Patent Application
20220184830
The invention relates to a shaver according to the introductory portion of claim 1. Such a shaver is known from WO2015/025064.
During shaving, a user generally tries to achieve a clean shave in a short time while avoiding skin irritation and skin injury. Skin irritation and injury occur when the hair-cutting member comes into contact with the skin too intensively, which occurs particularly when the user presses the hair-cutting member against the skin with excessive force. This can occur during use of manual wet-shavers as well as during use of electric shavers (razors). In particular users who have recently switched from one system to the other or inexperienced users tend to have difficulties in pressing the shaving head against the skin with a pressure in a range of suitable pressures while following the shape of the body part to be shaved. The range of suitable pressures may also vary with skin thickness.
U.S. Pat. No. 5,983,502A discloses a shaver in which pressure against the skin is measured by measuring the extent to which hair-cutting units (sometimes referred to as shaving heads) are pressed into the hair-cutting body. If a sensor signals a too large inward displacement of the hair-cutting units, a signal warning the user that a too high shaving pressure is exerted is generated. The sensor of each hair-cutting unit comprises annular permanent magnets, which are secured to a coupling pin, and a Hall-sensor, which is disposed underneath the magnet and which is secured in the main body.
However, inward displacement of the cutting units is limited and to a large extent used for accommodating the orientations of the cutting units to the curvature of the skin surface being shaved by tilting of cutting units relative to the hair-cutting body. Thus, indication of exerted pressure is also affected by tilting of the hair-cutting units while accommodating to the curvature of the skin being shaved and the range of displacement available for pressure force measurement is reduced by the range of displacement required for allowing tilting.
In the shaver according to WO2015/025064, this problem has been solved by measuring shaving pressure in accordance with displacement and tilting of the hair-cutting body (which includes the cutting units) relative to the main body. This allows the cutting units to tilt and be pressed-in while accommodating to the shape of the skin without interfering with shaving pressure measurement. However, a shaver with shaving pressure signalization according to WO2015/025064 is relatively complicated and manufacturing is costly. Also, the suspension is relatively large in radial directions.
It is an object of the present invention to provide a shaver that provides accurate indications of shaving pressure but is of a more simple and compact construction.
According to the invention, this object is achieved by providing a shaver according to the claims.
Because, in addition to a resilient member, an anti-tilting guide is provided for guiding at least the sensor unit carrier with respect to the main body against tilting about at least the y-axis perpendicular to the x-axis and the z-axis, tilting that strongly influences the distance between the first sensor unit and the second sensor unit in z-direction is at least substantially reduced. Thus, displacement of the shaving unit, and accordingly the exerted force that causes the applied shaving pressure, can be measured, with no or very little influence by tilting of the shaving unit, by one simple sensor that only needs to be arranged and configured for measuring a distance between the first and second sensor units in the direction of the z-axis and can be conveniently located at some distance in x-direction away from the z-axis, where space is available for accommodating the sensor units, even in a compact shaver.
The anti-tilting guide may allow tilting of the sensor unit carrier about the x-axis perpendicular to the y-axis and to the z-axis and may allow pivoting of the sensor unit carrier about the z-axis. The guiding against tilting generally may allow some play and/or elasticity, so that tilting about the y-axis is substantially reduced by the anti-tilting guide but is not necessarily completely eliminated.
Particular elaborations and embodiments of the invention are set forth in the dependent claims.
Further features, effects and details of the invention appear from the detailed description and the drawings.
The shaving unit 3 has three cutting units 6 (of which only two are visible in
In the present example, the cutting unit carrier 9 is further connected to the main body 2 via a main drive shaft 12 for commonly driving the internal cutting elements 7 of the cutting units 6 via gear wheels (not shown). The main drive shaft 12 is coupled to a motor 13 in the main body 2. A gear wheel 18 on the main drive shaft 12 is engaged by a driving gear wheel 14 on an output drive shaft 19 of the motor 13. The central coupling member 4 engages a coupling member of a central gear wheel (not shown) engaging the gear wheels. While in the present example, the cutting units have internal cutting elements that are in rotating movement when the shaver is in use, the present invention is also applicable to shavers with cutting elements having internal cutting elements that move back and forth linearly between first and second end positions in an oscillating fashion.
For power supply to the motor 13, a battery 42 is provided and is connected to a motor controller 43 that controls power supply to the motor 13 to which the motor controller 43 is connected. The motor controller 43 may be provided with a switch for receiving control input from a user.
