Abstract:
An exhaust system includes a flange assembly having multiple identical flange portions manufactured of a powdered metal. By assembling each flange assembly from identical flange portions, and utilizing powder metal, manufacturing expense is decreased.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to an exhaust system, and more particularly to a symmetrical flange assembly, which may be utilized in multiple locations throughout the exhaust system to connect exhaust pipe sections.  
         [0002]     Exhaust systems typically include several connected exhaust pipe sections. A flange on each exhaust pipe section commonly connects adjacent exhaust pipe sections. The flanges are typically rectilinear plates with a circular aperture that receives an end of each exhaust pipe section. Typically, the flanges have been stamped from sheet metal. The flanges are welded onto ends of the exhaust pipe sections and the flanges are attached together with fasteners.  
         [0003]     Due to size and strength requirements, the flanges may be expensive to manufacture. A large press has been required to stamp the flanges. The resulting expense of the flange may be a large percentage of the overall exhaust system expense.  
         [0004]     Accordingly, it is desirable to provide an inexpensive flange for an exhaust system.  
       SUMMARY OF THE INVENTION  
       [0005]     The exhaust system according to the present invention provides a flange assembly made from multiple flange portions. The flange portions may be formed of a powdered metal and may be identical. A flange portion formed from powdered metal may be manufactured by a less expensive manufacturing process than the prior art. The use of identical flange portions reduces the total number of parts that would otherwise be required to utilize varying flange portions.  
         [0006]     The disclosed flange portions include steps at each peripheral edge. The steps are approximately one-half a nominal thickness of the flange portion. Preferably, two flange portions come together to form the flange assembly. The steps at the peripheral edges of each flange portion overlap with a corresponding peripheral edge from the other flange portion. The steps arranged in this overlapping relationship provide a reliable structure for properly positioning the flange portions on an exhaust pipe section.  
         [0007]     The flange portions have a curved inner peripheral surface between the peripheral edges that extends beyond 180°. Thus, the steps will serve to hold and position the flange portions on the exhaust pipe section. Of course, it is possible the exhaust pipe section will have a shape other than circular, and the inner peripheral surface of the flange portions will be modified accordingly in such an instance.  
         [0008]     The present invention therefore provides an inexpensive alternative to the prior art flange for an exhaust system. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:  
         [0010]      FIG. 1  is a general exploded view of an exhaust system;  
         [0011]      FIG. 2  is a planar view of a flange portion of the present invention;  
         [0012]      FIG. 3  is a side view of the flange portion of the present invention; and  
         [0013]      FIG. 4  is an end view of a flange assembly attached to an exhaust pipe. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]      FIG. 1  illustrates an exhaust system  10 , including an exhaust pipe assembly  12  and a muffler assembly  14 . It should be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other exhaust systems will benefit from the instant invention.  
         [0015]     The exhaust pipe assembly  12  includes an exhaust pipe  16  and a flange assembly  18  mounted to an end segment  20  of the exhaust pipe  16  such as through welding. The muffler assembly  14  includes a muffler exhaust pipe  22 , a muffler  24 , and a flange assembly  26  mounted to an end segment  28  of the muffler exhaust pipe  22  such as through welding. The flange assemblies  18 ,  26  are attached together through a fastener arrangement, such as bolts  30  and nuts  32 . Other fasteners such as rivets can be utilized.  
         [0016]     Each flange assembly  18 ,  26  is disclosed as being assembled from identical flange portions  34 , and is manufactured of a powdered metal. Most preferably a stainless steel powdered metal is utilized, although other appropriate powdered metals could be utilized. Of course, each flange portion  34  is smaller than the assembled flange assembly  18 ,  26 . Because of the smaller size and the powdered metal composition, the flange portions  34  may be manufactured by a lower tonnage press to thereby decrease manufacturing expense. That is, the flange portions  34  are more economical to produce than conventional one-piece flanges. Furthermore, because each flange portion  34  is identical, the part count per exhaust system  10  is not increased.  
         [0017]     Referring to  FIG. 2 , a single flange portion  34  is illustrated. Each flange portion  34  is generally rectilinear and defines a partial circular pipe aperture  36  and a pair of fastener apertures  38 ,  40 . An index mark  42  is also preferably located along one side of the flange portion  34 . The index mark  42  provides assembly identification and assists in orientation of each of the flange portions  34  in a welding jig (not shown).  
         [0018]     As can be appreciated from  FIGS. 2 and 3 , each flange portion  34  has steps  46  that are approximately one-half the nominal thickness of the flange portion  34  at other locations. The steps  46  are formed at each peripheral edge  50  of the flange portion  34 . As will be best understood from  FIG. 4 , the steps  46  on two mating flange portions  34  assist in positioning and holding the flange portions  34  on the exhaust pipe  16 .  
         [0019]     Referring to  FIG. 4 , the flange assembly  18  is illustrated in an assembled condition. Although only flange assembly  18  will be described with reference to  FIG. 4 , it should be understood that the flange assembly  26  as well as other flange assemblies would be structured similarly.  
         [0020]     Plane A is defined as bisecting an open end  48  of the exhaust pipe  16 . One flange portion  34  is assembled on each side of the plane A such that the partial circular pipe apertures  36  from the two flange portions  34  form a complete aperture which surrounds the exhaust pipe  16 . The steps  46  at each end surface  52  of each flange portion  34  are overlapped with mating steps  46  from the other flange portion  34 . As can be appreciated, a curved inner peripheral surface  54 , defined by the partial circular pipe aperture  36 , extends beyond 180°. In this manner, the steps  46  cross the plane A, and thus have surfaces that will begin to curve back inwardly to catch each flange portion  34  on the exhaust pipe  16 . That is, since the steps  46  extend beyond 180°, they will begin curving back in an opposed direction near the peripheral edges  50 . This will assist in holding the flange portions  34  on the exhaust pipe  16 .  
         [0021]     The flange portions  34  are positioned within an appropriate welding jig, and held while being welded to the exhaust pipe  16 . Preferably, a weld joint W secures the flange portions  34  to the exhaust pipe  16  about the entire circumference of the exhaust pipe  16 . Of course, a partial weld joint may also be utilized. Notably, the index mark  42  on each flange portion  34  is located diagonally transverse to each other relative to plane A. The index mark  42  on each flange portion  34  assists in properly positioning the flange portion  34  within the welding jig.  
         [0022]     While the flange portions  34  are shown as fully surrounding the exhaust pipe  16 , the present invention would extend to the use of multiple flange portions formed of powdered metal that do not necessarily fully surround the exhaust pipe  16 . Moreover, while the two flange portions  34  that come together to define a flange assembly  18  are shown as identical, the present invention would also extend to flange assemblies formed of multiple flange portions that are not identical. In addition, while two flange portions  34  are shown as providing the flange assembly  18 , more than two flange portions may also be utilized.  
         [0023]     The foregoing description is exemplary rather than defined by the limitations within. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.