FORM 2
THE PATENT ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
PROVISIONAL SPECIFICATION
(See section 10 and rule 13)


1. TITLE OF THE INVENTION
A SYSTEM FOR TRACTOR JACKING
2. APPLICANT
MAHINDRA & MAHINDRA LTD.
1, GATEWAY BUILDING, APOLLO BUNDER, MUMBAI - 400001.
AN INDIAN COMPANY.

The following specification describes the invention.


Field of the Invention
The present invention relates to a jacking system for off-road vehicle, in particular tractor to raise front and / or rear wheel/s off the ground or supporting surface.
Background of the Invention
Off-road vehicles such as tractors are extensively used in fields. In particular tractor is used for agricultural applications. In the field, to change wheels of the tractor it is essential to raise front and / or rear wheels. Commonly available jacks are required to be inserted beneath the tractor / off-road vehicle and one has to raise the same using external force, in most of the cases manual. Raising the wheels is a cumbersome process. It results in loss of valuable time in the fields. Further, operator has to make provision to mount / carry a jack on the tractor. In the field poses problems in handling. Some of the jacks are integrated with the three point linkage mechanism of the tractor. However, the three point linkage mechanism of the tractor is not used in some of the field applications such as puddling. If the mechanism is detached from the tractor, jacking of the tractor becomes impossible.
Attempts on development of jacking system for tractor are reported in prior art. They are as follows:
GB Patent 592175 discloses an improvement relating to jack devices of tractors. It comprises a beam having an abutment between its ends and on its upper face. The abutment is adapted to be engaged under the rear axle casing of the tractor has rear end adapted for connection to the lower end of one of the lift rods. The other end of the beam is pivotally attached to aground engaging member so that when the power unit is operated to raise the lift rod the beam is caused to pivot about its front end and thus to raise the rear axle of the vehicle.

US Patent 2744724 discloses tractor jack comprising two separator pieces that use the power lifted movements of the trailing hitch links for selectively elevating front or rear wheels of the tractor.
US Patent 2222116 discloses tractor jack, it comprises a jack frame arrangement that is fitted with hydraulic cylinder of the tractor that is used for lifting implements. The jack frame structure consists of three .members, one of which is capable of extension, a second member takes the form of a lever fulcrumed at an intermediate point along its length, and a third member provides support wherein all the members are pivoted with respect to each other.
G8 Patent 1275552 discloses improvements related to jacking members for tractor. The jacking member comprises a rigid, one piece, generally U shaped frame wherein the U comprises a pair of legs connected at one end by a transverse member, serving as a ground contacting portion in use of the jacking member.
US Patent 2250964 discloses tractor jack. It comprises plurality of stands, tie-rods interconnecting the stands, and means for joining at .least one of the stands to the hydraulic mechanism of the tractor.
US Patent 3730482 discloses a device for jacking the rear wheel assemblies of a tractor, in the form of an attachment to be operated by the conventional three point hitch assembly mounted on the tractor. The jack comprises interconnected uprights to raise the tractor from the ground surface with the upper end of the uprights supporting the rear axle assembly of the tractor.
US Patent 2348743 discloses self-confirming tractor jack. It comprises front and rear stands arranged at an angel to the vertical on the supporting surface beneath the tractor, a chain interconnecting the lower most portions of the said

stands, the other end of the chain detachably connected to operating links so as to shift the stand towards a vertical position to lift the tractor.
US Patent 2712431 discloses improved tractor jack mechanism comprising a stand, an extensible arm having one end pivotally connected to said stand, means on the other end of the said arm for selectively pivotally securing said arm to the hitch link in either its extended or retracted condition, for respectively selectively positioning said stand in engagement with the underside of the tractor.
The study of the related aforementioned prior art reveals shortcomings such as: Instability of the lifted tractor uneven distribution and transmission of the tractor load to the support of the jack resulting in tilting leading in some cases to the toppling of the support during operation In particular, in the case of GB patent 592175 the lack of provision to align and orient the support link with the lower link creates lateral thrust resulting in instability of the tractor.
Limitations in the three point linkage mechanism which is generally not used in certain seasons due to inappropriate soil conditions thereby requiring the demounting of the existing three point linkage with other accessories and attachments related to the jacking system in the tractor for use when necessary, requiring considerable effort and time; (nterference of the jacking system with the three point finkage mechanism and in many cases making it imperative to modify the lower links that may lead to the weakening of the existing system..
A jacking system integrated with tractor utilizing auxiliary power sources available on the tractor, in particular three point linkage system is reported in the prior art wherein available lower link which is a part of three point link mechanism has to be reoriented at the time of jacking the tractor. However, the three point linkage mechanism that is not used in all the seasons on the tractor. Further, in field operations like puddling, three point linkage is not used. Further, the

