CA1124685A - Linerless closure - Google Patents

Abstract

LINERLESS CLOSURE

ABSTRACT OF THE DISCLOSURE

A closure cap made of a molded plastic material which provides an effective seal with a container finish, particularly when the contents are a highly evaporizable liquid, and is capable of being mass produced economically. The cap is characterized by sealing means in the form of a series of con-centric flanges and ribs depending from the inside surface of the top of the cap engageable with the container finish at radially spaced circumferential extending zones. The series comprises inner and outer radially spaced flanges of a given vertical height and two intermediate ribs of a shorter vertical height between the flanges which are spaced relative to the container finish so that when the cap is seated; the outer flange engages the outer rim of the container finish, the ribs engage a radial wall thereof and the inner flange in one form of finish engages an inwardly tapered wall section and in another form, engages the radial wall adjacent the inner rim.

Description

BACKGROUND OF THE INVENTION

The present inventi~n relates to improvements in con- !
~i tainer closures and more specifically to a one~piece plastic i closure having integral sealing means engageable with the co~-! tainer finish to seal the container contents~ These closure j~ caps are commonly referred ~o as ~linerless closures~.
l~l Linerless closures are not new per se and generally ill consis~ of a top and a depending skirt having internal screw !1~ threads which engage with complementary threads on the neck of , a container for applying and removing the cap and sealing mean~
I depending from the top and engageable with the container in~.sh.
~ The sealing means ;n these prior linerless closures generaL~
¦¦ consists of one or more seali~g rings or flanges which depend from the inside surface of the top and eDgage the finish or end ~ surface defining the disch~arge opening in th~ neck of a con-; 1¦ tainer such as a bottle.ii Typical oi closure assembl~es of ~hi3 ~ype are those ¦ shown in the following U. S. patents: J.A. Mclntosh, No. 3~286, ~:~
Il 866, R. H. Gibson~ ~. 3,2.32,470, J. W..Wandellg No. 3,053,40~
!¦ and W. J. Marks, No. 3,815,771. In each of these paten~s there il is shown a one-piece closure of generally c~p-like shape having I, a series of sealing rings depending from the inside ~ur~ace o~

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the top of the cap adapted to engage the flnish or axial e~ld face of the container when the cap is applied thereto. The containers are usually made of glass by a conventional process.
It has been observed that surface irregularities in the form of depressions or undulations in the finish of ~he glass are ~uite common, particularly in the surface of the a~ial end face of the container as illustrated in McIntosh, No. 3,286,866 Other common imperfections include small projections or pips and small pock-like openings. It can readily be appreciated ~a~ ¦
îf the sealing rings confront a depression or enga8e a pro- ¦
jection directly~ there is the likelihood of a leakage path which may produce actual leakage of product if large enough and the container is not in an upright position as is sometlmes the case during shipment and storage. In the case of an easily vapori~ed product, there is loss even when the containe~ is resting on its base Accordingly, it can be seen that es~e~ ¦
tia`lly single zone sealing as in McIntosh or the doubl~ zo~ ¦
seal of the other r~ferences may not be effective to block the potentia`l leakage paths crea~ed by imperfections o tha type noted above. Furthermore, it has been observed that a.relative !
ly rigid wall section of the cap characteristic of some of the caps in Marks, No. 3~815,771~ does not conform to surface imp~r--;
fections a readily as a flexible resilient flange or rib.
Ihus~ the present inven~ion is designed to provide a sealing _3_ .

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arrangement consisting of a pl-urality of resilien~ f~ex1ble '; elements which engage the con~a~ner at a plurality of zones , including the inner and outer rlm of ~he container and at points ,1 between the rims which combined define a series of baxriers ! blocking leakage ~-~ectively.

