CROSS-REFERENCE TO RLATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/506,933, filed on Jul. 12, 2011, the content of which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to refill heads for oral care implements, and specifically to the coupling structure of the refill head. 
       BACKGROUND OF THE INVENTION 
       [0003]    Powered toothbrushes having replaceable heads, commonly referred to as refill heads, are known in the art. Such powered toothbrushes typically include a handle and a refill head that is detachably coupled to the handle. The replaceability of the heads in such powered toothbrushes is desirous because the handle, which includes the expensive motion-inducing circuitry and components, is expensive to manufacture and has a much longer life expectancy than do the cleaning elements, such as bristles, that are on the head. Consumers would not be willing to pay a premium to purchase such powered toothbrushes if they had to be discarded when the bristles or other cleaning elements wore out. Thus, it is now standard in the industry to provide refill heads that can be attached and detached from the handle so that worn out refill heads can be replaced as needed for the same handle. 
         [0004]    Existing refill heads suffer from a number of deficiencies, including complexity of manufacture, the ability to improperly load the refill head to the handle, and inadequate coupling of the refill head to the handle. Thus, a need exist for a refill head having an improved coupling structure. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The present invention is directed to a refill head for an oral care implement, such as a toothbrush, wherein the refill head utilizes a specially designed structure for coupling the refill head to the oral care implement handle. The refill head comprises a tubular sleeve that forms a cavity and first and second upper cam surfaces that form shoulders within the cavity. 
         [0006]    The first and second upper cam surfaces are separated by first and second axial slots of different configurations. The configurations of the first and second axial slots prevent loading of the refill head onto the oral care implement handle in an improper rotational orientation through interaction with first and second bosses on the oral care implement handle. 
         [0007]    In one embodiment, the invention can be a toothbrush comprising: a handle comprising: a gripping portion; and a stem extending from the gripping portion, the stem extending along an axis; and first and second bosses extending radially from an outer surface of the stem, the first and second bosses arranged in a circumferentially spaced apart manner; and a refill head detachably coupled to the handle, the refill head comprising: a head portion comprising a plurality of tooth cleaning elements; a tubular sleeve coupled to the head portion, the tubular sleeve having a cavity in which the stem is disposed; and first and second upper cam surfaces that form transverse shoulders in the cavity, the first boss in surface contact with the first upper cam surface and the second boss in surface contact with the second upper cam surface to axially retain the stem within the cavity, the first and second upper cam surfaces circumferentially separated from one another by first and second axial slots, the first and second axial slots configured to: (1) allow the first boss to be axially slid through the first axial slot and the second boss to be axially slid through the second axial slot when the refill head is in a rotational orientation in which the first boss is axially aligned with the first axial slot and the second boss is axially aligned with the second axial slot; and (2) prohibit the second boss from being axially slid through the first axial slot when the refill head is in a rotational orientation in which the first boss is axially aligned with the second axial slot and the second boss is axially aligned with the first axial slot. 
         [0008]    In another embodiment, the invention can be a refill head for a toothbrush handle comprising a gripping portion and a stem having a first boss and a second boss, the refill head comprising: a head portion comprising a plurality of tooth cleaning elements; a tubular sleeve coupled to the head portion, the tubular sleeve having a cavity for slidably receiving the stem, the cavity extending along an axis; and first and second upper cam surfaces that form transverse shoulders in the cavity, the first and second upper cam surfaces circumferentially separated from one another by first and second axial slots, the first and second axial slots configured to: (1) allow the first boss to be axially slid through the first axial slot and the second boss to be axially slid through the second axial slot when the refill head is in a rotational orientation in which the first boss is axially aligned with the first axial slot and the second boss is axially aligned with the second axial slot; and (2) prohibit the second boss from being axially slid through the first axial slot when the refill head is in a rotational orientation in which the first boss is axially aligned with the second axial slot and the second boss is axially aligned with the first axial slot. 
         [0009]    In yet another embodiment, the invention can be a refill head for an oral care implement handle comprising a gripping portion and a stem having a first boss and a second boss, the refill head comprising: a head portion; a tubular sleeve coupled to the head portion, the tubular sleeve having a cavity for slidably receiving the stem, the cavity extending along an axis; first and second upper cam surfaces that form transverse shoulders in the cavity; and first and second axial slots, the first and second axial slots configured to: (1) allow the first boss to be axially slid through the first axial slot and the second boss to be axially slid through the second axial slot when the refill head is in a rotational orientation in which the first boss is axially aligned with the first axial slot and the second boss is axially aligned with the second axial slot; and (2) prohibit the second boss from being axially slid through the first axial slot when the refill head is in a rotational orientation in which the first boss is axially aligned with the second axial slot and the second boss is axially aligned with the first axial slot. 
