WO2022129226A1

WO2022129226A1 - Electric shaver

Info

Publication number: WO2022129226A1
Application number: PCT/EP2021/085989
Authority: WO
Inventors: Lennart Kisswani
Original assignee: Mektig Technology Group Ab
Priority date: 2020-12-18
Filing date: 2021-12-15
Publication date: 2022-06-23
Also published as: SE544810C2; EP4263157A1; SE2051489A1

Abstract

Electric shaver, comprising a rotating drum (a), associated with an angular direction (A), a radial direction (R) and an axial direction (L), said drum (a) being arranged to rotate in the angular direction (A) about an axially oriented axis of rotation; one or several angularly distributed cutting edges (b2) and/or one or several cutting blades (bl) fastened to said drum (a) and in turn comprising respective cutting edges (b2), said cutting edges (b2) being arranged to extend in said axial direction (L), said cutting edges (b2) or blades (bl) being associated with a cutting direction (D) in turn being perpendicular to said axial direction (L); a distance means (c), arranged to provide a minimum radial distance between said axis of rotation and skin (g) of a user pressing the rotating drum (a) onto said skin (g); and an electric motor (r), arranged to rotationally drive said rotating drum (a). Said one or several cutting edges (b2) are arranged to be unshielded along at least an unshielded angular distance sufficient for each cutting edge (b2) to come into direct contact with the skin (g) of the user as the drum (a) rotates and the rotating drum (a) is pressed towards or onto the skin (g).

Description

Electric shaver

The present invention relates to an electric shaver.

Electric shavers of several different types are known, having knives or cutting blades that operate in various rotational or translational movement patterns in relation to a user's skin so as to cut off hairs.

The present invention relates to an electric shaver comprising a rotating drum carrying one or several cutting blades or edges having their cutting edges parallel to a rotational axis of the rotating drum. The blades or edges are arranged to cut off hairs as the blade or edge in question passes a location closest to the skin along their rotary path.

For instance, such electric shavers are disclosed in US 2019/0240852 A 1, WO 2020/152684 A 1, US 2008/0060202 A 1.

An electric shaver of this general type is also disclosed in SE 1730213 A 1, having a rotating drum 3, in turn carrying razor blades 4 and rotating about an axis 2. In order to protect the user's skin from being cut by the blades 4, a metal grid 1 is provided. As the shaver is moved across the skin, the hairs of the user penetrate through holes in this grid 1 and are then cut off by the rotating blades 4 as the blades pass said location closest to the skin.

Electric shavers of the above discussed types are generally able to perform a reasonably close shave, but typically require elaborate mechanics in order to achieve this. For instance, the metal grid must be very thin, and the blades need to pass the inside of the metal grid with very little play.

These requirements have resulted in relatively advanced electric shavers in terms of used materials and production technology. Of course, this drives complexity and cost. Hence, there is a need for an electric shaver that is able to perform a close shave but that does not rely on as advanced materials and tight tolerances as conventional electric shavers.

The present invention solves this and other problems.

Hence, the invention relates to an electric shaver, comprising a rotating drum, associated with an angular direction, a radial direction and an axial direction, said drum being ar- ranged to rotate in the angular direction about an axially oriented axis of rotation; one or several angularly distributed cutting edges and/or one or several cutting blades fastened to said drum and in turn comprising respective cutting edges, said cutting edges being ar- ranged to extend in said axial direction, said cutting edges or blades being associated with a cutting direction in turn being perpendicular to said axial direction; a distance means, ar- ranged to provide a minimum radial distance between said axis of rotation and skin of a user pressing the rotating drum onto said skin; and an electric motor, arranged to rota- tionally drive said rotating drum, and is characterised in that said one or several cutting edges are arranged to be unshielded along at least an unshielded angular distance suffi- cient for each cutting edge to come into direct contact with the skin of the user as the drum rotates and the rotating drum is pressed towards or onto the skin.