Accordingly, the present invention provides an ! in~proved linerless closure capable of effectively sealing I~ highly evaporizable products by providing a seal which Il minimizes product loss and which nevertheless is easily removed even after the sealed container has been stored , a substantial period of time.
,1 Also the present invention provides an improved linerless closure which may be economically produced by ---- r l1 a conventional molding process.
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ii SUMMARY OF THE INVENTION ¦
il Th2 above and o~her objects of the invention are ¦1, achieved by provision of a closure having a top and a depending j '` sk~rt and means on the interior of the skirt for secur-Lng the closure in place on a container. The locking means may comprise¦
1 complementary screw threads on the interior of the skirt anc~ the~ r~
i' neck of a container such as a conventional bottle, In the I i ,, `~

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present instance the closure cap includes sealing means in the ~ orm o~ a series of radially spaced, circumferentially extend-jj ing flexible flanges and ribs depending from the inside top o~
the closure which are of varying axial height and which when I the closure is in a seated or locked position provide a four j zone contact at critical sealing areas of the container.
~ .ore specifically there is provided a closure made of a plastic material comprising a top, a skirt depending from the top, and means on the skirt for securing the closure over the discharge opening in a container and the container finish at the discharge end of said container, the improvement com-prising sealing means formed integrally with the closure and depending from the inside surface of the top consisting of a pair of inner and outer circumferentially extending rela-tively flexible flanges projecting axially from the top a predetermined depth, each of said flanges having a sealing face disposed angularly relative to the top adapted to engage the container finish at radially spaced inner and outer zones, at least a pair of radially spaced, circumferentially extending ~0 ribs intermediate said flanges projecting axially from the top a depth less than that of the flanges and having a sealing face engageable with the finish at a zone intermediate said inner and outer zones.

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~1 BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and features of the invention will be more readily understood from a consideration of the jl following detailed description, ~aken in connec~i.on with th~
1~ accompanying drawin~s, in wllich:
~j Fig. 1 is a side elevational view of a closure in ¦ accordance wlth the present invention applied to a cOTItainer;
Il Fig. 2 is a fragmentary sectional view of the linerless j, closure;
10 ¦I Fig. 3 is a sectional view taken on lines 3-3 of Fig, 1 showing thè position oE the sealing means engaging the finish on thé container ~/hen t~le closure cap is ful.ly seated;
Fig. 4 is an enlarged fraglllentary sectional vie~ showi.n~
the angular disposition of sealing flanges and ribs of the , closure cap;
Il Fig. 5 is a sectional vJ.ew of t-l-e container closure 1~ axsemhly of Fig. 3 showing the closure as initially applied Il to the container;

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,I Fig. 6 is a sectional view of a container closure asseTn~
bly in accordance with the presen~ invention with the closure ¦ shown in a sealed or seated position; and Fig. 7 is a sectional view of the container closure assembly o~ Fig. 6 showing the closure as initially applied ~, to the container.
'I DESCRIPTION OF SPECIFIC EMBODIMENTS
There is illustrated in Figs. 1 and 3 a closure cap 10 in ac~ordance with the present invention adap~ed to be applled over the discharge opening 12 in a container 14. The closure Il cap 10 is o~ cup-like form including a generally disc-like top ¦l 16 having a skirt 18 depending rom its outer periphery. ~.on- ¦
~ ventional screw threads 20 are formed on the inner periphery of ¦
`~l the skirt which cooperate with a conventianal screw thread 2~ ¦
! on the exterior wall of the neck 24 of the container to permit ~,¦ application and removal of the cap 1~ simply by rotating th~
cap 1~ relative to the container 14. The skirt 18 includes a series o~ smaIl longitudinally extending circumerentially ¦¦ spa~ed ribs or knurls 26 facilitating gripping during applica-¦ ~on and removal of the cap 10. The cap is adapted to.be ~
¦I molded by conventional process of a semi-rigid plastic material, ¦ such as polypropylene. The container as illastrated is made of glass, but may also be made of other materials.
In the present instance the cap 10 includes sealing ¦I means broadly designated by the numeral 32 which in the seated or locked position engage the finish 34 of the container. In 6~

