Patent Publication Number: US-7591054-B2

Title: Insertion die tooling for flange installation and the method of use

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates in general to metal drum fabrication and the insertion die tooling associated with this fabrication. The present invention more specifically relates to the configuring of the drum end with an installed, internally-threaded flange and the associated insertion die tooling. The referenced flange is constructed and arranged for receipt of an externally-threaded closing plug. The present invention relates to the construction and arrangement of the insertion die tooling and modifications to that tooling that relate directly to the installation of the flange into an embossment formed in the metal of the drum end. 
     Prior to loading the drum end onto a corresponding work station of the insertion die tooling, the metal drum end is formed with the embossment which provides a shaped annular pocket that is constructed and arranged to receive the flange. Thereafter, in terms of the fabrication sequence, the metal of the drum end is formed over, under, and around the flange so as to securely anchor the flange into the drum end. This basic construction method and configuration is well known in the industry and represents technology that has been practiced for several years. Traditionally, the initial forming of the drum end pocket or embossment included an outer annular wall that had a generally cylindrical shape and an upper, substantially planar panel that was substantially perpendicular to the outer annular wall. In this final configuration, the drum end material does not extend into the open interior defined by the flange outer wall. 
     This flange and drum end construction and structural relationship is described generally in U.S. Pat. No. 5,943,757, in the context of a new one-step insertion die. The &#39;757 patent issued Aug. 31, 1999 to Magley and is incorporated by reference herein in its entirety. One difference between the &#39;757 patent and prior art fabrication methods and tooling is the forming of the embossment as one step in the overall sequence as contrasted to having that embossment pre-formed in the drum end prior to loading the drum end onto the lower work station. Importantly, in the context of the present invention, neither the &#39;757 patent nor the prior art installation constructions for metal flanges disclose any inner axial wall being formed as part of the drum end. The reference to “inner” refers to an axial wall being formed on the inside of the flange. While the basics of the crimping procedure so as to install a flange into the drum end pocket or embossment are believed to be well known, this fabrication is performed without the use of any inner axial wall for these types of metal flanges. 
     In U.S. Pat. No. 4,588,103, a plastic closure (20), shaped as an internally-threaded flange, is installed into boss (41) that is formed in the metal drum end (42) as illustrated in FIG. 2 of the &#39;103 patent. The insertion tooling illustrated in FIG. 5 of the &#39;103 patent includes a center holding and forming die (53) which is of annular shape and contoured along its lower surface so as to fit snugly up against upper wall (45) after forming inner wall (44) of boss (41). Inner wall (44) and outer wall (43) are substantially concentric with one another. Center annular portion (55) helps to form inner wall (44) and is positioned against inner wall (44) as the crimping members or collets (54) act on boss (41). Importantly, the center annular portion (55) is cylindrical. 
     In U.S. patent application Ser. No. 10/971,874, filed Oct. 22, 2004 and published Dec. 8, 2005 as Publication Number US-2005-0269330-A1, an inner annular wall is formed in a metal drum end as a part of the overall insertion construction for a metal, internally-threaded flange. The forming of the drum end includes shaping an outer annular wall that is generally cylindrical, an upper, generally planar panel, and the inner wall. As illustrated in FIG. 10 of the &#39;874 application, the inner wall (27) is inwardly and downwardly tapered into a frustoconical form. The insertion of the metal flange into the drum end and its final installation involves the application of opposing inner and outer forces directed against portions of the drum end material. 
     The present disclosure is directed to an improvement in the insertion die tooling by changing the cylindrical form of the center annular portion or pilot into a frustoconical form. As one example of a pilot, refer to portion (55) in the &#39;103 patent. This same modification, according to the present disclosure, would be applicable to any prior art insertion die tooling where a cylindrical center form or pilot is used for the shaping of a generally cylindrical inner wall. This particular change in the insertion die tooling results in an improved structure as compared to an inner tooling form that is cylindrical. One benefit derived from the present disclosure is the ability to change the thickness of the drum end material without having to change the insertion die tooling for proper installation of the flange. 
