NZ546858A - Filter holder for espresso machine - Google Patents

Abstract

An assembly comprising an espresso coffee machine (28) and a filter holder (10) wherein the machine and filter holder have respective coupling formations (36, 38) to enable the filter holder to be operatively coupled to the machine. The coupling formations provide a two position interlock arrangement, including a first position in which the filter holder is in sealed engagement with the machine so that in use the machine discharges fluid under pressure through the filter holder and a second position in which the filter holder is in non-sealed engagement with the machine so that in use fluid discharging under pressure from the machine is able to escape between the filter holder and the machine.

Description

si* Patents Form No. 5 Our RefS81040222 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Filter holder for espresso machine We, Sunbeam Corporation Limited, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: intellectual property office of n.z. - 2 MAY 2006 Freehills Patent & Trade Mark Attorneys Sydney\005060936 RECEIVE# 005060643 Filter holder for espresso machine Field of the invention This invention relates to an espresso coffee machine of the type which has a filter holder adapted to be detachably coupled to the espresso machine by way of a bayonet coupling or the 5 like.

Background of the invention A typical espresso coffee machine is designed to discharge steam and high temperature water under pressure through ground coffee which is contained in a filter holder. The filter holder typically includes a filter strainer in which the coffee is contained and the holder is 10 adapted to be detachably locked or coupled to the espresso machine by way of a bayonet coupling or the like.

Usually the filter holder is provided with a handle, and the filter holder is rotated relative to the espresso machine to couple or uncouple the holder from the machine, depending on the direction of the rotation. The filter holder and the espresso machine are provided with cam type 15 formations thereon which urge the holder against a sealing surface on the espresso machine to form a fluid tight seal between the espresso machine and the filter holder.

Typical espresso machines include a water pump adapted to provide water under a pressure of between about 10 and 15 bar, depending on the type of machine. The pump urges hot water and steam through the ground coffee located in the filter holder. It will thus be appreciated 20 that the coupling arrangement between the filter holder and espresso machine must be such that the filter holder is able to operate under the high operating pressure of the machine.

Typically the filter holder is removed from the machine after each cup of coffee has been brewed and the charge of ground coffee replaced each time a new cup of coffee is required. The coupling and uncoupling of the filter holder is thus done when the machine is unpressurised. 005060643 It does, however, occur that from time to time the filter holder becomes disengaged from the machine in situations where the machine is pressurised. The disengagement of the filter holder from the machine under pressurised conditions may occur because of the vibrations or forces applied to the filter holder as water under pressure is urged through the filter strainer. This 5 may occur where the filter holder is not properly coupled to the machine. Occasionally the machine and filter holder remain under a condition of elevated pressure, even though the coffee making cycle has completed. This may, for example, occur when the filter strainer becomes clogged, and the pressure is not able to dissipate through the filter holder.

When the filter holder disengages from the machine under conditions of elevated 10 pressure this can cause the filter holder to be forced away from the machine under pressure, often causing the filled or partially filled coffee cup to be broken and also potentially discharging high pressure steam, hot water, and coffee grind into the area immediately adjacent the machine.

This problem is particularly prevalent in steam pressure espresso machines where steam pressure may be maintained, even after the coffee making cycle has completed.

One prior art arrangement for preventing the inadvertent disengagement of the filter holder from the machine is disclosed in US patent 5,642,656. That patent discloses an arrangement in which a locking pin engages with and locks the filter holder in position during the coffee making cycle. The pin is moved into locking engagement with the filter holder when the machine is under pressure, but when the pressure dissipates the pin automatically retracts, 20 allowing the filter holder to be disengaged from the machine. This system, when operating properly, effectively locks the filter holder to the machine and can prevent the aforementioned inadvertent disengagement of the filter holder from the machine. However, the locking pin system is prone to malfunction, particularly over time, and also adds significantly to the cost of the machine.

Summary of the Invention According to a first aspect of the invention there is provided an espresso coffee machine and filter holder assembly wherein the machine and filter holder each have respective coupling formations to enable the filter holder to be operatively coupled to the machine, said coupling 005060643 formations providing at least a two position interlock arrangement, including a first position in which the filter holder is in sealed engagement with the machine so that in use the machine will discharge fluid under pressure through the filter holder, and a second position in which the filter holder is still coupled to the machine, but in which fluid under pressure discharging from the 5 machine is able to escape between the filter holder and the machine.

