Adjusting the exposure distance of the hair-cutting unit of a rotary electric shaver

Abstract

In a hair-cutting unit 4 for a rotary electric shaver of the type having an external cutting member 10, an internal cutting member and a support member 30, the exposed distance de of the skin contact surface 12 of the shaving track of the external cutting member 10 protruding relative to the upper surface 31 of the support member 30 is adjustable. For this purpose, a conversion mechanism 40 is provided having a first plurality of spaced apart ramp elements 41 and a second plurality of spaced apart flexible elements 42 for interacting with the ramp elements 41. Depending on the rotational direction of the relative rotation of the external cutting member 10 and the support member 30 around the central axis 14 of the hair-cutting unit 4, the flexible elements 42 are adapted to bend upwards or downwards in the axial direction A.

Description

[Technical field]

[0001] The present invention relates to a hair-cutting unit for a rotary electric shaver, which comprises: an external cutting member having a shaving track with a hair entry opening; an internal cutting member covered by the external cutting member and rotatable relative to the external cutting member about a central axis of the hair-cutting unit; A support member that surrounds and supports the external cutting member; and an adjustment system for adjusting the exposed distance that the skin contact surface of the shaving track protrudes relative to the upper surface of the support member, the adjustment system including a drive system for realizing relative rotation of the external cutting member and the support member around a central axis, and a conversion mechanism for converting the relative rotation of the external cutting member and the support member around the central axis into relative movement of the external cutting member and the support member in an axial direction parallel to the central axis.

[0002] Furthermore, the present invention relates to a shaving assembly comprising at least one hair-cutting unit as described above and a base unit supporting the at least one hair-cutting unit, and also to a rotary electric shaver comprising a main body and such a shaving assembly, the base unit of the shaving assembly being connected to the main body. [Background technology]

[0003] Rotary electric shavers and shaving assemblies for rotary electric shavers are well known. Electric shavers are typically used to shave body hair, which may be facial hair, and are powered from a mains power source and / or an electrical energy storage device, such as a battery.

[0004] In a commonly known setup, the shaving assembly comprises an assembly of a base unit and at least one hair-cutting unit supported by the base unit. Conventionally, the hair-cutting unit comprises a combination of an external cutting member with a shaving track with a hair entry opening as a non-driven element and an internal cutting member as a driven element, where at least the internal cutting member has one or more cutting edges. In such a case, the use of the shaving assembly integrated in a rotary electric shaver includes placing the shaving assembly in an operating mode in which the internal cutting member of the hair-cutting unit is actually moved, and moving the shaving assembly over the skin so that the shaving track of the external cutting member of the hair-cutting unit faces and contacts the skin. In this process, the hair protruding from the skin is captured in the internal space of the hair-cutting unit, where the hair abuts against the external cutting member at the position of the hair entry opening and is cut when it encounters the cutting edge of the rotating internal cutting member. Summary of the Invention [Problem to be solved by the invention]

[0005] An ongoing challenge in the field of rotary electric shavers is the search for practical ways to combine high comfort with high shaving performance, especially high shaving closeness. For example, the option of rotating the external cutting member relative to a surrounding fixed support member is considered. This can improve the hair-catching ability of the hair-cutting unit, since the skin is allowed to encounter more open areas of the external cutting member, i.e. more hair entry openings. An improvement in comfort can also be obtained, since the skin does not have time / opportunity to dome into the shaving trajectory, and the friction vector where the shaving trajectory contacts the skin moves around continuously, resulting in low friction.

[0006] Advantageously, the hair-cutting unit is designed such that the user is provided with the possibility to adjust the exposure distance, where the skin-contact surface of the shaving track protrudes relative to the upper surface of the support member, based on personal requirements. Generally speaking, a large exposure distance provides a high shaving closeness at the expense of comfort, whereas a small exposure distance provides a high comfort at the expense of shaving closeness. The object of the present invention is to provide a type of hair-cutting unit having an adjustment system for adjusting the exposure distance, which is effective, reliable and robust, while not taking up a large amount of space in the hair-cutting unit and not increasing the complexity of the process of disassembling and assembling the hair-cutting unit, such as for cleaning purposes. The hair-cutting unit according to the present invention may be configured to realize the above-mentioned option of rotating the external cutting member during operation, but this is not essential. [Means for solving the problem]

