Abstract:
A decorative piece in the form of a topper designed to seat at the base of the shaft and extending from the handle body of a powered toothbrush is provided. The topper is formed as a single molded piece on top of a base ring having a central hole that fits over the shaft and a lower skirt that mates with the handle. The base ring includes grooves or other indentations about the central hole that receive inflow from the topper when it is molded. According to one embodiment, to construct the topper, the base ring is held in place with respect to the topper mold and molten or otherwise-liquid plastic is injected into the mold so that it fills the mold cavity and thereby flows into the indentations in the base ring, thereby securing the topper to the base ring when the decorative feature hardens sufficiently. The base ring and topper can then be slid over the shaft into a final mounted position on the assembled brush.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This is a continuation of application Ser. No. 10/237,902, filed Sep. 9, 2002, now abandoned the substance of which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention relates to powered toothbrushes, and more particularly to decorations applied to powered toothbrushes and methods for attaching such decorations. 
   BACKGROUND OF THE INVENTION 
   Powered toothbrushes are becoming an increasingly desirable item for both adults and children. A variety of inexpensive semi-disposable and fully disposable powered toothbrushes are now available on the market. In order to interest children in developing good oral hygiene habits, many toothbrushes, including powered toothbrushes, are provided with decoration relevant to childrens&#39; tastes. One of the more elaborate and desired forms of decoration is a sculpted feature applied to a portion of the brush handle. Such sculpted features can represent well-known cartoon characters or any other relevant three-dimensional subject matter including desirable toys. 
   The internal mechanism and case construction of powered toothbrushes varies widely. In general, all toothbrushes include a handle that contains the battery and a driving motor as well as a switch. Extending from the handle is a thinner, elongated shaft, that at its end includes one or more moving heads. Power is transmitted from the handle to the heads via various drive shaft arrangements. The cases of powered toothbrushes are formed from one or more pieces (shell halves) that are often joined together using adhesives, ultrasonic welding or other joining techniques. To incorporate a piece that represents a decorative feature (e.g., a cartoon character, toy etc.) it may be necessary to employ advanced construction and molding techniques. However, these techniques must not drive the cost of construction of the relatively inexpensive toothbrush too high or it will be uncompetitive in the mass market. 
   SUMMARY OF THE INVENTION 
   This invention overcomes the disadvantages of the prior art by providing a decorative piece in the form of a topper designed to seat at the base of the shaft and extending from the handle body of a power toothbrush. The topper is formed as a single molded piece on top of a base ring having a central hole that fits over the shaft and a lower skirt that mates with the handle. The base ring includes grooves or other indentations about the central hole that receive inflow from the topper when it is molded. 
   According to one embodiment, to construct the topper, the base ring is held in place with respect to the topper mold and molten (or otherwise-liquid) plastic is injected into the mold so that it fills the mold cavity and thereby flows into the indentations in the base ring, thereby securing the topper to the base ring when the decorative feature hardens sufficiently. The base ring and topper can then be slid over the shaft into a final mounted position on the assembled brush. 
   In another embodiment the handle body can be sealed using an outer cover or sleeve. This cover or sleeve can be seamless about its circumference and open at one end while closed at the bottom end. In this manner a 360° label/decal, such as a heat-transferred label/decal can be applied to the sleeve. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention description below refers to the accompanying drawings, of which: 
       FIG. 1  is a side cross section of an assembled power toothbrush with an exemplary topper placed thereon according to one embodiment; 
       FIG. 2  is an exploded perspective view of the toothbrush of  FIG. 1 ; 
       FIG. 3  is a partial perspective view of a topper base ring and decorative feature being formed in a mold according to an embodiment of this invention; 
       FIG. 4  is a more detailed side cross section of the engagement of the topper decorative feature of  FIG. 1  with the base ring; 
       FIG. 5  is a top view of an exemplary decorative feature of  FIG. 1  in engagement with the base ring; 
       FIG. 6  is a front cross section of an assembled topper and a base ring on a brush shaft detailing the seal between the shaft and the topper; 
       FIG. 7  is an exploded perspective view of the assembly of a topper onto an exemplary toothbrush according to another embodiment of this invention; 
       FIG. 8  is a cross section of a technique for engaging the base ring onto a handle body of a power toothbrush according to an embodiment of this invention; and 
       FIG. 9  is a cross section of a technique for engaging a base ring onto a handle body of a toothbrush according to an embodiment of this invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a side cross-section of an exemplary powered toothbrush  100  according to an embodiment of this invention. The featured toothbrush includes a unique dual head  102  assembly at the end of a hollow toothbrush shaft  104 . For the purposes of this illustration, the internal mechanism of the toothbrush has been removed. In general, such a mechanism can include a drive shaft passing through the hollow shaft  104  to drive the toothbrush heads  102  in a continuous or reciprocating motion about respective rotational axes  105 . A motor, gearing and battery (not shown in  FIG. 1 ) are positioned within the main body interior cavity  106  of the toothbrush, which also acts as a handle. The size of the main body handle, and its shape, can be designed to accommodate the hand of an adult or a small child as appropriate. The toothbrush is activated by an exposed button  108  that can have both momentary contact and continuous-on functions. In the illustrative embodiment, the shaft is formed integrally with the inner handle body  110 . A top step  112  is provided between the shaft and the handle body  110 . 