Preferably the filter holder comprises a cup shaped body having a handle mounted thereto, the filter holder being adapted to be coupled to the machine by rotating the cup shaped body relative to the machine, and the coupling formations define a bayonet type coupling arrangement. Preferably the coupling formations include at least one cam surface which, on 10 rotation of the holder, causes the holder to be drawn into sealing engagement with a sealing surface on the machine. The filter holder and the machine preferably each include a plurality of coupling formations which will respectively engage with each other as the holder and machine are brought into operative engagement with each other. The coupling formation or formations on the holder preferably project radially outwardly from the cup shaped body of the holder, and 15 engage in cooperatively shaped slots or grooves or tracks in an outlet port from the machine, the cup shaped body and/or a filter member in the cup shaped body having a sealing surface on or near the operatively upper edge thereof, adapted to seal with an annular sealing surface located within the outlet port from the machine.

The configuration of the coupling formations on the holder and/or the machine are 20 preferably such that the holder is captively held in said second position in a detent arrangement which requires manipulation of the filter holder by applying a lateral force to the handle in order to overcome the detent arrangement to thereby disengage the filter holder from the machine.

According to a second aspect of the invention there is provided a filter holder adapted to be coupled to an espresso coffee machine, the filter holder having at least one coupling 25 formation thereon adapted to interlock with a corresponding coupling formation on the machine, the coupling formation on the holder having first and second engagement surfaces each of which is adapted to engage with the coupling formation on the machine, the engagement surfaces being positioned and arranged such that if the first surface is engaged with the coupling formation on the machine the filter holder is in sealed engagement with the machine, and fluid under pressure 30 discharging from the machine discharges through the filter holder, and if the second engagement 005060643 surface is engaged with the coupling formation on the machine, fluid under pressure discharging from the machine is able to escape between the filter holder and the machine.

The filter holder preferably comprises a cup shaped body having a handle mounted thereto and the coupling formation comprises a radially outwardly directed lug or flange, said lug 5 or flange having said first and second engagement surfaces thereon. The filter holder is preferably adapted to be coupled to the machine in a bayonet type coupling arrangement in which the filter body is rotated as it is brought into engagement with the machine, and a cam surface is formed on said lug or flange intermediate said first and second surfaces, so that, on rotation of the holder relative to the machine the cam surface causes the holder to be drawn into 10 sealing engagement with the machine.

The second surface is preferably a concave shaped surface, thereby defining a detent arrangement requiring an application of lateral force to the handle in order to overcome the detent arrangement so as to enable the filter holder to be disengaged from the machine.

According to a third aspect of the invention there is provided an espresso coffee machine 15 adapted to be coupled to a filter holder, the machine comprising at least one coupling formation adapted to interlock with a corresponding coupling formation on the filter holder, the at least one coupling formation on the machine comprising first and second engagement surfaces each adapted to engage with the coupling formation on the filter holder, the engagement surfaces being positioned and arranged such that if the first engagement surface is engaged with the 20 coupling formation on the filter holder, the filter holder is in sealed engagement with the machine and fluid under pressure discharging from the machine discharges through the filter holder, and if the second engagement surface is engaged with the coupling formation ort the filter holder, the filter holder is in non-sealed engagement with the machine and fluid under pressure discharging from the machine is able to escape between the filter holder and the machine.

These and further features of the invention will be made apparent from the description of the embodiments thereof given below by way of examples. In the description reference is made to the accompanying drawings, but the specific features shown in the drawings should not be construed as limiting on the invention. 005060643 Brief description of the drawings Figure 1 shows a diagrammatic perspective view of a filter holder and the coupling formations on a coffee machine, Figure 2 shows a side view of the holder and coupling formations in an uncoupled 5 configuration; Figure 3 shows a side view similar to that of Figure 2, with the holder inserted into the machine, but uncoupled; Figure 4 shows a side view of the filter holder coupled to the machine; Figure 5 shows a side view of the filter holder partially uncoupled from the machine; and Figure 6 shows a coupling track of an espresso machine which is an alternative embodiment of the invention.

Detailed description of the embodiments Referring initially to figures 1 to 5, a filter holder 10 for an espresso coffee machine comprises a cup shaped body 12 having a handle 14 connected to the body. The body has a base 15 16 with an opening 18 therein through which coffee produced by the machine will pass in use. The coffee typically is then directed via two spouts or guides 19 into coffee cups located below the machine. The body 12 is basically cup shaped and defines an internal cavity 20 in which a removable filter strainer 22 is located. The strainer 22 has an outwardly directed inverted u-shaped flange 24 on the upper edge thereof which seats on the upper edge 26 of the body 12, 20 thereby supporting the strainer 22 above the base 16 of the body 12. The filter strainer 22 has a mesh or perforated construction, to allow coffee to pass through the strainer into the holder.

