This invention relates to food mixers, by which is preferably meant the kind of motor- driven kitchen machine in which ingredients (preferably, such as foodstuffs), placed in a mixing bowl, are stirred, mixed or otherwise processed by means of a processing tool, and wherein the motor is used to create relative motion between the tool or tools and the bowl. Usually, the tool is moved within a stationary bowl, but in some arrangements the bowl is moved as well as, or instead of, the tool.

Such appliances 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 broad range of operations.

Recently, mixers with a still broader operational capability have been developed to incorporate heating means (such as a heater), enabling ingredients in the bowl to be heated whilst being subjected to the mixing/processing action. The degree of heating is usually selectable, allowing the ingredients to be completely cooked, partially cooked, or merely warmed, according to user requirements and/or the procedures dictated by individual recipes.

Whether or not heating facilities are provided in any given mixer, however, there is a need, especially with the trend towards smaller houses with correspondingly smaller kitchens, for the mixer as a whole to be compact, both for usage and for storage. Difficulties arise, however, in devising mixers that are compact whilst still possessing sufficient operating power and flexibility to meet the exacting needs of users.

The invention aims to address, at least in some part, the foregoing difficulties and, according to the invention, there is provided a food mixer comprising an electric motor, a bowl for ingredients, a tool for interacting with said ingredients to mix, stir or otherwise process them (preferably, including slicing and blending), and operating means (such as a drive mechanism or operating element) utilising the motor to cause relative movement between the tool and said ingredients, wherein said motor is provided with rotor and stator components configured into annular or dished form (preferably having the form of a pot); said motor being adapted to accommodate said bowl within said annulus or dish. By this means, the mixer is provided with compact dimensions and with a beneficially low centre of gravity, promoting good operational stability.

Preferably, the motor comprises a switched reluctance motor (sometimes known as a flux-switching motor) as such motors are capable of providing the operational speed and torque required whilst lending themselves to the required configuration of its stator and rotor components into the required dished or annular form.

In some preferred embodiments, the bowl is held stationary and is fitted with a driving arrangement configured to pick up drive from the rotor, and to engage with and drive said tool in rotation, preferably via the operating means. For compactness and in order for the bowl to be accommodated within the motor, preferably, the driving arrangement provides a rotary drive coupling through the base of the bowl.

In other preferred arrangements, the bowl is adapted to rotate with the rotor and, in such circumstances, means (preferably such as a restraint mechanism) may be provided for holding the tool stationary (and/or, preferably, by de-coupling the tool from the bowl, the rotor and/or the operating means) during such rotation of the bowl and rotor, in which case the tool may be mounted centrally of the bowl or it may be offset from the centre of the bowl, and/or angled relative to the base of the bowl. Because the bowl is preferably within said annulus or dish, it is safe for the bowl to be allowed to rotate.

Moreover, the tool is preferably located in place for operation of the mixer by engagement of co-operative means (or co-operative bearing) provided on the tool and a stationary lid provided to cover the bowl during use, preferably so that there is an upper bearing for the tool such that the tool may be operated in a stable manner.

For safety, preferably, latching means (such as a latch) are provided for securing the lid in place during operation of the mixer, and a safety interlock means (such as a safety interlock mechanism) is provided to prevent rotation of the tool, rotor and/or bowl unless the lid is secured in place so as to close the mixer. Alternatively, the tool may be mounted so as to rotate with the bowl and rotor, in which case, the rotor is preferably adapted to support, or constitute, an upright tubular wall of the processing bowl; in this way the bowl may act as a shaft through which foodstuffs may enter and processed foodstuffs may exit the device at different locations of the bowl. Because the bowl is preferably within said annulus or dish, it is safe for the bowl to be allowed to rotate.

Preferably, the tool, bowl and/or rotor are integrally formed with one another.

