Capsules

Abstract

The present invention provides a method of assembling a filter element (8) with a cup-shaped capsule body (2) using a combined weld-head (70) and former (80), comprising the steps of positioning the filter element (8) at or near a mouth of the cup-shaped capsule body (2), moving the combined weld-head (70) and former (80) so as to contact and drive the filter element (8) into the cup-shaped capsule body (2), wherein, the filter element (8) is deformed by a sprung-loaded former (80) of the combined weld-head (70) and former (80) to form a cup-shaped filter element (56), and using a weld-head (70) of the combined weld-head (70) and former (80) to bond the cup-shaped filter element (56) to the cup-shaped capsule body (2). The present invention further provides a method of making a beverage capsule and a beverage capsule produced using this method.

Claims

1. A method of assembling a filter element with a cup-shaped capsule body using a combined weld-head and former, comprising the steps of: a) positioning the filter element at or near a mouth of the cup-shaped capsule body; b) moving the combined weld-head and former so as to contact and drive the filter element into the cup-shaped capsule body; c) wherein, during step b), the filter element is deformed by a spring-loaded former of the combined weld-head and former to form a cup-shaped filter element; and d) using a weld-head of the combined weld-head and former to bond the cup-shaped filter element to the cup-shaped capsule body; wherein the spring-loaded former can move toward the weld-head against a spring bias; and wherein a distance between the weld-head and a bottom of the spring-loaded former can vary during step d) by allowing the spring-loaded former to move toward the weld-head against the spring bias to limit movement of the former into the cup-shaped capsule body; wherein the spring-loaded former comprises a cup-shaped forming body, wherein a cup-shaped portion of the forming body is wholly formed from a flexible material, and wherein the forming body comprises a base and an upwardly extending side wall.

2. A method as claimed in claim 1, wherein a magnitude of a peak force applied to the filter element by the spring-loaded former is limited by allowing the spring-loaded former to move relative to the weld-head against a spring bias.

3. A method as claimed in claim 2, wherein the magnitude of the peak force applied to the filter element is less than the force required to tear the cup-shaped filter element.

4. A method as claimed in claim 2, wherein the magnitude of the peak force applied to the filter element is less than 45N.

5. A method as claimed in claim 2, wherein the magnitude of the peak force applied to the filter element is less than 40N.

6. A method as claimed in claim 2, wherein the magnitude of the peak force applied to the filter element is less than 30N.

7. A method as claimed in claim 1 wherein, at the end of step b), a portion of the cup-shaped filter element is held in contact with the cup-shaped capsule body by the weld-head.

8. A method as claimed in claim 1 wherein the cup-shaped filter element is bonded to the cup-shaped capsule body such that the cup-shaped filter element is suspended within the cup-shaped capsule body, with a base of the cup-shaped filter element being out of contact with a base of the cup-shaped capsule body.

9. A method as claimed in claim 1, wherein, during step d), a portion of the cup-shaped filter element is bonded to the cup-shaped capsule body by using a heated portion of the weld-head.

10. A method as claimed in claim 9, wherein, during step d), at least a portion of the cup-shaped capsule body is softened by the heated portion of the weld-head, thereby allowing the weld-head to move further into the cup-shaped capsule body.

11. A method as claimed in claim 10, wherein during said further movement of the weld-head into the cup-shaped capsule body, further movement of the spring-loaded former into the cup-shaped capsule body is limited or avoided by allowing the spring-loaded former to move relative to the weld-head against the spring bias.

12. A method as claimed in claim 1, wherein the spring-loaded former is slidably coupled to the weld-head, with a compression spring extending between the spring-loaded former and the weld-head.

13. A method as claimed in claim 1, comprising the further step of: e) withdrawing the combined weld-head and former from the cup-shaped capsule body.

14. A method as claimed in claim 13, wherein during step e) the spring-loaded former flexes to aid decoupling of the spring-loaded former from the cup-shaped filter element.

15. A method of making a beverage capsule, comprising the steps of: i) filling a portion of one or more beverage ingredients into a cup-shaped capsule body having a filter element bonded thereto by the method of claim 1; and ii) closing and sealing the cup-shaped capsule body using a lid.

16. A method as claimed in claim 1, wherein step d) includes using the weld-head to bond the cup-shaped filter element to the interior of the cup-shaped capsule body.

17. A method as claimed in claim 1, wherein the side wall of the forming body has a generally frusto-conical shape.

18. A method as claimed in claim 1, wherein a compression spring extends between the spring-loaded former and the weld-head, and wherein the compression spring is arranged within the cup-shaped forming body.

