FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
A SYSTEM FOR CONTROLLED OPERATION OF THREE POINT LINKAGE IN OFF-ROAD VEHICLE SUCH AS TRACTOR
2. APPLICANT(S)
MAHINDRA & MAHINDRA LTD.
GATEWAY BUILDING, APOLLO BUNDER, MUMBAI - 400001, MAHARASHTRA, INDIAN.
The following specification particularly describes the invention and the manner in which it is to be performed.

Field of the Invention
The present invention relates to a system to operate three point linkage / rockshaft to desired and set position in the off-road vehicle such as tractor. In particular, the invention relates to hydraulic and electronic based power lifting system that enables desired controlled lifting or lowering of hitched implement to the three point linkage of the tractor.
Background of the Invention
Off-road vehicles such as tractors or farm machineries such are provided with an arrangement such as three point linkage to attach earth-working implement(s), in the rear end of the vehicle. This linkage is operably linked to the hydraulic power lifting mechanism that operates / rotates so as to lift or lower the implement. The commonly provided controls in tractor hydraulic system are position and draft control.
In field operations, during turning of the tractor at the headland, the implement requires to be raised to clear the ground. The height which it should be raised depends on implement size and ground clearance desired. Lower the height to which the implement is raised, lesser the time for lifting and lowering cycle. Thus the height to which the implement is raised has a direct bearing on productivity. The conventional / state-of-the art off road vehicles such as tractors are not provided with this facility / mechanism.
The need in the market place exists for a mechanism for controlled quick lifting or lowering of the tractor implement to an adjustable height, wherein the operator can pre-set the lifting height of the implement to any desired value, just enough to clear the ground. It is as well desirable to provide adjustable lifting / lowering thus by pre-

setting, the max depth also can be controlled. It is important that this mechanism should not disturb the operation of the already existing said position and draft control.
Summary of the Invention
The main object of the invention is to provide a system for controlled operation of three point linkage to desired and set position in the off-road vehicle such as tractor. Further object of the invention is to provide hydraulic and electronic based power lifting system that enables controlled lifting or lowering of hitched implement to the three point linkage of the tractor.
Another object of the invention is to provide a control system to enable operate the three point linkage so as to lift / lower the hitched implement in a controlled manner.
Yet another object of the invention is to provide a system to adjust extent of lowering / lifting of the implement.
Yet another object of the invention is to provide a system to provide controlled lowering / lifting of the implement of the tractor without affecting functions of the existing position and draft control.
Thus in accordance with the invention the system comprising quick lift sub-assembly, mounting frame, wedge provided on rockshaft, controller, control lever, valve block provided with hydraulic solenoid operated valve/s wherein,
the said sub-assembly comprises of stationary quadrant that is in the form of a cylinder and is adapted to be mounted on the said mounting frame wherein at least two portions are cut so as to form a slot on the

surface of the cylinder wherein each of the said slot is disposed at each of the cylinder ends wherein each of the slot runs partially along the circumference that is it is not of the length of the circumference;
first and second moving quadrant and that are in the form of a substantially circular ring are adapted to be mounted on the surface of the said stationary quadrant with sufficient clearance for possible rotation of the said moving quadrants on the said surface, each of the said moving quadrant is provided with threaded knobs to tighten / loosen the said moving quadrants upon engaging in particular said slots of the said stationary quadrant, at least one limit switch is mounted on each of the said moving quadrant wherein the extent of rotation of the said moving quadrant along the circumference of the said surface of the stationary quadrant is limited / restricted because of the available restrained length of the said slot wherein the said moving quadrants along with the said limit switches are rotated on the said stationary quadrant to adjust desired position of the limit switches with respect to each other wherein,
the said quick lift sub-assembly is mounted on a mounting frame that comprises of a base plate provided with at least two vertical members distanced apart and disposed at one of the ends of the said base plate wherein each of the said member is provided with circular openings dimensioned to rotatably receive rockshaft, one of the opening on the member is provided with a cylindrical protrusion facing towards the other member so as to mount the said stationary quadrant wherein,
the wedge is provided on rockshaft and is disposed to be in the proximity of the said limit switch of the said quick lift sub-assembly so that the wedge could activate the said limit switch upon rotation of the said rockshaft by particular angle wherein,

the said valve block and the solenoid operated hydraulic valve is hydraulically connected to the cylinder of the rockshaft assembly wherein,
the said control lever is provided with visual indicators and means to initiate signal for lifting or lowering action wherein the said means is configured with the said controller wherein,
the said controller is configured with the said solenoid operated hydraulic valve of the valve block, the control lever and the said switches wherein,
in operation, upon receiving signal from the said control lever about lifting / lowering the said controller sends signal to the said valve block to operate the said solenoid to initiate hydraulic fluid flow to the said cylinder to initiate rotation of the rockshaft thereby resulting in lifting / lowering of the attached implement, during rotation of the rockshaft at a particular position, the mounted wedge reaches in line with the preset position of the said switch of the said sub-assembly resulting in activation of the said switch that send signal to the said valve block to stop the hydraulic fluid flow to the said cylinder to cease the action of lifting / lowering thereby enabling controlled quick lifting or lowering of hitched implement based on pre-set values.
Description of the Invention
Features and advantages of this invention will become apparent in the following detailed description and the preferred embodiments with reference to the accompanying drawings.
Figure 1 Schematic of the System (Sheet 1)
Figure 2 Schematic of the quick lift sub-assembly mounting