In use, the ground coffee will be located within the filter strainer 22 and the filter holder 10 will be coupled to an espresso coffee machine 28 in the manner described in more detail below. 005060643 The espresso coffee machine 28 includes passages (not shown) for supplying high temperature water and steam to ground coffee located in the strainer 22, thereby producing the espresso coffee in known manner. The outlet region from the machine defines an outlet port into which the filter holder 10 is connects in order to couple the filter holder 10 to the coffee machine 5 28. The filter holder is inserted into the machine in the direction of arrow 30, and is then rotated, in the direction of arrow 32 to couple the filter holder to the machine. These aspects are discussed in more detail below.

The filter holder 10 includes three radially outwardly directed coupling flanges 36 adapted to couple with corresponding coupling formations 38 on a machine 28. Other 10 configurations might have a different number of coupling formations, say two or four formations, for example. The coupling formations 38 and the outwardly directed flanges 36 thus form a bayonet type coupling arrangement. The configuration of each flange 36 and coupling formation 38 are such that either the flange or the coupling formation, or both, slope at a selected angle such that as the filter holder is rotated into position the slope or cam causes the filter holder 15 to be brought into sealing engagement with the machine. The slope angle is selected such that the coupling action is relatively quick and the force holding the filter holder to the machine is relatively high.

In use, the upper part of the filter holder 10 is inserted into the outlet port of the machine 28 and the holder 10 is then rotated through an angle of approximately 45° to 90° to cause the 20 coupling flanges 36 to properly engage the coupling formations 38 on the machine and the urge the filter holder 10 into sealing engagement with the machine 28. The machine 28 is provided with an elastomeric annular seal 40 against which the upper edge 26 of the filter holder 10 will engage to seal with the filter holder 10. Thus, when the filter holder 10 is properly engaged, as shown in Figure 4, with the machine 28 a fluid tight seal will be formed between the upper 25 region of the filter holder 10 and the annular seal 40, thereby ensuring that all high temperature water and steam being generated under pressure will pass through the filter strainer 22 into the chamber 20 and out of the outlet 18, thereby producing a high quality coffee beverage in known fashion.

It will be appreciated that the sealing arrangement between the seal 40 and the upper 30 edge 26 of the filter holder 10 should be fluid tight to ensure high pressure water and steam do not escape between the upper edge of the filter holder 10 and the machine. The seal 40 on the 005060643 8 machine is typically made from a heat resistant, relatively stiff material, such as silicone rubber. The top surface or the inner surface of the filter, near the top, will engage with the seal on the machine.

The filter holder in this embodiment includes three outwardly directed flanges 36 5 adapted to engage with corresponding coupling formations 38 in the espresso machine. The flanges 36 have a pair of engagement surfaces 42 and 44 on the operative side edge thereof. When the filter holder is engaged with the espresso machine, the coupling formation 38 of the machine will be engaged by those surfaces 42 and 44 during the interlocking process. It will be noted that the surface 42 is a further distance away from the upper edge 26 of the filter holder 10 than the surface 44. When the surface 42 is engaged with the coupling formation 38 of the machine the filter holder will be urged higher up into the machine, thus causing the upper edge 26 to engage with the seal 40 located in the machine. In other words, when the surface 42 is engaged with the coupling formation 38 the filter holder will be in its properly engaged position and the interface between the filter holder and the machine will be properly sealed. In this 15 position the machine will be ready to produce a cup of coffee in known manner. Figure 4 shows the filter holder fully coupled and sealed with the machine.

By rotating the filter holder in the opposite direction through an angle of between approximately 10° and 20° to the partially uncoupled position shown in Figure 5, the surface 44 on the flange 36 will be brought into engagement with the coupling formation 38 on the 20 machine. It will be appreciated that the surface 44 is closer to the upper edge 26 of the filter holder, so that when the surface 44 is engaged with the coupling formation 38 the surface 26 will be spaced away from the seal 40 on the machine but the filter holder will still be held in engagement with the machine. Complete disengagement of the filter holder from the machine will not take place until the filter holder is rotated further, that is, until the filter holder is rotated 25 so that the leading edge 48 of the flange 36 moves past the coupling formation 38, to the Figure 3 position.

It will be appreciated that when the coupling formation 38 is in engagement with the surface 44, the seal between the upper edge 26 of the filter holder and the seal 40 will be broken, and thus any pressurised fluid in the filter holder or the outlet port will dissipate between the 30 machine and the upper edge 26 of the filter holder without pushing or blowing the filter holder away from the coffee machine in the manner described above. In other words, high pressure fluid 005060643 9 will be able to escape while the filter holder 10 is still captively, although loosely, held by the machine.

