Personal care device

Abstract

A personal care device comprising a main housing, a hair-cutting module displaceable with respect to the main housing against spring force in a direction parallel to a main axis, and a sensor comprising a first sensor unit connected to the main housing and a second sensor unit connected to the hair-cutting module. The hair cutting module is also tiltable in directions relative to the main housing. By measuring average displacement of the hair cutting module at multiple locations, the sensor is sensitive only to displacement parallel to the main axis. The sensor measures such displacement and determines the force needed to effect such displacement. If the force is larger than a predetermined value, a warning signal will be produced.

Claims

1. A personal care device comprising: a main housing disposed around a main axis; a hair-cutting module that is displaceable relative to the main housing in a direction parallel to the main axis; a spring arrangement disposed in the device for applying a predetermined spring force against displacement of the hair-cutting module in said direction parallel to the main axis; a sensor arrangement comprising a first sensor unit connected to the main housing and a second sensor unit connected to the hair-cutting module for movement with said module; the hair-cutting module also being rotatable relative to the main housing about at least one tilt axis extending perpendicularly to the main axis and against said predetermined spring force; the first sensor unit including first and second sensory portions disposed at respective first and second locations relative to the main housing; the second sensor unit including third and fourth sensory portions disposed at respective third and fourth locations relative to the hair-cutting module that are opposite to the first and second locations, respectively; said first and second sensor units being adapted to move relative to each other during tilting of the hair-cutting module about the at least one tilt axis such that distances between the first and third sensory portions and between the second and fourth sensory portions will change, but the average distances between the first and second sensor units will remain unchanged; and the sensor arrangement being adapted to be insensitive to said unchanging average distances during tilting but to be sensitive to said changes in displacement of the hair-cutting module relative to the main housing in the direction parallel to the main axis.

2. A personal care device according to claim 1 where, with respect to a plane extending through the main axis and the tilt axis, the first and the third location are located on a first side of said plane whilst the second and the fourth location are partly located in said plane or on a second side of said plane.

3. A personal care device according to claim 1 where the hair-cutting module is tiltable with respect to the main housing about two tilt axes extending perpendicularly to each other.

4. A personal care device according to claim 1 where the first sensor unit and the second sensor unit are arranged symmetrically around the main axis.

5. A personal care device according to claim 1 where the hair-cutting module comprises a number of cutting units, each cutting unit being provided with an external cutting element and an internal cutting element being rotatable about a rotation axis with respect to the external cutting element, wherein the rotation axes of the cutting units are located symmetrically around the main axis and each enclose an angle between 0 degrees and 15 degrees with the main axis.

6. A personal care device according to claim 5 where the hair-cutting module is connected to the main housing via a central shaft member which accommodates a main driving axle for commonly driving the internal cutting elements of the cutting units, and wherein the sensor arrangement is arranged symmetrically around said main driving axle.

7. A personal care device according to claim 1, wherein the first sensor unit or the second sensor unit comprises a ring-shaped coil and the other of the sensor units comprises a plate influencing a magnetic field of the ring-shaped coil by a displacement of the second sensor unit with respect to the first sensor unit in a direction parallel to the main axis.

8. A personal care device according to claim 1, wherein the first sensor unit or the second sensor unit comprises at least three Hall-sensor elements arranged at predetermined different locations around the main axis, and the other of the sensor units comprises at least three magnets, each magnet being arranged opposite a respective one of the Hall-sensor elements, seen in directions parallel to the main axis.

9. A personal care device according to claim 8, wherein the Hall-sensor elements as well as the magnets are arranged at regular intervals around the main axis.

10. A personal care device according to claim 1, wherein the hair cutting module comprises an intermediate part, which is provided with the second sensor unit, and a first hair cutting part, which is detachably connectable to the intermediate part, whilst the personal care device comprises a second hair cutting part which is different from the first hair cutting part, wherein by connecting the first hair cutting part to the intermediate part the second sensor unit is displaced into a reference position relative to the first sensor unit, or obtains a geometry or a material characteristic which is different from, respectively, a reference position, a geometry or a material characteristic obtained by connecting the second hair cutting part to the intermediate part.

11. A personal care device according to claim 10, wherein the second sensor unit is displaced against spring force with respect to the intermediate part by connecting the first hair cutting part to the intermediate part.

12. A personal care device according to claim 10, wherein the first hair cutting part is a hair shaving part and the second hair cutting part is a hair trimming or brushing part.