(Sheet 1) Figure 3 Schematic of the quick lift sub-assembly (Sheet 2) Figure 4 Schematic of the operational aspect of the sub-assembly
(Sheet 2)
Figure 1 illustrates system configuration, it comprises of quick lift subassembly 2, mounting frame 6, wedge 15 provided on rockshaft assembly 7, controller 16, control lever 1 and the valve block 20 provided with hydraulic solenoid operated valve/s 17. The valve block 20 is hydraulically configured with the cylinder 8 of the rockshaft assembly. Further, the solenoid valve 17 is electronically configured with the microprocessor based controller 16. The control lever 1 comprises of a ergonomically profiled handle on which buttons are provided for "quick lifting" and "quick lowering", those are configured with the controller 16. The said rockshaft assembly comprises of cylinder 8 provided with ports 18 and 19.
As illustrated in Figure 2, the said quick lift sub-assembly 2 is mounted on the mounting frame 6 that comprises of a base plate 25 provided with at least two vertical members 26 & 27 distanced apart and disposed at one of the ends 28 of the said base plate 25. Each of the said members is provided with bored holes 29 & 30 dimensioned to rotatably receive rockshaft 7. One of the openings 29 on the member 26 is provided with a cylindrical protrusion 31 facing towards the other member 27 so as to mount a stationary quadrant of the sub assembly 2.
Figure 3 illustrates the said quick lift sub-assembly 2. It comprises of the stationary quadrant 3, that is in the form of a cylinder. It is adapted to be mounted on the said mounting frame 6. At least two portions / segments 9 &10 are cut so as to form a slot on the cylinder surface. Each of the said slots is disposed at each of the cylinder ends

36 and 37 as illustrated in the Figure 3. Each of the slots runs partially along the circumference that is the slot is not of the length of the circumference. The first and second moving quadrant 4 and 5 that are in the form of a substantially circular ring are adapted to be mounted on the surface of the said stationary quadrant 3 with sufficient clearance for possible rotation of the said moving quadrants on the said cylinder surface of the stationary quadrant 3.
Each of the said moving quadrants 4 & 5 is provided with threaded knobs 13 & 14 to tighten / loosen the said moving quadrants upon engaging in particular said slots of the said stationary quadrant. At least one limit switch 11 & 12 is mounted on each of the said moving quadrant wherein the extent of rotation of the said moving quadrant along the circumference of the said cylinder surface of the stationary quadrant is limited / restricted because of the available restrained length of the said slot. The said moving quadrants along with the said limit switches are rotated on the said stationary quadrant 3 to adjust desired position of the limit switches with respect to each other.
As illustrated in Figure 4, the wedge 15 is provided on rockshaft 7 and is disposed to be in the proximity of the said limit switch of the said quick lift sub-assembly so that the wedge could activate the said limit switches 11 & 12 upon rotation of the said rockshaft by particular angle as indicated in Figure 4.
In operation, upon receiving signal from the said control lever 1 about lifting / lowering the said microprocessor based controller 16 sends signal to the said valve block 20 to operate the said solenoid valve 17 to initiate hydraulic fluid flow to the said cylinder 8 to initiate rotation of the rockshaft 7 (thereby resulting in lifting / lowering of the attached implement). During rotation of the rockshaft 7 at a particular position, the mounted wedge 15 reaches in line with the pre-set position (as indicated in Figure4a) of the said switch of the said sub-assembly

resulting in activation of the said switch that send signal to the said valve block 20 to stop the hydraulic fluid flow to the said cylinder to cease the action of rockshaft rotation (and thereby lifting / lowering). Thus the desired control lift / lowering as per preset values is possible due to the integration of the operations of the said cylinder, quick-lift sub assembly and controller.
Thus it is evident from the present invention that the synergistic hydraulic and electronic combination and configuration of the said quick-lift sub-assembly, valve block, cylinder assembled with the rockshaft and the control lever working in tandem with each other enables the operator to set and select extent of rotation of the rockshaft enabling quick implement lifting / lowering by desired extent just enough to clear ground in the field resulting in productivity / utilization enhancement of the off-road vehicle such as tractor.

