Vehicle bonnets

Abstract: A vehicle bonnet assembly includes a bonnet (30) hinged to the vehicle body adjacent a leading edge (31) and having releasable catch means (47) adjacent a trailing edge (41), the bonnet (30) being hinged to the vehicle body in a manner which will permit rearward movement of the bonnet (30) when an impact is applied to the leading edge (31) thereof, a lifting mechanism (40, 42) being provided to lift the trailing edge (41) of the bonnet (30) in response to rearward movement of the bonnet (30).

Description: The present invention relates to vehicle bonnets and in particular bonnets for motor cars. In modern motor car design, for visibility, aerodynamic and styling reasons, it is desirable that the bonnet line is kept as low as possible. As a result, there is generally very little clearance between the bonnet and the engine bay contents of the motor car. Consequently, the bonnet will provide very little cushioning effect when impacted by a pedestrian during an accident. It has been proposed to permit rearward movement of the bonnet when an impact load is applied thereto, means being provided whereby said rearward movement will lift the bonnet increasing the clearance between the bonnet and the engine bay contents and improving the cushioning effect. Hitherto this has been achieved by the use of suitable hinge mechanisms, as disclosed in DE-A-2711339 and JP-A-58211975. However, as such hinge mechanisms must permit normal opening and closing of the bonnet to provide access to the engine bay the hinge mechanisms used hitherto have, of necessity, been of complex design. Furthermore, with the arrangement disclosed in DE-A-2711339, the front edge of the bonnet must extend beyond the radiator grille, otherwise the pedestrian will impact the radiator grille and will be catapulted onto the bonnet without displacing the bonnet rearwardly. This places restraints on the design of the vehicle. With the invention covered by the present application, the bonnet will be moved rearwardly whether the pedestrian impacts the modular front end assembly or the leading edge of the bonnet. There will consequently be no restraints on the design of the vehicle in this respect. The system covered by the present application will also be effective in cushioning impacts with small children or in circumstances where the pedestrian is impacted by the front end of the assembly rather than the leading edge of the bonnet. The present invention provides a bonnet assembly which will provide pedestrian protection and which utilises simple hinge mechanisms of conventional design. According to one aspect of the present invention, a vehicle bonnet assembly includes a bonnet, said bonnet being hinged adjacent its leading edge to a modular front end assembly of the vehicle for pivotal movement about a first transverse axis of the vehicle, characterised in that the front end assembly is hinged to the vehicle for pivotal movement about a second transverse axis of the vehicle, the first transverse axis being spaced above the second transverse axis, so that the front end assembly is capable of pivoting rearwardly in response to an impact load being applied to the leading edge of the bonnet, pivoting of the front end assembly causing the bonnet to move rearwardly, means being provided adjacent the trailing edge of the bonnet to cause the trailing edge of the bonnet to move upwardly upon rearward movement of the bonnet. In accordance with the present invention, upon impact with a pedestrian, the vehicle bonnet is lifted to provide a clearance, so that the bonnet may deform to cushion the impact. The invention is now described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a sectional diagramatic view of a bonnet assembly in accordance with the present invention; and Figure 2 is a perspective view of a detail of the bonnet assembly illustrated in Figure 1. In the bonnet assembly illustrated in Figures 1 and 2, the bonnet 30 is hinged at its leading edge 31 to a modular front end assembly 32. The front end assembly 32 is mounted on a front longitudinal cross beam 33 of the vehicle structure, by means of a hinge 34, so that upon collision with a pedestrian, the front end assembly 32 is capable of pivoting rearwardly into the engine compartment. Shear pins 35 are provided to hold the front end assembly 32 in position until the load applied thereto by impact with a pedestrian exceeds a predetermined magnitude. Alternatively, torque limiting means, for example a torque loaded friction joint or structural failure joint may be associated with the hinge 34, for this purpose. In addition to acting as a platform for the bonnet hinge, the front end assembly 32 may also house the headlamps and cooling pack of the vehicle. A pair of rollers 40 are mounted one on either side of the bonnet 30 adjacent its trailing edge 41. Tracks 42 are attached to the inside surface of the inner wings 43 for engagement by the rollers 40. The tracks 42 define upper and lower grooves 44 and 45 in which the rollers 40 will locate when they engage the tracks 42. The tracks 42 are curved upwardly from the leading to the trailing end thereof. The upper groove 44 adjacent the leading end 46 of each of the tracks 40 is cut away so that the roller 40 associated therewith, which will normally be located adjacent the leading end 46, may be moved into or out of this portion of the track 42 to permit opening and closing of the bonnet 30. Releasable detent means 47 take the place of the upper groove 44 adjacent the leading end 46 of track 42 so that when the bonnet 30 is in the closed position they will overlie the rollers 40. If the vehicle is in collision with a pedestrian, impact of the leading edge of bonnet 30 will cause the shear pins 35 to shear, so that the front end assembly 32 will pivot rearwardly about hinge 34, into the engine compartment. The rearward movement of the front end assembly 32 will cause the bonnet 30 to move rearwardly and the rollers 40 will ride up the tracks 42, causing the trailing edge 41 of the bonnet 30 to lift, thus increasing the clearance beneath the bonnet 30 and improving its cushioning effect.

