FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
CRASH BULB
Inventors: (a) ASLAM ADAM and (b) DESHPANDE SANJAY PRABHAKAR
Applicant: MAHINDRA & MAHINDRA LTD.
an Indiann Company
of R&D Centre, Automotive Division, 89, M.I.D.C, Satpur, Nashik -422007, Maharashtra, India
The following specification particularly describes the invention and the manner in
which it is to be performed.

Field of the Invention
This invention relates to the field of motor vehicle safety systems, more particularly, the present invention relates to the field of a collision protection apparatus that absorbs impact energy during a collision.
Background of the Invention
A conventional collision protection apparatus for a vehicle includes a bumper mounted on a front and rear ends of the vehicle. The bumper is a shield made of steel, aluminum, rubber, or plastic. The bumper absorbs the shock to prevent or reduce the damage to the vehicle, when a collision occurs, wherein a collision may be a high speed collision or a low speed collision. In case of a high speed collision the bumper gets deformed, thereby dissipating most of the energy that may otherwise damage essential elements of the vehicle. Further, as the bumper gets deformed the energy of the collision gets dissipated and accordingly the shocks are prevented from reaching the occupants and causing injury to the occupants of the vehicle. Some bumpers also use energy absorbers or brackets and others make use of foam cushioning materials for achieving shock absorption.
The bumpers are designed to prevent or reduce the physical damage to the front and rear ends of the passenger motor vehicles in case of collisions. The bumpers are designed to protect a hood, a trunk, a grille, a fuel supply system, a chassis, an exhaust system and cooling systems of the vehicle. Further, the bumpers ensure safety of equipment such as parking lights, headlamps and tail lights of the vehicle, in case of collisions. Furthermore, the bumpers absorb and dissipate most

of the energy of the collision by getting deformed, thereby keeping the occupants of the vehicle safe by preventing the shock of the collision from reaching the occupants of the vehicle. More specifically, the bumpers ensure safety to the components and occupants of the vehicles, by using the method of reducing the G loads (Gravitational loads) applied to the components and the occupants by absorbing specific amounts of energy during a vehicle collision. In recent times, the bumpers are also designed to reduce the injury caused to pedestrians colliding with the vehicle during an accident. However, the bumpers are not efficient enough in absorbing and dissipating all the energy of a high impact collision and prevent damage to the chassis of the vehicle. Accordingly, auxiliary energy absorbing structural elements are used along with the bumper in order to enhance the effectiveness of the collision protection systems and minimize the damage to the chassis of the vehicle. To meet the energy absorption needs, numerous auxiliary structural elements of metallic or non-metallic types have been suggested in the prior art.
A crash bulb is one such auxiliary energy absorbing structural element that is used along with the bumper element of the vehicle, the crash bulb is generally a structural element connected to or extending from a front end of the chassis of the vehicle and extending outwardly there from. In case of a high impact collision, the crash bulb disposed at the front end portion of the chassis localizes the damage to it self and can be replaced when damaged. However, the crash bulbs known in the prior art are disposed behind the bumper element of the vehicle.
United States Patent No. 7,344,008 discloses shock absorbing rectangular boxes. The shock absorbing rectangular boxes are deep drawn open boxes that are

disposed between a bumper beam and a vehicle body, said box having a bottom, a flange, and a plurality of side walls extending between said flange and said bottom, said flange extending along a plane which is substantially parallel to a plane along which said bottom extends. The side walls comprise one part adjacent the bottom and one part adjacent the flange and the two parts have different inclination so that a deformation guide is formed between them, said deformation guide extending along a plane substantially parallel to the planes of the flange and the bottom. The shock absorbing rectangular boxes are disposed between bumper beam and vehicle body and accordingly fail to minimize the damage to the vehicle bumper.
Further, United States Patent No. 6334638 discloses an attachment structure for a bumper beam. The attachment structure for a vehicle has a longitudinal axis comprising a side frame substantially parallel to the longitudinal axis of the vehicle, a pair of bumper stays attached to each end portion of the side frame and a bumper beam attached to the bumper stays, wherein each bumper stay comprises an impact absorbing member which is deformed to absorb impact when impact force is applied to the bumper beam and a holding member having rigidity larger than said impact absorbing member, and wherein said holding member is attached to said end portion of the side frame, the holding member is combined with the impact absorbing member while the bumper beam is attached to the impact absorbing member. However, the impact absorbing members are disposed beside the bumper element and as such the high energy of the impact first deforms the bumper beam and thereafter deforms the impact absorbing members. Accordingly, attachment structure for bumper beam fails to minimize the damage to the bumper beam.

