External cutting member, hair cutting unit, and hair cutting appliance

Abstract

An outer cutting member (10) configured for use in a hair cutting unit in combination with a rotatable inner cutting member, the base (11) comprising at least one hair cutting track (21) provided with a plurality of hair entry openings and an annular base portion (31) between a central portion (17) of the base (11) and an innermost portion of the at least one hair cutting track (21). The annular base portion (31) is provided with a shaped section between a straight inner section (32) and a straight outer section (33) of the annular base portion (31), the shaped section is annular around a central axis (16) of the outer member (10) and the shaped section is shaped according to a predefined contour seen in a cross-section of the outer cutting member (10) comprising the central axis (16).

Description

Technical Field

[0001] This invention relates to an external cutting member configured for use in a hair cutting unit in conjunction with a rotatable internal cutting member having at least one hair cutting edge for subjecting a portion of skin to hair cutting. The external cutting member is generally cup-shaped and includes a base and an annular wall extending from a circumferential region of the base. The base has an outer base surface configured to face the portion of skin to be subjected to hair cutting on its outer side, and an inner base surface configured to face the internal cutting member on its inner side. The base includes at least one hair cutting track and an annular base portion. The hair cutting track is annular around a central axis of the external cutting member and has a plurality of hair entry openings. The annular base portion is located between a central portion of the base and the innermost hair cutting track closest to the central axis among the at least one hair cutting track.

[0002] Furthermore, the present invention relates to a hair cutting unit comprising an outer cutting member as described above and a rotatably arranged inner cutting member having at least one hair cutting edge, wherein the outer cutting member is arranged in the hair cutting unit to cover the inner cutting member.

[0003] Furthermore, the present invention relates to a hair cutting device comprising at least one hair cutting unit as described above and a mechanism configured to drive an internal cutting member of the at least one hair cutting unit. Background Technology

[0004] This invention belongs to the field of hair cutting instruments, particularly electric hair cutting instruments designed to perform shaving actions, etc., in which hair is cut close to the skin. Typically, a hair cutting instrument includes a head in which one or more hair cutting units are located. A particularly common design uses three hair cutting units in an equilateral triangular configuration. Each hair cutting unit includes a combination of an inner cutting member and an outer cutting member, the outer cutting member being configured to cover the inner cutting member. The outer cutting member has a series of hair entry openings for allowing hair to pass through the outer cutting member to reach and encounter the inner cutting member during the hair cutting action. In practical designs, the outer cutting member is typically cup-shaped and has a substantially circular periphery, wherein the hair entry openings can be shaped like elongated slits extending substantially radially relative to the central axis of the outer cutting member in one or more annular regions constituting one or more hair cutting tracks. Such an outer cutting member is particularly suitable for rotary hair cutting instruments, i.e., hair cutting instruments comprising at least one hair cutting unit, wherein the inner cutting member is arranged to rotate during operation.

[0005] Proper use of a hair cutting instrument involves placing the instrument in an active state, i.e., with the internal cutting member of at least one hair cutting unit rotated, and moving the head over a portion of the skin to be subjected to the hair cutting action. The outer cutting member has a hair cutting track surface for contacting a portion of the skin at one or more hair cutting tracks during the hair cutting action. A hair cutting surface is present in the outer cutting member at the location defining the hair entry opening. In a typical design, the inner cutting member comprises a blade with a hair cutting edge. During the hair cutting action, hair entering the hair entry opening is cut between the hair cutting surface and the hair cutting edge, and thus severed close to the skin.