We claim:
1. A system for controlled operation of three point linkage comprising quick lift sub-assembly (2) mounted on a mounting frame (6), wedge (15) provided on rockshaft assembly, controller (16), control lever (1) and a valve block (20) provided with hydraulic solenoid operated valve/s (17) wherein the said rockshaft assembly comprises of the wedge (15), cylinder (8) provided with ports (18 and 19) wherein,
the valve block (20) is hydraulically configured with the cylinder (8) of the rockshaft assembly; the solenoid valve (17) is electronically configured with the controller (16); the control lever (1) is electronically configured with the said controller (16) to enable controlled quick lifting or lowering of hitched implement based on pre-set values in an off-road vehicle such as tractor.
2. A system for controlled operation of three point linkage as claimed in claim 1 wherein the said quick lift sub-assembly (2) comprising stationary quadrant (3) that is in the form of a cylinder and is adapted to be mounted on the said mounting frame (6) wherein at least two portions (9 &10) are cut so as to form a slot on the surface of the cylinder wherein each of the said slot is disposed at each of the cylinder ends (36 & 37) wherein each of the slot runs partially along the circumference that is it is not of the length of the circumference;
first and second moving quadrant (4&5) and that are in the form of a substantially circular ring are adapted to be mounted on the surface of the said stationary quadrant (3) with sufficient clearance for possible rotation of the said moving quadrants on

the said surface, each of the said moving quadrant is provided with threaded knobs (13 &14) to tighten / loosen the said moving quadrants upon engaging in particular said slots of the said stationary quadrant, at least one limit switch (11 & 12) is mounted on each of the said moving quadrant wherein the extent of rotation of the said moving quadrant along the circumference of the said surface of the stationary quadrant is limited because of the available restrained length of the said slot wherein the said moving quadrants along with the said limit switches are rotated on the said stationary quadrant (3) to adjust desired position of the limit switches with respect to each other.
3. A system for controlled operation of three point linkage as claimed in claims 1-2 wherein the said mounting frame (6) comprises of a base plate (25) provided with at least two vertical members (26 & 27) distanced apart and disposed at one of the ends (28) of the said base plate wherein each of the said member is provided with circular openings (29 & 30) dimensioned to rotatably receive rockshaft (7), one of the openings (29) on the member (26) is provided with a cylindrical protrusion (31) facing towards the other member (27) so as to mount the said stationary quadrant.
4. A system for controlled operation of three point linkage as claimed in claims 1-3 wherein the wedge (15) is provided on rockshaft (7) and is disposed in the proximity of the said limit switch of the said quick lift sub-assembly so that the wedge could activate the said limit switch upon rotation of the said rockshaft by particular angle.

5. A system for controlled operation of three point linkage as claimed in claim 1 wherein the said control lever (1) is provided with a ergonomically profiled handle that comprises of visual indicators and means to initiate signal for lifting or lowering action wherein the said means is configured with the said controller.
6. A system for controlled operation of three point linkage as claimed in claims 1-5 wherein system operates upon receiving signal from the said control lever (1) about lifting / lowering the said controller (16) sends signal to the said valve block (20) to operate the said solenoid valve (17) to initiate hydraulic fluid flow to the said cylinder (8) to initiate rotation of the rockshaft (7) thereby resulting in fffting / lowering of the attached implement; during rotation of the rockshaft (7) at a particular position, the mounted wedge (15) reaches in line with the pre-set position of the said switch of the said sub-assembly resulting in activation of the said switch that send signal to the said valve block (20) to stop the hydraulic fluid flow to the said cylinder to cease the action of lifting / lowering thereby enabling controlled quick lifting or lowering of hitched implement based on pre-set values.
7. A system for controlled operation of three point linkage wherein quick lift sub-assembly (2) comprises of stationary quadrant (3) that is in the form of a cylinder and is adapted to be mounted on the said mounting frame (6) wherein at least two portions (9 &10) are cut so as to form a slot on the surface of the cylinder wherein each of the said slot is disposed at each of the cylinder ends (36 & 37) wherein each of the slot runs partially along the circumference that is it is not of the length of the circumference;

first and second moving quadrant (4&5) and that are in the form of a substantially circular ring are adapted to be mounted on the surface of the said stationary quadrant (3) with sufficient clearance for possible rotation of the said moving quadrants on the said surface, each of the said moving quadrant is provided with threaded knobs (13 &14) to tighten / loosen the said moving quadrants upon engaging in particular said slots of the said stationary quadrant, at least one limit switch (11 & 12) is mounted on each of the said moving quadrant wherein the extent of rotation of the said moving quadrant along the circumference of the said surface of the stationary quadrant is limited because of the available restrained length of the said slot wherein the said moving quadrants along with the said limit switches are rotated on the said stationary quadrant (3) to adjust desired position of the limit switches with respect to each other wherein,
the said mounting frame (6) comprises of a base plate (25) provided with at least two vertical members (26 & 27) distanced apart and disposed at one of the ends (28) of the said base plate wherein each of the said member is provided with circular openings (29 & 30) dimensioned to rotatably receive rockshaft (7), one of the openings (29) on the member (26) is provided with a cylindrical protrusion (31) facing towards the other member (27) so as to mount the said stationary quadrant wherein,
the wedge (15) is provided on rockshaft (7) and is disposed in the proximity of the said limit switch of the said quick lift subassembly so that the wedge could activate the said limit switch upon rotation of the said rockshaft by particular angle.