GB2303119A

GB2303119A - A collapsible container

Info

Publication number: GB2303119A
Application number: GB9514210A
Authority: GB
Inventors: John Winston Harvey
Original assignee: Courtaulds Packaging Ltd
Current assignee: Albea UK Ltd
Priority date: 1995-07-12
Filing date: 1995-07-12
Publication date: 1997-02-12
Anticipated expiration: 2015-07-12
Also published as: GB9514210D0; GB2303119B

Abstract

A square or rectangular cross-section collapsible flexible container has an outlet nozzle 28 projecting from rectangular or square cross-sectional shoulders 27. The nozzle is closable by a non-circular double walled cap 35, a snap fit engagement occurring between an inward internal projection 38 of the cap and a radially outward projection 32 of the nozzle, to restrict axial movement of the cap 35 from the nozzle 28. External walls 37 of the cap have the same cross-section as the shoulders 27, which have cam surfaces 34. Rotation of the cap 35 relative to the shoulders causes the cam surfaces to move the cap away from the shoulders 27 and disengage the cap 35 from the nozzle 28. To form the container, a shoulder piece 21 is welded to a square cross-section tubular body 15B which has been formed from a flat ribbon with a longitudinal seam adjacent a corner of the body.

Description

A Collapsible Container This invention relates to containers and in particular to flexible containers for extrudable viscous products such as toothpaste. Collapsible flexible containers in which viscous products are stored, and from which the product may be extruded through a cap-closed nozzle, are well known.

Such tubes are generally of round cross-section and at the end remote from the cap are sealed by a folded flat closure.

A problem with such tubes is that they are not easily stacked and as a consequence are usually contained within cartons. In order to reduce the expense of this extra packaging it has been proposed in US Patent 5,373,965 to provide square cross-section tube for such containers.

In US Patent 5,299,689 there is proposed a blow moulded square cross-section tube having a closure cap with a flat top surface so that the tube can be stored vertically on its cap.

The present invention provides a container with a pushon/twist-off closure cap which is particularly useful for a container having a square section flexible body.

Accordingly there is provided a square or rectangular cross-section flexible container having an outlet nozzle projecting from rectangular or square cross-sectional shoulders, the nozzle being closeable by a non-circular cap which has a snap fit engagement with the nozzle to restrict axial movement of the cap away from the nozzle whilst permitting relative rotational movement therebetween, the cap having sidewalls that are proximate to the shoulders when the cap is engaged with the nozzle, the shoulders having cam surfaces thereon so that rotation of the cap relative to the shoulders causes the cam surfaces to move the cap away from the shoulder and disengage the cap from the nozzle.

The snap fit engagement is conveniently provided by the cap being formed of a plastics material and having at least one radially inward projection thereon that is engageable with detent means, preferably at least one radially outward projections on the nozzle.

The radially inward projection is preferably in the form of an annular rib which is resiliently expandable to pass over the or each projection on the nozzle.

Preferably the annular rib has a frustoconical surface on its side engageable with the or each projection on the nozzle, and preferably the or each projection on the nozzle has an inclined upper surface and a flat lower detent surface normal to the longtudinal axis of the nozzle.

The terms 'upper' and 'lower' as used herein are relative to the shoulder, the upper surface being further from the shoulder than the lower surface. The cap is preferably a double walled cap with an external wall having a crosssection substantially similar to that of the shoulders, and an internal wall which is cylindrical and has at least one radially inward projection thereon for engagement with the nozzle.

Preferably the shoulders are inclined and the cam surfaces are formed on the shoulders in lines interconnecting the central axis of the nozzle to the corners of the shoulders, and the external sidewalls engage these cam surfaces as the cap is rotated relative to the shoulders causing the cap to disengage from the nozzle.

The cap may be provided with a flat end wall, which could be used for standing the container upright on a horizontal support surface.

Preferably the container has a square cross-sectional flexible tubular body which is welded to the shoulder, and which is formed by rolling up a flat ribbon of material, in particular a ribbon formed from laminated layers of different materials.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figures 1A and 1B are a schematic view showing the manufacture of square tubes for a container according to the present invention, Figure 2 is a longitudinal view of a container according to the present invention, shown without a cap and sectioned below the centre-line, Figure 3 is a plan view of the shoulder piece of the container of Figure 2, Figure 4 is a part sectional view through the shoulder piece taken along the line IV-IV of Figure 3, Figure 5 is a longitudinal view of the nozzle end of the container of Figure 2, showing a closure cap assembled over the nozzle of the shoulder piece, also partially sectioned, and Figure 6 is a view of the cap of Figure 5 seen from below.