Claims: A vehicle bonnet assembly including a bonnet (30), the bonnet (30) being hinged adjacent its leading edge (31) to a modular front end assembly (32) of the vehicle for pivotal movement about a first transverse axis of the vehicle, characterised in that the front end assembly (32) is hinged to the vehicle for pivotal movement about a second transverse axis of the vehicle, first transverse axis being spaced above the second transverse axis, so that the front end assembly (32) is capable of pivoting rearwardly in response to an impact load being applied to the leading edge (31) of the bonnet (30), pivoting of the front end assembly (32) causing the bonnet (30) to move rearwardly, means (40, 42) being provided adjacent the trailing edge (41) of the bonnet (30) to cause the trailing edge (41) of the bonnet (30) to move upwardly upon rearward movement of the bonnet (30). A vehicle bonnet assembly according to Claim 1 characterised in that shear pins (35) are provided between the front end assembly (32) and a structural element of the vehicle to prevent rearward pivoting of the front end assembly (32) until the impact load applied to the leading edge (31) of the bonnet (30) exceeds a predetermined value. A vehicle bonnet assembly according to Claim 1 characterised in that torque limiting means are provided on the hinge connection between the front end assembly (32) and the vehicle, to prevent rearward pivoting of the front end assembly (32) until the impact load applied to the leading edge (31) of the bonnet (30) exceeds a predetermined value. A vehicle bonnet assembly according to any one of the preceding claims characterised in that a pair of rollers (40) are provided one on either side of the bonnet (30) adjacent the trailing edge (41) of the bonnet (30), tracks (42) being provided on the vehicle body for engagement by the rollers (40), the tracks (42) being inclined upwardly from the leading end (46) to the trailing end thereof. A vehicle bonnet assembly according to Claim 4 characterised in that catch mechanisms (47) are provided adjacent the leading ends (46) of the tracks (42) for engagement of the rollers (40), when the bonnet (30) is in its normally closed position, means being provided to release the catch mechanisms (47) to permit the bonnet (30) to be pivoted to an open position.

Inventors: CADY JOHN BILLINGTON, FISHER STEPHEN ANDREW, HOWARD MARK SHANE, LLOYD ROBERT CHARLES WILLIAM, THOMAS ALAN VAUGHAN, CADY, JOHN BILLINGTON, FISHER, STEPHEN ANDREW, HOWARD, MARK SHANE, LLOYD, ROBERT CHARLES WILLIAM, THOMAS, ALAN VAUGHAN
Applicants: JAGUAR CARS, JAGUAR CARS LIMITED
Application year: 1992
Main classification: B62D25
IPC codes: B60R21, E05D11