Abstract:
A pivoting arrangement for a shaving device, comprising a pivoting member ( 10 ), adapted to support a shaving head, a cradle ( 11 ), pivotally supporting the pivoting member, and a spring loading arrangement ( 13 ) arranged to bias the pivoting member in a resting position. The spring loading arrangement has a limited active range, so that, when the pivoting member is brought out of the resting position in a first pivoting direction, the spring loading arrangement is prevented from interacting with the pivoting member in a first point of action ( 14   a ), and when the pivoting member is brought out of the resting position in a second pivoting direction, the spring loading arrangement is prevented from interacting with the pivoting member in a second point of action ( 14   b ). As a result, the resting position will not be dependent on e.g. the spring constants of different springs in the spring loading arrangement. The resting position will thus be more exactly defined, and exhibit less variation than conventional solutions. Also, the total force acting on the pivoting member will be reduced, thus causing less friction, also serving to improve the predictability of the arrangement.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a pivoting arrangement for a device having a contour following function such as e.g. a shaving device. 
     BACKGROUND OF THE INVENTION 
     Conventional shaving and grooming devices are sometimes equipped with a pivoting arrangement providing a contour following function. Contour following functions are known from other devices as well such as epilators, skin rejuvenation, wrinkle treatment and trimming devices. In some pivoting arrangements, a moving part of the shaving head is spring loaded towards an extreme angular position, so that it assumes this extreme position when it is not submitted to any external forces. 
     In other pivoting arrangements a moving part of the shaving head is arranged to assume a predefined resting position, e.g. a middle position, when it is not submitted to any external forces. This resting position can be spring loaded. 
     Such a conventional middle position pivoting arrangement is known from U.S. Pat. No. 6,301,786, and is schematically shown in  FIG. 1 . A pivoting member  1  is supported by a supporting member or cradle  2 , allowing it to pivot around an axis A. Two (or more) spring members  3  are arranged at the base plate  4  of the supporting member or cradle  2 . When the pivoting member is in an unbiased resting position, as shown in  FIG. 1 , both spring members  3  are preloaded against the pivoting member  1 . When the pivoting member is forced out of its resting position, it will depress one of the springs further, while extending the other spring. The force of the depressed spring will now become greater than the force from the extended spring, thus offsetting the equilibrium of the springs, and creating a net force acting on the pivoting member towards the middle position. 
     A potential problem with such conventional pivoting arrangements is that if the two springs have, or grow to have, slightly different spring constants, the equilibrium of the springs may become permanently offset, so that the pivoting member will fail to resume its middle position after being depressed. As a result, the resting position of the pivoting member will no longer be the middle position, but a slightly angled position. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to overcome this problem, and to provide a pivoting arrangement for a device having a contour following function such as e.g. a shaving device with less variation of the resting position. 
     This and other objects are achieved by a pivoting arrangement for a device having a contour following function such as e.g. a shaving device, comprising a pivoting member, adapted to support a shaving head, a cradle, pivotally supporting the pivoting member, and a spring loading arrangement comprising at least one deformable spring element, and arranged to interact with the pivoting member in a first point of action to exert a force acting to move the pivoting member in a first pivoting direction, and in a second point of action to exert a force acting to move the pivoting member in a second pivoting direction, the spring loading arrangement thereby biasing the pivoting member in a resting position. The spring loading arrangement further has a limited active range, so that, when the pivoting member is brought out of the resting position in the first pivoting direction, the spring loading arrangement is prevented from interacting with the pivoting member in the first point of action, and when the pivoting member is brought out of the resting position in the second pivoting direction, the spring loading arrangement is prevented from interacting with the pivoting member in the second point of action. 
     The active range of the spring loading arrangement is thus limited, so that the spring loading arrangement will only exert forces that act to return the pivoting member to its resting position. As a result, the resting position will not be dependent on e.g. the spring constants of different springs in the spring loading arrangement. The resting position will thus be more exactly defined, and exhibit less variation than conventional solutions. Also, the total force acting on the pivoting member will be reduced, thus causing less friction, also serving to improve the predictability of the arrangement. 
