This invention relates to food processing equipment, such as liquidisers and blenders, and it relates more particularly, though not exclusively, to latching attachments, by means of which the processing is carried out, and to the free-standing base units of such equipment. Typically, the attachments comprise containers, such as goblets or bowls, in which the processing takes place, together with associated driven implements, such as bladed tools, which are moved, relative to material placed in the containers, in order to carry out the desired processing function. Typically also, the base units contain electric drive motors, to drive the implements, and operating and control circuitry and arrangements therefor. Food processing equipment typically utilises a rotational coupling fitment, such as screw threading or a bayonet fixture, to couple the container to the base unit. Typically also, the implement (usually a bladed implement) is rotated within the container by way of a shaft formed with a drive socket that docks with a complementary drive outlet on the base unit.

The rotational forces generated, particularly when the implement is set into rotation, can be quite significant and thus difficulties can arise whereby, if the implement is rotated in the opposite direction to the rotational coupling mechanism, there is a tendency for the container to become loosened in its fitment, or even decoupled from the base unit. Since there is an increasingly common requirement in food processing equipment for bi-directional rotation of the processing implement, and in particular for rapid and frequent reversals of the drive direction, this difficulty is exacerbated. It is an object of the invention to reduce the above-mentioned difficulty and, according to the invention from one aspect, there is provided a latching arrangement for food processing equipment; the said equipment comprising a food processing implement mounted for bi-directional rotation in a container and a base unit housing an electric motor and a drive outlet , powered by said motor, and a coupling for coupling said container to said base unit, the coupling requiring a coupling movement comprising rotation in one of said directions, such that the implement can be driven from said outlet; the arrangement further including a latch for latching said container to said base unit against a tendency for decoupling therefrom when the implement runs in the direction counter to that of the rotational coupling movement.

Preferably said latch is associated with a sensor for sensing the direction of rotation of said implement from time to time and for generating electrical control signals indicative of said direction.

Further preferably, a latching controller is provided for receiving said control signals and for developing electrical latching signals for application to said latch whereby said latch is effective only when said implement is rotated in the opposed direction to said rotational coupling. In some preferred embodiments, the latch comprises a solenoid arranged to move a locking lever between latching and unlatching positions in dependence upon the state of energisation of the solenoid coil. It is then further preferred that the locking lever is configured to engage, in its latching position, into a detent formed in the base of the container, thereby locking the container to the base unit, irrespective of the direction of rotation of an implement within the bowl.

It is preferred that the arrangement further includes a movement detector for detecting movement of said lever into said latching position and for responding to said detected movement to latch a lid to the container.

In some preferred embodiments, a digital motor is provided in said base unit to power said drive outlet means. Further preferably, the digital motor is capable of operating over a speed range extending from 50rpm to 13000rpm and provides sufficient torque to perform all required tasks without the need for a gearbox.

Some preferred embodiments further comprise electronic recognition circuitry provided in said base unit for recognising individual implements, and/or their containers, attached thereto, and for providing electrical recognition signals indicative of the identity of recognised implements and/or containers. In such circumstances, it is preferred that the arrangement further comprises either inhibitor control circuitry, responsive to said recognition signals and configured to inhibit processing operations inappropriate to a recognised implement and/or container, or selector control circuitry, responsive to said recognition signals and configured to automatically select processing functions appropriate for a recognised implement and/or container.

Preferred embodiments further comprise a microprocessor or microcontroller, housed in the powered base unit, for operating said drive outlet means in accordance with user instructions but subject to said instructions being appropriate for said implement and/or said container.

Some preferred embodiments further provide a display screen carried by said base unit and configured to display information pertinent to the operation and/or functionality of the food processor. In some preferred embodiments, there is provided a mechanical identification and speed- selecting arrangement wherein the bases of containers intended for different processing functions are constructed differently and wherein the base unit is provided with components configured to respond differently to the attachment of containers with the different base configurations.

In other preferred embodiments, each implement and/or each container 12 is fitted with an RFID tag and an associated sender/receiver is fitted into the powered base unit thereby permitting identification of the implement and/or its container by way of a digital signal received by the sender/ receiver in the power base from the tag upon attachment of the implement and/or container to the base unit, thereby enabling only appropriate operating programs to be automatically implemented and/or offered to the user.

