Patent Application
20070069548
1. Field of the Invention
The present invention relates to ribbed armrests and in particular to ribbed armrests made by over-molding.
2. Background Art
Interior trim panels for automobiles that are aesthetically and tactilely pleasing to the vehicle occupants are desirable. Such trim panels commonly have cushioned soft-touch aesthetic features. In particular, interior vehicle door panels often have localized cushioned areas in the armrest. Such localized softness may be provided by a flexible foam or elastomeric pad of varying thickness typically mounted to a rigid structural substrate, and surrounded by a relatively harder durometer cover sheet.
It is also known to form vehicle armrests by placing a nibbed back surface of a molded vinyl skin against a rigid structural substrate, and clamping the vinyl skin to the underside of the substrate with a closure plate. However, such known methods of manufacturing vehicle armrests typically require a series of multiple and separate molding and assembly steps which can add significant cost to each part produced. Moreover, in some of the prior art method for forming such nibbed armrests separate layers are adhered together with adhesives which are difficult to align precisely and again add cost to the process.
Accordingly, there is a need for improved processes for forming ribbed tactilely pleasing armrests.
The present invention overcomes one or more problems of the prior art by providing in one embodiment a ribbed armrest with a substrate section over-molded with a ribbed armrest section. Specifically, the substrate section is bonded to the ribbed armrest section with an over-molded bond as defined below. Both the ribbed armrest section and the substrate section of the ribbed armrest are made from resins. However, in many application the resin from which the substrate is formed is harder and more ridged than the resin from which the ribbed armrest section is formed. These differing characteristics stem from the differing functions for these components. The substrate provides support while the ribbed armrest section advantageously provides a soft cushioned feel.
In another embodiment of the invention, a method of making the ribbed armrest described above is provided. The method of this embodiment comprises positioning a first mold component and a second mold component to define a first mold cavity into which a first resin is subsequently introduced. Next, the first mold component and the second mold component are repositioned to form a second mold cavity. Characteristically, the second mold cavity has a ribbed mold section which is the inverse of a ribbed section of the armrest. A second resin into the second mold cavity to form an armrest layer. This armrest layer has a first section contacting at least a portion of the substrate and a second section having a plurality of ribs.
The following detailed description of the embodiments of the present invention can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Reference will now be made in detail to presently preferred compositions, embodiments and methods of the present invention, which constitute the best modes of practicing the invention presently known to the inventors. The figures are not necessarily to scale. However, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art to variously employ the present invention.
Except in the examples, or where otherwise expressly indicated, all numerical quantities in this description indicating amounts of material or conditions of reaction and/or use are to be understood as modified by the word “about” in describing the broadest scope of the invention. Practice within the numerical limits stated is generally preferred. Also, unless expressly stated to the contrary: percent, “parts of”, and ratio values are by weight; the term “polymer” includes “oligomer”, “copolymer”, “terpolymer”, and the like; the description of a group or class of materials as suitable or preferred for a given purpose in connection with the invention implies that mixtures of any two or more of the members of the group or class are equally suitable or preferred; description of constituents in chemical terms refers to the constituents at the time of addition to any combination specified in the description, and does not necessarily preclude chemical interactions among the constituents of a mixture once mixed; the first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and to normal grammatical variations of the initially defined abbreviation; and, unless expressly stated to the contrary, measurement of a property is determined by the same technique as previously or later referenced for the same property.
As used herein, “over-molding” refers to the injection molding process in which a first material is molded onto a second material. When properly performed, the first material forms a strong bond with the second material without the use of primers or adhesives.
As used herein, “over-molded bond” refers to the bond between a first material and a second material when the first material is over-molded onto the second material. It should be appreciated that the precise nature of the over-molded bond will depend on the type of materials bonded together. For example, if two plastics are bonded together the over-molded bond is typically cohesive in nature. If a resin is bonded to a somewhat porous material like clothe, the resin tends to fill openings in the clothe to form a type of interlocking bond.
With reference to
As set forth above, substrate section 16 comprises a resin. Typically, useful resins are thermoplastic resins. Particularly useful resins include, for example, thermoplastic polyurethanes, thermoplastic olefins, polyvinyl chloride, polypropylene, and combinations thereof. More specific examples of useful resins include homopolymers and copolymers of polyethylene, homopolymers and copolymers of polypropylene, polycarbonate, acrylonitrile butadiene styrene, mixed acrylonitrile butadiene styrene and polycarbonate, and combinations thereof. Similarly, armrest section 18 is also formed from a resin, and in particular, a thermoplastic resin. Again, useful resins include, for example, thermoplastic polyurethanes, thermoplastic olefins, polyvinyl chloride, polypropylene, and combinations thereof. More specific examples of useful resins include homopolymers and copolymers of polyethylene, homopolymers and copolymers of polypropylene, polycarbonate, acrylonitrile butadiene styrene, mixed acrylonitrile butadiene styrene and polycarbonate, and combinations thereof. Since armrest section 18 is usually softer than substrate section 16, armrest section 18 may also comprise elastomers. Examples of useful elastomers include thermoplastic elastomers, styrene-ethylene-butylene-styrene elastomers, blocked copolymer thermoplastic elastomers, polyolefin-based elastomers, foamed thermoplastic elastomers, and combinations thereof.
In another embodiment of the present invention, a method of forming the ribbed automobile door armrest set forth above is provided. The ribbed armrest is made by a molding process executed in a molding system. Injection molding is particularly useful for forming the ribbed armrests of the invention.
With reference to
In accordance with the method of this embodiment, the first resin forms substrate section 16. Accordingly, useful resins for the first resin are thermoplastic resins. Particularly useful resins include, for example, thermoplastic polyurethanes, thermoplastic olefins, polyvinyl chloride, polypropylene, and combinations thereof. More specific examples of useful resins include homopolymers and copolymers of polyethylene, homopolymers and copolymers of polypropylene, polycarbonate, acrylonitrile butadiene styrene, mixed acrylonitrile butadiene styrene and polycarbonate, and combinations thereof. Similarly, the second resin is used to form rubber armrest section 18. Again, useful resins for the second resin include, for example, thermoplastic polyurethanes, thermoplastic olefins, polyvinyl chloride, polypropylene, and combinations thereof. More specific examples of useful resins include homopolymers and copolymers of polyethylene, homopolymers and copolymers of polypropylene, polycarbonate, acrylonitrile butadiene styrene, mixed acrylonitrile butadiene styrene and polycarbonate, and combinations thereof. Since armrest section 18 is usually softer than substrate section 16, the second resin may also comprise elastomers. Examples of useful elastomers include thermoplastic elastomers, styrene-ethylene-butylene-styrene elastomers, blocked copolymer thermoplastic elastomers, polyolefin-based elastomers, foamed thermoplastic elastomers, and combinations thereof.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
