Abstract:
A cooking apparatus and methods of forming are provided. The cooking apparatus has a cooking surface, a sidewall depending from the cooking surface, and a handle is provided. The handle has a saddle portion and a gripping portion. The saddle portion includes a first opening defined therethrough and a first recess defined about the first opening. The saddle portion is adjacent the sidewall so that the first recess defines a first gap between the sidewall and the saddle portion. A first rivet secures the handle to the sidewall. The rivet has a first weldament in the first gap, a first shaft in the first opening, and a first head abutting the handle and covering the first opening.

Description:
BACKGROUND OF THE INVENTION 
   The present disclosure is related to a cooking apparatus, such as a pot, a pan, a wok, and the like. More particularly, the present disclosure is related to a cooking apparatus and methods of forming. 
   Cooking apparatus or cookware typically includes a cooking surface, a depending sidewall, and a handle attached to the sidewall. The cooking surface and wall are adapted to receive the food to be cooked. Heat can be conducted through the cooking surface from a heat source, such as a stove or oven, to cook the food thereon. The handle allows the user to move the cookware as desired, often times while the cooking surface is at an elevated temperature. 
   Accordingly, it has traditionally been desired to insulate and/or isolate the handle from heat conducted into the cooking surface and/or wall. For example, one solution has been to provide the cooking surface and wall of a highly conductive metal such as aluminum or aluminum alloys, with a handle of a different, lower conductive metal such as steel or iron. In this manner, heat conducted into the cooking surface quickly and evenly spreads across the cooking surface to evenly cook food thereon. However, the conduction of heat into the handle is slowed by the lower conductivity of the handle. 
   The handle and sidewall made of dissimilar metals has presented challenges in connecting the handle to the sidewall in an easy to clean, inexpensive, secure manner. For example, directly welding dissimilar metals to one another, namely the steel handle to the aluminum wall, is not possible. Thus, it has been necessary to secure or attach the handle to the wall with mechanical means, such as rivets, bolts, and the like. This solution has proven effective at maintaining a tight attachment between the wall and the handle. However, this solution requires a portion of the rivets or bolts to protrude through the wall into the cooking area, which can form areas that trap food particles and/or are difficult to clean. 
   Accordingly, there is a continuing need for cookware handle attachments and methods of forming that resolve or mitigate one or more of the aforementioned and other defects and deficiencies of the prior art. 
   SUMMARY OF THE INVENTION 
   A cooking apparatus having a cooking surface, a sidewall depending from the cooking surface, and a handle is provided. The handle has a saddle portion and a gripping portion. The saddle portion includes a first opening defined therethrough and a first recess defined about the first opening. The saddle portion is adjacent the sidewall so that the first recess defines a first gap between the sidewall and the saddle portion. A first rivet secures the handle to the sidewall. The rivet has a first weldament in the first gap, a first shaft in the first opening, and a first head abutting the handle and covering the first opening. 
   A method of forming a cooking apparatus is also provided. The method includes positioning a handle with respect to a cooking surface wall so that a saddle portion of the handle is adjacent the cooking surface wall; inserting a first rivet into a first opening defined in the saddle portion so that a first shaft of the first rivet contacts the cooking surface wall, the first rivet being formed of a third material weldable to the first material; inducing a current through the first rivet and the cooking surface wall so as to weld the first shaft and the cooking surface wall to one another and so that a first portion of the first shaft expands into a first gap defined between the cooking surface wall and the saddle portion at the first opening; and deforming the first rivet to abut a first head of the first rivet with the saddle portion and to cover the first opening. 
   The above-described and other features and advantages of the present disclosure will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded sectional view of a piece cookware according to an exemplary embodiment of the present disclosure; 
       FIG. 2  is an exploded top view of the cookware of  FIG. 1 ; 
       FIG. 3  is an end view of an exemplary embodiment of a handle for the cookware of  FIG. 1 ; 
       FIG. 4  is a sectional view of the cookware of  FIG. 1  in a first assembled state; 
       FIG. 5  is a section view of the cookware of  FIG. 1  in a second assembled state; and 
       FIG. 6  is a section view of the cookware of  FIG. 1  in a third assembled state. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to the drawings and in particular to  FIGS. 1 and 2 , a cooking apparatus or cookware  10  according to an exemplary embodiment of the present disclosure is illustrated in an exploded sectional view. Cookware  10  includes a cooking surface  12  and a sidewall  14 . Surface  12  and sidewall  14  define a cooking area  16  of cookware  10 . Cooking area  16  can include a non-stick coating (not shown), such as, but not limited to TEFLON, disposed thereon. 
