Abstract:
A container assembly for transporting and storing flowable materials according to one embodiment of the present invention comprises a drum including a lip edge defining a top opening, a lid constructed and arranged to fit over and close the top opening, a closing ring constructed and arranged for securing the lid to the lip edge, and an elastomeric gasket positioned between the lip edge and the lid, the lip edge being constructed and arranged for the formed sidewall, shaped to define a hollow interior, said sidewall including an outwardly facing, concave section.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates in general to a container and lid combination that includes a sealing gasket and uses a closing ring assembly. The closing ring is of the open-hoop style that can be used for open head drum-styled containers. Containers of the type disclosed herein may range from the smaller pail sizes of approximately 1 gallon up to much larger industrial drum sizes. The container material may be either plastic or metal. The closing ring is used to securely attach a matching closing lid to the open end of the container. The sealing gasket is positioned between the closing lid and the open end of the container. Containers of the type disclosed herein are formed as generally cylindrical structures with an upper, generally circular open end. The circular open end is defined by an upper peripheral lip of the container. The container is closed by tightly securing a matching closing lid over the open end of the container. The sealing gasket is annular in form and positioned between the lid edge and container lip edge in an effort to try and create a sealed interface. These component parts are axially clamped together as the closing ring us reduced in circumference. It is important to tightly connect the lid to the container in order to close and seal in the container contents and prevent any loss or leakage of those contents. The closing ring and gasket are used in cooperation with the lid and container structures for this purpose. 
         [0002]    Since the entire contents of the container may not always be dispensed when the drum (container) is first opened after initial filling, it is important to be able to re-close the container with the matching lid with substantially the same degree of security and tightness that was achieved at the time of initial filling and closing. Presently, the two most commonly-used closing ring structures employ either a tightening bolt arrangement or an over-center lever and linkage arrangement. The bolt arrangement requires manual tightening and untightening of the bolt into or out of a nut or at least an internally-threaded block. The torque applied to the bolt and the relative sizing of the ring body relative to the diameter of the lid dictates the degree of tightness and thus the degree of gasket compression and the security of the lid-to-container connection. 
         [0003]    The over-center lever and linkage arrangement uses a linkage with multiple pivots and a lever handle that is folded to close the container and unfolded or pivoted outwardly. This opening action allows the ring circumference to expand and this removes or relieves the clamping forces on the lid and drum lip. This in turn allows the container to be “opened” by removing the lid. The lever handle in cooperation with the pivot points and linkage members makes use of the mechanical advantage and leverage of the structure to enable a tight closing operation, while still being performed manually. By enabling the manual folding of the lever handle to apply a sufficient clamping force by means of the closing ring to properly compress the gasket and secure the lid to the container, the time required to unthread or thread the clamping bolt of the other (first referenced) configuration is eliminated. The tighter the clamping force applied by the closing ring, the greater the level of manual force that must be applied to the lever handle. However, the relative force levels depend in part on the configuration of the linkage and it would be an improvement to what presently exists to be able to achieve the same ring clamping (closing) force with less lever force. The relative force levels also depend in part on the construction and arrangement of the sealing gasket and the shaped of the lid edge and of the container lip edge. 
         [0004]    The configuration of the linkage is the subject of pending U.S. patent application Ser. No. 11/542,529, filed Oct. 3, 2006, entitled CONTAINER AND LID COMBINATION WITH CLOSING RING ASSEMBLY, and this application is incorporated by reference herein, in its entirety. 
         [0005]    The construction and arrangement of the sealing gasket, including its specific outer peripheral shape and interior construction, is one of the subjects of the present disclosure. The construction and arrangement of the container lip edge, including its shape and construction, is also one of the subjects of the present disclosure. Importantly, the interface and cooperation between the sealing gasket and the container lip edge is a part of the present disclosure. While the lid and the lid edge construction and arrangement are important, they are not the primary focus of the present disclosure. However, due to interior pressurization and inversion of the lid, there are force dynamics that play a part in the construction and arrangement of the gasket and edge lip interface, and these force dynamics are important. In a similar manner, the design and construction of the closing ring is not the primary focus of the present disclosure. Nevertheless, it is important to the overall assembly and it is the tightening action of that closing ring that secures the lid onto the drum and compresses the sealing gasket in the desired manner. 
