GB2584607A

GB2584607A - Tool for a kitchen appliance

Info

Publication number: GB2584607A
Application number: GB1905981.5A
Authority: GB
Inventors: Lampard Bart
Original assignee: Kenwood Ltd
Current assignee: Kenwood Ltd
Priority date: 2019-04-29
Filing date: 2019-04-29
Publication date: 2020-12-16
Also published as: GB201905981D0

Abstract

A tool 100 for a kitchen appliance such as a food mixer that is detachably attached to the mixer (200, Fig 1B). The tool such as a whisk, beater or dough hook has a spacer formation 102 on the distal end of the tool, to space the working part 104 of the tool from a working surface 110 such as the surface of a mixing bowl/vessel 108. The spacer engages with the surface of the bowl and may be made from a different material to the working part, preferably wear resistant, non-marking and/or having a low friction thank the working tool. The spacer may have a circular cross-section wherein the distal end is rounded. Preferably the working surface of the bowl has a formation for receiving the spacer formation of the tool when in use, wherein the formation may be an annular groove that may be arranged to correspond with the path in the bowl of a planetary-geared tool. Preferably the tool is biased towards the working surface via a resilient member or spring within the tool mounting means in the head of the appliance.

Description

Tool for a kitchen appliance

Introduction

The present invention relates to a tool for a kitchen appliance, a bowl for a kitchen appliance, a kitchen appliance, and a corresponding system.

Background

Kitchen appliances, also known as kitchen machines, such as stand mixers are used to mix, beat, and otherwise process ingredients as part of food/beverage preparation. Stand mixers are typically provided with shanked tools, including whisks and beaters (collectively "mixing tools"), which are removably attachable to one or more rotary drive outlets of the stand mixer.

Summary of the invention

Aspects and embodiments of the present invention are set out in the appended claims. These and other aspects and embodiments of the invention are also described herein.

In an aspect, there is provided a tool for a kitchen appliance, comprising a spacer formation on a working part of the tool for spacing the working part from a surface This may allow the working part of the tool to be spaced apart from a surface (in particular a working surface of a kitchen appliance, such as the bottom of a bowl), which may thereby provide automatic height adjustment for the tool when the tool is forced towards or biased against the surface, improving performance.

The working part of the tool is the part of the tool which is designed to perform work on material which is processed by the kitchen appliance (using the tool). The working part may further be the part of the tool which, in use, is proximate a surface of a bowl of a kitchen appliance and/or approaches the surface of a bowl of a kitchen appliance. Performing work may comprises performing a particular function on, or imparting a particular property to, the material -such functions include cutting, stirring, kneading, and processing. The working part may comprise, for example, a blade, a loop of material (i.e. the part of a beater or whisk that extends at least partially radially from a tool shaft, and a hook, or at least part of any of the above.

The spacer formation (and optionally other parts of the tool) may be referred to as a non-working part of the tool, in that, in use, the spacer formation does not perform substantial work on, or impart substantial energy to, the material. In general the spacer formation is arranged such that the amount of energy imparted to the material when the tool is in use is minimised. The spacer formation may be arranged at an extremity of the tool.

The tool is generally a tool for operation in a bowl of a kitchen appliance, in particular a tool that operates best when spaced away from the bottom (or working surface) of the bowl. The tool is in particular configured to operate on liquid or semi-liquid material, such as a colloidal suspension, emulsion, solution, or aggregation. Particular examples of such material include pastes, doughs and foams.

The spacer formation preferably spaces the working part from the surface by contacting the surface. The spacer formation may be arranged on an axis of rotation of the tool, and may have a rotational symmetry about the axis of rotation. In use, the tool may rotate about an axis of rotation. Preferably, the spacer formation has a circular cross-section. For example, the spacer formation may be shaped generally or partially as a cylinder, cone, hemisphere, or sphere.

