Title of Invention	A MECHANISM TO LIFT AND LOWER TRACTOR IMPLEMENT TO AN ADJUSTABLE HEIGHT IN ADDITION TO HYDRAULIC POSITION AND DRAFT CONTROLS
Abstract	A mechanism to lift and lower tractor implements, to an adjustable height in addition to conventional hydraulic position and draft control system in a tractor or similar vehicles, with mechanical operating controls. The mechanism is used in combination with existing position and draft controls, especially at headland of the field, to lift the attached implement to an adjustable height without disturbing setting of position and draft controls and lower the same to the preset depth, which was set by the position control and / or draft control. TO THE CONTROLLER OF PATENTS THE PATENT OFFICE, MUMBAI 2 9 MAR 2007

Title of Invention

A MECHANISM TO LIFT AND LOWER TRACTOR IMPLEMENT TO AN ADJUSTABLE HEIGHT IN ADDITION TO HYDRAULIC POSITION AND DRAFT CONTROLS

Abstract

A mechanism to lift and lower tractor implements, to an adjustable height in addition to conventional hydraulic position and draft control system in a tractor or similar vehicles, with mechanical operating controls. The mechanism is used in combination with existing position and draft controls, especially at headland of the field, to lift the attached implement to an adjustable height without disturbing setting of position and draft controls and lower the same to the preset depth, which was set by the position control and / or draft control. TO THE CONTROLLER OF PATENTS THE PATENT OFFICE, MUMBAI 2 9 MAR 2007