         [0006]    According to the present disclosure, there is a new sealing gasket design, a new plastic container (drum) lip edge design, and a new metal container (drum) lip edge design. The current gasket design is included since its use and performance are improved by applying it to either of the new container lip edge designs. Similarly, the new gasket can be used with the current container lip edge designs and still provide improved use and performance. The improvements provided by the structures disclosed herein are considered to be novel and unobvious. 
       BRIEF SUMMARY 
       [0007]    A container assembly for transporting and storing flowable materials according to one embodiment of the present invention comprises a drum including a lip edge defining a top opening, a lid constructed and arranged to fit over and close the top opening, a closing ring constructed and arranged for securing the lid to the lip edge, and an elastomeric gasket positioned between the lip edge and the lid, the lip edge being constructed and arranged with a formed sidewall, shaped to define a hollow interior, the formed sidewall including an outwardly facing, concave section. 
         [0008]    One object of the present disclosure is to provide an improved container assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0009]      FIG. 1  is an exploded, perspective view of a prior art container that is suitable for being modified with the improvements provided by the present disclosure. 
           [0010]      FIG. 2  is a partial, side elevational view, in full section, of the  FIG. 1  container. 
           [0011]      FIG. 3  is a partial, side elevational view, of a prior art plastic container similar in certain respects to the prior art container of  FIG. 1 . 
           [0012]      FIG. 3A  is a partial, side elevational view, in full section, of an alternative prior art plastic container. 
           [0013]      FIG. 4  is a partial, side elevational view, in full section, of a prior art elastomeric gasket. 
           [0014]      FIG. 5  is a partial, side elevational view of the  FIG. 4  prior art gasket as installed in a prior art container according to  FIG. 1 . 
           [0015]      FIG. 6  is a partial, side elevational view, in full section, of another prior art elastomeric gasket. 
           [0016]      FIG. 7  is a partial, side elevational view of the  FIG. 6  prior art gasket as installed in a prior art container according to  FIG. 1 . 
           [0017]      FIG. 8  is a partial, side elevational view, in full section, of yet another prior art elastomeric gasket. 
           [0018]      FIG. 9  is a partial, side elevational view of the  FIG. 8  prior art gasket as installed in a prior art container according to  FIG. 1 . 
           [0019]      FIG. 10  is a partial, front elevational view of a container according to a typical embodiment of the present invention. 
           [0020]      FIG. 11  is a partial, front elevational view of the  FIG. 10  container as assembled with a lid, gasket, and closing ring. 
           [0021]      FIG. 12  is a partial, front elevational view, in full section, of the  FIG. 11  construction after the closing ring has been tightened into position so as to compress the gasket. 
           [0022]      FIG. 13  is a partial, front elevational view, in full section, in diagrammatic form, showing the compression of the gasket and the higher density and lower density compression zones. 
           [0023]      FIG. 14  is a diagrammatic representation of the  FIG. 13  container assembly without the benefit of the  FIG. 10  container design showing the nature of gasket compression at the time of internal pressurization. 
           [0024]      FIG. 15  is a side elevational view, in full section, of an annular sealing gasket for use in combination with both the  FIG. 10  container design and the  FIG. 14  container design according to a typical embodiment of the present invention. 
           [0025]      FIG. 16  is a partial, side elevational view, of the  FIG. 15  gasket as used with the  FIG. 14  container. 
           [0026]      FIG. 17  is a partial, side elevational view, in full section, of the  FIG. 15  gasket as used with the  FIG. 10  container. 
           [0027]      FIG. 18  is a partial, side elevational view of the  FIG. 17  assembly after the closing ring has been tightened into position so as to compress the gasket. 
           [0028]      FIG. 19  is a diagrammatic illustration of gasket compression based on the  FIG. 18  construction after container pressurization. 
           [0029]      FIG. 20  is a partial, side elevational view, in full section, of a plastic container lip edge according to the present invention. 
           [0030]      FIG. 21  is a partial, side elevational view, in full section, of the  FIG. 20  plastic container as used with the  FIG. 15  gasket prior to container pressurization. 
           [0031]      FIG. 22  corresponds to the  FIG. 21  illustration and diagrammatically discloses the container pressurization and movement of the lid. 
           [0032]      FIG. 23  is a partial, side elevational view, in full section, of the  FIG. 20  container in combination with a prior art gasket and further including the  FIG. 21  lid and  FIG. 21  closing ring. 
