Abstract:
The invention is directed to apparatus and a method of using the apparatus to draw a blank into a product. The apparatus includes a die having a cavity to receive the blank being drawn into the product, a clamp adapted to apply an adjustable force against the blank during the drawing operation, and a mandrel comprising a plurality of nested tool segments, the tool segments independently extendable to engage and draw different portions of the blank into the desired product within the cavity.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention is directed to a method and apparatus for deep drawing a metal blank to form a finished product, and in particular, it is directed to forming a one-piece finished product by moving material from the product bottom portion and into the product sidewall portion during the deep drawing operation.  
         BACKGROUND OF THE INVENTION  
         [0002]    Various methods and tooling arrangements have been used in the past to deep-draw and/or iron a metal blank into a one-piece finished product, for example but not limited to, containers for holding food and beverage products as well as non-eatable products, automotive parts such as oil filters, air conditioner accumulators and charcoal canisters, and Bob can you add additional products?. . . Such past apparatus and methods are shown in the patents listed in the information disclosure statement filed with the present patent application. For instance, U.S. Pat. No. 5,209,099, granted to Saunders on May 11, 1993, discloses typical state-of-the-art can forming methods and apparatus comprising a die, a clamp, and a draw punch arrangement used in combination to form a metal blank into a one-piece container; the formed one-piece container having an open end that receives a lid in a downstream manufacturing step. Saunders teaches clamping the cut metal blank against the surface of the die while the draw punch is extended to force portions of the metal blank into the die cavity. In such a deep drawing operation, the draw punch typically approximates the desired size and/or shape of the finished product bottom, and the punch first forces the corresponding bottom portion of the metal blank into the die cavity with little or no working while the sidewall portions of the blank are worked within the die cavity to form the sidewall of the one-piece finished product. As a result of such unequal working along different portions of the metal blank, the finished product has a bottom thickness that is relatively close to the original metal blank thickness, and the product sidewall is greatly reduced in thickness when compared to the original blank thickness.  
           [0003]    Although such manufacturing process produce a one-piece product that is functionally sound from a user viewpoint, the drawing processes of the past are wasteful from a manufacturing viewpoint in that past methods fail to use excess bottom material during the manufacturing process. Therefore, recognizing this, the present invention is directed to providing a method and apparatus that more efficiently uses the excess bottom material by moving excess metal from the product bottom portion and into the product sidewall.  
         SUMMARY OF THE INVENTION  
         [0004]    It is therefore an object of the present invention to provide a method and apparatus for improving the use of available product blank material during a deep drawing operation.  
           [0005]    It is another object of the present invention to provide a method and apparatus that moves excess material in a product bottom to the product sidewalls during a deep drawing operation.  
           [0006]    It is still another object of the present invention to form a deep-drawn product from a smaller product blank when compared with past product blanks for the same product by moving excess material from the product bottom to the product sidewalls during a deep drawing operation.  
           [0007]    Other objects and advantages of the present invention will become apparent as a description thereof proceeds.  
           [0008]    In satisfaction of the foregoing objects and advantages, the present invention provides apparatus, and a method of using the apparatus, to draw a blank into a product. The apparatus includes a die having a cavity to receive the blank being drawn into the product, a clamp adapted to apply an adjustable force against the blank during the drawing operation, and a mandrel comprising a plurality of nested tool segments, the tool segments independently extendable to engage and draw different portions of the blank into the desired product within the cavity.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The above and other objects and advantages and novel features of the present invention will become apparent from the following detailed description of the preferred embodiment of the invention illustrated in the accompanying drawings, wherein:  
         [0010]    Figs.  1 A- 1 C show apparatus used in the past to deep-draw a metal blank to a formed one-piece product. FIGS.  2  shows various portions of a product blank relative to a corresponding one-piece product. FIGS.  3 A- 3 F show the apparatus of the present invention used to deep-draw a metal blank to a formed one-piece product. FIGS.  4 A- 4 E show an alternate embodiment of the present invention used to deep-draw a metal blank to a formed one-piece product. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0011]    Prior Art  
         [0012]    Referring to Figs.  1 A- 1 C labeled Prior Art, and FIG. 2, past apparatus for manufacturing a one piece deep-drawn product  6  typically comprises, in its simplest form, a die  1 , a die cavity  2  in which the desired one-piece deep-drawn product is formed, a clamp  3  for holding the product blank  4  against a surface of the die, and a mandrel or draw punch  5  used to force portions of the product blank  4  into the die cavity  2  during the drawing and/or ironing operation that forms the desired one-piece finished product  6 . As shown in FIG. 1A, the product blank is positioned over the die cavity opening  7  and clamp  3  exerts a calculated force  8  that slidably clamps the product blank  4  to a surface  9  of the die adjacent the die cavity opening  7 . The clamping force  8  is calculated so that when mandrel  5  is extended to force the product blank into the die cavity  2  during the drawing and/or ironing operation, the product blank portion that is slidably clamped between the die  1  and clamp  3 , slides between the two surfaces to provide a controlled feed of blank material into die cavity  2  during the drawing operation.  
