Patent Description:
In some embodiments, a respective shaving appliance may be equipped with two, three or even more shaving units. Further, to provide for a contour following feature, the shaving units may be mounted in a somewhat pivotable or evasive fashion so that overall the shaving unit may be closely aligned with and contact the user's skin.

<CIT> discloses a shaving unit comprising a rotary cutter having a plurality of cutter blades, each having a cutting edge, the rotary cutter being arranged to rotate about an axis in a direction of movement, a cap having an annular shaving track arranged concentrically about the axis for cooperation with the cutter blades, the shaving track being provided with hair-entry apertures or slots that, seen in the direction of movement, have a frontal edge and a rear edge.

The frontal edges of the hair-entry apertures and the cutting edges of the cutter blades each have a V-shaped portion comprising a central base part interconnecting two associated leg parts mutually enclosing an angle, wherein, in the direction of movement, each central base part of the V-shaped portions of the frontal edges is arranged in front of its associated leg parts, so that the V-shaped portions of the frontal edges point in the direction of movement, and wherein, in the direction of movement, each central base part of the V-shaped portions of the cutting edges is arranged behind its associated leg parts, so that the V-shaped portions of the cutting edges point in a direction opposite to the direction of movement.

In other words, the hair-entry apertures and the cutter blades have a somewhat opposite boomerang-shaped form. In this way, hairs that entered the hair-entry apertures may be gradually pushed towards the tips of the opposite V-shaped forms for being cut there between the cutting edges of the hair-entry apertures of the cap and the cutter blade. Hence, hair cutting primarily takes place in the vicinity of the central tips of the V-shaped elements.

<CIT> discloses a shaving unit having an outer blade fixed to a shaver body and an inner blade which is rotatable relative to the outer blade. The outer blade has a plurality of hair-entry slits each having a cutting edge with a main extension in a radial direction relative to an axis of rotation of the inner blade. The inner blade has a plurality of cutting edges each having a main extension in the radial direction. The inner blade and the hair-entry slits in the outer blade are so arranged that a shearing angle enclosed by the cutting edges of the slits and the cutting edges of the inner blade is constant in any position on the cutting edges. The shearing angle is within a range of <NUM>° to <NUM>°. In a first embodiment, the cutting edges of the inner blade are straight and each extend in the radial direction, while the cutting edges of the slits are curved. In a second embodiment, the cutting edges of the slits are straight and each extend in the radial direction, while the cutting edges of the inner blade are curved.

A general design goal for shaving units is to improve shaving performance and to reduce skin injuries, such as skin irritations, redness, skin domes or bulges, etc. Further, the hair removal capacity is a relevant key issue in the design and performance of shaving units.

Hence, it is an object of the present disclosure to provide for improvements in the design of shaving units which address at least some of the above-mentioned issues. More particularly, it is desirable to present a shaving unit that is skin-friendly, robust, and also provides for a sufficient cutting performance. It is also desirable to arrive at an even further improved cutting smoothness.

Further, it is desirable to present a shaving unit having a certain operation width (i.e. effective cutting width of the annular path) that is arranged in such a way that a major portion of the width is also used for the cutting action.

Hence, it is also desirable to present a shaving unit that is arranged in such a way that hair manipulating prior to hair cutting is reduced by providing the capacity to cut hair basically along the entire (radial) extension of the involved cutting edges.

Further, it is desirable to present a shaving unit that is long-lasting and wear-resistant, and that maintains a certain level of sharpness and accuracy over the operational life span.

In accordance with a first aspect of the present disclosure there is presented a shaving unit comprising:.

The above aspect is based on the insight that setting the slot angle α of the hair-entry slots to a certain rather large value has a positive effect on hair cutting since the likelihood of hairs being simply pushed away towards a limited cutting zone is reduced. In certain embodiments, but not to be understood in a limiting sense, providing cutter blades having similar cutting angles may also contribute thereto. In certain embodiments, but not to be understood in a limiting sense, the cutting angle (referred to herein as angle of inclination β) of the cutter blade (i.e. angle between cutting edge of the cutter blade and radial direction) is basically similar to the slot angle α of the guard cap (i.e. angle between cutting edge of the slot at the guard cap and radial direction). This relation is represented by the shearing angle δ that is relatively small.

