GB2306162A

GB2306162A - Closure assembly for a container

Info

Publication number: GB2306162A
Application number: GB9621175A
Authority: GB
Inventors: Richard John Wright; David Balkwill
Original assignee: Prelude UK Ltd
Current assignee: Prelude UK Ltd
Priority date: 1995-10-10
Filing date: 1996-10-10
Publication date: 1997-04-30
Also published as: GB9621175D0; WO1997013701A1; GB9520720D0

Abstract

A closure assembly comprises a cap or plug 38 and a container outlet 32 which have cooperating surfaces 34 and 39, either inside or outside the outlet, such that the cap or plug exerts a radial force on the container outlet. The cooperating surfaces may be frusto-conical and may be screw-threaded. The surfaces may incorporate annular lips or beads for sealing purposes. The container outlet may be made from a flexible material such as PVC, and may be provided with an external retaining ring (fig 9) to strengthen the outlet. The cap or plug may carry an openable enclosure (fig 8).

Description

CONTAINERS This invention relates to containers.

One method of forming a container is to produce a metal mould having an interior surface shape which is the exterior surface shape of the required container. Moulds of this kind are commonly made of copper. A liquid plastics material is then introduced into the mould which is rotated at speed in an oven so that the plastics material coats evenly the interior surface of the mould. When rotation has ceased, an end of the mould can be opened and the container withdrawn.

It will be appreciated that containers produced in this way need not be of generally cylindrical shape; they can have any required exterior shape. For example, containers can be produced that have the shape of a cartoon character or an object or a person.

Containers of such irregular shape are more difficult to remove from the mould. For this reason, they may be made of comparatively flexible plastics materials in order to ease removal.

Such containers require an outlet passage through which the contents can be dispensed (and through which the contents can be passed into the container). The outlet passage is closed by a removable cap which co-operates with the outlet passage to close the passage.

It is a problem with containers produced from such materials that, as the material hardens, it shrinks by an indeterminate amount. This mitigates against a proper seal between the cap and the outlet when the connection between the two is by conventional threads provided on cylindrical surfaces of the cap and the outlet. The outlet may shrink sufficiently to allow leakage.

According to the invention, there is provided a container including an elongate outlet passage and a cap for closing the outlet passage, the outlet having an interior surface and an exterior surface, the cap having a surface for co-operation with one of said outlet surfaces when the cap closes the outlet passage, said co-operation being such that the cap applies a force to the outlet passage in a direction normal to the length of the passage.

Thus, by shaping the surfaces1 the cap and the outlet can be squeezed into engagement with one another to provide an effective seal.

The following is a more detailed description of some embodiments of the invention, by way of example, reference being made to the accompanying drawings in which: Figure 1 is a partial cross-section through a first container and an associated cap, Figure 2 is a partial cross-section through a second form of container and associated cap, Figure 3 is a partial cross-section through a third form of container and associated cap, Figure 4 is a partial cross-section through a fourth form of container and associated cap, Figure 5 is a schematic view of a possible shape of the fourth container showing in detail a section through the container with a possible position for the cap, Figure 6 is a partial cross-section through a fifth form of container and associated cap, Figure 7 is a schematic elevation of a sixth container and cap, Figure 8 is a side elevation of a form of the container of Figure 5 including a transparent dome mounted on the cap, and Figure 9 is a partial cross-section through a further form of container and associated cap, the cap being shown separated from the container.

The containers now to be described with reference to the drawings are all formed by rotational moulding. This uses a copper mould whose interior surface is shaped to the required exterior surface of the container. A plug or plugs is or are provided at either end of the mould.

In use, a suitable plastics material is inserted into the mould which is then rotated at speed in an oven with the plastics material molten so that the plastics material spreads over the interior surface of the mould and conforms to its shape. When the plastics material has hardened, the plug or plugs are removed and the moulded container pulled from the copper mould. It will be appreciated that, if the shape of the container is complex, the plastics material needs to be sufficiently flexible to allow the container to deform on withdrawal.

The arrangements now to be described with reference to the drawings are most suitable for closing containers formed in this way.