     BRIEF SUMMARY 
     Insertion die tooling for the installation of a flange into a drum end embossment according to one embodiment of the present invention comprises a work station constructed and arranged to receive an internally-threaded metal flange and a portion of a metal drum end, the metal drum end being formed with an embossment to be positioned over the metal flange and a movable pressure unit including a closing collet, a punch holder attached to a closing ring, and a pilot that is constructed and arranged to be movable with movement of the punch holder, the pilot including a frustoconical portion constructed and arranged for engagement with the embossment for forming an inner drum end wall adjacent an inner surface of the flange. 
     One object of the present disclosure is to describe improved insertion die tooling for the installation of a flange into a drum end embossment. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a front elevational view, in full section, of insertion die tooling in an open position according to a typical embodiment of the present invention. 
         FIG. 2  is a front elevational view, in full section, of the  FIG. 1  insertion die tooling in a closed position with a flange and drum end inserted. 
         FIG. 3  is a front elevational view, in full section, of a drum end embossment formed prior to placing the drum end in the insertion die tooling. 
         FIG. 4  is a front elevational view, in full section, showing the final installation of the flange into the embossment as shaped by the  FIG. 1  insertion die tooling. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations and further modifications in the illustrated device and its use, and such further applications of the principles of the disclosure as illustrated therein being contemplated as would normally occur to one skilled in the art to which the disclosure relates. 
     Referring to  FIGS. 1 and 2 , there is illustrated insertion die tooling  20  according to the present disclosure. The present disclosure describes a preferred embodiment of the invention. Tooling  20  includes a stationary, lower work station  21  and an axially movable upper pressure unit  22 . The lower work station  21  is constructed and arranged for receipt of the flange  24  and a portion of the drum end  23 . The preferred embodiment is illustrated for a three-quarter inch (¾″) flange  24  which represents the typical type of flange for the venting location of the drum. It is expected that a second work station will be included for installation of a two inch (2″) flange that is used for a dispensing closure. As illustrated and described in U.S. Pat. No. 5,943,757, providing two work stations, one for the two inch flange and one for the three-quarter inch flange, enables use of the same type of pressure unit, a portion of which is shown as unit  22 , and the same (simultaneous) sequence of installation steps. For the purposes of this disclosure, the insertion die tooling  20  for a two inch flange  24  is selected and illustrated. The same basic structure and steps would apply for the three-quarter inch flange, simply scaled dimensionally for proper sizing. It is also to be understood that combining the two work stations provides added efficiency since the entire drum end  23 , in one step, is able to be loaded onto both work stations, concurrently, and both flanges installed with substantially the same process steps and sequence. 
       FIG. 1  illustrates insertion die tooling  20  in what is described as an “open” position prior to the loading of the flange  24  and prior to placement of the drum end  23  over the flange within the tooling  20 .  FIG. 2  illustrates insertion die tooling  20  in what is described as a “closed” position after all of the forming and installing steps have been performed. In progressing from the  FIG. 1  position to the  FIG. 2  position, the selected flange  24  is placed into receiving pocket  27  that is defined by fixture  28 . Fixture  28  in turn is assembled into position on base  29  that forms part of the lower work station  21 . When the drum end  23  is formed for receipt of flange  24  by a one-step insertion die, as that disclosed in U.S. Pat. No. 5,943,757, the drum end  23  arrives at work station  21  with a substantially flat or planar interior portion that will be formed to receive the two inch and three-quarter inch flanges. When the drum end is not formed by a one-step insertion die, the drum end  23  is pre-formed with a flange-receiving embossment  30 , as illustrated in  FIG. 3 . 
