HAIR-CUTTING APPLIANCE COMPRISING A GUARD ELEMENT

Abstract

A hair-cutting appliance comprising at least 19 hair-cutting units (10), each comprising a guard element (20) and a rotatably arranged hair-cutting element (15) having at least one hair-cutting edge (16), is provided. The hair-cutting units of the hair-cutting appliance are relatively small, abase of the guard element having a diameter in a range of 7 mm to 13 mm. In order to have a relatively small guard element (20) which is of robust and uncomplicated design, and which is capable of contributing to excellent hair-cutting results without causing skin irritation, it is proposed to let both an inner surface (35) and an outer surface (36) of an annular shaving track (30) of the guard element (20) have a conical shape relative to a central axis (21) of the guard element (20), in a similar slanting orientation relative to the central axis (21), in at least a hair-cutting portion of the shaving track (30).

Claims

1. A hair-cutting appliance comprising at least 19 hair-cutting units each comprising a guard element and a rotatably arranged hair-cutting element having at least one hair-cutting edge, wherein the guard element is configured as a guard for the hair-cutting element and arranged in the each hair-cutting unit to cover the hair-cutting element, wherein the guard element is generally cup-shaped and comprises a base and an annular wall extending from the base, wherein a diameter of the base is in a range of 7 mm to 13 mm, wherein the base includes a shaving track which: is annular about a central axis of the guard element; comprises a plurality of hair-entry slits; has an inner surface at a side facing the hair-cutting element in the each hair-cutting unit, and an outer surface at an opposite side; and has a hair-cutting portion which is designed to cover the hair-cutting element in the each hair-cutting unit at a position of an annular hair-cutting track followed by the at least one hair-cutting edge of the hair-cutting element during rotation of the hair-cutting element; wherein, in at least the hair-cutting portion of the shaving track and as seen in a longitudinal section of the guard element including the central axis, at either side of the central axis both the inner surface and the outer surface of the shaving track have: a conical shape relative to the central axis with a similar slanting orientation relative to the central axis; and a straight outline, wherein the inner surface of the shaving track is oriented relative to the central axis at an inclination angle (α.sub.i) in a range of 45° to 78°.

2. The hair-cutting appliance according to claim 1, wherein, in at least the hair-cutting portion of the shaving track, the inclination angle (α.sub.i) of the inner surface of the shaving track is in a range of 60′ to 75°.

3. The hair-cutting appliance according to claim 1, wherein, in at least the hair-cutting portion of the shaving track and as seen in said longitudinal section of the guard element, at either side of the central axis the outer surface of the shaving track is oriented relative to the central axis at an inclination angle (α.sub.o) in a range of 90′ to 120°.

4. The hair-cutting appliance according to claim 1, wherein: the plurality of hair-entry slits of the shaving track have a main extension in a radial direction relative to the central axis the shaving track further comprises elongated lamellae extending between the hair-entry slits, at least some of the plurality of hair-entry slits have a width distribution according to which a width of the respective hair-entry slits increases in a radially outward direction along at least a major portion of a length of the respective hair-entry slits, and at least some of the lamellae have a thickness distribution in which a thickness of the respective lamellae increases in the radially outward direction along at least a major portion of a length of the respective lamellae.

5. The hair-cutting appliance according to claim 4, wherein, along at least said major portion of the length of the respective lamellae, in each radial position the thickness of the respective lamellae is proportional to the width of the hair-entry slits.

6. The hair-cutting appliance according to claim 4, wherein a ratio between a local slit width and a local lamella thickness is between 2.2 and 6.

7. The hair-cutting appliance according to claim 4, wherein the respective hair-entry slits are tapered in a radially inward direction.

8. The hair-cutting appliance according to claim 4, wherein the respective lamellae have a substantially constant width along at least said major portion of their length.

9. The hair-cutting appliance according to claim 4, wherein the width of the respective hair-entry slits is at least 250 μm at any radial position.

10. The hair-cutting appliance according to claim 1, wherein, as seen in said longitudinal section of the guard element, the at least one hair-cutting edge of the hair-cutting element has a shape which is complementary to the shape of the inner surface of the shaving track of the guard element at a position of at least the hair-cutting portion of the shaving track.

11. The hair-cutting appliance according to claim 1, wherein: the hair-cutting element comprises a plurality of legs and a support structure for supporting the plurality of legs, each of the plurality of legs extends towards the inner surface of the shaving track of the guard element and includes a hair-cutting edge from the at least one hair-cutting edge, and the plurality of the legs comprises three, four or five legs.

