Patent Description:
Hair cutting devices, such as clippers or electric shavers, are widely used to cut body hair and typically include a handle and a cutting head. The cutting head usually comprises a movable inner cutting member which reciprocates with respect to an outer guard member to perform a cutting operation. The outer guard member comprises a main body and a plurality of guard teeth extending from the main body in side-by-side relationship, and the inner cutting member is provided with a plurality of blade teeth arranged in side-by-side relationship for cooperation with the guard teeth. In use, hairs that are received between adjacent guard teeth are cut by the inner cutting member with a scissor-like action.

In order to guide hairs to the cutting region, hair cutting devices are sometimes provided with a hair comb which lifts and guides hairs to the cutting region as the comb is moved over the skin. A hair comb typically comprises a base which attaches to the cutting device. Extending from the base are a plurality of comb teeth for guiding hairs to the cutting region. A comb tooth comprises a skin-contact surface for sliding along the skin of the user during a cutting stroke. On the opposite side of the comb tooth to the skin-contact surface is a guard-facing surface which faces the guard member when the comb is attached to the cutting device. When the comb is attached to the cutting device, the guard teeth abut the guard-facing surfaces to provide a predetermined spacing between the skin and the blade teeth in order to define a remaining length of the hairs after cutting (i.e. a hair cutting length).

<CIT> discloses a comb a for a hair cutting appliance. The comb comprising a comb piece that is arranged to be disposed at a skin-facing side of a stationary blade of a blade set, the comb piece comprising a plurality of comb teeth that define a cutting length of the blade set when the comb arrangement is mounted to the blade set. Further the comb piece comprises a flexure section that is arranged to urge a frontal portion of the comb piece against the skin-facing side of the stationary blade.

<CIT> discloses a hair comb according to the preamble of claim <NUM>.

A problem with such combs, however, is that the stiffness of the comb teeth is limited by the small geometric shape and volume that is necessary to adequately manipulate and guide hairs to the cutting region. The comb teeth are often flexible and can be displaced from their intended positions with respect to the guard teeth. For example, the comb teeth can displace laterally, in a direction along which the comb teeth are spaced apart. This not only lowers the overall robustness and quality of the hair comb, but also its ability to consistently and uniformly lift and guide hairs to the cutting region.

It would be advantageous to provide a hair comb for a hair cutting device which provides consistent improved hair lifting and guidance. It would also be desirable to provide a hair comb with increased robustness.

To better address one or more of the concerns above, in a first aspect of the invention, there is provided a hair comb for attaching to a cutting head of a hair-cutting device, the cutting head having an inner cutting member and an outer guard member comprising a main body and a plurality of guard teeth extending from the main body in side-by-side relationship. The hair comb comprises: a support body for attachment to the cutting head; and a plurality of comb teeth that extend longitudinally from the support body in side-by-side relationship. At least one (and in some embodiments each) comb tooth of the plurality of comb teeth comprises: a skin-contact surface and a guard-facing surface opposite the skin-contact surface, wherein the guard-facing surface has a depression which defines a space for receiving a distal end of a guard tooth when the hair comb is attached to the cutting head. The depression extends lengthwise in a longitudinal direction of the comb tooth. In this way, the depression restricts lateral movement of the comb tooth with respect to the guard tooth when the hair comb is attached to the cutting head. In addition, or alternatively, this arrangement prevents the distal end of the guard tooth from forming part of a hair guiding interface. When in use the hair comb is attached to the cutting head, or in other words: is in an engaged state, the guard tooth and the at least one comb tooth will have an outer profile which defines the hair guiding interface for directing hairs to the inner cutting member.

In a second aspect of the invention, there is provided a hair-cutting system, comprising: a hair-cutting device comprising a cutting head having an inner cutting member and an outer guard member, wherein the outer guard member comprises a main body and a plurality of guard teeth extending from the main body in side-by-side relationship; and a hair comb as described above in the preceding statement. The hair comb is configured to cooperate with the cutting head such that, when the hair comb is attached to the cutting head: at least a distal end of a guard tooth is received in the space defined by the depression on the guard-facing surface to engage the at least one comb tooth.

