The invention relates to a frother for milk based beverages and to a whisk for a frother..

Espresso based coffee drinks such as caffe latte and cappuccino have become increasingly popular and consumers want to be able to easily and reliably produce these drinks. Traditionally, baristas have been trained to use the steam generated by an espresso machine to heat and froth milk in a jug to produce the hot milk and froth required for these drinks. Producing the appropriate amount of hot milk and froth without burning the milk or damaging the jug requires some training or experience. Smaller espresso machines are also much harder to use to treat the milk.

A number of separate milk frothers have been produced which are suitable for home or small scale commercial use. EP1656866 discloses a frother with a tank to receive a milk-based liquid food with a magnetic beater. A magnetic beater driving system produces a magnetic field which drives the beater in rotation in the tank. The system, beater and a beater positioning unit break or prevent symmetrical circulation of the liquid around a median of vertical axis of the tank. Heating units are disposed in association with the tank for heating the liquid. This is used for preparing foam from a milk-based liquid food product. Further proposals are disclosed in CN20875556, CN208876158 and CN 109662619.

GB2454421 discloses a device for frothing milk that is provided with a rotating heating element to be inserted in the milk. The device is provided with a whisk attachment for producing froth and a paddle attachment for producing a more creamy finish.

A further problem with the known frothers is that the milk tends to burn on the element as when the frother has frothed the milk, the user immediately pours the milk out and a small residue remains behind, which burns on the element. If this is not cleaned quickly, the burnt on residue becomes difficult to remove and also affects future performance. The standard approach to this has been to reduce the temperature to which the milk is heated to around 60 C but at this temperature, the frothed milk is not suitable for use in other beverages such as hot chocolate, which would require a higher temperature to be palatable. GB2486872 represented a significant advance in the art of domestic milk frothers but is limited to use with milk. It is also a single cup design which is the standard capacity in the industry. Designing a milk frother with a higher capacity than the known milk frother designs requires that more power will need to be sent to the motor. Known whisk designs may not remain stable and/or may wear out too quickly with this increased power.

The present invention therefore seeks to provide a frother that can be used for producing a wider range and volumes of in particular milk based beverages.

According to the invention there is provided whisk means for a frother for producing a beverage comprising a tank for receiving a liquid, which tank has substantially vertical walls and a flat bottom, magnetic drive means adapted to drive whisk means, which whisk means is adapted to rotate in the liquid to mix the heating liquid, the frother further comprising heating means adapted to heat the milk or milk based liquid, the magnetic drive means being located outside of the tank, beneath the flat bottom of the tank, wherein the whisk means comprise a whisk comprising a plurality of coils, which whisk is mounted on a support, the whisk means further comprising first cover means which extend to substantially cover space above the whisk when the whisk is resting on the flat bottom and second cover means located below the whisk when the whisk is resting on the flat bottom.

Preferably, when the whisk is in use in a frother, the first cover means is arranged such that in use, powder does not settle on the coils of the whisk. Preferably, the cover means permit, in use, liquid to flow substantially unimpeded by the cover to and from the coils of the whisk.

Preferably the whisk has a width or diameter in a plane co-planar with the flat bottom, the first cover means having a width or diameter with substantially the same dimension or dimensions as the whisk.

Preferably the first cover means has a width or diameter greater than the width or diameter of the whisk.

Preferably the second cover means has a width or diameter with substantially the same dimension or dimensions as the whisk. Preferably, the second cover means has a width or diameter greater than the diameter of the whisk.

Preferably the second cover means is detachable from the whisk means enabling access to the whisk.

Preferably the whisk is releasably mounted on the whisk means.

Preferably the whisk means is provided with a collar to receive a mount support for the whisk.

Preferably the support comprises an annular upstanding wall, which, in use, sits on the flat bottom of the tank, which wall is joined by radial arms to an axial spindle on which support a whisk is rotatably mounted, which rotatably mounted whisk is rotatable by the magnetic drive means, wherein the support holds the whisk off the flat bottom of the tank, the whisk being held in position by the whisk means rather than the magnetic drive means.

Preferably the second cover means is releasably attached to the support by means of first and second spring clips.

The whisk design of the invention advantageously enables the production of frothers with larger volumes. It is also easier to clean than known designs.

Exemplary embodiments of the invention will now be described in greater detail with reference to the drawings in which:

Fig. 1 shows a perspective view of the frother;

Fig. 2 shows a perspective view of the whisk;

Fig. 3 shows an exploded view of the whisk from the lower side;

Fig. 4 shows an exploded view of an alternative embodiment of the whisk.

Figure 1 shows a perspective view of a milk frother having a tank 1 having a generally circular outer and inner circumference for receiving milk to be frothed and a handle 5. A magnetic drive means 2 is provided below the lower surface of the tank 1 , which drive means 2 is adapted to impart a drive to a removeable stirrer or whisk means 3 located in the tank without a mechanical connection member intruding through the wall of the tank 1. The removeable stirrer or whisk means 3 is supported on the base of the tank 1 to ensure that it remains centred and that the drive mechanism can impart drive to the stirrer.

A heating plate 4 is located beneath the base of the tank 1 , which heating plate is adapted to heat the milk in use. The frother is provided with control means adapted to control the actuation of the heating plate and also, independently, the actuation of the magnetic drive means. The control means can be either a single ECU or independent PCB’s. The magnetic drive means can also have more than one speed so that the liquid is not frothed, if for example follow on baby milk is being made.

