Abstract:
The invention described herein is a shaped seal or gasket for use with a screw cap as commonly used in chemical barrels. The shaped gasket has a profile that includes a winged portion for contacting a sealing surface. The winged portion of the gasket defines a concave surface. The gasket has a second surface, or zone of contact, for contacting against a second surface, such as the underside of a screw cap. The winged portion of the gasket profile is wider than the zone of contact. The gasket profile can take on many different configurations, as shown in the drawings.

Description:
RELATED APPLICATIONS 
   This application is a continuation-in-part of U.S. patent application Ser. No. 10/902,631 filed Jul. 28, 2004 now abandoned which claims priority to U. S.Provisional Application No. 60/490,607 filed on Jul. 28, 2003. 

   FIELD OF THE INVENTION 
   The invention relates a shaped gasket generally used in association with a cap to seal vessels, drums, casks, barrels or containers for containing liquid, or other applications where and air or liquid tight seal are required. An example of such a container is a 55 gallon drum having an aperture in its lid, the aperture being adapted to receive the cap and gasket, the gasket forming an air or watertight seal. 
   SUMMARY OF THE INVENTION 
   The disclosure herein is for a gasket or seal generally used with a screwcap. A typical application is the screw plug found in 55 gallon drums used for containing liquids. However, one skilled in the art will recognize that the gasket profiles described and claimed herein have applications in other apparatus where an air or watertight seal is desired, and need not be limited to annular gaskets . 
   The threaded cap and gasket shown herein is generally used for 55 gallon storage drums, and is screwed into a threaded hole or aperture in the drum. The threaded aperture is often times formed by inserting a flanged receiver into the lid or side wall of the drum. The flanged portion remains outside of the drum, with a cylindrical portion bearing the threads extending into the interior of the drum. The flanged portion then forms a bearing or sealing surface for the gasket when the cap is screwed in to the threaded aperture. 
   One skilled in the art will recognize that other types of securing structure could be used to secure the cap instead of threads. For example, the cap could be secured by friction fit, bayonet mount, or other mechanisms known for securing a cap or plug into an aperture. In any instance, the shaped gasket is included to form a water or air tight seal between the cap and a bearing surface surrounding the aperture. 
   The gaskets shape includes a portion that contacts the cap, and distended wing portions that form a profile wider than the portion of contact with the cap. The portion of the gasket between the distended portions is generally concave, so as to form two areas of initial contact with the opposing sealing surface. In some embodiments, the sealing surface may be shaped to provide a convex surface opposing the concave surface of the gasket. The gasket may be made of any material commonly used for gaskets, such as rubber, nylon, silicone, urethane, neoprene, polypropylene, polyethylene, or any other pliable material used in the gasket industry. The gasket may be made of the same material as the cap, and be formed as a unitary structure with the cap. Additionally, the gasket may be attached to the cap by a co-molding process, where the gasket and cap may or may not e constructed of the same material. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross sectional view of a threaded cap and shaped gasket. 
       FIG. 2  is a cross-sectional view of the preferred embodiment of the gasket profile. 
       FIG. 3  is a cross-sectional view of an alternate embodiment of the gasket profile. 
       FIG. 4  is a cross-sectional view of an alternate embodiment of the gasket profile. 
       FIG. 5  is a cross-sectional view of an alternate embodiment of the gasket profile. 
       FIG. 6  is a cross-sectional view of an alternate embodiment of the gasket profile. 
       FIG. 7  is a cross-sectional view of an alternate embodiment of the gasket profile. 
       FIG. 8  is a cross-sectional view of an alternate embodiment of the gasket profile. 
       FIG. 9  is a cross-sectional view of an alternate embodiment of the gasket profile. 
       FIG. 10  is a cross-sectional view of a further alternate embodiment of the gasket profile. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   With reference to  FIGS. 1 and 1A , a threaded cap  10  and gasket or seal  20  are shown in association with a threaded receiver  30  inserted into an aperture, such as would be used in the lid  35  of a 55 gallon drum or other container. The cap  10  includes a top portion  9  and a cylindrical portion  8  having threads. The receiver  30  includes a cylindrical portion  31  and a flange  33 , the cylindrical portion  31  of the receiver adapted to receive the cylindrical portion  8  of the cap  10 , allowing the cap  10  to be screwed into the receiver. In general, the underside  11  of the cap  10  is parallel to the flange  33 , but such a relationship is not necessary. The flange  33  extends about the perimeter of the aperture a sufficient distance so as to form a sealing or bearing surface  34  for the gasket or seal  20 , positioned on the underside  11  of the cap  10 . In an alternate embodiment, the gasket or seal  20  bears upon the lid  35  of the drum. One skilled in the art will recognize the bearing surface  34  can be any structure below the underside  11  of the cap, such that the surface will form a water or airtight seal when the cap  10  is tightened into the receiver  30 . 
