Shaving apparatus with detachable cutting unit

Abstract

A shaving apparatus has at least one cutting unit detachably coupled to a drive mechanism via a coupling having first and second coupling members. The second coupling member has a coupling cavity. A coupling head of the first coupling member is in a form-locking engagement in the coupling cavity to transfer a driving force, and is detachable from the coupling cavity by movement in an axial direction parallel to an axis of rotation of the cutting unit. The second coupling member has a plurality of recesses, each recess extending in a radial direction from the coupling cavity and being delimited by two radially extending side wall sections. Each of the two radially extending side wall sections forms an edge with a bottom surface of the second coupling member, and the edges of each recess converge in a radially outward direction in relation to the axis of rotation.

Claims

1. An internal cutting member for a shaving apparatus, the internal cutting member comprising a coupling member having a coupling cavity adapted to detachably receive a coupling head of the shaving apparatus inside said coupling cavity, wherein said coupling cavity has a plurality of driven surfaces, arranged to receive a driving force to induce a driving torque about an axis of rotation, wherein said coupling cavity has a cavity opening for receiving said coupling head by a movement of said coupling head in relation to said coupling cavity in an axial direction parallel to the axis of rotation, wherein said coupling member has recesses, each recess of said recesses extending in a radial direction relative to the axis of rotation from said coupling cavity and being delimited by two side wall sections which each extends with a radial direction component with respect to the axis of rotation, wherein each of said two side wall sections of the each recess of said recesses forms an edge with a bottom surface of said coupling member, and wherein said edges of the each recess converge on each other in a radially outward direction in relation to said axis of rotation.

2. The internal cutting member according to claim 1, wherein a region of one of said two side wall sections of the each recess constitutes one of said plurality of driven surfaces.

3. The internal cutting member according to claim 1, wherein each of said recesses forms a through-hole in said coupling member.

4. The internal cutting member according to claim 1, wherein at least one of the edges of the each recess is chamfered to form at least one chamfered edge.

5. The internal cutting member according to claim 1, wherein for the each recess only a first edge of the edges formed by the bottom surface and a first side wall section of the two side wall sections opposed to one of the plurality of driven surfaces is chamfered.

6. The internal cutting member according to claim 4, wherein a chamfering of said at least one chamfered edge increases in a radially inward direction toward the axis of rotation.

7. The internal cutting member according to claim 4, wherein said at least one chamfered edge extends at least partially into an adjacent recess, such that at least a part of an edge of the adjacent recess forming a driven surface of the plurality of driven surfaces of the of the adjacent recess is chamfered.

8. The internal cutting member according to claim 1, wherein said bottom surface is sloped in a radially inward direction toward the axis of rotation for guiding the coupling head radially inward with respect to the axis of rotation when applying an axial mounting force.

9. A cutting unit for a shaving apparatus, comprising an external cutting member and the internal cutting member according to claim 1, wherein the internal cutting member is configured to be driven into rotation with respect to the external cutting member about the axis of rotation.

10. A shaving apparatus provided with at least one cutting unit having external cutting member and an internal cutting member, the shaving apparatus comprising: a drive mechanism for driving the internal cutting member into rotation; and a coupling for transferring a driving force from the drive mechanism to the internal cutting member, said coupling comprising a first coupling member having a coupling head and a second coupling member having a coupling cavity for receiving said coupling head to transfer said driving force inducing a driving torque about an axis of rotation of the internal cutting member, wherein said coupling head is detachably inserted into said coupling cavity and is detachable from said coupling cavity by a movement of said coupling head in relation to said coupling cavity in an axial direction parallel to the axis of rotation, wherein said coupling cavity has a plurality of driven surfaces, arranged to receive the driving force to induce the driving torque about the axis of rotation, wherein said coupling member has recesses, each recess of said recesses extending in a radial direction relative to the axis of rotation from said coupling cavity and being delimited by two side wall sections which each extends with a radial direction component with respect to the axis of rotation, wherein each of said two side wall sections of the each recess of said recesses forms an edge with a bottom surface of said coupling member, and wherein said edges of the each recess converge on each other in a radially outward direction in relation to said axis of rotation.

11. The shaving apparatus according to claim 10, wherein said coupling head comprises a plurality of drive surfaces for transmitting said driving force to said plurality of driven surfaces.

