US 3516572 A
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June 23, 1970 P. DAVIS CLOSURE HAVING DOUBLE FASTENING MEANS Filed Sept. 5, 1968 z Sheets-Sheet l 95% f Il,
ATTORNEYS June 23, 1970 Filed Sept. 5, 1968 P. DAVIS CLOSURE HAVING DOUBLE FASTENING MEANS \\'lllllllllll.ll
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ATTORNEYS United States Patent C 3,516,572 CLOSURE HAVING DOUBLE FASTENING MEANS Paul Davis, Swampscott, Mass., assigner to Sweetheart Plastics, Inc., Wilmington, Mass., a corporation of Maryland Filed Sept. 6, 1968, Ser. No. 758,000 Int. Cl. B65d 43/10 U.S. Cl. 220--60 7 Claims ABSTRACT F THE DISCLOSURE A disposable flexible plastic lid having a closure wall and a downwardly extending skirt with a pair of beads which may be continuous or interrupted and extend inwardly on the skirt, and which serve as primary and secondary retaining means to hold the lid on the rim of a container. The secondary bead also serves to prevent compacting of the lid when stacked with other identical lids.
This invention relates to disposable lids for containers and more particularly comprises a disposable flexible plastic lid having primary and secondary beads in its skirt for retaining the lid on the rim of a container.
`Conventional cover-all lids are ordinarily provided with a single retaining bead on the lid skirt for holding the lid in place on the rim of a container. When the lid is lifted accidentally off the container rim over even a small portion of its periphery, the seal at the container mouth is broken and the contents may spill from the container and the whole lid can be stripped from the container rim lwith almost a negligible force to expose its contents.
One important object of this invention is to provide a secondary retaining bead at the periphery of the lid so as to retain the lid on the container rim even when a part or all of the first bead is lifted off the rim and which will seal the container closed when the entire primary head is lifted over the container rim. It is recognized that when the rim is cross threaded between the beads, a seal may not be formed.
Another important object of this invention is to utilize the retaining bead on the cover-al1 lid skirt for stabilizing a stack of identical lids nested one upon the other.
Another more general object of this invention is to improve the sealing facility incorporated into the skirt of a cover-all lid.
Yet another important object of this invention is to improve the sealing capability of cover-all lids without increasing their cost.
Another important object of this invention is to provide a lid which allows for changes in the volume of the container.
To accomplishgthese and other objects, the disposable flexible plastic lid of this invention includes a closure wall and a downwardly extending peripheral skirt. A container rim engaging wall is formed at the top of the skirt and cooperates with the closure wall to form a seat for the rim of a container to be closed by the lid. An inwardly extending bead is provided in the skirt below the container rim engaging wall to form a snap acting latching device to retain the lid on the container with the container rim at the seat. A secondary bead is provided in the skirt below the rst bead that defines a second rim seat and which serves as a secondary snap acting latching device to retain the lid in place on the container rim even ice when a portion or all of the primary bead is lifted over the rim of the container.
These and other objects of this invention along with its incident advantages will be better understood and appreciated from the following detailed description of two embodiments thereof, selected for purposes of illustration and shown in the accompanying drawing in which:
FIG. 1 is a side view of a container closed by a lid constructed in accordance with this invention;
FIG. 2 is an enlarged fragmentary cross sectional view of the container rim and lid of FIG. l;
FIG. 3 is a View similar to FIG. 2 but taken on a vertical plane displaced circumferentially a few degrees from the plane of FIG. 2;
FIG. 4 is a fragmentary side View, of a plurality of lids identical to the lid shown in FIG. 1 and arranged in nested relationship;
FIG. 5 is a view similar to FIG. 2 but showing the lid in a different position with respect to the container rim;
FIG. 6 is a cross sectional View taken along the section line 6 2 of FIG. 2; and
FIG. 7 is a side view similar to FIG. 4 but showing the stacked relationship of the two lids when one is displaced laterally with respect to the other.
In FIG. l a container 10 is shown having an upwardly flared side wall 12 and a bottom wall 14. The upper edge of the side Wall 12 has a rolled rim 16. The container is, of course, merely representative of all forms of paper and plastic containers and per se forms no part of this invention. The container is shown closed by lid 18 which comprises this invention.
The lid is generally composed of a closure wall 20 and a downwardly extending skirt 22 secured to the periphery of the closure wall 20. The lid is of the cover-all type so as to provide maximum sanitary protection for the cup rim 16 and the cup contents.