The shaving unit 3 is suspended to the main body 2 for displacement from a rest position (as shown) towards the main body 2 along a z-axis oriented transverse to the shaving face 11 to a pushed-in position slightly closer to the main body 2 than the position shown in
The shaving unit may be entirely or partially tiltable relative to the sensor unit carrier to allow easy accommodation of the orientation of the shaving face to the orientation of the skin surface to be shaved. Instead, the shaving unit may be fixed relative to the sensor unit carrier and, instead of being detachable, as in the present example, the shaving unit may be permanently fixed to the sensor unit carrier or integrally formed with the sensor unit carrier. Furthermore, while in this example, the sensor unit carrier 22 is a part of the main body 2, it may instead be a part of the shaving unit.
The sensor 15 has a first sensor unit 16 mounted in a fixed position relative to the main body 2 and a second sensor unit 17 mounted in a fixed position to the sensor unit carrier 22. The first sensor unit 16 and the second sensor unit 17 are offset from the z-axis over a distance d in an x-direction perpendicular to the z-direction. The sensor 15 further has a signal processing unit 20 connected to the first sensor unit 16 and a sound generator 21 connected to an output port of the signal processing unit 20. The sensor 15 is arranged and configured for outputting a signal indicating a distance of the second sensor unit 17 to the first sensor unit 16. In the present example, the first sensor unit 16 is a hall sensor and the second sensor unit 17 is a magnet. Other types of distance sensor units, such as optical sensors or inductive sensors as described in WO2015/025064, are conceivable as well. Instead of or in addition to a sound generator, other signal output means can be used. The generated warning signal can be humanly perceptible or be of a type that is to be received by a receiver of a signal processing device that generates the humanly perceptible warning signal in response to receiving a warning output signal from a signal output transmitter of the shaver, preferably in real time or almost in real time.
As can be seen in
The suspension arms 24, 25, 26, 27 are shaped and dimensioned such that the sensor unit carrier 22 moves out of the rest position to the pushed-in position 22′ (see
Conversely, the measured displacement and accordingly the force exerted in z-direction can also be used to detect exertion of a force that is too small to generate a shaving pressure that is high enough to achieve a clean shave. In response to a too low shaving pressure, a second warning signal can be generated to warn the user that more pressure should be exerted if a clean shave is to be achieved.
In the present example, the second (or first) one of each pair of suspension arms 24, 25 and 26, 27 constitutes an anti-tilting guide for guiding the sensor unit carrier 22 with respect to the main body 2 against tilting about an y-axis perpendicular to the x-axis and the z-axis during movement with the shaving unit 3 between the rest position and the pushed-in position 22′ along the z-axis. Each pair of suspension arms 24, 25 and 26, 27 provides guidance with a high degree of stiffness against tilting about axes in y-direction.
Since tilting of the sensor unit carrier 22 about the y-axis is substantially reduced, disturbance of the distance between the first sensor unit 16 and the second sensor unit 17 by tilting is substantially reduced. Because the first sensor unit 16 and the second sensor unit 17 are offset over a distance d in an x-direction from the z-axis, tilting of the sensor unit carrier 22 about the y-axis would cause the second sensor unit 17 to move in mainly the z-direction, so that virtually the full movement of the second sensor unit 17 due to such tilting would be in the z-direction and thus in the direction in which the distance between the first sensor unit 16 and the second sensor unit 17 is measured. By substantially reducing tilting about the y-axis, such a large influence of the tilting on the distance between the first sensor unit 16 and the second sensor unit 17 is avoided.
If for instance the stiffness of the resilient members in z-direction is such that the ratio between the force exerted in z-direction from the rest position towards the pushed-in position and displacement in that direction is between 10 and 16 N/mm and/or such that the force needed for fully pressing the cutting unit carrier 9 towards the pressed-in position is between 4 and 10 N, the overall stiffness against tilting about the y-axis achieved in the presence of the anti-tilting guide is preferably such that a ratio between a friction force exerted onto the shaving face 11 and displacement of the second sensor unit 17 in the z-direction due to tilting about the y-axis is more than 15 N/mm and more preferably more than 20 N/mm.
Preferably, the cutting unit carrier 9 carrying the hair-cutting units 6 is tiltable relative to the sensor unit carrier 22 so as to allow tilting of the hair-cutting units 6 and the shaving face 11 relative to the sensor unit carrier 22 without causing displacement of the sensor unit carrier 22 relative to the main body 2 along the z-axis. Thus, tilting of the hair-cutting units 6 to accommodate the orientation of the shaving face 11 to the orientation of the skin being shaved can be achieved without significantly influencing the shaving pressure reading in the form of the signal outputted by the first sensor unit 16 to the signal processing unit 20.