Preferably, in the embodiment just described, the stator and rotor are provided as annuli, and base means (or a base) are provided, preferably being attachable to the stator and forming a base part of said processing bowl and configured to allow processed ingredients to be removed from the base part of the mixer. Preferably, said base means and said stator are provided with co-operative latchable means (such as a latch) for latching the base means removable to the stator. Preferably, the mixer further comprises safety interlock means adapted to prevent rotation of the rotor unless the base means are secured in place. Preferably, the mixer further comprises support means adapted to support said mixer above a standing surface by a distance sufficient to permit removal of said ingredients from said base means and/or to accommodate a food collection bowl beneath said base part. Moreover, it is preferred to provide a lid for closing the mixer during use, to provide the lid with a feed-tube through which ingredients to be processed can be added, and/or preferably removed.

By this means, a "flow-through" configuration can be provided, whereby ingredients can be added through the feed tube and withdrawn through the base means. Foodstuffs can therefore be easily added to the bowl and processed foodstuffs can easily be removed from the bowl by the action of gravity, without having to scoop out the processed foodstuffs, dismantle the mixer and/or invert the bowl. In all embodiments of the invention, it is preferred to provide safety interlock means (or a safety interlock) whereby the rotor is prevented from rotating unless the mixer has been configured by the user into a safe operating condition, preferably wherein the lid and/or base means is latched to the stator and preferably the bowl, rotor and/or tool is securely restrained in the mixer.

According to another aspect of the invention, there is provided a kit of parts comprising: an electric motor; a bowl for ingredients; a tool for interacting with said ingredients to mix, stir or otherwise process them; and operating means utilising the motor to cause relative movement between the tool and said ingredients, wherein said motor is provided with rotor and stator components configured into annular or dished form; said motor being adapted to accommodate said bowl within said annulus or dish.

According to the invention from another aspect, there is provided a food processor or mixer comprising: a bowl for holding a foodstuff; and a motor for driving a tool for processing foodstuff within the bowl, the motor defining a space that is arranged to receive the bowl for processing the foodstuff. By providing a space suitable for the bowl to be received such that the tool may be operated to process ingredients within the bowl, a compact food processor is provided.

Preferably, the bowl and motor are arranged as, preferably substantially concentric, cylinders. Concentricity of the bowl and motor provides for a space-efficient food processor and further functionality, for example such that the bowl may be rotated within the motor. Preferably, the bowl is received within the motor so that the bowl and motor are coaxially arranged. Preferably, the term "cylinder" is herein used to refer to a tubular/annular cylinder and/or a cylinder comprising a bore through a portion of the height of the cylinder wherein the base geometry of the cylinders may be substantially circular or elliptical. Preferably, the motor comprises a stator and rotor, said space being defined by the stator and/or rotor.

Preferably, the bowl is arranged to receive the tool such that the tool, bowl and/or rotor are driven by the motor relative to the stator. According to another aspect of the invention, there is provided a food processor tool, bowl and/or motor for use in a food mixer as described with reference to the aforementioned food processor and/or food mixer.

The invention extends to a food mixer, a food processor and/or a kit of parts substantially as herein described and/or with reference to the accompanying drawings.

The invention also provides a computer program and a computer program product for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein, and a computer readable medium having stored thereon a program for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein. Any apparatus feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure, such as a suitably programmed processor and associated memory. Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa. Furthermore, any, some and/or all features in one aspect can be applied to any, some and/or all features in any other aspect, in any appropriate combination.

It should also be appreciated that particular combinations of the various features described and defined in any aspects of the invention can be implemented and/or supplied and/or used independently. In order that the invention may be clearly understood and readily carried into effect, three embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows, in exploded view, a mixer in accordance with one embodiment; Figure 2 shows the mixer of Figure 1 in cross-section;

Figure 3 is a plan view of the mixer shown in Figure 1 ;

Figure 4 shows, in exploded view, a mixer in accordance with a second embodiment;

Figure 5 shows the mixer of Figure 4 in cross-section; Figure 6 is a plan view of the mixer shown in Figure 4;

Figure 7 shows, in exploded view, a mixer in accordance with a third embodiment, this mixer being a variant of the second embodiment; Figure 8 shows the mixer of Figure 7 in cross-section; and

Figure 9 is a plan view of the mixer shown in Figure 7.