           [0033]      FIG. 24  is a diagrammatic illustration based on  FIG. 23  with the container pressurized. 
           [0034]      FIG. 25  is a side elevational view, in full section, of an annular sealing gasket according to another embodiment of the present invention. 
           [0035]      FIG. 26  is a partial, front elevational view, in full section, of a container assembly using the  FIG. 25  gasket. 
           [0036]      FIG. 27  is a partial, front elevational view, in full section, of another container assembly using the  FIG. 25  gasket. 
       
    
    
     DETAILED DESCRIPTION 
       [0037]    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. 
         [0038]    Referring to  FIGS. 1 and 2 , there is illustrated a steel drum and lid assembly  20  according to the prior art. Assembly  20  includes a generally cylindrical drum  21 , an annular sealing gasket  22 , a closing lid  23 , and a closing ring  24 . This prior art assembly  20  (see  FIG. 2 ) includes an annular drum lip edge  25  that has a generally circular form in lateral cross section with a hollow interior. As illustrated, the gasket  22  is positioned on the curved upper surface  26  of edge  25  below the curved edge  27  of lid  23 . The closing ring  24  includes spaced-apart upper and lower flanges  28  and  29 , respectively. Upper flange  28  fits over lid edge  27  and lower flange  29  fits below lip edge  25 . 
         [0039]    Referring now to  FIG. 3 , a prior art plastic drum and lid assembly  32  is illustrated. Assembly  32  includes a generally cylindrical plastic drum  33 , an annular sealing gasket  34 , a closing lid  35 , and a closing ring  36 . The construction of assembly  32  is substantially the same as that of assembly  20  in terms of the arrangement of the component parts. The plastic construction does result in various changes to the shapes and material thicknesses of the drum, the lid, and the gasket. A comparison between  FIGS. 2 and 3  makes clear both the similarities and the overall arrangement of the component parts of assemblies  20  and  32  as well as the differences in the shapes and material thicknesses due to the differences between metal (assembly  20 ) and plastic (assembly  32 ). 
         [0040]      FIG. 3A  illustrates an alternative prior art lip edge  37  design for a plastic container suitable for use as part of assembly  32  as a replacement for the  FIG. 3  plastic drum  33 . 
         [0041]    Referring to  FIGS. 4-9 , three different prior art annular sealing gaskets  39 ,  40  and  41  (see  FIGS. 4 ,  6  and  8 ) are illustrated. In the companion assembly drawings of FIGS.  5 ,  7 , and  9 , the positioning and appearance of the corresponding gaskets is illustrated at the start of the assembly process, prior to any significant or noticeable gasket compression. The only differences between assemblies  42 ,  43 , and  44  is the gasket selection. The metal drum  45 , closing lid  46 , and closing ring  47  are the same in each assembly  42 ,  43 , and  44 . Gasket  39  has a generally rectangular shape in lateral cross section. Gasket  40  has a generally circular shape in lateral cross section. Gasket  41  has a semicircular sleeve shape in lateral cross section. 
         [0042]    With this description and explanation of the prior art assemblies, drums (containers) and gaskets as a starting point, the new designs for and for use with metal containers are illustrated in  FIGS. 10-13  and  15 - 18 . The new designs for and for use with plastic containers are illustrated in  FIGS. 20-24 . 
         [0043]    Referring first to  FIG. 10 , a new steel drum  50  construction is illustrated according to the present disclosure. In  FIGS. 11 and 12  the current (i.e., prior art) gasket  51  style is used in combination with new drum  50  as part of assembly  52 .  FIG. 11  illustrates the start of the assembly process for assembly  52 , prior to full gasket compression.  FIG. 12  illustrates the completed assembly  52 . The closing lid  46  and closing ring  47  are the same as used with the prior art assemblies of  FIGS. 5 ,  7 , and  9 . 
