FORM - 2
THE PATENTS ACT, 1970
(39 OF 1970)
AND
THE PATENTS RULES, 2003
"COMPLETE SPECIFICATION"
(SEE SECTION 10; RULE 13)
"VEHICLE BONNET HINGE STRUCTURE FOR PEDESTRIAN IMPACT"
MAHINDRA & MAHINDRA LIMITED
AN INDIAN COMPANY,
R&D CENTER, AUTOMOTIVE SECTOR,
89, M.I.D.C, SATPUR,
NASHIK-422 007,
MAHARASHTRA, INDIA
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES AND ASCERTAINS THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF THE INVENTION:-
The present invention is related to vehicle body system. More particularly the present invention is related to bonnet hinge structure of an automotive vehicle for pedestrian safety.
BACKGROUND OF THE PRESENT INVENTION:-
In today's automotive field, human safety has become an important aspect in designing automotive systems. A variety of vehicle body hinges targeted to protect the pedestrian in case of impact are available in public domain with varying degree of success.
European patent No. EP.2106976 discloses a collapsible hood hinge. This hood hinge arrangement is made from one single piece of material, comprising a first portion to be fixed to the body of the passenger car, a second portion to be collapsible in a substantially vertical direction, and a third portion to be supported by the a-pillar of the passenger car for absorbing compressive forces, whereby the second portion, in case of said impact, will collapse and allow the hood and the hood hinge element to be downwardly displaced so as to reduce the force of the impact, and the third portion will deflect in conjunction with the collapsing movement of the second portion as well as restrain the hood from moving in the direction of the windscreen of the passenger car.
But this prior art hood hinge is of collapsible type. It does not absorb the energy. In case of head impact, it collapses thereby reducing the injury to the pedestrian.
French patent No. FR.2929210 (Renault SAS) describes bonnet structure for car, has pedestrian impact absorbing device with semi-rigid membrane formed of channels, which are connected to deformable pouches and variably co-operate with hinge based on speed of impact and deformation of bonnet.

The structure has a pedestrian impact absorbing device comprising a semi-rigid membrane that is formed of a set of channels filled with liquid e.g. water.
American patent application No. US.2009078487 describes mechanical absorption systems for an active bonnet hinge. In this invention bonnet assembly rises with the help of deployed mechanism. In this prior art document, actuator is used to raise the bonnet assembly making the system little complex and costly.
OBJECTIVES OF THE PRESENT INVENTION:-
The main objective of the present invention is to provide bonnet hinge structure of automotive vehicle for pedestrian protection in case of collision.
Another object of the present invention is to provide low cost solution to reduce the head injury criteria (HIC) while pedestrian head is collided with the hood.
Another objective of the present invention is to provide vehicle hood hinge structure for pedestrian protection wherein head impact energy is absorbed by the hinge by undergoing deformation.
STATEMENT OF THE INVENTION:-
Accordingly the invention provides a vehicle bonnet hinge structure for pedestrian impact with four bar mechanism comprises four arms/bracket, first arm /bracket having one end flat portion, with two holes at distant for fixing second arm/bracket and forth arm/bracket, in vertical plane and other end the flat portion, with one hole and a slot at distant, in horizontal plane; a third arm/bracket, at distant and parallel to the said first arm/bracket, fixed to the second arm and slid able supporting the fourth arm/bracket; the said first arm/bracket provided with an energy absorbing U-shaped formation below the one of the said holes for fixing the said fourth arm/bracket; and the said

third arm provided with a cut out for allowing free travel of the said fourth arm/bracket.
BRIEF DESCRIPTION OF THE FIGURES:-
Figure 1 shows the bonnet hinge assembly in accordance with the present invention.
Figure 2 shows view of bracket (1) which is designed to absorb impact energy during head impact as shown in figure 1.
Figure 3 shows side view of the bracket (1) and its cross section along A-A of the side view.
Figure 4 shows side view of the bracket (3) of the hinge as shown in figure 1 and its cross sectional view along B-B
DETAILED DESCRIPTION OF THE PRESENT INVENTION:-
Referring to Figure 1, hood hinge of a present invention is a four bar mechanism hinge. As shown in figures it has four arms (1, 2, 3 & 4). At the time of head impact, bracket (1) impacts with hard points of vehicle structure and behaves very rigid. In order to make it robust for pedestrian impact, energy absorber structure was provided in bracket (1) as shown in figure 2. At the time of impact it absorb considerable amount of impact energy and reduces the head injury. Fig:3 represents Bracket-1 and it's cross-section. Another feature is provided in bracket (3) in the form of cut outs of a particular profile as shown in figure 4. This cut-out allows bracket (2) more room for free travel. It further helps to reduce head impact criteria (HIC).
More particularly the vehicle bonnet hinge structure for pedestrian impact with four bar mechanism as shown in the figure 1 comprises four arms , first arm/bracket (1) having one end flat portion, with two holes at distant for fixing second arm/bracket (2) and forth arm (4) , in vertical plane and other

end the flat portion, with one hole and a slot at distant, in horizontal plane. A third arm/bracket , (3) at distant and parallel to the said first arm/bracket, fixed to the second arm/bracket and slid able supporting the fourth arm. The said first arm/bracket is provided with an energy absorbing U-shaped formation below the one of the said holes for fixing the said fourth arm/bracket and the said third arm/bracket provided with a cut out for allowing free travel of the said second arm/bracket.
The hood hinge of the present invention is not collapsible but it is deformable. Energy absorbers at the end of one bar is provided which in turn deforms on the impact of head. This bar comes into contact with body parts at the time of pedestrian head impact. This energy absorber absorbs sufficient amount of impact energy to reduce the HIC value.
In the event of pedestrian head collision on the hood top in the hood hinge area, the hood structure deflects and rests against solid structure below. Due to less gap available below hinge, the injury resulted through this are of severe/serious nature. To reduce these injuries a crushing feature is provided on the hinge bracket (1). During the pedestrian head impact, it deforms by taking the support of below structure. Thus it helps in absorbing the impact energy and reduces the pedestrian head injury levels.
THE ADVANTAGES OF THE PRESENT INVENTION ARE:-
• It is a simple and cost effective solution to reduce the HIC and protect the pedestrian from severe / serious injuries.
• The hood hinge of the present invention is easy to manufacture.

WE CLAIM:-
1. A vehicle bonnet hinge structure for pedestrian impact with four bar mechanism comprises four arms/bracket , first arm /bracket having one end flat portion, with two holes at distant for fixing second arm/bracket and forth arm/bracket, in vertical plane and other end the flat portion, with one hole and a slot at distant, in horizontal plane; a third arm/bracket, at distant and parallel to the said first arm/bracket, fixed to the second arm and slid able supporting the fourth arm/bracket; the said first arm/bracket provided with an energy absorbing U-shaped formation below the one of the said holes for fixing the said fourth arm/bracket; and the said third arm provided with a cut out for allowing free travel of the said fourth arm/bracket.