By receiving a distal end of a guard tooth in the space defined by the depression on the guard-facing surface of the comb tooth, the distal end will be bounded (in at least one direction) by comb tooth material (i.e. the sides of the depression) such that relative movement between the comb tooth and the guard tooth will be restricted, and in some embodiments prevented. There may be a gap between the guard tooth and one or more sides of the depression, in which case the comb tooth may be allowed to displace by a distance corresponding to the size of that gap, until one of the sides of the depression abuts the guard tooth to prevent further movement. In other embodiments, the guard tooth may be received snugly in the space between the two sides of the depression, to substantially prevent movement of the comb tooth relative the guard tooth when in the engaged state. In this way, the overall robustness and quality of the hair comb may be improved, and also its ability to consistently and uniformly lift and guide hairs to the cutting region.

Further, the Applicant has recognised that another problem with many hair combs is that hairs received between adjacent comb teeth can fall onto the guard-facing surfaces at a location that is forwards of the guard teeth in the direction of a hair cutting stroke, such that the distal ends of the guard teeth from the main body will collide with those hairs and cause them to be pushed away from the cutting region. In adjustable-length hair combs, where the comb teeth are able to translate with respect to the cutting head to adjust a hair cutting length, this problem is exacerbated because a larger area of the guard-facing surfaces may be exposed and, consequently, more hairs can be pushed out by collision with the guard teeth. This adversely affects the comb's ability to catch and transport hairs into the cutting spaces between guard teeth and correspondingly can lead to an uneven and incorrect hair length end result.

When in an engaged state, the guard tooth and the at least one comb tooth will have an outer profile which defines a hair guiding interface for directing hairs to the inner cutting member. However, by receiving the distal end of a guard tooth in the space defined by the surface depression on the guard-facing surface, the outer profile may be reduced as compared to hypothetical arrangements in which the guard-facing surface does not have a depression and the guard tooth simply rests on the guard-facing surface. The distal end of the guard tooth may have a height which is defined between an inner surface and an outer surface of the guard member and the depression may have a depth such that, when the hair comb is attached to the cutting head, at least some of the height of the distal end is received in the space defined by the depression and is prevented from forming part of the hair guiding interface.

The hair comb may be a single-piece hair comb which defines a fixed hair cutting length when attached to the cutting head. In other embodiments, the hair comb may be an adjustable length hair comb having two moveable parts. In that case, the hair comb may comprise: a first member for fixed attachment to the cutting head; and a second member which comprises the support body and the plurality of comb teeth; wherein the at least one comb tooth is wedge-shaped in that a height between the guard-facing surface and the skin-contact surface tapers towards a distal end of the at least one comb tooth from the support body; and wherein the second member is moveably connected to the first member to allow the comb teeth to translate with respect to the first member in a first direction; whereby, in use, translation of the comb teeth in the first direction causes the distal end of the at least one comb tooth to move forwards of the guard teeth in a cutting direction to adjust a spacing between a skin of a user and the inner cutting member in order to define a hair cutting length.

The depression may have any size or shape suitable for receiving and bounding a guard tooth. The guard-facing surface may have a depression comprising a groove. The groove may be a depression having two side walls that extend lengthwise and which define a space for receiving a guard tooth therebetween. The groove extends lengthwise in a longitudinal direction of the comb tooth. In this way, the groove (specifically the side walls) restricts lateral movement of the comb tooth.

The groove extends lengthwise in the first direction. Thismay help to restrict lateral movement of the comb tooth while allowing translation of the comb tooth to adjust a hair cutting length. It may in addition or alternatively help to hide the distal end of the guard tooth, to prevent the guard tooth forming part of the hair guiding interface, at multiple hair cutting length settings.

The depression may have a depth such that, when the hair comb is attached to the cutting head, at least <NUM>% of the height of the distal end may be received in the space defined by the depression and is prevented from forming part of the hair guiding interface.