19. A combined weld-head and former for use in assembling a beverage capsule, comprising a weld-head and a former, wherein the former is spring-loaded; wherein the spring-loaded former comprises a cup-shaped forming body, wherein a cup-shaped portion of the forming body is wholly formed from a flexible material, and wherein the forming body comprises a base and upwardly extending side wall.

20. A combined weld-head and former as claimed in claim 19, wherein the spring-loaded former is slidably coupled to the weld-head, with a spring extending between the spring-loaded former and the weld-head.

21. Use of a combined weld-head and former as claimed in claim 19 to assemble a filter element with a cup-shaped capsule body.

22. A combined weld-head and former as claimed in claim 19, wherein the side wall of the forming body has a generally frusto-conical shape.

23. A combined weld-head and former as claimed in claim 19, wherein a compression spring extends between the spring-loaded former and the weld-head, and wherein the compression spring is arranged within the cup-shaped forming body.

Description

DESCRIPTION OF THE DRAWINGS

(1) Aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 is a cross-sectional representation of a combined weld-head and former, a cup-shaped capsule body and a filter element before assembly;

(3) FIG. 2 is a cross-sectional representation of the filter element being inserted into the cup-shaped capsule body by the combined. weld-head and former;

(4) FIG. 3 is a cross-sectional representation of the filter element inserted into the cup-shaped capsule body and ready for bonding;

(5) FIG. 4 is a cross-sectional representation of the combined weld-head and former being withdrawn from the cupshaped capsule body; and

(6) FIG. 5 is a perspective representation of a capsule formed using the cup-shaped capsule body of FIG. 4.

DETAILED DESCRIPTION

(7) A capsule 1, which may be, for example, a beverage capsule containing a portion of one or more beverage ingredients, is shown in FIG. 5. The capsule 1 comprises a cup-shaped capsule body 2 having a base 4 of a circular shape and an upwardly extending side wall 5. An open upper end of the cup-shaped capsule body 2 is closed and sealed by a lid 3. The capsule 1 contains a cup-shaped filter element 56 (shown in FIG. 4) which serves to allow a liquid to pass there through while retaining a solid residue. The lid 3 provides an upper piercing surface of the capsule 1. The base 4 provides a lower piercing surface of the capsule 1.

(8) The cup-shaped. capsule body 2 may be formed from a laminate having layers of polystyrene, ethylene vinyl alcohol (EVOH) and polyethylene.

(9) The lid 3 may be formed from polyethylene, polypropylene, polyesters including polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, polyamides including nylon, polyurethane, paper, viscose and/or a metal foil. The lid may comprise a laminate, be metallised or formed of copolymers. In one example, the lid comprises a polyethylene-aluminium laminate.

(10) FIG. 1 shows the cup-shaped capsule body 2 and a filter element 8 from which the cup-shaped filter element 56 will be formed. The filter element 8 comprises a flexible, die-cut circular piece of suitable heat-sealable filter material.

(11) FIG. 1 also shows a combined weld-head and former 60 that is used to assemble the filter element 8 with the cupshaped capsule body 2.

(12) As shown in FIG. 1, the side wall 5 of the cup-shaped capsule body is provided on its inner face with a plurality of flutes 28 that project radially inwards so as to define channels 29 interposed between the flutes 28 which run down a substantial length of the side wall 5 from the open upper end 20 towards the base 4. The side wall 5 is generally frustoconical in shape with a diameter at the open upper end 20 being larger than a diameter at the side wall 5 adjacent to the base 4. An upper region of the side wall 5 adjacent to the upper rim 21 has an inwardly tapering section 22 extending downwardly from the upper rim 21. In addition, the side wall 5 in the region of the base 4 is provided with an outwardly tapering section 23. An upper end of the outwardly tapering section 23 connects to the remainder of the side wall 5 at an out-turned shoulder 24.

(13) The combined weld-head and former 60 comprises a weldhead 70 and a sprung-loaded former 80.

(14) The weld-head 70 comprises a generally solid body 71 having a bore 72 running there through. The bore 72 is located at a centre of the solid body 71 and orientated along a longitudinal axis of the weld-head 70. An upper end of the solid body 71 is provided with a plurality of threaded bores 75 to allow the weld-head 70 to be coupled to a mechanism (not shown) that controls movement and heating of the weld-head 70. A lower end face 73 of the weld-head 70 is perpendicular to the longitudinal axis. A welding zone 74 towards a lower end of the solid body 71 is shaped to conform with the cup-shaped capsule body 2. In the illustrated example the welding zone 74 comprises two tapered surfaces that conform in shape to inwardly tapering section 22 of the cup-shaped capsule body 2. The weld-head may be formed from a suitable material able to transmit heat energy via the welding zone 74. Examples include mild steel, aluminium, copper and brass.

