Abstract:
A resin molding includes an elongate body and a bent end that is continuous with the elongate body and is formed by a pressing operation. A back side of an intersecting portion of the elongate body and the bent end has reinforcing ribs formed by resin melted during the pressing operation. The resin molding is formed by extruding a melted resin, cutting the extruded resin into a predetermined length to form an intermediate product, heating and pressing an end of the intermediate product to bend the end, and introducing a melted resin onto the intermediate product during the pressing to form at least one reinforcing rib thereon to support the bent end.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     The present application is related to and incorporates by reference Japanese Patent Application No. 2003-392601, which was filed on Nov. 21, 2003.  
       BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates a generally to vehicle moldings, and specifically to a vehicle molding for installation on vehicle roofs.  
         [0003]     An automobile roof is typically fixed to the automobile body by welding both sides of a roof panel to a vehicle side panel. However, the welding creates an aesthetically unpleasing weld seam. In order to hide the seam, a roof molding such as that disclosed in Japanese Patent Application No. 2001-300953 is fixed on a groove defined by the welded roof and vehicle side panels.  
         [0004]      FIG. 5  illustrates an end of a roof molding  100 . The roof molding  100  has an elongate body  110  and a bent end  120 . The bent end  120  is formed continuously with the elongate body  110  and is bent at an angle from the elongate body  110 . The elongate body  110  has a finished side  111 , a base  112  and a lip portion  113 . The finished side  111  covers a groove (not shown) of the roof (not shown) and is visible on the exterior of the vehicle. The base  112  is formed on the back side of the finished side  111  and is inserted in the groove. The lip portion  113  is formed on the bottom of the base  112  in order to ensure the stability of the base  112  when inserted into the groove. A metal core is implanted in the base  112  to reinforce the base  112 .  
         [0005]      FIGS. 6A-6C  illustrate the manufacturing process of a roof molding such as that shown in  FIG. 5 . Initially, as shown in  FIG. 6A , a melted resin is extruded by an extruder (not shown), and then cut into predetermined lengths to produce an elongate intermediate product  130  with the finished side  111 , the base  112  and the lip portion  113 . The metal core  114 , which extends along the length of the intermediate product  130 , is implanted in the base  112  by a conventional insert molding method. Next, as shown in  FIG. 6B , a portion of the base  112  and the lip portion  113  corresponding to the groove formed between the roof interior and exterior panels is cut from an end portion  115  of the intermediate product  130  shown as the hatched portion. Finally, as shown in  FIG. 6C , the end portion  115  is heated and pressed by a core mold  141  and a cavity mold  142  to form a bent end  120 .  
         [0006]     In the roof molding manufactured as discussed above, the pressed end portion  115  is heated at a temperature that is lower than the melting point of the resin to prevent the surface of the roof molding from becoming roughened. Thus, the heating and pressing operation illustrated in  FIG. 6C  is carried out at a low temperature that creates a stretching tension at the surface of the bent end  120  and an internal shrinkage strain in the bent end  120 . Because of the shrinkage strain, the bent end  120  is gradually restored to its elongate shape once the heating and pressing operation is finished.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention overcomes the above mentioned limitations by providing a resin molding including an elongate body and a bent end. The bent end is continuous with the elongate body and is formed by a pressing operation. A back side of an intersecting portion of the elongate body and the bent end has reinforcing ribs formed by resin melted during the pressing operation. The reinforcing ribs have an associated thickness that is less than that of the bent end. The molding also has a fixing portion that protrudes from the back side of the elongate body that is for fixing the molding to a groove formed between a welded vehicle roof panel and vehicle side panels.  
         [0008]     The present invention also provides a method of manufacturing the above described molding. The method includes extruding a melted resin, cutting the extruded resin into sections each having a predetermined length to form an intermediate product, heating and pressing an end of the intermediate product to bend the end, and introducing a melted resin onto the intermediate product during the pressing to form at least one reinforcing rib thereon to support the bent end.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The accompanying figures, in which like reference numerals refer to identical or functionally similar elements throughout the separate views and which, together with the detailed description below, are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention.  
         [0010]      FIG. 1  is a top plan view showing a vehicle roof including a roof molding according to one embodiment of the present invention.  