The depression may have a lateral extent (e.g. between two sides thereof), in a direction along which the plurality of comb teeth are spaced apart, such that the guard tooth and the at least one comb tooth engage to restrict lateral movement of the comb tooth. This may further improve robustness of the hair comb, as the comb teeth tend to flex laterally. Further, by restricting lateral movement of the comb tooth, a uniform number of hairs may be distributed between adjacent comb teeth and thus guided to a cutting edge of the cutting device. This can improve the hair cutting result.

The lateral extent of the depression may be equal to a thickness of the guard tooth in the lateral direction. This may restrict lateral movement of the comb tooth to a greater extent.

A thickness of the guard tooth in a lateral direction, along which the guard teeth are spaced apart, may be tapered towards the distal end of the guard tooth. A lateral extent of the depression may taper towards a bottom of the depression. This may restrict lateral movement of the comb tooth to a greater extent.

The depression may have a V-shaped profile in cross-section. The depression may instead have a U-shaped profile in cross-section.

The hair comb may be configured to co-operate with the cutting head such that, when the hair comb is attached to the cutting head, at least the distal end of the guard tooth is inclined with respect to the guard-facing surface such that a distal tip of the guard tooth points towards the depression.

Referring to <FIG>, there is generally shown a hair cutting system <NUM> comprising a hair cutting device, which is in the form of a hair clipper <NUM>, and a hair comb <NUM>. Although the Figures show a hair clipper specifically, it will be appreciated that the invention is applicable more generally to any known type of cutting device having an inner cutting member and an outer guard member, such as an electric shaver.

Referring to <FIG> and <FIG>, which show the hair clipper <NUM> by itself, the hair clipper <NUM> comprises a clipper body having a cutting head <NUM> on which a cutting element <NUM> is attached and a handle portion <NUM> which generally extends away from the cutting head <NUM>. The clipper body is generally formed by a housing which forms the external surface of the clipper body.

The handle portion <NUM> is an elongate grippable portion by which a user can grip the clipper <NUM> with their hand during use. The handle portion <NUM> is partially covered with a rubberised or textured surface <NUM> to facilitate better gripping of the clipper <NUM> by a user, particularly when the handle portion <NUM> is wet. On a rear face of the handle portion <NUM> a power button <NUM> is provided for powering the clipper <NUM> on/off.

The cutting head <NUM> is arranged at an end of the handle portion <NUM>. The cutting head <NUM> comprises the cutting element <NUM> of the clipper <NUM>. The cutting element <NUM> comprises a movable inner cutting member <NUM> which reciprocates with respect to a static outer guard member <NUM> to perform a cutting operation. The outer guard member <NUM>, which may also be referred to as a stationary outer cutting member, comprises a main body <NUM> and a plurality of guard teeth <NUM> (which may themselves be bladed) extending from the main body <NUM> in side-by-side relationship, and the inner cutting member <NUM> is provided with a plurality of bladed teeth <NUM> arranged in side-by-side relationship for cooperation with the guard teeth <NUM>.

As best shown in <FIG>, the bladed teeth <NUM> and the guard teeth <NUM> combine to form a cutting edge <NUM> (as illustrated by the dashed line in <FIG>). The bladed teeth <NUM> are reciprocated laterally relative to the static guard teeth <NUM> in a direction parallel to the cutting edge <NUM>, such that hairs positioned between the guard teeth <NUM> are cut with a scissor-like action as the bladed teeth <NUM> move past the guard teeth <NUM>. The movable inner cutting member <NUM> may be reciprocated using a motor which powers a reciprocating mechanism (not shown) attached to the inner cutting member <NUM>. The motor may be powered by a rechargeable battery contained within the body of the clipper <NUM>. The motor can be selectively turned on and off using the power button <NUM>.

The cutting edge <NUM> forms a front edge of the cutting head <NUM>. A cutting direction x of the hair clipper <NUM> is normal to the cutting edge <NUM>. It should be understood that in order for hairs to easily enter the gaps between the guard teeth <NUM> and bladed teeth <NUM>, they must approach the cutting edge <NUM> from the front side of the cutting edge <NUM> parallel to the cutting direction x. Therefore, the hair clipper <NUM> cuts hair most effectively when moved forwards in the cutting direction x shown in <FIG>.

