GB2400303A

GB2400303A - Cordless kettles

Info

Publication number: GB2400303A
Application number: GB0308399A
Authority: GB
Inventors: David Etherington
Original assignee: Salton Europe Ltd
Current assignee: Russell Hobbs Ltd
Priority date: 2003-04-11
Filing date: 2003-04-11
Publication date: 2004-10-13
Also published as: GB0308399D0

Abstract

A kettle (10) comprising a kettle vessel (12) and a power supply base (14) is provided. The power supply base (14) comprises a signalling device in the form of an indicator (24) to indicate current is flowing in a heating element (not shown) within the kettle vessel (12). By providing the indicator (24) within the power supply base (14) the kettle (10) can be positioned to allow a user to easily recognise that the kettle (10) is operational. Furthermore, by arranging the indicator (24) to respond to the flow of current in the heating element, the indicator (24) can give accurate information regarding the operational status of the kettle (10). In a particularly preferred embodiment the indicator (24) comprises light emitting elements distributed around the power supply base (14) to be visible from all directions.

Description

Improvements in and Relating to Kettles

Field of the Invention

The present invention relates to kettles, to power supply bases for kettles, and to methods of manufacture of power supply bases.

Background to the Invention

To provide a convenient apparatus for heating or boiling liquids such as water, electric kettles comprising a vessel for containing liquid and having an electric heating element within the vessel have been developed. To facilitate connection and disconnection of the heating element to an electric power supply a plug and socket arrangement can be used. The plug is located within a power supply base and the socket is located within the kettle vessel. Kettles having a separate vessel couplable to a power supply base by a plug and socket arrangement are referred to as cordless. In use, the power supply base is intended to be connected to a source of mains power, with the kettle vessel easily connectable to and disconnectable from the power supply base at the plug and socket. This makes for easy filling, heating and pouring.

For further ease of use the plug and socket arrangement can be designed to operate over a range of relative rotational positions of the kettle vessel and the power supply base. Precise alignment of the kettle vessel and the power supply base is then not required to make or break the connection at the plug and socket arrangement.

Electric kettle vessels may further comprise a signalling device including an indicator to show that the power supply to the heating element is switched on. Such an indicator can simply comprise a labelled switch in series with the heating element. However, a switch may apparently indicate that the kettle is switched on, when in fact no mains power is being supplied to the heating element. This could arise if the kettle is not plugged in, or if mains power to the kettle is interrupted for lo some other reason. In this case, the switch does not give an accurate indication that the kettle is operational.

Furthermore, cordless kettles having a plug and socket arrangement designed to operate over a range of relative rotational positions can supply power to the heating element over a range of relative rotational positions of the kettle vessel and the power supply base. This increases the chance that the indicator is not visible to a user when the heating element is switched on, due to the 2n increased chance of a relative position of user and kettle vessel in which the indicator is on the opposite side of the kettle vessel to the user. Figure 1 shows a prior art kettle 100 comprising a kettle vessel 120 and a power supply base 140. The kettle vessel 120 comprises a heating element (not shown) there within, a switch 160 comprising an indicator 240, and a socket 180. The power supply base 140 comprises a mains power lead 200, a mains plug 220, and a plug 260 arranged to cooperate with the socket 180. A problem can arise if the kettle vessel 120 is removed from the power supply base 140 with the switch switch still switched on, emptied, and replaced on the power supply base 140 without switching off the switch 160 so that power is still available to the heating element.

In this situation, due to his or her position, a user may not be able see the indicator 240 and therefore switch off switch 160 to protect the heating element from overheating.

It is an aim of preferred embodiments of the invention to overcome at least one of the disadvantages of the prior art, whether identified herein or otherwise.

lo Summary of the Invention

According to a first aspect of the present invention there is provided a kettle comprising a kettle vessel coupleable to a power supply base, wherein the kettle vessel comprises a heating element and the power supply base comprises a signalling device responsive to current flow in the heating element.

Suitably, the signalling device is arranged to indicate current flow in the heating element.

