FORM 2
THE PATENTS ACT 1970
(39 of 1970)
AND
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"POWER TAKE-OFF DRIVE SYSTEM FOR OFF ROAD VEHICLES"
2. APPLICANT;
(a) NAME: MAHINDRA & MAHINDRA LTD.
(b)NATIONALITY: Indian Company incorporated under the Companies Act, 1956
(c) ADDRESS: Gateway Building, Apollo Bender, Mumbai - 400001, Maharashtra, India.
3. PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be formed.

FIELD OF THE INVENTION:
The present invention relates to a transmission system incorporating a power take-off drive system for use with off road vehicles such as tractors and alike, and particularly, concerned with a power take-off drive arrangement for establishing both clockwise and anticlockwise rotation at outer end of a power take off drive shaft that is exposed outside of transmission housing of the vehicles.
BACKGROUND OF THE INVENTION:
Power take-off drive system for the tractors is used to operate attached implements. This power take-off (herein after referred as PTO) drive system operate at a single speed or dual speed based on the speed range of implements. Based on certain usage conditions, the PTO gets stuck and results in no power. During that time, operator has to manually remove the obstacles in the implement for running smoothly. In that case reverse PTO arrangement is provided to reduce the operator difficulties. Generally reverse PTO comprises essential components such as set of spur gears with idler arrangement for changing the direction of rotation of the PTO shaft. This type of construction ensures unique advantage of easy manufacturing and assembly. But this type of arrangement have disadvantage such as power flow cannot be obtained inline (same axis), more weight, more space requirement and thus increasing packaging issues, and increased cost due to high number of components. Further replacing single speed PTO with reversible PTO arrangement leads to complete design change and thus it cannot be provided as add on features to customer.
Hence, to eliminate all the disadvantages associated with spur gear arrangement in reverse power take-off drive system, bevel gear arrangement is made to provide low cost and low weight reverse power take-off arrangement. In this arrangement, the same spur gear pair of single PTO is used along with the bevel gear with idler bevel gear for achieving reverse power flow. Since same spur gear pair is used, reduction ratio of the bevel gear with idler gear will be less when compared to spur gear arrangement for reverse power flow. Complete reduction is required to be obtained with the single spur gear pair with idler gear in case of spur gear arrangement as it poses difficulty in designing spur gear for inline shafts. Further this bevel gear arrangement can be provided

as a separate gear box as an add-on feature thus reducing the cost of converting single speed PTO to reverse dual speed PTO.
In US4327603 titled "Compact Transmission for Tracked Vehicle", a transmission system for a tracked vehicle is disclosed. The transmission system in said invention includes a reversing mechanism which further includes a pair of reversing clutches which are positioned for the rotation concentric with main shaft. The transmission system also includes gear means comprising a pinion and a bevel gear drive.
In US4895052 titled "Steer Driven Reduction Drive System", a reduction drive system is disclosed. The said system comprises a pair of differential reduction drives, a pair of worm gears, a steering control shaft, bevel gears, and a steering motor. The worm gears are rotationally interconnected so that steering torque applied to the reduction drive is respectively equal and opposite.
However, aforementioned prior arts use bevel-pinion gear arrangement in differential mechanism. The additional rotation of power take-off shaft in reverse direction is not achieved in both the prior arts.
SUMMARY OF THE INVENTION:
The main objective of the present invention is to provide a power take-off drive arrangement for use with off road vehicles such as tractors and alike and establish both clockwise rotation and anticlockwise rotation at backward end of a power take-off shaft which transfer power available at flywheel of the engine to the implements attached thereto. The power take-off drive arrangement disclosed herein below add benefits in cost effectiveness, weight reduction of the entire transmission system and compactness in packing the entire transmission system.
Accordingly, the present invention discloses power take-off drive system consisting of a pinion shaft to transfer power from flywheel to a power take-off shaft which is extended backward and projected outward of a gear box housing to drive implements attached thereto, a coupling device for drivingly coupling a coupling shaft and the pinion shaft to convert direction of rotation of the coupling shaft into either clockwise rotation or anticlockwise rotation at the power take-off shaft as per the requirement, a first bevel