In all of the figures, similar components are indicated by the same reference numbers.

Referring now to Figures 1 to 3 of the drawings, Figure 1 in particular shows, in exploded view, the basic components of a food mixer (preferably, herein also referred to as a "food processor") 10 in accordance with one embodiment. In this example, the mixer 10 includes a stator 20 which is configured into a cup-like or bowl like form, or as an annulus, and also constitutes the main casing of the mixer. As will be explained in more detail with reference to later figures, the stator 20 is part of a switched reluctance motor (or more generally, preferably, any form of (AC or DC) stepper motor). The switched reluctance motor also includes a rotor 30, which is also formed into a cup-like, dish-like or pot-like shape, or an annulus, and nested within the stator 20. In this example, the rotor 30 is supported on bearings for rotation within the stator 20.

A bowl 40, in which ingredients can be mixed, stirred or otherwise processed, is configured to nest within the rotor 30 and to be held stationary therein; the components 20, 30 and 40 all being coaxially disposed, as shown. The bowl 40 is made of material approved for food contact, and is adapted for easy removal from the mixer 10 for washing. It is also preferably dishwasher proof.

A mixing or processing tool 50, in this example a bladed tool, is removably connectable to a driving unit 42 which is fixed into the base of the bowl 40 and configured to pick up rotary drive from the rotor 30 and convey the drive, through the base of the bowl 40, to rotate the bladed tool 50 within the bowl 40 about the vertically-oriented, common central axis of the bowl, stator and rotor. The arrangement of this driving unit 42 is typical of drive mechanisms well known and used for driving the processing blades within the goblet of a food processor. A lid 60 is used to close the mixer 10 when in use, and safety interlocking may be provided, in known manner, to prevent the motor from driving the bladed tool 50 unless the lid 60 is securely in place.

By these means, the bowl 40 of the food mixer is effectively accommodated within, or incorporated into, the switched-reluctance motor 20, 30. Switched reluctance motors are capable of delivering high power density at low cost, and incorporating the bowl 40 into the motor 20, 30 usefully reduces the overall size of the mixer 10; especially its height, without compromising its performance and functionality. In this example, the stator 20 comprises twelve stator winding poles, schematically shown at 21 in Figure 3, and the rotor 30 comprises four laminated ferromagnetic poles, schematically shown at 31 in Figure 3, but it will readily be appreciated that other arrangements and numbers of poles can be used without departing from the scope of the invention. The motor windings and ferromagnetic poles are of well-known construction, so will not be further described herein. The necessary switching control circuitry for sequentially energising the stator winding poles 21 to cause rotation of the rotor 30 is also well known and thus not further discussed herein.

When power is delivered, via the control circuitry, to the windings 21 of the stator 20, the rotor 30 rotates, about the central common axis of the mixer 10, on a bearing 22 supported centrally upon the base of the stator 20. The stator need not be formed with a closed or solid base, and if preferred, a spider-web-like arrangement comprising radial arms connecting a central hub that supports the bearing 22 to a circular rim, which may comprise a lower circular wall part of the stator 20, or may alternatively comprise a separate support for said lower circular wall part. In any event, the rotor 30 supports a downwardly-facing shaft 32 which runs in the bearing 22. The stator 20 and the rotor 30 are provided with co-operative upper bearing components 24 and 34 respectively; these bearings being designed to maintain concentricity of the rotor 30 during operation.

The in-bowl drive mechanism 42 is disposed in axial alignment with the food bowl 40 and the rotor bowl 30, and, as aforesaid, is designed to rotate independently about its axis, while the food bowl 40 is held stationary. The lower end of the in-bowl drive mechanism 42 has means 44 for engaging (such as an engaging formation or drive coupling) with a drive outlet 36 carried by the rotor 30 and thus for picking up drive directly from the rotor. The food bowl 40 is simply placed inside the rotor 30, ensuring that the drive coupling 44 engages properly with the drive outlet 36, and is latched in place for operation by the engagement of corresponding latch members 46 and 26 on the bowl and stator respectively. In this example, the components 46 and 26 constitute co-operative elements of a bayonet-type interlocking latch assembly, alternative latching techniques could be used if preferred. During machine operation, the food bowl 40 is held stationary, thus rotation of rotor 30 enables the in-bowl drive mechanism 42 to rotate the tool 50 relative to the bowl 40.