In the following, the invention will be described in detail, with reference to exemplifying embodiments of the invention and to the enclosed drawings, wherein:

Figure 1 is a perspective view of a rotating drum a useful in an electric shaver according to the present invention, including cutting blades b 1 with respective cutting edges b2, fixedly mounted on the drum a in an operating position of the cutting blades b 1.

Figure 2 shows the drum a in a side cross-section, including the cutting blades b 1 with their cutting edges b2, the cutting edges b2 being in a position radially inside a radially outer geometry of a distance means c. Broken arrows indicate a direction of rotary movement of the drum a. Figure 2 also illustrates a cutting angle d; the skin g of a user, including hair f to be cut off; and, using broken circles, the rotary path of the cutting edges b2 and a radial periphery of the distance means c when the drum a rotates.

Figure 3 shows the drum a with mounted cutting blades b 1 in a front view, also showing an axial dimension or direction L of the drum a. Figure 3 also shows ridges i and valleys j at the periphery of said distance means c. An magnified cut-out h illustrates a radial depth x be- tween said ridges i and valleys j.

Figure 4 shows a handle q with a shaving mechanism comprising the drum a and a shielding means m.

Figure 5 illustratesthe handle q with the shielding means m from above with a section taken over the shielding means m. In the section A-A, the drum a is shown with a cutting blade b 1 locking mechanism n and a drive shaft k of the drum a with a engagement cut-out e for driving the drive shaft k. Figure 5 also shows an opening s in the shielding means m.

Figure 6 shows the handle q with the drum a, with the shielding means m removed. Figure 6 illustrates a blade lock n arranged to fasten a cutting blade b 1, an axial lock o, arranged to limit the axial freedom of motion of the drum a in relation to the drive shaft k, and a stop screw p.

It is noted that all Figures illustrates, using common reference notations, an example of an electric shaver according to the present invention.

Hence, the present invention relates to an electric shaver of the type exemplified in the Figures.

The electric shaver comprises a rotating drum a, associated with an angular direction/di- mension A, a radial direction/dimension R and an axial direction/dimension L. The drum a is arranged to rotate in the angular direction A about an axially oriented axis of rotation running through a centre of the drum a, such as through a (radial) mass centre of the drum a.

The rotational direction R of the drum a is such that the cutting edge or edges b2 strike each hair f as a leading edge with respect to the rest of the cutting blade b 1 in question (or a cutting body in case the drum a comprises one or several fixed cutting edges b2). In other words, the tip of each cutting edge b2 arrives, in the angular direction A, at said hair f before any other part forming the corresponding cutting blade b 1 or supporting the cutting edge b2 in question.

The electric shaver further comprises one or several angularly distributed cutting edges b2 and/or one or several cutting blades b 1 fastened to said drum a and in turn comprising respective cutting edges b2. In case there are more than one cutting edge b2, the cutting edges b2 may be equidistantly angularly distributed about the axis of rotation of the drum a. However, it is also envisioned that such several cutting edges b2 may be non-equidistantly arranged in the angular direction A in relation to each other.

It is noticed that the drum a may have fixedly and permanently arranged cutting edges b2 that do not form part of respective cutting blades, but instead form respective integrated parts of a metal main body of the drum a. For instance, the one or several cutting blades b 1, including said cutting edges b2, may form part of one single, connected metal material body, such as a solid metal material body. Then, these cutting edges b2 may be sharpened as needed after extended use, or the whole drum a may be replaced with a new one, having sharpened cutting edges b2.

In the alternative with cutting blades b 1, such cutting blades b 1 may be replaceable, so that a user can simply replace the one or several cutting blades b 1 as needed, after extended use, while possibly keeping the drum a.

Preferably, the drum a comprises at least two cutting edges b2, even if the present invention can also be implemented using only one cutting edge b2. In many embodiments, the drum b 1 comprises at the most four cutting edges b2. It is preferred to use exactly two cutting edges b2.

