Abstract:
A plastic lid for closing a container neck opening according to one embodiment of the present invention comprises a lid body surrounded by an annular rim, the annular rim defining a gasket channel having an open portion at one end opening toward the container neck opening and including a closed base at an opposite end. The annular rim defines a pair of raised annular beads positioned adjacent the open portion of the channel for capturing a gasket received within the gasket channel. The corresponding gasket may be either a preformed gasket that is inserted into the channel or a foamed-in-place gasket that is formed in the gasket channel. No pretreatment of the lid is required for the installed gasket to be retained in the gasket channel.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates in general to the design of a container lid such as a drum or paid lid and the manner of placing and retaining a sealing gasket in a lid channel. More specifically, the present invention relates to a structural configuration as part of the drum (or other container) lid that facilitates the retention of the sealing gasket without requiring any adhesive for retaining the gasket and without requiring any pretreatment process for the channel of the lid that receives the gasket. The present invention is applicable to both plastic lids and steel (or other metal) lids. However, since the issues that the present invention addresses are more significant for plastic lids, that will be the principal focus of this description. The application of the present invention to a steel or other metal lid is addressed later in the specification.  
         [0002]     When adding a sealing gasket to a drum lid, the two most widely used prior art approaches are to (1) use a flexible, preformed gasket and glue it into a receiving area of the lid, such as a peripheral, annular channel adjacent the outer edge of the lid, and (2) foam the gasket in place by injecting a liquid foam into the channel or receiving area. With the first approach, the adhesive that should be used to glue the gasket in place does not typically adhere to the plastic material of the lid without some type of heat treat pretreatment, such as subjecting the plastic to a flame or to a “corona” gun spark. With the foamed-in-place approach, the same problem exists. In order for the foamed gasket material and resultant foamed gasket to adhere to the lid channel or the intended gasket-receiving area, the described heat treat pretreatment or a similar pretreatment is necessary. The present invention is applicable to any container lid, such as an industrial drum. For the description of the preferred embodiment, a drum lid is used.  
         [0003]     The problem that occurs as a result of this heat treat pretreatment is that the gasket sticks so well to the lid that the gasket cannot be removed cleanly for subsequent reconditioning or recycling. This problem occurs whether the gasket that is installed in the lid is a preformed gasket or a gasket that is foamed in place. One consequence of this problem is that only the center section of these drum lids can be recycled. If one would try to recycle the entire lid, noting the gasket portions or residue and/or the adhesive residue that cannot be removed cleanly, there will be contamination with regard to the remainder of the plastic lid material. If the drum lid is to be reconditioned as contrasted to recycling of the drum lid material, it is difficult to cleanly remove the entire gasket and/or adhesive without damaging the plastic lid in such a way as to effectively destroy or eliminate the reconditioning option.  
         [0004]     As an improvement to the aforementioned practices of installing a sealing gasket into a container lid, the present invention configures the lid with a unique retention bead that keeps the gasket in position without the need to perform any type of pretreatment to the lid in order to hold the gasket in position. The present invention works equally well with either a flexible, preformed gasket or with a foamed-in-place gasket. The redesign to the lid is independent of the gasket style, material, or fabrication method.  
         [0005]     In the case of a steel (or other metal) lid, the preferred method of securely retaining the sealing gasket is to apply adhesive in the case of a pre-formed gasket. As a result, the same removal problems exist for any reconditioning or recycling. If the gasket is foamed-in-place, there can be retention questions if the lid is not pretreated in some fashion to help the foam material adhere. By use of the retention bead(s) of the present invention, the retention concerns or questions are addressed without any extra steps or processes.  
       SUMMARY OF THE INVENTION  
       [0006]     A lid for closing a container neck opening according to one embodiment of the present invention comprises a lid body surrounded by an annular rim, the annular rim defining a gasket channel having an open portion at one end opening toward the container neck opening and including a closed base at an opposite end. The annular rim defines gasket-retention means positioned adjacent the open portion for capturing a gasket received within the gasket channel. The corresponding gasket may be either a preformed gasket that is inserted into the channel or a foamed-in-place gasket that is formed in the gasket channel.  