Referring first to Figure 1, the first container 10 has a body 11 and an outlet passage 12. The passage 12 is generally cylindrical and has an exterior surface 13 and an interior surface 14. The interior surface 14 has (starting from the outlet opening at the exterior end) an initial annular portion 15 provided with a radially inwardly projecting annular triangular section lip 16. Although the lip 16 is of triangular section as shown, it could be of any suitable section. This portion 15 terminates in a radially inwardly directed step 17 and is followed by a second annular portion 18 of smaller diameter than the first annular portion 15 and provided with a thread 19. The thread 19 is a parallel thread.

The co-operating cap 20 has the general form of a hollow cylinder closed at one end and open at the other end. The outer curved surface of the cap has an initial cylindrical portion 21 whose diameter is generally the diameter of the annular portion 15 of the outlet passage 12. This terminates in a radially inwardly directed step 22 and is followed by a convergent portion 23 provided with a thread 24. The maximum diameter of the convergent portion 23 is greater than the diameter of the second annular portion 18 of the outlet passage 12.

When the cap 20 is used to close the container 10, the convergent portion 23 is inserted into the passage 12 and is pushed into the second annular portion 18 of the outlet passage 12 to engage the two sets of threads 19,24. Rotation of the cap 20 pulls the cap 20 down into the outlet passage 12 so drawing the cap step 22 past the lip 16 and into engagement with the passage step 17. The lip 16 thus is pushed radially outwardly by the cap 20 and engages around the cylindrical portion 21 of the cap 20 to form a seal.

In addition, the configuration of the second annular portion 18 of the passage 12 and the convergent portion 23 of the cap 20 is such that, when the cap 20 is fully tightened, the convergent portion 23 tends to expand the outlet passage 12 (which is formed of a flexible plastics material) by forcing it outwardly and so forms a tight seal between the convergent portion 23 of the cap 20 and the second annular portion 18 of the outlet passage 13.

Referring next to Figure 2, the second container 30 has a moulded body 31 formed as described above with an outlet passage 32 with an exterior surface 33 and an interior surface 34. The interior surface 34 is generally circular in crosssection and converges towards the interior of the container 30. This surface 34 is provided with a thread 35.

The inner end of the outlet passage 32 is provided with a radially inwardly directed annular flange 36 that surrounds a hole 37.

A co-operating cap 38 has a central portion 39 which is in the shape of a hollow truncated cone and is provided with a thread 40 on its outer surface for co-operation with the thread 35 on the outlet passage 32. The upper end of the central portion 39 is connected by a radially extending flange 41 to an outer depending wall 42 that can be gripped to turn the cap.

The dimensions of the central portion 39 are so chosen in relation to the dimensions of the outlet portion 32 that when the cap 38 is screwed into the outlet passage 32, the central portion 39 tends to apply a lateral force to the outlet portion 32 tending to expand the plastics material of the outlet portion 32. This provides a fluid-tight seal between the cap 38 and the passage 32.

In addition, the lower end of the central portion and the hole 37 are so sized that, when the cap 38 is screwed into the passage 32, this end projects through the hole and forces the flange 36 outwardly so that the end is gripped by the flange 36 so providing a further seal.

A shoulder 43 is provided between the upper end of the central portion 39 and the undersurface of the flange 36 to engage with the inner surface 34 of the outlet passage 33 at the outer end of the outlet passage 33. This forces the surface 34 outwardly and provides a further seal.

Referring next to Figure 3, the third container 50 is formed as described above and has an outlet passage 51 with an exterior surface 52 and an interior surface 53. The exterior surface 52 is generally frusto-conical with the diameter increasing towards the inner end of the passage 52. A thread 54 is provided around the exterior surface 52 and an annular rib 55 extends round the exterior surface 52 below the thread 54.

The outer end of the outlet passage 51 is provided with an annular radially extending wall 56 and an annular triangular section lip 57 extends around and projects outwardly of this wall 56 for a purpose to be described below. The outlet passage 51 also includes an annular converging wall 58 depending from the inner end of the flange 56 and formed at its inner end with an inwardly directed portion 59 surrounding a hole 60.

The co-operating cap 61 is of generally hollow frusto-conical shape with the wider end open and the narrower end closed by a wall 62. The inner surface of the cap is provided with a thread 63 which co-operates with the thread 54 on the outlet passage 51.

