WO2023089306A1

WO2023089306A1 - Kitchen appliance attachment

Info

Publication number: WO2023089306A1
Application number: PCT/GB2022/052887
Authority: WO
Inventors: Derren Knight; Steve PURVEY
Original assignee: Kenwood Limited
Priority date: 2021-11-17
Filing date: 2022-11-14
Publication date: 2023-05-25

Abstract

An attachment (100) for a kitchen appliance is disclosed. The attachment (100) is adapted to receive a tool plate (120) having a working surface (122) for processing foodstuffs. The attachment (100) is further adapted to restrain rotational and/or axial movement of the tool plate (120) relative to the attachment (100).

Description

Kitchen appliance attachment Field The present invention relates to an attachment in particular for a kitchen appliance such as a food preparation appliance, in particular an attachment for receiving and restraining movement of a tool plate such as a sieve. Background Sieving is a process of directing food through a grid, grille, or other apertured arrangement, with apertures sized such that a desired food product (e.g., flour, fruit puree) is allowed through whilst an undesired element (e.g., seeds, pips, pulp etc.) is retained on the grid. In this way a desired food product is obtained that is relatively free of the undesired element. Preferably, sieving is performed with tools having different aperture-sizes so that different undesired elements can be excluded. A known sieving attachment for a food preparation appliance comprises a shallow bowl with an aperture in the bottom surrounded by a concentric bottom surface of the shallow bowl, into which is removably located a flat, apertured sieve-plate. The sieve plate can be replaced by other sieve-plates having differing aperture sizes. The shallow bowl is then placed inside a deeper bowl of the food processing appliance, typically with its rim resting on a lip of the deeper bowl and the sieve suspended above a bottom of the inside surface of the deeper bowl. The food product to be sieved is forced through the sieve-plate by a rotating paddle of the food processing appliance that pushes the food product against the grid. The desired food product that extrudes through the grid then drops into the deeper bowl where it collects for consumption or further processing. When deployed as an attachment within the bowl of a stand-mixer (typically a C-shaped appliance where a driven tool is suspended over a bowl to do work on the food therein, such as that shown in Fig.1) the above-described attachment has the drawback that the sieve-plate tends to move during use due to the force of the paddle against it. This can lead to an unpleasant rattling noise, or even the sieve co-rotating with the paddle, which reduces its effectiveness. A further draw-back of this arrangement is that the user tends to tilt the shallow bowl so that they can access the underside of the sieve-plate to scrape off food-product adhering there, but this can lead to the sieve-plate falling out of the shallow bowl, potentially releasing the undesired food element accumulated on the upper side of the sieve-plate into the deeper bowl. Yet another drawback of this arrangement is that the attachment forms a “dead zone” along the horizontally-extending concentric bottom surface of the shallow bowl surrounding the sieve-plate where food accumulates without being processed. The present invention aims to at least partially ameliorate the above-described problems of the prior art. Summary of the Invention Aspects and embodiments of the present invention are set out in the appended claims. These and other aspects and embodiments of the invention are also described herein. According to an aspect, there is provided an attachment for a kitchen appliance, wherein the attachment is adapted to receive a tool plate having a working surface for processing foodstuffs, and wherein the attachment is adapted to restrain rotational and/or axial movement of the tool plate relative to the attachment. The attachment may further comprise one or more first engagement elements for engaging corresponding one or more second engagement elements on the tool plate to thereby restrain rotational movement of the tool plate. The first engagement element may comprise one or more pairs of ribs for receiving and restraining corresponding second engagement elements therebetween. The second engagement elements are preferably arranged on the periphery of the tool plate. The attachment is preferably adapted to axially clamp the tool plate. The attachment preferably comprises: a first member for receiving the tool plate, and a second member for exerting an axial force on the tool plate towards the first member (to co-operatively axially restrain the tool plate therebetween). The attachment may include an outer wall having an inwardly-extending element (preferably lip or flange) for receiving the tool plate. Preferably, the attachment is adapted to bidirectionally restrain axial movement of the tool plate relative to the attachment. The attachment may comprise an outer bowl and an inner bowl. The inner bowl may be configured to be removably attachable to the outer bowl. The inner bowl and the outer bowl may be configured to axially clamp the tool plate therebetween, thereby at least axially restraining movement between the attachment and the tool plate. Preferably, the outer bowl comprises the first member as described herein, and the inner bowl comprises the second member as described herein. The first member may be a lip of the outer bowl. The second member may be a sidewall of the inner bowl. Preferably, each of the inner bowl and the outer bowl is open at two opposite ends. One or preferably both bowls may have an aperture in their base. The attachment may be adapted to restrain rotational movement between the inner bowl and the outer bowl. Preferably, the inner bowl further comprises one or more third engagement elements, and the outer bowl further comprises one or more fourth engagement elements for engaging the one or more third engagement elements to restrain rotational movement of the inner bowl relative to the outer bowl; more preferably wherein one of the outer bowl and the inner bowl comprises one or more ribs, and the other of the outer bowl and the inner bowl comprises one or more recesses configured for receiving the ribs. Optionally, one element (preferably a rib of the outer bowl) acts as both the fourth engagement element and the first engagement element as described herein. Optionally, the outer bowl comprises ribs, which engage with both the tool plate and the inner bowl and are adapted for restraining rotational movement of the tool plate and the inner bowl relative to the outer bowl. The recesses are preferably blind.