   With reference also to  FIG. 2 , the shaft  104  and handle body  110  are formed as separate shell halves  114  and  116  in this embodiment. The halves are joined along a seam line using appropriate adhesives, welding or fasteners. In this embodiment, an outer handle cover or sleeve  122  is also provided. The handle cover includes a bottom  124  that seals the hollow opening  126  in the bottom of the handle  110 . The cover  122  can include a variety of shapes and/or graphic patterns  125  thereon. Likewise, the handle cover can be formed as a more complex outer shape such as a car body or other desirable shape  129 . The sculpted features  131  (shown in phantom) of the complex sleeve shape are built up from an internal cavity shape  133  that conforms to the shaped of the handle body  110 . 
   Notably, where a straight cylindrical (for example, circular, polygonal or elliptical cross section) sleeve is employed (exemplary sleeve  122 ), the ability to construct the sleeve as a seamless cup allows the inner seam of the shell halves  114  and  116  to be obscured and a desirable “360 degree” (θ) decal  135  to be applied using heat transfer  137  or other techniques. The resulting finished graphic appears very smooth and essentially seamless, wrapping around the entire perimeter of the cover or sleeve  122 . It is removably secured to the body  110  using a screw  130  that threads into a dog  132  near the opening  126 . A variety of other securing techniques can be employed. In addition, in an alternate embodiment, the outer sleeve or cover  122  can be omitted and a cap or hatch (see for example  FIG. 7 ) can be used to secure the opening  126 . Batteries (see  FIG. 2 ) are provided through the opening and appropriate connector contacts ( 153 ) can be provided at the bottom  124  of the cover or sleeve  122 . Note that the sleeve can be sealed against liquid infiltration using an appropriate sized O-ring  117  ( FIG. 1 ) seated within a circumferential cutout  115  ( FIG. 2 ) on the upper end of the body handle wall  110 . This O-ring  115  seals against the inner wall of the sleeve, thus ensuring that the internal mechanism and batteries remain free of contamination by water or foreign debris (e.g. toothpaste, plaque, etc.). 
   As a further decorative feature, the toothbrush of this invention includes a topper  140  mounted over the body handle shoulder  112  and surrounding the lower portion of the shaft  104  adjacent to the shoulder  112 . The topper  140  includes a base ring  142  and the decorative character or feature  144  extending upwardly away from the base ring  142 . Note that the base ring is sized so that it is essentially flush with the upper end  146  of the sleeve or cover  122 . In addition, the base ring includes a hole  148 , through which is received the button  108 . The hole may be enclosed on all sides, or may be formed as an open mounting of the ring  142  onto the body shoulder  112  during assembly. 
   With further reference to  FIG. 2 , the assembled base ring  142  and feature  144  of the topper  140  are assembled onto the toothbrush, in this embodiment, by sliding them over (arrow  150 ) the distal end  152  of the shaft  104 . In general, the sliding action occurs before the heads  102  are applied to their internal drive gearing and axles  149  (shown schematically), but after the halves  114  and  116  of the shell are joined together with the mechanism (battery  151 , contacts  153 , motor  155 , switch  156 , gearing  157  and driver shaft  159 ) (shown schematically) sandwiched between the pre-assembly shell halves  114  and  116 . The ring  142  is slid downwardly along the shaft until it seats around the body  110  and firmly against the shoulder  112 . Note that the topper includes an axial through-hole  155  to facilitate sliding along the shaft. The details of the shape and size of this hole are described further below. 