United States Patent No. 6659535 discloses an impact damper. The impact damper acts as a connecting member between a bumper and a chassis of a motor vehicle for the purpose of damping the shock loading during a collision between this motor vehicle and an obstacle, predominantly through deformation work in a tube of the impact damper. The tube is connected to the chassis via a bracket and to the bumper via a bumper receptacle. The bumper receptacle, the bracket and the towing lug with the tube are connected to one another by a joining technique before they are connected to one another by a stamping operation. The impact damper is disposed between the bumper and the chassis and accordingly fails to minimize the damage to the vehicle bumper.
United States Patent Application No. 20040124645 discloses a deformable tubular crash box. The deformable tubular crash box is disposed between a bumper and a longitudinal beam of a motor vehicle, the axis of which is aligned perpendicularly to the longitudinal beam, characterized by the fact that the crash box is manufactured from steel, has an open cross section, base walls of the crash box being arranged facing the longitudinal beam and the bumper respectively, and side walls running perpendicular to the base walls create a space between the longitudinal beam and the bumper, and that the transition between the base and side walls has an arcuate shape. The deformable tubular crash box is disposed between a bumper and a longitudinal beam of the motor vehicle and accordingly, the deformable tubular crash box fails to minimize the damage to the bumper and longitudinal beam of the motor vehicle.
United States Patent Application No. 20050104392 discloses a bumper system for attachment to a vehicle. The bumper system includes at least one cross beam element and at least one deformation element arranged between the cross beam

element and the vehicle. The deformation element is configured to dissipate energy when the vehicle suffers impact on collision. The at least one deformation element is having at least one region that extends beyond a delimiting face of the cross beam element facing the vehicle. In this case also, the deformation element is disposed behind the cross beam and accordingly the bumper system fails to minimize the damage to the cross beam.
United States Patent No. 7,066,509 discloses an energy absorption impact system for vehicle bumpers. The energy absorption impact system for vehicle bumpers includes a mounting plate with a central opening there-through, and a generally box-shaped sheet metal crush member. The crush member has a top wall, a bottom wall and opposite sidewalls arranged in a generally frustro-pyramidal shape, defining a large end connected with a vehicle bumper, and a small end connected with the mounting plate about the central opening. Impact on the vehicle bumper in-elastically deforms the walls of the crush member toward the central opening in the mounting plate to absorb energy associated with the impact. The crush member behind the vehicle bumper and is disposed between the vehicle bumper and the mounting plate and accordingly fails to minimize the damage to the vehicle bumper.
Similarly, United States Patent No. 7,077,442 discloses a crash-box bumper mount. A bumper assembly disclosed therein has a cross beam formed with an outer vertical web and two horizontal sides extending inward from upper and lower edges of the web, and two vehicle frame members having support ends spaced inward from and vertically offset from a center of the cross-beam web. Respective crash boxes each formed as a horizontally extending tube have an outer end engaging the bumper cross beam and an inner end fixed to the frame members. The outer ends of the crash boxes are vertically offset from the

respective inner ends. The inner ends of the crash boxes bear outward generally only on the web and on one of the sides of the cross beam. The other of the sides of the cross beam is generally out of engagement with the crash boxes. However, the crash-box bumper mount disclosed therein is in-effective in minimizing the damage caused by a collision.
United States Patent No. 7407206 discloses a bumper structure for a motor vehicle and includes a cross member, and a crash box placed between the cross member and a longitudinal member, with the crash box having an attachment zone. Bolts extend through walls of the attachment zone and the longitudinal member for securing the crash box to the longitudinal member by forcing the attachment zone against the wall of the longitudinal member. The attachment zone undergoes locally an elastic or plastic deformation for realizing a self-centered disposition of the crash box in relation to the longitudinal member. The walls of the attachment zone and the longitudinal member extend at a tolerance distance before the crash box is secured to the longitudinal member. The crash box is placed between the cross member and a longitudinal member and therefore is in-efficient in absorbing energy of a high impact collision and minimizing the damage to the cross member of the motor vehicle.
United States Patent Application No. 20060237976 discloses a crush member for a vehicle having frame rails comprising a tube having a first end configured to be connected to the frame rails of the vehicle and a second end configured to be connected to a bumper. The tube has a constant thickness from the first end to the second end. The tube further has a taper along an axial direction from the first end to the second end, the tube having a larger cross section at the first end and a smaller cross section at the second end. The tube is configured to crush to absorb