In use, the control means are adapted to turn off the heating plate a predetermined time before the stirrer stops stirring so that the residual heat of the plate can be removed by the action of the stirrer passing the milk over it for the predetermined period of time. The length of time will depend on both the dimensions of the tank, the speed of the stirrer and the desired temperature of the milk. Typically, the predetermined length of time will need to be around 10s.

This particular arrangement has the attraction of permitting the milk to be heated to a higher temperature than would otherwise be possible but by the time the milk is poured from the frother the base of the tank will have cooled sufficiently that any residual milk that is left in contact with the tank will not burn. For example, in a frother of the invention it is possible to heat the milk to 75 C, which is suitable for making hot chocolate, whereas in most prior art devices, the milk is only heated to around 60 C as any higher temperature would result in unacceptable levels of milk burning on the surface of the frother.

Figure 2 shows a perspective view of whisk from above in accordance with a first aspect the invention. The whisk means 3 comprises an upstanding wall 7, which wall is joined by two radial arms 8 to an axial spindle 9. Each of the arms is provided with a cut out 12 in the region of the wall 7, which cut out 12 receives a clip 13 of a cover 14 to retain the cover in position. The spindle 9 extends above and below the radial arms 8. A whisk 10 is rotatably mounted on a rotatable drive shaft at the lower end of the spindle 9, which drive shaft is housed within the spindle 9. The wall shown is an annular wall but need not be a continuous annular wall. The radial arms 8 further comprise cover means 11 , which extend above the whisk 10 such that it substantially covers the whisk when viewed from above in a vertical orientation. The cover means may be located around 5-10mm above the whisk. The annular wall is provided with first and second location pips 15 located substantially equidistantly from each of the radial arms 8, which location pips 15 are adapted to engage with the wall of the frother so as to provide frictional resistance to rotation of the annular wall 7. The cover means can comprise a disc shape, so that liquid can flow unimpeded to and from the coils.

The cover means 11 prevent powder or flakes such as chocolate powder or baby milk powder or cocoa from settling on the coils of the whisk 10. The cover means 11 protect the spinning whisk in use from the chocolate flakes / powder as they are liable to melt thereby jamming the motor.

Figure 3 shows an exploded view of the whisk from the lower side. The underside of the cover 11 is provided with an axially located collar 16. The collar 16 is configured to receive the whisk 10 such that the whisk can be easily removed for cleaning. The collar need not comprise a continuous wall but could be segmented into two or more parts. The cover 14 comprises a first section 17 designed to cover the space below the whisk 10 in the installed position.

The section 17 is provided with two arms 18, each of which has a clip 13 at its distal end. The arms are angled upwards towards the height of the cover means 11 and the cut out 12. The angle of the upward arms provides a spring effect so that the arms have a snap fit with the cut outs 12. This enables the cover 14 to be easily removed for cleaning and also should it be desired to change the whisk means. Due to the increased volumes of this frother, it may be advantageous to use more than one whisk type, with each whisk having a different number of coils. Using different number of coils enables different volumes of air to be mixed into the milk in a given time interval so that the resultant drink has different amounts of foam.

Figure 4 shows an exploded view of an alternative embodiment of the whisk. As in Figure 3, the underside of the cover 11 is provided with three tabs 26. The tabs 26 are configured to receive the whisk 10 such that the whisk can be easily removed for cleaning. The cover 24 comprises a central section 25 which has a diameter substantially equal to, or alternatively, greater than the diameter of the coils of the whisk 10. The central section 25 is provided with three lozenge shaped protrusions on its lower side, which, in use, hold the central section of the whisk means off the bottom of the frother. The cover is provided with two arms 18, each of which has a clip 13 at its distal end. The arms are angled upwards towards the height of the cover means 11 and the cut out 12. The angle of the upward arms provides a spring effect so that the arms have a snap fit with the cut outs 12. This enables the cover 14 to be easily removed for cleaning and also should it be desired to change the whisk means.

The annular upstanding wall is provided with feet 28 adapted to raise the wall from the bottom of the interior of the frother.

The cover means 14 permit the interior of the tank 1 to be provided with either a polished stainless steel surface or alternatively a non stick coating. This also facilitates the magnetic drive means to run on for 20-30 seconds after the heating element is switched off. This enables the milk to be heated to a higher temperature suitable for hot chocolate drinks. The heat is dissipated throughout the milk and does not burn on the bottom surface of the container.

The radial arms 8 and cover means 11 will also interrupt the vortex that would develop due to the rotation of the whisk, which advantageously results in a better froth as well as increasing the working volume of the tank. The whisk means are also easily removable and are hence easy to clean. It would also be possible to ensure that the whisk means is dishwasher safe.

Although the whisk 10 has been described as a coiled spring whisks, different designs of whisk may be used such as curved, wavy or a flat disc with raised eyebrow vents each of which whisks can be easily exchanged depending on the beverage and nature of froth or foam desired. It would also be possible to use the tabs 26 in the embodiment of Figure 3 and the collar 16 in the embodiment of Figure 4.

There are a number of ways the cover 14 can be attached to the whisk means. It would be possible to clip over the outside or have vertical snap fits that attach to the support arms. The cover could also have a bayonet type fitting or a simple thread and so rotate into place.