FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL 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
Richard Morris a British national
of Airbag Disposal & Recycling Services Ltd,
at Sparkenhoe House, Southfleld Road, Hinckley,
Leicestershire, LE10 1UB, England,UK.
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 safety system of automobile and more particularly it relates to the steering wheel with integrated safety feature of an automobile.
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 forces between the driver & the steering system.
Conventionally the steering wheel is made stiff in order to avoid excessive vibration when the engine is running slowly 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.
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.


BRIEF DESCRIPTION OF THE INVENTION
In accordance with the present invention, the steering wheel with integrated safety feature comprises hub (2) which is provided for connecting the steering wheel to the steering column with the help of fasteners, rim (1) for providing input to turn the steering system, plurality of upper spokes(3a,3b) and lower spokes (3c,3d) for connecting the said rim (1) to the said hub (2) wherein at least two said lower spokes (3c,3d) comprises a weak zone for reducing the stiffness of the steering wheel. The said weak zone is in the form of groove (4). Said lower spokes comprises locking links (5) disposed across the said lower spokes attached. The said locking link is attached at the two ends with the said spokes.
The said spokes comprises plurality of pin member (6) for attaching the said locking link (5). The said locking link (5) comprises first member (8a) and second member (8b) joined together at the centre such that it provides a space or cavity (9) to house an actuator which facilitates said first and second member to move in opposite inward direction (10). Said locking links are attached together with the help of fasteners (11). Said first and second member comprises plurality of slots (7) at the end for connecting with the said lower spokes. Said first member (8a) and second member(8b) comprises plurality of slots (12) which facilitates the movement of said first and second member in opposite inward direction, without separation, during movement for allowing the said lower spokes to move in the downward direction during the impact and therefore reducing the bodily injuries to the driver .


BRIEF DESCRIPTION OF INVENTION
Figure - 01 is a prior art steering wheel structure.
Figure - 02 shows the steering wheel lower spokes provided with weak zone to
promote its deformation at low forces to reduce bodily injury to an occupant.
Figure - 03 shows a lower spoke provided with a locking link.
Figure- 4 shows the details of the locking link.
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,
Referring to Figure-01 which shows structure of a prior art steering wheel in a 12 o'clock position that is a normal driving position. The steering wheel structure consists of rim (1), hub (2) and plurality of spokes (3a, 3b, 3c, 3d). The said rim provides input to turn the steering system. Hub is provided to connect the steering wheel to the steering column through fasteners. Spokes are provided to connect the rim to the hub. The turning movement applied of the rim is transferred to the hub through these spokes. Spokes 3c & 3d are the lower spokes. In 12 o'clock position of the steering wheel, it exhibits the stiffest configuration on account of the lower spokes which results into bodily injury to the occupants.
Now referring to figure -02 to 04 , Steering wheel integrated with safety feature comprises hub (2) which is provided for connecting the steering wheel to the steering column with the help of fasteners, rim (1) for providing input to turn the steering system, plurality of upper spokes(3a,3b) and lower spokes


(3c,3d) for connecting the said rim (1) to the said hub (2) wherein at least two said lower spokes (3c,3d) comprises a weak zone for reducing the stiffness of the steering wheel. The said weak zone is in the form of groove (4). Said lower spokes comprises locking links (5) disposed across the said lower spokes attached. The said locking link is attached at the two ends with the said spokes. The said spokes comprises plurality of pin member (6) for attaching the said locking link (5). The said locking link (5) comprises first member (8a) and second member (8b) joined together at the centre such that it provides a space or cavity (9) to house an actuator which facilitates said first and second member to move in opposite inward direction (10). Said locking links are attached together with the help of fasteners (11). Said first and second member comprises plurality of slots (7) at the end for connecting with the said lower spokes. Said first member (8a) and second member(8b) comprises plurality of slots (12) which facilitates the movement of said first and second member in opposite inward direction without separation during movement for allowing the said lower spokes to bend in the downward direction during the impact and therefore reducing the bodily injuries to the driver .
The steering wheel is provided with a plurality of spokes such that it provides stiff structure in a position known as 12 o'clock position or a normal driving position. This may be the stiffest configuration of the steering wheel structure. In the event of crash, if the driver hits the steering wheel, either directly or through an airbag, the spokes provide necessary strength to the rim and may prevent or limit its deformation.
Said lower spokes comprises weak zone for allowing the said lower spokes to bend in the downward direction at low forces so as to reduce bodily injury with the driver interaction. However such weak zone provided in the said lower spokes (3c,3d) will reduce the resonance frequency of the steering wheel and at low engine speeds , the said steering wheel would vibrate significantly to


irritate the driver. Therefore an additional locking link (5) is provided across the weak zone to make the structure stiff enough as long as the locking link is in place in normal driving condition.
During the impact, when said locking link (5) is detached from the said lower spokes (3c,3d) exposing the said groove(4) provided therein allowing the said lower spoke to bend downward at the said groove and reducing the bodily injuries to the driver. Thus the steering wheel structure acquires dual stiffness. The locking links are provided with attachment means in such a way that they could be detached from the said lower spokes with an actuating mechanism. After the said locking link (5) detachment, said lower spokes attains the weak structure which allows to bend said lower spoke in downward direction that is not harmful to the driver in the event of vehicle crash.
Said lower spokes (3c & 3d) provided with weak zone in form of a groove (4) reduces the stiffness of the steering wheel and therefore bodily injury to the driver. It is possible to provide variety of shapes of the groove to suit the required stiffness and manufacturing technology. However with this weak zone the steering wheel reduces its resonance frequency likely to make it vibrate excessively during low engine rpm. This would be an irritant to driver during driving.
In order to increase the stiffness of the steering wheel, additional locking links (5) are connected to said lower spokes across the said groove (4). Said locking link(5) is connected to said lower spokes (3c,3d) with plurality of pins (6) provided on the said lower spokes. The locking link (5) is provided with plurality of slots (7) for facilitating the movement of said first member (8a) and second member (8b) for detachment from the said lower spokes during the crash of vehicle.


The length of said slot (7) is suitably provided to limit extent of deformation of said lower spoke. It is possible to provide a variety of shapes to said slots (7) and fasteners in place of the pins.
Said first member (8a) and second member (8b) are joined at the centre such that it provides a cavity (9) to house a suitable actuator to move said members of the locking link (5) in opposite directions (10) inwards. When the said first member and second member move inwards, the steering wheel spokes stiffness will be reduced due to the exposer of the grooves (4) and they will deform at less force imparted by bodily interaction of driver during the impact. In this inter action the spokes will be deformed downward in relation to the steering wheel plane.
The links are attached together with fasteners (11). Correspondingly slots (12) are provided on the link (8a) to permit movement of these links without separation during this movement.
The actuator can be of variety of types. It can be provided with a pyrotechnic device or can be integrated with an airbag if provided with the steering wheel.
The advantages associated with invention are -
a) It meets the requirements of higher resonance as well as low stiffness selectively,
b) The system provides choice of the stiffness changeover by controlling actuator function,
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.