Patent Publication Number: US-2022218154-A1

Title: Bowl assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. Ser. No. 16/079,618 filed Aug. 24, 2018, which is a 371 U.S. National Stage of International Application No. PCT/GB2017/050496, filed Feb. 24, 2017 and published in English as WO 2017/144907 A1 on Aug. 31, 2017. This application claims the benefit of Great Britain Application No. GB1603327.6, filed on Feb. 25, 2016. The disclosure of each of the above-identified applications is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a bowl assembly, for example for a kitchen appliance. In particular, this invention relates to a bowl assembly arranged to process contents such as food ingredients contained within the bowl assembly. 
     Technical Field 
     Kitchen appliances utilising a bowl containing a rotatable drive assembly to which a tool can be fitted are commonly used in the field of food preparation. Such kitchen appliances may also be arranged to heat the contents of the bowl. 
     Discussion 
     Certain cooking operations, such as slow cooking, rice cooking, and sous vide water bath cooking, do not require a rotating tool, and furthermore the presence of such a tool may impact the performance of these operations by obstructing movement of the ingredients and reducing the usable space in the bowl. A bowl containing a rotating drive assembly is therefore not well-suited to perform these and many other cooking operations. 
     According to an aspect of the invention there is provided a bowl assembly for an appliance such as a kitchen appliance arranged to process contents such as ingredients contained within the bowl assembly, comprising: a bowl having an aperture in its base; a tool mount for a food processing tool arranged to fit within the aperture; and a blanking plug arranged to fit within the aperture; wherein the tool mount and blanking plug are interchangeable with one another. 
     SUMMARY OF THE INVENTION 
     The tool mount and blanking plug may be each arranged to fill the aperture when fitted within the aperture, thereby sealing the aperture. Preferably, the tool mount and the blanking plug have substantially the same cross-sectional shape arranged to fit the aperture, whereby to seal it. Preferably, the cross-sectional shapes of both the tool mount and the blanking plug are arranged to correspond with the shape of the aperture such that they can fit the aperture, whereby to seal it. Preferably, by “fitting” the aperture the tool mount or blanking plug substantially fill the aperture. 
     The aperture may be a keyed aperture, and preferably has a non-circular shape. The tool mount and the blanking plug may each comprise a lip portion arranged to abut an edge of the aperture when fitted within the aperture. Preferably, the lip extends around substantially the entire circumference (or perimeter) of an upper (preferably a “cap”) portion. 
     The bowl assembly may further comprise a locking arrangement, wherein in a first configuration the tool mount may be releasably engaged with the locking arrangement whereby to secure the tool mount to the bowl; and in a second configuration the blanking plug may be releasably engaged with the locking arrangement whereby to secure the blanking plug to the bowl. 
     The locking arrangement may be provided by a separate locking member. Preferably, the locking member is arranged to engage with the tool mount or blanking plug from an underside of the bowl. The locking member may be arranged to pivot relative to the tool mount or blanking cap between a “locked” first position whereby the tool mount or blanking plug arrangement is held secure by the locking member and an “unlocked” second position whereby the tool mount or blanking plug is released by the locking member. Preferably, in the second position, the locking member is arranged to inhibit correct mounting of the bowl onto a base unit of a kitchen appliance. 
     The locking member may comprise a collar arranged to receive part of the tool mount or blanking plug and a handle element extending outwardly from the collar. The locking member may be arranged so as to inhibit correct mounting of the bowl assembly onto a kitchen appliance when the locking member is in the second position. Optionally, the locking arrangement may be integral with the bowl. The locking arrangement may be configured to inhibit movement of the tool mount or blanking plug static relative to the bowl when fitted within the aperture of the bowl. 
     The tool mount is preferably a drivable tool mount, for transmitting drive to a tool. 
     According to another aspect of the invention there is provided a bowl for a bowl assembly as herein described, wherein the bowl has an aperture shaped to inhibit rotation of the tool mount or blanking plug when fitted within the aperture. The aperture may be a keyed aperture. 