Each such cutting edge b2 is arranged to extend in said axial direction L. Preferably, each cutting edge b2 is straight, but could also have a non-straight extension, such as forming a wave pattern or being slightly obliquely set so that one longitudinal end of the cutting edge b2 in question strikes slightly before an opposite longitudinal end of the cutting edge b2 as the drum a rotates.

Each of the cutting edges b2, and the blades b 1 (as the case may be), is associated with a respective cutting direction D, the cutting direction D in question being perpendicular to said axial direction L and may be perpendicular to a main longitudinal direction of the cut- ting edge b2 in question. In the case of an obliquely set cutting edge b2, the axial direction L may be not exactly but substantially perpendicular to said main longitudinal direction of the cutting edge b2. In the case of a mounted flat cutting blade b 1, a flat surface of the cutting blade b 1 ending in the cutting edge b2 in question may generally extend in a plane spanned by the cutting direction D in question and the axial direction L.

The electric shaver further comprises a distance means c of the drum a, arranged to pro- vide a minimum radial distance between said axis of rotation of the drum a and the skin g of the user pressing the rotating drum a onto said skin g, at least across a particular angu- lar interval of the drum a. This minimum radial distance may be provided by the distance means c providing a radially extending body or support arranged to limit the freedom of motion of the skin g radially inwards towards the axis of rotation of the drum a at one or several angular locations of the drum a not occupied by a cutting edge b2. Along said an- gular interval, the distance means c may be provided to achieve such a minimum radial distance of constant radius.

Furthermore, the electric shaver comprises an electric motor r, schematically illustrated in Figure 4, arranged to rotationally drive the rotating drum a. The motor r may be any suita- ble electric motor, powered by a battery or electric connector as is conventional as such. The motor r may drive the drum a for rotational movement of the present type using a suitable power drive system, such as using suitable drive shafts, gears, and so forth. Such drive mechanisms has been described in the art before, such as in the initially mentioned patent documents, and will not be elaborated on herein any further.

According to the invention, the one or several cutting edges b2 are arranged to be un- shielded along at least an unshielded angular distance, interval or subsection sufficient for each cutting edge b2 to come into direct contact with the skin g of the user as the drum a rotates and the rotating drum a is pressed towards or onto the skin g.

That a cutting edge b2 is "unshielded" means, herein, that the electric shaver comprises no parts mechanically blocking access to the cutting edge b2 in question from outside the electric shaver. Preferably, the rotary path of each cutting edge b2 is arranged to extend radially further out from the axis of rotation of the drum a than what would be the case in the same angular direction A for a hypothetical flat and infinitely thin surface being placed on the drum, such as with said shielding m, and covering said unshielded angular subsec- tion. In other words, if the electric shaver was to be placed with the drum a onto a flat sur- face with the unshielded angular subsection against the surface, each cutting edge b2 would penetrate into the surface in question as the drum a would rotate one full lap.

The unshielded subsection is stationary in relation to the electric shaver (and in particular in relation to the handle q), so that the drum a rotates in the rotary direction R in relation to the unshielded subsection during operation.

The present inventors have discovered that such a construction, contra-intuitively, does not result in cutting wounds in the skin g of the user, even if the cutting edges b2 come into direct contact with the skin g. To the contrary, such an electric shaver may be de- signed to provide a very close shaving without resulting in bruises, rashes or other uncom- fortable results for the user. Due to the presence of the distance means c keeping the skin g indented between the passing of each cutting edge b2, the cutting edge b2 will slide across the skin, such as across a distance over the skin g of at least 0.5 mm, such as at least 1 mm, such as at least 2 mm, such as at least 3 mm, such as at least 4 mm, such as at least 5 mm, in direct con- tact with the skin g, cutting off hairs f without cutting into the skin g itself. The travel dis- tance will depend on the size of an opening in a shielding m (if used), the radius of the drum a, the rotational speed of the drum a, and so forth.

The user may continuously control the closeness of the shave by applying more or less pressure onto the skin g from the drum a.

