Abstract:
A toothbrush is disclosed. The toothbrush includes a head; a base member supported by a neck; a support member having a plurality of holes therein; a resilient cushion member disposed, at least in part, between the base member and the support member, the cushion member being fixed to the support member; at least one center bristle tuft extending from the support member; and two or more outer bristle tufts located at least partially around the at least one center bristle tuft. The center bristle tuft has a first shaped cross section and the outer bristle tufts have a second shaped cross section. The first shaped cross section is different from the second shaped cross section. Applying a force to the center bristle tuft and/or the outer bristle tufts causes the center bristle tuft and/or the outer bristle tufts to deflect into the resilient cushion member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of application Ser. No. 12/008,774, filed Jan. 4, 2008, which is a continuation of application Ser. No. 11/513,632 filed on Aug. 31, 2006 which is a continuation of application Ser. No. 09/824,310 filed on Apr. 2, 2001, each of which is incorporated herein by reference in its entirety herein. 
     
    
     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 electric toothbrushes. 
       BACKGROUND OF THE INVENTION 
       [0003]    Electric toothbrushes are well known and have been on the market for years. With typical electric brushes all of the tufts of bristles on the brush head are vertically oriented relative to the top surface of the head. The tufts are oscillated, rotated and/or translated in order to provide enhanced tooth cleaning capability. 
         [0004]    German Gebrauchsmuster 8807968.6 discloses a head for an electric toothbrush. A first group of circular tufts  18  are arrayed in a first ring about the center of rotation of the head. A second group of taller circular tufts  16  are arrayed in a second ring which is outside the first ring and also encircles the center of rotation of the head. All of tufts  16  and  18  are circular in cross-section and are canted away from the center of the head at an acute angle relative to a top surface of the head 
         [0005]    A problem with this brush is that all of the tufts have a circular cross-section. Such tufts are not that effective at penetrating between teeth to clean the interdental or approximal areas of the teeth. Further, all but one of the tufts are angled away from the center. Such a tuft pattern tends to flair (flatten) out even more than designed during use, thereby having the same brushing characteristics as a worn-out standard brush. Additionally, none of the tufts are angled along the direction of the rotational circumference which results in even poorer interdental penetration of the bristles. 
         [0006]    European Patent 0765642 also discloses a head for an electric toothbrush. There are a number of bristle tufts  17  which are vertically oriented on the head. Bristle tufts  13 ,  15  are located about a perimeter of the circular head and are tilted at an acute angle along a circumference of a top surface of the head. All of the tufts on the head have a circular cross-section. 
         [0007]    Again we see the problem of a brush head in which all of the tufts have a circular-cross-section: such tufts do not penetrate well in the approximal tooth areas. This head also has no tufts which are angled away from the center to sweep along the gum line or gingival margin of the mouth. Further, in two pairs of the tufts  13 , the tufts are adjacent to each other and are angled towards each other. These two tufts appear to be in contact. A downside to this tuft arrangement is that the two adjacent tufts can tend to interfere with each other during use of the brush. In addition, due to the tuft configuration and shape, a lot of the available space of the head is not used. This reduces efficacy and increases wear of the head (flare) upon use. For effective brushing approximately 32-36% of the head surface must be covered with tufts/bristles. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention may overcome 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 support member and a plurality of tufts of bristles supported at their base by the support member. Two of the tufts have their bases adjacent to each other and are tilted away from each other at an acute angle relative to the support member. 
         [0009]    According to a second aspect of the invention, a head for an electric toothbrush includes a support member having a plurality of holes extending completely therethrough. A plurality of tufts of bristles each extends through one of the holes. A first brushing end of each tuft projects from a first side of the support member. Each tuft is prevented from being withdrawn from its hole when a tensile force is applied to the first end of each tuft along a long axis of the tuft. A resilient cushion is positioned adjacent a second side of the support member such that a second end of each tuft can contact the cushion. When a compressive force is applied to the first end of each tuft along the long axis of each tuft, each tuft can move in its hole in a first direction into the cushion. When the compressive force is removed the cushion causes each tuft to move in its hole in a second direction substantially opposite the first direction. 
