DESC:FIELD OF THE INVENTION
[001] The invention relates to hydraulic mechanisms, preferably hydraulic mechanisms of agriculture machineries and tandem pumps used therein.

BACKGROUND OF THE INVENTION
[002] Agricultural machineries such as tractors are provided with a hitch system at its rear end to attach earth working implements which are hydraulically controlled. A hydraulic pump supplies hydraulic fluid oil to the hitch system via a hydraulic flow line and engine or power drive of the tractor supplies power to the hydraulic pump.

[003] Further, tractors which have a hydraulic power steering system another hydraulic system may be required. Accordingly, two pumps would be required for providing oil to the hitch as well as the steering system. Adapting, two pumps consumes more space. Also the engine or power drive of the tractor in such a case would now be powering two hydraulic pumps which will consume more power of the engine, thereby affecting fuel consumption of the tractor.

[004] Another way of powering the hydraulic power steering system and the hitch system is by using a tandem pump. However the tandem pump delivers hydraulic fluid via two separate flow lines to both the steering and hitch system irrespective of whether any of the systems is being used or not. Therefore as soon as the tractor is switched on, the tandem pump provides oil to both the steering as well as the hitch system which continuously consumes engine power effecting the fuel consumption of the tractor.

[005] In view of the above, there is a need for a system and/or mechanism which overcomes the at least the above mentioned drawbacks.

SUMMARY OF THE INVENTION
[006] Accordingly the present invention provides a tandem pump for a vehicle in accordance with an embodiment of the present invention. The tandem pump includesa front section and a rear section for displacing hydraulic fluid received from an inlet port, a first shaft rotatably supported in the front section, a second shaft supported in the rear section and driven by the first shaft anda coupling section between the front section and the rear section wherein the coupling section includes a coupler configured for moving between a first position and a second position thereby enabling selective supply of hydraulic fluid to the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS
Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
[007] Fig. 1A shows a mechanically controlled tandem pump having a coupler for coupling a first shaft with a second shaft in accordance with an embodiment of the present invention.

[008] Fig. 1B shows a mechanically controlled tandem pump with decoupled first shaft and second shaft in accordance with an embodiment of the present invention.

[009] Fig. 2A shows a hydraulically controlled tandem pump having a coupler for coupling a first shaft with a second shaft in accordance with an embodiment of the present invention.
[0010] Fig. 2B shows a hydraulically controlled tandem pump with decoupled first shaft and second shaft in accordance with an embodiment of the present invention.

[0011] Fig. 3 shows agriculture machinery having a tandem pump in accordance with an embodiment of the present invention.

DESCRIPTION OF THE INVENTION
[0012] Accordingly, the present invention provides a selection mechanism for operating hydraulics of agriculture machineries such as tractors as per requirement.

[0013] In an embodiment, the selection mechanism allows an operator to cut off delivery of hydraulic fluid delivered to a device/implement which is not in operation, thereby providing hydraulic fluid only to the hydraulic device which is in operation.

[0014] In an embodiment, the present invention provides a tandem pump which cuts off supply of hydraulic fluid to one of the hydraulic lines which are not in operation.

[0015] Figure 1A, 1B and Figure 2A, 2B shows a tandem pump 100 in accordance with an embodiment of the invention. The tandem pump includes a front section 110, a rear section 120 and a coupling section 130.

[0016] The front section 110 is a hydraulic pump which displaces hydraulic fluid received from an inlet port. The front section 110 includes a first shaft 112 rotatably supported in the front section 110. The shaft is driven by an engine of an agricultural machinery such as a tractor. Upon rotation, the hydraulic fluid inside the front section 110 is discharged through an outlet port to a flow line for delivering hydraulic fluid to a device. In an example embodiment, the front section 110 delivers hydraulic fluid to a steering system 310 as shown in figure 3.

