GB2435434A

GB2435434A - Improvements in or relating to stand mixer arrangements

Info

Publication number: GB2435434A
Application number: GB0603934A
Authority: GB
Inventors: Mark Seidler; Simon Clark
Original assignee: Kenwood Ltd
Current assignee: Kenwood Ltd
Priority date: 2006-02-28
Filing date: 2006-02-28
Publication date: 2007-08-29
Anticipated expiration: 2026-02-28
Also published as: GB0603934D0; GB2435434B

Abstract

A stand mixer having a mixing bowl 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 is provided with a heating capability for cooking or warming ingredients in the bowl. The invention provides user-operable timing controls for controlling interleaving and/or overlapping periods of heating and mixing, in accordance with user-selected programmes, for implementing food preparation procedures of varying degrees of complexity. Some of these programmes may, for example, be inadvisable for extended or unattended use of the stand mixer, and the invention may further detect user-selection of such programmes and control them by inhibition, or by the imposition of predetermined operational limits, unless any such control is deliberately over-ridden by the user.

Description

1 2435434

IMPROVEMENTS IN OR RELATING TO STAND MIXER

ARRANGEMENTS

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.

Such 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 drive outlets running at different speeds and with differing torque characteristics enabling them to perform a wide spread of operations.

Our co-pending UK patent application No. GB0602151.3, the disclosure of which is intended to be incorporated herein by reference, describes and claims stand mixer arrangements with a still broader operational capability; such arrangements including a mixer having 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 tools 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 invention in the aforesaid UK patent application encompasses the provision of any degree of heating; for example sufficient to completely cook, to partially cook, or to merely warm ingredients. It will be understood in this respect that the degree of heating is influenced both by the heater power (wattage) used in any given situation and the time for which the heat is applied.

Some such stand mixer arrangements are intended primarily for attended use, thus the heater power, which is normally adjustable, may conveniently be pre-set, or controlled by the user during a given heating process, and the time for which such heating is applied may again be pre-set, by means of an "end-of-cycle" timer, or determined ad hoc by the user. The power and timing control facilities necessary for such operations are similar to those provided for conventional cookery using a range, hob or oven.

The added operational facilities provided by stand mixer arrangements of the kind under consideration here, however, open up various more sophisticated possibilities for food preparation which place significantly higher demands upon the heating and timing controls used, and it is an object of this invention to address such demands.

According to the invention from one aspect there is provided a stand mixer arrangement including a mixer having 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 tools 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 comprising user-operable timing control means for controlling relative operational periods of said heating means and said drive system in accordance with user-selected programmes, means for detecting user-selection of at least one of said programmes having a predetermined characteristic, means pre-conditioning said stand mixer to inhibit operation of said at least one programme or to implement said at least one programme within predetermined control parameters.

Preferably, user-operable means permitting the application of said control parameters to be over-ridden are provided.

In a preferred embodiment, said at least one programme is a slow-cooking programme of duration greater than a predetermined time T. In a particularly preferred embodiment, the preconditioning means imposes a maximum operating power limit on said heating means.

Preferably, warning means are provided to advise the user of the inhibition of a selected programme, or the imposition of said control parameters thereon. The warning means can conveniently convey visual and/or audible warnings to the user.

Visual warnings may include textual or graphic messages conveyed to the user by means of a display, such as a liquid crystal display (LCD).

In some preferred embodiments of the invention, user-inputting of instructions for certain operational programmes is facilitated by pre-programming the microprocessor with a series of pre-determined operational sequences, any of which can be selected by the user pressing one of a plurality of special function keys, thereby causing the stand mixer to implement the desired operational programme without requiring the user to input all of the individual instructions with the interleaved timing required.

When the planetary mixing action is to be used intermittently during a cooking programme, it is preferred in some embodiments of the invention that the electric drive motor is operable in a "soft-start" mode, whereby the motor speed is increased in a controlled manner from a relatively low starting speed, in order to reduce the risk of splashing or otherwise ejecting hot ingredients out of the bowl or causing them to separate. This facility is user-selectable by means of a special key.

