Abstract:
A method of making Circular and Oval Flanged Rings, for the connection of thin walled circular and oval ducting, including Circular and Oval Flanged Rings having a Sheet Metal and Air Conditioning Contractors National Association (SMACNA) standard T24 Profile. Thin gauge Lock Form Quality steel, from 10 to 20 gauge, is cut into strips with the strip ends butt welded forming Flanged Ring Band Stock which is inserted and clamped into a Spinning Die. The Spinning Die is rotated by a horizontally configured lathe output shaft presenting the extended portion of the Flanged Ring Band Stock for machine tool forming. Standard machine tools are used to form the Flanged Ring Band Stock into a Circular Flanged Ring including the SMACNA T24 Flanged Ring Profile. A Circular Flanged Ring is cut along a diameter into Semi-circular Flanged Ring Portions; straight segments including segments with SMACNA T24 Linear Segments are roll formed, assembled into a oval shape within a fixture and welded forming the Oval Flanged Ring. The method of making and the Circular and Oval Flanged Rings are disclosed.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation prior application Ser. No. 09/956,745, filed Sep. 17, 2001 now abandoned, which is a continuation of application Ser. No. 09/484,741, filed Jan. 18, 2000, now U.S. Pat. No. 6,289,706, which is a continuation-in-part of application Ser. No. 09/441,037, filed Nov. 16, 1999 now U.S. Pat. No. 6,301,781, which is a continuation-in-part of application Ser. No. 08/616,655, filed Mar. 15, 1996, now U.S. Pat. No. 5,983,496. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to Circular and Oval Flanged Rings for connecting oval and circular heating, ventilation and air conditioning (HVAC) ducting sections, from thin gauge Lock Form Quality steel, and a method for spin-forming such Flanged Rings. 
     BACKGROUND OF THE INVENTION 
     Joint assemblies are well known for the connection of the ends of adjacent rectangular, circular and oval HVAC duct sections. U.S. Pat. No. 5,129,690 to Meinig recites prior art relating to such assemblies and discloses an apparatus for connecting the ends of oval duct sections without disclosure of the method of making the apparatus; the patent does refer to U.S. Pat. No. 4,516,797 to Meinig which discloses a one-piece flanged ring for connecting the ends of circular duct sections. U.S. Pat. No. 4,516,797 discloses a method for producing the flanged ring by contouring and then bending an elongated sheet-metal strip into an annular shape resulting in a flanged ring having an axial slit and claiming a method for producing a flanged ring characterized as an elongated sheet metal strip which is contoured and subsequently bent into annular form. 
     The machine method used to produce such a flanged ring is known to include roll forming. However, roll forming is limited generally to sheet-metal less than 10 gauge with roll forming causing tearing or breaking of sheet-metal in the production of flanged rings from thinner sheet-metal of gauge  10  or greater. Circular flanged rings, produced by roll forming, and thin-walled sheet-metal ducting generally do not have an absolutely circular cross section. The predominate means of manufacturing HVAC ducting is in the form of spiral seam tubes made up of helical wound sheet-metal strips with the strips interconnected by means of lock seams. The lock seams stand out from the outer duct face. 
     U.S. Pat. No. 4,516,797 and No. 5,129,690 to Meinig are identified and disclosed in accordance with 37 CFR 1.97. 
     SUMMARY OF THE INVENTION 
     An object of this invention is to make, by spinning, forming and trimming, with standard machine tools and machining processes, Circular and Oval Flanged Rings from Lock Form Quality steel of gauge  10  to  20 , for the connection of the ends of thin-walled circular and oval sheet-metal tubes or ducting. The present invention is capable of making Flanged Rings that comply to the T24 flange profile of the Sheet Metal and Air-Conditioning Contractors National Association (SMACNA). The method requires LFQ steel strips to be rolled into Flanged Ring Band Stock Strips having Strip First and 
     Second Ends which are butt welded together with a tungsten inert gas process with no filler. A Spinning Die, which is balanced and which has structure means or supporting structural member means, receives the Flanged Ring Band Stock which is secured within the Spinning Die by appropriate means, for example by clamp means. The Spinning Die is rotated by means, for example by a lathe, and standard machine tools are employed to stretch, form and trim the Flanged Ring Band Stock to produce a Circular Flanged Ring for the connection of circular and oval thin gauged pipe or ducting sections. 
     The preferred embodiment of flanged ring profile described herein constitutes the Sheet Metal and Air-Conditioning Contractors National Association (SMACNA) standard T24 Flange Profile. The profile disclosed is not limited to the SMACNA T24 profile. However, the method disclosed produces Circular or Oval Flanged Rings while the SMACNA T24 Flange Profile references solely to flanges for the connection of rectangular ducting sections. This disclosure is the only known method of producing the SMACNA T24 Flange Profile for Circular and Oval Flanged Rings from 10 or greater gauge LFQ steel. The SMACNA T24 Flange Profile or cross section produced by the method described has an Insertion Flange portion which is secured within the Spinning Die by means including clamp means, a Mating Flange portion which is stretched and formed and which meets and matches an opposing mating flange portion, a Hem portion which is formed and a Return Flange. 