Preferably, the inner bowl and the outer bowl are configured to be releasably attachable to each other. Optionally, the inner bowl and the outer bowl are configured to be releasably attachable to each other via handles (preferably extending radially outwards from the respective bowls) provided at each of the inner and outer bowl and adapted for interlocking with one another; preferably wherein the handles of the inner and the outer bowl are configured to co-operatively form a combination handle whereby the assembled attachment is manipulable by the user. Preferably, the attachment further comprises a first opening and a second opening at an opposite end of the attachment to the first opening; wherein the attachment is adapted to retain the tool plate adjacent the first opening such that, in use, the tool covers the first opening. Preferably, the attachment (more preferably the outer bowl) comprises an outwardly-folded lip surrounding the second opening, for greater rigidity. Preferably, the attachment further comprises an inwardly-extending lip surrounding the first opening configured for receiving the tool plate. The attachment may further comprise a sidewall having an inner surface for channelling foodstuffs towards the tool plate working surface. Preferably, the inner surface is adapted to receive a pressing tool such that the pressing tool abuts the inner surface. The inner surface is preferably arranged inwardly from the receiving element. The inner/running surface is located clear of the receiving element (e.g. lip) allowing a through path for food processing. This allows preventing the formation of a dead zone underneath the tool plate enclosed by the inner surface. The inner surface is preferably smooth and featureless (so as to not obstruct food within the inner surface), and is more preferably made of or coated with a low-friction material, preferably PTFE. Optionally, the sidewall and/or the receiving element restrain rotational movement of the tool plate relative to the attachment via friction. The attachment may be adapted to provide a clear path for foodstuffs on either side of the tool plate working surface within the inner surface. Preferably, in use, the working surface enclosed by the sidewall is exposed (i.e. unobstructed) on either side, more preferably such that foodstuffs (i.e. ‘foodstuff’) does not accumulate at either side of the working surface. Preferably, the sidewall and the receiving element are arranged to co-operatively axially restrain the tool plate therebetween; more preferably wherein the sidewall and the receiving element are adapted to apply an axial force on either side of the tool plate to restrain axial movement of the tool plate relative to the attachment. Preferably, the receiving element extends inwardly from a sidewall of the outer bowl. Preferably, the inner surface is provided by an inner surface of a sidewall of the inner bowl. Preferably, the receiving element extends inwardly from a sidewall of the outer bowl. Preferably, the attachment is adapted to interchangeably removably retain a plurality of tool plates, each tool plate having a different working surface for processing foodstuffs (i.e. for carrying out differing food processing activities). Preferably, each tool plate has differently sized and/or shaped apertures. The attachment may further comprise one or more formations (e.g. protrusions or recesses) adapted, when the outer bowl is placed within a food processing bowl, to restrain rotational movement of the attachment relative to the food processing bowl. Preferably, the formations comprise protrusions. Preferably, the food processing bowl includes handles, and the formations abut the food processing bowl handles. The attachment may further comprise a food processing bowl, wherein the attachment is configured to sit within an opening of the food processing bowl such that the tool plate is raised above a bottom of the food processing bowl for accommodating food processed through the tool plate. Preferably, the attachment further comprises a lid locatable over the attachment (more preferably over the second opening thereof) to close it for preventing splashing out of the attachment.

The attachment may further comprise a pressing tool configured to be attachable to a drive outlet of a food processing device to press food material towards (preferably through (apertures in)) the working surface of the tool plate; preferably wherein the pressing tool comprises rotatable resilient paddles for pushing food material towards the tool plate. Optionally, the attachment further comprises a tool plate arranged in the attachment. According to another aspect, there is provided a tool plate for an attachment for a kitchen appliance, the attachment preferably being as described herein, the tool plate comprising: a working surface for processing foodstuffs, and one or more formations, preferably protrusions, for engagement with the attachment. Preferably, the tool plate working surface comprises (i.e. is provided with) a plurality of apertures for processing foodstuffs (more preferably passing therethrough). Preferably, the apertures extend throughout the working surface – i.e. the apertures are provided across the working surface. Preferably, the (the working surface of the) tool plate is one of a sieve, grater, or slicer. Preferably, the tool plate is removably attachable to the attachment. Preferably, at least the working surface of the tool plate is flat. The tool plate may comprise a curved (or otherwise non-flat) surface around the working surface. Preferably, the entire tool plate is flat. It should be appreciated that the tool plate is preferably thin (i.e. its thickness is (more preferably significantly) smaller than its ‘main’ surface), but the term “tool plate” is preferably not limited as such. According to another aspect, there is provided a combination, comprising at least two tool plates as described herein, each tool plate having matching formations for engagement with the attachment, preferably each tool plate having a different working surface for processing foodstuffs (for carrying out differing food processing activities). According to another aspect, there is provided a kitchen appliance including the attachment as described herein, the kitchen appliance preferably being either a stand- mixer or a bottom-driven food processor. The kitchen appliance may be a food processing device. The kitchen appliance may further comprise a heating element configured to heat food material pushed towards the tool plate; the kitchen appliance preferably further comprising a processor configured to control the heating of the heating element based on feedback from temperature sensors. The kitchen appliance may include the attachment as described herein, wherein the kitchen appliance further comprises a processor configured to control driving of the pressing tool based on sensed torque of the pressing tool. According to another aspect, there is provided a kit of parts comprising: the attachment as described herein; and one or more tool plates, preferably as described herein, each tool plate having a working surface for processing foodstuffs, and each tool plate being adapted for restraining by the attachment. According to another aspect, there is provided an attachment for a kitchen appliance, wherein the attachment is adapted to receive a tool plate having a working surface for processing foodstuffs; and wherein the attachment is adapted to restrain movement of the tool plate laterally and in at least one further direction (e.g. axially and/or radially). According to another aspect, there is provided an attachment