Patent Publication Number: US-2020289246-A1

Title: Oral care implement and handle and refill head thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 15/838,796, filed Dec. 12, 2017, the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Myriad implements and devices for maintaining oral health are known. For example, toothbrushes of both the manual and powered variety, floss, dentifrices, applicators, agents, and the like are all known to provide different benefits in the oral cavity. For oral care implements that include a handle and one or more replaceable oral care devices that can be repetitively coupled to and detached from the handle, there is a need to design a coupling or locking mechanism to ensure that the replaceable oral care device remains securely coupled to the handle during use. Furthermore, devices of this type may also include alignment features to ensure that the replaceable oral care device and handle are acceptably aligned during coupling. There remains a need for improvement in all of the aforementioned areas with regard to oral care implements including a need for a proprietary oral care implement handle to refill head connection mechanism. 
     BRIEF SUMMARY 
     The present invention is directed to an oral care implement handle or a refill head therefor. The oral care implement handle may include a gripping portion and a stem protruding from a shoulder of the gripping portion. The stem may include a post located at a distal end of the stem. The post may have a non-circular transverse profile. More specifically, the post may include a hub portion and a protuberance. The protuberance may protrude radially from a side surface of the hub portion, upward from the shoulder of the gripping portion, or both. The refill head may include a sleeve having an inner surface that defines an internal cavity for receiving the stem of the handle. The internal cavity may include a distal section having a central portion and at least one slot portion extending radially from the central portion. Thus, the internal cavity of the sleeve portion may have a profile configured to receive the stem of the oral care implement handle including the non-circular post thereof. 
     In one aspect, the invention may be an oral care implement handle comprising: a gripping portion extending from a proximal end to a distal end; a stem comprising an attachment portion protruding from a first transverse shoulder at the distal end of the gripping portion, the stem extending along a stem axis and configured to be detachably coupled to a replaceable oral care device, the attachment portion of the stem comprising: a second transverse shoulder axially spaced from the first transverse shoulder; and a post protruding from the second transverse shoulder, the post terminating in a closed distal end that forms a free end of the attachment portion of the stem, the post comprising a hub portion extending along the stem axis and at least one protuberance protruding either (1) radially from a side surface of the hub portion; and/or (2) upward from the second transverse shoulder; and a vibration generating device. 
     In another aspect, the invention may be an oral care implement handle comprising: a gripping portion extending from a proximal end to a distal end; a stem comprising an attachment portion protruding from the distal end of the gripping portion, the stem extending along a stem axis and configured to be detachably coupled to a replaceable oral care device, the attachment portion of the stem comprising a post terminating in a closed distal end that forms a free end of the attachment portion of the stem, the closed distal end of the post having a non-circular transverse profile. 
     In yet another aspect, the invention may be an oral care refill head comprising: a sleeve portion extending from a proximal end to a distal end, the sleeve portion comprising: an inner surface that defines an internal cavity; the internal cavity extending along a sleeve axis from an open bottom end at the proximal end of the sleeve portion and a closed top end, the internal cavity configured to receive an attachment portion of a stem of an oral care implement handle; the internal cavity comprising a proximal section adjacent the open bottom end and a distal section adjacent the closed top end; and the distal section of the internal cavity comprising a central portion located on the sleeve axis and at least one slot portion radially extending from the central portion. 
     In still another aspect, the invention may be an oral care refill head comprising: a sleeve portion extending from a proximal end to a distal end, the sleeve portion comprising: an inner surface that defines an internal cavity that extends along an axis, the internal cavity configured to receive an attachment portion of a stem of an oral care implement handle; and wherein a transverse cross-section of the internal cavity comprises a central portion and a plurality of slot portions radially extending from the central portion, the plurality of slot portions being circumferentially equi-spaced from one another. 