[0017] The rear section 120 is also a hydraulic pump which holds hydraulic fluid received from an inlet port. The rear section 120 includes a second shaft 122 for discharging the hydraulic fluid. In an embodiment of the invention, the second shaft 122 is driven/rotated by the first shaft 112 when the second shaft 122 is connected with the first shaft 112. Upon rotation, the hydraulic fluid inside the rear section is discharged through an outlet port to a flow line for delivering hydraulic fluid to device(s). In an example embodiment, the rear section 120 delivers hydraulic fluid to a hitch system 320, and/or auxiliary valve 330 and/or trailer brake valve as shown in figure 3.

[0018] The coupling section 130 is provided between the front section 110 and the rear section 120 of the tandem pump. The coupling section 130 comprises of a coupler 132 capable of moving between a first position and a second position. In the first position as shown in Figure 1A and 2A the coupler couples the first shaft 112 with the second shaft 122, wherein rotation of the first shaft 112 rotates the second shaft 122. In the second position as shown in Figure 1B and 2B the coupler moves the first shaft 112 away from the second shaft 122, thereby decoupling the second shaft 122. In this regard, the second shaft 122 only rotates when it is connected with the first shaft 112. Accordingly, the front section 110 continuously delivers hydraulic fluid to the steering system and the rear section 120 delivers fluid to the hitch system and/or auxiliary valve 330 and/or trailer brake valve only when the coupler is in first position i.e. when the first shaft 112 is connected to the second shaft 122. Advantageously, hydraulic fluid is delivered to the hitch system 320, and/or auxiliary valve 330 and/or trailer brake valve as per requirement and not continuously, especially since the hitch system and/or auxiliary valve would not be in operation during transport and stationery PTO operations. Furthermore, in context of trailer brake valve for trailer 350, the trailer brake valve is operated by a tractor brake 340 and the valve gets loaded even if trailer 350 is not attached to the tractor. However, the present invention allows the rear section 120 of the tandem pump to be declutched or disengaged in haulage avoiding loading of trailer brake valve, thereby saving unnecessary loading of trailer brake thus saving on fuel.

[0019] In an embodiment, the coupler can be mechanically controlled as shown in figure 1A and 1B.

[0020] In an embodiment, the coupler can be hydraulically controlled as shown in figure 2A and 2B.

[0021] In an embodiment, the coupler can be electrically controlled.

[0022] Figure 3 shows an agricultural machinery 300 comprising tandem pump 100 of the present invention. As shown the tandem pump 100 is connected to steering system 310, hitch system 320, auxiliary valve 330, and trailer brake valve of the tractor.

[0023] Advantageously, the present invention increases efficiency of the machinery by cutting off the flow line which is not in use, thereby consuming less engine power.

[0024] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the disclosure and the appended claims.
,CLAIMS:1. A tandem pump for a vehicle comprising:
a front section 110 and a rear section 120 for displacing hydraulic fluid received from an inlet port;
a first shaft 112 rotatably supported in the front section 110;
a second shaft 122 supported in the rear section 120 and driven by the first shaft 112; and
a coupling section between the front section and the rear section wherein the coupling section includes a coupler configured for moving between a first position and a second position thereby enabling selective supply of hydraulic fluid to the vehicle.

2. The pump as claimed in claim 1 wherein the coupler is in first position when the first shaft is connected to the second shaft.

3. The pump as claimed in claim 1 wherein the coupler is in second position when the first shaft and the second shaft are not connected.

4. The pump as claimed in claim 1 wherein the first shaft is driven by an engine or power drive of the vehicle.

5. The pump as claimed in claim 2 wherein the front section 110 continuously delivers hydraulic fluid to a steering system of the vehicle and the rear section 120 delivers fluid to a hitch system and/or auxiliary valve 330 and/or trailer brake valve of the vehicle when the coupler is in first position.

6. The pump as claimed in claim 1 wherein the hydraulic fluid inside the rear section is discharged through an outlet port to a flow line for delivering hydraulic fluid.

7. The pump as claimed in claim 6 wherein the coupler in second position cuts off the flow line when not is use.