Tubular beam with single center leg

Abstract

A reinforcement beam for a vehicle bumper system comprises a single sheet deformed to define first and second tubes sharing a common single center wall. A channel rib is formed on each tubes and a crevice rib over the center leg forms a third rib. Edges of the sheet are deformed to a radius so that their surface consistently engages an associated radiused corner formed on ends of the center leg, which facilitates consistent abutting line engagement of material surfaces, and thus facilitates consistent welding. In a preferred beam, front wall sections of each tube are coplanar and form a face of the beam, with each channel rib and crevice rib providing added stiffness to the beam, and yet nothing extends forward of the coplanar front wall sections. Related apparatus and methods are also disclosed.

Description

[0001]This application claims benefit under 35 USC section 119(e) of provisional application Ser. No. 61 / 385,680, filed Sep. 23, 2010, entitled TUBULAR BEAM WITH SINGLE CENTER LEG, the entire contents of which are incorporated herein by reference.BACKGROUND[0002]The present invention relates to bumper reinforcement beams used in vehicle bumper systems, where the beam is tubular and has a single (mono) center leg. The present invention also relates to roll forming apparatus and methods of forming said beams. However, the present invention is not believed to be limited to only bumper reinforcement beams for vehicles.[0003]Modern vehicle bumper systems typically include a reinforcement beam designed for strength and impact characteristics in order to meet government and insurance industry standards for particular vehicles, but also designed to minimize overall vehicle weight, to maximize strength-to-weight ratios, to fit within confined vehicle package spaces, and to satisfy vehicle ae...

AI Technical Summary

Benefits of technology

[0009]In another aspect of the present invention, an apparatus includes a roll former including roll form stations with rollers for forming the sheet into the continuous beam with the four exterior walls and the common center leg, the roll former including a welding station with a welder and a weld box fixture, the welder generating an upwardly-angled laser beam for welding the continuous beam to permanently fix the cross section and being positioned under the continuous beam at a location upstream or downstream from the weld box fixture so that the laser beam welds within a down-facing crevice formed by one of the radiused edges abutting one of the radiused ends. By this arrangement, the welder welds the continuous beam from a position under the continuous beam yet is positioned away from falling debris.

Problems solved by technology

Further, many of the desired features above are conflicting, such that it is not clear how to improve a particular bumper reinforcement beam, or how to improve the roll forming process for making the beam.

For example, a heavier beam may be stronger, but would cause an unacceptable increase in vehicle weight.

High strength materials may be preferred, but they are expensive, difficult to form, and cause high wear on tooling.

However, this can require extra roll forming steps and stations as well as additional tooling, hardware and software controls, each of which increase capital investment and make the roll forming process more complex.

However, welders take up space along the roll form apparatus, especially where the welders are positioned at different stations along a length of a roll form apparatus, thus increasing floor space requirements considerably, as well as capital investment.

Nonetheless, it is difficult to weld in two opposing sides of a beam due to flying debris adversely affecting one or both of the welders.

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