Abstract:
A punch for forming opposite ends of a copper tube into a T includes a tapered or shovel-nose such that the spacing between the ends of the opposed punches is reduced, thereby reducing the excess copper remaining in the T once formed. A method of forming the fitting employs the shovel-nose punches in a hydro-forming process to accommodate such results.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119(e) and the benefit of U.S. Provisional Application No. 61/243,563 entitled T-FITTING MANUFACTURING METHOD AND TOOL, filed on Sep. 18, 2009, by John W. Schlabach, the entire disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to the manufacturing of copper T-fittings. 
       FIG. 1  shows a diagram of prior art T-fittings manufactured by a hydro-forming process utilizing generally cylindrical end punches, as seen in the prior art manufacturing equipment of  FIG. 12 . The punches move toward one another and engage a copper tube to compress the copper tube to form the orthogonal T-extension. The process includes the subsequent steps of cutting the end of the extending orthogonal section and sizing all three openings of the T for final dimensioning. With prior art processes and tooling, however, a relatively large amount of copper remains in the T at a position opposite the opening of the orthogonal T, as shown by arrow C in  FIG. 1 . In view of the increasing cost of copper, this material, which does not provide a useful function to the T itself, is an unnecessary cost to the final product. 
     There exists a need, therefore, for a T-fitting design and manufacturing process in which the unnecessary material is eliminated while still employing the hydro-forming process. 
     SUMMARY OF THE INVENTION 
     The present invention reduces the amount of copper in a T-fitting by from 10% to 12% by providing a punch for forming opposite ends of a copper tube into a T, which includes a tapered or shovel-nose such that the spacing between the ends of the opposed punches is reduced, thereby reducing the excess copper remaining in the T once formed. The invention involves both a method of forming the fitting employing the shovel-nose punches in a hydro-forming process, the shape of the punch nose to accommodate such results, and the resultant fitting. 
     These and other features, objects and advantages of the present invention will become apparent upon reading the following description thereof together with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a conventional T-fitting manufactured according to the prior art; 
         FIG. 2  is an improved T-fitting manufactured according to the present invention utilizing the tooling of the present invention; 
         FIG. 3  is a left end view of the fitting shown in  FIG. 2 ; 
         FIG. 4  is a perspective view of one of the punch noses employed for compressing opposite ends of a copper pipe to form the T-fitting shown in  FIGS. 2 and 3 ; 
         FIG. 5  is a cross-sectional view of the punch nose; 
         FIG. 6  is a bottom view of the punch nose; 
         FIG. 7  is a front elevational view of the punch nose; 
         FIG. 8  is a top view of the punch nose; 
         FIG. 9  is a side elevational view, partly in phantom, of the punch nose; 
         FIG. 10  is an exploded fragmentary view taken in the circled area X in  FIG. 9 ; 
         FIG. 11  is a right end elevational view of the punch nose; and 
         FIG. 12  is a schematic view of the prior art hydro-forming press. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to  FIG. 1 , there is shown a conventional T-fitting  10  in which a copper tube is formed by compressing under water at high pressure (about 10,000 psi) utilizing cylindrical punch noses compressing a straight section of cylindrical copper pipe in opposite directions indicated by arrows A and B in  FIGS. 1 and 2 . The result is a domed cylindrical orthogonal T-extension  14  ( FIG. 12 ) to the otherwise cylindrical pipe  12 . The enclosed end of domed extension  14  is cut in a second step, after which each of the three open ends is sized in a sizing guide to form the finished product. The cylindrical punches are inserted in the pipe in opposite directions as indicated by arrows A and B, however, resulting in a buildup of copper in the area indicated by arrow C in  FIG. 1 . This extends substantially the width of the of the diameter of the T-section  14 . This buildup of copper material provides no additional strength or functional value to the T-fitting  10  and represents a waste of material. 
