FORM 2
THE PATENTS ACT 1970 (as amended)
[39 OF 1970]
&
The Patents Rules, 2003
COMPLETE SPECIFICATION [See Section 10 and Rule 13]
TITLE A SYSTEM FOR CHANGING DRIVE MODES OF A VEHICLE
NAME AND ADDRESS OF THE APPLICANT
TATA MOTORS LIMITED
an Indian company having its registered office at
Bombay house, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400 001,
Maharashtra, India
INVENTORS
(1) Anderson Allwyn Fernandes;
(2) S Venkata Bhaskar Sathi; and
(3) Aravind R
Nationality: INDIAN
of TATA MOTORS LIMITED
Bombay house, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400 001,
Maharashtra, INDIA
Preamble to the description
The following specification particularly describes the invention and the manner in
which it is to be performed.

TECHNICAL FIELD
The present disclosure generally relates to the field of transmission. More particularly, the present disclosure relates to a system for changing drive modes of a vehicle.
BACKGROUND OF DISCLOSURE
Driving conditions, drivers’ needs and/or aspirations pose varying demanding requirements for vehicle development. The road terrain situations like hilly, city, highways, flat road, etc. demands varying outputs from the engine of the vehicle. For example, for moving the vehicle uphill more power is required. Similarly, in heavy traffic, the vehicle has to crawl in low speeds. So it is always a challenging task to meet such different demands in a vehicle.
It is not always sufficient enough to power only one of the two axles of a vehicle, particularly during slippery terrains, on hilly and mountainous tracks where demand for torque at all four wheels is a basic need. To cater this niche of customers, most of the today’s vehicles are provided with 4x4 drive feature, wherein all four wheels of the vehicle can be selectively powered whenever required during the driving. Further, vehicles are provided with provision for shifting between 4x2 drive to 4x4 drive. Most common way of shifting between 4x2 drive to 4x4 drive is by using “Automatic 4x4 System”. The Automatic 4x4 System is also used for shifting between different drive modes such as 2-wheel drive high (2H), 4-wheel drive high (4H), Neutral (N) and 4-wheel drive low (4L). The Automatic 4x4 System involves an ECU (Electronic Controller Unit) and a number of electronic/ electrical components such as electronically compatible transfer-case, extra wiring harness, axle with auto hub-locks, switches to enable and disable this mode etc. Though this system is simple to operate, it is expensive and is not affordable by all segments of the customers due to the significant cost increase. Further, the conventionally known “Automatic 4x4 System” for changing drive modes of the vehicle involves electronic circuitry, electronic\ electrical elements and face several compatibility issues and is not reliable.
2

Few prior art documents disclose mechanical system for changing drive mode of vehicle, For example, one of the prior art document discloses a vehicle with a transfer gear and another prior art document discloses a four-wheel vehicle drive system that utilizes an arrangement for changeover of the drive modes of a vehicle. However, the arrangements disclosed in the prior art documents are complex, involves more number of parts, are expensive and packing thereof in the vehicle is difficult. Further, the arrangement for changing drive mode of the vehicle disclosed in most of the prior art documents fails to achieve a smoother changeover between the driving modes. Still further, the arrangement for changing drive mode of the vehicle fail to achieve positive gear shift engagement. Furthermore, the arrangement for changing drive mode produces rattling noise during changeover from one drive mode to another. In another prior art push pull control cables is used for changeover of the drive modes of a vehicle, however, with use of push-pull control cable for changeover of the drive modes of a vehicle the driver feels a grinding force pushing the shifter away and the changeover of the driving modes between 2H, 4H, N and 4L of the transfer case are not smoother and creates rattling noises.
Accordingly, there is need of a system for changing drive modes of a vehicle that mechanically operates to change drive mode of vehicle from one drive mode to another, without utilizing complex, expensive and delicate and unreliable electrical/ electronic elements. Further, there is a need for a system for changing drive modes of a vehicle that provide smooth changeover while shifting from one drive mode to another. Also, there is need of a system for changing drive modes of a vehicle that achieve positive gear shift engagement and reduce rattling noise during changeover from one drive mode to another. Also, there is need of a system for changing drive modes of a vehicle that is simple in construction, involves lesser number of parts, is in-expensive and packing thereof in the vehicle is simple and convenient. Also, there is need for a system for changing drive modes that enhances driving pleasure.
OBJECTS OF THE DISCLOSURE
3