As used herein, a positive shearing angle δ means that an angle of inclination β of the cutting edge of the cutter blades with respect to the radial direction is greater than the slot angle α. A negative shearing angle δ means that the angle of inclination β is smaller than the slot angle α.

In other words, in accordance with the above aspect, the rotary cutter and the guard cap may be designed in such a way that basically the full length (radial extension) of the cutting edges of the two parts takes an active part in the hair cutting process.

A further benefit is that there is less hair manipulation which contributes to an overall improvement of the user's comfort. This contributes to an overall improvement of the user's comfort. Since a greater portion of the radial extension of the cutting edges is involved in the cutting operation, the overall wear and the gradation of the cutting edges of both the cutter and the guard cap may be reduced. Overall, the operational life span may be increased.

Further, due to the relatively large inclination angle α between the involved edges of the hair-entry slots and the radial direction, skin doming, skin bulging and similar adverse events increasing the likelihood of skin irritations may be reduced or even avoided. It has been observed that the somewhat inclined overall orientation of the hair-entry slots, as opposed to a strict radial orientation, avoid cutting and clamping of skin in the slots which would cause discomfort.

Further, the inclined orientation of the hair-entry slots avoid what may be referred to as parallel doming, caused by a huge number of radial slots arranged close to one another.

A further advantage is that in accordance with at least some embodiments, thinner cutting blades may be used. Hence, shaving smoothness can be improved.

In accordance with an exemplary embodiment of the shaving unit, the slot angle α is in a range from <NUM>° to <NUM>°.

It has been observed that, as a general rule, the greater the inclination angle is the better the skin friendliness will be. It should be noted that of course in practice there may be other factors of influence that may be an argument against making the inclination angle too large. Anyway, it has been observed in some embodiments that even an inclination angle (slot angle) of greater than <NUM>° is, in terms of user comfort, a viable option that is superior to alternative embodiments having significantly smaller inclination angles.

Skin friendliness may be assessed based on the likelihood and severity of skin burning, redness, etc. As used herein, the slot angle α and the angle of inclination β are acute angles, and not their counterpart obtuse angles formed between the respective edges and the radial direction.

In accordance with another exemplary embodiment, the shearing angle δ is in a range from +<NUM>° to -<NUM>°, preferably in a range from +<NUM>° to -<NUM>°.

Keeping the shearing angle δ relatively small results in an improved performance as the hairs are not gradually pushed into a rather limited cutting zone, which would involve a certain amount of hair manipulating, but directly processed/cut, due to the cooperation between the cutter and the guard cap. This applies for both positive and negative (small) shearing angles δ. The inclination of the cutting edges of the cutter blades with respect to the radial direction is similar to the inclination of the frontal edges of the hair-entry slots with respect to the radial direction. The frontal edges of the hair-entry slots may be referred to as cutting edges.

As used herein, a radial direction is defined between a center/main axis of the shaving unit and a point of intersection between a radial ray and the involved edge/geometry. Further, when two elements/two cutting edges are involved, the radial direction is defined between the center of the shaving unit and a point of intersection between the edges at the rotary cutter and the guard cap.

In accordance with another exemplary embodiment, the angle of inclination β of the cutting edges of the cutter blades with respect to the radial direction is greater than <NUM>°. Hence, also the cutting edges of the cutter have a certain inclination with respect to the radial direction, whereas, however, often a relatively small angular offset between the cutting edges of the cutter and the frontal edge of the hair-entry slots is present. The cutting edges of the cutter and the frontal edge of the hair-entry slots are generally not parallel, but may be parallel in certain embodiments. The angle of inclination β is composed of the slot angle α and the shearing angle δ.

In accordance with another exemplary embodiment, the hair-entry slots have a basically straight main extension. This may involve, in certain embodiments, also slightly curved shapes of the hair-entry slots. When a curved shape of the hair-entry slots and also of the respective edges is present, the above angular ranges and values may be determined based on a mean slope and/or a respective tangent line.

In accordance with another exemplary embodiment, the cutter blades have a basically straight main extension. This may involve, in certain embodiments, also slightly curved shapes of the hair-entry slots. When a curved shape of the cutter blades and also of the respective cutting edges is present, the above angular ranges and values may be determined based on a mean slope and/or an imaginary tangent.

In accordance with another exemplary embodiment, the frontal edges of the hair-entry slots are curved in the radial direction relative to the rotation axis. As used herein, the term curved may relate to slightly curved shapes of the hair-entry slots.