It will also be appreciated that even where in situations where the filter holder inadvertently rotates relative to the espresso machine during the coffee making cycle when 5 significant pressures have developed within the machine, that pressurised fluid will be able to escape between the machine and the upper edge 26 of the filter holder without explosively forcing the filter holder away from the machine. Thus, the person charged with operating the espresso machine will immediately be aware of the partial disengagement of the filter holder from the machine, because of the escape of high pressure fluid from the machine, but the damage 10 caused by that escape of high pressure fluid will to a large extent be contained within the machine since the filter holder will remain captively held to the machine.

To ensure that the filter holder does not move of its own volition to completely disengage from the machine, the flange 36 may be provided with a detent arrangement indicated at numeral 50, requiring a lateral force to be provided on the handle 14 to properly disengage the 15 filter holder from the machine. Indeed, it is envisaged that the surface 44 will preferably have a concave shape as indicated at 50 to ensure that a lateral force is required to enable complete disengagement of the filter holder.

Clearly, different arrangements from that shown in figures 3 and 4 are possible, which will allow the filter holder to be properly sealed to the espresso machine in one position, and yet, 20 in a second position, be disengaged from that sealed condition, yet still captively held to the machine.

One such alternative arrangement is shown diagrammatically in Figure 6 of the drawings. In this embodiment the filter holder itself does not have a two position engagement surface but the espresso machine has a track which provides a bayonet type coupling which 25 serves the same two position function. As shown in Figure 6 the machine 52 has a series of grooves 54 formed at angularly spaced positions in a wall thereof. Outwardly directed lugs 58 secured to the filter holder engage in the grooves 54 in order to lock the filter holder to the machine. The grooves 54 each define a track 56 thereon against which the lug 58 on the filter holder travels into coupling engagement with the machine. As shown, the track 56 includes a 30 first position 60 which when engaged by the lug 58 will cause the filter holder to be sealed to the sealing surface on the machine, and a second position 62 which will define an arrangement in 005060643 which the filter holder is still captively held to the machine, but the seal between the machine and the filter holder is broken. As shown, the track 56 also defines a detent 64 over which the lug 58 will need to travel to exit from the groove 54.

Other coupling arrangements are possible which provide this two stage coupling 5 arrangement. For example, an arrangement in which a track is defined on the outer surface of the filter holder, that track being engageable by a pin or the like fixed to the machine and which locates in that track. Clearly, coupling arrangements other than bayonet type coupling arrangements are also possible although it will be appreciated that bayonet type coupling arrangements between a filter housing and a espresso coffee machine are relatively well known 10 and used in many such applications.

It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

It will also be understood that the term "comprises" (or its grammatical variants) as used in this specification is equivalent to the term "includes" and should not be taken as excluding the presence of other elements or features. 005342355 11

Claims (21)

Claims

1. An assembly comprising an espresso coffee machine and a filter holder wherein the machine and filter holder have respective coupling formations to enable the filter holder to be operatively coupled to the machine, said coupling formations providing at least a two position 5 interlock arrangement, including a first position in which the filter holder is in sealed engagement with the machine so that in use the machine discharges fluid under pressure through the filter holder and a second position in which the filter holder is in non-sealed engagement with the machine so that in use fluid discharging under pressure from the machine is able to escape between the filter holder and the machine. 10

2. An assembly according to claim 1 wherein the filter holder comprises a cup shaped body, the filter holder being adapted to be coupled to the machine by rotating the cup shaped body relative to the machine.

3. An assembly according to claim 2 wherein the coupling formations comprise at least one cam surface which, on rotation of the holder relative to the machine, causes the holder to be 15 drawn into sealing engagement with a sealing surface on the machine.

4. An assembly according to claim 3 wherein the filter holder and the machine each comprise a plurality of coupling formations that respectively engage with each other as the holder and machine are brought into operative engagement with each other.

5. An assembly according to claim 3 or 4 wherein the coupling formations on the filter 20 holder project radially outward from the cup shaped body of the holder and in use engage with cooperatively shaped tracks in an outlet port of the machine.

6. An assembly according to claim 5 wherein the sealing surface on the machine comprises an elastomeric annular seal in the outlet port and, in use, a sealing surface on or near an operatively upper edge of the cup shaped body is pressed against the annular seal to provide the 25 sealing engagement. intellectual property office of n.z. 3 0 OCT 2007 R ECEIVED 005342355v2.doc 005342355 12

7. An assembly according to claim 5 wherein the sealing surface on the machine comprises an elastomeric annular seal in the outlet port and, in use, a sealing surface on or near an operatively upper edge of a filter member positioned in the cup shaped body is pressed against the annular seal to provide the sealing engagement. 5

8. An assembly according to any one of claims 2 to 7wherein the cup shaped body of the filter holder has a handle mounted thereon, and wherein the holder is captively held in the second position in a detent arrangement which requires application of a lateral force to the handle to overcome the detent arrangement and thereby disengage the filter holder from the machine.