         [0010]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0012]      FIG. 1  is a front view of a refill head and a toothbrush handle in alignment for detachable coupling according to one embodiment of the present invention, the wherein the refill head is in cross-section and the handle is in partial cut-away; 
           [0013]      FIG. 2  is a longitudinal cross-sectional view of the refill head according to one embodiment of the present invention; 
           [0014]      FIG. 3  is a left-side view of a stem of the toothbrush handle of  FIG. 1  according to one embodiment of the present invention; 
           [0015]      FIG. 4  is a right-side view of a stem of the toothbrush handle of  FIG. 1  according to one embodiment of the present invention; 
           [0016]      FIG. 5  is a front view of the refill head and the toothbrush handle of  FIG. 1  detachably coupled together according to one embodiment of the present invention; 
           [0017]      FIG. 6  is a linear map of the first and second cams of the refill head according to one embodiment of the present invention; and 
           [0018]      FIG. 7  is bottom view of the refill head of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0020]    The description of illustrative embodiments according to principles of the present invention is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description of embodiments of the invention disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivative thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation unless explicitly indicated as such. Terms such as “attached,” “affixed,” “connected,” “coupled,” “interconnected,” and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. Moreover, the features and benefits of the invention are illustrated by reference to the exemplified embodiments. Accordingly, the invention expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto. 
         [0021]    Referring to  FIGS. 1 and 5  concurrently, a powered toothbrush  1000  according to one embodiment of the present invention is illustrated. The powered toothbrush  1000  generally comprises a refill head  100  and a handle  200 . As discussed in greater detail below, the refill head  100  and the handle  200  are designed so that the refill head  100  can be repetitively coupled and uncoupled from the handle  200 . In  FIG. 1 , the powered toothbrush  1000  is illustrated in a state wherein the refill head  100  is not coupled to the handle  200  but is positioned an axial alignment with the handle  200  so that such coupling can be effectuated. In  FIG. 5 , the powered toothbrush  1000  is illustrated in a state wherein the refill head  100  is detachably coupled to the handle  200  according to an embodiment of the present invention. 
         [0022]    While the invention is exemplified herein as a powered toothbrush  1000 , it is to be understood that the inventive concepts discussed herein can be applied to manual toothbrushes that utilize refill heads, or other manual or powered oral care implements, including without limitation tongue cleaners, water picks, interdental devices, tooth polishers and specially designed ansate implements having tooth engaging elements. 
         [0023]    Referring now to  FIGS. 1 ,  3  and  4  concurrently, the handle  200  will be described in greater detail. The handle  200  generally comprises a gripping portion  210  (only a small portion of which is exemplified) and a stem  220 . The stem  220  extends from the gripping portion  210  along a longitudinal axis A-A. 
         [0024]    The gripping portion  210  of the handle  200  is an elongated structure that provides the mechanism by which the user can hold and manipulate the powered toothbrush  1000  during use. The gripping portion  210  can take on a wide variety shapes, contours and configurations, none of which are limiting of the present invention. Included within the gripping portion  210  is a power source, an electric motor and electrical circuitry and components necessary to create a desired motion within the refill head  100 . 
         [0025]    The gripping portion  210  also includes the user interface that controls the various operations of the toothbrush  1000 , including without limitation turning off and on, changing speeds of the motor, or other included functions. The gripping portion  210 , in essence, forms a watertight housing for the aforementioned electrical circuit and mechanical components that need to be protected from moisture. 