     In a further aspect, the inventio may be an oral care implement comprising: a handle comprising: a gripping portion extending from a proximal end to a distal end, the distal end of the gripping portion forming a first transverse shoulder; a stem extending along a stem axis and comprising an attachment portion protruding from the first transverse shoulder that houses a vibration generating device, the attachment portion comprising: a second transverse shoulder axially spaced from the first transverse shoulder; and a post protruding from the second transverse shoulder, the post terminating in a closed distal end that forms a free end of the attachment portion of the stem, the post comprising a hub portion extending along the stem axis and at least one protuberance protruding either (1) radially from a side surface of the hub portion; and/or (2) upward from the second transverse shoulder, the at least one protuberance terminating in a side terminal surface; a refill head comprising: a sleeve portion extending from a proximal end to a distal end, the sleeve portion comprising an inner surface that defines an internal cavity; and 
     wherein the refill head is detachably coupled to the stem of the handle such that the attachment portion of the handle is located within the internal cavity of the sleeve portion of the refill head and the side terminal surface of the at least one protuberance is in surface contact with the inner surface of the sleeve portion. 
     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 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a front perspective view of an oral care implement having a refill head and a handle in accordance with an embodiment of the present invention; 
         FIG. 2  is a front perspective view of the oral care implement of  FIG. 1  illustrating the refill head detached from a handle; 
         FIG. 3  is an exploded front perspective view of the oral care implement of  FIG. 1 ; 
         FIG. 4  if a front view of a stem of the handle of the oral care implement of  FIG. 1 ; 
         FIG. 5  is a top view of the stem of  FIG. 4 ; 
         FIG. 6  is a front view of the refill head of  FIG. 1 ; 
         FIG. 7  is a cross-sectional view taken along line VII-VII of  FIG. 6 ; 
         FIG. 8  is a cross-sectional view taken along line VIII-VIII of  FIG. 6 ; 
         FIG. 9  is a cross-sectional view taken along line IX-IX of  FIG. 1 ; 
         FIG. 10  is a cross-sectional view taken along line X-X of  FIG. 1 ; and 
         FIG. 11  is a cross-sectional view taken along line X-X of  FIG. 1  in accordance with an alternative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     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 derivatives 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. 
     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 reference 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. 
     Referring to  FIGS. 1-3  concurrently, an oral care implement  1000  is illustrated in accordance with an embodiment of the present invention. The oral care implement  1000  generally comprises a handle  100  and a refill head  200 . The refill head  200  is detachably coupled to the handle  100 . Thus, the refill head  200  may be repetitively coupled to and detached from the handle  100  as desired. This enables the handle  100  to be kept and reused while the refill head  200  is replaced with a new refill head when the cleaning elements of the refill head  200  become worn. This is desirable because often the handle contains or otherwise houses the expensive electronic components of an oral care implement and the handle usually long outlasts the tooth cleaning elements. Thus, by permitting the refill head  200  to be detached from the handle  100  and replaced with another refill head, the same handle can be used with different refill heads  200 , thereby prolonging the life of the oral care implement  1000 . 
     In the exemplified embodiment, the oral care implement  1000  is a powered or electric toothbrush (including a vibration generating device that moves a bristle holder or vibrates the head or portions thereof). Of course, the invention is not to be so limited in all embodiments and in other embodiments the oral care implement  1000  may be a manual toothbrush, a tongue scraper, a gum and soft tissue cleanser, a water pick, an interdental device, a tooth polisher, a specially designed ansate implement having tooth engaging elements, or any other type of implement that is commonly used for oral care. 
     The handle  100  extends along a longitudinal axis A-A and comprises a gripping portion  110  extending from a proximal end  111  to a distal end  112  and a stem  120  that extends or protrudes from the distal end  112  of the gripping portion  111 . The distal end  112  of the gripping portion  110  forms a first transverse shoulder  114  of the stem  120 . In the exemplified embodiment, the stem  120  is not directly attached to the gripping portion  110 , but rather it extends through an opening  139  in the distal end  112  of the gripping portion  111 . Thus, stating that the stem  120  extends from the distal end  112  of the gripping portion  111  does not require a direct coupling between the stem  120  and the distal end  112  of the gripping portion  111 , but merely requires that the stem  120  extends in the longitudinal direction A-A beyond the distal end  112  of the gripping portion  110 . Of course, the stem  120  may be directly coupled to and extend directly from the distal end  112  of the gripping portion  110  in some embodiments. The first transverse shoulder  114  circumferentially surrounds the stem  120  as it protrudes form the distal end  112  of the gripping portion  110 . 