[0007] The present invention provides a hair-cutting unit for a rotary electric shaver, comprising: an external cutting member having a shaving track with a hair entry opening; an internal cutting member covered by the external cutting member and rotatable relative to the external cutting member about a central axis of the hair-cutting unit; A support member that surrounds and supports the external cutting member; and an adjustment system for adjusting an exposed distance of the skin contact surface of the shaving track protruding from the upper surface of the support member, the adjustment system including a drive system for realizing relative rotation of the external cutting member and the support member around a central axis, and a conversion mechanism for converting the relative rotation of the external cutting member and the support member around the central axis into relative movement of the external cutting member and the support member in an axial direction parallel to the central axis, Here, the conversion mechanism is a first plurality N1 of lamp elements disposed on one of an inner surface of the support member surrounding the outer cutting member and a circumferential outer surface of the outer cutting member and spaced apart from one another; Each of the lamp elements is inclined with respect to an imaginary plane perpendicular to the central axis, and each lamp element has an axial extension in the axial direction; and a second plurality N2 of flexible elements configured to interact with the ramp element and spaced apart from one another on the other of the inner surface of the support member and the outer surface of the external cutting member, each of the flexible elements being axially flexible and arranged relative to the ramp element such that when the relative rotation of the external cutting member and the support member around the central axis is in a first rotational direction, the flexible element contacts the ramp element on an upper side of the ramp element facing the shaving path and bends upward while sliding over the ramp element, and when the relative rotation of the external cutting member and the support member around the central axis is in a second rotational direction opposite to the first rotational direction, the flexible element contacts the ramp element on a lower side of the ramp element facing away from the shaving path and bends downward while sliding over the ramp element.

[0008] From the above definition of the hair-cutting unit according to the invention, it is derived that the adjustment system included in the hair-cutting unit and for adjusting the exposure distance comprises a conversion mechanism for converting the relative rotation of the external cutting member and the support member around the central axis into a relative movement of the external cutting member and the support member in the axial direction, the conversion mechanism comprising a combination of a first plurality N1 of spaced apart ramp elements and a second plurality N2 of spaced apart flexible elements, one type of the elements being arranged on the inner surface of the support member surrounding the external cutting member and another type of the elements being arranged on the circumferential outer surface of the external cutting member. Each ramp element is inclined with respect to an imaginary plane perpendicular to the central axis, each ramp element having an axial extension in the axial direction. The flexible elements function for interaction with the ramp elements, each of the flexible elements being flexible in the axial direction. The configuration of the conversion mechanism is such that the rotation direction of the relative rotation of the external cutting member and the support member around the central axis determines whether the flexible element contacts the lamp element on the upper side of the lamp element facing the shaving path and is deflected upwards while sliding on the upper side of the lamp element, or whether the flexible element contacts the lamp element on the lower side of the lamp element facing away from the shaving path and is deflected downwards while sliding on the lower side of the lamp element. Thus, it is realized that in the first case, the relative axial position of the external cutting member and the support member is obtained, in which case one of the external cutting member and the support member on which the flexible element is present is axially raised relative to the other of the external cutting member and the support member, and in the second case, the relative axial position of the external cutting member and the support member is obtained, in which case one of the external cutting member and the support member on which the flexible element is present is axially lowered relative to the other of the external cutting member and the support member. It is thus achieved that, based on the tilt direction of the lamp element and the ability of the flexible element to flex up and down, changing the rotational direction of the relative rotation of the external cutting member and the support member about the central axis results in changing the exposure distance.For completeness, it should be noted that the terms "up," "raised," "lowered," "above" and "below" used in this document are understood with reference to the assumption that the position of the shaving orbit relative to the position of the internal cutting member is at a higher axial position.

[0009] The ramp element and the flexible element may be of any suitable design. The ramp element can be provided as a rib on the annular carrier or directly on the respective surface, and the flexible element can be provided as an end tab of a flexible lever arranged on the annular carrier or directly on the respective surface. The advantage of the design of the conversion mechanism of the adjustment system with the ramp element and the flexible element is related to the situation when the user disassembles the hair-cutting unit for the purpose of cleaning or replacing the elements and then reassembles the hair-cutting unit. The fact is that without the relative rotation of the external cutting member and the support member around the central axis in a respective rotational direction, the setting with the maximum exposure distance cannot be obtained. As a result, there is no risk of accidentally obtaining this setting with the lowest level of comfort and the highest level of risk of skin damage.

[0010] Advantageously, the lamp elements and the flexible elements are regularly distributed around the central axis. The dimension of the flexible elements in the tangential direction around the central axis does not necessarily have to be larger than the dimension of the space between adjacent lamp elements in said tangential direction, in order to avoid a situation in which all flexible elements are located between the lamp elements in said tangential direction. The fact is that the hair-cutting unit according to the invention can be designed with different values ​​for the first plurality N1 and the second plurality N2. In particular, it is possible to select the first plurality N1 to be larger than the second plurality N2. This is preferably done in such a way that in any relative rotational position of the external cutting member and the support member around the central axis, at least three of the flexible elements contact at least three upper side surfaces of the ramp element when the relative rotation of the external cutting member and the support member is in the first rotational direction, and at least three of the flexible elements contact at least three lower side surfaces of the ramp element when the relative rotation of the external cutting member and the support member is in the second rotational direction. This results in a high stability of the hair-cutting unit under all circumstances. The values ​​of the first plurality N1 and the second plurality N2 can be 15 and 12, respectively, to give a practical example.