         [0026]    In the exemplified embodiment, the motion to be transmitted to the head portion  110  of the refill head  100  is a vibratory motion. In order to generate such vibratory motion, the handle  200  comprises a vibratory element, which in the exemplified embodiment is in the form of an eccentric  222  coupled to a drive shaft  221 . A proximal portion (not illustrated) of the drive shaft  221  is operably coupled to the electric motor (not illustrated) so that the electric motor can rotate the drive shaft  221 . A distal portion  223  of the drive shaft  221  is retained by an annular bearing  224  which is mounted within the stem  220 . As the drive shaft  221  is rotated, the eccentric  222 , due to its off-center center of gravity, generates vibrations that are transmitted to the stem  220  and to the refill head  100  (discussed in greater detail below). While the eccentric  222  is exemplified as a portion of the drive shaft  221  that is radially offset from the longitudinal axis A-A, the invention is not so limited. In other embodiments, the eccentric  222  may be an offset disc or other offset weight, as is known in the art. As can be seen in  FIG. 1 , the stem  220  forms a watertight housing having an internal cavity  225  in which the drive shaft  221  and eccentric  222  are housed. Additional details of a suitable vibratory producing handle, and related structure that can be incorporated into the powered toothbrush  1000  of the present invention, can be found in U.S. Patent Application Publication No. 2010/0269275, Shimoyama et al., published Oct. 28, 2010 (filed as U.S. patent application Ser. No. 12/377,355), the entirety of which is hereby incorporated by reference. 
         [0027]    The stem  220  comprises a proximal portion  226 , a middle portion  227  and a distal portion  228 . The proximal portion  226  is the base portion of the stem  220  that is adjacent the gripping portion  210  of the handle  200 . The distal portion  228  forms the free end of the stem  220  while the middle portion is located axially between the proximal portion  226  and the distal portion  228 . 
         [0028]    The stem  220  further comprises a first boss  229  and a second boss  230  extending radially outward from an outer surface  231  of the stem  220 . The first and second bosses  229 ,  230  are arranged on the stem  220  in a circumferentially spaced apart manner. In the exemplified embodiment, the first and second bosses  229 ,  230  are approximately 180° apart. Of course, other angular degrees of separation can be utilized as desired. Moreover, in alternate embodiments, more or less than two bosses  229 ,  230  can be included on the stem  220 . 
         [0029]    As will be discussed in greater detail below, the first and second bosses  229 ,  230  have different configurations from one another so as to achieve the desired cooperation (or lack thereof) with the axial slots  151 ,  152  of the cam collar  150 . In the exemplified embodiment, the different configuration of the first and second bosses  229 ,  230  is achieved by creating the first and second bosses  229 ,  230  to have different sizes. As exemplified, the first boss  229  has a first diameter D 1  while the second boss  230  has a second diameter D 2 , wherein the second diameter D 2  is greater than the first diameter D 1 . In the exemplified embodiment, both the first and second bosses  229 ,  230  are cylindrical pin-like elements. However, in alternate embodiments, the first and second bosses  229 ,  230  can have other cross-sectional shapes, including polygonal, oval, or irregular shaped. Thus, as used herein the term “diameter” is not strictly limited to circular geometries. 
         [0030]    In alternate embodiments, the desired cooperation (or lack thereof) between the axial slots  151 ,  152  of the cam collar  150  and the first and second bosses  229 ,  230  of the stem  220  can be achieved by appropriately designing the shapes of the axial slots  151 ,  152  of the cam collar  150  and the first and second bosses  229 ,  230  of the stem  220  (this concept will become more clear from the discussion below). Thus, in one alternate embodiment, the first boss  229  will have a first shape and the second boss  230  will have a second shape that is different than the first shape. The first shape is selected so that the first boss  229  can be axially slid through the first axial slot  151  when axially aligned therewith while the second shape cannot be axially slid through the first axial slot  151  when axially aligned therewith. 
         [0031]    The distal portion  228  of the stem  220  further comprises a plug portion  231  extending axially from a shoulder portion  232 . The plug portion  231  acts as an axial alignment feature by sliding into a distal axial section  126  of the cavity  182  of the refill head  100  when the refill head  100  is being coupled to the stem  220 /handle  200 . The shoulder portion  232  can be used to prevent over-insertion of the stem  220  into the cavity  182  during said coupling via contact with an annular shoulder  128  formed in the inner surface  181  of the refill head  100 . 
         [0032]    Referring now to FIGS.  2  and  6 - 7  concurrently, the structure of the refill head  100  will be described in greater detail. The refill head  100  generally comprises a head portion  110 , a tubular sleeve  120  and an annular cam collar  150 . 
         [0033]    The tubular sleeve  120 , the head portion  110  and the cam collar  150  can be formed of a material that is rigid, such as a moldable hard plastic. Suitable hard plastics include polymers and copolymers of ethylene, propylene, butadiene, vinyl compounds and polyesters such as polyethylene terephthalate. Of course, the invention is not to be so limited and other materials can be used to form the tubular sleeve  120  and head portion  110  of the refill head  100 . 