reorientation and fitment of the lower link is a tirne consuming process. This system has swiveling joints within the jacking mechanism. This results in dislocation of the support centerline with respect to the line of action of force of the centre of gravity of the tractor resulting in sideways forces making tractor instable when jacked.
Necessity has constantly been felt to develop a jacking system independent of the three point linkage mechanism of the tractor arid without interfering with the same yet using auxiliary power available at the rotating shaft and lift arm of the tractor during the jacking operation to raise / elevate front and/or rear wheel(s) of the tractor selectively off the ground / supporting surface(s)
Object of the Invention
The object of the invention is to provide a jacking System that is independent of the three point linkage mechanism for off-road vehicle such as tractor to raise front and/or rear wheel{s) selectively off the ground and / or supporting surface(s).
Another object of the invention is to provide an integrated jacking system that is detachably mounted on the tractor so that the jacking system can be easily removed.
Another object of the invention is to provide the said jacking system that can be operated by a single operator when required and without the need of special equipments.
Another object of the invention is to use available auxiliary power of the tractor.
Yet another object of the invention is to obviate modifications in the lower link of the tractor.

Yet another object of the invention is to provide a jacking system that does not interfere with the three point linkage mechanism and hitching system of the tractor.
Another object of the invention is to provide easy to handle jacking system for tractor.
Another object of the invention is to provide jacking system that facilitates raising single rear wheel at a time as well as both rear wheels at a time of the tractor.
Yet another object of the invention is to provide jacking system so as to obviate reorientation of the lower link of the three point mechanism with respect to support of the jacking system.
Another object of the invention is to provide a jacking system that is stable during the operation of jacking.
Thus, in accordance with the invention, the system comprises a rocker lever further comprising first end that is adapted for pivotal fitting with a link such as lift rod of the tractor, or is adapted for sliding over a lower link provided on the tractor, which is pivotally connected with a link such as lift rod of the tractor, second spherical pin end that is adapted to fit in the universal swivel joint, a pivot provision disposed in between the said two ends, pins to pivotally couple the said ends;
a ground support member comprising universally swiveling joint arrangement adapted to removably receive the second end of the said rocker lever, a housing adapted to fit the said swivel joint, a support surface for the housing that is in contact with ground.

Detailed Description of the Invention
Features and advantages of this invention will become apparent in the following detailed description and the preferred embodiments with reference to the accompanying drawings.
Figure 1 - Schematic of the jacking mechanism (Sheet 1) Figure 2 - Schematic of jacking (Sheet 2) Figure 3 - Schematic of the system rear view (Sheet 3) Figure 4 - Schematic of another embodiment (Sheet 4)
The schematic of the system is depicted in Figure 1. The system effectively uses auxiliary power of the tractor available at the rotatable shaft 5 that is operatively connected to the one of the ends of lift arm 3. The other end of the said lift arm is pivotally coupled at 10 with the one of the ends of a link such as lift rod 2. The other end 11 of the said link / lift rod 2 is pivotally connected to one of the ends 18 of the rocker lever 4. The rocker lever is provided with a coupling provision 7. A coupling provision 12 is adapted to be fitted to the tractor chassis 6 wherein the said provision 12 is disposed below the tractor chassis towards rear side of the tractor as shown in the figure such that the coupling provision 7 of the rocker lever 4 pivotally engages with the coupling provision 12. A pin (not shown) is used to engage the same. The other end 13 of the rocker lever 4 is connected to the ground support member 8 that comprises a spherical type, universally swiveling joint 9.
During jacking operation the said rotatable shaft 5 is rotated using auxiliary power resulting in rotation of the said lift arm 3 upwardly. This is depicted in Figure 2 wherein rear wheel 1 of the tractor is raised. This result in lifting the