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the prese~t instance ~hb ~inish comprises a flat radial wall section 34a and an ~nwardly and downwardly converging frustQ-conical wall section 34b. The wall section 34b 13 preerably convergent at an angle of abou~ 45 ralative to ~he p~a~e of the radial wall sec~ion 34a. The sealing means comprises a series o~ radially spaced, circumeren~ially extending sealin~
flanges and ribs depending from the inner ~ace o~ the top of the ~losure and spaced radially inwardly ~om the sid~ wal~
~o that they enga~e and seal wi~h ~h~ container fini~ e 1~ ~eated or locked p~sitlon in the manner illustxa~ed in Fig. 3.
In the illustra~ed embodiment o~ ~he invention~ ~h~ series includes ~nnex and oute~ sealing 1anges 36 a~ 38 o~ gener-ally triangular cro~ section and of a predetermined axial pro~ectlon or depth ~1 and a pair of intermediate sealing ribs 40 and 42 of a shortex axial depth H~ than ~he inner and outer ~lange~ 36, 38. Each o the 1anges and xibs has a seal-ing ace which engages the container finish in the seated position at four spaced zones, an inner zone Zl at the wall sect~on 34b, an outer zone Z2 at the oute~ xim 46 and inter-mediate zones Z3 and 24 at ~he wall section 34a. Tests, dis-cussed below, have demonstrated that the improved and sim-pliied one-pieee line~less closure provides an ef~ective seal with a markedl~ reduced evapora~ion loss when used on containexs for li~uid products. Tests also demonstrate that removal torques are in a range permitting easy removal of the cap even a~ter a significant storage pexiod. It will be observed ~urther that the removal torque remains uniorm even a~ter a signi~icant storage period providing uxther evidence of seal integrity.
'I~ is believed that the speoific con~ ration o~ the sealing ~la~ges and ribs and disposition ~elative to the con-tainer ~inish are impor~ant factors in providing ~he improved .

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sealing characteristics of the closure of the pxesent invention.
Thus, the inner sealing flange 36 which projects generally in an axial direction from the top has a circumferential inner wall 36a, generally perpen~icular to the top, a frusto-conical sealing face 36d, which diverges downwardly and inwardly from the top to a feathered edge or tip 36c. The sealing face 36b is preferably disposed at an angle of about 25 to the trace of the inner wall 36a or about 65 relative to inner surface 16a of the top. This shape provides the rib with a degree of rigidity at its base adjacent the top and a degree of flexibil-ity at its point of contact with the chamferred wall section 34b of the container finish. The outer sealing flange 38 like-wise has a circumferential outer wall 38a extending generally perpendicular to the top and a downwardly and ~utwardlydiver~-ing frusto-conical sealing face 38b which terminates in a feathered edge or tip 38c. Preferably the an~le of taper of the sealing face 38b is about 20 relative to the trace of the outer wall 38a or about 70 relative to the inside surface 16a of the top. The axial depth Hl of the ~langes f~om the base to the tip is preferably about 0.053 inchesO
The central sealing elements comprise a pair of circum-ferentially extending, axially directed ribs 40, 42 depending from inside surface 16a of the top and located between the inner and outer sealing flanges 36 and 33. The sealing ribs 40 and 42 are of a generally triangular cross section and have inner and outer circumferential walls 40a, 42a confronting angularly oriented sealing faces 40b, 42b which merge with the circumferential walls in edges or tips 40c, 42c. The sealing faces 40b, 42b are disposed at an angle of approximately 60 relative to one another and as illustrated, each sealing face 40b, 42b projects at an angle o~ about 60 relative to the top surface 16a. The ribs 40, 42 depend from the top an axial depth H~ approximately hal~ of the projection of the flanges or about 0.030 inches. The inner wall 40a of the inner rib 40 is preferably disposed at an angle of about 10 relative to a circumferential surface of revolution Rl through the apex at the base of the flange 36 and rib 40 and perpendicular to the inside surface 16a of the top or about ~0 relative to surface 16a and describes an angle of approximately 35 relative to the sealing face 36b of the inner flange 36. The outer cir-cumferential wall 42a of the outer sealing llb 42 is preferably perpendicular to the top surface 16a, and is therefore disposed at an angle of about 20 relative to the sealing face 38b of the outer flange 38.
In order to provide the sealing relationship shown in Fig. 3 with a container having a chamferred finish of the type illustrated when the cap is initially applied (Fig. 5), the tip or edge 38c of the outer flange 38 is preferably disposed slightly outboard of the cylindrical trace 46a of the outer sidewall 46 of the neck of the container and the inner flange 36 is preferably disposed so that the tip 36c is aligned in-~0 board of the juncture 47 of the axial and tapered wall sec-tions 34a, 34b of the container. In other words, the diameter D
of the outer flange 38 at the edge 38c is slightly greater than the diameter D2 f the outer side wall 46 of the neck of the container adjacent the outer rim 46 and the diameter D3 of the inner flange 36 at the edge 36c is less than the diam-eter of the circular juncture 47 of the axial and tapered wall sections 34a, 34b. It is noted that the diameter D3 is greater than the diameter D5 of the inner side wall of the neck of the container. By this arrangement, as the cap is threaded onto the container, the outer sealing flange 38 is deflected slight-ly outwardly so that its sealing face 38b engages the rounded outer edge 46 of the container at the zone Z2 and the sealing _ 9 _ face 36b of the inner flange 36 engages the tapered wall sec-tion 34b at a point slightly below the juncture 47 of the axial wall portion and tapered wall sections at the zone Z

