Abstract:
A vibratory appliance includes a tool driven to oscillate by a rotary electric motor. A mechanism for converting rotary movement to oscillatory movement includes magnetic couplers moveable relative to one another. A displacement mechanism moves one of the magnetic couplers relative to the other magnetic coupler and varies the amplitude of oscillation of the tool.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to hand-held motorised vibratory appliances in which the amplitude of movement of an oscillatory tool is adjustable. 
       BACKGROUND OF THE INVENTION 
       [0002]    An increasingly large range of types of hand-held electrical appliances are in use. These small appliances may include, for instance, personal care devices used for cleaning, grooming, physical stimulation, skin, hair or oral care, such as brushes, trimmers, razors, and the like, as well as other types of appliances for home or commercial use. In the use of personal care appliances a tool, such as a brush, a massage tool, applicator pad, blade, or the like, is motor-driven to oscillate. While users may readily select an appliance among different models according to a preference for the frequency of tool oscillation, the provision for a variable amplitude of oscillation to suit is less common. Advantageously, it is possible to provide a mild or intense action according to the amplitude of tool movement. Varying the amplitude of tool movement can be achieved in appliances having electromagnetic drives through the use of circuits that control the driving magnetic fields. However these types of control systems are relatively costly, and a need exists for a more inexpensive vibratory appliance which enables the amount of tool movement to be varied according to user preference. 
         [0003]    As well as providing varying amounts of tool movement, it is known to employ a vibration exciter in an electric vibratory appliance to drive oscillation of the tool in different modes. For instance the oscillation may be rectilinear, rotational, orbital or a combination of these movements in different axes. Accordingly, a solution which enables the amount of tool movement to be varied should be able to accommodate different modes of tool movement, as well as providing a product which can be manufactured at relatively low cost. It is an object of the present invention to address the above needs, or more generally to provide an improved vibratory appliance. 
       DISCLOSURE OF THE INVENTION 
       [0004]    According to one aspect of the present invention there is provided a vibratory appliance comprising: 
         [0005]    a tool mounted for movement relative to a housing; 
         [0006]    an electric motor in the housing; 
         [0007]    a driven member rotated about a drive axis by the electric motor; 
         [0008]    a transmission for transmitting oscillatory movement to the tool; 
         [0009]    a magnetic drive mechanism for converting rotation of the driven member to oscillation of the transmission, the magnetic drive mechanism including driving and driven magnet units each fixed to a respective one of the driven member and the transmission, a gap between the driving and driven magnet units, whereby, rotation of the drive magnet unit causes the drive magnet unit to act upon the driven magnet unit in order to cause oscillation of the transmission, and 
         [0010]    displacement means for moving one of the driving and driven magnet units relative to the other to thereby vary the amount of oscillation of the tool. 
         [0011]    Preferably the tool is a tool, most preferably a tooth tool. Optionally the tool may be a massage tool, an applicator pad, a trimmer or another personal care tool. Preferably the tool is resiliently mounted for movement relative to the housing. 
         [0012]    Preferably the transmission comprises a shaft mounted in the housing to reciprocate longitudinally, the shaft having an intermediate portion between opposing inner and outer ends with journal means engaging the intermediate portion, the inner end of the shaft connected to the driven magnet unit and the outer end of the shaft connected to the tool such that linear reciprocation of the shaft oscillates the tool. 
         [0013]    Preferably the driving magnet unit has a magnetic axis separating the poles, the axis being aligned substantially transverse to the drive axis. 
         [0014]    Preferably the motor has an axis of rotation parallel to the longitudinal axis, the driven member comprises an output shaft of the motor, the driving magnet unit is fixed to rotate with the output shaft, the driven magnet unit is fixed to the inner end of the shaft, and the displacement means displaces the motor and driving magnet unit together substantially parallel to the first axis. Alternatively the driven member may be indirectly coupled to the motor shaft, as by one or more speed-change gear sets. 
         [0015]    Preferably the housing has a longitudinal axis, and a resilient neck mounting the tool to the housing. 
         [0016]    Preferably the housing further comprises guides aligned with the longitudinal axis and engaged with the motor for guiding longitudinal movement of the motor. Detents may be provided for holding one of the first and second couplers in the first and second relative positions. 
         [0017]    Preferably the housing further comprises guides aligned with the longitudinal axis and engaged with the motor for guiding longitudinal movement of the motor. 
         [0018]    Preferably the displacement means is user-controlled, as by operating one or more buttons, switches, grips, knobs or the like for moving the one of the first and second couplers relative to the other, either directly, by an intervening mechanism for example. Alternatively, the displacement means may be driven by an actuator controlled automatically in response, for instance, to a control, or to a current or voltage feedback. 