(15) The sprung-loaded former 80 comprises a forming body 86, a coupling leg 83 and a spring 84. The forming body 86 comprises a base 82 of a circular shape and a side wall 81 which extends upwardly from the base 82 and terminates in a circular rim 87. The side wall 81 has a frusto-conical shape, the inclination of which generally conforms to the inclination of the side wall 5 of the cup-shaped capsule body 2. An outer corner 85 at the junction between the side wall 81 and the base 82 is radiused to prevent any sharp edges which might tear the filter element 8. The coupling leg 83 extends upwardly from the base 82 within the side wall 81. The coupling leg 83 is cylindrical and located at a centre of the forming body 86 and is shaped and sized to be received as a sliding fit within the bore 72 of the weld-head 70. The forming body 86 is made of a rigid material, such as aluminium or copper. Alternatively, a material with a degree of flexibility, such as a silicone rubber, could be utilised.

(16) The spring 84 is located about the coupling leg 83 and extends from an inner face of the base 82 to the lower end face 73 of the weld-head 70. The spring is a helical compression spring.

(17) The coupling leg 83 is retained within the bore 72 by means of a threaded bolt, bore and washer arrangement 88 at an upper end of the coupling leg 83.

(18) As assembled and viewed in the orientation shown in FIG. 1, the sprung-loaded former 80 at rest is biased downwards away from the weld-head 70 by the spring 84 such that a gap 90 exists between the circular rim 87 of the side wall of the forming body 86 and the lower end face 73 of the weld-head 70.

(19) The steps in assembling the filter element 8 with the cup-shaped capsule body 2 are shown in FIGS. 2 to 4.

(20) In a first step shown in FIG. 2, the cup-shaped capsule body 2 is supported in a suitable holder (not shown) and the combined weld-head and former 60 is moved downwards by mechanical means such that the filter element 8 is driven down into the open upper end 20 of the cup-shaped capsule body 2 by the sprung-loaded formed 80. This movement causes the previously flat filter element 8 to begin to be deformed into the cup-shaped filter element 56. A central portion of the filter element 8 contacted by the base 82 of the forming body 86 will become a base 52 of the cup-shaped filter element 56. An intermediate zone 53 of the filter element 8 will form a portion of a side wall 51 of the cup-shaped filter element 56. A peripheral zone 50 of the filter element 8 will form a bonded zone of the side wall 51 of the cup-shaped filter element 56. During this first stage the resistance to movement of the filter element 8 is low and consequently the sprung-loaded former 80 moves in unison with the weld-head 70 and the size of the gap 90 remains substantially unchanged.

(21) Insertion of the combined weld-head and former 60 continues until the point is reached, shown in FIG. 3, where the filter element 8 has been fully inserted and the weld-head 70 has been brought into contact with the peripheral zone 50 of the filter element 8. At this point the filter element 8 has been fully deformed into the cup-shaped filter element 56. Also, the welding zone 74 of the weld-head 70 acts to firmly hold the peripheral zone 50 of the filter element 8 against the inwardly tapering section 22 of the cup-shaped capsule body 2. As can be seen from FIG. 3, the base 52 of the cup-shaped filter element 56 is held free of the base 4 of the cup-shaped capsule 2 by a distance 55. Up to this point the resistance to movement of the filter element 8 remains low and consequently the sprung-loaded former 80 moves in unison with the weld-head 70 and the size of the gap 90 remains substantially unchanged.

(22) Bonding of the cup-shaped filter element 56 to the cup-shaped capsule body 2 now takes place due to heat energy from the welding zone 74 causing localised fusing of the material of the filter element 8 and the cup-shaped capsule body 2. The heating of the material of the cup-shaped capsule body 2 has been found to have a tendency to soften and/or thin the cup-shaped capsule body 2. This allows the weld-head 70 to move downwards, further into the cup-shaped capsule body 2. This further inward movement of the weld-head 70 would have a tendency, if the forming body 86 were not sprung-loaded, to impart an increased force to the cup-shaped filter element 56 (which is now not free to move relative to the cup-shaped capsule body 2). However, the sprung-loaded form of the former 80 means that the further inward movement of the weld-head 70 is accommodated by compliance of the combined weld-head and former 60—specifically it is accommodated by compression of the spring 84 so as to move the forming body 86 relative to the weld-head so as to reduce the size of the gap 90.

