WO2009024777A1

WO2009024777A1 - Electrical power connectors

Info

Publication number: WO2009024777A1
Application number: PCT/GB2008/002808
Authority: WO
Inventors: Robert Henry Hadfield; Michael Collinson; Antonio Martin Gaeta
Original assignee: Otter Controls Limited
Priority date: 2007-08-20
Filing date: 2008-08-19
Publication date: 2009-02-26
Also published as: GB0724092D0; CN201601348U; GB201004681D0; GB0814052D0; GB0716252D0; GB2465321A

Abstract

A multiple plug connector comprises a plurality of plug portions for simultaneous connection to a corresponding plurality of sockets. The spacing between the plug portions is adjustable to accommodate varying layouts of different socket faceplates. The plug portions may be connected to the same or different electrical loads within an electrical appliance, so that the electrical appliance may have a higher power rating than is obtainable through a single socket.

Description

Electrical Power Connectors

The present invention relates to electrical power connectors, and to electrical appliances having such power connectors.

Background to the Invention

Electrical domestic appliances may be plugged into a domestic power outlet or socket to draw electrical power from the mains electrical supply. Due to operating tolerances and safety regulations, such domestic appliances and the associated plugs and sockets are typically designed with a limited power rating. For example, a typical British 3-pin 230 V plug and socket is designed to provide 13 A (about 3 kW) through each outlet or socket. A typical European 230 V socket including an earth connector may be rated at up to 16 A, but devices for use with such sockets are normally rated at 10 A or less. A typical North American 3 -pin 120 V 15 A socket provides a lower power of about 1.8 kW.

Appliances having higher power ratings can be used in a domestic environment, but are normally permanently wired in to a higher power supply. For example, electric cookers may be wired into a 30 A supply. Wiring and rewiring such appliances requires a qualified electrician; this is a legal requirement in some countries, such as the UK.

Higher power socket connections are available, but are not usually provided in a domestic environment. For example, power supplies available in campsites, marinas and building sites may provide sockets rated at 16A or more, but these are not designed for direct connection of domestic appliances and are not compatible with plugs provided for such appliances.

In combined appliances incorporating an integrated plurality of electrical domestic appliances, careful design is required in order to avoid the combined appliances drawing more than the available maximum power. The Applicant's earlier application GB 0620057.0 describes circuitry to prevent or limit operation of both appliances concurrently, so that the maximum current drawn by the combined appliance does not exceed a maximum current available from a power outlet. Consequently, there is a need for providing additional power to electrical appliances in a safe and reliable manner, particularly for domestic appliances, and preferably without a requirement for rewiring.

Statement of the Invention According to one aspect of the invention, there is provided a combined plug comprising an integrated body housing at least two spaced apart plug portions for insertion into at least two corresponding electrical power sockets.

In another aspect of the invention, there is provided an appliance with a multiple plug or 'multiplug' for providing more than one power supply to the appliance so that a maximum power available to the appliance is increased.

According to another aspect of the invention, there is provided an appliance with a plurality of power requiring elements, each being individually connected to respective ones of a plurality of power supplies.

In yet another aspect of the invention, there is provided a combined appliance which is provided with more than one power supply so that a maximum power is available for each appliance.

Optionally, means may be provided in the multiplug or appliance to prevent only one of the plugs being electrically connected without another one of the plugs being electrically connected; this may avoid drawing too high a power from the one plug, or avoid making the unconnected plug live where both plugs are connected to the same load; this would present a problem if the pins on the unconnected plug were exposed, for example if the unconnected plug were mechanically disconnected.

According to yet another aspect of the invention, there is provided a combined plug assembly for use with a plurality of electrical power outlets having a respective plurality of connectors, the plug assembly comprising a body portion and a plurality of plug portions each slidably attached to the body portion for varying the spacing therebetween. Each of the plurality of plug portions includes a plurality of extended plug members for insertion into corresponding ones of the plurality of connectors of a respective electrical power outlet, each extended plug member having electrical connector means for electrical coupling to the body portion.

According to another aspect of the invention, there is provided a plug assembly for use with an electrical power outlet having a respective plurality of connectors, the plug

5 assembly comprising a housing, a plurality of extended plug members for insertion into corresponding ones of the plurality of connectors of the electrical power outlet, and handle means pivotally mounted to the housing for movement between a first position wherein the handle means is arranged to be grasped by a user so as to disengage the plug assembly from the electrical power outlet and a second position wherein the handle means is

) arranged in a stowed position. The handle means further comprises disengaging means arranged to abut a surface of the electrical power outlet when the handle means is moved to the first position such that disengagement of the plug assembly from the electrical power outlet is initiated.

Brief Description of the Drawings

5 Embodiments of the invention will now be described with reference to the drawings identified below.

Figure 1 is a schematic view of a kettle in a first embodiment of the invention.

Figure 2 is a schematic underside view of an element plate of the kettle of the first embodiment. Figure 3a is a perspective view of a multiplug of the first embodiment.

Figure 3b is another perspective view of the multiplug of the first embodiment from the plug's pin side.

Figure 4 is a perspective view showing the internal elements of the multiplug of the first embodiment. Figure 5 a is a perspective view of a multiplug in an alternative of the first embodiment.

Figure 5b is a perspective view of the multiplug in the alternative shown in Figure 5a from the plug's pin side. Figures 6a and 6b are perspective views showing the internal elements of the multiplug in another alternative of the first embodiment. Figure 6a shows the two plug parts arranged close together. Figure 6b shows the two plug parts in a spaced apart arrangement.

5 Figure 6c is a rear view of another variant of the first embodiment.

Figure 6d is a perspective view of yet another variant of the first embodiment, while Figure 6e shows cross sections of this variant.

Figure 7 is a schematic view of a kettle in a further alternative of the first embodiment.

) Figure 8 is a perspective view of a combined kettle and toaster in a second embodiment of the invention.

Figure 9 is a perspective view of an exemplary duplex socket and a multiplug of a third embodiment of the invention.

Figure 10 is another perspective view of the multiplug of the third embodiment 5 from the plug's pin side.

Figure 11, which comprises Figures 11a and l ib, is a perspective view of the multiplug of the third embodiment from the plug's pin side illustrating the variable spacing between the adjustable plug parts.

Figure 12 is an exploded perspective view showing the component parts of the multiplug of the third embodiment from the plug's pin side.

Figure 13 is another exploded perspective view showing the internal elements of the plug parts of the multiplug of the third embodiment.

Figure 14 is a perspective view of the body of the multiplug of the third embodiment. Figure 15 is a perspective view of the body of the multiplug of the third embodiment, illustrating the internal elements of the body of the multiplug. Figure 16 is a perspective sectional view through the multiplug of the third embodiment, illustrating the internal elements of the body of the multiplug of the third embodiment.

Figure 17, which comprises Figures 17a to 17c, is a perspective view of a multiplug of a fourth embodiment of the invention.

Figure 18 is another perspective view of the multiplug of the fourth embodiment.

Figure 19 is an exploded perspective view showing the internal elements of the plug parts of the multiplug of the fourth embodiment.

Figure 20 is another exploded perspective view showing the component parts of the multiplug of the fourth embodiment from the plug's pin side.

Figure 21 is another exploded perspective view illustrating the internal elements of body of the multiplug of the fourth embodiment.

Figure 22 is an illustration of a plurality of various exemplary duplex outlets. Figures 23a to 23c are perspective views of an alternative plug part. Figures 24a and 24b are perspective views of another alternative plug part, respectively separated from and connected to a back box.

Figures 25a to 25c are perspective views of a plug part being mounted onto a back box, in another alternative embodiment.

Figure 26 is a perspective sectional view of the plug part mounted in the back box, in the alternative embodiment of Figure 25.

Figures 27a and 27b are perspective views of the plug part of the alternative embodiment, using leaf spring terminals.

Figure 28 is a schematic diagram of a variant using coil spring loaded terminals.

Figures 29a to 29d are perspective views of multiplugs for use in different countries.

Figure 30 is a perspective view of a multiplug with a connector. Figure 31 is a perspective view of the multiplug with the connector for connection to a power inlet of an appliance.

Figures 32a to 32c are perspective views of multiplug extension leads, in different variants.

Figures 33a and 33b are perspective views respectively of a power outlet and a multiplug having complementary projections and recesses, while Figure 33c is a side view of an attempted incorrect connection between the multiplug and the power outlet.

Figures 33d and 33e show further variants having complementary projections and recesses.

Detailed Description of the Embodiments First embodiment

As shown in Figure 1, the first embodiment comprises a kettle 1 having a water reservoir portion 2 supported on an integral base portion 3. In this embodiment, the base portion 3 has a single power cable or conduit 9 for connection to a power source, such as the mains power supply, via a multiplug 10 to supply power to heating elements of the kettle 3 from two power outlets or sockets of a socket faceplate 31a. The kettle 1 may include an element plate 4 forming the bottom of a water reservoir of the kettle and having one or more heating elements on the underside thereof. The heating elements may be of the same type or of different types, for example thick film or sheathed heating elements. The element plate may be of stainless steel.