The end wall 62 of the cap 61 is provided with a central projection 64 which has a converging outer surface 65 terminating in an inwardly directed step 66 leading to a downwardly projecting plug 67.

As the cap 61 is screwed onto the container 60 by engagement of the threads 54,63, the projection 64 extends into the region surrounded by the wall 58. As the cap 61 is tightened down, the outer surface 65 of the projection 64 engages this wall 58 and the parts are sized so that the cap applies a positive lateral force to this wall 58 so sealing the parts together. In addition, the plug 67 enters the hole 60 to close the hole 60 and at the same time forces the portion 59 radially outwardly so providing a tight seal. The rib 55 engages the undersurface of the end wall 62 of the cap 61 and the rib 55 below the thread 54 engages the open end of the cap 61. All these measures increase the seal between the cap 60 and the outlet passage 61 to prevent leakage.

Referring next to Figure 4, the fourth container 70 has an outlet passage 71 with an exterior surface 72 and an interior surface 73. The exterior surface is generally cylindrical and is provided with a thread 74. An annular triangular crosssection rib 75 extends around the exterior surface 72 beneath the thread 74.

The outer end of the outlet passage 71 has an end wall carrying an annular triangular section lip 76 projecting in axial direction.

The interior surface 73 of the passage 71 has an initial convergent portion 77 terminating in a radially extending annular triangular cross-section rib 78.

The cap 79 is generally cylindrical and open at one end and closed at the other end by a wall 80. The wall 80 has a central depression 81 having a convergent frusto-conical outer surface 82. The opposite end of the cap 79 is provided with an outwardly directed flange 83. The interior of the cap 79 is provided with a thread 84 for co-operation with the thread 74 on the passage 71.

When the cap 79 is screwed onto the container 70, the depression 81 enters the convergent portion 77 of the interior surface 73 of the outlet passage 71. The parts are dimensioned so that as the cap 79 is finally tightened, the outer surface 82 of the depression 81 applies a positive lateral outward force to the outlet passage 71 so helping to form a seal between the parts. In addition, the lower end of the depression 81 passes the rib 78 at the end of the convergent portion 77 so that this rib seals against the outer surface 82 by forcing the surface 82 outwardly. In addition, the lip 76 seals against the undersurface of the wall 80 and the lower end of the cap 79 engages the rib 75 below the thread 74 to force the rib 75 outwardly to provide further seals.

The container 70 of Figure 4 shows the outlet passage 71 projecting from an upper end of the container 70. This need not be the case; as shown in Figure 5, an outlet passage 71 and cap 79 of the kind described with reference to those figures could be provided in the base of a container 90. In this case, the container 90 has a base wall 91 formed with a central depression 92 with the outlet passage 71 projecting from the centre of the depression 92 and the cap 79 in threaded engagement with the passage 71. The depression 92 is dimensioned so that the cap 79 does not extend beyond the plane of an outer peripheral portion of the base wall 91 in which the container 90 stands.

Such an arrangement (whether provided with an outlet passage and cap or with simply a moulded projection) can be advantageous in providing a portion that can be gripped when the end plug of a rotary die is open to withdraw the rotary moulded container. If the base wall of the container is flat, it can be difficult to grasp the moulded container and withdraw it.

Referring next to Figure 6, the fifth container 100 is provided with an outlet passage 101 which has an exterior surface 102 and an interior surface 103. The exterior surface 102 is frusto-conical with the diameter increasing towards the connection between the outlet passage 101 and the remainder of the container 100. A thread 104 extends around the exterior surface 102.

The outer end of the interior surface 103 is provided with a downwardly and outwardly projecting flange 105 with a convergent conical surface 106.

A cap 107 has an interior surface 108 which is frustoconically divergent and provided with a thread 109 for cooperation with the thread 104 on the outlet passage 101. The cap 107 is open at one end and closed at the other by an end wall 110 provided with a central plug 111 with a convergent frusto-conical outer surface 112.

As the cap 107 is screwed onto the outlet passage 101, the parts are dimensioned so that the cap 107 provides a positive lateral inward force on the outlet passage 101 to force the parts into sealing engagement. In addition, the outer surface 112 of the plug 111 engages the flange surface 106 as the cap 107 is finally tightened down and provides a lateral force against the flanges 105 and 106. This forms a further seal between the parts.

