Patent Publication Number: US-2006017195-A1

Title: Method for injection molding a solid pattern onto a shoe upper

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to a method for injection molding a solid pattern onto a shoe upper, which is capable of overcoming the defect of the prior art that it is unable to molding solid pattern on a shoe upper, which includes the following steps: 1. shoe upper stretching process 2. tightening a lower periphery of the shoe upper material 3. upper mold pressing process 4. injection molding process 5. cleaning up the final product.  
      2. Description of the Prior Arts  
      Existing plastic injection molding technology is unable to mold solid pattern onto leather or fabric shoe upper directly, and the defects of the existing plastic injection molding methods are to be explained as follows:  
      First, the existing technology is unable to stretch the leather or the fabric shoe upper tight enough, the technology of prior art is still at the research stage, which greatly limits diversity of the appearance and the function of the shoe products.  
      Second, if the conventional method is used to mold plastic onto the shoe upper, since many production equipments are involved, it is impossible for the operator to check all the details. The surface of the shoe upper is likely draped, in this case, not only the injection-molding pattern is failed, but also the appearance of the shoes will be ugly.  
      The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.  
     SUMMARY OF THE INVENTION  
      The primary object of the present invention is to provide a method for injection molding a solid pattern onto a shoe upper, which is capable of overcoming the defect of the prior art, and generally including the following steps: 1. shoe upper stretching process 2. tightening a lower periphery of the shoe upper material 3. upper mold pressing process 4. injection molding process 5. cleaning up the final product.  
      The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a flow chart in accordance with the present invention for showing the steps of injection molding a solid pattern onto a shoe upper;  
       FIG. 2  shows the shoe upper is place on the last;  
       FIG. 3  shows the shoe upper is being stretched on the last;  
       FIG. 4  shows a lower periphery of the shoe upper is being stretched and tightened;  
       FIG. 5  shows the upper mold is pressing down;  
       FIG. 6  is a cross sectional view of a final product in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      A method for injection molding a solid pattern onto a shoe upper in accordance with a preferred embodiment of the present invention is shown in  FIGS. 1-6 , which generally includes the following steps (the shoe upper material in this embodiment is leather):  
      First, shoe upper stretching process  10 : with reference to  FIGS. 1-3 , initially, the worker has to made a plurality of positioning apertures  111  on the periphery of a leather material  11  (or fabric), and placing the leather material  11  (or fabric material) on a last  12 . After that, plural pins  13  of stretching rod  14  are inserted in the respective positioning apertures  111  of the leather material  11  which is to be tightly stretched by the extendable stretching rod  14 , so that the leather material  11  is enabled to abut closely on the last  12 .  
      Second, process  20  for tightening the lower periphery of the leather: with reference to  FIG. 4 , after the leather material  11  is stretched by the stretching rod  14 , plural oblique leaders  23  are employed to move a pair of outer sliding blocks  21  having cavities  211  inwardly towards the leather material  11 . At the start of the moment, an extendable stretching mold  22  at the lower periphery of the respective outer sliding blocks  21  stretches out to push the lower periphery of the leather  11  inward and make it tight. The last  12  is provided with grooves  221  corresponding to the stretching mold  22 , which is designed to enable the leather material  11  to abut tightly against the last  12 .  
      Third, upper mold pressing process  30 , as shown in  FIG. 5 , pressing an upper mold  31  having a cavity  311  on the surface of the leather material  11 .  
      Fourth, injection molding process  40 : as shown in  FIG. 5 , in this process, the injection molding machine injects injecting molding material A into the cavities  211  of the outer sliding blocks  21  and the cavity  311  of the upper mold  31 , respectively. Since the leather material  11  has been tightened, the material A can be integrally and firmly molded onto the surface of the leather material  11 , and creating a solid pattern.  
      Fifth, process  50  for cleaning up the final product: after being taken out of the mold, the surface of the leather material  11  is molded with the injection molding material A that corresponds to the cavities  211  of the outer sliding blocks  21  and the cavity  311  of the upper mold  31 .  
      The shoe upper stretching process  10  and the process  20  for stretching the lower periphery of the leather material  11  are able to stretch tight and position the lower periphery of the leather material  11  by employing the stretching rods  14 . Furthermore, the moveable stretching molds  22  is able to inwardly tighten the lower periphery of the leather material  11 . Thus, the leather material  11  is able to form a flat surface corresponding to the last  12 , so that the injection molding material A is firmly molded onto the surface of the leather material  11  in a 3-D manner.  
      It is to be noted that the outer sliding blocks  21  and the upper mold  31  are well known in the prior art and are not limited to the shapes described above. The effect of the present invention is only achievable with the stretching molds  22 . And other molding technologies are known in the art. In addition, the last  12  is movable and extendable so as to enhance the tightening effect of the shoe upper.  
      While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.