An object of the resent disclosure is to provide a system that obviates drawbacks of the conventional systems for changing drive modes of a vehicle.
One object of the present disclosure is to provide a system for changing drive modes of a vehicle.
Another object of the present disclosure is to provide a system for changing drive modes of a vehicle that mechanically operates to change drive mode of vehicle from one drive mode to another, without utilizing complex, expensive and delicate and unreliable electrical/ electronic elements.
Yet another object of the present disclosure is to provide a system for changing drive modes of a vehicle that provide smooth changeover while shifting from one drive mode to another.
Further object of the present disclosure is to provide a system for changing drive modes of a vehicle that is simple in construction, involves lesser number of parts, is in-expensive and packing thereof in the vehicle is simple and convenient.
Furthermore, an object of the present disclosure is to provide a system for changing drive modes of a vehicle that reduces rattling noise during changeover from one drive mode to another.
SUMMARY OF THE DISCLOSURE
The shortcomings of the prior art are overcome and additional advantages are provided through the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
4

In an embodiment of the present disclosure a system (90) for changing drive modes of a vehicle is disclosed. The system (90) includes a guide bracket (02’), a lever (19), a pivot link (03), an adjustable link rod (11) and a shift shaft lever (06). The guide bracket (02’) is mounted over a floor (40) of the vehicle, wherein the guide bracket (02’) has a slot “S” configured thereon. The lever (19) is partially received and moves within the slot “S”. The pivot link (03) is pivotably supported underneath the guide bracket (02’). The pivot link (03) is connected to the lever (19) and swivels as the lever (19) moves within the slot “S”. The adjustable link rod (11) is securely connected to the pivot link (03) and moves as the pivot link swivels. The shift shaft lever (06) is securely mounted over and moves with the adjustable link rod (11) as actuation forces are transferred from the lever (19) to the shift shaft lever (06) via the pivot link (03) and the adjustable link rod (11) to cause actuation of the transfer case assembly disposed underneath the floor (40) for changing drive modes of the vehicle.
In accordance with an embodiment of the present disclosure, the system (90) further includes a mounting bracket (09) disposed underneath the guide bracket (02’) and that pivotably support the pivot link (03).
Further, the system (90) includes a dampening pad disposed between the mounting bracket (09) and the floor (40) for dampening the vibrations and rattling noises.
Typically, the pivot link (03) has a bush (05) configured thereon to receive a pin supported by the mounting bracket to facilitate pivotable movement of the pivot link (03) with respect to said mounting bracket (09).
In accordance with an embodiment, the bush (05) is a stepped bush.
Generally, the adjustable link rod (11) is provided with provision for adjusting length thereof to accommodate the inevitable variations during assembly.
Typically, the adjustable link rod (11) is configured of threaded elements.
5

Alternatively, the adjustable link rod (11) is hydraulic piston cylinder arrangement.
Typically, the shift shaft lever (06) has a pin (06’) configured thereon that engages with gears in the gearbox transfer case assembly for actuation thereof for changing drive modes.
In accordance with an embodiment, the lever (19) is connected to the pivot link (03) using bolt 15 and lock pin 16 arrangement.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
FIG. 1 illustrates a schematic representation of a system for changing drive modes of a vehicle in accordance with one embodiment of the present disclosure assembled in the vehicle;
FIG. 2 illustrates an assembled view of the system for changing drive modes of Figure 1;
FIG. 3 illustrates an exploded view of the system for changing drive modes of Figure 1;
FIG. 4 illustrates a schematic representation of the system for changing drive modes of Figure 1 in 2 wheel drive high speed (2H) mode;
FIG. 5 illustrates a schematic representation of the system for changing drive modes of Figure 1 in 4wheel drive and high speed (4H) mode;
6

FIG. 6 illustrates a schematic representation of the system for changing drive modes of Figure 1 in neutral mode; and
FIG. 7 illustrates a schematic representation of the system for changing drive modes of Figure 1 in 4 wheel drive low speed (4L) mode.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the system illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
The present disclosure provides a system for changing drive modes of a vehicle that mechanically operates to change drive mode of vehicle from one drive mode to another,
7