In the following, preferred embodiments will be described.

Hence, as illustrated in the Figures, the electric shaver may comprise a mechanical shield- ing means m, arranged to cover the rotating drum a over a shielded angular distance, in- terval or subsection. The drum a may hence rotate inside or within the mechanical shield- ing means m. See, in particular, section A-A in Figure 4.

The mechanical shielding means m may be any useful type of shield, mechanically pre- venting access to the drum a across said shielded distance, interval or subsection. For in- stance, it may be in the form of a sheet metal shield, such as comprising a generally cylin- drical piece of sheet metal, or a shield manufactured from plastic material. It may have a semi-circular cross-section (it may be cylindrical or conical), in the sense that it may follow a generally cylindrical shape of the drum a, or have other shapes. In the Figures, the shielding means m comprises angularly extending, elongated through holes or slits. These holes provide improved draining during wet shaving, but are not compulsory. In case through holes of the shielding means m are used, as illustrated in the Figures, such through holes are sufficiently small to prevent accidental access by the user's skin g to the drum a through the shielding means m (such as the user's fingers during shaving). The shielding means m may be fixedly connected to the handle q of the electric shaver, at least with respect to rotational movements of the shielding means m in relation to the handle q.

In some embodiments, said shielded angular distance, interval or subsection is comple- mentary to the unshielded angular distance, interval or subsection. This is most clearly il- lustrated in the section A-A of Figure 4, where it can be seen that the shielding means m covers the drum a across a particular angular interval (to the top, right and bottom of the drum a in cross-section A-A), whereas the unshielded interval (to the left in cross-section A-A) is not covered by the shielding means m and hence left open for access to the drum a and cutting edges b2 from outside of the shielding means m. In other words, in this case the shielded angular interval together with the unshielded angular interval cover a full 360° in the angular direction A.

It is preferred that the unshielded angular interval is a connected interval, so that there is only one single angularly arranged opening s in the shielding means m defining said un- shielded angular interval.

Hence, the shielding means m may be arranged with an opening s, defining said un- shielded angular distance, interval or subsection. The opening s may extend across at least the full axial direction L of the cutting edges b2, and also across an angular direction A dis- tance corresponding to said unshielded angular distance. The opening s preferably has a substantially constant angular direction A extension, as seen along the axial direction L.

In some embodiments, a connected part of the unshielded angular distance, interval or subsection is at least 60°, such as at least 85°, wide. Moreover, a connected part of the un- shielded angular distance, interval or subsection may be at the most 180°, such as at the most 160°, such as at the most 140°, wide.

Regarding the distance means c, the drum may comprise one respective distance means c part angularly arranged between each pair of cutting edge b2 used. The distance means c, and in particular each of such distance means c parts, may comprise at least one radial peak being arranged radially further away from the axis of rotation of the drum a than each of said cutting edges b2. Hence, when the drum a rotates and the electric shaver is pressed against the skin g with the unshielded angular subsection di- rected to the skin g, the passage of the distance means c, or of each distance means c part, past the skin g, will force the skin g to bulge slightly radially outwards.

In preferred embodiments, the distance means c is arranged to force the skin g to bulge further than each cutting edge b2.

Namely, said at least one radial peak may be arranged radially further out from the axis of rotation of the drum a as compared to each of said cutting edges b2, such as at least 0.1 mm, such as at least 0.2 mm, such as at least 0.3 mm, radially further out from said axis of rotation.

Correspondingly, said at least one radial peak may be arranged at the most 2 mm radially further out, such as at the most 1 mm, or even 0.5 mm, radially further out, from the axis of rotation as compared to each of said cutting edges b2.

The present inventor has found that particularly good results are achieved when said at least one radial peak is arranged about 0.4 mm radially further out from the axis of rota- tion as compared to at least one of said at least one cutting edges b2 that is arranged radi- ally further out from the axis of rotation, preferably as compared to each of said at least one cutting edges b2 (then being arranged at identical radial distances from said axis of rotation).