         [0007]     One object of the present invention is to provide an improved container lid and gasket combination without lid pretreatment or gasket adhesive being required.  
         [0008]     Related objects and advantages of the present invention will be apparent from the following description.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a partial, side elevational view of a plastic lid and gasket combination according to one embodiment of the present invention.  
         [0010]      FIG. 1A  is a partial, enlarged view, in full section, of an alternative retention bead geometry according to the present invention.  
         [0011]      FIG. 2  is a partial, side elevational view showing one alternative embodiment to the  FIG. 1  combination, according to the present invention.  
         [0012]      FIG. 3  is a partial, side elevational view showing another alternative embodiment to the  FIG. 1  combination, according to the present invention.  
         [0013]      FIG. 4  is a partial, side elevational view of a metal lid and gasket combination according to another embodiment of the present invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]     For the purposes of promoting an understanding of the principles of the invention, 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 invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.  
         [0015]     Referring to  FIG. 1 , there is illustrated in partial form a plastic drum lid  20  arranged in combination with a sealing gasket  21  that is fabricated of an elastomeric material. The annular lid  20  has an orientation in  FIG. 1  as it would be applied in the downward direction onto an open, annular end of a drum or similar container. For example, a container of the type contemplated as part of the subject invention would have a neck portion and a neck opening (not illustrated) constructed and arranged to receive drum lid  20  wherein sealing gasket  21  establishes a sealed interface between channel  22  and the upper edge of the drum or container neck opening. The upper edge of the container neck opening is constructed and arranged to push upwardly into channel  22  of lid  20 .  
         [0016]     Channel  22  of lid  20  is defined by outer peripheral rim  23 . Annular rim  23  includes an annular outer wall  24 , an annular inner wall  25 , and an annular upper wall  26  that defines a closed base for channel  22 . In terms of an axial direction, the area of channel  22  that is opposite and actually below upper wall  26  is the channel opening that is facing or directed toward the upper edge of the container neck opening (not illustrated). The three walls  24 ,  25 , and  26  define the overall position and shape of channel  22 . Sealing gasket  21  is positioned and retained in channel  22  without the need for any bonding adhesive and without the need for any pretreatment of the plastic material that creates the surfaces of channel  22 . While there are two embodiments for the style of gasket  21  (preformed and foamed-in-place), the structure of lid  20 , including channel  22 , does not change with these different gasket styles.  
         [0017]     The focus of the present invention is directed to the fact that gasket  21  can be used and retained without requiring any pretreatment. Related to this aspect of the present invention is the addition of a retention bead on an inner surface of channel  22 . In the  FIG. 1  illustration, one raised annular bead  30 , appearing as a radially outwardly projecting, rounded rib, is unitarily molded as part of inner wall  25 . A second raised annular bead  31 , appearing as a radially inwardly projecting, rounded rib, is unitarily molded as part of outer wall  24 . In terms of vertical or axial positioning, bead  30  is generally aligned with bead  31 , as if generally coplanar. In  FIG. 1A , an alternative annular bead  31   a  shape is disclosed that is more square than rounded. It is to be understood that either bead shape is suitable for the present invention so long as it is constructed and arranged to properly function to retain the gasket  21  in channel  22 .  
         [0018]     While beads  30  and  31  have been described as “annular”, it is to be understood that one embodiment of the present invention configures either or both beads  30  and  31  in a partial or segmented form. For example, in lieu of a complete 360 degrees extent for beads  30  and  31 , one embodiment of the present invention envisions creating each bead into four sections, equally spaced, with a clearance space or gap between adjacent bead sections. For example, one contemplated possibility is to provide four bead sections for each bead with a 60 degree circumferential extent separated from one another by a space or gap of 30 degrees. Another option for four bead sections would be to include each section with a 45 degree circumferential extent with a spacing or separation between adjacent beads of 45 degrees. These same alternatives apply to the alternative shape represented by bead  31   a.    
