CA1097262A - Plastic cap and container construction - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A plastic container has a neck formed with a substantially horizontal flat top. On the inside of the neck proceeding down-wardly there is a substantially vertical first sealing surface, then a top groove, then a very smooth second sealing surface of less diameter than the first sealing surface terminating in a lower groove and then a vertical stretch which merges into a breast which widens out to the full size of the container. On the outside of the neck proceeding downward from the flat top is a first vertical surface terminating in a horizontal inwardly extending shoulder below the elevation of the top groove, then an indented second vertical surface of lesser diameter than the first vertical surface and then an external bead having an outward-downward slanted top surface and a bottom horizontal inward-directed second shoulder at about the level of the lower groove, then a third vertical surface at about the level of the vertical stretch. The container is blow-molded or injection molded and, except at the top of the neck, where it is thicker, has a substantially uniform wall thickness. However, the second sealing surface has an "injection finish" obtained by use of a blow pin in the mold. The cap is an improvement on that shown in U. S. Patent No, 3,338,446. The upper and lower internal beads (which seat under the first and second shoulder of the neck) are interrupted in a plurality of gaps, permitting stretching of the cap to seat on the neck. The top disc has a peripheral flange which may be gripped to lift the cap when the bottom of the skirt is torn off. However the flange is flexible, bending to prevent prying off the cap when the skirt is intact.

Description

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This invention relates to a new and improved plastic cap and thin-walled cont~iner construction.
According to the invention, there is provided a cap having a central top disc, a thin-walled substantially cylindrical outer skirt of substantially uniform thickness depending from the periphery of said disc, said outer skirt being scored and weakened in a circumferential first line spaced downwardly from the top of said outer skirt and in a second line joining said first line and extending down to the bottom edge of said outer skirt, a tab attached to the bottom edge of saia outer skirt adjacent said second line, an upper internal circumferential bead on said outer skirt between said irst line and said disc, a lower internal ~ ~;
second bead on said outer skirt below but adjacent said first line, both of said beads being interrupted in a series of gaps spaced around the circumference of said outer skirt forming bead sections, thP sections of said upper bead b tween interxuptions being substantially shorter than the sections of said lower bead between interruptions.
With reference to the contain~r constructlon, a ` thin-walled light_weight plastic container of a material such as polyethylene which is inexpensive to manufacture is disclosed. A feature of this container is the fact that it may be blow~moulded but in~ection moulding may be used. When blow-moulded a smooth pin is inserted in the in~ide of the neck to provide an extremely accurate dimension in vertical sealing surfaces which are spaced downward from the top of the container neck. Further, as a result of the blow moul-ding process, the external dimensions of the neck are quite ~ 20 accurate. Hence r a liquid-tight seal is possible with a cap -~ of the construction hereinafter described wherein the seal is tight in the accurate sealing surface of the interior of the neck and also at the top or lip of the neck and at least

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one external surface of the neck. Further, accurately spaced shoulders are provided for gripp:ing the cap in i~i-tial condition but also when the lower portion of the skirt is torn in accordance with the teaching of U. S. Patent No.

3,33~,4~6.
The accuracy in the surfacas heretofore mentioned has not heretofore been achieved with blow moulded bottles without expensive finishing steps after moulding. Hence, the cost of fabrication of the bo~tle as well as the cost of the materials (by reason of the thin-wall construction) i8 considerably reduced over conventional practice.
A bumper ring may be formed below the necX to per-mit loading the bottles into boxes or crates by grippers without contacting the cap. ~ence, displacement of the cap during loading is avoided.
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The cap skirt may be shorter because a good seal -:
~ is achieved over a smaller area of contact because o~` the i ~
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accuracy of the moulding of the sealing surfaces of the container neck.

