Abstract:
A stand mixer ( 10 ) capable of subjecting ingredients in a bowl ( 60 ) to a planetary mixing action, and which is also provided with the capability of heating the ingredients, is further provided with a guarding device ( 70, 80 ) to reduce unwanted egress of steam and/or to prevent ingredients being ejected from the bowl ( 60 ). The guarding device comprises a first component ( 70 ) which is removably attachable to the stand mixer ( 10 ) in the vicinity of its planetary drive outlet ( 44 ) and a second component ( 80 ) which is removably attachable to the first component ( 70 ) and also to the bowl ( 60 ). The first component ( 70 ) is shaped and configured to shield part of the stand mixer ( 10 ) from heat and the second component ( 80 ) is designed to resist unwanted egress of steam and/or to prevent ingredients being ejected from the bowl. A user is thus provided with the flexibility of operating the stand mixer with just the first component ( 70 ) in place as a heat shield, thereby leaving the bowl ( 60 ) open so that steam can escape, or operating the stand mixer ( 10 ) with both components ( 70, 80 ) in place, in which case the bowl ( 60 ) is effectively covered.

Description:
FIELD OF THE INVENTION 
     This invention relates to arrangements including stand mixers, by which is meant the kind of kitchen machine in which a mixing bowl is supported on a pedestal which also supports an electric motor and a drive system including a drive outlet, overhead of the bowl, which permits a planetary mixing action to be imparted to tools suspended into the bowl from the overhead drive outlet. 
     BACKGROUND OF THE INVENTION 
     Stand mixers, such as the Kenwood Chef kitchen machine, are well known and have been well established in use for many years. Over the years, mixers of this kind have been adapted and developed so as to perform an ever broadening range of functions, and many such devices incorporate, for example, a plurality of selectively usable drive outlets capable of running at different speeds and having differing torque characteristics, thus enabling them to perform a wide spread of operations. 
     Recent technical developments have provided stand mixers with a still broader operational capability, as it has been proposed to incorporate heating arrangements into such machines, thereby to enable foodstuffs to be heated whilst being stirred or mixed by the normal planetary mixing action of the stand mixer. Of course, the heating arrangements can be used or not, according to user requirements, and it will also be appreciated that the heating temperature and the heating time are both controllable, enabling the user to apply any desired degree of heating; for example sufficient to completely cook, to partially cook, or to merely warm ingredients. 
     In preferred embodiments, the heating means is incorporated into the stand mixer, though it is possible for a heater to be incorporated into a bowl or other receptacle containing the ingredients, or for a heater to be incorporated into a heating pad which is separate from both the bowl and the stand mixer, but may be temporarily associated with them, for example by being interposed between the two, when required to perform a heating function. 
     SUMMARY OF THE INVENTION 
     In any event, it is desirable to provide a guarding device to reduce unwanted egress of steam and/or to prevent ingredients being ejected from the bowl or other receptacle in which they are being heated and/or stirred. Considerable demands are placed upon such guarding devices, and it is an object of this invention to provide a stand mixer with a guarding device capable of addressing several such demands. 
     According to the invention, there is provided a stand mixer arrangement including a pedestal for a mixing bowl; an electric motor and a drive system including a drive outlet disposed overhead of the bowl, capable of imparting a planetary mixing action to a tool suspended into the bowl therefrom; and heating means provided to permit, in accordance with user selection, ingredients in the bowl to be heated whilst being subjected to the planetary mixing action; the arrangement further including a guarding device for said bowl and wherein the guarding device comprises a first component removably attachable to the stand mixer in the vicinity of said drive outlet and surrounding said drive outlet and a second component removably attachable to the first component; said first component being adapted to shield part of the stand mixer from heat and said second component being adapted to resist unwanted egress of steam and/or to prevent ingredients being ejected from the bowl. By this means, the user is provided with the flexibility of having just the first component in place as a heat shield, leaving the bowl open so that steam can escape therefrom, or having both components in place, in which case the bowl is effectively covered. 
     Preferably the first component is shaped and dimensioned to provide an interference fit to a downwardly-dependant part of the stand mixer overlying the bowl. It is further preferred that the interference fit is augmented by a steam-resistant seal carried by the first component. 
     It is preferred that the second component is provided with a closable aperture through which ingredients may be added without the need to remove the second component, and it is further preferred, in some embodiments, that the second component is provided with a vent for the controlled egress of steam. 
     It is particularly preferred that the surface of the second component exposed to the bowl is configured to encourage condensate to flow back into the bowl. 
     The bowl may conveniently be made of metal, and may conform to existing stand mixer design and shape criteria, so as to be capable of using conventional mixing tools. 