12. The hair-cutting appliance according to claim 1, further comprising a driving mechanism configured to act on the hair-cutting element of at least one hair-cutting unit for realizing rotation of the hair-cutting element during operation of the hair-cutting appliance at a rotation speed resulting in a frequency of the at least one hair-cutting edge of the hair-cutting element passing the respective hair-entry slits of the guard element being in a range of 315-535 passes per second.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention will now be explained in greater detail with reference to the figures, in which equal or similar parts are indicated by the same reference signs, and in which:

[0024] FIG. 1 diagrammatically shows a perspective view of a conventional hair-cutting appliance;

[0025] FIG. 2 illustrates a comparison between a conventional configuration and a pin-bed configuration of hair-cutting units in a hair-cutting appliance according to the invention;

[0026] FIG. 3 diagrammatically shows a perspective view of a guard element according to an embodiment of the invention, which is intended to be used in a hair-cutting unit of the hair-cutting appliance according to the invention;

[0027] FIG. 4 diagrammatically shows a top view of the guard element;

[0028] FIG. 5 is an enlarged detail A of FIG. 4;

[0029] FIG. 6 diagrammatically shows a view of a longitudinal section of the guard element including a central axis of the guard element;

[0030] FIG. 7 diagrammatically shows a perspective view of a hair-cutting element which is designed to be combined with the guard element in a hair-cutting unit of the hair-cutting appliance according to the invention; and

[0031] FIG. 8 illustrates orientations and outlines of an inner surface and an outer surface of a shaving track of the guard element and indicates how a cutting edge of the hair-cutting element is positioned with respect to the inner surface of the shaving track of the guard element in a hair-cutting unit of the hair-cutting appliance according to the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] FIG. 1 relates to a conventional hair-cutting appliance. In the figure, an electric rotary shaver 1 is shown, which comprises a body 2 and a head 3. The head 3 may be removably or hingably mounted to the body 2. The body 2 of the shaving appliance 1 is also commonly referred to as handle. In the shown example, three hair-cutting units 4 are disposed in the head 3. When the shaver 1 is applied for the purpose of subjecting a skin area to a shaving action, the actual process of cutting off hairs protruding from the skin area takes place at the position of the hair-cutting units 4.

[0033] It may be desirable to arrange more than three hair-cutting units 4 in the head 3 for the reason of improving performance when it comes to following facial contour and realizing effective shaving strokes, for example. In particular, it may be desirable to equip the head 3 with a plurality of relatively small hair-cutting units 10 in a pin-bed configuration. In this respect, FIG. 2 illustrates a comparison between a conventional configuration and such a pin-bed configuration of hair-cutting units in a hair-cutting appliance according to the invention. In the shown example of the pin-bed configuration, 37 hair-cutting units 10 are disposed in the head 3, which does not alter the fact that other numbers of hair-cutting units 10 may be chosen. It follows from an interpretation of the figure that more of the total area of the head 3 is effectively covered by the plurality of hair-cutting units 10 in the pin-bed configuration than by the three hair-cutting units 4 in the conventional configuration. It may be practical for an outer diameter of the relatively small hair-cutting units 10 to be about two to two and a half times smaller than an outer diameter of the conventional, relatively large hair-cutting units 4.

[0034] FIGS. 3-6 and 8 relate to a guard element 20 which is suitable to be used in a relatively small hair-cutting unit 10 of a hair-cutting appliance according to the invention of the rotary type, and FIG. 7 relates to a hair-cutting element 15 which is suitable to be combined with the guard element 20 in the hair-cutting unit 10 and which is designed for rotary arrangement. For the sake of clarity, it is noted that the guard element 20 as will now be described is only one of numerous embodiments which are covered by the invention, and that details of the design of this particular guard element 20 which are outside of the basic definition of the guard element provided in the claims are not to be understood so as to be limiting to the invention, wherein it is further noted that details which may be considered independently by a skilled person are not to be understood so as to be inextricably correlated even though they are disclosed with reference to a single example, unless an indication to the contrary is explicitly given. Likewise, the hair-cutting element 15 as will now be described is only one of numerous embodiments which are covered by the invention, and that details of the design of this particular hair-cutting element 15 which are outside of the basic definition of the hair-cutting element provided in the claims are not to be understood so as to be limiting to the invention, wherein it is further noted that details which may be considered independently by a skilled person are not to be understood so as to be inextricably correlated even though they are disclosed with reference to a single example, unless an indication to the contrary is explicitly given.