According to the invention from another aspect, the stand mixer of an arrangement as provided herein is further provided with a receiver for radio frequency (RF) control signals from a remote control handset (not shown) which permits the stand mixer to be instructed to perform, or be conditioned to perform, some at least of its functions remotely. In other embodiments, remote control signals for the stand mixer are input by means of a suitable device into the mains wiring and sent to the stand mixer over that wiring.

In some preferred embodiments, at least one of the stand mixer and the bowl further comprise said heating means. In other preferred embodiments, the heating means is separate from, but may be temporarily associated with, the stand mixer and the bowl.

In one preferred embodiment, the heating means is integral with the mixing bowl. In such circumstances, it is preferred that the heating means comprises an element encased against fluid ingress, so that the mixing bowl assembly can readily be cleaned, for example in a dishwasher.

In another preferred embodiment, the heating means is incorporated in the stand mixer, and in still another preferred embodiment, the heating means is provided separately from both the bowl and the stand mixer, and is interposable between the two when heating operations are required.

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.

Preferably, the bowl is formed so as to provide, at least in certain areas thereof, thermal insulation utilised to create relatively cool areas for handling. In this respect, the bowl may be formed with one or more handles extending outwardly from its upstanding wall; the bowl may be formed with multiple skins with air or another thermally insulative material in the gap between the skins; and/or the bowl may be formed with one or more areas of thermally insulative material.

The surface of the bowl may be coated or otherwise treated with a thermochromic material, which adopts a particular colour when hot, or which otherwise renders visible a warning message or logo, so as to warn users of areas which should not be handled.

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.

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: Figure 1 shows, in perspective view, a stand mixer in accordance with one example of the invention; Figure 2 shows the stand mixer of Figure 1 from a frontal elevation; Figure 3 shows a side elevation of the stand mixer of Figure 1; and Figure 4 shows one example of a bowl for use with the stand mixer; the bowl being shown in elevation in Figure 4a and in cross-sectional view in Figure 4b.

Referring now to Figures 1, 2 and 3, in which corresponding features carry the same reference numbers, a stand mixer 10 comprises a pedestal which supports a bowl platform 30 and a housing 40. The housing 40 encloses, in conventional fashion, an electric drive motor (not shown) and gearing (not shown) which conveys the motive power supplied by the motor 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, intended for food mixing, overhead of the bowl location, at 43, although it will readily be appreciated 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 44 of the outlet 43, 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 the central axis 45 of the outlet 43, 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, 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, and a suitable mechanism to permit the top 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.

A first example of an arrangement in accordance with the present invention will now be described with additional reference to Figure 4, which shows a bowl 60 configured and dimensioned to be received in the stand mixer 10 with its base 61 located in the recess 33 of the bowl platform 30. The base 61 of the bowl 60 is formed with a diametrically opposed pair of shaped slots, such as 62, respectively disposed and configured to co-operate with the latching elements 31, 32 of the stand mixer 10 to perform the aforementioned bayonet latching function.

As can be seen best in the cross-sectional view of Figure 4b, a heating element 71 is integrated into the base of the bowl 60. The heating element may be of any convenient kind, for example a sheathed resistance element or a thick-film heater, and it is secured to the underside of the bowl 60, in good thermally conductive relationship therewith, by any convenient means. Such heating elements are currently used, for example, in electric kettles and in domestic deep-fat fryers and any of the techniques used to fabricate and secure heating elements to vessels in such contexts may be utilised for stand mixer bowls.

The integral heating element 71 also has associated therewith, in this example, a thermostat device 74, and a suitable electrical connector 75 by way of which the bowl can pick up electrical power from a suitable outlet provided in the recess 33 of the bowl support 30. A thermal fuse (not shown) may also be provided in the base of the bowl 60.