         [0034]    The tubular sleeve  120  extends along a longitudinal axis B-B from a proximal end  121  to a distal end  22 . The head portion  110  is coupled to the distal end  121  of the tubular sleeve  120 . In the exemplified embodiment, the tubular sleeve  120  and the head portion  110  of the refill head  100  are integrally formed as a single unitary structure using a molding, milling, machining or other suitable process. However, in other embodiments the head portion  110  and the tubular sleeve  120  of the refill head  100  may be formed as separate components which are operably connected at a later stage of the manufacturing process by any suitable technique known in the art, including without limitation thermal or ultrasonic welding, a tight-fit assembly, a coupling sleeve, threaded engagement, adhesion, or fasteners. 
         [0035]    While not illustrated, the head portion  110  comprises a plurality of tooth cleaning elements extending from a surface thereof as is known in the art. The plurality of tooth cleaning elements are provided for cleaning and/or polishing an oral surface and/or interdental spaces. The tooth cleaning elements can be particularly suited for brushing teeth, or can be particularly suited to polish teeth instead of or in addition to cleaning teeth. As used herein, the term “tooth cleaning elements” is used in a generic sense to refer to any structure that can be used to clean, polish or wipe the teeth and/or soft oral tissue (e.g. tongue, cheek, gums, etc.) through relative surface contact. Common examples of “tooth cleaning elements” include, without limitation, bristle tufts, filament bristles, fiber bristles, nylon bristles, spiral bristles, rubber bristles, elastomeric protrusions, flexible polymer protrusions, combinations thereof and/or structures containing such materials or combinations. Suitable elastomeric materials include any biocompatible resilient material suitable for uses in an oral hygiene apparatus. To provide optimum comfort as well as cleaning benefits, the elastomeric material of the tooth or soft tissue engaging elements has a hardness property in the range of A8 to A25 Shore hardness. One suitable elastomeric material is styrene-ethylene/butylene-styrene block copolymer (SEBS) manufactured by GLS Corporation. Nevertheless, SEBS material from other manufacturers or other materials within and outside the noted hardness range could be used. 
         [0036]    The tooth cleaning elements of the present invention can be connected to the refill head  100  in any manner known in the art. For example, staples/anchors, in-mold tufting (IMT) or anchor free tufting (AFT) could be used to mount the cleaning elements/tooth engaging elements. In AFT, a plate or membrane is secured to the brush head such as by ultrasonic welding. The bristles extend through the plate or membrane. The free ends of the bristles on one side of the plate or membrane perform the cleaning function. The ends of the bristles on the other side of the plate or membrane are melted together by heat to be anchored in place. Any suitable form of cleaning elements may be used in the broad practice of this invention. Alternatively, the bristles could be mounted to tuft blocks or sections by extending through suitable openings in the tuft blocks so that the base of the bristles is mounted within or below the tuft block. 
         [0037]    The tubular sleeve  120  comprises an inner surface  181  that forms an internal cavity  182  that extends along the longitudinal axis B-B. The internal cavity  182  is sized and shaped to accommodate the stem  220  of the handle  200  so that the refill head  100  can be detachably coupled to the handle  200  as described below. The tubular sleeve  120  further comprises an opening  123  at the proximal end  121  that provides a passageway into the cavity  182  so that the stem  220  can be axially translated into and out of the cavity  182  via the opening  123 . 
         [0038]    The cavity  182  comprises a proximal axial section  124 , a middle axial section  125 , and a distal axial section  126 . The proximal axial section  124  extends from the opening  123  to a first shoulder  127  formed in the inner surface  181 . The proximal axial section  124  has a substantially constant transverse cross-sectional area. The middle axial section  125  extends from the first shoulder  127  to a second shoulder  128  formed in the inner surface  181 . The middle axial section  125  has a tapered transverse cross-sectional area along its length moving from the first shoulder  127  to the second shoulder  128 . The distal axial section  126  extends from the second annular shoulder  128  to an end wall  129 . The distal axial section  126  has a reduced cross-sectional area in comparison to the middle axial section  126 , even at the middle axial section&#39;s  125  smallest transverse cross-sectional area. 