[0011] In a practical embodiment of the hair-cutting unit according to the invention, the conversion mechanism of the adjustment system further comprises a first abutment member and a second abutment member for limiting the relative axial movement of the external cutting member and the support member, the first abutment member and the second abutment member defining respectively a maximum and a minimum exposure distance; The axial extension of the lamp element is greater than the difference between the maximum and minimum exposed distances.

[0012] The individual abutment members can be provided in any suitable manner, for example with planes facing each other at a distance. It will be practical if at least one of the abutment members is included in the support member. In any case, providing the hair-cutting unit with individual abutment members is a practical way of defining the maximum and minimum values ​​of the exposed distance. By selecting the axial extension of the lamp element to be greater than the difference between the maximum and minimum values ​​of the exposed distance, it is achieved that the flexible element is allowed to contact the upper or lower side of the lamp element with a constant contact force at the relative axial positions of the external cutting member and the support member corresponding to the maximum and minimum values ​​of the exposed distance, respectively. In this regard, it is practical if, in the axial direction, when the exposed distance has a central value between the maximum and minimum values, the position of any flexible element not in contact with the lamp element is a central position relative to the upper and lower sides of the lamp element. As a result, the said contact force between the flexible element and the lamp element is substantially equal at the maximum and minimum times of the exposed distance.

[0013] In a practical embodiment of the hair-cutting unit according to the invention, the external cutting member has a flange at a position between the first and second abutment members in the axial direction, the upper surface of the flange contacting the first abutment member resulting in a maximum value of the exposed distance, and the lower surface of the flange contacting the second abutment member resulting in a minimum value of the exposed distance. If the external cutting member is rotatable about a central axis, it is further conceivable that the drive system of the adjustment system is configured to realize the rotation of the external cutting member by engaging with the flange. For example, the drive system has a drive gear, the flange being provided with peripheral toothing for enabling the drive gear to interact with the flange and thereby to bring about a rotational movement of the external cutting member.

[0014] The present invention is suitable for application in conventional situations, where it is only intended to rotate the internal cutting member continuously around the central axis during the shaving operation, while maintaining a stationary position of both the external cutting member and the support member around the central axis. The present invention is also applicable to other situations, including situations where it is intended to rotate the external cutting member continuously around the central axis, as well as to rotate the internal cutting member continuously around the central axis during the shaving operation, while maintaining a stationary position of the support member around the central axis. In this respect, the following two options are covered by the present invention with respect to the drive system of the adjustment system. These options are i) the drive system of the adjustment system is configured to realize a relative rotation of the external cutting member and the support member over a limited angle around the central axis, and ii) the drive system of the adjustment system is configured to realize a continuous relative rotation of the external cutting member and the support member around the central axis.

[0015] i) When the drive system of the adjustment system is configured to realize relative rotation of the external cutting member and the support member over a limited angle around the central axis, varying the exposure distance can be based on the following features: Relative rotation of the outer cutting member and the support member through a limited angle about the central axis in a first rotational direction results in a change in exposed distance from a minimum to a maximum; and Relative rotation of the outer cutting member and the support member through a limited angle about the central axis in a second rotational direction results in a change in the exposed distance from a maximum to a minimum.

[0016] Advantageously, the hair-cutting units are configured such that the limited angle does not need to be greater than 90 degrees. As a result, varying the exposure distance can be performed very quickly. This means that when at least two hair-cutting units are used in a shaving assembly, no additional measures are required to achieve synchronization of the hair-cutting units as far as the setting of the exposure distance in each hair-cutting unit is concerned.

[0017] ii) When the drive system of the adjustment system is configured to realize continuous relative rotation of the outer cutting member and the support member around the central axis, varying the exposure distance can be based on the following features: Continued relative rotation of the outer cutting member and the support member about the central axis in a first rotational direction results in a maximum value of the exposed distance. Continued relative rotation of the outer cutting member and the support member about the central axis in a second rotational direction results in a minimum exposed distance. A change in the rotational direction of the continuous relative rotation of the external cutting member and the support member about the central axis from a first rotational direction to a second rotational direction causes the exposed distance to change from a maximum to a minimum; and A change in the rotational direction of the continuous relative rotation of the external cutting member and the support member about the central axis from the second rotational direction to the first rotational direction results in a change in the exposed distance from a minimum to a maximum.