12. The shaving apparatus according to claim 11, wherein either said plurality of drive surfaces or said plurality of driven surfaces are curved to allow pivotal movement of the coupling head in said coupling cavity such that an axis of rotation associated with the first coupling member is in an angular displacement relative to the axis of rotation of the internal cutting member.

13. The shaving apparatus according to claim 10, wherein an upper face of said coupling head has a domed geometry.

14. An internal cutting member for a shaving apparatus, the internal cutting member having an axis of rotation and comprising: a carrier; cutter elements located at a circumference of the carrier; and a coupling member having a coupling cavity configured to detachably receive a coupling head of the shaving apparatus inside the coupling cavity, wherein the coupling member has recesses, each recess of the recesses being delimited by two side wall sections and extending in a radial direction relative to the axis of rotation, and wherein the two side wall sections that delimit the each recess are non-parallel to each other.

15. The internal cutting member of claim 14, wherein the two side wall sections of the each recess converge on each other in a radially outward direction in relation to the axis of rotation.

16. The internal cutting member of claim 14, wherein the coupling cavity has a plurality of driven surfaces configured to receive a driving force to induce a driving torque about the axis of rotation.

17. The internal cutting member of claim 14, wherein the coupling cavity has a cavity opening for receiving the coupling head by a movement of the coupling head in relation to the coupling cavity in an axial direction parallel to the axis of rotation.

18. The internal cutting member of claim 14, wherein the each recess has edges formed between a bottom surface of the coupling member and the two side wall sections, and wherein at least one of the edges of the each recess is chamfered to form at least one chamfered edge.

19. The internal cutting member of claim 18, wherein a chamfering of the at least one chamfered edge increases in a radially inward direction toward the axis of rotation.

20. The internal cutting member of claim 18, wherein the at least one chamfered edge extends at least partially into an adjacent recess.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following drawings:

(2) FIG. 1 shows a shaving apparatus according to the invention having three cutting units,

(3) FIG. 2 is a cross-sectional view of a cutting unit of the shaving apparatus shown in FIG. 1,

(4) FIG. 3 is a cross-sectional view of a first coupling member of the shaving apparatus shown in FIG. 1, taken on the line III-III in FIG. 6,

(5) FIG. 4 is a side elevation of the first coupling member shown in FIG. 3,

(6) FIG. 5 is a cross-sectional view of the first coupling member, taken on the line V-V in FIG. 4,

(7) FIG. 6 is a plan view of the first coupling member shown in FIGS. 3 and 4,

(8) FIG. 7 shows the cutting unit of FIG. 2 in a tilted position, and

(9) FIG. 8 is a plan bottom view of a second coupling member of the cutting unit shown in FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(10) FIG. 1 shows a rotary shaving apparatus according to the invention, comprising a housing 1 and a shaving-head holder 2 which is detachable from the housing 1 and/or hinged to the housing 1. Three rotary cutting units 3, also denoted as shaving heads, are arranged in the shaving-head holder 2, each having an external cutting member 4 with hair trap openings 5 and an internal cutting member 6 with cutter elements 7, which can be driven into rotation with respect to the external cutting member 4. The internal cutting member 6 is driven by a motor 8 accommodated in the housing 1.

(11) FIG. 2 shows one of the cutting units 3 on an enlarged scale. The external cutting member 4, which has the shape of a circular cap, is provided with an internal circular groove 9, also denoted as shaving track. A large number of lamellae 10, which are substantially radially directed with respect to the center of the cap, are present in the bottom wall and in the vertical side walls of the groove 9. The hair trap openings 5 extend between these lamellae 10. The external cutting member 4 is provided with a central bearing shaft, which extends in an axial direction parallel to a center line 11 of the external cutting member 4. The bearing shaft is formed by a central projection 12 of the external cutting member 4. The internal cutting member 6 comprises a metal plate-shaped carrier 13, with the cutter elements 7 integrally provided at the circumference of the carrier 13. The end portions of the cutter elements 7 have cutting edges, which cooperate with mating edges of the lamellae 10 for cutting off hairs which project through the hair trap openings 5 into the shaving track. The carrier 13 is fastened to an annular support 14 having a central opening 15. A second coupling member 16 is fastened in the central opening 15 of the annular support 14. The second coupling member 16 is provided with a bearing bush 17 in which the central projection 12 (bearing shaft) of the external cutting member 4 is journaled.