(23) The final stage, shown in FIG. 4, is to withdraw the combined weld-head and former 60. At this stage, withdrawal of the forming body 86 from the cup-shaped filter element 56 may be aided, the case where the forming body 86 is formed from a flexible material, by flexing of the forming body 86 which reduces the chances of tearing of the cup-shaped filter element 56.

(24) The assembly of the cup-shaped filter element 56 and the cup-shaped capsule body 2 may then undergo further process steps in order to fill the capsule with a portion of one or more beverage ingredients and to apply the lid 3.

(25) As part of the assembly method described above, the spring rate of the sprung-loaded former 80 should be chosen as required depending on the particular geometry of the cup-shaped capsule body 2 and the material of the filter element 8 to ensure that the peak load imparted to the filter element a/cup-shaped filter element 56 does not exceed its tearing strength. The spring rate of the sprung-loaded former 80 depends not only on the spring rate of the spring 84 itself but also the effects of friction between the components of the former 80. In one experiment, a circular piece of filter material comprising woven paper and polyethylene of diameter 0.97 mm and thickness 0.1 mm, was bonded according to the method described above in a cup-shaped capsule body 2 having an inner face formed from polyethylene and an internal diameter at the open upper mouth 20 of 45 mm. The depth of the cup-shaped filter element 56 so formed was 33 mm. For this example a spring rate of from 2.0 to 4.0 N/mm, preferably 3.0 N/mm for the sprung-loaded former 80 was found to be beneficial. This was achieved with use of a helical compression spring having a spring rate of from 1.0 to 3.0 N/mm, preferably 2.0 N/mm.

EXAMPLES

(26) Tests were conducted to ascertain the tearing strength of a typical filter element. The results are shown in Table 1 below. The filter element comprised a circular piece of filter material comprising woven paper and polyethylene of diameter 97 mm and thickness 0.1 mm. A forming body 86 was driven at a fixed rate of 100 mm/minute until tearing of the filter element occurred.

(27) TABLE-US-00001 TABLE 1 Peak force at point of tearing Test (N) Run 1 51.18 Run 2 49.72 Run 3 58.67 Run 4 58.46 Run 5 62.59 Run 6 53.05 Run 7 53.83 Run 8 48.05

(28) From this, it can be seen that, for this example, limiting the peak force applied to the filter element 8/cup-shaped filter element 56 to under 48N is preferred to reduce or eliminate the chances of tearing.

(29) Comparative tests were then undertaken to compare the peak force applied to the filter element 8/cup-shaped filter element 56 using the method of the present disclosure (making use of a sprung-loaded former 80) compared to an assembly method using a weld-head and former that consists of a solid bung former that is not sprung-loaded relative to the weld-head. As above, the filter material comprised woven paper and polyethylene of diameter 97 mm and thickness 0.1 mm. The capsule body 2 comprised an inner face formed from polyethylene and an internal diameter at the open upper mouth 20 of 45 mm. The depth of the cup-shaped filter element 56 formed was 33 mm. For the combined weld-head and former 60, a spring rate of 3.0 N/mm for the sprung-loaded former 80 was chosen by use of a compression spring having a spring rate of 2.0 N/mm. The results are shown in Table 2 below.

(30) TABLE-US-00002 TABLE 2 Peak force Test applied (N) Observations Solid bung former 50.30 Tearing observed Run 1 Solid bung former 54.83 No tearing Run 2 Solid bung former 52.58 Tearing observed Run 3 Sprung-loaded former 25.22 No tearing Run 1 Sprung-loaded former 27.62 No tearing Run 2 Sprung-loaded former 25.37 No tearing Run 3 Sprung-loaded former 27.00 No tearing Run 4 Sprung-loaded former 26.93 No tearing Run 5

(31) Use of the sprung-loaded formed resulted in a significantly reducing peak load being applied to the filter element a/cup-shaped filter element 56 and in every case prevented tearing of the material.

(32) In the above aspect, the forming body 86 comprises an intergral, cup-shaped, thin-walled structure. However, other forms of forming member may be used as part of the sprung-loaded former 80. For example, the forming body 86 may be formed from a plurality of separate parts. The forming body 86 may comprise a base 82 but no side wall.