     The term “resting position” should here be interpreted primarily as a desired “default” position of the pivoting member, but also a small angular range around this position. In other words, it is possible that the pivoting member may be moved slightly in its resting position, without any force being exerted by the spring loading arrangement. Such a “free” angular range may be caused by play in the mechanical construction, or be a result of wear. 
     The spring loading arrangement can comprise at least two abutments, against which said spring loading arrangement is arranged to abut, thereby limiting the active range of the spring loading arrangement. The abutments thus serve to prevent the spring loading arrangement from interacting with the pivoting arrangement. 
     The spring loading arrangement may be preloaded against the abutments when the pivoting member is in its resting position. Such preloading will ensure that a well defined force is exerted by the spring member in its active range, i.e. when acting to return the pivoting member to the resting position. 
     According to one embodiment, the spring loading arrangement comprises at least two deformable spring elements, each arranged to interact with the pivoting member in one of the points of action. This can be a mechanically simple way to realize an embodiment of the present invention. 
     The spring elements may have different spring coefficients. As a result, a greater force will be required in order to pivot the pivoting member in a first direction than in a second direction. This may be advantageous in specific applications of the pivoting arrangement. 
     An abutment is an efficient way to restrict the active range of a deformable spring member, such as a coil spring, a leaf spring, or a torsion spring. The spring member will be active until it abuts the abutment, which thus limits the expansion (or contraction) of the spring member. By arranging the spring and the abutment so that this occurs at the resting position, the advantages mentioned above will be achieved. 
     For example, each abutment can be arranged to cooperate with a spring element such that, when the pivoting member is brought out of the resting position in one direction, the spring element is deformed, thereby exerting a force on the pivoting member, and, when the pivoting member is brought out of the resting position in another direction, the spring element abuts the abutment, and is brought out of contact with the pivoting member. 
     The deformable spring element can be arranged to be compressed when the pivoting member is brought out of the resting position in the first direction, and the abutment can then be arranged to restrict extraction of the deformable spring element. Alternatively, the deformable spring element can be arranged to be extracted when the pivoting member is brought out of the resting position in the first direction, and the abutment can then be arranged to restrict compression of the deformable spring element. 
     According to another embodiment, the spring loading arrangement comprises a force transfer element arranged to interact with said pivoting member in said first and second points of action and a deformable spring element arranged to bias the force transfer element towards the pivoting member, so that, when the pivoting member is brought out of its resting position in the first direction, the pivoting member engages the force transfer element in said second point of action, and moves the force transfer element so as to separate the force transfer element from the pivoting member in said first point of action. 
     According to this embodiment, only one spring element is required, as the force transfer element transfer the force from this spring element to all points of action with the pivoting member. In this case, the spring loading arrangement can be preloaded against the pivoting member in the resting position, eliminating the need for separate abutments. 
     According to a further embodiment, the cradle is pivotable around a first axis, and the pivoting arrangement may further comprise an outer cradle in which the cradle is pivotable around a second axis and a second spring loading arrangement, arranged to bias said cradle in a resting position. The pivoting member will thus be movable in any direction. 
     It is noted that the invention relates to all possible combinations of features recited in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing a currently preferred embodiment of the invention. 
         FIG. 1  shows a pivoting arrangement according to prior art. 
         FIG. 2 a    shows a pivoting arrangement according to a first embodiment of the present invention, in a resting position. 
         FIG. 2 b    shows the pivoting arrangement in  FIG. 2 a   , in a working position. 
         FIG. 3 a    shows a pivoting arrangement according to a second embodiment of the present invention, in a resting position. 
         FIG. 3 b    shows the pivoting arrangement in  FIG. 3 a   , in a working position. 
         FIG. 4 a    shows a pivoting arrangement according to a third embodiment of the present invention, in a resting position. 
         FIG. 4 b    shows the pivoting arrangement in  FIG. 4 a   , in a working position. 
         FIG. 5 a    shows a pivoting arrangement according to a fourth embodiment of the present invention, having two axis of rotation, in a resting position. 
         FIG. 5 b    shows the pivoting arrangement in  FIG. 5 a   , in a first working position rotated around a first axis. 
