Patent Publication Number: US-2006006568-A1

Title: Method of making a grab handle

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a method of making an interior vehicle part, such as a grab handle.  
      2. Background Art  
      A prior method of making a grab handle involves positioning a metal bracket in a mold and injection molding plastic material around the bracket. Because the plastic material is typically rigid, the grab handle does not have a soft feel.  
      A prior method of making a vehicle arm rest involves injection molding a plastic substrate in a first mold and roto-casting a cover layer or skin in a second mold. A bracket may also be inserted into the first mold during formation of the substrate, and the substrate may be molded directly onto the bracket. Moreover, the skin may be painted after the roto-casting process to achieve a desired color and gloss. The substrate and skin are then positioned in a third mold such that the substrate and skin are spaced apart from each other. Expandable foam is then introduced between the substrate and skin.  
      Because multiple molds are involved in the above method, tooling costs are significant. Furthermore, because the components must be transferred from one mold to another, the method may be time consuming to implement.  
     SUMMARY OF THE INVENTION  
      Under the invention, a method of making an interior vehicle part for use with a motor vehicle is provided. The method includes the steps of spraying material proximate a surface of a mold portion of a mold to form a skin layer, the surface defining a mold cavity of the mold portion; positioning an insert proximate the mold cavity, the insert being configured for attachment to the vehicle; and introducing material into the mold cavity to form a foam layer that contacts the skin layer and the insert. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a top view of a grab handle according to the invention for use with a motor vehicle;  
       FIG. 2  is a cross-sectional view of the grab handle taken along line  2 - 2  of  FIG. 1 ;  
       FIG. 3  is a plan view of a mold for use in making the grab handle, wherein the mold is shown in an open position;  
       FIG. 4  is a cross-sectional view of the mold taken along line  4 - 4  of  FIG. 3  and showing application of in-mold coatings on the mold;  
       FIG. 5  is a cross-sectional view of the mold showing application of skin layers on the in-mold coatings;  
       FIG. 6  is a plan view of the mold showing an insert positioned on the mold;  
       FIG. 7  is a cross-sectional view of the mold showing application of foamable material on the skin layers; and  
       FIG. 8  is a cross-sectional view of the mold shown in a closed position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)  
       FIGS. 1 and 2  show an interior vehicle part, such as a grab handle  10 , according to the invention for use with a vehicle  11 . The grab handle  10  includes a foam substrate  12 , a skin layer  14  surrounding the substrate  12 , and a top coating  16  that covers the skin layer  14  and provides an exterior appearance surface. The grab handle  10  further includes an insert  18 , such as a bracket, for supporting the substrate  12  and for attaching the grab handle  10  to the vehicle  11 .  
      The substrate  12  may comprise any suitable foam material. For example, the substrate  12  may comprise an elastomer such as expanded polyurethane. Furthermore, the density of the substrate  12  is preferably, but not necessarily, in the range of 0.024 to 0.19 grams per cubic centimeter (g/cm 3 ). Advantageously, the substrate  12  may be configured to provide the grab handle  10  with a soft feel.  
      The substrate  12  may also be substantially thicker than the skin layer  14  and coating  16  combined. Alternatively, the substrate  12  may have any suitable thickness.  
      The skin layer  14  is adhered to the substrate  12  and coating  16 . Moreover, the skin layer  14  is configured to provide a resilient covering over the substrate  12  and may comprise any sufficiently dense material. For example, the skin layer  14  may be a solid layer that comprises an aromatic or aliphatic compound. As a more specific example, the skin layer  14  may be made of an elastomer such as polyurethane. Furthermore, the skin layer  14  may have any suitable thickness and density. For example, the skin layer  14  may have a thickness in the range of 0.3 to 10 millimeters (mm), and a density in the range of 0.15 to 1.5 g/cm 3 . In one embodiment of the invention, the skin layer  14  has a thickness in the range of 0.8 to 1.2 mm.  
      The coating  16  may be used to protect the skin layer  14  and/or to provide a decorative surface for the grab handle  10 . For example, the coating  16  may be used to inhibit sunlight or other ultraviolet light from reaching the skin layer  14 . As another example, the coating  16  may be used as a paint to provide a desired color or texture to the grab handle  10 . While the coating  16  may comprise any suitable material, in one embodiment of the invention the coating  16  is made of an aliphatic polyurethane composition. Furthermore, the coating  16  may have any suitable thickness, such as a thickness in the range of 0.5 to 1.5 mils.  
      Alternatively, the coating  16  may be omitted if not required for a particular application. For example, the skin layer  14  may be configured to provide a sufficiently durable and attractive surface such that the coating  16  is not needed.  
      The insert  18  may have any suitable configuration sufficient for attachment to the vehicle  11 . For example, the insert  18  may include attachment features, such as clips  20 , that are engageable with a panel of the vehicle. Furthermore, the insert  18  may be made of any suitable material such as plastic or metal.  
