Patent Application
20080054665
The advantages of this invention will become apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein:
Referring to
The horn section 18 of the lower frame rail 22 projects forwardly of the vertically extending portion of the upper frame rail member in a cantilevered manner to position the bumper (not shown) at the forward extremity of the vehicle and to start the management of crash energy by crushing rearwardly when encountering crash energy from an impact. After collapsing the horn sections 18, the impact forces encounter the structural joint 30 between the upper frame rail 12 and the lower frame rail 22. In situations where the horn sections 18 are angled downwardly from the structural joint 25, the horn sections 18 are subjected to a premature downward bending because of the offset eccentricity of the applied bending forces to the center of gravity of the horn section 18. In such situations, the horn sections 18 do not effectively manage the crash forces and subject the structural joint 25 to a greater exposure of crash energy.
To lower the center of gravity of the horn section 18 and remove the offset eccentricity of the downwardly angled horn section 18, the structural joint 30 is formed with a tubular reinforcement member 30 that is formed in a clamshell configuration with an inner member 32 configured to receive a nesting outer member 33. Welded together, the inner and outer members 32, 33 form a tubular body portion 34 that includes a forwardly extending support arm 35 that is positioned beneath the horn section 18 immediately forwardly of the vertically extending portion 15 of the upper frame rail member 12. Preferably, the support arm 35 is welded to the horn section 18. The body portion 34 also forms a pocket 36 that receives the end of the vertically extending portion 15 of the upper frame rail member 12. The outer member 33 is preferably formed with a welding flange 37 that bends outwardly to mate against the upper flame rail member 12 and facilitate the welding therebetween.
The horn section 18 is formed in a pre-folded configuration to enhance the crushing of the horn member 18 when encountering crash forces. The pre-folded configuration is defined by the convoluted surface of the horn member 18 to alternatively increase and reduce the effective cross section of the horn member 18. The convolutions form valleys 41 that reduce the cross-section of the horn section 18 between the ridges 43 that increase the cross-section of the horn section 18. Accordingly, the horn section 18 will collapse uniformly at the valleys 41 and expand outwardly at the ridges 43 when crash energy from an impact is encountered by the horn sections 18.
Once the crash energy reaches the rearward portion of the horn sections 18, the support arm 35 of the reinforcement member 30 acts as a second cell to increase the effectiveness of the horn section 18 to manage crash forces. If necessary, the welding between the vertically extending portion 15 of the upper frame rail member 12 and the lower frame rail member 22 along with the reinforcement member 30, particularly the welding flange 37 of the outer member 33, can be designed to break away upon encountering a sufficient crash force and direct the flow of crash energy as desired along the flow paths corresponding to the upper and lower frame rail members 12, 22.
The tubular configuration of the reinforcement member 30 provides a crushable reinforcement for the horn section 18 of the lower frame rail member 22, which does not detract from the effective management of crash energy by the horn sections 18. In fact, the double cell configuration of the horn section 18 coupled with the support arm 35 of the reinforcement bracket 30 increases the effectiveness of crash energy management. Furthermore, the forwardly extending support arm 35 lowers the center of gravity of a downwardly angled horn section 18 to provide a substantially increase resistance to bending forces to allow the horn sections 18 to collapse as intended. Even though the reinforcement members 30 increase the bending resistance of the horn section, the crushable tubular configuration of the reinforcement members 30 do not detract from the desired crushing of the horn sections 18.
It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention.
For example, the preferred configuration of the reinforcement member 30 is a two-piece clamshell construction having an inner member 32 and an outer member 33 received within the inner member 32. The reinforcement member 30 could instead be a one-piece tubular member formed through a hydroform manufacturing process. In the alternative, the reinforcement member 30 could be formed with the inner member 32 incorporating a tubular support arm 35 with the outer member 33 received within the inner member 32 behind the support arm 35. Any of these configurations, as well as other embodiments, would provide a crushable reinforcement member 30 that would increase the bending capacity of the horn section 18 without departing from the crushability of the horn section and the associated efficient management of crash energy.