The radial peak may be provided with an angular subsection of constant radius, this con- stant radius section measuring at least 2 mm, such as at least 4 mm, in the angular direc- tion. Hence, as the drum a rotates when the electric shaver is pressed against the skin g in said manner, the unshielded distance, interval or subsection may be arranged, in relation to the radial arrangement of the distance means c and the cutting edges b2, so that both the distance means c (or each distance means c part) and each of the one or several cutting edges b2 push directly onto the skin g, forcing the skin g to bulge slightly away from the drum a, as the distance means c or the cutting edge b2 pass the skin along their rotary re- spective path of motion. Furthermore, the distance means c may force a slightly larger such bulging of the skin g than the cutting edges b2.

Moreover, as is most clearly illustrated in Figure 3, the distance means c, or each of said distance means c parts, may be provided with a tooth shape arranged to abut the skin g of the user during operation.

Hence, a radial extreme end of the distance means c, or of each distance means c part, may comprise a series of alternating protrusions and indentations, as seen in a cross-sec- tion of the distance means c taken perpendicularly to the angular direction A and inter- secting the axis of rotation of the drum a, forming angularly extending alternating ridges i and valleys j in turn arranged to slide along the skin g of the user as the drum a rotates and the user presses the rotating drum a onto the skin g and with the unshielded subsec- tion facing the skin g.

This will provide a smoother shaving experience, and also prepares the shape of the skin g for the arrival of the cutting edge b2 behind the distance means c by allowing parts of the skin to be "lifted" (between consecutive distance means c, due to the elasticity of the skin being indented by said distance means c) in connection to the arrival of the cutting edge b2 in question between said consecutive distance means c. This principle also allows for the user to vary the pressure applied to find a comfortable shaving experience for the par- ticular skin type of the user in question.

Said ridges i may be at the most 4 mm higher, such as at the most 2 mm higher, such as at the most 1 mm higher, in the radial direction R, as compared to said valleys j. Moreover, the ridges i may be at least 0.1 mm higher, such as at least 0.2 mm higher, such as be- tween 0.2-1 mm higher, in the radial direction R, as compared to said valleys j. The valleys i may be at least 2 mm long, in the axial direction A. The valleys i may be at the most 10 mm long, such as at the most 5 mm long, in the axial direction A. The ridges j may be at least 1 mm long, in the axial direction A. The ridges j may be at the most 10 mm long, such as at the most 5 mm long, in the axial direction A.

The ridges j, and possibly also the valleys i, may be manufactured from a low-friction ma- terial, or be coated with a low-friction material, such as a low-friction plastic or similar, for instance PA (polyamide) with suitable friction-reducing additives, for example one or sev- eral of fatty acids; esters; stearic acid; metal soaps such as calcium stearate; waxes of hy- drocarbons; and amides.

In some embodiments, the one or several distance means c are arranged to provide said minimum distance across a total angular interval along the drum a of at least 30°, such as at least 50°, and/or at the most 150°, such as at the most 120°. In case there are several distance means c parts, they then together cover a total angular interval of between 30° and 150° or said narrower range.

Furthermore, and as is illustrated in the Figures, the distance means c, and correspond- ingly said distance means c parts, may be arranged not to provide said minimum distance across an angular interval covered by any cutting edge b2, and in particular covered by any cutting blade b 1 being fastened to said drum a. Hence, in case replaceable cutting blades b 1 are used, a total angular interval being occupied by such a replaceable cutting blade b 1 may be not covered by said distance means c, so that the cutting blade b 1 is easily accessi- ble for replacement. In the corresponding case with permanently arranged cutting edges b2 as described above, each cutting edge b2 may be arranged with a corresponding flat surface extending in the cutting direction D from the cutting edge b2 in question, and then the distance means c may be arranged not to cover said flat surface. In either case, a flat surface of the replaceable cutting blade b 1 or a flat surface arranged in connection to the permanently arranged cutting edge b2 may provide a sliding surface for the skin g during operation of the electric shaver.