for a kitchen appliance, wherein the attachment is adapted to receive a tool plate having a working surface for processing foodstuffs; and wherein the attachment is adapted to restrain lateral and downward (in use) movement of the tool plate relative to the attachment, and further adapted to restrain movement of the tool plate relative to the attachment in at least one further direction. According to another aspect, there is provided an attachment for a kitchen appliance, wherein the attachment is adapted to receive a tool plate having a working surface for processing foodstuffs; and wherein the attachment is adapted to restrain angular (i.e. rotational) movement of the tool plate relative to the attachment in at least one direction. In other words, taking the centre of the tool plate as the origin and a line along the tool plate surface as the zenith direction, the attachment is adapted to restrain angular movement of the tool plate relative to the attachment along a polar angle and/or along an azimuthal angle. According to another aspect, there is provided an attachment for a kitchen appliance having a food processing bowl; wherein the attachment is adapted to receive a tool plate having a working surface for processing foodstuffs, and to sit within an opening of the food processing bowl such that the tool plate is raised above a bottom of the food processing bowl for accommodating foodstuffs processed by the tool plate working surface; wherein the attachment is adapted to constrain axial movement of the tool plate towards the bottom of the food processing bowl, and to further constrain rotational movement of the tool plate relative to the attachment and/or axial movement of the tool plate away from the bottom of the food processing bowl. According to another aspect, there is provided an attachment for a kitchen appliance, the attachment being adapted to removably retain a tool plate having a working surface for processing foodstuffs. Preferably, the attachment is adapted to axially retain the tool plate. Preferably, the attachment is adapted to rotationally retain the tool plate. According to another aspect, there is provided anattachment for a food processing device comprising: an outer bowl with a first opening, and a second opening at an opposite end of the outer bowl to the first opening, a first tool-plate configured to be removably attachable within the first opening to substantially cover it, the first tool plate having a working surface with apertures defined extending therethrough, which faces towards the second opening when the tool-plate is located within the first opening (i.e. aperture), for permitting food to be brought into contact with the working surface through the second opening, an inner bowl having openings corresponding to the first and second openings of the outer bowl, the inner bowl configured to be removably attachable within the outer bowl so as to co-operatively retain the tool-plate therebetween. Preferably, the inner bowl and the outer bowl are configured to cooperatively retain the tool-plate both rotationally and axially when attached to each other. Preferably, the first tool-plate is rotationally retained by inter-engagement of a protrusion on one of the first tool-plate and the outer bowl with a recess on the other of the first tool plate and the outer bowl. Preferably, the attachment is configured such that the inner bowl and/or outer bowl forms a sealed contact with the first tool-plate when assembled thereto. Preferably, the sealed contact is formed by resilient pressing of the inner and/or outer bowl against the first tool- plate. Preferably, the sealed contact comprises a rubber seal. Optionally, the inner bowl presents a substantially smooth, featureless inner surface, and is preferably made of or coated with a low-friction substance, preferably PTFE. Preferably, the inner bowl and outer bowl are configured to be releasably attachable to each other via a handle of one interlocking with a recess of the other. Preferably, the handle is provided extending radially outwards from the inner bowl, and engages with a recess defined by a radially-outward-extending ear of the outer-bowl, and where the handle and ear are configured to co-operatively form a combination handle whereby the assembled attachment is manipulable by the user. Preferably, the attachment further comprises one or more additional tool-plates interchangeable with the first tool-plate, wherein the additional tool-plates have differing working-surfaces to the first tool-plate for carrying out differing food processing activities. Preferably, the one or more additional tool-plates have differently sized and/or shaped apertures defined through them in their working-surfaces to the apertures provided in the working-surface of the first tool-plate.

Preferably, the one of the outer bowl or the inner bowl has axially-extending ribs formed thereon, the ribs being configured on assembly of the inner bowl to the outer bowl to be received within corresponding recesses of the other of the inner bowl and outer bowl, for helping to prevent relative rotation between the inner bowl and the outer bowl. Preferably, the outer bowl comprises an outwardly-folded lip surrounding the second opening for greater rigidity. Preferably, the outer bowl comprises an inwardly-extending lip surrounding the first opening configured for receiving the first tool-plate. Preferably, wherein the first tool-plate is one of a sieve, grater, or slicer. Preferably, the attachment further comprises a food processing bowl, wherein the outer bowl is configured to sit within an opening of the food processing bowl with the first tool- plate raised above a bottom of the food processing bowl for accommodating food processed through the first tool plate. Preferably, the food processing bowl comprises one or more food processing bowl handles, and the outer bowl comprises one or more protrusions configured when the outer bowl is placed within the food processing bowl to abut with the food processing bowl handles to rotationally retain the outer bowl relative to the food processing bowl. Preferably, the attachment further comprises a lid locatable over the second opening to close it for preventing splashing out of the attachment. Preferably, the attachment further comprises a pressing tool configured to be attachable to a drive outlet of a food processing device to press food material through the apertures of the working-surface of the first tool-plate. Preferably, the pressing tool comprises rotatable resilient paddles for pushing food material through the first tool-plate. The attachment is preferably made of a food-safe and/or dishwasher-safe material. According to another aspect, there is provided a food processing device comprising the attachment of as described herein, the food processing device preferably being either a stand-mixer or a bottom-driven food processor. Preferably, the food processing device further comprises a heating element configured to heat food material pushed through the first tool-plate. Preferably, the food processing device further comprises a processor configured to control the heating of the heating element based on feedback from temperature sensors. The food processing device preferably comprising the attachment as described herein, wherein the food processing device comprises a processor configured to control driving of the pressing-tool based on sensed torque of the pressing tool. 