13. A personal care device according to claim 1 where a distance between the first and second locations is at least 25% of a distance between the first and the third locations.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective schematic view of a personal care device according to the invention,

(2) FIG. 2 is a side view of the personal care device according to the invention,

(3) FIG. 3 is a schematic cross section of a first embodiment of the personal care device as shown in FIGS. 1 and 2,

(4) FIG. 4 is a schematic cross section of a second embodiment of the personal care device as shown in FIGS. 1 and 2,

(5) FIGS. 5 and 6 are detailed top and bottom views of the personal care device as shown in FIG. 4,

(6) FIGS. 7A and 7B are schematic top and side views of the sensor of the personal care device as shown in FIG. 4,

(7) FIG. 8 is a schematic cross section of a third embodiment of the personal care device as shown in FIGS. 1 and 2,

(8) FIGS. 9-11 are views of the personal care device as shown in FIG. 8, obtained following respectively an axial displacement, tilt displacement and combined axial and tilt displacement of the hair-cutting module with respect to the main housing,

(9) FIG. 12 is a schematic cross section of a fourth embodiment of the personal care device as shown in FIGS. 1 and 2,

(10) FIG. 13 is a schematic cross section of a fifth embodiment of the personal care device as shown in FIGS. 1 and 2, without a hair cutting part,

(11) FIG. 14 is a schematic cross section of the personal care device as shown in FIG. 13, with a first hair cutting part,

(12) FIG. 15 is a schematic cross section of the personal care device as shown in FIG. 13, with a second hair cutting part,

(13) FIG. 16 is a graph showing the operating windows of the sensor of the personal care device as shown in FIG. 13, with the first and the second hair cutting part.

(14) In the drawings, like reference numerals refer to like elements.

DETAILED DESCRIPTION OF EMBODIMENTS

(15) FIGS. 1 and 2 show a personal care device according to the invention. The personal care device as shown in FIGS. 1 and 2 is a shaver 1 comprising a main housing 2, which is suitable to be held by a user of the shaver. In FIG. 1, for the sake of simplicity, the main housing 2 is only diagrammatically shown in view of the fact that within the scope of the present invention, the main housing 2 may have any suitable design. In FIG. 2 a possible design of the main housing 2 is shown. The shaver 1 further comprises a hair-cutting module 3, which is suitable to contact an area of skin having hairs to be shaved off and which can suitably be moved with respect to this area. The hair-cutting module 3 is connected to the main housing 2 through a central shaft member 4, wherein the connection of the hair-cutting module 3 to the main housing 2 may be detachable. Cross-sectional dimensions of the central shaft member 4 are considerably smaller than the cross-sectional dimensions of the hair-cutting module 3, and the hair-cutting module 3 is positioned at a certain distance from a top portion 5 of the main housing 2. Consequently, the connection between the main housing 2 and the hair-cutting module 3 has a slim appearance, wherein the hair-cutting module 3 has an elevated position with respect to the main housing 2. Due to this, when a user performs a shaving action by using the shaver 1, he may have a clear side view of the hair-cutting module 3.

(16) The hair-cutting module 3 comprises three cutting units 6, which are arranged in a triangle formation. Within the scope of the present invention, the number of cutting units 6 may also be two or more than three. For the sake of completeness, it is noted that each of the cutting units 6 may be arranged so as to be movable to a certain extent to facilitate each of them in following a contour of an area of skin to be shaved. For example, the cutting units 6 may be pivotable, to a limited extent, with respect to the central shaft member 4. Each cutting unit 6 comprises a cap-shaped external cutting element 7 which is arranged at a top side of the cutting unit 6, and which has a plurality of openings 8 for letting through hairs to be shaved off. The cap-shaped external cutting element 7 is pivotably connected to a base portion 9 of the cutting unit 6. Right underneath the cap-shaped external cutting element 7, on the inside of the cutting unit 6, an internal cutting element (not visible) is rotatably arranged. During operation, a central portion of the internal cutting element is pressed against the cap-shaped external cutting element 7 under spring force.

(17) The internal cutting elements of the cutting unit 6 are driven, via gear wheels, by a main driving axle extending from a motor in the main housing 2 through the central shaft member 4 into the hair cutting module 3

(18) The shaver 1 described so far is known from WO2011055323A1 and WO200810139A1, in the name of the current applicant.