Suitably, the signalling device comprises a light emitting element. Suitably, the signalling device comprises at least one light emitting diode (LED). Preferably, the signalling device comprises at least two LEDs. More preferably, the signalling device comprises 3 to 8 LEDs.

Suitably, the light emitting element is coupled to at least one light output area by an optical fibre.

Suitably, the power supply base further comprises mains power leads. Suitably, the signalling device is coupled to the mains power leads by a non-contact power coupling.

Suitably, the signalling device is inductively coupled to the live wire of the mains power leads.

Suitably, the signalling device Is arranged around the power supply base. Suitably, the signalling device is arranged around the periphery of the power supply base.

Suitably, the signalling device is responsive to a cessation of current flow in the heating element.

Suitably, the signalling device is arranged to reset a mains power switch upon cessation of current flow in the heating element.

Suitably, the signalling device is arranged to indicate the kettle has boiled on cessation of current flow in the heating element.

According to a second aspect of the present invention there is provided a power supply base comprising an signalling device, wherein the power supply base is coupleable to a kettle vessel comprising a heating element, such that the signalling device is arranged in use to be responsive to a current flow in the heating element.

According to a third aspect of the present invention there is provided a method of manufacture of a power supply base coupleable to a kettle vessel comprising a heating element, the method comprising the step of: providing a signalling device within the power supply base, such that the signalling device is arranged in use to be responsive to a current flow in the heating element.

Brief Description of the Drawings

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:

Figure 1 shows a prior art kettle;

Figure 2 shows a kettle according to a first embodiment of the present invention with the kettle vessel disconnected from the power supply base; Figure 3 shows the kettle of Figure 2 with the kettle vessel connected to the power supply base and no current flowing in the heating element; Figure 4 shows the kettle of Figure 2 with current flowing in the heating element; Figure 5 shows a plan view of the power supply base of Figure 2; Figure 6 shows a side view of the power supply base of Figure 2; Figure 7 shows a partial circuit diagram for the kettle of Figure 2; and Figure 8 shows a partial circuit diagram for a kettle according to a further embodiment of the present invention; Figure 9 shows a kettle according to a second embodiment of the present invention with the kettle vessel connected to the power supply base; Figure 10 shows a perspective cutaway view of the power supply base of Figure 9; and Figure 11 shows a side cut-away view of the power supply base of Figure 9.

Description of Preferred Embodiments

Figure 2 shows a kettle 10 comprising a kettle vessel 12 and a power supply base 14. The kettle vessel 12 is releasably coupleable to the power supply base 14. The kettle vessel 12 comprises a heating element (not shown) there within, a switch 16, and a socket 18. The power supply base 14 comprises a mains power lead 20, a mains plug 22, a signalling device in the form of an indicator 24 and a plug 26.

The kettle 10 comprises a cordless kettle, and can operate with the kettle vessel 12 orientated at any rotational position about the line X-X relative to the power supply base as, indicated by the arrow 30 of Figure 2.

In use the mains plug 22 is coupled to a source of mains power, and power is supplied to the kettle 10 through the mains power lead 20. To use the kettle 10 to boil water, the kettle vessel 12 can be taken to a source of water for easy filling. The kettle vessel 12 is then coupled to the power supply base 14 using the plug 26 and socket 18, and the switch 16 is switched on. Current flows in the heating element to heat the water within the kettle vessel. The indicator 24 indicates that current is flowing in the heating element, thus informing a user that the kettle 10 is operational.

The indicator 24 is located within the power supply base 14, which is not usually moved during operation of the kettle 10. Therefore, the user can position the power lo supply base 14 so that it is easy to recognise that the kettle 10 is operational independent of the relative rotational arrangement of the kettle vessel 12 and the power supply base 14. As previously mentioned, if the switch of the kettle vessel or another indicator located on the kettle vessel is used to indicate that the kettle is operational, a use.- may not be able to ascertain whether the kettle is switched on when viewing the kettle from the opposite side to that of the indicator.

Furthermore, if the switch is switched on, but for some other reason no mains power can be supplied to the heating element, the switch does not give an accurate indication that the kettle is operational.