In accordance with another exemplary embodiment, wherein the frontal edges of the hair-entry slots are curved in the radial direction relative to the rotation axis, wherein the hair-entry slots and the cutter blades preferably have the same curvature orientation (apex or tip pointing in the same direction).

As used herein, the term curved may relate to slightly curved shapes of the hair-entry slots and/or the cutter blades of the cutter.

In accordance with another exemplary embodiment, the hair-entry slots have a V-shaped main extension. In accordance with another exemplary embodiment, the tips of the V-shaped hair-entry slots are front-oriented, seen in the direction of movement.

In other words, the hair-entry slots may be boomerang-shaped, whereas a tip between the two legs thereof points in the movement/rotation direction. Consequently, the two legs of the V-shape are open towards the rear edge of the hair-entry slots, that is, opposite to the direction of movement.

In accordance with another exemplary embodiment, the cutter blades have a V-shaped main extension. In accordance with another exemplary embodiment, the tips of the V-shaped cutter blades are front-oriented, seen in the direction of movement.

Hence, also the cutter blades may be boomerang-shaped. However, as opposed to the arrangement disclosed in <CIT>, the V-shape defined by the cutter blades is not oriented opposite to the V-shape defined by the hair-entry slots. In other words, a tip between the two legs of the V-shaped cutter blade and the respective cutting edge points forwards, in the movement direction. Put differently, the two legs of the V-shape are open backwards.

It is to be noted in this context that in an embodiment comprising V-shaped forms for the hair-entry slots and/or the cutter blades, a transition (tip area) between the two opposite legs shall not be used to define the slot angle α and/or the shearing angle δ, and the resulting angle of inclination β.

Hence, the cutters and the hair-entry slots are not opposed to one another to urge the hairs into a decreasing cutting zone close to the respective tips of the V-shape. Rather, is more likely that hairs are cut without being manipulated too much.

In accordance with another exemplary embodiment of the shaving unit, at the hair-entry slots and the cutter blades two cutting portions are present, one of which being defined as a first leg of, respectively, the V-shaped hair-entry slots and the V-shaped cutter blades, and the other one being defined as a second leg of, respectively, the V-shaped hair-entry slots and the V-shaped cutter blades.

Hence, not only one but two cutting portions are present, each of which may be defined and shaped in accordance with at least some aspects of the present disclosure.

In accordance with another exemplary embodiment, the first and the second legs have opposite inclination angles with respect to the radial direction.

The respective inclination angles (with respect to the instantaneous radial direction) of the hair-entry slots and the cutter blades may be the same, or may be different on both legs.

In accordance with another exemplary embodiment, an angle ε, which is enclosed by the cutting edges of the first leg and the second leg of the V-shaped cutter blades, is smaller than an angle γ which is enclosed by the frontal edges of the first leg and the second leg of the V-shaped hair-entry slots.

In other words, in accordance with this embodiment, the V-shape characterizing the cutting edge of the cutter blades is more pointed than the V-shape characterizing the hair-entry slots. In other words, the V-shaped cutting edge of the cutter blade is blunter than the V-shaped frontal edge of the hair-entry slot. Generally, the V-shape is aligned with a circumferential direction.

As a result, hairs that entered the hair-entry slot for being cut between the frontal edge thereof and the cutting edge of the cutter blade are not inevitably pushed to the tip.

In accordance with another exemplary embodiment, a shaving head is presented that comprises two or more shaving units in accordance with at least one embodiment as described herein, and further comprises a support member supporting the shaving units.

In certain embodiments, three shaving units that are provided may form a triangle shaving head of the shaving appliance. In other embodiments, two shaving units are provided that are arranged basically adjacent to one another. Respective rotation axes of the shaving units may be parallel, in certain embodiments. However, in alternative embodiments, the rotation axes of the shaving units are slightly inclined with respect to one another to improve the contour-adapting and the contour-following capability of the shaving appliance. Generally, the shaving appliance may be referred to and arranged as a grooming appliance.

In another aspect of the present disclosure, there is presented a shaving appliance comprising a housing, a shaving head in accordance with at least one embodiment as described herein, and a drive unit to cause rotation of the rotary cutters of the shaving units of the shaving head.

Generally, the shaving appliance comprises a housing having a handle portion and a cutting head where the shaving unit is disposed.

