FIELD OF INVENTION
The present invention relates to an electrically controlled hydraulic pump drive. BACKGROUND OF INVENTION
In agricultural tractor, for hydraulic system the main source of power is hydraulic gear pump (prime mover). The purpose of pump is to push the hydraulic fluid and to create flow and pressure. In agricultural tractor it forces oil from the oil reservoir to hydraulic ram cylinder through filter and distributor. In India, tractors are having relatively low engine hp and therefore when tractor runs on road during haulage operation, hydraulic pump driving gear is still engaged with cam gear with continuous flow of oil from reservoir to hydraulic ram cylinder, which is not required. It also creates unnecessary suction pressure which creates problem in suction line when transport lock is in locked position. Due to continuous creation of suction pressure, hydraulic pump or suction pressure line may get damaged. To avoid this type of unfavorable condition, there should be engagement/disengagement of pump driving gear with cam gear as per the requirement. The engagement/disengagement of hydraulic pump driving gear can be achieved /controlled electrically. Reference may be made to fig. 1 indicating hydraulic pump mounting along with filter and suction line. Reference may be made to fig. 1.
OBJECTS OF THE INVENTION
The primary object of the present invention is to provide an electrically controlled hydraulic pump drive which overcomes disadvantages associated with the prior art.

Another object of the invention is to provide an eleclrieally controlled hydraulic pump drive which is efficient.
Still another object of the invention is to provide an electrically controlled hydraulic pump drive which is simple in construction.
STATEMENT OF INVENTION
According to this invention, there is provided an electrically controlled hydraulic pump drive comprising of built in solenoid with hydraulic pump for movement of shaft mounted with hydraulic pump gear facilitating engagement/disengagement of the pump driving gear with the ram shaft gear.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS: -
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accom.panying drawings and wherein:
Figure 1 shows : conventional tractor with hydraulic pump and filter mounting. Figure 2 shows : schematic view of electrically controlled hydraulic pump drive in disengaged condition (OFF position).
Figure 3 shows ; schematic view of electrically controlled hydraulic pump drive in engaged condition {ON position).
DETAILED DESCRIPTION OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:
The present invention discloses an electrically controlled hydraulic pump drive comprising of built-in solenoid with hydraulic pump for movement of

shaft on which hydraulic pump gear is mounted facilitating engagement/disengagement of the pump driving gear with the cam shaft gear.
In the Present Invention, for engaging and disengaging of hydraulic pump driving gear with cam gear, an operating system is provided comprising of a solenoid and a floating shaft. With the help of solenoid, the shaft/gear can be moved from its original disengaged position to engaged position. For operating solenoid, an electrical switch is provided.
Among all the components of hydraulic system of agricultural tractor, hydraulic pump is the most important component, which causes flow of oil from oil reservoir to ram cylinder through filter and distributor to operate the three point linkages. This controls the lifting and dropping of the implements. Hydraulic system of a tractor is live hydraulic system which consumes engine power at load and also in no load condition. In another way, hydraulic pump runs continuously when the engine is running. Hence, power loss due to hydraulic pump running takes place continuously even when the hydraulic operation is not required.
For engagement/disengagement of hydraulic pump driving gear with cam shaft gear, a solenoid is built-in with the hydraulic pump which moves the shaft to and fro. When the current flows through the solenoid, i.e. when switch is in ON position, the solenoid pushes the pinion towards cam gear and as a result the pump driving gear gets engaged as shown in fig. 3. When switch is in OFF position, the pinion comes back to its neutral position and hydraulic pump driving gear gets disengaged as shown in fig. 2. Hence by keeping switch in ON/OFF position, the hydraulic pump driving gear can be engaged /disengaged as per the requirement.

ADVANTAGEOUS FEATURES OF ELECTRICALLY CONTROLLED HYDRAULIC PUMP DRIVE
1) Prevention of power loss when hydraulic operations are not required by disengaging the hydraulic pump driving gear.
2) Prevention of excessive wear and tear of hydraulic pump driving gear, hydraulic pump's parts as well as cam shaft gear.
3) Enhancement in the life of pump, hydraulic pressure lines, valves etc. due to limited use of hydraulic pump as per the requirement.
4) Prevention of damage of pump and suction line when transport lock is in locked position.
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. An electrically controlled hydraulic pump drive comprising of built in solenoid with hydraulic pump for movement of shaft mounted with hydraulic pump gear facilitating engagement/disengagement of the pump driving gear with the cam shaft gear.
2. An electrically controlled hydraulic pump drive as claimed in claim 1, wherein said engagement/disengagement of the hydraulic pump driving gear with cam gear is carried out by means of an operating system.
3. An electrically controlled hydraulic pump drive as claimed in claim 2, wherein said operating system comprising of a solenoid and a floating shaft.
4. An electrically controlled hydraulic pump drive as claimed in any of the preceding claims, wherein said shaft/gear can be moved from its disengaged position to engaged position by means of the solenoid, for operation of which an electrical switch is provided.
5. An electrically controlled hydraulic pump drive as claimed in any of the preceding claims, wherein when the switch is in ON position, the driving gear gets engaged as shown in fig. 3 and when the switch is in OFF position, the driving gear gets disengaged as shown in fig. 2.
6. An electrically controlled hydraulic pump drive as claimed in any of the preceding claims, wherein the hydraulic pump drive is associated with several advantageous features such as herein described.
7. An electrically controlled hydraulic pump drive substantially as herein described with reference to the accompanying drawings.