[0006] In the cup-shaped design of the outer cutting member, the outer cutting member includes a base and an annular wall extending from a circumferential region of the base, wherein the base has an outer base surface configured to face the skin portion to be subjected to hair cutting action on its outer side, and an inner base surface configured to face the inner cutting member on its inner side. One or more hair cutting tracks are located at the base. The base also includes an annular base portion located between a central portion of the base and the innermost hair cutting track among the hair cutting tracks, the innermost hair cutting track being the hair cutting track closest to the central axis of the outer cutting member when viewed radially relative to the central axis of the outer cutting member, and in the case of a single hair cutting track, the innermost hair cutting track is only that hair cutting track. The central portion of the base may include a central support portion configured to rotatably support the internal cutting member. For example, if it is practical for the central portion to include a recess centrally located in the base, the recess may be further used to mount a decorative cover element configured to cover a portion of the outer base surface.

[0007] A known method for manufacturing an external cutting member involves providing a metal sheet and subjecting it to various processes, including deformation processes such as cold forming. In the field of hair-cutting instruments, there is a desire for development aimed at reducing the sheet thickness to, for example, a value of 200 μm, because processing a sheet thickness closer to the desired final thickness of the various portions of the sheet requires fewer manufacturing steps and less energy. However, it appears that reducing the sheet thickness of the external cutting member affects its vibration behavior.

[0008] A significant aspect of the vibration behavior of the outer cutting member lies in the fact that when the outer cutting member is used in a hair cutting unit and the inner cutting member rotates, the interaction between the inner cutting member and the hair cutting surfaces of one or more hair cutting tracks of the outer cutting member causes the outer cutting member to vibrate. The vibration frequency of the outer cutting member is related to the frequency of the corresponding hair cutting edge of the inner cutting member through the hair cutting surfaces of one or more hair cutting tracks of the outer cutting member. The design of the hair cutting unit is typically chosen to keep the vibration of the outer cutting member at an acceptable level. However, design considerations become less important when the vibration frequency of the outer cutting member approaches its intrinsic frequency. It appears that as the sheet thickness of the sheet used to manufacture the outer cutting member decreases, there is a practical risk that the vibration frequency of the outer cutting member will approach its intrinsic frequency as the inner cutting member rotates. If this occurs, a noticeable sound is produced during the rotation of the inner cutting member, which is not perceived by the user. Summary of the Invention

[0009] One object of the present invention is to alleviate the aforementioned problem of noticeable sound generation caused by the vibration of the outer cutting member due to the rotation of the inner cutting member, which is particularly relevant when it is necessary to reduce the sheet thickness of the sheet used to manufacture the outer cutting member, as described above.

[0010] In view of the foregoing, the present invention provides an external cutting member configured to be used in conjunction with a rotatable internal cutting member in a hair cutting unit, the rotatable internal cutting member having at least one hair cutting edge for subjecting a portion of skin to hair cutting action, wherein the external cutting member is generally cup-shaped and includes a base and an annular wall extending from a circumferential region of the base, wherein the base has an external base surface configured to face the skin portion to be subject to hair cutting action on its outer side, and the base has an inner base surface configured to face the internal cutting member on its inner side. Furthermore, the base includes at least one hair cutting track and an annular base portion. The hair cutting track is annular around the central axis of the outer cutting member and has multiple hair entry openings. The annular base portion is located between the central portion of the base and the innermost hair cutting track closest to the central axis among the at least one hair cutting track. In a cross-section of the outer cutting member including the central axis, the annular base portion has a forming section located between a straight inner section and a straight outer section of the annular base portion. Between, the forming section is annular around the central axis and shaped according to a predetermined profile, wherein the forming section includes a first curved connecting region at a location connecting with the straight inner section and a second curved connecting region at a location connecting with the straight outer section, and wherein, in an axial direction parallel to the central axis, the predetermined profile of the forming section involves an axial height difference of at least 80 μm between at least one of the outer base surface and the inner base surface over a radial measurement distance of up to 800 μm relative to the central axis in the forming section.

