Claims:WE CLAIM:
1. An auto-levelling three point linkage control system (170) in a tractor, wherein said three point linkage (TPL) control system (170) comprising:
• at least one lower link (130) configured to be pivotally attached with a transmission housing (20) of the tractor;
• at least one lift arm (60) pivotally attached on a lift housing (10) of the tractor;
• at least one lift rod (110, 120) connected between the free ends of said lift arms (60) and the central portion of corresponding lower link (130); and
• a top link (100) pivotally connected on said lift housing (10), configured to actuate hydraulically;
wherein, said three point linkage (TPL) system (170) is characterized in that:
o at least one angle sensor (70) is provided in said lift arm (60) and configured to sense the angular position of said lift arm (60);
o at least one sensor (80) provided in said top link (100) for measuring the orientation of said top link (100); and
o wherein said top link (100) is actuated based on a mode of operation as desired by a user, wherein a controller actuates the operation of said top link (100) based on signal received from said position sensor (80) and said angle sensor (70).
2. The auto-levelling three point linkage control system (170) in a tractor as claimed in claim 1, wherein said lift arm (60) is configured to raise and lower said lift rod (110, 120) and thereby said lower link (130);
3. The auto-levelling three point linkage control system (170) in a tractor as claimed in claim 1, wherein a bell crank (150) is externally connected with said lift housing (10), and configured with a plurality of holes (160) to connect said top link (100) at varying depth.

4. The auto-levelling three point linkage control system (170) in a tractor as claimed in claim 1, wherein said sensor (80) is a position sensor configured to sense a change in length of said top link (100) and to sense said top link (100) orientation.
5. The auto-levelling three point linkage control system (170) in a tractor as claimed in claim 4, wherein said angle sensor (70) is a rotary potentiometer and said position sensor (80) is a linear potentiometer and a linear variable differential transducer (LVDT).
6. The auto-levelling three point linkage control system (170) in a tractor as claimed in claim 1, wherein actuation of said hydraulically operated top link (100) is based on three different modes of operation as selected by said user, wherein said operation mode changes the mast angle and an implement ground clearance by adjusting the length of said top link (100) based on the requirement of said user.
7. The auto-levelling three point linkage control system (170) in a tractor as claimed in claim 6, wherein said operation mode is a transportation in which said top link (100) automatically retract its length to a minimum length and thereby improves said mast angle and increases said implement ground clearance.
8. The auto-levelling three point linkage control system (170) in a tractor as claimed in claim 6, wherein said operation mode is a lifting in which said top link (100) gets actuated based on position of said lower link (130) and wherein said top link (100) is automatically adjusted to maintain maximum lifting load throughout the movement range and thereby maintain the mast vertical.
9. The auto- levelling three point linkage control system (170) in a tractor as claimed in claim 6, wherein said operation mode is a manual in which the length of said top link (100) is manually adjusted based on the implement and depth requirement as desired by said user.

10. The auto-levelling three point linkage control system (170) in a tractor as claimed in claim 1, wherein said user is an individual belong to the group consisting of farmers, drivers, and operators.

Dated on 12th day of November, 2021

MOHAN RAJKUMAR DEWAN, IN/PA - 25
Of R.K. DEWAN & CO.
Authorized Agent of Applicant,