     The bowl may be arranged to supply heat to food ingredients contained within the bowl. Optionally, the bowl may comprise a heating element arranged in a base of the bowl. The heating element may be arranged to receive power from a kitchen appliance to which the bowl assembly is mounted. The heating element is preferably a resistive heating element. The heating element is preferably substantially annular or ring-shaped. Optionally, the bowl may be arranged to heat contents via induction, for example wherein the inductive source is a kitchen appliance to which the bowl assembly is mounted. Preferably, the bowl may be arranged to receive power and/or heat from a kitchen appliance or a base unit thereof. 
     A bowl support may be provided for supporting the bowl in an upright position. A heating element may be provided within the bowl support, arranged so as to heat the bowl and/or its contents. 
     According to another aspect of the invention there is provided a blanking plug for a bowl assembly as herein described, comprising a body portion and a cap portion, optionally wherein the cap portion is arranged to provide a substantially continuous inner surface in the bowl when the body portion is fitted within an aperture in the bowl. 
     The cap portion may be arranged to extend across the aperture in the bowl. The cap portion may comprise a material having a thermal conductivity that is substantially similar to the material of the inner surface of the bowl so as to ensure continuity of heat transfer across the inner surface of the bowl. 
     The cap portion may arranged to overhang the body so as to provide a lip that can rest on an edge of the aperture when the blanking plug is fitted within the aperture. Preferably, the lip extends substantially the circumference of the cap portion. Preferably, the lip extends a sufficient amount to allow a sealing member to be positioned between the lip and the edge of the aperture. Optionally, the blanking plug may comprise an integral sealing member provided on an underside of the lip so as to be positioned between the lip and the edge of the aperture when the blanking plug is fitted within the aperture. The sealing member may be more deformable than the lip of the cap portion, whereby to effect a fluid-tight seal in use. 
     The body portion may define a dog-leg shape such that a part of the body portion further from the cap portion has a cross-section of a smaller diameter than a part of the body portion closer to the cap portion. The blanking plug may further comprise a plurality of bayonet tabs capable of being engaged by a locking arrangement whereby to secure the blanking plug to the bowl. Preferably, the plurality of tabs are provided on the part of the body portion that is further from the cap portion, preferably proximate a bottom surface of said further part of the body portion. 
     The upper part of the body portion may comprise a multi-faceted shape being arranged to correspond with a multi-faceted shape of the aperture and the part of the body portion that is further from the cap portion may comprise a substantially circular cross-sectional shape, preferably having a narrower diameter so as to be able to pass through the aperture readily. 
     The blanking plug may comprise a sensor arranged to measure a parameter of the bowl or food ingredients contained therein, preferably temperature. Preferably, the blanking plug further comprises a transmitter arranged to transmit data relating to a measured parameter. 
     According to another aspect of the invention there is provided a drivable tool mount for a bowl assembly as herein described. The tool mount may comprise a body portion; a cap portion; and a shaft arranged to extend longitudinally through the body portion such that it passes through the cap portion, wherein the cap portion is arranged to extend across an aperture in the bowl. 
     The drivable tool mount may be arranged to receive rotational drive from an underside of the bowl when fitted within the aperture, preferably from a rotatable drive outlet of the kitchen appliance. A bearing arrangement may be provided within the body portion for supporting the shaft. 
     The cap portion may comprise a material having a thermal conductivity that substantially similar to the material of the inner surface of the bowl so as to ensure continuity of heat transfer across the inner surface of the bowl. The cap portion may be arranged to overhang the body so as to provide a lip that can rest on an edge of the aperture when the drivable tool mount is fitted within the aperture. Preferably, the lip extends substantially the circumference of the cap portion. Preferably, the lip extends a sufficient amount to allow a sealing member to be positioned between the lip and the edge of the aperture. Alternatively, the driveable tool mount may further comprise an integral sealing member provided on an underside of the lip so as to be positioned between the lip and the edge of the aperture when the drivable tool mount is fitted within the aperture. The sealing member may be more deformable than the lip of the cap portion, whereby to effect a fluid-tight seal in use. 