Figure 2 is a schematic underside view of an embodiment of the element plate 4 of the kettle 1. In this embodiment, the element plate 4 of the kettle 1 carries two separate sheathed heating elements 8a and 8b. In this embodiment, the heating elements are coplanar and concentric but many other configurations and layouts are possible. For example, the sheathed heating elements 8a and 8b may be of substantially the same shape and size and arranged one above the other. Where the heating elements are thick film heating elements, these may be coplanar so that they can be deposited simultaneously during manufacture. Alternatively, the heating elements may be deposited in separate layers. Each of the heating elements 8a and 8b is connected to a corresponding one of the two power supplies provided by the power cable 9 and draws power from its own power outlet or socket when the multiplug 10 is plugged into the power outlets or sockets. By drawing power from two separate power outlets or sockets, the kettle 1 is able to provide twice the amount of power compared to using a single power lead, while remaining within the power rating of the power supply at each power outlet or socket.

The kettle 1 may also include a switch, thermostat and control circuitry (not shown) for controlling actuation and operation of the kettle 1.

In the example socket faceplate 31a illustrated in Figure 1, the power outlets or sockets each have a corresponding switch 33 located on the right hand side of the respective outlet or socket. Figure 3a shows a more detailed perspective view of the multiplug 10 plugged into adjacent sockets of a socket plate 31b. Figure 3b shows a perspective view of the multiplug 10 from the plug's pin side. Figure 3a shows a different socket face plate 31b from the socket face plate shown in Figure 1 , the socket face plate 3 Ib shown in Figure 3b having a different layout in which the switches 33 are arranged adjacent each other and toward the centre of the socket plate 31b. Of course, the illustrated socket faceplates 31a and 31b are provided merely as examples of two different layouts of coplanar outlets or sockets. Many different layouts are envisaged, depending for example on the relative placement of switches and outlets or sockets, and the spacing between sockets and • switches. The multiplug 10 of the present embodiment is adjustable to accommodate these different layouts and variations.

As shown in Figures 3 a and 3b, the multiplug 10 comprises an integrated body having two plug parts 10a and 10b. Each plug part 10a and 10b comprises respective sets of pins or legs for insertion into corresponding holes of a power outlet or socket. The individual plug

> parts 10a and 10b have a form and size similar to standard plugs so as to be able to fit into a standard power outlet or socket. The plug parts 10a and 10b may be arranged at a fixed spacing to accommodate a standard dual socket face plate 31a, 31b layout so that the pins or legs of both plug parts 10a and 10b can be concurrently inserted into two adjacent power outlets or sockets. A gap is provided between the two plug parts 10a and 10b to accommodate the switches 33 which may be located adjacent the power outlets or sockets. Alternatively, the two plug parts 10a and 10b may be arranged to allow for adjustments to vary the spacing between the plug parts 10a and 10b to accommodate variances in spacing between adjacent power outlets or sockets or to accommodate for the locations of adjacent on-off switches 33, as illustrated by the different power socket face plates 31a and 3 Ib. As an example, the two plug parts 10a and 10b may be slidably attached to a common part or housing of the integrated body.

Figure 4 is a perspective view of the multiplug 10 without its protective cover. As shown, the two separate parts 10a and 10b of the multiplug 10 are connected by interlocking extended members as discussed below. The first part 10a comprises plug elements 13a,b,c for a first part of the multiplug 10 to be inserted into respective openings of a first socket (not shown), and the second part 10b comprises plug elements 14a,b,c for a second part of the multiplug 10 to be inserted into respective openings of a second socket adjacent the first socket. As discussed above, the first and second sockets need not be immediately adjacent one another, but may be separated by respective switches or by a further socket or sockets. Each of the two parts 10a and 10b includes end walls, one full sidewall, one partial sidewall and a generally flat bottom surface. A generally flat top surface is also provided by the protective cover which has been removed to show the inside of the multiplug 10. The partial sidewalls of the two parts are intersected by end walls of first and second extended members 15,17 which extend from the respective partial sidewalls. The end walls 15 of the second extended member are formed further apart than the end walls 17 of the first extended member to allow for slidable engagement of the two extended members. This arrangement allows the two interlocked parts to be slidably adjusted to allow for variations in distances between two receiving sockets, as discussed above. Openings in the bottom end walls 15,17 of both extended members allow for a cable 9 to be inserted into the multiplug 10. In this embodiment, the cable 9 includes two separate ground wires 5a and 6a, two separate live wires 5b and 6b, and two separate neutral wires 5c and 6c insulated from each other and shielded from inadvertent contact by an insulating sheath. As those skilled in the art will appreciate, the size of wire will depend on the loading of the individual power requirements. The insulating sheath is removed at an end portion of the cable 9 to expose the six separate wires for electrical connection to respective terminals of the multiplug 10 as discussed below. In this embodiment, the multiplug 10 is designed for use with coplanar standard UK three pin sockets. Accordingly, the two parts 10a and 10b of the multiplug 10 each include with a ground terminal 13a, 14a, a live terminal 13b, 14b and a neutral terminal 13c, 14c which extend through openings in the bottom surface and are configured as a standard electrical plug for insertion into a standard electrical socket. Each pair of ground 13a, 14a and live terminals 13b, 14b is electrically connected to a respective fuse 21 designed for 240 V applications, such as a 13 A fuse. Each of the terminals may be electrically connected to a respective one of the wires from the cable 9 for example by receiving an unsheathed end portion of a wire in a wire receptacle portion and securing the wire in place by way of a screw. In this way, the first ground wire 5 a, live wire 5b and neutral wire 5 c will be connected respectively to the ground terminal 13 a, live terminal 13b and neutral terminal 13c of the first part 10a. The second ground wire 6a, live wire 6b and neutral wire 6c will be connected respectively to the ground terminal 14a, live terminal 14b and neutral terminal 14c of the second part 10b. In an alternative, it may be possible to reduce the number of wires to five wires if a common earth wire is shared by the ground terminals 13 a, 14a. In another example, the multiplug 10 may not require an earth wire, and the number of wires may be further reduced to just four wires. ha the above embodiment, a single power cable 9 extends from the multiplug 10 into the kettle, and the power cable 9 comprises six wires which are gathered together and contained within a single sheathed power cable 9. As illustrated in Figures 5 a and 5b, in another alternative, the terminals 13a,b,c of the first part 10a may be connected to three corresponding wires contained in a first power cable 9a and the terminals 14a,b,c of the second part 10b may be connected to three corresponding wires contained in a second power cable 9b. The two power cables 9a and 9b may be passed through a bifurcated connector 41 to join the separate cables together.

As another alternative illustrated in Figures 6a and 6b, the respective ground, live and neutral terminals may be centrally coupled within the multiplug 10 and connected to a single respective ground, live and neutral wire 9a,b,c, instead of connecting the terminals 13a, 13b, 13c, 14a, 14b, 14c to respective separate wires within the multiplug 10. Figure 6a illustrates the multiplug 10 where the two parts 10a and 10b have been adjusted so that the plug elements 13a,b,c of the first part 10a are arranged in close proximity to the plug elements 14a,b,c of the second part 10b, for example, to accommodate the socket faceplate 31a illustrated in Figure 1. Conversely, Figure 6b illustrates the multiplug 10 where the two parts 10a and 10b have been adjusted so that the plug elements 13a,b,c of the first part 10a are more spaced apart from the plug elements 14a,b,c of the second part 10b, for example, to accommodate the socket faceplate 31b illustrated in Figure 3a. The ground terminals 13 a, 14a of each of the plug parts 10a, 10b of the dual plug 10 are electrically connected by a pair of slidably engaging bars 23, further connected to a cable receptacle portion 25 for receiving an unsheathed end portion of the ground wire 9a from the cable 9. Similarly, the live terminals 13b, 14b of each of the plug parts 10a, 10b of the dual plug 10 are electrically connected by a pair of slidably engaging bars 27, further connected to a cable receptacle portion 29 for receiving an unsheathed end portion of the live wire 9b from the cable 9. The neutral terminals 13c, 14c of each of the plug parts 10a, 10b of the dual plug 10 are also electrically connected by a pair of slidably engaging bars 31, further connected to a cable receptacle portion 33 for receiving an unsheathed end portion of the neutral wire 9c from the cable 9. In this less preferred alternative, it may be necessary to include an interlock (not shown) in the multiplug such that unless power is being provided through both plug parts 10a and 10b, the multiplug will cut out and be inoperable to avoid overloading a single power outlet or socket, or to prevent the unconnected plug from becoming live if mechanically unconnected. One method for this would be to make the supply of power from plug parts 10a and 10b interdependent, such that the plug parts supply power separately but are linked to prevent power from being supplied from one plug part but not from the other plug part. In other words, the plug parts are electrically separate but are linked together. For example, an electromechanical switch such as a relay, or an electronic circuit, that is activated by the supply of power from plug part 10a may act as a switch between the plug part 10b and the appliance; a similar arrangement activated by the supply of power from plug part 10b controls the supply of power from plug part 10a. This interdependency would need to be activated when the plug parts are electrically connected to the wires but before the plug parts are connected to supply power to a combined load. Means for enabling this interdependency may be provided within the multiplug 10, within the appliance, or in a separate module connected between the multiplug 10 and the appliance. Figure 6c shows another alternative of the first embodiment, similar to the embodiment of Figure 4 but with the cord 9 fixed to the plug part 10b and having wires for connection to the plug part 10a, sufficiently long to allow for movement of the plug part 10a relative to the plug part 10b. The plug part 10a is slidably mounted relative to the plug part 10b, for 5 example by means of a slidable mechanical connection between the backs of the plug parts 10a, 10b, not shown in Figure 6c.