         [0010]    According to a third aspect of the invention, a head for an electric toothbrush includes a support member and a plurality of tufts of bristles supported at their base by the support member. The support member has a substantially circular surface from which the tufts project. A first one of the tufts is tilted along an imaginary radius which projects from a center of the circular surface and passes through a base of the first tuft. A second one of the tufts is tilted along an imaginary circumference which encircles the center of the circular surface and passes through a base of the second tuft. 
         [0011]    According to a fourth aspect of the invention, a head for an electric toothbrush includes a support member and a plurality of tufts of bristles supported at their base by the support member A pair of the tufts is tilted in substantially the same direction relative to the support member. A first tuft of the pair has a different cross-section than a second tuft of the pair. 
         [0012]    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 
         [0013]      FIG. 1  is a side view of a portion of an electric toothbrush; 
           [0014]      FIG. 2  is a is an exploded view of  FIG. 1 ; 
           [0015]      FIG. 3  is a front view of  FIG. 1  looking along the direction of arrow  3 ; 
           [0016]      FIG. 4  is a side view of a cushion, support member and tuft of bristles of the toothbrush of  FIG. 1 ; 
           [0017]      FIG. 5  is a perspective view of a second embodiment of a head for an electric toothbrush; 
           [0018]      FIG. 6  is an enlarged top view of the head of  FIG. 5 ; 
           [0019]      FIG. 7  is a sectional view of  FIG. 6  taken along lines A-A; 
           [0020]      FIG. 8  is a sectional view of  FIG. 6  taken along lines B-B; and 
           [0021]      FIG. 9  is a sectional view of  FIG. 6  taken along lines D-D. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiment 1 
       [0022]    Beginning with  FIGS. 1 and 3 , an electric toothbrush  10  includes a neck  12  and a head  14 . 
         [0023]    As is well known to those skilled in the art, head  14  is oscillated through an angle of preferably +20 to 50 degrees about an axis parallel to an arrow  3 . Electrical power is preferably supplied by rechargeable or single use batteries. The batteries power an electric motor which, through gearing or another linking element, oscillates the head. Further details as to how the head is oscillated will not be provided as this aspect of the brush is not the focus of the invention. 
         [0024]    Head  14  contains a large number of tufts of varying lengths, cross-sections and orientations. Although each tuft is shown as a solid mass in the drawings, the tufts are actually each made up of a great mass of individual plastic bristles. The bristles are preferably made of 612 nylon. Each of tufts  16  are oval in cross-section with a 6.1 mm height. The dimensions of the oval are 1.78 mm×3.05 mm. 5 or 6 mil filament can be used for tuft  16 . The tuft is vertically oriented relative to the top surface of the head. 
         [0025]    Each of tufts  18  are triangular in cross-section with rounded vertexes (tri-oval in shape). These tufts are 6.35 mm in height with a dimension of 2.03 mm from the rounded vertex nearest the center of the head to its opposite side. Tufts  18  also have a dimension of 2.28 mm between the two remaining rounded vertices. Preferably 6 mil filament is used to make the bristles for this tuft. The tuft is vertically oriented relative to the top surface of the head. 
         [0026]    Each of tufts  20  are oval in cross-section with a 7.62 mm height. The dimensions of the oval are 1.27 mm×2.28 mm. 6 mil filament can be used for tufts  20 . The tuft is tilted away from the center of the head at an angle of about 20 degrees relative to the top surface of the head. The long dimension of the oval cross-section lies along the direction of tilt of tuft  20 . 