The invention extends to a latching arrangement substantially as described with reference to and/or as shown in the accompanying drawings.

The invention extends to methods and/or apparatus substantially as herein described 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, a preferred embodiment 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 typical food processing appliance to which the invention may be applied; Figures 2(a) and 2(b) show cross-sectional views through the base of a container of a food processor to indicate the operation of a latching arrangement in accordance with one example;

Figure 3(a) shows a perspective view, and Figures 3(b) and 3(c) show cross-sectional views of the base of the container to illustrate an identification technique usable with the invention and capable of distinguishing between different containers attachable to a base unit; and

Figure 4 is a schematic block diagram indicating some basic electronic components usable in some embodiments. Food processors are versatile appliances, and are used in the kitchen for a wide variety of tasks, such as liquidising and blending, crushing ice cubes and general chopping or maceration of fruit and vegetables. Indeed, the range of tasks which the appliances are expected to perform is ever- expanding, particularly with increased awareness of exotic foods and healthy eating.

Referring now to the drawings, similar features in all of which are indicated by the same reference numbers, a typical food processor is shown at 10 in Figure 1. Such food processors are typically provided with processing implements, or tools (not shown), in the form of a bladed disc and/or a blade set, which may include a stack of blades, supported on a common spindle that sits upright in a food processing container 12, such as a bowl as shown, or a goblet, and is rotated, usually from beneath the container, about the axis of the spindle. The spindle of the blade set is driven through the base of the bowl, via a sealed coupling, from a drive outlet 52 (see Figure 4) provided on an exterior surface of a free-standing base unit 14 of the food processor; the base unit housing an electric motor 50 (see Figure 4) which can be activated in continuous or pulsed modes to spin the blade set as required to process foodstuffs in the bowl.

As will be explained in more detail with reference to Figure 4, the base unit 14 also houses electrical components and electronic circuitry to operate, and control the operations of, the electric motor 50, and presents user-operated control actuators 62, such as switches and the like, to permit users to actuate and select the operational speed etc. of the drive to the implement in the container 12. The base unit 14 also presents at least one drive outlet, shown schematically at 52 in Figure 4, with which the container 12 can dock when properly coupled to the base unit 14, in order to pick up the motor drive and transmit it to the implement in the container.

Considerable efforts have been made to improve the usefulness and efficiency of the implements used for processing, and one approach has been to provide such implements with blades which are shaped differently on their opposed edges, so that one blade edge is sharpened, for example, and the other edge is blunt. By this means, and subject to the drive being reversible, the implement can be used to perform different functions when rotated in opposing directions, or to perform complex processing functions by repeatedly alternating the direct of rotation of the tool in accordance with a predetermined program and/or by direct user intervention. Sometimes, however, bi-directional rotation is used with implements presenting identical blade edges in both directions, simply to achieve a chosen form of interaction with the materials being processed in the container. In any event, where bi-directionally rotated implements are employed, the invention provides latching means resisting and/or preventing accidental loosening or decoupling of the container 12 from the base unit 14 attributable to rotation of the implement in the opposed direction to the original coupling of the container to the base unit.

Referring now to Figures 2(a) and 2(b), a latching means 16 provided in accordance with one embodiment comprises a solenoid 18 arranged to move a locking lever 20 linearly back and forth along a runner system 22; the position of the lever 20 (extended or withdrawn) is determined, as is known, by the state of energisation of the solenoid coil 18. All parts of the latching means 16 are assembled into a pressing which fits into the top cover 24 (Figure 1) of the power base 14 of the appliance 10, and are effective to lock the container 12 into position on the base 14 when the solenoid coil 18 is activated to extend the lever 20. The lever 20 engages, when extended, into a detent (not shown) of any convenient form provided in the base moulding of the container 12, thereby locking the bowl 12 to the base 14, irrespective of the direction of rotation of an implement within the bowl.