     The Oval Flanged Ring is produced by cutting a Circular Flanged Ring along a diameter to produce approximately equal sized semi-circular Flanged Ring Portions. Equal length SMACNA T24 Linear Segments of the SMACNA T24 Flange Profile are produced, for instance by roll forming, and are welded to the Semi-circular Flanged Ring Portions to produce the Oval Flanged Ring. 
     The preferred embodiment of the present disclosed method results in the production of the SMACNA T24 Flange Profile from 10 to 20 gauge Lock Form Quality steel (under 30,000 psi yield/tensile, galvanized G60; however, any metal which can be turned in the following described process and which can be welded may be used for production). The preferred embodiment of the described method requires the preparation of Flanged Ring Band Stock from 3.87511 wide 10 to 20 gauge LFQ steel. The material and material width may be varied as preferred. 
     An additional object of this invention is the formation of a Circular Flanged Ring which is more nearly circular in cross section than flanges produced by other means. The truer circular cross section facilitates the insertion of the Circular Flanged Ring in the spiral-seam tubes comprising most circular and oval HVAC ducting. The method disclosed of making the Circular Flanged Ring enables the use of much thinner gauge steel for the connection of duct section ends and in creating an airtight connection between duct section ends. The Circular Flanged Ring, produced by a spinning process, is more uniformly circular in cross section than are flanges produced from a roll forming or press operation and more readily sealed, without elaborate gaskets. 
     In a further aspect of the present invention, the Flange Ring is made in a two-step process with the mating flange portion being spin formed. The hem section and/or the return flange are separately formed and then butt-welded or otherwise attached to the outer perimeter of the mating flange. In another aspect of the present invention, the Flanged Ring can be manufactured by forming the insertion flange as a singular component and then forming the mating flange, hem section and return flange as the second component, perhaps by roll forming or stamping. The two components can be assembled by welding the inside perimeter of the mating flange to the end edge of the insertion flange. 
     As a further aspect of the present invention, the Flanged Ring can be manufactured by spin forming the mating flange in the manner described above. Thereafter, the hem section can be formed by a roll forming method using roll forming dies. If a return flange is utilized, the hem section and return flange can both be formed from the material stock extending beyond the outer perimeter of the mating flange, through the use of a series of roller sets. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an elevation view of the Circular Flanged Ring. 
         FIG. 1A  is a section of  FIG. 1  showing the cross section or profile of a T24 SMACNA Circular Flanged Ring and effectively the elevation view representative of both Circular and Oval Flanged Rings. 
         FIG. 2  is a detail showing a cross section of the interrelationship of the Circular Flanged Ring inserted into ducting, of the Mating Flanges of opposing Circular Flanged Rings meeting in preparation for connection with Sealant depicted between the Mating Flanges. 
         FIG. 3  depicts circular Flanged Rings inserted into ducting, of the Mating Flanges of opposing Circular Flanged Rings meeting in preparation for connection. 
         FIG. 4  is a detail cross section depicting the connection of the Circular Flanged Ring from insertion flange to ducting and between Mating Flanges by screw means where Sealant is spread between the Mating Flanges. 
         FIG. 5  is an elevation view of a Circular Flanged Ring, as depicted in  FIGS. 1 and 3 , cut along a common diameter in preparation for insertion of SMACNA T24 Linear Segments with the T24 cross section as a step in producing the T24 cross section Oval Flanged Ring. 
         FIG. 5A  is a plan view of an assembled Oval Flanged Ring depicting the connection of the Semicircular Flanged Ring Portions to the SMACNA T24 Linear Segments by means of welding. 
         FIG. 6  is an exploded side view of a Lathe Output Shaft with attached Adapter Plate, Backing Plate and Spinning Die. 
         FIG. 7  is an elevation view of the Adapter Plate Reverse Side. 
         FIG. 7A  is an elevation view of the Adapter Plate Obverse Side. 
         FIG. 8  is an elevation view of the Backing Plate Reverse Side. 
         FIG. 8A  is an elevation view of the Backing Plate Obverse Side. 
         FIG. 9  is an elevation view of the Mounting Surface of a Spinning Die. 
         FIG. 9A  is an elevation view of the Working Surface of a Spinning Die showing the Collar, clamp means and threaded means for mounting purposes. 
         FIG. 9B  is a perspective view of the Spinning Die. 
         FIG. 10  is a perspective view of a Flanged Ring Band Stock Strip of LFQ steel cut to length in preparation for rolling into a band or circular form. 
         FIG. 10A  is a perspective view of a rolled strip of LFQ steel formed into a band shape with Strip First and Second Ends ready to be butt welded together. 
         FIG. 10B  is a perspective view of a Flanged Ring Band Stock which has been butt welded and is ready for insertion into a Spinning Die in preparation for spinning, stretching, forming and trimming into a Circular or Oval Flanged Ring. 
         FIG. 11  is a perspective showing the Flanged Ring Band Stock and the Spinning Die. 
         FIG. 11A  is a side view of a Flanged Ring Band Stock prepared to be inserted and secured in a Spinning Die. 
         FIG. 11B  is a side view of a Flanged Ring Band Stock in the inserted position within a Spinning Die in preparation for machining steps directed to the production of a Circular Flanged Ring. 
