Abstract:
The integration of two separate manufacturing processes involving joining two pieces of metal using a clinching or Tog-L-Loc™ type of connection, while also injecting a molten material around the two pieces of metal to create the desired part. A process for creating the desired part made of both plastic and metal includes the steps of providing a first metal component, a second metal component, inserting the first metal component into a mold, and inserting the second metal component into the mold. At least one connection point is used for connecting the first metal component to the second metal component while the metal components are located in the mold. Molten material, such as a thermoplastic, is injected into the mold around the first metal component and the second metal component, forming the desired part using the first metal component, the second metal component, and the hardened molten material.

Description:
This application claims the benefits of U.S. Provisional Application No. 61/274,274, filed Aug. 14, 2009. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the reduction of steps in the manufacturing process of a part made from injection molded plastic and more than one metal component. 
     BACKGROUND OF THE INVENTION 
     Injection molding is a commonly used process in which molten material is injected into a cavity, or mold, to form a desired part of a specific shape. Injection molding is used to create many different types of parts used in automotive, computer, household, or other applications. 
     One type of injection molding process also includes the forming of a part made of both metal and a type of plastic, where the plastic is in a molten form and injected into a mold containing the portion of the part made of metal. The plastic forms in an overmold around the metal material into the desired shape. The finished part is therefore made of both plastic and metal. 
     Additionally, parts made of more than one piece of metal, such as sheet metal, are often connected together through the use of what is referred to as “clinching.” Sheet metal clinching involves the connection of two pieces of metal without additional components, and an interlock is formed between the two sheets. This type of connection is also referred to as a “Tog-L-Loc™” process, which is a trademark for a process used by BTM Corporation of Marysville, Mich. 
     When parts made of plastic and multiple pieces of metal are created using both clinching and injection molding, there are two different stages of the manufacturing process used. One stage is the connection, or clinching, of the metal pieces. Another stage includes the placement of the connected metal pieces into a mold, and injecting a molten material around the metal pieces such that the desired portion of the finished part which is made of plastic is formed properly around the two pieces of metal. 
     However, using these two stages to form the desired part is costly. Accordingly, there exists a need for an improved method of manufacturing a part made of plastic and metal, which reduces the steps required in the manufacturing process. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to the integration of two separate manufacturing processes involving joining two pieces of metal using a clinching or Tog-L-Loc™ type of connection, while also injecting a molten material around the two pieces of metal to create the desired part. 
     The present invention is directed to a process for creating a component made of both plastic and metal which includes the steps of providing a first metal component, a second metal component, inserting the first metal component into a mold, and inserting the second metal component into the mold. At least one connection point is used for connecting the first metal component to the second metal component while the metal components are located in the mold. Molten material, such as a thermoplastic, is injected into the mold around the first metal component and the second metal component, forming the desired part using the first metal component, the second metal component, and the hardened molten material. 
     The process according to the present invention also includes providing a punch portion having a small diameter portion and a large diameter portion. The punch portion is mounted within and attached to a first half of the mold, and a die portion is mounted within and attached to a second half of the mold. The punch portion is positioned in the first half of the mold such that the small diameter portion of the punch portion is properly aligned with the areas of the first metal component and the second metal component that are to be used to form the connection point. As each half of the mold is brought together, a force is applied to the large diameter portion such that an area of the first metal component and an area of the second metal component are displaced into the die to form the at least one connection point. 
     In one embodiment, the small diameter portion of the punch portion is placed in contact with the first metal component to displace a first area of material of the first metal component as the first half of the mold and the second half of the mold are brought together. A second area of material of the second metal component is also displaced as the small diameter portion of the punch portion displaces the first area of material. This forms an interlock using the first area of material with the second area of material, forming the clinch. 