         [0013]    Referring in particular to FIG. 2, a product blank  4  is cut to provide sufficient blank material for forming the desired deep-drawn product. Such product blanks comprise a bottom portion “B” that provides material to form the desired product bottom, a side portion “S” that provides material to form the desired product sidewall, and a rim portion “R” that remains clamped between the die surface  9  and clamp  3  during the entire drawing and/or ironing operation. Typically, the rim portion “R” is further processed by attaching a lid, or portion R is shaped to provide a lip or rolled edge that eliminates sharp edges.  
         [0014]    As shown in FIG. 1B, mandrel  5  is extended to engage the bottom portion B of blank  4  and the inward moving mandrel forces portion B into the die cavity  2  with little or no working of the bottom portion B. As mandrel  5  travels deeper within cavity  2 , its inward movement causes the sidewall portion S of blank  4  to be drawn into the die cavity  2  where portion S is reduced in thickness and elongated as it is worked between the die and mandrel surfaces. Referring to Fig. 1C, as the mandrel moves to its fully extended position within die cavity  2 , the sidewall portion S is continuously worked to form a one-piece deep-drawn product having a target sidewall thickness. As clearly illustrated by the product blank positions labeled D, D 1 , and D 2  in FIG. 1A- 1 C, as mandrel  5  is moved to its fully extended position within die cavity  2 , the blank portions slideably clamped between die surface  9  and clamp  3  follow mandrel  5  into the die cavity where the blank portion S is formed into the sidewall of the product. Blank  4  is cut so that when mandrel  5  reaches its fully extended position, blank portion R is still clamped against an outside surface of the die. Such past deep-drawing operations produce a one-piece product having a bottom thickness that approximates the original thickness of blank  4 , and a sidewall having a thickness reduced to about Bob ? % of the original blank thickness. As a result of little or no working along portion B of the blank, past deep-drawing operations waste stock material during the manufacturing process.  
         [0015]    Present Invention  
         [0016]    Referring to FIGS.  3 A- 3 F the preferred embodiment of the present invention, the deep-drawing apparatus comprises a die  11 , a die cavity  12  in which the desired one-piece deep-drawn product is formed, a clamp  13  for holding the product blank  14  against a surface of the die, and a segmented mandrel  15  having a first tool segment  16  slideably captured within a second tool segment  17 ; the first tool segment  16  and the second tool segment  17  being independently extendable or retractable with respect to each other. In the preferred embodiment shown in Figs.  1 A- 1 F, first tool segment  16  and the second tool segment  17  are in coaxial alignment. However, as illustrated in FIGS.  4 A- 4 D, it should be understood that mandrel  15  may comprise a plurality of tool segments that are extendable or retractable along different axis and that the shape of the various tool segments may be either round or non-round.  
