Patent Document

CROSS-REFERENCE. TO RELATED APPLICATIONS 
       [0001]    This application is a division of U.S. patent application Ser. No. 12/289,801 filed on Nov. 4, 2008 which is a continuation of U.S. patent application Ser. No. 11/430,280 filed on May, 9, 2006 (U.S. Pat. No. 7,448,107) which is a continuation of U.S. patent application Ser. No. 10/697,206 filed on Oct. 30, 2003 which is a continuation of U.S. patent application Ser. No. 10/456,769 filed on Jun. 6, 2003 (U.S. Pat. No. 6,760,946) which is a continuation of U.S. patent application Ser. No. 09/425,423 filed on Oct. 22, 1999 (U.S. Pat. No. 6,574,820). 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to the field of oral care, and in particular to toothbrushes. More specifically, the invention relates to a brush head for a toothbrush. 
       BACKGROUND OF THE INVENTION 
       [0003]    U.S. Pat. No. 5,577,285 (the &#39;285 patent) discloses an electric toothbrush with a rotary bristle supporting structure. In one embodiment of the invention shown in  FIG. 6 , the brush head is driven such that an outer ring of bristles  45   a  and an inner ring of bristles  45   b  are moved in an alternating rotary motion in opposite directions. While such an arrangement is beneficial for cleaning, for example, the bucal or lingual tooth surfaces, the lack of motion of any of the bristles in an up and down pattern results in a less than optimal cleaning of the inter-dental tooth surfaces. 
         [0004]      FIG. 9  of the &#39;285 patent discloses an additional embodiment of the invention in which all of the bristles  45  are rotated about an axis  54  while also being moved in an up and down motion parallel to this axis. This embodiment will provide enhanced cleaning of the inter-dental tooth surfaces. However, the fact that all of the bristles are moved up and down limits the depth of penetration that the bristles can obtain between the teeth. This is because while some of the bristles are trying to penetrate between the teeth, others are pressing against, for example, the bucal tooth surface, thus limiting the motion of the brush head towards the teeth. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, a head for an electric toothbrush, includes a first bristle support which is rotatable about an axis and a plurality of first bristles extending from the first bristle support. A second bristle support includes a plurality of second bristles extending from a surface of the second bristle support at an acute angle to the surface. 
         [0006]    These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a side view of an electric toothbrush head attached to a brush handle/drive; 
           [0008]      FIG. 2  is an exploded side view of the toothbrush head; 
           [0009]      FIG. 3A  is a side view of the head with a central bristle in a retracted position; 
           [0010]      FIG. 3B  is a side view of the head with a central bristle in an extended position; 
           [0011]      FIG. 4  is a top plan view of a second embodiment of an electric toothbrush head; 
           [0012]      FIG. 5  is a sectional view of  FIG. 4  taken along the lines  5 - 5 ; 
           [0013]      FIG. 6  is a sectional view of  FIG. 5  taken along the lines  6 - 6 ; 
           [0014]      FIG. 7  is a sectional view of  FIG. 5  taken along the lines  7 - 7 ; 
           [0015]      FIG. 8  is a sectional view similar to  FIG. 5  of a third embodiment of the invention; 
           [0016]      FIG. 9  is a sectional view of  FIG. 8  taken along the lines  9 - 9 ; 
           [0017]      FIG. 10  is a sectional view of  FIG. 8  taken along the lines  10 - 10 ; 
           [0018]      FIG. 11  is a sectional view of  FIG. 8  taken along the lines  11 - 11 ; 
           [0019]      FIG. 12  is a sectional view of  FIG. 8  taken along the lines  12 - 12 ; 
           [0020]      FIG. 13  is a perspective view of a fourth embodiment of a toothbrush head; and 
           [0021]      FIG. 14  is a front view of the toothbrush head of  FIG. 13 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Beginning with  FIG. 1 , an electric toothbrush head  10  includes a neck  12  which is connected to a bristle support  14 . Bristles  16  on support  14  are oscillated in a rotary movement through an arc of between about +−15 to 90 degrees, more preferably +−20 to 50 degrees as in a conventional electric toothbrush. 