Figures 6d and 6e show another variant of the first embodiment, similar to the embodiment of Figures 6a and 6b in that a sliding electrical connection is provided between the plug parts 10a and 10b. However, in this variant the cord 9 is fixed to the plug part 10b and ) sliding electrical connections are made between conductive bars 23a, 27a, 31a in a rear section of plug part 10a and corresponding sliding contacts 23b, 27b, 31b in the plug part 10b.

In other variants, alternative means may be provided for electrical connection between the plug parts 10a and 10b while allowing adjustment of the spacing between the plug parts 5 10a, 10b, such as coiled wires, springs, or telescopic connections.

As a further advantage, the plug parts 10a and 10b of the multiplug 10 are designed such that the multiplug 10 cannot be installed into two power outlets or sockets of a standard adapter as commonly used to provide additional outlets or sockets, because in such adapters the additional outlets or sockets are provided on different non-planar faces of the

) adapter. Nevertheless, as discussed in the alternatives above, an interlock may be provided in the multiplug to prevent use of the multiplug when plugged into only one of the outlets or sockets of such an adapter. The interlock may be a mechanical or an electrical interlock. The interlock is preferably provided in embodiments when more than one plug part of the multiplug is connected to a common load, so that the terminals of the plug parts are

5 interconnected.

Figure 7 illustrates a further alternative in which the base portion 3 has two power cables 43 a and 43b for dual connection to a power source via corresponding plugs 45 a and 45b to supply power to the kettle 3. In this less preferred alternative, it may be necessary to include an interlock (not shown) in the kettle 1 such that unless power is being provided through both power cables 43 a and 43b, the kettle 1 will be inoperable to avoid overloading a single power outlet or socket.

In the above embodiment, the base portion 3 is provided as an integral part of the kettle 1. It is envisaged that the kettle may instead be a cordless kettle comprising a cordless base i portion 3 including a cordless electrical connector (not shown) adapted to supply two power conduits to the kettle 1 or to handle a larger current (at present, typical cordless connectors can only handle up to 13 A), and connected to both of the power supplies. In this alternative, the cordless kettle 1 includes a corresponding cordless electrical connector (not shown) arranged so that, when the kettle 1 is positioned on the base portion 3, the

) respective cordless electrical connectors are connected together to supply electrical power to the kettle 1 from both power supplies.

In the above embodiment, the kettle 1 comprises two separate heating elements 8a and 8b. In an alternative, the kettle 1 may instead comprise a single heating element. For example, in the UK, the single heating element may be rated at 6 kW and arranged to draw power > from both power outlets or sockets. In this less preferred alternative, it may be necessary to include an interlock (not shown) in the multiplug 10 or kettle 1 such that unless power is being provided from both power outlets or sockets, the kettle 1 will be inoperable to avoid overloading a single power outlet or socket, or making the unconnected plug live.

The above embodiment and alternatives provide a kettle with an increased maximum ) power usage, but aspects of the invention are applicable to other domestic electrical appliances and particularly advantageous to high-power domestic appliances such as air- conditioners, electric heaters, water heaters such as under-sink or over-sink heaters, showers, portable or temporary showers, heated jet washers, Jacuzzis, saunas, immersion heaters and cookers.

5 The invention is preferably embodied in appliances that benefit from intermittent use and therefore are not operated on full power for an extended period of time, such as kettles, food mixers, beverage making appliances, cooking appliances, power tools, garden equipment, and such like. The invention is also particularly advantageous to appliances that need rapid heat-up or recovery and then rely on thermostats to maintain and control operation of the appliance. Examples of such appliances are ovens, kilns, water boilers, kettles, refrigerators, battery chargers, toasters, deep fat fryers, grills, griddles, teppanyaki plates, waffle makers and electric barbecues. As those skilled in the art will appreciate, depending on the type of appliance, the electrical loads need not be heating elements as in a kettle. Instead or additionally, the electrical loads may consist of pumps, motors, cooling elements and such like. One example may be a fridge freezer including extra cooling elements to provide faster freezing or an extra heating element to provide for example a hot drinks dispenser. Additionally, an appliance need not comprise two electrical loads of the same type or function, but instead may comprise two different types of electrical load. For example, a heated food mixer appliance may comprise a motor to drive the mixer and a heating element to keep the food hot.

As those skilled in the art will appreciate, although many of the example appliances discussed above are domestic appliances, the present invention is equally applicable to other types of appliances. For example, a semi-commercial vending machine may benefit from drawing power from two power sockets to enable additional functionality such as the ability to dispense two items at the same time or faster dispensing. As another example, it is advantageous to provide power from two power sockets to larger wattage appliances such as: battery chargers for electric cars, golf caddies, milk floats and other electric vehicles to speed up charging; kitchen appliances such as mixers, food processors and ice cream makers; garden appliances such as tree or plant shredders, mowers and hedge trimmers; heaters such as fan heaters, radiant heaters and oil filled radiators; air- conditioning units; office equipment such as document shredders; high-powered computers such as servers, mainframes and supercomputers; and tools and appliances used in the construction industry, such as concrete mixers, circular saws, drills and other power tools which typically have higher power requirements and therefore may benefit from the present invention when used in a domestic setting for example.

In another alternative, the invention is also particular advantageous to appliances which include flow through heaters such as coffee/espresso/cappuccino machines, washing machines, on-demand hot water dispensers and the like. Flow through heaters may benefit from an increased power supply, for example by using 4.5 kW of power via two power leads (and an optional interlock, as discussed in the alternatives above) to increase the flow by 50% compared to using just 3 kW via a single power cable. In another example, two separate flow-through heaters may be arranged in a linear sequence with the heated output from the first flow through heater running into, the second flow through heater. Alternatively, the two separate flow through heaters may be provided in a parallel arrangement. In a further alternative, the improved flow rate may be achieved by utilising two separate outlets from a flow through heater. In yet another alternative, a two-part appliance may utilise a first flow through heater to pre-heat a volume of water and a second flow through heater to heat up the pre-heated water to the desired temperature. As another example, a two-part espresso machine may utilise a first flow through heater to heat up the milk and a second flow through heater to heat up the water or coffee for the espresso. As yet another example, a two-part appliance may comprise a cooler to supply chilled liquid and a heater to supply warm or hot liquid.

The above embodiment and alternatives also advantageously allows larger sized appliances to be more mobile instead of having to be permanently wired into the main power supply in order to meet its power requirements. For example, a large water heater urn need not be permanently wired into the main power supply but instead could be situated on a work top and plugged into two power outlets or sockets while still providing the high level of power required to operate.

The present invention may also advantageously be used to power a caravan using two existing sockets in absence of a high power supply typically found in campsites for providing current up to 16 amps, for example. As a further advantage, a domestic setting such as the kitchen may be fitted with double plug sockets throughout to provide increased flexibility when it comes to installing or re-arranging high powered appliances, such as a high power cooker, fridge freezer, washing machine and dryer, etc. For example, in the UK, it is not a straightforward matter to move the location of a cooker because there is a legal requirement for a qualified electrician to wire in the cooker in the new location. Consequently, it is advantageous to provide the cooker with a multiplug (or a suitable converter to a multiplug) in accordance with the present invention in preparation for the appliance delivery so that the appliance can be plugged into any double socket located in the kitchen.

In the above embodiment, the base portion 3 of the kettle included two heating elements. In a preferred embodiment, the individual elements in the appliances are designed to use standardised sizes so that the internal components need not be specially designed or manufactured. For example, both of the heating elements may be standard 3 kW elements which may provide for more rapid heating compared to single element kettle. In another example, one of the heating elements may be a standard 3 kW element and the other heating element may be a standard 1 kW element, which may provide for an improved heating up mode of operation utilising a combined 4 kW of power, followed by a keep warm mode of operation utilising just the lower power heating element. In this way, the present embodiment advantageously provides for a higher wattage appliance using a plurality of standard lower wattage components. This same advantage can be carried forward into other embodiments - thus providing the manufacture with significant savings on both the individual components and the wiring harnesses. Enabling individual aspects of each appliance to be treated as lower (standard) wattage, it will also allow the manufacturer to uses standard production techniques, test equipment and test specifications. This advantage will carry through at each stage of the supply chain. hi a further alternative, the multiplug may include more than two plug parts. For example, a larger appliance may include four power loads each connected to a corresponding power supply and the resulting appliance may utilise four times the amount of power compared to an appliance with a single plug, without exceeding the power rating of the power supply at each of the four power outlets or sockets.