[0018] For the sake of completeness, it is noted that the difference between the first and the latter case does not lie in the manner in which the desired value of the exposure distance is obtained, but rather in the fact that in the first case, the relative rotation in either direction of rotation of the external cutting member and the support member about the central axis is stopped (immediately) after the desired value of the exposure distance has been obtained, whereas in the latter case, said relative rotation is continued for reasons other than the exposure distance setting.

[0019] The above-mentioned and other aspects of the present invention will become apparent from and will be elucidated with reference to the following detailed description of an embodiment of a hair-cutting unit having an external cutting member, an internal cutting member, a support member and an adjustment system, where the adjustment system functions to adjust an exposed distance that a skin-contacting surface of a shaving track of the external cutting member protrudes relative to an upper surface of the support member, and where the adjustment system has a conversion mechanism configured to function based on an interaction between a ramp element disposed on an inner surface of the support member surrounding the external cutting member and a flexible element disposed on a circumferential outer surface of the external cutting member. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic perspective view of a rotary electric shaver according to an embodiment of the present invention, the rotary electric shaver having a shaving assembly and a body. [Diagram 2] FIG. 2 is a schematic perspective view of an external cutting member, decorative cap and internal cutting member of a hair-cutting unit of a shaving assembly, with both the external cutting member and the cap shown partially cut away; [Diagram 3] FIG. 2 shows a schematic perspective view of a support member of the hair-cutting unit and a lamp element arranged thereon. [Figure 4] FIG. 2 diagrammatically shows a perspective view of an external cutting member and a flexible element disposed thereon. [Diagram 5] FIG. 2 is a diagram showing a perspective view of an integrated flexible element and a carrier for the flexible element; [Figure 6] FIG. 2 diagrammatically shows a bottom view of an integrated element including a flexible element and a carrier for the flexible element. [Figure 7] FIG. 2 diagrammatically shows a bottom view of an assembly of a support member with a lamp element and an external cutting member with a flexible element. [Figure 8] FIG. 13 illustrates how the flexible element interacts with the lamp element. [Figure 9] FIG. 2 shows diagrammatically a cross-sectional representation of the external cutting member, the support member and the hair chamber associated with the hair-cutting unit. [Figure 10] FIG. 10 is a diagram showing a detail of FIG. [Figure 11] FIG. 2 diagrammatically shows a top view of an external cutting member comprising a flexible element and further comprising a flange with peripheral teeth. [Figure 12] FIG. 2 illustrates how the individual external cutting members of the three hair-cutting units of the shaving assembly are driven by a drive gear located in a central position between the hair-cutting units. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The invention will now be explained in more detail with reference to the figures, in which equivalent or similar parts are designated with the same reference numbers.

[0022] FIG. 1 shows a rotary electric shaver suitable for use in shaving as a practical example of a rotary electric shaver 1 according to an embodiment of the present invention. The rotary electric shaver 1 has a main body 2 and a shaving assembly 3, where the main body 2 is designed to enable a user of the shaver 1 to hold and handle the shaver 1, and the shaving assembly 3 is the part of the shaver 1 that is placed on the skin and moved over the skin for hair removal. In this embodiment, the shaving assembly 3 has three hair-cutting units 4 supported on a base unit 5 of the shaving assembly 3. When the rotary electric shaver 1 is actually applied to perform a shaving operation, the actual cutting process of the hair protruding from the skin is performed at the position of the hair-cutting units 4. In the context of the present invention, the number of hair-cutting units 4 can be freely selected and does not necessarily have to be three, but is at least one. The main body 2 can have the function of housing at least one electric motor for driving the elements of the individual hair-cutting units 4. The main body 2 can further include a means, such as a rechargeable battery, for supplying power to the at least one electric motor. It is practical if the shaving assembly 3 and the main body 2 are releasably connectable to one another, as known per se in the field of rotary electric shavers.

[0023] Each hair-cutting unit 4 comprises a combination of an external cutting member 10 and an internal cutting member 20, as will be explained in more detail below with reference to FIG. 2. The external cutting member 10 is of a generally cup-shaped design, suitable for at least partially accommodating the internal cutting member 20 therein. The external cutting member 10 has an annular shaving track 11, the upper surface of which is a skin contact surface 12 intended to face and contact the skin to be shaved. The shaving track 11 comprises lamellae 13 extending along the width of the shaving track 11 in a substantially radial direction relative to a central axis 14 of the hair-cutting unit 4, which axis coincides with an axis of rotation 21, around which the internal cutting member 20 is rotatable relative to the external cutting member 10. The openings present between the lamellae 13 constitute hair entry openings 15 of the shaving track 11. The lateral sides of the lamellae 13 constitute hair-cutting surfaces 16 suitable for cutting hair in cooperation with hair-cutting edges 22 of the hair-cutting elements 23 of the internal cutting member 20. The invention also relates to cases where the shaving path 11 does not have lamellae 13 or does not only have lamellae 13, for example where the entire shaving path 11 is provided with tooth-like elements and / or a (circular) hole pattern instead of or in addition to the lamellae 13. The invention also relates to cases where there are multiple shaving paths 11 on the external cutting member 10.