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 appliances, 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. Any reference to “food”, “beverage” (or similar language) herein may be replaced by such working mediums. The invention described here may be used in any appliance, such as a kitchen appliance, and/or as a stand-alone device. This includes any domestic food-processing and/or preparation appliance, including both top-driven appliances (e.g., stand-mixers) and bottom-driven appliances (e.g., food processors). It may be implemented in heated and/or cooled appliances. The invention may also be implemented in both hand-held (e.g., hand blenders) and table-top (e.g., blenders) appliances. It may be used in an appliance 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, whether motor-driven or manually powered. As used herein, the term “processing” preferably connotes any action relating to or contributing towards transforming products into foodstuff, or transforming foodstuff into a different form of foodstuff, including – as examples - applying mechanical work (e.g. for cutting, beating, blending, whisking, dicing, spiralising, grinding, extruding, shaping, kneading etc.) and applying heat or cold. “Food” and “foodstuff” as used herein can include beverages and frozen material and material used in creating them (e.g., coffee beans). “Food processing” as described herein should be taken to encompass chopping, whisking, stirring, kneading, mincing, grinding, shaping, shredding, grating, cooking, freezing, making ice-cream, juicing (centrifugally or with a scroll), or other food-processing activities involving the physical and/or chemical transformation of food and/or beverage material by mechanical, chemical, and/or thermal means. “Food processing attachment” encompasses any attachable component configured, for example on rotation and/or energising, to carry out any of the previously described food processing tasks. The invention extends to methods, system and apparatus substantially as herein described and/or as illustrated with reference to the accompanying figures. The invention extends to any novel aspects or features described and/or illustrated herein. 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, for example. 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 stand mixer of the prior art; Fig.2 shows an exploded, perspective drawing of an attachment according to the present invention; Fig.3 shows a side-on view through a section of the assembled attachment of Fig.2; Fig.4 shows a side-on view through a section of the assembled attachment of Fig.1 when located in the bowl of the stand mixer of Fig.1; Fig.5 shows a simplified, schematic, cut-away view of bowl with attachment of Fig.4 when located on a stand mixer, and,

Fig. 6 shows a simplified, schematic, cut-away view of an attachment according to a second embodiment attached to a food processor. Specific Description The present disclosure is described with particular reference to a sieve 120 which serves as an example of a tool plate and to a corresponding sieve attachment 100 which serves as an example of an attachment for retaining the tool. It should be appreciated that the disclosure is equally applicable to retention of other tool plates such as cutters or graters. Fig.2 shows a sieve attachment 100 designed to be fitted in the bowl 16 the stand mixer 10 of Fig.1. The stand mixer 10 of Fig.1 comprises a horizontally-extending base 11 from one end of which extends a vertical stand 12 having a motor control-knob 12a and a head-release switch 12b. A horizontally-extending head unit 13 extends from the opposite end of the stand 12 to that which meets the base 11, substantially in parallel to the base 11, which it also over-hangs. The head unit 13 has an upper drive outlet 13a facing away from the base 11, and a horizontal drive outlet 13b facing away from the stand 12. The head unit 13 can pivot away from the base 11 when the head-release switch 12b is actuated. A lower, planetary drive outlet 14 depends from the head 13 towards the base 11 facing a bowl 16 releasably located in a suitable niche on the base 11. The planetary drive outlet 14 has an off-centre located tool-attachment point 15 to which tools may be attached for performing work in the bowl 16. The outlets 13a, 13b, and 14 receive rotary drive from a motor or motors located in either, or both of, the stand 12 and the head 13, via suitable gearing, with the speed of the motor/motors variable using the control knob 13a. The sieve attachment 100 of Fig. 2 comprises an inner bowl 110, two or more interchangeable sieves 120 each having differently-sized and/or shaped apertures, and an outer bowl 130 designed to sit within the bowl 16 supporting a sieve 120 and the inner bowl 110 concentrically located within it. When assembled, the sieve 120 is retained both axially (so as to prevent the sieve 120 from falling out when the attachment 100 is tilted) and rotationally (so as to prevent co-rotation of the sieve 120 with tool 200) between/by the inner bowl 110 and the outer bowl 130. The bowl 16 in turn can be secured to the stand mixer 10 using the base 16b of the bowl 16, which can comprise suitable fixing means such as a bayonet fixing or similar. The bowl 16 is also provided with handles 16a so that the bowl 16 can be more easily handled by the user. The inner bowl 110 has a substantially vertically-oriented cylindrical wall (i.e. sidewall) 111 with a smooth, low friction (e.g., PTFE/Teflon^TM-coated) inner surface (i.e. running surface) for allowing food matter to slide off it during processing. At an upper end one or more, and preferably two, handles 112 are formed extending radially outwards from the cylindrical wall 111. The handles 112 may be substantially hoop-shaped so as to define a handle- hole 112a, and may also form and axially-extending hook 112b at a side that faces towards the outer bowl 130 when assembled therewith for latching thereto. An outer surface of the cylindrical wall 111 may have recesses 113 (i.e. third engagement elements) defined in it for receiving corresponding inwardly-facing ribs 133 of the outer bowl 130, which allows restraining relative rotation between the inner bowl 110 and outer bowl 130. The recesses 113 are partial/blind (i.e. do not extend right through the entire thickness of the inner bowl 110 side wall). This provides a smooth inner surface of the inner bowl 110 sidewall 111. In the example embodiment shown in Figure 2, the inner bowl 110 comprises two pairs of recesses 113 adjacent each handle 112, and the outer bowl 130 comprises two corresponding pairs of ribs 133 adjacent each ear 132 (only one pair of recesses 113 and ribs 133 being visible in Figure 2). The inner bowl 110 may have axially-extending strengthening ribs 114 formed on its outer surface The interchangeable sieves 120 each comprise a plate having apertures of differing shapes and sizes for allowing and excluding the passage of differing food material. In this way differing material can be sieved by swapping one sieve 120 for another. Each sieve 120 has one or more locating features 121 (i.e. second engagement elements) formed on it. For example, this feature 121 can be a radially-outwardly-extending protrusion that extends to abut against the ribs 133 (i.e. first and fourth engagement elements) of the outer bowl 130 to prevent rotation of the sieve 120 relative to the outer bowl 130, meaning that co-rotation of the sieve 120 with the tool 200 is prevented. In the example embodiment shown in Figure 2, each sieve 120 comprises two locating features 121, and the outer bowl 130 comprises two corresponding pairs of ribs 133 (only one pair of ribs 133 being visible in Figure 2). The features 121 rest on the lip 131 between ribs 133 which thereby prevent rotation of the sieve 120 relative