Returning to <FIG> and <FIG>, an outer surface <NUM> of the outer guard member <NUM> which is rearward of the cutting edge <NUM> in the cutting direction x faces the skin (not shown) in use. In use, for a close shave without a comb attached to the clipper <NUM>, the skin-facing outer surface <NUM> is generally pressed lightly against the user's skin, and the clipper <NUM> is slid along the user's skin in the cutting direction x, such that the cutting edge <NUM> moves forward along the user's skin in the cutting direction x, to cut any hairs that it encounters.

As best illustrated in <FIG>, the system <NUM> also comprises a comb <NUM>. The comb <NUM> guides and lifts hairs to be cut so that the cutting element <NUM> can cut them effectively and efficiently.

The comb <NUM> comprises a first member <NUM> and a second member <NUM>. The first member <NUM> comprises a body for fixedly attaching to the outer guard member <NUM> of the clipper <NUM>. To facilitate this, a connection feature in the form of a clip <NUM> extends from the rear of the body of the first member <NUM>. The clip <NUM> comprises a flexible or spring-loaded protrusion, an end of which is shaped to engage with a lip <NUM> at the rear of the outer guard member <NUM> to hold the first member <NUM> to the outer guard member <NUM> in a fixed arrangement. The clip <NUM> forms a snap-fit connection to the outer guard member <NUM>. The clip <NUM> further comprises a lever section <NUM> which can be pressed to undo the snap-fit and detach the first member <NUM> and thus the overall hair comb <NUM> from the outer guard member <NUM>. Other known types of connection features are also possible.

The second member <NUM> comprises a support body <NUM> which is moveably connected to the body of the first member <NUM>, to allow the second member <NUM> to translate with respect to the first member <NUM>, and thus the cutting edge <NUM> of the clipper <NUM> when the first member <NUM> is attached to the cutting head <NUM>. The second member <NUM> is configured to translate with respect to the first member <NUM> in a first direction <NUM> perpendicular to the cutting edge <NUM>.

As best shown in <FIG>, the second member <NUM> is configured to be moveably connected to the first member <NUM> in that it comprises two side elements <NUM> which run lengthwise in the first direction <NUM> on opposite, lateral sides of the support body <NUM>. A lateral extent between the side elements <NUM> is substantially equal to the width of the first member <NUM> in the lateral direction, such that the first member <NUM> is able to be received between, and slide along, the side elements <NUM> of the second member <NUM> in the first direction <NUM>. The first member <NUM> and the second member <NUM> may be movably connected via one or more rails incorporated into the first member <NUM> or the second member <NUM>, e.g. along the side elements <NUM>, or other mechanism which restricts relative movement to the first direction <NUM>. The first direction <NUM> is normal to the cutting edge <NUM> and is, in use, parallel to the outer surface <NUM> of the outer guard member <NUM>.

The support body <NUM> is a substantially continuous, e.g. planar, body having protrusions extending therefrom to form a plurality of comb teeth <NUM>. Each one of the plurality of comb teeth <NUM> extends longitudinally from the support body <NUM> to a distal end <NUM> of the comb tooth <NUM> which is furthest from the support body <NUM> in the first direction and, in use, the cutting direction x. The comb teeth <NUM> are arranged in side-by-side relationship and are spaced apart along a lateral direction parallel to the cutting edge <NUM>.

It will be appreciated that although the drawings show the comb teeth <NUM> extending from a substantially continuous and planar support body <NUM>, this is not required. The support body <NUM> may be formed by strips that extend from a rear connecting bar in the cutting direction x, for example. Indeed, the hair comb <NUM> may have any shape or structure which is suitable for attachment to the cutting head <NUM> of the hair clipper <NUM> and which generally defines a plurality of comb teeth <NUM>.

