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(11) | EP 0 228 867 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Plastics cup |
| (57) A thin walled disposable plastics cup comprises a base (1) and a side wall (2). The
side wall includes a first upwardly facing inwardly and upwardly tapering external
conical surface (8) adjacent the base, a second downwardly facing correspondingly
inwardly and upwardly tapering internal conical surface (11) located above the first
surface (8). and surfaces which cooperate resiliently to urge the first conical surface
(8) of the upper cup into sealing engagement with the second conical surface (11)
of the lower cup, and so provide an isolated sealed space between the cups for holding
ingredients to produce a beverage. An upper part of the side wall also includes a
downwardly facing externally projecting shoulder (5) and, above this, an upwardly
facing internally projecting shoulder (6). When the cups are subjected to an end loading
sufficient to deform the resilient means (7, 10) and allow the upper cup to move downwards
with respect to the lower cup, the upwardly and downwardly facing shoulders (5, 6)
move into engagement to prevent furthertelescop- ing of the cups. |
[0001] This invention relates to plastics cups which are intended to be used once only and, particularly to such cups known as ingredient cups. A stack of such cups includes the ingredients to form a beverage loaded into spaces between adjacent cups of the stack so that, in the preparation of a beverage, the lowermost cup is simply released from the stack and filled with water to produce a cup of beverage.
[0002] Many attempts have been made in the past to provide an ingredient cup which firstly, provides a good airtight seal between adjacent cups of the stack so preventing the beverage ingredients from deteriorating as a result of the entry of water vapour and secondly to provide a stack which, whilst spaces between the cups are effectively sealed, does not get damaged during transit, for example when a case containing stacks of such cups is dropped. Frequently, in the past, cups in such a stack have tended to telescope together as the result of vibrational end loadings on the stack that occur during transport. When the cups are telescoped together they can split which, not only destroys that cup but also allows the beverage ingredients from that cup to contaminate the remainder of the stack. Further, even if the cups do not split once they have been telescoped together they often jam and, thereafter, are difficult to separate. This can lead to malfunctioning and damage of a vending machine in which the stack of cups are subsequently used.
[0003] One early attempt that we have made to overcome this problem is disclosed in GB-A-1524304. This specification discloses a thin-walled plastics cup in which an upwardly facing frustoconical surface adjacent the base of one cup is arranged to form a seal with a downwardly facing frustoconical surface located above the base of a lowermost cup. The two frustoconical surfaces are urged together to maintain the seal by cooperating formations immediately beneath both frustoconical sealing surfaces. These cooperating formation also adsorb axial loadings supplied to the stack of cups and this helps to reduce the telescoping. However, when subjected to high vibrational load these coorporating formations can be permanently damaged and so no longer urge the cooperating frustoconical sealing surfaces together. This results in no effective seal being formed between adjacent cups with the consequent deterioration in the ingredients.
[0004] Another proposal made by the inventor of the present invention is disclosed in GB-A-2044076 which also discloses a thin walled plastics cup having a pair of frusto-conical surfaces which cooperate to provide a seal in the same way as in GB-A-1524304. However, instead of cooperating formations located immediately beneath the frustoconical sealing surfaces this example of a cup includes opposed shoulders located towards the top of the cup which abut when one cup is nested inside another. The tension in the side walls between the upper shoulders and the lower frustoconical sealing surfaces holds the two lower frustoconical sealing surfaces into sealing engagement. There is very little resilience in a stack of such cups since the abutting shoulders are permanently in contact with one another and again any severe axial shock tends to cause these abutting surfaces to override resulting in the seal between the two opposed frustoconical surfaces being broken.
[0005] According to this invention a thin walled disposable plastics cup comprises a base, and a side wall comprising a first upwardly facing inwardly and upwardly tapering external conical surface adjacent the base, a second downwardly facing correspondingly inwardly and upwardly tapering internal conical surface located above the first surface, and cooperating means at least one of which is resilient, which are located beneath the second conical surface and which when two cups are nested together cooperate resiliently to urge the first conical surface of the upper cup into sealing engagement with the second conical surface of the lower cup and so provide an isolated sealed space between the cups for holding ingredients to produce a beverage, an upper part of the side wall also including a downwardly facing externally projecting shoulder and, above this, an upwardly facing internally projecting shoulder, the distance between the first conical surface and the downwardly facing shoulder being greater than that between the second conical surface and the upwardly facing shoulder so that, when two cups are nested together with their first and second conical surfaces held in sealing engagement, the upwardly and downwardly facing shoulders are out of engagement but when the cups are subjected to an end loading sufficient to deform the resilient means and allow the upper cup to move downwards with respect to the lower cup, the upwardly and downwardly facing shoulders move into engagement to prevent further telescoping of the cups.