without utilizing complex, expensive and delicate and unreliable electrical/ electronic elements. The system for changing drive modes is actuated for actuating mechanical linkages. The mechanical linkages in turn facilitate shifting between various drive modes such as 2-wheel drive high speed (2H) mode, 4-wheel drive high speed (4H) mode, Neutral (N) mode and 4-wheel drive low speed (4L) mode, for example, for changing the drive mode of the vehicle from 4x2 drive to 4x4 drive and vice-versa.
This system for changing drive modes offers a substantial cost advantage compared to that of automatic system by eliminating electronic systems viz. ECU, Wiring harness etc. The system for changing drive modes offers enhanced reliability, reduced maintenance compared to that of “automatic system” by eliminating electronic systems viz. ECU, Wiring harness etc.
In the system for changing drive modes of the present disclosure, also referred to as Mechanical Shift Linkage (MSL) system for changing drive modes, a linkage assembly that includes a set of linkages is used to shift the gears to change drive modes between different modes such as between 4x4 and 4x2 vehicle drive modes. With use of the mechanical linkages for actuating the 4x4 drive mode in a four wheel vehicle numerous advantages are achieved. For example, with such configuration of mechanical linkages for changing the drive modes the positive gear shift engagement and smooth changeover while shifting from one drive mode to another is achieved. Further, with such configuration of mechanical linkages for changing the drive modes rattling noise during changeover from one drive mode to another is reduced.
FIG. 1, FIG. 2 and FIG. 3 illustrate different views of a system for changing drive modes of a vehicle, also referred to as Mechanical Shift Linkage (MSL) system for a multi axle 4x4 automobile. Particularly, FIG. 1 illustrates a schematic representation of the system assembled in the vehicle. Figure 2 illustrates an assembled view of the system. FIG. 3 illustrates an exploded view of the system.
8

The linkage assembly includes a linkage mechanism connected to a gear shift lever and transforming a driver gear’s shift movements therefrom into a rotational movement of a component that connects the linkages to drive gears in the gearbox transfer case assembly. In the illustrated embodiment, the system for changing drive modes is assembled to a vehicle 100 having transfer case assembly 30, a cabin and a floor 40, a center console 50, a main gear shift lever 60 and a driver seat 70. The mechanical shift linkages (MSL) system 90 are placed next to the main gear shift lever 60 between the console 50 and the driver seat 70 and is mounted on floor 40 and transfer case 30. With such configuration the mechanical shift linkages (MSL) system 90 is conveniently accessible to the driver.
As illustrated in Figure 1, a shift shaft lever 06 with a slot on one side is connected to transfer case assembly 30. Referring to Figure 3, the shift shaft lever 06 with pin 06’ is connected to pivot link 03 using an adjustable link rod 11. As will be clear to one skilled in the art, the shift shaft lever 06 and pivot link 03 may be alternatively replaced by any component or combination of components apt to make the required operational linkage gear mechanisms. The adjustable link rod 11 has the provisions 12 and 13 to adjust its length to accommodate the inevitable variations during the assembly of transfer case 30 underneath the cabin floor 40. Typically, the adjustable link rod (11) is configured of threaded elements. Alternatively, the adjustable link rod (11) is hydraulic piston cylinder arrangement. The present invention is not limited to any particular configuration of the adjustable link rod (11) to adjust its length to accommodate the inevitable variations during the assembly of transfer case 30 underneath the cabin floor 40.
The pivot link 03 with connection as described above is pivotably connected to mounting bracket 09 through rivet pin 08, bush 05 and step bush 05’ (refer FIG. 1 and 2). In turn, in respect of this invention the mounting bracket 09 is mounted on the cab floor 40 of vehicle 100 using bolt 17. This invention also uses a dampening pad 10 of special material to dampen the vibrations and rattling noises between the mounting bracket 09 and floor 40. With such configuration, the rattling noise during changeover from one drive mode to another is reduced.
9

The pivot link 03 is pivoted through rivets is connected to gear shift lever 19 using bolt 15 and lock pin 16 of assembly 14 (refer FIG. 1 and 3). As will be clear to one skilled in the art, the gear shift lever 19 and pivot link 03 may be alternatively connected by any component or combination of components apt to make the required operational linkage gear mechanisms.
As may be seen in both FIG. 1 and FIG. 3, the linkage arrangement of the present invention preferably includes a guide bracket assembly 02 to help the driver in the driver seat 70 to indicate and select the desired gear position from a set of available gears in the transfer case 30. The assembly bracket 02 is also provided with a plastic guide bracket 02’ which is assembled to bracket 02’’ to reduce the rattling noise that may arise during the high speed running of the vehicle 100. With such configuration, the rattling noise during changeover from one drive mode to another is reduced.
The guide bracket assembly 02 is firmly assembled to center console 50 using bolts 07. The bolts 07 are covered using plastic cover 01 to enhance the aesthetic environment in the cabin. However as well known in the art, this arrangement may be alternatively connected by any component or combination of components apt to make the required operational linkage gear mechanisms.
As one skilled in the art will readily understand, a common automobile with 4x4 drive option will offer the driver 4 different drive modes to choose from. They are in general, 4H or 4HIGH for better distribution of available torque without compromising on vehicle speed, 4L or 4LOW for enhancing the available torque at the cost of vehicle speed, 2H or 2HIGH for normal 4x2 mode and N or NEUTRAL to prevent accidental shifting from High to Low modes, which may damage the gearing in transfer case.
When gear shift lever, referred to as lever 19 if shifted to desired drive mode the movement of the lever 19 is mechanically transferred to subsequent rotational motion of the pivot link 03 about the rivet axis of the pin 08. The pivot link 03 connected at the other end to adjustable link rod 11, transfers its rotational movement to the shift shaft lever 06 using the adjustable link rod 11. Such configuration of the adjustable link rod 11 provided rigid linkage configuration to overcome drawbacks of the cable linkages and
10