     The bowl, or at least some part or parts thereof, may be constructed of a sandwich of materials in order to assist thermal transfer to the ingredients therein. For example, part at least of the bowl may be constructed with inner and outer stainless steel walls and/or base, with an interlayer of aluminium therebetween. 
     The stand mixer may be fitted with a scraping tool, attachable to its gearbox hub and constrained to revolve more slowly than the planetary-acting mixing tools; the scraping tool being configured to remove ingredients from the walls of the bowl in order to reduce the risk of burning or overheating of adherent materials. 
     The heating means may comprise a sheathed resistance element, a thick film heater, an inductive heater or a halogen heater, for example, or combinations of these. 
     It is preferred that an interlock is provided whereby the heating means is not energisable unless at least the first component of the guarding device is in place on the stand mixer. 
     The bowl may engage with the pedestal by means of a conventional screw or bayonet fixing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be clearly understood and readily carried into effect, certain embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which: 
         FIG. 1  shows, in perspective view, one example of a stand mixer suitable for use in the arrangement of the invention; 
         FIG. 2  shows the stand mixer of  FIG. 1  from a frontal elevation; 
         FIG. 3  shows, viewed on its underside, a heat guard formed as the first component of one example of an arrangement in accordance with the invention; 
         FIG. 4  shows the heat guard of  FIG. 3  in situ on a stand mixer; 
         FIG. 5   a  shows the heat guard of  FIGS. 3 and 4 , and  FIG. 5   b  shows a splash guard formed as the second component of one example of an arrangement in accordance with the invention; both components being viewed from above; 
         FIG. 6  shows the splash guard of  FIG. 5   b  from above; 
         FIG. 7  shows both components of the arrangement of  FIGS. 3 to 6  in situ on a stand mixer in the closed position, ready for use; and 
         FIG. 8  shows both components of the arrangement of  FIGS. 3 to 6  in situ on a stand mixer in the open position, ready to receive tools for stirring ingredients in the bowl of the stand mixer. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIGS. 1 and 2 , in which corresponding features carry the same reference numbers, a stand mixer  10  comprises a pedestal  20  which supports a bowl platform  30  and a housing  40 . The housing  40  encloses, either in an upright casing part  46  or in a header unit  48 , an electric drive motor and gearing (neither shown) which provides motive power to a plurality of drive outlets to which various tools can be attached to perform a wide variety of tasks in the kitchen. 
     In this particular example, there is provided a high-speed blender drive outlet behind covers  41 , a slow-speed mincer drive outlet behind cover  42  and a planetary drive outlet  44 , disposed beneath a gearbox casing  43 ; the planetary drive being intended for food mixing and thus being disposed overhead of the bowl location. It will readily be appreciated, however, that more, fewer and/or different drive outlets can be provided in accordance with desired functionality of the stand mixer. 
     A shanked mixing tool, attached as is conventional, to a socket comprised in the outlet  44 , will depend in use into a mixing bowl placed on the bowl platform  30 , and is configured to rotate about both the axis of the socket  44  and a central axis  45 , thus performing a planetary mixing action. The necessary relationships between the relative shapes and dimensions of the bowl and the mixing tool to ensure thorough and repeatable mixing of ingredients are well known and established in use over many years. 
     As shown in  FIGS. 1 and 2 , the stand mixer  10  is, in this example, provided with a pair of latches  31 ,  32  within a recess  33  provided in the bowl platform  30 , which latches co-operate with components on the base of the bowl to form a bayonet latching system which ensures firm and ready location of the bowl on its platform. Other latching systems, such as screw-threading for example, can be used as an alternative to bayonet latching if preferred. 
     The upright part  46  of the housing  40  is configured with a break line  47 , to permit the header part  48  of the stand mixer to be hinged away from the platform  30  end of the pedestal part  20 , in order to facilitate the insertion and removal of the mixing tools and the bowl. 
     The stand mixer  10  also incorporates electrical and mechanical user controls  51 ,  52  in conventional fashion. 
     In the pedestal  20 , beneath the bowl platform  30 , is provided a heating means (not shown) capable of generating sufficient heat to cook ingredients in the bowl. Typically, and indeed preferably, the bowl is of metal and the heating means comprises an inductive heater. Alternative or additional heating technologies can be employed, however, such as thick film heaters, halogen heaters and suitably configured sheathed resistance heaters. 
     If desired, the heating means may comprise relatively low and relatively high wattage settings, to enable the stand mixer arrangement to be used for slow cooking as well as for attended cooking programmes. It will be appreciated that, in such circumstances, the relatively low wattage setting may be provided by energising just a portion of a relatively high wattage heater element. Alternatively, the lower wattage may be provided by a separate element, or by cyclic interruption of the power to a single element. 