Full Text	FORM2 THE PATENTS ACT, 1970 (39 of 1970) and Patent Rules 2003 COMPLETE SPECIFICATION (See section 10; rule 13) 1. Title - A MECHANISM TO LIFT AND LOWER TRACTOR IMPLEMENT TO AN ADJUSTABLE HEIGHT IN ADDITION TO HYDRAULIC POSITION AND DRAFT CONTROLS 2. Applicant - MAHINDRA & MAHINDRA LTD 1, GATEWAY BUILDING, APOLLO BUNDER, MUMBAI -400001. AN INDIAN COMPANY. The following specification particularly describes the nature of this invention and the manner in which it is to be performed. 477/MUM/2006 FIELD OF INVENTION This invention relates to a mechanism to lift a hitched implement to an adjustable height and lower the same to the preset depth, using manual control, in addition to tractor hydraulic position and draft controls. The mechanism can be used, especially at headland, to lift the implement to an adjustable height without disturbing position and draft controls and lower the same to the preset depth, which was set by the position control and/or draft control. BACKGROUND OF THE INVENTION The commonly provided mechanisms in tractor hydraulic systems for lifting and lowering the implement are position and draft control mechanisms, either operated mechanically (lever or push button operated) or through Electro-hydraulic controls (button or rotary switch). Tractors which have hydraulic controls in addition to the position and draft controls, as well as related patents are described below: 1. John Deere 6000 Series In these tractors an electrical switch is provided, as part of an Electro-hydraulic system, for lifting and lowering the implement, in addition to position and draft controls. Manually putting the switch into the ON or OFF position, sends a signal to an electronic control unit, to lift or lower the implement. Being an Electro-hydraulic system, it necessarily requires electronic control unit and sensors. 2. Ford New Holland 3030, 3230, and 3630 In these tractor models manual control is provided to lift an implement to a fixed height and lower the same to the preset depth, in addition to the position and the draft controls. In this mechanism two push buttons are provided, one for lifting & another for lowering. When the lift button is pressed, the motion is transmitted to the spool of the control valve via a linkage arrangement, causing oil flow into the cylinder & subsequent rising of the hitched implement to its maximum height, 2 which is fixed. When the lowering button is pressed, the linkage arrangement moves in the opposite direction, allowing oil flow out of the cylinder & the implement is lowered. The operator cannot adjust the height of the implement rise to any intermediate position below this maximum height, using the above control. 3. Improved Lifting and Lowering System (Patent No. IN 197898) This patent claims a lifting and lowering system, wherein the lifting and lowering operation of implement is made automatic in relation to the vehicle's reverse operation or steering operation by means of electrical sensing. In this mechanism, the lifting and lowering of the implements is achieved through movement of position control lever itself after latching this lever into automatic mode position. Thus this control mechanism is not independent of position control-and to operate the position control, the operator needs to unlatch the position control lever from the automatic mode. 4. 'A push button lift control mechanism for Tractors having mechanically operated hydraulic controls' (Patent Application No. 145/DEL/2Q05) This patent describes a mechanism similar in function to that explained in point no. 2. (Ford New Holland tractor models 3030, 3230, 3630). Here also the operator cannot adjust the lifting height of the implement to any intermediate position below the maximum height. NEED OF THE INVENTION In field operations, during turning of the tractor at the headland, the implement requires to be raised to clear the ground. The height to which it should be raised depends on implement size and the 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. Therefore, a need exists for a mechanism to lift and lower tractor implement to an adjustable height in addition to hydraulic position and draft controls, wherein the operator can pre-set the lifting height of the implement to any desired value, just enough to clear the ground. OBJECTS OF THE INVENTION A primary objective of the present invention is to propose a mechanical control mechanism in addition to tractor hydraulic position and draft control mechanisms, to lift the implement to a pre-set height adjustable by the operator and lower the same to its original position, independent of both position and draft controls. Another objective of this invention is to propose a push button for lift and another push button to lower the implement. A further objective of this invention is to propose a push button control to lift the implement to a height adjusted by the operator and bring the hydraulic system in neutral after the height is achieved. A still further objective of this invention is to propose a push button to lower the implement to a preset depth corresponding to the setting of position and draft controls. BRIEF DESCRIPTION OF THE DRAWINGS For understanding various aspects of this invention, the mechanism will now be explained with the aid of the following drawings ; Figurel: shows existing hydraulic system with position and draft control mechanism Figure2: shows front view of proposed mechanism to lift and lower tractor implement to an adjustable height, in addition to position and draft control 4 mechanism as shown in figure 1. Figure3: shows top view of proposed mechanism to lift and lower tractor implement to an adjustable height in addition, to position and draft control mechanism as shown in figure 1. DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENT The present tractor hydraulic system comprises, a pump (1), supplying pressurizes oil to hydraulic control valve (2) having a spool (31), with a cylinder (3) & piston (4) connected to it. The operation of the spool (31) of the control valve (2) causes the flow of pressurized oil into the cylinder (3), to cause lifting of lift arm (7) & flow of oil out of the cylinder (3), to cause lowering. The piston (4) is connected to the Rocker arm (5) & Rockshaft (6) through a Connecting Rod (10), all of which are fitted inside the hydraulic lift Housing (18). Pair of Lift arms {7) % mounted on either end of the Rockshaft (6). Lift Rod, Lower Links & Top Link constitute various elements of what is described as a 3-point linkage (8), enabling the appropriate attachment of the implement (9) to the tractor. Finally the present tractor hydraulic system contains position controls (29) & draft controls (30), controlling implement lifting / lowering & response to soil force, corresponding to the movement of the position & draft control levers by the operator. The present invention proposes a mechanism in addition to the present position & draft control mechanisms in hydraulic system of tractor or similar vehicle. The various elements of the propose mechanism & their working are described below: The mechanism consists of operating control unit (26) in the form of button / switch mounted on Quadrant Frame (28) of the existing Position & Draft Control mechanism. When the Lifting Control (11) is operated by the operator, it causes rotation of Link external (14). When the operator releases his palm from the Lifting Control (11), it remains in its operated condition by virtue of the Intermediate Crank (13) locking into the upper notch on the metallic insert of Lifting Control (11). Lifting Control (11), Lowering Control (12) & Crank Intermediate (13) are all pivoted on the shanks of the mounting fasteners (32) of operating control unit (26). The Rod Spring Assembly (15), whose one pin is connected at the bottom of the Link External (14). It is the Rod Cross Tube (17), which is transferring the movement (rotation) from the link external (14) to the hydraulic Lift Housing (18), to those elements inside the hydraulic lift housing & for that purpose it is pivoted at either end of the hydraulic lift housing & extends beyond on one side (Right Hand side). On this side Crank External Actuation (16) is attached to the Rod Cross Tube (17). Connecting the Crank External Actuation (16) to the Link External (14) is the Rod Spring Assembly (15), completing the input side of the external mechanism. Inside the hydraulic lift housing (18), the Crank Internal (19) is mounted onto the Rod Cross Tube (17). At the other end of the Crank Internal (19), is connected one end of the Link Internal (20), which receives a back-ward pull. The other end of the Link Internal (20) is attached to the pin at the upper end of Blade Actuating (21). The backward pull to the Link Internal, causes the bottom portion of Blade Actuating (which is pivoted near its center) to press the spool of the control valve (2). This causes the hydraulic control valve (2) to supply pressurized oil to the cylinder (3). The consequent outward movement of the Piston (4) causes the movement of the connecting rod (10), rotation of the Rocker arm (5) & Rockshaft (6) & hence finally the pair of lift arms (7), thus lifting the attached implement (9). This continues until the feedback linkage (23) stops this upward movement of the lift arms (7). For this feedback action to happen, the extended RH side portion of the rod cross tube (17), has another crank called Crank External Feedback (21) fixed to the Rod Cross Tube (17). At the free end of the Crank External Feedback (21) is fitted the pin of the Block Rotary (25), which as the name suggests forms a rotary joint with Crank External Feedback. The feedback is taken externally from the face of the Rockshaft (6), using a fastener called Pivot Rod Adjustable 6 Feedback (22). Finally what connects the Pivot Rod Adjustable Feedback (22) to the Crank External Feedback (21) is an element described as Rod Adjustable Feedback (23). The Rod Adjustable Feedback is hinged on the Pivot Rod Adjustable Feedback & its rod slides into the hole present in the Block Rotary (25) forming a sliding pair. This rod has external threads on which rotate a collar (35) & a lock nut (34). By using this locknut, the collar can be tightened to remain at a particular location on the threaded portion, maintaining a gap between the collar (35) & the Block Rotary (25). This is how the feedback action actually occurs. When the lift arm (7) move upwards corresponding to the operation of lifting control (11), it is followed by rotation of the rockshaft (6) & hence the pivot rod adjustable feedback (22) attached to it. This rotation causes the collar of Rod Adjustable Feedback (23) to come closer towards the Block Rotary (25), finally moving the Block Rotary & through it rotating the Crank External Feedback (21) in the opposite direction to its initial movement. It is this opposite rotation that ultimately causes the spool of the hydraulic control valve (2) that was initially pressed inwards to come back to neutral condition. As the lifting control button is locked in place with intermediate crank. This reverse rotation is absorbed by the spring element of Rod Spring Assembly (15). Oil flow from the hydraulic control valve (2) to the Cylinder (3) stops & thus the pair of Lift Arms (7), which were rising, become steady with the Implement (9) in lifted condition at some "height". This "height" corresponds to the initial gap that was maintained by locking the collar of the Rod Adjustable Feedback (23) at a particular position. Increasing the gap or decreasing this gap by changing the position of locking of the collar (35), causes the angle of lift of implement to correspondingly decrease or increase. This adjustment is located such that it is easily accessible to the operator, who needs to change this lift height based on the size of the bunds in the area of use & based on then size of the implement (9). When tne Lowering Control (12) is pressed down by the operator, it causes the Intermediate Crank (13) to move, thus releasing the Lifting Control (11) till it comes to rest with the Intermediate Crank engaging with the other notch, due to spring action. This causes rotation of the Link external (14) in the opposite direction. The Rod Spring Assembly (15), connected at the bottom of the Link External (14) gets pushed towards the rear, rotating the Rod Cross Tube (17) in the anti-clockwise direction when viewed from the RH side of the hydraulic Lift Housing (18) through the Crank External Actuation (16). This rotation of the Rod Cross Tube causes the forward movement of the Link Internal (20), which receives a forward push. The forward push to the Link Internal, causes the bottom portion of Blade Actuating (21) to move further away from the spool (31) of the hydraulic control valve (2), causing it to work in the lowering mode. The Cylinder (3) gets connected to the reservoir (18) & the Lift Arms (7) will lower the implement (9) to the preset height. We Claim :- 1. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, in a tractor or similar vehicles comprising ; - A lifting control (11) to lift the attached implement (9) to an adjustable height; - A lowering control (12) to lower said implement to the pre-set height. 2. A mechanism to lift and lower implement to an adjustable height, in addition to hydcaulic position and draft controls, as claimed in claim 1, wherein said lifting & lowering controls in turn actuates the spool (31) of the control valve (2) of said position and draft control mechanism by means of External Link (14), Rod Spring Assembly (15), Rod Cross Tube (17), Internal Link (20), Actuating Blade (21) and the like connected in-between said operating controls (11 and 12) and said spool of said control valve wherein ; - when said lifting control is operated, it causes supply of pressurized oil from said control valve to a cylinder (3) causing outward movement of piston (4), thereby achieving rotation of a lift arm (7) and lifting of said implement to an adjustable height, which is attached by means of 3-point linkage mechanism (8) connected to said lift arm ; - when said lowering control is operated, it releases said oil from said cylinder to the reservoir via said spool of said control valve causing inward movement of said piston, thereby achieving lowering of said lift arm & said implement to a pre-set height. 3. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, as claimed in claim 2, wherein ; an adjustable means may be provided in between said rod cross tube and said 9 rockshaft or lift arm so as to cause the lifting movement of said lift arm / implement to an height, adjusted by the operator pased on field requirements. 4. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, as claimed in claim 3, wherein said adjustment means is in the form of turnbuckle (23), which when adjusted maintains the correlation between rotations of said rockshaft & said rod cross tube. 5. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, as claimed in claim 1, wherein said operating controls comprising : - said lifting and lowering controls (11 & 12) are in the form of mechanical switch / button, positioned in an enclosure (26) by means of fasteners (32); - said lifting control, is in turn, connected to said spool of said control valve by means of said External Link, Rod Spring Assembly, Rod Cross Tube, Internal Link, Actuating Blade and finally moving said spool; - Intermediate Crank (13) locking with said lifting control to retain said lifting control to its moved position ; - said lowering control, which moves said Intermediate Crank out of locking with said lifting control, allowing said lifting control to return to its initial position by means of return spring (33). 6. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, as claimed in claim 2, wherein rotation of said rockshaft, causes the collar (35) of Rod Adjustable Feedback (23) to come closer towards and move the Block Rotary (25) & through it rotating the Crank External Feedback (21) in the opposite direction to its initial movement, which ultimately operates said spool of said control valve, that was initially pressed inwards to come back to neutral condition. 7. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, in a tractor or similar vehicles, wherein lifting & lowering controls (11 and 12) in turn actuates spool (31) of the control valve (2) of said position and draft control mechanism by means of External Link (14), Rod Spring Assembly (15), Rod Cross Tube (17), Internal Link (20), Actuating Blade (21) and the like connected in-between said operating controls and said spool of said control valve wherein ; - when said lifting control is operated, it causes supply of pressurize oil from said control valve to a cylinder (3) causing outward movement of piston (4), thereby achieving rotation of a lift arm (7) and lifting of attached implement (9) to an adjustable height, which is attached by means of 3-point linkage mechanism (8) connected to said lift arm ; - when said lowering control is operated, it releases the said oil from said cylinder to the reservoir via said spool of said control valve causing inward movement of said piston, thereby achieving lowering of said lift arm & said implement to a pre-set height; - when said lifting control operates said cross rod tube, rotation of said rockshaft, causes the collar (35) of Rod Adjustable Feedback (23) to come closer towards and move the Block Rotary (25) & through it rotating the Crank External Feedback (21) in the opposite direction to its initial movement, which ultimately operates said spool of said control valve, that was initially pressed inwards to come back to neutral condition. 8. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, as claimed in claim 7 comprising ; said operating controls to lift & lower said implement to an adjustable height & pre-set position respectively ; TO THE CONTROLLER OF PATENTS THE PATENT OFFICE, MUMBAI - said operating controls are in the form of mechanical switch / button, positioned in an enclosure (26) by means of fasteners (32); - lifting control (11), in turn connected to said spool of said control valve by means of said External Link, Rod Spring Assembly, Rod Cross Tube, Internal Link, Actuating Blade and finally moving said spool; - Intermediate Crank (13) locking with said lifting control to retain said lifting control to its moved position; - lowering control (12), which moves said Intermediate Crank out of locking with said lifting control, allowing said lifting control to return to its initial position by means of return spring (33); - adjustment means is in the form of turnbuckle (23), which upon adjustment maintains the correlation between rotations of said rockshaft & said rod cross tube.

