Hydraulic lifting mechanisms control a multitude of apparatus mounted on three-poir linkages. At the heart of the mechanism is a Flow Control Valve [FCV] that regulates an controls the functioning of the hydraulic lifting mechanism. At the heart of the FCV is a Plunge that determines the sensitivity and capability of the FCV and in turn the Hydraulic Liftin mechanism itself. The present invention discloses a unique conjoint Plunger that materiall improves the sensitivity of the FCV and gives additional performance capabilities to the liftin mechanism.
DESCRIPTION OF PRIOR ART
FLOW CONTROL VALVES are known to the Art. it is also known to the Art that the sensitivit of the actuator mechanism inside the FCV directly affects the efficiency, efficacy, an capability of the Hydraulic mechanism that the FCV controls. The FCV known to the Art has a its actuator a plunger that consists of two disjointed parts, placed together to make workable whole. Both ends of the plunger are spring loaded to respond to input signals unde differing directions. The springs give the plunger the semblance of a single whole, wherea the plunger is made up of two distinct pieces. The plunger is aligned by way of 0 Rings in chamber containing hydraulic oil that the plunger regulates. The design of the end of on piece of the plunger is such that there is a tubular structure of a diameter greater than th body of the plunger [Structure]. This Structure at one position of the plunger overlaps witl the entry holes inside the oil chamber, thereby closing the entry holes and stopping the flov of hydraulic oil. During the discharge phase of the FCV, the Structure is retracted by th* displacement of the control lever, allowing the hydraulic oil to freely flow from the entry hole inside the oil chamber and thereby facilitating the discharge phase in conjunction with thi hydraulic flow system. The movement of the plunger is orchestrated by a physical inpu displacement that determines the position of the plunger. There is delay on account of thi two-piece configuration of the plunger as it withdraws from the chamber, that is furthe compounded by the inherent inertia on account of the spring-loaded mechanism tha regulates the position of the plunger inside the oil filled chamber. Further the Structun retraction in the plunger of the Art leads to delays in hydraulic response as the mechanisn goes from one extreme position to the other. This is of material consequence in determinin, the sensitivity of the device leading to consequential sub optimal efficiency of the hydrauli lifting mechanism. Continued vise of the FCV known to the Art also leads to generation of hea on account of the oil sealing mechanism, and increase in device temperature, leading t< intermittent stoppages. The present invention minimizes the inherent inefficiencies of th< plunger known to the Art.

SUMMARY OF THE PRESENT INVENTION
The present invention disclosed herein cures the inherent inefficiencies present in the FCV of the Art, i.e., substantially reduces response cycle time for movement from one extreme output position to the other; substantially increases the intermittent step positions of the FCV output positions, leading to substantial increase of specific intermittent positions of lifting arm of the three point linkage which can be accurately controlled to stop at any of the increased intermittent positions; lower inertia of the system; longer uninterrupted usage of the FCV and consequentially the hydraulic mechanism; reduced load factor on the system leading to enhanced life and usage; reduced engine RPM leading to reduced fuel consumption; consequential reduction in harmful engine emissions.
The conjoint plunger [Plunger] is designed to work without the top spring-loaded end, as compared to the plunger of the Art. The top section of the Plunger is screwed on to the bottom section making this a conjoint whole. The top section is such that it is loaded by way of an internal spring so precisely designed as to impart the right tension to the conjoint system. When an input displacement if effectuated, the conjoint plunger moves in a manner such that the tapered structure at the lower end of the top section moves and sits exactly against the circular end of the internal chamber walls, thereby blocking the hydraulic oil from flowing out of the circular hole against which the tapered end sits. The lower segment of the conjoint plunger gently enters inside the hollow top segment thereby compressing the internal spring mechanism and avoiding an impact between the tapered end and the circular end of the internal chamber. This prevents a hard collision that would otherwise drastically reduce the life of the system. The vector pressure created by the internal spring ensures that the oil sealing is sound and no oil escapes during the delivery phase of operation; further the response time of output to an input displacement is inherently instantaneous both on account of the conjoint nature of the Plunger as well as the tapered segment disengaging with the circular end of the internal chamber wall, as opposed to the Art; the sensitivity of positioning of the Plunger is such that the output lever (which determines the position of the lifting arm of the three point linkage) can accurately be placed at intervals of 2 mm compared to intervals of 6 mm in case of Plunger of the Art; While the Plunger of the Art resulted in. the FCV output having 117 positions at intervals of 6mm, the Plunger disclosed in the present invention has the capability and sensitivity of having up to 350 steps at intervals of 2mm each. The angular taper in the lower segment of the Plunger is designed in such a manner that output movement of the FCV device from one extreme to another extreme position (i.e., extreme positions of the lifting arm of the three-point linkage) requires substantially lower displacement of input to the actuator Plunger. This substantially lowers the lifting and lowering time of the hydraulic mechanism.
The Plunger is designed such that the oil in the chamber is sealed by way of metal-to-metal

