Abstract:
An electric toothbrush head section and method of manufacture thereof, which head section contains a movable and at least one static bristle bearing components, wherein the static bristle bearing component is interfitted about the exterior of said head section, in a fashion to reduce the seepage of liquid therein.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention pertains to a brush section for an electric toothbrush and a method of manufacture thereof, and more particularly to such a section having a housing with a moving bristle bearing component and at least one static bristle bearing component mounted thereon, wherein the static bristle bearing component is held in interfitting engagement about the exterior of said housing.  
         BACKGROUND OF THE INVENTION  
         [0002]    The benefits of brushing one&#39;s teeth using toothbrushes are well known, and motorized movement in toothbrushes has been the subject of much recent innovation and design activity. The commercial market has seen the introduction, over the last several years, of many different types of motorized toothbrushes. However, an examination of the available published literature describing this technology shows a tendency towards increasingly complex, expensive, and noncommercially feasible methods of achieving motorized motions in the bristles and heads of toothbrushes to aid in more effective cleaning of teeth.  
           [0003]    The commercial marketplace has been divided into tiered price markets. At the higher priced end are complex motorized toothbrushes that provide various motions to the bristles and brush head, which brush heads are replaceable when the bristles become worn. Intermediate priced brushes, which are still relatively expensive for the mass market, provide simpler designs than the more complex higher end toothbrushes and generally still provide replaceable head sections. The lower priced end of the market includes brushes that only vibrate through the use of an offset weight attached to the motor shaft and which provide little true additional cleaning benefit since no vigorous motion is transmitted to the cleaning surface of the teeth; and simplified designed brushes which have generally fixed non-replaceable head sections, having the obvious disadvantage that when the bristles become worn the toothbrush must be replaced.  
           [0004]    U.S. Pat. Nos. 6,000,083 and 6,178,579 disclose low priced electric toothbrushes, wherein the brush head includes a circular moving bristle component preferably located at the end of the brush head distal to the brush handle and adjacent to which circular moving component is a static bristle component. The circular moving bristle component is disclosed as containing stiffer bristles to aid in the deep cleaning and plaque removal process further back in the user&#39;s mouth; while the static bristle component contains softer bristles, so as not to damage the gums. This combination of moving and static bristles provides the user with a more traditional, larger brush head than other electric brushes, which merely contain circular bristle bearing heads; which larger brush head permits the user to brush his teeth in the typical manner of an up and down fashion. However, as disclosed within 6,000,083 and 6,178,579, the static bristle component is integrally molded as part of the overall housing of the toothbrush. This integral configuration of the static bristle component with the housing makes for inefficient tufting of the static bristle component, as the housing component containing the static bristle component must itself be manipulated into a tufter and leads to inefficiencies when a new design static bristle pattern is desired, as the entire mold of the housing component containing the static bristle component must be replaced.  
           [0005]    U.S. Pat. No. 5,186,627 discloses a non-powered toothbrush having a combination of a rotatable and fixed brush sections, wherein the fixed brush section is in snap-fit engagement internal to the outer cover of the toothbrush. Such a configuration, with the fixed brush section being retained within a surrounding cover, will allow seepage into the brush head and the accumulation of liquid therein, which may promote the undesired growth of bacteria and mold therein.  
           [0006]    There is thus a need in the art for a design for an electric toothbrush head section which contains a combination of a movable and static bristles, wherein the static bristle component is not integral with the housing of the brush head section, such that the static bristle component can be efficiently tufted; such that a new design for the static component&#39;s bristle pattern can be implemented without replacing the mold for the overall head section in which the static bristle component is contained; and such that seepage into the brush head is reduced to avoid the undesired growth of bacteria and mold therein.  
         SUMMARY OF INVENTION  
         [0007]    The present invention is directed to an electric toothbrush head section containing a housing on which is mounted a moving bristle bearing component and at least one static, i.e. fixed or non-movable, bristle bearing component and to a method of manufacture thereof, wherein the static bristle bearing component is mounted so as to at least partially surround the exterior the housing. In a preferred embodiment, the moving bristle bearing component is circular in cross-section and the static bristle component is u-shaped, wherein the sides of the “u” are permanently, mechanically interfitted about the exterior of the housing. The relatively small size and u-shaped configuration of the static bristle bearing component provides for ease of manipulation thereof, as it is manufactured and tufted. Further, the u-shape provides for an overlap of the static bristle bearing component about the exterior of the housing upon which it is mounted, to reduce seepage of liquid into the head section, to reduce the undesirable growth of bacteria and mold therein.  
           [0008]    The preferred circular bristle bearing component is located adjacent the front end of the head section, distal from the handle of the electric toothbrush from which said head section extends. The preferred circular bristle bearing component may rotate, swivel, gyrate, oscillate or reciprocate about an axis substantially normal to the longitudinal axis of the head section. The static bristle component or components may be located adjacent to the circular bristle bearing component and on one or more sides thereof.  
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0009]    The ensuing description of the invention will be understood more readily from the accompanying drawings, in which: FIG. 1 is front view of an electric toothbrush containing a head section of the present invention having a circular bristle bearing component and a static bristle bearing component; FIG. 2 is side elevation view of the electric toothbrush of FIG. 1; FIG. 3 is fragmentary sectional view of the side of the head section of the electric toothbrush of FIG. 1; FIG. 4 is a sectional view of FIG. 1 along line  4 - 4 , showing a preferred embodiment of the present invention, wherein the u-shaped static bristle bearing component is mechanically held in interfitting engagement with the brush head section by a rib and groove closure. 