It is preferred that an interlock is provided to prevent the energisation of the power outlet in the recess 33 unless the bowl 60 is in place. Indeed, an interlock may also prevent operation of the electrical drive motor of the stand mixer 10 unless the bowl is in place. In any event, it is still further preferred that the outlet comprises a female (socket) arrangement, rather than a male (plug) device. Conveniently, the connector 75 comprises spring-loaded, pin-like plug members that are compressed between the base 61 of the bowl 60 and the floor of the recess 33 until the bowl has been turned to the correct orientation and firmly latched in place by the bayonet fixtures such as 31, 32 and 62, whereupon the plug members can spring out to engage with the socket.

In an alternative embodiment, the recess 33 and the base of the bowl 60 are formed centrally and coaxially with the corresponding plug and socket elements of a 360 degree connector of the kind used with "cordless" electric kettles. In this embodiment, the bowl and the recess may be provided with screw attachment means or, if bayonet latches are provided, they may be located as shown in the drawing or alternatively they may be integrated with the coaxial plug and socket arrangement.

In the event that such a 360 degree connector as aforesaid is utilised, and in conjunction with a rotary latching system that provides at least a reasonable degree of rotation of the bowl 60 relative to the bowl support whilst retaining them in a suitably latched relationship, there can be advantage in utilising the technology described and claimed in our United Kingdom Patent No. GB 2328143-Bi, which permits different functionalities to be selected in dependence upon the relative orientation of the power base and the appliance. In the present context, for example, the bowl and the stand mixer can be configured to energise heaters of differing power when the bowl assumes selected orientations relative to the support 30, so that, for example, a very low wattage heater can be energised to provide a slow heating function when the bowl is in one orientation relative to the support 30, a substantially higher wattage heater can be energised for normal operation when the bowl assumes another angular orientation relative to the support 30, and the heaters are inoperative, providing conventional, cold mixing capability, when the bowl is in a third orientation relative to the support 30.

It will be appreciated that the low wattage heater may comprise a portion of the high wattage heater element, accessed via suitable tapping points.

It will also be appreciated that the lower wattage may be provided by cyclic interruption of the power to a single element.

In any event, the support 30 and the bowl 60 preferably carry co-operative graphics or other visual elements to assist a user in aligning them in their various locations.

In general, it is preferred that the bowl 60 is made of metal, and conforms to existing stand mixer design criteria, so as to be capable of using conventional mixing tools.

In this example, the bowl is formed so as to provide, at least in certain areas thereof, thermal insulation utilised to create relatively cool areas for handling. Optionally, the bowl may be formed with one or more insulated handles extending outwardly from its upstanding wall; the bowl may be formed with multiple skins with air or another thermally insulative material in the gap between the skins; and/or the bowl may be formed with one or more areas of thermally insulative material.

Alternatively, or in addition, the surface of the bowl, or at least such portions thereof as may be touched by a user, can usefully be coated or otherwise treated with a thermochromic material, which adopts a particular colour when hot, or which otherwise provides or renders visible a warning message or logo, so as to warn users of areas which should not be handled.

The bowl, 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.

The inner surface of the bowl is preferably coated, or otherwise provided, with non-stick material to guard against unwanted adherence of warmed or cooked ingredients thereto.

It is preferred that the bowl 60, once removed from the stand mixer 10, can be washed, for example in a dishwasher, without regard for the electrical components associated therewith, so it is preferred that the heating element is encased against liquid ingress; for example in a manner similar to that described (for the tank of a fryer) in our United Kingdom Patent No. GB 2255002-B 1.

Referring again to Figures 1, 2 and 3, it will be noted that the stand mixer is provided with a switch pad 85 presenting user-operable power controls and timer controls 90. The controls 80 and 90 comprise, in this example, digital controls interacting with a microprocessor (not shown) housed at any convenient location within the stand mixer housing.

Alternatively, the controls 80 and 90 may be analogue controls or one of them may use digital technology and the other analogue, depending upon design, cost and other criteria.

