FIELD OF INVENTION
This invention relates to a distributor of hydraulic lift assembly for agricultural tractor hitch control.
BACKGROUND OF INVENTION
Tractors are provided with three-point hitch linkage, and have hydraulic actuator for raising and lowering of the linkage which carries the implement. Raising & lowering operations take place in accordance with control direction from the operator. Distributor, which is a key part of the hydraulic lift of the tractor, enables this as per the need.
Distributor directs pressure oil from the pump to the lift cylinder to cause lifting of the implement, or directs pressure oil from lift cylinder to the tank to cause lowering of the implement.
Weights of implements which would be lifted by the hitch are also controlled by the distributor. For this, a pressure control arrangement, which enables it to function as a pressure-regulating device is carried within the distributor housing. This arrangement helps in controlling the weight of implements to be managed by the tractor.
The pressure control arrangement, housed within distributor body, consists of spring, ball and passage or openings linking pressure oil to the valve & tank. Oil being delivered to Lift Cylinder is exposed to the valve through an opening & other end of the valve contains passage which opens to the tank.
When the force due to operating pressure increases more than a pre-set value obtained from the spring, the ball gets lifted and excess oil pressure is relieved to the tank. Oil is diverted to the tank till the force due to excess pressure becomes less than the force of the holding spring. Thus operating pressure of the oil being delivered to lift cylinder is controlled within the pre-set value depending on force of the holding spring.
Over a period of time. Lift capacity requirements of tractors have increased due to emergence of heavier implements.
One of the ways to obtain high lift capacity is by increasing the setting of pressure control valve. Setting of higher value pressure results in increased force produced by the lift cylinder and hence capability of lift heavier implements.
As per prior art, pressure control arrangement is located in the distributor body as described above, along with other constructional elements. Owing to this the following inconveniences are faced:
- Machining requirements and manufacturing process steps are complex. (Requirement of large sized part handling)
- Testing of the Distributor is cumbersome. Linkage to other constructional elements within the distributor influences the performance of pressure control arrangement & need to be accounted for.
- Need to have variety of distributors (with possibility of parts mix up) to meet requirements of different Lift capacities.
- Change in the Distributor in case of requirement for any improvement in pressure control arrangement.
OBJECTS OF THE INVENTION
The primary object of the present invention is to provide an improved distributor of hydraulic lift assembly, which overcomes disadvantages associated with the prior art.
Another object of the present invention is to provide a Distributor of hydraulic lift assembly, having provision for adopting a detachable 8B modular pressure control arrangement.
Further object of the present invention is to provide an improved distributor of hydraulic lift assembly, which is not affected by changes in the pressure control arrangement.
Yet another object of the present invention is to provide a detachable and separate pressure control arrangement, which can be easily fitted or removed from the Distributor.
Further object of the present invention is to provide an improved distributor of hydraulic lift assembly wherein without affecting the distributor, any improvements can be applied to this valve, which can be set as per Lift capacity needs.
STATEMENT OF INVENTION
According to this invention, there is provided a distributor of hydraulic lift assembly for agricultural tractor hitch control comprising of removal portion carrying the pressure control elements, which is modified to provide thread for adopting detachable and modular relief valve.
BRIEF DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS: -
Further objects and advantages of this invention will be more apparent with the accompanying drawings and wherein:
Fig 1 shows: Drawing of the Distributor with sectional view showing the pressure control arrangement.
Fig 2 shows : Views of the Distributor body depicting the new details inclusive of provision of adopting modular relief valve.
Fig 3 shows : Pressure control valve parts housed in a separate and modular construction which can be fitted in the provision made in the distributor.
Fig 4 shows : Sectional view of modified Distributor with separate Modular type relief valve fitted on it
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWIGNS:
Reference may be made to fig .1, wherein a known distributor 1 carries pressure control valve arrangement 2. The pressure control valve arrangement consists of Ball 3 which when seated closes the gallery 9 with the help of spring retainer 4 and Compression Spring 5. Initial Force of the compression spring 5 imposed on Ball 3 through Spring retainer 4 can be adjusted by tightening or loosening the Adopter 6. Above the ball 3 are openings 7 8B 8 for the oil to escape to the tank.
When force of the pressure oil increases more than that of the spring force on the Ball, the ball lifts and makes way for the pressure oil to escape through openings 7 & 8. When pressure in the gallery 9 is less than the preset spring installation force, Ball 3 sits back on the seat and path for oil to escape to the tank is closed. Thus, the pressure control is obtained.
According to this invention, there is provided a distributor of hydraulic lift assembly for agricultural tractor hitch control. Reference may be made to -fig. 2, which shows the distributor body wherein portion carrying the pressure control elements has been removed 8B modified to provide -thread 10 for adopting detachable & modular relief valve.
Removal of the parts & machining required to accommodate the parts within distributor housing simplifies the machining 8B other associated steps for processing of the Distributor housing.
Since Relief valve has been made detachable - its performance checks. can be carried out separately on the standard Relief valve test benches. Testing of the Distributor as per invention does not include the relief valve related performance 8B durability tests. Hence, it gets simplified.
Figure 3 shows the pressure control elements arranged in a separate 8B detachable modular construction, which can be easily fitted on or removed from the Distributor. This arrangement can be separately tested and incorporated with modifications related to pressure control without disturbing the Distributor.
Fig. 4 shows the modified Distributor along with detachable & modular relief valve.
ADVANTAGEOUS FEATURES
- Simplified construction obtained by deletion of pressure control arrangement parts & modification of the body.
- Provision of means to adopt a detachable external pressure control arrangement.
- A detachable & modular type separate pressure control arrangement for the simplified Distributor.
It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-

WE CLAIM;
1. A distributor of hydraulic lift assembly for agricultural tractor hitch control comprising of removal portion carrying the pressure control elements, which is modified to provide thread for adopting detachable and modular relief valve.
2. A distributor as claimed in claim 1, wherein said removal of the parts and machining to accommodate the parts within distributor housing simplifies the machining and other associated steps for processing of the distributor housing.
3. A distributor of hydraulic lift assembly for agricultural tractor hitch control substantially as herein described with reference to the accompanying drawings.