At least a major part of the spacer formation may be generally cylindrical in shape, in which case the spacer formation may have a diameter, at its greatest extent, of less than 2cm, preferably less than lcm; more preferably less than 0.5cm. The spacer formation may extend less than 1 cm from the working part; preferably less than 0.5cm; more preferably less than 0.2cm. The end of the spacer formation distal to the working part may be rounded, preferably such that the distal end is convex.

The spacer formation may be formed of a different material to the working part. The material is preferably wear resistant, low friction, and/or non-marking. The spacer formation may be formed of at least one of: Teflona; PEEK; Torlone; and an iguse material. Preferably, the spacer formation is formed of a material having a lower coefficient of friction with steel than the working part, so as to gain the advantages of higher-friction material in working food-matter whilst having a low-friction spacer. The spacer formation is alternatively formed of the same material as the working pad, preferably wherein the material is a metallic material.

The tool is preferably a rotary tool comprising a shaft. The tool may be one of: a whisk; a beater; and a dough hook.

Preferably, the tool is arranged for engagement with a drive of a kitchen appliance at a proximal end of the tool and the spacer formation is arranged at a distal end of the tool. The tool may comprise at least one engagement feature for engaging with a rotary drive of kitchen appliance.

In a further aspect, there is provided a tool for a kitchen appliance, comprising a spacer formation on a working pad of the tool, wherein the spacer formation is formed of a material having a lower coefficient of friction than the working part; optionally wherein the coefficient of friction is the coefficient of friction with steel.

In a further aspect, there is provided a kitchen appliance, comprising a tool as described herein; and a head unit for mounting the tool.

In a further aspect, there is provided a kitchen appliance, comprising a bowl having a working surface and a tool as described herein.

In a further aspect, there is provided a kitchen appliance, comprising: a container having a working surface; and a tool comprising: a working part; and a spacer formation on a working part of the tool for spacing the working pad from the working surface. The tool is preferably biased towards the working surface.

The working surface may comprise a formation which receives the spacer formation in use, preferably wherein the formation on the working surface is one of: a generally annular protrusion; and a generally annular groove. The formation on the working surface may be an annular groove arranged to correspond with the path in the bowl of a planetary-geared tool.

The kitchen appliance may further comprise a head unit for mounting the tool, preferably such that the tool is located within the container. The head unit may comprise means for biasing the tool towards the working surface; preferably in the form of a resilient member, or alternatively an angled keyway or spline configured to drive the tool towards the working surface under rotational load. The tool may be mounted to the head unit such that the tool can travel in a direction parallel to the or a shaft of the tool (and/or perpendicular to the working surface). The tool may be mounted at an oblique angle relative to the working surface.

In a further aspect, there is provided a bowl for a kitchen appliance, comprising a working surface having an annular formation for receiving, in use, a spacer formation of a tool, preferably wherein the formation on the working surface is one of: a generally annular protrusion; and a generally annular groove. The formation may be an annular groove arranged to correspond with the path in the bowl of a planetary-geared tool.

In a further aspect, there is provided a kitchen appliance as described herein and a bowl as described herein.

The tool (and/or the working part) may have a profile generally corresponding to the inner profile of the bowl, optionally wherein the spacer formation, in use, extends into a gap between the tool (and/or the working part) and the bowl.

In general, the performance of stand mixers (among other kitchen appliances) may depend heavily on the distance the tool is from the inside of the mixing bowl. Should this gap be too large then much of the ingredients are simply missed by the tool and so are not successfully incorporated into the mixture. This normally extends the time taken to fully mix the ingredients and may necessitate manual intervention from the user to improve the result of the processing. It can also be noted that the user's ability to mix small quantities of ingredients may also be limited by a large gap between the bottom of the mixing tool and mixing bowl.

Most stand mixers currently feature a method of tool height adjust, often in the form of a small adjustable nut that can be tightened or loosened to change the height of said tool. Although these features do currently exist, it is still understood that a lot of users are unaware of this feature and never utilise it. This may be to do with its subtle design, lack of information or simply no recognition of the impact it has on the mixing process.

These shortfalls result in lacklustre mixing results in some situations where a tool height adjustment would significantly benefit the end product, all because the users are not aware of the feature or think that they are unable to perform the adjustment themselves.

