Patent Publication Number: US-9895817-B2

Title: Shaver

Description:
This application is a national stage application of International Application No. PCT/EP2012/076805, filed on Dec. 21, 2012, the entire contents of which are incorporated herein by reference. 
     FIELD OF INVENTION 
     The embodiment of the present invention relates to a shaver with interchangeable cartridges, and to cartridges and head and handle assembly for such a shaver. 
     More particularly, the embodiments of the present invention relate to a shaver that includes: 
     a handle with an elongated body terminating in a mounting portion for retaining a shaver head, 
     a shaver head adapted to accommodate an interchangeable shaving cartridge, 
     a lock-and-release mechanism to enable the interchangeable shaving cartridge to be loaded and ejected from the shaver head, and 
     an interchangeable cartridge containing one or more blades. 
     Such a shaver enables the user to replace the cartridge once the blade or blades become worn, while the handle and the shaver head can be kept and reused. 
     BACKGROUND OF THE INVENTION 
     The removal from the shaver head of the interchangeable blade cartridges, such as those disclosed in e.g. EP2195145, usually requires the user to press or pull the cartridge to actually displace the cartridge. This means that to replace the cartridge, the user needs to encounter the cartridge by his/her fingers. Therefore, the risk of the injury of the user is increased. 
     SUMMARY OF THE INVENTION 
     A shaver is provided, the shaver that includes a handle with an elongated handgrip portion and a mounting portion, a shaver head, the shaver head being attached to the mounting portion, a removable cartridge, the cartridge comprising at least one blade, the at least one blade having a length, the cartridge being adapted to be attached to the shaver head and removed from the shaver head, a rotating lock provided on the shaver head, the rotating lock being adapted to removably attach the cartridge to the shaver head, wherein the rotating lock is adapted to rotate about an axis parallel to the length of the at least one blade, thus defining a neutral position and a rotated position, wherein the rotating lock in the neutral position attaches the cartridge to the shaver head, and the rotating lock in the rotated position releases the cartridge from the shaver head. 
     In some embodiments, one may also use one or more of the following features: 
     the shaver head may be attached pivotally to the mounting portion, 
     the shaver head further comprises a bottom part, and the rotating lock is provided in the bottom part, 
     the shaver head further comprises a pair of holding pegs, and the holding pegs facilitate the rotation of the rotating lock, 
     the cartridge is ejected in a direction parallel to the direction of shaving, 
     the rotating lock is provided as a rotating bar, 
     the rotating lock comprises an elongated body, at least one projection, protruding in a direction away from the shaving plane, a pair of cavities positioned at the ends of the elongated body and being adapted to attach the rotating lock to the haver head, and at least one retention cavity, 
     the rotating lock comprises an elongated body, a pair of projections, protruding in a direction away from the shaving plane, a pair of cavities positioned at the ends of the elongated body and being adapted to attach the rotating lock to the haver head, and a pair of retention cavities, 
     the shaver head further comprises a return spring, the return spring being adapted to return the rotating lock to the neutral position, 
     the shaver head further comprises at least one ejection button, the ejection button being adapted to eject the cartridge from the shaver head, 
     the shaver head further comprises at least one ejection spring, the ejection spring cooperating with the at least one ejection button, 
     the handle further comprises a slidable button, the button that includes a pusher, the pusher being adapted to encounter the projections of the rotating lock and thus release the cartridge, 
     the cartridge further comprises a holder, and the retention cavities of the rotating lock and the holder cooperate to attach the cartridge to the shaver head, 
     the shaver head further comprises lateral walls, the lateral walls comprise guide tracks, the cartridge further comprises lateral walls, the lateral walls comprise guide tracks, and the guide tracks of the cartridge are adapted to cooperate with guide tracks of the shaver head. 
     In another aspect of the present invention, a cartridge is provided, the cartridge comprising a holder, and the holder takes a form of at least one hook. 
     In some embodiments, one may use one or more of the following features: 
     the cartridge comprises at least one blade, the at least one blade is mounted movably, 
     the cartridge further comprises a top wall and a shaving aid, the shaving aid being positioned in the top wall. 