     The body portion may define a dog-leg shape such that a part of the body portion further from the cap portion has a cross-section of a smaller diameter than a part of the body portion closer to the cap portion. The driveable tool mount may further comprise a plurality of bayonet tabs capable of being engaged by a locking arrangement whereby to secure the blanking plug to the bowl. Preferably, the plurality of tabs are provided on the part of the body portion further from the cap portion, preferably proximate a bottom surface of the further part of the body portion. 
     The upper part of the body portion may comprise a multi-faceted shape being arranged to correspond with a multi-faceted shape of the aperture and the part of the body portion further from the cap portion may comprise a substantially circular cross-sectional shape. 
     The driveable tool mount may comprise a sensor arranged to measure a parameter of the bowl or food ingredients contained therein, preferably temperature. Preferably, the driveable tool mount further comprises a transmitter arranged to transmit data relating to a measured parameter. 
     According to another aspect of the invention there is provided a kit of parts for constructing a bowl assembly, comprising: a bowl having an aperture as described above; a blanking plug arranged to fit within the aperture as described above; and a tool mount arranged to fit within the aperture as described above; wherein the tool mount and the blanking plug are interchangeable with one another. 
     The kit of parts may further comprise a locking member configured releasably to engage the tool mount or the blanking plug whereby to seal the aperture in the bowl. The kit of parts may further comprise at least one tool arranged to be mounted on the drivable tool mount. 
     According to an aspect of the invention, there is provided a method of providing multi-functionality to a bowl assembly for a kitchen appliance; comprising the steps of: providing a bowl assembly as described herein; removing one of said tool mount or blanking plug from the aperture; and fitting the other of said tool mount or blanking plug into the aperture. 
     The bowl assembly may further comprise a locking arrangement configured to engage the tool mount or blanking plug when fitted within the aperture whereby to secure it to the bowl. 
     According to another aspect of the invention there is provided a bowl assembly, comprising a bowl having an aperture, as described herein; a blanking plug arranged to fit within the aperture, as described herein; and/or a tool mount arranged to fit within the aperture, as described herein. 
     According to another aspect of the invention, there is provided a bowl assembly for a kitchen appliance arranged to process ingredients contained within the bowl assembly, comprising: a bowl having an aperture in its base; a rotational bearing (or “(drivable) tool mount”) arranged to fit within the aperture for mounting a food processing tool; a blanking plug arranged to fit within the aperture; and a locking arrangement, wherein either in a first configuration, the rotational bearing is releasably engaged with the locking arrangement whereby to seal the aperture in the bowl; or in a second configuration, the blanking plug is releasably engaged with the locking arrangement whereby to seal the aperture in the bowl; wherein the rotational bearing and blanking plug are interchangeable with one another. 
     Preferably, the tool mount and blanking plug are each arranged to fill the aperture when fitted within the aperture, thereby sealing the aperture. Preferably, the tool mount and the blanking plug have substantially the same cross-sectional shape arranged to fill the aperture. Preferably, the cross-sectional shapes of both the tool mount and the blanking plug are arranged to correspond with the shape of the aperture such that they can fit within and fill the aperture. 
     The aperture may have a shape arranged to prevent rotation of the rotational bearing ((drivable) tool mount) or blanking plug when fitted therein. The aperture may be a keyed aperture, preferably wherein the rotational bearing (or (drivable) tool mount) and blanking plug are correspondingly shaped. 
     The locking arrangement may be integral with the bowl. Alternatively, the locking arrangement may be provided by a separate locking member. The locking member may be arranged to engage with the rotational bearing (or tool mount) or blanking plug from an underside of the bowl. The locking member may be arranged to pivot relative to the rotational bearing (or tool mount) or blanking cap between a “locked” first position whereby the rotational bearing (or tool mount) or blanking plug arrangement is held by the locking member and an “unlocked” second position whereby the rotational bearing (or tool mount) or blanking plug is released by the locking member. In the second position, the locking member may be arranged to inhibit correct mounting of the bowl onto a base unit of a kitchen appliance. 
     The locking member may further comprise a collar arranged to receive part of the rotational bearing (or tool mount) or blanking plug and a handle element extending outwardly from the collar. The locking member may be arranged so as to inhibit correct mounting of the bowl assembly onto a kitchen appliance when the locking member is in the second position. 