The action of the lever 20 moving into its extended position can also, with advantage, be used, either directly via a mechanical coupling or indirectly, using a position sensor and electrical circuitry, to latch a lid 30 to the container 12. By this means, the lid 30 is locked only when the food processing implement is being rotated in the "reverse" direction (i.e. that tending to unlock the container 12 from the base 14), so providing the user with the convenience of being able to remove the lid 30 during rotation of the implement in the normal, or "forwards" direction.

The use of a device such as the solenoid 18 operated in the manner described, with the extended, locking, position of the latching lever 20 corresponding to energisation of the solenoid coil 18, ensures that the latch 16 is always disengaged in the event of a loss of electrical power to the base unit 14, thereby enabling a user to access the materials in the container 12. An alternative arrangement to locking the bowl lid 30 in response to the latching state of the container 12 to the base unit 14 can be provided by means of a mechanical latch system fitted to the bowl lid 30. In such an arrangement, the lid 30 is locked into place using a conventional interlock mechanism built into the bowl and released by depressing a button fitted into the lid.

The capability for bi-directional rotation of the implement in the bowl caters, as is known, for a number of possible processing procedures, and enables the implement to be worked with improved efficiency or with differing options for some at least of the tasks for which it is intended.

In order to further improve the performance of the implement, or the attachment as a whole, it is preferable for the motor 50 housed in the base unit 14 to be a digital motor. The use of such a motor permits accurate control of the rotational speed of the implement, as well as allowing the use of software controlled profiled operating programs, implemented in this example by means of a microcontroller such as that shown at 56 in Figure 4. Preferably, the motor is capable of operating over a wide speed range (for example from 50rpm to 13000rpm) and provides sufficient torque to perform all required tasks without the need for a gearbox, thereby simplifying the design and construction of the base unit 14, and providing scope for operation at reduced noise levels compared with geared systems. The use of a digital synchronous reluctance motor 50 is additionally beneficial in permitting the construction of base units 14 which are low and flat in profile, presenting a low centre of gravity which provides a stable operating platform for the food processor 10.

It is preferable, in order to take full advantage of the flexible operating regimes opened up by means of the invention, for the electronic circuitry provided in the base unit 14 to be capable of recognising individual implements, and/or their containers, coupled thereto, and to inhibit motor functions inappropriate to a recognised implement and/or container. By this means, implements can be prevented from running at inappropriate speeds, for example, or from being used in an inappropriate container. An alternative scenario is for the recognition of the implement and/or container to be used to automatically set the appliance up to operate in the intended mode.

Such arrangements are preferably operated under the control of the aforementioned microprocessor or microcontroller 56, housed in the powered base unit 14 of the appliance 10, which can accept inputs indicative of user instructions and the identities of tools or other accessories attached to the base unit, and ensure that appropriate drive speeds etc. are applied to the implements used in the various attachments.

Local screens, such as LCD screens 66, also linked to the microprocessor or microcontroller 56 may be provided, as indicated schematically in Figure 4, and be supported or mounted on the base unit 14 to display the state of functionality and to flag up various options or provide instructions, such as those advising against the selection of any operation which is inappropriate to the implement or container detected, and recommend alternative options. By way of example, the mechanical identification and speed- selecting arrangement illustrated in Figures 3(a), 3(b) and 3(c) can be employed, whereby the bases of containers such as 12 intended for different processing functions are constructed differently. This enables the different containers to be recognised because the base unit 14, to which they are fitted for use, contains components configured to respond differently to the attachment of containers with the different base configurations. In one example, two different base configurations are used; one for containers intended for use with high speed processing implements and the other for containers intended for use with slower- speed processing implements.

The arrangement is such that, when a high speed attachment is fitted to the power base 14, components associated with (or forming part of) a bayonet fixture for attaching the container to the powered base unit on the base of the container are arranged to engage with and move a lever system 32 from a first, rest position 34 (Figure 3(b)), against a spring 36, through an arcuate path to a second position 38 (Figure 3(c)) where the components actuate a micro switch 40. Actuation of the micro switch 40 indicates to the microcontroller 56 in the base unit 14 that user-selection of high speed processing operations is a valid procedure, and high speed motor drive ranges are thus enabled. It will be seen that the identity systems are duplicated in the arrangement shown in Figure 3, with the levers 32 of the two systems being diametrically opposed. This duplication is not essential, but its use provides a rugged and reliable arrangement and is preferred in practice. In any event, the bases of containers intended for lower speed implements are not fitted with the components that engage with the lever(s) 32, and thus the micro switch(es) 40 cannot be actuated and high speed operation is automatically inhibited. An alternative mechanical recognition procedure is based on that described in WO-A-2006/123094, wherein the bases of different containers are configured to engage with respective switching devices.