[0024] The shaving action can be performed when the internal cutting member 20 is actuated to rotate and a portion of the skin is actually contacted by the external cutting member 10 at the location of the skin contact surface 12. The actuation of the internal cutting member 20 can be performed in a known manner by the drive mechanism of the rotary electric shaver 1. When the combination of the external cutting member 10 and the internal cutting member 20 is moved over a portion of the skin while the internal cutting member 20 is driven to rotate, it is realized that, as a result of the cooperation between the hair-cutting surface 16 of the shaving track 11 of the external cutting member 10 and the hair-cutting edge 22 of the hair-cutting element 23 of the rotating internal cutting member 20, hairs protruding from the portion of the skin are captured in the hair entry opening 15 of the hair-cutting track 12 of the external cutting member 10 and cut at that location.

[0025] Besides the shaving track 11, the external cutting member 10 has a central part 17 including a central bearing designed to be used for rotatably supporting the internal cutting member 20 in the hair-cutting unit 4. The central part 17 of the external cutting member 10 also serves to support a decorative cap 25 arranged to cover a part of the outer surface of the external cutting member 10. In the illustrated example, the central part 17 has a centrally located recess and the cap 25 has a protrusion which is received in the recess.

[0026] Each hair-cutting unit 4 further comprises a support member 30. The support member 30 has an upper surface 31 surrounding the external cutting member 10. According to the invention, each hair-cutting unit 4 comprises an adjustment system for adjusting an exposure distance de, by which the skin contact surface 12 of the shaving track 11 projects relative to the upper surface 31 of the support member 30, as will be described below with reference to Figs. 3 to 12. It should be noted that the presence of the adjustment system in the hair-cutting unit 4 allows the user to set the exposure distance de according to personal preferences, which may be different for different skin areas subjected to a shaving action. Generally speaking, the adjustment system is configured to i) realize a relative rotation of the external cutting member 10 and the support member 30 around the central axis 14, and ii) convert the relative rotation of the external cutting member 10 and the support member 30 around the central axis 14 into a relative movement of the external cutting member 10 and the support member 30 in an axial direction A parallel to the central axis 14. In this embodiment, the external cutting member 10 is rotatable at least over a limited angle and is also displaceable to a limited extent in the axial direction A, while the support member 30 is a fixed element of the hair-cutting unit 4. Thus, in this embodiment, the realization of the relative rotation of the external cutting member 10 and the support member 30 around the central axis 14 is achieved by realizing the rotation of the external cutting member 10 around the central axis 14, and the realization of the relative movement of the external cutting member 10 and the support member 30 in the axial direction A is achieved by realizing the movement of the external cutting member 10 in the axial direction A.

[0027] To convert the rotation of the external cutting member 10 around the central axis 14 into a movement of the external cutting member 10 in the axial direction A, the adjustment system comprises a conversion mechanism 40, of which elements 41, 42 are shown in Figs. 3 to 10. The fact is that the conversion mechanism 40 comprises ramp elements 41 spaced apart from one another and flexible elements 42 spaced apart from one another to interact with the ramp elements 41. In this embodiment, the ramp elements 41 are arranged on the inner surface 32 of the support member 30 surrounding the external cutting member 10, while the flexible elements 42 are arranged on the circumferential outer surface 18 of the external cutting member 10. Each ramp element 41 is oriented so as to be inclined with respect to an imaginary plane perpendicular to the central axis 14, where each ramp element has an axial extension in the axial direction A.

[0028] The ramp elements 41 are provided as ribs on the inner surface 32 of the support member 30, while the flexible elements 42 are provided as end tabs of a flexible lever 43 arranged on an annular carrier 44 arranged on the external cutting member 10. The lever 43 and the carrier 44 are integrated into a single element, which may be made of metal, for example as shown in Figures 5 and 6. Furthermore, as can be seen in Figure 7, in this embodiment the ramp elements 41 and the flexible elements 42 are regularly distributed around the central axis 14, where the ramp elements 41 are made up of a first plurality N1 of 15 pieces, while the flexible elements 42 are made up of a second plurality N2 of 12 pieces. The individual designs of the peripheral rows of spaced apart lamp elements 41 and the peripheral rows of spaced apart flexible elements 42 are selected to ensure that at least three of the flexible elements 42 are in contact with at least three of the lamp elements 41 in any relative rotational position of the external cutting member 10 and the support member 30 about the central axis 14.

