 is rotatably supported inside the housing 01 of the Automatic Depth and Draft Control (ADDC) 100. The lift arm shaft 02 supports a cam 04 and a bush 05. The lift arm shaft 02 further supports a hydraulic fork 03, a pair of oil seals 06, a pair of lift arms 7a and 7b, a pair of washers 08, a plurality of spring washers 54, and a pair of hex bolt 60 (all illustrated in Figure 7).
The cam 04 is functionally coupled to the linkage assembly 200 to actuate the linkage assembly 200.
The bush 05 is functionally coupled to piston-cylinder assembly 13.
The housing 01 further includes a gasket housing spring 14, a housing spring 15, a spring 16 for guide top link bracket, a spring top link bracket 17, a bracket top link 18, a pin top link bracket 19, a shaft eccentric big 20, a shaft eccentric small 21, Bracket shaft eccentric small 22, a nipple 24, a trailer pipe 25, a first banjo bolt 26, a male-female valve 27, a dust cap 28, an air breather pipe 29, a second banjo bolt 30, a nipple 31, a hydraulic filter 32, a gasket bottom cover 33 for hydraulic housing, bottom cover 34 for hydraulic housing, an elbow hydraulic 35, a gasket hydraulic housing 36, a cover hydraulic housing 37, a plurality of O-rings 38, 39, 40, 41, 42, 43, 44, 45, a pair of external circlips 46, 47 of suitable dimensions, a plurality of split pins 48, 49, a plurality of copper washers 50, 51 of suitable dimensions, a plain washer 52, a plurality of spring washers 53, 54, a first set of Hex bolts 55, one hex bolt 56, and 57 each, a pair of hex bolts 58, a plurality of hex bolts 59, , a plurality of hex bolts 61, a plurality of alien bolts 62, 63, a CSK head screw 64 with hex socket, a stud 65, a plurality of hex nuts 66, a pair of nylock hexagonal nut 67, and a nylock hexagonal nut 68.

The pressure reducing valve (PRV) 23 is actuated by the linkage assembly 200 for regulating flow of fluid inside the cylinder 13a of the piston-cylinder assembly 13.
The pair of lift arms 7a and 7b, wherein one end 7i and 7ii of each lift arm 7a and 7b respectively is connected to either ends 2a and 2b of the lift arm shaft 02 respectively and other end 7iii and 7iv of each lift arm 7a and 7b is connected to the implement (not shown in Figures). The lift arms 7a and 7b swivels as the lift arm shaft 02 is rotated by rotation of the bush 05 because of reciprocating movement of the piston 12 of the piston-cylinder assembly 13, the pair of lift arms 7a and 7b defines and maintains initial depth and draft setting of the implement as the position control lever "L1" and draft control lever "L2" are actuated to cause actuation of the linkage assembly 200. The linkage assembly 200 which in turn regulates the pressure reducing valve (PRV) 23 for restraining fluid flow in and out of the piston-cylinder assembly 13. The lift arms 7a and 7b further swivels as the implement deviates from the initial depth and draft settings due to reactions from the ground due to variation in ground conditions and thereby causing the cam 04 mounted on the lift arm shaft 02 to rotate and cause actuation of the linkage assembly 200. The actuation of the linkage assembly 200 in turn regulates the pressure reducing valve (PRV) 23 for permitting fluid flow in and out of the piston-cylinder assembly 13 for restoring the initial depth and draft setting of the implement.
The Automatic Depth and Draft Control System (ADDC) 100 is initially set as per requirements, particularly, the initial setting of the implements trailing the farm vehicle, is attained by maintaining the fluid supply system supplying fluid to the piston cylinder assembly 13 in a neutral configuration in which fluid is neither entering the cylinder 13a nor leaving the cylinder 13a of the piston cylinder assembly 13. More specifically, the pressure reducing valve (PRV) 23

is controlling the flow of fluid inside the cylinder 13a of the piston cylinder assembly 13, thereby holding the piston 12 at defined position and as such holding the implements in the desired position. The initial depth and initial draft by positioning the control lever "L1" and the draft control lever "L2" for defining resistance settings of the implements trailing the farm vehicle, wherein the settings depends upon the ground conditions, size and weight of the implement, and the like as illustrated in Figure 4a. In neutral position no fluid flows in or out of the cylinder 13a thereby the piston 12 remains stationary within the cylinder 13a and maintains the lift arm shaft 02, connected to the piston 12 through the bush 05, stationery. The pair of lift arms 7a and 7b is thereby stationery as they are functionally connected to the lift arm shaft 02, thereby holding the implement stationary with respect to the ground and the tractor. Accordingly, the implements connected to the arms are maintained stationery in the desired position.
Thereupon, if the implement experiences more resistance that is resistance more than what is corresponding to settings made by the automatic depth and draft control system 100 because of change in ground condition, typically, if the implement gets in contact with an obstruction such as a hard land, stones, roots and the like, the implement gets lifted up and as the implement gets lifted up, the pair of lift arms 7a and 7b moves up, thereby rotating the lift arm shaft 02. As the lift arm shaft 02 rotates, it moves the piston 12, connected to the lift arm shaft 02, through bush 05, inside the cylinder 13a and simultaneously also causes rotation of the cam 04. The movement of the piston 12 inside the cylinder 13a creates a back pressure that tends to push the fluid out of the cylinder 13a. However, the simultaneous rotation of the cam 04 actuates the linkage assembly 200 that in turn causes actuation of the pressure reducing valve (PRV) 23 that allows the fluid to flow inside the cylinder 13a. As the pressure of fluid flowing inside the cylinder 13a is more than the back pressure