         [0019]    User-operated displacement means may comprise a rotary operator having a knob by which it may be grasped by the user. For instance, the rotary operator may be mounted to turn in a transverse opening in the housing, a nub on the rotary operator offset from the transverse opening may be received in a substantially transverse channel, such that turning the rotary operator displaces the one of the first and second couplers relative to the other. Alternatively, the rotary operator may be connected to the housing by a screw thread having an axis parallel to the longitudinal axis, such that turning the rotary operator displaces the one of the first and second couplers relative to the other. 
         [0020]    According to another aspect of the present invention there is provided a vibratory appliance comprising: 
         [0021]    a housing having a handle portion; 
         [0022]    a tool mounted for movement relative to the housing; 
         [0023]    an electric motor in the housing; 
         [0024]    a driven member rotated about a drive axis by the electric motor; 
         [0025]    a transmission for transmitting oscillatory movement to the tool; 
         [0026]    a driving magnet unit fixed to a the driven member; 
         [0027]    a rocker pivotally mounted in the housing and operatively connected to the transmission; 
         [0028]    at least one driven magnet unit mounted eccentrically to the rocker, and 
         [0029]    a gap between the driving and driven magnet units, whereby, rotation of the drive magnet unit causes the drive magnet unit to act upon the driven magnet unit in order to cause oscillation of the rocker and the transmission, and 
         [0030]    displacement means for moving one of the driving and driven magnet units relative to the other to thereby vary the amount of oscillation of the tool. 
         [0031]    If one of the driving and driven magnet units comprises an electro-magnet, or permanent magnet, the other of the driving and driven magnet units may comprise an electro-magnet, a permanent magnet or a ferromagnetic material. If both driving and driven magnet units are permanent magnets or electromagnets the other of the driven magnet unit is alternately attracted and repelled. However, if one of the driving and driven magnet units is a permanent magnet or electromagnet, and the other of the driven magnet unit is a ferromagnetic material then the driven magnet unit may be periodically alternately attracted or repelled, against the action of a resilient member. 
         [0032]    Preferably the transmission comprises a longitudinally extending shaft having an intermediate portion between opposing inner and outer ends, journal means engaging the intermediate portion to support the shaft for rotation, the inner end of the shaft connected to rocker to define a driven axis about which the rocker oscillates, and the outer end of the shaft connected to the tool such that turning the shaft twists the tool. 
         [0033]    Preferably the motor has an axis of rotation defining a drive axis offset from or inclined to the driven axis, the driven member comprises an output shaft of the motor and the driving magnet unit is fixed to rotate with the output shaft. 
         [0034]    Preferably the motor has an axis of rotation parallel to the longitudinal axis, the driven member comprises an output shaft of the motor, the driving magnet unit is fixed to rotate with the output shaft, the driven magnet unit is fixed to the inner end of the shaft, and the displacement means displaces the motor and driving magnet unit together substantially parallel to the first axis. Alternatively the driven member may be indirectly coupled to the motor shaft, as by one or more speed-change gear sets. 
         [0035]    Preferably the displacement means for moving one of the driving and driven magnet units relative to the other may be like the displacement means for moving the one of the first and second couplers relative to the other, as discussed above. 
         [0036]    The transmission may comprise a shaft mounted in the housing to reciprocate longitudinally, the shaft having an intermediate portion between opposing inner and outer ends with resilient means engaging the intermediate portion for urging the shaft to a first position, the inner end of the shaft connected to the driven magnet unit and the outer end of the shaft connected to the tool such that linear reciprocation of the shaft oscillates the tool. 
         [0037]    Alternatively the transmission may comprise a shaft mounted in the housing to pivot transverse to its longitudinal axis, the shaft having an intermediate portion between opposing inner and outer ends, with resilient means engaging the intermediate portion for urging the shaft to a first position, the inner end of the shaft connected to the driven magnet unit and the outer end of the shaft connected to the tool such that pivoting reciprocation of the shaft oscillates the tool. 
         [0038]    The transmission may further comprise a rocker to which the driven magnet unit is mounted, the inner end of the shaft being connected to the rocker such that the pivoting reciprocation of the inner end of the shaft follows an arcuate path. 
         [0039]    It will be understood that the above-mentioned aspects of the vibratory appliance of the present invention are encompassed by a vibratory appliance comprising: 
         [0040]    a housing having a handle portion; 
         [0041]    a tool mounted for movement relative to the housing; 
         [0042]    an electric motor in the housing; 
         [0043]    a driven member rotated about a drive axis by the electric motor; 
         [0044]    a transmission for transmitting oscillatory movement to the tool; 
         [0045]    a mechanism for converting rotation of the driven member to oscillation of the transmission, the mechanism including first and second couplers each connected to a respective one of the driven member and the transmission means, and 
         [0046]    displacement means for moving one of the first and second couplers relative to the other to thereby vary the amount of oscillation of the tool. 
