Abstract:
A toothbrush having a replaceable head attachment is disclosed. The toothbrush includes a brush head that is releasably engaged to a handle portion and utilizes a threaded engagement configuration between the two components.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This is a continuation of application Ser. No. 10/659,788, filed Sep. 10, 2003, which claims the benefit of U.S. Provisional Application No. 60/410,853, filed Sep. 13, 2002, the substances of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to the field of toothbrushes, and more particularly, the invention relates to the field of electrically powered toothbrushes.  
       BACKGROUND OF THE INVENTION  
       [0003]     Electric toothbrushes are known that utilize a replaceable or interchangeable brush head which is releasably engageable with a handle or body portion. For example, U.S. Pat. No. 5,404,608 to Hommann discloses an electric toothbrush having a handle with a push-on brush component. U.S. Pat. Nos. 4,880,382 to Moret et al. and 5,435,034 to Bigler et al. disclose electric toothbrushes having brush heads that are replaceable and removable from a handle or body portion of the brush. Both the &#39;382 patent and the &#39;034 patent utilize a slotted engagement mechanism between the brush head and the handle portion of the brush. U.S. Pat. No. 5,465,444 to Bigler et al. describes an electric toothbrush having a brush head that is said to “slip-on” a handle portion.  
         [0004]     Although satisfactory in many respects, a need exists for an electric toothbrush having a removable brush head that may be securely and easily engaged with a handle or body portion of the toothbrush that is more compact compact and robust.  
       SUMMARY OF THE INVENTION  
       [0005]     An electric toothbrush is provided. The electric toothbrush has a housing defining a hollow interior having a motor and a first shaft disposed therein that is operatively connected to the motor. The housing has an engagement member extending along a longitudinal axis of the housing from an end thereof. The engagement member includes a first thread helically extending the said engagement member.  
         [0006]     A brush head is releasably connected to the handle. The brush head has a movable bristle carrier at a first end and a second shaft operatively connected to the movable bristle carrier. The brush head has a receiving region at a second end of the brush head opposite the first end. The receiving region has an engagement surface with a second thread helically extending along the annular engagement surface. The first thread and second thread form a threaded connection that releasably couples the brush head to the handle when one of the handle or the brush head is rotated about the longitudinal axis. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The present invention may take form in various components and arrangements of components, and in various techniques, methods, or procedures and arrangements of steps. The referenced drawings are only for purposes of illustrating preferred embodiments, they are not necessarily to scale, and are not to be construed as limiting the present invention.  
         [0008]     It is believed that the present invention will be better understood from the following description taken in conjunction with the accompanying drawings in which:  
         [0009]      FIG. 1  is a perspective view of a preferred embodiment electric toothbrush in accordance with the present invention.  
         [0010]      FIG. 2  is a perspective view of the preferred embodiment toothbrush shown in  FIG. 1  in a partially disassembled state in which the brush head is removed from the body portion of the brush.  
         [0011]      FIG. 3  is a partial side view of the toothbrush shown in  FIGS. 1 and 2  detailing the engagement of the brush head and the body or handle portion of the brush.  
         [0012]      FIG. 4  is a detailed view illustrating the engagement and orientation of the brush head and handle portion of the toothbrush shown in  FIG. 3 , in which the components are separated from one another.  
         [0013]      FIG. 5  is an end view of the brush head component shown in  FIG. 4 , taken with respect to line  5 , 5 .  
         [0014]      FIG. 6  is an end view of the handle portion of the brush assembly shown in  FIG. 4  taken along line  6 , 6 .  