(12) The internal cutting member 6 is driven by a first coupling member 18, which comprises a coupling head 19 and a coupling body 20. For this purpose, the second coupling member 16 has a coupling cavity 21 in which the coupling head 19 can be accommodated. The coupling body 20 is fastened to a drive shaft 22 of the motor 8, with resilience in the axial direction. For this purpose, a spring 23 is mounted between the coupling body 20 and the drive shaft 22. It is noted that, between the motor 8 and the coupling body 20, gear wheels may be arranged to adapt the rotational speed of the coupling head 19 and to transmit the rotation of the motor 8 also to the other cutting units 3.

(13) The first coupling member 18 has an axis of rotation 24. As shown in FIGS. 4 to 6, the coupling head 19, seen in the direction of the axis of rotation 24, has a substantially triangular shape, which is rotationally symmetrical through 120. The coupling head 19 has three curved drive surfaces 25 between which curved connecting surfaces 26 are present. FIG. 3 shows the first coupling member 18 in a cross-section in a plane P1 (i.e. the cross-section III-III in FIG. 6), which comprises the axis of rotation 24 and which is transverse to one of the drive surfaces 25. This plane P1 is also perpendicular to one of the connecting surfaces 26 as a result of the rotational symmetry through 120. In the cross-sectional view of FIG. 3, the drive surface 25 has a curvature with a first radius of curvature R1 whose center M1 lies on the axis of rotation 24. In the same cross-sectional view, the connecting surface 26 has a curvature with a second radius of curvature R2 whose center M2 also lies on the axis of rotation 24 and coincides with the center M1 of the curved drive surface 25. The radius of curvature R2 is larger than the radius of curvature R1 here. The other drive surfaces 25 and connecting surfaces 26 have similar geometries, seen in corresponding cross-sectional views. The centers M1 and M2 may be regarded as the drive center of the coupling head 9. During operation of the shaving apparatus, the cutting unit 3 is capable of pivoting relative to the coupling head 19, wherein M1 and M2 constitute the center of the pivoting movement of the cutting unit. This is shown in FIG. 7. Furthermore, each drive surface 25 of the coupling head 19 has a slight curvature with a relatively large radius of curvature R3 seen in a plane P2 (i.e. the cross-section V-V shown in FIG. 5) perpendicular to the axis of rotation 24, such that R3 is much larger than R1 or R2. The reason for this will be explained below.

(14) FIG. 8 is a bottom view of a preferred embodiment of the second coupling member 16 of the internal cutting member 6 according to the invention. The coupling cavity 21 has a triangular shape, which is rotationally symmetrical through 120, as is the coupling head 19. It is apparent that the coupling head 19 makes contact with the walls of the coupling cavity 21 at three locations. In particular, the three curved drive surfaces 25 of the coupling head 19 bear on three driven surfaces 28 of the second coupling member 16 in three points of contact. The large radius of curvature R3 of the drive surfaces 25 of the coupling head 19 ensures that the points of contact of the cooperating drive surfaces 25 and driven surfaces 28 will always lie on the drive surfaces 25, i.e. not on the edges between the drive surfaces 25 and the connecting surfaces 26.

(15) As shown in FIG. 8, the coupling cavity 21 is located in the center of the second coupling member 16. The coupling cavity 21 is connected with three recesses 31 arranged in a star-like geometry, wherein each recess 31 extends in a radial direction with respect to the axis of rotation 24 from the coupling cavity 21. Each recess 31 comprises side wall sections 31a, 31b, wherein side wall section 31a of each recess is flush with a respective one of the driven surfaces 28 of the coupling cavity 21 at the inner portion of the coupling cavity 21. The side wall sections 31a, 31b are not parallel to each other, but rather converge seen in a radially outward direction in relation to the axis of rotation 24. As a result, edges 32a, 32b formed between a bottom surface 40 of the second coupling member 16 and the side wall sections 31a, 31b also converge in said radially outward direction relative to the axis of rotation 24, and the edges 32a, 32b thus form a divergent guidance for the coupling head 19 in a direction towards the coupling cavity 21. Said divergent orientation of the edges 32a, 32b in a direction towards the coupling cavity 21 acts as a non-parallel track for the coupling head 19 in case the coupling head 19 is not aligned relative to the coupling cavity 21 when the coupling head 19 is to be mounted into the coupling cavity 21. In such a case, during connection of the coupling head 19 into the coupling cavity 21, the coupling head 19 will be moved towards the coupling cavity 21 along the divergent edges 32a, 32b acting as non-parallel tracks. It shall be understood that the effect of the coupling head 19 being guided in a radially inward direction towards the coupling cavity 21 is similar to the effect of a marble rolling over two non-parallel tracks, wherein the marble will roll in a direction in which the tracks diverge.