The need for manual adjustment tools is driven by the large tolerance stack from the tool itself, tool location component to the bowl location and the spun metal bowl itself To engineer and manufacture the product to hold tighter tolerances (to ultimately achieve better mixing performance) would add cost to the components involved.

The invention described herein may be used in any kitchen appliance and/or as a stand- alone device. This includes any domestic food-processing and/or preparation machine, including both top-driven machines (e.g., stand-mixers) and bottom-driven machines (e.g., food processors). It may be implemented in heated and/or cooled machines. The invention may also be implemented in both hand-held (e.g., hand blenders) and table- (e.g., blenders) machines. It may be used in a machine that is built-in to a work-top or work surface, or in a stand-alone device. The invention can also be provided as a stand-alone device, whether motor-driven or manually powered.

Whilst the invention has been described in the field of domestic food processing and preparation machines, it can also be implemented in any field of use where efficient, effective and convenient preparation and/or processing of material is desired, either on an industrial scale and/or in small amounts. The field of use includes the preparation and/or processing of: chemicals; pharmaceuticals; paints; building materials; clothing materials; agricultural and/or veterinary feeds and/or treatments, including fertilisers, grain and other agricultural and/or veterinary products; oils; fuels; dyes; cosmetics; plastics; tars; finishes; waxes; varnishes; beverages; medical and/or biological research materials; solders; alloys; effluent; and/or other substances. Any reference to "food", "beverage" (or similar language) herein may be replaced by such working mediums.

As used herein, the term "processing" preferably connotes any action relating to or contributing towards transforming products into foodstuff, or transforming foodstuff into a different form of foodstuff, including -as examples -applying mechanical work (e.g. for cutting, beating, blending, whisking, dicing, spiralising, grinding, extruding, shaping, kneading etc.) and applying heat or cold. "Food" and "foodstuff" as used herein can include beverages and frozen material and material used in creating them (e.g., coffee beans).

The invention extends to methods, system and apparatus substantially as herein described and/or as illustrated with reference to the accompanying figures.

Brief description of the figures

One or more aspects will now be described, by way of example only and with reference to the accompanying drawings having like-reference numerals, in which: Figure IA is a schematic side-on drawing showing the tool for the kitchen application according to an embodiment of the invention; Figure 1B is a schematic side-on drawing showing a stand-mixer head unit to which the tool can be attached; Figure 2A is a schematic side-on drawing of a planetary drive mechanism of a kitchen appliance configured to be used with the tool; Figure 2B is a schematic top view drawing of the planetary drive mechanism; and Figure 20 is a schematic top view drawing of the tool and bowl of a kitchen appliance with a planetary drive outlet.

Detailed description of the figures

Figure la shows a tool 100 having a working part 104 and a spacer formation 102 on the working part 104. The working part 104 of the tool 100 is the part of the tool that is configured to perform work on foodstuff -in other words, it is the actual operating part of the tool, rather than the part or parts of the tool which serve to support the tool (e.g. a shaft and any engagement features). The tool is shown suspended above a working surface 110, where the working part 104 of the tool 100 is spaced from the working surface 110 by the spacer formation 102 (which contacts the working surface 110 when the tool 100 is pressed against the working surface 110).

The working surface 110 is the inner surface of a bowl 108 for a kitchen appliance, such as a stand mixer. The bowl 108 is configured to contain the material that it is to be 35 worked on. The bowl 108 has dimensions such that at least a portion of the working part 104 of the tool 100 is able to sit within the container. In the illustrated embodiment the bowl 108 has a side wall that constrains the lateral movement of its contents such that they can remain proximate to the tool 100 when in use. Preferably the bowl 108 is made of steel, more preferably stainless steel due to its rust-resistance, and more preferably still stainless steel 304 as this grade is relatively malleable compared to other stainless steels making it easier to form. A mirror finish is preferably applied to at least an exterior of the bowl 108 to make it more attractive and easier to clean. Preferably an inner surface of the bowl 108 is surface-roughened by e.g., brushing, in order to promote frictional contact with food matter within the bowl 108 for, e.g., better kneading of dough.