The shaving unit comprises at least one shaving unit formed by a cutter blade and a guard blade. The cutter blade may be referred to as rotary cutter. The guard blade may be referred to as guard.

In certain embodiments, the shaving appliance comprises two respective shaving units that are basically parallel or at least slightly inclined to one another. In alternative embodiments, the shaving appliance comprises three respective shaving units that are basically parallel or at least slightly inclined to each other and that are arranged in a triangular fashion at the cutting head of the appliance.

As already indicated further above, the shaving units may be arranged in a somewhat pivotable manner to provide the shaving unit with a certain skin contour following capacity.

Generally, the shaving appliance may be arranged as a rotary shaving appliance having rotary shaving units. This involves a relative rotation between the rotary cutter and the guard cap when the appliance is operated.

The shaving appliance is generally equipped with one or more motors to drive the at least one shaving unit. Further, the shaving appliance may be provided with a battery for power supply. In the alternative, the shaving appliance may be provided with a mains cable for power supply and/or for battery recharging.

<FIG> shows in a perspective top view a hair cutting appliance <NUM> that is arranged as a shaving appliance. The appliance <NUM> comprises an elongated housing <NUM> and a cutting unit <NUM>, <NUM> arranged at a top end of the housing <NUM>.

In the housing <NUM>, a drive unit <NUM> is accommodated (not illustrated herein in much detail). The drive unit <NUM> is arranged to operate and actuate the cutting unit <NUM>, <NUM>. At the housing <NUM>, there may be provided further components of the appliance <NUM>, such as operator controls, a battery, a socket for an electric cable, and such like.

The cutting unit <NUM>, <NUM> comprises a shaving head <NUM> which is releasably provided on a support structure <NUM> of the cutting unit <NUM>, <NUM>. In <FIG>, the shaving head <NUM> is detached and forwarded away from the support structure <NUM> that is attached to the housing <NUM>. The shaving head <NUM> comprises at least two shaving units <NUM> and a support member <NUM> supporting the shaving units <NUM>.

In accordance with the exemplary embodiment of the appliance <NUM> illustrated in <FIG>, the shaving unit <NUM> comprises three shaving units <NUM> that are arranged in a somewhat triangular fashion.

<FIG> is a perspective exploded view of a shaving unit <NUM>. <FIG> illustrates that the shaving units <NUM> each comprise a guard cap <NUM> and a rotary cutter <NUM>.

When the appliance <NUM> is operated for hair shaving procedures, the rotary cutter <NUM> rotates about a rotation axis <NUM> with respect to the guard cap <NUM>.

As illustrated in <FIG>, the shaving units <NUM> may be somewhat inclined with respect to each other. Further, the shaving units <NUM> may be at least slightly pivotable about an axis that is not parallel to the rotation axis <NUM>, preferably perpendicular thereto. This allows for a certain contour following capacity of the shaving head <NUM>.

In <FIG>, respective drivers <NUM> of the driving unit <NUM> are indicated, wherein the drivers <NUM> are arranged to engage respective driving recesses <NUM> provided at the rotary cutters <NUM> of the shaving units <NUM>.

A rotation direction of the rotary cutter <NUM> of each shaving unit <NUM> with respect to the (stationary and non-rotating) guard cap <NUM> is indicated by a curved arrow designated by numeral <NUM> in <FIG>.

In the guard cap <NUM> as shown in <FIG>, an annular shaving track <NUM> is formed. In the mounted state, cutter blades that are formed at the rotary cutter <NUM> contact the interior of the guard cap <NUM> in the region of the annular shaving track <NUM>. A relative rotation between the guard cap <NUM> and the rotary cutter <NUM> allows hairs to be cut between the involved cutting edges of the two main components of the shaving unit <NUM>.

Further reference is made to the perspective exploded top view of <FIG>, providing an enlarged illustration of a guard cap <NUM> and a rotary cutter <NUM> that form a shaving unit <NUM> in accordance with at least some aspects of the present disclosure.

Additional reference is made to <FIG>, showing top views of the guard cap <NUM> and the rotary cutter <NUM>, and to <FIG>, illustrating and assembly state of the guard cap <NUM> and the rotary cutter <NUM>.

Additional reference is made to <FIG>, illustrating an enlarged partial top view of the shaving unit <NUM> to explain the geometry and shape of the hair-entry slots <NUM> and the cutter blades <NUM>.