         [0044]    With continued reference to  FIG. 10 , the drum  50  includes a generally cylindrical body  50   a  with a formed lip edge  54  that defines opening  50   b . The annular lip edge  54  of drum  50  has a formed sidewall with a hollow, tubular shape with a concave section  55 . The sidewall material is coiled in a counterclockwise direction back into body  50   a . Section  55  is located on what would be understood as the upper and outer portion or quadrant of the tubular form of lip edge  54  based on this lateral cross sectional view. If a circle in a mathematical sense this would be a second quadrant location. The depth of the concavity of section  55  is significant in comparison to a full circle or cylinder. The inward curvature, i.e., the concavity, faces upwardly and outwardly. Concave section  55  is bounded by transition edges  56  and  57  where the concave form changes to a convex form or shape, representing the remainder of lip edge  54 . This lip edge, but for the concave section  55 , would be viewed as being substantially circular in lateral cross section or cylindrical if linear. It is also to be understood that the lip edge  54  defines the open end of the drum and that in the majority of designs that opening will be generally circular. Importantly, the concave section  55  in combination and cooperation with lid  46  creates a capturing pocket  58  that captures a portion of gasket  51  as the closing ring  47  is secured in position (see  FIG. 12 ). In terms of circular geometry, section  55  has a circumferential extent or arc length of between 60 and 90 degrees. 
         [0045]    Referring to  FIG. 11 , it will be seen that the starting positioning of gasket  51  within assembly  52  is generally centered on transition edge  56 . Importantly, the capturing pocket  58  creates a gasket-receiving area or volume that is significantly larger than the height of clearance gap  62  located between transition edge  56  and the inner surface  63  of lid  46 , see  FIG. 12 . 
         [0046]    Containers of the type generally described herein, once filled with the selected contents, typically experience an internal pressure build up (i.e., pressurization). This pressurization causes the lid  46  or edge panel of the final assembly to invert in shape in terms of actually bowing out as illustrated, for example, in  FIG. 13 . The inner panel  64  of lid  46  is actually re-shaped into the  FIG. 13  form due to pressurization and this movement of the lid  46 , in terms of inverting and re-shaping itself, causes the outer edge  65  of lid  46  to actually be pulled on and rolled inwardly. This action with regard to edge  65  in turn pulls inwardly on the gasket material that is captured in pocket  58  and actually attempts to pull that larger mass of elastomeric material through a significantly smaller clearance gap  62 . The concave curvature of section  55  also creates something of an abutment to retard or restrict such motion and this abutment is facilitated by the limited movement of gasket material through gap  62 . As a result of this abutment and the limited passage of elastomeric material through gap  62 , there is actually created a high density compression zone  66  on one side of transition edge  56  with section  55  comprising the inner or lower side of compression zone  66 . On the other (inward) side of transition edge  56 , the gasket material is not compressed as much and is actually part of a lower density compression zone  67 . This reference to “density” means the degree of compression experienced by the portions of gasket  51  that are either radially outwardly of transition edge  56  (high density compression) or radially inwardly of transition edge  56  (low density compression) and the pressure of the gasket against the confining surfaces. The new container annular lip edge shape represented in part by concave section  55  helps to hold the gasket in position and facilitates maintaining the necessary seal when the container end panel (i.e., lid  46 ) reverses direction (inverts) due to interior pressurization. 
         [0047]    When the closing ring is being closed or tightened, typically by a linkage and lever arrangement, its circumference is reduced and in turn the diameter is reduced. This tightening movement of closing ring  47  has the effect of drawing or pushing the closed end of the concave form inwardly toward the lid  46 , gasket  51 , and the container or drum lip edge  25 . The degree of axial separation between flanges  28  and  29  becomes smaller in the direction of the closed end  70 . The reduction in the axial separation or spacing between flanges  28  and  29  draws the lid  46  down onto the gasket  51  and compresses the elastomeric gasket material against the drum lip edge  55 . The presence of concave section  55  creates an enlarged, annular pocket or cavity for movement of a portion of the gasket as it is compressed. The gasket requires less compression before being fully seated. 
         [0048]    In  FIG. 14 , a prior art drum  73  is illustrated in partial form with a lid  46  inverted due to pressurization. The gasket  51  is pushed more, as compared to  FIG. 13 , into the drum interior and it loses surface pressure. The result is leakage. Without the shaped drum lip edge, specifically concave section  55 , there is nothing to help capture and hold the gasket and retain it in the desired position. As more of the gasket material is able to displace toward the interior of the drum, there is nothing significant in terms of gasket compression and there is no high density compression zone. As the lid inverts and the edge of the lid pulls and rolls inwardly, the outer portion of the gasket is pulled inwardly, but without any significant abutment surface or narrow gap to help hold or capture the gasket. This in turn causes the loss of surface pressure and the resulting leakage. 