   In accordance with the unique topper arrangement of this invention,  FIG. 3  details a schematic mold for constructing a decorative feature  144  (shown in phantom) on top of the ring  142 . It should be noted that the ring of this embodiment is typically formed from the same material as the body shell. For example, the material can be a rigid plastic such as ABS or polystyrene. The feature  144  is typically constructed from a softer plastic such as SEBS or TPU TPE (i.e. a soft polyvinylchloride (PVC)). In accordance with  FIG. 3 , two or more mold halves  160  and  162  are joined around an already completed base ring  142 . The mold halves each include an associated injection channel  170  and  172  through which molten or otherwise liquefied plastic is injected. The cavity  170  defines a negative of the shape of the feature. A mandrel or other cylindrical member  176  is provided at the center of the feature and through a hole  178  in the base ring  142  in order to maintain the axial through-hole ( 155 ) described above. In one embodiment, the mandrel can be inserted through the bottom of the base ring and can be removed after the forming of the feature is complete. A seal  180  prevents plastic from escaping from the base ring. 
   Referring also to  FIGS. 4 and 5 , the base ring  142  includes two or more concentric grooves  180 . The grooves  180  are designed to provide additional holding area for the plastic feature  144 . When the feature  144  is molded, the adhesive properties of the plastic tend to join it firmly to the ring  142 . The joint is further reinforced by the flow of plastic into the grooves  180 . In one embodiment, the grooves have a depth DG of approximately 0.04 inch. The overall thickness TB of the top of the base ring  142  is approximately 0.11 inch and the thickness TS of the side skirt of the base is approximately 0.08 inch. Likewise, the thickness of the outer cover  122  can be approximately 0.08 inch. 
   In this embodiment, the grooves  180  are shaped as inwardly tapering wedges (in cross section). However, a variety of shapes can be formed including a square or rectangular cross section, a curved/semi-circular cross section or even an undercut dovetail-shaped cross section. In addition, while two concentric semi-circles are employed in this embodiment, it is contemplated that more or fewer groove formations can be employed. Likewise, the formations need not be circular, but can be ellipse-shaped, rectangular or any appropriate irregularly-sized shape. In addition, while continuous, unbroken grooves are used according to this embodiment, the term(s) “groove” or “grooves” should be taken broadly to include a variety of broken structures including segmented grooves or even a plurality of individual holes. In general, any formation on the surface of the base ring that facilitates greater gripping of the feature when it is molded onto the base ring is contemplated as a “groove” according to this invention using the above formation approach no additional adhesive is required between the feature and base ring. Note that the size of the feature&#39;s contact surface with respect to the base ring top is highly variable. That is, the feature can contact a relatively small area with respect to the total area of the base ring. Likewise, the feature can contact virtually the entire top surface of the base ring. The top surface grooves are adapted in size, shape and layout to accommodate the desire contact surface profile. 
   It is also expressly contemplated that the base ring and its associated top surface can be irregular or sculpted in shape. The top surface need only enable liquid plastic to be laid thereupon for joining upon hardening. In addition the feature may extend outwardly to a width/diameter that is significantly greater than the top surface&#39;s perimeter. 
   The  FIG. 6  illustrates the topper assembly  200  mounted on a handle body  202  according to an alternate embodiment. Before discussing in detail the topper assembly  200 , the feature  202  will be discussed in further detail. This discussion applied generally to the above-described feature  144  and any other feature to be employed according to an embodiment of this invention. The feature  202  includes a central axial hole having a gap  206  along its length formed between the inner wall  208  of the hole and the outer wall  210  of the toothbrush shaft  212 . In one embodiment, the gap can be approximately 0.015 inch. This gap ensures that when the feature is passed over the shaft, or (as described below) the shaft is passed over the feature, that it is not bound by excessive friction. In order to ensure an appropriate seal and a secure friction fit between the outer wall  210  of the shaft  212  and the feature  202 , an upper lip  214  is provided at the top end of the feature  202 . The upper lip has an inner diameter that, in a free-unattached state, is slightly smaller than the outer diameter of the shaft  212  in the region of final fitment between the shaft and feature. Note that the shaft may be tapered, and thus, its outer diameter may vary along its length—accordingly, the lip inner diameter is sized with the taper in mind. Since the decorative topper feature  202  is formed from a pliable plastic in this embodiment, slight deformation at the lip  214  is accommodated as the shaft and feature slide with respect to each other into a final fitment. It is, of course, contemplated that the topper feature can be formed from more rigid material. In such an instance, a lip can be formed to include a sealing member, such as an O-ring. 