         [0011]      FIG. 2  is a perspective view showing the back side of an end of the roof molding according to the embodiment of the present invention shown in  FIG. 1 .  
         [0012]      FIG. 3  is a side view showing the end of the roof molding shown in  FIG. 2 .  
         [0013]      FIGS. 4A-4C  illustrate a method of manufacturing a roof molding according to another embodiment of the present invention.  
         [0014]      FIG. 5  is a perspective view showing the end of a conventional roof molding.  
         [0015]      FIG. 6A-6C  illustrate a method of manufacturing the conventional roof molding shown in  FIG. 5 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]     Referring now to the drawings in which like reference numbers reference like parts, an automobile roof molding  1  and a method of manufacturing the roof molding will be described. Although the present invention will be discussed within the context of an automobile roof molding, it should be appreciated by one skilled in the art that the molding and method of manufacture are applicable to moldings for use in other vehicle locations as well as other equivalent applications.  
         [0017]     As shown in  FIG. 1 , roof moldings  1  are respectively affixed to a pair of long, thin grooves  12  formed on both sides of a roof  11  on an automobile  10 . Each of the grooves  12  is formed at a weld seam between a roof panel  13  and a side panel  14 . The roof moldings  1  (denoted in  FIG. 1  with oblique lines) are affixed to the grooves  12  in a manner described below to cover the grooves  12 .  
         [0018]      FIG. 2  shows the back side of an end of one of the roof moldings  1 , while  FIG. 3  shows a side view of the end of the roof molding  1  shown in  FIG. 2 . As shown in  FIG. 2  and  FIG. 3 , the roof molding  1  generally includes a body  2 , a bent end  3  and reinforcing ribs  4 , each of which will be described in detail below.  
         [0019]     The body  2  includes a finished portion  21 , a base  22  and a lip portion  23 . The finished portion  21  is made of a thermoplastic elastomer and is formed in an elongate manner with a predetermined thickness A. The thickness A of the finished portion  21  is preferably about 3.0 mm. The base  22  is made of a thermoplastic elastomer and extends transversely from a back side of the finished portion  21  generally along the center of the back side of the finished portion  21 . The base  22  is separated from the bent end  3  by a prescribed distance and is reinforced by a metal core  24  implanted therein. The metal core  24  is preferably straight and is preferably made of aluminum. The lip  23  is made of a thermoplastic elastomer and extends outwardly from a bottom side of the base  22  in a direction that is generally parallel with the finished portion  21 . The base  22  and the lip portion  23  are inserted in one of the grooves  12  to affix the roof molding  1  to the automobile  10 . The finished portion  21 , which covers the groove  12 , and the bent end  3 , which covers an end of the groove  12 , are visible from outside of the automobile  10 .  
         [0020]     Still referring to  FIGS. 2 and 3 , the bent end  3  is formed by heating and pressing the molding  1  at an end of the body portion  2 . The bent end  3  is formed continuously with the finished portion  21  by bending the finished portion  21 . The thickness of the bent end  3  is preferably about 2.5 mm.  
         [0021]     The reinforcing ribs  4  project outwardly from the back of a boundary  5  between the body  2  and the bent end  3 . The reinforcing ribs  4  are formed in the shape of a parallelogram with a predetermined thickness C that is preferably about 1.5 mm. According to a preferred embodiment, three reinforcing ribs  4  are affixed on the roof molding  1 , and adjacent ones of the reinforcing ribs  4  are separated by a predetermined distance.  
         [0022]     Referring now to  FIGS. 4A-4C , a method of manufacturing the roof molding  10  will now be described.  
         [0023]     As shown in  FIG. 4A , a melted resin is extruded from an extruder, and is then cut it into a predetermined length. Thus, an elongate intermediate product  6  is produced. The intermediate product  6  includes the finished portion  21 , the base  22  and the lip portion  23 . The metal core  24  is then implanted in the base  22  by insert molding the metal core  24  into the base  22  during the extrusion process.  
         [0024]     As shown in  FIG. 4B , a part of the base  22  and the lip portion  23  corresponding to the shape of the groove  12  and shown as the hatched portion is cut from an end portion  61  of the intermediate product  6 .  