[0011] According to the invention, the aforementioned problems can be mitigated when the design of the outer cutting member, particularly the design of its base, is adjusted. The invention relates to the understanding that, when the outer cutting member vibrates, the annular base portion located between the central portion of the base and the innermost hair cutting track closest to the central axis in at least one hair cutting track can function as a membrane and thus be largely involved in sound generation. By providing the aforementioned defined shaped section to the annular base portion, the conventional concept of having a generally straight appearance of the annular base portion in the cross-section of the outer cutting member is abandoned, resulting in a reduction or increase in the stiffness of the annular base portion. Based on this, the intrinsic frequency of the outer cutting member is reduced or increased, and the appearance of the shaped section can be selected such that the risk of the intrinsic frequency falling within the vibration frequency range of the outer cutting member, which begins from the use of the outer cutting member, wherein the inner cutting member rotates at an appropriate rotational speed in the context of the hair cutting action, is virtually eliminated.

[0012] As for the foregoing, the present invention relates to adjusting the stiffness of the annular base portion to reduce or increase the intrinsic frequency of the outer cutting member, wherein a beneficial effect on the user's sound perception is obtained by selecting an appropriate appearance for the shaped section of the annular base portion. By applying the invention to the context of an outer cutting member made of a sheet having a sheet thickness of, for example, 200 μm, the sound level produced by the vibration of the outer cutting member caused by the rotation of the inner cutting member can be as acceptable as in the context of an outer cutting member made of a sheet having a greater sheet thickness (e.g., 350 μm or even higher). The invention does not require any drastic measures because the design of the outer cutting member is only slightly altered, thus not impairing hair cutting performance, and there is no need to adjust the design of other components of the hair cutting unit, such as the inner cutting member. The adjusted appearance of the annular base portion can be easily achieved by changing one step in the sheet deformation process performed during the manufacture of the outer cutting member. After this step, a slightly different shape of the annular base portion should be considered, but doing so does not require changing the nature of the process.

[0013] As shown above, the predetermined profile of the forming section involves an axial height difference of at least 80 μm between at least one of the outer base surface and the inner base surface over a radial measurement distance of up to 800 μm in the forming section, allowing useful adjustment of the intrinsic frequency based on the adjustment of the conventional overall straight appearance of the annular base portion in the cross-section of the outer cut member. For example, the axial height difference between at least one of the outer base surface and the inner base surface can be between 80 μm and 150 μm over a radial measurement distance of up to 800 μm in the forming section. The axial height difference between the outer base surface and the inner base surface mentioned above should be understood as a distance in the axial direction that exists between two points on the outer base surface and the inner base surface, respectively, in the cross-section of the outer cut member, which are furthest apart from each other in the axial direction.

[0014] The invention also covers situations where, over a radial measurement distance of up to 650 μm in the molding section, the axial height difference between at least one of the outer base surface and the inner base surface is at least 130 μm. In such cases, for example, over a radial measurement distance of up to 650 μm in the molding section, the axial height difference between at least one of the outer base surface and the inner base surface may be between 130 μm and 200 μm.

[0015] In a practical embodiment of the externally cut member, viewed from the aforementioned cross-section of the externally cut member, the contours of the outer base surface and the inner base surface correspond to each other at least at the location of the forming section. The thickness of the base, measured axially between the inner and outer base surfaces, implies that the thickness of the base is substantially constant over the forming section. This is a reasonable outcome of the manufacturing process if the externally cut member is a sheet-based design as previously suggested and the sheet used in the process has undergone bending. In this practical case, the predefined contour of the forming section involves both an axial height difference of at least 80 μm between the outer base surfaces and at least 80 μm between the inner base surfaces over a radial measurement distance of up to 800 μm within the forming section.

[0016] In practice, this can be such that, at least a major portion of the formed section, the base is further recessed in the axial direction toward the inside of the base than it is in the straight outer section. When the outer base surface is defined as being at a higher level than the inner base surface, this means that at least a major portion of the formed section is at a lower level than the straight outer section. This does not change the fact that the invention also covers the situation where, at at least a major portion of the formed section, the base is further recessed in the axial direction toward the outside of the base than it is in the straight outer section.

