Patent Publication Number: US-9409301-B2

Title: Cap with multi-angle annular corrugation surfaces for shaving apparatus

Description:
FIELD OF THE INVENTION 
     The present invention relates to a cap which is intended to be applied in a shaving head of a shaving apparatus, and which has a surface for contacting skin to be shaved, wherein the skin contacting surface comprises at least two annular corrugations, wherein each annular corrugation has an annular central surface, an inner annular boundary surface and an outer annular boundary surface. The present invention also relates to a shaving head having such a cap and a cutting member which is adapted to cutting through hair; a unit which is intended to be applied in a shaving apparatus, comprising a portion of a housing of the shaving apparatus, and at least one such a shaving head; and a shaving apparatus, comprising at least one such a shaving head. 
     It is generally known that a shaving apparatus is applicable for the purpose of shaving off hair. A well-known type of shaving apparatus is an electric shaving apparatus, i.e. a shaving apparatus comprising an electric motor for driving one or more components of the shaving apparatus. 
     The electric shaving apparatus comprises at least one shaving head, which is a composite element of the shaving apparatus, and which serves for actually catching hairs and performing a hair cutting action. To this end, among other things, the shaving head comprises a cap which has a surface for contacting skin to be shaved, wherein the cap is provided with apertures for catching hairs and letting through hairs to an interior space of the shaving head. In this interior space, close to the cap, a cutting member is arranged, which is driven such as to move with respect to the cap during operation of the shaving apparatus, so that hairs extending through the apertures of the cap are cut off. It is clear that the cap also has a function in protection the skin, as the cutting member is shielded off from the skin by the cap. 
     For the purpose of shaving a certain area of skin, the cutting member is driven, the shaving head is put in contact with the skin, and the shaving apparatus is moved along the skin while the contact between the shaving head and the skin is maintained, so that a continuous process of catching hairs and cutting off hairs is performed. 
     Among other things, the shape of the cap of the at least one shaving head of the shaving apparatus is an important factor for determining a sensation which is experienced by a person whose skin is subjected to a shaving operation. An example of another important factor in this respect is the extent to which the shaving head is movable with respect to a portion of the shaving apparatus which is held by a user during a shaving operation. 
     A wide variety of caps is known and applied in practice. Usually, a shaving head of a so-called rotary shaving apparatus, i.e. a shaving apparatus in which the cutting member of the at least one shaving head is rotatably arranged, is provided with a cap having a circular circumference. In a particular type of cap, a skin contacting surface of the cap comprises three concentrically arranged annular corrugations, wherein the apertures for catching hairs are located in these annular corrugations. 
     It is an objective of the present invention to provide a cap which is intended to be applied in a shaving head of a shaving apparatus, and which is shaped in such a way that it is capable of realizing an increased feeling of comfort for a user of a shaving apparatus comprising at least one shaving head having this cap. This objective is achieved by a cap having a skin contacting surface which comprises at least two annular corrugations, wherein each annular corrugation has an annular central surface, an inner annular boundary surface and an outer annular boundary surface, and wherein, in a direction from a center of the cap to an outer periphery of the cap, a course of the central surface of an outmost annular corrugation significantly deviates from an expected course of an imaginary smooth flowing plane following the at least one central surface of the at least one other annular corrugation, wherein the central surface of the outmost annular corrugation slants away from the imaginary smooth flowing plane following the at least one central surface of the at least one other annular corrugation. 
     According to the present invention, the central surface of the outmost annular corrugation of the cap is not on an imaginary smooth flowing plane with the central surface(s) of the other annular corrugation(s). In this way, it is possible to obtain a clearly drooping configuration of the central surface of the outmost annular corrugation with respect to the central surface(s) of the other annular corrugation(s). Application of the cap according to the present invention appears to enhance the feeling of comfort of the user, indeed. An explanation is found in the fact that a barrier which is constituted by the outer annular boundary surface of the outmost annular corrugation is lower in the cap according to the present invention than in any of the known caps having at least two annular corrugations. In this way, it is achieved that when the user moves the cap along his or her skin, an ongoing process in which fresh portions of skin are encountered by the outer annular boundary surface of the outmost annular corrugation of the cap takes place in a smoother manner, wherein lower pressure peaks on the outmost annular corrugation are realized. 