Full Text

FORM2
THE PATENTS ACT, 1970
(39 of 1970)
and Patent Rules 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title - A MECHANISM TO LIFT AND LOWER TRACTOR IMPLEMENT
TO AN ADJUSTABLE HEIGHT IN ADDITION TO HYDRAULIC POSITION AND DRAFT CONTROLS
2. Applicant - MAHINDRA & MAHINDRA LTD
1, GATEWAY BUILDING, APOLLO BUNDER, MUMBAI -400001. AN INDIAN COMPANY.
The following specification particularly describes the nature of this invention and the manner in which it is to be performed.
477/MUM/2006

FIELD OF INVENTION
This invention relates to a mechanism to lift a hitched implement to an adjustable height and lower the same to the preset depth, using manual control, in addition to tractor hydraulic position and draft controls. The mechanism can be used, especially at headland, to lift the implement to an adjustable height without disturbing position and draft controls and lower the same to the preset depth, which was set by the position control and/or draft control.
BACKGROUND OF THE INVENTION
The commonly provided mechanisms in tractor hydraulic systems for lifting and lowering the implement are position and draft control mechanisms, either operated mechanically (lever or push button operated) or through Electro-hydraulic controls (button or rotary switch). Tractors which have hydraulic controls in addition to the position and draft controls, as well as related patents are described below:
1. John Deere 6000 Series
In these tractors an electrical switch is provided, as part of an Electro-hydraulic system, for lifting and lowering the implement, in addition to position and draft controls. Manually putting the switch into the ON or OFF position, sends a signal to an electronic control unit, to lift or lower the implement. Being an Electro-hydraulic system, it necessarily requires electronic control unit and sensors.
2. Ford New Holland 3030, 3230, and 3630
In these tractor models manual control is provided to lift an implement to a fixed height and lower the same to the preset depth, in addition to the position and the draft controls. In this mechanism two push buttons are provided, one for lifting & another for lowering. When the lift button is pressed, the motion is transmitted to the spool of the control valve via a linkage arrangement, causing oil flow into the cylinder & subsequent rising of the hitched implement to its maximum height,
2

which is fixed. When the lowering button is pressed, the linkage arrangement moves in the opposite direction, allowing oil flow out of the cylinder & the implement is lowered.
The operator cannot adjust the height of the implement rise to any intermediate position below this maximum height, using the above control.
3. Improved Lifting and Lowering System (Patent No. IN 197898)
This patent claims a lifting and lowering system, wherein the lifting and lowering operation of implement is made automatic in relation to the vehicle's reverse operation or steering operation by means of electrical sensing. In this mechanism, the lifting and lowering of the implements is achieved through movement of position control lever itself after latching this lever into automatic mode position. Thus this control mechanism is not independent of position control-and to operate the position control, the operator needs to unlatch the position control lever from the automatic mode.
4. 'A push button lift control mechanism for Tractors having mechanically
operated hydraulic controls' (Patent Application No. 145/DEL/2Q05)
This patent describes a mechanism similar in function to that explained in point no. 2. (Ford New Holland tractor models 3030, 3230, 3630).
Here also the operator cannot adjust the lifting height of the implement to any intermediate position below the maximum height.
NEED OF THE INVENTION
In field operations, during turning of the tractor at the headland, the implement requires to be raised to clear the ground. The height to which it should be raised depends on implement size and the 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. Therefore, a need exists for a mechanism to lift and lower tractor implement to an adjustable height in addition to hydraulic position and draft controls, wherein the operator can pre-set the lifting height of the implement to any desired value, just enough to clear the ground.
OBJECTS OF THE INVENTION
A primary objective of the present invention is to propose a mechanical control mechanism in addition to tractor hydraulic position and draft control mechanisms, to lift the implement to a pre-set height adjustable by the operator and lower the same to its original position, independent of both position and draft controls.
Another objective of this invention is to propose a push button for lift and another push button to lower the implement.
A further objective of this invention is to propose a push button control to lift the implement to a height adjusted by the operator and bring the hydraulic system in neutral after the height is achieved.
A still further objective of this invention is to propose a push button to lower the implement to a preset depth corresponding to the setting of position and draft controls.
BRIEF DESCRIPTION OF THE DRAWINGS
For understanding various aspects of this invention, the mechanism will now be
explained with the aid of the following drawings ;
Figurel: shows existing hydraulic system with position and draft control
mechanism
Figure2: shows front view of proposed mechanism to lift and lower tractor
implement to an adjustable height, in addition to position and draft control
4