[0017] According to a first option within the framework of the invention, the predetermined profile of the forming section is formed into a U-shape, wherein the forming section includes an intermediate region located between a first curved connecting region and a second curved connecting region, and wherein each of the first and second curved connecting regions of the forming section includes two opposing curved portions. In this case, it may be practical if, at the location of the intermediate section of the forming section, the base is recessed more in the axial direction toward the inside of the base than at the location of the first curved connecting region of the forming section connecting to the straight inner section and the location of the second curved connecting region of the forming section connecting to the straight outer section; in other words, if the U-shape is upward in one orientation of the outer cutting member, wherein the outer base surface faces upward and the inner base surface faces downward.

[0018] According to the second option within the framework of the invention, the predetermined profile of the forming section is formed as a horizontally extending S. In this case, it may be practical if, at the location of the first curved connection region of the forming section, the base is further recessed in the axial direction towards the inside of the base than at the location of the second curved connection region of the forming section. In this way, the forming section can be well adapted from a higher position on the side of the innermost hair cutting track of the at least one hair cutting track to a lower position on the side of the central portion of the base in the overall inclined design of the annular base portion.

[0019] As is known from the prior art, a practical choice regarding the appearance of the central portion of the base is one in which the central portion includes a centrally located recess within the base. Alternatively, a central hole may be present in the central portion of the base, adapted to receive a pin, rod-like element, etc. Furthermore, as previously suggested, it is highly likely that the outer cut member is manufactured from sheet material, in which case the outer cut member can be defined as comprising a deformed sheet, wherein a sheet thickness of 200 μm is an example of a suitable initial sheet thickness for such a sheet.

[0020] The above and other aspects of the present invention will become apparent from the following detailed description of a practical embodiment of an external cutting member in a hair cutting unit for a hair cutting instrument, and will be set forth with reference to that detailed description. Attached Figure Description

[0021] The invention will now be explained in more detail with reference to the accompanying drawings, wherein the same or similar parts are indicated by the same reference numerals, and wherein:

[0022] Figure 1 A perspective view of a hair cutting device according to the invention is shown schematically, the hair cutting device including a head in which three hair cutting units according to the invention are located;

[0023] Figure 2 A perspective view schematically illustrating an assembly of an outer cutting member, a decorative cover positioned on the outer cutting member, and an inner cutting member according to the invention, the assembly being... Figure 1 A portion of the hair-cutting unit of the hair-cutting device shown, wherein both the outer cutting member and the cap are shown in a partially cut manner.

[0024] Figure 3 schematically shown Figure 2 A top view of the externally cut components of the assembly shown.

[0025] Figure 4 schematically shown Figure 2 The cross-sectional view of the externally cut component of the assembly shown.

[0026] Figure 5 A cross-section of a portion of an external cutting member according to a first embodiment of the present invention is schematically shown, the cross-section including the central axis of the external cutting member.

[0027] Figure 6 A perspective view of the cut portion of the external cutting member according to a first embodiment of the present invention is schematically shown.

[0028] Figure 7 A cross-section of a portion of an external cutting member according to a second embodiment of the present invention is schematically shown, the cross-section including the central axis of the external cutting member, and

[0029] Figure 8 A perspective view of the cut portion of the external cutting member according to a second embodiment of the present invention is shown schematically. Detailed Implementation

[0030] Figure 1 A rotary shaving device is shown as a practical example of a hair-cutting device 1 according to the invention. The hair-cutting device 1 includes a body 2 and a head 3, the body 2 for being held by a user of the hair-cutting device 1, and the head 3 for contacting the skin portion to be subjected to hair-cutting action. The body 2 of the hair-cutting device 1 is also commonly referred to as a handle. It is practical if the head 3 is detachably or hingedly mounted to the body 2 for various reasons, such as the need to service and / or clean the head 3, the need to replace the head 3 with another type of head, etc. The head 3 includes a plurality of hair-cutting units 4 according to the invention; in the example shown, the number is three. When the hair-cutting device 1 is applied to subject a portion of the skin to hair-cutting action, the actual process of cutting the hair protruding from that portion of the skin occurs at the location of the hair-cutting units 4.