As best shown in <FIG>, the comb teeth <NUM> generally extend in parallel directions substantially perpendicularly to the cutting edge <NUM> away from the support body <NUM> and towards the surface of the skin on which hairs to be cut are located. The comb teeth <NUM> extend forward of the guard teeth <NUM> and the housing of the clipper <NUM> in the cutting direction x and the first direction <NUM>. Each one of the comb teeth <NUM> has a guard-facing surface <NUM> that extends at an obtuse angle, which is around <NUM> degrees, from a forward face <NUM> of the cutting head <NUM>. During translation of the second member <NUM> relative the first member <NUM>, the guard-facing surfaces <NUM> of the comb teeth <NUM> slide along the guard teeth <NUM>, although contact between them is not necessary. Each one of the comb teeth <NUM> also has a skin-contact surface <NUM> opposite the guard-facing surface <NUM>, where the skin contact surface <NUM> is for contacting and sliding along the skin of the user during a cutting stroke along cutting direction x.

The comb teeth <NUM> provide a predetermined spacing <NUM> between the skin of a user and the cutting edge <NUM> in order to define a hair cutting length, i.e. the length of the hairs after cutting. Further, the comb teeth <NUM> are substantially wedge shaped in that the height between the guard-facing surfaces <NUM> and the skin-contact surfaces <NUM> tapers towards the distal ends <NUM> of the comb teeth <NUM>. Accordingly, during translation of the second member <NUM> along the first direction <NUM>, the distal ends <NUM> of the comb teeth <NUM> move forwards of the guard teeth <NUM> and thus the cutting edge <NUM> in the cutting direction x, which is a horizontal direction parallel to the skin surface, to adjust the predetermined spacing <NUM> and thus the cutting length.

The second member <NUM> is moveable between a fully retracted position (as is illustrated in <FIG>), at which the distal ends of the guard teeth <NUM> are located at or abut distal regions of the comb teeth <NUM>, and a fully extended position (<FIG>), at which the distal ends of the guard teeth <NUM> are located at or abut the comb teeth <NUM> at regions of the comb teeth <NUM> that are proximal the support body <NUM> of the second member <NUM>. In the fully retracted position, the hair comb <NUM> is set to its shortest hair cutting length, whereas the hair comb <NUM> is set to its longest hair cutting length when in the fully extended position.

The distal ends <NUM> of the comb teeth <NUM> curve upwards at their forward ends (i.e. furthest from the support body <NUM> in the cutting direction x) away from the skin surface to define curved portions having rear facing surfaces <NUM> which face backwards in the cutting direction x. The rear facing surfaces <NUM> and the guard-facing surfaces <NUM> define a discontinuous shoulder configured to extend around the cutting element <NUM> and cutting edge <NUM> of the clipper <NUM> when the comb <NUM> is set to the fully retracted position (i.e. its shortest hair cutting length setting) as shown in <FIG>.

A part of the guard-facing surface <NUM> of one (in this embodiment each) of the comb teeth <NUM> is indented, sunk, or recessed back from a remaining area of the guard-facing surface <NUM> to form a surface depression. The surface depression defines a space which is bounded by comb material, including that of the remaining area of the guard-facing surface <NUM> of the comb tooth. The space is suitable for receiving a corresponding guard tooth <NUM> of the cutting head <NUM> and the hair comb <NUM> is configured to cooperate with the cutting head <NUM> such that, when the hair comb <NUM> is attached to the cutting head <NUM>, at least a distal end of a guard tooth <NUM> is received within the space defined by the surface depression to engage the comb tooth <NUM>.

In the present embodiment, the surface depression is in the form of a groove <NUM> which extends lengthwise in a longitudinal direction of the comb tooth <NUM> between a first end <NUM> proximate the support body <NUM> of the second member <NUM> and a second end <NUM> at the rear facing surface <NUM> proximate the distal end <NUM> of the comb tooth <NUM> from the support body <NUM>. The groove <NUM> extends normal to the cutting edge <NUM> and parallel to the first direction <NUM> along which the second member <NUM> translates relative to the first member <NUM>. In that regard, the guard teeth <NUM> slide within (but not necessarily in contact with, e.g. the internal surfaces of) the grooves <NUM> as the second comb member <NUM> translates relative the first comb member <NUM> to adjust a hair cutting length. In other embodiments, however, the groove may extend lengthwise in a lateral direction of the comb tooth <NUM>, along which the comb teeth <NUM> are spaced apart. Further, the comb tooth <NUM> may have more than one such groove, where those grooves are located on the guard-facing surface <NUM> at distinct longitudinal positions away from the support body <NUM> of the second member <NUM>, each distinct longitudinal positions corresponding to a different hair cutting length of the comb <NUM>.

