Note: Descriptions are shown in the official language in which they were submitted.
CA 02304545 2000-04-11
Patent Application: ANTI-ROLLOVER DEVICE
Inventor: BIBHUTI BHUSAN BARDHAN
Page - 2 (of 6)
Background of Invention
Rollover of vehicles (especially minivans, sports utility vehicles or SUV's,
etc.) is a major cause of road
accidents causing property damages, personal injuries and fatalities, etc..
Generally, a rollover (that is,
tripping over or turning over of a vehicle on its side) is caused by excessive
thrust of the centre of gravity
of the vehicle pushing it beyond the points of contact of tires with the road
surface on the side of the
potential rollover when the vehicle is turned more sharply and at a higher
speed than what may be safe
under the circumstance, taking into account such factors as the speed of the
vehicle at the time (thereby
providing greater forward thrust on the centre of gravity of the vehicle),
distribution of loads in the vehicle,
especially pushing the centre of gravity at a higher level (e.g., by more
passengers or loads, etc. inside or
above the vehicle, etc.), grip of tires on the road surface, primarily
preventing the skidding of the tires (that
might have, ironically in the present circumstance, prevented the centre of
gravity of the vehicle to go
outside the outer limits of the tires, and thus prevented the rollover!),
etc..
Such a rollover is effected, generally speaking, when a vehicle turns on its
wheels more sharply
than would allow the centre of gravity of the vehicle to anchor the vehicle
safely on the road (that is, its
force passing between the two sets of tires on each side). If at any time this
thrust of centre of gravity
happens to pass over (the forward thrust) and fall on (downward pull) the
outer side of the limit of the area
between the said set of tires on each side, there would be a chance or
possibility of a rollover. There is more
likelihood of this happening under such circumstances as when the turning of
the wheels is sharper, or the
speed is greater, or the centre of gravity of the vehicle is pushed higher,
say, by distribution of loads, the
road condition or the state of the tire or tires does not allow for skidding,
etc., etc..
Thus, in short, generally speaking, possibility of automobile rollover kicks
in once a certain
sharpness of turning is exceeded, and then it is mainly a function of
sharpness of the turning of the vehicle
and its speed relative to the said sharpness of turning as well as the
relative position, especially height and
the nearness to the side of a potential rollover, of the centre of gravity of
the vehicle at a given time. In such
situations a potential rollover can generally be avoided either by reducing
the speed of the vehicle or by not
going over a safe sharpness of its turning. Since the latter case usually
prevails in a rollover, the present
invention mainly draws on and deals with this eventuality. However, another
possible way of avoiding a
rollover is automatic reduction of the speed of the vehicle as the sharpness
of the turn is increased by the
driver (maybe inadvertently) beyond the safe sharpness of turning under the
prevailing condition. As a
further, and compromising, alternative (using both priorities of speed and
sharpness of turning, so to say),
as a more than safe sharpness of turning is approached (by the driver, maybe
inadvertently), the computer
would prompt the steering wheel to present greater and greater (that is,
increasing degree of) difficulty or
hardness in fuming while automatically reducing the speed of the vehicle until
it reaches a safe level
commensurate with the attempted sharpness of turning. All such devices or
mechanisms would be deemed
to be within the purview of this invention as these can be easily achieved by
the computer used in this
invention using state-of the-art technology of common knowledge.
The present invention is primarily intended to prevent or minimize such
automobile rollovers by
calculating (with the help of a computer, etc.) the safe upper limit of
sharpness of turning of the wheels at
any given time taking into account such factors as the prevailing speed of the
vehicle, spread of loads of the
vehicle, etc. or, even, the friction level between the tires and the road
surface, etc. (for example, a slippery
road surface, or poor contact or gripping of tires on the road surface, etc.,
may cause a skidding of the tires
and may thus avoid a rollover under certain circumstances - which of these two
hazards is a Beater evil is
another question, of course), and then preventing, or increasing (gradually or
at once) resistance to, the
turning of the vehicle by the driver beyond the said upper limit of the
sharpness of turning of the wheels.
There may be an overriding mechanism to disable or disengage this feature of
the present
invention as and when desired (e.g., by professional drivers, for stunt
effects, etc.).
It should be noted that if, theoretically, the grip of the tires on the road
is absolute, there is always
a theoretical speed high enough to trip the centre of gravity of the vehicle
outside the said points of contact
(BB or CC) of the tires with the road surface (BC, BC1, BC2) when the vehicle
is turning sharply enough,
and thus to cause a rollover. The higher the speed of the vehicle, the higher
the prevailing level of its centre
of gravity, and greater the sharpness of turning, the more is the possibility
of rollover, of course.