also provides flexibility to accommodate the inevitable variations. Due to rotational movement of the shift shaft lever 06 which is connected to the transfer case assembly 30 (FIG. 3), the gearing in the transfer case is shifted to engage the drive mode as desired by driver. As understood by one skilled in the field of mechanical engineering, the present invention advantageously uses the concepts of mechanical advantage and leverage by adjusting the length of the various linkages involved in the MSL to optimize effort required for required for shifting the gears.
The present invention may advantageously be used in a vehicle having a preexisting transfer case system but lacking a means to shift the gears in the transfer case to choose different drive modes. According to embodied illustration, present invention provides a method for shifting from different drives using a set of mechanical linkages by understanding that the vehicle already has a transfer case system and other drive line systems of the vehicle. As one skilled in the art will readily understand, the linkage assembly according to the present invention provides for the purely mechanical transfer of the shifting signal from driver to the transfer case of the vehicle.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
Advantages:
The present disclosure provides system for changing drive modes of a vehicle that mechanically operates to change drive mode of vehicle from one drive mode to another, without utilizing complex, expensive and delicate and unreliable electrical/ electronic elements that are expensive and not reliable. Further, the system for changing drive modes of a vehicle provides smooth changeover while shifting from one drive mode to another. Furthermore, the system for changing drive modes of a vehicle reduces rattling noise during changeover from one drive mode to another.
Referral Numerals:
11

Reference Number Description
100 vehicle
01 plastic cover
02 guide bracket assembly
02’ plastic guide bracket
02’’ bracket
03 pivot link
05 bush
05’ step bush
06 shift shaft lever / connecting lever
06’ pin
07 bolts
08 pin
09 mounting bracket
10 dampening pad
11 adjustable link rod
12 and 13 provisions to adjust length of adjustable link rod 11
15 bolt
16 lock pin
19 gear shift lever
30 transfer case assembly
50 center console
60 main gear shift lever
70 driver seat
90 mechanical shift linkages (MSL) system
12

WE CLAIM:
1. A system (90) for changing drive modes of a vehicle, said system (90)
comprising:
• a guide bracket (02’) mounted over a floor (40) of the vehicle, wherein said guide bracket (02’) has a slot “S” configured thereon;
• a lever (19) adapted to be partially received and move within said slot “S”;
• a pivot link (03) pivotably supported underneath said guide bracket (02’), said pivot link (03) connected to said lever (19) and adapted to swivel as said lever (19) moves within said slot “S”;
• an adjustable link rod (11) securely connected to said pivot link (03) and adapted to move as said pivot link swivels; and
• a shift shaft lever (06) securely mounted over and adapted to move with said adjustable link rod (11) as actuation forces are transferred from said lever (19) to said shift shaft lever (06) via said pivot link (03) and said adjustable link rod (11) to cause actuation of said transfer case assembly disposed underneath said floor (40) for changing drive modes of the vehicle.

2. The system (90) as claimed in claim 1 further comprising a mounting bracket (09) disposed underneath said guide bracket (02’) and mounted on said floor (40), said mounting bracket (09) adapted to pivotably support said pivot link (03).
3. The system (90) as claimed in claim 2, further comprising a dampening pad disposed between the mounting bracket (09) and said floor (40) adapted to dampen the vibrations and rattling noises.
4. The system (90) as claimed in claim 2, wherein said pivot link (03) has a bush (05) configured thereon adapted to receive a pin (8) supported by said mounting bracket to facilitate pivotable movement of said pivot link (03) with respect to said mounting bracket (09).
13

5. The system (90) as claimed in claim 4, wherein said bush (05) is a stepped bush.
6. The system (90) as claimed in claim 1, wherein said adjustable link rod (11) is provided with provision for adjusting length thereof to accommodate the inevitable variations during assembly.
7. The system (90) as claimed in claim 1, wherein said adjustable link rod (11) is configured of threaded elements.
8. The system (90) as claimed in claim 1, wherein said adjustable link rod (11) is hydraulic piston cylinder arrangement.
9. The system (90) as claimed in claim 1, wherein said shift shaft lever (06) has a pin (06’) configured thereon that engages with gears in the gearbox transfer case assembly for actuation thereof for changing drive modes.
10. The system (90) as claimed in claim 1, wherein said lever (19) is connected to said pivot link (03) using bolt 15 and lock pin 16 arrangement.