FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION "Rubber mounted strut bottom"


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. Raman Pandurangan 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
PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner
in which it is to be performed


FIELD OF THE INVENTION
The invention pertains generally to McPherson strut type arrangement. More specifically, the invention relates to McPherson strut for passenger car segment with the knuckle mounting. The arrangment includes a Bush made of unique rubber material, which is mounted on the bottom portion of the strut, which performs the load and shock absorbing during wheel travel condition, transmitting the lesser load the spring and damper, which consumes the major weight of the strut. The strut is further provided with rod kind of arrangement with a separable nut, for better service ability.
BACKGROUND OF THE INVENTION
This kind of arrangement to reduce the road load transmitted to body by arresting most of the loads in the strut bottom itself, as well providing the cushioning effect while smaller wheel travel, and also provides flexibility in design of spring.
OBJECTS OF INVENTION
The main object of this invention is to reduce the load transmitted to the body by absorbing most of the load in the strut bottom itself.
Yet another object of the invention is tO reduce the weight and cost penalty in the design of spring and damper assembly and provide flexibility in design for packaging.
Yet another important object of the invention is that it will damp the road load and provide better comfort to passengers during smaller wheel travel.
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31 MAR 2009

Yet another object of the invention is that it will provide positive clamping of the rubber bush which provides the cushioning effect.
SUMMARY OF THE INVENTION
This invention is to provide Rubber in strut bottom mount of conventional McPherson strut to absorb road load and vibrations transferred to the body. It also gives the good comfort during wheel travel and cornering. It also reduces the weight of spring and damper.
In conventional design, the strut bottom is rigidly connected to the Knuckle, through which the road load is transferred to spring, damper finally to body. It is noted that major portion of the load is shared by spring and damper, it lead to higher weight and cost. Also the load transferred to the strut top mount is also considerably higher.
In Present invention, major of the wheel load is absorbed at the rubber bottom mount arrangement in the strut bottom itself, gives the better comfort and also considerably reduces the load transferring through the spring and damper which reduces the weight and cost penalty.
The invention possesses numerous benefits and advantages over known conventional McPherson strut arrangement. In particular, the invention utilizes a reliable rubber bush kind of arrangement between the knuckle and strut which allows the maximum road load / shock absorption at the downstage, thereby affording the springs and strut design flexibility as well as user cost reductions. Moreover, the the rubber mounted strut bottom does not require the rubber bush at the top of the strut, and therefore, diminishes bump stopper cup, dust cover and mounting arrangement and its assembly labour requirements and its associated costs. Because of its flexibility and simplicity
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3 1 MAR 2009

in use and installation, the rubber mounting strut bottom of the instant invention realizes a reduction in weight of spring and damper and in the cost of ongoing maintenance.
The advantage of this invention resides in its ability to absorb major load in the strut bottom itself and allow the remaining to top components, which are characterized by the flexibility in design. The mounting arrangement of present invention, given its separately bush and tightening nut, is ideally suited for further serviceability, as well as other applications wherein flexibility and economy is desired.
In addition to the foregoing attributes, the rubber mounted strut bottom possesses numerous other ride and handling benefits over conventional arrangement. Elimination bump stopper at the top of the strut includes the improved comfort at the full wheel travel as compared to those for typical convention arrangement.
The present invention provides that the majority of the wheel load is absorbed at the rubber bottom mount arrangement , gives the better comfort and also considerably reduces the load transferring through the spring and damper which reduces the weight and cost penalty.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a conventional wheel arrangement with McPherson strut assembly of a
vehicle.
FIG. 2 is a front plan view of the McPherson strut bottom of Existing conventional
arrangement;
FIG. 3 is a front plan view of the New Rubber mounted strut bottom;
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31 MAR 2009

DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the drawings and, in particular, with reference to FIGS 1-3, FIG 1 shows the Conventional McPherson strut comprises a strut(damper) 1 ,spring 10, Bump stopper (at top) (not shown) , spring top seat 14, spring bottom seat 15, The strut is mounted at two points, one at top (body), called as strut top mount 16 and another at bottom (to Knuckle 7), called as strut bottom mount 17. The spring 10 is placed over the damper rod ,over the dust cover 9 which covers the Bump stopper at top (not shown) in conventional arrangement.
As depicted in FIG.2 shows the detailed view of Strut bottom mounting arrangement of conventional McPherson'strut arrangement.
As depicted in FIG. 3 shows invention of Rubber mounted strut bottom consists of Strut bottom bracket 4, which is connected to the Knuckle 7 by bolts. The Rubber bush 5 is provided between the bracket 4 and strut 2 with the extended bottom rod 18. The movement of the bottom rod 18 is arrested by lock nut 6 at bottom with washer (not shown). Washer is provide to avoid noise.
During the wheel travel, the load from the road is directly transferred to the strutl, through knuckle 7. It transfers the load to the strut which makes the strut 1 to slide against the damper rod through the rubber mounted bolted bracket 4. further it is restricted by the compression of the rubber bush 5,provides the cushioning effect. Compression is such that and also the higher stiffness of the rubber, it can absorb maximum portion of the load at the bottom portion of the strut, which is transferred to the damper 2 and spring 10.
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31 MAR 2009

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.