With reference to Figure 1 there is shown, in schematic form, a process for the manufacture of square cross-section toothpaste tubes from a flat flexible plastics strip 10 typically having a thickness of between 0.3 and 0.5 mm. The strip 10 is typically a laminate of several layers of different plastics materials including a vapour-impermeable barrier which again may be a plastics material or a layer of aluminium foil.

The strip 10 is fed to a shaping funnel 11 which gradually brings the longitudinal edges 12 of the strip together with some overlap as the strip is advanced.

The rolled-up strip 10 passes over a generally cylindrical mandrel 13 and the overlapping edges 12 are welded together using a high frequency welder 14. The thin walled round tube 15 thus formed is next shaped into a square crosssection flexible tube 15B.

The round tube 15 is formed into the square tube 15B by separately flattening the tube 15 in two mutually perpendicular planes to form four folds or creases which correspond to the corners of the square tube. The round tube 15 is first passed between an upstream pair of rollers 16 which are arranged with their axes substantially vertical and then passes into the nip created between a second pair of rollers 17 which are arranged with their axes substantially horizontal.

The tube 15 is cut to the required length necessary by a knife 19. The knife 19 is arranged so that the cut end of a length of tube has engaged with the second pair of rollers 17 before the knife severs that length from the continuous tube 15.

When the tube 15B is formed, the welded overlapping seam is conveniently arranged so that it is adjacent to a corner crease or fold Referring now to Figures 2 to 4, the square cross-section tube 15B has a shoulder piece 21 located at one open end of the tube 15B. The other end of the tube 15B is closed, after filling the tube with the material (e.g. toothpaste) to be stored therein, in a fish-tail type welded seam 22.

The shoulder piece 21 is suitably moulded in one piece from a high density polyethylene material.

The shoulder piece 21 shown in Figures 2, 3 and 4 comprises a square lower side wall 23, having at its upper end a rounded shoulder 24 leading to a moulded step 25, an axially extending upper side wall 26, and an inclined flat pyramidal shoulder 27 that is inclined inwardly and away from the sidewall 23 and which terminates in a central nozzle 28. The sidewall 23 is a close fit within an end portion of the square tube 15B which, after the application of heat, is turned over the rounded shoulder 24, brought into abutment with the step 25 and then heat welded to the shoulder piece to form a peripheral leak-tight seal.

The nozzle 28 has an inwardly tapered external surface 29 which extends axially from a cylindrical neck 31.

The cylindrical neck 31 has four equiangularly spaced radially outwardly projecting lugs 32 thereon located one in alignment with the mid portion of each side of the square sidewall 23. Each lug 32 has an inclined upper surface and an undercut lower surface that in use acts as a detent. The neck 31 projects from a square plinth 33 which is spaced axially from the lugs 32. The plinth 33 has rounded corners and each side thereof is aligned with the radially outermost point on the respective lug 32.

The inclined shoulder 27 extends from the upper sidewall 26 to the plinth 33. The four inclined surfaces which make up the pyramidal shoulder 27 intersect along diagonal areas 34 of the square which are symmetrically located about radial lines struck from the longitudinal axis of the nozzle 28.

In Figure 5 the nozzle 28 is shown closed by a square closure cap 35 which makes a snap-fit engagement with the nozzle 28. The cap 35 may be moulded in one piece from high density polyethylene or polypropylene. The cap 35 is a double walled cap having an end wall 30 with an inner cylindrical wall 36 and an external skirt 37 of square cross-section extending axially therefrom. The skirt 37 has an external cross-section somewhat less than the crosssection of the lower side wall of the shoulder piece 21 but is a clearance fit over the upper sidewall 26 of the shoulder piece 21. The inner edge at the bottom of the skirt 37 is chamfered somewhat to aid rotation of the cap 35 relative to the shoulder piece 21 and facilitate its removal from the nozzle 28.