(19) FIG. 3 is a schematic cross section of a first embodiment of the shaver 1. The central shaft member 4 of the hair-cutting module 3 is connected to the main housing 2 by means of a spring 10. The central shaft 4 extends parallel to a main axis 11. The main axis 11 extends in Z-direction. Due to the spring 10, the hair-cutting module 3 is displaceable with respect to the main housing 2 against spring force of the spring 10 along the main axis 11. Furthermore, due to the spring 10, the hair-cutting module 3 is displaceable with respect to the main housing 2 against spring force of the spring 10 in tilt directions R1, R2 about two tilt axes 12, 13. The tilt axes 12, 13 extend in X-direction and Y-direction, respectively. The X, Y, Z-directions extend perpendicularly to each other. By displacing the hair-cutting module 3 with respect to the main housing 2, the central shaft member 4 of the hair-cutting module 3 is partly moved into a space 14 of the main housing 2. The spring 10 is preferably stiff along the X-axis, along the Y-axis and in a pivot direction about the Z-axis.

(20) The shaver 1 according to the invention comprises a sensor 15 located between the main housing 2 and the hair-cutting module 3. The sensor 15 comprises a cylindrical-shaped first sensor unit 16 connected to the main housing 2 and a cylindrical-shaped second sensor unit 17 connected to the hair-cutting module 3. The sensor units 16, 17 are located symmetrically around the main axis 11.

(21) Due to this shape of the sensor units 16, 17, each location of the first sensor unit 16 with respect to the main housing 2 is located adjacent and opposite a location of the second sensor unit 17 with respect to the hair cutting module 3.

(22) Due to this shape of the sensor units 16, 17, the first sensor unit 16 as well as the second sensor unit 17 are partly located on a left side of a first plane extending through the Y-Z-axes and are partly located in the right side of said first plane. The first plane extends perpendicularly to the plane of FIG. 3.

(23) Due to this shape of the sensor units 16, 17, the first sensor unit 16 as well as the second sensor unit 17 are also partly located on a front side of a second plane extending through the X-Z-axes and are partly located in the back side of said second plane. The second plane extends parallel to the plane of FIG. 3.

(24) The internal cutting elements of the cutting units 6 of the hair-cutting module 3 are rotatable with respect to the cap-shaped external cutting elements 7 about rotation axes 18, 19 with respect to the external cutting element. A third rotation axis is located behind the main axis 11. The three rotation axes are located symmetrically around the main axis 11, wherein the three rotation axes extend at an angle between 0 degrees and 15 degrees with respect to the main axis 11.

(25) During shaving using the shaver 1, the user presses the cutting units 6 against the skin with a certain force, whereby the skin presses against the hair-cutting module 3 with a normal force Fn. Due to said normal force Fn extending perpendicularly to the skin and forces Fx, Fy extending parallel to the skin and being caused by friction between the cutting units 6 and the skin when the cutting units 6 are moved over the skin, the hair-cutting module 3 is being moved against the spring force of the spring 10 in axial direction and in the tilt directions R1, R2.

(26) The sensor 15 measures the average displacement of the hair-cutting module 3 at multiple locations, each at a fixed radial distance from the main axis 11. By measuring this average displacement, the sensor 15 is only sensitive to displacement in the Z-direction, while rotations about the X- and Y-axes are cancelled out.

(27) There is a direct relationship between the force Fn due to which the cutting module 3 is depressed against spring force of the spring 10 relative to the main housing 2 and the axial displacement. From the measured displacements and the known stiffness properties of the spring 10, the normal force Fn on the skin can be calculated by means of a processor (not shown). If the axial displacement and thus the normal force Fn is larger than a predetermined value, a warning signal will be produced by an alarm (not shown) located in the main housing 2.

(28) FIGS. 4-7B show a second embodiment of the shaver 1. The shaver 1 differs from the shaver as shown in FIG. 3 by the configuration of the sensor only. The sensor 25 of the shaver 1 as shown in the FIGS. 4-7B comprises a first sensor unit with at least three Hall-sensor units H0, H1, H2 located at regular intervals around the main axis 11 and at the same radial distance from the main axis 11. The three Hall-sensor units H0, H1, H2 are mounted at a distance from the spring 10 on a bottom 26 of the space 14. The sensor 25 also comprises a second sensor unit with three magnets M0, M1, M2, each magnet M0, M1, M2 being located opposite one of the three Hall-sensor units H0, H1, H2. The three magnets M0, M1, M2 are mounted on a ring 27 connected to the central shaft member 4 of the hair-cutting module 3. The Hall-sensor units H0, H1 are located at first and second locations adjacent to and opposite magnets M0, M1 located at third and fourth locations, whilst the third Hall-sensor unit H2 and third magnet M2 are located at fifth and sixth locations, respectively. The spring 10 comprises three spring parts 28 connected with one end to the main housing 2 and with another end to the ring 27. Through a central opening 29 of the ring 27, a driving axle 4 for driving the rotation axes of the cutting units 6 extends. The driving axle 4 is located inside the central shaft member 4.