[0031] Each hair cutting unit 4 includes a combination of an outer cutting member 10 and an inner cutting member 40, as will now be referred to. Figures 2-4 Described in more detail. The outer cutting member 10 is generally cup-shaped, including a base 11 having a generally circular periphery and an annular wall 12 extending from a circumferential region 13 of the base 11, thereby adapting the outer cutting member 10 to at least partially accommodate the inner cutting member 40 within it. The base 11 has an outer base surface 14 on its outer side configured to face the skin portion to be subjected to hair cutting action, and an inner base surface 15 on its inner side configured to face the inner cutting member 40.

[0032] A ring-shaped hair-cutting track 21 exists in the cup-shaped base 11 of the outer cutting member 10. The hair-cutting track 21 includes a sheet 22 extending along its width in a generally radial direction relative to the central axis 16 of the outer cutting member 10. Holes between the sheets 22 form hair entry openings 23 for the hair-cutting track 21. The sides of the sheets 22 form hair-cutting surfaces 24 adapted to cooperate with the hair-cutting edges 41 of the hair-cutting elements 42 of the inner cutting member 40 to cut hair. The invention also relates to cases where the hair-cutting track 21 does not include the sheets 22 or includes more than just the sheets 22, for example, where the entire hair-cutting track 21 is provided with a pattern of toothed elements and / or (circular) holes instead of the sheets 22, or where a pattern of toothed elements and / or (circular) holes is provided in addition to the sheets 22. Furthermore, the invention relates to cases in which more than one hair-cutting track 21 exists in the base 11.

[0033] When the inner cutting member 40 is activated to rotate and a portion of the skin comes into actual contact with the outer cutting member 10 at the position of the hair cutting track 21, a hair cutting action can be performed. The activation of the inner cutting member 40 can be performed in a known manner by a drive mechanism of the hair cutting instrument 1, which is not shown in the accompanying drawings. When the combination of the outer cutting member 10 and the inner cutting member 40 moves on that portion of the skin while the inner cutting member 40 is driven to rotate, due to the cooperation between the hair cutting surface 24 of the hair cutting track 21 of the outer cutting member 10 and the hair cutting edge 41 of the hair cutting element 42 of the rotating inner cutting member 40, hair protruding from that portion of the skin is captured in the hair entry opening 23 of the hair cutting track 21 of the outer cutting member 10 and cut at that position.

[0034] In addition to the hair cutting track 21, the base 11 also includes a central portion 17, which includes a central support portion designed to rotatably support the internal cutting member 40 in the hair cutting unit 4. The central portion 17 of the base 11 also supports a decorative cover 50, which is configured to cover a portion of the outer base surface 14. In the example shown, the central portion 17 includes a recess located at the center of the base 11, and the cover 50 includes a protrusion received within the recess.

[0035] Furthermore, the base 11 includes an annular base portion 31 located between the hair cutting track 21 and the central portion 17. Viewed in cross-section of the outer cutting member 10 including the central axis 16, the annular base portion 31 includes a straight inner segment 32, a straight outer segment 33, and a shaped segment 34 located between the straight inner segment 32 and the straight outer segment 33. The shaped segment 34 is annular around the central axis 16 and shaped according to a predetermined profile. On one side, the shaped segment 34 is connected to the straight inner segment 32 of the annular base portion 31 via a first curved connecting region 35, and on the other side, the shaped segment 34 is connected to the straight outer segment 33 of the annular base portion 31 via a second curved connecting region 36.

[0036] In the following text, reference will be made to Figure 5 and Figure 6 The details of the first example appearance of the predetermined contour of the forming section 34 are explained, and references will be made to... Figure 7 and Figure 8 Details of a second example appearance of the predetermined contour of the forming section 34 are explained. For simplicity, in Figure 6 and Figure 8 Details of the hair cutting track 21 of the external cutting member 10 are not shown in the figure.