         FIG. 11C  is a detail view showing a portion of the Spinning Die including the Collar and Collar components (Collar Strip and Mating Strip), a Flanged Ring Band Stock received by the Collar and into the Working Surface Grove and secured by a Cam Clamp. 
         FIG. 12  is a depiction of an Internal Roller machine tool with the Internal Roller Wheel having ideally about a 1/211 radius configured at 90 degrees to an axis through the Internal Roller Handle First to Second End. 
         FIG. 13  is a depiction of a Radius Roller with the Radius Roller Wheel having ideally about a 1/811 radius configured in line with an axis through the Radius Roller Handle First to Second End. 
         FIG. 14  is a depiction of a Finishing Roller with the Finishing Roller Wheel having ideally about a 1/211 radius configured in line with an axis through the Finishing Roller Handle First to Second End. 
         FIG. 15  is a depiction of a Trim Lever which provides ideally about a 1/211 square×3 1/211 carbide insert Cutting Tip configured in line with an axis through the Trim Lever Handle First to Second End. 
         FIG. 16  is a side view of a Power Lever from which all other machine tools employed herein are operated to obtain leverage for the stretching, forming and trimming operations. Top Surface and Bottom Surface Pins are depicted. 
         FIG. 16A  is a plan view showing the Power Lever Head and Power Lever Top Surface Pin. 
         FIG. 16B  is a bottom view showing the Power Lever Head and Power Lever Bottom Surface Pin. 
         FIG. 17  is a plan view showing a Tool Rest which is affixed to a lathe cradle. The Tool Rest has a plurality of apertures which receive the Power Lever Bottom Surface Pin for positioning and working the machine tools in stretching, forming and trimming the Circular Flanged Ring. 
         FIG. 17A  is a perspective showing the Tool Rest Top and a plurality of apertures which will receive the Power Lever Bottom Surface Pin. 
         FIG. 18  is a partial cross sectional view showing the Flanged Ring Band Stock inserted into a Spinning Die in preparation for the machining steps to produce a Circular Flanged Ring. 
         FIG. 18A  is a partial cross-sectional view showing the results of the first machining step which is to stretch the portion of the Flanged Ring Band Stock which protrudes from the Spinning Die into a Mating Flange. 
         FIG. 18B  is a partial cross-sectional view showing the association of the Follow Block with the Mating Flange and the forming of the Hem. 
         FIG. 18C  is a partial cross-sectional view showing the final step consisting of forming the Return Flange of the Circular Flanged Ring. 
         FIG. 19  is a plan view of a Follow Block comprised of Circular Cut Plywood Pieces ¾″ thick positioned concentrically with a 1″ thick×6″ diameter mild steel Tail Stock Plate having a centrally located Tail Stock Aperture. 
         FIG. 19A  is an elevation of a Follow Block. 
         FIG. 20  is an elevation of the assembly restraining the Flanged Ring Band Stock including the Lathe Output Shaft, the Adapter Plate, the Spinning Die, the Flanged Ring Stock, and the Follow Block; 
         FIG. 21  is a view similar to  FIG. 2  showing an alternative embodiment of the sent invention; 
         FIG. 22  is a view similar to  FIG. 21  showing a further alternative embodiment of present invention; 
         FIGS. 23A ,  23 B,  23 C,  23 D,  23 E, and  23 F illustrate an alternative method of forming the present invention; and 
         FIGS. 24A ,  24 B, and  24 C, and  24 D illustrate a further alternative method of forming the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The disclosure of the present invention is the Flanged Ring profile  1  for Circular and Oval Flanged Rings  10 ,  20 , as depicted in  FIGS. 1 ,  1 A,  2 ,  3 ,  4 , and  5 A and the method for the production of such circular and Oval Flanged Rings. These Flanged Rings may conform to the SMACNA T24 profile. The method of production is depicted in  FIGS. 6 through 19A .  FIGS. 2 ,  3 , and  4  show the Circular and Oval Flanged Rings  10 ,  20  in relationship to Ducting  30  and the connection of opposing Circular Flanged Rings  10 . Other profiles may be produced by this method. 
     The preferred embodiment of making the disclosed Circular Flanged Ring  10  includes the following materials, steps and process: LFQ steel, or other Flanged Ring Band Stock  40  material, is normally receipted in coil form and is decoiled and cut into Flanged Ring Band Stock Strips  41  having Strip First and Second Ends  44 ,  46 , as shown in  FIG. 10  the length of the circumference of the Circular Flanged Ring  10  to be produced (Flanged Ring Band Stock Strips  41  of widths other than 3.875″ may also be used with the width limited by the configuration of the Spinning Die  50  and the dimensions of the desired Circular Flanged Ring  10 ). Each Flanged Ring Band 
     Stock Strip  41  is formed into a band form, which is substantially circular as shown in  FIG. 10A , for ease of affixing the Strip First and Second Ends  44 ,  46  together, for example, by butt welding the Strip First and Second Ends  44 ,  46  together, with the band forming accomplished by means, for example, with a rolling machine including a pyramid rolling machine. The preferred means of connection of the Strip First and Second Ends  44 ,  46  is by butt welding by use of a tungsten inert gas process with no filler. The butt welding forms the Strip First and Second End Weld  48  and concludes the formation of the Flanged Ring Band Stock  40  as shown in  FIG. 10B . It is important, for successful spinning and forming of the circular Flanged Ring  10 , that the butt weld of the Strip First and Second Ends  44 ,  46  not produce a seam. Any seam, ridge, irregularity or any fill in the weld will increase the probability of the seam cracking, as the Flanged Ring Band Stock  40  is stretched in the spinning process, ruining the 
     Flanged Ring. Band Stock  40  and creating a safety hazard. The Flanged Ring Band Stock  40  will be received into and secured into a Spinning Die  60  as shown in  FIGS. 10 ,  10 A and  10 B. 