   The gasket or seal  20 , shown in profile in the drawings, is annular and extends around the cap  10 . Although the gasket can touch both the cylindrical portion  8  and the top  9  of the cap  10 , the gasket  20  can also be sized or positioned so that it does not contact the cylindrical portion  8  of the cap  10 . In the preferred embodiment, the gasket or seal  20  has a zone of contact or attachment  21  that contacts the underside  11  of the cap  10 . The zone of contact  21  may be attached to the cap  10  by a suitable adhesive, bonding, or other means of attachment such as co-molding, or it may be un-adhered and simply be in contact with the cap  10  at the zone of contact  21 . In an alternate embodiment, the gasket  20  and cap  10  are made as a unitary structure, the zone of contact  21  in such an embodiment being defined as the same area of the structure as if the gasket were adhered to the underside  11  of the cap  10 . 
   In the preferred embodiment, the zone of contact or attachment  21  of the gasket  20  is generally flat, as shown in the figures, or corresponds to the shape or surface to which it is contacting. For instance, if the underside  11  of the cap  10  had grooves, it is contemplated that the gasket  20  will have corresponding grooves on the zone of contact or attachment  21 . Such correspondence however, is not necessary. 
   As shown in  FIGS. 1 ,  2 ,  3 ,  7 ,  8 , and  9 , the seal  20  has distending winged portions  22  and  23  that extend away from the zone of contact or attachment  21 . Thus, it is preferred that the widest portion of the gasket, in this instance the distending winged portions  22  and  23 , is wider than the zone of contact  21 . The seal  20  forms a generally concave shape between the ends  40  and  41  of the winged portions  22  and  23 . Within these general parameters, it is recognized that the seal  20  may take different shapes in cross-section or profile, as exemplified in  FIGS. 2 through 9 . Further, it is not required that each of the winged portions be of the same shape. 
   In operation, as the cap  10  is screwed into the receiver  30 , the winged portions  22  and  23  of the seal  20  contact a surface to achieve closure or a water or air tight seal. In the preferred embodiment, the seal is positioned around the cap  10  so that the winged portions  22  and  23  contact the receiver flange  33 , barrel lid  35 , or other bearing or sealing surface  34 . 
   In alternate embodiments, as shown in  FIGS. 4 ,  5  and  6 , the winged portions  22  and  23  extend no wider than the zone of contact or attachment  21 . As the cap  10  is screwed into the receiver  30 , the seal or gasket  20  is compressed between the underside  11  of the cap  10  and the bearing surface  34 . When compressed, the winged portions  22  and  23  of the seal or gasket  20  can extend beyond the width of the zone of contact or attachment  21 . 
   As shown in the figures, the gasket or seal can take on a number of different shapes. One will recognize that the attribute and structures shown in any of the embodiments can be combined with those of the other embodiments to form profiles not shown, but consistent with the claimed invention. For instance, the profile shown in  FIG. 1  could include the concave walls  48  and  49  as shown in  FIG. 6 . 
   As shown in  FIG. 2 , the seal  20  includes distending winged portions  22  and  23  that form an angle of approximately 45 degrees with respect to the underside  11  of the cap  10 . The ends  40  and  41  of the winged portions  22  and  23  are generally rounded. Between the ends  40  and  41 , the concave portion  25  is generally rounded as well, although the surface of the seal between the ends need not assume any particular shape, so long as it is concave. 
   As shown in  FIG. 3 , the seal  20  can include a concave portion  25  that has generally straight walls  44  and  45  that converge at an vertex  26 . Also shown in  FIG. 3 , the distending winged portions can exhibit an angle greater than 45 degrees with respect to the underside  11  of the cap  10 . Such an angular arrangement allows for a larger zone of contact or Attachment  21  and increases the seal  20 &#39;s resistance to compressive forces, as the cap  10  is screwed into the receiver  30 . 