   Cookware  10  is illustrated having a circular or curved shape when viewed from above ( FIG. 2 ) and having a curved sidewall when viewed from the side (FIG.  1 ). Of course, it is contemplated by the present disclosure for cookware  10  to have any desired shape when viewed from above such as a circular shape, a polygonal shape, and combinations thereof. In addition, it is also contemplated by the present disclosure for cookware  10  to have sidewall  14  with any desired shape when viewed from the side such as a curved, linear, and combinations thereof. 
   Cooking surface  12  is formed from a first material. The first material is, preferably, a highly heat conductive material. For example, the first material can be aluminum, aluminum alloy, copper, or other conductive materials. Sidewall  14  depends upwardly from cooking surface  12  and is also formed of the first material. In an exemplary embodiment, sidewall  14  is integrally formed as a one piece or unitary element with cooking surface  12 . It should be recognized that cooking surface  12  and sidewall  14  are illustrated by way of example as being integrally formed of the same material. Of course, it is contemplated by the present disclosure for cooking surface  12  and sidewall  14  to be made of different materials and/or to be non-integrally formed. 
   Cookware  10  includes a handle  18  formed from a second material. The second material is, preferably, a low heat conductive material. For example, the second material can be steel, iron, steel alloy, or other poor heat conducting materials. In a preferred embodiment, handle  18  is formed of zinc coated steel. 
   Handle  18  has a saddle portion  20  and a gripping portion  22 . Saddle portion  20  is configured to be secured against sidewall  14 . Specifically, saddle portion  20  has an opening  24  defined therethrough for receiving a rivet  26 . Rivet  26  has a shaft  28  and a head  30 . Rivet  26  and is formed of a third material that can be welded to the first material of sidewall  14 . For example, the third material of rivet  26  can be the same as the first material of sidewall  14 . In addition, saddle portion  20  has a recessed area  32  defined about opening  24  at an inner side of the saddle portion as illustrated in FIG.  3 . 
   It should be recognized that cookware  10  is illustrated for purposes of clarity having one rivet  26  and one opening  24 . Of course, it is contemplated by the present disclosure for cookware  10  to have two or more rivets  26  and openings  24 . For example, it is contemplated for cookware  10  to have two rivets  26  for receipt in two openings  24  positioned horizontally with respect to one another as illustrated in phantom in  FIGS. 2 and 3 . Alternately, it is contemplated for cookware  10  to have two or more rivets and openings that are positioned vertically with respect to one another or for the openings. In addition, it should be recognized that opening  24  and rivet  26  are illustrated for purposes of clarity having a circular cross section. Of course, it is contemplated by the present disclosure for the opening  24  and/or rivet  26  of cookware  10  to have a non-circular cross section. In addition, it is contemplated by the present disclosure for cookware  10  to have more than two openings  24  and rivets  26 . 
   Cookware  10  is illustrated in various stages of assembly in  FIGS. 4 through 6 . Specifically, cookware  10  is illustrated in a first assembled state  34  in  FIG. 4 , in a second assembled state  36  in  FIG. 5 , and in a third assembled state  36  in FIG.  6 . 
   In first assembled state  34 , handle  18  is positioned in a selected location with respect to sidewall  14 . Here, saddle portion  20  is in contact with sidewall  14  so that recessed area  32  defines a gap  40  between the handle and the sidewall. Rivet  26  is disposed through opening  24  in handle  18  so that shaft  28  is in contact with sidewall  14 . In the illustrated embodiment, shaft  28  has a length sufficient to ensure head  30  does not contact handle  18  in this first assembled state  34 . 
   In second assembled state  36 , shaft  28  of rivet  26  is welded to sidewall  14 . For example, rivet  26  can be electrically resistive welded to sidewall  14  using known mid-frequency direct current (MFDC) resistive welding practices. During welding of rivet  26 , an electrical current is induced in rivet  26  and sidewall  14  to cause the rivet and sidewall to melt and, thus, weld to one another. In addition, gap  40  allows a portion or weldament  42  of the molten rivet to expand and fill substantially all of the gap. It has also been determined that gap  40  mitigates expansion of molten rivet back through opening  24  (e.g., flashback) and impinging on head  30 . It is believed that gap  40  provides an area of expansion for weldment  42 , which mitigates flashback. 
   In some embodiments, rivet  26  can include a beveled end  44  opposite head  30 . Beveled end  44  has a diameter that is smaller than the diameter of shaft  28 . It has been found that beveled end  44  can also mitigate instances of flashback. It is believed that bevel end  44  also provides an area of expansion for weldment  42 , which mitigates flashback. Advantageously, the reduction in diameter of shaft  28  (i.e., beveled end  44 ) reduces the amount of surface contact between sidewall  14  and rivet  26 . It has been determined that the decrease in surface contact provided by beveled end  44  also reduces that amount of current necessary to form weldament  42 . For example, in one exemplary embodiment shaft  28  has a diameter of about 0.281 inches, while beveled end  44  has a diameter of about 0.187 inches. Rivet  26  having beveled end  44  requires about 5% less current than a similarly sized rivet lacking the beveled end. 