     In the exemplified embodiment, the gripping portion  110  of the handle  100  comprises an actuator  113  on its outer surface that enables a user to power the oral care implement  1000  on and off. In the exemplified embodiment, the actuator  113  is located on a front surface of the gripping portion  110  of the handle  100 . The actuator  113 , when depressed, engages a switch that powers a motor  160  of the oral care implement  1000  and causes the motor  160 , via its coupling to an eccentric  161 , to create vibrations that enhance a user&#39;s cleaning experience. Thus, the actuator  113  is configured to activate and deactivate a vibration generating device  199  (which may comprise the motor  160 , the eccentric  161 , and a power source) that is housed within the handle  100 , as described more fully below. The details of these electronic components will be described more fully herein below. 
     The refill head  200  comprises a sleeve portion  210  and a head portion  220 . The sleeve portion  210  is the portion that fits over the stem  120  of the handle  100  to couple the refill head  200  to the handle  100 . The head portion  220  has a plurality of tooth cleaning elements  215  extending therefrom for cleaning a user&#39;s oral cavity such as the teeth and gums. Additional details of the refill head  200  will be provided below with reference to  FIGS. 6-8 . 
     In the exemplified embodiment, the gripping portion  110  of the handle  100  comprises a first part  130  and a second part  131  that are detachably coupled together. The first and second parts  130 ,  131  may be detachably coupled together via mating screw threads, interference fit, boss/detent, or the like. Of course, it is possible in other embodiments for the gripping portion  110  to be formed from a single unitary component. However, the two-part gripping portion  110  may make it easier to assemble the various components of the oral care implement  1000  together. When coupled together, the first and second parts  130 ,  131  collectively define a handle cavity  134 . An  0 -ring  138  (or other type of gasket) may be provided between the first and second parts  130 ,  131  of the gripping portion  110  to seal the interface of the first and second parts  130 ,  131  so that water and other fluids cannot pass into the handle cavity  134  during use of the oral care implement  1000  or otherwise. 
     An electronics component  150  is housed within the handle cavity  134 . The electronics component  150  comprises a circuit board  155  comprising the electronic circuitry necessary for proper operation of the oral care implement  1000 , including processor(s), memory device(s), switch(es)  157 , resistors, capacitors, and the like. The electronics component  150  also comprises a chassis  156  that holds a power source  151 , which is shown as a battery exploded away from the electronics component  150  in  FIG. 3 . Of course, more than one battery may be used. In the exemplified embodiment, the circuit board  155  is coupled to one side of the chassis  156  and the batteries are housed within a compartment located on the opposite side of the chassis  156 . Of course, other arrangements are possible in other embodiments. Generally, the electronics component  150  is configured to be coupled to the motor  160  to control operation of the motor  160  such that when the switch  157  is on the motor  160  is operating and when the switch  57  is off the motor  160  is not operating. On/off of the switch  157  may be controlled via actuation of the actuator  113 . 
     A gasket  165  is provided at the junction of the stem  120  and the gripping portion  110  to prevent the ingress of liquids at the location of the junction of those two components. The gasket  165  is coupled to the stem  120  so as to surround a lower portion  121  of the stem  120 . Furthermore, the gasket  165  presses against the inner surface of the second component  131  of the gripping portion  110  to maintain the stem  120  in position without the stem  120  falling into the handle cavity  134 . A portion of the gasket  165  may be visible when the handle  100  is fully assembled with the refill head  200  detached therefrom, as best illustrated in  FIG. 2 . The interaction of the gasket  165  with the stem  120  and the gripping portion  110  is best shown in  FIG. 9 . A second gasket  178  may be coupled to another portion of the lower portion  121  of the stem  120  and collectively the gasket  165  and the second gasket  178  operate to prevent the ingress of fluids. Of course, one or both of the gasket  165  and the second gasket  178  may be omitted in alternative embodiments. 