Figure 7 shows a modification of the arrangement of Figure 2.

The container 120 of Figure 8 is formed with an outlet passage shown in broken line at 121 which is substantially the same as the outlet passage 32 of the container 30 of Figure 2.

The cap of Figure 7 is, however, different from the cap 38 of Figure 2. In the container of Figure 7, the cap also comprises a rotary moulding 122 which can have any desired shape. For example, the container 120 could be in the shape of the torso of a person or animal and the moulding 122 in the shape of the head of that person or animal.

The moulding is formed integrally with a depending central portion 123 which is the same as the central portion 39 of the cap 38 of Figure 2. Thus, by rotating the moulding, the central portion 123 can be engaged with the outlet passage 121 as described above with reference to Figure 2.

The advantage of this arrangement is that both parts are formed by rotary moulding and there is, therefore, no need to use another moulding process for making a cap.

It will be appreciated that in those cases where caps are provided (Figures 1 to 4, 6 and 9), the cap 20,38,61,79,107 or 170 may carry a further part. For example, where the container 10,30,50,70,90,100 or 150 is in the shape of a body of a person or an animal, a moulded part shaped as the head of that person or animal may be fitted to the cap.

Another possibility is shown in Figure 8. In this case, the container 130 and the cap 131 are generally as described above with reference to Figure 4; although they could be as described above with reference to Figures 1 or 2 or 6.

The cap 131 has an outer surface 132 which is generally cylindrical and which is provided with a plurality of angularly spaced axially extending splines 133 of generally triangular cross-section. These engage with corresponding splines 134 provided on a cylindrical interior surface of a skirt 135 depending from a lower surface of a disc-shaped base 136. A flange 137 extends downwardly from the outer edge of the base 36 and terminates adjacent a shoulder 138 of the container 130. The flange 137 includes an annular outwardly extending step 139 which receives the lower edge of a transparent dome 140. The dome 140 forms an enclosure for an item 141 which rests on the base 36 and is located by a locating stud 142. The item 140 may be a moulded PVC character such as a person or an animal.

Referring to Figure 9, the container 150 shown in this Figure has a body 152 and an outlet passage 154. The passage 154 is generally cylindrical and has an interior surface 156 and an exterior surface 157. The interior surface has (starting from the outlet opening as shown in Figure 9) an initial annular portion 158 provided with a screw thread 160. The annular portion 158 terminates in a radially inwardly projecting annular generally triangular section lip 162, and is followed by a second annular portion 164 of smaller diameter than the first annular portion 158. The second annular portion 164 is terminated in a radially inwardly directed step 166 which is followed by a third annular portion 168 of a smaller diameter than the second annular portion 164. Although the lip 162 is of triangular section as shown, it could be of any suitable section.The third annular portion 168 may be omitted.

The outer end of the outlet passage 154 is provided with an annular triangular section lip 155 which extends around and projects upwardly of the outlet passage 154.

The exterior surface 157 of the outlet passage 154 is formed with an annular rebate 161. A retaining ring 163, formed from a material that is less flexible than the material of the outlet passage 154, sits in the annular rebate 161. This has the effect of limiting the radially outward expansion of the outlet passage 154, when the outlet passage 154 is closed by the cap 170 in a manner to be described below. Thus the retaining ring 161 limits the effect of the force applied to the outlet passage 154 by the cap 170.

The co-operating cap 170 has the general form of a hollow cylinder closed at one end 172 and open at the other end 174.

The cap 170 has (starting from the top as shown in Figure 9) an initial cylindrical portion 176 whose diameter is generally the diameter of the first annular portion 158 of the outlet passage 154.

The exterior surface 180 of the cylindrical portion 176 is provided with splines 182 extending parallel to the axis of the portion 176 from the first end 174 of the cylindrical portion 176 towards the second end of the cylindrical portion 176.

At a point on the exterior surface 180 of the cylindrical portion 176 below the termination point of the splines 182, the cylindrical portion 176 is provided with a radially outwardly extending flange 184. The flange has a diameter greater than that of the interior surface 156 of the outlet passage 154 of the container 150.

