Field of the invention

The present invention relates to a food processor attachment mechanism. More particularly, it relates to a mechanism for attaching an attachment to a food processor base.

Background

Food processors typically consist of a base unit housing a motor and motor-control means, and attachments that can be attached thereto. These attachments can include containers in which dicing, chopping, mixing and other tools may be located. They may also include blender attachments comprising a jug and rotary knife tool, meat-mincers, juicing attachments (including auger-type juicers and centrifugal-type juicers), pasta-makers, and other tools. For all of these tools, it is important to ensure that the tools are correctly attached before energising the motor to drive the tools within the attachment. This avoids non-optimal results from processing, and potential injury to the user (particularly when the lid is not attached for a bladed attachment).

To achieve this food processors are typically interlocked, such that the motor cannot be energised when the attachment is not properly attached. This is typically achieved by providing a push-rod/microswitch arrangement, where correct attachment of the attachment to the food processor base unit causes a push-rod to actuate a microswitch sending a signal to the motor control means allowing energising of the motor.

As it is difficult/expensive to provide multiple such push-rod/microswitch arrangements, the attachment typically can only be attached to actuate the microswitch at one orientation. However, the user may forget what the correct orientation is, and will often find it hard to locate the correct orientation. Whilst visual indicia may be provided to remind the user of what the correct orientation is, the user may not see them due to impaired sight, or they may become worn away. Another issue found in the food processor field is that attachments typically lock to base units by rotating the attachment either clockwise or anti-clockwise such that a protrusion on one of the attachment and the base is latched within a recess of the other. However, the user may well forget what the correct direction of rotation is to achieve locking as this varies from brand to brand. Additionally, as these attachment mechanisms typically only latch in a single direction of rotation, they are not equally easy for left and right-handed people to use.

The present invention aims to at least partially ameliorate the above-described problems of the prior art.

Summary of the Invention

In an aspect of the invention, there is described a food processing arrangement comprising a base unit and a food processing attachment wherein: one of the base unit and the attachment comprises at least one slope; and the other of the base unit and the attachment comprises at least one guiding element configured in use to move along said at least one slope towards an operating position. The guiding elements being arranged to move along the slope towards an operating position improves the user experience of placing the attachment on the base at a desired position.

Preferably, the arrangement further comprises at least one latch arranged to releasably attach the base unit and an attachment when the or each guiding element is in the operating position. Optionally, the arrangement comprises a plurality of latches.

Optionally, the latch is arranged at, or near, the base of a corresponding slope.

Optionally, the latch is arranged along a corresponding slope.

Preferably, the latch comprises a bi-directional latch.

Preferably, the latch is arranged to prevent relative movement of the base unit and the attachment. Optionally, said latch is arranged to prevent relative movement of the base unit and the attachment in an axial direction. Optionally, said latch is arranged to prevent relative movement of the base unit and the attachment in a radial direction.

Preferably, the or each latch is releasable in dependence on a user input, preferably the depression of a button.

Preferably, the or each latch is arranged between two opposing slopes.

Preferably, the or each slope forms a part of at least one bi-directional ramp, with the or each ramp comprising two slopes facing in opposite directions. Preferably, the number of ramps is three or more. Preferably, the number of ramps is three or four.

Preferably, the or each guiding element comprises runners arranged to run over the slopes. Preferably, the runners comprise sliding runners.

Optionally, the or each guiding element comprises wheels or rollers.

Preferably, the or each guiding element is arranged to move along the or each slope under the influence of gravity.

Preferably, a slope-angle of the or each slope and a co-efficient of friction between the or each guiding element and said slope is configured such that said guiding element moves under the influence of gravity alone along said slope towards the or each latch.

Optionally, a slope angle of the or each slope is greater than 25°, is greater than 30°, is greater than 35°, and/or is approximately 40°.

Preferably, the arrangement comprises a plurality of slopes and a plurality of guiding elements. Preferably, the slopes and the guiding elements are arranged so that in use each guiding element moves along a different slope.

Preferably, the or each slope and the or each guiding element is arranged so that in use a guiding element either comes into contact with said slope or is located at said operating position irrespective of an initial orientation of the base unit and the attachment.