     In order to reduce the excess material in area C ( FIG. 1 ), a new fitting  20  has been devised utilizing improved punch noses shown in  FIGS. 4-11 . In fitting  20 , a straight cylindrical section of copper tube  22  is again formed into a T by utilizing the shovel-nose punches  50  of the configuration shown in  FIGS. 4-11  in the hydro-forming equipment of  FIG. 12  instead of the standard cylindrical prior art punch noses. The process takes place in a hydro-forming machine at a high pressure of about 10,000 psi. The utilization of the shovel or tapered punches results in a much smaller buildup of copper in the area shown by arrow D in  FIG. 2 , which results in a 10% to 12% copper savings for the T-fitting  20  as compared to the T-fitting  10  for a given diameter fitting. 
     The method of manufacturing “T”  20  involves three steps, the first step being placing a copper tube of a diameter ⅛″ to about 4″ and having a length slightly longer than the desired final length of the T in a pair of dies in a hydro-forming machine. The lower die is semi-cylindrical and an upper die has the same shape but has a cylindrical opening to allow the projection  24  of fitting  20  to extend through the top die. Punches  50  are pushed in opposite ends to force the ductile copper (which is from 95% to 99% pure) through the opening in the upper die forming an extension  14  which, after the first step, is capped with a copper dome. The partially formed T is then removed from the hydro-forming press, which can be a press that is commercially available from Schuler, such as shown in  FIG. 12 , and placed in a second die, which provides an alignment slot and chisel-like knife for slicing the domed end of projection  24  off, forming the open end  25  of the T, which also includes open ends  21  and  23 , as seen in  FIGS. 2 and 3 . Finally, a finishing step is provided by placing the T-fitting  20  in a final die with three punches entering each of the openings  21 ,  23 , and  25  to provide the final sizing and dimensions for receiving corresponding pipes in a plumbing system. 
     As can be seen by comparing  FIGS. 1 and 2 , a significant percentage of copper is saved by reducing the amount of copper shown by arrow C in  FIG. 1  to a significantly smaller amount, as shown by arrow D in  FIG. 2 . The reduction in the amount of copper in that particular area can be as much as 300% or more and represents an overall copper savings for the T-fitting of from 10% to 12%. The ability to manufacture fitting  20  as shown in  FIGS. 2 and 3  is achieved by the shape of the shovel-nose punch  50  shown in  FIGS. 4-11 . One such punch is used at each of the open ends  21  and  23  ( FIG. 2 ) by the hydro-forming machine  30  ( FIG. 12 ). 
     Punch  50  includes a first end  52  which is coupled to a source of pressurized fluid, such as water, at a pressure of 10,000 pounds or the like and has a generally cylindrical body  54  terminating in a shovel-nosed end  56 . A cylindrical longitudinally extending passageway  55  allows water to pressurize the internal volume of the copper pipe placed in the hydro-forming press. The end  56  includes a lower tapered lip  58  (tapered at about 45°) extending forwardly and concavely curved through an arc of approximately 120°. Lip  58  is tapered upwardly to the opening  55  by a tapered conical transition zone  57  and lead-in zone  59 . Zone  57  circumscribes an arc of about 82° ( FIG. 5 ). The top  51  of the shovel-nose punch is also tapered at  61  at about 45° to form a semi-conical surface. 
     The hydro-forming machine uses two identical punches  50  with one on each end and the shovel-nosed ends  58  align with the lower section  27  ( FIG. 2 ) of the fitting  20  during the forming process, such that the edges  58  of the punch form the edges  26  and  28  of the copper shown by arrow D in  FIG. 2 . By providing an outwardly projecting nose  56  and the angled end defined by side walls  63  and  65  terminating in the upper annular end  51  ( FIGS. 4 ,  7 , and  8 ) allows the shovel-nose design of punch  50  when used in a hydro-forming process to form the fitting shown in  FIGS. 2 and 3  with a reduced amount of excess copper, thereby greatly reducing the cost of the fitting itself and yet providing the same high quality T-fitting available with the prior art processes. The dimensions of the punch  50  are proportionally varied depending on the size of T-fitting  20  being manufactured, although the shovel-nose shape remains substantially as shown. 
     It will become apparent to those skilled in the art that the exact shape of the punch nose may be varied, as will the dimensions for different size T-fittings, without departing from the spirit or scope of the invention as defined by the appended claims.