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 Sliding Door Assembly For Vehicles
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
Mahesh Mungi
an Indian national
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
&
Avinash Tabhane
an Indian national
of Altair Engineering (India) an Indian company
having its registered office at 5th floor, B block, Mercury, Sarjapur Road,
Marthahalli, Banglore, Karnataka, 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 door assembly of vehicles and more particularly it relates to an improved sliding door assembly for vehicles.
BACKGROUND OF INVENTION
Vehicles are provided with sliding door for access to the rear part for passengers / goods in order to save the operating space compared to a conventional turning door. The slide door is provided with rollers at top and bottom for smooth sliding. These rollers are provided with guide rails for appropriate movements. These guide rails are located on roof structure & floor structure.
Conventionally the sliding door bottom guide rails are provided below the floor structures. However due to packaging constraints sometimes these guide rails have to be provided above the floor structures. However such an arrangement is very weak in lateral strength. In such situation the sliding door does not exhibit adequate strength under the influence of lateral forces. Under the influence of lateral forces. the roller rolls in forward direction till the end of the guide rails and then disengages from the guide rails at the end of the travel. Upon disengagement of the said rollers with the said guide rails, the sliding door looses its support and results into excessive intrusion inside the passenger compartment. Therefore it is important to prevent separation of the door rollers from the guide rails. In order to address above said disadvantages, improved sliding door assembly for vehicle is developed which prevents loss of integrity of the rollers with the guide rails and improves lateral strength of the sliding doors.
OBJECTS OF THE INVENTION
The main object of the present invention is to provide an improved sliding door assembly for vehicles.

Another object of the present invention is to provide an improved sliding door assembly for vehicles which is simple in construction and cost effective.
STATEMENT OF INVENTION
An improved slideable door assembly of a vehicle comprising
sliding door fitted on a vehicle,
top guide rail provided at upper end of vehicle structure,
bottom guide rail provided on top of the floor structure.
said sliding door having top and bottom roller assembly operably engaged with said top guide rail and bottom guide rail respectively for smooth sliding of said sliding door throught the sliding stroke.
said top guide rail and bottom guide rail having stopper bracket disposed on front end at the end of travel and,
said stopper bracket is attached to vehicle structure enabling to improve the strength of said door assembly under the influence of the lateral forces.
The door assembly, in accordance with this invention, wherein said stopper bracket facilitates integrity and exhibit adequate strength to said sliding door by preventing the detachment of said top and bottom roller assemblies from said guide rails.
The door assembly, in accordance with this invention, wherein said stopper bracket is attached to the vehicle structure preferably with the help of welding.
The door assembly, in accordance with this invention, wherein said top and bottom roller assembly is provided at top and bottom end of said sliding door respectively.
The door assembly, in accordance with this invention, wherein said top and bottom roller assemblies are provided on the inner side of said sliding door.

The door assembly , in accordance with this invention, wherein said roller assembly of said sliding door roll in forward direction till the end of the guide rails and is stopped by said stopper bracket at the end of the travel under lateral forces.
BRIEF DESCRIPTION OF INVENTION
An improved sliding door assembly for vehicles comprises; sliding door (2) fitted on a vehicle (1), top guide rail (3) provided at upper end of vehicle structure and bottom guide rail (4) provided on floor structure (5) for smooth sliding and guiding said sliding door throughout the sliding stroke, wherein said sliding door (2) having top and bottom roller assembly (6) disposed on inner side at top and bottom end operably engaged with said top guide rail and bottom guide rail respectively for effective sliding, said bottom guide rail (4) provided on top of the said floor structure (5). said top guide rail (3) and bottom guide rail (4) having stopper bracket (7) disposed at front end. said stopper bracket (7) is attached to vehicle structure with the help of welding enabling to improve the strength of the door assembly under the influence of the lateral forces.
DETAILED DESCRIPTION OF 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.
Figure - 01 shows side view of a vehicle with sliding door.
Figure - 02 shows the partial side view of a vehicle showing the sliding door
& guide rails at top and bottom end, Figure - 03 shows side view of the sliding door as seen from inside of a vehicle. Figure - 04 shows the partial top view of the sliding door as seen from inside the
vehicle. Figure - 05 shows the partial top view of the sliding door as seen from inside the
vehicle under the influence of lateral forces.