[0006] Preferably the resilient means comprise a third inwardly and downwardly tapering conical surface, and a projecting shoulder located beneath the second conical surface which in adjacent cups of a stack engage with one another below the co-operating first and second sealing surfaces. The projecting shoulder engages the conical surface and the inherent resilience of one or both of them provides compressive spring forces which urge together the first and second conical surfaces to form an effective sealing engagement between them. Not only this but these compressive spring forces also tend to absorb moderate transient end loads applied to a stack of such cups and this acts to prevent telescoping of adjacent cups in the stack. If a large axial load is applied to the stack the internally and externally projecting shoulders in the upper part of the side walls engage to prevent telescoping and protect the resilient means from excessive loading and consequent damage. Thus, as soon as the end load is removed the seal is restored and the quality of the seal is maintained even after the stack of cups is subjected to a large, transient axial shock.
[0007] A further earlier example of plastic cup that we have proposed is disclosed in GB-A-1599396. This type of plastic cup does bear a superficial resemblance to the present invention but neither operates in the same fashion nor is as effective. This specification describes a thick-walled cup made of a foamed plastics material which has structural properties and compressive behaviour which is markedly different from that of the thin walled plastic cups which are the subject of the present invention. The cup includes an outwardly projecting annular rib formed around the base of each cup and a corresponding groove formed around the inside of the cup above its base so that, in use, the outwardly projecting rib formed around the outside of an uppermost cup is received by the groove of a lower cup. The wall thickness of the side wall of the cup immediately below the groove is increased from that immediately above the groove to provide a step which resists any tendency for the cups of the stack to telescope when subjected to an axial load. To ensure that the outwardly projecting rib is seated correctly in the groove two cylindrical surfaces of substantially the same diameter are provided, one on the inside towards the upper part of the cup and one, on the outside below this. These two cylindrical surfaces cooperate to prevent any tilting of the cups of the stack relative to one another and, whilst both of these cylindrical surfaces terminate in a shoulder these shoulders are held permanently out of contact with one another and play no part in preventing axial compression of the stack of cups.
[0008] Preferably the internally projecting shoulder or the downwardly tapering conical surface is circumferentially discontinuous. This provides greater circumferential flexibility to the cup so enabling it to be demoulded more easily during its manufacture. Preferably one of the upwardly and downwardly facing shoulders are also formed so that they are circumferentially discontinuous. Again this facilitates demoulding of the cup during production.
[0009] The projecting shoulder may be formed as an external shoulder at the join between the base and the side wall and, in this case, the downwardly tapering conical surface is an internal surface located between the first and second sealing surfaces. Preferably, however the projecting shoulder is formed as an internally projecting shoulder located between the first and second sealing surfaces. In this case the downwardly tapering conical surface is a downwardly facing external surface located between the base and the first sealing surface.
[0010] Preferably the side wall of the cup is corrugated in the axial direction which both stiffens radially the side wall and also provides means to enable the cup to be gripped more easily by the fingers of the user, particularly when the cup is filled with hot beverage.
[0011] Preferably the cup is made by a conventional thermo- forming process and the material distribution is arranged so that the upper part of the cup which includes both the upwardly and downwardly facing shoulders as well as the circumferentially extending corrugation to provide the finger gripping means has a greater wall thickness than the lower portion of the cup including the first and second conical sealing surfaces and the resilient means. This provides a cup which feels more solid to the user and which has the greatest wall thickness and hence strength around its anti-telescoping features, the upwardly and downwardly facing shoulders, whilst, at the same time enables less material to be used in the lower part of the cup. Firstly this saves on material and secondly, by using thinner material provides the inherent resilience required to produce the compressive spring forces. This also helps produce much wider production tolerances since, in production it is much easier to produce cups having a thicker upper sidewall and a thinner lower side wall and base than to achieve, for example, a uniform material distribution or a thicker base.