In this example, the power controls 80 provide control switches such as 81 to provide user-selected instructions to the microprocessor as to the heating power required and digital timing controls 90 provide control switches 91 for controlling timed operation of the motor-driven planetary drive of the stand mixer and control switches 92 for controlling timed operation of the heating element. The switches 91 and 92 are used to convey user instructions to the microprocessor and it will be appreciated that the processor may be configured to provide internal electronic interlocks to prevent certain combinations of instructions from being implemented. If an operation is prohibited, the user is warned by way of a lamp 100 and a warning buzzer which indicates that an inoperable or inadvisable combination of instructions has been inputted and that the user's operational strategy needs to be revised. In some embodiments of the invention, the warnings may be supplemented with, or replaced by, a visual display, such as a liquid crystal display (LCD) 86 used to convey textual and/or graphic instructions to the user. Associated with the display 86 are typical resetting and function control buttons 87.

The stand mixer 10 incorporates, in this example, a manually operable speed control adjuster 52 to enable the motor speed, and thus the speed at which the planetary mixing operation is driven, to be set by the user. In some other embodiments, the speed control function is digitised, and the controls therefore are incorporated into the switch pad 85.

Particularly where the stand mixer is set to implement a long cooking cycle, it needs to be borne in mind that the user's intention may be to leave the appliance unattended, for example whilst at work or whilst supervising children. This example of the invention therefore provides a safety provision, implemented under the control of an interlock program in the microprocessor, whereby when the timer is directly set to run the appliance in a heating mode for longer than a predetermined time, T, or the selection of an "auto-chef' function requires heating operations extending beyond the time T, operation of the heating power control automatically defaults to a low wattage "slow-safe" heating mode.

Engagement of this mode is indicated to the user by means of the lamp 100, or other visual display such as the LCD 86, and/or an audio indication, and, although operation in the "slow-safe" mode can be over-ridden by the user if necessary, such over-riding requires deliberate manual intervention. By this means, protection is provided against the eventuality of a user inadvertently leaving the appliance unattended whilst on a high wattage setting and with a long (slow-cook) cycle set up.

The timing controls 92 provide, in this example, the facility to operate the stand mixer with a delayed start and it may be determined that certain operational modes, even if requiring relatively short heating operations (i.e. enduring for times substantially less than T), if operated with a delayed start, might give rise to potential risk. In such eventualities, one or more "delay-safe" modes of operation can be imposed by the microprocessor, subject to the provision of warnings, as described above in relation to the "slow-safe" mode and the capability of manual over-ride if appropriate.

To facilitate the inputting of instructions when a complex operation is called for; say a long, slow cook with intermittent stirring, the microprocessor may be programmed with a series of pre-determined operational sequence programmes, any of which can be selected by the user pressing one of several "auto-chef' keys 95 which selects the appropriate operational sequence programme, thereby causing the stand mixer to implement the desired complex operational sequence without requiring the user to input all of the individual instructions with the interleaved timing required.

When the planetary mixing action is to be used intermittently during a cooking process, it is preferred in some embodiments of the invention that the electric drive motor is operable in a "soft-start" mode, whereby the motor speed is increased in a controlled manner from a relatively low starting speed, in order to reduce the risk of splashing or otherwise ejecting hot ingredients out of the bowl or causing them to separate. This facility is user-selectable by means of a special key 93, and is particularly desirable as the cooking process nears conclusion, since relatively high temperatures are then likely to prevail and moreover the ingredients are then likely to have softened and be generally of reduced viscosity, thus more likely to be splashed or otherwise ejected from the bowl.

In some embodiments, the stand mixer is provided with a receiver, for example in the form of an antenna formed on or coupled to a window 110 in the casing 20, for radio frequency (RF) control signals from a remote control handset (not shown) which permits the stand mixer to be instructed to perform, or be conditioned to perform, some at least of its functions remotely. In other embodiments, remote control signals for the stand mixer are input by means of a suitable device into the mains wiring and sent to the stand mixer over that wiring.

It will be appreciated that, in all embodiments of the invention, the heating means used can comprise any convenient technology. In this respect, it has previously been mentioned herein that the heating means may comprise a sheathed resistance element, a thick film heater or an inductive heater, for example, or combinations of these. In one particular embodiment, it is preferred to use one or more halogen lamp heating elements, for example of the kind used under ceramic cook-tops, comprising one or more halogen heat lamps mounted in a shallow tray of microporous thermally insulative material. Use of these heaters permits the use of non-metallic bowls.