     Advantageously, in the cap according to the present invention, the central surface of the outmost annular corrugation is significantly slanted with respect to the central surface of an annular corrugation which is adjacent to the outmost annular corrugation, wherein an angle between an overall orientation of the central surface of the outmost annular corrugation and an overall orientation of the central surface of the annular corrugation which is adjacent to the outmost annular corrugation is significantly larger than 0°. For example, this angle may be larger than 10°, so that the desired effect of a reduction of pressure peaks on the outmost annular corrugation is actually obtained, and the feeling of comfort during movement of the cap along an area of skin is increased, as the outmost annular corrugation functions as a run-on to the adjacent annular corrugation, as it were. 
     For sake of completeness, it is noted that the concept of overall orientation of the central surface should be understood such as to relate to an average or main orientation of the central surface. In the direction from the center of the cap to the outer periphery of the cap, the central surface may be convexly curved, and in that case, the overall orientation of the central surface should be understood such as to be an orientation of an average tangent plane of the central surface. 
     In a preferred embodiment, the cap according to the present invention comprises at least three annular corrugations, wherein an angle between an overall orientation of the central surface of the outmost annular corrugation and an overall orientation of the central surface of an annular corrugation which is adjacent to the outmost annular corrugation is larger than an angle between an overall orientation of the central surface of an inmost annular corrugation and an overall orientation of the central surface of an annular corrugation which is adjacent to the inmost annular corrugation. It is advantageous if the central surface of the inmost annular corrugation has a less drooping configuration than the central surface of the outmost annular corrugation, in order to achieve that the skin is practically not deformed and subjected to pressure any further when the cap is moved along the skin, and the skin gets contacted by the inmost annular corrugation. 
     In a case in which the central surfaces of the annular corrugations are convexly curved, in a direction from a center of the cap to an outer periphery of the cap, radii of curvature of the central surfaces of different annular corrugations may be substantially the same. In a known cap having three annular corrugations, the central surfaces of the annular corrugations are curved according to an imaginary circle having a certain radius, which is relatively large in order to have a substantially planar appearance of the skin contacting surface of the cap, which comprises these central surfaces. It appears that the feeling of comfort is increased when the central surfaces of the annular corrugations are individually curved, wherein the radii of curvature are relatively small. 
     Furthermore, it appears to be advantageous if the central surface of the outmost annular corrugation is extending at another level than the central surface of an annular corrugation which is adjacent to the outmost annular corrugation, such that, when the cap is seen in an orientation in which it is normally put in contact with the skin, the outmost annular corrugation is somewhat retracted with respect to the adjacent annular corrugation. Likewise, it appears to be advantageous if the central surface of an inmost annular corrugation is extending at another level than the central surface of an annular corrugation which is adjacent to the inmost annular corrugation. In this way, it is realized that an overall shape of a portion of the cap where the annular corrugations are located is toroidal. 
     The cap according to the present invention may be applied in any suitable type of shaving head, and the shaving head having this cap may be applied in any suitable type of shaving apparatus. As the cap according to the present invention is capable of increasing the feeling of comfort for a user, due to shape features, it is very well possible to apply the shaving head having the cap in a shaving apparatus in which the shaving head is flexibly or fixedly connected to a housing portion of the shaving apparatus, and still obtain satisfying results. 
     The above-described and other aspects of the present invention will be apparent from and elucidated with reference to the following description of an embodiment of the cap according to the present invention. 
    
    
     
       The present invention will now be explained in greater detail with reference to the figures, in which equal or similar parts are indicated by the same reference signs, and in which: 
         FIG. 1  diagrammatically shows a perspective view of a shaving apparatus having three shaving heads comprising a cap according to the present invention; 
         FIG. 2  shows a top view of a preferred embodiment of the cap according to the present invention; 
         FIG. 3  shows a side view of a cross-section of the preferred embodiment of the cap according to the present invention; and 
         FIG. 4  diagrammatically illustrates a configuration of central surfaces of annular corrugations of the preferred embodiment of the cap according to the present invention. 