   Accordingly, it has also been determined that gap  40  and/or end  42  mitigates flashback. Thus, cookware  10  has a larger weld area than would be possible without the gap and/or beveled end  44 , while weldament  42  seals the gap to reduce instances of food particles being harbored therein, at a lower cost than previously possible. 
   In third assembled state  38 , rivet  26  is deformed or coined to eliminate any space or gap between head  30  and handle  18 . For example, head  30  abuts handle  18  after coining. This ensures a tight fit between handle  18  and sidewall  14 . In addition, the coined head  30  completely covers openings  24  in handle  18  to mitigate food particles for becoming trapped in the opening. 
   It has been found that welding rivets  26  onto sidewall  14  as described above, namely after placement of handle  18  adjacent to the sidewall, also mitigates many of the problems and costs associated with prior systems having pre-welded studs. Specifically, it has been found that the method of the present disclosure mitigates the costs and problems encountered when studs are welded on the sidewall before the handle is placed into position. 
   For example, prior pre-welded systems required either the opening in the handle to be slotted or oversized and/or required tighter manufacturing tolerances in the cookware. The interaction of the location of the pre-welded stud, the shape of the sidewall, the shape of the handle&#39;s saddle, and the location of the opening in the saddle require either very costly manufacturing controls to ensure that the pre-welded stud fits into the opening. Alternately, the interaction of these variables requires that the opening be oversized to accommodate tolerances in one or more of these variables. 
   In one prior solution for circular cookware, the shafts of the pre-welded studs were formed along the radius of the cookware. In order for the openings in the handle to fit over such radial studs, the openings were slotted or oversized. However, the oversized openings have proven too large to be completely covered by coining the stud or by the use of a nut, which allowed food particles to be harbored therein. Alternate prior solutions for circular cookware formed the pre-welded studs parallel to the desired axis of the handle, namely not along the radius of the cookware. However, this method has proven to be costly and imprecise. Again, the oversized openings have proven too large to be completely covered by coining the stud or by the use of a nut, while the increased manufacturing tolerances have increased to cost of manufacture. 
   The placement of the pre-welded stud is made even more difficult in cookware having a curved or non-linear sidewall. The curvature of such a sidewall has also traditionally required the opening in the handle to be slotted or oversized. Again, the oversized openings have proven too large to be completely covered by coining the stud or by the use of a nut. 
   In contrast, the method of the present disclosure provides opening  24  having a dimension that is equal to or only slightly larger than the diameter rivet  26 . For example, opening  24  has a dimension is about 0% to about 20% larger than rivet  26 , preferably about 10% to about 17%, with about 12% being most preferred. Thus, the method of the present disclosure not only mitigates the need for the costly increased manufacturing tolerances of prior systems, but also ensures that openings  24  are completely covered by head  30  to reduce areas that could harbor hard to clean food particles. Moreover, the method of the present disclosure allows opening  24  to be sized with respect to rivet  24  irrespective of the whether sidewall  14  is circular and/or curved. 
   In this manner, cookware  10  has a securely attached handle  18  that is riveted into the selected position without portions of rivet  26  protruding into cooking area  16 . In addition, the connection between handle  18  and sidewall  14  mitigates gaps that could trap food particles. Thus, cookware  10  provides both a cooking area that is smooth for easy cleaning and non-harboring of food particles and an easy to clean outer surface. In addition, cookware mitigates the need for costly and time consuming process controls of prior systems. 
   Referring again to  FIG. 5 , an alternate embodiment of second assembled state  36  is illustrated in phantom. Here, the MFDC resistive welding process includes a welding contact  46  for inputting electricity into cookware  10  during welding. Contact  46  includes a shaped surface  48  configured to correspond to a desired shape of head  30  after coining. In this embodiment, contact  46  is configured to reciprocate in a direction  50  along the axis of shaft  28  of rivet  26 . Thus, contact  46  allows the welding and coining processes to occur substantially simultaneous to one another. 
   It should also be noted that the terms “first”, “second”, “third”, “upper”, “lower”, and the like may be used herein to modify various elements. These modifiers do not imply a spatial, sequential, or hierarchical order to the modified elements unless specifically stated. 
   While the present invention has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the scope thereof. Therefore, it is intended that the present invention not be limited to the particular embodiment(s) disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.