Preferably, one of the attachment and the base unit comprises an annular rim, and the other of the attachment and the base unit comprises an annular protrusion configured to be received within the rim. Optionally, one of the attachment and the base unit comprises a cylindrical rim, and the other of the attachment and the base unit comprises an cylindrical protrusion configured to be received within the rim

Preferably, the or each slope extends along the rim and/or the protrusion.

Preferably, the or each guiding element extends along the rim and/or the protrusion.

Preferably, the or each slope extends along one of the rim and the protrusion and the or each guiding element extends along the other of the rim and the protrusion.

Preferably, the or each guiding element is provided on the attachment, and the or each slope is provided on the base unit.

Preferably, the base-unit comprises a motor and/or heating element.

Preferably, the operating position corresponds to a position where an interlock switch of the base unit is configured to be actuated by the attachment. Preferably, the motor and/or heating element can be activated in said operating position.

Preferably, a latching position of the or each latch corresponds to a position where an interlock switch of the base unit is configured to be actuated by the attachment. Preferably, the motor and/or heating element can be activated in said latching position.

Optionally, a slope angle of the or each slope varies along the length of said slope. Preferably, the slope angle decreases near a/the operating position and/or a/the latch.

Optionally, the or each slope comprises two sub-slopes, with each sub slope having a constant slope angle, wherein the slope angle of the sub-slopes differs. Optionally the or each slope comprises: a first part with a first slope angle and a first coefficient of friction, the first slope angle and the first coefficient of friction being such that, in use, a corresponding guiding element accelerates along the first part under the force of gravity; and a second part with a second slope angle and a second coefficient of friction, the second slope angle and the second coefficient of friction being such that the corresponding guiding element decelerates along the second part under the force of gravity.

Preferably, the or each slope and/or the or each guiding element comprises a low friction material, preferably a low friction coating, more preferably a Teflon coating.

Preferably, the attachment comprises a container. Preferably, the container is arranged to be enclosed by a removable lid, wherein one of the container and the lid comprises at least one further slope, and the other of the container and the lid comprises at least one further guiding element configured to move along said at least one further slope towards a further operating position. Preferably, the attachment is configured to actuate a/the interlock switch when the further guiding element is at the further operating position..

Preferably, the attachment is configured to actuate the interlock switch when the lid is correctly attached to the container.

Optionally, the number of slopes is two or more. Optionally, the number of slopes is six or eight.

In another aspect of the invention, there is disclosed a base unit as aforesaid. The base unit may comprise any of the aforesaid preferably features.

In another aspect of the invention, there is disclosed an attachment as aforesaid. The attachment may comprise any of the aforesaid preferably features.

In another aspect of the invention, there is disclosed a base unit for attaching to an attachment comprising at least one guiding element, the base unit comprising at least one slope; wherein the base unit is arranged to interact with the attachment such that, in use, said at least one guiding element of the attachment moves along said at least one slope towards an operating position.

In another aspect of the invention, there is disclosed a base unit for attaching to an attachment comprising at least one guiding element, the base unit comprising at least one slope; wherein the base unit is arranged to interact with the attachment such that, in use, said at least one guiding element of the attachment moves along said at least one slope towards an operating position

In an aspect of the invention, a food processing arrangement is disclosed comprising a base unit, and a food processing attachment configured to be releasably attachable to the base unit, wherein one of the base unit and the attachment comprises one or more bidirectional ramps each having two slopes facing in opposite directions, and the other of the base unit and the attachment comprises one or more runners configured in use to run over the slopes of the one or more bi-directional ramps to one or more bi-directional latches each located between opposing slopes of the one or more bi-directional ramps such that the attachment and base unit are latched together by the bi-directional latches.

This is advantageous as the bi-directional ramps guide the user to move the attachment toward the latches and thus towards the locking position. Additionally, as the latches and ramps are bi-directional the user experience is the same for both right and left-handed people.

Preferably wherein the one or more runners are sliding runners, and a slope-angle of the one or more bi-directional ramps and a co-efficient of friction between the sliding runners and the one or more bi-directional ramps is configured such that the sliding runners can slide under the influence of gravity alone down the slopes of the one or more bi-directional ramps towards the one or more bi-directional latches. This is advantageous as it can allow the attachment to attach under the influence of gravity, without user interaction beyond placing the attachment on the base at any orientation.