As those skilled in the art will appreciate, plug and socket design will vary depending on the country and location of intended use. For example, power outlet or socket faceplates in Europe and North America typically do not include corresponding on-off switches. Therefore, it may not be necessary to vary the spacing of the plug parts 10a and 10b to accommodate any switches. It may be further necessary to accommodate for other variations to the plug parts 10a and 10b such as different shapes (round plug heads are sometimes used), variable widths, varying clockwise or counter-clockwise angles, varying angles of the plug faces (angled socket face plates are sometimes used), or varying orientation (such as vertical rather than side-by-side). The first embodiment and alternatives advantageously provide a single unit incorporating a multiplug having two plugs so that either both plugs are plugged in or both plugs are disconnected. In this way, a user is prevented from inadvertently leaving one of the two plugs plugged into the power supply while the other of the two plugs is loose and potentially live. Furthermore, by forcing the user to disconnect both plugs at the same time, this ensures that the appliance will be fully isolated from the power supply.

Second embodiment

As shown in Figure 8, the second embodiment provides a combined toaster 51 and cordless kettle 53 as an integrated appliance 55. The integrated appliance 55 comprises a base unit 57 comprising the toaster 51 and an integral base 59, for supporting and providing power to the kettle 53. The base unit 57 has a power cable 61 for connection to a power source via a multiplug 10 of the first embodiment. The multiplug 10 provides two separate power supplies to the integrated appliance 55, one power supply being provided to the toaster 51 and the other power supply being provided to the cordless kettle 53 as discussed below.

The integral base 59 provides a substantially horizontal surface including a cordless electrical connector (not shown), such as the CS4 connector supplied by Otter Controls Ltd and described in patent publication WO 94/06185, and is connected to one of the two power supplies from the multiplug 10. The kettle 53 includes a corresponding cordless electrical connector (not shown) arranged so that, when the kettle 53 is positioned on the base 59, the respective cordless electrical connectors are connected together to supply electrical power to the kettle 53 via the multiplug 10 plugged into the two power outlets or sockets.

The socket faceplate 31a illustrated in Figure 8 shows an exemplary layout of the outlets or sockets and switches 33. As discussed above, different layouts are possible depending on the socket faceplate and the multiplug 10 is adjustable to accommodate the various possible layouts.

The above embodiment and alternatives provide a combined kettle and toaster, but aspects of the invention are applicable to other domestic electrical appliances, for example a combined toaster and coffee maker, a combined kettle and espresso maker, or a combined microwave and grill appliance.

Third embodiment

As shown in Figures 9 and 10, a multiplug assembly 101 according to this embodiment comprises a back box 103 having slidably mounted thereon a pair of plug parts 105a and 105b. Each plug part 105a and 105b comprises respective sets of plug pins 107 for insertion into corresponding outlet sockets 109 of a duplex power outlet 111. As will be described below, the plug parts 105 are slidably adjustable to allow for adjustments to vary the spacing between the plug parts 105 a and 105b to accommodate variances in spacing between adjacent outlets and/or to accommodate for the locations of adjacent isolator switches 113, so that the plug pins 107 of both plug parts 105a and 105b can be concurrently inserted into the two outlets of the duplex power outlet 111.

In this embodiment, the plug parts 105 effectively provide a gap of about 10 mm between the back box 103 and the duplex power outlet 111. In this way, the back box 103 of the multiplug assembly 101 avoids contact with any switches adjacent to the outlets, such as the isolator switches 113 illustrated in Figures 9 and 10. The gap also advantageously allows a user to hold or grip the back box 103 when withdrawing the multiplug assembly 101 from the duplex power outlet 111. It will be appreciated that the gap between the back box 103 and the duplex power outlet 111 should be at minimum 5 mm.

Figure 11, which comprises Figures 11a and lib, is a perspective view of the multiplug assembly 101 from the plug pins 107 side, illustrating the variable spacing between the adjustable plug parts 105. Figure 11a illustrates the plug parts 105 arranged at positions closest to each other to allow insertion of the two plug parts 105a and 105b into a duplex outlet with respective outlets arranged more closely together. The position illustrated in Figure 11a may also allow access, via fuse covers 121 provided in a rear face of the back box 103, to respective fuses 123 coupled to the power supply provided through each plug part 105a and 105b. In the illustrated embodiment, the fuses 123 are provided at respective ends of the back box 103 of the multiplug assembly 101. The fuses 123 may be designed for 240 V applications such as a 13 A fuse. Figure 1 Ib illustrates the plug parts 105 arranged at positions furthest apart from each other to allow insertion of the two plug parts 105a and 105b into a duplex outlet with respective outlets arranged more spaced apart.

Referring back to Figures 9 and 10, latches 117 may be provided on the plug parts 105a and 105b to prevent sliding of the plug parts 105 when the latches 117 are engaged with ridges 118 running across the width of the upper and lower surface of the back box 103 of the multiplug assembly 101. In this embodiment, two latches 117 are provided on each plug part 5, one provided on an upper surface of the plug part and one provided on a lower surface of the plug part, hi use, the latches 117 must be pressed down to release the lock mechanism in order to enable slidable adjustment of the respective plug part 105 along the length of the back box 103. As those skilled in the art will appreciate, it is advantageous to prevent any sliding movement when the multiplug assembly is in use. Accordingly, a plug rod or other suitable means may be provided to prevent the latches from becoming disengaged or unlatched when the multiplug assembly 101 is plugged into the outlet 111. A further advantage of preventing sliding movement when the multiplug assembly has been inserted into plug sockets is that the respective plug parts are prevented from effectively clamping against the holes of the sockets which would cause difficulties in disengaging the multiplug from the sockets. Alternatively, clamping may be avoided by providing for discrete increments of slideable movement. This may be achieved, for example, by providing a plurality of grooves on the back box, such as illustrated on the multiplug illustrated in Figure 9, for engagement with a protruding tooth provided on each of the arms of the plug parts. The protruding teeth may have a smaller thickness than each groove thereby providing a small amount of play, or may be resilient, such that clamping between the plug pins and socket holes is prevented.

Alternatively, only one of the plug parts 105 need be locked or latched against sliding relative to the back box 103; the plug parts 105a, 105b need only be aligned with and inserted into the sockets, and the locking of only one of the plug parts 105 will prevent sliding of the back box once the plug parts are plugged into the sockets, hi another alternative, neither plug part 105 may be lockable against sliding relative to the back box, but this is less preferred since the back box 103 would then be slidable when both plug parts 105 are plugged in. An indicator light 119, such as an LED, may also be provided for each plug part 105 a and 105b on a front face of the back box 103 which is opposite from the plug pins 107. The indicator light may be arranged to indicate, for example, when power is being supplied to the respective plug part 105, when an appliance is drawing power through the respective plug part 105 and/or the status of a respective fuse 123, such as whether the fuse 123 has blown.

An insulating sheath 125 extends from the back box 103 of the multiplug assembly 101 for carrying power supply wires to a connected device, as will be discussed in more detail below. The insulating sheath is securely connected to the back box 103 by a reinforced cord- grip portion 127. As an alternative, the reinforced cord grip portion may instead be provided as a rotatable cord outlet (as typically found on domestic irons) which can rotate or pivot freely about the connection point with the back box 103. As yet another alternative, a self-forming cord outlet may be provided which provides flexibility in forming the output wires to any desired shape as required.

The individual plug parts 105 a and 105b will have a form and size similar to standard plugs so as to be able to fit into a standard power outlet of a typical duplex outlet 111. As those skilled in the art will appreciate, many different types of duplex outlets exist. Figure 22 illustrates five different types of duplex outlets each having two sets of outlet sockets 109 for receiving plug pins of respective plug parts 105. Example duplex outlets 111-1, 111-2 and 111-3 illustrate different locations of the respective outlets and isolator switches 113 provided adjacent respective outlets, and consequently different distances between the sockets of the respective outlets. The vertical position of the outlets may also vary. Duplex outlets 111-4 and 111-5 illustrate example outlets with Residual Current Device switches 115 provided between the respective outlets and again resulting in different distances between the sockets of the respective outlets. The multiplug assembly of the present invention may be configured to accommodate all standard and typical UK duplex outlets.