pinion gear, a second bevel idler gear and a third bevel gear arranged in such a way to maintain clockwise rotation of the coupling shaft at the power take-off shaft by engaging the coupling device with a cog-wheel attached to the first bevel pinion gear, a cog ring for converting clockwise rotation of the coupling shaft into anticlockwise rotation at the power take-off shaft by engaging the coupling device therewith, and a gear for transferring power from the pinion shaft to the power take-off shaft.
BRIEF DESCRIPTION OF DRAWINGS:
FIG. 1 is a longitudinal section of a transmission layout used with off-road vehicles incorporating a Power Take-off drive system in accordance with the present invention.
FIG. 2 is an enlarged cut sectional view of the power take-off drive system of FIG. 1.
FIG. 3 is an enlarged cut sectional view of power flow arrangement of the power take-off drive system of FIG. 2 through anticlockwise rotation of a power take-off shaft.
FIG. 4 is an enlarged cut sectional view of power flow arrangement of the power take-off drive system of FIG. 2 through clockwise rotation of the power take-off shaft.
FIG. 5 is enlarged longitudinal section of power take-off drive arrangement of FIG. 3 & FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION:
The following description of the preferred embodiment or embodiments shall be deemed as an example of the principles of the present invention and not intended to limit the invention to any specific embodiment shown and described. In the description below, like reference numerals are used to describe the same, similar or corresponding parts in the several views of FIG 1-5.
The present invention provides a transmission system incorporating a power take-off drive system, for use with off road vehicles such as tractors and alike, for establishing both clockwise and anticlockwise rotation at outer end of a power take off drive shaft that is exposed outside of transmission housing of the vehicles.

The present invention is adapted as a separate module which can be added to the existing transmission layout by providing necessary flexible support, in the case, without much modification as per the requirement of the applications where reverse rotation of the power take-off shaft is mandatory. Thereby, this present invention gives an option to satisfy the operator by way of providing flexible transmission layout to operate the same vehicle for different applications.
The inventive aspect in said power take off drive, of the current invention, for use with off road vehicles, lies in a plurality of bevel gears arranged in order to either maintain clockwise rotation of a coupling shaft at the power take-off shaft by engaging the coupling device with a cog-wheel or convert clockwise rotation of the said coupling shaft into anti-clockwise rotation at the power take-off shaft by engaging said coupling device to a cog ring fitted therein.
Accordingly, in an embodiment, the present invention describes a power take-off drive(15) for use with off road vehicles, having provision for, both, clockwise and anticlockwise rotation at the back end of a power take-off shaft(27) housed therein. The power take-off drive comprises a pinion shaft(20), which is enabled to transfer power from flywheel of the off road vehicle to the power take-off shaft, extending backward and projected outward of a gear box housing, to drive implements attached thereto; a coupling device(23), which is enabled to drivingly couple a coupling shaft(19) and the pinion shaft(20) to convert direction of rotation of the coupling shaft into clockwise or anticlockwise rotation at the power take-off shaft(27) as required; a plurality of bevel gears arranged in order to either maintain clockwise rotation of the coupling shaft(19) at the power take-off shaft(27) by engaging the coupling device with a cog-wheel(39) or convert clockwise rotation of the said coupling shaft into anti-clockwise rotation at the power take-off shaft(27) by engaging said coupling device to a cog ring(36) fitted therein; and a gear enabled to transfer power from said pinion shaft to the power take-off shaft. Referring to FIG. 1, the transmission system layout(10) used for off road vehicles such as tractors and alike comprises a clutch housing(11) and a gear box(12). The clutch housing(11) encloses a flywheel(13) and a dual clutch system(14) which are axially and drivingly disposed so as to transfer the power available in the flywheel(13) to wheel of the vehicle and the power take-off drive system(l 5). The gear box(12) encloses speed and

range gear system (not shown), differential system (not shown) and the power take-off drive system(3 5). There is provided substantially elongated shaft(16) coupling forward end(17) thereof with the clutch system(14) via spline engagement means for transferring the power from the flywheel(13) to the power take-off drive system(15). A hollow shaft(18) is provided therein for operably engaging with the clutch system(14) for transferring power from the flywheel(13) to the speed and range gear system. In the transmission system, incorporating the dual clutch system, engaging and disengaging of the power take-off drive system with the engine power is performed with the help of conventional clutch pedal that is operably coupled with the dual clutch system. It is to be understood from the aforesaid description that although the present invention is designed and developed to operate with dual clutch system, any person skilled in the art may adapt the present invention for a transmission system incorporating a single clutch system without deviating from the scope of the present invention disclosed herein below.
Referring to FIG. 1 and FIG. 2, the power take-off drive system (15) receives power from the shaft(16) via the coupling shaft(19) which is coupled to the shaft(16) coaxially. The power take-off drive system(15) comprises the pinion shaft(20) having forward end(21) thereof is provided with spline on outer circumference and back ward end(22) is adapted to be rotatably supported with a first case(30), the coupling device(23) for drivingly coupling the coupling shaft(19) and the pinion shaft(20) to transfer the power from the coupling shaft(19) to the pinion shaft(20), a first bevel pinion gear(24), a second bevel idler gear(25) and a third bevel gear(26) wherein these first bevel pinion gear(24), second bevel idler gear(25) and third bevel gear(26) are operably arranged and engaged among themselves in such a way to transfer the rotary power from the coupling shaft(19) to the power take-off shaft(27) through a gear(28) and to convert the clock wise rotation of the coupling shaft(19) into anticlockwise rotation of the power take-off shaft(27).
Referring to FIG. 2 to FIG. 5, the backward end(22) of the pinion shaft(20) is adapted to receive a first bearing device(29) for rotatably supporting with the first case(30). Immediate forward portion of the pinion shaft(20) from the first bearing device(29) is provided with teeth(31) on outer circumference thereof for drivingly engaging with the gear(28). Immediately to the forward portion of the pinion shaft(20) from the teeth(31) is adapted to receive a second bearing device(32) for rotatably supporting with the first