The main drive shaft 12 has an axis of rotation extending along the z-axis centrally between the cutting units 6. Thus, rotation driven by the motor 13 can be evenly distributed to the cutting units 6 in a simple manner. Furthermore, by arranging the main drive shaft 12 centrally along the z-axis of the shaving unit 3, the cutting unit carrier 9 and the sensor unit carrier 22, the main drive shaft 12 is conveniently extends centrally through these parts while the z-axis also extends centrally between the cutting units 6. Thus, a shaving pressure evenly distributed over the cutting units 6 is exerted along the z-axis and therefore does not result in a bending moment being exerted about the z-axis. In practice, the resultant force of the aggregated shaving pressure is exerted along a line that will move around in an area around the central z-axis, so that, with the z-axis centrally between the cutting units 6, also the maximum bending moments that are exerted are kept to a minimum.
In the present example, first suspension arms 24, 26 are attached to the main body 2 at first locations 31, 35 and attached to the sensor unit carrier 22 at second locations 32, 36. The first suspension arms 24, 26 each extend between the first locations 31, 35 and the second locations 32, 36. In this suspension, the anti-tilting guide is provided in a very effective and in principle friction free manner by second suspension arms 25, 27 attached to the main body 2 at third locations 33 (one location not visible in any of the drawings) and attached to the sensor unit carrier 22 at fourth locations 34, 38. Also the second suspension arms 25, 27 extend between the third locations 33 and the fourth locations 34, 38. All the suspension arms are elastically deformable, more in particular bendable, in planes parallel to the z-axis.
The first and third locations 31, 35 and 33 are mutually spaced over a first distance having at least a component in a direction parallel to the z-axis. The second and fourth locations 32, 36 and 34, 38 are mutually spaced over a second distance also having at least a component in a direction parallel to the z-axis. The component in the direction parallel to the z-axis of the first distance is of a length identical to the length of the component in the direction parallel to the z-axis of the second distance. Thus, a suspension of the sensor unit carrier 22 is obtained that is flexible in z-direction, but very stiff against tilting about the y-axis and also stiff enough against tilting about the x-axis and pivoting about the z-axis. Although tilting about the x-axis and pivoting about the z-axis influence the distance between the first sensor unit 16 and the second sensor unit 17 to a far lesser extent than tilting about the y-axis, stiffness against such tilting and pivoting is also advantageous for avoiding disturbance of the measurement of shaving pressure in the z-direction.
In the present example, the suspension includes two of the first suspension arms 24, 26 and two of the second suspension arms 25, 27. Providing at least two of the first suspension arms 24, 26 or at least two of the second suspension arms 25, 27, is advantageous to further counteract tilting and pivoting about the z-axis in particular if relatively slender suspension arms are provided in view of limited space available adjacent to the sensor unit carrier 22.
Furthermore, the two first suspension arms 24, 26 as well as the two second suspension arms 25, 27 are located on opposite sides of a plane defined by the x- and z-axes. Thus, a generally symmetrical arrangement of the suspension arms 24, 26 and 25, 27 is obtained in which the two first suspension arms 24, 26 as well as the two second suspension arms 25, 27 can be arranged far apart yet closely along the cutting unit carrier 9.
For obtaining further guidance against tilting in a compact construction, the two first suspension arms 24, 26 as well as the two second suspension arms 25, 27 are interconnected by a bridge 37 fixedly connected with the interconnected pair of suspension arms 24, 26 and 25, 27. This further increases stiffness of the combined suspension arms against tilting.
The two first suspension arms 24, 26 as well as the two second suspension arms 25, 27 diverge towards or away from a plane defined by the y- and z axes, so that the suspension is also stiff against translational displacements in y-direction transverse to the z-axis.
For achieving a particularly high stiffness against tilting about the y-axis with a compact construction, the first locations 31, 35 and the third locations 33, where the suspension arms 24-27 are attached to the main body 2, are positioned on a common side of a plane defined by y- and z-axes, so that the suspension arms 24, 25 and 26, 27 of each pair and the elements 22, 28 and 29 to which these suspension arms are connected generally form a parallelogram in a plane in z-direction and, generally, x-direction and thus provide a high degree of stiffness against tilting. The distance between the suspension arms 24, 25 and 26, 27 can for instance be 5 to 10 mm.
For particularly accurate guidance in z-direction, it is furthermore advantageous that the first locations 31, 35 and third locations 33, where the suspension arms 24-27 are attached to the main body 2, are positioned in a plane parallel to the plane defined by the y- and z-axes.