     As used herein, the terms ‘tool mount’ and ‘driveable tool mount’ preferably connote an assembly for mounting a rotatable tool, preferably a tool adapted for food processing, and preferably for transmitting rotational drive to that tool. The assembly may optionally have a rotatable shaft to which a tool may be mounted. Alternatively, the tool mount may be an integral part of a rotatable tool. The term may also be interchangeable with the terms ‘rotational drive’, ‘drive assembly’, ‘bearing assembly’, and “rotational bearing”, for example. 
     As used herein, the term ‘blanking plug’ preferably connotes a component or an assembly operable to plug/seal an aperture. Preferably, the blanking plug has a featureless upper surface (or “cap”). 
     The invention extends to methods and/or apparatus substantially as herein described and/or as illustrated with reference to the accompanying drawings. 
     The invention extends to any novel aspects or features described and/or illustrated herein. In addition, apparatus aspects may be applied to method 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. 
     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. 
     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. It will be appreciated that the processing of food may include the processing and/or blending of liquid items, and may also include the processing of solid food or ice items into a liquid form. 
     The invention described here may be used in any kitchen appliance and/or as a stand-alone 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., food processors). It may be implemented in heated and/or cooled machines. The invention may also be implemented in both hand-held (e.g., hand blenders) and table-top (e.g., blenders) 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, whether motor-driven or manually powered. 
     Aspects and embodiments of the invention are set out in the appended claims. These and other aspects and embodiments of the invention are also described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       At least one embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  shows a bowl assembly mounted on a base unit of a kitchen appliance; 
         FIG. 2 a    shows a bowl of the bowl assembly; 
         FIG. 2 b    shows a cutaway side view of the bowl in  FIG. 2   a;    
         FIG. 3  shows a cutaway view of bowl assembly components; 
         FIG. 4 a    shows a bowl assembly having a driveable tool mount and a tool fitted; 
         FIG. 4 b    shows a cutaway side view of the bowl assembly in  FIG. 4   a;    
         FIG. 5 a    shows a bowl assembly having a blanking plug fitted; 
         FIG. 5 b    shows a cutaway side view of the bowl assembly in  FIG. 5   a;    
         FIG. 6 a    shows an exploded perspective view of a blanking plug and locking arrangement; 
         FIG. 6 b    shows an exploded side view of the blanking plug and the locking arrangement; 
         FIG. 6 c    shows an underside view of the blanking plug in a disengaged position within the locking arrangement; and 
         FIG. 7  shows a bowl assembly separated from a base unit of a kitchen appliance. 
     
    
    
       FIG. 1  shows a bowl assembly  110  mounted on a base unit  130  of a kitchen appliance  100 . The bowl assembly  110  comprises a bowl  112  and certain other assembly components, as will be described later on. The bowl assembly  110  may be provided with a lid  111  to prevent egress of ingredients during food processing. The bowl assembly  110  is wholly removable from the base unit  130 , allowing for easy cleaning, tool changes, and loading or removal of food items for processing. 
       FIG. 2 a    shows the bowl  112  of the bowl assembly  110 . The bowl  112  comprises a bowl support  120  arranged on the bottom of the bowl  112 . The bowl support  120  is configured to engage with the base unit  130  when the bowl assembly  110  is mounted on the base unit  130 . The bowl  112  comprises a flat bottom surface  114  and a wall  117 . The bowl  112  is cylindrically shaped, so as to promote the even processing of ingredients. The bottom surface  114  comprises an aperture  115  which may sealingly receive a component, as will be described later on. The aperture  115  preferably has a non-circular shape and may additionally be keyed, so as to prevent the rotation of any components being received into the aperture  115 . The aperture  115  is preferably located in an indented section  116  of the bottom surface  114 . The indented section  116  is preferably circular in shape, and is preferably located centrally on the bottom surface  114 . 