         [0023]      FIG. 2  shows support  14  in an exploded side view. An interdental probe  18  is secured to a slider core  20  in the center of bristles  16 . Probe  18  can be a single large bristle or a tuft of much smaller bristles. Alternatively, core  20  can be enlarged to accommodate a plurality of probes (not shown), one of which may be positioned in the center of the core (as in  FIG. 1 ), with the remainder of the probes being positioned on the core away from its center. 
         [0024]    A pair of cam follower pins  22  are secured to opposite sides of the lower portion of core  20 . Core  20  is positioned inside of a brush base  24  such that pins  22  are forced to ride along respective cam tracks  26  as well as respective vertical slider tracks  28  (one slider track is hidden behind the other). A retaining pin  30  rides in a track  32  to retain base  24  within a housing  34 . A guide/rotation pin  36  passes through a hole in the bottom of housing  34  and is secured to base  24 . 
         [0025]    Operation of support  14  will be explained with reference to  FIGS. 2 ,  3 A and  3 B. Pin  36  is oscillated about its long axis by a drive mechanism (not shown) in neck  12 . The drive mechanism can be of conventional design. Oscillation of pin  36  causes brush base  24  and bristles  16  to oscillate in a rotary pattern. Pin  30  retains base  24  within housing  34 . Oscillation of base  24  causes core  20  and probe  18  to oscillate with the base because pins  22  ride in track  28  of the base. Pins  22  also ride in respective tracks  26  in the housing, thus causing core  20  and probe  18  to move up and down relative to bristles  16  during oscillation of brush base  24 .  FIGS. 3A and 3B  show that a preferred extension of probe  18  from its lowest to highest position is about 5 mm. 
         [0026]    In an alternative embodiment, all of bristles  16  are eliminated, leaving only probe  18  for cleaning teeth. This embodiment would be used primarily for cleaning interdental spaces, not for cleaning the other surfaces of teeth. 
         [0027]    Turning to  FIGS. 4-7 , a second embodiment of the invention will be described. A brushead  40  can be attached to a handpiece (not shown) of an electric toothbrush. A driveshaft (not shown) protrudes out of the handpiece and can effect an oscillating rotation. Brushhead  40  includes a tube  42  in which a shaft  44  is located. The rear end of tube  42  fits into the housing (not shown) of the handpiece. Shaft  44  engages the driveshaft of the handpiece. A pin  46  is press fitted into shaft  44 . Pin  46  can rotate at its free end in a bearing hole  48  in a front part  50  of tube  42 . Axis  52  of pin  46  coincides with the axis of the driveshaft of the handpiece. 
         [0028]    A pivot  54  can rotate in a bearing hole  56  situated in front part  50  of tube  42 . Pivot  54  is retained in hole  56  by a ring  58 . A brush base  60  is press fitted onto pivot  54 . Brush base  60  has holes  62  in which tufts of bristles  64  are secured. A cross pin  66  is welded onto the free end of pivot  54 . Both ends of cross pin  66  retain brush base  60  on pivot  54  by interaction with a shoulder  68  of the brush base. The central part of cross pin  66  is placed in a bearing hole  70  of a rocker  72 . Rocker  72  can swivel about cross pin  66  and contains holes  74  in which tufts of bristles  76  are secured. 
         [0029]    Shaft  44  includes a bearing hole  78  in which a drive rod  80  can move. The distance between axis  52  of pin  46  and an axis  82  of drive rod  80  is a radius r 1 . A stud  84  is welded onto the free end of drive rod  80 . The distance between an axis  86  of pivot  54  and an axis  88  of stud  84  is a radius r 2 . Stud  84  can move in a bearing seat  90  in brush base  60 . At one end of stud  84  is carried a ball  92  which can move in a cylindrical slot  94  in rocker  72 . 