         FIG. 5 c    shows the pivoting arrangement in  FIG. 5 a   , in a second working position rotated around a second axis. 
         FIG. 6  shows an alternative arrangement of the leaf spring arrangement in  FIG. 5   a.    
         FIG. 7 a    shows an exploded view of a pivoting arrangement according to a fourth embodiment of the invention, having two axis of rotation. 
         FIG. 7 b    shows selected parts of the pivoting arrangement in  FIG. 7 a   , with the cradle rotated around the axis A 1 . 
         FIG. 7 c    shows selected parts of the pivoting arrangement in  FIG. 7 a   , with the pivoting member rotated around the axis A 2 . 
         FIG. 8  shows a pivoting arrangement according to another embodiment with the pivoting member rotated around axis A. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The following embodiments of pivoting arrangements according to the present invention may be useful in various types device having a contour following function such as e.g. shaving or grooming devices, where a contour following head such as e.g. a shaving head may be supported by the pivoting member, so as to allow for a contour following function. The following embodiments show the invention being implemented in a device having a shaving function. However, it should be noted that the invention is not limited to shaving devices as such and that the embodiments show non-limiting examples of the invention. Therefore, the details of the shaving device itself and its function will be described only very briefly, as they are not immediately relevant for the description of the present invention. 
     The pivoting arrangement shown in  FIG. 2 a    comprises a pivoting member  10 , which is pivotally arranged in a cradle  11 . The cradle  11  is in turn arranged on a supporting structure, here referred to as a base plate  12 . The pivoting member  10  is adapted to support a shaving head (not shown), and may be provided with a pre-trimmer (not shown). Depending on the type of device, and the function of the pivoting member, the pivoting member  10  may be pivotable around a point or axis A. For this purpose, the pivoting member may rest on a suspension point or axle, which it is pivotable around. Alternatively it may be guided by e.g. grooves in the cradle  11 , so as to be pivotable around an imaginary pivoting point or axis. 
     In order to keep the pivoting member in a neutral resting position ( FIG. 2 a   ), the pivoting member  10  is spring loaded by a spring loading arrangement  13 , arranged to exert a force on both the cradle and the pivoting member. The spring loading arrangement can interact with the pivoting member  10  in at least two points of action  14   a ,  14   b , to allow exertion of force in at least two directions of rotation around the pivoting axis A. If the pivoting member is pivotable around a point, the spring loading arrangement can preferably interact with the pivoting member in at least three points of action. 
     In the embodiment in  FIG. 2 a - b   , the spring loading arrangement  13  comprises two coil springs  15   a ,  15   b  that are clamped between the cradle  11  and the base plate  12 . As the cradle  11  is fixed in relation to the base plate  12 , the springs can exert a force on both the cradle  11  and the pivoting member  10 . 
     The spring loading arrangement may further comprise a force reliving structure. Again referring to the embodiment in  FIG. 2 a - b   , the force relieving structure here comprises two abutments  16  formed by protruding portions of the cradle  11 , against which the springs are preloaded. As is clear from  FIG. 2 a   , the abutments  16  are located so that the pivoting member  10  in the resting position will be in level with the abutments. A surface  10   a  of the pivoting member  10  will thus be immediately adjacent, and possibly in contact with, the preloaded springs. 
     Turning to  FIG. 2 b   , the pivoting member  10  has now been rotated around the axis A, and brought out of its resting position. On the left side, the surface  10   a  of the pivoting member has then moved away from the abutment  16  against which the spring  15   a  abuts, and this spring  15  is therefore prevented from interacting with the pivoting member  10 . On the right side, the spring  15   b  has been further depressed by the surface  10   a  of the pivoting member, and therefore exerts a force F on the pivoting member  10  in the point of action  14   b , acting to return the pivoting member to the resting position. 