     The disclosed process requires the Flanged Ring Band Stock  40  to be rotated or spun for forming and trimming. The Flanged Ring Band Stock  40  may be fixed in a die which is in turn rotated or spun for presentation to and work by various machine tools. The rotation of the die means and Flanged Ring Band Stock  40  may be accomplished, for example, by a lathe with either a vertically or a horizontally mounted Lathe Output Shaft  50 . The preferred embodiment, for example, utilizes a lathe with a horizontally mounted Lathe output Shaft  50  to which is mounted, via adaptor and or mounting means, a Spinning Die  60 . 
     The die means may be provided, for example by a Spinning Die  60  shown in  FIGS. 9 ,  9 A, and  9 B, which in the preferred embodiment, consists of a circular Base Plate  61  formed from approximately 1″ thick mild steel plate having a Mounting Surface  62  and a Working Surface  64  and an outside diameter approximately 1″ greater than the outside diameter of the Flanged Ring Band Stock  40  which is selected for forming and trimming. Mounting means is provided which enables the Lathe Output Shaft  50  to be located at the effective center of the Mounting Surface  62 . On the Working Surface  64  of the Base Plate  61  a die means or fixture receives and secures the Flanged Ring Band Stock  40  and may be provided, for example, by a Collar  70  assembled from components consisting of: 1) a Collar Strip  72  consisting of ⅜″ thick×2″ wide mild steel strip which is rolled to a 2″ wide strip in a circular form having an inside diameter approximately 1/16 greater than the outside diameter of the Flanged Ring Band Stock  40  and with the strip width of approximately 2″. The Collar Strip  72  has End Edges  73 ,  74 . The End Edge  74  is tack welded to the Working Surface  64  of the Base Plate  61  so that the Collar  70  and Spinning Die  60  are concentric around the center of the Spinning Die  60 . The interior perimeter of the Collar  70 , between the End Edges  73 ,  74 , forms the Insertion Face  76 ; 2) A Working Surface Groove  66 , 1/16″× 1/16″, is machined into the Working Surface  64  of the Base Plate  61  at the intersection of the Collar Strip End Edge  74  and the Working Surface  64 . The Working Surface Groove  66  has an outside diameter equal to the inside diameter of the Insertion Face  76  and inside diameter ideally about ⅓″ less than the inside diameter of the Insertion Face  76 . The Working Surface Groove  66  accepts the inserted edge of the Flanged Ring Band Stock  40 ; 3) A ½″ thick×1⅜″ wide mild steel Mating Strip  80  in a circular form has a Mating Surface  84 , Mating Strip Bottom  86 , a Mating Surface/Hem Edge  85 , and a Mating Face  82  at the interior perimeter of the Mating Strip  80 . The Mating Strip  80  is flat burned arc with an inside diameter at the Mating Face approximately about 1/16″ greater than the Flanged Ring Band Stock  40  and is tack welded to the Collar Strip End Edge  73  distal from the Working Surface  64  such that the 1⅜″ wide surface of the Mating Surface  84  is parallel to the Working Surface  64 ; 4) the Collar  70  assembly is continuously welded between the Collar Strip End Edge  74  and the Working Surface  64  (Collar Strip Second Edge Weld  78 ) and between the Collar Strip End Edge  73  and the Mating Strip Bottom  86  (Mating Strip Bottom Weld  88 ) via the mig welding process. The Collar  70  or die or fixture means, receiving the Flanged Ring Band Stock  40 , may be provided by means other than described including machining or constructing from a single component or other combinations of components and may have a variety of dimensions depending on the final intended dimensions of the Circular or Oval Flanged Ring  10 ,  20  to be produced. 
     Clamping means, including for example Cam Clamps  90 , as shown in  FIGS. 9A ,  9 B,  11 ,  11 A and  11 B, are affixed to the Working Surface  64  of the Base Plate  61  and positioned to rotate and bind the inserted Flanged Ring Band Stock  40  between the clamp cam and the inner perimeter of the Insertion Face  75  thus securing the Flanged Ring Band Stock  40  between the Cam Clamp  90  and the inner perimeter during the spinning, forming and trimming process. Depending upon the size of the Circular or Oval Flanged Ring  10 ,  20  to be produced, there will be at a minimum of two Cam Clamps  90  for a 14″ diameter Circular Flanged Ring  10  and up to eight or more Cam Clamps  90  for a 60″ diameter Circular Flanged Ring  10 . 