[0029] As mentioned before, the flexible element 42 is for interacting with the ramp element 41. In fact, the positioning of the ramp element 41 and the positioning of the flexible element 42 in the support member 30 are adapted to one another such that the ramp element 41 and the flexible element 42 are in an axially overlapping position in the hair-cutting unit 4. The flexible element 42 is comparable to a leaf spring. In particular, the flexible element 42 is flexible in the axial direction A. With reference to Fig. 8, it should be noted that this means that when the external cutting member 10 is rotated in a counterclockwise rotational direction around the central axis 14, the flexible element 42 contacts the ramp element 41 at its upper side 41a facing the shaving path 11 and is pushed upwards by the ramp element 41, resulting in a lifting force on the external cutting member 10, whereas when the external cutting member 10 is rotated in a clockwise rotational direction around the central axis 14, the flexible element 42 contacts the ramp element 41 at its lower side 41b facing away from the shaving path 11 and is pushed downwards by the ramp element 41, resulting in a lowering force on the external cutting member 10. It is this feature of the conversion mechanism 40 that is effective to vary the exposure distance de. As seen at the level of a single flexible element 42, when the external cutting member 10 is rotated about the central axis 14, the flexible element 42 is caused to slide successively along successive ramp elements 41, either at the upper side 41a or at the lower side 41b of the ramp elements 41 depending on the rotational direction of the rotational movement of the external cutting member 10, and to assume a neutral, undeflected state in the spaces between the ramp elements 41, because the dimensions of the flexible element 42 are small enough that the entire flexible element 42 fits into said spaces.

[0030] 9 and 10, it should be noted that the conversion mechanism 40 further comprises a first abutment member 45 and a second abutment member 46 for the purpose of defining the maximum and minimum values ​​of the exposed distance de, respectively. In this embodiment, the first abutment member 45 comprises an annular surface area of ​​the support member 30 and the second abutment member 46 comprises an upper surface of the annular wall 36 defining a hair chamber 35 associated with the hair-cutting unit 4. Furthermore, the external cutting member 10 comprises a flange 47 at a position between the first abutment member 45 and the second abutment member 46 in the axial direction A. When the external cutting member 10 is rotated in a counterclockwise direction about the central axis 14, the resulting lifting force on the external cutting member 10 causes the upper surface 47a of the flange 47 to abut against the first abutment member 45, thereby obtaining a maximum value of the exposed distance de, whereas when the external cutting member 10 is rotated in a clockwise direction about the central axis 14, the resulting lowering force on the external cutting member 10 causes the lower surface 47b of the flange 47 to abut against the second abutment member 46. Thus, the maximum value of the exposed distance de is determined by the first abutment member 45, whereas the minimum value of the exposed distance de is determined by the second abutment member 46. Changing the exposed distance de from one value to the other is performed by rotating the external cutting member 10 about the central axis 14 in the appropriate rotational direction over an angular distance sufficient for the flange 47 to reach a new axial abutment position against the appropriate one of the first abutment member 45 and the second abutment member 46. The axial extension of the lamp element 41 is greater than the difference between the maximum and minimum values ​​of the exposed distance de, thereby ensuring that the lamp element 41 contacts the flexible element 42 at any possible setting of the exposed distance de.

[0031] To realize the rotation of the external cutting member 10 around the central axis 14, the adjustment system comprises a drive system 50. In this embodiment, the flange 47 is provided with peripheral teeth 48, as can be seen in Figs. 11 and 12. As a result, the external cutting member 10 can be driven by a gear engaging the teeth 48. With reference to Fig. 12, it is noted that it is advantageous if one central gear 51 is used to simultaneously drive the individual external cutting members 10 of the hair-cutting unit 4. After the user indicates the desire to change the value of the exposure distance de, for example by pressing an appropriate button, by touching a touch screen that may be present on the main body 2 or on a cradle for holding the rotary electric shaver 1, or by using an app on a mobile device configured to control the operation of the shaver 1, the central gear 51 is rotated, where the direction of rotation of the rotational movement is set so that the desired new value of the exposure distance de can be obtained. This setting of the direction of rotation of the rotational movement of the central gear 51 can be done in any suitable manner and using any suitable control mechanism. For example, the central gear 51 can be driven by an electric motor provided solely for that purpose, which is controlled to reverse the direction of rotation of its output shaft when a change in the value of the exposure distance de is realized, or a coupling device is provided between the output shaft of the electric motor and the central gear 51, which device is adjustable to reverse the manner in which the rotation of the output shaft of the electric motor is transmitted to the central gear 51. Having a dedicated electric motor offers the possibility to operate the adjustment system independently of the internal cutting member 20 and to change the value of the exposure distance de during the shaving operation, if desired. The exposure setting de can thus be an adaptive shaving function.