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~'urt,her~ with respect to the cap, the locking bead~, which are located immediately above and below the horizontal tear line o~ the cap, are interrupted~ InterruptioTI o~ the bead makes it possible ~or the skirt to stretch when the cap is being installed on the bottle neck in a conventional capping machine. Hence~ the ~orce required to seat the oap on the neck is lessened and this materially reduces the tendency o~ the neok o~ the bottle to be crushed or deforTaed during capping. Further~ it pe:rmits the bottle walls to be made thinner since crushing ~orce is reduced~ ::
It will be seen that khe structure o~ the cap and o~ the con-tainer neck cooperate to make possible the advantages of each;
and more particularly, that the structure of the Gap permits use with a thinner and rnore flexible container wall, yet permits the cap to be applied wi-th conventional machinery or by hand, When the~bottom o~ the skirt below the soore line is torn of~, the upper part o.~ the cap is used ~or reclosure. A periph-, .
eral f1ange o~ the top disk is provided for prying O~r the re-~:~ clo~ure cap~ This flange is thin and bendable so that when the ~ skirt is intact and an e~fort, is rnade to pull of~ the cap, the :. 20 Mange will ~lex9 thwarting e~ortæ to tamper with the contents : ~:
of the containerO
Many o~` the advantages of U, S. Patent 3,338~4L~6~ on which ;;
this invention is an improvement, are incorporated in the present structure, For sake o~ brevity, these advantages are not repeat-ed, but reference is made to the aforernentioned patent.
~: Other objects of the present invention will becorne apparent upon reading the following specification;and referring to the accompanying drawings in which similar characters of re~erence represent corresponding parts in each of the several views~
In the drawings:
Fig. 1 is a fragmentary side elevational view o~ a cap in accordance with tho present invention and a container neck~
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Fi~. 2 is an enlarged vertical sectional view oP the 5 tructure of F`ig. 1~
Fig~ 3 is an e.~ploded view of the structure of' ~ig. 2 show-ing the cap and con-tainer neclc disassembled~
Fig. L~ is a side elevational vlew o.~ a cap in accordance with the invention with the tear strip partially torn off to reveal lnternal construction o~ the cap skirt.
Fig. 5 is a schematic view of the interior of the outer cap skirt developed in a plane to show the interruptions o~ the upper and lower locking beadq.
The present invention comprises improvements over U.S. Patent 3~338~L~46 both in the cap 11 and container 12~ For convenienoe, the cap will be rirst described~
Cap 11 comprises a top disc 16 having a planar undersurface, Depending ~rom the underside of disc 16 is an interior skirt 17 :~ which is relatively short and has an outwardly-downwardly slanted ~: inne.r wall 18, a substantially vertical outer wall 19 and an ~:~
~: inwardly-downwardly tapered edge 20 which merges with the lower edge o~ wall 18~ ~
Outwardl~ spaced ~rom the inner skirt 17 is outer skirt 21 which has a ~ubstantially vertical outer wall. Considering the inner:wall o~ outer skirt 21, extanding down~from disc 16 is a substantially vertical top str~etch 22 o~ a length about equal to ; that of inner skirt 17~ which terminates in an internal bead 23.
Below bead 23 is an intermediate vertical wall 21~. which termi-nates in an internal lowar bead 2h, Bead 26 has a slightly downward-irlwRrd slanted top sur~aoe 27 which merges with a sub-stantially downwardly-outwardly inclined lower surface 28~ As i9 best shown in Fi.g, 5~ beads Z3 and 26;are not ccntinuous (i.eO, : 30 are not circum~erential) but are interrupted with a plural.ity o.
gaps 36 and 29, respectively. Hence, the wall thickness o~ the skirt 21 at the gaps 36 and 29 is considerably thinner than at the bead sections 23~ 26. This permits stretch:ing o~ the skirt - , during capping1 as has herctoeore been exI)la1nod. The u~p~r bead secti.ons 37 between gaps 36 are shorl; and are about equal to the lengths of gaps 36. The lower beacl sections 30 are con siderably longer than sections 37 (about '3iX time3 as long).
The long sections 30 prevent cap remova`l when the skirt is in-tact. The short sections 37 assist easy removal of the reclo-sure cap 39 hereina~ter described~ Spacecl immediately abo~e the top surface of bead 26 is a horizontal groove rormed on the lnterior o~ skirt 21 to per~it tearing. Extending upwardly in a slightly spiral configuration is spiral groove 32 which extends from the botto~ edge 33 o~ the outer skirt 21 to mcrge with the horizontal scoré line 31. A tear tab 31~ which may be easily gripped with the fingers depends from the lower edge of skirt 33 immediately to one side of spiral groove 32. To facilitate gripping tab 3~ transverse ridges 35 may be formed thereon~
