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


PROVISIONAL SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
"Efficient Way Of Rotating Steering Angle Sensor"
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
Mr. Mahesh Joshi and Mr. Gautam Nahar
both 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
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 provision of efficient way of rotating the Steering Angle Sensor (SAS), through clock spring & steering wheel and is applicable for all vehicles including LCV, MCV, HCV, MUV, passenger Cars.
BACKGROUND OF INVENTION
The Steering Angle sensor (SAS) is one of the sensors required to sense the steering angle of the wheel in Electronic Stability Program[ESP). It senses the steering angle of the wheel and sends signal to the Electronic Control Unit [ECU). Then ECU does calculations and controls the wheel end torque and brakes applied to stabilize the vehicle.
OBJECTS OF INVENTION
The main object of the invention is a SAS mounted on combination switch assembly by SAS mounting plate and that gets rotated through clock spring and therefore, the clock spring gets rotated through steering wheel.
Yet another object of the invention is the design which is very compact and efficient.
Yet another object of the invention is that it is well protected in the nacelle so free from dust and heat zone.
BRIEF DESCRIPTION OF INVENTION
For Electronic Stability Program (ESP), one of the data required is steering angle. It is to control yawning of the vehicle. It is very useful in lane changing, different coefficient of friction condition for all wheels like muddy area, rough roads, snow


fall etc. The steering angle sensor senses the steering angle through clock spring rotated by steering wheel. This gives major advantage of better accuracy with well protected compact design. The SAS is mounted on combi switch assembly only.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a steering wheel arrangement showing the slot in which the clock spring
is positioned;
FIG. 2 is a detailed plan view of the arrangement showing the connector inserted
in the steering wheel slot and the position of clock spring;
FIG. 3 is a elevational view showing the Clock Spring in the slot for steering angle
sensor;
FIG. 4 is showing a Steering Angle Sensor with the projection which gets inserted
in Clock Spring slot (III).
FIG. 5 is an exploded view of an assembly.
DETAILED DESCRIPTION OF INVENTION:
The SAS is required to sense the steering angle. It gives input to ECU. That further stabilizes the vehicle by controlling steering wheel torque and brakes. There are no of ways to mount the SAS in the system like mounted on steering universal joint, mounted on steering column or mounted on steering I-shaft. But all these design have constraints like less accuracy, packaging constraint, coming in heat zone or prone to dust or mud.
The above constraints are overcome by mounting SAS on combi switch assembly. So the design is compact and more accurate now. The SAS is rotated through clock spring which is rotated by steering wheel. Then the signal is given to


Electronic Control Unit for further calculations and control action for stability of the vehicle.
The Figure (5) shows assembly of steering wheel (1), clock spring (2), Steering Angle Sensor (3). Steering Angle sensor (3) is mounted on combi switch assembly through SAS mounting plate. This complete assembly is mounted on steering column. As shown in figure (e), the steering wheel rotates clock spring and clock spring rotates SAS. So design is compact and accuracy is more.
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.
Dated this 31st day of March 2009

TATA MOTORS LIMITED By their Agent & Attorney

Karuna Goleria of DePENNING & DePENNING