FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See Section 10; rule 13)
TITLE OF THE INVENTION
STEERING WHEEL INTEGRATED WITH SAFETY FEATURE
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
INVENTOR
Vinayak S Gogate
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400 001,
Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification describes the invention and the manner in which it is to be performed.

STEERING WHEEL INTEGRATED WITH SAFETY FEATURE
Field of Invention
This invention relates to safety system of an automobile and more particularly it relates to the steering wheel with integrated safety feature.
Background of Invention
In the case of automotive safety, the steering wheel is one of the major causes for bodily injury to driver in the event of a crash. This is on account of stiffness of the steering wheel structure which produces undesirable forces between the driver & the steering system.
Conventionally the steering wheel is made stiff in order to avoid excessive vibrations, when the engine is running at lower speeds, which is a potential irritant to the driver. However such stiff steering wheel structure is not compliant with human body when it hits it during crash and results into injuries. In order to reduce the risk of bodily injury to the human body, the steering wheel is required to be softer such that said steering wheel can produce lower reaction forces during the impact. Therefore it is desirable that the steering wheel spokes deform, absorb energy & provide soft cushioning to the body. It is therefore necessary to provide weaknesses in the steering wheel spokes to promote & control the energy absorption during impact. The invention comprises an improvement in the invention claimed in the specification of the main Indian patent applied for under IP A. No. 461/mum/2008.
Objects of invention
The main object of the present invention is to provide a steering wheel with integrated safety feature of an automobile.

Another object of the present invention is to provide a steering wheel with
integrated safety feature of an automobile which vary the stiffness of a steering
wheel to minimize the bodily injury to an occupant in the event of crash without
affecting its vibration stability.
Yet another object of the present invention is to provide a steering wheel with
integrated safety feature of an automobile which vary the stiffness of a steering
wheel depending on the force exerted on it.
Yet another object of the present invention is to provide a steering wheel with
integrated safety feature of an automobile which is cost effective & easy to
manufacture.
Statement of invention
Steering wheel with safety feature comprising
a hub;
a rim;
plurality of horizontal upper and lower spokes connecting the said rim to the said hub; wherein
said lower spokes having at least one groove portions for reducing the stiffness of the said steering wheel configured to bend downwards under the influence of external force;
bridging plates provided across said grooves and connected to said lower spokes.
Steering wheel, in accordance with present invention, wherein said bridging plates are attached to said lower spoke by shear pins.
Steering wheel, in accordance with present invention, wherein said lower spokes having plurality of grooves.

Steering wheel, in accordance with present invention, wherein said bridging plates are provided on at least one said grooves,
Steering wheel, in accordance with present invention, wherein the shear pins are replaceable.
Brief description of drawings
In accordance to the present invention,
Figure-01 shows the top view of a steering wheel
Figure-02 shows the top view of the steering wheel in accordance with the
present invention
Brief description of invention
In accordance with the present invention, the said lower spokes (3c,3d) each are provided with at least one groove (4) to reduce the stiffness of the steering wheel. The said lower spokes (3c,3d) are provided with bridging plates (5) across the said grooves (4) . The said bridging plates are attached to the said lower spokes (3c,3d) with the help of shear pins (6) or fasteners (6) with predetermined weaknesses.
Detailed description of invention
Now referring to Figure-01 which shows structure steering wheel in a 12 o'clock position that is a normal driving position. The steering wheel structure consists of steering wheel or rim (1), hub (2) and plurality of spokes (3a, 3b, 3c, 3d). The said rim provides input to turn the steering system. Said hub (2) is provided to connect said steering wheel (1) to the steering column through fasteners. Said plurality of spokes (3a, 3b, 3c, 3d) are provided to connect the said rim (1) to the said hub (2). The turning movement applied to said rim (1) is transferred to said

hub(2) through said plurality of spokes(3a, 3b, 3c, 3d), The said spokes (3c & 3d) are the lower spokes and said spokes (3a,3b) are horizontal spokes.
Now referring to figure -02, which shows the top view of the steering wheel arrangement in accordance with the present invention, the said lower spokes (3c,3d) each are provided with at least one groove (4) to reduce the stiffness of the steering wheel. The said lower spokes (3c,3d) are provided with bridging plates (5) across the said grooves (4) . The said bridging plates are connected to the said lower spokes (3c,3d) with the help of shear pins (6) or fasteners with predetermined weaknesses .
During a normal running of the vehicle, the said lower spokes (3c,3d) of said steering wheel (1) behaves like integrated lower spokes due to the bridging plates (5) provided across the said grooves (4). Therefore, though the said lower spokes (3c,3d) are provided with grooves, its effect of lowered stiffness is not felt. Typically the lower stiffness of a steering wheel results into vibrations during normal running which causes irritation to the driver. The lower stiffness of said lower spokes due to said grooves (4) are minimised with the help of said bridging plates (5) provided across said grooves(4).
In the event of crash of a vehicle, the occupant moves forward & contacts the steering wheel. The inertia of the occupant generates force between the steering wheel and the occupant body. When the force exceeds the breaking force of the said shear pins(6), the said bridging plate( 5) disengages from the said lower spokes (3c,3d) of said steering wheel (1). The said lower spokes subsequently looses its stiffness. Therefore the force generated between the occupant and the steering wheel (1) reduces and resulting in less bodily injury to the driver. In the event of crash , the said lower spoke (3c,3d) bends downward at the groove (4). The design engineer can vary the collapse load of the said shear pins (6) and stiffness of the said grooves (4) can be varied to control the injury expected to the driver.

Said lower spokes (3c,3d) having plurality of grooves (4). Said bridging plates (5) are provided on at least one said grooves (4).
The said bridging plates (5) provided over the said grooves (4) connected to said lower spokes with the help of said shear pins(6) which can be chosen to be of replaceable type to alter their collapse charachetristics.
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. Steering wheel with safety feature comprising
a hub;
a rim;
plurality of horizontal upper and lower spokes connecting the said rim to the said hub; wherein
said lower spokes having at least one groove portions for reducing the stiffness of the said steering wheel configured to bend downwards under the influence of external force;
bridging plates provided across said groove portion and connected to said lower spokes.
2. Steering wheel as claimed in claim 1, wherein said bridging plates are attached to said lower spoke by shear pins.
3. Steering wheel as claimed in claim 1, wherein said lower spokes having plurality of grooves .
4. Steering wheel as claimed in claim 1, wherein said bridging plates are provided on at least one said grooves.
5. Steering wheel as claimed in preceding claims, wherein the shear pins are replaceable.
6. Steering wheel with safety feature is substantially as described in the description and as illustrated in the accompanying figures.