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT CHENNAI

, Description:FIELD
In particular, this disclosure relates to an implement actuation system in a tractor. More specifically, it relates to an automatic actuation of a top link of a three-point linkage (TPL) control system in the tractor to maximize tractor lifting capacity.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
TOP LINK: The term "Top link" hereinafter refers to a basic component of a hitch system which connects the different types of implements to a tractor and thereby, transferring the hitching forces of the tractor to the implement or from implement to the tractor. It is also known as upper hitch point. Lower link is similar in functioning as the top link, only it is located below the top link to hold and support the implements. It is also known as lower hitch point.
LIFT LINK: The term “lift link” hereinafter refers to a link which lifts the implements and support the implement in transport position. It provides lateral stability and lateral levelling to the implement.
LIFT ARM: The term “lift arm” hereafter refers to a link which provides necessary force and motion to the lift link. It also provide lateral stability and supports to the implements in transport position.
FRAME LIFT CAPACITY: The term "frame lift capacity" hereinafter refers to a as the minimum load that can be lifted at a point 610mm to the rear of the hitch points in a frame attached to a three-point linkage (TPL).
MAST HEIGHT: The term “mast height” hereinafter refers to a vertical distance between the upper hitch point and the common axis of the lower hitch points.
MAST ANGLE: The term "mast angle" hereinafter refers to an angle defined by a plane passing through the upper hitch point and the lower hitch points with respect to a vertical plane.
HITCH LIFT CAPACITY: The term "hitch lift capacity" refers to a minimum load that can be lifted at hitch point for full power range of a tractor.
The above definitions are in addition to those expressed in the art.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Generally, in a tractor, a hydraulics system is configured to control the various implements mounted on the three-point linkage, implement transportation, lifting of weights and to provide hydraulic power assistance to external or internal systems. Widely, the tractor hydraulic system is used to lift the weight to a maximum possible height and to provide maximum implement ground clearance while transportation. The lift capacity of the tractor frame varies as a lower link moves from a full lowered position to a fully raised condition. Further, while working with heavy or bigger implements, it is required to have more implement ground clearance during transport condition.
However, in conventional practice, the operator intervention is required to operate the three-point linkage so as to lift the load to a maximum possible height as well as to obtain the maximum implement ground clearance. Also, the same manual intervention is required while resuming the work. Therefore, the manual operation of the three-point linkage requires significant amount of time and skill.
Further, while transporting on road or crossing one field to another, it is required to reduce the length of both, .i.e. the lift rod as well as a top link so as to tilt the implement from the setting length. But, adjusting the length of the lift rod or the top link is difficult when the implement is heavier or bigger and more over the same must be repeated while resuming the regular operation. Also, if the sufficient ground clearance is not maintained, the implement may damage the cultivated land or furrow and the bunds while crossing one field to another.
Furthermore, it has found that there is a significant difference between a hitch lift capacity and the frame lift capacity, which results in a mechanical leverage loss. The main factors responsible for determining the mechanical leverage loss of the hitch lift capacity at the frame location is a mast angle. However, it is possible to optimize the leverage loss by maintaining the mast in a vertical condition, but presently there is no mechanism to optimize the mast angle to get more frame lift capacity.
Therefore, there exists a need for an actuating system which can control or adjust the length of top link automatically with minimal manual operation, which obviates the aforementioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide an auto-levelling three point linkage (TPL) control system in a tractor.
Another object of the present disclosure is to provide an auto-levelling three point linkage (TPL) control system in a tractor which provides hydraulically actuated top link.
Yet another object of the present disclosure is to provide an auto-levelling three point linkage (TPL) control system in a tractor which minimizes the manual operation.
Still another object of the present disclosure is to provide an auto-levelling three point linkage (TPL) control system in a tractor which minimizes the manual time of operation.
Yet another object of the present disclosure is to provide an auto-levelling three point linkage (TPL) control system in a tractor which provides ease of operation.