     
    
    
       FIG. 1  shows an electric shaving apparatus  1  having three shaving heads  10 , wherein each shaving head  10  comprises a cap  11  according to the present invention. The shaving heads  10  are mounted in a shaving portion  12   a  of a housing  12  of the shaving apparatus  1 . The housing  12  of the shaving apparatus  1  further comprises a grip portion  12   b , which is intended to be taken hold of by a user of the shaving apparatus  1 . Inside the grip portion  12   b , several components of the shaving apparatus  1 , including an electric motor (not shown) and a battery (not shown) are arranged. In a practical embodiment of the shaving apparatus  1 , the caps  11  of the shaving heads  10  are manufactured from metal, while the housing  12  is manufactured from plastic. 
     Besides a cap  11 , each shaving head  10  of the shaving apparatus  1  comprises a rotatably-arranged cutting member (not shown), which is adapted to cutting through hair, and which is arranged in an interior of the shaving head  10 , close to the cap  11 . The cap  11  comprises a number of apertures  13  for letting through hair to be shaved off to the interior of the shaving head  10 . 
     The shaving apparatus  1  is suitable to be used for the purpose of shaving an area of skin, and is operated as follows. A user takes hold of the grip portion  12   b  of the housing  12  of the shaving apparatus  1 , and places the shaving portion  12   a  of the housing  12  against the skin, such that the caps  11  of the shaving heads  10  contact the skin. Furthermore, the user moves the shaving portion  12   a  along the skin, so that a continuous process during which hairs are caught in the apertures  13  of the caps  11  takes place. In an operative state of the shaving apparatus  1 , the electric motor is switched on, so that the cutting members are driven such as to perform a rotating movement. Due to this movement of the cutting members with respect to the associated caps  11 , hairs which are caught in the apertures  13  of the caps  11  are cut off, wherein these hairs are received in a hair chamber (not shown) which is in communication with the interior of the shaving heads  10 . 
       FIGS. 2 and 3  show views of a preferred embodiment of the cap  11  according to the present invention. 
     The cap  11  has a circular outer periphery  20 . In a practical embodiment of the cap  11 , a diameter of the cap  11  may be in an order of 20 mm. A skin contacting surface  21  of the cap  11 , which is intended to be facing outwardly when the cap  11  is mounted in a shaving head  10 , comprises three annular corrugations  22 ,  23 ,  24 , namely an outmost annular corrugation  22 , a central annular corrugation  23 , and an inmost annular corrugation  24 . In the following, for sake of clarity, a side of the cap  11  where the skin contacting surface  21  is will be regarded as being a top side of the cap  11 . 
     The annular corrugations  22 ,  23 ,  24  are concentrically arranged, and are located around a centre portion  25  of the cap  11 , which has a centrally located recessed portion  26 . In  FIG. 3 , a central axis of the cap  11  is indicated by means of a dot and dash line  27 . 
     Each of the annular corrugations  22 ,  23 ,  24  has an annular central surface  22   a ,  23   a ,  24   a , which is located between an inner annular boundary surface  22   b ,  23   b ,  24   b  on one side and an outer annular boundary surface  22   c ,  23   c ,  24   c  on another side. The annular central surface  22   a ,  23   a ,  24   a  is connected to an associated annular boundary surface  22   b ,  22   c ,  23   b ,  23   c ,  24   b ,  24   c  through a round transition surface  22   d ,  22   e ,  23   d ,  23   e ,  24   d ,  24   e . In the shown example, each transition surface  22   d ,  22   e ,  23   d ,  23   e ,  24   d ,  24   e  is curved according to two different radii, wherein a largest radius is present at the side of the central surface  22   a ,  23   a ,  24   a.    
     A portion of the skin contacting surface  21  of the cap  11  where the inner annular boundary surface  22   b  of the outmost annular corrugation  22  is connected to the outer annular boundary surface  23   c  of the central annular corrugation  23  constitutes an outer recess  28  of the skin contacting surface  21 , whereas a portion of the skin contacting surface  21  where the inner annular boundary surface  23   b  of the central annular corrugation  23  is connected to the outer annular boundary surface  24   c  of the inmost annular corrugation  24  constitutes an inner recess  29  of the skin contacting surface  21 . 
     In a direction from the central axis  27  of the cap  11  to the outer periphery  20  of the cap  11 , the central surfaces  22   a ,  23   a ,  24   a  are convexly curved. In the shown example, the radii of the central surfaces  22   a ,  23   a ,  24   a  are substantially the same. In case the diameter of the cap  11  is in the order of 20 mm, as mentioned in the foregoing, a suitable value of the radii of curvature is 7 mm. 