In the present embodiment, every other one of the guard teeth <NUM> in a lateral direction along which the guard teeth <NUM> are spaced is received in a groove <NUM> of a corresponding one of the comb teeth <NUM>. To facilitate this, the pitch between adjacent comb teeth <NUM> (and grooves <NUM>) in the lateral direction is equal to twice the pitch of adjacent guard teeth <NUM> in the lateral direction. Accordingly, when the comb <NUM> is attached to the cutting head <NUM> of the clipper <NUM>, the grooves <NUM> will have the same lateral positions as (half of) the guard teeth <NUM>, so that the guard teeth <NUM> will be received in those grooves <NUM>.

At least a distal end <NUM> of the guard tooth <NUM>, which is the forwardmost region of the guard tooth <NUM> in the cutting direction x, is received in the groove <NUM>. To facilitate this, and as best illustrated in <FIG>, the hair comb <NUM> is configured to co-operate with the cutting head <NUM> such that, when the hair comb <NUM> is attached to the cutting head <NUM>, the outer surface <NUM> of the outer guard member <NUM> at the distal end <NUM> is inclined at an angle, Θ, with respect to the guard-facing surface <NUM> such that a front surface <NUM> or tip of the guard tooth <NUM> opposite the main body <NUM> points towards the groove <NUM>. It will be appreciated here that the geometry and size of the comb <NUM> may be tailored and designed such that the front surface <NUM> will be oriented to point towards the groove <NUM> when the comb <NUM> is attached to the cutting head <NUM>. For example, with reference to <FIG>, the first member <NUM> of the comb <NUM> is substantially wedge shaped in that its thickness in a direction perpendicular to the cutting edge <NUM> and the first direction <NUM> tapers (reduces) towards the forwardmost end of the first member <NUM> in the cutting direction x. In other embodiments, however, the distal ends <NUM> of the guard teeth <NUM> may be inclined at an angle with respect to the main body <NUM> of the outer guard member <NUM>, which is substantially planar, such that the front surface <NUM> will face the groove <NUM> when the comb <NUM> is attached to the cutting head <NUM>. The distal ends <NUM> of the guard teeth <NUM> may point outwardly from the clipper body.

By receiving the guard teeth <NUM> in spaces formed by the depressions, the guard teeth <NUM> will engage the comb teeth <NUM> in a manner that at least partly restricts movement of the comb teeth <NUM>. In this way, it may be possible to increase the overall robustness and quality of the hair comb <NUM>, and consequently its ability to consistently and uniformly lift and guide hairs to the cutting element.

As best illustrated in <FIG>, which schematically shows cross-sectional views of alternative groove arrangements a) and b), the groove <NUM> comprises two side walls <NUM> which form two lateral sides of the groove <NUM> in the lateral direction parallel to the cutting edge <NUM> of the cutting head.

A guard tooth <NUM> is received in the space defined between the side walls <NUM> to engage the groove <NUM>. The guard tooth <NUM> need not abut the side walls <NUM>, such that some relative movement between the guard tooth <NUM> and the corresponding comb tooth <NUM> may be permitted, e.g. until the guard tooth <NUM> will abut one of the side walls <NUM> of the groove <NUM> and restrict or prevent further lateral movement of the comb tooth <NUM>. In embodiments, however, relative movement between a guard tooth <NUM> and the corresponding comb groove <NUM> may be prohibited. The extent by which a comb tooth <NUM> is permitted to move relative to the guard tooth <NUM> will depend on, amongst other things, a lateral extent of the groove <NUM> relative to a thickness of the guard tooth <NUM>. In that regard, the groove <NUM> may have a lateral extent <NUM> between the two side walls <NUM> that is equal to (<FIG>) a thickness <NUM> of the front surface <NUM> or tip of the guard tooth <NUM>, such that the guard tooth <NUM> may be snugly received in the space between the side walls. The groove <NUM> may instead have a lateral extent <NUM> between the two side walls <NUM> that is greater than (<FIG>) a thickness <NUM> of the front surface <NUM> or tip of the guard tooth <NUM>, to define a gap between the guard tooth and the side walls <NUM> when in the engaged stated. In that case, the comb tooth is allowed to move by a distance corresponding to the size of the gap, i.e. until one of the sides of the depression abuts the guard tooth to restrict or prevent further movement.