Furthermore, the top surface of the flange 184 is provided with axially upwardly extending ribs 186 lying in respective annularly spaced planes including the axis of the cap 170.

The ribs 186 are of generally the same diameter as the flange 184.

The cylindrical portion 176 is provided with a screw thread 188 at a point below the level of the flange 184.

The cylindrical portion 176 terminates in a generally frustoconical section 178 in which the minimum diameter of the frusto-conical section 178 is generally smaller than the diameter of the lip 162. The maximum diameter of the frustoconical section 178 is greater than the diameter of the lip 162.

When the cap 170 is used to close the container 150, the frusto-conical portion 178 is inserted into the outlet passage 154. The two sets of threads 160,188 are engaged and rotation of the cap 170 pulls the cap 170 down into the outlet passage 154. This action draws the minimum diameter portion of the frusto-conical section 178 through the third annular portion 168. As rotation of the cap 170 continues, the frusto-conical portion tends to force the triangular section lip 162 outwardly (which is formed of a flexible plastics material) and so forms a tight seal between the frusto-conical portion 178 and the lip 162.

The closed end 172 of the cap 170 may extend into the third annular portion 168 to force outwardly to further seal the outlet passage 154.

In both these cases, the outward expansion is limited by the retaining ring 163.

In addition, the configuration of the cap 170 is such that as the cap 170 is screwed into the container 150, the flange 184 is brought into engagement with triangular lip 155. The flange 184 forces the lip 155 radially outwardly providing a further tight seal.

The application of a positive lateral force to the outlet passage 154 by the cap 170 acts so as to seal the two parts.

This reduces leakage of fluids from the container.

The splines 182 on the cap 170 may engage a further part (not shown). For example, where the container 150 is in the shape of a body of a person or animal, a moulded part shaped as the head of that person or animal may be fitted to the cap 170.

It will be appreciated that in all the embodiments described above with reference to the drawings, there is contact between a part of the cap and a part of the inlet passage in which the cap applies a positive lateral force to the outlet to seal the parts. This reduces the incidence of leakage between these parts particularly when the container is formed of a plastics material that has variable shrinkage on cooling. In many embodiments, there is more than one seal. However, it will be appreciated that each of the seals may be used separately.

Claims

AIMS

1. A container including an elongate outlet passage and a cap for closing the outlet passage, the outlet having an interior surface and an exterior surface, the cap having a surface for co-operation with one of said outlet surfaces when the cap closes the outlet passage, said co-operation being such that the cap applies a force to the outlet passage in a direction normal to the length of the passage.

2. A container according to claim 1 wherein the outlet surface is the interior surface of the outlet passage, the cap, when closing the outlet passage, applying a force to the outlet passage in a direction normal to the length of the outlet passage.

3. A container according to claim 1 wherein the outlet surface is the exterior surface of the outlet passage, the cap, when closing the outlet passage, applying a force to the outlet passage in a direction normal to the length of the outlet passage.

4. A container according to claim 2 or claim 3 wherein the cap closes the outlet passage by screw threaded engagement with the outlet passage, said engagement applying said force.

5. A container according to claim 4 wherein at least one of said co-operating surfaces is frusto-conical, said threaded engagement forcing said frusto-conical surface into contact with the other of said co-operating surfaces.

6. A container according to claim 5 when dependent on claim 2, wherein the outlet passage interior surface is generally cylindrical and the co-operating cap surface is frusto-conical with a maximum diameter greater than the diameter of the outlet passage interior surface and minimum diameter less than the diameter of the outlet passage interior surface.

7. A container according to claim 5 when dependent on claim 3 wherein the outlet passage exterior surface is frustoconical and the co-operating cap surface is frusto-conical, said frusto-conical surfaces being so arranged as to produce said force when the cap closes the outlet passage.

8. A container according to any one of claims 5 to 7 wherein the co-operating surfaces are threaded surfaces which provide said screw threaded engagement.

9. A container according to any one of claims 1 to 8 wherein said outlet passage includes a threaded portion and the cap includes a co-operating threaded portion, the outlet passage surface being provided on a part of the outlet passage spaced from said threaded portion, the cap surface being spaced from the cap threaded portion.