-- It will be noted that the upper sdrfaces 27 of bead sections 26 ~ are spaced slightly downwardl~ ~rom the horizontal groove 31~
:~ A~ter the lower portion o~ the skirt is completel~ torn off there is a reclosure cap 39 above what was formerly the groove 31 which may be used to recap the container, as is explained in U. S. Patent 3,338,4L~6. A thin, flexible peripheral ~lange 4L
o~ top disk 16 may be used to pull reclosure cap 39 off. 1low-e~er, when the outer skirt 21 is intact9 flange 41 will flex -(see Fig. 1), thwarting efrorts to tamper with the~contents of the container~
Directing attention now to the neck of container 12, at the top is a horizontal inwardly turned flange 51 having a substan-tially ~lat top sur~ace 52 dimensioned to fit against the under-side of disk 16 between the inner skirt 17 and outer skirt 21.
Describing, first, the interior sur~ace of neck 12, proceeding downwardl~ ~rom horizontal surface 52 at a substanti.ally right angle thereto is a short first sealing surface 53~ Below surface 53 there is a groove 54 separating sur~ace 53 from the second ..
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saal;ng surf`ace 5'6 whlch is o~ lesser d:i~meter than tho surrac~
52~ In the molding Or the neck 12 a smooth pln is inserted which accurately ~orms smooth sur~aoes 53 and 56. Sur~aces 53, 56 seat against inner skirt sur~ace 19 causing it to bend slightly out-ward and ~orm li~uid -tight seals. Below sur~ace 56 i9 a second outward-extending groov0 57 and below groova 57 is lower vertical surfaca 58 which is of 'lesser diameter than surface 56. ~elow surface 58 9 the interior wall 5~ of the breast Or the neck ex-tends. In a preferred shape there is a bumper ring 72 which receives grippers of auto~atic loading equipment~ Thus tha grippers do not engage Cflp 11 and impair the seal.
It will be seen that the wall thicknesses of the neck 12 are substantially uniform throughout and ara thinner than other plastic container necks of this general type.
D;recting attention now to the exterior of neck 12, extend-ing vertically downward from surfaca 52 is an external~irst ~; vertical surfaca 61 whi'ch tarminates at a sharp angle with .
horizontally-inwardl~ extending shouldar 62. The length Or ' surfac0 61 is such that the bead 23 of the cap in assembled cond:ition seats immediately under shoulder 62 and holds the cap in placeg even when the score line 31 has bean torn. Thus ; the bead 23 and shoulder 62 keep the reclosure cap 39 in placa.
Below shoulder 62 is second vertical surface 63 which is of sub-stantially lesaer diameter than surface 61. ~urface 63 termi-nates in external 'bead 64~ Baad 6l~ has an outward~y-downwardly ~' slantad upper surfaca 66 (ab about 35 with tha horizontal and approximatel~J parallel to surface 28) which i5 rounded and mergas with lower horizontal shoulder 67. Interrupted b~ad sections 30 seat immediataly under shoulder 67~ Below bead 6l~ there is a third v,ertical surface 68 which than marges with the external surface 69 of the breast.
In the assembly of the cap 11 on tha neck 12 (i.e~, tha downward movement o~ the cap 11 from the position o~ Fig~ 3 to the seated posltion of Fig~ ~), the skirt 21 stretches to per-mît the slanted sur~ace 28 Or lower bead 26 to slide over first the co.rner where the surrflces 52 and 61 intersect and then to slide over bead 6L~. S:imllarly, the rounded bead 23 slides over said corner and surface. In the seated position o~ Fig. 2~ the bead 23 is seated under the shoulder 62 and the bead 26 is seated under the shoulder 67. There i3 a tight liquid seal between the external wall 19 of the inner skirt 17 and the sur~aces 53 and 56, which have been stated to be extremely smooth~ Surface 52 seats against the underside of disc 16 and surfaces 61 and 22 accurately seat together. Hence an e~tremel~ liquid-tight seal results.
Until the outer skirt 21 is torn, the cap ll cannot be removed from the bottle neck 12 without deforming the neck 12.
Hence tampering with the contents of the contalner is easily :
detected. Flaoge L~l fl:e~es3 as shown i~ Fig. l~ to prevent prying off the cap~
When the user wishes to open the container, he first grips the tab 34 and pulls upwardLy and to the left as viewed in Figs:.:
l and 4, causing the skirt to tear along the spiral groove 32 The user then pulls the tab 34 outwardly away from the neck 12 :~
causing the skirt to tear along the groove 31 so that the entire ~.
tear strip below the groove 31 is remo~ed. To open the bottle, the user then pries up on the flanee 41 causing the bead 23~to snap outside of the shoulder 62. Reclosure is performed merely by pushing downward on the cap ll until the be~d 23 seats mder the shoulder 62.