         [0039]    As mentioned above, the refill head  100  further comprises a cam collar  150 . The cam collar  150  is disposed within the cavity  182  and coupled to the tubular sleeve  120 . More specifically, the cam collar  150  is disposed within the proximal axial section  124  of the internal cavity  182 . The cam collar  150  is coupled to the tubular sleeve  120  so as to be non-rotatable with respect to the tubular sleeve  120 . In the exemplified embodiment, the axial position of the cam collar  150  within the cavity  182  of the tubular sleeve  120  is achieved by a combination of contact with the first annular shoulder  127  and an annular retaining flange  130  that protrudes radially inward from the inner surface  181 . Thus, the first annular shoulder  127  prevents axial movement of the cam collar  150  relative to the tubular sleeve  120  in a first axial direction while the annular retaining flange  130  prevents axial movement of the cam collar  150  relative to the tubular sleeve  120  in a second axial direction (opposite the first axial direction). Rotational movement between the cam collar  150  and the tubular sleeve  120  is prohibited by interlock tabs  153  of the cam collar  150  that extend into axially extending slots  131  formed into the first annular shoulder  127  of the inner surface  181  of the tubular sleeve  120 . 
         [0040]    In the exemplified embodiment, the cam collar comprises an annular outer wall  154  and a first inner step  155  and a second inner step  156 . The first inner step  155  comprises a first upper cam surface  157  while the second inner step  156  comprises a second upper cam surface  158 . The first and second upper cam surfaces  157 ,  158  form transverse shoulders in the cavity  182 . When the powered toothbrush  1000  is properly assembled and the refill head  100  is detachably coupled to the handle  200 , the first boss  229  of the stem  120  is in surface contact with the first upper cam surface  157  and the second boss  230  in surface contact with the second upper cam surface  158  (as shown in  FIG. 6 ) to axially retain the stem  220  within the cavity  182  to maintain the detachable coupling. 
         [0041]    The first and second steps  155 ,  156 , and thus the first and second upper cam surfaces  157 ,  158 , are circumferentially separated from one another by first and second axial slots  151 ,  152 . The first upper cam surface  157  comprises a first depression  159  in which the first boss  229  nests when the refill head  100  is detachably coupled to the handle  200 . Similarly, the second upper cam surface  158  comprises a second depression  160  in which the second boss  230  nests when the refill head  100  is detachably coupled to the handle  200 . 
         [0042]    The first upper cam surface  157  also comprises a first ramp portion  161  and a first stopper portion  162 . The first ramp portion  161  extends from the first axial slot  151  to the first depression  159  and is configured to allow the first boss  229  to ride along the first upper cam surface  157  from the first axial slot  151  and the first depression  159 . On the other hand, the first stopper portion  162  is located between the first depression  159  and the second axial slot  152  and is configured to prohibit the first boss  229  from being rotated from the first depression  129  into axial alignment with the second axial slot  152 . Similarly, the second upper cam surface  158  comprises a second ramp portion  163  and a second stopper portion  164 . The second ramp portion  163  extends from the second axial slot  152  to the second depression  160  and is configured to allow the second boss  230  to ride along the second upper cam surface  158  from the second axial slot  152  to the second depression  160 . To the contrary, the second stopper portion  164  is located between the second depression  160  and the first axial slot  151  and is configured to prohibit the second boss  230  from being rotated from the second depression  160  into axial alignment with the first axial slot  151 . 
         [0043]    Referring now to  FIGS. 3-5  and  7  concurrently, the first and second axial slots  151 ,  152  are configured to: (1) allow the first boss  229  to be axially slid through the first axial slot  151  and the second boss  230  to be axially slid through the second axial slot  152  when the refill head  200  is in a rotational orientation in which the first boss  229  is axially aligned with the first axial slot  151  and the second boss  230  is axially aligned with the second axial slot  152 ; and (2) prohibit the second boss  230  from being axially slid through the first axial slot  151  when the refill head  200  is in a rotational orientation in which the first boss  229  is axially aligned with the second axial slot  152  and the second boss  230  is axially aligned with the first axial slot  151 . 