9. A filter holder adapted to be coupled to an espresso coffee machine, the filter holder 10 comprising at least one coupling formation adapted to interlock with a corresponding coupling formation on the machine, the at least one coupling formation on the holder comprising first and second engagement surfaces each adapted to engage with the coupling formation on the machine, the engagement surfaces being positioned and arranged such that if the first engagement surface is engaged with the coupling formation on the machine the 15 filter holder is in sealed engagement with the machine and fluid under pressure discharging from the machine discharges through the filter holder, and if the second engagement surface is engaged with the coupling formation on the machine i the filter holder is in non-sealed engagement with the machine and fluid under pressure discharging from the machine is able to escape between the filter holder and the machine. 20

10. A filter holder according to claim 9 wherein the filter holder comprises a cup shaped body and the at least one coupling formation comprises a radially outwardly directed flange on the cup shaped body, the flange having the first and second engagement surfaces thereon.

11. A filter holder according to claim 9 or claim 10 wherein the filter holder is adapted to be coupled to the machine in a bayonet type coupling arrangement in which the filter holder is 25 rotated relative to the machine to engage the filter holder and the machine. 005342355v2.doc intellectual property office of n.z. 3 0 OCT 2007 RECEIVED 005342355 13

12. A filter holder according to claim 10 further comprising a cam surface formed on the flange between the first engagement surface and the second engagement surface so that, on rotation of the filter holder relative to the machine, the cam surface causes the holder to be brought into sealed engagement with the machine. 5

13. A filter holder according to any one of claims 9-12 wherein the filter holder has a handle mounted thereto and wherein the second engagement surface is a concave shaped surface defining a detent arrangement requiring an application of lateral force to the handle in order to overcome the detent arrangement so as to enable the filter holder to be disengaged from the machine. > 10

14. An espresso coffee machine adapted to be coupled to a filter holder, the machine comprising at least one coupling formation adapted to interlock with a corresponding coupling formation on the filter holder, the at least one coupling formation on the machine comprising first and second engagement surfaces each adapted to engage with the coupling formation on the filter holder, the engagement surfaces being positioned and arranged such that 15 if the first engagement surface is engaged with the coupling formation on the filter holder, the filter holder is in sealed engagement with the machine and fluid under pressure discharging from the machine discharges through the filter holder, and i if the second engagement surface is engaged with the coupling formation on the filter holder, the filter holder is in non-sealed engagement with the machine and fluid under pressure 20 discharging from the machine is able to escape between the filter holder and the machine.

15. An espresso coffee machine according to claim 14 wherein the at least one coupling formation on the machine comprises a track having the first and second engagement surfaces thereon.

16. An espresso coffee machine according to claim 15 wherein the track is capable of 25 receiving a lug formed on the filter holder in a bayonet type coupling arrangement in which the filter holder is rotated relative to the machine to engage the filter holder and the machine. 005342355v2.doc intellectual property office of n.z. 3 0 OCT 2007 r fceived! 005342355 f 14

17. An espresso coffee machine according to claim 15 or 16 further comprising a cam surface formed on the track between the first engagement surface and the second engagement surface so that, on rotation of the filter holder relative to the machine, the cam surface causes the holder to be brought into sealed engagement with the machine. 5

18. An espresso filter holder according to any one of claims 14-17 wherein the filter holder has a handle mounted thereto and wherein the second engagement surface is a concave shaped surface defining a detent arrangement requiring an application of lateral force to the handle in order to overcome the detent arrangement so as to enable the filter holder to be disengaged from the machine. • 10

19. An assembly comprising an espresso coffee machine and a filter holder substantially as described herein with respect to any one of the embodiments as illustrated in the accompanying drawings.

20. A filter holder substantially as described herein with respect to any one of the embodiments as illustrated in the accompanying drawings. 15

21. A espresso coffee machine substantially as described herein with respect to any one of the embodiments as illustrated in the accompanying drawings. Dated : 26 October 2007 Freehills Patent & Trade Mark Attorneys Patent & Trade Mark Attorneys for the Applicant: 20 Sunbeam Corporation Limited intellectual property office of n.z. 3 0 OCT 2007 RECEIVED 005342355v2.doc