     In yet another aspect of the present invention, a head and handle assembly for a shaver is provided, the head and handle assembly that includes a handle with an elongated handgrip portion and a mounting portion, a shaver head, the shaver head being adapted to receive a cartridge, the shaver head being attached to the mounting portion, a rotating lock provided on the shaver head, the rotating lock being adapted to removably attach the cartridge to the shaver head, wherein the rotating lock is adapted to rotate about an axis parallel to the length of the at least one blade, thus defining a neutral position and a rotated position, wherein the rotating lock in the neutral position is adapted to attach the cartridge to the shaver head, and the rotating lock in the rotated position is adapted to release the cartridge from the shaver head. 
     In some embodiments, one may also use one or more of the following features: 
     the shaver head may be attached pivotally to the mounting portion, 
     the shaver head further comprises a bottom part, and the rotating lock is provided in the bottom part, 
     the rotating lock comprises an elongated body, at least one projection, protruding in a direction away from the shaving plane, a pair of cavities positioned at the ends of the elongated body and being adapted to attach the rotating lock to the haver head, and at least one retention cavity, 
     the handle further comprises a slidable button, the button that includes a pusher, the pusher being adapted to encounter the projections of the rotating lock and thus release the cartridge. 
     With these features, when the cartridge is to be removed from the shaver head, it is more easily ejected from the shaver head. The user does not have to push or pull the cartridge and the risk of injury of the user is lowered. Moreover, as only the cartridge is replaced when the blades become worn, instead of replacing the whole shaver head, the costs of such shaver are kept lower. Further, as only the cartridge is replaced, the shaver is both easier to manufacture and more environment friendly, as the amount of material to be replaced (and disposed of) is reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics and advantages of the invention will readily appear from the following description of one of its embodiments, provided as a non-limitative examples, and of the accompanying drawings. 
       On the drawings: 
         FIG. 1 a    shows an overall view of the shaver from the front side 
         FIG. 1 b    shows an overall view of the shaver from the back side 
         FIG. 2 a    shows a front portion of the handle 
         FIG. 2 b    shows a front portion of the handle with a cam follower and a spring 
         FIG. 3 a    shows a front view of a cartridge and a shaver head upon the insertion of the cartridge 
         FIG. 3 b    shows a cross-section of the shaver head through a return spring, along line Ib 
         FIG. 3 c    shows a cross-section of the shaver head through the features attaching the cartridge to the shaver head, along line Ic 
         FIG. 3 d    shows a cross-section of the shaver head through projections provided on a rotating bar, along line Id 
         FIG. 4 a    shows the shaver head without the cartridge and without movable components, as seen from the front 
         FIG. 4 b    shows a detail of a rotating lock 
         FIG. 4 c    shows the shaver head without the rotating lock, as seen from the front 
         FIG. 4 d    shows the shaver head when assembled, as seen from the front 
         FIG. 4 e    shows the shaver head when assembled, as seen from the back 
         FIG. 5  is a back view of the cartridge 
         FIG. 6 a    shows an exploded view of the shaver head 
         FIG. 6 b    shows an exploded view of the shaver head 
         FIG. 7 a    shows a top side of a button 
         FIG. 7 b    shows an overall view of a button 
     
    
    
     On the different Figures, the same reference signs designate like or similar elements. 
     DETAILED DESCRIPTION 
       FIGS. 1 a  and 1 b    show an example of a shaver according to the present invention. The shaver comprises a handle  20 , a shaver head  40  and a cartridge  60 , which accommodates one or more blades  63 . On the example shown on the Figures, there are four blades. However, the cartridge may also use more or less of blades. 
     The cartridge  60  (shown on  FIGS. 3 a    and  5 ) is formed as a frame with a top wall  61 , two lateral walls  62 , bottom wall  67  and a back structure  68  (shown in detail on  FIG. 5 ). The top wall  61  and the bottom wall  67  are elongated and connected by the lateral walls  62 . The frame of the cartridge  60  may be molded out of plastic; preferably, the frame is one-piece. The blades  63  extend between the lateral walls  62 , parallel to the top wall  61  and the bottom wall  67 . The blades  63  may be made from bent sheet metal, or, preferably, they may be straight and supported with blade supports (not shown). The blades  63  and/or the blade supports  63 A are then accommodated in seats (not shown) provided in the lateral walls  62 . Moreover, the blades may for instance be placed movably. The lateral walls  62  may be provided with elastic fingers  64 , extending towards the insides of the cartridge frame, in a direction parallel to the blades  63 , and supporting movably the blades  63 . The blades  63  may be held in the cartridge by a pair of bent metal strips  66 , which encircle the ends of the blades  63  and thus hold them in place. In the top wall  61 , lying generally in a plane defined by the blade edges, a shaving aid  61 A may be provided. In other embodiments, the blades may be fixed. 