Figures 12 and 13 illustrate exploded perspective views showing the component parts of the multiplug assembly 101 of the present embodiment. As shown, each plug part 105 is formed by a housing 129 having two extending arms 131 and 133 arranged to engage the top and bottom surfaces of the back box 103 of the multiplug assembly 101. When the multiplug assembly 101 is being assembled, the housing 129 of the plug part 105 engages the back box 103 and the extending arms 131 and 133 are permanently connected to a plug strap 135, for example by ultrasonically welding the plug strap 135 to the extending arms 131 and 133 or by way of a security screw (not shown) which is made non-accessible or inoperable subsequent to fixing of the plug strap 135 to the housing 129 of the plug part 105. In this way, the multiplug assembly 101 is effectively non-rewireable by a user to prevent the user from crossing over the poles and wires contained within the back box 103 of the multiplug assembly 101. In this case, it will also be necessary to connect the wires to the buss bars with permanent connections which are non-rewireable so that the internal components cannot come loose.

In this embodiment, the multiplug assembly 101 is designed for use with coplanar standard UK three pin sockets. Accordingly, the plug pins 107 of each plug part 105a and 105b include a ground terminal 107a, a live terminal 107b and a neutral teπninal 107c which extend through openings in the housing 129 and are configured as a standard UK electrical plug for insertion into a standard UK electrical outlet. In this embodiment, the plug pins 107 are electrically connected to the back box 103 of the plug assembly 101 via male tabs 137 formed at one end of the plug pins 107 opposite to the end which is inserted into a socket 109. As illustrated in Figure 13, the three male tabs 137 of a plug part 105 are provided in a linear, parallel, spaced apart arrangement and fit into respective slots 139 provided on a rear face of the back box 103 of the multiplug assembly 101, for slidable engagement with respective electrical components in the back box 103 as will be discussed below. The earth terminal 107a is provided with a male tab 137 which extends substantially straight along from the end of the terminal 107a and is received by a first slot 139a. The live terminal 107b is provided with a male tab 137 which extends from an arm connected to a lower surface of the terminal 107b and is received by a second slot 139b arranged below the first slot 139a. The neutral terminal 107c is provided with a male tab 137 which extends from an arm connected to an upper surface of the terminal 107c and is received by a third slot 139c arranged between the first slot 139a and the second slot 139b. In practice, only two different forms of plug pins 107 need to be manufactured because the same plug pin 107 with connected male tab 137 may be used for the live teπninal 107b and the neutral terminal 107c by rotating one terminal 180 degrees relative to the other such that the upper and lower surfaces are flipped. An identical arrangement of terminals 107 and male tabs 137 is provided for each of the two plug parts 105a and 105b.

Figure 14 is a perspective view of the back box 103 of the multiplug assembly of the present embodiment with the plug parts 105 removed. Figure 15 shows the back box 103 of the multiplug assembly 101 without a rear face and showing the internal elements of the back box 103. As shown, the back box 103 includes side walls provided in this embodiment with rounded edges, a generally flat upper wall provided with the recessed portion having a plurality of ridges 118 running across the width of the upper surface which further advantageously provide an effective grip area for easier removal of the multiplug assembly 101 from the outlet, and a generally flat reinforced bottom wall. An opening is provided in the bottom wall to allow for a plurality of wires 141, enclosed in the insulating sheath 125 connected to the back box 103, to be inserted into the back box 103 of the multiplug assembly 101.

In this embodiment, the wires 141 includes a single ground wire 141a, two separate live wires 141b and two separate neutral wires 141c, insulated from each other and shielded from inadvertent contact by respective insulating sheathes. As those skilled in the art will appreciate, the size of wire will depend on the loading of the individual power requirements. The ground wire 141a is electrically connected to a common ground buss bar 143a which is arranged to receive the respective male tabs 137 of the two ground

) terminals 107a through the slots 139a provided in the back box 103 of the multiplug assembly 101, as discussed above. The two live wires 141b are electrically connected to respective ones of two live buss bars 143b provided on respective sides of the back box 103 via a respective fuse 123. The two live buss bars 143b are arranged to receive the respective male tabs 137 of the two live terminals 107b through the slots 139b, as

5 discussed above. Similarly, the two neutral wires 141c are electrically connected to respective ones of two neutral buss bars 143 c which are arranged to receive the respective male tabs 137 of the two neutral terminals 107b through the slots 139c, as discussed above.

In this embodiment, the physical dimensions of the plug part 105 are configured so that the buss bars 143 are always covered by the plug part 105. According to the present embodiment, to achieve the coverage and movement to accommodate all standard and typical UK duplex outlets, the plug parts 105 have a width of 50 mm, the slots 139 for access to the buss bars 143 are 22 mm wide and the tabs 137 are 6 mm wide. Of course, those skilled in the art will appreciate that many other suitable dimensions are possible. For example, the plug parts 105 may have dimensions in the range of 25 to 55 mm in width and 25 to 55mm in height. The slots 139 may be between 5 and 30 mm in width. The tabs 137 may be between 1 and 10 mm in width.

As discussed above, in this embodiment, the male tabs 137 are provided in the plug parts 105 and the inter-connecting buss bars 143 are provided in the back box 103 of the multiplug assembly 101. Figure 16 is a close-up sectional view through the multiplug assembly 101 of the present embodiment, illustrating the inter-connection between the male tabs 137 and the buss bars 143, as discussed above. As shown in the close-up view, the male tabs 137 are slidably received in and electrically connected to U-shaped portions of the buss bars 143 which effectively restrict relative sliding movement of the male tabs 137 along the length of the buss bars 143 while remaining in constant electrical interconnection. As those skilled in the art will appreciate, in an alternative embodiment, the male tabs 137 may instead be provided in the back box 103 of the multiplug assembly 101 and the buss bars 143 provided in the plug parts 105. Additionally, it will be appreciated that the illustrated inter-connection is schematic and the shape of the buss bar must be suitable to facilitate a sufficient electrical connection with the male tabs to meet the load requirements.

I As those skilled in the art will appreciate, the distance between the outside of the surface of the plastic moulding of the back box 103 and the live parts of the buss bars 143 could be optimized to enhance the electrical creepage distance. The portions of the tabs 107 that are not inserted into the buss bar 143 can be sleeved with insulated material so that the live parts cannot be accessed if the plug part 105 inadvertently becomes disconnected from the

! back box 103. Furthermore, the electrical creepage and clearance distances may sufficient such that individual slots are not required in the moulding above the buss bars.

Those skilled in the art will appreciate that the plug parts 105 according to the present embodiment are less complex than a typical plug because some of the electrical components (for example, the electrical wiring and/or the fuses) may not provided in the

) plug part 105 but instead within the back box 103. Accordingly, it is simpler to manufacture the plug part 105, for example by using a technique of insert moulding around the pins.

Fourth embodiment

Figure 17, which comprises Figures 17a to 17c, is a perspective view of a i multiplug assembly 151 of a fourth embodiment of the present invention, hi this embodiment, the multiplug assembly 151 is provided with a handle 153 which is pivotally mounted to the back box 153 of the multiplug assembly 151 for movement between a stowed position as shown in Figure 17a and a deployed, grippable position as shown in

Figure 17b. As shown in Figures 17a and 17b, the multiplug assembly is engaged with a

) duplex outlet 111. By pivoting the handle 153 from the stowed position to the grippable position, a user may grasp the handle 153 and easily pull the multiplug assembly 153 to disengage it from the duplex outlet 111 , as shown in Figure 17c.

Additionally, in this embodiment, the ends of the leg portions of the handle 153 are provided with protruding members 161 which are arranged to abut the surface of the 5 duplex outlet 111 when the handle 153 is moved to the grippable position. When the protruding members 161 contact the surface of the duplex outlet 111, the protruding members 161 act to initiate disengagement of the multiplug assembly 151 from the duplex outlet 111 to further advantageously allow for easier disengagement.

Figure 18 is another perspective view of the multiplug assembly of the fourth

) embodiment. As shown in Figures 17 and 18, the plug parts 105a and 105b are also slidably connected to the back box 157 of the multiplug assembly 151 in the same way as described in the third embodiment except that the plug parts are not permanently attached by way of plug straps as previously described. The plug parts 155 may be held permanently attached to the back box 157 by clamps through the back box (not shown for

5 clarity purposes) or by any other suitable clamping means which may be attached to the back box 157 or the plug parts 155 themselves (such that a pulling force is applied to the plug parts rather than the back box).

Additionally, as shown in Figure 18, the handle 153 has a portion overhanging or projecting beyond the back box 157 to enable easy access to the handle 153 when the handle 153 is in the stowed position. Furthermore, the handle 153 is profiled so as to advantageously guide a user to grip the middle portion of the handle 153 so as to cause an even pull on the multiplug assembly 101. Additionally, a support bar (not shown) may be provided to attach the handle 153 to the plug parts 105 such that even if a user were the grip the handle 153 at an off-centre position, the support bar will act to spread the load across both plug parts thereby ensuring that both plug parts disengage from their respective sockets substantially at the same time.