In the present example, guidance against tilting is achieved in a particularly simple manner and without play in the suspension, because the first and second suspension arms 24-27 are provided in the form of flat leaf springs each having a length in a direction from the first location 31, 35 to the second location 34, 36 or from the third location 33 to the fourth location 34, 38 where the suspension arms 24-27 are fixedly attached and a width in a direction parallel to the y-axis. These effects can be achieved to a lesser extent (for individual arms only) by only providing one or more of the suspension arms 24-27 in the form of such a leaf spring.
The leaf springs are preferably relatively flexible for allowing movement of the sensor unit carrier 22 in z-direction, while being stiff enough in planes perpendicular to the z-direction to provide sufficiently accurate guidance to limit movement in other directions than the z-direction. To this end, the flat leaf springs preferably each have a stiffness against bending in a plane perpendicular to the z-axis which is at least three times, and, more preferably, at least five or at least seven times a stiffness of the leaf springs against bending in a plane parallel to the z-axis.
The axis of rotation of the main drive shaft 12 passes between the suspension arms 24, 25 and 26, 27 of each of the pairs of suspension arms. Thus a compact construction is achieved, because the elongated suspension arms 24-27 extend on opposite sides along the sensor unit carrier 22. Moreover, the distance in x-direction between the fixed attachments at locations 31, 33, 35 to the (posts 28, 29 of) the main body 2 and the average center of effort of shaving pressure, which is along the axis of rotation of the main drive shaft 12, is much shorter than the lengths of the suspension arms 24-27 that are also oriented mainly in x-direction. Thus, while sufficiently long suspension arms 24-27 can be accommodated for providing an amount of spring travel required for urging the sensor unit carrier 22 from the pushed-in position 22′ towards the rest position while exerting a fairly constant force, the distance in x-direction between the fixed attachments at locations 31, 33, 35 to the main body 2 and the average center of effort of shaving pressure can be much shorter than the length of the suspension arms 24-27, so that tilting about the y-axis as a result of bending moments exerted onto the suspension arms 24-27 is further reduced.
In the present example, a particularly simple construction with a relatively small number of parts is moreover achieved, because the suspension arms 24-27 are implemented as leaf springs forming the anti-tilting guides and also constitute a resilient member that urges the sensor unit carrier 22 from the pushed-in position 22′ towards the rest position of the sensor unit carrier 22. Also in other embodiments of the invention, it is advantageous for simplicity of construction and reducing the number of parts if a spring member that forms the anti-tilting guide also forms a resilient member that urges the sensor unit carrier 22 from the pushed-in position 22′ towards the rest position.
For reliable operation of the shaver 1, in particular if the shaver 1 is also arranged for wet-shaving, it is advantageous if, as in the present example, the first sensor unit 16 is mounted in a position shielded from the environment by a shielding 39, so as to be hermetically and dust free separated from the environment. The second sensor unit 17 is mounted in a position outside that shielding 39. This allows the moving sensor unit carrier 22 to be arranged completely outside the shielding 39 and no moving parts for transferring movement in z-direction to measure such movement have to extend through the shielding 39, so that the need of sealing such moving parts against the shielding is avoided.
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Although in the shown examples, the resilient member is a spring, other forms of resilient members are conceivable as well, such as a pair of mutually repelling magnets or a pneumatic cylinder.
While the invention has been described and illustrated in detail in the foregoing description and in the drawing figures, such description and illustration are to be considered exemplary and/or illustrative and not restrictive; the invention is not limited to the disclosed embodiments.
Several features have been described as part of the same or separate embodiments. However, it will be appreciated that the scope of the invention also includes embodiments having combinations of all or some of these features other than the specific combinations of features embodied in the examples.
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. 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. A single processor or other unit may fulfill the functions of several items recited in the claims. For the purpose of clarity and a concise description, features are disclosed herein as part of the same or separate embodiments; however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features disclosed. 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. Any reference signs in the claims should not be construed as limiting the scope.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19170323.0 | Apr 2019 | EP | regional |
This application is a continuation of U.S. patent application Ser. No. 17/284,897 filed Apr. 13, 2021, which is the U.S. National Phase application under 35 U.S.C. § 371 of International Patent Application No. PCT/EP2020/060302 filed Apr. 10, 2020, which claims the benefit of European Patent Application Number 19170323.0 filed Apr. 18, 2019. These applications are hereby incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17284897 | Apr 2021 | US |
| Child | 17687766 | US |