     In any event, the heating means typically has associated therewith a thermostat device and a thermal fuse (neither shown) which may communicate with the bowl in the manner described in our co-pending UK patent application No. GB0803325.0. 
     A first example of an arrangement in accordance with the present invention will now be described with additional reference to  FIGS. 3 to 8 , which show a two-component guarding device suitable for application to a stand mixer of the kind described with reference to  FIGS. 1 and 2 . It will be appreciated that, in use, a bowl  60  (see  FIGS. 4 ,  7  and  8 ) is received in the stand mixer  10  with its base located in the recess  33  of the bowl platform  30 . As previously mentioned, the base of the bowl  60  is formed with a diametrically opposed pair of shaped slots, respectively disposed and configured to co-operate with the latching elements  31 ,  32  of the stand mixer  10  to perform a bayonet latching function. 
     The bowl  60 , or at least selected parts thereof, such as the base and lower wall area, may be constructed of a sandwich of materials in order to assist thermal transfer to the ingredients therein. For example, the whole or selected parts of the bowl may be multi-skinned, with inner and outer stainless steel walls and/or base, and an interlayer of aluminium therebetween. 
     Referring now to  FIG. 3 , there is shown a view of a heat guard  70  which constitutes a first component of a guarding device for an arrangement in accordance with one example of the invention. In  FIG. 3 , the heat guard  70  is viewed on the side which, in use, would be its underside. 
     The heat guard  70  is typically moulded in transparent plastics material, such as polycarbonate, and comprises a body part  71  in which is formed an aperture  72  which is configured and contoured to provide an interference fit over the gearbox cover  43  of the stand mixer  10  shown in  FIGS. 1 and 2 , enabling the heat guard  70  to be firmly, but removably, attached to the stand mixer  10  merely by press-fitting the aperture  72  over the portion  43  of the stand mixer. As best seen in  FIG. 8 , the heat guard  70  surrounds the drive outlet  44 . A flexible seal, such as a rubber seal, may be interposed between the inner wall of the aperture  72  and the outer surface of the gearbox cover portion  43  in order to resist the passage of steam through the contact region between the aperture wall and the gearbox cover portion. Alternatively, a self-supporting rubber ring may be attached to the body part  71  to constitute both the aperture and the seal. 
     The body part  71  further supports an upstanding, U-shaped wall  73  which overlies the front of the stand mixer and curves around the front of the head portion  48  of the stand mixer  10  to protect, from heat, condensation and the possible ingress of steam, the head portion  48  of the stand mixer  10 , and the operational components, such as gearing components, housed therein. 
     The body part  71  is formed with further features to fulfil various functions, such as a relatively thin wall  74  around the aperture  72 , this wall depending downwards in normal use and providing, together with an in-turned portion leading to the aperture  72  itself, and the aforementioned seal, the necessary resilience to provide the degree of firmness required of the interference fit between the aperture  72  and the gearbox casing  43  of the stand mixer  10 . The rearwards-facing end of the body part  71  is formed with a lip  75  and an angled wall portion  76 ; the configuration of the lip  75  and the slope of the angled wall  76  being designed to encourage steam and condensate to return to the bowl  60 . 
     The periphery of the body part  71  is provided with a press-fitted resilient sealing strip  77 , which is removable for cleaning, but which is provided to form a seal between the heat guard  70  and a splash guard  80  (to be described in more detail hereinafter) which constitutes the second component of the guarding device provided in accordance with this embodiment of the invention. 
     Finally, the body part  71  is provided with latching features  78   a  and  78   b  to permit the aforesaid component  80  to be removably sealed and latched to the heat guard  70 . 
       FIG. 4  shows the heat guard  70  in situ, as for operation, on the stand mixer  10 . It will be appreciated that, if desired, the heat guard  70  can be used alone (i.e. without the splash guard  80 ) and  FIG. 4  shows that, with the first component (heat guard  70 ) in place, sufficient room is provided for steam to escape easily from the bowl  60 . Moreover, ready access to the bowl  60 , for example to add ingredients, is afforded when just the heat guard  70  is employed. 
     Although the entire range of operations of which the stand mixer  10  is capable, other than the heating function, can safely be used without the heat guard  70  in place, it is not recommended that any operation requiring the heating function is employed without the heat guard  70  in place. Accordingly, this embodiment of the invention provides a safety interlock which disables the heater unless the heat guard  70  is properly in place upon the stand mixer  10 . In this example, the interlock is provided by a magnetically operated reed switch (not shown) in the head portion  48  of the stand mixer  10 ; the switch responding to the presence of a magnet  79  (see  FIG. 5   a ) secured in any convenient manner to the body part  71 . The reed switch is used in known manner, either directly or indirectly, to interrupt the supply of electrical power to the heater unless the proximity of the magnet  79  is sensed thereby. 