     The flange  24 , as positioned in pocket  27 , is centered on axial centerline  31  that extends through the axial (geometric) center of pocket  27  and through the axial center of the pilot  32  that is assembled into the pressure unit  22  and is surrounded by closing collet  33 . The closing collet  33  actually consists of a series of individual collet sections or segments, referred to herein as closing collets  33 . The flange  24  includes an upper surface  34  and an inner (un-threaded) annular wall  35  (see  FIG. 4 ). The inside diameter of wall  35  is larger than the inside diameter of the opening  36  of the embossment  30 . Opening  36  is substantially circular with an axial centerline  37  that is substantially coincident with centerline  31 . In this way, the radial lip  38  of embossment  30  extends inwardly toward centerline  37  beyond the inner, annular surface  35   a  of annular wall  35 . In the prior art designs for the metal flange and drum end combination, the radial lip  38  of the embossment  30  did not extend (in the final assembly) beyond the inside surface of the annular wall of the metal flange. This is shown in U.S. Pat. No. 5,943,757 in FIG. 5A. 
     Assuming that the outside diameter of the two inch metal flange remains substantially the same and assuming that the flange inside diameter, at its upper surface, stays substantially the same, then by reducing the size of the opening  36  of embossment  30 , there is sufficient material to form over into an inner annular wall that extends downwardly into the interior of the flange away from the flange upper surface. This inner drum end wall is illustrated in U.S. patent application Ser. No. 10/971,874. An inner drum end wall, for a plastic closure flange, is disclosed in U.S. Pat. No. 4,588,103. 
     In U.S. Pat. No. 4,588,103, the center annular portion (55) that moves axially into the opening defined by the inner wall (44) of the drum end (42) is cylindrical. In a similar manner, the inserting portion or pilot for the angled inner wall of U.S. patent application Ser. No. 10/971,874 can be cylindrical. The diameter of this axially-moving pilot in turn helps to determine if there is any angle of incline of the inner drum end wall and if there is, the details of its frustoconical shape, including the final dimensions. Since the angled or inclined inner wall influences gasket compression and release, the angle of incline and the inside diameter sizes of the inner wall along its axial length are important. 
     The insertion die tooling  20  provides a novel and unobvious change to the prior cylindrical form of the pilot that was used for a plastic closure flange. Insertion die tooling  20  includes a pilot  32  that is constructed and arranged with a frustoconical surface  41  that is adjacent to and pushes against the radial lip  38  of drum end material in the process of creating the frustoconical inner drum end wall  42 . The pilot is surrounded by a series of six closing collets  33  that pivot inwardly to push the drum end material beneath the flange lip  43  and against the outer edge  44  of the flange lip  43 . While the closing collets  33  are pivoting inwardly, the pilot  32  is moving in a downward axial direction so as to push downwardly and outwardly on the frustoconical inner drum end wall  42 . These opposing inner and outer forces tightly secure the metal of the drum end  23  in, over, under, and around the flange  24 , specifically the flange lip  43  and wall  35 . As was noted in U.S. patent application Ser. No. 10/971,874, these opposing forces that act against each other also provide a type of back-up support for each other, enabling much higher compression forces to be applied, as compared to the prior art structures for a metal flange that do not include an inner annular wall. As such, any serrations that might be included about the outer surface of the flange lip are not required for a tight and securely installed flange  24  into the drum end  23  embossment  30 . 
     With continued reference to  FIGS. 1 and 2 , the pressure unit  22  further includes a punch holder  47  that is assembled to a closing ring  48  by three, equally-spaced socket head cap screws  49 . A socket head cap screw  50  extends through the punch holder  47  and threads into the upper portion  51  of pilot  32 , generally concentric with axial centerline  52 . Cylindrical pockets  53  are machined into the punch holder  47  and receive springs  54  that assist in the movement of the closing collets  33 . The closing collets  33  float within the hollow interior of the closing ring  48  and are captured by their shape and by the shapes of the surrounding parts, including the closing ring  48 , punch holder  47 , and pilot  32 . As would be understood from U.S. Pat. No. 5,943,757, downward movement of pressure unit  22  initially places the lower surface  58  of each collet  33  directly against the upper surface  59  of the drum end  23  just immediately to the outside of the outer edge  44  of flange lip  43 . Based upon the  FIG. 1  illustration, the pilot  32  has not yet moved fully into the flange. 