     The handle  20  has an elongated handgrip portion (not shown) which may be provided with features that enhance grip of the user and help prevent slipping, such as ribs, pegs, elastomeric parts and the like. The handle  20  is preferably molded out of a plastic material. The handle  20  is terminated in two yokes  21  extending from the handle, as shown on  FIG. 2 . The yokes  21  end in a mounting portion, which may be provided in a form of shell bearings  22 . The shell bearings  22  then cooperate with complementary depressions  41  provided on the shaver head  40 . The shell bearings  22  and the complementary depressions  41  together enable the shaver head  40  to pivot about an axis parallel to the length of the blades  63 . Alternatively, the shell bearings  22  may be replaced by hinges, pins or other pivoting means; the shaver head  40  may also be attached to the handle  20  without any pivoting means. Here, only the pivoting head will be described. 
     The yokes  21  further define a gap  23 , positioned between the yokes  21 . The gap  23  accommodates a cam follower  24 . The cam follower  24  has a bifurcated end; the two branches cooperate with a rest  43 A provided on back wall  43  of the shaver head  40 , therefore enabling the shaver head  40  to be returned to the neutral position. The cam follower  24  is operated by a coil spring  36 , which is preferably made of metal. 
     An example of a shaver head  40  is shown on  FIGS. 3 a  to 3 d   ,  FIGS. 4 a  to 4 e    and  FIGS. 6 a  and 6 b   . The shaver head comprises a back wall  43 , a bottom part  46  and lateral walls  42 . The front wall  42  may include a skin engaging element or a guard (not shown), preferably made in an elastomeric material. The back wall  43  comprises depressions  41 , which accommodate shell bearings  22 , positioned at the end of the handle  20 . On the back wall  43 , there is also a rest  43 A, cooperating with the cam follower  24 . 
     The shaver head  40  forms a seating where the cartridge  60  can be accommodated (detail of such seating is shown on  FIGS. 3 a  and 4 d   ). The cartridge  60  is preferably inserted from the side opposing the bottom part  46 , as shown on  FIG. 3 a   , generally in a direction of shaving. The lateral walls  42  include guide tracks  42 A, formed as grooves on the insides of the lateral walls  42 . Once the cartridge  60  is inserted into the shaver head, the guide tracks  42 A are encountered by guide tracks  62 A provided as protrusions on the lateral walls  62  of the cartridge  60  and the cartridge  60  is guided to its seating. The risk of wrong insertion of the cartridge  60  is thus lowered. 
     The bottom part  46  of the shaver head  40  is positioned between a bottom wall  46 A and a seating wall  46 B. The bottom part  46  comprises a holding mechanism, adapted to attach the cartridge  60  to the shaver head  40 . The holding mechanism loads, retains, and ejects the cartridge  60 . The mechanism preferably comprises a rotating lock  45  and a pair of holding pegs  42 B. The rotating lock  45  may be provided behind the shaving guard (variant not shown), or may itself constitute at least part of the shaving guard. In the example shown in the Figures, the rotating lock is provided as a one-piece rotating bar, which may serve as a guard bar. However, there are other possibilities. The rotating lock, when in the form of a rotating bar serving as a guide bar, may be provided for example as a co-injection component which bears fins. The rotating lock may also be provided in more than one piece. The rotating lock may be rotating as a solid body about a rotating axis. The rotating lock may also perform a torsional movement, where only a part of the rotating bar is actually rotated. 
     The mechanism may also comprise at least one ejection button  51 , at least one ejection spring  52 , and at least one return spring  56 . The bottom part  46  may further comprise a slot  54 , accommodating the return spring  56 . The bottom part  46  preferably further comprises a number of cavities  57 , accommodating the ejection buttons  51  and the ejection springs  52 ; the number of cavities  57  preferably corresponds to the number of ejection buttons  51  and ejection springs  52 . The seating wall  46 B preferably comprises at least one seating slot  55 . The bottom part  46  preferably further comprises at least one back opening  53 . 