         [0015]      FIGS. 7A  to  7 C are cross-sectional side views showing engagement of first and second shafts. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     All patents and patent publications referenced herein, including U.S. Provisional Application No. 60/410,853, filed Sep. 13, 2002, are incorporated herein by reference.  FIGS. 1 and 2  illustrate a preferred embodiment electric toothbrush  10  in accordance with the present invention. The preferred embodiment toothbrush  10  comprises a handle or body portion  30 , an end cap  20  disposed at one end of the handle portion  30 , and a brush head  40  disposed at an end opposite the end at which the end cap  20  is disposed. The handle  30  preferably defines a hollow interior region that is accessible from an open end defined at the end of the handle at which the end cap  20  is disposed. The hollow interior region defined within the handle  30  is also accessible from the end to which the brush head  40  is attached. The preferred embodiment toothbrush  10  also comprises a plurality of bristles  50  disposed on or near a distal-most end of the brush head  40 . Most preferably, a movable bristle carrier is disposed on the end of the brush head that is driven by an electric motor disposed within the handle  30 . The bristle carrier preferably supports and retains a collection of bristles that move along with the movable bristle carrier during operation of the electric toothbrush. Most preferably, the plurality of bristles  50  contain these movable bristles, and additionally include stationary or static bristles that are disposed along the brush head and preferably around the movable bristle carrier and its bristles. The preferred embodiment toothbrush  10  also includes an actuator or switch  60  accessible along the exterior of the handle  30  for actuating the motor disposed within the interior of the toothbrush  10 . A drive mechanism operatively interconnects the motor and movable bristle carrier to impart movement, e.g. translational or oscillating movement, to the movable bristle carrier upon actuation of the motor by the switch  60 . The present invention is not particularly directed to the bristles disposed on the brush head or the configuration of the movable bristle carrier and so extensive description of those aspects are not set forth herein. These aspects are the subjects of many of the Assignee&#39;s other patent applications and patents.  
         [0017]      FIG. 2  illustrates the preferred embodiment electric toothbrush  10  in a partially disassembled state in which the brush head  40  is removed and separated from the handle portion  30 . It can be seen that the handle portion  30  includes an engagement member  32  extending in a direction generally along the longitudinal axis of the toothbrush. The longitudinal axis is shown in  FIG. 2  as axis L. Defined along this end of the handle  30  is a shoulder region formed from an annular surface  34  that extends from the main exterior of the housing  30 , designated as the handle outer surface  31 , to the engagement member  32 . The corner or boundary between the generally smooth contoured handle outer surface  31  and the annular surface  34  is designated as corner  36 . As will be appreciated, the corner  36  extends about the periphery of the handle  30  and generally separates the outer contoured surface of the handle  30  from the annular surface  34 . The brush head  40  provides a distal end  42  which, upon engagement with the handle  30  of the toothbrush  10 , generally borders or is immediately adjacent to the corner  36  of the handle  30 .  
         [0018]      FIG. 3  is a detailed side view of a portion of the handle  30  and the brush head  40 , further illustrating the engagement between those two components.  FIG. 3  illustrates that the engagement member  32  is received and retained within a receiving region defined within an end of the brush head  40 . Preferably, the outer surface of the brush head  40  is contoured and sloping in the same manner as the outer surface of the handle  30 . The brush head outer surface is designated as  41  in the referenced figures. Most preferably, the outer contours of the two components, i.e. the brush head  40  and the handle  30 , are such that when those components are engaged with each other as shown in  FIG. 3 , a single, continuous common surface is formed from the outer surfaces of the components, i.e. surfaces  31  and  41 . That is, the degree of contour or slope of an outer surface of one of the components is continued and exhibited by the other component engaged thereto.  
         [0019]      FIG. 4  details the engagement structures between the brush head  40  and the handle portion  30 , and illustrates those components as separated from one another. Specifically, the handle or body portion  30  includes the annular surface  34 , from which extends the engagement member  32 . The engagement member  32  is preferably in the shape of a cylinder, although conical configurations are also encompassed by the present invention. The engagement member  32  preferably extends along and is concentrically disposed about the longitudinal axis L of the toothbrush. Defined along the cylindrically shaped engagement member  32  is a screw member or thread  33  that is oriented such that it extends generally radially outward from an outer surface  35  of the engagement member  32 . The thread  33  helically extends along the length of the engagement member  32 , or substantially so. The thread  33  has a major diameter, a minor diameter, a pitch diameter, and a pitch. The thread engages a corresponding thread  44  disposed on brush head  40 . The thread is configured to facilitate engagement between a first shaft disposed within the handle  30  and a second shaft disposed within the brush head  40 , as discussed more fully hereafter. The first and second shafts can reciprocate, rotate, oscillate, or gyrate to transmit motion from an electric motor in the handle to the movable bristle carrier disposed at the end of the brush head  40 .  