     A notable feature of the skin contacting surface  21  of the cap  11  is that in the direction from the central axis  27  of the cap  11  to the outer periphery  20  of the cap  11 , the central surface  22   a  of the outmost annular corrugation  22  is slanted downwardly with respect to an imaginary smooth flowing plane following the central surfaces  23   a ,  24   a  of the other annular corrugations  23 ,  24 , which is indicated in  FIG. 3  by means of a thin line  30 . In other words, the central surface  22   a  of the outmost annular corrugation  22  is drooping with respect to the central surfaces  23   a ,  24   a  of the other annular corrugations  23 ,  24 , while the central surface  22   a  of the outmost annular corrugation  22  is significantly slanted with respect to the central surface  23   a  of the central annular corrugation  23 . 
       FIG. 4  diagrammatically illustrates a configuration of the central surfaces  22   a ,  23   a ,  24   a  of the annular corrugations  22 ,  23 ,  24  of the cap  11 . In this diagrammatic depiction, a side view of a cross-section of portions of the annular corrugations  22 ,  23 ,  24  having the central surfaces  22   a ,  23   a ,  24   a  is shown, wherein the central surfaces  22   a ,  23   a ,  24   a  are shown as being planar. Furthermore, the central surface  23   a  of the central annular corrugation  23  is shown in a horizontal orientation. A height difference between the central surface  23   a  of the central annular corrugation  23  and the central surface  22   a  of the outmost annular corrugation  22 , at the side of the central annular corrugation  23 , is indicated under h 1 , and a height difference between the central surface  23   a  of the central annular corrugation  23  and the central surface  24   a  of the inmost annular corrugation  24 , at the side of the central annular corrugation  23 , is indicated under h 2 . An angle of the central surface  22   a  of the outmost annular corrugation  22  to the horizontal is indicated under α 1 , and an angle of the central surface  24   a  of the inmost annular corrugation  24  to the horizontal is indicated under α 2 . 
     In the cap  11  according to the present invention as shown in  FIGS. 2 and 3 , both height differences h 1  and h 2  are larger than zero. The same applies to the angles α 1  and α 2 , wherein the angle α 1  of the central surface  22   a  of the outmost annular corrugation  22  to the horizontal is larger than the angle α 2  of the central surface  24   a  of the inmost annular corrugation  24  to the horizontal. In view of the fact that in the shown example, both angles α 1  and α 2  are larger than zero, it is possible to denote an overall shape of the cap  11  where the annular corrugations  22 ,  23 ,  24  are located as toroidal. 
     In general, it is true that both height differences h 1  and h 2  and the angle α 1  of the central surface  22   a  of the outmost annular corrugation  22  to the horizontal are larger than zero, while the angle α 2  of the central surface  24   a  of the inmost annular corrugation  24  to the horizontal is larger than or equal to zero. 
     It is noted that, in view of the fact that in  FIG. 4 , the central surface  23   a  of the central annular corrugation  23  is oriented according to the horizontal, an angle between an overall orientation of the central surface  22   a  of the outmost annular corrugation  22  and an overall orientation of the central surface  23   a  of the central annular corrugation  23  is equal to the angle α 1  of the central surface  22   a  of the outmost annular corrugation  22  to the horizontal, and an angle between an overall orientation of the central surface  24   a  of the inmost annular corrugation  24  and the overall orientation of the central surface  23   a  of the central annular corrugation  23  is equal to the angle α 2  of the central surface  24   a  of the inmost annular corrugation  24  to the horizontal. 
     The cap  11  according to the present invention is designed for providing a user of the shaving apparatus  1  which is equipped with shaving heads  10  having the cap  11  with a great sensation of comfort. This is mainly achieved on the basis of the shape of the skin contacting surface  21  of the cap  11 , which is adapted to obtaining a smooth passage of the cap  11  over the skin of the user, while avoiding high pressure peaks. In other words, the cap  11  has a comfort profile, wherein an important factor contributing to the feeling of comfort is the drooping configuration of the central surface  22   a  of the outmost annular corrugation  22  with respect to the central surfaces  23   a ,  24   a  of the other annular corrugations  23 ,  24 . For example, in the preferred embodiment of the cap  11  according to the present invention as shown, the angle between the overall orientation of the central surface  22   a  of the outmost annular corrugation  22  and the overall orientation of the central surface  23   a  of the central annular corrugation  23  is approximately 14°. In general, satisfying results are obtained if this angle is larger than 10°, but that does not alter the fact that the angle may also have a value which is between 0° and 10°. 