impact energy upon an axial or near axial load. The tube of the crush member is also disposed between the frame rails of the vehicle and the bumper of the vehicle and accordingly fails to minimize the damage to the bumper of the vehicle.
United States Patent No. 7,360,811 a bumper for a motor vehicle. The bumper for the motor vehicle includes a cross member which is disposed transversely to a side rail of a motor vehicle frame, and a crash box which is connected between the side rails and the cross member. The crash box is configured in fold construction from a metal sheet and has a sidewall which exhibits a roof-shaped structure. The sidewall includes at least one wall section which is inclined in relation to the horizontal midsection transverse plane of the crash box. The crash box is connected between the side rails and the cross member and accordingly is inefficient in absorbing energy of a high impact collision and fails in preventing damage to the side rails and the cross member.
United States Patent No. 7,533,913 discloses a structure for a car body that is stated to reduce time and cost to repair a car body after a collision by localizing damage in low-speed collisions to a crash box mounted in a space between a front bumper and a side member and making the car body deform always in a predetermined mode in the collisions. A front structure for a car body may include a first connecting bracket supporting the left and right rear of a front bumper, a crash box joined to the rear of the first connecting bracket, a second connecting bracket joined to the rear of the crash box, and a front side member joined to the rear of the second connecting bracket. The crash box includes an inner member and an outer member, which are curved and separated from each other, so as to extend in the longitudinal direction of the vehicle and have a closed cross section. The inner member has a plurality of bead-shaped protrusions that

are formed across the inner member and longitudinally spaced from each other. However, the structure for a car body localizing damage in low-speed collisions is expensive and in-effective.
All the above mentioned disclosures disclose collision protection apparatuses that employ expensive and inefficient energy-absorbing and energy-dissipating means that make the systems costly to implement. Therefore, there is felt a need for a collision protection apparatus which can be designed and built using inexpensive mechanical elements, implement a predetermined crushing pattern, can reliably dissipate energy in case of both low and high impact collisions.
OBJECTS OF THE INVENTION
An object of the present invention to provide an impact energy absorbing collision protection structural device that is adapted to reduce damage to the chassis of an automobile by impact-energy of a collision.
Another object of the present invention to provide an impact energy absorbing collision protection structural device that can be designed and built using inexpensive mechanical elements.
Still another object of the present invention to provide an impact energy absorbing collision protection structural device that can absorb and dissipate energy during high impact collisions.

Still another object of the present invention to provide an impact energy absorbing collision protection structural device that is adapted to prevent damage to a bumper of the vehicle.
Still another object of the present invention is to provide an impact energy absorbing collision protection structural device that ensures occupant safety.
Another object of the present invention is to provide an impact energy absorbing collision protection structural device that is reliable and accurate.
Yet another object of the present invention is to provide an impact energy absorbing collision protection structural device that is easily replaceable.
SUMMARY OF THE INVENTION
A structural device for reducing damage to the chassis of an automobile by a collision is disclosed. The structural device includes a primary load path, a secondary load path and a mounting bracket. The primary load path includes a frangible hollow structure, wherein a free end of the frangible hollow structure has an inclined profile. The frangible hollow structure is adapted to collapse along the direction of impact to maximize energy dissipation during a collision. The secondary load path is disposed below the frangible hollow structure of the primary load path. The mounting bracket is adapted to removably mount the primary load path and the secondary load path to the chassis of the automobile.
Typically, the primary load path is formed by joining a pair of C-sectioned elongated members along longitudinal direction thereof.