(16) The non-driven side wall section 31b of each recess 31 forms an edge 32b with the bottom surface 40 of the second coupling member 16. The edge 32b is chamfered, resulting in a beveled surface or chamfer on the edge 32b. The chamfered edge 32b further improves guidance of the coupling head 19 towards the coupling cavity 21. As can be seen in FIG. 8, the non-driven side wall sections 31b each have such a chamfered edge 32b over their complete longitudinal extent along the bottom surface 40. In each recess 31, the edge between the opposed side wall section 31a and the bottom surface 40 is not chamfered in the way of the opposite edge 32b, but is rather rectangular with a slight rounding. Further, the driven surfaces 28 each have a chamfered edge 32a at the bottom surface 40. The chamfered edges 32a are each flush with one of the respective chamfered edges 32b. As a result, the chamfered edges 32b provided along the non-driven side wall sections 31b extend into the chamfered edges 32a provided along the driven surfaces 28, but do not extend along the side wall sections 31a which are flush with the driven surface sections 28, as shown in FIG. 8. However, it should be understood that in other embodiments both edges 32a, 32b of each recess 31 may be chamfered along their whole longitudinal extent.

(17) In the embodiment shown in FIG. 8, each side wall section 31a, 31b encloses an angle of 14.5 with a radial line running through the center of the second coupling member 16, resulting in an angle of convergence of each pair of side wall sections 31a, 31b of 29. It should be understood that the angle of convergence of the side wall sections 31a, 31b and of the edges 32a, 32b is preferably in a range of 10-40, more preferably in a range having a lower limit of 15 or 20 or even 25 and an upper limit of 35, 30 or even 25.

(18) FIG. 8 shows the recesses 31 in a mutual orientation which is rotationally symmetric about the middle axis of the second coupling member 16 (or about the axis of rotation 24), and each recess 31 is mirror-symmetric with respect to a symmetry line coinciding with a radius line of the second coupling member 16. It is to be understood that, whereas rotational symmetry of the recesses 31 about the middle axis is preferred, each single recess 31 need not have a mirror-symmetrical design with respect to a radius line, but may be non-symmetrical in other embodiments.

(19) Generally, the converging edges 32a, 32b may be straight, but other edge designs, like curved edges or edges with multiple straight edge sections in an angular arrangement with respect to each other, may be preferable in other embodiments. It is to be understood that, accordingly, the side wall section, which forms the edge with the bottom surface, may be planar, curved or may comprise a plurality of planar surface sections in a mutually angular arrangement.

(20) The coupling cavity 21 is closed at its bottom, i.e. at the upper end of the second coupling member 16 in the center region, by a bearing surface 30. The recesses 31 are formed as through-holes through the second coupling member 16 and thus each allow for the escape of hairs from the upper to the lower side of the second coupling member 16 during operation.

(21) The coupling head 19 has an upper surface, which is designed as an axial spherical bearing surface 29 (see FIGS. 3 and 4). The spherical bearing surface 29 co-operates with the bearing surface 30 of the second coupling member 16 (see FIG. 2) situated in the center of the coupling cavity 21. The spherical bearing surface 29 has a curvature with a radius of curvature R4 whose center M4 lies on the axis of rotation 24 (see FIG. 3). The radius of curvature R4 is larger than the radii of curvature R1 and R2, viewed in the direction of the axis of rotation 24. The center M4 thus lies below the drive center M1, M2, which results in a greater stability.

(22) The through-holes in the second coupling member 16 provided by the recesses 31 prevent contamination, especially by cut-off hairs and skin grease, from entering the coupling cavity 21. Such contamination could hamper the insertion of the coupling head 19 into the coupling cavity 21. Cut-off hairs and skin grease are sucked through the recesses 31 during operation of the shaving apparatus and will not enter between the first and second coupling members 18, 16. The second coupling member 16 is further provided with sloping inlet surfaces 32 (see also FIG. 2) which facilitate the introduction of the coupling head 19 into the coupling cavity 21 when the holder 2 with the cutting unit 3 is placed on the housing 1.

(23) Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

(24) In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality.

(25) Any reference signs in the claims should not be construed as limiting the scope.