In the particularly preferred embodiment of Figure 2, the indicator 24 comprises light emitting elements distributed around the power supply base 24 to be visible from all directions about the line X-X. The line X- X is perpendicular to the plane of the power supply base 14.

Figures 3 and 4 show the kettle 10 with the kettle vessel 12 connected to the power supply base 14 with no current flowing in the heating element and with current flowing in the heating element respectively. In Figure 3, the switch 16 is in an off position and the indicator 24 is not illuminated. In Figure 4, the switch 16 is in an on position and the indicator 24 is illuminated.

Figures 5 and 6 show a plan and side view of the power supply base 14 respectively. The indicator comprises a plurality of light emitting elements located within the power supply base 14 and protected by a ring of light lo transmitting material. The light transmitting material is preferably a heat resistant plastics material, and may be of any suitable colour. The ring of light transmitting material is arranged to give a more uniformly illuminated appearance to the indicator 24 when a plurality of discrete light sources are used in the indicator 24. As can be seen in Figures 5 and 6. the indicator 24 is disposed around the entire periphery of the power supply base.

Figure 7 shows a partial circuit diagram for the kettles 10, 101. The circuit 40 is a partial circuit diagram as it does not show the mains power lead 20 or the mains plug 22. The circuit 40 comprises components of the kettle vessel 12 and components of the power supply base 14. The components of the power supply base 14 and the components of the kettle vessel 12 interface at the connection of the socket 18 with the plug 26, shown as reference 18, 26.

Referring now to Figure 9, a second embodiment of a kettle according to the present invention is shown. Figure 8 shows a kettle 101 comprising a kettle vessel 121, a switch 161, a power supply base 141 and a signalling device in the form of an indicator 241. Figures 10 and 11 show the power supply base 141 of the kettle 101 in more detail. The power supply base 141 comprises a plug 261, and the indicator 241. The indicator 241 comprises light emitting elements 242 in the form of LEDs, and a ring of light transmitting material 244.

The components of the kettle vessel 12 comprise a standard kettle circuit, including the switch 16 which is a steam sensing control switch, a bimetallic switch 13 for boil lo dry protection, a one-shot thermal fuse 15, and the heating element 19.

The components of the power supply base 14 include the indicator 24 and a transformer 25. The transformer 25 comprises a core 27 of a material having high magnetic permeability, for example ferrite, onto which at least one turn of the input mains power lead is wound. Also wound onto the core 27 is a wire coupled to the indicator 24.

In particularly preferred embodiments, the indicator 24 comprises a light emitting diode (LED) or a series arrangement of more than one LED. The LED(s) can therefore be distributed with their light emitting portions located around the circumference of the power supply base. At least two LEDS can be used to ensure the indicator 24 is visible from all around the power supply base. Most preferably, 3 to 8 LEDs can be used to give a more uniformly illuminated appearance to the indicator 24.

In practice, three turns of the input power lead and one turn of the wire coupled to the indicator 24 gives a suitable inductive coupling and voltage step down, enabling a relatively inexpensive core 27 and LED based indicator 24 to be used. As an alternative to inductive coupling, an electronics based current flow sensor could be used.

Other variations of the kettle 10 can be envisaged, for example with an indicator comprising a neon discharge lamp, an electro mechanical relay based display, a liquid crystal display or any other suitable display. The indicator may alternatively comprise a light emitting element that is made up from a single light source for example an LED, or incandescent bulb which is coupled to an optical fibre arrangement to transmit light from the light source to one or more light output areas. The light output areas can be located around the circumference of the power supply base, and may further be arranged to give a uniformly illuminated appearance when the indicator is turned on. In addition to low-power optical indicators, sound generating indicators could be used.