The closure wall '20 in the embodiment shown is made up of a top ange 24 having a step 26 intermediate its ends and a top wall 28 and an inner shoulder 30 joined by the vertical wall 32. The closure wall 20 also includes central circular diaphragm 34 and an undercut portion 36 which is generally tapered upwardly and inwardly from the periphery of the diaphragm 34 and further is joined to the inner edge of the ange 20. The undercut portion 36 forms a stacking ring in the closure wall 20 so as to enable the lid to nest with other identical lids in a stable stack in the manner shown in FIG. 4. This general form of nesting facility is required to enable the lids to be mechanically handled in automatic filling and capping equipment as well as to be stored economically and handled manually in other settings.
The skirt 22 is shown in the drawings to have an upper generally Vertical container rim engaging wall 38 and a pair of subtending beads 40 and 42 along with an outturned edge 44 at its lower end. It will be noted in FIGS. 2 and 3 that when the container is closed by the lid under normal circumstances, the rolled rim 16 of the container lies in a seat generally defined by the ange 20, the vertical Wall 38, and the bead 40. Conventionally a seal is formed -between the rolled rim 16 and the vertical Wall 38 and/or the wall 28 so as to protect the container contents.
The beads 40 and 42 are shown in FIGS. 13 to extend about the entire skirt 22, and each has an inner diameter somewhat less than the normal maximum diameter of the container measured at the outer edge of the rolled rim 16. Therefore, when the lid is mounted on the rim of the container in the manner shown in FIG. l, the skirt 22 of the lid and/ or the rim must distort somewhat to allow the bead 40 to pass over the rim to the position shown.
In FIG. the lid 18 is shown displaced from the position of FIG. l on the rim 16. In this position, the bead 42 serves to retain the lid on the rim 16. It will be noted that the lid is partially lifted from the rim 16 so that the rim no longer is located in the primary seat defined by the flange 20, vertical wall 38, and the bead 40. Nevertheless, the lid is still retained firmly in place on the container 1by virtue of the secondary retaining bead 42. And if the bead 16 lies wholely within the groove defined between the two beads 40 and 42 about the entire periphery of the Container, a seal is formed about the rim 16. The seal may in part be defined by the lower portion of the bead 40, the upper portion of the bead 42 and the wall between, depending upon the spacing between the beads. If the beads are close together, the two cooperate to form a lid rim seat. Alternatively, if a substantial gap is provided between the two beads, the space between them may form a secondary vertical wall which functions as the vertical wall 38 to form a seal against the side of the rolled rim.
The bead 42 performs a function other than a secondary rim retainer, as is suggested in FIGS. 4 and 7, It will be noted that the bead 42 reduces the radial distance between the side wall 36 'which includes the undercut portion of the nesting ring and the shoulder 32. That is, the gap between the skirt 22 and the periphery of the diaphragm 34 is lessened by the intrusion of the bead 42, and the effective width of the gap is substantially less than the radial width of the flange 20. Consequently, when an axially directed force is applied to the edges of the nested stack of lids, the bead 42 resists entry of the flange of one lid into the space between the periphery of the diaphragm and the skirt of the next upper lid. As a result, the lids will not compact under pressure to form stickers which would make them unsuitable for mechanically handling.
In FIG. 4 the manner in which the nesting ring cooperates with the nesting ring of other lids to hold the lids in a vertical stack is shown. It will be noted in that figure that the periphery 46 of the diaphragm 34 serves as a lower external shoulder which seats on the upper internal shoulder 30 of the next lower lid in a stack to hold the lids in the relationship shown. The undercut portion 36 of the closure wall makes the minimum diameter of the inner shoulder 30 substantially less than the maximum diameter of the outer shoulder 46, and consequently a wide platform is presented to support the lids in nested relationship. In the absence of the undercut portion 36, the interference between the shoulders would be limited to the stock thickness, and because of the flexibility of the material, this interference would not be sufllcient to hold the lids in the desired relationship.
In FIG. 7 the upper lid is shown displaced to the right, with the lower shoulder 46 of the upper lid inside the upper shoulder 30 of the lower lid so as to be unsupported by it. However, the lower end 44 of the skid 22 of the top lid rests on the flange 28 of the lower lid to support the two lids in stacked relationship. Because the laterial distance between the skirt and shoulder is less than the radial width of the top wall 24, the skirt will support the upper lid on the top of the lower lid when the lids displace laterally. This function is important particularly when the lids are slice fed during mechanical handling.