         [0019]     As would be understood, the radial width of opening  32  of channel  22  is closed slightly by or due to the raised heights of beads  30  and  31 , whether as annular beads or as segmented beads with the individual segments spaced apart from one another. When gasket  21  is constructed and arranged as a preformed gasket, it is not adhesively bonded (glued in) to the inner surface(s) of channel  22 . As such, there is nothing to hold or retain gasket  21  in position in channel  22 . This is where the beads  30  and  31  come into use. The reduction in the radial width of channel  22  by the addition of beads  30  and  31  prevents gasket  21  from falling out of channel  22 . However, gasket  21  can be readily and easily extracted from channel  22  by manually pulling on the gasket, such as with a pair of pliers. This is due to the width of channel  22  and the elastomeric material used for gasket  21 . Importantly, gasket  21  can be cleanly removed without leaving behind any gasket portions or pieces or any gasket residue and without leaving behind any adhesive residue. This in turn permits the lid  20  to be reconditioned without damaging the lid to the point that it is effectively destroyed in terms of reconditioning. Alternatively, the absence of any pretreatment and the use of beads  30  and  31  permit lid  20  to be recycled without the risk that any gasket pieces or portions or any gasket residue or any adhesive residue will be left behind and will contaminate the recycled plastic material of lid  20 .  
         [0020]     When gasket  21  is constructed and arranged as a foamed-in-place gasket, there is no pretreatment required for the surfaces of channel  22  in order for this style of gasket to be captured and retained in channel  22 . The typical pretreatment for plastics of this type and for this application is a heat treating technique such as the use of a flame or a corona gun spark. However, nothing in terms of a surface treatment or any other pretreatment is required with respect to channel  22  in order for that channel to accept and retain a foamed-in-place style for gasket  21 . The beads  30  and  31 , whether annular in form or segmented form, provide a sufficient “closing” of channel opening  32  in order to prevent any fall out of gasket  21  from within channel  22 .  
         [0021]     The preferred design for the present invention is depicted by the  FIG. 1  structure, including a pair of beads  30  and  31 . However, in terms of closing a portion of opening  32 , so as to reduce the opening width a sufficient degree to capture gasket  21 , the combined radial “height” of these two beads can be introduced into a single bead that would either be annular in form or segmented. In  FIG. 2 , this style of single bead  36  is illustrated as part of lid  37 . Bead  36  has a raised height (in a radial width direction) that is substantially equal to the combined raised height of beads  30  and  31  in  FIG. 1 . Further, single bead  36  is positioned as part of inner wall  25   a.  Alternatively, a single bead  38  that is unitarily formed as part of lid  39 , can be positioned as part of outer wall  24   a,  see  FIG. 3 .  
         [0022]     Since gasket  21  can be readily and easily installed or formed into channel  22  and then removed without leaving behind any gasket portions or pieces or gasket residue, and without leaving behind any adhesive residue, the entire lid can be recycled without contamination or reconditioned without damage.  
         [0023]     In terms of the method steps to fabricate the combination of lid  20  and gasket  21 , the lid  20  is injection molded into the form illustrated, in partial form, in  FIG. 1 , including beads  30  and  31 . The next step is to either install a preformed gasket into channel  22  or create a foamed-in-place gasket into channel  22 , using a foamable gasket -material. Regardless of the style of gasket created/installed, that step is performed without any prior pretreatment to the lid. When recycling the lid and gasket combination, the gasket is pulled out of the channel and the lid is recycled. No prior clean up step is needed to remove any gasket material, any gasket residue, or any adhesive residue.  
         [0024]     With reference to  FIG. 4 , a metal (steel) lid  50  is illustrated in partial form with an elastomeric sealing gasket  51  installed into gasket channel  52 . The gasket channel  52  includes a radially inwardly extending bead  53  and a radially outwardly extending bead  54 . Beads  53  and  54  are constructed and arranged relative to channel  52  and gasket  51  in a manner virtually identical to how beads  30  and  31  cooperate with channel  22  and sealing gasket  21 . Except for the fact that lid  50  is fabricated out of steel, rather than plastic (i.e., lid  20 ), the  FIG. 4  structural combination is virtually identical to the  FIG. 1  structural combination. By the use of beads  53  and  54 , adhesive is not required in order to retain gasket  51  in channel  52 . It is also envisioned that a larger single bead could replace the pair of beads  53  and  54 . It is further contemplated that the shape of beads  53  and  54  can be more rounded in form and less square.  
         [0025]     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.