         [0017]    Referring again to FIG. 3A, in the preferred embodiment of the present invention, clamp  13  exerts a force  18  that fixes blank  14  against surface  19  of die  11 . Blank  14  is positioned on surface  19  so that the bottom portion B of the product blank is located over the die cavity  12  with the edge of the blank portion R located at a position D on the die surface that is dependent upon the size and shape of the blank required to manufacture the product. The first tool segment  16  is extended to engage and force a surface area of portion B into the die cavity  12  while portions S and R are fixedly clamped against surface  19  of die  11 . Referring to FIG. 3B, the force exerted by tool segment  16  works portion B to provide local thickness reduction as metal moves outward from the worked surface area and toward the walls of the die cavity. The stroke length of tool segment  16  is predetermined so that when it reaches a fully extended position, the worked surface area along portion B is reduced to a desired thickness for the product bottom.  
         [0018]    Mandrel  15  is sequentially operated so that the second tool segment  17  is activated to extend along the first tool segment  16  after tool segment  16  is set into motion, and the second tool segment  17  may be activated while tool segment  16  is working material along the product bottom, or after tool segment  16  has reached its fully extended position. In any event, as clearly shown in FIG. 3C, tool segment  17  extends along tool segment  16  to engage portion B proximate and outward from the surface area worked by tool segment  16 . Because portions S and R of blank  14  remain fixed against die surface  19 , as illustrated at position D, the force exerted by tool segment  17  against blank  14  reduces the product bottom thickness by working the remaining excess material outward from the tool segment and toward the wall of die cavity  12  where the excess material becomes part of the product sidewall as shown in FIG. 3D.  
         [0019]    Referring now to FIG. 3E, after the second tool segment  17  has reached an extended position where the product bottom is worked to a substantially uniform desired thickness, force  18  is reduced so that blank  14  is slideably clamped between surface  19  and clamp  13 . As illustrated by the different position Dl, the moving tool segment  17  of mandrel  15  drags, or forces, the slideably clamped blank  14  into die cavity  12  where portion S of the product blank is worked between the die cavity wall and tool segment  17  to form a product sidewall having a desired wall thickness. It should be noted, however, that although the drawings for the preferred embodiment show the second tool segment  17  extending outward from the first tool segment  16  as the product sidewall is formed, tool segment  16  may follow the extending tool segment  17  through its full sidewall forming stroke without departing from the scope of this invention.  
         [0020]    Referring to FIG. 3F, as the second tool segment  17  moves to its fully extended position within die cavity  12 , the sidewall portion S is continuously worked to form a one-piece deep-drawn product having a target sidewall thickness. As clearly illustrated by the different product blank positions labeled D, D 1 , and D 2  in Figs.  1 A- 1 C, as the second tool segment  17  is moved to its fully extended position within die cavity  12 , the blank portions slideably clamped between die surface  19  and clamp  13  follow the second tool segment  17  into the die cavity where the blank portion S is formed into the sidewall of the product. As in the past, blank  14  is cut so that when the second tool segment  17  of mandrel  15  reaches its fully extended position, blank portion R is still clamped against surface  19  of the die. Because the segmented mandrel  15  of the present invention provides means for working portion B of the blank to form a thinner product bottom, a desired deep-drawn product manufactured with present invention has a smaller and/or thinner product blank when compared to product blank for the same desired product manufactured with prior teaching.  
         [0021]    Referring to FIGS.  4 A- 4 E, as heretofore mentioned, the present invention is not limited to a segmented mandrel having coaxial or circular tool segments. For instance, FIG. 4A discloses a deep-drawing apparatus having a die  21 , a die cavity  22  in which the desired one-piece deep-drawn product is formed, a clamp  23  for holding the product blank  24  against a surface of the die, and a segmented mandrel  25  having a first tool segment  26  slideably captured within a second tool segment  27  that is slideably captured within a third tool segment  30 ; the tool segments,  26 ,  27 , and  30  being independently extendable or retractable with respect to each other. Mandrel  25  is sequentially operated so that the second tool segment  27  is activated to extend along the first tool segment  26  after tool segment  26  is set into motion, and the second tool segment  27  may be activated while tool segment  26  is working material along the product bottom, or after tool segment  26  has reached its fully extended position. In any event, as clearly shown in FIG. 4C, tool segment  27  extends along tool segment  26  to engage a second surface area of portion B proximate and outward from the surface area worked by tool segment  16 . Because portions S and R of blank  24  remain fixed against die surface  29 , as illustrated by position D, the force exerted by tool segment  27  against blank  24  reduces the product bottom thickness by further working excess bottom material outward from the tool segment and toward the wall of die cavity  22 . Clamp  23  exerts a force  28  that fixes blank  24  against surface  29  of die  21 . Blank  24  is positioned on surface  29  so that the bottom portion B of the product blank is located over the die cavity  22  with the edge of the blank portion R located at a position D on the die surface that is dependent upon the size and shape of the blank required to manufacture the product. As shown in FIG. 4B, the first tool segment  26  is extended to engage and force a surface area of portion B into the die cavity  22  while portions S and R are fixed against surface  29  of die  21 . The force exerted by tool segment  26  works portion B to provide local thickness reduction as metal moves outward from the worked surface area and toward the walls of the die cavity. The stroke length of tool segment  26  is predetermined so that when it reaches a fully extended position, the worked surface area of portion B is reduced to a desired thickness for the product bottom.  