The extent of lateral restriction may be increased by providing a groove <NUM> that has a shape that conforms to the shape of the distal end <NUM> of the guard tooth <NUM>. In embodiments such as that shown in <FIG>, a thickness of the guard tooth <NUM> in the lateral direction tapers towards the distal end <NUM> of the guard tooth <NUM>, and the groove <NUM> has a lateral extent <NUM> that tapers towards a bottom of the groove <NUM>. Specifically, the side walls <NUM> may be angled to meet each other at the bottom of the groove <NUM>, to define a V-shaped profile in cross-section, as shown in <FIG>.

In an alternative embodiment, such as that shown in <FIG>, the bottom of the groove <NUM> comprises a base <NUM> which defines, together with the side walls <NUM>, a U-shaped profile in cross-section. In that case, the side walls <NUM> may be substantially vertical, although one or more of the side walls <NUM> may deviate from vertical. It will also be appreciated that although <FIG> shows the side walls <NUM> and base <NUM> being substantially linear (planar), this is not required.

The size of the grooves <NUM> relative that of the distal ends <NUM> of the guard teeth <NUM> may be tailored to set the amount by which the guard teeth <NUM> are received in the grooves <NUM>. In the embodiments illustrated in <FIG>, the groove <NUM> has a depth <NUM> such that at least <NUM>% of the height <NUM> of the front surface <NUM> or tip is received within the space defined by the groove <NUM> and is beneath the remaining guide-facing surface <NUM> (i.e. the part of the guide-facing surface <NUM> that does not form an interior surface of the groove <NUM>).

The outer profile of the guard-facing surface <NUM> and the comb tooth <NUM> together define, when engaged, a hair guiding interface comprising surfaces for directing hairs that are received between adjacent comb teeth <NUM> to the inner cutting member <NUM>. Accordingly, by effectively sinking at least a part of the guide tooth <NUM> below the surrounding guard-facing surface <NUM>, that part does not define the outer profile and is therefore prevented from forming part of a hair guiding interface. This may provide an improved arrangement in which the guard teeth <NUM> present less of an obstacle to hairs in the hair transport path through to the cutting edge <NUM>.

With reference to <FIG>, as the system <NUM> is moved in the cutting direction x, hairs <NUM> are brought towards the comb <NUM> to be cut. The hairs <NUM> may be tangled and orientated randomly from their roots <NUM> on the surface of the skin (not shown). Therefore, as hairs <NUM> having roots <NUM> positioned adjacent a comb tooth <NUM> enter the comb <NUM> and are separated and untangled from hairs having roots positioned on a different side of the comb tooth <NUM>, some of those hairs <NUM> may fall and lie across the guard-facing surface <NUM> at a location that is forwards of the guard teeth <NUM> in the cutting direction x. Those hairs <NUM> will then be lifted and guided towards the cutting edge <NUM> downstream of the comb tooth <NUM>.

In conventional arrangements, the guard teeth <NUM> will lie on an upper or outer-most region of the guard-facing surface <NUM> and pose a barrier or step height that can collide with and prevent hairs that lie across the guard-facing surfaces <NUM> from being raised and guided to the cutting edge <NUM>. This is exacerbated at long hair cutting length settings, similar to the fully extended position of <FIG>, at which the spacing between the cutting edge <NUM> and the rear facing surfaces <NUM> of the comb teeth <NUM> in the first direction <NUM> is increased, thereby exposing a larger area of the guard-facing surface <NUM>. This problem decreases the number of hairs that are cut by the cutting element <NUM> despite having root positions that are between adjacent comb teeth <NUM>. Further, even hairs that do overcome the obstacle posed by the guard teeth <NUM> may not be adequately raised before entering the cutting region. This is because hairs may be pushed away from the cutting region by the guard teeth <NUM> as they overcome the step-height. Such arrangements can therefore lead to an uneven and incorrect hair length end result which may differ for different strokes through the hair.