The upper end of the in-bowl drive mechanism 42 is provided with a shaft 48 configured to releasably engage into, and drive in rotation, any of a range of food processing and food mixing tools, thereby enabling a number of different food processing and/or mixing operations to be carried out within the food bowl 40. The upper end of the tool 50 has small shaft 52, extending upwards, which extends into, and runs freely in, a bearing arrangement 62 formed in the centre of the lid 60. The co-operation of components 48 and 62, together with a suitable latching arrangement (not shown) for holding the lid 60 securely in place on the stator 20, also operates to prevent the tool 50 from rising upwards during rotation. Furthermore, it maintains the tool concentricity during rotation.

As the food bowl 40 is removably placed inside the rotor 30, it can be easily removed for cleaning, simply by delatching the components 46 and 26. An optimum clearance is preferably maintained between the rotor 30 and food bowl 40, in order to avoid friction between them during operation of the mixer 10. Alternatively, or in addition, however, facing surfaces of the rotor 30 and bowl 40 can be formed of, or coated with, a wear- resistant and low-friction material.

Some preferred embodiments further provide means for heating the food bowl 40, enabling cooking or heating to occur as the ingredients are processed. In such circumstances, it will be appreciated that any convenient heating agency, such as infrared or microwave radiation, induction coil heat transfer, thermal conduction or convection and/or any other heating means may be utilised to produce the required heat for cooking the ingredients.

Some preferred embodiments are provided with means for varying the speed of operation of the motor (such as a controller for varying the speed of operation or circuitry for varying the voltage supplied to the motor), according to user requirement, and may also be provided with programmable means (such as a programmable controller) for defining one or more predetermined cycles of operation suited to different procedures.

In a second embodiment, shown in Figures 4 to 6, the arrangement is similar to the above-described first embodiment except insofar as the bowl 40 is configured to rotate with the rotor 30, and is thus nested therein and held for rotation by means such as the engagement of splines formed on the facing surfaces of the bowl 40 and rotor 30. In one alternative arrangement, co-operative drive elements can be formed in the bases of the rotor 30 and the bowl 40 as shown at 33 and 43 respectively in Figure 4. It is preferred to provide the stator 30 and bowl 40 as separate components, so that the bowl can be made of food-safe materials and can be removed separately for washing. In some embodiments, however, the rotor 30 and bowl 40 can be integrated into a single unit, with sleeving or mouldings provided if necessary to encapsulate the magnetic pole materials of the rotor.

During operation of the mixer 10, the food bowl 40 rotates, while the tool 54 is held stationary, thereby providing relative motion between the tool 54 and the ingredients in the food bowl 40. The tool 54 has a locating means 56 (such as a locating protrusion), which is formed to engage into a co-operative means 64 (such as a co-operating bearing for receiving the locating protrusion) provided centrally of the lid 60. The tool 54 is thereby locked in place by any known method and remains stationary during operation. In some embodiments, the tool such as 54 is not mounted centrally of the lid 60, but rather is mounted offset, so as to sweep a wider path through the ingredients in bowl 40, or the tool is mounted at an angle relative to the base of the bowl.

The tool 54 is shown in this example in the form of a K-Beater (a tool for beating or whisking comprising a K-shaped element), but it can take any form required to perform efficient mixing or processing of the ingredients in the bowl 40. In particular, the tool 54 may comprise a complex configuration designed to co-operate with the internal shape of the bowl 40 and to reach and interact with ingredients in any predetermined manner.

In a further embodiment, which is a variant of the second embodiment, and will now be described with reference to Figures 7 to 10 inclusive, the annular form of the mixer 10 is utilised in order to facilitate a "flow-through" arrangement, whereby ingredients can be added through the lid, processed in the bowl and then extracted from the base of the bowl.