     Referring to  FIGS. 3 and 9 , the stem  120  comprises an inner surface  123  that defines an inner cavity  122  that houses the motor  160 , the eccentric  161 , a coupling member  162  that couples the motor  160  to the eccentric  161 , and a shaft  190 . The motor  160 , the eccentric  161 , and the power source  151  (or various other combinations of the components housed within the stem  120 ) may be referred to herein collectively as the vibration generating device  199  because these components are coupled together and operate collectively to impart vibrations to the head portion  220  and the tooth cleaning elements  215  of the refill head  200 . The motor  160  is electrically coupled to the electronics component  150  and the power source  151  via conductive wires  163  to control operation of the motor  160 . When the motor  160  is activated, the eccentric  161  is caused to rotate due to its coupling to the motor  160 . Due to the off-center rotation of the eccentric  161  relative to a central axis of the motor  160 , rotation of the eccentric  161  imparts vibrations to the head portion  220  of the refill head  200 . 
     Referring to  FIGS. 2, 4, 5, and 9  concurrently, the stem  120  of the handle  100  will be further described. The stem  120  extends along a stem axis B-B and is configured to be detachably coupled to the refill head  200  (or, more generically, to a replaceable oral care device as it need not be limited to being configured for coupling to the refill head  200  described herein specifically). Thus, the stem  120  can in actuality be coupled to any replaceable oral care device that is capable of receiving the stem  120  therein and being locked thereto, at least in a temporary sense, such that the oral care device remains coupled to the stem  120  during use of the oral care implement  1000 . 
     The stem  120  comprises the lower portion  121  and an attachment portion  140 . When the handle  100  is fully assembled, the lower portion  121  of the stem  120  is located within the cavity  134  of the gripping portion  110  and the attachment portion  140  of the stem  120  protrudes from the first transverse shoulder  114  at the distal end  112  of the gripping portion  110 . As described more fully below, the refill head  200  receives the attachment portion  140  of the stem  120  when coupled thereto. As seen in  FIG. 9 , a portion of the lower portion  121  of the stem  120  is surrounded by the gasket  165  and the gasket  165  terminates at the first transverse shoulder  114  whereas the attachment portion  140  of the stem  120  extends beyond the first transverse shoulder  114 . 
     The attachment portion  140  of the stem  120  comprises a base portion  141  and a post  142 . The base portion  141  protrudes from the first transverse shoulder  114  and terminates in a distal surface  143  that forms a second transverse shoulder  144  of the stem  120 . The second transverse shoulder  144 , which is formed by the distal end  143  of the base portion  141  of the attachment portion  140  of the stem  120 , is axially spaced apart from the first transverse shoulder  114 , which is formed by the distal end  112  of the gripping portion  110  of the handle  100 . The post  142  protrudes from the second transverse shoulder  144  and terminates in a closed distal end  145  that forms a free end of the attachment portion  140  of the stem  120 . In the exemplified embodiment, the closed distal end  145  of the post  142  comprises a depression  149  that is located on or aligned with the stem axis B-B. 
     In the exemplified embodiment, the stem  120  is an integrally formed structure that includes the lower portion  121  and the attachment portion  140  (with the attachment portion  140  comprising the base portion  141  and the post  142 ). Thus, the stem  120  may be a monolithic component formed from a rigid material, such as plastic or the like. In some embodiments the stem  120  is formed via injection molding, although this manufacturing technique is not required in all embodiments. 
     The base portion  141  comprises a locking feature  146  configured to mate with a locking feature of the refill head  200 . In the exemplified embodiment, the locking feature  146  is a protuberance or boss that protrudes from an outer surface  147  of the base portion  141  and it is received within a recess, notch, or slot of the refill head  200 . Furthermore, in the exemplified embodiment the base portion  141  also comprises one or more alignment protuberances  148  protruding from the outer surface  147  of the base portion  141 . The size, shape, structure, depth, thickness, length, or the like of the locking feature  146  and/or the alignment protuberances  148  are not intended to be limiting of the present invention in all embodiments. Thus, various locking features  146  and alignment protuberances  148  may be used on the base portion  141  to ensure proper alignment between the refill head  200  and the handle  100  and to facilitate locking of the refill head  200  to the handle  100 . 