The sealing faces 40b, 42b of the ribs 40 and 42 deflect away ., .
I from one another in the manner illus-trated to provide circum-i' ferentially extending radially spaced seal cvntacts along the , top face of the axial wall portion 34a at zones Z3 and Z4.
, Figs, 6 and~7 illustrate a modi~ied form o~ container . finish for a linerless closure in accordance with the pr~sent ,l invention. The closure cap is identical to that described above ' and accordingly, the same reference mlmeral.s are used to iden-~,', ti~y parts thereof, In this embodiment, however, the finish iO '~
l., of the container 51 comprises a radi.ally disposed axial end `~' surface 52 having inner and outer rims S4, 56 defined by ., rounded corners mergi.ng with the inner ar~(l outer ~.,idewal.ls ~i 58, 60 of the neck of the container, The closure cap in this instance is designed so that in the relaxed state prior to !1 3ppl, cation of the closure to the container and hefore seating i' thereof în the sealing position, the edge or tip 38c of the ,~, u~ flange is located slightly outboard o~ ~he outer sidew~li j ~1 oO of the container neck and the edge or tip 36c of the inner i ~lange aligns approximately at the mid point o~ the axial sur-li ~ace 52 of the con~ainer finish, In other words, the diameter !, Dl of the outer flange 38 at the edge 38c is slightly greater i` than the diameter D2' of the outer side~1all of the neck of the .. container adjacent the outer r;m 56 and the ~iameter D3 of tne inner flange 36 at the edge 36c is greater than the diameter D4' oi the inner sidewall 58 of tlle neck and, as Il ~
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, $~35 as illustrated, less than the diameter Dl. sy this arrangement 9 when the cap is rotated to a closed or sealed position, the I sealing face 38b of the outer flange 38 engages at approximately ii it~ mid point, the outer rim 56. The ribs 40 and 42 in this .; .
instance engage the surface 52 of the container finish at . radially spaced zones Z3 and Z4 and the inner flange is de-il flected to almost a radial attitude providing a relatively wide , inner sealing zone Zl adjacen~ the irner rim 5 Tests were conducted to determine product loss by ' evaporation in container closure assemblies in accordance with il the present invention and also to evaluate removal torque, In 1' ,l typical tests, quart containers were illed with 86% prool 'l ethanol (43% by volume) and sealed with a 28 mm closure5 the container finish and closure being o the type shown in Fig~
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a.ld 5. The closures were applied by autornati.c cappl.ng equip-l, ment set ~or an application torque of approxi.mately 2S in.-l.b~.
i, ~h~ container-closure assemblies were initially weighed and then placed on their sides in an oven ~set at 110F for a test period o~ 21 days, At periodic intervals~ e.g , 7 and 14 days, the containers were removed from the oven, placed in ambience fo 16 hours and weighed. In a significant number of the samples . tested, there was zerv or substantially no evaporation loss and the average was sig~ificantly below the liuqor industry standard ,; o~ .5 grams. The average removal torque remained substantially i;