       FIGS. 5   b  and  6  show the splash guard  80  which, as aforesaid, is designed to fit to the heat guard  70  and which constitutes the second component of the guarding device provided in accordance with this example of the invention. 
     The splash guard  80  is generally U-shaped, and typically formed of transparent plastics material, such as polycarbonate, and it is also formed with further features to fulfil various functions, such as a relatively flat rim portion  81  which is designed in use to sit upon the upper rim  61  of the bowl  60  to prevent ingredients being ejected from the bowl during the various cooking or cooking and stirring processes of which the stand mixer  10  is capable. 
     The splash guard  80  is also formed with a chute  82  which provides a generous opening to permit the addition of reasonably bulky ingredients during a cooking process; the chute  82  having associated therewith a cover or lid  83  which is hinged at  84  to the body of the splash guard  80 . The lid  83  can be raised by means of a handle  85 , which has a protective projection  86  strategically placed relative thereto and dimensioned to protect the user from steam issuing from the chute  82 . There may also be a steam exit vent  87  provided on the opposite side of the splash guard  80  to the chute  82 , though the provision of this vent is optional and it may thus be omitted if desired or preferred. 
     The splash guard itself can be manipulated by means of a fixed handle  88  which has a steam shield  89  associated therewith. The chute  82  is formed in an angled wall  90 , the angular disposition of which is designed to encourage condensate to return to the bowl  60 . The shape of the steam exit vent  87 , if provided, is also configured to encourage condensate to run back inside the bowl. 
     At the remote ends of the arms of its U-shaped form, the splash guard  80  is provided with features such as those shown at  91 , designed to engage and interfit with the latching features  78   a  and  78   b  formed on the body part  71  of the heat guard  70 , thereby temporarily latching the first and second components  70  and  80  together, with the sealing strip  77  between them for use, as shown in  FIGS. 7 and 8 . 
     In general it will be appreciated that the problem addressed by the present invention is that conventional (1-piece) splashguards do not provide the user with adequate control over the steam and condensation produced when used with a cooking stand mixer. In particular, conventional 1-piece splashguards do not adequately protect the stand mixer from steam and condensation. 
     In addressing this overall problem, it will be appreciated that a number of individual issues are specifically addressed. For example, the heat guard  70  protects the stand mixer  10  from the heat and moisture associated with steam rising from the bowl  60  which then condenses on the relatively cool stand mixer parts. Further, the heat guard  70  is interlocked, for example via the magnet  79  and associated reed-switch, to ensure that it is always fitted when any heating function is selected by the user. The magnet  79  can conveniently be retained within a cavity in the body part  71  by an elastomeric seal and ultrasonically welded plug. 
     In addition, the heat guard  70  is shaped and configured to encourage condensation to return to the bowl  60  and allows the user to manually wipe away excess condensation as required (when the splash guard  80  is not fitted). This significantly reduces the amount of condensation deposited outside the bowl  60  when the head of the stand mixer  10  is lifted. The heat guard  70  is retained onto the gearbox casing  43  of the stand mixer&#39;s gearbox by a press fit engagement, as with conventional splash guards, and is preferably sealed as described above. 
     Further, the heat guard  70  houses a press-fit retained elastomeric seal  77 , which provides a seal against the splash guard  80  when fitted, and is removable for cleaning. Further features on the heat guard  70  provide for simple latching to retain the splash guard. 
     The heat guard  70  may be used with or without the splash guard  80 . When used with the splash guard  80 , this is analogous to a saucepan being used with the lid. When used without the splash guard  80 , this is analogous to a saucepan being used without the lid. 
     The splash guard  80  is used only when the heat guard  70  is also fitted. The shape of the splash guard  80  encourages condensation to return to the bowl  60 . It incorporates a feed chute  82  with generous opening, a hinged latching feed chute lid  83  and features ( 89 ,  86 ) for protecting the user from hot steam when using handles ( 88  and  85 ) provided on the splash guard  80  and the chute lid  83  respectively. It also optionally contains the vent  87  which, if provided, is shaped to encourage condensation to return to the bowl  60 . The chute hinge  84  is designed to encourage condensation to return to the bowl  60 . 
     The main components  70  and  80  are typically fabricated by injection moulding with transparent colourless polycarbonate. The main seal, and magnet seal, are typically manufactured from silicone rubber. 
     Where both components  70  and  80  are used together, it may be preferred, as shown in  FIG. 8 , to so arrange the latching between them that the two components are retained together as the header unit  48  is raised away from the bowl platform  30 . Alternatively, however, it may be preferred to arrange that the splash guard  80  remains attached to the bowl  60  and that just the heat guard  70  is raised with the header unit  48 .