Figures 19, 20 and 21 show an exploded perspective view of the multiplug assembly 151 of the fourth embodiment and show the internal elements of the plug parts 155 and the body 157 of the multiplug assembly. Like components in this embodiment have been given the same reference numerals as their respective counterparts discussed in the third embodiment above and the way in which these components inter-connect and operate is the same as described in the third embodiment.

As illustrated in Figures 20 and 21, in this embodiment, the fuses 123 are located centrally between the plug parts 105a and 105b and the respective electrical components and therefore are accessible via respective fuse covers 121 when the plug parts 105 are positioned furthest apart from each other.

The above embodiments are presented as separate embodiments but those skilled in the art will appreciate that any combination of the plugs and appliances described in the above embodiments and alternatives is possible.

For example, in the third embodiment described above, the multiplug assembly is provided with two plug parts for electrical connection with respective outlets of a duplex outlet. As those skilled in the art will appreciate, as an alternative, the multiplug assembly may be adapted to provide more than two plug parts for electrical connection with respective ones of a plurality of outlets. Additionally, it will be appreciated that different plug parts may be used with the same back box, for example, to provide a variety of plug adapters for use with the same back box.

In the third embodiment and alternatives described above, the back box houses a number of buss bars which receive and electrically couple to plug pins of connected plug parts. As those skilled in the art will appreciate, this is merely one way of providing an electrical coupling between the plug parts and the back box and other ways of providing this electrical coupling are envisaged. For example, the plurality of live, neutral and earth wires may be arranged to be directly coupled to respective terminals of the plug parts. The wires could be attached to the terminals by way of screw attachments (for example as discussed with reference to Figure 4) or could be more permanently attached such as by welding or crimping the wires to the terminals. In this way, the back box is simplified because there is no need for the plurality of buss bars. Furthermore, the multiplug assembly advantageously becomes non-rewireable as discussed above.

In the third embodiment described above, the plug parts have a sufficient thickness providing a sufficient gap to allow the multiplug assembly to accommodate different

I locations of isolation switches of a duplex outlet. As those skilled in the art will appreciate, in some cases, the multiplug assembly may prevent access to the isolation switches, for example if the switches are located centrally on the outlet faceplate. As an alternative, push rods may be provided on the body of the multiplug assembly to provide access to the isolation switches. As yet another alternative, the shape of the body of the

> multiplug assembly may be recessed or otherwise adapted to allow access to the switches.

In the third embodiment described above, the back box is provided with fuse covers which allow access to fuses provided in the back box. As those skilled in the art will appreciate, the fuses may instead be provided in the plug parts themselves. Additionally, those skilled in the art will appreciate that access to the fuses should not be ) allowed when the multiplug assembly is in use. In the third embodiment, the gap of about 10 mm should be sufficient to prevent access via the fuse covers to live parts. Of course, those skilled in the art will appreciate that the gap may be greater than 10mm. In such a case, the fuse cover can be further adapted to prevent access to live parts.

In the third embodiment described above, latches are provided on the plug parts for

5 engagement with ridges provided on the back box. As those skilled in the art will appreciate, the latch mechanism may instead be provided on the plug straps for latching engagement with the back box. Additionally, handle means may be provided on the plug straps to further aid disengagement of the multiplug assembly from the outlet. As yet a further modification, the handles may be designed to provide a dual function of aiding

D disengagement as well as providing latching means arranged to prevent sliding movement of the plug parts relative to the back box. In the third embodiment described above, the two plug parts are slidably positionable independently of each other. As those skilled in the art will appreciate, in an alternative, the multiplug assembly may be arranged to couple slidable adjustment of one plug part in one direction with corresponding slidable adjustment of the other plug part in the opposite direction. In this way, the plug parts will always be positioned around the centre point, hi yet another alternative, the multiplug assembly may be arranged so that one of the plug parts is fixedly attached to the back box and one of the plug parts is slidably attached to the back box. hi such an alternative, adjustment of the spacing between plug parts is achieved by slidable adjustment of the slidable plug part relative to the fixed plug part.

In the third embodiment described above, slots are provided in the back box to receive male tabs attached to the plug pins for electrical coupling with buss bars provided within the back box. As those skilled in the art will appreciate, it is not essential for slots to be provided in the back box and any suitable aperture or apertures may instead be provided in the back box for allowing the tabs to contact the buss bars, provided the plug part prevents access to the live parts of the back box.

Another alternative arrangement is illustrated in Figures 25-28. In this alternative, the male tabs of the plug parts 105 a, 105b are replaced by a rectangular block 160 provided at the end of an arm 161 extending from the face of the plug part 105a, 105 b. The block 160 carries three electrical terminals 162a, 162b, 162c provided respectively along a front face and on opposite distal ends of the block 160, and electrically connected respectively to the ground pin 107a, live pin 107b and neutral pin 107c of the plug parts 105a, 105b. The back box 103 contains a pair of slots 164a, 164b for receiving the blocks 160 of the corresponding plug parts 105a, 105b. To assemble the plug parts 105 onto the back box 103, as shown in Figures 25a to 25c, the block 160 is inserted into the corresponding slot 164, and the plug part 105 a, 105b is then rotated clockwise through approximately 90° to the position shown in Figure 25c. In this position, as shown in Figure 26, the terminals 162a, 162b, 162c each contact a respective buss bar 143 a, 14b, 14c provided within the back box 103, and the plug part 105a, 105b is locked in position onto the back box 103.

Figure 28 shows in cross section a plug part 105 locked in position on the back box 103, by the engagement of the block 160 between the buss bar 143 and the sides of the slot 164, which may have inwardly projecting portions. In this way, the need for the back straps 135 is removed, thereby providing a simpler and more attractive design.

The plug parts 105a, 105b may be slidable along the slots 164a, 164b, in the position shown in Figure 25b, prior to rotation into the locked position of Figure 25 c, so that the ' spacing between the plug parts 105 a, 105b can be adjusted. Alternatively, a single slot may be provided along the length of the back box 103 for receiving the elongated blocks 160 of one or more plug parts at variable positions along the single slot.

The plug parts 105a, 105b may be unlocked for adjustment by rotating anticlockwise, to return from the position shown in Figure 25c to that shown in Figure 25b. The rotation ) may be sufficient to unlock the plug part 105a, 105b for adjustment, without disengaging the plug part 105a, 105b from the back box 103; the amount of rotation is substantially less than 90°, such as approximately 10°.

As an alternative, the plug parts may be unlocked for adjustment by another mechanism, such as a locking mechanism that is released by a button or lever arranged in a user- 5 accessible part of the plug parts 105a, 105b.

It is not essential that both plug parts 105a, 105b should be lockable in position relative to the back box 103; only one or none of the plug parts need be lockable, as discussed above.

The blocks 160a, 160b may be inserted into the slots 164a, 164b during manufacture in such a way that the plug parts 105 a, 105b cannot be subsequently disengaged from the

) back box 103 by the user, but the user may adjust the positions of the plug parts 105 a, 105b along the slot(s) 164. Alternatively, the blocks 160a, 160b may be located in the back box 103 during assembly thereof, so that there is no need to insert the blocks 160a, 160b into the slot(s) 164 or to rotate the plug parts 105 so as to bring the electrical terminals 162a, 162b, 162c into contact with the buss bars 143a, 143b, 143c. The slots 164 may

5 therefore be narrower, dictated by the width of the arms 161 rather than that of the blocks 160.

Alternatively, the plug parts 105 a, 105b may be locked into position on the back box 103 during manufacture, such that they cannot be adjusted by the user; this allows the multiplug assembly 101 to be constructed with plug parts 105a, 105b suitable for the intended market, while using the same back box 103 for each market. One or more of the terminals 162a, 162b, 162c may be resiliency attached to the block 160, for example by way of a leaf spring or an internal spring, which allows the electrical terminals 162a, 162b, 162c to make a reliable electrical connection with the respective buss bars when the former are rotated into position. Figures 27a and 27b show one possible configuration using leaf springs, in a non-compressed and a compressed state respectively. Figure 28 shows an alternative configuration, in which the terminals 162b, 162c are resiliency biased outwardly by coil springs 165a, 165b within the block 160.

Additionally, one or more flaps or other closures may be provided for the or each slot 164 of the back box 103, so as to prevent or hinder access to the internal components of the back box 103 other than by the blocks 160. In embodiments having a single slot 164 for receiving multiple plug parts 105a, 105b, a cover may be fitted to cover an exposed part of the slot 164 extending between the plug parts 105a, 105b; the cover may be retained within the slot 164.

In the embodiment of Figures 25-28, the block 160 functions both as a support for the terminals 162a,b,c and to lock the plug part 105 in position, but alternatively the block or a similar arrangement may be used for only one of these functions, and an alternative arrangement may be used for the other function.