An alternative embodiment is shown in Figure 8 where like reference numerals are used to signify like elements to those shown in Figure 7. In this embodiment the signalling device comprises an indicator 24 and additionally comprises a unit 142 responsive to a change (i.e. a cessation or decrease) in the current flow in the heating element 19. In this embodiment the steam sensing switch 16 could be replaced with a steam sensor 162 which is not user accessible and a main power switch 163 is provided in the power supply base 14. Switching on the main power switch 163 in the power supply base 14 supplies current to the heating element 19 as long as the steam sensor 162 is also in an "on" configuration. The indicator 24 then indicates current is flowing in the heating element. When sufficient steam is produced to trip the steam sensor 162 to an "off" configuration the circuit to the heating element 19 is broken and the indicator 24 stops indicating current is flowing in the heating element 19. The cessation of current flow in the heating element 19 is sensed by the unit 142. The change in status sensed by unit 142 is used to reset the main power switch 163 and to activate a further "kettle boiled" display 143 on the kettle power supply base, and can be used for other uses. Alternatively, the unit 142 may Jo detect a changed status of the heating element current, and use this information in the same way.

In other embodiments the signalling device may comprise the unit 142 independent of the indicator 24.

The power supply base 14 could be used in combination with other kettle vessels 12, or with other cordless domestic appliances such as steam irons.

As described above, the signal]ing device is arranged in the power supply base 14 of the kettle 10. The signalling device is responsive to current flowing in the heating element from operating the mains power leads therefore the signalling device will only operate if the heating element is correctly able to receive mains power. If the heating element is inoperable the indicator 24 will not erroneously suggest that the kettle is working properly.

The power supply base of a kettle tends not to be moved by a user, therefore locating the signalling device on the power supply base makes it easy for the user to ascertain if the kettle is operational, as a relatively constant location for the signalling device is provided.

Furthermore, by distributing elements of the signalling device around the power supply base a user can view the signalling device from all directions, independent on the position of the kettle vessel 12.

Positioning the signalling device in the power supply base separates the signalling device from the water, heat and steam of the kettle vessel providing safety benefits and increasing its expected operational life. The weight of the kettle vessel is reduced making the kettle easier to lo use, and the design, moulding and assembly of the kettle vessel can be simplified.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, So equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features

disclosed in this specification (including any

accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

J

Claims: 1. A kettle comprising a kettle vessel coupleable to a power supply base, wherein the kettle vessel comprises a heating element and the power supply base comprises a signalling device responsive to current flow in the heating element.
2. The kettle of claim 1 wherein the signalling device is lo arranged to indicate current flow in the heating element.
3. The kettle of claim 1 or 2, wherein the signalling device comprises a light emitting element.
4. The kettle of claim 1, 2 or 3, wherein the signalling device comprises at least one light emitting diode (LED).
5. The kettle of claim 4, wherein the signalling device comprises at least two LEDs.
6. The kettle of claim 5, wherein the signalling device comprises 3 to 8 LEDs.
7. The kettle of claim 3, wherein the light emitting element is coupled to at least one light output area by an optical fibre.
8. The kettle of any preceding claim, wherein the power supply base further comprises mains power leads and the indicator is coupled to the mains power leads by a non-contact power coupling.
9. The kettle of claim 8, wherein the signalling device is inductively coupled to a live wire of the mains power leads.
10. The kettle of any preceding claim, wherein the signalling device is arranged around the power supply base.

lo
11. The kettle of claim 9, wherein the signalling device is arranged around the periphery of the power supply base.
12. The kettle of claim 1, wherein the signalling device is responsive to a cessation of current flow in the heating element.
13. The kettle of claim 12, wherein the signalling device is arranged to reset a mains power switch upon cessation of current flow in the heating element.
14. The kettle of claim 12, wherein the signalling device is arranged to indicate the kettle has boiled on cessation of current flow in the heating element.
15. A power supply base comprising a signalling device, wherein the power supply base is coupleable to a kettle vessel comprising a heating element, such that the signalling device is arranged in use to be responsive to a current flow in the heating element.
16. A method of manufacture of a power supply base coupleable to a kettle vessel comprising a heating element, the method comprising the step of: providing a signalling device within the power supply base, wherein the power supply base is such that the signalling device is arranged in use to be responsive to a current flow in the heating element.
17. A kettle substantially as described herein, with particular reference to accompanying Figures 2 to 11.

lo
18. A power supply base substantially as discussed herein, with particular reference to accompanying Figures 2 to 11.