       FIG. 2 b    shows a cutaway side view of the bowl  112 . The bowl support  120  preferably comprises an outer wall  122  extending from the bottom surface  114 , defining a chamber  124  beneath the bowl  112 . A plate  123  having an aperture  125  is provided within the chamber  124 . The aperture  125  is aligned with the aperture  115  provided in the bowl  112 . The bowl support  120  further comprises an inner wall  127  extending from the edge of the aperture  125  towards the bottom surface  114 . The aperture  125  is arranged to be of a larger diameter than the aperture  115 , such that at least a portion of the indented section  116  extends beyond the inner wall  127  and is not supported by the bowl support  120 . 
     The bowl support  120  holds a heating element  126  between the plate  123  and the bottom surface  114  of the bowl  112 . The heating element  126  may be attached to the plate by fasteners  129 , for example peg-shaped screws or fasteners that may extend into the heating element  126  to attach it to the plate  123 . The heating element is electrically powered and, preferably, also controlled by the base unit  130 , as discussed further on. The heating element  126  is preferably annular or ring-shaped so as to promote the even processing of ingredients, although other shapes may also be used, including star-shaped, square-shaped, or concentric rings, for example. Preferably, a resistive heating element  126  is used, being bonded to the bottom surface  114 , although other heating elements may be used, including thick-film heaters, inductive heating either integral to the bowl or induced by an element in the base unit  130 , and other heating means. The heating element  126  may comprise steel tubes containing resistive elements over-cast with aluminium. A sealing element  128  is preferably provided between the heating element  126 , the inner wall  127 , the plate  123 , and the bottom surface  114 , so as to prevent any fluid from contacting the heating element  128  and to locate the bowl support  120  relative to the heating element  126 . The sealing element  128  preferably comprises a heat resistant and relatively heat conductive material, for example, a heat resistant polymer such as silicone. 
       FIG. 3  shows a cutaway view of bowl assembly  110  components. The components which can be engaged to the bowl  112  comprise a tool mount  200  which may be drivable, a processing tool  230 , a blanking plug  300 , a ring-shaped sealing member  140 , and a locking arrangement  150 . The sealing element  140  may be an “O”-ring, for example, comprising a compressible (relative to the material of the blanking plug  300 ) material such as rubber, or a polymer, for example, that can provide a seal under compression. The driveable tool mount  200  and the blanking plug  300  are arranged to be interchangeable components, each of which (together with the seal  140 ) can be received in the aperture  115  and be sealingly engaged by the locking arrangement  150 . The locking arrangement  150  is shown as a separate component, but it can also be integral to the bowl and allowed to move to the extent that it can engage the driveable tool mount  200  or the blanking plug  300 . 
       FIG. 4 a    shows the bowl assembly  110  having the driveable tool mount  200  and a tool  230  fitted.  FIG. 4 b    shows a cutaway side view of the bowl assembly  110  having a driveable tool mount  200  and a tool  230  fitted. The driveable tool mount  200  comprises a cap  204  and a body  202  having a dog-leg shape such that upper and lower parts  202   a ,  202   b  are defined, with the lower part  202   b  being less wide (or having a smaller cross-section) than the upper part  202   a . At least a part of the transverse cross-sectional shape of upper part  202   a  of the body  202  is arranged to have the same cross-section as the aperture  115 , so that the driveable tool mount  200  may be securely received into the aperture  115 . The cap  204  is arranged to be wider than the rest of the body  202 , such that a flange  206  is defined which the ring-shaped seal  140  can be located against. The cap  204  is arranged to extend above the top of the body  204 , such that it protrudes into the bowl  112 . Preferably, the cap  204  extends into the bowl  112  no further than 10% of the height of the bowl  112  (preferably, less than roughly 20 mm in a typical cooking bowl). Alternatively, the cap  204  may be arranged to be flush with the bottom surface  114 . The body  202  further comprises a plurality of tabs  208  for engaging with the locking arrangement  150 , as will be described later on. 
     The driveable tool mount  200  is arranged to hold a rotatable shaft  220  to which a tool  230  is mountable. The shaft  220  extends longitudinally through the driveable tool mount  200  and out of apertures provided in the cap  204  and a bottom surface of the body  202 . A plurality of bearings  209  are provided within the body to support the shaft  220  and allow it to freely rotate. The interior surfaces of the upper and lower parts of the body  202   a ,  202   b  are substantially parallel to the shaft, so as to support the bearings  209 . The end of the shaft  220  adjacent the bottom surface of the driveable tool mount  200  is provided with features arranged to be engaged with a drive coupling, such as a gear  210 . 
