FIELD OF THE INVENTION

The present invention relates generally to reinforcement of structures, and more particularly to reinforcement of vehicle structures using multiple reinforcing materials.

BACKGROUND OF THE INVENTION

In recent years, considerable attention has been directed toward improving vehicle performance in the event of collisions or other impacts. One particular aspect that has been addressed has been roof crush resistance. An object of such efforts has been to increase the loads that a vehicle roof is able to withstand (e.g., during a rollover accident) and to help thereby prevent intrusion of the roof into the passenger compartment. Efforts so far largely have been in the area of metal reinforcement, such as the increased use of steel structures for reinforcement. Unfortunately to perform an effective job of structural reinforcement relatively heavy structures are needed. This has an undesired effect of increasing vehicle weight, with an attendant decrease in fuel efficiency. Thus, there is a need for structural reinforcements that provide enough support to meet the need for roof crush resistance, and other structural reinforcement applications, while avoiding the detrimental effects of increasing the weight of the vehicle roof.

In various other vehicle locations, recent years have seen the increased use of structural reinforcements in which vehicle cavities are commonly fitted with structural reinforcements that aid in controlling deformation from an impact. For some applications, it has become popular in recent years to employ a carrier structure in combination with an expandable material as part of the reinforcement. See e.g., U.S. Pat. Nos. 6,932,421; 6,921,130; 6,920,693; 6,890,021; and 6,467,834 all incorporated by reference. Typically, these carrier structures are made solely of molded polymeric materials. Some are made solely of metallic materials. As has been the case for a wide number of applications of these structures, the size and geometry of the structure may be related to the extent of load bearing that is required for the application. Often, this has been addressed by simply increasing the amount of material used for the carrier (and thus the part weight) in response to the increased need for impact resistance. Attention to controlling multiple modes of deformation within a single carrier is often only incidental, if at all.

The reinforcement and support of vehicle roof structures provides a further particular challenge, especially in view of the cavity volumes in which reinforcement of the above type is possible. By increasing the amount of material used for the carrier, it may be difficult to employ a reinforcement that is large enough to provide the requisite support but small enough to fit within the confines of certain vehicle cavities, including pillars and door sills. In addition, many new vehicle designs, particularly those related to compact vehicles, require stronger reinforcements in even smaller cavities. Traditional reinforcement structures may not be suitable, as cavity size requirements often limit the ability to add more material to the reinforcements for strength increase.

Thus, there remains a need for alternative techniques that allow for the ability to improve the support capability of a carrier while avoiding the addition of substantial weight and further avoiding the expense and time associated with additional raw materials and additional processing time. There also remains a need for a structural reinforcement that can be made in a relatively low profile shape so that it can be employed with success in smaller cavities.

SUMMARY OF THE INVENTION

The present invention meets one or more of the above needs by the improved devices and methods described herein.

In one aspect, the present invention pertains to a structural reinforcement comprising a base portion, an expandable material and a localized reinforcement. The base portion may be an elongated base reinforcing portion having a longitudinal axis. The expandable material may be an expandable polymeric material at least partially associated with the base reinforcing portion. The localized reinforcement may be a localized reinforcement aligned generally parallel with the longitudinal axis and located within a contemplated impact deformation region of the structural reinforcement. The localized reinforcement may further be made of a material that is dissimilar from and has a higher tensile strength than the material of the base reinforcing portion so that upon impact in the impact deformation region the severity of deformation is substantially reduced as compared to a part without the localized reinforcement.

This aspect may be further characterized by one or any combination of the following features. The base reinforcing portion and the expandable polymeric material may be integrally formed of the same material. The localized reinforcement may include a fastening means that fastens the localized reinforcement to a vehicle structure or to the base reinforcing portion. The fastening means may attach to any mounting bracket, a seat belt mechanism or retractor, a pull handle bracket, a roof rack, a mirror bracket, a sunroof bracket, a bumper bracket, a hinge component, a chassis mount bracket, an engine bracket, a suspension component or a radiator bracket. The localized reinforcement may be made of a metallic material selected from steel, aluminum, titanium, nickel, magnesium, an alloy, a transition metal or any combination thereof. The localized reinforcement may be substantially completely covered by the base reinforcing portion, the expandable material, or both. The base reinforcing portion may include a curved first surface that is in contact with a curved localized reinforcement. The localized reinforcement may be a composite material. The localized reinforcement may have an outer surface and at least a portion of the outer surface may be in contact with the expandable material after expansion.

In a further aspect, the present invention contemplates a structural reinforcement comprising a base reinforcing portion having one or more extensions, an expandable polymeric material adjacent to the one or more extensions and a localized reinforcement. The base reinforcing portion may be elongated and may include a curved first surface and a longitudinal axis. The expandable material may be at least partially associated with the base reinforcing portion and the one or more extensions may cause the expandable material to expand vertically first and horizontally only after the expandable material extends beyond the height of the one or more extensions. The localized reinforcement may be aligned generally parallel with the longitudinal axis of the base portion and may be located within a contemplated impact deformation region of the structural reinforcement. The localized reinforcement may further be in contact with the curved first surface of the base reinforcing portion and may be made of a material that is dissimilar from the material of the base reinforcing portion.

This aspect may be further characterized by one or any combination of the following features. The expandable material may have a ductility ratio of about 2.5. The localized reinforcement may have a generally curved or U-shaped profile. The base reinforcing portion may be a metal part, a composite part, a polymeric part, or any combination thereof. The ductility of the base reinforcing portion material may be less than the ductility of the localized reinforcement material. The localized reinforcement may have one or more visible exposed surfaces after expansion of the expandable material. The structural reinforcement may include a top portion, a middle portion, and a bottom portion so that the localized reinforcement is only in contact with the middle portion. The base reinforcing portion, the localized reinforcement, or both, may contain a mechanical interlocking means.

In yet another aspect, the present invention contemplates a structural reinforcement comprising: a base reinforcing portion including a curved first surface and one or more extensions; an expandable polymeric material at least partially associated with the base reinforcing portion, wherein the expandable polymeric material is located adjacent to the one or more extensions such that the one or more extensions cause the expandable material to expand vertically first and horizontally only after the expandable material extends beyond the height of the one or more extensions; a localized reinforcement having a generally curved or u-shaped profile and located within a contemplated impact deformation region of the structural reinforcement, wherein: at least a portion of the outer surface is visibly exposed and in contact with the expandable material after expansion; the localized reinforcement is made of a material that is dissimilar from the material of the base reinforcing portion; the localized reinforcement is in contact with the curved first surface of the base reinforcing portion; and the ductility of the base reinforcing portion material is less than the ductility of the localized reinforcement material; a fastening means that fastens the localized reinforcement to a vehicle structure or to the base reinforcing portion.

