FORM 2
THE PATENT ACT 1970
[39 of 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See Section 10 and Rule 13]
TITLE OF THE INVENTION An Improved Bumper Of A Vehicle
APPLICANT
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
Atul Ronghe, Pratap Daphal,
Asmita Sathaye and Nilesh Damakle
AH are 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 particularly describes the invention and the manner in which it is performed.

FIELD OF INVENTION
The present invention relates to a bumper system of a vehicle, and more particularly, a lightweight bumper system which provides energy absorption at the time of the vehicle collision.
BACKGROUND OF INVENTION
Generally, a bumper is attached to either end of the vehicle to absorb impact at the time of the collision of the vehicle. The vehicle front end is very important regarding energy absorption in the event of crash collisions as it decides the safety of the commuter.
A conventional front structure of a passenger vehicle is shown in figure 1. The front structure consists of pair of longitudinal members, cross member and bumper. The bumper of the conventional front structure is mounted on the cross members. The cross member is attached to the longitudinal members of the vehicle. The bumper is designed for slow speed impacts such as parking maneuvers. The cross member is designed for impact speed higher that the speed used for bumper designs. The longitudinal members are designed for energy absorptions at very high speed. The longitudinal member and cross member are provided with a crush initiators to promote their deformations and thus absorb energy in the event of crash collisions of the vehicle.
The conventional vehicle front end structure is heavy and it is not an integrated front structure which makes it incompatible for oblique and non-centralized frontal impact of the vehicle. In the front bumper of conventional vehicle, it is not possible to optimize the performance depending on the application without increasing the overall weight of the front structure.

The present invention does not require a cross member for mounting of the bumper. The bumper can be mounted on the longitudinal members directly. Also the longitudinal members needs not have the crush initiators for promoting energy absorption. The present invention front end structure is lighter than the conventional bumper and it is an integrated front end structure of the vehicle.
OBJECTIVES OF THE INVENTION
The main object of the present invention is to provide an impact energy absorbing bumper of a vehicle.
Another object of the present invention is to provide a boltable and lightweight vehicle bumper.
Yet another object of the present invention is to provide a bumper in which plurality of foam of varying stiffness can be disposed between an outer skin and inner skin of the vehicle bumper.
SUMMARY OF THE INVENTION
The present invention relates to an energy absorbing bumper for a vehicle comprises of a fascia member in the form of an outer skin provided at outermost side of said vehicle to receive impact forces, a backing member in the form of a rear skin positioned rearwardly of said fascia member, said backing member having face surface and end surface, said face surface of the backing member is attached with said fascia member to form a hollow portion, said end surface of said backing member is attached to said vehicle's body by means of a fixture, atleast first impact energy absorber provided on said face surface of said backing member and atleast second impact energy absorber disposed within said hollow portion. The first energy absorber has higher impact resistance than the second energy absorber and the second energy absorber is obtained by injecting a liquid which fills up space

inside the hollow portion and gets attached to said outer skin, said rear skin and said first energy absorber by virtue of self adhesion during solidification from its liquid form.
According to another aspect of the present invention, said first and second impact energy absorbers are stiff foam and soft foam respectively.
Most preferably, said outer skin is attached on the periphery of said rear skin by means of an adhesive.
Preferably, said outer skin and rear skin are made from plastic material.
According to yet another aspect of the present invention, a plurality of foams of varying stiffness is disposed between said outer skin (6) and rear skin (7) as impact energy absorbers.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiment of the invention and, together with the description, explain the invention. In the drawings,
Fig. 1 is an exemplary diagram illustrating front end of a conventional passenger
vehicle;
Fig. 2 shows an exploded view of an improved bumper in accordance with the
present invention;
Fig. 3 is a perspective isometric and sectional view of the improved bumper in
accordance with the present invention; and
FIG. 4 is a perspective view of a passenger vehicle fitted with the improved bumper
in accordance with the present invention.