case(30). Immediately to the forward portion of the pinion shaft(20) from the second bearing device(32), there is provided splines(33) around the outer circumference thereof for positively engaging with splines provided at inner diameter(34) of the third bevel gear(26). Spline provided at the forward end(21) of the pinion shaft(20) is adapted to receive splines provided at inner diameter(35) of the cog-ring(36). Outer diameter(37) of the cog ring(36) is also provided with splines. Immediate backward portion of the pinion shaft(20) form the cog ring(36) is machined to freely and rotatably receive inner diameter(38) of the first bevel pinion gear(24). The cog-wheel(39) is made integral part of said first bevel pinion gear(24) as shown in the figures and outer diameter (40) of a cog-wheel(39) is relatively made smaller than the outer diameter of the first bevel pinion gear(24) and made equal to the outer diameter(37) of the cog ring(36) to engage both the cog wheel and the cog ring with the help of the coupling device(23).
Further, the coupling device(23) is a hollow cylindrical member having its forward end(41) is formed with a first inner diameter(42) and backward end(43) is formed with a second diameter(44) which is relatively made smaller than the first diameter(42) to engage with forward end(45) of the coupling shaft(19) directly, wherein the first diameter is engaged with cog ring, which it turn engaged with the forward end(45) of the coupling shaft(19). Both the first inner diameter(42) and the second inner diameter(44) is provided with splines adapted to engage with splines provide at forward end(45) of the coupling shaft(19) and splines provided on the outer diameter of the cog ring(36) & cog-wheel(39), respectively. Adjacent to backward end(43) of the coupling device(23), there is provided a pair of extensions(46) from outer surface radially outward to operably receive a fork(47) to shift the position of the coupling device(23) from one position to another position. A first snap ring(48) is disposed at the spline section provided at forward end(45) of the coupling shaft(19) to restrict backward movement of the coupling device(23) from sliding away from the cog ring(36). The fork(47) is further operably coupled with an operating lever (not shown in figure) positioned at the vicinity of the operator to change direction of rotation of the power take of shaft(27) as per the requirement.
Further, the second bevel idler gear(25) consists of an extended portion(49) radially extending outward from outer contour along the central axis thereof. The extended

portion(49) define an outer diameter(50) adapted to receive a third bearing device(51) which is press fitted against a second larger outer diameter(52) of the extended portion(49). This assembly of the second bevel idler gear(25) and the third bearing device(51) is rotatably supported on an inwardly projected portion(53) of the housing(12). The portion(53) is projected from vertical wall(54) of the housing(12) forwardly at an inclined plane towards downward to rotatably support the second bevel idler gear(25) to continuously engage with the first bevel pinion gear(24) and the third bevel gear(26).
A bore(55) is provided at free end(56) of the projected portion(53) to rotatably hold the second bevel idler gear(25) and a second snap ring(57) is inserted at the outward end of the bore(55) to restrict outward axial movement of the second bevel idler gear(25).
The power take-off shaft(27) having its forward end adapted to receive a fourth bearing device(58) and rotatably supported on a vertical portion(59) of the housing(12). Adjacent to the fourth bearing device(58) is splines(60) on outer circumference of the power take-off shaft(27) to engage with splines provided at inner diameter of the gear(28) so as to receive the power from the pinion shaft(20) to transfer the power to implements (not shown) attached to backward end(61) of the power take-off shaft(27). The backward end(61) is provided with splines on outer circumference thereof to engage with attaching end of implements. A collar(62) is given immediate to the splines backwardly to restrict axial movement of the power take-off shaft(27) forward. Immediate to the collar(62), back ward of the power take-off shaft(27) is adapted to receive a fifth bearing device(63) for rotatably supporting the power take-off shaft(27) with the first case(30). A second case(64) is inserted from the backward end(61) of the power take-off shaft(27) and mounted on the first case(30) for the easy assembly and serviceability of the power take-off shaft output shaft arrangement with the help of mounting means such as bolt and alike. An inward projection(65) is projected from inner surface of the second case(64) and abuts with the fifth bearing device(63) to ensure rigid support to the power take-off shaft{27). A sealing device(66) is disposed in a hollow space(67) defined between the fifth bearing device(63), the second case(64) and the inward projection(65) to restrict entry of water or other foreign particles inside the housing(12). The first case(30) is mounted on to the vertical wall(54) of the housing(I2) via mounting means such as bolt or alike at upper end(68) and lower end(69) of the housing(12).