[0032] In the hair-cutting unit 4 of this embodiment, one possibility is to operate the drive system 50 only when a change in the value of the exposure distance de is desired, and to terminate the rotation of the central gear 51 as soon as or immediately after the new value is reached. In the illustrated configuration, changing the value of the exposure distance de requires only a quarter turn of the central gear 51 and each external cutting member 10 engaged by it. Another possibility is to operate the drive system 50 continuously, such that the individual external cutting members 10 are rotated continuously about their individual central axes 14. This can be done, for example, as a measure aimed at improving the shaving comfort. Then, when it is desired to change the value of the exposure distance de, this is done by realizing a rotation of the central gear 51 in the appropriate direction, which rotation continues as long as the rotation of the individual external cutting members 10 is desired. In any case, the newly set value of the exposure distance de is maintained, as long as the external cutting members 10 are not rotated about the central axis 14 in a rotation direction related to another value of the exposure distance de.

[0033] The scope of the present invention is not limited to the above examples, and it will be apparent to those skilled in the art that some modifications and changes can be made thereto without departing from the scope of the present invention defined in the appended claims. It is intended that the present invention be construed as including all such modifications and changes insofar as they are within the scope of the claims or their equivalents. Although the present invention has been illustrated and described in detail in the drawings and description, such illustrations and descriptions are merely explanatory or exemplary and not restrictive. The present invention is not limited to the disclosed embodiments. The drawings are schematic, in which details that are not necessary for understanding the present invention may be omitted and are not necessarily drawn to scale.

[0034] 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 figures, the description, and the appended claims. In the claims, the word "comprising" does not exclude other steps or elements, and the indefinite article "a" or "an" does not exclude a plurality. Any reference signs in the claims should not be construed as limiting the scope of the invention.

[0035] Elements and aspects discussed for or in connection with a particular embodiment can be combined with elements and aspects of other embodiments as appropriate, unless otherwise expressly stated. Thus, 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.

[0036] The terms "having" and "including" as used herein will be understood by those skilled in the art to cover the term "consisting of." Thus, the terms "having" or "including" may mean "consisting of" in one embodiment, but may mean "including / having / comprising at least the specified species and, optionally, one or more other species" in another embodiment.

[0037] In the above, reference has been made to a hair chamber 35 associated with the hair-cutting unit 4. In the context of the present invention, it may be practical if the shaving assembly 3 has individual hair chambers, i.e. one hair chamber per hair-cutting unit 4, but this does not alter the fact that the present invention is also applicable in situations where one hair chamber is shared between two or more hair-cutting units 4.

[0038] Notable aspects of the invention can be summarized as follows: In a hair-cutting unit 4 for a rotary electric shaver 1 of the type having an external cutting member 10, an internal cutting member 20 and a support member 30, an exposure distance de, by which the skin contact surface 12 of the shaving track 11 of the external cutting member 10 projects relative to the upper surface 31 of the support member 30, is adjustable. For this purpose, an adjustment system is provided, which comprises a drive system 50 and a conversion mechanism 40 having a first plurality of ramp elements 41 spaced apart from one another and a second plurality of flexible elements 42 spaced apart from one another to interact with the ramp elements 41. Depending on the rotational direction of the relative rotation of the external cutting member 10 and the support member 30 around the central axis 14 of the hair-cutting unit 4, the flexible elements 42 are made to bend upwards or downwards in the axial direction A, which is useful for moving the external cutting member 10 and the support member 30 relative to one another in the axial direction A or for maintaining the relative axial position of the external cutting member 10 and the support member 30 related to either a maximum or a minimum value of the exposure distance de. Separate abutment members 45, 46 at appropriate positions on the hair-cutting unit 4 can be used to define the maximum and minimum exposure distance de.