(29) If the shaver 1 is not being used, the magnets M0, M1, M2 are situated in a plane extending parallel to a plane wherein the Hall-sensor units H0, H1, H2 are situated.

(30) As can be seen in FIG. 7A, the magnet M0 and the Hall-sensor unit H0 are located on the right side of a plane through the Y-Z-axis, the magnet M1 and the Hall-sensor unit H1 are located in the plane through the Y-Z-axis, whilst the magnet M2 and the Hall-sensor unit H2 are located on the left side of the plane through the Y-Z-axis. Furthermore, the magnets M0, M2 and the Hall-sensor unit H0, H2 are located above a plane through the X-Z-axis, whilst the magnet M1 and the Hall-sensor unit H1 are located below the plane through the X-Z-axis. Due to said specific location of the magnets M0, M1, M2 and the Hall-sensor units H0, H1, H2, the exact displacement of the hair-cutting module 3 in the R1, R2, Z-directions can be measured, as will be explained below.

(31) The magnets M0, M1, M2 and the Hall-sensor units H0, H1, H2 are located 120 degrees from each other.

(32) By each combination of one of the magnets M0, M1, M2 and one of the Hall-sensor units H0, H1, H2, the distances between the first and third location, the second and fourth location and the fifth and sixth location are measured. The measured distance between the third location of the magnet M0 and the first location of the Hall-sensor unit H0 is h0, the measured distance between the fourth location of the magnet M1 and the second location of the Hall-sensor unit H1 is h1 and the measured distance between the sixth location of the magnet M2 and the fifth location of the Hall-sensor unit H2 is h2.

(33) From the measured distances h0, h1, h2, the radius r and the angle of 120 degrees, the displacement Pz of the centre C of the hair-cutting module 3 can be calculated as follows:
h02=(h0+h2)/2; average distance of the magnets M0 and M2 to the Hall-sensor units H0 and H2
Pz=(h0+h1+h2)/3
?X=arcsin((Pz?h1)/r)
?Y=arcsin((h2?h0)/(r*.sup.?{square root over (3)}))
The stiffness properties of the spring 10 are known, so that based on the known stiffness properties cz of the spring 10 and the value of the displacement Pz, the normal force Fn can be calculated Fn=cz*Pz.

(34) If the normal force Fn is larger than a predetermined value a warning signal will be given.

(35) In the same manner, based on known stiffness properties cx, cy of the spring 10 against rotation about the x-axis and y-axis respectively, the forces Fx and Fy can be calculated Fx=cx.Math.?X and Fy=cy.Math.?Y. If the forces Fx, Fy are larger than a predetermined value, another warning signal will be given. In such a case, the user will be advised to use a gel to reduce the friction forces Fx, Fy.

(36) FIGS. 8-11 show a third embodiment of the shaver 1. The shaver 1 differs from the shavers as shown in FIGS. 3 and 4-7B by the configuration of the sensor only. The sensor 35 of the shaver as shown in FIGS. 8-11 comprises a first sensor unit with a ring-shaped coil 36 located symmetrically about the main axis 11. The ring-shaped coil 36 is mounted at a distance from the spring 10 on the bottom 26 of the space 14. The sensor 35 also comprises a second sensor unit with a ring-shaped metal plate 37 located symmetrically about the main axis 11. The metal plate functions like a short-circuited coil with only one winding. The ring-shaped metal plate 37 is connected to the central shaft member 4 of the hair-cutting module 3.

(37) Movement of the metal plate 37 with respect to the coil 36 influences the inductance of the coil 36.

(38) If the hair-cutting module 3 is only displaced along the main axis 11, as shown in FIG. 9, the hair-cutting module 3 is moved from the position as shown in dotted lines to the position shown in full lines. Along the complete circumference of the coil, the partial contribution to the coil inductance will change in the same manner. The change in inductance of the coil 36 is a measure of the displacement of the hair-cutting module 3 and thus of the force Fn.

