FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See Section 10; rule 13)
TITLE OF THE INVENTION
Novel wheel rim to prevent the tube & tyre slippage and method of
manufacturing thereof
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. Siddharth Gupta and Mr. Praful Bonde
all Indian nationals
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 describes the invention and the manner in which it is to be
performed.

Field of invention:
This invention relates to Novel wheel rim to prevent the tube and tyre slippage and method of manufacturing thereof more particularly to the modification done on the surface of bead seating periphery of metallic rim resulting in prevention of the slippage of the tyre over the rim when the automobile is subjected to severe braking and acceleration.
Background of invention:
The surface modification on the bead seating periphery of metallic rim is proposed in order to prevent the relative motion between the tyre and the metallic rim. Sudden braking and acceleration can produce slippage between tyre and wheel rim, which in turn results in cutting of the tube (for tube type tyres) eventually leading to the bursting of the tyres. In case of tubeless tyres the slippage of the tyre on the rim causes tyre imbalance and tyre stiffness variation
Presently when vehicles are subjected to the regular braking and acceleration, it is observed that the bursting of tyres occurs on regular basis. As a result of this failure, the newly assembled tyres even though in good condition, have to be replaced. On investigation of the failure, it was found that these incidents of tyre bursting were happening on the account of the slippage of the rubber tube on the surface of the metallic rim. During the assembly of the pneumatic tyres, soap solution is applied on to the metallic rim in order to have a smooth bead seating. In case of improper soaking of soap solution, if the freshly assembled pneumatic tyres are subjected to sudden braking or acceleration, there is a possibility of the tube or tyre slipping on the metallic rim. Hitherto, there is no provision available for the resolution of this problem.
In conventional method of manufacturing after cutting steel plate to the required size it is subjected to multistage forming. During the multistage forming, the steel sheet is formed as per the required shape and then welded in order to achieve the specified wheel rim diameter, rim width and the type of flange. Then the formed sheet is welded to make the outer periphery of the wheel rim. In order to make the inside portion of the wheel rim the steel

sheet is subjected to blanking and forming operation (refer fig 6 for detail). Subsequently it is welded to outer periphery of the wheel rim. Objects of invention
The main object of the invention is to obviate above mentioned drawbacks. Another object of the invention is to provide surface irregularities on flange of the wheel rim. Yet another object of the invention is to provide surface irregularities on bead seat of the wheel rim.
Summary of invention
Novel wheel rim to prevent the tube and/or tyre slippage comprising:
- wheel rim made of metal or alloy with a high pressure zone on flange and/or bead seating
area, low pressure zone along bend radius,
- surface modification on outer periphery of said wheel rim bead seating and said flange in order to prevent slippage of tube and tyre incase of tyre-tube arrangement or tubeless tyre over said rim,
- said surface modifications are of different types of designs and sizes of surface irregularities.
The surface modifications are in the form of annular, linear, diamond, dimpled shapes.
The rubber of tyre being an elastic material grips the irregularities once the tyre is inflated owing to greater surface contact area..
The surface modification will also help in reducing the air leakage, in case of tubeless tyres, along the bead periphery because of better grip.
The bead radius in this arrangement is kept smooth.
The surface modifications can be used for rims with different bead angles with angular variation of the bead seat and flange of the rim.

Manufacturing process of the novel wheel rim to prevent the tube and/or tyre slippage comprising following steps:
- steel plate before farming is subjected to knurling process on the limited area namely flange and/or bead seating area
- said knurling process creates said surface modification having rough corrugated surfaces,
- said same knurling process can also be done at multistage forming station with knurling tool during rolling operation.
Brief description:
Figure 1 shows the perspective view of wheel rim.
Figure 2 shows the cross-sectional view of wheel rim and tyre at different inflation
conditions.
Figure 3 shows Tyre Bead Pressure Profile.
Figure 4 shows proposed surface modifications on bead seat and flange on wheel rims.
Figure 5 shows Various Surface irregularity forms.
Figure 6 shows Manufacturing Process of Prior Art
Figure 7 shows Manufacturing Process of Instant Invention
Detailed description
It is proposed to do a modification on the surface of the outer periphery of the metallic rim, in order to enhance the grip levels between the rim and the tyre thereby reducing the relative motion between the two. This invention will minimize the possibility of tube or tyre slippage on the rim even in case of improper soaking of soap solution (used for bead seating and unseating)-
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 Fig.3, the bead seating pressure profile clearly shows the pressure variation along the bead contact area .There is a high pressure zone on the flange and bead seating area whereas along the bend radius the pressure drops. The proposed surface modification in