to the outer bowl 130. Alternatively, the outer bowl 130 may comprise partial cut-outs arranged to receive the features 121 and rotationally retain the sieve 120. In a yet further alternative, the sieve 120 may be rotationally retained via friction between the sieve 120 and the inner bowl 110 and/or outer bowl 130. When the sieve 120 is located between the inner bowl 110 and outer bowl 130, its apertured surface is exposed upwardly through the inner bowl 110 such that a tool 200 can extend axially through the inner bowl 110 to contact the apertured surface of the sieve 120, with no feature blocking access to it and/or acting as a “food trap” (i.e., a point on the attachment where food product collects unprocessed). Thus, the inner bowl 110 and the outer bowl 130 co-operatively retain the sieve 120 in such a way that movement of the sieve-plate during use and tilting is reduced, whilst food traps are avoided (in contrast, if retaining features were provided above or below the sieve 120, these features would collect food product against them during use of the attachment, reducing the effectiveness of the attachment). Eliminating food traps is further important in that they are also potentially unsanitary as they may be hard to clean. Further, the inner bowl 110 and the outer bowl 130 provide for removable retention of the sieve 120. This is advantageous over fixed/permanent retention because providing the sieve 120 fixed or integral with either bowl 110 or 130 would make it difficult to vary the aperture size of the sieve 120. The apertures of the sieve 120 may only be present in a central area 122 of the sieve 120, with the area surrounding it (e.g., that area that contacts the lower edge of the cylindrical wall 111) being free of apertures to improve sealing. The cylindrical wall 111 of the inner bowl 110 may also have a sealing element such as, for example, a rubber seal, that extends from the lower edge of the wall 111 to contact the sieve 120 and/or from the sieve 120 towards the wall 111 to seal a gap therebetween and prevent ingress of food material therethrough. The outer bowl 130 may similarly form a sealed contact with the sieve 120 when assembled to it, including by having an intervening rubber seal provided on the outer bowl 130 and/or the sieve 120. Alternatively a seal between the outer bowl 130 and/or inner bowl 110 and the sieve 120 may be formed simply by resilient pressure of the inner bowl 130 and/or inner bowl 110 against the sieve created by resilience of the inner bowl 130 and/or inner bowl 110 and their inter-connection pushing them against the sieve 120. The sieves 120 may be metal plates (e.g., stainless steel) with apertures punched, lasered, drilled, or otherwise formed in them. Alternatively they may be made of a relatively stiff wire mesh. A stiff metal hoop or rib may be formed peripherally on the sieves 120 to aid in rigidity. The hoop or rib may interlock with a corresponding recess of the inner bowl 110 or outer bowl 130 to aid in locating of the sieve 120 relative thereto. As is shown particularly in Fig. 3, the outer bowl 130 can mate with the inner bowl 110. The outer bowl 130 forms an axially-extending cylindrical wall with a greater inner diameter than that of the cylindrical wall 111 so as to substantially surround the inner bowl 110 when they are locked together. This is achieved by ear elements (i.e. outer bowl handles) 132 which have protrusions 132a and indents 132b designed to interlock with the (inner bowl) handles 112 to facilitate engagement between the inner bowl 110 and outer bowl 130 and to restrain their relative rotation. This may be achieved by, for example, the handles 112 being received in the indent 132b and the protrusions 132a being received in the holes 112a of the handles 112. For additional security, the hooks 112b of the handles 112 hooking beneath the ear elements 132. To facilitate this inter-engagement, either or both of the handles 112 and ears 132 may be made of a resilient material such as nylon or spring-steel. The combination of the ears 132 and the handles 112 allows more convenient handling of the inner bowl 110 and outer bowl 130 by the user both when combined and when separated. The positioning of the ears 132 and handles 112 on the upper extremity of the attachment, at or near their combined upper aperture through which food is inserted for processing, and outside the working zone of the tool 200 (i.e., outside and above the volume that it sweeps through during sieving), also helps avoid food collecting in and around the indents and protrusions of them.

As can be seen in Fig.3, a gap may form between the inner bowl 110 and the outer bowl 130 when they are assembled together, and food may potentially enter into this gap, particularly where no seal is present between the inner bowl 110 and the sieve 120. However, as the inner bowl 110 and outer bowl 130 can be easily disassembled from each other by manually unhooking the hooks 112b from the outer bowl 130 and removing the handles 112 from the indents 132b, the user can easily access this gap to wash it manually. Alternatively the user may disassemble the inner bowl 110, outer bowl 130, and sieve 120 from each other and place them in a dishwasher for washing. To facilitate this the attachment 100 should preferably be made of a dishwasher-safe material. The attachment 100 should also preferably be made of a food-safe material. The sieve is supported on an inner-lip 131 extending inwards from a lower edge of the cylindrical wall of the outer bowl 130. In this way when the inner bowl 110 and the outer bowl 130 are joined together with the sieve 120 placed between them resting between the inner-lip 131 and the lower edge of the wall 111, it is held axially between them and cannot fall out if the attachment 100 is tilted. The lip 131 also helps promote rigidity of the outer bowl 130. The lip 131 may alternatively be replaced with other elements for retaining/receiving the sieve 120 (i.e. with other receiving elements), such as inwardly- protruding tabs, or bars extending across the lower opening of the outer bowl 130. As is shown in Figs.3 and 4, the outer bowl 130 locates into the bowl 16 and rests against an upper rim of it. The outer bowl 130 may form an outwardly-extending outer-lip 135 at its upper edge such that inter-engagement of the outer-lip 135 with the lip of the bowl 16 prevents the attachment 100 falling into the bowl 16. For added strength, the outer-lip 135 may form a fold-section where the outer-lip 135 folds outwardly and downwardly back along part of the axial extent of the cylindrical wall of the outer bowl 130. Rotation of the attachment 100 relative to the bowl 16 may be prevented by the frictional contact therebetween. For example, the outer bowl 130 may have an outer surface formed of a relatively high-friction substance like surface-roughened rubber. Alternatively or additionally, the outer bowl 130 may form axially/radially-extending protrusions 134 that extend to abut with features of the bowl 16 (e.g., the handles 16a) to prevent rotation of the attachment 100 relative to the bowl 16. Optionally, the protrusions 134 may lock (i.e. engage) with the handles 16a – e.g. via a snap fit lock. As shown in Fig. 4, a tool 200 may extend down through the upper opening of the attachment 100 into contact with the sieve 120 locked between the outer bowl 130 and the inner bowl 110 for assisting in pressing food material through the sieve 120. The tool 200 comprises a central axially-extending shaft 210 with fixing elements 220 formed thereon which allow fixing of the tool 200 to, for example, the tool attachment point 