DESCRIPTION OF THE PREFERRED EMBODIMENT
Once the Vector push or pull is experienced by the apparatus being controlled, this is translated as an input directional displacement signal to the bottom end of the Plunger. Unlike the prior Art, the Plunger moves as a single whole being a conjoint union. There is no delay in the process as in the case of prior art in which the displacement gets passed on by the lower section of the plunger to the upper section of the plunger by way of momentum. Equally so in the case of reverse movement of the plunger, the whole plunger moves down without any delay, as it does not depend on the spring action that propels the downward movement in case of the plunger of the Art. The system sensitivity is enhanced multifold.
The number of discreet positions that the single Plunger disclosed in this invention can take is also substantially higher than the two-piece plunger of the Art. Based on actual performance indicators it is seen that the plunger of the Art is capable of discreet steps that translates into output steps of 6mm each; this translates into 300 to 350 discreet positions of 2 mm each at the output that the Plunger can translate and hold on to, compared to only 117 discreet positions that the plunger of the Art is capable of. This results in a higher sensitivity of the FCV and the hydraulic device which controls the three-point linkage. The lifter link in the disclosed invention can hold stable position at up to three times the discreet levels that the lifter controlled by the plunger of the Art.
The angular taper at point C (FIGURE 1) is such that the ratio of input displacement movement to output movement of the lifter link is substantially more efficient compared to the plunger of the Art. This also ensures reduced time for lifting and lowering from one extreme point of the lifter Arm to the other. This results in substantially improved efficiency in performance of the entire hydraulic based system that the FCV and in turn the Plunger controls.
The devices based on the plunger of the Art have severe restrictions as regards the type of operation that they can cater to since the accuracy and sensitivity of the FCV based on the plunger of the Art is deficient. A device that may be capable of levelling operation may not be efficient at seed drilling, cultivator, Rotavator and MB Plough. This necessitates that the end user maintains different devices for different operations, rather than have one device for all types of operations. The disclosed Plunger ensures a substantially higher sensitivity and accuracy of the FCV that is actuates, thereby eliminating the need for different devices for different operations. The speed of response of the system ensures levelling operation of any type of soil; the discreet positions available for setting the lifter link ensures accurate seed drilling operation; the height control of the attached implement results in efficient performance under different conditions; the rapid response of movement of the lifter arm and higher sensitivity ensures that no area of land is left without being cultivated, especially during turning of the device, as compared to the large portions of uncultivated land in case of devices actuated by the plunger of the Art; The inherent efficiency and enhanced sensitivity of the disclosed invention also eliminates the need to have very high engine speeds of the tractor, as the speed of movement of the lifter link compensates for the reduction in speed of movement of the tractor. This results in reduced wear and tear, as also reduced fuel consumption. On a macro scale this reduces greenhouse emissions from the tractor engine.

WE CLAIM

1. A conjoint Plunger that materially enhances the sensitivity of a Flow Control Valve which controls the hydraulic system of a three-point linkage attached to a tractor. In its preferred embodiment, the number of discreet steps that the FCV is capable of transmitting to the lifting arm increases from the existing 117 steps of 6mm each to up to 350 steps of 2 mm each.
2. A plunger of Claim 1 that results in the FCV precisely controlling the attached implement leading to enhanced efficiency in Levelling operations.
3. A Plunger of Claim 1 that gives the FCV the capacity to finely control Seed Drill operation.
4. A plunger of Claim 1 that results in enhanced capacity of the tractor to do controlled cultivation.
5. A plunger of Claim 1 that results in enhanced capacity of the tractor to do controlled Rotavator/ MB Plough.
6. A Plunger of Claim 1 that gives the FCV the capability to control the three-point linkage such that no area is left without cultivation or without engagement of the implement, even during turning of the machine in the field.
7. A Plunger of Claim 1 that eliminates the need to use separate tractors for Levelling, Seed Drill and Cultivation applications.
8. A Plunger of Claim 1 that results of reduced engine speed of the tractor without loss of efficiency, reduced load on engine leading to increased life of the engine and the pump.
9. A Plunger of Claim 1 that results in reduced wear and tear of the implement and increased life span.