Preferably the one or more runners are wheels or rollers. This may lower the friction involved in the runners sliding over the slopes.

Optionally one of the attachment and the base unit comprises a cylindrical rim, and the other of the attachment and the base unit comprises a cylindrical protrusion configured to be received within the cylindrical rim. This can help retain the base and attachment together and/or concentrically.

In an optional configuration, the one or more bi-directional ramps and/or the one or more runners extend along the rim and/or cylindrical protrusion. This can give a compact arrangement.

In a preferable arrangement, the runners are provided on the attachment, and the bidirectional ramps are provided on the base unit. This can give greater efficiency.

Preferably, a latching position of the one or more bi-directional latches corresponds to a position where an interlock switch of the base unit is configured to be actuated by the attachment, and the base-unit is configured to permit the energising of a motor and/or heating element associated with the arrangement for carrying out food processing operations on food contained within the arrangement responsive to actuation of the interlock switch. This can improve safety of the appliance.

In a preferable alternative, a slope angle of the one or more bi-directional ramps varies along the length of each bi-directional ramp. This can permit the rotation of the attachment to decelerate and prevent excessive acceleration.

Preferably the attachment is made of dishwasher-safe material. This can allow safe cleaning using a dishwasher.

Preferably the arrangement does not contain lubricating oils. This can allow cleaning and prevent contamination due to leakage.

Preferably the attachment comprises a lid and the base-unit comprises a container to which the lid is removably attachable. This can provide advantageous lid attachment. Optionally the attachment comprises a container enclosed by a removable lid, and one of the container and the lid comprises one or more further bi-directional ramps each comprising two further opposing slopes, and the other of the container and the lid comprises one or more further runners configured to run along the further slopes towards one or more further bi-directional latches for latching the lid to the container. In this way both advantageous lid-attachment and container attachment are achieved.

Optionally the attachment is configured to actuate the interlock switch when the lid is correctly attached to the container. In this way safety may be improved.

The arrangement of any preceding claim, wherein the number of ramps is three or more, and preferably three or four. These numbers are potentially stable and efficient.

A food processing appliance is disclosed comprising the food processing arrangement.

The invention also encompasses a kit of parts for constructing any of the apparatuses or apparatus elements herein described.

Any apparatus feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure, such as a suitably programmed processor and associated memory.

Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa. Furthermore, any, some and/or all features in one aspect can be applied to any, some and/or all features in any other aspect, in any appropriate combination.

It should also be appreciated that particular combinations of the various features described and defined in any aspects of the invention can be implemented and/or supplied and/or used independently. In this specification the word 'or' can be interpreted in the exclusive or inclusive sense unless stated otherwise.

Furthermore, features implemented in hardware may generally be implemented in software, and vice versa. Any reference to software and hardware features herein should be construed accordingly.

Whilst the invention has been described in the field of domestic food processing and preparation machines, it can also be implemented in any field of use where efficient, effective and convenient preparation and/or processing of material is desired, either on an industrial scale and/or in small amounts. The field of use includes the preparation and/or processing of: chemicals; pharmaceuticals; paints; building materials; clothing materials; agricultural and/or veterinary feeds and/or treatments, including fertilisers, grain and other agricultural and/or veterinary products; oils; fuels; dyes; cosmetics; plastics; tars; finishes; waxes; varnishes; beverages; medical and/or biological research materials; solders; alloys; effluent; and/or other substances, and any reference to “food” herein may be replaced by such working mediums.

The invention described here may be used in any kitchen appliance and/or as a standalone device. This includes any domestic food-processing and/or preparation machine, including both top-driven machines (e.g. stand-mixers) and bottom-driven machines (e.g. blenders). It may be implemented in heated and/or cooled machines. It may be used in a machine that is built-in to a work-top or work surface, or in a stand-alone device. The invention can also be provided as a stand-alone device.

Brief Description of Drawings

One or more aspects will now be described, by way of example only and with reference to the accompanying drawings having like-reference numerals, in which:

Fig. 1 shows a perspective drawing of a food processor arrangement according to an embodiment of the invention; Fig. 2 shows a partially exploded perspective drawing of the food processor arrangement of Fig.1 ;

Fig. 3 shows a perspective drawing of the attachment of Fig. 1 in an inverted orientation;

Fig. 4 shows a perspective, close-up drawing of the latching arrangement of Fig. 1 ;

Fig. 5 shows a perspective drawing of the base unit of Fig. 1 ;

Fig. 6 shows a force diagram for the runners and ramps of Fig. 1 ; and

Fig. 7 is a close-up drawing showing the lid and attachment of Fig. 1 .