In the third embodiment described above, the plug parts are designed for use in the UK and to supply two separate power supplies from the multiplug assembly. Accordingly, five separate wires are provided within the insulating sheath connected to the back box. As those skilled in the art will appreciate, in an alternative, it may not be necessary to provide an earth wire, for example for use with appliances not requiring an earth terminal. Furthermore, it may be possible to provide a combined higher power supply from the multiplug assembly. In such a case, a shared buss bar may be provided for the live terminals and connected to a single output live wire. Similarly, a shared buss bar may be provided for the neutral terminals and connected to a single output neutral wire. Accordingly, in some cases, it may be possible to provide two output wires from the back box, a single live output wire and a single neutral wire.

As those skilled in the art will appreciate, plug and socket design will vary depending on

) the country and location of intended use. For example, power outlet or socket faceplates in

Europe and North America typically provide different numbers and arrangements of sockets. Consequently, the shapes and sizes of typical plug housings vary significantly from country to country. Examples of plugs suitable for use in the UK, Europe, North America and Australia are illustrated in Figures 29a, 29b, 29c and 29d respectively; these may comply with the plug standards for those countries, or may have features that differ from or are additional to those standards: for example the plug mounting parts may be circular instead of rectangular; the plug parts may be rotatable to facilitate angled or perpendicular sockets; or the plug parts may be moveable towards or away from each other to match specific socket types. As those skilled in the art will appreciate, the multiplug assembly of the present invention may accommodate any shape and size of plug part. It may be necessary to accommodate for variations of the plug parts such as different shapes, possibly to accommodate recessed sockets (round plug heads are sometimes used), variable widths, varying clockwise or counter-clockwise angles, or varying angles of the plug faces (angled socket face plates are sometimes used). For example, it may be necessary for a round plug part to incorporate a rectangular portion to cover or incorporate the buss bars. Furthermore, it may be possible to utilise travel adapters between the plug parts and the outlets for use in different countries or to provide an adapter plug part suitable for receiving plugs of different types as used in different countries. As yet another alternative, the plug parts may be designed to rotate to accommodate variations in the socket faceplate. Figure 23, which comprises Figures 23a to 23c,

) illustrates one example alternative plug part 105 which comprises three separate components: a back part 190 which plugs into the back box; a front rotatable part 191 that rotates about the back part 190 by 90 degrees; and a moulding 192 to clamp the back part 190 and the front rotatable part 191 to the back box. hi this way, the plug part may be inserted into the back box of the third embodiment in the

J same way as discussed above. Figure 24, which comprises Figures 24a and 24b, illustrates another example alternative arrangement where the plug part 105 has a male moulding 195 with three annular conductors 196a, 196b, 196c, each connected to a pin 107a, 107b, 107c on the plug part 105. The circular bands are arranged so as to interface with cooperating buss bars in the back box 103 to enable electrical coupling between the rotatable plug part

3 and the back box. hi a further alternative, the circular bands could be simplified if only 90 degree movement is required, in which case two of the bands could be less than 180 degrees (e.g. 120 degrees) around the male part of the plug and the third connector could be situated along the central plane of the male part between the two circular parts.

In the fourth embodiment described above, a handle is provided on a dual plug assembly to advantageously aid disengagement of the plug assembly from a duplex socket. As those skilled in the art will appreciate, a typical single plug may be adapted to incorporate such a handle to provide the described advantage.

In the embodiments described above, the multiplug 101 is directly connected by a power lead to the appliance; in other words, the multiplug 101 is connected to a captive lead. For example in the third embodiment illustrated in Figure 15, the five separate wires are i brought together in the back box 103 and provided within the single power lead extending from the back box 103. In an alternative illustrated in Figure 30, the power lead is instead provided with a five pin connector 170 at the end of the power lead, for connection to a complementary connector 171 of another power lead connected to the appliance. In another alternative illustrated in Figure 31, the five-pin connector 170 is connected directly i to a power inlet 172 of an appliance. In this way, the connector 170 may be threaded through an access hole to an appliance, thus facilitating connection of the appliance. It is not essential that the connector 170 have five pins; for example, four pins would be sufficient if no earth connection is required, but six pins may be required if separate earth connections are provided for each plug. The connector 170 may be used in the

) embodiment of Figures 6a and 6b, in which only three pins are required, or only two pins if there is no requirement for an earth connection.

The connectors 170, 171 may comprise pins and complementary sockets, or may alternatively comprise circular connectors such as used in 360° cordless connectors or coaxial connectors. The connectors 170, 171 may not be compatible with other, standard connectors, to avoid inadvertent connection to inappropriate electrical equipment. Alternatively, the connector 170 may be compatible with a standard, high power connector, such as those used in caravan sites or marinas, to allow a caravan or boat to be connected to multiple domestic power sockets. There may be provided a locking mechanism for locking the connector to the complementary connector 171 or the inlet 172, to prevent accidental disconnection of the power connector 170. In a further embodiment, illustrated in Figure 32a, the connector 170 comprises a plurality of extension sockets 175a, 175b, preferably arranged to receive another multiplug; in other words, a multiplug extension lead is provided, comprising the multiplug 101, power lead including sheath 125, and the connector 170. Each extension socket 175a, 175b may be connected to a corresponding plug part 105a, 105b within the multiplug 101. Hence, this embodiment differs from a standard extension lead in that multiple extension sockets do not draw power from a single plug, thereby increasing the total power rating of the extension lead.

The embodiment of Figure 32a can be used as an extension lead for standard single plugs. Alternatively, the extension sockets 175a, 175b may be arranged to receive only a multiplug 101 and not to receive a standard single plug. In the variant of Figure 32b, each extension socket 175a, 175b is arranged in a recess shaped to receive the plug part 105a, 105b of the multiplug 101, which is shaped differently from a standard plug. In the variant of Figure 32b, each extension socket 175a, 175b includes a protruding portion arranged to be received within a complementary recess within the plug part 105a, 105b, which is not present in standard single plugs. Alternatively, a magnetically operated relay and corresponding magnet could be provided in the higher powered extension sockets 175a, 175b, and the multiplug 101, or vice versa, such that an electrical connection can only be established between the extension sockets 175a, 175b and the multiplug 101. In a further embodiment, illustrated with reference to Figures 33a, the duplex power outlet 111 has a face plate including a recess 80a, 80b around each power socket 109a, 109b, the recesses being dissimilar between the two power sockets 109a, 109b. As shown in Figure 33b, the plug parts 105a, 105b of the multiplug 101 have complementary projections 82a, 82b that fit within the corresponding recesses 80a, 80b when the multiplug 101 is correctly connected to the power outlet 111 such that both plug parts 105a, 105b are connected to the respective power sockets 109a, 109b. The projections 82a, 82b are sufficiently long to prevent connection such that only one plug part 105 is connected, for example where plug part 105a is connected to power socket 109b, as illustrated in Figure 33c; this is possible for example where the power outlet 111 projects from its support surface, such that the plug part 105b is left unconnected in a position beyond the power outlet 111. In embodiments in which the plug parts 105a, 105b are connected to a single load, this arrangement avoids a situation in which the disconnected plug part 105 may become live. However, the recesses 80a, 80b do not prevent standard plugs from being connected to the power outlet 111. Additionally, interdependent control means as described above may be provided to ensure that an individual plug part cannot be overloaded if power is disconnected from the other circuit.

For a UK plug, the projections 82a, 82b should project by approximately 6 mm or more from the plug parts 105, and preferably by more than 7 mm to prevent connection if the plug part is rotated about an axis parallel to the faceplate. Alternatively, multiple spaced- apart projections 82 may be provided for each plug part 105, to prevent such rocking; in that case, the projections 82 need only project by approximately 6 mm or greater for a UK plug. Alternatively, a single projection 82 may be provided for each plug part 105, the projection 82 extending in one or both dimensions parallel to the face of the plug part 105; for example, the projection 82 may be T-shaped in cross-section. The projections may need to be longer in order to meet standards approval requirements; for example, the projections 82 would need to be at least 14 mm long to meet UK standards. The projections 82 and recesses 80 may act to inhibit accidental removal of the multiplug 101 from the power outlet 111. For example, the projections 82 may snap fit into the recesses 80, or there may be a magnetic coupling between the projections 82 and the recesses when fitted together.