Description of reference numbers for the major component of the present invention in the drawings are mention below:

Reference Number Description
1 Longitudinal member
2 Boltable member
3 Conventional bumper
4 Cross member
5 Crush initiators at longitudinal member
6 Outer skin of an improved bumper
7 Rear skin of an improved bumper
8 soft foam
9 stiff foam
10 Improved bumper
DETAILED DESCRIPTION OF THE INVENTION
The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following

description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
Figure 1 shows a conventional front structure of a passenger vehicle. It consists of longitudinal members (1), boltable member (2), conventional bumper (3), and cross member (4). The longitudinal member (1) and cross member (4) are provided with crush initiators (5) to promote their deformations under the influence of external forces. The conventional bumper (3) is made up of plastic and foam. The cross member (4) and the longitudinal member (1) are made up of metallic element. The conventional bumper (3) is connected to bumper mounting cross member (4). The cross member (4) is connected to the boltable member (2) preferably by welding and the boltable member (2) is connected to longitudinal member (1). In the event of frontal impact the load path starts from the bumper (3) and passes to the longitudinal member (1) through the bumper mounting cross member (4) and the boltable member (2). The impact energy is absorbed by the crush initiators (5) of the front end structure primarily.
An exploded view of an improved bumper of the vehicle is shown in figure 2 in accordance with the present invention. The improved bumper comprises of outer skin (6), rear skin (7), soft foam (8) and stiff foam (9). The outer skin (6) and the rear skin (7) are preferably made up of plastic. The assembling process of the improved bumper is described herein. The rear skin (7) is held firmly on a fixture and stiff foam (9) is attached on front face of the rear skin (7) with adhesive. The outer skin (6) is attached on the periphery of the rear skin (7) with adhesive forming an envelope. The soft foam in liquid form is injected inside the envelope formed by the adhesion of outer skin (6) and rear skin (7). The injected liquid solidifies to form solid soft foam (8).

An isometric and cross sectional views of the improved bumper are shown in the figure 3. The cross sectional view for a section (A-A) taken at the center of the bumper shows the packaging of soft foam (8) and stiff foam (9) inside the envelope enclosed by the adhesion of outer skin (6) and rear skin (7). The soft foam (8) in the form of liquid fills up the space inside the envelope and gets glued to the outer skin (6), rear skin (7) and the stiff foam (9) by virtue of self adhesion during solidification from its liquid form. The stiff foam (9) is attached to the rear skin (7) with adhesive.
Figure 04 shows isometric and side of the vehicle fitted with the improved bumper (10). The improved bumper (10) represents the front of the vehicle and performs the function of energy absorption during frontal impact of the vehicle.
In event of collision of the passenger vehicle, the bumper element will absorb all the required energy and ensure safety of the passenger. The soft foam is provided for energy absorption in the slow speed impacts wherein the stiff foam is used for energy absorption at high speed impact. However depending on the application, it is possible to introduce more foams of different stiffness in order to optimize the performance of the improved bumper.
Equivalents
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted

as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood

by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

WE CLAIM
1. An energy absorbing bumper for a vehicle comprising:
- a fascia member in the form of an outer skin (6) provided at outermost side of said vehicle to receive impact forces;
- a backing member in the form of a rear skin (7) positioned rearwardly of said fascia member; said backing member having face surface and end surface, said face surface of the backing member is attached with said fascia member to form a hollow portion, said end surface of said backing member is attached to said vehicle's body by means of a fixture;
- atleast first impact energy absorber (9) provided on said face surface of said backing member; and
- atleast second impact energy absorber (8) disposed within said hollow portion,
wherein said first energy absorber (9) has higher impact resistance than said second energy absorber (8) and wherein said second energy absorber (8) is obtained by injecting a liquid which fills up space inside said hollow portion and gets attached to said outer skin (6), said rear skin (7) and said first energy absorber (9) by virtue of self adhesion during solidification from its liquid form.
2. The energy absorbing bumper as claimed in claim 1, wherein said first impact energy absorber is stiff foam (9).
3. The energy absorbing bumper as claimed in claim 1, wherein said second impact energy absorber is soft foam (8).

4. The energy absorbing bumper as claimed in claim 1, wherein said outer skin (6) is attached on the periphery of said rear skin (7).
5. The energy absorbing bumper as claimed in any of the preceding claims, wherein said outer skin (6) and rear skin (7) are made from plastic material.
6. The energy absorbing bumper as claimed in any of the preceding claims, wherein said outer skin (6) is attached on periphery of said rear skin (7) by means of an adhesive.
7. The energy absorbing bumper as claimed in any of the preceding claims, wherein a plurality of foams of varying stiffness is disposed between said outer skin (6) and rear skin (7) as impact energy absorbers.