[0037] In the first example, the predetermined profile of the forming section 34 is formed into a U-shape, wherein the forming section 34 includes an intermediate region 37 located between the first and second curved connecting regions 35, 36, and wherein each of the first and second curved connecting regions 35, 36 of the forming section 34 includes two opposing curved portions 35a, 35b, 36a, 36b. During the manufacturing process of the outer cutting member 10, the U-shaped profile of the forming section 34 is obtained by appropriately deforming the sheet used to manufacture the outer cutting member 10 using deformable members with appropriate profiles and support members on the sheet. In the example shown, the U-shaped profile is obtained by indenting the sheet in an axial direction parallel to the central axis 16 toward the inside of the base 11. As a result, the base 11 is further recessed in the axial direction toward the inside of the base 11 at the position of the middle section 37 of the forming section 34 than at the position of the first curved connecting section 35 of the forming section 34 connecting to the straight inner section 32 and the position of the second curved connecting section 36 of the forming section 34 connecting to the straight outer section 33.

[0038] In the second example, the predetermined profile of the forming section 34 is formed into a horizontally stretched S-shape. During the manufacturing process of the outer cutting member 10, the stretched S-shaped profile of the forming section 34 is obtained by appropriately deforming the sheet used to manufacture the outer cutting member 10 using deformable members with appropriate profiles and support members on the sheet. In the example shown, the stretched S-shaped profile is obtained by indenting the sheet in the axial direction toward the inside of the base 11. Therefore, at the location of the first bent connection region 35 of the forming section 34, compared to the location of the second bent connection region 36 of the forming section 34, the base 11 is further recessed in the axial direction toward the inside of the base 11.

[0039] exist Figure 5 and Figure 7 In the figure, the axial height difference of the outer base surface 14 in the predetermined contour of the forming section 34 is represented by h. In the example case of the U-shaped contour of the forming section 34 shown, the overall axial height difference h of the outer base surface 14 is between the first extreme level of the outer base surface 14 at the position of the middle section 37 and the second extreme level of the outer base surface 14 at the position of the second curved connecting section 36 connected to the straight outer section 33. In the example case of the extended S-shaped contour of the forming section 34 shown, the overall axial height difference h of the outer base surface 14 is between the first extreme level of the outer base surface 14 at the position of the first curved connecting region 35 connected to the straight inner section 32 and the second extreme level of the outer base surface 14 at the position of the second curved connecting region 36 connected to the straight outer section 33. In the example shown, the axial height difference h of the inner base surface 15 in the predetermined profile of the forming section 34 is similar to the axial height difference h of the outer base surface 14 in the predetermined profile of the forming section 34, because the thickness of the outer cutting member 10 is substantially the same at each location.

[0040] Because the forming section 34 is present in the annular base portion 31, the stiffness of the annular base portion 31 differs from that of a conventional annular base portion 31 with a generally straight appearance in the cross-section of the outer cutting member 10. The stiffness can be determined by determining the force-displacement characteristics relative to the force applied to the base 11 in the axial direction toward the inside of the base 11. Experiments show that the annular base portion 31, including the forming section 34 with a U-shaped profile, has reduced stiffness compared to a conventional base, while the annular base portion 31, including the forming section 34 with a stretched S-shaped profile, has increased stiffness. In either case, the characteristics of the outer cutting member 10 are improved, provided that a noticeable sound is produced by the vibration of the outer cutting member 10, caused by the rotational movement of the inner cutting member 40 and other operational aspects. The stiffness of a conventional straight annular base portion 31 is more likely to involve cases where the frequency of such induced vibrations of the outer cutting member 10 is close to the eigenfrequency of the outer cutting member 10, in which case a noticeable sound is produced. By altering the appearance of the forming section 34 to change its stiffness, the intrinsic frequency is changed, further distancing the frequency of vibrations caused by the outer cutting member 10 from its intrinsic frequency. This measurement yields good results when the predetermined profile of the forming section involves an axial height difference h of at least 80 μm between at least one of the outer base surface 14 and the inner base surface 15 over a radial measurement distance of up to 800 μm relative to the central axis 16. In this regard, it should be noted that the actual example of the thickness of the outer cutting member at the location of at least one hair cutting track is less than 100 μm, the actual example of the diameter of the central portion 17 of the base 11 is 2.5 mm, the actual example of the inner diameter of the hair cutting track 21 is 14 mm, and the actual example of the outer diameter of the hair cutting track 21 is 21 mm.