The tool 100 is shown in contact with the inner surface 110 of the bowl 108 via the spacer formation 102. This enables the working part 104 of the tool 100 to be spaced from the working surface 110.

The tool 100 comprises a shaft 106 at at least a proximal end of the tool 100 with the spacer formation 102 being at a distal end of the tool 100, where the working part 104 is interposed between the shaft 106 and the spacer formation 102. The shaft 106 may alternatively extend through the tool such that the working part 104 surrounds the tool. The shaft 106 has engagement features such that it can engage with a drive mechanism. For example, the shaft 106 may be shanked. The tool 100 is removably attachable to a drive outlet of a kitchen appliance, such as a stand mixer, via the shaft 106 having shanked elements shaped so as to be received in a recess 206 of the drive outlet and held therein.

The tool 100 is a rotatable tool, with an axis of rotation A-A. In Figure la, the working part 104 of the tool 100 is a beater, but it will be appreciated that the present disclosure is relevant to other mixing tools and food processing tools. In particular, the tool may alternatively be a dough hook or whisk. All of these tools operate best on a mixture in a bowl when spaced from a bottom surface of a bowl. The radially extending portions of the working part 104 act to mix or process food in use. The working portion 104 of the tool may also comprise voids between the radially extending portions to facilitate the movement of the materials being worked on for improved mixing or processing performance.

The spacer formation 102 is on the working part 104 of the tool 100 and extends from the working part 104 of the tool 100 along the axis A-A. The spacer formation 102 is configured such that the amount of energy imparted by the spacer formation to the material when the tool is in use is less than that imparted by the working portion of the tool. As such, the spacer formation 102 has a smaller radial extent than the working part 104 of the tool 100, and generally has a circular cross-section. This allows for the spacer formation 102 to impart less work on the material in the bowl 108 than the working part of the tool 100. Preferably the spacer formation 102 has a small diameter, which at its greatest extent is less than 2 cm, preferably less than 1 cm; more preferably less than 0.5 cm.

The spacer formation 102 is configured so as to provide a small spacing between the bowl 108 and the working part 104 of the tool. The spacing used may differ between tools, but in general the spacer formation extends less than 1 cm from the working part 104 (along the axis A-A); preferably less than 0.5cm; more preferably less than 0.2 cm.

The spacer formation 102 can take a number of forms. In one example the distal part of the spacer formation 102 is rounded. An example of such a spacer formation is a bearing which might be provided on the distal end of the tool 100. The spacer formation 102 may alternatively, or in addition, have a major part that is cylindrical in shape. The part of the spacer formation 102 distal to the working part 104 of the tool 100, at which it will contact the working surface 110, may be rounded, or the point of contact might be substantially smaller in diameter that the major part of the spacer formation 102. For example, where the spacer formation comprises 102 a major part of a cylindrical shape the distal end of the spacer formation 102 may comprise a conical shape where, in use, the tool contacts the working surface at the point of the conical shape.

Providing a spacer formation 102 with a rounded or tapered distal portion may allow for a spacer formation 102 to contact the working surface 110 without significant friction between the spacer formation 102 and the working surface 110 in use. This provides for a low noise operation of the tool 100 and reduces wear and tear of the bowl 108, the working surface 110, the spacer formation 102 and the tool 100.

The spacer formation 102 is formed of a wear-resistant or low-friction material. These properties are often found in high performance plastics and ceramics. Preferably the material is one which will leave no residue or marking on the bowl material in use, and in contact with the working surface 110 will not be too noisy. Examples of appropriate materials are Teflon®, PEEK, TorIon®, and iguse engineering plastics. The spacer formation 102 is preferably formed of a material having a static coefficient of friction, dry or lubricated (whichever is greater), with steel of any given type (a material used for bowls in food processing and preparation machines such as stand mixers) of approximately 0.1 or less and more preferably 0.04 or less (i.e., the coefficient of friction of dry Teflon with steel). Steel is used here to define the coefficient of friction, its use here does not necessarily imply that the material contacting the spacer formation 102 must be steel.