Working of the present invention is described herein below with reference to FIG. 2 to FIG. 5. Referring to FIG. 3, splines provided at the first diameter(42) of the forward end(41) and the second diameter(44) of the backward end(43) is permanently engaged with corresponding splines provided at outer diameter(37) of the cog ring(36) and corresponding splines provided at the backward end(45) of the coupling shaft(19), respectively. The cog ring(36) in turn is engaged with the splines provided at the forward end(21) of the pinion shaft(20) with the corresponding splines thereof. This position of the coupling device ensures the direction of rotation of the pinion shaft(20) as same as the coupling shaft(19), where the third bevel gear(26) rotates in the same direction at same speed as it is engaged with the pinion shaft(20) through splines. However, as the first bevel pinion gear(24) is freely rotating on the pinion shaft(20), clock wise rotation of the coupling shaft(19) is converted into anticlockwise rotation at the backward end(61) of the power take-off shaft(27).
Referring to FIG. 4, splines provided at the first diameter(42) of the forward end(41) and the second diameter(44) of the backward end(43) is permanently engaged with corresponding splines provided at outer diameter(40) of the cog-wheel(39) and corresponding splines provided at the backward end(45) of the coupling shaft(19), respectively. As the cog wheel(39) is integrated part of the first bevel pinion gear(24), the first bevel pinion gear (24) rotate in a direction as same as the coupling shaft (19), wherein, the third bevel gear(26), permanently engaged with the first bevel pinion gear(24) and the second bevel idler gear(25) rotates the pinion shaft(20) in anticlockwise rotation. The pinion shaft(20) then rotate the power take of shaft(27) in clockwise rotation.
The arrangement of bevel gears in the above disclosed instant invention is thus cost effective and with a less reduction ratio when compared with spur gear arrangement for reverse power flow. Further, the bevel gear arrangement disclosed in the present invention may also be provided as a separate gear box as an additional feature, reducing the cost of converting single speed power take-off to reverse dual speed power take-off.

We claim,

1. A power take-off drive(15) for use with off road vehicles, having provision for, both, clockwise and anti-clockwise rotation at the back end of a power take-off shaft(27) housed therein, comprising:
■ a pinion shaft(20), enabled to transfer power from flywheel of said off road vehicle to said power take-off shaft(27), extending backward and projected outward of a gear box housing, to drive implements attached thereto;
■ a coupling device(23), enabled to drivingly couple a coupling shaft(19) and the said pinion shaft(20) to convert direction of rotation of said coupling shaft into clockwise or anti-clockwise rotation at said power take-off shaft(27) as required;
■ a plurality of bevel gears arranged in order to either maintain clockwise rotation of said coupling shaft(19) at the said power take-off shaft(27) by engaging said coupling device(23) with a cog-wheel(39) or convert clockwise rotation of the said coupling shaft into anti-clockwise rotation at the said power take-off shaft(27) by engaging said coupling device to a cog ring(36) fitted therein;
and
■ a gear(28) enabled to transfer power from said pinion shaft to said power
take-off shaft.
2. The power take-off drive for use with off road vehicles as claimed in claim 1, wherein said plurality of bevel gears further comprise a first bevel pinion gear(24), a second bevel idler gear(25) and a third bevel gear(26).
3. The power take-off drive for use with off road vehicles as claimed in claim 2, wherein said first bevel pinion gear(24), second bevel idler gear(25) and third bevel gear(26) being operably arranged and engaged among themselves in a way to transfer rotary power from said coupling shaft(19) to said power take-off shaft(27) through said gear(28) and to convert clockwise rotation of said coupling shaft(19) into clockwise rotation of said power take-off shaft(27).