In the embodiment illustrated, additional axial stiffness is added to the skirt by the spaced axially extending ribs 50. The ribs 50 span beads 40 and 42 but do not extend into the rim engaging vertical wall 38 so that they do not interfere with the formation of a seal when the lid is seated in the position shown in FIGS. l-3.
Preferably the peaks 51 of the ribs do not reach the plane of the outer surface of the skirt so as not to interfere with the formation of a secondary seal when the container rim is held by the lower bead 42. The rib however spans each of the beads to give some axial stiffness to the ribs. It is to be understood that the vertical ribs are not necessary for proper functioning of the primary and secondary beads and it is within the scope of this invention that they may be omitted. The ribs however prevent the skirt from collapsing axially under pressure, and therefore, make it somewhat easier to push the lid off the rim. In their absence, the push may just cause the skirt to curl under the rim and not unseat from it. Further, the ribs may assist in stripping the lid from the mold during manufacture by somewhat increasing the radial flexibility of the skirt. If the undercuts of the beads 40 and 42 is great, this may be important.
The double seat on the lid provides yet another advantage. It is apparent upon inspection of FIGS. 3 and 5 that when the lid secured as shown in FIG. 3, the capacity of the container 10 is less than if attached as in FIG. 5. Thus the lid provides a variable capacity for the container with which it is used, which may compensate for different volume requirements established by different states to house a particular quantity of product.
From the foregoing description, those skilled in the art will appreciate that modifications may be made of this invention without departing from its spirit. For example, the lid of this invention need not include the step 26 in the top flange. Therefore it is not intended that the breadth of this invention be limited to the two embodiments described. Rather, it is intended that the scope of this invention be determined by the appended claims and their equivalents.
What is claimed is:
1. A flexible disposable plastic lid comprising a closure wall and a downwardly extending peripheral skirt,
a container rim engaging wall formed on the skirt to engage the periphery of a container rim when the container is closed by the lid,
an inwardly extending bead in the skirt below the rim engaging wall for engaging the container rim to retain the lid on the container with the rim contacting the engaging wall,
and a second inwardly extending bead in the skirt below the first bead for engaging the container rim when the first recited bead is pulled over the rim, to serve as a secondary restraint to hold the lid on the container.
2. A flexible disposable lid as described in claim 1 further characterized by said beads being interrupted by axially extending ribs provided in skirt to give the skirt axial stiffness, said ribs terminating at the top beneath the rim engaging wall.
3. A flexible disposable lid as described in claim 1 further characterized by said closure wall including a generally radially extending flange connected at its periphery to the skirt,
a side wall extending down from the inner edge of the flange, a circular diaphragm connected to the inner edge of the side wall,
and a stacking ring formed in the side wall for supporting the lid in nested relation with an identical lid.
4. A flexible disposable lid as described in claim 3 further characterized by said beads being interrupted by axially extending ribs provided in skirt t'o give the skirt axial stiffness, said ribs terminating at the top beneath the rim engaging wall. y
5. A flexible disposable lid as described in claim 3 further characterized by said stacking ring having an undercut portion extending upwardly and inwardly from the periphery of the circular diaphragm, the lower end of the undercut portion being spaced from the second bead a distance less than the radial width of the ange. 6. A flexible disposable lid as described in claim 5 further characterized by said beads being interrupted by outwardly and axially extending ribs that span the beads at spaced points about the skirt to stiffen the skirt axiall the outer radial extent of the ribs being radially within the rim engaging wall. 7. A exible disposable lid as described in claim 6 further characterized by 6 the'lower end of the skirt terminating in a plane perpendicular to the lid axis adjacent the plane of the diaphragm.
References Cited UNITED STATES PATENTS 3,065,875 11/1962 Negoro 220--60 3,321,104 5/ 1967 Edwards 220--97 3,321,124 5/1967 Bank .229-43 10 GEORGE T. HALL, Primary Examiner U.S. C1. X.R.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent; No. 3, S16 572 Dated June 23 1970 Inventods) Paul Davis It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 2 line 2l "6-2" should read 6-6 same line and" should read lines 22-24 should be canceled;
Column 3, line 26 "FIGS 4 and 7" should read FIG 4 line 40 "mechanically" should read mechanical lines 58 69, should be canceled.
Signed and sealed this 17th day of August 1971 (SEAL) Attest:
EDWARD M.FLETCHBR,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents USCOMM-DC 60376-969 FORM PO-IOSO (1U-69) n u s Govskrmrrm rnlmmoornr: nu n-ww aa
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