Generally, the tool 100 itself (including the working part 104) is formed of a different material having properties better suited for processing, such as a metallic material. The tool 100 may be made of a material having a higher coefficient of friction with steel than that of the spacer formation 102, for gaining the advantages of materials having higher frictional contact (e.g., more closely wiping the sides of the bowl, retaining dough so as to knead it) whilst retaining the advantage of lower frictional contact in the spacer 102. For example, the tool 100 may have a static coefficient of friction with steel of 0.6 or greater (that of rubber with stainless steel 316). The tool 100 may, for example, be formed of one of steel, stainless steel, stainless steel 304 with a mirror-finish, aluminium, synthetic or natural rubber, or plastic. The spacer formation 102 may be formed around a protrusion on the working part 104 of the tool.

In an alternative, the working part 104 and the spacer formation 102 are formed of the same material, and may be formed from a single piece of material (for example in a casting process). In this case, the working surface 110 may be adapted to provide a quiet and low friction/wear interface between the working surface 110 and spacer formation 102. For example, the working surface 110 may comprise a low-friction portion (or "insert") against which the spacer formation will run in use. This may be a ring arranged along the axis A-A in use such that the ring receives the spacer formation 102.

Figure lb shows a head unit 200 of a stand mixer. The head unit 200 of a stand mixer is configured to rotatably drive the tool 100. The stand mixer head unit 200 comprises a drive outlet 202 to which a tool can be detachably attached. The drive outlet 202 is powered by a motor. The head unit 200 is configured such that the tool 100 may be mounted to the head unit 200, and the head unit 200 moved, such that the tool 100 is located in the container 108.

A bayonet 204 is provided on the drive outlet 202, into which the shanked portions of the tool 100 are configured to sit securely in use. The head unit 200 further comprises a recess 206 in which a portion of the drive outlet 202 is disposed. The motor is configured to drive the drive outlet 202 such that it rotates within the recess 206.

The drive outlet in the illustrated embodiment is a generally cylindrical drive outlet configured to sit within a generally cylindrical recess 206 of the head unit. The part 204 of the drive outlet configured to receive the tool 100 may protrude from the recess 206.

The recess 206 housing the drive outlet 202 is configured to allow the drive outlet 202 to travel in the direction of the axis of rotation of the drive outlet 202 (i.e. the drive outlet 202 can travel along its axis). The travel distance is limited such that the end of the drive outlet 202 inside the recess 206 cannot travel past the deepest portion of the recess 206 and the drive outlet 202 is configured such that it cannot entirely leave the recess 206. This allows for the height of the tool 100 (i.e. the distance of the tool 100 or the working part 104) to be varied.

The recess 206 is configured to provide a resilient force to resist the drive outlet 202 being forced deeper into the recess 206, i.e. to bias the working part 104 away from the head unit 200. In use, this force provides a bias to the tool in the direction of the working surface 108. In an example, the means for biasing the tool towards the working surface is provided by a spring 208 extending from the deepest portion of the recess towards the aperture of the recess 206 through which the drive outlet 202 protrudes.

In use, the tool 100 is engaged with the drive outlet 202 of the kitchen appliance, by means of the shanked portion of the tool and the corresponding features 204 of the drive outlet 202. The stand mixer 200 is rotated into a position such that the tool 100 is disposed pointing downwards within the mixing bowl 108 such that the spacer formation 102 contacts the inner surface 110 of the bowl 108, thereby spacing the working portion 104 of the tool 100 from the working surface 110. On contact of the spacer formation 102 with the surface 110 of the bowl 108, the drive outlet 202 will be urged further into the recess 206 of the head unit 200 of the stand mixer. This motion is resisted by the spring 208 disposed between the drive outlet 202 and the deepest part of the recess 206, thus providing a force which acts parallel to the axis of rotation A-A of the drive outlet 202 and tool 100 (i.e. the spring 208 acts to urge the drive outlet 202 away from the head unit 200). The spring 208 thus urges the tool 100 to maintain contact with the inside of the bowl 108 by means of the spacer formation 102. The drive outlet 202 is driven by the motor and imparts rotational motion to the tool 100. This rotational motion causes the working portion 104 of the tool 100 to perform work on the ingredients or materials contained within the bowl 108. The spacer formation 102 imparts far less energy or action to the ingredients, but maintains the distance of the working part 104 of the tool 102 from the mixing surface 110.

