Abstract:
An adjustable die set and method for forming corrugations in a sheet in which pairs of elongated forming bars are detachably mounted parallel to each other in respective holders driven by upper and lower press members. One pair is more closely spaced than the other and moves between the forming bars of the other pair to form a corrugation. The spacing and depth of the bar is varied to produce corresponding varying configurations of the corrugations.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. provisional application Ser. No. 60/866,107 filed on Nov. 16, 2006. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to tooling and methods for forming corrugations into sheet metal. 
         [0003]    Corrugations are formed into metal sheets in order to strengthen the same against bending loads for such uses as floor panels subjected to heavy loads. 
         [0004]    The use of conventional die sets can be used where the production volume of a given corrugated panel is sufficient to justify the cost of the die set which is typically quite high. 
         [0005]    Another method is to form a series of bends in the sheet using standard forming tools, but this is very time consuming as four separate bending operations are required for each corrugation and this process also requires turning over the sheet or plate for each bend. 
         [0006]    While adjustable tooling for forming parts has been proposed in the past, such as shown in U.S. Pat. Nos. 2,440,809 and 6,834,525, these have not been suitable for forming heavy duty corrugated sheet for such applications as panels used for the bottom of cargo barges, trucks, and the like. 
         [0007]    It is the object of the present invention to provide an adjustable die set and method for forming corrugations in relatively thick sheet metal with a single press operation to enable a number of varying corrugation configurations to be formed with a single low cost die set. 
       SUMMARY OF THE INVENTION 
       [0008]    The above recited object and other objects which will be understood upon a reading of the following specification and claims are achieved by a die set including an upper and lower die each constructed of individual components which can be assembled in different ways or with components of different dimensions to create different corrugation configurations in a forming press. 
         [0009]    The individual components themselves can be made at low cost and of varied dimensions to enable formation of a great number of corrugation configurations by assembling the components in alternative ways. 
         [0010]    The individual die components each comprise a pair of die forming bars having a radiused or rounded shoulder on one or more corners. The die forming bars are mounted assembled on edge to a holder with one or more interposed spacers to be spaced apart and parallel to each other with the rounded shoulders located opposite each other in one die but away from each other in another die, both pairs of forming bars spaced a part a distance corresponding to a given corrugation dimension desired. The two pairs of die bars are spaced apart at different distances to create a clearance allowing one pair of forming bars to move between the other forming bar pair, and thus produces inclined corrugation sidewalls extending between the rounded corners of a forming bar in one pair to the rounded corner on the other adjacent forming bar of the other pair without any contact with the inclined corrugation sides. 
         [0011]    In the upper die, a block may comprise a spacer while in the lower die a U-shaped holder may be used allowing the upper die set forming bar pair to enter a space between the lower die set forming bar pair. 
         [0012]    This arrangement allows a great number of corrugation configurations to be formed in a single press cycle, with the relative width of the upper die pair set and lower die forming bar pair producing a given inclination of the formed corrugation side walls, as the relative width of the flattened bottom varies with the relative spacings of the sets of upper and lower die forming bar pairs. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is an end view of an adjustable die set according to the present invention installed on press upper and lower ram members with a section of sheet material disposed the die set and having a corrugation formed therein by operation of the press. 
           [0014]      FIG. 1A  is an end view of the die set shown in  FIG. 1  with an unformed sheet section disposed therein prior to a forming operation of the press. 
           [0015]      FIG. 1B  is an end view of the die set shown in  FIG. 1  with the upper and lower dies advanced together by the press operation to form a corrugation in a sheet disposed in the die set. 
           [0016]      FIG. 2  is a side view of the upper die shown in  FIG. 1 . 
           [0017]      FIG. 3  is an end view of a second arrangement of individual components of the upper and lower dies and a section of sheet material disposed therein and having a different corrugation configuration formed therein. 
           [0018]      FIG. 4  is an end view of a third arrangement of individual components of the upper and lower dies and a sheet section disposed therein having another corrugation configuration formed therein. 
           [0019]      FIG. 5  is an end view of a lower die showing an assembly of spacers thereon. 
           [0020]      FIG. 6  is an end view of a lower die with a variation of the assembly of spacers thereon. 
           [0021]      FIG. 7  is a side view of the lower die shown in  FIGS. 5 and 6 . 
           [0022]      FIG. 8  is an end view of an alternative shape of a die bar. 
           [0023]      FIG. 9  is an end view of an alternative shape of a die bar. 
       
    
    
     DETAILED DESCRIPTION  
       [0024]    In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims. 
