DESC:TECHNICAL FIELD
[001] The embodiments herein generally relates to a power take off drive system in vehicles and more particularly but not exclusively to a ground speed power take off drive system in agricultural vehicles.

BACKGROUND
[002] Conventionally, agricultural tractors are fitted with power take off (PTO) systems which allow the transfer of torque from the prime mover to an attached implement. Examples of implements that utilize PTO systems include balers, fertilizer spreaders, seed drills and hedge cutters etc. The power take off (PTO) includes a rotary shaft that drives the shaft of the implement or equipment for working of the implement. PTO can be used for powering either stationary or moving implement that move along with the tractor.
[003] Some implements demand a constant ratio between the groundspeed and the PTO speed. Some tractors provide a groundspeed PTO mode wherein the propulsion drive to the wheels is directly coupled by meshed gears to the PTO stub. The ratio between groundspeed and PTO speed in such a mode is fixed by the gears installed during manufacture and the size of tyre fitted.
[004] When a groundspeed PTO mode is provided, problems may occur when switching between groundspeed and engine speed PTO drive. For example, where the groundspeed PTO is connected to the front or rear axle driveline, the PTO cannot be switched under load and issues such as interlocking between tractor and implement during turns cannot be avoided.
[005] Generally for operating the PTO based on the ground speed the PTO shaft is driven through a pinion or input shaft of the gearbox which includes speed reduction means and hence the gearbox is more complex and occupies more volume.
[006] Therefore, there exists a need for providing a ground speed power take off drive system for the tractor that eliminates the aforementioned drawbacks.

OBJECTS
[007] The principal object of an embodiment herein is to provide a driving system for a PTO of an agricultural vehicle based on ground speed of the agricultural vehicle.
[008] Another object of an embodiment herein is to provide a method for driving a PTO of an agricultural vehicle based on ground speed of the agricultural vehicle.
[009] Another object of an embodiment herein is to provide a drive system which is capable of maintaining PTO speed at a desired ratio with respect to ground speed.
[0010] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF DRAWINGS
[0011] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0012] FIG. 1 depicts a perspective view of a PTO drive system, according to an embodiment as disclosed herein;
[0013] FIG. 2a depicts the flow of engine speed from a second input shaft to a PTO shaft, according to an embodiment as disclosed herein;
[0014] Fig. 2b depicts the flow of engine speed from a first input shaft to a PTO shaft, according to an embodiment as disclosed herein; and
[0015] FIG. 3 depicts the flow diagram of a method 200 for driving a power take off in vehicles, according to an embodiment as disclosed herein.

DETAILED DESCRIPTION
[0016] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0017] The embodiments herein achieve a system and method for driving a PTO of a tractor based on ground speed of the tractor. Referring now to the drawings, and more particularly to FIGS. 1 through 2, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0018] In one embodiment, the drive system 100 includes a first input shaft 102, a first input member 104, a second input member 106, a first output member 108, a first output shaft 110, a coupler 112 and a PTO shaft 114.
[0019] FIG. 1 depicts a perspective view of a PTO drive system 100, according to an embodiment as disclosed herein. In an embodiment, the first input shaft 102 is driven independently by the engine through a clutch mechanism. The clutch mechanism used is a friction clutch mechanism. The first input shaft 102 rotates at a speed same as that of the engine.
[0020] In an embodiment, the first input shaft 102 is coupled to a first input member 104. In an embodiment, the first input member 104 is a bevel pinion connected to the first input shaft 102. However, it is also within the scope of the invention to provide any type of gear without otherwise deterring the intended function of the transmission as can be deduced from this description and corresponding drawings. In an embodiment, the first input member is selected from a group consisting of bevel pinion, straight bevel gear, spiral bevel gear, Zerol bevel gears and Hypoid bevel gears.
[0021] Further, the first input member 104 is connected perpendicularly to the second input member 106. In an embodiment, the second input member 106 is a crown gear that engages with the first input member 104.The second input member 106 rotates when the engine rotates the first input member 104 through first input shaft 102.
[0022] In an embodiment, the second input member 106 is connected to the first output member 108. The first output member 108 is a bevel pinion. However, it is also within the scope of the invention to provide any type of gear without otherwise deterring the intended function of the transmission as can be deduced from this description and corresponding drawings. In an embodiment, the first input member is selected from a group consisting of bevel pinion, straight bevel gear, spiral bevel gear, Zerol bevel gears and Hypoid bevel gears.
[0023] In an embodiment, the crown gear is paired with the first output member 108 for gear reduction. In an embodiment, the first output member 108 is connected perpendicularly to the first output shaft 110. Further, the first output shaft 110 is coupled to the PTO shaft 114 through the coupler 112. In an embodiment, the first output shaft 110 includes an axis of rotation coaxial to an axis of rotation of the first input shaft 102. Further, the first output shaft 110 includes a rotational speed which is a function of a rotation speed of the first input member 104 and the second input member 106.
[0024] Referring to FIG. 2a and 2b, the coupler 112 includes a shift mechanism to operably connect the first output shaft 110 to the PTO shaft 114. In an embodiment, the coupler 112 is operated in first position to establish a driving connection between the first input shaft and the power take-off shaft as shown is FIG. 2b. In an embodiment, the coupler 112 is operated in second position to establish a driving connection between a second input shaft and the power take-off shaft as shown in FIG. 2a.
[0025] In an embodiment, the second input shaft 116 is driven by the speed of the engine. The speed at which the shaft 116 rotates is the RPM of the engine. The speed transferred from the engine to the second input shaft 116 is coupled to the PTO shaft 114 through driving gears 118.
[0026] A method 200 for driving a power take off in vehicles includes steps of coupling a first input shaft 102 to an engine shaft (step 201). The first input shaft 102 is driven independently through a clutch mechanism associated with the engine. Further, the method includes coupling a first input member 104 to the first input shaft 102 (step 202). The first output shaft 110 having a rotation speed which is a function of a rotation speed of the first input member 104 and the second input member 106. Further, connecting a second input member 106 perpendicularly to the first input member 104 (step 203). Furthermore, connecting a first output member 108 perpendicularly to the second input member 106 (step 204). Further, coupling a first output shaft 110 to the first output member 108 (step 205). Also, coupling a PTO shaft 114 to the first output shaft 110 through a coupler 112 (step 206). The coupler includes a shift mechanism to operably connect the first output shaft to the PTO shaft.
[0027] In an embodiment, the drive system 100 is provided without consuming any additional space in the existing transmission. Further, the transmission use less oil compared any benchmark transmission. Thus, reducing churning loss and increasing the efficiency. Also, the drive system 100 is provided without affecting the ground clearance, i.e. more ground clearance compared to any other GD PTO transmission/tractor.
[0028] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