     The Spinning Die  60  means will be balanced and will have material strength sufficient to permit smooth and safe rotation up to and exceeding 3,000 rpm. Machining or other steps may be necessary to help insure that the Spinning Die  60  and all structure means or supporting structural member means are truly round and balanced in all axis in order to minimize vibration. The Spinning Die  60  structure may, for example, include the Spinning Die  60 , a circular Adapter Plate  100  and a circular Backing Plate  110  with means for securing concentrically the Adapter Plate  100  to the Lathe Output Shaft  50  and the Adapter Plate  100  to the Base Plate  61  Mounting Surface  62 . For the production of Circular Flanged Rings 42″ diameter and greater, means for concentrically securing, for structural stability, the Backing Plate  110  between the Adapter Plate  100  and the Spinning Die  60 . The Adapter Plate  100 , for example, may be composed of a ½″ thick circular steel plate 14″ in diameter having an Adapter Plate Obverse and Reverse Side  102 ,  104  and having a fixture means, at the Adapter Plate Reverse Side  104 , for concentric attachment to the Lathe Output Shaft  50  including threaded means which may be, for example, a Hub  107  providing a female thread for mating with a Lathe Output Shaft  50 . The Adapter Plate  100  may, for example, have means for concentric attachment to the Mounting Surface  62  of the Base Plate  61  including Bolt Apertures  109  from the Adapter Plate Reverse to Obverse Sides  104 ,  102  having therein threaded means with the Bolt Apertures  109  symmetrically positioned on a pattern which will be mirrored and matched by Bolt Apertures  109  from the Mounting Surface to the Working Surface  64  of the Base Plate  61 . The additional mass involved in the Spinning Die  60  for Circular Flanged Rings  10  of 42″ diameter and greater may require additional structural stability which may be provided, for example, by the utilization of a Backing Plate  110  comprised of a 1″ thick circular steel plate 42″ in diameter having Backing Plate Obverse and Reverse Sides  111 ,  112  and mounting means for concentrically mating with the Adapter Plate  100  and the Spinning Die  60 . Mounting means for the Backing Plate  110  may include, for example, Bolt Apertures  109  from the Backing Plate Obverse to Reverse Side  111 ,  112  having threaded means therein and symmetrically positioned on a pattern which will be mirrored and matched by Bolt Apertures  109  for the Adapter Plate  100  and the Spinning Die  60 . 
     The Spinning Die  60  is selected in accordance with the diameter of Circular or Oval Flanged Ring  10 ,  20  to be produced and the Spinning Die  60  is mounted, by mounting means, on rotation means including a Lathe Output Shaft  50 . The workpiece in the form of a Flanged Ring Band Stock  40  is inserted in the Spinning Die  60  against and received by the Insertion Face  75  and Mating Face  82  and into the Working Surface Groove  66  where it is secured by means including clamp means provided, for example, by Cam Clamps  90 . The Flanged Ring Band Stock  40  is rotated in preparation for the forming and trimming process. 
     The forming and trimming of the flanged ring involves standard machine tools and stabilizing devices including: 
     1) an Internal Roller  120 , as shown in  FIG. 12 , having an Internal Roller Wheel  122  comprising a wheel having a perimeter consisting of a convex wheel working surface and pivot means attached by means to a Internal Roller Tool Fixture  124  provided, for example, by an Internal Roller Handle  126  permitting the wheel to rotate in a plane 90 degrees to a longitudinal axis from an Internal Roller Handle First and Second Ends  127 ,  128  when the wheel working surface is in contact with the Mating Flange  4  portion of the Flanged Ring Band Stock  40  when clamped into the Spinning Die  60  (the Internal Roller  120  for the preferred embodiment of the disclosed method has a convex working surface with a ½″ radius and the Internal Roller Handle  126  proximal to the Internal Roller Wheel  122  has five ¾″ diameter holes spaced equally 1¼″ apart); 
     2) a Radius Roller  130 , as shown in  FIG. 13 , having a Radius Roller Wheel  132  comprising a wheel having a perimeter consisting of a convex wheel working surface and pivot means attached by means to a Radius Roller Tool Fixture  134  provided, for example, by a Radius Roller Handle  136  permitting the wheel to rotate in a plane parallel to a longitudinal axis from a Radius Roller Handle First and Second Ends  137 ,  138  when the wheel working surface is in contact with the Hem portion  5  of the Flanged Ring Band Stock  40  when clamped into the Spinning Die  60  (The Radius Roller Wheel  132  for the preferred embodiment of the disclosed method has a convex working surface with a ⅛″ radius and the Radius Roller Handle  136  proximal to the Radius Roller Wheel  132  has five ¾″ diameter holes spaced equally 1¼″ apart); 
     3) a Trim Lever  140 , as shown in  FIG. 15 , comprising a Cutting Tip  142  affixed to a Trim Lever Tool Fixture  144  provided, for example, by a Trim Lever Handle  146  permitting the Cutting Tip  142  to extend parallel with a longitudinal axis from the Trim Lever Handle First to Second Ends  147 ,  148  with the Cutting Tip  142  for cutting or trimming the hem  5  as the step preliminary to the production of the return flange  6  (The Cutting Tip  142  for the preferred embodiment of the disclosed method has a 1/211 square×3½″ long carbide cutting tip and the Trim Lever Handle  146  proximal to the Cutting Tip  142  has five ⅜″ diameter holes spaced equally 1¼″ apart); 
     4) a Finishing Roller  150 , as shown in  FIG. 14 , having a Finishing Roller Wheel  152  having a perimeter consisting of a convex wheel working surface and pivot means attached to a Finishing Roller Tool Fixture  154  provided, for example, by a Finishing Roller Handle  156  permitting the Finishing Roller Wheel  152  to rotate in a plane parallel to a longitudinal axis from a Finishing Roller Handle First and Second Ends  157 ,  158  when the wheel working surface is in contact with the Return Flange  6  portion of the Flanged Ring Band Stock  40  when clamped into the Spinning Die  60  (The Finishing Roller Wheel  152  for the preferred embodiment of the disclosed method has a convex working surface with a ½″ radius and the Finishing Roller Handle  156  proximal to the Finishing Roller Wheel  152  has five ¾″ diameter holes spaced equally 1¼ apart). 