The cylindrical inner wall 36 of the cap has internal projection 38 on its inner surface adjacent to its lower free end portion. These projections may be in the form of an annular array of spaced ribs as shown, or a continuous annular rib. As illustrated in Figure 6 there are four spaced ribs each of which is in alignment with the mid portion of a respective sidewall that makes up the skirt 37 so that each rib is in alignment with a lug 32 on the nozzle 28 when the cap 35 is fitted over the nozzle. The lower surface of each rib is chamfered so that the projections 38 can ride up over the corresponding lug 32 when the cap is snapped onto the nozzle 28.

The end wall 30 of the cap is substantially flat allowing the filled container to be stood on the end wall 30 of the cap. The inner surface of the end wall 30 has an annular rib 39 which, in use, seals against the end of the periphery of the opening in the nozzle 28. The rib 39 could have a collapsible form such as a 'C' cross-section as in a crabsclaw seal, an inverse 'Y' section, or could be a bore seal designed to slightly enter the opening in the nozzle.

When the cap 35 is fitted over the nozzle 28, the projections 38 on the free end portion of the inner cylindrical wall 36 ride up the tapered face 29 of the nozzle, pass over the lugs 32 and snap-in behind the lugs 32 which then act as detents resisting axial separation of the cap 35 from the shoulder piece 21, whilst allowing the cap to rotate somewhat relative to the nozzle 28. In this condition the face ends of the skirt 37 either abut or are in close proximity to the rounded shoulder 24 on the shoulder piece 21.

It will be appreciated that for the square upper sidewall 26 and the square cap skirt 27, the radial distance between the rotational axis of the cap about the nozzle, and each mid sidewall is less than the radial distance to each corner. Thus if the cap is rotated to any significant degree relative to the nozzle, the skirt 27 will ride-up the sidewall 26 and over the diagonal areas 34 which act as cam surfaces causing the projections 38 to disengage from the lugs 32 allowing the cap to separate from the nozzle.

It will be appreciated that snap-fit engagement between the cap and nozzle could be achieved with lugs on the cap and a continuous rib on the nozzle, as well by means of interengaging continuous ribs on both the cap and the nozzle.

Claims

1. A square or rectangular cross-section flexible container having an outlet nozzle projecting from rectangular or square cross-sectional shoulders, the nozzle being closeable by a non-circular cap which has a snap fit engagement with the nozzle to restrict axial movement of the cap away from the nozzle whilst permitting relative rotational movement therebetween, the cap having sidewalls that are proximate to the shoulders when the cap is engaged with the nozzle, the shoulders having cam surfaces thereon so that rotation of the cap relative to the shoulders causes the cam surfaces to move the cap away from the shoulder and disengage the cap from the nozzle.

2. A container as claimed in claim 1 wherein the cap is made of a plastics material and has at least one radial inward internal projection thereon which is engageable with at least one radially outward projection on the outer surface of the nozzle.

3. A container as claimed in claim 1 or claim 2 wherein the cap is a double walled cap, having an external wall with substantially the same cross-section as the shoulders, and an internal wall which is cylindrical and has at least one internal projection thereon to engage with the nozzle.

4. A container as claimed in claim 3, wherein on rotation of the cap the external wall engages with cam surfaces on the shoulder, causing the at least one projection on the internal wall to disengage from the nozzle.

5. A container as claimed in any one of claims 1 to 4 wherein the shoulders are inclined so that they increase in height radially inwardly towards the nozzle, the cam surfaces engageable by the cap lying on radial lines extending from the axis of the nozzle to the corners of the shoulders.

6. A container as claimed in any one of claims 1 to 5 wherein the cap has a substantially flat end wall allowing the container to be stood on a horizontal support surface on its cap.

7. A container as claimed in any one of claims 1 to 6 wherein the cap has an inwardly projecting annular rib thereon, which is engageable with an annular array of spaced projections on the nozzle.

8. A container as claimed in any one of claims 1 to 7 wherein the shoulder is welded into one end of a flexible tube of square or rectangular cross-section.

9. A container as claimed in any one of claims 1 to 8, wherein the container has a square cross-section tubular body formed from a flat ribbon which has been formed into a square tube with a longitudinal seam where edges of the ribbon overlap, the longitudinal seam being adjacent a corner of the tubular body.

10. A container as claimed in claim 9 wherein the flat ribbon is a laminate which includes at least two polymeric based layers, and the container is used for toothpaste.

11. A collapsible container utilising a tube of square cross-section and a capped nozzle therefor substantially as herein described with reference to the accompanying drawings.