The faceplate including the recesses 80a, 80b may be provided as a replacement for a standard faceplate, for example using similar screw fittings. Alternatively, the faceplate including the recesses 80a, 80b may be provided as an adapter for fitting onto a standard duplex power outlet, to avoid the need to remove the standard face plate. As an alternative to the projections 82a, 82b and recesses 80a, 80b, other mechanical arrangements may be provided to achieve the same effect. For example, Figure 33d shows projections 82a, 82b and corresponding recesses 80a, 80b provided adjacent the live and neutral pins 107b, 107c, arranged laterally outward of the pins of the plug part 105b and laterally inward of the pins of the plug part 105a. As another example, Figure 33e shows projections 82a, 82b and corresponding recesses 80a, 80b provided between the live and neutral pins 107b, 107c, extending horizontally in the plug part 105b and vertically in the plug part 105a. A similar arrangement may be used in the extension sockets 175a₅ 175b of the extension leads shown in Figures 32b and 32c. In the embodiments described above, the plug parts are described in accordance with a typical domestic plug found in the UK, having an earth pin, a live pin and a neutral pin. As those skilled in the art will appreciate, the present invention is also applicable to different types of plugs which do not necessarily have these electrical terminals. For

> example, in an alternative, the multiplug may be adapted as a 3-phase multiplug having four or more electrical pins, for example one earth pin and three respective phase pins. In such an alternative, the back box of the third embodiment and alternatives for example would also be adapted to include four buss bars corresponding to the four pins of each 3- phase plug part. As is known in the art, more than four terminals may be required for a 3-

) phase plug and socket, and the number of pins and buss bars may be selected accordingly. Embodiments of the invention may alternatively be adapted for other numbers of phases, such as 2-phase or 6-phase, or for split phase power supplies as used for example in the USA and Canada. The above embodiments illustrate, but do not limit, the present invention. Alternative

> embodiments which may occur to the skilled reader on reading the above description may also fall within the scope of the invention. Additionally, although the above embodiments are presented as separate embodiments, those skilled in the art will appreciate that combinations of aspects of each embodiment and the alternatives described above is possible.

)

Claims

CLAIMS:

1. A multiple plug connector for simultaneous connection to a plurality of electrical power sockets, the multiple connector comprising an integrated plurality of plug portions for connection to the respective plurality of sockets, each of the plug portions comprising a plurality of terminals.

2. The multiple plug connector of claim 1, wherein at least some corresponding terminals of each of the plug portions are connected to a common electrical connector in a power lead.

3. The multiple plug connector of claim 2, wherein said corresponding terminals comprise earth terminals.

4. The multiple plug connector of claim 2, wherein said corresponding terminals comprise live terminals.

5. The multiple plug connector of claim 2, wherein said corresponding terminals comprise neutral terminals.

6. The multiple plug connector of claim 1, wherein at least some corresponding terminals of each of the plug portions are connected to respective different wires in a power lead.

7. The multiple plug connector of claim 6, wherein the respective different wires are provided in respective different conduits of the power lead.

8. The multiple plug connector of claim 6, wherein the respective different wires are provided in the same conduit of the power lead.

9. The multiple plug connector of any preceding claim, wherein at least one of the plug portions is movable relative to another one of the plug portions to vary the spacing therebetween.

10. The multiple plug connector of claim 9, wherein said at least one of the plug portions is slidably mounted with respect to said other one of the plug portions.

11. The multiple plug connector of claim 9 or 10, wherein at least two of the plug portions are coupled together so that movement of one of the plug portions in one direction causes movement of the other plug portion in the opposite direction.

12. The multiple plug connector of any one of claims 9 to 11, wherein the power lead is fixed with respect to one of the plug portions.

13. The multiple plug connector of any preceding claim, wherein the plug portions are mounted on a common support.

> 14. The multiple plug connector of claim 13, wherein the plug portions project from the common support so as provide a gap between the common support and the power sockets when the multiple plug connector is plugged into the power sockets.

15. The multiple plug connector of claim 14, wherein said gap is sufficient to accommodate an isolation switch of the socket.

) 16. The multiple plug connector of any one of claims 13 to 15, wherein the common support comprises a plurality of buss bars for electrical connection to the respective plurality of terminals of said at least one plug portion.

17. The multiple plug connector of any one of claims 13 to 16, wherein said at least one plug portion is slidably mounted in a slot in the common support.

) 18. The multiple plug connector of claim 17, wherein said at least one plug portion includes an elongate member for insertion or inserted into said slot, the elongate member providing an electrical connection between the plug portion and the common support.

19. The multiple plug connector of claim 17 or 18, wherein the plurality of plug portions 3 are slidably mounted in a common said slot.

20. The multiple plug connector of claim 17 or 18, wherein the plurality of plug portions are slidably mounted in a respective plurality of said slots.

21. The multiple plug connector of any one of claims 17 to 20, wherein the or each slidably mounted plug portion is releasably securable to the common support.

22. The multiple plug connector of claim 21, wherein the or each slidably mounted plug portion is resiliently securable to the common support.

23. The multiple plug connector of claim 21, wherein the or each slidably mounted plug portion is securable to the common support with a small degree of play.

24. The multiple plug connector of claim 21, wherein the or each slidably mounted plug portion is securable to the common support by rotation of the plug portion with respect to the common support.

25. The multiple plug connector of claim 24 when dependent on claim 18, wherein rotation of the plug portion brings the elongate member into electrical connection with the common support.

26. The multiple plug connector of any preceding claim, including means for indicating the operational status of each of the plug portions.

27. The multiple plug connector of any preceding claim, wherein a handle is connected to the common support for assisting removal of the multiple plug connector from the plurality of sockets.

28. The multiple plug connector of claim 27, wherein the handle is movable between a deployed position and a stowed position.

29. The multiple plug connector of claim 28, wherein the handle is coupled to means for pushing the multiple plug connector away from the sockets when the handle is moved to its deployed position.

30. The multiple plug connector of any preceding claim, wherein the plug portions are coplanar.

31. The multiple plug connector of any preceding claim, arranged to prevent electrical connection of one of the plug portions to an electrical load when another one of the plug portions is not electrically connected to the electrical load.

32. The multiple plug connector of claim 31, including a switch activated by the supply of power from one of the plug portions to enable the supply of power from another one of the plug portions.

33. The multiple plug connector of any preceding claim, arranged to prevent electrical connection of one of the plug portions to the corresponding socket when another one of the plug portions is not electrically connected to the corresponding socket.

34. The multiple plug connector of claim 33, wherein each of said plug portions includes a feature arranged to interact with a feature of the corresponding socket and not to interact with a feature of a non-corresponding socket.

35. The multiple plug connector of claim 34, wherein the feature of each of the plug ϊ portions comprises one or more projections and the feature of the corresponding socket comprises one or more recesses within which said one or more projections fit.

36. The multiple plug connector of claim 35, wherein said projection or projections arranged to prevent connection of the plug portion to a socket not having a corresponding recess.

) 37. The multiple plug connector of claim 36 wherein said projection or projections prevents rocking of said plug portion such as to allow connection to said socket not having a corresponding recess.

38. The multiple plug connector of any one of claims 34 to 35, wherein said interaction inhibits removal of the plug portion from the corresponding socket.

5 39. A socket or socket part having a feature according to any one of claims 34 to 38.

40. An extension lead comprising the multiple plug connector of any one of claims 1 to 38, an extension connector, and a power lead connected between the multiple plug connector and the extension connector.

41. The extension lead of claim 40, wherein the extension connector comprises a plurality ) of terminals connected respectively to a plurality of wires within the lead.

42. The extension lead of claim 41, when the extension connector comprises a single connector.

43. The extension lead of claim 40 or 41, where the extension connector comprises a plurality of extension sockets electrically connected respectively to said plurality of

5 plug portions.

44. The extension lead of claim 43, wherein the plurality of extension sockets are arranged for connection with a further multiple plug connector according to any one of claims 1 to 38.

45. The extension lead of claim 44, wherein the extension sockets are arranged to prevent connection with a standard single plug.

46. An electrical appliance connectable or connected to the extension lead of any one of claims 40 to 45.

47. An electrical appliance connectable or connected to the multiple plug connector of any one of claims 1 to 38.

48. The electrical appliance of claim 47, comprising a plurality of electrical loads each connected or connectable to a respective one of the plurality of plug portions.

49. The electrical appliance of claim 48, comprising an integrated plurality of appliances each connected or connectable to a respective one of the plurality of plug portions.

50. The electrical appliance of claim 49, wherein at least one of the integrated plurality of appliances is separable from another one of the integrated plurality of appliances.

51. The electrical appliance of claim 48, comprising a liquid heating appliance comprising a plurality of heaters each connected or connectable to a respective one of the plurality of plug portions.

52. The electrical appliance of claim 51, wherein the heaters comprise flow-through liquid heaters.

53. The electrical appliance of claim 52, wherein the flow-through liquid heaters are arranged in series.

54. The electrical appliance of claim 52, wherein the flow-through liquid heaters are arranged in parallel.

55. The electrical appliance of claim 47, comprising an electrical load connected or connectable to said plurality of plug portions.

56. The electrical appliance of claim 55, arranged to prevent electrical connection of one of the plug portions to the electrical load when another one of the plug portions is not electrically connected to the electrical load.

57. The electrical appliance of claim 55 or 56, comprising a liquid heating appliance having a heater connected or connectable to each of said plurality of plug portions.

58. The electrical appliance of claim 57, wherein the heater comprises a flow-through liquid heater.

59. The electrical appliance of claim 51 or 57, wherein the liquid heating appliance comprises a main reservoir portion in which the heaters are arranged to heat liquid within the reservoir, connectable to a cordless base via respective cordless electrical connectors.

60. The electrical appliance of any one of claims 51, 57 or 59, wherein the liquid heating device further comprises at least one switch, thermostat and/or control along with the associated control circuitry.