mechanism as shown in figure 1.
Figure3: shows top view of proposed mechanism to lift and lower tractor implement to an adjustable height in addition, to position and draft control mechanism as shown in figure 1.
DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENT
The present tractor hydraulic system comprises, a pump (1), supplying pressurizes oil to hydraulic control valve (2) having a spool (31), with a cylinder (3) & piston (4) connected to it. The operation of the spool (31) of the control valve (2) causes the flow of pressurized oil into the cylinder (3), to cause lifting of lift arm (7) & flow of oil out of the cylinder (3), to cause lowering. The piston (4) is connected to the Rocker arm (5) & Rockshaft (6) through a Connecting Rod (10), all of which are fitted inside the hydraulic lift Housing (18). Pair of Lift arms {7) % mounted on either end of the Rockshaft (6). Lift Rod, Lower Links & Top Link constitute various elements of what is described as a 3-point linkage (8), enabling the appropriate attachment of the implement (9) to the tractor. Finally the present tractor hydraulic system contains position controls (29) & draft controls (30), controlling implement lifting / lowering & response to soil force, corresponding to the movement of the position & draft control levers by the operator.
The present invention proposes a mechanism in addition to the present position & draft control mechanisms in hydraulic system of tractor or similar vehicle. The various elements of the propose mechanism & their working are described below:
The mechanism consists of operating control unit (26) in the form of button / switch mounted on Quadrant Frame (28) of the existing Position & Draft Control mechanism. When the Lifting Control (11) is operated by the operator, it causes rotation of Link external (14). When the operator releases his palm from the

Lifting Control (11), it remains in its operated condition by virtue of the Intermediate Crank (13) locking into the upper notch on the metallic insert of Lifting Control (11). Lifting Control (11), Lowering Control (12) & Crank Intermediate (13) are all pivoted on the shanks of the mounting fasteners (32) of operating control unit (26). The Rod Spring Assembly (15), whose one pin is connected at the bottom of the Link External (14). It is the Rod Cross Tube (17), which is transferring the movement (rotation) from the link external (14) to the hydraulic Lift Housing (18), to those elements inside the hydraulic lift housing & for that purpose it is pivoted at either end of the hydraulic lift housing & extends beyond on one side (Right Hand side). On this side Crank External Actuation (16) is attached to the Rod Cross Tube (17). Connecting the Crank External Actuation (16) to the Link External (14) is the Rod Spring Assembly (15), completing the input side of the external mechanism.
Inside the hydraulic lift housing (18), the Crank Internal (19) is mounted onto the Rod Cross Tube (17). At the other end of the Crank Internal (19), is connected one end of the Link Internal (20), which receives a back-ward pull. The other end of the Link Internal (20) is attached to the pin at the upper end of Blade Actuating (21). The backward pull to the Link Internal, causes the bottom portion of Blade Actuating (which is pivoted near its center) to press the spool of the control valve (2). This causes the hydraulic control valve (2) to supply pressurized oil to the cylinder (3). The consequent outward movement of the Piston (4) causes the movement of the connecting rod (10), rotation of the Rocker arm (5) & Rockshaft (6) & hence finally the pair of lift arms (7), thus lifting the attached implement (9).
This continues until the feedback linkage (23) stops this upward movement of the lift arms (7). For this feedback action to happen, the extended RH side portion of the rod cross tube (17), has another crank called Crank External Feedback (21) fixed to the Rod Cross Tube (17). At the free end of the Crank External Feedback (21) is fitted the pin of the Block Rotary (25), which as the name suggests forms a rotary joint with Crank External Feedback. The feedback is taken externally from the face of the Rockshaft (6), using a fastener called Pivot Rod Adjustable
6