     As noted above, the post  142  protrudes from the second transverse shoulder  144  at the distal end  143  of the base portion  141  of the stem  120  and terminates at the closed distal end  145 . The post  142  has a smaller diameter (or maximum width measured transverse to the stem axis B-B) than the second transverse shoulder  144 , and thus a portion of the second transverse shoulder  144  is exposed between an outermost surface/edge of the post  142  and an outer edge  177  of the second transverse shoulder  144 . As best seen in  FIG. 5 , in the exemplified embodiment the closed distal end  145  of the post  142  of the stem  120  has a non-circular transverse profile. More specifically, in the exemplified embodiment the transverse profile of the closed distal end  145  of the post  142  is not circular, but rather it has a very specific shape to ensure that only a refill head having a similar shaped inner cavity can receive the stem  120 , and more specifically the post  142  of the stem  120 , therein. 
     In the exemplified embodiment, the post  142  comprises a hub portion  171  extending along the stem axis B-B and at least one protuberance  172  that extends from the hub portion  171 . Specifically, the hub portion  171  has an outer surface (or a side surface)  173  and the at least one protuberance  172  extends radially from the outer surface  173  of the hub portion  171 . The outer surface  173  of the hub portion  171  is the exposed portion of the hub portion  171  that extends between the second transverse shoulder  144  and the closed distal end  145  of the post  142 . Of course, the invention is not to be so limited and it is also possible that the at least one protuberance  172  could protrude upwardly from the second transverse shoulder  144  of the stem  120  rather than protruding radially from the outer surface  173  of the hub portion  171 . Thus, in such an embodiment the at least one protuberance  172  could be spaced apart from the outer surface  173  of the hub portion  171  and thus could extend from the second transverse shoulder  144  alongside of the hub portion  171 . However, in the exemplified embodiment the at least one protuberance  172  protrudes both radially from the outer surface  173  of the hub portion  171  and upwardly from the second transverse shoulder  144 . Thus, the at least one protuberance  172  is connected directly to both the hub portion  171  and the second transverse shoulder  144 , although this is not required in all embodiments. 
     In the exemplified embodiment, the hub portion  171  has a circular cross-sectional shape. Furthermore, in the exemplified embodiment each of the protuberances  172  is a rib that protrudes radially from the outer surface  173  of the hub portion  171  and upward from the second transverse shoulder  114 . In the exemplified embodiment, each of the protuberances  172  extends linearly from the hub portion  171  to a side terminal surface  176  thereof and thus the lateral side surfaces of the protuberances  172  that extend between the hub portion  171  and the side terminal surface  176  are linear. However, in other embodiments the protuberances  172  may instead be wavy or otherwise non-linear. In the exemplified embodiment, the portions of the outer surface  173  of the hub portion  171  located between the adjacent ones of the protuberances  172  are arcuate and more specifically convex. The protuberances  172  are elongated in a direction of the stem axis B-B, meaning that the protuberances  172  have a height measured in the direction of the stem axis B-B that is greater than a width of the protuberances  172  measured in a direction transverse to the stem axis B-B from the outer surface  173  of the hub portion  171  to the side terminal surface  176  of the protuberance 
     In the exemplified embodiment, there are a plurality (i.e., three) of the protuberances  172  extending radially from the hub portion  171  in a spaced apart manner. Of course, more or less than three of the protuberances  172  may be used in other embodiments. In the exemplified embodiment, the protuberances  172  are circumferentially arranged about the hub portion  171  in a spaced apart manner relative to one another. Thus, portions of the outer surface  173  of the hub portion  171  that are located between the protuberances  172  are exposed. Although not required in all embodiments, in the exemplified embodiment the plurality of protuberances  172  are arranged in an equi-spaced manner relative to one another. Thus, in the exemplified embodiment because there are three of the protuberances  172 , they are spaced apart by approximately 120°. In the exemplified embodiment, no two protuberances  172  are located 180° apart from one another. In certain embodiments, the circumferential distance between any two of the protuberances  172  is less than 150°, more specifically less than 140°, more specifically less than 130°, and still more specifically 120° or less. Thus, there is no plane that comprises the stem axis B-B that intersects the side terminal surfaces  176  of two or the protuberances  172 . 