Claims

1. A hair-cutting unit for a rotary electric shaver, comprising: an external cutting member having a shaving track with a hair entry opening; an internal cutting member surrounded by the external cutting member and rotatable relative to the external cutting member about a central axis of the hair-cutting unit; a support member surrounding and supporting the external cutting member; an adjustment system for adjusting an exposed distance of a skin contact surface of the shaving track protruding from an upper surface of the support member, the adjustment system including a drive system for realizing relative rotation of the external cutting member and the support member about the central axis, and a conversion mechanism for converting the relative rotation of the external cutting member and the support member about the central axis into relative movement of the external cutting member and the support member in an axial direction parallel to the central axis; The conversion mechanism is a first plurality of ramp elements disposed in spaced relation to one another on one of an inner surface of the support member surrounding the outer cutting member and a circumferential outer surface of the outer cutting member, A first plurality of lamp elements, each of which is inclined with respect to an imaginary plane perpendicular to the central axis and has an axial extension portion extending in the axial direction; a second plurality of flexible elements arranged at intervals from one another on the other of the inner surface of the support member and the outer surface of the external cutting member to interact with the ramp element, each of the flexible elements being flexible in the axial direction, and the flexible elements being arranged relative to the ramp element such that when the relative rotation of the external cutting member and the support member around the central axis is in a first rotational direction, the flexible elements contact the ramp element at an upper side of the ramp element facing the shaving path and are adapted to bend upward while sliding over the ramp element, and when the relative rotation of the external cutting member and the support member around the central axis is in a second rotational direction opposite to the first rotational direction, the flexible elements contact the ramp element at a lower side of the ramp element facing away from the shaving path and are adapted to bend downward while sliding over the ramp element.

2. The conversion mechanism of the adjustment system is a first abutment member and a second abutment member that limit relative movement of the external cutting member and the support member in the axial direction, the first abutment member and the second abutment member defining a maximum and a minimum value of the exposed distance, respectively; The hair-cutting unit according to claim 1 , wherein the axial extension of the lamp element is greater than the difference between the maximum and minimum values ​​of the exposure distance.

3. 3. The hair-cutting unit according to claim 2, wherein the position of any flexible element not in contact with the lamp element in the axial direction is a central position relative to the upper and lower sides of the lamp element when the exposed distance has a central value between a maximum value and a minimum value.

4. the external cutting member has a flange at a location between the first abutment member and the second abutment member in the axial direction; an upper surface of the flange contacting the first abutment member provides a maximum value of the exposed distance; A hair-cutting unit according to claim 2 or 3, wherein an underside of the flange contacting the second abutment member provides a minimum value of the exposed distance.

5. The hair-cutting unit according to claim 4, wherein the external cutting member is rotatable about the central axis, and a drive system of the adjustment system provides rotation of the external cutting member by engagement with the flange.

6. A hair-cutting unit according to any of claims 2 to 5, wherein at least one of the abutment members is included in the support member.

7. a drive system of the adjustment system providing relative rotation of the external cutting member and the support member through a limited angle about the central axis; relative rotation of the external cutting member and the support member about the central axis in the first rotational direction through the limited angle results in a change in the exposed distance from a minimum to a maximum; 7. A hair-cutting unit as claimed in any one of claims 2 to 6, wherein relative rotation of the external cutting member and the support member about the central axis in the second rotational direction through the limited angle results in a change in the exposed distance from a maximum to a minimum.

8. The hair-cutting unit according to claim 7, wherein the limited angle is less than 90 degrees.

9. a drive system of the adjustment system providing continuous relative rotation of the outer cutting member and the support member about the central axis; continued relative rotation of the external cutting member and the support member about a central axis in the first rotational direction results in a maximum value of the exposed distance; continued relative rotation of the external cutting member and the support member about the central axis in the second rotational direction results in a minimum of the exposed distance; a change in a rotational direction of the continuous relative rotation of the external cutting member and the support member about the central axis from the first rotational direction to the second rotational direction results in a change in the exposed distance from a maximum to a minimum; 7. A hair-cutting unit as claimed in any one of claims 2 to 6, wherein a change in the direction of rotation of the continuous relative rotation of the external cutting member and the support member about the central axis from the second direction of rotation to the first direction of rotation results in a change in the exposure distance from a minimum to a maximum.

10. A hair-cutting unit according to any of the preceding claims, wherein the flexible element is provided as an end tab of a flexible lever arranged on an annular carrier.

11. A hair-cutting unit according to any of the preceding claims, wherein the lamp elements and the flexible elements are regularly distributed around the central axis.

12. a dimension of the flexible element in a tangential direction about the central axis is smaller than a dimension of a space between adjacent lamp elements in the tangential direction; 12. A hair-cutting unit according to any one of claims 1 to 11, wherein the first plurality is greater than the second plurality, and at any relative rotational position of the external cutting member and the support member about the central axis, when the relative rotation of the external cutting member and the support member is in the first rotational direction, at least three of the flexible elements contact at least three upper sides of the lamp elements, and when the relative rotation of the external cutting member and the support member is in the second rotational direction, at least three of the flexible elements contact at least three lower sides of the lamp elements.

13. A hair-cutting unit according to any preceding claim, wherein the first plurality is fifteen and the second plurality is twelve.

14. A shaving assembly comprising at least one hair-cutting unit according to any one of claims 1 to 13 and a base unit supporting said at least one hair-cutting unit.

15. 15. A rotary electric shaver having a body and a shaving assembly according to claim 14, wherein the base unit of the shaving assembly is connected to the body.

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