     In an example shown on  FIGS. 3 b  to 3 d , 4 a  to 4 e , 6 a  and 6 b   , the holding mechanism comprises a pair of ejection buttons  51 , a pair of ejection springs  52 , one return spring  56 , a pair of seating slots  55 , and a pair of back openings  53 . The ejection springs  52  are provided in a form of coil springs, but alternatively may be replaced by leaf springs or else. The return spring  56  is provided as a leaf spring. The return spring  56  may be also provided in a form of one or more helical or rotational springs or else. 
     In the bottom part of the lateral walls  42  of the shaver head, adjacent the bottom part  46  of the shaver head  40 , a pair of openings  42 C is positioned. The openings  42 C are preferably circular and aligned so as to form an axis parallel with the bottom wall  46  of the shaver head. The axis is also parallel to the length of the blades, and parallel to the pivoting axis. In each of the openings  52 C, a holding peg  42 B is provided. The holding pegs  42 B preferably take an overall shape of a cylinder, with a circular base. The holding pegs  42 B can also take any other suitable shape that allows axial rotation, such as projections with a base in a shape of a square, a rectangle, a triangle or the like. The holding pegs  42 C protrude towards insides of the bottom part of the shaver head  40 , in a direction of the axis defined by the openings  42 C; preferably, the holding pegs  42 C are not protruding towards outsides of the shaver head  40 , i.e. above the planes defined by the outer border of the lateral walls  42  of the shaver head  40 . The holding pegs  42 C are preferably made of plastic. The holding pegs  42 C may also be made of metal. 
     From the seating wall  46 B protrude a pair of ejection buttons  51 . The ejection buttons are accommodated in corresponding cavities  57 , provided in the bottom part  46  of the shaver head. The buttons  51  (as seen on  FIGS. 6 a  and 6 b   ) are generally cylinder shaped. The end protruding from the seating wall  46 B is preferably closed. The part adjacent the bottom wall  46 A is opened. Inside the ejection buttons  51 , a cavity is formed. The cavity accommodates the coil spring  52 . The coil springs  52  are attached to the bottom wall  46 A. The coil springs  52  provide the ejection buttons  51  with a return force. The part of the ejection buttons  51  which is adjacent the bottom wall  46 A could be provided with a pair of projections  51 A, protruding generally in a direction towards the lateral walls  42  of the shaver head  40 . The projections  51 A help to center the ejection buttons  51  in their position. They also help to prevent accidental twisting of the ejection buttons  51  and the coil springs  52 , thus helping in preventing overload and subsequent damage of the coil spring  52 . The ejection buttons  51  are preferably made of plastic. The coil springs  52  are preferably made of metal. 
     The seating wall  46 B further comprises seating slots  55 . The slots  55  are provided preferably adjacent the ejection buttons  51 . Once the cartridge  60  is inserted into the shaver head  40 , the retention features  65  provided on the cartridge  60  go through the seating slots  55  and are retained by the rotating bar  45 , as will be explained later. 
     The bottom part  46  of the shaver head  40  further comprises back openings  53 . The back openings  53  go through the back wall  43  of the shaver head  40 . 
     Preferably, the ejection buttons  51 , the seating slots  55 , and the back openings  53  are positioned symmetrically with respect to a plane perpendicular to the shaving plane defined by the blades  63 . 
     The bottom part  46  of the shaver head  40  further comprises a slot  54 . Preferably, the slot  54  is positioned between the back openings  53 . Into the slot  54 , the leaf spring  56  is inserted. The leaf spring  56  is inserted only partly, so that the leaf spring  56  protrudes from the slot  54  towards the insides of the shaver head  40 . The leaf spring  56  (seen on  FIGS. 6 a  and 6 b   ) takes a form of a rectangle. The leaf spring  56  is preferably made of metal, but may be also made in any suitable material, such as plastic or material with elastic properties. 
     The bottom part  46  of the shaver head further comprises a rotating bar  45 . In an example of a rotating bar  45  shown on  FIG. 4 b   , the rotating bar  45  takes an overall shape of an elongated cylindrical body. Alternatively, instead of the elongated body being cylindrical, it can also be provided in a form of an elongated body with a cross section being triangular, rectangular, elliptical or the like. 