[0012] A particular example of various cups in accordance with this invention will now be described with reference to the accompanying drawings:-
Figure 1 is a side elevation of a first example of the cup;
Figure 2 is a side elevation of a second example of the cup;
Figure 3 is a side elevation of a third example of cup;
Figure 4 is a side elevation of a fifth example of cup with one version, version A, shown at the left hand side of the cup and a modified version, version B, on the right hand side of the cup;
Figures 5, 6 and 7 are radial sections through a pair of the first example of cups showing different degrees of nesting;
Figure 8 is a radial section through parts of the first example of cup;
Figure 9 is a side elevation of the bottom corner of sixth example of cup;
Figure 10 is a scrap radial section through a pair of nested sixth examples of cup; and,
Figure 11 is a side elevation of a modification of the sixth example.
[0013] The first example of cup comprises a base 1 and side wall 2 with a rolled top rim 3. The side wall 2 includes three circumferentially extending corrugations 4 to provide a finger gripping portion. A continuous downwardly facing external shoulder 5 is located towards the top of the side wall 2 and an internally projecting upwardly facing shoulder 6 which is discontinuous in the circumferential direction is located above the shoulder 5.
[0014] At the bottom of the side wall 2 is located a generally downwardly facing frustoconical surface 7 making an included angle of approximately 135° with the base 1 of the cup. Above this is a generally upwardly facing frustoconical surface 8 which subtends an angle of approximately 45° with the base 1. This is followed by a generally upstanding portion of side wall 9. An internally projecting upwardly facing shoulder 10 which, in this example, is circumferentially discontinuous is located above the portion 9. A generally downwardly facing frustoconical surface 11 which is inclined at a corresponding angle to the surface 8 is located above the shoulder 10. A generally upwardly facing internal conical shoulder 12 is located above the shoulder 11 and the junction between the surfaces 11 and 12 includes a number of circumferentially extending corrugations 13.
[0015] After manufacture the cups are loosely stacked together and are held in the configuration shown in Figure 5 with the external conical surface 7 resting on the internal conical surface 12. In this condition the cups are not locked together. Cups are then individually separated from the stack and filled with ingredients to form a beverage. After this, the cups are again nested together only, this time, after initially adopting the configuration shown in Figure 5 the cups are then subjected to a further end loading which causes the side wall 2 to bow and the surfaces 7 and 12 to ride over one another. The side wall then springs back to, as far as possible, its undeformed position and the adjacent cups take up the configuration shown in Figure 6 with the conical surfaces 8 and 11 forming a continuous annular seal which isolates the internal base portion of each cup from the atmosphere. In the position shown in Figure 6 the shoulder 10 is in tight engagement with the conical surface 7 and, both are deformed to some extent to form a positive upwards sealing force driving the surfaces 8 and 11 into sealing engagement. In this position the shoulders 5 and 6 are separated from one another, typically by a distance such as 2 mm and again this is shown in Figure 6.
[0016] Figure 7 shows the arrangement between the cups when they are subjected to an end loading, for example as a result of a stack of such cups being dropped or suffering vibrational loads during transport. When the top cup is moved downwards with respect to the lower cup the shoulder 10 and conical surface 7 deforms further so absorbing some of the end loading applied to the cup and then the shoulders 5 and 6 engage one another as shown in Figure 7. The shoulders 5 and 6 prevent further telescoping of the cup. When the end loading is removed the resilience of the shoulders 10 and surface 7 once again urge the conical sealing surfaces 8 and 11 into contact to restore the seal.
[0017] The discontinuous nature of the shoulder 10 and the shoulder 6 as shown in this first example enable the side wall 2 of the cup to deform more easily to enable the cup to be demoulded from a thermoforming mould. The corrugation 13 provides air passages to enable the air trapped between adjacent cups to escape as the conical surfaces 7 and 12 move over one another over to place the cups into the locked condition shown in Figure 6. Typically the cups are thermoformed from high impact polystyrene sheet material having an initial thickness of 0.6 mm. Such cups can be manufactured using the Hannifin or Illig processes and typically the final wall thickness of the resulting cup is around 0.25 mm in the upper part of the side wall of the cup around the finger gripping portions 4 and the shoulders 5 and 6 and 0.20 mm in the base 1 and the lower portion of the side wall 2 around the surfaces 7, 8, 9, 10, 11 and 12.