4. The power take-off drive for use with off road vehicles as claimed in claim 1 and 2, wherein said cog wheel(39) being made integral part of said first bevel pinion gear{24) for maintaining clockwise rotation.
5. The power take-off drive for use with off road vehicles as claimed in claim 3, wherein outer diameter(40) of said cog-wheel(39) being relatively made smaller than the outer diameter of said first bevel pinion gear(24) and being made equal to the outer diameter(37) of said cog ring(36) to engage both cog wheel and cog ring with the help of said coupling device(23).
6. The power take-off drive for use with off road vehicles as claimed in claim 2, wherein said second bevel idler gear(25) comprising an extended portion(49) defining an outer diameter(50) adapted to receive a third bearing device(51) being press fitted against a second larger outer diameter(52).
7. The power take-off drive for use with off road vehicles as claimed in claim 6, wherein an assembly of said second bevel idler gear(25) and third bearing device(51) being rotatably supported on an inwardly projected portion(53) of a housing(12).
8. The power take-off drive for use with off road vehicles as claimed in claim 7, wherein said inwardly projected portion(53) being projected from a vertical wall(54) of said housing(12) forwardly at an inclined plane towards downward to rotatably support said second bevel idler gear(25) to continuously engage with said first bevel pinion gear(24) and third bevel gear(26).
9. The power take-off drive for use with off road vehicles as claimed in claim 5, wherein a bore(55) being provided at a free end(56) of said projected portion(53) to rotatably hold said second bevel idler gear; a second snap ring(57) being inserted at an outward end of said bore(55) to restrict outward axial movement of said second bevel idler gear(25).

10. The power take-off drive for use with off road vehicles as claimed in claim 1 and 2, wherein said pinion shaft(20) having forward portion from a second bearing device(32) being provided splines(33) around the outer circumference thereof positively engaging with splines provided at inner diameter(34) of said third bevel gear(26).
11. The power take-off drive for use with off road vehicles as claimed in claim 1, wherein a spline provided at a forward end(21) of said pinion shaft(20) being adapted to receive splines provided at an inner diameter(35) of said cog ring(36).
12. The power take-off drive for use with off road vehicles as claimed in claim 1, wherein outer diameter(37) of said cog ring(36) being additionally provided with
splines.
13. The power take-off drive for use with off road vehicles as claimed in claims 1 and 2, wherein immediate backward portion of said pinion shaft(20) from said cog ring(36) being machined to freely and rotatably receive inner diameter(38) of said first bevel pinion gear(24).
14. The power take-off drive for use with off road vehicles as claimed in claim 1, wherein the said coupling device(23) being a hollow cylindrical member, having a forward end(41) formed with a first inner diameter(42) and backward end(43) formed with a second inner diameter(44) with splines, provided at both first and second diameter, adapted to engage with splines provided at forward end(45) of the coupling shaft(19) and splines provided on the outer diameter of the cog ring(36) & cog-wheel(39), respectively, said second inner diameter(44) being relatively smaller than said first inner diameter(42) to engage with said coupling shaft(19).
15. The power take-off drive for use with off road vehicles as claimed in claim 14, wherein a pair of extensions(46) being provided, adjacent to backward end(43) of said coupling device(23), from outer surface radially outward, to operably receive a fork(47) to shift the position of said coupling device(23) from one position to

another position, said fork(47) being further operably coupled with an operating lever positioned at the vicinity of the operator to change direction of rotation of said power take of shaft(27) as required.
16. The power take-off drive for use with off road vehicles as claimed in claims 1 and 14, wherein a first snap ring(48) being disposed at spline section provided at forward end(45) of said coupling shaft(19) to restrict backward movement of said coupling device(23) from sliding away from said cog ring(36).
17. The power take-off drive for use with off road vehicles as claimed in claims 1, 2, 11, wherein said cog ring(36) in turn engaged with the splines provided at said forward end(21) of said pinion shaft(20) with the corresponding splines thereof, ensuring the direction of rotation of said pinion shaft(20) same as said coupling shaft(19), wherein, said third bevel idler gear(26) rotates in the same direction at same speed being engaged with said pinion shaft(20) through splines.
18. The power take-off drive for use with off road vehicles as claimed in claims 1 and 2, wherein clock wise rotation of said coupling shaft(19) being converted into anticlockwise rotation at backward end(61) of said power take-off shaft(27) while said first bevel pinion gear(24) being freely rotating on said pinion shaft(20).
19. The power take-off drive for use with off road vehicles as claimed in claim 1, wherein bevel gear arrangement further provided as a separate gear box reducing cost of converting single speed power take-off to reverse dual speed power take-off.