created by the piston 12, the piston 12 instead of moving inside the cylinder 13a moves out of the cylinder 13a that causes rotation of the lift arm shaft 02, through bush 05, thereby defining another depth and draft setting of the implement corresponding to the ground condition changes.
Similarly, if the implement experiences less resistance that is resistance less than what is corresponding to settings made by the automatic depth and draft control system 100 because of change in ground condition, typically, if the implement gets in contact with a soft or marshy land and the like, the implement gets lowered and as the implement gets lowered, the pair of lift arms 7a and 7b gets lowered, thereby rotating the lift arm shaft 02. As the lift arm shaft 02 rotates, it moves the piston 12, connected to the lift arm shaft 02, through bush 05, outside the cylinder 13a and simultaneously also causes rotation of the cam 04. However, the simultaneous rotation of the cam 04 actuates the linkage assembly 200 in such a way that the pressure reducing valve (PRV) 23 is actuated to cause removal of the fluid from the cylinder 13a. This outside movement of the fluid causes movement of the piston 12 and rotation of the lift arm shaft 02, through bush 05, thereby defining another depth and draft setting of the implement corresponding to the ground condition changes.
TECHNICAL ADVANCEMENTS AND ECONOMIC SIGNIFICANCE
The depth and draft control hydraulic system for automatically setting the depth and draft setting of the trailing implements with respect to different ground conditions in accordance with the present disclosure has several technical advantages including but not limited to the realization of:

• a depth and draft control system that automatically, accurately and
sensitively controls positioning of trailing agricultural implements towed by a farm vehicle at a constant depth, particularly, a tractor;
• a depth and draft control system that is compact and occupies less space and accordingly can be mounted on small sized tractors or farm vehicles for withstanding maximum loading capacity;
• a double lever system that performs both draft control as well as the depth
control of the agricultural implements trailing a tractor or farm vehicle thereby preventing the agricultural implements from being damaged;
• a depth and draft control system for automatic and efficient and easy
depth and draft setting of the trailing implements with respect to different ground conditions;
• a depth and draft control system that is a quick feedback response system
for efficient and precise control of the agricultural implements with changing ground conditions;
• a depth and draft control system that eliminates damages caused to the
agricultural implements due to in appropriate depth and draft setting of the agricultural implements;
• a depth and draft control system that enhances operational life of the
agricultural implements towed by the farm vehicle;
• a depth and draft control system that improves performance of the
agricultural implements towed by a farm vehicle;
• a depth and draft control system that is efficient in operation;
• a depth and draft control system that performs efficient depth and draft
setting of the trailing implements with respect to the ground with minimum human intervention;

• a depth and draft control system to be used with trailing agricultural
implements that is simple in construction and convenient to manufacture, install and use;
• a depth and draft control system for efficient depth and draft setting of the trailing implements with respect to different ground conditions;
• a depth and draft control system, wherein use thereof prevents over
loading of the various elements of the farm vehicle and enhances service life of engine, gearbox, differential, tyres and other essential elements;
• a depth and draft control system, wherein use thereof reduces wheel slip, thereby resulting in substantial fuel and power saving;
• a depth and draft control system that ensures easy driving during
cultivation; and
• a depth and draft control system that enhances service life of the tractor
by efficient load management.
Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure.
The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure and the claims unless there is a statement in the specification to the contrary.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

1 Claim:
1. A depth and draft control system for regulating depth and draft settings of an implement connected to a farm vehicle, said depth and draft control system comprising:
o a depth control lever adapted to be actuated for facilitating raising,
lowering and maintaining said implement at desired position with
respect to the ground for defining initial depth setting of said
implement;
o a draft control lever adapted to be actuated for regulating a draft
setting of said implement with respect to said farm vehicle; o a housing comprising:
• a linkage assembly functionally coupled to said depth control lever and said draft control lever and actuated thereby;
• a piston-cylinder assembly; and
• a lift arm shaft rotatably supported inside said housing and adapted to support a cam and a bush, wherein said cam is functionally coupled to said linkage assembly to actuate said linkage assembly and said bush is functionally coupled to said piston-cylinder assembly;
o a pressure reducing valve (PRV) adapted to be actuated by said linkage assembly for regulating flow of fluid inside a cylinder of said piston-cylinder assembly; and
o a pair of lift arms, wherein one end of each lift arm connected to either ends of said shaft and other end of each lift arm connected to said implement , said lift arms adapted to swivel as said lift arm

shaft is rotated by rotation of said bush because of reciprocating movement of said piston of said piston-cylinder assembly, said pair of lift arms adapted to define and maintain initial depth and draft setting of said implement as said depth and draft control levers are actuated to cause actuation of said linkage assembly, which in turn regulates said pressure reducing valve (PRV) for restraining fluid flow in and out of said piston-cylinder assembly, said lift arms further adapted to swivel as the implement deviates from said initial depth and draft settings due to reactions from the ground due to variation in ground conditions, thereby causing said cam mounted on said lift arm shaft to rotate and cause actuation of said linkage assembly, which in turn regulates said pressure reducing valve (PRV) for permitting fluid flow in and out of said piston-cylinder assembly for restoring said initial depth and draft setting of said implement.
2. The depth and draft control system as claimed in claim 1, wherein said depth control lever is manually operated to set initial depth.
3. The depth and draft control system as claimed in claim 1, wherein said depth control lever is automatically operated to set initial depth.
4. The depth and draft control system as claimed in claim 1, wherein said draft control lever is manually operated to set initial draft.
5. The depth and draft control system as claimed in claim 1, wherein said draft control lever is automatically operated to set initial draft.

6. The depth and draft control system as claimed in claim 1, wherein said piston-cylinder assembly is hydraulically operated.
7. The depth and draft control system as claimed in claim 1, wherein said piston-cylinder assembly is pneumatically operated.
8. The depth and draft control system as claimed in claim 1, wherein said depth and draft control system is used for small horsepower farm vehicle.