         [0025]     Finally, referring to  FIG. 4C , the end portion  61  is heated from its back side and pressed by a mold that includes a core mold, or top mold portion  7 , and a cavity mold, or bottom mold portion  8 .  
         [0026]     In addition, the cavity mold  8  includes a rib mold  9  for forming the reinforcing ribs  4 . The pressed portion of the end portion  61  is heated to a temperature above the melting point of the elastomer material used to form the end portion  61  and is pressed by the core mold  7  to bend the pressed portion. The distance B (corresponding to the thickness of the bent end  3  shown in  FIG. 3 ) between the core mold  7  and the cavity mold  8  is narrower than the thickness A of the finished portion  21 . On the other hand, the thickness A of the finished portion  21  before the pressing process is constant as shown in  FIG. 4B . Therefore, when the core mold  7  and the cavity mold  8  are closed, the melted resin at the pressed portion that corresponds to the difference between the thicknesses A and B flows into the rib mold  9  as indicated by the arrows in  FIG. 4C . As a result, the bent end  3  is formed with the reinforcing ribs  4  due to the thickness B being narrower than the thickness A.  
         [0027]     The roof molding  1  resulting from the above manufacturing process includes the reinforcing ribs  4  at the back of the boundary  5  between the body  2  and the bent end  3 . Thus, the bent end  3  is strengthened. As represented by the arrows in  FIG. 3 , a contractile force acts on the inside of the bent end  3  to bias the bent end  3  back to its original straight shape. The contractile force also acts on the inside of the reinforcing ribs  4 . However, because the bent end  3  is secured by the reinforcing ribs  4 , deformation of the bent end  3  and recovery of the bent end  3  to its original straight shape is restricted.  
         [0028]     Because the reinforcing ribs  4  are formed as discussed above simultaneously with the bent end  3 , a sink mark around the boundary  5  and a joint mark at the finished portion  21  are not formed. Furthermore, because the bent end  3  and the reinforcing ribs  4  are formed by the same pressing process, the manufacturing method is simplified. Moreover, another process for forming the reinforcing ribs  4  is not required, and an increase in manufacturing complexity and in production costs is avoided.  
         [0029]     Furthermore, the thickness C of the reinforcing ribs  4  is not more than two thirds of the thickness B of the bent end  3 . Therefore, the restraint of sink marks is promoted. Moreover, because the pressed portion is heated from its backside while being pressed, the surface of the bent end  3  is more aesthetically pleasing than when heated from its front side. The roof molding  1  is fixed securely in the groove  12  of the roof  11  by the base  22  and the lip portion  23 .  
         [0030]     While the roof molding  1  and its manufacturing method have been described, the molding and its manufacturing method can be changed in the details of construction and in the combination and arrangement of parts without departing from the spirit and the scope of the invention as hereinafter claimed.  
         [0031]     The roof molding  1  has been described in the context of a roof molding. However, the molding is not limited to use as a roof molding. For example, the molding is also applicable as a bumper molding and a side molding, as well as to other molding configurations. Materials and construction can be changed according to the specific application. In addition, the base and the lip portion are not always both necessary. The shapes of the base and the lip portion are also not limited to those discussed, and can be changed based on the particular application. Further, although the base has been described as including a metal core, the metal core may not always be necessary.  
         [0032]     Still further, the bent end was described as being formed at one end of the molding. However, the bent end can be formed at both ends of the molding. Although the reinforcing ribs are formed in the shape of a parallelogram, the shape of the reinforcing ribs is not limited to such a shape as long as the reinforcing ribs are arranged at the boundary between the body and the bent end as discussed above. For example, the shape of the reinforcing ribs can be changed to a trapezoidal shape or a triangular shape. Furthermore, the thickness, as well as the number, of the reinforcing ribs is not limited to the above discussed parameters. One, two or more than four of the reinforcing ribs can be used. If two or more reinforcing ribs are used, the distance between adjacent ones of the reinforcing ribs can be changed according to the number used.  
         [0033]     The disclosure is intended to explain how to fashion and use various embodiments in accordance with the invention rather than to limit the true, intended and fair scope and spirit thereof. The forgoing description is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The embodiments were chosen and described to provide the best illustration of the principles of the invention and its practical application, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims, as may be amended during the pendency of this application, and all equivalents thereof, when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.