CA 02304545 2000-04-11
Patent Application: ANTI-ROLLOVER DEVICE
Inventor: BIBHUTI BHUSAN BARDHAN
Page - 3 (0~6,~
Description of Invention
Like numbers in parenthesis here refer to like numbers in the drawings in the
DIAGRAMS (A, B, and C).
Vehicle (1) has a centre of gravity (3). This vehicle may be empty or may have
added loads (11).
Vehicle with added load (111) also has its centre of gravity (3), but the
latter may be at a different point
than in the vehicle without this added load, depending on distribution of this
load. Typically, in a vehicle
( 1 ) the centre of gravity (3) is at a lower point than the anatomical centre
of the vehicle (2) because most of
the weight of the vehicle is generally at its lower part.
However, when the vehicle (1) is loaded (111), either with materials or
people, or both, the loads
are placed at a higher level than the level of the original centre of gravity
(3) of the vehicle when empty (1),
thus driving this centre of gravity (3) higher than what was before this load
was added. This makes the
vehicle more susceptible to rollover. This is because the rollover takes place
when the centre of gravity
happens to exert its force on a line of force of gravity (5) on the outside of
the points of contact of the tires
(B or C in DIAGRAM - A, and BB or CC in DIAGRAM - C, depending on the side of
rollover) with the
road surface (BC in DIAGRAM - A, and BC 1 and BC2 in DIAGRAM - C). This is
typically the case
when the vehicle is turning at a higher speed, the centre of gravity tending
to be forced outside of the said
crucial points of contact of the tires with the road surface. This happens
more and more easily as the spread
of load in the vehicle pushes the centre of gravity higher and as the vehicle
is driven faster when turning.
This is also the case when the tire is gripping the road surface more firmly
without allowing these points of
contact (B or C) to skid and, thus, to shift to the outer side of the line of
force of gravity (5).
Like when animals are running, when the automobile is moving, it is all the
time trying to catch its
own centre of gravity thrust forward. However, since this centre of gravity
cannot, normally, move in front
outside of the front tires it does not roll over frontally. But when the
automobile turns sideways sharply,
this centre of gravity, helped by the line of forward thrust of the centre of
gravity (55) of the vehicle falling
on the outer side of the points of contacts of the tires with the road surface
on the side of potential rollover
(BB in this instance in DIAGRAM - C) in case of a sharp enough turning, may
tip over to the outside of
the two side tires of the opposite side of the direction of the said turning,
thus allowing and helping the
automobile to rollover on that side.
Therefore, one sure way of preventing such rollover (sideways) is to prevent
or avoid the
automobile turning any more sharply than is safe, namely, in this instance,
preventing or avoiding the
prevailing centre of gravity (3) moving sideways beyond the above said crucial
points of contact (BB or
CC) of the tires with the road surface (BC, BC1, BC2) (or, alternatively, by
automatic reduction of the
speed to a level safe enough for the sharpness of the turning at the time).
This goal can be achieved by a computer (7) calculating the risk factors
prevailing at any given
instant, such as the centre of gravity (taking into account the added loads -
calculating from the present
weight of the automobile minus the weight of the automobile when empty, or
even calculating the general
position of the centre of gravity from data showing how easily the automobile
is tending to sway sideways
with any amount of turning at any given point in time, especially immediately
before the potential rollover
could possibly take place and before and during the anti-rollover device of
the present invention comes into
play, the speed of the car, the road condition (especially slippery condition
that may allow skidding but,
thus, avoid rollover), etc..
Then this computer activates a mechanism (say, fitted at the end of the
steering wheel) that would
prevent the sharpness of turning of the wheels beyond a certain limit that may
cause a rollover at any
particular point in time under a given circumstance, or, alternatively, cause
an automatic reduction of the
speed to a level safe enough for the approaching intended sharpness of the
turning at the time, taking the
steering wheel through an increasing amount of difficulty (such a stiffness)
in turning as a safe sharpness in
turning (critical and commensurate with the prevailing or ultimate speed of
the vehicle) is gradually and
eventually reached.
This anti-rollover device (or AROD) may be operated in several ways, including
by being totally
disabled or overridden, or by disallowing any further turning whatsoever
beyond the safe limit as described
and explained above, or by making it gradually and increasingly harder and
harder, after a certain
predetermined point, for the driver to turn the steering wheel to allow,
thereby, the automobile to turn
beyond this safe limit of sharpness of turning eventually, or by automatic
reduction of the speed of the
vehicle to a level safe enough for the attempted sharpness of the turning.
There may be accompanying
warning signals, such as with sound, light, etc..