     In one embodiment, the process according to the present invention is used to create a carrier for a vehicle, but it is within the scope of the invention that the process according to the present invention may be used to create other components as well. In another embodiment, the first metal component is a first piece of sheet metal, and the second metal component is a second piece of sheet metal. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a first enlarged perspective view of a carrier for an automobile, assembled using a process according to the present invention; 
         FIG. 2  is an enlarged front view of a carrier for an automobile, assembled using a process according to the present invention; 
         FIG. 3  is a first enlarged perspective front view of a carrier for an automobile, assembled using a process according to the present invention; 
         FIG. 4  is a second enlarged perspective front view of a carrier for an automobile, assembled using a process according to the present invention; 
         FIG. 5  is a first enlarged perspective rear view of a carrier for an automobile, assembled using a process according to the present invention; 
         FIG. 6  is a second enlarged perspective view of a carrier for an automobile assembled using a process according to the present invention; 
         FIG. 7  is a perspective view of a clinch used for connecting two metal components used in the assembly of a carrier for an automobile, assembled using a process according to the present invention; 
         FIG. 8  is a sectional side view of a clinch used for connecting two metal components used in the assembly of a carrier for an automobile, assembled using a process according to the present invention; 
         FIG. 9A  is a second enlarged perspective view of a carrier a carrier for an automobile, assembled using a process according to the present invention; 
         FIG. 9B  is an enlarged view of the circled portion of  FIG. 9A ; 
         FIG. 10  is a perspective view of a mold used for assembling a carrier, according to the present invention; 
         FIG. 11  is an exploded view of a mold used for assembling a carrier, according to the present invention; 
         FIG. 12  is a top view of a core half of a mold used for assembling a carrier, according to the present invention; 
         FIG. 13A  is a schematic of a sectional view taken along lines  13 A- 13 A of  FIG. 10 ; 
         FIG. 13B  is an enlarged view of the circled portion shown in  FIG. 13A ; 
         FIG. 13C  is an enlarged view of the circled portion shown in  FIG. 13B ; and 
         FIG. 14  is a flow diagram showing a process for creating a component made of both plastic and metal, according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     An embodiment of a part made in accordance with the present invention is shown in the Figures generally at  10 . In this embodiment, the part  10  is a carrier for the front end of a vehicle (not shown), suitable for supporting various components, such as a radiator, headlamps, a horn, and the like. However, it is within the scope of the invention that that other parts may be made in accordance with the present invention. The carrier  10  includes two components made of metal, a first metal component or a front sheet  12  and a second metal component or a rear sheet  14 . However, it is within the scope of the invention that other amounts of sheets may be used. The sheets  12 , 14  are pre-formed to a desired shape. Also included is a composite panel  16 , which is made of an injection molded material, such as plastic. 
     During the assembly of the sheets  12 , 14  and the panel  16 , the front sheet  12  is placed into a mold, shown generally at  34 , or cavity, in the desired position relative to the rear sheet  14 , which is also placed in the mold. This is also shown in steps  56  and  58  in  FIG. 14 . The mold  34  is shaped in the form of the desired finished part, in this case the carrier  10 . The mold  34  also includes a die portion  30 , and a punch portion  20  having a large diameter portion  22  and a small diameter portion  24 . The mold  34  has two halves, a first half or cavity half, generally shown at  36 , and a second half or core half, shown generally at  38 . These steps are also shown at  60 , 62 , 64 , 66  in  FIG. 14 . In this embodiment, the punch portion  20  is mounted within the first half  36  of the mold  34 , shown at step  68 , and the die portion  30  is mounted within the second half  38  of the mold  34 , shown at step  70 . The punch portion  20  receives pressure from a spring  48  and a pin  50 , and the pin  50  is mounted within the first half  36  of the mold  34 . The die portion  30  is supported by a pin  52  mounted in the second half  38  of the mold  34 . The sheets  12 , 14  are placed in the mold  34  in the desired location relative to one another such that when the process is complete, they are properly connected. 
     After the sheets  12 , 14  are correctly placed in the mold  34 , the mold halves  36 , 38  are brought together. Although it is shown that the first half  36  is movable and the second half  38  is stationary, it is within the scope of the invention that in other embodiments the first half  36  is stationary and the second half  38  is movable, or both the first half  36  and the second half  38  are movable. There are alignment pins  46  which are used for providing proper alignment between each half  36 , 38  of the mold  34  and the sheets  12 , 14  as the halves  36 , 38  are brought together. As each half  36 , 38  of the mold  34  is brought together, the small diameter portion  24  contacts the front sheet  12 , and force is applied to the large diameter portion  22  by the first half  36  of the mold  34 , therefore causing an increased amount of pressure to be transferred from the small diameter portion  24  to the front sheet  12 . The area of the front sheet  12  in contact with the small diameter portion  24  is pressed, or “punched,” along with a portion of the rear sheet  14  into the die portion  30  (as the halves  36 , 38  of the mold  34  are brought together) to clinch the front sheet  12  to the rear sheet  14  to form a connection point or a clinch  18 , which is shown in  FIG. 14  at step  72 . 