         [0049]    Referring now to  FIGS. 15-19 , a new annular gasket  77  is illustrated and is disclosed as it is used on a prior art drum lip edge  78  and on the newly styled drum lip edge  25  that includes concave section  55  and transition edges  56  and  57 . The new gasket  77  is described in  FIG. 15  as being a lateral cross sectional view. Since the gasket  77  is preferably annular in form, the illustrated section is created by a radial cutting plane through the gasket body along one side portion. Gasket  77  is an extruded rubber member and this process permits a wide range of shapes. 
         [0050]    With continued reference to  FIG. 15 , unitary, elastomeric gasket  77  includes a hollow body  79  comprised of a side wall  80  defining the hollow interior  81 . The sidewall  80  includes, in lateral section, a generally semicircular, convex upper portion  80   a  and a lower portion  80   b  including curvilinear section  80   c  and concave section  80   d . The shape of the hollow interior  81  follows the general shaping of portions  80   a  and  80   b , meaning that the wall thickness of gasket  77  is substantially uniform. The only exceptions to this uniform thickness are “corners”  82  and  83  that are thicker than the remainder of the sidewall  80 . As noted, gasket  77  can be used with the prior art drum lip edge  78  (see  FIG. 16 ) as well with a new style of drum lip edge  25 , as disclosed herein, see  FIGS. 17 and 18 . 
         [0051]    The precise initial positioning of gasket  77  on top of transition edge  56  and around lip edge  25  is illustrated in  FIG. 17 . The gasket edge  84  between section  80   c  and section  80   d  provides an additional abutment up against transition edge  56  for capturing gasket  77  in position, creating a high density compression zone  66 , as has been described. 
         [0052]    In terms of this disclosure and its use of “compression”, part of what happens is the deforming of the gasket material into a conforming shape that matches the surrounding space that receives the gasket. Rubber gaskets are generally not “compressible” as one would think of for foam material gaskets. Otherwise, the integrity of the sealed interface is influenced by how tightly the gasket is clamped between the capturing surfaces. For a foam material, compression can occur as the air pockets are closed. This action increases the density of the compressed portion. 
         [0053]    In  FIG. 18 , a gasket  77  is compressed to an intermediate stage or degree prior to pressurization of the container and lid inversion (see  FIG. 13 ). When the lid  46  inverts, the lid  46  outer edge pulls and rolls inwardly and creates, relative to gasket  77 , what is illustrated in  FIG. 13  for gasket  55 . In  FIGS. 16 and 19 , gasket  77  is used in cooperation with drum lip edge  78 . As compression begins with the tightening of the closing ring  47 , the concave section  80   d  seats itself in a conforming manner onto the upper curvature of edge  78 . As closing ring tightening and gasket compression continue, the radially outer portion of gasket  77  shifts to the outer surface of edge  78  and uses gasket edge  84  as a way to help seat and capture gasket  77  in that position. As the lid  46  inverts, the gasket  77  stays in position, a result facilitated by the outer peripheral shaping of gasket  77 . The result is illustrated in  FIG. 19  wherein there is a higher density compression zone  88  and a lower density compression zone  89 . 
         [0054]    Using an elastomeric material for gasket  77  that has a higher durometer than the material for gasket  51  permits more controlled gasket shaping and contouring to be maintained. Creating hollow interior  81  provides added flexibility and compressibility to offset the higher durometer (i.e., harder) elastomeric material used for gasket  77 . Otherwise, the compression of gasket  77 , the action of lid  46  under pressurization, and the creation of the higher density and lower density compression zones are all substantially the same as described for gasket  51  and illustrated in  FIGS. 11-13 . This substantially similar result applies whether gasket  77  is used with drum lip edge  25  or is used with drum lip edge  78 . The higher density and lower density compression zones are thus created and enhanced sealing is achieved. Suitable materials for gasket  51  include both foam and a soft grade of rubber, likely less than a 40 Shore A hardness. A foam material would preferably be a urethane foam sponge. For gasket  77 , the shaping to requires an extruding process and a rubber material with a 40-60 Shore A hardness is preferred. 