Specific Description

Figures 1 - 5 show a food processor attachment arrangement 100 according to an illustrative, exemplary embodiment of the invention. The arrangement 100 has an attachment 200 having an open upper end 201 which is closed by a lid 300. The lid 300 has a feed-tube 301 , preferably dimensioned so as to prevent the passage of a human hand, through which ingredients can be inserted for processing by the attachment 200. The attachment 200 is releasably attachable to a base 400. The base 400 includes a motor, power supply (internal or external) and motor-control module (not shown) with a processor, memory, and data transmission means capable of receiving and carrying out instructions for controlling the motor.

Attachment 200 connects to the base 400 by the user locating the attachment 200 on the base 400 such that the base rim 205 seen in Fig. 3 is concentric with a cylindrical protrusion 404 of the base 400. Depending on the angle at which the attachment 200 is located on the base 400, it will then be guided by ramps 402 to rotate either clockwise or anticlockwise, with low-friction runners 203 extending from the bottom of the attachment sliding down the ramps 402 under the influence of gravity. The user, with their hand on the handle 202 of the attachment 200, will thus been guided to rotate the attachment 200 (or allow its rotation under the influence of gravity) towards a locking angle where the spring- loaded bi-directional latches 401 (best shown in fig. 4) engage with the bi-directional latching recesses 206. Once at the locking angle, the attachment 200 may actuate an interlock (not shown) on the base 400 indicating that the attachment 200 is properly attached. For example, the interlock may be a micro-switch on the base 400 that is actuated by a protrusion on the attachment 200, or it may be a reed-switch on the base 400 that is actuated by a magnet on the attachment 200, or it may be an RFID or NFC tag on the attachment 200 that is detected by an RFID/NFC transmitter/receiver on the base 400. Responsive to detecting that the interlock has been actuated, the base 400 may permit activation of its motor for driving a tool within the attachment, and/or may permit the energising of a heating element of the arrangement 100 that may be located within either the lid 300, the attachment 200, or the base 400, for heating the contents of the attachment 200.

While Figures 1 - 5 show an embodiment comprising latches 401 and latching recesses 206, more generally there is disclosed an arrangement comprising at least one slope (e.g. a slope of the ramps 402) and at least one guiding element (e.g. the runners 203), where the guiding element is arranged to move along the slope towards an operating position. In the embodiment of Figures 1 , 2, and 3 the operating position is a position in which the latches 401 are received by the latching recesses 206; in other embodiments, the operating position may comprise a valley between two slopes where the guiding elements are held in place in the operating position by the slopes of the valley.

Latches 401 as described herein may comprise clips, clasps, springs, or any other securing structure. The latches 401 are arranged to prevent or restrict one or more of: relative rotation between the base 400 and the attachment 200; relative radial movement between the base 400 and the attachment 200; and relative axial movement between the base 400 and the attachment 200.

As can be seen in Figs. 2 and 4, the ramps 402 extend along the periphery of the cylindrical protrusion 404 and as such are supported by it. Whilst three ramps 402 are shown, the number of ramps 402 may be different to this, including only having a single ramp 402 extending about the entirety of the cylindrical protrusion except at the locking position, two ramps, or four or more ramps. However, a configuration of three or four ramps 402 is preferred as this is more stable than a one- or two-ramp configuration and also more efficient than a five- or more ramp configuration. Each of the ramps 402 is bi-directional, meaning that they rise to an apex and form slopes on either side of the apex. Where a single ramp 402 is used, this rises to an apex and has two slopes either side of the apex inclined towards the correct locking position. Where more than one ramp 402 is used, multiple bi-directional latches may be provided between neighbouring ramps 402.

The latches 401 may retain the recesses both axially (e.g. to prevent removal of the attachment 200 vertically) and rotationally (e.g., to prevent rotation of the attachment 200 away from the locking angle). Alternatively or additionally, rotation of the attachment 200 into the locking position may cause the tabs 207 provided extending inwardly from the base rim 205 to latch beneath retaining elements 405 provided extending radially outwardly on the cylindrical protrusion, thus retaining the attachment 200 axially.