15 of the planetary outlet 14 of the stand mixer 10. One or more arms 230 extend radially from the shaft 210, from which pressing elements 240 extend radially downwards into contact with the sieve 120 for pressing food matter therethrough. The pressing elements 240 may be paddle-shaped elements, and are preferably made of a resilient material such as rubber or spring steel such that they can resiliently press food through the sieve 120, and ride over hard elements deposited on the sieve 120. To facilitate planetary action, the radial diameter of the tool 200 should preferably be at least half that of the exposed surface of the sieve 120, and more preferably approximately 2/3rds. The inner bowl sidewall 111 has a convex side profile and the inner surface of the inner bowl side wall 111 is smooth. This allows the arms 230 of the tool 200 to cover substantially the entire sieve 120 working surface enclosed by the sidewall 111. As a result, foodstuffs can be processed through substantially the entire sieve 120 working surface 122 enclosed by the sidewall 111, and the inner surface of sidewall 111 provides a running side surface with no dead zone for food processing. Fig.5 shows the attachment 100 deployed in a stand mixer 300 that is similar to the stand mixer 10 except for the differences in the following description. A heating element 311a is provided on the base 311 of the stand mixer 300 for heating the contents of the bowl 316. It is thus possible to heat food material that drops downwards into the bowl 316 from the attachment 100 after being forced through the sieve 120 by the tool 200. As such, for example, fruit material pureed or juiced through the sieve 120 can be reduced to make sauces or jams by heating. The base of the bowl 316 may have suitable apertures through which temperature sensors (not shown) can extend to contact with the bowl 316 for controlling the heating of the bowl. The sensors may communicate with a processor 317 housed in the stand section 312 of the stand mixer 300 (or elsewhere) which may control the heating element 311a based on user input. For example, if the user selects a “Jam-making” or “sauce-making” option using a suitable user interface (e.g., touch-screen interface) the stand mixer 300 may indicate to the user that the attachment 100 should be used, and that any required additional ingredients (e.g., sugar) be placed inside the bowl. Once the user confirms that the attachment 100 is attached and that a suitable quantity of e.g., fruit is located in the attachment (e.g., by selecting “OK” in the user interface) the stand mixer 300 may activate a motor located e.g., in the head unit 313 of the stand mixer 300 to drive the planetary drive outlet 314 with a tool attachment point 315 to which the tool 200 is attached. Once sufficient juice/puree has been pushed through the sieve 120, which may be determined by the processor 317 either according to time passed since the motor was activated (e.g., 2-5 minutes) or sensed according to e.g., variations and levels of torque experienced by the tool 200 and sensed by a suitable sensor, the heating element 311a is activated. Heating may be ended either by a user interaction, or by a suitable temperature being reached (e.g., a jam-setting temperature of e.g., 105 degrees C) preferably for a predetermined amount of time (e.g., 30 seconds), or by a weight-sensor associated with the base 311 sensing that sufficient water has been evaporated from the bowl 316 that a sauce has been reduced to a desired thickness. The stand mixer 300 may then indicate to the user using either sounds, lights, a touch-screen interface, notices delivered to a user device such as a mobile phone, or otherwise, that their desired sauce or jam is ready. Fig. 6 shows the attachment 100 deployed in the bowl 600 of a bottom-driven food processor 400. The principle of operation here is similar to that described in the stand mixers 10 and 300 above, except as described in the following. In the food processor 400, instead of being driven from overhead, the tool 700 is instead driven by a motor 501 located in a base unit 500 via a drive-shaft 800 that extends through an aperture in the bottom of the bowl 600 and through a similar shaft-aperture provided centrally in the sieve 120 to connect with the tool 700 within the attachment 100. Rather than having planetary action, the tool 700 may simply rotate circularly around the axis of the shaft 800, and as such will have a diameter similar to the internal diameter of the inner bowl 110 so as to push food matter through the entire apertured area 122 of the sieve 120. The base 500 may include a heating element 503 with temperature probes contacting the bowl 600 similar to the heating element 311a. The base may also include a processor 502 that operates similarly to the processor 317 discussed above. The bowl 600 may also be enclosed by a lid 900 that also fits over the attachment 100 to prevent splashing of food material out of the bowl 600. The lid 900 may have a suitable peripheral seal formed at the point it meets the bowl 600 to seal the gap therebetween. To allow evaporated water to escape from the bowl 600, the lid 900 may have a closable vent in its upper surface, such that the user can chose to allow steam/vapour to escape or instead for it to remain in the bowl. A bearing point 910 may be provided centrally in the lid 900 for the shaft 800 to bear into and be supported by the lid 900. Radially-extending wipers 810 may also extend from shaft 800 to wipe a bottom of the sieve 120 to prevent food-matter adhering thereon. Preferably the wipers 810 extend so as not to coincide with the paddles of the tool 700 (i.e., they extend along different rotational directions to the paddles of the tool 700), such that they do not block food being pressed through the sieve 120 by the tool 700. Additionally stirring elements 820 may extend radially and axially from the shaft 800 towards the bottom of the bowl 600 to stir liquid or food matter accumulated there. The stirring elements 820 may be whisks or paddles, scrapers, or similar tools. In an alternative configuration, the shaft 800 may comprise multiple co-axial shafts rotating at different speeds and connecting to different tools. These coaxial shafts could be driven either by the motor 501 using a suitable gearing mechanism, or by independently actuatable motors. For example the tool 700 and wipers 810 could be driven by a first central shaft and the stirring elements 820 could be driven by a second hollow shaft surrounding the first central shaft. In such a configuration different tools could be driven at different speeds, for example the stirring elements 820 could be driven to rotate faster than the tool 700, to ensure more even cooking. Tools could also be driven independently of each other to avoid unnecessary processing by e.g., only engaging a gearing mechanism to provide rotary drive to one of the coaxial shafts where required. In each of the devices 10, 200, and 600 discussed above, the sieves 120 may be replaced by other plate-shaped tools. For example, the sieves 120 may be replaced with a (preferably similarly-shaped) grater or a cutting-disc which food material is moved over by a suitable tool replacing the tools 200/700 (e.g., an element such as a vice, grip, or claw to which vegetables, meat, or cheese can be attached) to carry out grating and/or cutting where the grated/sliced material falls into the bowl 16/360/600 beneath it. An additional plate without apertures, again similarly shaped to the sieves 120, may be provided which food can be mashed upon. As used herein, the term "removable attachment" (and similar