     The next step in the process is for the punch holder  47  and closing ring  48  combination (i.e., assembled together with cap screws) to move axially toward the drum end  23  and flange  24 . As this movement occurs, the angled face  60  of the closing ring pushes inwardly on the contacted face  61  of each collet. This causes each collet  33  to pivot its lower edge inwardly, drawing drum end material inwardly below the flange lip  43 . The axial movement of punch holder  47  means the same axial movement for pilot  32 . The pilot  32  first contacts the inner edge of the radial lip  38  of the drum end that defines upper opening  36 . With continued axial travel of pilot  32 , the inner wall  42  is formed as the pilot pushes downwardly and outwardly against inner wall  42 . This outwardly directed force is applied concurrently with the inwardly directed force from the collets  33 . As described, these opposing forces and the back-up reinforcement or support provided by the pilot  32  enables significantly higher compressive forces to be applied to the drum end material that extends around the inside and outside of flange  24 . 
     The corresponding tooling  20  is novel and unobvious in terms of its structure and use. Creating a frustoconical form  41  for that portion of the pilot  32  that forms the inner wall  42  is an improvement. Further, the ability to use that frustoconical form as a back-up reinforcement and as a way to generate an outwardly directed force is an improvement. 
     A further benefit has been identified as a result of the frustoconical form for that portion of the pilot  32 , as contrasted to a pilot construction that employs a cylindrical form. When the flange design and its installation into a drum end embossment would permit a thinner drum end material to be used, that would result in a cost savings. One reason that a thinner material would be acceptable is due to the higher compressive forces that can be used. The question then is whether the insertion die tooling can remain the same as the material thickness changes and becomes thinner or changes back to a thicker form. A critical factor in this analysis is the addition of the inner drum end wall  42 . 
     When an inner annular drum end wall is included as part of the flange installation construction, an inside diameter opening is created, shown as D 1  in  FIG. 4 . When a generally cylindrical pilot is used, typical of the known prior art, its outside diameter is fixed and is the same throughout is axial extent or length. This outside diameter helps to define the magnitude of the outwardly directed forces and the degree of interference with the inner wall  42 . When the drum end material is made thinner, then in order to form and compress the inner wall  42  in the desired manner, the cylindrical size of the pilot needs to be increased to match the D 2  dimension (see  FIG. 4 ). Varying or changing the axial depth of insertion of the cylindrical pilot into the flange does not affect the condition created by the size difference. If the pilot size is not changed for the thinner drum end material, then the inner wall  42  will not be fully formed in the desired manner. By changing the insertion die tooling  20  to include a frustoconical portion  41  as part of the pilot  32 , changes in the drum end material thickness can be accommodated without the need to change or redesign the tooling. Since the diameter size of portion  41  increases as the frustoconical taper diverges in a direction away from the flange, all that would need to be done is to insert the pilot farther into the flange so as to achieve the intended design form to inner wall  42  and to exert the desired outwardly directed force. 
     In terms of the axial travel of pilot  32  and accordingly of frustoconical surface  41 , an interesting effect occurs. With a thinner drum end material, the upper surface of the radial lip  38  material that extends over flange lip  43  is lower, i.e., closer to the flange lip  43 . This in turn means that before the lower surface of the collets  33  contact the upper surface of the radial lip, the pressure unit must axially travel a little farther, this added distance corresponding to the reduction in thickness. This then means that that the starting position of the pilot  32  and surface  41  is a little farther in the direction of the flange. The axial travel of the punch holder  47  and closing ring  48  combination can remain substantially the same, but the pilot actually goes deeper into the flange for an increased amount of travel that generally corresponds to the change in the material thickness of the drum end. While there is not a 1:1 correlation due to the frustoconical angle of taper, it is very close considering the magnitude of the dimensional changes to the drum end material thickness. 
     While the preferred embodiment of the invention has been illustrated and described in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that all changes and modifications that come within the spirit of the invention are desired to be protected.