Referring to Figures 2A-C an optional planetary drive mechanism provided in the head unit 200 of a kitchen appliance is shown. The head unit is generally the same as the previously described head unit. The planetary drive mechanism is configured to impart a planetary motion to the tool 100. The planetary drive mechanism comprises a drive-in portion 210, the previously described drive outlet 202,a planetary carrier 212, a planetary gear 214, a ring gear 216 and a tool carrier.

The drive input mechanism 210 is disposed at the centre of a ring gear 216 and is rotatably driven by a motor. The planetary carrier 212 extends radially from the drive input 210 mechanism. At a distal end of the planetary carrier 212 a planetary gear 214 is disposed such that the planetary gear engages with the inner portion of the ring gear 216. The drive outlet 202 extends downwards from the planetary gear 214 on the axis of rotation C-C of the planetary gear. The distal end of the drive outlet 202 is configured to detachably attach to the tool 100. Thus, when the drive input 210 is driven to rotate by the motor, the planetary gear 212 orbits the drive outlet 202 and runs along the inner surface of the ring gear 216. The ring gear 216 is engaged with the planetary gear 212 which causes the planetary gear 212 to rotate about its centre and to rotate the drive out mechanism 202. With the tool 100 attached to the drive outlet 202 the tool 100 rotates about its axis of rotation C-C and orbits the axis of rotation B-B of the drive-in mechanism 210. The drive outlet 202 and tool 100 are configured to allow the tool to travel parallel to its axis of rotation when secured in the drive outlet 202.

With the tool 100 disposed in the drive outlet 202 and in use the path of the spacer formation 102 of the tool therefore traces a circle on the working surface 110 of the kitchen appliance. As previously described, the working surface 110 may comprise a low-friction insert 220 against which the spacer formation will run in use. This insert may be a large ring 220 having the diameter of the planetary orbit diameter whose centre is aligned with the centre of the drive-in mechanism on the axis B-B. The spacer formation 102 of the tool is configured to run inside the ruing 220. The width of the ring 220 is greater than the distal portion of the spacer formation 102 that is in contact with the ring 220. The ring 220 extends along the path traced by the spacer formation 102.

The drive outlet 202 generally comprises two pads: a male pad and a female part configured to engage with each other via a keyway, spline or other similar rotary location portion. The male part driven by the planetary gear and may be configured to impart rotary drive to the female part (or vice versa) while allowing an axial travel distance of the male and female parts relative to each other. In such an embodiment, the female part is configured to be attachable to the tool. The spline is low-friction so as to allow the axial movement of the male and female parts relative to each other under rotational load. This allows the tool 100 to travel parallel to the axis of rotation C-C. The spline may be formed of a low-friction material for the male and female parts of the drive outlet 202, alternatively or in addition the spline may be lubricated by a lubricant. A spring or resilient member can also be provided between the male and female parts of the drive outlet 202 to provide a force that resists the urging of the female part deeper into the male part (or vice versa) along their axis of rotation C-C. The travel distance of the female part is limited such that it cannot entirely leave the male part.

The nominal force or bias can be provided to the tool 100 in the direction of the working surface 110 in this embodiment by providing an angled or helical keyway or spline such that under rotational load the female part and the tool 100 are urged by the male part of the drive outlet 202 axially towards the working surface 110, in addition to their rotational motion. It will be appreciated that a keyway or spline arrangement can be provided for the drive outlet mechanism. It can also be appreciated that in such an alternative an angled or helical keyway or spline may be provided as an alternative to the spring 208, such that the tool 100 forms an oblique angle relative to the working surface 108. Such an angled keyway may also be applied to the previously described tool head 200.