In some embodiments, each one of the at least one cutting edges b2 is arranged at the end of a metal sheet (such as said sliding surface) extending in the cutting direction D freely at least 0.5 mm and/or at the most 4 mm up to the cutting edge b2 in question, preferably without any radial interference with the distance means c. This is most clearly illustrated in Figure 2.

As described above, each of the one or several cutting edges b2 are set at a cutting angle d, which may preferably be identical for all of said cutting edges b2. It is realized that the cutting angle d is measured in relation to main cutting direction of the sharpened edge in question, which would typically be the cutting direction D illustrated in the Figures. The cutting angle d is also measured in relation to the radial direction R, and may hence be an angle between the radial direction R and the cutting direction D.

Said cutting angle d may be at least 30°, such as at least 35°. The cutting angle d may be at the most 60°, such as at the most 50°. Ideally, the cutting angle d is between 40° and 45°.

The electric motor r may be arranged to rotate the drum a during use of the electric shaver so that cutting edges b2 pass the skin g of the user during operation of the electric shaver at least twice every second, such as at least four times every second. Hence, in case there is only one cutting edge b2, the drum a may then be rotated with at least 120 RPM, such as with at least 240 RPM.

Similarly, the electric motor r may be arranged to rotate the drum a so that cutting edges b2 pass the skin g of the user during operation of the electric shaver at the most twenty times every second, ten times every second, such as at the most six times every second. For a one-edge b2 drum a, this then translates into a drum a rotational velocity of at the most 1200 RPM, such as at the most 600 RPM, such as at the most 360 RPM. For a drum with two cutting edges b2, the present inventors have found that the electric shaver according to the present invention delivers a smooth and agreeable shaving experi- ence, in particular when using standard-type replaceable cutting blades b 1 but also in other cases, when the motor r is arranged to rotate the drum a at least 50 RPM and/or at the most 1000 RPM. Particularly good results are achieved using between 120-300 RPM, and in particular 140-180 RPM, for such a two-edge b2 drum a.

In case there are more cutting edges b2, the rotational velocity may be correspondingly decreased.

The electric motor r may be arranged with a varying motor speed, so that the user can se- lect a desired drum a rotational velocity, such as using a number of predetermined set speeds or control across a continuous spectrum of available speeds. This selection may be made using a per se conventional speed setting controller of the electric shaver, accessible via a suitable user interface to set.

As illustrated in the Figures, the electric shaver comprises a handle q connected to the drum a and the shield m, so that the shield m is fixed in relation to the handle q during op- eration of the electric shaver but the drum a rotates.

The drum a rotation axis is preferably set at an angle of between 80° and 100° to a main longitudinal direction of the handle q. In other embodiments, this angle may be between -10° and 10°. Furthermore, the drum a is preferably attached to (engaging with) the han- dle q at one of its distant ends, whereas the opposite free end of the drum a is free.

Above, preferred embodiments have been described. However, it is apparent to the skilled person that many modifications can be made to the disclosed embodiments without de- parting from the basic idea of the invention. For instance, the electric shaver may comprise additional features, not described herein, such as a battery and a battery charging means, or an electric transformer for a lines con- nection. The drum, distance means, cutting blades, cutting edges and shield may differ in details from the example illustrated in the Figures.

Preferably, standard-type replaceable cutting blades b 1 may be used as described above, and the drum a may then comprise fastening means adapted to fasten such standard-type blades b 1. However, it is foreseeable that bespoke cutting blades may also be used, that may then be arranged to engage with customized fastening means on the drum a.

Hence, the invention is not limited to the described embodiments, but can be varied within the scope of the enclosed claims.