Fig.4, on the outer periphery of the wheel rim bead seating and flange is in accordance with this invention.
Referring to Fig 4, the proposed surface modification (1) is done on the outer periphery of the wheel rim bead seating and flange in order to prevent the slippage of the tube and tyre over the metallic rim. The surface modification in this invention will include different types (designs) and sizes of surface irregularities (refer Fig 5.) which can be in the form of annular, linear, diamond, dimpled and all the other possible shapes. The rubber being an elastic material will grip the irregularities once the tyre is inflated. Because of the irregular surface on the outer periphery of bead seating, the tube and tyre will have a better grip over the metallic rim owing to greater surface contact area. The better grip due to the surface modification will also help in reducing the air leakage, in case of tubeless tyres, along the bead periphery. The bead radius in this arrangement is kept smooth as there is no pressure variation in this region.
Surface modification on wheel rim bead seating is provided in order to prevent the slippage of for different type of tyres (with tube and without tube) at different temperatures with different tyre pressures under different running conditions. These surface modifications provided on wheel rim bead seating prevents tyre slippage over wheel rim thereof which is used for tubes or tyres with different materials. Similar surface modifications can be provided over wheel rim made up of different materials such as alloy, non alloy etc.; different sizes & types (designs) for example annular, linear, diamond, checkered, dimpled, and all the other possible shapes of surface modifications. Such surface modifications can also be used for rims with different bead angles (angular variation of the bead seat and flange of the rim). The proposed solution is cost effective and simple in construction.
Unlike the conventional manufacturing process in the instant invention as shown in figure 7 the steel plate before forming is subjected to the knurling process on the limited area (edges) which after forming process will become bead and flange area. The knurling process is done to create the rough corrugated surfaces. The same knurling process can also be done at multistage forming station with knurling tool during rolling operation depending upon the manufacturing feasibility .Addition of knurling process, in the steel sheet (Intended for the outer periphery of the wheel rim) can be carried out before or after forming process. The manufacturing process of the instant invention prevents the tyre and tube slippage, is simple to manufacture and avoids tyre burst conditions due to slippage.

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.

We Claim
1. Novel wheel rim to prevent the tube and/or tyre slippage comprising:
- wheel rim made of metal or alloy with a high pressure zone on flange and/or bead seating
area, low pressure zone along bend radius,
- surface modification on outer periphery of said wheel rim bead seating and said flange in order to prevent slippage of tube and tyre incase of tyre-tube arrangement or tubeless tyre over said rim,
- said surface modifications are of different types of designs and sizes of surface irregularities.

2. The novel wheel rim to prevent the tube and tyre slippage as claimed in claim I, wherein said surface modifications are in the form of annular, linear, diamond, dimpled shapes.
3. The novel wheel rim to prevent the tube and tyre slippage as claimed in claim 1, wherein rubber of tyre being an elastic material grips the irregularities once the tyre is inflated owing to greater surface contact area..
4. The novel wheel rim to prevent the tube and tyre slippage as claimed in claim 1, wherein the surface modification will also help in reducing the air leakage, in case of tubeless tyres, along the bead periphery because of better grip.
5. The novel wheel rim to prevent the tube and tyre slippage as claimed in claim 1, wherein bead radius in this arrangement is kept smooth.
6. The novel wheel rim to prevent the tube and tyre slippage as claimed in claim 1, wherein said surface modifications can be used for rims with different bead angles with angular variation of the bead seat and flange of the rim.
7. Manufacturing process of the novel wheel rim to prevent the tube and/or tyre slippage comprising following steps:
- steel plate before forming is subjected to knurling process on the limited area namely flange
and/or bead seating area

- said knurling process creates said surface modification having rough corrugated surfaces,
- said same knurling process can also be done at multistage forming station with knurling tool during rolling operation.
8. Novel wheel rim to prevent the tube and/or tyre slippage and method of manufacturing thereof as herein described with reference to accompanying drawings.