[0035] The guard element 20 is of a generally cup-shaped design, having a substantially circular periphery and a central axis 21, whereby the guard element 20 is suitable for at least partially accommodating the hair-cutting element 15 in its interior. In the cup-shaped design, the guard element 20 comprises a base 22 and an annular wall 23 extending from the base 22. The guard element 20 is provided with an annular shaving track 30 for contacting the skin of a user during a shaving action, the shaving track 30 having two concentrically arranged peripheral rims 31, 32, namely an outer peripheral rim 31 and an inner peripheral rim 32. The guard element 20 further comprises lamellae 33 extending along the entire width of the shaving track 30 between the peripheral rims 31, 32, in a substantially radial direction relative to the central axis 21 of the guard element 20. Apertures as present between the lamellae 33 constitute hair-entry slits 34 of the shaving track 30. Sides of the lamellae 33 constitute cutting surfaces suitable for cutting off hairs in cooperation with hair-cutting edges 16 of the hair-cutting element 15.

[0036] A hair-cutting action can be performed when the hair-cutting element 15 of the hair-cutting unit 10 is activated to rotate and a skin area is actually contacted by the guard element 20 at the position of the shaving track 30. When the hair-cutting unit 10 is moved over the skin area, it is achieved that hairs protruding from the skin area are caught in the hair-entry slits 34 of the guard element 20 and are cut off in that position as result of a cooperation between the cutting surfaces as present at the sides of the lamellae 33 delimiting the hair-entry slits 34 and the hair-cutting edges 16 of the rotating hair-cutting element 15.

[0037] As mentioned, the guard element 20 is suitable to be used in a relatively small hair-cutting unit 10. In view thereof, a diameter of the base 22 of the guard element 20, which is the same as an outer diameter of the annular wall 23 of the guard element 20 in the shown example in view of the fact that the annular wall 23 has a straight cylindrical shape, is significantly smaller than a diameter of about 20 mm. For example, the diameter of the base 22 of the guard element 20 may be 9 mm. In general, the diameter as mentioned is in a range of 7 mm to 13 mm.

[0038] In the guard element 20 of the present embodiment, the shaving track 30 is of a design in which the hair-entry slits 34 are tapered in a radially inward direction, as can best be seen in FIG. 5. Further, in the guard element 20 of the present embodiment, a thickness of the lamellae 33 delimiting the hair-entry slits 34 increases in a radially outward direction, as can best be seen in FIG. 6. On the basis of the tapered shape of the hair-entry slits 34, it is achieved that a sufficiently large total hair-entry area is present in the guard element 20, despite of the relatively small size of the guard element 20. Further, the hair-entry slits 34 may still have an effective length, i.e. a dimension in the radial direction, of about 2.5 mm, and it is also possible for the hair-entry slits 34 to be wide enough at every position along its length to actually catch hairs during a shaving action. On the basis of the thickness profile of the lamellae 33, wherein the lamellae 33 have a larger thickness at radial positions which are more outward, disadvantageous effects such as skin doming in the relatively wide portions of the hair-entry slits 34 are counteracted.

[0039] As can best be seen in FIG. 6, both an inner surface 35 and an outer surface 36 of the shaving track 30 have a conical shape relative to the central axis 21 of the guard element 20, in a similar slanting orientation relative to the central axis 21, which is an oblique downward orientation in an outward radial direction in FIG. 6. One of the effects of the conical properties of the guard element 20 at the position of the shaving track 30 is that an advantageous distribution of pressure on the guard element 20 is obtained when the guard element 20 is pressed against a skin area during a shaving action.

[0040] In the embodiment as shown in FIG. 7, the hair-cutting element 15 comprises five legs 17 and a support structure 18 of the legs 17, wherein each of the legs 17 includes a hair-cutting edge 16, so that the total number of hair-cutting edges 16 is also five. In the hair-cutting unit 10, each of the legs 17 extends towards the inner surface 35 of the shaving track 30 of the guard element 20, so that during rotation of the hair-cutting element 15, the hair-cutting edges 16 move over the shaving track 30 at the inside thereof. In view thereof, it is practical for the hair-cutting edges 16 to be designed so as to be compliant with the inner surface 35 of the shaving track 30, i.e. to have an orientation which is in accordance with the slanting orientation of the inner surface 35 of the shaving track 30.