     As best seen in  FIG. 2 , in the exemplified embodiment at least one of the protuberances  172  faces the same direction as the actuator  113 . Thus, the actuator  113  is located on the front surface of the gripping portion  110  of the handle  100  and at least one of the protuberances  172  extends from the hub portion  171  in the direction of the front surface of the gripping portion  110 . Of course, the various protuberances  172  could be positioned at any circumferential location along the hub portion  171  in other embodiments such that each of the protuberances  172  may be located at any desired position along the hub portion  171 . 
     As noted above, in certain embodiments the closed distal end  145  of the post  142  comprises a non-circular transverse profile. In that regard, the hub portion  171  of the post  142  forms a circular central region of the post  142  and each of one or more protuberances  172  forms an arm region of the post  142  that extends radially outward from the circular central region. It is this combination of the circular central region and the one or more arms that forms the non-circular transverse profile of the post  142 . 
     In the exemplified embodiment, the hub portion  171  and each of the protuberances  172  extend the same height from the second transverse shoulder  144 , measured in the direction of the stem axis B-B. Thus, the hub portion  171  has an upper terminal surface  174  and each of the protuberances  172  has an upper terminal surface  175 . The upper terminal surfaces  174 ,  175  of the hub portion  171  and the protuberances  172  collectively define the free end of the attachment portion  140  of the stem  120 . The upper terminal surfaces  174 ,  175  of the hub portion  171  and the protuberances  172  are aligned on a plane C-C that is orthogonal to the stem axis B-B. In the exemplified embodiment, the plane C-C is perpendicular to the stem axis B-B. Thus, in the exemplified embodiment the protuberances  172  are exactly the same height as the hub portion  171  in that both extend from the distal end  143  of the base portion  141  to the free end of the attachment portion  140 . Of course, this is not required in all embodiments and the protuberances  172  could be taller or shorter than the hub portion  171  in alternative embodiments. 
     As noted above, each of the protuberances  172  extends from the hub portion  171  to the side terminal surface  176  of the protuberance  172 . The side terminal surface  176  of each of the protuberances  172  is spaced a first radial distance R 1  from the stem axis B-B. Furthermore, the outer edge  177  of the second transverse shoulder  144  is spaced a second radial distance R 2  from the stem axis B-B. In the exemplified embodiment, the second radial distance R 2  is greater than the first radial distance R 1 . Thus, none of the protuberances  172  extend all the way to the outer edge  177  of the second transverse shoulder  144 . Rather, in the exemplified embodiment a portion of the second transverse shoulder  144  extends between the side terminal surface  716  of each of the protuberances  172  and the outer edge  177  of the second transverse shoulder  144 . Of course, in alternative embodiments the protuberances  172  could extend all the way to the outer edge  177  of the second transverse shoulder  144  so that the first and second radial distances R 1 , R 2  are equal, or the protuberances  172  could extend beyond the outer edge  177  of the second transverse shoulder  144  so that first radial distance R 1  is greater than the second radial distance R 2 . 
     Referring to  FIG. 9 , as noted above the stem  120  houses the motor  160 , the eccentric  161 , and the coupling member  162  within the inner cavity  122  of the stem  120 . Furthermore, in the exemplified embodiment a shaft  190  that supports the eccentric  161  is partially embedded within an upper portion of the stem  120 . Specifically, the shaft  190  comprises a first portion  191  that is embedded within the upper portion of the stem  120  and a second portion  192  that protrudes from an upper wall  152  of the inner cavity  122  and extends into the inner cavity  122 . Specifically, the first portion  191  of the shaft  190  extends into the hub portion  171  of the post  142  and the second portion  192  of the shaft  190  extends into the inner cavity  122  of the stem  120  to support the eccentric  161 . 