         [0044]    In the exemplified embodiment, the second boss  230  is prohibited from being axially slid through the first axial slot  151  due to the second boss  230  being too large. Specifically, the first axial slot has a first width W 1  and the second axial slot  152  has a second width W 2 . The first width W 1  is greater than or equal to the first diameter D 1  and less than the second diameter D 2 . The second width W 2 , on the other hand, is greater than or equal to the second diameter D 2  (and thus also greater than the first diameter D 1 ). As a result, the second boss  230  can be axially translated through the second axial slot  152  but is too large to be axially translated through the first axial slot  151 . Thus, in order for the stem  220  of the handle  200  to be inserted into the cavity  182  of the refill head  200 , the refill head must be put in a rotational orientation in which the which the first boss  229  is axially aligned with the first axial slot  151  and the second boss  230  is axially aligned with the second axial slot  152 . Once this rotational orientation is achieved, the stem  220  is inserted into the cavity  182  until the first and second bosses  229 ,  230  pass through the first and second axial slots  151 ,  152  respectively. Once the first and second bosses  229 ,  230  have passed through the first and second axial slots  151 ,  152 , the refill head  200  is rotated (clockwise 90 degrees) relative to the handle  200  so that the first and second bosses  229 ,  230  ride along the ramp portions  161 ,  163  of the first and second upper cam surfaces  157 ,  158  until they nest in the first and second depressions  159 ,  160  respectively. As the first and second bosses  229 ,  230  ride up the ramp portions  161 ,  163 , the fit between the first and second bosses  229 ,  230  and the first and second upper cam surfaces  157 ,  158  is tightened. The first and second bosses  229 ,  230  then fall into the first and second depressions  159 ,  160 , achieving a more relaxed state between the first and second bosses  229 ,  230  and the first and second upper cam surfaces  157 ,  158 . The first and second depressions  159 ,  160  retain the first and second bosses  229 ,  230  in contact with the first and second upper cam surfaces  157 ,  158 . This mating can be further enhanced by the incorporation of a resilient gasket that provides an axial force that further forces the first and second bosses  229 ,  230  into the first and second depressions  159 ,  160  (not illustrated). The stopper portions  162 ,  164  prevent over rotation. 
         [0045]    When a user wants to remove the refill head  100  from the handle  200 , the user rotates the refill head  100  relative to the handle  200  in the opposite rotational direction (i.e., counterclockwise 90 degrees) until the first and second bosses  229 ,  230  are forced from the first and second depressions  159 ,  160  and slide down the ramp portions  161 ,  163  of the first and second upper cam surfaces  157 ,  158 . This rotation continues until the first and second bosses  229 ,  230  come back into axial alignment with the first and second axial slots  151 ,  52  respectively. At this time, the stem  220  can be axially withdrawn from the cavity  182  of the refill head  100 . 
         [0046]    Furthermore, when the refill head  100  is detachably coupled to the handle  200  as described above, the first and second supper cam surfaces  157 ,  158  are located within the proximal axial section  124  of the cavity  182 . Moreover, only the outer surface of the distal portion  228  of the stem  220  is in intimate surface contact with the inner surface  181  of the tubular sleeve  120 . Thus, vibrations generated by the eccentric  223  in the stem  220  are more effectively transmitted to the head portion  210  of the refill head  200 . It is may be advantageous to minimize vibration below the distal portion  228  so that vibration is not transmitted to the handle  200 . 
         [0047]    The first and second bosses  229 ,  230  are integrally molded to the stem  220  in the exemplified embodiment. Further, while the first and second upper cam surfaces  157 ,  158  are located on the cam collar  150  in the exemplified embodiment, the first and second upper cam surfaces  157 ,  158  could be formed integrally into the tubular sleeve  120 . 
         [0048]    As used throughout, ranges are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. In addition, all references cited herein are hereby incorporated by referenced in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls. 
         [0049]    While the foregoing description and drawings represent the exemplary embodiments of the present invention, it will be understood that various additions, modifications and substitutions may be made therein without departing from the spirit and scope of the present invention as defined in the accompanying claims. In particular, it will be clear to those skilled in the art that the present invention may be embodied in other specific forms, structures, arrangements, proportions, sizes, and with other elements, materials, and components, without departing from the spirit or essential characteristics thereof. One skilled in the art will appreciate that the invention may be used with many modifications of structure, arrangement, proportions, sizes, materials, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims, and not limited to the foregoing description or embodiments.
A refill head for an oral care implement, such as a toothbrush, wherein the refill head utilizes a specially designed structure for coupling the refill head to an oral care implement handle that ensures proper alignment and simplifies the loading and unloading of the refill head to the oral care implement handle. In one embodiment, the refill head comprises a tubular sleeve forming a cavity and first and second upper cam surfaces that form shoulders within the cavity. The first and second upper cam surfaces are separated by first and second axial slots of different configurations that prevent loading of the refill head onto the oral care implement handle in an improper rotational orientation through interaction with first and second bosses on the oral care implement handle.