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.
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.
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.
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.
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.
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.
One object of the present invention is to provide an improved container lid and gasket combination without lid pretreatment or gasket adhesive being required.
Related objects and advantages of the present invention will be apparent from the following description.
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.
Referring to
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.
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
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 31a.
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.
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.
The preferred design for the present invention is depicted by the
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.
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
With reference to
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.