In <FIG>, the rotation axis <NUM> and the rotation direction <NUM> are indicated by respective numerals. At the guard cap <NUM>, an annular shaving track <NUM> is formed at the rear side thereof (covered by the front face of the guard cap <NUM> in <FIG>). At the annular shaving track <NUM>, a series of hair-entry slots <NUM> is formed and circumferentially distributed about the rotation axis <NUM>.

The hair-entry slots <NUM> each comprise a frontal edge <NUM> and a rear edge <NUM>, as seen in the direction of movement of the rotary cutter <NUM> with respect to the guard cap <NUM>. The frontal edge <NUM> of the hair-entry slots <NUM> may also be referred to as cutting edge of the guard cap <NUM>.

The hair-entry slots <NUM> are arranged and spaced apart from one another about a center of the guard cap <NUM> by constant or non-constant spacing angles (angular offset).

The rotary cutter <NUM> illustrated in <FIG> comprises a base plate <NUM> and a plurality of cutter blades <NUM> extending and/or protruding therefrom. The cutter blades <NUM> are arranged circularly. The cutter blades <NUM> form a wreath or crown-like arrangement.

At a respective top end of the cutter blades <NUM> facing the annular shaving track <NUM>, respective cutting edges <NUM> are formed that cooperate with the frontal edges <NUM> of the hair-entry slots <NUM> at the guard cap <NUM>.

The rotary cutter <NUM> further comprises a driving contour <NUM> formed at the base plate <NUM>. Via the driving contour <NUM>, the rotary cutter <NUM> may be activated and rotated by a driving unit (see the arrow <NUM> indicating the rotation direction) with respect to the guard cap <NUM>.

As can be seen in <FIG>, the hair-entry slots <NUM> of the embodiment illustrated in <FIG> are basically V-shaped or boomerang-shaped.

<FIG> shows that the V-shaped hair-entry slots <NUM> include also respectively shaped frontal edges <NUM>. The frontal edges <NUM> comprise a tip <NUM> which may also be referred to as frontal tip, and a first leg <NUM> and a second leg <NUM>. The tip <NUM> points in a direction of rotation of the rotary cutter <NUM>. In the exemplary embodiment illustrated in <FIG>, also the rear edges <NUM> of the hair-entry slots <NUM> are V-shaped.

Overall, the V-shaped hair-entry slots <NUM> are, in terms of their lengthwise extension, arranged to be basically perpendicular to a circumferential direction, and basically aligned with a radial direction. The same applies to the frontal edges <NUM>.

As can be best seen in <FIG>, also at the cutter blades <NUM> of the rotary cutter <NUM>, a V-shaped or boomerang-shaped form is provided. The cutting edge <NUM> comprises a tip <NUM> and two adjacent legs <NUM>, <NUM>. The tip <NUM> is arranged between a first leg <NUM> and a second leg <NUM>. Overall, the V-shaped cutting edges <NUM> are, in terms of their lengthwise extension, arranged to be perpendicular to a circumferential direction, and basically aligned with a radial direction.

In <FIG>, an angle between the two legs <NUM>, <NUM> of the frontal edge <NUM> is indicated by γ (gamma). Further, as can be seen in <FIG>, an angle between the two legs <NUM>, <NUM> of the cutting edge <NUM> is indicated by ε (epsilon).

In accordance with at least some embodiments of the present disclosure, the angle γ between the two legs <NUM>, <NUM> of the frontal edge <NUM> is greater than the angle ε between the two legs <NUM>, <NUM> of the cutting edge <NUM>. Further, both the frontal edge <NUM> and the cutting edge <NUM> point in the same direction (and also in the same direction as the rotation direction <NUM>).

The design of the hair-entry slots <NUM> and the cutter blades <NUM> has the effect that hairs are not (primarily) pushed towards the tips of the frontal edges <NUM>, but basically processed/cut along the entire (radial) extension of the frontal edges <NUM>. Hence, the risk of having a large number of hair filaments trapped at the tip <NUM> is significantly reduced.

<FIG> shows an assembled state of the rotary cutter <NUM> and the guard cap <NUM>, where the cutter blades <NUM> are arranged in the annular shaving track <NUM> to cooperate with the hair-entry slots <NUM>. In <FIG>, the rotary cutter <NUM> is illustrated by dashed lines and covered by the guard cap <NUM>.