         [0027]    Each of tufts  22  are oval in cross-section with a 7.37 mm height. The dimensions of the oval are 0.76 mm×3.05 mm. 6 mil filament can be used for tufts  22 . The tuft is tilted along an imaginary circular line whose center is concentric with the head&#39;s center. The angle of tilt is about 20 degrees relative to the top surface of the head. The long dimension of the oval cross-section is aligned substantially towards the center of the head. 
         [0028]    Each of tufts  24  are oval in cross-section with a 7.62 mm height. The dimensions of the oval are 0.76 mm×1.52 mm. 6 mil filament can be used for tufts  22 . The tuft is tilted along an imaginary circular line whose center is concentric with the head&#39;s center. The angle of tilt is about 12 degrees relative to the top surface of the head. The long dimension of the oval cross-section is aligned substantially towards the center of the head. 
         [0029]    Each of tufts  24  are oval in cross-section with a 7.62 mm height. The dimensions of the oval are 0.76 mm×1.52 mm. 6 mil filament can be used for tufts  22 . The tuft is tilted along an imaginary circular line whose center is concentric with the head&#39;s center. The angle of tilt is about 12 degrees relative to the top surface of the head. The long dimension of the oval cross-section is aligned substantially towards the center of the head. 
         [0030]    Each of tufts  26  are oval in cross-section with a 8.4 mm height. The dimensions of the oval are 0.76 mm×1.52 mm. 6 mil filament can be used for tufts  22 . The tuft is tilted along an imaginary circular line whose center is concentric with the head&#39;s center. The angle of tilt is about 12 degrees relative to the top surface of the head. The long dimension of the oval cross-section is aligned substantially towards the center of the head. 
         [0031]    Turning now to  FIG. 2 , a more detailed description of head  14  will be provided. A plastic base member  30  is supported in neck  12  and is driven by gearing or another driving element (not shown) to oscillate the head. A resilient cushion  32  is made of a thermoplastic elastomer and is positioned within base member  30 . A plastic support member  34  has a number of wholes therethrough which match in number and shape the number and shape of all of the tufts of bristles. Base member and support member can be made of Delrin. Cushion  32  can be made of GLS Dynaflex G 6703 
         [0032]    A pair of catches  36  (only one is visible) in support member  34  engage a pair of openings  38  in base member  30  to secure the support member to the base member in a snap-fit arrangement which securely traps cushion  32  therebetween. Tufts  40  are supported at their bases by the support member. The lower portions of the tufts are not shown in  FIG. 2  but will be described in further detail below. 
         [0033]    Referring to  FIG. 4 , cushion  32  is shown adjacent support member  34 . Only one of the tufts  18  is shown. The non-brushing end of tuft  18  has been melted into a mass  42 . Mass  42  prevents tuft  18  from being withdrawn from its hole when a tensile force is applied to a brushing end  43  of the tuft along a long axis of the tuft. A cylindrically shaped protrusion  44  is provided on cushion  32  and is in contact with mass  42 . At least one protrusion is provided for each tuft on the brush. 
         [0034]    When a compressive force is applied to end  43  of tuft  18  along the long axis of the tuft, the tuft can move in its hole in a first direction  46  into the cushion. Such movement occurs because protrusion  44  acts like a spring, compressing under the force applied to it by mass  42 . When the compressive force is removed the protrusion resumes its original shape, causing tuft  18  to move in its hole in a second direction substantially opposite the first direction. Such action assists in preventing damage to a person&#39;s gums in the event excessive pressure is used during brushing of the teeth. 
         [0035]    Alternatively, mass  42  can be captured within support member  34  while the support member is being formed by injection molding (known as hot-tufting). In this case, cushion  32  is not required. In another alternative, member  34  is ultrasonically welded to base member  30  after the tufts are secured to member  34 . As such, catches  36  and openings  38  are eliminated. 
       Embodiment 2 
       [0036]    Turning now to  FIGS. 5-9 , a second embodiment of a head for an electric toothbrush will be described. A head (support member)  50  supports a multiplicity of tufts of bristles. The bristles all have a diameter of about 6 mil. Of course different filament diameters can be used (e.g. 6.0±0.5 mil). 