Accordingly, by receiving at least the distal end of a guard tooth <NUM> in the groove <NUM>, the comb <NUM> will hide that section of the guard tooth <NUM> beneath the upper or outermost region of the guard-facing surface <NUM>, and consequently the hairs <NUM> that fall onto the upper or outermost region of the guard-facing surface <NUM> at a location that is forwards of the guard tooth <NUM> in the cutting direction x. In this way, hairs <NUM> that fall onto the guard-facing surface <NUM> of the comb tooth <NUM> encounter a smaller step height to be overcome (and in some cases no step height at all) when they meet the guard teeth <NUM> during a cutting stroke through the hair. This may provide an improved arrangement in which the guard tooth <NUM> presents less of an obstacle to hairs in the hair transport path through to the cutting edge <NUM>. The hair <NUM> may therefore be consistently and adequately manipulated to the desired orientation for being cut.

It will be appreciated that the above-described advantage can be realised as long as some of the guard tooth is received within the depression to hide a part of the guard tooth from the hair guiding interface. Therefore, less than <NUM>% of the height of the front surface <NUM> may be received in the depression and thus hidden from the hair guiding interface. However, the more the guard tooth is received in the groove, the less of an obstacle the guard tooth will present to hairs travelling along the hair guiding interface.

Further, although the depression has been described above as being in the form of a groove, this is not required. The depression may have any shape or indeed size that is suitable for receiving and bounding a guard tooth.

Further, the comb tooth <NUM> may have a plurality of depressions arranged in side-by-side or end-to-end relationship along the longitudinal direction of the comb tooth <NUM>, where each depression has a distinct longitudinal position away from the support body <NUM> of the second member <NUM>. For example, each depression may have a distinct longitudinal position corresponding to a different hair cutting length of the comb <NUM>. Adjacent depressions may be separated in the longitudinal direction by a ridge of comb material, the top of which may be coplanar with the remaining area of the guard-facing surface <NUM>. The plurality of depressions may form alternating peaks and troughs in the longitudinal direction, where each depression is formed by a respective trough.

In the manner described above, the present invention may provide consistent and improved hair lifting and guidance, as well as increased robustness.

Claim 1:
A hair comb (<NUM>) for attaching to a cutting head (<NUM>) of a hair-cutting device (<NUM>), the cutting head (<NUM>) having an inner cutting member (<NUM>) and an outer guard member (<NUM>) comprising a main body (<NUM>) and a plurality of guard teeth (<NUM>) extending from the main body (<NUM>) in side-by-side relationship, wherein the hair comb (<NUM>) comprises:
a support body (<NUM>) for attachment to the cutting head (<NUM>); and
a plurality of comb teeth (<NUM>) that extend longitudinally from the support body (<NUM>) in side-by-side relationship;
wherein at least one comb tooth (<NUM>) of the plurality of comb teeth (<NUM>) comprises:
a skin-contact surface (<NUM>) and a guard-facing surface (<NUM>) opposite the skin-contact surface (<NUM>),
wherein the guard-facing surface (<NUM>) has a depression (<NUM>) which defines a space for receiving a distal end (<NUM>) of a guard tooth (<NUM>) when the hair comb (<NUM>) is attached to the cutting head (<NUM>),
wherein, when the hair comb (<NUM>) is attached to the cutting head (<NUM>), the guard tooth (<NUM>) and the at least one comb tooth (<NUM>) have an outer profile which defines a hair guiding interface for directing hairs (<NUM>) to the inner cutting member (<NUM>); and
characterised in that
the depression (<NUM>) extends lengthwise in a longitudinal direction of the comb tooth (<NUM>) such that the depression (<NUM>) restricts lateral movement of the comb tooth (<NUM>) with respect to the guard tooth (<NUM>) when the hair comb (<NUM>) is attached to the cutting head (<NUM>) such that the distal end (<NUM>) of the guard tooth (<NUM>) is prevented from forming part of a hair guiding interface.