   In the alternate embodiment shown in  FIG. 4 , the winged portions form an angle of 90 degrees with the underside  11  of cap  10 . In such an arrangement, the walls  44  and  45  are essentially perpendicular to both the underside  11  of the cap  10 , and the bearing or sealing surface  34 , when the gasket or seal  20  is in an uncompressed state. The alternate embodiment also demonstrates the ends  40  and  41  of the winged portions  22  and  23  can be generally pointed, rather than rounded. The concave portion  25  is formed by straight surfaces  46  and  47  meeting at an vertex  26 . The distance from the vertex  26  to the underside  11  of the cap  10  is approximately one half of the distance from the ends  40  and  41  of the winged portions  22  and  23  to the underside  11  of the cap  10 . Put another way, the concave portion  25  has a maximum depth that is roughly one half of the total height of the seal  20 . The depth of the concave portion can vary from one eighth of the total height of the seal  20  to seven eighths of the maximum height of the seal  20 . In the case of a co-molded cap and gasket, the maximum depth is not applicable, as the division between the cap and gasket is non-existent. In such an embodiment, the maximum depth of the cap can occur at a level above the underside of the cap. 
   As shown in  FIG. 5 , an alternate embodiment includes winged portions  22  and  23  that do not extend beyond the width of the zone of attachment or contact  21  when the seal  20  is in an uncompressed state. When such a seal  20  is compressed between the underside  11  of the cap  10  and the bearing or sealing surface  34 , the ends  40  and  41  of the winged portions  22  and  23  can extend beyond the width of the zone of attachment  21 . 
   As shown in  FIG. 6 , the walls  48  and  49  extending from the zone of contact  21  to the ends  40  and  41  of the winged portions  22  and  23  can be concave. 
   As shown in  FIGS. 7 ,  8 , and  9 , the seal  20  can be attached to the barrel or flange  33  instead of the cap  10 . In such an arrangement, the underside  11  of the cap  10  becomes the bearing or sealing surface  34 , and the flange  33  bears upon the zone of contact  21 . As shown in  FIGS. 8 and 9 , the sealing surface  34  may include a shape  50  protruding therefrom. Put another way, the bearing or sealing surface  34  need not be flat, but may be convex. The sealing surface  34  can also include contours or any shape or profile, including rounded and angular portions. The shape is received by the concave portion  25  of the seal  20 , thereby providing a greater surface area of contact for the seal  20 . The shape  50  need not be of complimentary shape to the concave portion  25 . As shown in  FIG. 8 , the shape  50  can be generally rounded, and the concave portion  25  of the seal  20  can be angular, having straight surfaces  46  and  47 . However, in other embodiments, the shape  50  can be complimentary, as shown in  FIG. 9 . Such a complimentary arrangement maximizes the contact surface area with the concave portion  25  of the seal  20 . 
   A further alternative embodiment is shown in  FIG. 10 . Similar to the earlier embodiments of the invention, the gasket or seal  120 , while shown in profile, is annual and extends around the cap. The gasket or seal  20  has a zone of contact or attachment  121  that contacts the underside of the cap in the same fashion as described above. The zone of contact  121  may be where the gasket or seal  120  is attached by any suitable means, such as adhesives, bonding, welding, or any other means of attachment such as co-molding, as appropriate. In an alternative, the gasket or seal  120  can be part of the cap and made as a unitary structure. 
   In this form of the invention, the seal  120  has distending winged portions or ribs  122  and  123  that extend away from the zone of contact or attachment  121 . Unlike the earlier forms of the invention, the embodiment shown in  FIG. 10  is not symmetrical, in that the winged portion  123  forms an angle  124  with the cap, the angle  124  being different than the angle  125  that the winged portion  122  forms with the cap. Preferably the angle  124  is on the order of 90° while the angle  125  is on the order of 75°. Also as illustrated, the winged portion  123  extends farther away from the cap than the winged portion  122 . Thus, the main seal is the winged portion  123 , with the winged portion  122  forming a secondary seal. Preferably the wings  122  and  123  are formed about a 15° included angle. 
   As thus illustrated, the gasket or seal  120  is not symmetrical and provides what is believed to be a superior seal. Also, while the preferred configuration is as illustrated in  FIG. 10 , the configuration can be a mirror image of that illustrated, thus with the angle  125  being approximately 90° and the angle  124  being approximately 75°, and the same type of seal will result. 
   While the angles  124  and  125  are preferred within the ranges set forth above, there can be variances from those angles and still be within the scope of the invention, so long as there is a difference of about 15° between the angles  124  and  125 . 
   The description and drawings of the preferred embodiment are merely illustrated in nature, and the present application includes all other embodiments and equivalents that are within the spirit and scope of the described embodiment.