     The skilled person will realize that the springs  15   a ,  15   b  in  FIG. 2 a - b    also could be arranged above the points of actions, so that the spring on the left side is depressed as this part of the pivoting member  10  moves upwards (in the reference frame of  FIG. 2 b   ). In other words, although in  FIG. 2   a - b  the springs  15   a  and  15   b  are arranged between the base plate  12  and the cradle  11 , other configurations are possible as well. E.g. configurations wherein the springs are located at the top sides of the cradle 
     In another embodiment, illustrated in  FIG. 3 a - b   , the two springs have been substituted by one spring  17 , arranged with each of its two ends  17   a ,  17   b  in one of the points of action  14   a ,  14   b . As is clear from  FIGS. 3 a - b   , the function of the spring and abutments is very similar to that described with reference to  FIG. 2 a - b   . In  FIG. 3 b   , when the pivoting member  10  is rotated around the axis A, the left end  17   a  of the spring  17  abuts against the abutment  16 . The right end  17   b  of the spring  17  is depressed by the pivoting member  10 , and therefore exerts a force F on the pivoting member  10  in the point of action  14   b , acting to return the pivoting member to the resting position. 
     In yet another embodiment, illustrated in  FIG. 4 a - b   , the spring loading arrangement comprises a force transfer element in the form of a plate  18 , preloaded against the abutments  16  by a single spring element  15 . When the pivoting member is brought out of its resting position in  FIG. 4 a   , into a working position in  FIG. 4 b   , one side of the pivoting member  10  pushes down on the plate  18 , thereby causing the spring to exert a force F on the pivoting member in a point of action  14   b  acting to return it to its resting position. The other side of the pivoting member is moved away from and out of contact with the plate  18 , which here abuts against the abutment  16 . The resulting function is much similar to that in  FIG. 2 a   - b.    
       FIG. 5 a - c    shows a further embodiment, according to which the pivoting arrangement is able to allow the pivoting member  20  to pivot around two different axes. For this purpose, the pivoting member  20  is suspended by two axles  21  in the cradle  22 , so as to be pivotable around a first axis A 1 . The cradle is then in itself supported by the supporting structure, here referred to as an outer cradle  23 , to be pivotable around a second axis A 2 . The cradle  22  can be guided by grooves (not shown) in the outer cradle  23 , so as to be movable in relation to the outer cradle  23 , or be suspended by additional axles  24 . 
     The pivoting member  20  is adapted to follow a contour following element. The pivoting member  20  having mounted thereto, two axles stubs  21  which are arranged and exclusively mounted to respective first and second distal ends of the pivoting member  20 .  FIG. 5A-5C  shows one of the two axles  21  connected to a first distal end of the pivoting member  20 . The cradle  22  includes a pair of end panels and a pair of side panels, where the end panels and the side panels are interconnected at peripheral portions thereof so as to define the cradle  22 , configured as a cavity for partially receiving the pivoting member. The cradle  22  further includes two recessed portions located at the first and second distal ends along the axis A 1 , where the recessed portions are configured to receive the respective first and second axle stubs  21  of the pivoting member  20 . 
     The spring loading arrangement in  FIG. 5  comprises a leaf spring  26 , which is fixed to the underside  22   a  of the cradle  22  by two clamps  27 , preferably preloading the leaf spring  26  against the cradle  22 . In the resting position ( FIG. 5 a   ) the two ends  26   a ,  26   b  of the leaf spring are arranged to be located immediately adjacent to the surface  23   a  of the outer cradle  23 . As the pivoting member is rotated ( FIG. 5 b   ), one end  26   a  of the leaf spring is “lifted” so as to lose contact with the surface of the outer cradle  23 . The other end  26   b  is pressed more firmly against the outer cradle  23 , and will cause the leaf spring  26  to exert a force on the cradle  22  acting to return it to the resting position. 
     In analogy to the embodiment in  FIG. 2 , the leaf spring  26  could be replaced by two or more leaf springs, each having only one point of action with the pivoting member. 
     The spring arrangement in  FIG. 5  further comprises a torsion spring  28 , arranged around the axle stub  21  of the pivoting member  20 , and preloaded in one rotational direction by abutments  29  on the inner wall of the cradle  22 . The pivoting member  20  is also provided with abutments  30   a - b  on either side of the spring  28 , arranged to cooperate with the torsion spring when the pivoting member  20  is rotated.  FIG. 5 c    illustrates rotation of the pivoting member  20 . One of the abutments  30   a  is moved towards and compresses the torsion spring, thus creating a force acting to return the pivoting member to its resting position. The other abutment  30   b  is moved out of contact with the torsion spring, which on this side remains preloaded against the abutment  29 . 