         [0037]    A first group of tufts  52  have a round cross-section and extend perpendicular from head  50 . Each tuft includes about 54 bristles per tuft. Tufts  52  rise about 7 mm above the head (the tufts&#39; length) and preferably include bi-filament bristles. Such bristles are coextruded from two different materials, such as nylon 6.12 and nylon 6.10, and bend when exposed to water. All nylons mentioned for this embodiment are preferably polyamid. Further details on such bi-filament bristles can be found in PCT published application WO 98/14092. 
         [0038]    A second group of tufts  54  are oval in shape (i.e. fin shaped) and also extend perpendicular from head  50 . The filaments of this tuft are extruded from a single material such as nylon 6.12 Tufts  54  rise about 7.4 mm above the head. There are about 108 bristles in each tuft  54 . 
         [0039]    A third group of tufts  56  are also oval in shape and rise about 7.4 mm above head  50 . Tufts  56  are preferably made of nylon 6.12 with each tuft including about 108 bristles. Tufts  56  are angled away from vertical by about 6 degrees in a radial direction away from the center of the head (see  FIG. 8 ). 
         [0040]    A fourth group of tufts  58  are round in cross-section and rise about 7.4 mm above head  50 . Such bristles are coextruded from two different materials, such as nylon 6.12 and nylon 6.10, and bend when exposed to water. Each tuft includes about 54 bristles. Tufts  58  are angled away from vertical by about 7.5 degrees in a radial direction away from the center of the head (see  FIG. 8 ). 
         [0041]    A fifth group of tufts  60  are oval in cross-section and rise about 8.3 mm above head  50 . Tufts  60  are preferably made of nylon 6.12 with each tuft including about 108 bristles. Tufts  60  are angled away from vertical by about 7.5 degrees in a tangential (i.e. circumferential) direction. Each tuft  60  is angled towards its closest neighboring tuft  60  (see  FIG. 8 ) which makes the tufts more stable because the paired tufts support each other during brushing. This also assists in reducing bristle wear for these tufts. 
         [0042]    A sixth and final group of tufts  62  are round in cross-section and rise about 7.4 mm above head  50 . Tufts  62  are preferably made of nylon 6.12 with each tuft including about 54 bristles. Tufts  62  are angled away from vertical by about 6 degrees in a tangential (i.e. circumferential) direction. Each tuft  62  is angled towards its closest neighboring tuft  62  (see  FIG. 5 ). 
         [0043]    Endrounding of the bristles is accomplished after they are secured to the head. As such, the angle of tilt away from vertical for applicable tufts is limited to 7.5 degrees in order to obtain the best endrounding. Conventional stapling techniques can be used to secure the single tufts or segments to the head at an angle up to 7.5 degrees. If a tuft angle above 7.5 degrees is desired, an additional degree of freedom is required for the stapling tool (in this case, endrounding will not be as good). 
         [0044]    Tufts  56  and  60  preferably include blue or green wear indicating bristles which are described in detail in U.S. Pat. No. 4,802,255. Oval shaped tufts  54 ,  56  and  60  are actually each made up of two groups of bristles. The oval shape increase the stiffness of these tufts and allows them to penetrate better between teeth than circular tufts. All of the oval shaped tufts have dimensions of about 1.45 mm by 2.9 mm All of the tufts with round cross-sections have a diameter of about 1.5 mm. The diameter of head  50  is about 13.25 mm. In an alternative embodiment, all of the tufts on the head range in length (the rise above the head) between about 6.7 mm to about 8.6 mm. 
         [0045]    The invention has been described with reference to preferred embodiments. 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. 
         [0046]    All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this written document conflicts with any meaning or definition of the term in a document incorporated by referenced, the meaning or definition assigned to the term in this written document shall govern. 
         [0047]    While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.