Particularly, the C-sectioned elongated members are joined by welding.
Generally, the primary load path is welded to the mounting bracket.
More specifically, the primary load path includes a plurality of apertures adapted to facilitate crushing of the primary load path in a pre-determined pattern.
Preferably, the primary load path is of low carbon steel.
Further, the inclined profile at the free end of the frangible hollow structure is a chamfer cut.
Typically, the secondary load path includes a U-sectioned elongated member extending along longitudinal direction of the primary load path.
Further, the secondary load path includes a plurality of apertures adapted to facilitate crushing of the secondary load path in a pre-determined pattern.
Preferably, the secondary load path is of low carbon steel.
Generally, the secondary load path is welded to the mounting bracket and the primary load path.
Typically, the mounting bracket is a rectangular plate that includes a plurality of apertures for connecting the mounting bracket to the bumper mounting bracket,

wherein the mounting bracket is connected to a bumper mounting bracket disposed on the chassis of the automobile.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The collision sensing and protection system will now be described with reference to the accompanying drawing, in which:
Figure la-Figure lb illustrates different views of a prior art structural device that is integral with the chassis of a vehicle and is adapted to facilitate collision protection by absorbing impact energy during a collision;
Figure 2a-Figure 2b illustrates different views of another prior art structural device for facilitating collision protection by absorbing impact energy during a collision;
Figure 3 illustrates the impact energy absorbing structural device mounted on a front end of a chassis of a vehicle, in accordance with one embodiment of the present invention;
Figure 4 illustrates another view of the impact energy absorbing structural device mounted on the front end of the chassis of the vehicle;
Figure 5 illustrates another view of the impact energy absorbing structural device of Figure 3;

Figure 6 illustrates still another view of the impact energy absorbing structural device of Figure 3;
Figure 7 illustrates an enlarged isometric view of the impact energy absorbing collision protecting structural device of Figure 3;
Figure 8 illustrates an isometric view of a C-sectioned elongated member of the pair of C-sectioned elongated members joined together to form a primary load path of the impact energy absorbing collision protecting structural device of Figure 3;
Figure 9 illustrates an isometric view of another C-sectioned elongated member of the pair of C-sectioned elongated members joined together to form the primary load path of the impact energy absorbing collision protecting structural device of Figure 3;
Figure 10 illustrates an isometric view of the secondary load path disposed below the first frangible hollow structure of the impact energy absorbing collision protecting structural device of Figure 3;
Figure 11 illustrates an isometric view of a mounting bracket of the impact energy absorbing collision protecting structural device of Figure 3;
Figure 12a illustrates a front view of the impact energy absorbing collision protecting structural device of Figure 3 in an assembled configuration;

Figure 12b illustrates a side view of the impact energy absorbing collision protecting structural device of Figure 12a; and
Figure 12c illustrates a top view of the impact energy absorbing collision protecting structural device of Figure 12a.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS AND THE PREFERRED EMBODIMENT
Figure la of the accompanying drawings illustrate a prior art crash bulb 02 integral with the front end of the chassis of the vehicle and extending outwardly there-from. Figure lb of the accompanying drawing illustrates another view of the prior art crash bulb 02 of Figure la. The prior art crash bulb 02 as illustrated in the Figure la and Figure lb of the accompanying drawings also includes a secondary load bearing member 04 disposed below the front end of the chassis. However, the prior art crash bulb 02 illustrated in Figures la and lb, being integral with the chassis of the vehicle fail to prevent damage to the chassis of the vehicle.
Furthermore, Figures 2a and 2b illustrates another prior art crash bulb 06. The prior art crash bulb 06 illustrated in Figure 2a and 2b is also integral with the front end of the chassis of the vehicle and extending outwardly there-from. Further, the distal end face of the crash bulb includes a flat rim portion. The prior art crash bulb 06 also includes a secondary load bearing member 08 disposed below the front end portion thereof. The secondary load bearing member 08 is closed ended, wherein a flat plate closes the front end of the secondary load

bearing member 08. However, the prior art crash bulb 06 illustrated in Figures 2a and 2b is in-effective in absorbing impact energy during a collision.
A preferred embodiment will now be described in detail with reference to the accompanying drawings. The preferred embodiment does not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.
The present invention envisages an impact energy absorbing collision protecting structural device. The impact energy absorbing collision protecting structural device 100 is adapted to absorb and dissipate most of the high impact energy of a collision and thereby protect the occupants of the passenger cabin of the vehicle. Further, the impact energy absorbing collision protecting structural device 100 is adapted to minimize the damage to the chassis of an automobile. The impact absorbing device of the present invention comprises an auxiliary energy absorbing structural element that is disposed in-front of the bumper and is adapted to absorb energy of an impact collision and dissipate most of the energy before transferring the same to the bumper and the chassis of the vehicle, so as to minimize the damage to the bumper and chassis of the vehicle.
Referring to Figures 3-6 of the accompanying drawings, the impact energy absorbing collision protecting structural device 100 includes a combination of a primary load path 12 and a secondary load path 14. The primary load path is in the form of a frangible hollow structure 12 and the secondary load path is a frangible structural element 14. The frangible structural element 14 is adapted to support the frangible hollow structure 12. Each of the frangible hollow structure 12 and the frangible structural element 14 are mounted on a mounting bracket 10.

