Stock material or miscellaneous articles – Structurally defined web or sheet – Including fastener for attaching to external surface
Reexamination Certificate
1998-10-28
2001-07-31
Waltkins, III, William P. (Department: 1772)
Stock material or miscellaneous articles
Structurally defined web or sheet
Including fastener for attaching to external surface
C428S099000, C428S132000, C428S133000, C428S139000, C428S140000, C428S166000, C428S178000, C428S223000, C428S457000, C428S220000, C264S523000, C264S241000, C264S259000, C264S264000, C264S269000, C264S271100, C264S274000, C264S275000, C264S279000, C220S560130, C220S592110, C220S529000
Reexamination Certificate
active
06268037
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a composite automobile component and the method of making that automobile component. More particularly, the present invention relates to a fuel tank which includes a shield to protect the fuel tank from heat generated from other engine components and a method of making the shielded fuel tank in situ while blow-molding the fuel tank in a mold. Even more particularly, the present invention relates to a shield attached to a blow-molded component so as to create a plurality of air gaps therebetween.
2. Description of the Related Art
In the past, fuel tanks have been made from metal, more particularly steel. Steel is relatively impervious to damage from many of the road hazards present, namely rocks, potholes, and the like. Also, steel will not deform or degrade in the presence of heat radiated from other components of the automobile, such as the exhaust system, which are located near the fuel tank.
More recently, however, it has become desirable to decrease the weight of vehicles to achieve better fuel efficiency, among other reasons. To decrease the weight, modifications have been made to many of the components of vehicles, including the fuel tank. The fuel tanks have begun to be made from lighter, less expensive materials, such as aluminum and plastics. However, a problem has arisen with the use of plastic in particular as the material from which the fuel tank is made.
A primary problem with substituting plastic for steel in the fuel tank is that, as mentioned earlier, there are components which radiate heat located near the fuel tank. Because plastic has a lower melting temperature than steel, the plastic fuel tank is more likely to degrade or rupture from the heat generated by the heat-radiating components, particularly the exhaust system, opposed to the steel fuel tank. As a result, it is necessary to provide some sort of shielding on or near the plastic fuel tank to reduce the heat transmitted to the fuel tank.
One option in preventing heat transmission is to install a heat shield between the exhaust system and the fuel tank. A variety of types of heat shields have been used in automobiles to shield components from heat. One example is found in the patent to Butler, U.S. Pat. No. 5,656,353. However, with the Butler shield as with others, the shield must be spaced from each of the heat-radiating component and the component the shield protects. In the context of the fuel tank and exhaust, the space limitations, such as requirements for clearance of the exhaust from the ground, prohibit the degree of spacing required by the Butler shield. A shield which is formed integrally with the fuel tank is, therefore, preferable.
An example of one attempt to provide a shield for a plastic fuel tank is disclosed in the patent to Stiles et al., U.S. Pat. No. 5,188,981. Stiles describes a structure which includes a number of layers. Most particularly, Stiles describes a fuel tank made of a thermoformable material and including a localized heat shield. However, in the Stiles reference, it is critical that the heat shield material and thermoformable material be selected such that the thermoformable material can penetrate into a portion of the heat shield material. This necessary characteristic limits the materials from which the heat shield and the fuel tank may be made.
The structures previously used do not allow for sufficient flexibility in the materials used to create the shield and are limited relative to their position with respect to the shielded and heat-generating components. Nor do these prior systems provide sufficient flexibility to permit their use as shields over more than a relatively limited area of a fuel tank which may be desirable to shield the fuel tanks from other road hazards, such as rocks, potholes, and the like. The present invention provides an alternative which more satisfactorily fulfills these highly desirable objectives.
An invention related to the present invention, entitled HEAT SHIELDS FOR BLOW-MOLDED COMPONENTS AND METHOD OF MAKING was filed in the U.S. Patent and Trademark Office on Oct. 19, 1998, and has been given Serial No. 09/175,398 now abandoned. The invention disclosed and claimed in that application may be modified to achieve a different result from the result garnered without the modifications disclosed and claimed in the present invention. The disclosure in the above-mentioned application is incorporated herein by reference.
SUMMARY OF THE INVENTION
The present invention relates to a composite automobile component. The automobile component includes a metal sheet and a blow-molded layer. The metal sheet includes protrusions extending away from a first broad surface of the metal sheet. The blow-molded layer is attached to the metal sheet by forming the blow-molded layer in situ in a surrounding relationship to the protrusions, thereby fixing the blow-molded layer to the metal sheet.
The metal sheet is configured such that the protrusions define regular polygonal shapes across the metal sheet. These shapes are plain areas on the metal sheet. In the blow-molding process, a plurality of air gaps are formed between the blow-molded layer and the metal sheet, each air gap being defined between each plain polygonal area on the metal sheet and a corresponding area on the blow-molded layer.
The plain polygonal areas may have a width of between about ⅜ to 5 inches. A preferred width is about one inch. Each plain polygonal area may share sides with adjacent plain polygonal areas, and these sides may be of equal length. One preferred plain polygonal area is hexagonal.
The protrusions may be formed by punching the metal sheet and the protrusions may be spaced from one another by about {fraction (3/16)} inch. The metal sheet may be at least about 0.0005 inch thick. The blow-molded layer may be made from a thermoplastic material.
Each plain polygonal area may be of a configuration and size selected to control the shrinkage of the blowmolded layer away from the first broad surface of the metal sheet to maintain the engagement of the blow-molded layer with the protrusions and to define a plurality of air gaps between the metal sheet and the blow-molded layer. The plain polygonal area is preferably large enough to allow the metal sheet to maintain the essentially same configuration as established in the mold while the thermoplastic material cools to form the blow-molded layer.
In the method of this invention, the metal sheet having the qualities mentioned above is releasably attached to an interior surface of a mold. A thermoplastic material is placed in the mold. The thermoplastic material is blowmolded to form a layer conforming to the shape of the mold and into contact with and in surrounding engagement to the protrusions. The plain polygonal areas and corresponding areas of the blow-molded layer define a plurality of air gaps once the thermoplastic material has fully retracted upon cooling. The protrusion on the metal sheet may be formed by punching.
Through the use of this combination of elements, an improved automobile component is shown.
REFERENCES:
patent: 5188981 (1993-02-01), Stiles et al.
patent: 5656353 (1997-08-01), Butler
patent: 5672405 (1997-09-01), Plunk, Jr. et al.
patent: 5846634 (1998-12-01), Werth et al.
patent: 6012493 (2000-01-01), Remke et al.
Butler Richard M.
Shah Hiten T.
Acoust-A-Fiber Research and Development Inc.
Foster Frank H.
Kremblas, Foster Phillips & Pollick
Waltkins, III William P.
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