[0041] In such Figure 7 and Figure 8 In the case of the stretched S-shaped profile shown, the predetermined profile of the forming section may include an axial height difference h of about 100 μm between at least one of the outer base surface 14 and the inner base surface 15 over a radial measurement distance of up to 800 μm in the forming section 34. Figure 5 and Figure 6 In the case of the U-shaped profile shown, the predetermined profile of the forming section may have a slightly steep region and may include an axial height difference h of about 150 μm between at least one of the outer base surface 14 and the inner base surface 15 over a radial measurement distance of up to 650 μm in the forming section 34.

[0042] Those skilled in the art will understand that the scope of this invention is not limited to the foregoing examples, but that various modifications and variations can be made therein without departing from the scope of the invention as defined by the appended claims. This invention is intended to be construed as including all such modifications and variations falling within the scope of the claims or their equivalents. Although the invention has been detailed and described in the accompanying drawings and specification, such description and illustration are to be considered merely illustrative or exemplary, and not restrictive. The invention is not limited to the disclosed embodiments. The drawings are schematic, in which details not necessary for understanding the invention may be omitted, and are not necessarily drawn to scale.

[0043] By studying the accompanying drawings, description, and appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments in practicing the claimed invention. In the claims, the word "comprising" does not exclude other steps or elements, and the indefinite articles "a" or "an" do not exclude a plurality. No reference numerals in the claims should be construed as limiting the scope of the invention.

[0044] Unless otherwise expressly stated, elements and aspects discussed in connection with a particular embodiment or in relation to a particular embodiment may be suitably combined with elements and aspects of other embodiments. Therefore, the fact that certain measures are referenced in mutually different dependent claims does not imply that combinations of these measures cannot be advantageously used.

[0045] The terms “comprising” and “including” as used herein will be understood by those skilled in the art to encompass the term “consisting of”. Thus, the terms “comprising” or “including” in one embodiment may mean “consisting of”, but in another embodiment may mean “containing / having / equipped with at least the defined kinds and optionally one or more other kinds”.

Claims

1. An external cutting member (10) configured for use in a hair cutting unit (4) in conjunction with a rotatable internal cutting member (40), the rotatable internal cutting member having at least one hair cutting edge (41) for subjecting a portion of skin to a hair cutting action. The external cutting member (10) is generally cup-shaped and includes a base (11) and an annular wall (12) extending from the circumferential region (13) of the base (11). The base (11) has an outer base surface (14) on its outer side, the outer base surface being configured to face the portion of the skin to be subjected to hair cutting, and the base (11) has an inner base surface (15) on its inner side, the inner base surface (15) being configured to face the inner cutting member (40). The base (11) therein includes: At least one hair cutting track (21) and an annular base portion (31), the at least one hair cutting track being annularly arranged around the central axis (16) of the outer cutting member (10) and equipped with a plurality of hair entry openings (23), the annular base portion being located between the central portion (17) of the base (11) and the innermost hair cutting track of the at least one hair cutting track (21) closest to the central axis (16), In the cross-section of the outer cutting member (10) including the central axis (16), the annular base portion (31) is equipped with a forming section (34) located between the straight inner section (32) and the straight outer section (33) of the annular base portion (31). The forming section is annularly shaped around the central axis (16) and formed according to a predetermined contour. The forming section (34) includes a first curved connecting region (35) at a location connecting to the straight inner section (32) and a second curved connecting region (36) at a location connecting to the straight outer section (33), and Wherein, in the axial direction parallel to the central axis (16), the predetermined profile of the forming section (34) involves the axial height difference (h) of at least one of the outer base surface (14) and the inner base surface (15), the axial height difference being at least 80 μm over a radial measurement distance of at most 800 μm in the forming section (34) in the radial direction relative to the central axis.