     Other important factors contributing to a feeling of comfort are the convexly curved shape of the central surfaces  22   a ,  23   a ,  24   a  of the annular corrugations  22 ,  23 ,  24 , and the toroid overall shape of the portion of the cap  11  where the annular corrugations  22 ,  23 ,  24  are located. 
     Particularly, in the shown example of the cap  11  according to the present invention, the angle α 1  of the central surface  22   a  of the outmost annular corrugation  22  to the horizontal is 14°, the angle α 2  of the central surface  24   a  of the inmost annular corrugation  24  to the horizontal is 1°, the height difference h 1  between the central surface  23   a  of the central annular corrugation  23  and the central surface  22   a  of the outmost annular corrugation  22 , at the side of the central annular corrugation  23 , is 0.09 mm, and the height difference h 2  between the central surface  23   a  of the central annular corrugation  23  and the central surface  24   a  of the inmost annular corrugation  24 , at the side of the central annular corrugation  23 , is 0.01 mm. Other suitable combinations of values of the angles and height differences as mentioned are feasible within the scope of the present invention. 
     The cap  11  is suitable to be applied in many types of shaving heads  10  and shaving apparatus  1  comprising at least one shaving head  10 . In view of the fact that the cap  11  according to the present invention as such is capable of causing a user to experience a great feeling of comfort, the cap  11  is particularly suitable to be applied in shaving heads  10  which are flexibly or fixedly connected to the shaving portion  12   a  of the housing  12  of a shaving apparatus  1 . It is noted that in such a shaving apparatus  1 , the shaving portion  12   a  of the housing  12  may be arranged such as to be movable to a limited extent with respect to the grip portion  12   b  of the housing  12 , but this is not essential. 
     It will be clear to a person skilled in the art that the scope of the present invention is not limited to the example discussed in the foregoing, but that several amendments and modifications thereof are possible without deviating from the scope of the present invention as defined in the attached claims. While the present invention has been illustrated and described in detail in the figures and the description, such illustration and description are to be considered illustrative or exemplary only, and not restrictive. The present invention is not limited to the disclosed embodiment. 
     In this respect, it is noted that the scope of the present invention is not restricted to caps  11  having three annular corrugations  22 ,  23 ,  24 . The present invention also relates to caps having only two annular corrugations, or caps having more than three annular corrugations  22 ,  23 ,  24 . Furthermore, it is noted that the number of shaving heads  10  of a shaving apparatus  1  in which the present invention is applied may be chosen freely. 
     Variations to the disclosed embodiment can be understood and effected by a person skilled in the art in practicing the claimed invention, from a study of the figures, the description and the attached 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. 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 of the present invention. 
     In the foregoing, a cap  11  is disclosed, which is suitable to be applied in a shaving head  10  of a shaving apparatus  1 , wherein the shaving head  10  further comprises a movably arranged cutting member adapted to cutting through hair. The cap  11  has a skin contacting surface  21  which comprises at least two annular corrugations  22 ,  23 ,  24 . In an area of the cap  11  where these annular corrugations  22 ,  23 ,  24  are located, the cap  11  is provided with apertures  13  for catching and letting through hair to be cut off. 
     The shape of the skin contacting surface  21  of the cap  11  is adapted to realizing a high feeling of comfort for a user of a shaving apparatus  1  which is equipped with at least one shaving head  10  comprising the cap  11 . A factor contributing to the feeling of comfort is that an annular central surface  22   a  of an outmost annular corrugation  22  has an orientation which is out of line with an expected course of an imaginary smooth flowing plane  30  following the at least one central surface  23   a ,  24   a  of the at least one other annular corrugation  23 ,  24 , wherein a drooping configuration of the central surface  22   a  of the outmost annular corrugation  22  with respect to the at least one central surface  23   a ,  24   a  of the at least one other annular corrugation  23 ,  24  is realized.