terms such as “removably attachable”), as used in relation to an attachment between a first object and a second object, preferably connotes that the first object is attached to the second object and can be detached (and preferably re-attached, detached again, and so on, repetitively), and/or that the first object may be removed from the second object without damaging the first object or the second object; more preferably the term connotes that the first object may be re-attached to the second object without damaging the first object or the second object, and/or that the first object may be removed from (and optionally also re-attached to) the second object by hand and/or without the use of tools (e.g. screwdrivers, spanners, etc.). Mechanisms such as a snap-fit, a bayonet attachment, and a hand-rotatable locking nut may be used in this regard. As used herein, the term “restrain” (and similar terms such as “retain”), as used in relation to restraint of movement of a second object by a first object, preferably connotes that the second object is held in place by the first object such that movement of the second object is restricted (more preferably prevented) in one or more directions or senses. As used herein, the term “axially” (and similar terms such as “axial”), as used in relation to the attachment and the tool plate, preferably connotes a direction along a main axis of the attachment (typically vertical in use), more preferably a direction perpendicular to a working surface of the tool plate. “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^TM or Finish^TM 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. The following lists a number of aspects: 1. An attachment for a food processing device comprising: -an outer bowl with a first opening, and a second opening at an opposite end of the outer bowl to the first opening, -a first tool-plate configured to be removably attachable within the first opening to substantially cover it, the first tool plate having a working surface with apertures defined extending therethrough, which faces towards the second opening when the tool-plate is located within the first opening (i.e. aperture), for permitting food to be brought into contact with the working surface through the second opening, - an inner bowl having openings corresponding to the first and second openings of the outer bowl, the inner bowl configured to be removably attachable within the outer bowl so as to co-operatively retain the tool-plate therebetween. 2. The attachment of aspect 1 wherein the inner bowl and the outer bowl are configured to cooperatively retain the tool-plate both rotationally and axially when attached to each other. 3. The attachment of aspect 2 wherein the first tool-plate is rotationally retained by inter-engagement of a protrusion on one of the first tool-plate and the outer bowl with a recess on the other of the first tool plate and the outer bowl. 4. The attachment of any preceding aspect, wherein the attachment is configured such that the inner bowl and/or outer bowl forms a sealed contact with the first tool- plate when assembled thereto. 5. The attachment of aspect 4, wherein the sealed contact is formed by resilient pressing of the inner and/or outer bowl against the first tool-plate. 6. The attachment of aspects 4 or 5, wherein the sealed contact comprises a rubber seal. 7. The attachment of any preceding aspect, wherein the inner bowl presents a substantially smooth, featureless inner surface, and is preferably made of or coated with a low-friction substance, preferably PTFE. 8. The attachment of any preceding aspect, wherein the inner bowl and outer bowl are configured to be releasably attachable to each other via a handle of one interlocking with a recess of the other. 9. The attachment of aspect 8 wherein the handle is provided extending radially outwards from the inner bowl, and engages with a recess defined by a radially- outward-extending ear of the outer-bowl, and where the handle and ear are configured to co-operatively form a combination handle whereby the assembled attachment is manipulable by the user. 10. The attachment of any preceding aspect, further comprising one or more additional tool-plates interchangeable with the first tool-plate, wherein the additional tool- plates have differing working-surfaces to the first tool-plate for carrying out differing food processing activities. 11. The attachment of aspect 10, wherein the one or more additional tool-plates have differently sized and/or shaped apertures defined through them in their working- surfaces to the apertures provided in the working-surface of the first tool-plate. 12. The attachment of any preceding aspect, wherein the one of the outer bowl or the inner bowl has axially-extending ribs formed thereon, the ribs being configured on assembly of the inner bowl to the outer bowl to be received within corresponding recesses of the other of the inner bowl and outer bowl, for helping to prevent relative rotation between the inner bowl and the outer bowl. 13. The attachment of any preceding aspect, wherein the outer bowl comprises an outwardly-folded lip surrounding the second opening for greater rigidity. 14. The attachment of any preceding aspect, wherein the outer bowl comprises an inwardly-extending lip surrounding the first opening configured for receiving the first tool-plate. 15. The attachment of any preceding aspect, wherein the first tool-plate is one of a sieve, grater, or slicer. 16. The attachment of any preceding aspect, further comprising a food processing bowl, wherein the outer bowl is configured to sit within an opening of the food processing bowl with the first tool-plate raised above a bottom of the food processing bowl for accommodating food processed through the first tool plate. 17. The attachment of any preceding aspect, wherein the food processing bowl comprises one or more food processing bowl handles, and the outer bowl comprises one or more protrusions configured when the outer bowl is placed within the food processing bowl to abut with the food processing bowl handles to rotationally retain the outer bowl relative to the food processing bowl. 18. The attachment of any previous aspect, further comprising a lid locatable over the second opening to close it for preventing splashing out of the attachment. 19. The attachment of any previous aspect, further comprising a pressing tool configured to be attachable to a drive outlet of a food processing device to press food material through the apertures of the working-surface of the first tool-plate. 20. The attachment of any preceding aspect, preferably made of a food-safe and/or dishwasher-safe material. 21. The attachment of aspect 20, wherein the pressing tool comprises rotatable resilient paddles for pushing food material through the first tool-plate. 22. A food processing device comprising the attachment of any previous aspect, the food processing device preferably being either a stand-mixer or a bottom-driven food processor. 23. The food processing device of aspect 22, the food processing device further comprising a heating element configured to heat food material pushed through the first tool-plate. 24. The food processing device of aspect 23, the food processing device further comprising a processor configured to control the heating of the heating element based on feedback from temperature sensors. 25. The food processing device of any one of aspects 22-24 comprising the attachment of any one of aspects 20-21, wherein the food processing device comprises a processor configured to control driving of the pressing-tool based on sensed torque of the pressing tool.