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constant in a range of about 13.2 in.-lbs. for the entire time span of the tests for closures tested and were in a range between 12-15 in.~lbs. These torque levels were within accept-able limits. Uniformity i5, of course, desirable since it is indicative of seal integrity and also insures that the closures can be removed with compara~ive ease even after su~stantial storage periods. Similar tests were conducted with container-closure assemblies of the type shown in Figs. 6 and 7 and the results were within the ranges discussed above. Thus, while the invention has been described with particular reference to specific embodiments thereof, it will be understood that it may be embodied in a variety of forms diverse from those specifically shown and described, without departing from the spirit and scope of the invention as defined by the appended claims.

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Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OF PRIVILEGE
IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A closure made of a plastic material comprising a top, a skirt depending from the top, and means on the skirt for securing the closure over the discharge opening in a container and the container finish at the discharge end of said container, the improvement comprising the finish on the container including an outer radial wall section and an inner, inwardly con-verging frusto-conical wall section, sealing means formed integrally with the closure, depending from the inside surface of the top and consisting of inner and outer circumferentially extending relatively flexible flanges projecting axially from the top a predetermined depth, each of said flanges having a sealing face disposed angularly relative to the top, the sealing face on the outer flange being adapted to engage the container finish at a zone on the outer radial wall section, the sealing face on the inner flange being adapted to engage the inwardly converging frusto-conical wall section of the container, and at least a pair of radially spaced, circumferentially extending ribs intermediate said flanges and protecting axially from the top a depth less than that of the flanges, each rib having a sealing face engageable with the finish intermediate its engagement by said inner and outer flanges, said ribs having angularly disposed downwardly diverging confronting sealing faces.

2. A closure as claimed in claim 1 wherein the sealing face of the inner flange is disposed at an angle of about 65° relative to the inside surface of the top and wherein the sealing face of the outer flange is disposed at an angle of about 70° relative to said inside surface.

3. A closure as claimed in claim 1 wherein the sealing faces of said ribs are disposed at an angle of about 60° relative to one another.

4, The combination comprising a container having an opening, a finish adjacent the opening including a circumferentially extending outer edge portion, an inwardly converging frusto-conical wall section and at least a radially extending surface therebetween, a closure for sealing the opening in the container including a top, a skirt depending from the top, means on the skirt for securing the closure over the opening in the container, sealing means formed integrally with the closure and depending from the inside surface of the top consisting of inner and outer radially spaced, circumferentially extending relatively flexible flanges projecting axially from the top a predetermined depth, said inner flange having a frusto conical first sealing face disposed angularly relative to the top and projecting downwardly and inwardly therefrom at a predeter-mined angle, said outer flange having a second sealing face disposed angularly relative to the top, at least a pair of radially spaced, circumferentially extending ribs intermediate said flanges projecting axially from the top a depth less than that of the flanges, one of said ribs adjacent said outer flange having a third sealing face projecting downwardly and outwardly relative to the top and said other rib adjacent the inner flange having a fourth sealing face projecting downwardly and inwardly at a predetermined angle relative to the top, the sealing faces of said flanges and ribs adapted to engage the container finish at at least four circumferentially extending, radially spaced zones when the closure is assembled to the container to provide an effective moisture barrier for the contents of the container, with the sealing face of the inner flange engaging the inwardly converging frusto-conical wall section of the container.

5. The combination as claimed in claim 4 wherein said sealing surfaces of said ribs are angularly disposed relative to one another by an included angle of approximately 60°.

6, The combination as claimed in claim 4 wherein the sealing face of said outer flange is disposed at about an angle of 70° relative to said inside surface and wherein said sealing face of said inner flange is disposed at an angle of about 65° relative to the inside surface of the top.