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Pedestrian Protection bumper system Disclosure Number: IPCOM000126221D
Publication Date: 2005-Jul-08
Document File: 4 page(s) / 1M

Publishing Venue

The Prior Art Database


A bumper assembly comprises a cover and an undertray which are arranged and tuned to absorb energy at differing rates throughout an impact.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 54% of the total text.

Page 1 of 4

Pedestrian protection bumper system

It is described below a bumper system which enables to reduce injury to a pedestrian in case of the latter is hit by a vehicle.

The bumper system comprises a cover (Fig. 1) and an undertray (Figs.2 and 3) which are arranged and tuned to absorb energy at differing rates throughout the impact.



Vertical columns

Figure 1: Plot showing the variation in cover thickness.

Rib pattern

Fixings to Vertical columns on Cover features

Flap features

Fixings to Lower section of Cover to form box-section

Figure 2: Plot showing flap feature and rib pattern on the Undertray.

Disclosed anonymously

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Page 2 of 4

Cover vertical columns to Undertray

Figure 3: Plot showing some of the key features on Undertray.

The Cover and the undertray are advantageously assembled as shown in Figs. 4 and 5.

Flap features to control intrusions Cover to Undertray attachments that box- section

Lateral hoop reinforcement generated by box section

Undertray to Cover


 Section Offset fixings to equalise stiffness Figure 4: Section plot showing box section formed by Cover and Undertray.

Disclosed anonymously

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Page 3 of 4

Cover Column to Undertray fixing

Optimised stiffening ribs for load transfer to Subframe

Figure 5: Section plot showing the Undertray to Cover Column attachment.

It is described below how such a bumper system will react during an impact.

1st Phase of impact

Initially, the Top, middle and bottom region of the bumper have been tuned to absorb the Legform impact at the same rate and the axis of the Legform impactor remains vertical, thereby maximising the absorption of energy. The vertical columns on the Cover that tie the undertray to the middle section, are particularly important in controlling the energy absorption during this phase.

After the Legform has intruded a specific distance, the Bottom region (consisting of the Undertray and Cover components) starts to stiffen relative to the others, and thereby initiates a rotation in the Legform about the lateral axis.

The point at which the Legform starts to rotate is controlled by the following design features:

* The relative height of the Undertray to Legform Lower Tibia's centre of gravity.
* The box section formed by the overlay and offset of the Cover and Undertray through the critical region for Legform impact
* The optimised rib pattern on the Undertray
* The number, pitch and location of fixings between the Cover and Undertray

* Varying local thicknesses of components in this region
* The flap feature on the Undertray to assist in controlling Legform intrusion by providing additional stiffness and by limiting the Bumper Cover movement in the Bottom region.

Disclosed anonymously

[This page contains 3 pictures or other non-text objects]

Page 4 of 4

2nd Phase of impact

During the next phase of the impact, the Legform rotation is encouraged by the foll...