Claims

CLAIMS: 1. An attachment for a kitchen appliance, wherein the attachment is adapted to receive a tool plate having a working surface for processing foodstuffs, and wherein the attachment is adapted to restrain rotational and/or axial movement of the tool plate relative to the attachment. 2. The attachment of claim 1, wherein the attachment further comprises one or more first engagement elements for engaging corresponding one or more second engagement elements on the tool plate to thereby restrain rotational movement of the tool plate. 3. The attachment of claim 2, wherein the first engagement element comprises one or more pairs of ribs for receiving and restraining corresponding second engagement elements therebetween. 4. The attachment of any preceding claim, wherein the attachment is adapted to axially clamp the tool plate. 5. The attachment of claim 4, wherein the attachment comprises: a first member for receiving the tool plate, and a second member for exerting an axial force on the tool plate towards the first member. 6. The attachment of any preceding claim, wherein the attachment includes an outer wall having an inwardly-extending element for receiving the tool plate. 7. The attachment of any preceding claim, wherein the attachment comprises an outer bowl and an inner bowl. 8. The attachment of claim 7, wherein the inner bowl is configured to be removably attachable to the outer bowl. 9. The attachment of claim 7 or claim 8, wherein the inner bowl and the outer bowl are configured to axially clamp the tool plate therebetween. 10. The attachment of any of claims 7 to 9, wherein the attachment is adapted to restrain rotational movement between the inner bowl and the outer bowl. 11. The attachment of claim 10, wherein the inner bowl further comprises one or more third engagement elements, and the outer bowl further comprises one or more fourth engagement elements for engaging the one or more third engagement elements to restrain rotational movement of the inner bowl relative to the outer bowl; preferably wherein one of the outer bowl and the inner bowl comprises one or more ribs, and the other of the outer bowl and the inner bowl comprises one or more recesses configured for receiving the ribs. 12. The attachment of any preceding claim, wherein the attachment further comprises a sidewall having an inner surface for channelling foodstuffs towards the tool plate working surface. 13. The attachment of claim 12 when dependent on claim 6, wherein the inner surface is arranged inwardly from the receiving element. 14. The attachment of claim 12 or 13, wherein the inner surface is smooth and featureless, and is preferably made of or coated with a low-friction material, preferably PTFE. 15. The attachment of any of claims 12 to 14, wherein the attachment is adapted to provide a clear path for foodstuffs on either side of the tool plate working surface within the inner surface. 16. The attachment of any preceding claim, wherein the attachment is adapted to interchangeably removably retain a plurality of tool plates, each tool plate having a different working surface for processing foodstuffs. 17. The attachment of any preceding claim, wherein the attachment further comprises one or more formations adapted, when the outer bowl is placed within a food processing bowl, to restrain rotational movement of the attachment relative to the food processing bowl. 18. The attachment of any preceding claim, further comprising a food processing bowl, wherein the attachment is configured to sit within an opening of the food processing bowl such that the tool plate is raised above a bottom of the food processing bowl for accommodating food processed through the tool plate. 19. The attachment of any preceding claim, further comprising a pressing tool configured to be attachable to a drive outlet of a food processing device to press food material towards the working surface of the tool plate; preferably wherein the pressing tool comprises rotatable resilient paddles for pushing food material towards the tool plate. 20. A tool plate for an attachment for a kitchen appliance, the attachment preferably being according to any of claims 1 to 19, the tool plate comprising: a working surface for processing foodstuffs, and one or more formations, preferably protrusions, for engagement with the attachment. 21. A combination, comprising at least two tool plates according to claim 20, each tool plate having matching formations for engagement with the attachment, preferably each tool plate having a different working surface for processing foodstuffs. 22. A kitchen appliance including the attachment of any preceding claim, the kitchen appliance preferably being either a stand-mixer or a bottom-driven food processor. 23. The kitchen appliance of claim 22, the kitchen appliance further comprising a heating element configured to heat food material pushed towards the tool plate; the kitchen appliance preferably further comprising a processor configured to control the heating of the heating element based on feedback from temperature sensors. 24. The kitchen appliance of any one of claims 22-23, including the attachment of claim 19, wherein the kitchen appliance further comprises a processor configured to control driving of the pressing tool based on sensed torque of the pressing tool. 25. A kit of parts comprising: the attachment of any of claims 1 to 19; and one or more tool plates, preferably of claim 20, each tool plate having a working surface for processing foodstuffs, and each tool plate being adapted for restraining by the attachment.