      Referring to  FIGS. 3-8 , a method of manufacturing the grab handle  10  will now be described.  FIG. 3  shows a mold  22  that may be used to make the grab handle  10 . The mold  22  includes first and second mold portions  23  and  24 , respectively, that may be separate or connected together. For example, the mold portions  23  and  24  may be pivotally connected together, such as with hinges  26 . The mold  22  is moveable between an open position in which the mold portions  23  and  24  are spaced apart from each other, as shown in  FIGS. 3-7 , and a closed position in which the mold portions  23  and  24  are disposed adjacent to and in contact with each other, as shown in  FIG. 8 . The first mold portion  23  includes a first mold surface  28  that defines a first mold cavity  30 , and the second mold portion  24  includes a second mold surface  32  that defines a second mold cavity  34 . In addition, the mold portions  23  and  24  may be heated to any suitable temperature if desired.  
      The method begins by spraying a mold release agent on each mold surface  28  and  32 . Next, referring to  FIG. 4 , a first in-mold coating  36  is sprayed on the first mold surface  28 , and a second in-mold coating  38  is sprayed on the second mold surface  32  using any suitable device, such as a robotic spray assembly  40  having one or more moveable spray heads  42 . While the coatings  36  and  38  may be made of any suitable material, in one embodiment, the coatings  36  and  38  comprise colored polyurethane. Furthermore, the coatings  36  and  38  cooperate to form coating  16  of the finished grab handle  10 .  
      Next, referring to  FIG. 5 , the method involves spraying skin layer forming material into the mold cavities  30  and  34  and onto the coatings  36  and  38  to form a first skin layer  44  that bonds to the first coating  36 , and a second skin layer  46  that bonds to the second coating  38 . The material may be any suitable substance and may be applied using any suitable device. For example, the material may include polyol and isocyanate, and the material may be sprayed with a robotic spray assembly  48  having one or more moveable spray heads  50 . As a result, the skin layers  44  and  46  may be formed of polyurethane. Furthermore, the skin layers  44  and  46  cooperate to form the skin layer  14  of the finished grab handle  10 .  
      As mentioned above, the coating  16  may be omitted from the grab handle  10 . In such a case, the skin layer forming material may be sprayed directly onto the mold surfaces  28  and  32 , or onto a mold release agent that is applied on the mold surfaces  28  and  32 , to form skin layers  44  and  46 .  
      The method then includes positioning insert  18  proximate one of the mold portions  23  and  24 . For example, each mold portion  23  and  24  may have a positioning feature or locator, such as a groove  51 , for receiving the insert  18 . In the embodiment shown in  FIG. 6 , the insert  18  is positioned on the first mold portion  23  such that the insert  18  extends above and adjacent to the first mold cavity  30 .  
      Next, referring to  FIG. 7 , the method involves introducing foam forming material into each mold cavity  30  and  34  and onto each skin layer  44  and  46  to form foam, which bonds to the skin layers  44  and  46 . The foam forming material may be any suitable substance and may be applied in any suitable manner. For example, the foam forming material may comprise polyol, isocyanate and a blowing agent such as water and/or a readily volatile organic substance. A specific example of a suitable blowing agent is DABCO® BL-17 available from Air Products and Chemicals, Inc. of Allentown Pa. Furthermore, the material may be sprayed with a robotic spray assembly  52  including one or more spray heads  54 , and the material may be allowed to free rise to achieve a desired density. With the material described above, the foam may be formed of expanded polyurethane.  
      Furthermore, the foam forming material may be applied on each skin layer  44  and  46  when the mold  22  is in the open position, such that a first foam layer  56  is formed on the first skin layer  44  and a second foam layer  58  is formed on the second skin layer  46 . With this approach, the mold  22  may then be moved to the closed position shown in  FIG. 8  to allow further expansion and/or bonding of the foam layers  56  and  58 , such that the foam layers  56  and  58  cooperate to form the substrate  12 . The substrate  12  also contacts and adheres to the insert  18 .  
      Alternatively, the foam forming material may be sprayed or otherwise injected into the mold cavities  30  and  34  when the mold  22  is in the closed position, thereby forming the substrate  12 . Under this approach, the mold  22  may be provided with one or more suitable injection passages (not shown) for introducing the material into the mold cavities  30  and  34 .  
      When the mold  22  is moved to the closed position, the skin layers  44  and  46  cooperate to form the skin layer  14 , and the coatings  36  and  38  cooperate to form the coating  16 . Furthermore, the skin layers  44  and  46  may bond to each other, and the coatings  36  and  38  may also bond to each other, when the mold  22  is in the closed position.  
      Under the invention, a single mold may be used to form the grab handle  10 , or other interior vehicle part. Thus, the method of the invention involves less tooling than prior art methods in which components are formed in separate molds.  
      Examples of other vehicle parts that may be made by the above method include arm rests and rollover bars.  
      Although separate spray assemblies  40 ,  48  and  52  are shown in the Figures, the spray assemblies  40 ,  48  and  52  may be provided as a single spray assembly that is configured to spray all of the above described materials. Furthermore, if the material to be sprayed includes multiple substances, the substances may be mixed at any suitable time. For example, the substances may be mixed upstream of, within, or downstream of associated spray heads.  
      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.