         [0047]    This invention provides a vibratory appliance which is effective and efficient in operational use, which has provision for varying the amount of brushing movement completed in each cycle of oscillation according to user requirements or preferences. New users can start use with a low setting, with a relatively low amount of movement, allowing them to be gently introduced to vibratory appliance use with a minimum of discomfort. Moreover, the vibratory appliance has an overall simple design which minimizes manufacturing costs and maximizes performance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0048]    Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: 
           [0049]      FIG. 1  is a schematic longitudinal section through a vibratory appliance according to a first embodiment of the invention; 
           [0050]      FIG. 2  is an exploded pictorial view of the vibratory appliance of  FIG. 1  showing the brush in longitudinal section; 
           [0051]      FIG. 3  is a fragmentary longitudinal section through the drive mechanism of  FIG. 1 ; 
           [0052]      FIG. 4  is an end view of the magnet units of the vibratory appliance of  FIG. 1 ; 
           [0053]      FIG. 5  is a schematic exploded isometric view of a vibratory appliance according to a second embodiment of the invention, an which some internal components are shown in longitudinal section, and 
           [0054]      FIG. 6  is a schematic end view of the rocker of the vibratory appliance of  FIG. 5 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0055]    Referring to  FIGS. 1-4 , a first embodiment of a vibratory appliance according to the invention may comprise a housing  10 , which may comprise a pair of elongate shells  11 ,  12  joined generally at a longitudinal plane. The housing  10  provides a handle portion by which the apparatus is held and encloses a rotary motor  13 , and may also hold batteries  140  for powering the motor. The motor  13  has a rotating output shaft  14  aligned with a longitudinal axis  15 . Guides are provided for allowing the motor to move longitudinally within the housing  10 , and may comprise tongues  16  on opposing sides of a mount  160  to which the motor  13  is fixed. Each tongue  16  is slidingly received in a complementary groove (not shown) in the inner side of the shells  11  and  12 . The tolerances are such that there is very little transverse play in this tongue and groove coupling. A cap  17  and a tool, such as a brush  18  are mounted to the longitudinally opposing ends of the housing  10 . 
         [0056]    The brush  18  may be a replaceable member having bristles  19  fixed in a bristle block  20  at its outer end. An elongate stem  130  connects the bristle block  20  to a resilient portion  21  disposed at the inner end of the brush  18 . The resilient portion  21  may be integral with the bristle block  20  and stem  130  as shown. The resilient portion  21  may be formed with a plurality of circumferential ribs, such as ribs  31  axially adjacent one another. The brush  18  is thus flexibly mounted by the resilient portion  21 , thereby allowing the bristle block  20  to move relative to the housing  10 . A longitudinal cavity  22  in the brush  18  extends through the resilient portion  21  and has an open mouth at the inner end of the brush and a blind end  23  of a partly spherical form. 
         [0057]    A shaft  24  is elongated longitudinally and has an intermediate portion  25  between opposing inner and outer ends  26  and  27  respectively. A bush  128  held in a neck  30  of the housing  10  extends about the intermediate portion  25  and provides a journal which supports the shaft  24  for generally longitudinal sliding movement. The outer end  27  of the shaft extends into the cavity  22  and may have a ball formed thereon, complementary in form to the blind end  23  in which it is engaged. The inner end  26  is connected to a magnetic drive mechanism  231 , such that the shaft  24  and bush  128  provide a transmission for transmitting oscillatory movement to the brush  18 . 
         [0058]    The magnetic drive mechanism  231  comprises a magnetic coupling between driving and driven couplers, or magnet units  60  and  61  in a magnetic circuit. By the use of displacement means to move one of the coupling magnet units relative to the other the amount of oscillation of the brush during rotation of the motor may be varied. 
         [0059]    The magnet units  60 ,  61  may be of like construction, each comprising a permanent magnet having a magnetic axis  62  separating their opposing magnetic poles N, S, the axis  62  being aligned substantially transverse to the axis  15 . The magnet units may have a cylindrical form, with their axes parallel to the axis  15 . In this manner rotation of the drive magnet unit  60  mounted to the motor shaft  14  causes the drive magnet unit  60  to alternately attract and repel the driven magnet unit  61 . The driven magnet unit  61  is resiliently mounted to the housing  10 , by virtue of the connection between the shaft  24  and the brush  18 . A gap  63  is provided between the driving and driven magnet units  60 ,  61 . Accordingly, as the driven magnet unit  61  is attracted and repelled it is displaced longitudinally relative to the drive magnet unit  60 . The ball on the shaft end  27  may be received in the blind end  23  in a manner such that shaft  24  is able to both longitudinally extend and compress the resilient portion  21  during oscillation of the brush. Cooperating guide means  64  on the housing  10  and driven magnet unit  61  may be provided to restrain the movement of the driven magnet unit  61  to linear movement in the longitudinal direction. 