         [0025]    Referring to the drawings,  FIG. 1  shows a corrugation forming die set  10  according to the present invention. 
         [0026]    The upper die  12  includes a die holder member comprised of a flat plate  16  having a mounting spacer block  18  welded or otherwise affixed to the underside thereof. A series of angle brackets  20  are bolted to the upper side of the holder plate  16 . 
         [0027]    The angle brackets  20  are spaced apart to receive the press ram R to which they may be bolted as indicated. This distributes the load imposed on the plate  16  during forming operations. 
         [0028]    Disposed beneath the underside of the plate  16  and attached to opposite sides of the mounting spacer block  18  as by screws are a pair of on edge elongated forming bars  22  parallel to each other and projecting downwardly from the underside of the holder plate  16 . 
         [0029]    The forming bars  22  are radiused at  24  on at least their lower corners facing away from each other. This radius approximately corresponds to the radius desired to be formed at the intersection of the corrugation sides S and bottom B of the sheet metal workpiece W. The forming bars  22 A may also be rounded at  24 A as seen in  FIG. 9  to be reversible. 
         [0030]    A lower die  26  is adapted to be secured on the press bed  28  and includes a U-shaped base  30  having a pair of spaced apart upright parallel legs  32 , each having attached one of a pair of spaced apart parallel forming bar  34  affixed on edge to the inside of a respective leg  32  projecting upwardly. 
         [0031]    Each of the lower die forming bars  34  have a radiused corner  35  facing towards each other approximately corresponding to the desired radius between the intersecting corrugation sides S and tops T. 
         [0032]    The forming bars  22  of the upper die  12  are more closely spaced than the forming bars  34  of the lower die  26  to be able to move between the forming bars  34  during forming of a corrugation in a sheet metal workpiece P. 
         [0033]    The clearance space between the two sets of forming bars  22 ,  34  and the depth of the forming bars determines the inclination of the sidewalls S of the corrugation in the sheet P as indicated. 
         [0034]    The corrugation sides S may be formed with a greater or lesser inclination depending on the location and dimensions of the die components. The inclination is typically of interest to a designer as the less inclination of the sides the stronger the corrugated panels are, but more material is required as the sides S become steeper. Thus, this inclination can be set to a designer&#39;s requirements by varying the relative widths A, B between the forming bars  22 ,  34 . 
         [0035]    The depth of the corrugations is another parameter which can be controlled by varying the heights of the pairs of forming bars  22 ,  34 . 
         [0036]    Hardened wear strips  38  can be installed on the under surface of the die holder plate  16  along each side which can also act as thin spacers for slightly adjusting the depth that the forming bars  22  reach into the lower die  26 . 
         [0037]    A resilient strip  40  (polyurethane, 90 durometer) may be partially recessed into the bottom  42  of U-shaped base  30  to “overbend” the bottom B and make the same flatter by compensating for spring back (see  FIG. 1B ). 
         [0038]      FIG. 3  shows a change in the location of the components and thus the corrugation configuration by increasing the spacing width of the upper die pair of forming bars  22  by adding a U-shaped spacer  44  and narrowing slightly the width of the spacing of the lower die forming bars  34  by adding a thin spacer sheet  46 . 
         [0039]    The sides S of the corrugation will thereby be formed at a steeper angle. 
         [0040]    In  FIG. 4 , a narrower U-shaped spacer  48  is used with the upper die pair of forming bars  22  and thicker spacers  50  are assembled between the legs  32  and the forming bars  34  to create slightly steeper corrugation sides S. 
         [0041]      FIGS. 5 and 6  show how the thin sheet spacers  48  and thick spacers  50  can be switched and/or both stowed on the sides of the legs  32 . 
         [0042]      FIG. 8  shows an alternative shape of the forming bars  34 A in which all four corners  36 A are radiused. This allows switching of the exposed corners to the engaging position to extend the life of the bar  34 A. 
         [0043]      FIG. 9  shows another alternative shape of the forming bars  22 A in which both ends may be rounded to in effect provide four larger radius corners  24 A. 
         [0044]    In use, the upper and lower dies are of a length to form a corrugation the full length of the sheet W. After each corrugation is formed, the sheet W is then shifted between the dies to bring the next unformed section into position in readiness for forming the next corrugation, and so on until the sheet W is formed with the number of corrugations required. 
         [0045]    The forming bars and spacers are configured as necessary to form the desired corrugation. The individual components are simple and able to be made cheaply to allow almost any desired corrugation geometry to be formed and eliminates the necessity of having many convention dies or of using the very slow process of forming the corrugations by successive bending operations while allowing a great number of corrugation configurations to be made.