To differentiate between tools used within an attachment, where it may not be practical to use mechanical recognition, one option is the use of radio-frequency identification, or RFID, technology. In an RFID-based system, each implement and/or each container 12 is fitted with an RFID tag and an associated sender/receiver 68 (shown in dashed outline to indicate that it is an optional feature) is fitted into the powered base unit 14. When an attachment is fitted to the base unit, the sender/ receiver in the power base 14 receives a digital signal from the tag, and feeds the detected identity to the microprocessor or microcontroller 56, thereby enabling appropriate programs, or program choices, to be selected within the software. Alternative non-mechanical methods of implement/container recognition include bar code readers, optical sensors, weight sensors, magnetically activated reed switches, electrical contacts etc. As with the mechanical systems mentioned earlier, the non-mechanical systems, such as RFID, may be used not only to provide identification inputs for program functionality, but also, in conjunction with mechanical interlocks, as a safety check. Thus, by identifying the implement and/or container, it is possible to limit the maximum available speed to a safe value for any attachment that is fitted to the powered base.

As mentioned previously, in order to fully take advantage of the improved functionality offered by means of the invention, it is desirable for the powered base unit to incorporate a user interface display 66 which can be of any convenient size, shape and form to suit the design, shape and dimensions of the base unit 14 and displays to the user features such as program options and the running state of the appliance 10. The display 66 can conveniently also indicate the detected tool or attachment identity to the user as well as showing the weight of ingredients, a countdown timer, a count up timer, etc. and can carry indications advising/warning the user of selection of inappropriate functions or instances of automatic over-rides.

Selection buttons 62, conveniently located alongside the display 66, may be provided to allow choice of program function and other menu selections including countdown timer, weight unit of measure etc. The selection buttons can be of any kind, such as mechanical press-switches or capacitive touch sensors. Moreover, the user interface display 66 could be a TFT, OLED, LCD or any other type of screen. The display could be colour, monochrome or a combination of both. The appliance 10 may usefully be configured to operate in a so-called sleep mode, from which the user interface can be automatically re-started or initiated via a capacitive sensing unit, shown schematically at 64 in Figure 4, and activated by proximity of the user. Figure 4 shows, in schematic and block diagrammatic form, control circuitry for incorporation into the base unit 14 of an arrangement in accordance with one example.

In the example shown, a digital synchronous reluctance motor 50 is provided to power the drive outlet 52, to which an attachment such as 12 is coupled for use. The motor 50 is operated under the control of a motor control circuit 54 which itself is governed by a microcontroller 56.

Electrical power for the motor 50, the microcontroller 56 and any other component requiring it is supplied from the household mains electricity supply via a power cord 58, and by way of rectification and voltage changing circuits 60 as is well known.

The microcontroller 56 receives input signals and other operating data from various sources, such as the user interface panel 62, components, such as micro switch 40, of the implement/container identification circuitry, safety interlocking components, proximity sensor 64, RFID detector (if provided) and feedback from the motor control circuit 54, and uses these inputs to ensure that the appliance 10 is always operated consistently with the user settings, insofar as these are not inappropriate for the attachment for the time being in use.

In some embodiments, appropriate actions are inhibited. The user is advised of the inhibition by way of display panel 66 as mentioned above, which also provides guidance as to what should be done to achieve the intended processing function.

In other embodiments, the microcontroller 56 uses the various inputs to set the appliance 10 up for correct operation.

In any event, the microcontroller 56 is configured to provide the latching output signals to the solenoid 18 of the latching means 16, and to operate in a closed servo loop via the motor control circuit 54 and its feedback connection to provide close operational control over the selected operating program for the motor 50. 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.