       FIG. 6  is a perspective view of a pivoting arrangement similar to that in  FIG. 5 a - c   , where the upper part, including the pivoting member  20  and the cradle  22 , has been exploded away from the outer cradle  23 . As a result, only the part of the spring loading arrangement that acts between the cradle  22  and the outer cradle  23  is shown in detail. In this case, the leaf spring is formed by an oval shaped metal element  32 . This spring element  32  is fixed to the outer cradle  23  by a holder in the form of a metal plate  33 , which is fixed (by screws or the like) to the outer cradle  23 . The outer ends  33   a ,  33   b  of the plate  33  are formed to grip the ends  32   a ,  32   b  of the spring element  32 , thereby acting as abutments that pretension the element  32 . The cradle  22  is arranged to be guided by the edges  34  of the outer cradle, to be pivotable around an axis A 2 . Further, the underside of the cradle  22  is arranged to rest on the oval element, at points of action on either end of the spring element  32 . 
     When the cradle  22  is brought out of its resting position, one end of the cradle  22  will move towards the outer cradle  23 , and at his end it will depress the spring element  32 , thereby creating a force acting to return the cradle  22  to its resting position. The opposite side of the cradle  22  will move away from the outer cradle  23 , and thus loose contact with the spring element  32 , which here will abut against the holder  33 . 
     It may be noted that the spring element  32  in  FIG. 6  is oriented in an opposite fashion compared to the leaf spring  26  in  FIG. 5 , but has an otherwise similar function. 
       FIG. 7 a    shows yet another embodiment of a double axis pivoting arrangement according to the present invention. Similar to the embodiments in  FIGS. 5 and 6 , the pivoting arrangement here comprises a pivoting member  41 , a cradle  42 , and an outer cradle  43 . The cradle has two axles  53 , arranged to cooperate with holes  54  in the pivoting member  41 , to allow rotation of the pivoting member  41  around an axis A 1 . The cradle has two axles  51  arranged to cooperate with holes  52  in the outer cradle  43 , to allow rotation of the cradle  42  around an axis A 2 . 
     The spring loading arrangement is formed by two spring elements  44 , each in the form of a substantially U-shaped wire, fitted to the cradle by means of protrusions  45  cooperating with the wire to hold it in place, e.g. by snap fitting. 
     Each wire  44  is arranged with its legs  46   a ,  46   b  extending from the center of the cradle towards its outer ends. One of the legs  46   a  extends into an elongated grove  47  in an end plate  48  of the cradle  42 , and is preloaded to abut against the outer edge  47   a  of this grove. The underside of the pivoting member  41  further has an indentation  48  that is formed to cooperate with the leg  46   a . The other leg  46   b  has an end portion  49  that is bent outwards, and adapted to, when the cradle  42  is mounted in the outer cradle  43 , extend into a groove  50  in the outer cradle, and be in contact with the upper edge of the groove  50 . 
     With reference to  FIG. 7 b   , when the cradle  42  is rotated around the axis A 2 , the two legs  46   b  will serve as a spring loading arrangement similar to that described in relation to  FIGS. 5 a  and 5 b   . On the side of the cradle  42  that is moved away from the outer cradle  43 , the end portion  49  of the leg  46   b  will be pressed against the upper edge of the groove  50 , thus causing a force to be exerted on the cradle  42  to return it to the resting position. On the other side of the cradle  42 , moving towards the outer cradle  43 , the portion  49  will be brought out of contact with the groove  50 , thus preventing any force to be exerted. 
     Turning now to  FIG. 7 c   , when the pivoting member  41  is rotated around axis A 1 , one of the indentations  48   a  will engage with the preloaded leg  46   a , thereby causing a force to be exerted on the pivoting member  41 . The other indentation  48   b , on the other side of the pivoting member, will move away from the corresponding leg  46   a , thus avoiding any force. 
     The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, the shape of the various components may be modified, as can the type and number of spring elements.