   With further reference to the alternate embodiment shown in  FIG. 6 , an exploded view is shown further in  FIG. 7 . In this embodiment, the handle body  202  is a separate member formed as an elliptical cylinder with an open top and bottom. As noted above, the bottom may be covered with an overriding case or by a cap. The topper  200  includes a base ring  222  and feature  202  that are constructed as described generally above with reference to  FIGS. 1-5 . In this embodiment, the toothbrush shaft  212  is formed as a separate member from either a single molded piece or a pair of shell halves. At the base of the toothbrush shaft  212  is formed a plug  224  having a smaller diameter than the main body of the shaft  212 . The plug is sized and arranged to fit within a socket hole  226  formed in the top of the base ring  222 . The plug and socket can be joined together permanently using a locking mechanism, adhesives, welding or any other acceptable joining technique. When joined together, the topper lip  214  seals against the outer wall of the main body of the shaft to prevent infiltration of water and to provide a secure friction fit of the shaft with respect to the topper. In an alternate embodiment, the shaft can be constructed in a manner that allows it to be slid out of the topper with associated components, such as the drive shaft. In this manner, a mechanism for enabling the shaft to be changed when the brush heads  228  is exhausted. A releasable locking mechanism or a simple friction fit can be used to secure the shaft in such an alternate embodiment. 
   With reference finally to  FIGS. 8 and 9 , two alternate techniques for joining the base ring of the topper assembly to a handle body are shown. These techniques are applicable to either of the embodiments described above. In  FIG. 8 , the handle body  300  includes a basic opening region  302 . The topper assembly  304  includes an inner securing wing  306  that bears against the inner wall of the handle body  300 . In addition, the outer skirt  310  of the base ring faces the outer wall of the handle body  300 . Adhesive  316  can be applied between the guide ring  306  and the inner wall, or at another location within the “sandwich” between the guide ring  306 , handle body  300  and skirt  310 . This adhesive can be sufficient to seal the structure against water infiltration. Additional sealing fixtures, such as O-rings (not shown) can also be provided. 
     FIG. 9  shows an alternate embodiment for securing the handle body  300  and topper assembly  404  together. In this embodiment, the side skirt  406  of the base ring  408  includes a pair of circumferential (or segmented) triangular indentations  410 . These indentations are sized and arranged to mate with corresponding triangular cross section formations  412  on the top end  414  of the body handle  400 . The orientation of the formations  412  and interlocking indentations  410  is such that when downward pressure (arrow  416 ) is applied to the base ring with respect to the body handle  400 , the skirt  406  deforms sufficiently to cause the indentations  410  and formations  412  to interlock. This firmly secures the base ring  408  to the body handle  400 . Additional sealing mechanisms such as an O-ring can also be provided between the top portion  414  of the body handle  400  and the base ring  408  to further enhance the seal therebetween. 
   The foregoing has been a detailed description of the illustrative embodiments of the invention. Various modifications and additions can be made without departing from the spirit and scope of this invention. For example, the materials used for various parts can be widely varied. The internal mechanism and/or number of brush heads used can vary. In addition, the movement pattern of the brush heads can be varied from the depicted rotational movement about rotational axes. Finally, it is contemplated that the size, shape and style of the topper feature as well as the shape of the handle can be widely varied from that depicted. In other words, large toppers having varied sizes can be employed and the handle can include non-cylindrical shapes including tapered shapes, sculpted shapes, rectangular-cross section shapes, and the like. Finally, while the topper and techniques described herein are directed generally toward a powered toothbrush, the topper can also be used in conjunction with a non-powered toothbrush having an appropriately sized and shaped handle. The teachings herein are expressly contemplated to include such brushes. Accordingly, this description is meant to be taken only by way of example and not to otherwise limit the scope of the invention. 
   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. 
   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.