Advantageously, by use of the described system, a user may not need to manually adjust tool height to an optimal level. The spacing between the working part 104 of the tool and the working surface 110 may be fixed by the spacer formation 102, where the bias causes the spacer formation 102 to remain in contact with the working surface 110. This may provide for improved processing of food, without the user having to manually adjust the kitchen appliance to the optimal distance for the particular tool 100 that is used as this is achieved automatically.

In an alternative, the head unit 200 used may not include a planetary drive, such that the tool does not move translationally in use. The head unit 200 described with reference to Figure lb may be used without a planetary drive.

It should 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.

Claims

Claims 1. A tool for a kitchen appliance, comprising a spacer formation on a working part of the tool for spacing the working part from a surface.
2. A tool according to Claim 1, wherein the spacer formation spaces the working part from the surface by contacting the surface
3. A tool according to Claim 1 or 2, wherein the spacer formation is arranged on an axis of rotation of the tool.
4. A tool according to Claim 3, wherein the spacer formation has a rotational symmetry about the axis of rotation.
5. A tool according to any preceding claim, wherein the spacer formation has a circular cross-section.
6. A tool according to any preceding claim, wherein at least a major part of the spacer formation is generally cylindrical in shape.
7. A tool according to Claim 5 or 6, wherein the spacer formation has a diameter, at its greatest extent, of less than 2cm, preferably less than 1cm; more preferably less than 0.5cm.
8 A tool according to any preceding claim, wherein the spacer formation extends less than 1cm from the working part; preferably less than 0.5cm; more preferably less than 0.2cm.
9. A tool according to any preceding claim, wherein the end of the spacer formation distal to the working part is rounded.
10. A tool according to any preceding claim wherein the spacer formation is formed of a different material to the working part, preferably wherein the spacer formation is formed of a material having a lower coefficient of friction with steel than the working part.
11. The tool according to any preceding claim, wherein the spacer formation is formed of at least one of: Teflon(); PEEK; Torlone; and an igus® material.
12. The tool according to any of Claims 1 to 9; wherein the spacer formation is formed of the same material as the working part, preferably wherein the material is a metallic material.
13.A tool according to any preceding claim, wherein the tool is a rotary tool comprising a shaft.
14.A tool according to any preceding claim where the tool is one of: a whisk. a beater; and a dough hook.
15.A tool according to any preceding claim, wherein the tool is arranged for engagement with a drive of a kitchen appliance at a proximal end of the tool and the spacer formation is arranged at a distal end of the tool.
16.A kitchen appliance comprising: a tool according to any preceding claim, and a head unit for mounting the tool
17. A kitchen appliance comprising: a bowl having a working surface and a tool according to any of Claims 1 to 15.
18. A kitchen appliance, comprising: a bowl having a working surface; and a tool comprising: a working part; and a spacer formation on a working part of the tool for spacing the working part from the working surface.
19.A kitchen appliance according to Claim 17 or 18, wherein the working surface comprises a formation which receives the spacer formation in use, preferably wherein the formation on the working surface is one of: a generally annular protrusion; and a generally annular groove.
20. A kitchen appliance according to any of Claims 17 to 19, further comprising a head unit for mounting the tool, preferably such that the tool is located within the container.
21. A kitchen appliance according to Claim 16 or 20 wherein the head unit comprises means for biasing the tool towards the working surface; preferably in the form of a resilient member.
22.A kitchen appliance according to any of Claims 16, 20 and 21, wherein the tool is mounted to the head unit such that the tool can travel in a direction parallel to the or a shaft of the tool.
23. A kitchen appliance according to any of Claims 16 and 20 to 22, wherein the tool is mounted at an oblique angle relative to the working surface.
24. A bowl for a kitchen appliance, comprising a working surface having an annular formation for receiving, in use, a spacer formation of a tool.
25. A system comprising a kitchen appliance according to Claim 16 and a bowl according to Claim 24.