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Claims (5)

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

1. A cap having a central top disc, a thin-walled substantially cylindrical outer skirt of substantially uni-form thickness depending from the periphery of said disc, said outer skirt being scored and weakened in a circumberen-tial first line spaced downwardly from the top of said outer skirt and in a second line joining said first line and exten-ding down to the bottom edge of said outer skirt, a tab attached to the bottom edge of said outer skirt adjacent said second line, an upper internal circumferential bead on said outer skirt between said first line and said disc, a lower internal second bead on said outer skirt below but adjacent said first line, both of said beads being interrupted in a series of gaps spaced around the circumference of said outer skirt forming bead sections, he sections of said upper bead between interruptions being substantially shorter than the sections of said lower bead between interruptions.

2. A cap according to Claim 1, which further comprises a short inner skirt depending from said top disc spaced inward from said outer skirt.

3. A cap having a central top disc, a thin-walled substantially cylindrical outer skirt of substantially uni-form thickness depending from the periphery of said disc, said outer skirt being scored and weakened in a circumferen-tial first line spaced downwardly from the top of said outer skirt and in a second line joining said first line and ex-tending down to the bottom edge of said outer skirt adjacent said second line, an upper internal circumferential bead on said outer skirt between said first line and said disc, a lower internal second bead on said outer skirt below but adjacent said first line, and a thin flexible peripheral flange projecting out from said outer skirt near the top of said cap, said flange being manually engageable to pry off said cap only when said outer skirt below said first line has been torn off, said flange flexing when pulled to prevent use of said flange to pull off said cap when said outer skirt below said first line has not been torn off.

4. In combination a cap having a central top disc, a thin-walled substantially sylindrical outer skirt of sub-stantially uniform thickness depending from the periphery of said disc, said outer skirt being scored and weakened in a circumferential first line spaced downwardly from the top of said outer skirt and in a second line joining said first line and extending down to the bottom edge of said outer skirt adjacent said second line, an upper internal circumferential bead on said outer skirt between said first line and said disc, a lower internal second bead on said outer skirt below but adjacent said first line, a thin flexible peripheral flange projecting out from said outer skirt near the top off said cap, said flange being manually engageable to pry off said cap only when said outer skirt below said first line has been torn off, said flange flexing when pulled to prevent use of said flange to pull off said cap when said outer skirt below said first line has not been torn off, and a short inner skirt depending from said top disc spaced inward from said outer skirt and a container formed of thin-walled, plas-tic material having a cylindrical neck, said neck having an inturned top flange with a flat, horizontal lip, said flange terminating in an internal first substantially vertical sea-ling surface, a groove below said first sealing surface, an internal, smooth second vertical surface below said groove sealing against the exterior of the lower end of said inner skirt, said second surface being of lesser diameter than said first surface, a first external neck bead, a second external neck bead on the exterior of said neck vertically spaced from said first bead, each of said neck beads having a substantially horizontal shoulder on its lower edge, said inner skirt sealing against said first and second sealing surfaces, said lip sealing against the underside of said disc, said first and second beads of said cap seating under the horizontal shoulders of said first and second neck beads, respectively.

5. In combination, a cap having a central top disc, a thin-walled substantially cylindrical outer skirt of sub-stantially uniform thickness depending from the periphery of said disc, said outer skirt being scored and weakened in a circumferential first line spaced downwardly from the top of said outer skirt and in a second line joining said first line and extending down to the bottom edge of said outer skirt, a tab attached to the bottom edge of said outer skirt adjacent said second line, an upper internal circumfernetial bead on said outer skirt between said first line and said disc, a lower internal second bead on said outer skirt below but adja-cent said first line, at least one of said beads being inter-rupted in a series of gaps spaced around the circumference of said outer skirt, and an inner skirt, and a container for-med of thin-walled, plastic material having a cylindrical neck, said neck having an inturned top flange with. a flat, horizon-tal lip, said flange terminating in an internal first substan-tially vertical sealing surface, a groove below said first sealing surface, an internal, smooth second vertical surface below said groove, said second surface being of lesser dia-meter than said first surface, a first external neck bead, a second external neck bead on the exterior of said neck verti-cally spaced from first bead, each of said neck beads having a substantially horizontal shoulder on its lower edge, said inner skirt sealing against first and second sealing surfaces, said lip sealing against the underside of said disc, said cap having thin, flexible peripheral. flange projecting out from the top of said outer skirt, said flange being manually en--gageable to pry off said cap only when said outer skirt below said first line has been torn off, said flange flexing when pulled to prevent use of said flange to pull off said cap when said outer skirt below said first line has not been torn off.