         [0020]     With regard to the brush head  40 , a recessed receiving region is generally defined within the distal end  42  of that component. A sealing lip  45  extends around the periphery of the distal end  42  of the brush head  40 . An annular engagement surface  43  having a complimentary screw member or thread  44  projecting from its cavity walls is provided within the receiving region, adjacent the sealing lip  45 . That is, the thread  44  projects from the surface  43 , toward the interior of the receiving region defined in part by the surface  43 . The thread  44  helically extends along the annular engagement surface  43 . The thread  44  engages to thereby form a threaded connection between the brush head  40  and handle  30 . The thread  44  can be provided as either a male thread or a female thread as can the thread  33  of the engagement member  32 . The brush head  40  further defines a channel  49  extending from the annular engagement surface  43  within its interior, and preferably extending co-linearly with the longitudinal axis L of the toothbrush  10 .  
         [0021]      FIG. 5  is an end view of the brush head  40 . The brush head  40 , as previously noted, includes a sealing lip  45  that extends inward from the distal end  42 . The sealing lip  45  leads to the annular engagement surface  43 . That surface, i.e. the annular engagement surface  43 , extends between the sealing lip  45  and the channel  49  extending within the interior of the brush head. A stop surface  41  is provided between the entrance to the channel  49  and the annular engagement surface  43 . The stop surface is preferably oriented and generally perpendicular to the longitudinal axis of the toothbrush  10 .  
         [0022]      FIG. 6  illustrates an end view of the preferred embodiment handle  30  of the brush  10 .  FIG. 6  illustrates the outer surface  31  of the handle  30  as it extends to the corner  36 .  FIG. 6  further illustrates the annular surface  34  extending between the corner  36  and the cylindrically shaped engagement member  32  having a thread  33  formed thereon.  FIG. 6  also illustrates an annular sealing surface  37 . The sealing surface is generally defined along the distal end of the engagement member  32 .  
         [0023]     Insertion of the engagement member  32  within that receiving region is achieved by rotating one of the handle  30  or the brush head  40  with respect to the other. Accordingly, upon insertion, the engagement member  32 , and thus the handle  30 , may not be withdrawn from the brush head  40 . Withdrawal or separation of the components  30  and  40  is achieved by rotating, in an opposite direction, one component with respect to the other. It will be understood that the helical orientation of each of the threads  33  and  44  is the same so that one thread may slide or otherwise be translated past the other.  
         [0024]     As previously noted, it is preferred that a motor, power source, and drive mechanism be disposed within the hollow interior region defined within the handle  30  of the preferred embodiment toothbrush. A wide array of drive motor and gearing configurations may be utilized in the preferred embodiment toothbrushes described herein. For example, various drive mechanisms described in U.S. Publication No. 20020162180A1 and U.S. Pat. Nos. 6,178,579; 6,189,693; 6,360,395; and 6,371,294 may be suitable. The drive mechanism includes a first shaft  50  ( FIG. 7 ) disposed within the handle that is operatively connected to the motor. An interconnecting structure is provided that releasably couples the first shaft in the handle  30  with a second shaft  52  in the brush head  40  so that motion is transmitted from the motor (not shown) to the movable bristle carrier on the brush head  40 . The interconnecting structure should both couple the first and second shafts and be compatible with the rotational movement associated with engagement of the threads  33  and  44 .  