     The processing tool  230  is removably mountable to the distal end of the rotatable shaft  220  in respect of the gear  210 . The processing tool  230  is preferably interchangeable with a plurality of other processing tools  230  being adapted for particular processing operations, such as cutting or stirring. A cutting tool  230  is shown in  FIG. 4 a   . A processing tool  230  may comprise a plurality of members or blades  232  and an elongate central section  234  arranged to fit around the shaft  220 . Preferably, the elongate central section  234  also fits over the shaft  220 . A faceted section  222  may be provided on the shaft, being arranged to cooperate with a corresponding faceted section  236  provided on the inside of the central section  234  to allow the processing tool  230  to fit onto the shaft  220  using a twist fit or a snap fit. Other attachment means may alternatively be used, such as a screw fitting. Alternatively, the processing tool  230  may be permanently attached to the shaft  220 , and the entire driveable tool mount  200  may be interchanged with other driveable tool mounts  200  having a different processing tool  230  in order to change the tool. The shaft  220  (and thereby the processing tool  230 ) is powered and controlled by the base unit  130 . 
     Where the driveable tool mount  200  is engaged with the bowl assembly  110 , the driveable tool mount  200  is received into the aperture  115  in the bowl  112  with the seal  140  being located against the flange  206 . The locking arrangement  150  is used to compress the seal  140  between the flange  206  and the indented portion  116  of the bottom surface  114 , sealing the aperture  115 . When engaged, the end of the shaft  220  having the gear  210  extends through the locking arrangement  150  into the chamber  124 , allowing the shaft  220  to be driven via the gear  210 . When disengaged, the locking arrangement  150 , seal  140 , and the driveable tool mount  200  can be wholly removed from the bowl assembly  110 , allowing for improved cleaning as well as allowing for interchangeable components to be used with the bowl assembly  110 . 
       FIG. 5 a    shows the bowl assembly  110  having a blanking plug  300  fitted.  FIG. 5 b    shows a cutaway side view of the bowl assembly  110  having a blanking plug  300  fitted. The blanking plug  300  comprises a cap  304  defining a flange  306  and a body  302  having a dog-leg shape such that upper and lower parts  302   a ,  302   b  are defined, with the lower part  302   b  being less wide (or having a smaller cross-section) than the upper part  302   a . The body  302  is arranged to have the same dimensions as the body  202  of the driveable tool mount  200 , so that the blanking plug  300  can be used interchangeably with the driveable tool mount  200 . The body  302  of the blanking plug  300  differs from the body  202  of the driveable tool mount  200  in that it does not comprise apertures for a shaft. The cap  304  comprises a featureless top surface being arranged to remain static relative to the bowl  112 . 
     The blanking plug  300  is engaged with the bowl assembly  110  as described with reference to the driveable tool mount  200 , with the same locking arrangement  150  being used in the same way. Optionally, the same seal  140  may be used. The blanking plug  300  does not comprise any of the interior features of the driveable tool mount  200 , such as the bearings  209 , and so may be hollow. 
     Unlike the driveable tool mount  200 , the blanking plug  300  does not hold a shaft  220 , so the engagement of the blacking plug  300  with the bowl increases the space available in the bowl. The increased space in the bowl  112  where the blanking plug  300  is engaged allows the bowl  112  to be used with the heating element  126  for cooking operations such as slow cooking, sous vide water bath cooking, poaching, stewing, rice cooking, braising and pot roasting without the shaft  220  and/or tool  230  causing obstructions. This allows large ingredients to be cooked using the kitchen appliance  100 , for example, a slow cooked joint of meat. Both the driveable tool mount  200  and the blanking plug  300  may seal the aperture  115 , so the bowl  112  is safely useable where either component is engaged. 