     The Internal Roller  120 , Radius Roller  130 , Trim Lever  140  and Finishing Roller  150  are urged against the appropriate portions of the Flanged Ring Band Stock  40  by machining process means, including by manual/hand manipulated means, automated machine tool means operated and controlled by computers and computer programs and other process control systems and other machine tool processes. Leverage, to manually urge the above machine tools in their function may, for example, be facilitated by the following: 
     1) Tool Rest  170 , as shown in  FIG. 17 , which is mounted in a position opposing the rotating Spinning Die  60  at a position where the indicated machine tools may be brought into contact with the Flanged Ring Band Stock  40  and undertake the machining steps described. The Tool Rest  170  may be mounted, for example, on a lathe cradle opposing the Spinning Die  60  within which the various machine tools will operate on the Flanged Ring Band Stock  40 . The Tool Rest  170  consists, in the preferred embodiment, of a mild steel block 37″ long×3″ thick×4″ wide with the Tool Rest Top  172  having 30 apertures sized to receive a ¾″ diameter pin and spaced 1⅛″ apart along the length of the Tool Rest Top  172 ; 
     2) a Power Lever  160 , as shown in  FIGS. 16 ,  16 A and  16 B, comprising a Power Lever Head  161  having a Power Lever Head Top and a Bottom Surface  162 ,  163 , a Top Surface Pin  164  ¾″ diameter×¾″ long extending from the Power Lever Head Top Surface  162  and a Bottom Surface Pin  165  ¾″ diameter×¾″ long extending from the Power Lever Head Bottom Surface  163 . The Top and Bottom Surface Pins  164 ,  165  are ideally parallel to and offset from each other. The Power Lever Head  161  is affixed to a tool fixture provided, for example, by a Power Lever Handle  167 . The Power Lever  160  is used, in the manual/hand production procedure, to provide the pivot point about which the machine tools are operated to attain the leverage required to form, stretch and trim the Flanged Ring and Band Stock  40 . 
     In the preferred embodiment of the method of production by hand, a guide plate means is affixed, following formation of the Mating Flange  4 , to a Lathe Tail Stock  188 , and is bound by friction against the Mating Flange  4  portion of the Flanged Ring Band Stock  40 , thereby securing the Flanged Ring Band Stock  40  between the Mating Surface  84  and e guide plate means. The guide plate means is provided, for example, by a Follow Block  180 , as shown in  FIGS. 19 and 19A , preferably comprised of two Circular Cut Plywood Pieces  182 , each ¾″ thick, secured together to form a 1½″ thick combined plywood piece, having an outside diameter ideally substantially equal to the outside diameter of the Mating Surface  84 . A 1″ thick 6″ diameter mild steel Tail Stock Plate  184  has a centrally positioned Tail Stock Aperture  186 , sized to receive the Lathe Tail Stock  188 , is concentrically affixed by means, for instance bolt means, to the Circular Cut Plywood Pieces  182 . 
     The method disclosed for the production of the Circular Flanged Ring  10  is as follows:
     I. The Adapter Plate  100  is mounted to the Lathe Output Shaft  50 .   II. The Spinning Die  60  (with Backing Plate  110  when the Circular Flanged Ring  10  diameter is 4211 and greater) is mounted to the Adapter Plate  100 .   III. A Flanged Ring Band Stock  40  is inserted into the Spinning Die  60  and secured by clamps, as shown in  FIG. 18 .   IV. A Tool Rest  170  is mounted on a lathe cradle. A Power Lever  160  via a Bottom Surface Pin  165  is inserted into an aperture at the Tool Rest Top  172 .   V. The lathe is powered causing the Spinning Die  60  to revolve.   VI. An Internal Roller  120  is positioned on the Top Surface Pin  164  of the power lever via an aperture in the Internal Roller Handle  126 . The Internal Roller Wheel working surface  122  is positioned on the inside of Flanged Ring Band Stock  40  at the outer 1/16″ of the Flanged Ring Band Stock  40  distal from the Working Surface  62  and causes the portion of the Flanged Ring Band Stock  40  extending past the Mating Face  82  to be stretched and bent against the Mating Surface  84  forming a Mating Flange  4 , as shown in  FIG. 18A . The portion of the Flanged Ring Band Stock  40  received into the Collar  70  and against the Insertion Face  75  is the Insertion Flange  3  forming approximately a 90 degree angle with the Mating Flange  4 , as shown in  FIG. 18A . The portion of the Flanged Ring Band Stock  40  extending from the Mating Flange  4  portion of workpiece distal from the Insertion Flange  3  and toward the portion of the Flanged Ring Band Stock  40  which will include the Hem  5  is bent against the Mating Surface/Hem Edge  85  forming an approximate 20 degree angle between the Hem portion and the Mating Flange  4 , as shown in  FIG. 18A . This concludes the machine tool activity required of the Internal Roller  120 .   