         [0025]     Referring to  FIG. 7 , a preferred interconnecting structure for coupling the first shaft  50  in the handle  30  and the second shaft  52  of the brush head  40  that is suitable for use with the threads  33  and  44  is illustrated. The interconnecting structure couples the first and second shafts when the brush head  40  threadedly engages the handle  30 . The interconnecting structure comprises a notch  54  on the first shaft  50  and a radially extending tab  58  that engages the notch  54  to couple the first and second shafts  50  and  52 . The tab  58  extends from an arm  59  connected to the second shaft  52  that is offset from the centerline thereof. The tip  53  of the first shaft is substantially cylindrical in shape so that the tab  58  can easily traverse the outer surface of the first shaft as the brush head  40  is rotated through the engagement length of the threads  33  and  44 . The distal most end of the first shaft  50  is also rounded or chamfered to facilitate guiding the tab  58  onto the outer cylindrical surface of the first shaft  50 . The second shaft  52  should be flexible and resilient or otherwise deflectable enough to permit the extension  56  to be radially displaced, as best seen in  FIG. 7B . A spring  57  can be provided in the brush head  40  to radially bias the second shaft  52  in order to accommodate the deflection of the second shaft  52 . An annular gap  62  is provided between the first shaft  50  and the inner surface  64  of the handle  30  that is sufficient to permit the tab  58  and least a portion of said arm  59  to pass there through. The annular gap  62  preferably extends about the entire outer surface of the first shaft  50  (i.e., about the entire perimeter or circumference (if cylindrical) of the first shaft  50 ), although the gap  62  may extend about less where the brush head  40  is rotated less than 360° to engage the notch  54  and the tab  58 . As previously discussed, however, it is preferred to rotate the brush head  40  at least about 360° about the longitudinal axis L to provide sufficient engagement between the threads  33  and  44 . The pitch of the threads  33  and  44  is preferably selected to provide a smooth engagement between the notch  54  and the tab  58  (or other interconnecting structures releasably coupling the first and second shafts) as the brush head  40  is rotated and translated along the longitudinal axis L of the toothbrush. If the pitch is too low (i.e., too few threads per mm), the tab  58  and notch  54  might bind during engagement because the thread lead angle is too great. If the shafts reciprocate along the longitudinal axis L, the pitch should also be selected to accommodate the amount of travel associated with the first and second shafts so that engagement of the notch  54  and tab  58  will occur regardless whether the first or second shafts are at the beginning or end of their stroke. The pitch should also be selected to provide a reasonable amount of rotation about the longitudinal axis L so that excessive rotation of the handle  30  or brush head  40  is not required yet sufficient thread engagement is provided for strength. Preferably, the amount of rotation is between about 180° and about 540° about the longitudinal axis L of the toothbrush  10 . In another embodiment, the pitch is selected to provide between about 270° and about 450° of rotation about the longitudinal axis L of the toothbrush  10 . The pitch is preferably between about 1 and about 5 mm and more preferably between about 2 and about 3 mm. A square thread profile is preferred, although other thread profiles can be used.  
         [0026]     Techniques known to those of skill in the art, such as injection molding, can be used to manufacture the toothbrush of the present invention. The housing and the brush head may be formed from a wide array of polymers. In the following description of the preferred polymer materials for use herein, the abbreviations that are commonly used by those of skill in the art to refer to certain polymers appear in parentheses following the full names of the polymers. The polymer is preferably polypropylene (“PP”), or may be selected from the group consisting of other commercially available materials, such as polystyrene (“PS”), polyethylene (“PE”), acrylonitrile-styrene copolymer (“SAN”), and cellulose acetate propionate (“CAP”). These materials may be blended with one or more additional polymers including a thermoplastic elastomer (“TPE”), a thermoplastic olefin (“TPO”), a soft thermoplastic polyolefin (e.g., polybutylene), or may be selected from other elastomeric materials, such as etheylene-vinylacetate copolymer (“EVA”), and ethylene propylene rubber (“EPR”). Examples of suitable thermoplastic elastomers herein include styrene-ethylene-butadiene-styrene (“SEBS”), styrene-butadiene-styrene (“SBS”), and styrene-isoprene-styrene (“SIS”). Examples of suitable thermoplastic olefins herein include polybutylene (“PB”), and polyethylene (“PE”).  
         [0027]     The present invention may further utilize features, aspects, components, materials, and characteristics from one or more of the following published patent applications or issued patents: WO 01/29128; U.S. Pat. No. 6,000,083; U.S. Des. Pat. No. 432,312; U.S. Des. Pat. No. 433,814; U.S. Pat. No. 6,178,579; U.S. Pat. No. 6,189,693; U.S. Pat. No. 6,311,837; U.S. published patent application 2002/0032941; U.S. Pat. No. 6,360,395; and U.S. Pat. No. 6,371,294.  
         [0028]     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 reference, the meaning or definition assigned to the term in this written document shall govern.  
         [0029]     The embodiments described herein were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.