     At each end of the elongated body, there is a cavity  45 B, adapted to accommodate one of the holding pegs  42 B. The holding pegs  42 B then hold the rotating bar  45  inside the bottom part  46  of the shaver head  40 , and also facilitate rotation of the rotating bar  45 . The axis defined by the holding pegs  42 B then becomes the axis of the rotation of the rotating bar  45 . 
     Preferably in the middle part of the rotating bar  45 , a cavity  45 C is provided. The cavity  45 C takes an overall shape of a wedge, spanning along approximately one fourth to one third of the length of the rotating bar  45 . The vertex of the cavity  45 C cooperates with the leaf spring  56 . When the leaf spring  56  is inserted, it connects the rotating bar  45  and the bottom part  46  of the shaver head  40 . When the rotating bar  45  is rotated from a neutral position, the leaf spring  56  finds itself under tension and thus the leaf spring  56  returns the rotating bar  45  to its neutral position. 
     The rotating bar  45  is provided with at least one projection  45 A. Preferably, there is a pair of projections  45 A. The projections  45 A are preferably located adjacent the cavity  45 C. The projections  45 A have preferably at least one flat surface. The projections  45 A are inserted into the back openings  53  and protrude above a plane defined by the back wall  43 . The back openings  53  are so wide as to enable movements of the projections  45 A, generally in a direction parallel with the direction of shaving. The number of openings  53  thus preferably corresponds to the number of the projections  45 A. 
     The rotating bar  45  further comprises at least one depression  45 D. The number of depressions  45 D preferably corresponds to the number of the ejection buttons  51 . Preferably, there is a pair of depressions  45 D. The depressions  45 D are adapted to accommodate the ejection buttons  51  and the coil springs  52 . The depressions  45 D preferably take such a shape that the ejection buttons  51 , when provided with the projections  51 A, are prevented from turning and twisting. 
     The rotating bar  45  is further provided with at least one retention cavity  45 E. The number of retention cavities corresponds to the number of seating slots  55 . Preferably, there is a pair of retention cavities  45 E. The retention cavities  45 E are positioned so as to be aligned with the seating slots  55 . The parts of the retention cavities  45 E which are positioned adjacent the seating wall  46 B are provided with a retention portion  45 F. The retention portion  45 F may take a part of a small hook compatible with the retention features  65  on the cartridge  60 . 
     The cartridge  60  comprises a bottom wall  67 , which further comprises retention features  65 . In an example shown on  FIGS. 3 a    and  5 , the retention features form a pair of hooks  65 , protruding downwardly from the bottom wall  67 . Generally, the number of hooks  65  correspond to the number of seating slots  55  provided in the seating wall  46 B of the shaver head  40 , and also to the number of retention cavities  45 E, provided on the rotating bar  45 . The hooks  65  from an example from  FIGS. 3 a    and  5  are generally L-shaped, the bent part being oriented towards the shaving plane. Thus, the retention portion  45 F of the retention cavities takes a shape of complementary hooks, the bent part of which is oriented away from the shaving plane. 
     When the cartridge  60  is inserted into the shaver head  40 , the retention features  65  encounter the retention portion  45 F of the rotating bar  45  and are locked by the retention portion  45 F of the rotating bar  45 . In the example shown on the Figures, the small hooks  65  provided on the cartridge are snap-fitted with the small hooks  45 F provided in the retention cavities  45 E of the rotating bar  45 , and the cartridge  60  is thus locked and held in place. At that moment, the rotating bar  45  is in its neutral position. When the cartridge  60  is inserted into the shaver head  40 , the ejection buttons  51  and the underlying coil springs  52  are compressed. 
     Once the cartridge  60  is inserted into the shaver head  40 , the cartridge  60  preferably does not perform any movements with respect to the shaver head  40 . The shaver head  40  is attached pivotally to the handle  20 ; preferably, the pivoting means  22 ,  41  are provided on the shaver head  40  and on the handle  20 , but not on the cartridge  60 . 