[0018] Another version of the cup is shown in Figure 2 in which similar reference numerals have been used. The sole differences between this example and that shown in Figure 1 are that, in this example, the conical surface 7 has an interrupted nature and includes recesses 14, and that the shoulder 10 is continuous. As can be seen the cooperation between the surface 7 and the shoulder 10 is substantially the same as in the first example when these are engaged when adjacent cups are locked together in a stack.
[0019] A further version of the cup is shown in Figure 3 and again similar reference numerals are used. In this example the elements of the discontinuous shoulder 6 have a smaller circumferential extent and are greater in number than those shown in Figure 1.
[0020] Figure 4 shows two different versions of the shoulder 6. In the version shown on the A side of Figure 4 the shoulders are formed by the top portions of semi-circular depressions of the side wall 15 whilst, in the B side of the Figure the shoulder 6 are formed by the flat side of semi-circular depressions 16.
[0021] Figure 9 shows a further different arrangement in which the shoulder 10 is formed externally at the join between the base 1 and the side wall 2. The downwardly and inwardly directed frustoconical surface 7 is an internal surface extending between the sealing surfaces 8 and 11. The shoulder 10 and the frustoconical surface 7 co-operate in a similar way to the previous examples to provide a resilient upwards force to urge together the co-operating sealing surfaces 8 and 11.
1. A thin walled disposable plastics cup comprising a base (1) and a side wall (2),
comprising a first upwardly facing inwardly and upwardly tapering external conical
surface (8) adjacent the base, a second downwardly facing correspondingly inwardly
and upwardly tapering internal conical surface (11) located above the first surface
(8), and cooperating means (7, 10) at least one of which is resilient, which are located
beneath the second conical surface (11) and which when two cups are nested together
cooperate resiliently to urge the first conical surface (8) of the upper cup into
sealing engagement with the second conical surface (11) of the lower cup, and so provide
an isolated sealed space between the cups for holding ingredients to produce a beverage,
an upper part of the side wall also including a downwardly facing externally projecting
shoulder (5) and, above this, an upwardly facing internally projecting shoulder (6),
the distance between the first conical surface (8) and the downwardly facing shoulder
(5) being greater than that between the second conical surface (11) and the upwardly
facing shoulder (6) so that, when two cups are nested together with their first and
second conical surfaces (8, 11) held in sealing engagement, the upwardly and downwardly
facing shoulders (5, 6) are out of engagement but when the cups are subjected to an
end loading sufficient to deform the resilient means (7, 10) and allow the upper cup
to move downwards with respect to the lower cup, the upwardly and downwardly facing
shoulders (5, 6) move into engagement to prevent further telescoping of the cups.
2. A cup according to claim 1 in which the resilient means comprise a third inwardly
and downwardly tapering conical surface (7), and a projecting shoulder (10) located
beneath the second conical surface (11) which in adjacent cups of a stack engage with
one another below the co-operating first and second sealing surfaces.
3. A cup according to claim 2 in which one of the internally projecting shoulder (10)
and the third downwardly tapering conical surface (7) is circumferentially discontinuous.
4. A cup according to claim 2 or 3, in which the projecting shoulder (10) is formed
as an internally projecting shoulder located between the first and second sealing
surfaces and the downwardly tapering conical surface (7) is a downwardly facing external
surface located between the base and the first sealing surface (8).
5. A cup according to any one of the preceding claims in which one of the upwardly
and downwardly facing shoulders (5, 6) is formed. so that it is circumferentially
discontinuous.
6. A cup according to any one of the preceding claims in which the side wall (2) of
the cup is corrugated in the axial direction.
7. A cup according to any one of the preceding claims formed by a conventional thermo-forming
process and further characterised in that the material distribution is arranged so
that the upper part of the side wall (2) has a greater wall thickness than the lower
part of the side wall (2).