<FIG> illustrates further aspects of the design of the rotary cutter <NUM> and the guard cap <NUM> in accordance with at least some embodiments of the present disclosure. In <FIG>, a partial top view of the guard cap <NUM> and the rotary cutter <NUM> is provided, wherein the rotary cutter <NUM> is represented by a simplified illustration of a top face of a cutter blade <NUM> facing the annular shaving track <NUM> (refer to <FIG>), wherein hidden lines of the cutter blade <NUM> are illustrated by dashed lines.

In <FIG>, a radial direction departing from the (central) rotation axis <NUM> is indicated by <NUM>. For definition purposes, the ray <NUM> defining the radial direction intersects with a (temporary) point of intersection between the frontal edge <NUM> and the cutting edge <NUM>.

Reference numeral <NUM> indicates a cutting portion along a long side extension of the frontal edges <NUM> of the hair-entry slots <NUM>. The cutting portion <NUM> is an area where the hair-entry slot <NUM> and the cutter blade <NUM> contact one another and cooperate to cut hair therebetween.

The frontal edge <NUM>, at at least one leg or portion thereof, is arranged at an angle α (alpha) with respect to the radial direction <NUM>. The cutting edge <NUM>, at at least one leg or portion thereof, is arranged at an angle β (beta) with respect to the radial direction <NUM>. The angle α may also be referred to as slot angle. The angle β may also be referred to as inclination angle of the cutting edge <NUM>.

It is apparent from <FIG> that the angle β is greater than the angle α. An angle difference between the angles α and β is indicated by an angle δ (delta) which may also be referred to as shearing angle. As indicated further above, the slot angle α is in a range of between <NUM>° and <NUM>° (degrees). Preferably the slot angle α is in a range of between <NUM>° and <NUM>°.

Preferably, the inclination angle β is selected in such a way that the shearing angle δ is less than +/-<NUM>°. In some embodiments, the shearing angle δ is less than +/-<NUM>°. In some embodiments, the shearing angle δ is less than +/-<NUM>°.

In certain embodiments, the angle γ between the two legs <NUM>, <NUM> of the frontal edge <NUM> is smaller than <NUM>°. In alternative embodiments, the angle γ between the two legs <NUM>, <NUM> of the frontal edge <NUM> is smaller than <NUM>°. In alternative embodiments, the angle γ between the two legs <NUM>, <NUM> of the frontal edge <NUM> is smaller than <NUM>°.

In certain embodiments, the angle ε between the two legs <NUM>, <NUM> of the cutting edge <NUM> is a maximum of <NUM>° but more than <NUM>° smaller than the angle γ. In certain embodiments, the angle ε between the two legs <NUM>, <NUM> of the cutting edge <NUM> is a maximum of <NUM>° but more than <NUM>° smaller than the angle γ.

With reference to <FIG>, an alternative embodiment in accordance with the present disclosure is explained. <FIG> is top half view representation of a guard cap <NUM>. <FIG> is a corresponding top half view representation of a rotary cutter <NUM>.

The guard cap <NUM> is provided with an annular shaving track <NUM> comprising a series of circumferentially arranged hair-entry slots <NUM>. The hair-entry slots <NUM> comprises a frontal edge <NUM> and an opposite rear edge <NUM>. In a direction of movement of the rotary cutter <NUM> (refer to the curved arrow <NUM> in <FIG>), the frontal edge <NUM> is in front of (downstream of) the rear edge <NUM>.

The hair-entry slots <NUM> include a basically linear shape, as opposed to the V-shaped or boomerang-shaped hair-entry slots <NUM> of the embodiment as described in <FIG> two <NUM>. However, a main extension direction of the hair-entry slots <NUM> and/or the main extension of the frontal edge <NUM> is/are somewhat inclined with respect to a respective radial direction (which will be discussed further below in connection with <FIG>).

At the rotary cutter <NUM> that is shown in <FIG>, a circular series of cutter blades <NUM> that are provided with cutting edges <NUM> is formed. Also the cutter blades <NUM> and/or their cutting edges <NUM> are basically linearly shaped but at least slightly inclined with respect to a respective radial direction.