To disengage the latches 401 from the recesses 206, the user depresses button 208. Button 208 is linked to pushrods (not shown) extending through column 209 to the recesses 206. When pushed downwards, the pushrods depress the latches 402 allowing the removal of the attachment 200 from the locking position. Column 209 protects the pushrods and supports the handle 202.

To ensure easy mating between the drive shaft of the tool within the attachment 204 and the drive outlet 403 of the base 400, such that the tool 204 can be driven to rotate by the motor of the base 400 through the drive outlet 403, the tines of each 204a, 403a are preferably sloped/rounded. This sloping/rounding ensures that when they are brought together at a misaligned angle, they slide against each other towards alignment and correct mating.

The slope of the ramps 402 should be at least sufficient to create sufficient gravitational force to guide the user to rotate the attachment 200 in the correct direction to lock it by significantly biasing rotation of the attachment 200 in that direction. More preferably, as shown in the highly simplified diagram of Fig. 6, the static force of friction parallel to the slope (F) between the runners 203 and the ramps 402 acting to keep the runners 203 stationary on the ramps 402, the angle (0) of the slope of the ramps 402, and the typical mass (M) of the attachment 200 during use (and more preferably the dry-weight of the attachment with no additional components or contents), is determined such that the force of gravity (Mg) acting on the attachment 200 is sufficient to overcome the maximum static friction force (F _M ax) between the runners 203 and the ramps 402 when the attachment 200 is oriented such that the runners 203 are located on the ramps 402. This ensures that the attachment 200 self-rotates to the locking angle under the influence of gravity with no further user interaction.

For example, the runners 203 may be steel, and the ramps 402 may also be steel meaning that the static coefficient of friction (p _s ) is that for a steel-steel contact (approximately 0.5- 0.8). In this case, to achieve self-rotation, the angle (0) must exceed the angle (©balanced) where the force of gravity down the slope of the ramp 402 is exactly balanced by the maximum static force of friction (F _M ax), which can be calculated as tan(0 _b aianced)=p _s . For a steel-steel contact, ©balanced is approximately 27-39 degrees, and as such an angle (0) of approximately 40 degrees or more should be sufficient to overcome the static friction.

I n a further example, the angle (0) of the slope to the horizontal of the ramps 402 may vary along its length such that ©balanced is exceeded on some parts of the slope but is equal to or less than ©balanced on other parts of the slope. This has the result that the runners 203 accelerate whilst sliding along those parts where ©balanced is exceeded, but coast along or decelerate where ©balanced is matched or where the angle (0) is less than ©balanced. This can prevent excessive acceleration of the runners 203. An example of this is shown in Fig. 4 where the ramp 402 has a steep section 402a and a more shallow section 402b. To reduce the angle required, the runners 203 are preferably shaped to have a low area of contact (i.e. , a square centimetre or less) with the ramps 402, and may be formed of a low-friction material (i.e., having a static coefficient of friction with steel of less than 0.2, such as Teflon™). The ramps may similarly be formed of a low-friction material.

In another example, the runners 203 may be replaced with rollers or wheels, such that the slope of the ramps 402 may be substantially more shallow than ©balanced for simple frictional sliding, and preferably still achieve self-rotation under the influence of gravity.

In embodiments that do not comprise the latches 401 , the slope of the ramps 402 may be substantially steeper than 0 _ba ianced near and/or at the operating position so as to hold the runners 203 at the operating position. The slope angle near the operating position may be greater than 70 degrees, greater than 80 degrees, or substantially 90 degrees. In some embodiments, there may be provided a recess at the operating position, where the runners 203 are arranged to fit within the recess.

As shown in Fig. 7, a similar ramp/runner arrangement may be provided between the lid 300 and the attachment 200. Ramps 210 may be provided as cut-outs in the inner wall of the attachment 200. Runners 302 on the lid 300 may slid down the ramps 210 until they locate beneath vertical retention tabs 211 extending inwardly from the inner wall of the attachment 200. Once located in the correct orientation, the actuator 303 of the lid 300 may actuate a push-rod (not shown) in the column 209 to actuate a microswitch (or other interlock) in the base 400 to indicate that the lid 300 is correctly attached. The actuator 303 may also releasably lock with the button 208. For example, the button 208 may be spring-loaded upwards such that the actuator 303, when rotated towards the locking position, slides over the button 208 and enters a recess provided thereon. The lid 300 may therefore be freed to rotate by depressing the button 208 against the force of the spring.