In stead of the heater 71 being associated directly with the bowl 60, as shown in and described with reference to Figures 4a and 4b, other embodiments of the invention may, as described in more detail in the aforesaid UK patent application No. GB0602 151.3 a conventional bowl is provided in association with a heater which is either built into the stand mixer itself, and located beneath the floor of the recess 33 in the bowl platform 30, or which is fabricated into a heating pad arrangement which is separate from both the bowl 60 and the stand mixer 10, but which can be interposed between the two by placing it into the recess 30.

Claims

Claims: 1. A stand mixer arrangement including a mixer having 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 tools suspended into the bowl therefrom; the arrangement further comprising 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 comprising user-operable timing control means for controlling relative operational periods of said heating means and said drive system in accordance with user-selected programmes, means for detecting user-selection of at least one of said programmes having a predetermined characteristic, and function control means adapted to pre-condition said arrangement to inhibit operation of said at least one programme or to implement said at least one programme within predetermined control parameters.

2. An arrangement according to claim 1, further comprising user-operable means adapted to over-ride the pre-conditioning applied by said function control means.

3. An arrangement according to claim 1 or claim 2, wherein said at least one programme is a cooking programme of duration greater than a predetermined time T. 4. An arrangement according to claim 3, wherein the function control means is adapted to impose a maximum operating power limit on said heating means.

5. An arrangement according to any preceding claim, further comprising warning means configured to advise the user of the inhibition of a selected programme, or the imposition of said control parameters thereon.

6. An arrangement according to claim 5, wherein said warning means comprises display means to convey a visual warning to the user.

7. An arrangement according to claim 6 wherein said visual warning include textual or graphic messages conveyed to the user by means of said display means.

8. An arrangement according to claim 7, wherein said display means comprises a liquid crystal display (LCD).

9. An arrangement according to any of claims 5 to 8, wherein said warning means comprises means to convey an audible warning to the user.

10. An arrangement according to any preceding claim, wherein said timing control means includes a microprocessor.

11. An arrangement according to claim 10, wherein said microprocessor is pre-programmed with a series of pre-determined operational sequences, and wherein the arrangement further includes a set of special function keys, each adapted, when actuated by a user, to cause said arrangement to operate in accordance with a respective one of said pre-determined operational sequences.

12. An arrangement according to any preceding claim, further comprising means adapted to cause said motor to start up relatively slowly when actuated on at least one occasion during an operational sequence of the arrangement.

13. A stand mixer arrangement including a mixer having 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 tools suspended into the bowl therefrom; the arrangement further comprising 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 comprising user-operable timing control means for controlling relative operational periods of said heating means and said drive system in accordance with user-selected programmes, and wherein the stand mixer is further provided with a receiver for radio frequency (RF) control signals from a remote control handset (not shown) which permits the stand mixer to be instructed to perform, or be conditioned to perform, some at least of its functions remotely.

14. A stand mixer arrangement including a mixer having 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 tools suspended into the bowl therefrom; the arrangement further comprising 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 comprising user-operable timing control means for controlling relative operational periods of said heating means and said drive system in accordance with user-selected programmes, and wherein the stand mixer is further provided with means for receiving control signals transmitted thereto over mains wiring to which the mixer is connected and which signals permit the stand mixer to be instructed to perform, or be conditioned to perform, some at least of its functions remotely.

15. An arrangement according to any preceding claim, wherein said heating means is integral with said bowl.

16. An arrangement according to claim 15, wherein the heating means comprises an element encased against fluid ingress.

17. An arrangement according to any of claims 1 to 14, wherein said heating means is integral with said stand mixer.

18. An arrangement according to any of claims 1 to 14, wherein said heating means is separate from, but temporarily associatable with, the stand mixer and the bowl.

19. An arrangement according to any preceding claim, wherein said heating means comprises one or more of: a sheathed resistance element; a thick film heater; an inductive heater; and a halogen heating element.

20. A stand mixer arrangement substantially as herein described with reference to andlor as shown in the accompanying drawings.