VII. Upon conclusion of forming by the Internal Roller  120  a Follow Block  180  is positioned against the Mating Surface  84 . The portion of the Flanged Ring Band Stock  40  distal from the Insertion Flange  3  and Mating Flange  4 , which will form the Hem  5  and the Return Flange  6  extends beyond the Mating Surface  84  and the Follow Block  180  and is accessible to machine tool operations. The Internal Roller  120  is removed from the Power Lever  160  and replaced with a Radius Roller  130 . The Radius Roller Wheel  132  convex working surface is positioned at a 45 degree angle to the Mating Surface  84  and initially is placed in contact with the Follow Block  180  in order to bring the Radius Roller Wheel  132  up to speed. The Radius Roller Wheel  132  is then forced onto the exposed portion of the Flanged Ring Band Stock  40  at the Mating Surface/Hem Edge  85  causing the metal to stretch in contact with and following the contour of the Hem Surface  76  forming, proximal to the Mating Flange  4 , the Hem  5 , as shown in  FIG. 18B . That portion of the Flanged Ring Band Stock  40  most distal from the Insertion Flange  3  forms an approximately 90 degree angle with the Hem  5  and constitutes the portion of the Flanged Ring Band Stock  40  which will be formed into the Return Flange  6 , as shown in  FIG. 18B .   VIII. The Radius Roller  130  is removed from the Power Lever  160  and replaced with the Trim Lever  140 . The Cutting Tip  142  is placed in contact with the outside edge of the portion of the Flanged Ring Band Stock  40  which will  20  form the Return, Flange  6  and cuts away metal sufficient to leave approximately ⅜″ for the Return Flange  6 .   IX. The Trim Lever  140  is removed from the Power Lever  160  and replaced with the Finishing Roller  150 . The right side of the Finishing Roller Wheel  152  is placed in contact with the edge of the Flanged Ring Band Stock  40  most distal from the Insertion Flange  3 , at an approximate 45 degree angle with the Flanged Ring Band Stock  40  which has been trimmed, allowing the Finishing Roller Wheel  152  to be brought up to the speed of the Spinning Die  60 . The Finishing Roller Wheel  152  is urged against the edge of the Flanged Ring Band Stock  40  causing the metal to fold back onto and in contact with the Hem  5  thus forming the Return Flange  6 .   X. The lathe is turned off and the completed Circular Flanged Ring  40  is removed from the Spinning Die  60 . The method disclosed for the production of the Oval Flanged Ring  20  is as follows:
       I. A Circular Flanged Ring  10  is produced and is cut along a diameter producing two Semi-circular Flanged Ring Portions  22 .   II. SMACNA T24 Linear Segments  24  are produced with the SMACNA T24 Flange Profile I by roll forming or other method.   III. The SMACNA T24 Linear Segments  24  are affixed by means, including welding, to the Semi-circular Flanged Ring Portions  22  to form the Oval Flanged Ring as shown in  FIGS. 5 and 5A .   
       

       FIG. 21  illustrates an alternative to the foregoing described method for producing flanged ring  10 ′. In the alternative method, the mating flange  4 ′ can be produced as described above, and then the outer perimeter of the mating flange trimmed to provide a desired maximum diameter. Thereafter the hem  5 ′ and the return flange  6 ′ can be formed as a separate component by various methods, such as bending flat stock over on itself and then rolling the flat stock into a circular ring. The ends of the rolled, bent-over flat stock could be butt welded together, and then welded to the outer perimeter of the flange  4 ′. 
     The hem  5  and flange  6  could instead be formed by a stamping process beginning with a flat, annular workpiece. Thereafter, the formed hem and flange could be welded to the outer perimeter of the mating flange  4 ′. Producing the hem  5 ′ and return flange  6 ′ as a separate component and then attaching such component to the outer perimeter of the mating flange  4 ′ may not be as efficient as spin-forming the entire flange ring  10 ′ as described above with respect to flange ring  10 . Also, this “2-step” method may result in a certain amount of distortion when the formed hem  5 ′/flange  6 ′ is welded to the mating flange  4 ′. Nonetheless, the 2-step method may be carried out with less sophisticated tooling than required by the spinning method described above. 
     As a further alternative, it is possible to produce the flanged Ring  10 ″ shown in  FIG. 22  by forming the insertion flange  3 ″ as one component and the mating flange  4 ″, hem  5 ″ and return flange  6 ″ as a second component. The insertion flange  3  can be produced as shown in  FIGS. 10–10B  and as described above. The mating flange  4 ″, hem  5 ″ and return flange  6 ″ could be produced by roll-forming or perhaps by stamping. Thereafter, the two components can be assembled by welding the inside perimeter of the mating flange to the end edge of the insertion flange. This alternative technique may suffer from the same disadvantages of the technique shown in  FIG. 21  above, including a larger number of manufacturing steps as well as significant distortion or warpage of the flanged Ring  10 ″ due to the welding operation. On the other hand, it may be possible to produce the flanged Ring  10 ″ using less sophisticated tooling than used to produce the flanged Ring  10 , as described above. 