2. The external cutting member (10) according to claim 1, wherein the predetermined profile of the forming section (34) relates to the axial height difference (h) of at least one of the external base surface (14) and the internal base surface (15), the axial height difference being between 80 μm and 150 μm over the radial measurement distance of up to 800 μm in the forming section (34).

3. The external cutting member (10) according to claim 1, wherein the predetermined profile of the forming section (34) relates to the axial height difference (h) of at least one of the external base surface (14) and the internal base surface (15), the axial height difference being at least 130 μm over a radial measurement distance of at most 650 μm in the forming section (34).

4. The external cutting member (10) according to claim 2, wherein the predetermined profile of the forming section (34) relates to the axial height difference (h) of at least one of the external base surface (14) and the internal base surface (15), the axial height difference being at least 130 μm over a radial measurement distance of at most 650 μm in the forming section (34).

5. The external cutting member (10) according to claim 3, wherein the predetermined profile of the forming section (34) relates to the axial height difference (h) of at least one of the external base surface (14) and the internal base surface (15), the axial height difference being between 130 μm and 200 μm over a radial measurement distance of up to 650 μm in the forming section (34).

6. The external cutting member (10) according to any one of claims 1-5, wherein, Viewed from the cross section of the outer cutting member (10), the outline of the outer base surface (14) and the outline of the inner base surface (15) correspond to each other at least at the position of the forming section (34).

7. The external cutting member (10) according to any one of claims 1-5, wherein, At least a major portion of the formed section (34), the base (11) is further recessed in the axial direction than it is in the straight outer section (33) toward the inside of the base (11).

8. The external cutting member (10) according to any one of claims 1-5, wherein the predetermined contour of the forming section (34) is formed as a U-shape, wherein the forming section (34) includes an intermediate region (37) at a position between the first curved connecting region (35) and the second curved connecting region (36), and wherein each of the first curved connecting region (35) and the second curved connecting region (36) of the forming section (34) includes two opposing curved portions.

9. The external cutting member (10) according to claim 8, wherein, At the location of the intermediate region (37) of the forming section (34), the base (11) is further recessed in the axial direction toward the inside of the base (11) than at the locations of both the first curved connection region (35) and the second curved connection region (36) of the forming section (34).

10. The external cutting member (10) according to any one of claims 1-5 and 9, wherein the predetermined profile of the forming section (34) is formed into a horizontally extending S-shape.

11. The external cutting member (10) according to claim 10, wherein at the location of the first curved connection region (35) of the forming section (34), the base (11) is further recessed in the axial direction toward the inside of the base (11) than at the location of the second curved connection region (36) of the forming section (34).

12. The external cutting member (10) according to any one of claims 1-5, 9 and 11, wherein the central portion (17) of the base (11) includes a central support portion configured to rotatably support the internal cutting member (40).

13. The external cutting member (10) according to any one of claims 1-5, 9 and 11, comprising a deformable sheet having a thickness of less than 100 μm at the location of the at least one hair cutting track (21).

14. A hair cutting unit (4) comprising an outer cutting member (10) according to any one of claims 1-13 and a rotatably arranged inner cutting member (40), the inner cutting member having at least one hair cutting edge (41), wherein the outer cutting member (10) is arranged in the hair cutting unit (4) to cover the inner cutting member (40).

15. A hair cutting device (1) comprising at least one hair cutting unit (4) according to claim 14 and a mechanism configured to drive the internal cutting member (40) of the at least one hair cutting unit (4).

Images