     Referring again to the Figures generally, a clinch  18  formed to connect the two sheets  12 , 14  is shown. After the punch is completed, it can be seen that an area of material or first area, shown generally at  26 , of the front sheet  12  has been displaced or deformed, and is interlocked with a corresponding area of material or second area, shown generally at  28 , of the rear sheet  14 , which has also been displaced, or deformed. The interlock, shown generally at  32 , is formed by the area of material  26  of the front sheet  12  and the area of material  28  of the rear sheet  14  deformed together to create the clinch  18 , and securely connects the front sheet  12  to the rear sheet  14 . Essentially, as the halves  36 , 38  of the mold  34  are brought together, the area of material  26  of the front sheet  12  and the area of material  28  of the rear sheet  14  is displaced or punched into a recess  40  formed as part of the die  30 , which is also shown at step  74  in  FIG. 14 . The shape of the small diameter portion  24  and the recess  38  define the shape of the clinch  18 . 
     In this embodiment, there are two clinches  18  shown; however, it is within the scope of the invention that more or less clinches  18  may be used. Once clinches  18  are formed, the punch portion  20  remains in contact with the area of material  26  of the front sheet  12  that has been displaced, and both the area of material  26  of the front sheet  12  and the area of material  28  of the rear sheet  14  remain within the die portion  30  as molten material is injected into the mold  34  in the areas around the joined sheets  12 , 14  as dictated by the shape of the mold  34 , thereby forming the composite panel  16 , completing the formation of the carrier  10 . This is best seen in  FIG. 13C , where the punch portion  20  is in contact with the front sheet  12  and the die portion  30  is in contact with the rear sheet  14 . Essentially, the molten material is injected into the mold  34  prior to the punch portion  20  being pulled away from the die portion  30 . With the punch portion  20  mounted to the first half  36  and the die portion mounted to the second half  38 , this eliminates the need for any type of device in the mold  34  to separate the die portion  30  and punch portion  20  from each other. 
     There are two different embodiments of the punch portion  20  shown in the Figures, one embodiment is shown in  FIGS. 3 and 8 , and another embodiment of the punch portion  20  is shown in  FIGS. 13A-13C . While two embodiments of the punch portion  20  are shown in the Figures, it is within the scope of the invention that the punch portion  20  (and the die portion  30 , if desired) may be of different shapes to form different types of clinches  18 . It is also intended that the clinches  18  may be any type of metal deformation or displacement used to form a connection between two parts, such as the sheets  12 , 14 . 
     The embodiment of the punch portion  20  shown in  FIGS. 3 and 8  has a longer small diameter portion  24  compared to the small diameter portion  24  shown in  FIGS. 13A-13C . With specific reference to  FIGS. 13A-13C , the small diameter portion  24  of the punch portion  20  is adjacent a first support surface  42 , and the first support surface  42  is in contact with the front sheet  12  and surrounds the material  26  of the front sheet  12  displaced by the small diameter portion  24 . There is a second support surface  44  formed as part of the die portion  20  which is adjacent the recess  40 . When the carrier  10  is placed in the mold  34 , the second support surface  44  contacts the rear sheet  14  and surrounds the material  28  of the rear sheet  14  displaced by the small diameter portion  24 . The function of each of the support surfaces  42 , 44  is to support the respective sheets  12 , 14  as the clinch  18  is formed. Portions of each of the sheets  12 , 14  are located between the support surfaces  42 , 44 , and are prevented from moving as the area of material  26  of the front sheet  12  and the area of material  28  of the rear sheet  14  are displaced by the small diameter portion  24  of the punch portion  20 , best seen in  FIG. 13C . 
     Referring to  FIGS. 3 and 8 , if desired, the small diameter portion  24  of the punch portion  20  may be longer if desired, and the use of the first support surface  42  may be eliminated. The increased length of the small diameter portion  24  of the punch portion  20  may be used to create a different type of clinch  18 , depending upon the application. A tapered surface  54  may optionally be formed as part of the small diameter portion as shown in  FIGS. 3 and 8 , which also creates a different type of clinch  18 . 
     It can be seen in  FIGS. 9A-13C  that plastic material which makes up the composite panel  16  is injected and able to flow into the mold  34  and be unaffected by the location or placement of the clinches  18 . The present invention therefore provides the unique advantage of reducing the number of steps in the manufacturing process involving creating a part by clinching in a separate machine, and then placing the clinched part into an injection molding machine to form the completed part. The present invention eliminates clinching as a separate step from injection molding. The sheets  12 , 14  are assembled using the clinches  18 , and the molten material is injected into the mold, finishing the carrier  10 . This combines the processes of clinching two pieces of material together in a mold and injection molding a molten material into the mold as a single process, improving manufacturing efficiency. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the essence of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.