FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10; rule 13)


TITLE OF THE INVENTION An Improved Side Structure Of A Bus
APPLICANTS
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
Samir Joshi and C Anilkumar
Both are Indian Nationals
of TATA MOTORS LIMITED an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification describes the invention.

FIELD OF INVENTION
This invention relates to the vehicle body building and more particularly it relates-to an improved side structure of a bus.
BACKGROUND OF INVENTION
Buses or coaches are widely used for public transportation. The centre of gravity of a bus is located quite high from the road surface. Location of centre of gravity at height makes the bus vulnerable for roll over type of accidents. The bus structures are therefore required to be adequately robust to maintain the space and integrity of its interiors for safeguarding the passengers. Further findings and investigations of the bus rollover accidents have shown that the structural strength of the side structure plays very important role for maintaining the integrity of the bus in the event of rollover.
Conventionally the side structure of a bus is weak to sustain the loads generated in a roll over due to
(a) - weak connection of the lower longitudinal members with the stronger chassis members. The cross members used for connecting the lower longitudinal members to the chassis members are weak & the manner of its joining with the lower longitudinal member makes it vulnerable for failure in smaller shear loads. In case of roll over, the entire side structure looses connection to the chassis members due to failure of these cross members resulting in unpredictable behavior of the floor structure as well of its dependent structural members. These connections are the only link of the side structure with the chassis members. Therefore the strength of the side structure is dependant on the strength of these connections. Weaker connecting links are as good as absence of the links which makes the entire side structure as floating structure in space.
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(b)- discontinuous window pillars either rupture of deform excessively in roll over. The point of discontinuity is generally the location for rupture. Also the window pillars are formed with joining of discrete segments. These segments extend upto the waistlevel longitudinal rail & do not have direct connection to the lower longitudinal rail which makes them further vulnerable for excessive deformations, (c )- discontinuous & weak lower longitudinal rails. The lower longitudinal rail is a very critical side structure member as it forms a lower extremity of the passenger compartment. However it is not designed as a load carrying member & therefore it is vulnerable for excessive deformations & failures under roll over conditions. Such a non integrated side structure results into excessive intrusions in the passenger compartment leading to serious injuries to the occupants in the event of roll over. Crash performance of such a structure is not predictable.
OBJECTS OF INVENTION
The main object of the present invention is to provide an improved side structure of a bus.
Another object of the present invention is to provide an improved side structure for a bus which is robust to maintain the space and integrity of its interiors for safeguarding the passengers.
Another object of the present invention is to provide an improved side structure for a bus which is simple in construction and cost effective.
BRIEF DESCRIPTION OF DRAWINGS
Figure-01 shows the side structure of a bus in accordance with this invention. Figure-02 shows the details of the typical joinery between the first cross member &
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lower longitudinal rail. Figure-03 shows an alternate execution of an improved side structure of a bus in accordance with this invention.
BRIEF DESCRIPTION OF INVENTION
In accordance with the present invention, improved side structure of a bus comprises; an upper chassis member, a lower chassis member, plurality of first & second cross members, a continuous lower longitudinal rail, a waist level longitudinal rail, a cant rail, plurality of vertical members for connecting the lower longitudinal rail & the second cross members, plurality of continuous window pillars and floor panel for mounting of seat structures.
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same.
Now referring to Fig 01 to 03 , in accordance with this invention,
Improved side structure of a bus comprises; a lower chassis member (1), an upper chassis member (2), a lower longitudinal member (3), waist level longitudinal member (4), a cant rail (5), plurality of first cross members (6) connecting the said upper chassis member (2) to the said lower longitudinal member (3), plurality of vertical members (7) connected to the said lower longitudinal member (3), plurality of second cross members (8) which connect the said upper & lower chassis members (1,2) and extended further to connect with the said vertical members (7), plurality of window pillars (9) which extend from the said cant rail (5) to the said lower longitudinal member (3), floor panel (10) which is connected & spread over the said
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upper chassis member (2) & the said lower longitudinal member(3) , seat structure (11) installed on the said floor panel (10). The said side structure is covered from inside & outside suitably to form the passenger compartment as well as to improve aesthetics.
The said lower longitudinal member (3) has been designed for side & bending loads which improve retention of the side structure in the event of roll over.
The arrangement of the said lower and upper chassis members (1,2), first and second cross members (6,8) , window pillars (9), said cant rail (5) when integrated with corresponding members of opposite end side structure, makes a strong box shaped passenger compartment which improves its robustness under roll over condition. A continuous lower longitudinal member (3) is provided along the vehicle length, to which the said pluralities of first cross member (6) are connected.
Plurality of Continuous window pillar (9) is provided to connect said cant rail (5) to the lower longitudinal member (3) for improving the strength of the side structure. This helps in minimizing the structural deformations in the event of roll over.
Fig 02 shows details of the connection between the said first cross member with the said vertical member.
Now referring to Fig 03 which illustrates another embodiment of the present invention, an intermediate longitudinal member (12) is provided between the said lower longitudinal member (3) and said waist level longitudinal member (4). The said intermediate longitudinal member (12) is provided for outboard mounting of the seat structure (11) and such an additional longitudinal member further improves the stiffness & strength of the side structure. The diagram shown illustrates the left side structure of the bus and right side structure is mirror opposite of the said left side structure.
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The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration oniy, and that numerous alterations and modifications and combinations may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.