(39) If the hair-cutting module 3 is only tilted about an axis extending perpendicularly to the main axis 11, as shown in FIG. 10, the hair-cutting module 3 is moved from the position as shown in dotted lines to the position shown in full lines. On the left side of FIG. 10, the distance between the coil 36 and the plate 37 will increase, whilst on the right side of FIG. 10, the distance between the coil 36 and the plate 37 will decrease. However, the average distance between the coil 36 and the plate 37 will remain the same, so the inductance of the coil 36 will not be changed.

(40) If the hair-cutting module 3 is displaced along the main axis 11 as well as tilted about an axis extending perpendicularly to the main axis 11, as shown in FIG. 11, the hair-cutting module 3 is moved from the position as shown in dotted lines to the position shown in full lines.

(41) The change in inductance of the coil 36 will only be caused due to the displacement along the main axis 11.

(42) It is also possible to use a plate of an electrically isolating material with a high magnetic permeability. Therefore, the plate can be made of ferrite. Also such a plate will influence the inductance of the coil 36.

(43) The sensors as described above have the advantages that: the sensor has a very low cost; the sensor can be placed inside the shaver such that no wires to the outside of the shaver are needed. This improves the water tightness of the shaver; the sensor can measure static displacements because it has a low drift over time; the sensor has a very long lifetime since it is not mechanically coupled, and hence it is free of wear.

(44) FIG. 12 shows a fourth embodiment of the shaver 1. The shaver 1 differs from the shavers as shown in FIGS. 3, 4-7B and 8-11 by the configuration of the sensor only. The sensor 45 is suitable for the measurement of the average displacement Pz of the hair-cutting module 3 along the main axis 11, wherein the sensor is located at a distance from the main axis 11 to be able to allow a driving axle, used for driving the rotation axes of the cutting units, to extend centrally through the sensor. Such a sensor 45 may comprise for example piezo-elements, force-sensitive resistors, capacitive distance sensors or strain gauges.

(45) It is also possible that magnets M0, M1, M2 are connected to the main housing and the Hall-sensor units H0, H1, H2 are connected to the hair-cutting module 3.

(46) It is also possible that the hair-cutting module 3 is only tiltable about one single tilt axis.

(47) FIGS. 13-15 show a fifth embodiment of the personal care device 51 according to the invention. The personal care device differs from the shaver 1 as shown in FIGS. 8-11 by the configuration of the hair-cutting module 3. Like the shaver 1 as shown in FIGS. 8-11, the sensor 35 of the personal care device 51 comprises a first sensor unit with a ring-shaped coil 36 located symmetrically about the main axis 11. The sensor 35 also comprises a second sensor unit with a ring-shaped metal plate 37 located symmetrically about the main axis 11. The metal plate functions like a short-circuited coil with only one winding. Movement of the metal plate 37 with respect to the coil 36 influences the inductance of the coil 36. In the position as shown in FIG. 13, the metal plate 37 is located at a distance d0 from the coil 36. The personal care device 51 differs from the shaver 1 as shown in FIGS. 8-11 in that the hair-cutting module 3 comprises an intermediate part 52 with a tubular housing 53, a central opening 54 in the housing 53 and an element 55 being able to hold a hair cutting part 56, 57 in the opening 54. The intermediate part 52 also comprises a number of first springs 58. Each spring 58 comprises a horizontally extending part 59 connected to the metal plate 37, an inclined part 60 connected to the horizontally extending part 59 and a vertically extending part 61 connected to the inclined part 60. The vertically extending part 61 can slide in a direction parallel to the main axis 11 with respect to the housing 53.

(48) The intermediate part 52 also comprises a number of second springs 62 connected with one end 63 to the tubular housing 53 and with another end 64 to the metal plate 37. The second springs 62 pull the metal plate 37 against the tubular housing 53. The cumulative stiffness of the second springs 62 is less than the cumulative stiffness of the first springs 58. Furthermore, the intermediate part 52 comprises hook-shaped stopping elements 65 limiting the movement of the metal plate 37 in a direction away from the tubular housing 53.