10. A container according to claim 9 wherein the outlet passage surface is an exterior surface of the outlet passage, said surface including a circumferentially extending radially outwardly projecting bead for engagement with the cap surface.

11. A container according to claim 10 wherein said bead is of semi-circular cross-section.

12. A container according to claim 10 wherein said bead is triangular cross-section.

13. A container according to any one of claims 10 to 12 wherein the outlet passage includes an outlet opening at one end thereof, the threaded portion of the outlet passage extending around the exterior of the outlet passage, and said outlet passage surface being arranged beyond said threaded portion in a direction away from said end opening.

14. A container according to claim 9 wherein said outlet passage includes an outlet opening at one end thereof, said outlet passage surface being arranged adjacent said outlet opening on the interior of the outlet passage.

15. A container according to claim 14 wherein said outlet passage surface includes an annular lip extending around the interior of the outlet passage, the cap including an annular surface which seals against said lip when said cap closes the outlet passage to force the lip outwardly.

16. A container according to claim 15 wherein said lip is formed on an annular interior surface of the outlet passage which has a diameter greater than the diameter of said outlet passage threaded portion.

17. A container according to claim 14 wherein said outlet passage surface comprises a bevelled surface extending around said outlet opening, the cap including an annular shoulder engaging said bevelled surface when the cap closes the outlet passage.

18. A container according to claim 14 wherein the outlet passage includes, adjacent said outlet opening, an annular converging wall extending along the outlet passage from said outlet opening, the cap including a portion of generally frusto-conical shape which, when the cap closes the outlet passage, engages the annular converging wall to force the annular converging wall outwardly to provide a seal.

19. A container according to claim 18 wherein said the annular converging wall is formed around the interior of the outlet passage adjacent said outlet opening.

20. A container according to claim 18 wherein the outlet passage includes a frusto-conical part including said threaded portion on an exterior surface thereof, an annular converging member depending from an end of said threaded portion at said end opening and extending within the threaded portion, said annular converging wall being formed on said member.

21. A container according to any one of claims 18 to 20 wherein said annular converging wall terminates in an inwardly directed portion surrounding a hole, the cap including a portion entering said hole and forcing said portion outwardly.

22. A container according to claim 21 wherein the frustoconical portion of the cap includes a plug at the inner end of the frusto-conical portion, said plug entering the hole to close the hole and force the inwardly directed portion outwardly, when the cap closes the outlet passage.

23. A container according to claim 21 or claim 22 wherein said inwardly directed portion comprises an annular lip.

24. A container according to claim 9 wherein said outlet passage includes an outlet opening, the outlet passage threaded portion being adjacent the outlet opening and the outlet passage surface being on the interior of the outlet passage and following the threaded portion in a direction away from said end opening.

25. A container according to claim 24 wherein said outlet passage terminates at an end thereof remote from the end opening, in an inwardly directed portion, the cap including a part which engages said inwardly directed portion, when said cap closes the outlet passage, before said inwardly directed portion outwardly.

26. A container according to claim 25 wherein the outlet passage includes a second inwardly directed portion adjacent said first-mentioned inwardly directed portion, said cap surface engaging both portions when the cap closes the outlet passage.

27. A container according to any one of claims 24 to 26 wherein said cap surface is a frusto-conical surface.

28. A container according to any one of claims 1 to 27 wherein the outlet passage includes an outlet opening, said outlet opening carrying an annular axially projecting sealing lip, the cap including a surface which, when the cap closes the outlet passage, engages said annular lip to form a seal.

29. A container according to any one of claims 1 to 28 wherein the cap carries an openable enclosure.

30. A container according to any preceding claim in which the outlet passage is formed from a material flexible such that the application of the force causes the material to flex.

31. A container according to claim 30 in which the material is PVC.

32. A container according to any one of claims 1 to 31 and in which the cap, when closing the outlet passage, applies a force to the interior surface of the outlet passage, a retaining ring being provided around the exterior of the outlet passage to limit the effect of the force on the outlet passage.

33. A container substantially as hereinbefore described with reference to Figure 1 or Figure 2 or Figure 3 or Figure 4 or Figure 5 or Figure 6 or Figure 7 or Figure 9 of the accompanying drawings.