Whilst the ramps 402 are shown as provided on the base 400, and the runners 203 are shown as being provided on the attachment 200, the ramps may instead be provided on the attachment 200 facing downwards and the runners may be provided on the base facing upwards. However, it is preferable to provide the ramps 402 on the base 400 as these are heavier than the runners 203 and the attachment 200 is the component most likely to be manually manipulated. Additionally, multiple attachments 200 may be used with a single base 400, so it is preferable to put the largest/most expensive item (the ramps 402) on the least numerous component for efficiency.

Lubricating oils/greases are preferably avoided on the attachment 200 and/or lid 300. This is to permit cleaning of the attachment 200/lid 300 in a dishwashing machine, which typically operates at temperatures which cause such oils to dry out. For similar reasons, the attachment 200/lid 300 is preferably made of a dishwasher-safe material that does not undergo chemical changes during prolonged exposure to the typical temperatures within a dishwashing machine. Examples of materials that are dishwasher-safe include glass, stainless steel, plastics including copolyesters such as Tritan™, and certain ceramics, but is not limited to these substances. Similarly, the attachment 200 and/or lid 300 is preferably formed of a food safe material. The attachment 200 and/or lid 300 are preferably transparent to permit the user to observer food processing going on within them.

The attachment 200 may be any one of: a chopper, juicer, blender, mincer, mixer, cooker, slicer, pasta-maker, ice-crusher, whisker, or other such food processing attachment. The base 400 may be any one of: a mixer, stand-mixer, blender-base, or food processor base.

Whilst the attachment 200 is portrayed as being lowered downwards onto the base 400, the attachment 200 may instead be an attachment that receives a motor-unit, such as, for example, an attachment for a hand-mixer or stick-blender. Typically in a hand-blender attachment the motor-unit mates with a motor-seat provided on the attachment (i.e. , on a lid), and where the motor-seat comprises a suitable drive-shaft and gearing for conveying rotational drive from the motor unit to the tool of the attachment. In this circumstance the runners 203 may be provided on the motor unit and the ramps 402 may be provided on the attachment 200, such that the motor-unit self-rotates to the correct orientation for locking engagement in the fashion already described.

Whilst a cylindrical protrusion 404 of the base 400 is shown mating with a rim 205 of the attachment 200, the protrusion may instead be provided on the attachment 200, with the rim formed on the base 400. The rim 205 may be omitted and the runners 203 may simply protrude directly from the bottom of the attachment 200, however it is preferably that they extend inwards from the rim 205 as this provides support and means the runners 203 need not be so large, thus reducing friction and increasing efficiency.

Whilst the bi-directional latches 401 are depicted as being in lands (i.e., flat sections) between the ramps 402, the upper surface of the base 400 on which the ramps 402 are formed may present a continuous sloped surface, for example it may be circumferentially shaped like a sine-wave or saw-tooth with no flat sections.

Whilst the attachment 200 and the base 400 have been described as being guided towards a locking position by the force of gravity when arranged so that one is vertically above the other, the ramp/runner arrangement is also useful in other circumstances. For example, when pressed together horizontally by e.g. hand, the runners 203 will still run over the surface of the ramps 402 so as to guide the attachment 200 towards the locking position.

Whilst the food processing tool is described as being included in the attachment 200, the lid 300 may alternatively or additionally include a food processing tool such as a rotary cutting tool or heating element.

“Food safe” in this context means any substance that does not shed substances harmful to human health in clinically significant quantities if ingested. For example, it should be BPA-free.

“Dishwasher safe” means that it should be physically and chemically stable during prolonged exposure to the conditions prevailing within a dishwasher machine. For example it should be able to withstand exposure to a mixture of water and a typical dishwasher substance (e.g., washing with Fairy™ or Finish™ dishwasher tablets and water, at temperatures of 82 degrees centigrade for as long as 8 hours without visibly degrading (e.g., cracking)).

It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.

Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.