The mounting bracket 10 is connected to a bumper mounting bracket 16 disposed on a front portion of the chassis of the automobile. The mounting bracket 10 is removably mounted to the bumper mounting bracket 16 by means of fasteners such as nut and bolt arrangement. More specifically, the mounting bracket 10 is mounted to the bumper mounting bracket 16 that is disposed on a side member or a cross member of the chassis. However, the present invention is not limited to any particular method for mounting the mounting bracket 10 to the bumper mounting bracket 16. The bumper mounting bracket 16 is adapted to support a bumper such that the bumper is disposed behind the impact energy absorbing collision protecting structural device 100. In case of a collision, the impact of the collision first deforms the energy absorbing collision protecting structural device 100 and thereafter reaches the bumper and the chassis of the automobile, thereby minimizing damage to the bumper and the chassis of the automobile. More particularly, the impact of the collision first deforms the frangible hollow structure 12 and thereafter damages the frangible structural element 14.
Further, referring to Figures 3-6 of the accompanying drawings the impact energy absorbing collision protecting structural device 100 is removably attached to the front portion of the chassis of the automobile. Accordingly, when the impact energy absorbing collision protecting structural device 100 is damaged after a collision the same may be replaced. The mounting bracket 10 of the impact energy absorbing collision protecting structural device 100 is bolted to the bumper mounting bracket 16, which in-turn is secured to the main side members/long members or cross-member at the front portion of the chassis of the automobile. The frangible hollow structure 12 and the frangible structural element 14 are mounted on the mounting bracket 10 so as to extend outwardly from the mounting bracket 10. More particularly, the frangible hollow structure 12 and the

frangible structural element 14 are welded to the mounting bracket 10. Further, the frangible hollow structure 12 and the frangible structural element 14 are welded together to each other. Furthermore, bumper mounting bracket 16 is adapted to support the bumper of the automobile, such that the frangible hollow structure 12 and the frangible structural element 14 are disposed in front of the bumper and the frangible hollow structure 12 and the frangible structural element 14 are the first to face the impact of the collision, even before the bumper of the vehicle. Furthermore, referring to Figure 6 of the accompanying the frangible hollow structure 12 and the frangible structural element 14 of the impact energy absorbing collision protecting structural device 100 are adapted to support a bull-bar assembly 18.
The frangible hollow structure 12 as illustrated in Figure 7 of the accompanying drawings is formed by joining together a first C-sectioned elongated member 12a and a second C-sectioned elongated member 12 b. More specifically, the second C-sectioned elongated member 12b is welded to the first C-sectioned elongated member 12a in order to form the frangible hollow structure 12 of the primary load path.
Figure 8 of the accompanying drawings illustrates the first C-sectioned elongated member 12a and Figure 9 of the accompanying drawings illustrates the second C-sectioned elongated member 12b. The first C-sectioned elongated member 12a and the second C-sectioned elongated member 12b are generally made of sheet metal. Particularly, the first C-sectioned elongated member 12a, the second C-sectioned elongated member 12b and the frangible structural element 14 of the impact energy absorbing collision protecting structural device 100 is of low carbon steel material, with industrial designation as Fe410WC as per IS