         [0060]    Displacement means are provided, and may move the motor  13  and attached magnet unit  60  to thereby vary the amount of oscillation of the brush  18 . Exemplary displacement means shown in  FIGS. 1-3  comprise a rotary operator  40  having a knob  41  by which it may be grasped by the user. The rotary operator  40  is mounted to turn in a transverse opening  42  in the housing  10 . An eccentric nub  43  on the rotary operator  40  is offset from the axis of the transverse opening  42 . The nub  43  is received in a substantially transverse channel  44  in the motor mount  160  to which the motor  13  is fixed, such that turning the rotary operator  40  displaces the motor  13 , and attached magnet unit  60  longitudinally. In use, the operator may rotate the rotary operator  40  to select a desired amount of brush movement. The rotary operator  40  is grasped by the user and turned to displace the motor  13 , motor shaft  14  and driving magnet  60  longitudinally for varying the amount of displacement of the bristles  19  in the longitudinal direction. Friction, or other detent means, may hold the rotary operator  40  in any user-selected angular position. 
         [0061]    Referring to  FIG. 5 , a second embodiment of a toothbrush according to the invention incorporates a magnetic drive mechanism  331  which, like the magnetic drive mechanism  231 , includes a driving magnet unit  60  mounted to rotate with the motor output shaft  14  (shown in longitudinal section) about the driving axis  15   a.    
         [0062]    Mounted on a rocker  70  are driven magnet units  61   a ,  61   b  disposed on opposing transverse sides of the driving axis  15   a , with a gap therebetween into which the driving magnet unit  60  may extend. Like poles of the respective magnet units  61   a ,  61   b  are disposed adjacent the driving magnet unit  60 . The magnetic axes  162  of the driven magnet units  61   a ,  61   b  may be parallel and/or coaxial (i.e. aligned with the geometric axis of their cylindrical forms) to one another. The coaxial magnetic axes  162  may be aligned substantially transverse to the driving axis  15   a.  The rocker  70  comprises a pair of opposing flanges  71 ,  72  joined by a web  73  to form a channel shape, with the driven magnet units  61   a ,  61   b  mounted inside the flanges  71 ,  72 . A boss  74  may be provided integral with the web  73 . An aperture  75  in the boss  74  defines a driven axis  15   b  generally parallel to the driving axis  15   a , from which it is offset by dimension  76 . The driven magnet units  61   a ,  61   b  are mounted eccentrically relative to the driving axis  15   a  of the rocker  70 , such that torque is applied to the rocker by interaction between the magnet units. 
         [0063]    The brush  118  has like construction as the first brush  18 , except that a formation  123  is provided in the blind end. Complementary features (not shown) are provided on the inner end  79  of the brush and the neck  30  to prevent relative rotation between the neck  30  and the inner end  79  when the brush is mounted to the housing. The resilient portion  21  may be torsionally resilient, allowing the bristles  19  to rock about driven axis  15   b  between angular positions disposed either side of a central, neutral position, while there is no oscillation of the inner end  79 . 
         [0064]    On the outer end of the shaft  124  a formation  77  is provided, comprising one or more flats disposed about the periphery of the shaft, complementary to the formation  123  in the blind. The connection between these complementary formations allows torque to be transmitted between the shaft  124  and the brush  18 , while providing a demountable connection for mounting the brush  118 . The opposing inner end of the shaft  124  is fixed in the recess  75  in the rocker  70 . The shaft  124  is journalled for rotation about the axis  15   b  in the bush  128 , which is held in the neck portion of the housing  10 . The shaft  124  may be a solid bar or, for greater torsional stiffness, a hollow bar. The shaft  124  is thus rotationally fast with the rocker  70 , and serves to support the rocker  70  for oscillation within the housing  10  between two angular positions, while it is biased to the central position shown by the action of the resilient portion  21 . 
         [0065]    As shown in  FIG. 6 , a resilient bumper  80  may be provided on either side of the rocker  70  to abut the rocker and thus limit its angular movement, as to angle  82  either side of the neutral position shown. 
         [0066]    In this manner, the motor  13  rotates the driving magnet unit  60 , impelling the rocker  70  to oscillate about the longitudinal driven axis  15   b,  periodically reversing the torsion applied to the shaft  124  and to the brush  118 . The bristles  19  are thus turned from side to side as the brush  18  is driven to twist. The rotary operator  40  may be grasped by the user and turned in the manner described above, to displace the motor  13  and driving magnet unit  60  longitudinally. As the driving magnet unit  60  is brought closer to the driven magnet units  61   a ,  61   b  larger impulses are transmitted through the shaft  124  to the brush, for varying the amount of displacement of the bristles  19  in operation. 
         [0067]    Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.