Feedback (22). Finally what connects the Pivot Rod Adjustable Feedback (22) to the Crank External Feedback (21) is an element described as Rod Adjustable Feedback (23). The Rod Adjustable Feedback is hinged on the Pivot Rod Adjustable Feedback & its rod slides into the hole present in the Block Rotary (25) forming a sliding pair. This rod has external threads on which rotate a collar (35) & a lock nut (34). By using this locknut, the collar can be tightened to remain at a particular location on the threaded portion, maintaining a gap between the collar (35) & the Block Rotary (25).
This is how the feedback action actually occurs. When the lift arm (7) move upwards corresponding to the operation of lifting control (11), it is followed by rotation of the rockshaft (6) & hence the pivot rod adjustable feedback (22) attached to it. This rotation causes the collar of Rod Adjustable Feedback (23) to come closer towards the Block Rotary (25), finally moving the Block Rotary & through it rotating the Crank External Feedback (21) in the opposite direction to its initial movement. It is this opposite rotation that ultimately causes the spool of the hydraulic control valve (2) that was initially pressed inwards to come back to neutral condition. As the lifting control button is locked in place with intermediate crank. This reverse rotation is absorbed by the spring element of Rod Spring Assembly (15). Oil flow from the hydraulic control valve (2) to the Cylinder (3) stops & thus the pair of Lift Arms (7), which were rising, become steady with the Implement (9) in lifted condition at some "height". This "height" corresponds to the initial gap that was maintained by locking the collar of the Rod Adjustable Feedback (23) at a particular position. Increasing the gap or decreasing this gap by changing the position of locking of the collar (35), causes the angle of lift of implement to correspondingly decrease or increase. This adjustment is located such that it is easily accessible to the operator, who needs to change this lift height based on the size of the bunds in the area of use & based on then size of the implement (9).
When tne Lowering Control (12) is pressed down by the operator, it causes the Intermediate Crank (13) to move, thus releasing the Lifting Control (11) till it

comes to rest with the Intermediate Crank engaging with the other notch, due to spring action. This causes rotation of the Link external (14) in the opposite direction. The Rod Spring Assembly (15), connected at the bottom of the Link External (14) gets pushed towards the rear, rotating the Rod Cross Tube (17) in the anti-clockwise direction when viewed from the RH side of the hydraulic Lift Housing (18) through the Crank External Actuation (16). This rotation of the Rod Cross Tube causes the forward movement of the Link Internal (20), which receives a forward push. The forward push to the Link Internal, causes the bottom portion of Blade Actuating (21) to move further away from the spool (31) of the hydraulic control valve (2), causing it to work in the lowering mode. The Cylinder (3) gets connected to the reservoir (18) & the Lift Arms (7) will lower the implement (9) to the preset height.

We Claim :-
1. A mechanism to lift and lower implement to an adjustable height, in addition
to hydraulic position and draft controls, in a tractor or similar vehicles
comprising ;
- A lifting control (11) to lift the attached implement (9) to an adjustable height;
- A lowering control (12) to lower said implement to the pre-set height.
2. A mechanism to lift and lower implement to an adjustable height, in addition to
hydcaulic position and draft controls, as claimed in claim 1, wherein said lifting & lowering controls in turn actuates the spool (31) of the control valve (2) of said position and draft control mechanism by means of External Link (14), Rod Spring Assembly (15), Rod Cross Tube (17), Internal Link (20), Actuating Blade (21) and the like connected in-between said operating controls (11 and 12) and said spool of said control valve wherein ;
- when said lifting control is operated, it causes supply of pressurized oil from said control valve to a cylinder (3) causing outward movement of piston (4), thereby achieving rotation of a lift arm (7) and lifting of said implement to an adjustable height, which is attached by means of 3-point linkage mechanism (8) connected to said lift arm ;
- when said lowering control is operated, it releases said oil from said cylinder to the reservoir via said spool of said control valve causing inward movement of said piston, thereby achieving lowering of said lift arm & said implement to a pre-set height.
3. A mechanism to lift and lower implement to an adjustable height, in addition
to hydraulic position and draft controls, as claimed in claim 2, wherein ; an
adjustable means may be provided in between said rod cross tube and said
9