     
    
     DETAILED DESCRIPTION  
       [0010]    Referring to FIGS. 1 and 3, which respectively illustrate, an elongated electric toothbrush  20  having at its first end a handle  24  and the details of a head section  22  of the present invention. As shown in FIG. 3, said head section  22  with a drive shaft  15  running longitudinally therethrough, contains a housing  32 ; which housing  32  has mounted thereon a combination of a fixed, non-movable bristle bearing component  14  and a movable bristle bearing component  12 . Which drive shaft  15  is drivably coupled on one end to said movable bristle bearing component  12  and on the other end to a motor located in said handle  24 . The static bristle bearing component  14  is preferably u-shaped and is mounted on and about the exterior of said housing  32  in an inverted position, such that said housing  32  is at least partially surrounded on three sides by the inverted “u”. The inverted “u” is preferably secured in place by an interfitting closure about the exterior of said housing  32 . The interfitted closure is preferably a permanent closure, to avoid the possibility of the static bristle component  14  becoming loose during usage and being swallowed by or choking the user.  
         [0011]    The head section  22  of the present invention, as shown in FIG. 1, is integrally attached, i.e. permanently attached, to the balance of the electric toothbrush handle  24 . However, as is well known in the art, the present invention can alternatively be used in conjunction with a head section  22  which is demountably attached, i.e. temporarily attached, to the balance of the electric toothbrush handle  24 .  
         [0012]    [0012]FIG. 2 is a side elevation view of the electric toothbrush  20  of FIG. 1, wherein the preferred u-shaped static bristle bearing component  14  of the present invention is shown in two positions, a first position as a tufted component aligned as an inverted “u” above the housing  32 , which tufted component is then interfitted about the exterior of the housing  32  mechanically, as shown by the arrow; whereby it assumes the second position as part of the completed toothbrush  20 . The relatively small size of the static bristle bearing component  14  (as shown), in combination with its u-shape, allow easy manipulation of multiple static bristle bearing components, such that such multiple components can be simultaneously pre-tufted in an efficient manner.  
         [0013]    Referring again to FIG. 3, the movable bristle bearing component  12 , is preferably circular in cross-section, as shown with bristle tufts  10  extending therefrom. The movable bristle bearing component  12  is movably supported by an axis  13 ; and is motivated by said drive shaft  15 , a preferred motivation means as disclosed in U.S. Pat. No. 5,625,916. The movable bristle bearing component may be driven so as to rotate, swivel, gyrate, oscillate or reciprocate about an axis substantially normal to the longitudinal axis of the head section.  
         [0014]    In the present invention, the movable bristle bearing component  12  is in combination with a static bristle bearing component  14 , each component having bristle tufts  10  also extending therefrom. This combination of a movable bristle bearing component  12  and a static bristle bearing component  14 , is preferably configured as shown in FIGS. 1, 2, and  3 , wherein the movable bristle bearing component  12  is located adjacent the front end of the head section  22 , i.e. distal from the handle  24 , and the static bristle bearing component  14  located immediately adjacent thereto. The static bristle bearing component  14  may alternatively be located adjacent the front end of the head section  22  and the movable bristle bearing component  12  located adjacent thereto and more proximate to the handle  24 , as shown in U.S. Pat. No. 6,178,579 and 6,189,693. Further, the movable bristle bearing component  12  may be located more centrally within the head, with the static bristle bearing component  14  located on opposite sides of the head with respect thereto, as shown in U.S. Pat. Nos. 5,186,627 and 6,000,083.  
         [0015]    [0015]FIG. 4, a sectional view of the head section of the present invention looking along section  4 - 4  of FIG. 1, shows a preferred interfitting rib  28  and groove  26  configuration for permanently attaching the static bristle bearing component  14  about the exterior of the housing  32  of the head section  22 . The rib may be carried by the housing  32 , as shown, or by the static bristle bearing component  14 . To hold the static bristle bearing component  14  securely in position along the longitudinal axis of the head section  22 , a retaining wall  30  is provided extending transverse to the longitudinal axis of the brush head  22  on the side of the static bristle bearing component  14  adjacent to the handle  24 ; and a pair of extending flanges (not shown) are provided which extend on each side of the head section  22  at the other, i.e. front end, of the static bristle bearing component located distal from the handle  24 . The pair of extending flanges are positioned to seat against the front end of the static bristle bearing component  14 ; while, the other end of the static bristle bearing component  14  seats against the retaining wall  30 , such that the static bristle bearing component  14  is held securely between the pair of extending flanges and the retaining wall  30 .  
         [0016]    In other embodiments, the static bristle bearing component  14  may be held about the housing  32  by other known male/female interfitting means which lock into a permanently secured arrangement, or by being permanently welded thereon. Such welding can be by ultrasonic, laser, hot air or other known techniques, which while more costly than a mechanical interfitting closure, may provide the additional benefit of further reducing seepage of liquid into the toothbrush head section  22 . Further, the joining of the static bristle bearing component  14  to the housing  32  may be by use of an adhesive bond therebetween.  
         [0017]    The static bristle bearing component  14 , and the housing  32  of the head section  22  of the present invention can be molded of a variety of flexible resilient plastic materials, such as polyamide, i.e. nylon; polyester or a co-polyester; acrylonitrile butadiene styrene (ABS); polycyclohexylene dimethylene terphthalate that is acid modified (PCTA); or polypropylene; preferably polyproplyene; or, if a transparent appearance is desired of polyester. A preferred polypropylene is available from Montell North America, Inc., of Wilmington, Del., sold under the trade-designation PP6331. Other suitable polypropylenes include those available from Amoco Polymers, Inc., Alpharetta, Ga. 30202-3914, sold under the trade-designation 7635 and from Huntsman Corporation, Longview, Tex. 75603, under the trade-designation Huntsman Polypropylene P4G3Z-039.