     The above described mechanism, which uses the rotating bar  45  provided on the shaver head  40  and the holder  65  provided on the cartridge  60 , brings about several advantages. The only replaced component is the cartridge  60 , which in itself does not hold any additional features (such as pivoting means and the like). Therefore the price of the cartridge  60  may be lowered and the manufacturing process thereof may be simplified; as the shaver head  40  and the handle  20  are not replaced, they may be manufactured as being more robust while keeping the price reasonable. Especially, the means provided to secure the pivoting attachment of the shaver head  40  to the handle  20 , may be made more reliable. The holder  65  of the cartridge is snap-fitted to the complementary feature of the shaver head  40 . This setting both reduces costs and maintains reliability of the attachment of the cartridge  60  to the shaver head  40 . Moreover, as the mechanical parts of the rotating lock  45  are provided not facing the outside, the wear of the mechanical parts is reduced, and the lifetime of the rotating bar may be increased. 
     Since the shaver head  40  and the cartridge  60  are provided with guide tracks  42 A and  62 A, respectively, the insertion of the cartridge  60  into the shaver head  40  is simplified and the risk of wrong insertion of the cartridge  60  is lowered. 
     When the cartridge  60  is attached to the shaver head  40 , the ejection buttons  51  and the coil springs  52  are compressed. Therefore, when the cartridge  60  is disengaged, the ejection buttons  51  and the coil springs  52  urge the cartridge away from the shaver head  40 . 
     The top part of the handle  20  adjacent the shaver head  40  is also provided with a button  30  (see  FIGS. 7 a  and 7 b   ). The button  30  has a front end  30 A and a rear end  30 B. The button  30  is slidable in a direction generally parallel to the longitudinal direction of the handle  20 . To ensure sliding of the button  30 , a pair of guides  37  is provided on the part of the button  30  that is adjacent to the handle  20 . The guides  37  encounter the guide trails  27 B provided on the front portion of the handle  20 ; preferably, the guides  37  are provided with a bent lower portions  37 A so as to ensure that they do not disengage from the guide trails  27 B. In this way, the guides  37 , when in cooperation with guide trails  27 B, provide the button  30  with sliding in a direction generally parallel to the length of the handle  20 , prevents the button  30  from moving elsewhere, and also prevents the button  30  from disengaging from the handle  20 . 
     The button  30  comprises a finger receiving region  32 , provided on the top part of the button  30 . As can be seen on  FIG. 7 a   , the finger receiving region  32  may be equipped with features that help to prevent slipping of user&#39;s fingers. Once the user encounters the button  30  with his/her finger, s/he may push the button  30  in a direction towards the shaver head  40 . To return the button  30  to its initial position, the button  30  is provided with a coil rest  35 , which is positioned at the rear end  30 B of the button  30 , adjacent the handle  20 . The coil rest  35  cooperates with the coil spring  36 . When the button  30  is pressed by the user, the coil spring  36  is compressed, and once the button  30  is released, the coil spring  36  returns the button  30  to its original position. 
     The button  30  further comprises a pusher  31 . The pusher  31  is located in the front end  30 A of the button, adjacent the shaver head  40 . The pusher  31  takes a form of at least one projection which extend from the button  30  in a direction of the shaver head  40 . The number of the projections  31  preferably corresponds to the number of the projections  45 A provided on the rotating bar  45 . Preferably, there is a pair of projections  31 . The projections  31  provided on the button  30  are preferably aligned with the projections  45 A provided on the rotating bar  45 . 
     Once the user wishes to replace the cartridge  60 , s/he pushes the button  30  and the cartridge  60  is disengaged. More specifically, the projections of the pusher  31  encounter the projections  45 A of the rotating bar  45 . The projections  45 A are moved upwards, in a direction towards the top wall  61  of the cartridge  60 . The rotating bar  45  is thus rotated. Once the rotating bar  45  is rotated, the retention features  65  provided on the cartridge  60  are released from the retention cavities  45 E, provided on the rotating bar  45 . In the example shown on the Figures, when the rotating bar  45  is rotated, the hooks that form the retention features  65  are released from the hooks forming the retention portion  45 F. When the retention features  65  are disengaged from the retention cavities  45 E, the cartridge  60  is urged away from the shaver head  40  by the ejection buttons  51 . The ejection buttons  51  are operated by the coil springs  51 , which are compressed, when the cartridge  60  is inserted, and which urge the cartridge  60  away once it is disengaged. The axis of rotation for the rotating bar  45  is defined by the holding pegs  42 B. The rotating bar  45  is then returned to its neutral position by the leaf spring  56 . 
     In this way, the user does not have to touch the cartridge  60  by his/her fingers and the risk of cutting the user&#39;s fingers with the blades  63  is then reduced.