FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003


COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
An improved bus roof structure
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 Chandra Prakash Mishra both 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 particularly describes the invention and the manner
in which it is to be performed.

FIELD OF INVENTION
This invention relates to the vehicle body building and more particularly it relates-to an improved bus roof structure of a vehicle.
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. This property 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 interior space for safeguarding the passengers. Further findings and investigations of the bus rollover accidents have shown that the structural strength of the roof plays very important role for maintaining the integrity of the bus in the event of rollover.
OBJECTS OF THE INVENTION
The main object of the present invention is to provide an improved bus roof structure. Another object of the present invention is to provide an improved structure for a bus roof which is simple in construction and cost effective.
STATEMENT OF INVENTION
Accordingly the present invention discloses an improved bus roof structure
comprising;
plurality of longitudinal members disposed along the vehicle length;
plurality of cross members disposed along the width of the vehicle;

plurality of diagonal members disposed diagonally in the rectangles formed by intersection of said longitudinal members and said cross members, in both directions to facilitate the cross structure configured to form 'Y' shaped structure on top of door aperture and 'W shaped structure in remaining area of bus roof.
DESCRIPTION OF DRAWINGS
Figure-01 shows the prior art roof structure of a bus
Figure-02 shows the roof structure of a bus in accordance with this invention.
BRIEF DESCRIPTION OF THE INVENTION
In accordance with the present invention, an improved roof structure of a bus comprises; plurality of longitudinal members disposed along the vehicle length, plurality of cross members disposed along the vehicle width direction, plurality of diagonal members disposed diagonally in both direction such as to make cross structure, wherein said structure provided therein is configured to make 'Y' and 'W shaped structure on the roof of said vehicle and said Y shaped structure provided on top of the door aperture and W shaped structures is provided in the remaining areas of bus roof, said W shaped members are positioned back to back in the adjacent rows such that they form a chain of diagonal members and distribute the load reactions.
DETAIL DESCRIPTION OF THE INVENTION
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.

Fig 1 shows prior art roof structure of a bus which is an array of longitudinal and transverse members Such roof structure is quite weak in torsional and bending loads. Figure-02 shows the improved bus roof structure in accordance with the present invention.
Now referring to Fig 2 ,in accordance with this invention, an improved roof structure of a bus comprises; plurality of longitudinal members disposed along the vehicle length, plurality of cross members disposed along the vehicle width direction, plurality of diagonal members disposed diagonally in both direction such as to make cross structure, wherein said cross structure provided therein is configured to make 'Y' and 'W shaped structure on the roof of said vehicle and said Y shaped structure provided on top of the door aperture and W shaped structures is provided in the remaining areas of bus roof, said W shaped members are positioned back to back in the adjacent rows such that they form a chain of diagonal members and distribute the load reactions.
The said diagonal members in the roof structure of the said vehicle are provided to improve its torsional strength. The diagonal members are configured to be arranged in such a manner that they achieve the required torsional strength. Preferably said "Y" shaped structure members are located above a lateral opening which cuts across the waistline level as shown in fig 2 such as door apertures. The said waistline level is at the lower end of the window apertures which contains a structural member connecting the side wall of the bus structure. The said diagonal members are placed in the rectangles formed by said long member and cross member of said roof structure. The said W shaped members are positioned

back to back in the adjacent rows such that they form a chain of diagonal members and distribute the load reactions.
Both these Y and W shaped members provide a roof structure which is cost effective. They are also simple to construct as they could be prepared by using the structural members used for making the longitudinal & cross members of bus roof structure. The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, 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.

WE CLAIM
1. An improved bus roof structure comprising;
plurality of longitudinal members disposed along the vehicle length;
plurality of cross members disposed along the width of the vehicle;
plurality of diagonal members disposed diagonally in the rectangles formed by
intersection of said longitudinal members and said cross members, in both directions
to facilitate the cross structure configured to form 'Y' shaped structure on top of door
aperture and ' W shaped structure in remaining area of bus roof.
2. The improved bus roof structure as claimed in claim \, wherein said 'W shaped structure members are constituted to position back to back in the adjacent rows configured to form a chain of diagonal members.
3. The improved bus roof structure as claimed in claim 2, wherein said diagonal members are configured to distribute load reactions and improve torsional strength.
4. The improved bus roof structure as claimed in claim 1, wherein said 'W shaped structure members are constituted to position in parallel in the adjacent rows configured to form series of'W shaped structure member.
5. The improved bus roof structure as claimed in claim 1 or 4, wherein said 'W shaped structure members are disposed in entire or part of the roof structure.
6. The improved bus roof structure as claimed in claim 5, wherein said 'Y' shaped structure is disposed in entire or part of the roof structure.

7. The improved bus roof structure substantially as herein described with reference to accompanying drawings.
Dated this 2nd day of March 2009