Figure - 06 shows the partial top view of the sliding door as seen from inside the
vehicle, provided with an end stopper bracket, in accordance with this
invention. Figure - 07 shows the partial top view of sliding door as seen from inside the
vehicle under the influence of lateral forces in accordance with this
invention. Figure - 08 shows the isometric view of the bottom guide rail provided with an end
stopper bracket in accordance with this invention.
Now referring to figures - 01 to 08, an improved sliding door assembly for vehicles comprises; sliding door (2) fitted on a vehicle (1). top guide rail (3) provided at upper end of vehicle structure and bottom guide rail (4) provided on floor structure (5) for smooth sliding and guiding said sliding door throughout the sliding stroke, wherein said sliding door (2) having top and bottom roller assembly (6) disposed on inner side at top and bottom end operably engaged with said top guide rail and bottom guide rail respectively for effective sliding, said bottom guide rail (4) provided on top of the said floor structure (5). said top guide rail (3) and bottom guide rail (4) having stopper bracket (7) disposed at front end. said stopper bracket (7) is attached to vehicle structure with the help of welding enabling to improve the strength of the door assembly under the influence of the lateral forces.
Referring to figure-01 which shows side view of a vehicle (1). The said vehicle is fitted with a sliding door (2).
Referring to figure-02 which shows partial side view of the said sliding door. The said sliding door (2) rolls on the said top guide rail (3) and bottom guide rail (4) provided on the floor structure (5).
Referring to figure-03 & 04 which show the side and top view of the said sliding door (2), wherein said sliding door (2) comprises top roller assembly and bottom roller assembly (6) provided on the inner side of the said sliding door (2) at top and bottom end. During normal operation, said top roller assembly and bottom roller

assembly (6) slides on the said top guide rail (3) and bottom guide rail (4) respectively. The said top guide rail (03) provided on upper end of vehicle structure and said bottom guide rail (04) is provided on top of the vehicle floor structure (5).
Referring to figure-05 which shows top view of the said slide door arrangement in deformed condition. Under the influence of the lateral force, the said top and bottom roller assembly (6) of said sliding door (2) comes out of the said guide rails to disengaged position (6a) and the said sliding door (2) gets deformed to (2a) which poses hazard to the occupant of the vehicle
Referring to figure- 06 which shows top view of the of the said sliding door arrangement wherein said top guide rail (3) and bottom guide rail (4) comprises a stopper bracket (7) at its front end at the end of travel to prevent the detachment of the said bottom roller assembly (6) from the said said top guide rail (3) and bottom guide rail (4). under the influence lateral force.
Refering to figure-07 which shows top view of the said slide door arrangement as seen from inside of a vehicle under the influence of lateral forces. The said stopper bracket (7) provided on the said guide rails (3,4) at the front end prevents the detachment of the said bottom roller assembly (6) from the said guide rails (3,4) and keep said top and bottom roller assembly in original position under the influence of the lateral force and avoids the intrusion of the said sliding door (2) in to passengers compartment and enabling the side door to be deformed and take the deformed shape (2b) as shown.
Figure 08 shows isometric view of the said stopper bracket (7) provided at front end of the said guide rails (3,4). The said stopper bracket (7) is attached to vehicle structure with the help of conventional process such as welding. The said stopper bracket (7) provided at the front end of said guide rails (3,4) facilitates the integrity of said bottom roller assembly (6) and said guide rails (3,4) and said sliding door (2) exhibit adequate strength under the influence of lateral forces. Under the force from lateral direction, said top and bottom roller assembly (6) of the said sliding

door (2) roll in forward direction till the end of the said top (3) and bottom guide rail (4) respectively and is stopped by said stopper bracket (7) provided on the said guide rails (3,4) at the end of the travel. The said stopper bracket (7) prevents the disengagement or separation of the said top and bottom roller assembly (6) from said said top guide rail (3) and bottom guide rail (4) respectively and retain the engaged position with respective guide rails, therefore retains the strength of the sliding door (2) under lateral forces and avoids the excessive intrusion of the sliding door (2) inside the passenger compartment,
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 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 slideable door assembly of a vehicle comprising
sliding door fitted on a vehicle.
top guide rail provided at upper end of vehicle structure,
bottom guide rail provided on top of the floor structure,
said sliding door having top and bottom roller assembly operably engaged with said top guide rail and bottom guide rail respectively for smooth sliding of said sliding door throught the sliding stroke,
said top guide rail and bottom guide rail having stopper bracket disposed on front end at the end of travel and.
said stopper bracket is attached to vehicle structure enabling to improve the strength of said door assembly under the influence of the lateral forces.
2. The door assembly as claimed in claim 1. wherein said stopper bracket facilitates integrity and exhibit adequate strength to said sliding door by preventing the detachment of said top and bottom roller assemblies from said guide rails.
3. The door assembly as claimed in claim 1, wherein said stopper bracket is attached to the vehicle structure preferably with the help of welding
4. The door assembly as claimed in claim 1. wherein said top and bottom roller assembly is provided at top and bottom end of said sliding door respectively.
5. The door assembly as claimed in claim 1, wherein said top and bottom roller assemblies are provided on the inner side of said sliding door.

6. The door assembly as claimed in claim 1. wherein said roller assembly of said sliding door roll in forward direction till the end of the guide rails and is stopped by said stopper bracket at the end of the travel under lateral forces.
7. An improved slideable door assembly of a vehicle substantially as hereinabove described is with reference to the accompanying drawings.