Still another object of the present disclosure is to provide an auto-levelling three point linkage (TPL) control system in a tractor which provides smooth controlling of an implement.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages an auto-levelling three point linkage (TPL) control system in a tractor. The three point linkage (TPL) control system comprise at least one lower link configured to be pivotally attached with a transmission housing, at least one lift arm pivotally attached on a lift housing, at least one lift rod connected between the free ends of the lift arms and the central portion of corresponding lower link and a top link pivotally connected on the lift housing. The lift arm is attached with a lift housing which is configured to raise and lower the lift rod, and thereby the attached lower link.
The three point linkage control system is also configured with at least one angle sensor and at least one position sensor. The angle sensor is provided in the lift arm and configured to sense the angular position of the lift arm, whereas the position sensor is provided in the top link which is configured to sense a change in the length of the top link as well as the orientation of the top link. The angle sensor is selected from a group containing a rotary potentiometer and the position sensor is selected from a group containing a linear potentiometer and a linear variable differential transducer (LVDT).
In an embodiment, the top link of the three point linkage control system is actuated based on a mode of operation as desired by a user. A controller is provided which is configured with the desired mode of the operation. On the basis of the desired operation mode, the controller actuates the operation of the top link based on signal received from the position sensor and the angle sensor.
Further, the actuation of the top link is hydraulically controlled by means of a handle or a switch, as desired by the user. The length of the top link is adjusted to a desired length based on the requirement of the user and the selection of the desired mode of operation.
Advantageously, the top link provides the hydraulic power assistance to the three point linkage control system for lifting the weights and an implements to a maximum height. Also, the adjustment in the length of the top link changes the required mast angle and the implement ground clearance. Thus, it maintains the proper ground clearance to the implements while transportation.
In another embodiment, the actuation of the hydraulically operated top link is based on the three different operation modes as selected by the user. While selecting an operation mode as a transportation, the top link automatically retract its length to a minimum length and thereby improves the mast angle and increases the implement ground clearance. The minimum length of the top link is defined as a length based on the mast angle which is derived indirectly from the position sensor of the top link. This mode is useful while crossing one field to another. Further, while selecting an operation mode as a lifting, the top link gets actuated based on the position of the lower link and the top link is automatically adjusted to maintain maximum lifting load throughout the movement range. The lifting mode adjust the length of the top link throughout the lower link lifting range such that to maintain the mast vertical. Furthermore, on selecting an operation mode as a manual, the top link is manually adjusted based on the implement and depth requirement.
In an embodiment, a bell crank is provided, which is pivotally connected with the lift housing and configured to attach the top link. Also, the bell crank is configured with a plurality of holes at varying depth to provide an adjustable height for the connection of the top link.
Advantageously, the height at one end of the top link is varied within a certain limit depending upon the holes available in the bell crank and thereby, the maximum lifting height of the top link and the three point linkage is increased or decreased to a larger extent based on the requirement.
Typically, the user is an individual belong to the group consisting of farmers, drivers, and operators.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
An auto-levelling three point linkage control system in a tractor of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1, 2 and 3 shows an isometric view of an assembly of a three point linkage control system in a tractor in accordance with an embodiment of the present disclosure;
Figure 4 shows an isometric view of an assembly of a top link and a lift arm with a lift housing in a tractor in accordance with an embodiment of the present disclosure;
Figure 5 shows a pictorial representation of controlling of the hydraulically actuated top link as well as angle of a lower link in combination with a position sensor and an angle sensor respectively in a tractor in accordance with an embodiment of the present disclosure;
Figure 6 shows an isometric view of the hydraulically actuated top link in a tractor in accordance with an embodiment of the present disclosure;
Figure 7 and 8 shows an isometric side view and top view respectively assembly of a three point linkage with a transmission housing in a tractor in accordance with an embodiment of the present disclosure; and
Figure 9 shows an isometric view of the hydraulic actuation of the top link in a tractor in accordance with an embodiment of the present disclosure.
LIST OF REFERENCE NUMERALS USED IN DETAILED DESCRIPTION AND DRAWING
10 - Lift housing
20 - Transmission housing
30 - Transmission
40 - Transmission rear housing
50 - Draft control
60 - Lift arm
70 - Angle Sensor
80 - Position Sensor
90 - Pin
100 - Top link
110 - Lift rod right
120 - Lift rod left
130 - Lower link
140 - Hitch point
150 - Bell crank
160 - Hole
170 - Three point linkage control system

DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an”, and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”, “comprising”, “including”, and “having”, are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
When an element is referred to as being “mounted on”, “engaged to”, “connected to”, or “coupled to” another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region or section from another component, region, or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Terms such as “inner”, “outer”, “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
Generally in a tractor, a hydraulics system is used to control the various implements mounted to the three point linkage, implement transportation, lifting of weights to a maximum possible height and to provide hydraulic power assistance to external or internal systems. While working with heavy or bigger implements, it is required to have more implement ground clearance during transport condition.
However, in conventional practice, the operator or user intervention is required to operate the three point linkage in order to maintain the maximum possible height as well as to obtain the maximum implement ground clearance. Therefore, the manual operation requires significant amount of handling time and skill.
Also, while transporting on road or crossing one field to another, it is required to reduce the length of both, .i.e. the lift rod as well as the top link so as to tilt the implement from the setting length. But, adjusting the length of the lift rod or the top link manually is difficult when the implement is heavier or bigger and more over the same must be repeated while resuming the regular operation.
The present disclosure envisages an auto-levelling three point linkage (TPL) control system 170 in a tractor. An embodiment of the present invention will now be described with reference to Figure 1, figure 2 and figure 3. The figure 1, 2 and 3 shows the perspective view of the three point linkage control system 170. The three point linkage control system 170 comprise atleast one lower link 130 configured to be pivotally attached with the transmission housing 20, atleast one lift arm 60 pivotally attached on a lift housing 10, atleast one lift rod 110, 120 connected between the free ends of the lift arms 60 and the central portion of corresponding lower link 130 and a top link 100 pivotally connected on the lift housing 10.
Further, the three point linkage control system 170 is also configured with at least one angle sensor and at least one position sensor as shown in figure 1 and figure 2. The angle sensor 70 is provided in the lift arm 60 and configured to sense the angular position of the lift arm 60, whereas the position sensor 80 is provided in the top link 100 and configured to sense a change in length of the top link 100 as well as to sense the orientation of the top link. However, a different arrangements can be made depending upon the user requirement, to measure the angle of the top link 100 as per the present disclosure.
In an embodiment, the angle sensor 70 is selected from a group consisting a rotary potentiometer whereas the position sensor 80 is selected from a group consisting a linear potentiometer or a linear variable differential transducer (LVDT).
Also, the lift arm 60 is attached with the lift housing 10 which is configured to raise and lower the lift rod 110, 120 as indicated in figure 4. The motion of the lift arm 60 is transferred to the lower link 130 by means of the attached lift rod 110, 120 respectively.
In another embodiment, the top link 100 of the three point linkage system 170 is actuated based on selection of a mode of operation as desired by a user. A controller is provided, which is configured with the desired operation mode as indicated in figure 5. On the basis of selection of the desired operation mode, the controller actuates the operation of the top link 100 based on signal received from the position sensor 80 and the angle sensor 70.
Further, the actuation of the top link 100 is hydraulically controlled as indicated in figure 5 and figure 6. The length of the top link 100 is adjusted to a desired length based on the requirement of the user and the selection of the desired mode of the operation.
In a preferred embodiment, the actuation of the hydraulic system associated with the top link 100 and the three point linkage system 170 are controlled by means of a handle or a lever or a push-button switch.
Advantageously, the top link 100 provides the hydraulic power assistance to the three point linkage control system 170 for lifting the weights and implements to a maximum height. Also, the adjustment in the length of the top link 100 changes the required mast angle and an implement ground clearance as indicated in figure 7 and figure 8. Thus, it maintains the proper ground clearance to the implements while transportation as well as crossing one field to another field.
The top-link system of the present disclosure reduces human intervention for mast angle adjustment for ground clearance and depth adjustment while in working condition.
By auto-adjusting the top link length and thereby implement height, the manual adjustment time is minimized since the tractor is not required to be stopped for manually adjusting the top link length as needed in conventional system.
In an embodiment, the actuation of the hydraulically operated top link is based on the three different operation modes as selected by the user. On selecting an operation mode as a transportation, the top link 100 automatically retract its length to a minimum length. The minimum length of the top link is defined as a length based on the mast angle which is derived indirectly from the position sensor 80 of the top link 100. Thereby, it improves the mast angle and increases the implement ground clearance. This mode is useful, when the tractor is crossing with the attached implements from one field to another.
Further, on selecting an operation mode as a lifting, the top link 100 gets actuated based on the position of the lower link 130, and the top link 100 is automatically adjusted to maintain maximum lifting load throughout the movement range. The lifting mode adjust the length of the top link 100 throughout the lower link 130 lifting range such that to maintain the mast vertical.
Also, while selecting an operation mode as a manual, the top link 100 is manually adjusted by the user based on the implement and depth requirement for different purposes.
In an embodiment, a bell crank 150 is provided, which is externally connected with the lift housing 10 and configured to connect the top link 100. Also, the bell crank 150 is configured with a plurality of holes 160 at varying depth to provide an adjustable height for the connection of the top link 100 as indicated in figure 9.
Advantageously, at one end of the top link 100, the height of the top link 100 is varied within a certain limit depending upon the holes 160 available in the bell crank 150 as shown in figure 9. Thereby, by varying the height of the top link 100 at one end, the maximum lifting height of the top link 100 as well as three point linkage system 170 is varied to a larger extent.
Typically, the user is an individual belong to the group consisting of farmers, drivers, and operators.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of an auto-levelling three point linkage (TPL) control system in a tractor that:
• automatically actuates the hydraulically operated top link based on selection of desired mode of operation;
• requires minimal human intervention;
• provides ease of operation;
• minimizes the manual operation time; and
• provides better controlling and handling of the implement.
The foregoing description of the specific embodiments so fully reveals 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.
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.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.