       FIG. 6 a    shows an exploded perspective view of the blanking plug  300  and the locking arrangement  150 .  FIG. 6 b    shows an exploded side view of the blanking plug  300  and the locking arrangement  150 . The locking arrangement  150  comprises a collar  152  and a handle  154 . The collar  152  is cylindrical in shape and is open at both ends to allow components to protrude through the collar  152 . The handle  154  preferably comprises a member being arranged to extend radially away from an end of the collar  152  and a finger grip  156  extending perpendicularly out of the member. 
       FIG. 6 c    shows an underside view of the blanking plug  300  in a disengaged position within the locking arrangement  150 . The locking arrangement  150  is arranged to engage with the driveable tool mount  200  or the blanking plug  300  via a bayonet fit. A plurality of tabs  208 ,  308  are provided on the driveable tool mount  200  and the blanking plug  300 , the tabs  208 ,  308  being arranged to cooperate with corresponding bayonet features provided within the collar  152 . The tabs  208 ,  308  are preferably provided on the lower part of the body  202   b ,  302   b  proximate the bottom surface of the driveable tool mount  200  or the blanking plug  300 . The corresponding bayonet features may comprise inwardly protruding features  159 , recesses  158  and/or sloped slots  157  provided in a wall of the collar  152 . Where inwardly protruding features  159  are provided, the smaller cross-section of the lower part of the body  202   b ,  302   b  may allow the tabs  208 ,  308  to be engaged with the inwardly protruding feature  159 , as  FIGS. 4 b  and 5 b    show. 
     Preferably, the bayonet features are arranged such that the handle  154  is rotated 90 degrees or more to fully engage the driveable tool mount  200  or the blanking plug  300  and seal the aperture  115 . The use of a bayonet fitting allows the locking arrangement  150  to be easily engaged and disengaged by a user using the handle  154 . 
       FIG. 7  shows the bowl assembly  110  separated from the base unit  130  of the kitchen appliance  100 . The driveable tool mount  200  is shown fitted to the bowl assembly  110 , with the locking arrangement  150  being shown in a disengaged position. The base unit  130  comprises a cavity  132  arranged to fit the bowl support  120 . The cavity  132  comprises a drive coupling  134  and a probe  136 , both of which extend upwardly from the base of the cavity  132  so as to protrude into the chamber  124  when the bowl assembly  110  is engaged with the base unit  130 . The cavity  132  may comprise a drain (not shown) arranged to direct liquid entering the cavity  132  from above out of the cavity  132 , with the aim of preventing or mitigating any damage caused by liquid leakage in the event that the bowl assembly  110  is used when the aperture  115  not sealed. The base unit  130  may also comprise an electronic processor having a user interface and an electronic data-store. The processor is arranged to control the heating element  126  and/or a motor in response to user inputs and according to stored control instructions. Alternatively, the base unit  130  may comprise a simple analogue control system or an integrated circuit using transistor logic in place of the processor. 
     When the driveable tool mount  200  is engaged with the bowl assembly  110  and the bowl assembly  110  is mounted to the base unit  130 , the drive coupling  134  is arranged to engage with the gear  210  so as to supply drive to the shaft  220 . When the blanking plug  300  is instead engaged with the bowl assembly  110  and the bowl assembly  110  is mounted to the base unit  130 , the base of the blanking plug  300  is spaced away from the drive coupling  134 . The drive coupling  134  therefore cannot interfere with the bowl assembly  110  when the blanking plug  300  is engaged with the bowl assembly  110 . 
     The probe  136  is arranged so as to protrude through an aperture (not shown) provided in the plate  123  when the bowl assembly  110  is mounted to the base unit  130 . The positions of the aperture and the probe  136  are arranged such that the handle  154  of the locking arrangement  150  covers the aperture where the locking arrangement  150  is not in a fully engaged position. The width of the handle  154  is preferably arranged such that the aperture is accessible only when the locking arrangement  150  is in a fully engaged position. The arrangement of the aperture for the probe, the probe  136 , and the locking arrangement  150  prevents the bowl assembly  110  from being engaged with the base unit  130  where the locking arrangement  150  is not fully engaged. This thereby provides a safety interlock preventing the bowl assembly  110  being operated without being the aperture  115  being sealed. 
     The probe  136  may optionally comprise a temperature sensor such as a thermocouple or a thermistor, and may be arranged to protrude through the aperture in the plate  123  to approach or contact the heating element  126 . 