         [0022]    Mandrel  25  is sequentially operated so that the second tool segment  27  is activated to extend along the first tool segment  26  after tool segment  26  is set into motion, and the second tool segment  27  may be activated while tool segment  26  is working material along the product bottom, or after tool segment  26  has reached its fully extended position. In any event, as clearly shown in FIG. 4C, tool segment  27  extends along tool segment  26  to engage a second surface area of portion B proximate and outward from the surface area worked by tool segment  26 . Because portions S and R of blank  24  remain fixed against die surface  29 , as illustrated by position D, the force exerted by tool segment  27  against blank  24  reduces the product bottom thickness by further working excess bottom material outward from the tool segment and toward the wall of die cavity  22 .  
         [0023]    Referring now to FIG. 4D, mandrel  25  continues to be sequentially operated so that the third tool segment  37  is activated to extend along the second tool segment  27  after tool segment  27  is set into motion, and the third tool segment  30  may be activated while both tool segments  26  and  27  are working material along the product bottom portion B, or after either one of the tool segments  26  or  27  have reached its fully extended position. In any event, as clearly shown in the drawing, tool segment  30  extends along tool segment  27  to engage a third surface area of portion B proximate and outward from the surface area worked by tool segments  26  and  27 . Because portions S and R of blank  24  continue to be fixed against die surface  29 , as illustrated by position D, the force exerted by tool segment  30  against blank  24  reduces the product bottom thickness by working remaining excess bottom material outward from the tool segment and toward the wall of die cavity  22  where the excess material becomes part of the product sidewall as shown in FIG. 4D.  
         [0024]    Referring now to FIG. 4E, after the third tool segment  30  has reached an extended position where the product bottom is worked to a substantially uniform desired thickness, force  28  is reduced so that blank  24  is slideably clamped between surface  29  and clamp  23 . As illustrated by the different position D 3 , the moving tool segment  30  of segmented mandrel  25  drags, or forces, the slideably clamped blank  24  into die cavity  22  where portion S of the product blank is worked between the die cavity wall and tool segment  30  to form a product sidewall having a desired wall thickness. As the third tool segment  30  moves to its fully extended position within die cavity  22 , the sidewall portion S is continuously worked to form a one-piece deep-drawn product having a target sidewall thickness. As clearly illustrated by the different product blank positions labeled D and D 3  in FIGS.  4 A- 4 E, as the third tool segment  30  is moved to its fully extended position within die cavity  22 , the blank portions slideably clamped between die surface  29  and clamp  23  follow the third tool segment  30  into the die cavity where the blank portion S is formed into the sidewall of the product. As in the past, blank  24  is cut so that when the third tool segment  30  of mandrel  25  reaches its fully extended position, blank portion R is still clamped against surface  29  of the die. Because the segmented mandrel  25  of the present invention provides means for working portion B of the blank to form a thinner product bottom, a desired deep-drawn product manufactured with present invention has a smaller and/or thinner product blank when compared to product blank for the same desired product manufactured with prior teaching.  
         [0025]    While this invention has been described as having a preferred design, it is understood that the invention is capable of further modifications, uses, and/or adaptations which follow in general the principal of the present invention and includes such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and that may be applied to the central features here and before set forth and fall within the scope of the limits of the appended claims.