         [0030]    When shaft  44  is oscillated about axis  52  through an angle of +−alpha  1  about pin  46 , two different motions are induced. First, brush base  60  and rocker  72  are oscillated in a rotating manner through an angle of +−beta  1  about pivot  54  in bearing hole  56 . This oscillating rotation causes bristles  64  to wipe plaque off teeth like a broom. Second, rocker  72  is oscillated in a rotating manner through an angle of +−gamma  1  about cross pin  66  in bearing hole  70 . Oscillation of rocker  72  about pin  66  causes bristle tufts  76  to loosen plaque like a chisel. Two cycles of oscillation of rocker  72  about pin  66  occur for every one cycle of oscillation of base  60  and rocker  72  about pivot  54 . The relations between the oscillation angles alpha  1  to beta  1  and alpha  1  to gamma  1  depend only on radii r 1  and r 2 . 
         [0031]    Referring to  FIGS. 8-12 , a third embodiment of the invention will be described. The third embodiment modifies the relationship between the oscillation angles, primarily to increase the gamma angle of the oscillating rotation of rocker  72 . The basic features of the third embodiment remain unchanged from the second embodiment. The main difference is in the location of the drive rod. 
         [0032]    In the mid-position of the oscillating rotation of a shaft  100 , a drive rod  102  is located at a distance e from a median plane  104  of a brushhead  106 . A stud  108  is welded laterally on a free end of drive rod  102  with a distance e between the center-lines. Stud  108  is movable in a bearing seal  110  of a brush base  112 . When a drive shaft  114  is in a mid-oscillation position, stud  108  is in a median plane  116  of brush base  112 . Drive rod  102  can move in a bearing hole  118  in shaft  114 . Bearing hole  118  is situated in the distance e from median plane  104  of shaft  114  when the shaft is in its mid-oscillation position. 
         [0033]    When shaft  114  is oscillated about median plane  104  through an angle of +−alpha  1 , two different motions are induced. First, brush base  112  and rocker  72  are oscillated in a rotating manner through an angle of +−beta  2  which is smaller than +−beta  1  about axis  120 . Second, rocker  72  is oscillated in a rotating manner through an angle of +−gamma  2  which is bigger than +−gamma  1  about cross pin  66 . The relations between the oscillation angles alpha  1  to beta  2  and alpha  1  to gamma  2  depend on radii r 1  and r 2  as well as on the distance e. 
         [0034]    In embodiments 2 and 3 of the invention, one component of the rocking motion of rocker  72  causes bristles  76  to move up and down (i.e. substantially parallel to pivot  54 ) relative to bristles  64 . 
         [0035]      FIGS. 13 and 14  disclose a toothbrush head  130  which is similar in function to the head of  FIG. 4 . The major difference is that tufts of bristles  132  on a pivot bar  138  are tilted away from the perpendicular (to the top surface  140  of the pivot bar  138 ) at an angle  134  of between about 1-20 degrees. Preferably the bristles  132  are tilted along the direction of oscillation of bristles  136  on a brush base  142 . Such tilting of bristles  132  provides better interdental penetration during the respective upstrokes of pivot bar  138 , particularly for the tuft(s) on bar  138  which are being moved by head  130  in the tilt direction. It is preferable that tufts of bristles on both sides of bar  138  have the same tilt angle and are tilted in the same direction (i.e. in the same plane). Alternatively, tufts of bristles on opposite sides of the bar can be tilted in opposite directions. As shown in  FIGS. 13 and 14 , when pivot bar  138  is oscillated relative to brush base  142 , the top surface  140  of pivot bar  138  and the top surface  144  of brush base  142  are capable of lying in substantially a same plane (when pivot bar  138  is aligned with brush base  142 ) during the operation of the electric toothbrush. 
         [0036]    The invention has been described with reference to several embodiments including a preferred embodiment. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention.

Technology Category: 1