[0041] FIG. 8 provides an illustration of a number of the special features of the guard element 20 as mentioned in the foregoing. In a diagrammatical fashion, FIG. 8 provides a view of a longitudinal section of the guard element 20, at one side of the central axis 21 of the guard element 20. The figure provides an illustration of the fact that the thickness of lamellae 33 of the shaving track 30 increases in a direction which is radially outward with respect to the central axis 21. Also, the figure provides an illustration of the fact that the shaving track 30 has a conical appearance, both at the inner surface 35 and the outer surface 36 thereof, and that the inner surface 35 and the outer surface 36 have a straight outline. According to the invention, an angle α.sub.i of the shaving track 30 to the central axis 21 at the side of the inner surface 35 is in a range of 45° to 78°, and may more particularly be in a range of 60° to 75°. Further, it may be so that an angle α.sub.o of the shaving track 30 to the central axis 21 at the side of the outer surface 36 is in a range of 90° to 120°.

[0042] In FIG. 8, an outline of a portion of the hair-cutting element 15 including a hair-cutting edge 16 is indicated by dashed lines. It is hereby illustrated that the hair-cutting edge 16 is designed so as to have a shape which is complementary to the shape of the inner surface 35 of the shaving track 30 of the guard element 20. On the basis of this fact, it is possible for the hair-cutting element 15 to have a self-centering functionality in the guard element 20, wherein the slanting orientation of the inner surface 35 of the shaving track 30 contributes to this effect. As a consequence, there is no need for having a central bearing for the hair-cutting element 15 in the guard element 20, which is advantageous in view of the fact that space inside the guard element 20 is limited due to the relatively small dimensions of the guard element 20, and also the fact that construction complexity is reduced.

[0043] It will be clear to a person skilled in the art that the scope of the invention is not limited to the examples discussed in the foregoing, but that several amendments and modifications thereof are possible without deviating from the scope of the invention as defined in the attached claims. It is intended that the invention be construed as including all such amendments and modifications insofar they come within the scope of the claims or the equivalents thereof. While the invention has been illustrated and described in detail in the figures and the description, such illustration and description are to be considered illustrative or exemplary only, and not restrictive. The invention is not limited to the disclosed embodiments. The drawings are schematic, wherein details which are not required for understanding the invention may have been omitted, and not necessarily to scale.

[0044] Variations to the disclosed embodiments can be understood and effected by a person skilled in the art in practicing the claimed invention, from a study of the figures, the description and the attached claims. In the claims, the word “comprising” does not exclude other steps or elements, and the indefinite article “a” or “an” does not exclude a plurality. Any reference signs in the claims should not be construed as limiting the scope of the invention.

[0045] Elements and aspects discussed for or in relation with a particular embodiment may be suitably combined with elements and aspects of other embodiments, unless explicitly stated otherwise. Thus, the mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0046] The terms “comprise” and “include” as used in this text will be understood by a person skilled in the art as covering the term “consist of”. Hence, the term “comprise” or “include” may in respect of an embodiment mean “consist of”, but may in another embodiment mean “contain/have/be equipped with at least the defined species and optionally one or more other species”.

[0047] Notable aspects of the invention can be summarized as follows. A guard element 20 which is configured to be used in a hair-cutting unit 10 as a guard for a rotatable hair-cutting element 15 of the hair-cutting unit 10 having at least one hair-cutting edge 16 is described. It is intended to use the guard element 20 in a hair-cutting appliance according to the invention having a plurality of relatively small hair-cutting units 10, wherein the number of hair-cutting units 10 is at least 19, for example 37 or even 61. In order to have a relatively small guard element 20 which is of robust and uncomplicated design, and which is capable of contributing to excellent hair-cutting results without causing skin irritation, it is proposed to let both an inner surface 35 and an outer surface 36 of an annular shaving track 30 of the guard element 20 have a conical shape relative to a central axis 21 of the guard element 20, in a similar slanting orientation relative to the central axis 21, in at least a hair-cutting portion of the shaving track 30. Further, it is proposed to let both the inner surface 35 and the outer surface 36 of the shaving track 30 have a straight outline and to let an angle α.sub.i of the shaving track 30 to the central axis 21 at the side of the inner surface 35 be in a range of 45° to 78° as seen in a longitudinal section of the guard element 20 including the central axis 21, at either side of the central axis 21, in at least the hair-cutting portion of the shaving track 30 as mentioned.

[0048] Assuming that the shaving track 30 includes hair-entry slits 34 having a main extension in a radial direction and elongated lamellae 33 extending between the hair-entry slits 34, it may also be advantageous if at least some of the hair-entry slits 34 have a width distribution according to which a width of the respective hair-entry slits 34 increases in a radially outward direction along at least a major portion of a length of the respective hair-entry slits 34, and if further at least some of the lamellae 33 have a thickness distribution in which a thickness of the respective lamellae 33 increases in the radially outward direction along at least a major portion of a length of the respective lamellae 33.