It goes without saying that in addition to the V-shaped and/or curved embodiments and the basically linear embodiments of the hair-entry slots <NUM>, <NUM> and the cutting edges <NUM>, <NUM> discussed herein, also hybrid embodiments are conceivable, i.e. slightly curved hair-entry slots and cutting edges. However, it is preferred that an apex (tip) of such a geometry points in the direction of the rotation. Hence, the frontal edge of the hair-entry slots may be concavely shaped, and the cutting edge of the rotary cutter may be convexly shaped.

<FIG> illustrates an enlarged partial top view of a shaving unit <NUM> comprising the guard cap <NUM> of <FIG> and the rotary cutter <NUM> of <FIG>. It can be clearly seen that the frontal edge <NUM> at the hair-entry slots <NUM> are inclined with respect to the radial direction (refer to the radial ray <NUM> departing from the axis <NUM> at the center of the shaving unit <NUM>).

The frontal edge <NUM> is arranged at an angle α (alpha) with respect to the radial direction <NUM>. The cutting edge <NUM> of the cutter blade <NUM> is arranged at an angle β (beta) with respect to the radial direction <NUM>. The angle α may also be referred to as slot angle. The angle β may also be referred to as inclination angle of the cutting edge <NUM>.

It is apparent from <FIG> that the angle β is greater than the angle α. An angle difference between the angles α and β is indicated by an angle δ (delta) which may also be referred to as shearing angle.

Ranges and values for the slot angle α, the inclination angle β, and the shearing angle δ already have been discussed further above in connection with <FIG>. Those ranges and values may also be applied to the embodiment illustrated in <FIG>.

Overall, the cutting edge <NUM> is more inclined (steeper) with respect to the radial direction <NUM> than the frontal edge <NUM>.

Also the arrangement illustrated in <FIG> in more detail has the effect that it is more likely that hairs are cut at the current position. By contrast, it is less likely if not impossible that hairs are pushed towards the tips of the hair-entry slots <NUM> prior to the cutting action.

Both in <FIG> and in <FIG>, a positive shearing angle δ is shown, which results in the angle of inclination β being greater than the slot angle α. However, in certain exemplary embodiments, a negative shearing angle δ may be present in both configurations, which results in the angle of inclination β being smaller than the slot angle α. Further, in certain exemplary embodiments, the shearing angle can be basically zero, which results in the angle of inclination β and the slot angle α having the same value.

Claim 1:
A shaving unit (<NUM>) comprising:
- a rotary cutter (<NUM>, <NUM>) comprising a plurality of cutter blades (<NUM>, <NUM>) that are provided with a cutting edge (<NUM>, <NUM>), the rotary cutter (<NUM>, <NUM>) being arranged to rotate about a rotation axis (<NUM>, <NUM>) in a direction of movement (<NUM>, <NUM>); and
- a guard cap (<NUM>, <NUM>) comprising an annular shaving track (<NUM>, <NUM>) surrounding the rotation axis (<NUM>, <NUM>) for cooperation with the cutter blades (<NUM>, <NUM>), the shaving track (<NUM>, <NUM>) being provided with hair-entry slots (<NUM>, <NUM>) that, seen in the direction of movement (<NUM>, <NUM>), have a frontal edge (<NUM>, <NUM>) and a rear edge (<NUM>, <NUM>);
wherein the frontal edges (<NUM>, <NUM>) of the hair-entry slots (<NUM>, <NUM>) are, in a cutting portion (<NUM>, <NUM>) along a long side extension of the hair-entry slots (<NUM>, <NUM>), inclined with respect to a radial direction (<NUM>, <NUM>) relative to the rotation axis (<NUM>, <NUM>), wherein a slot angle (α) is defined as an angle of inclination of the frontal edges (<NUM>, <NUM>) of the hair-entry slots (<NUM>, <NUM>) with respect to the radial direction (<NUM>, <NUM>);
wherein a shearing angle (δ), defined as a difference between the slot angle (α) and an angle of inclination (β) of the cutting edges (<NUM>, <NUM>) of the cutter blades (<NUM>, <NUM>) with respect to the radial direction (<NUM>, <NUM>), is in a range from +<NUM>° to -<NUM>°; and
wherein the shearing angle (δ) is defined at an actual point where the frontal edges (<NUM>, <NUM>) and the cutting edges (<NUM>, <NUM>) cooperate
characterized in that the slot angle (α) is in a range from <NUM>° to <NUM>°.