         [0055]    The gasket and drum combinations that are suitable for what has been described include the new gasket  77  with either a prior art drum lip edge  78  or with the newly styled drum lip edge  25  and the prior art gasket  51  with the newly styled drum lip edge  25 . Each of these combinations pertain to metal drums. There are though improvement options for plastic drums and plastic pails in terms of reshaping the drum lip edge and reshaping the gasket. These combinations are illustrated in  FIGS. 20-24 . 
         [0056]    Referring first to  FIG. 20 , the new plastic drum  92  sidewall  93  is illustrated in lateral section with the newly shaped annular drum lip edge  94 . Drum lip edge  94  includes a substantially straight inner axial wall  95  which, in its full annular form, would be considered cylindrical. Outwardly, curved recess  96  extends into lower shelf  97 . Shelf  97  extends into first wall section  100 . Second wall section  101  is radially inset and axially spaced from section  100  by ramp section  102 . The slight incline to section  101  causes the combination of section  101  and section  102  to create a concave appearance in lateral cross section. Top edge  103  is substantially planar and separated from wall section  101  by curved section  104 . Section  104  has a generally concave shape. 
         [0057]    Referring now to  FIG. 21 , container assembly  105  is illustrated as a partial view, in full section, including the new plastic drum  92  and lip edge  94  in combination with new gasket (hollow)  77 , current lid  107 , and the current closing ring  108 .  FIG. 21  represents the starting condition and position of the individual parts of assembly  105 . In  FIG. 22 , the condition and position of the individual parts of assembly  105  are illustrated when pressurized. The lid  107  has shifted its position due to pressurization and the inverted movement causes outer edge  109  to pull and roll inwardly. This action pulls on gasket  77  and captures it in a compressed condition against the outer surface of lip edge  94 . Virtually the entire mass of gasket  77  is captured against the outer surface of lip edge  94 , thereby creating the previously referenced and described higher density compression zone. While there is a lower density compression zone, located on the inner side of top edge  103 , the amount of gasket material that is pulled into that zone is quite limited and constitutes a very small percentage of the overall mass of gasket  77 . 
         [0058]    Referring now to  FIGS. 23 and 24 , the assembly  112  includes the conventional (prior art) gasket  51 . In  FIG. 23 , the starting position of the component parts that comprise assembly  112  are illustrated. In  FIG. 24 , that same assembly  112  is illustrated with the drum interior pressurized and the outer lip of lid  107  being pulled and rolled inwardly.  FIGS. 23 and 24  correspond to  FIGS. 21 and 22 , respectively, except for the change in gaskets. Current gasket  51  is used in assembly  112 , while new gasket  77  is used in assembly  105 . 
         [0059]    As should be understood from the present disclosure, if the gasket shape (in lateral cross section) begins in its free form closer to its final (net) shape as compressed between the lid and drum, then there would be less movement of the gasket required. This concept of less movement occurs axially in terms of lid movement, radially in terms of gasket compression and movement, and circumferentially in terms of ring closing. 
         [0060]    Another example of a gasket that is suitable for this disclosed application and assembly is illustrated in  FIG. 25 . Gasket  120  has a “peanut” shape in lateral cross section and can be fabricated from a urethane foam sponge, but preferably from an extruded rubber in the 40-60 Shore A hardness range. The reduced size center portion  121  is constructed and arranged to fit over and to be centered generally on transition edge  56  of assembly  122  (see  FIG. 26 ). When used with a prior art drum, this center portion  121  is centered over the uppermost portion of the circular shape, as illustrated for assembly  123  (see  FIG. 27 ). 
         [0061]    Enlarged end  124  seats within capturing pocket  58  and is subjected to the pulling forces as described above, as the lid inverts due to pressurization. Opposite end  125  is not subjected to these same compression forces. Accordingly, enlarged end  124  creates the high density compression zone  126  of assembly  122  which enlarged end  125  creates the low density compression zone  127  of this assembly. 
         [0062]    The initial shaping of gasket  120  includes a narrow center portion  121  and this portion fits closely in gap  128 . Due to this initial shaping, very little movement is required for the gasket to achieve its final form in this particular location. The enlarged end  124  is sized and shaped to conform generally to the size and shape of capturing pocket  58 . While gasket compression is still required for a tight and secure seal, the amount of movement to achieve proper gasket compression is less when the gasket is pre-shaped in the manner described. 
         [0063]    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.