said link / lift rod 2 and in turn the end 11 of the same. The rocker lever 4 as a result pivots about the said provision 12 with its end 13 pushing downwards so as to exert downward force at the said support joint 9 of the ground support member 8. By virtue of the characteristics of the universal swivel joint 9, the force transmitted to the support is the vertical force which is balanced with the vertically upwardly acting reaction from the ground. The effect of sidewise / resolved thrust component of the transmitted force is nullified resulting in achieving stability in the operation by avoiding possible tilting of the support.
The Figure 3 depicts rear view of the tractor with one of the rear wheels lifted with the said jacking system. The jacking system is seen mounted on the left side of the tractor. The provision 15 indicated in this figure for hitching the lift rod of the normal three point linkage does not interfere with the jacking mechanism.
The schematic of the system in another embodiment is depicted in Figure 4. The rotatable shaft 5 is operatively connected to the one of the ends of lift arm 3. The other end of the said lift arm is pivotally coupled at 10 with the one of the ends of the link / lift rod 2. Here, lower link 16 is available as a part of three point linkage of the tractor. The other end 11 of the link / lift rod is pivotally connected to lower link on its span. At the same time, the lower link is pivoted to the tractor chassis with the coupling 17. One of the ends 18 of the rocker lever 4 is made to slide on the upper surface of the lower link with the provision of a pin type arrangement covering the top surface width of the lower link 16. When there is no lower link 16 in its place, then the other end 11 of the link / lift rod 2 is pivotally connected to one of the ends 18 of the rocker lever 4 with joining means like a pin joint (as shown as link 2' in the Figure 4). The rocker lever 4 is provided with a coupling provision 7. A coupling provision 12 is adapted to be fitted to the tractor chassis 6 wherein the said provision is disposed below the tractor chassis towards rear-bottom side of the tractor as shown in the figure such that the coupling provision 7 of the rocker lever 4 pivotally engages with the coupling provision 12. A pin (not shown) is used to engage the same.

The other end of the rocker lever 4 is connected to the ground support member 8 that comprises a spherical type, universally swiveling joint 9.
During jacking operation, the said rotatable shaft 5 is rotated using auxiliary power resulting in rotation of the said lift arm 3 upwardly. This result in lifting the said link / lift rod 2 and in turn the end 11 of the same.
When there is lower link present as a part of three point linkage on the tractor, the lift arm end 11 being connected to the lower link turns the lower link upward about its pivot 17. This movement of the lower link causes the rocker lever end 18 to go upward with the lower link with the sliding action between the top surface of the lower link and the pin at rocker lever end 18. When there is no lower link available, the link / lift rod end 11 is directly connected pivotally with the end 18 of the rocker lever, thus forming the same system as explained above in the main embodiment. The rocker lever 4 as a result pivots around the said provision 12 with its end 13 pushing downwards so as to exert downward force at the said support joint 9 of the ground support member 8.
The jacking system of the present invention addresses most of the shortcomings of the prior art, such as provide a system capable of lifting a single rear wheel at a time as well as providing flexibility of raising both the wheels if two sets of jacking systems are used on two sides. Further, the present jacking system can be operated without interference with three point linkage or implement hitch mechanism. An additional advantage of the present system is that, when one of the rear wheels is selectively lifted, the other wheel that is on the ground adds to provide a stable support to the tractor making it easy to safely service the wheel that is jacked above the ground. Use of a spherical type universally swiveling joint between the rocker lever and the ground support element provides a larger contact area between

ground or support surface and the ground support element. Further, the construction of the jacking system is sUch that the operation of attachment or removal involves use of only two pins thereby making the operation simple and quick / time efficient that also can be handled by a single unaided operator.
Thus it is evident that the judicious combination of the rocker lever 4 adapted to be fitted with the link / lift rod, disposition of the said coupling provision 12 and the universal swjVel joint 9 of the ground support result in provision of a jacking system that obviates the use of lower link of the three point linkage yet effectively uses the auxiliary power providing a stable, simple, quick and easy to operate jacking system for tractor or similar applications.