In this embodiment, as stated, the annular form of the stator and rotor is used, whereby the stator 20 and the rotor 30 are both designed to be open at both top and bottom, thereby providing the user with the facility of direct serve, where the ingredients to be processed are added from the top and the processed ingredients are received at, and removable from, the bottom. When the power is delivered to the stator windings 21 of the stator 20, the rotor 30 rotates about its own axis as in the previous embodiment. As before, suitable means are provided between the stator 20 and the rotor 30 to maintain their concentricity (such as a co-operating bearing) and, in the present embodiment also, to prevent the rotor 30 falling from the stator 20 during operation of the mixer 10.

The rotor may contain a removable sleeve (not shown) which acts as the upright tubular wall of a food bowl, or the rotor annulus itself may be made of, or coated with, food-safe material, as indicated at 70, and thereby provide the upright tubular wall of the bowl in which the food ingredients are to be processed. In any event, the tubular wall such as 70 constituting part of a processing bowl is provided with means to accommodate (such as a coupling element) various food processing tools. For the purpose of illustration, a four-blade rotary slicing disc 72 is supported within the rotor/bowl 30, 70. The tool 72 is locked in place for operation so that, when the rotor/bowl 30, 70 rotates, the tool 72 also rotates along with it. It will be appreciated that the tool 72 is not limited to the shape and profile shown, and could be of any shape enabling the user to perform various food processing activities.

The top of the stator 20 has means such as circumferential latches 28 to accommodate a lid 60' which preferably, in this embodiment, has a feed-tube 66 provided therethrough in known manner through which ingredients to be processed can be added. In known manner, a pusher (not shown) can be provided, with which a user can push the ingredients down through the feed tube 66 and into contact with the blades of the tool 72. In well-known manner, the pusher and the feed tube 66 can be mutually designed to prevent the pusher from contacting the rotating tool 72. The lid 60' is further provided with a latching means 68 configured to co-operate with the latching means (or latch) 28 on the stator.

As before, safety interlocking is preferably provided, to ensure that the lid 60' is securely in place on the stator 20 before the motor can run. Moreover, particularly if the feed- tube 66 is one of large capacity, further interlocking may be provided such that the motor cannot run unless the pusher is engaged into the feed tube.

The bottom of the stator 20 is formed with attachment means (or an attachment mechanism) 29 capable of accepting the attachment of various food-extraction components forming, in effect, a base for the processing bowl and allowing or facilitating the extraction of processed foodstuffs from the rotor/bowl 30, 70. For purposes of illustration, a funnel attachment 80 is shown. The funnel attachment 80 is provided with latching components 82 to co-operate with the attachment means 29 to securely latch the funnel attachment 80 to the base of the stator 20 for operation of the mixer 10. Again, safety interlocking is preferably provided to ensure that the motor cannot be run without an attachment such as 80 in place. Typical alternative attachments to the funnel 80 are: colander and sieve attachments, milling attachments, a heated pan, a food collecting bowl, etc. It will be appreciated that, in this embodiment, the upright tubular wall 70 and the static base attachment 80 constitute, in effect, the processing bowl of the mixer 10, albeit that part of the bowl (70) rotates and part (80) is static during operation of the mixer.

The stator 20 is mounted on legs (not shown) to raise the mixer sufficiently far above a work-surface to allow the attachments such as 80 to be attached and detached as needed and, if necessary or if preferred, to accommodate a food-collecting bowl (not shown) beneath the attachment 80 for convenience.

Alternatives and modifications

It will be appreciated that the bowl 40 may itself be considered a tool for use in the mixer 10. For example, it is desirable in some cases to subject foodstuffs to a centrifugal force. For example, by providing perforations in the bowl, the bowl is available to be used to separate solids and fluids.

In yet a further alternative, there is a portion of the bowl 40 that protrudes from the motor when the bowl is nested within the motor 20 so as to ease dismantling of the mixer 10; this is balanced with the desire to provide a compact mixer by having the bowl fit (in its entirety) within the motor.

In another alternative, the rotor, bowl and/or tool may be integrally formed from one another for convenience.

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.