Claims

C L A I M S

1. Electric shaver, comprising a rotating drum (a), associated with an angular direction (A), a radial direction (R) and an axial direction (L), said drum (a) being arranged to rotate in the angular direction (A) about an axially oriented axis of rotation; one or several angularly distributed cutting edges (b2) and/or one or several cutting blades (b 1) fastened to said drum (a) and in turn comprising respective cutting edges (b2), said cutting edges (b2) being arranged to extend in said axial direction (L), said cutting edges (b2) or blades (b 1) being associated with a cutting direction (D) in turn being perpendicular to said axial direction (L); a distance means (c), arranged to provide a minimum radial distance between said axis of rotation and skin (g) of a user pressing the rotating drum (a) onto said skin (g); and an electric motor (r), arranged to rotationally drive said rotating drum (a), c h a r a c t e r i s e d i n that said one or several cutting edges (b2) are arranged to be unshielded along at least an un- shielded angular distance sufficient for each cutting edge (b2) to come into direct contact with the skin (g) of the user as the drum (a) rotates and the rotating drum (a) is pressed towards or onto the skin (g).

2. Electric shaver according to claim 1, wherein the electric shaver furthermore comprises a mechanical shielding means (m), arranged to cover the rotating drum (a) over a shielded angular distance.

3. Electric shaver according to claim 2, wherein said shielded angular distance is complementary to the unshielded angular distance.

4. Electric shaver according to any one of the preceding claims, wherein the unshielded angular distance is at least 60°, such as at least 85°.

5. Electric shaver according to any one of the preceding claims, wherein the shielding means (m) is arranged with an opening across at least the full axial direction (L) of the cutting edges (b2) and an angular direction (A) distance corresponding to said unshielded angular distance.

6. Electric shaver according to any one of the preceding claims, wherein the distance means (c) comprises at least one radial peak being arranged radially further away from the axis of rotation than each of said cutting edges (b2).

7. Electric shaver according to claim 6, wherein said at least one radial peak is arranged at least 0.1 mm radially further out from the axis of rotation as compared to each of said cutting edges (b2).

8. Electric shaver according to claim 6 or 7, wherein said at least one radial peak is arranged at the most 2 mm radially from the axis of rotation as compared to each of said cutting edges (b2).

9. Electric shaver according to any one of the preceding claims, wherein a radial extreme end of the distance means (c) comprises a series of alternating protrusions and indentations, as seen in a cross-section of the distance means (c) taken perpendicularly to the angular direction (A) and intersecting the axis of rotation, forming radially extending alternating ridges (i) and valleys (j) arranged to slide along the skin (g) of the user as the drum (a) rotates and the user presses the rotating drum (a) onto the skin (g) .

10. Electric shaver according to claim 9, wherein said ridges (i) are at the most 4 mm higher, in the radial direction, than said valleys (j).

11. Electric shaver according to any one of the preceding claims, wherein the distance means (c) are arranged to provide said minimum distance across a total angular interval along the drum (a) of between 30° and 150°.

12. Electric shaver according to any one of the preceding claims, wherein the distance means (c) is arranged not to provide said minimum distance across an angular interval covered by any cutting blade (b 1) being fastened to said drum (a).

13. Electric shaver according to any one of the preceding claims, wherein said at least one cutting edge (b2) is set at a cutting angle (d), in relation to the radial direc- tion (R), of between 30° and 60°.

14. Electric shaver according to any one of the preceding claims, wherein said at least one cutting edge (b2) is arranged at the end of a metal sheet extending in said cutting direction (D) freely at least 5 mm up to the cutting edge (b2) in question.

15. Electric shaver according to any one of the preceding claims, wherein the electric motor (r) is arranged to rotate said drum (a) so that cutting edges (b2) pass the skin (g) of the user during operation of the electric shaver at least twice every second, such as at least four times every second.

16. Electric shaver according to any one of the preceding claims, wherein the electric motor (r) is arranged to rotate said drum (a) so that cutting edges (b2) pass the skin (g) of the user during operation of the electric shaver at the most twenty times every second, such as at the most ten times every second.