       FIGS. 23A ,  23 B,  23 C,  23 D,  23 E, and  23 F illustrate an alternative to the foregoing described methods for producing a flanged ring  10 ′″. In this alternative method, a mating flange  4 ′″ can be spin formed as described above. Thereafter, the hem section  5 ′″ can be formed by a first roller set  200  consisting of a first roller assembly  202  composed of a major diameter roller  204  and a side-by-side smaller diameter roller  206 , both mounted on a rotatable shaft  208 . The first roller set  200  also includes a second roller assembly  210  consisting of a roller  212  mounted on a rotatable shaft  214 . The rotatable roller shafts  208  and  214  may be moved towards and away from each other in a substantially parallel orientation in a well-known manner. When the shafts are moved toward each other, the roller  212 , positioned at the side of roller  204 , forms the hem section  5 ′″ by capturing such hem section between the adjacent face sections of the rollers  204  and  212 . In addition, a precursor to the return flange  6 ′″ is formed between the outer diameter of roller  212  and the outer diameter of roller  206 . See  FIG. 23B  wherein the hem section  5 ′″ extends substantially perpendicular to mating flange  4 ′″ and the precursor to the return flange  6 ′″ extends substantially perpendicular to the adjacent end of the hem section. 
     The partially formed Flanged Ring  10 ′″ of  FIG. 23B  is placed in a roller set  220  of  FIG. 23C  for further processing. The roller set  220  includes a die roller assembly  222  composed of a die roller  224  mounted on a rotatable shaft  226 . The die roller  224  has a groove formed around its outer perimeter in the shape of a half “V” composed of a vertical face  228  and a diagonal face  230 . The roller set  222  also includes a second roller assembly  232  composed of a cylindrical roller  234  mounted on a rotatable shaft  236 . The roller assemblies  224  and  232  are capable of moving towards and away from each other while the rotatable shafts  226  and  236  remain substantially parallel to each other. As shown in  FIG. 23C , the partially formed Flanged Ring  10 ′″ from  FIG. 23B  is positioned relative to roller  224  so that hem section  5 ′″ is adjacent vertical face  228  of roller  224 . Thereafter, the roller sets  222  and  232  are moved towards each other as the rollers  224  and  234  rotate relative to each other thereby causing the return flange section  6 ′″ to assume the orientation of roller face  230  relative to roller face  228 , as shown in  FIG. 23D . 
     Thereafter, the flanged ring in the configuration of  FIG. 23D  is further formed by roller set  240  shown in  FIG. 23E . Roller set  240  consists of a pair of roller assemblies  242  and  244  each composed of a roller  246  and  248  carried by a corresponding rotatable shaft  250  and  252 . As shown in  FIG. 23E , the hem section  5 ′″ and the partially formed return flange  6 ′″ are placed between the two rollers  246  and  248  and then the two rollers are moved relatively towards each other while rotating, thereby to pinch the hem section and return flange therebetween so that the return flange closely overlies the hem section and thereby completing the formation of the flanged ring  10 ′″, as shown in  FIG. 23F . 
       FIGS. 24A ,  24 B,  24 C, and  24 D illustrate another method of forming a flanged ring  10 ′″ in accordance with the present invention. As illustrated, the mating flange  4 ″″ of the flanged ring  10 ′″ is formed using a spin forming method, such as described above. Thereafter, the outer marginal portion of the mating flange is placed in roller set  300  to partially form hem section  5 ″″ and return flange  6 ″″, as shown in  FIG. 24B . The roller set  300  includes a first roller assembly  302  consisting of a roller die  304  mounted on the rotatable shaft  306 . A “V” shaped groove  308  extends around the circumference of the roller die  304  to match the outer perimeter profile of a roller die  310  mounted on rotatable shaft  312  of a roller assembly  314 . The roller assemblies  302  and  314  are capable of moving towards and away from each other while their respective shafts  306  and  302  rotate and maintain an orientation substantially parallel to each other. As a consequence, when the outer marginal portion of the mating flange  4 ″″ is placed in alignment with groove  308  and then the roller dies  304  and  310  rollably engage with each other they cooperatively form hem section  5 ″″ and return flange  6 ″″ in the orientation shown in  FIG. 24B . 
     Thereafter, the partially formed flanged ring shown in  FIG. 24B  is further worked by roller set  340  shown in  FIG. 24C . The roller set  340  corresponds to the roller set  240  shown in  FIG. 23E , with the description set forth above with respect to  FIG. 23E  applying to  FIG. 24C , but with the part numbers increased by 100. Thus, such description will not be repeated. The result of roller set  340  is a finished flanged ring  10 ″″ as shown in  FIG. 24D . 
     It will be appreciated that other combinations of roller sets could be utilized to form the hem section and return flange of the flanged ring, other than as illustrated above in  FIGS. 23 and 24 . Although use of such rolling techniques may not be as efficient as spin forming the entire flange ring in the manner described above, utilizing rolling processes may enable the flange ring to be manufactured with less expensive tooling or with tooling already on hand as opposed to requiring extensive spin form tooling.