(49) FIG. 14 shows the personal care device 51 with a first hair cutting part 56 being detachably connected to the intermediate part 52. The first hair cutting part 56 may comprise a base portion 9 and cutting units 6 (not shown in FIG. 14), like the shaver 1 as shown in FIGS. 1 and 2. The hair cutting part 56 comprises a tubular part 66 having an end portion 67. When the tubular part 66 of the first hair cutting part 56 is inserted into the opening 54 of the intermediate part 52, it is kept in this position by means of element 55. The element 55 may comprise a spring being able to firmly hold the tubular part 62 but allowing detaching of the first hair cutting part 56 when a user firmly pulls at the first hair cutting part 56. Such a connection is known in personal care devices and will not be further explained. When the tubular part 62 of the first hair cutting part 56 is inserted into the opening 54 of the intermediate part 52, the end portion 67 will be pressed against the vertically extending parts 61 of the springs 58, due to which forces the vertically extending parts 61 of the springs 58 will be moved in a direction parallel to the main axis 11 and will move the metal plate 37 towards the coil 36 over a distance ds. This position of the metal plate 37 is the first reference position and when the personal care device 51 is in use, the metal plate 37 will be moved further towards the coil 36 when the cutting units 6 are pressed against the skin of a user.

(50) FIG. 15 shows the personal care device 51 with a second hair cutting part 57 being detachably connected to the intermediate part 52. The second hair cutting part 57 may comprise a trimmer or brush (not shown in FIG. 15). The hair cutting part 57 comprises a tubular part 68 having an end portion 69. The tubular part 68 of the second hair cutting part 57 is connected to the intermediate part 52 in the same manner as the tubular part 66 of the first hair cutting part 56. However, when the tubular part 68 of the second hair cutting part 57 is inserted into the opening 54 of the intermediate part 52, the end portion 69 will be located at a distance d2 from the vertically extending parts 61 of the springs 58 and will not be pressed against the vertically extending parts 61 of the springs 58. The distance d2 between the metal plate 37 and the coil 36 is the same as the distance d0 in FIG. 13, wherein no hair cutting part is connected to the intermediate part 52. This position of the metal plate 37 is the second reference position and when the personal care device 51 is in use, the metal plate 37 will be moved further towards the coil 36 when the personal care device is pressed against the skin of a user.

(51) FIG. 16 shows a graph in which the distance d between the metal plate 37 and the coil 36 is plotted on the x-axis and the corresponding value for the inductance is plotted on the y-axis. In this graph, the first reference position is at a distance d1, which is smaller than the distance d2 of the second reference position. When the personal care device 51 is in use, the distance d will vary in the grey area 70, 71, respectively.

(52) The respective inductance values will vary over an operating window W1, W2 respectively.

(53) By measuring the inductance it can be determined whether the first or the second hair cutting part 56, 57 is connected to the intermediate part 52.

(54) The same change in operating window can also be achieved by means of an offset of the electric resistance of the metal plate 37, for example by an embodiment in which the metal plate 37 has a slot which is short-circuited when the first hair cutting part with a shaving unit is placed. The principle of changing the operating window of the sensor 35 can also be applied on other force-sensing principles e.g. hall sensor, strain gauge or piezo-based force sensors.

(55) The personal care device can also be a vibratory shaver, a trimmer, a grooming device or other kind of cutting device.

(56) The first, second, third and fourth locations can also be located on the same side of a plane through the main axis and tilt axis if the distance from the first location to the plane differs from the distance from the second location to the plane. The main feature is that the distance change due to the tilting movement is different between the first and third location and between the second and fourth location.

(57) The person skilled in the art will realize that the present invention is by no means limited to the preferred embodiments. 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.

(58) 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. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

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

LIST OF REFERENCE SIGNS

(60) 1 shaver 2 main housing 3 hair-cutting module 4 central shaft member 4 driving axle 5 top portion 6 cutting unit 7 external cutting element 8 opening 9 base portion 10 spring 11 main axis 12 tilt axis 13 tilt axis 14 space 15 sensor 16 first sensor unit 17 second sensor unit 18 rotation axis 19 rotation axis 25 sensor 26 bottom 27 ring 28 spring part 29 central opening 35 sensor 36 coil 37 metal plate 45 sensor 51 personal care device 52 intermediate part 53 tubular housing 54 central opening 55 element 56 hair cutting part 57 hair cutting part 58 first spring 59 horizontally extending part 60 inclined part 61 vertically extending part 62 second spring 63 end 64 end 65 tubular part 66 tubular part 67 end portion 68 tubular part 69 end portion 70 grey area 71 grey area C centre Fn force Fn H0 Hall-sensor unit H1 Hall-sensor unit H2 Hall-sensor unit M0 magnet M1 magnet M2 magnet Pz displacement r radius R1 tilt direction R1 R2 tilt direction R2 W1 operating window W2 operating window Z direction ? distance