5986:1992. However, the present invention is not limited to a particular material used for configuring the first C-sectioned elongated member 12a, the second C-sectioned elongated member 12b and the frangible structural element 14. Further, the present invention is not limited to a particular method for joining the first C-sectioned elongated member 12a to the second C-sectioned elongated member 12b.
In accordance with one embodiment of the present invention, the frangible hollow structure 12 of the primary load path is rectangular in cross-section. The frangible hollow structure 12 has an inclined profile at a free end thereof, wherein the inclined profile at the free-end of the frangible hollow structure 12 is a chamfered cut. The chamfered cut provided at free end of the frangible hollow structure 12 is extending inwardly from a top wall to a bottom wall of the first frangible hollow structure 12. The chamfered cut at the free end of the first frangible hollow structure 12 provides a piercing edge to the frangible hollow structure 12 that maximizes the energy dissipation during a collision of an object with the front portion of the vehicle. The collision first affects the frangible hollow structure 12 of the energy absorbing collision protecting structural device 100, thereby minimizing the harm to the vehicle on which the energy absorbing collision protecting structural device 100 is mounted.
Figure 10 of the accompanying drawings illustrates an isometric view of the frangible structural element 14 or the secondary load path 14. The frangible structural element 14, hereinafter referred to as a secondary load path 14 is disposed below the frangible hollow structure 12. The secondary load path 14 is adapted to provide support to the frangible hollow structure 12. The secondary load path 14 is generally a U-sectioned angle member disposed below the

frangible hollow structure 12, such that an operative bottom wall of the U-sectioned angle member, side walls of the U-sectioned angle member along with the bottom wall of frangible hollow structure 12 define an enclosure.
Further, the frangible hollow structure 12 and the secondary load path 14 includes a plurality of apertures configured thereon and adapted to facilitate crushing of the frangible hollow structure 12 of the primary load path and the secondary load path 14 in a pre-determined pattern.
Figure 11 illustrates an isometric view of a mounting bracket adapted to removably mount the primary load path and the secondary load path to the chassis of the automobile
Figure 12a-12c illustrates different views of the impact energy absorbing collision protecting structural device 100, with all elements thereof joined by welding.
TECHNICAL ADVANCEMENTS AND ECONOMIC SIGNIFICANCE
The technical advancements of the present invention include realization of an impact energy absorbing collision protection structural device that is adapted to reduce damage to the chassis of an automobile by impact-energy of a collision. The impact energy absorbing collision protection structural device can be designed and built using inexpensive mechanical elements. The impact energy absorbing collision protection structural device is adapted to absorb and dissipate energy during high impact collisions. The impact energy absorbing collision protection structural device exhibits enhanced rate of energy absorption. The

impact energy absorbing collision protection structural device is adapted to prevent damage to a bumper of the vehicle. Further, impact energy absorbing collision protection structural device is adapted to implement a pre-determined crushing pattern.
While considerable emphasis has been placed herein on the particular features of this invention, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We Claim:
1. A structural device for reducing damage to the chassis of an automobile, said structural device comprising:
■ a primary load path comprising a frangible hollow structure, wherein a free end of said frangible hollow structure has an inclined profile; said frangible hollow structure adapted to collapse along the direction of impact to maximize energy dissipation during a collision;
■ a secondary load path disposed below said frangible hollow structure; and
■ a mounting bracket adapted to removably mount said primary load path and said secondary load path to said chassis of said automobile.

2. The structural device as claimed in Claim 1, wherein said primary load path is formed by joining a pair of C-sectioned elongated members along longitudinal direction thereof.
3. The structural device as claimed in Claim 2, wherein said C-sectioned elongated members are joined by welding.
4. The structural device as claimed in Claim 1, wherein said primary load path is welded to said mounting bracket.

5. The structural device as claimed in Claim 1, wherein said primary load path comprises a plurality of apertures adapted to facilitate crushing of said primary load path in a pre-determined pattern.
6. The structural device as claimed in Claim I, wherein said primary load path is of low carbon steel.
7. The structural device as claimed in Claim 1, wherein said inclined profile at said free end of said frangible hollow structure is a chamfer cut.
8. The structural device as claimed in Claim 1, wherein said secondary load path comprises a U-sectioned elongated member extending along the longitudinal direction of said primary load path.
9. The structural device as claimed in Claim 1, wherein said secondary load path comprises a plurality of apertures adapted to facilitate crushing of said secondary load path in a pre-determined pattern.
10.The structural device as claimed in Claim 1, wherein said secondary load path is of low carbon steel.
11.The structural device as claimed in Claim 1, wherein said secondary load path is welded to said mounting bracket and said primary load path.
12.The structural device as claimed in Claim 1, wherein said mounting bracket is a rectangular plate that comprises a plurality of apertures for connecting said mounting bracket to said bumper mounting bracket, wherein said

mounting bracket is connected to said bumper mounting bracket disposed on said chassis of said automobile.