     The bowl  112  preferably comprises a metal to improve heat transfer to ingredients during cooking. The bowl support  120  preferably comprises a relatively non-heat-conductive material such as plastic. At least the caps  204 ,  304  of the driveable tool mount  200  or the blanking plug  300  are preferably made out of a material with a thermal conductivity comparable to the material that the bowl  112  is made out of, so as to avoid a ‘cold spot’ being located at the cap  204 ,  304  during cooking. The material is preferably also food-safe, durable, and corrosion-resistant. Examples of such materials include metals such as stainless steel. 
     Preferably, a heat conductive path is provided from the heating element  126  to the cap  204 ,  304  to further mitigate the ‘cold spot’ effects of the cap  204 ,  304 . The heat conductive path is created by providing that at least some of the bowl  112 , the body  202 ,  302 , or the collar  152  comprise heat conductive materials, preferably metals in metal-to-metal contact. The handle  154  preferably comprises or is coated with an insulating material such as plastic, to facilitate a user manipulating the handle  154 . The seal  140  preferably comprises a flexible, heat-resistant and relatively conductive material, such as rubber. 
     Although the seal  140  has been described as a separate component, it will be appreciated that one or more sealing components  140  that are integral with the flanges  206 ,  306  or the indented section  116  could instead be used. 
     Instead of the recesses  158  and slots  157 , the locking arrangement  150  may alternatively be provided with a plurality of inwardly protruding tabs to provide a bayonet fitting with the tabs  208 ,  308 . It will be appreciated that a variety of methods of fitting the locking arrangement  150  and the driveable tool mount  200  or the blanking plug  300  together while compressing the seal  140  could be alternatively used, such as the driveable tool mount  200  or the blanking plug  300  being engaged via a sliding or rotational fit, such as a screw fit. It will also be appreciated that an alternative locking arrangement to the described collar  152  and handle  154  may be used to removably retain the driveable tool mount  200  or the blanking plug  300  in the aperture  115 , such as a locking lever. 
     The driveable tool mount  200  and the blanking plug  300  may comprise a body  202 ,  302  being made of a single component or alternatively multiple components. Where multiple components of the body  202 ,  302  are provided, a lower part  202   b ,  302   b  may be able to rotate independently from an upper part  202   a    302   a , so as to allow the aperture  115  to be locked by means of a bayonet fitting without frictional resistance between the flange  206 ,  306  and the seal  140  or the seal  140  and the indented section  116 . 
     The blanking plug  300  may comprise internal components, such as a sensor, such as a temperature sensor being arranged to measure temperature data related to the contents of the bowl, and a transmitter arranged to transmit said data. 
     Optionally, the blanking plug  300  may not be provided with a bottom surface, unlike the driveable tool mount  200 . Where the blanking plug  300  has no bottom surface, it may be provided with a plurality of graduation marks to allow the blanking plug  300  to be used as a measuring cup. 
     The bowl assembly  100  may be optionally provided with a further safety interlock mechanism, such as an electronic interlock mechanism. Where a further interlock mechanism is provided, the driveable tool mount  200  and/or the blanking plug  300  may be provided with tags being detectable by one or more sensors provided in the bowl assembly  110  or the base unit  130 . The further interlock mechanism may be configured to de-energise the drive coupling  134  where the blanking plug  300  is engaged with the bowl assembly  110 . The further interlock mechanism may also detect a tag provided in the lid  111 , and may be configured to allow activation of the heating element  126  without the presence of the lid  111  where the blanking plug  300  is engaged with the bowl assembly  100 , but not allow the same where the driveable tool mount  200  is engaged with the bowl assembly, because of the increased risk of splashing. The tags may communicate with the sensors using RFID, NFC, or magnetically-actuated reed switches, for example. Alternatively, the further interlock mechanism may be a physical mechanism comprising a push-rod and micro-switch arrangement, for example. In a further alternative, the further interlock mechanism may be used instead of the interlock mechanism provided by the arrangement of the locking arrangement  150 , probe  136 , and aperture for the probe. 
     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.