rockshaft or lift arm so as to cause the lifting movement of said lift arm / implement to an height, adjusted by the operator pased on field requirements.
4. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, as claimed in claim 3, wherein said adjustment means is in the form of turnbuckle (23), which when adjusted maintains the correlation between rotations of said rockshaft & said rod cross tube.
5. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, as claimed in claim 1, wherein said operating controls comprising :

- said lifting and lowering controls (11 & 12) are in the form of mechanical switch / button, positioned in an enclosure (26) by means of fasteners (32);
- said lifting control, is in turn, connected to said spool of said control valve by means of said External Link, Rod Spring Assembly, Rod Cross Tube, Internal Link, Actuating Blade and finally moving said spool;
- Intermediate Crank (13) locking with said lifting control to retain said lifting control to its moved position ;
- said lowering control, which moves said Intermediate Crank out of locking with said lifting control, allowing said lifting control to return to its initial position by means of return spring (33).
6. A mechanism to lift and lower implement to an adjustable height, in addition to
hydraulic position and draft controls, as claimed in claim 2, wherein rotation of

said rockshaft, causes the collar (35) of Rod Adjustable Feedback (23) to come closer towards and move the Block Rotary (25) & through it rotating the Crank External Feedback (21) in the opposite direction to its initial movement, which ultimately operates said spool of said control valve, that was initially pressed inwards to come back to neutral condition.
7. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, in a tractor or similar vehicles, wherein lifting & lowering controls (11 and 12) in turn actuates spool (31) of the control valve (2) of said position and draft control mechanism by means of External Link (14), Rod Spring Assembly (15), Rod Cross Tube (17), Internal Link (20), Actuating Blade (21) and the like connected in-between said operating controls and said spool of said control valve wherein ;
- when said lifting control is operated, it causes supply of pressurize oil from said control valve to a cylinder (3) causing outward movement of piston (4), thereby achieving rotation of a lift arm (7) and lifting of attached implement (9) to an adjustable height, which is attached by means of 3-point linkage mechanism (8) connected to said lift arm ;
- when said lowering control is operated, it releases the said oil from said cylinder to the reservoir via said spool of said control valve causing inward movement of said piston, thereby achieving lowering of said lift arm & said implement to a pre-set height;
- when said lifting control operates said cross rod tube, rotation of said rockshaft, causes the collar (35) of Rod Adjustable Feedback (23) to come closer towards and move the Block Rotary (25) & through it rotating the Crank External Feedback (21) in the opposite direction to its initial movement, which ultimately operates said spool of said control valve, that was initially pressed inwards to come back to neutral condition.

8. A mechanism to lift and lower implement to an adjustable height, in addition to hydraulic position and draft controls, as claimed in claim 7 comprising ;
said operating controls to lift & lower said implement to an adjustable height & pre-set position respectively ;

TO
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, MUMBAI
- said operating controls are in the form of mechanical switch / button, positioned in an enclosure (26) by means of fasteners (32);
- lifting control (11), in turn connected to said spool of said control valve by means of said External Link, Rod Spring Assembly, Rod Cross Tube, Internal Link, Actuating Blade and finally moving said spool;
- Intermediate Crank (13) locking with said lifting control to retain said lifting control to its moved position;
- lowering control (12), which moves said Intermediate Crank out of locking with said lifting control, allowing said lifting control to return to its initial position by means of return spring (33);
- adjustment means is in the form of turnbuckle (23), which upon adjustment maintains the correlation between rotations of said rockshaft & said rod cross tube.

A MECHANISM TO LIFT AND LOWER TRACTOR IMPLEMENT TO AN ADJUSTABLE HEIGHT IN ADDITION TO HYDRAULIC POSITION AND DRAFT CONTROLS

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