REFERRAL NUMERALS
First input shaft 102
First input member 104
Second input member 106
First output member 108
First output shaft 110
Coupler 112
PTO shaft 114
Second input shaft 116
Driving gear 118

,CLAIMS:CLAIMS
We claim,
1. A power take off drive system 100 for vehicles, said drive system 100 comprising:
a first input shaft 102 coupled to an engine shaft;
a first input member 104 coupled to the first input shaft 102;
a second input member 106 perpendicularly connected to the first input member 104;
a first output member 108 connected perpendicularly to the second input member 106;
a first output shaft 110 coupled to the first output member 108;
a PTO shaft 114 coupled to the first output shaft 110 through a coupler 112;
wherein,
the first input shaft 102 is driven independently through a clutch mechanism associated with the engine;
the first output shaft 110 includes an axis of rotation coaxial to an axis of rotation of the first input shaft 102;
the first output shaft 110 having a rotation speed which is a function of a rotation speed of the first input member 104 and the second input member 106;
the coupler 112 includes a shift mechanism to operably connect the first output shaft 110 to the PTO shaft 114.

2. The drive system 100 as claimed in claim 1, wherein the first input member 104 is selected from a group consisting of bevel pinion, straight bevel gear, spiral bevel gear, Zerol bevel gears and Hypoid bevel gears.

3. The drive system 100 as claimed in claim 1, wherein and the first output member 108 is selected from a group consisting of bevel pinion, straight bevel gear, spiral bevel gear, Zerol bevel gears and Hypoid bevel gears.

4. The drive system 100 as claimed in claim 1, wherein the second input member 106 is a crown gear that engages with the first input member 104 and the first output member 108.

5. The drive system 100 as claimed in claim 1, wherein the coupler 112 is configured to shift to a plurality of positions.

6. The coupler 112 as claimed in claim 5, wherein the coupler 112 is operated in first position to establish a driving connection between the first input shaft 102 and the power take-off shaft 114.

7. The coupler 112 as claimed in claim 5, wherein the coupler 112 is operated in second position to establish a driving connection between a second input shaft 116 and the power take-off shaft 114.

8. The drive system 100 as claimed in claim 1, wherein the clutch mechanism is a friction clutch mechanism.

9. The drive system 100 as claimed in claim 1, wherein the second input member 106 is paired with the first output member 108 for gear reduction.

10. A method 200 for driving a power take off in vehicles, said method 200 comprising steps of:
coupling a first input shaft 102 to an engine shaft;
coupling a first input member 104 to the first input shaft 102;
connecting a second input member 106 perpendicularly to the first input member 104;
connecting a first output member 108 perpendicularly to the second input member 106;
coupling a first output shaft 110 to the first output member 108;
coupling a PTO shaft 114 to the first output shaft 110 through a coupler 112;
wherein,
the first input shaft 102 is driven independently through a clutch mechanism associated with the engine;
the first output shaft 110 includes an axis of rotation coaxial to an axis of rotation of the first input shaft 102;
the first output shaft 110 having a rotation speed which is a function of a rotation speed of the first input member 104 and the second input member 106;
the coupler 112 includes a shift mechanism to operably connect the first output shaft 110 to the PTO shaft 114.