     The eccentric  161  is positioned within the cavity  122  so that it is in direct contact with the second portion  192  of the shaft  190 . Thus, as the eccentric  161  rotates, vibrations are transmitted from the eccentric  161  to the shaft  190 . Having the first portion  191  of the shaft  190  extend into the hub portion  171  of the post  142  facilitates transmitting the vibrations to the head portion  220  of the refill head  200 . Portions of the stem  120 , and more specifically the post  142 , may be in surface contact with the inner surface  123  of the sleeve portion  210  of the refill head  200  to ensure acceptable transmission of the vibrations from the eccentric  161  to the head portion  220 . 
     Referring to  FIGS. 1 and 6-8  concurrently, the refill head  200  will be described in detail. The refill head  200  comprises the sleeve portion  210  and the head portion  220  that is coupled to the sleeve portion  210 . The sleeve and head portions  210 ,  220  may be integrally formed as a single unitary structure. The sleeve and head portions  210 ,  220  may comprise a base or body portion formed of a hard plastic material such as polypropylene or the like and an elastomeric material may be overmolded onto the base or body portion. In the exemplified embodiment, the refill head  200  comprises the plurality of tooth cleaning elements  215  that extend from a front surface  221  of the head portion  220  and a soft tissue cleaner  216  is located on a rear surface  222  of the head portion  220 . The soft tissue cleaner  216  comprises a pad portion  295  and a plurality of protuberances or nubs  296  protruding from the pad portion  295 . The soft tissue cleaner  216  may be formed of a resilient material such as a thermoplastic elastomer. Of course, the soft tissue cleaner  216  could be omitted in some alternative embodiments. 
     The tooth cleaning elements  215  are illustrated on the head with a specific arrangement and pattern. Specifically, the tooth cleaning elements  215  include a combination of filament bristles  217  and elastomeric cleaning elements  218  that collectively form a bristle field. The elastomeric cleaning elements  218  may be formed integrally with the soft tissue cleaner  216  when both of these elements are included, as they are in the exemplified embodiment. 
     In certain embodiments, the exact structure, pattern, orientation, and material of the tooth cleaning elements  215  are not to be limiting of the present invention. Thus, the term “tooth cleaning elements” may be used herein 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. 
     The tooth cleaning elements  215  of the present invention can be connected to the head portion  220  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 certain embodiments, the invention can be practiced with various combinations of stapled, IMT or AFT bristles. In the exemplified embodiment, the filament bristles  217  are secured to the head portion  220  using staples/anchors and the elastomeric cleaning elements  218  are integrally formed with the soft tissue cleaner  216  through one or more passageways  219  extending through the head portion  220  from the front surface  221  to the rear surface  222  thereof. 
     The sleeve portion  210  of the refill head  200  extends from a proximal end  211  to the head portion  220 . Furthermore, the sleeve portion  210  of the refill head  200  comprises an outer surface  212  and an opposite inner surface  213 , the inner surface  213  defining an internal cavity  214 . An opening  245  is formed into the proximal end  211  of the sleeve portion  210  that forms a passageway into the internal cavity  214 . The internal cavity  214  is sized and shaped to receive the attachment portion  140  of the stem  120  of the handle  100  when the refill head  200  is coupled to the handle  100 . 
     The internal cavity  214  of the sleeve portion  210  extends along a sleeve axis D-D from an open bottom end  230  (formed by the opening  245 ) at the proximal end  211  of the sleeve portion  210  to a closed top end  231  that is formed by an upper wall  229  of the sleeve portion  210 . The inner surface  213  of the sleeve portion  210  comprises a sleeve shoulder  232  that is axially spaced from the proximal end  211  of the sleeve portion  210 . The sleeve shoulder  232  faces the proximal end  211  of the sleeve portion  210 . 
     The internal cavity  214  of the sleeve portion  210  comprises a proximal section  233  adjacent to the open bottom end  230  of the internal cavity  214  and a distal section  234  that is adjacent to the closed top end  231  of the internal cavity  214 . More specifically, the proximal section  233  of the internal cavity  214  extends from the open bottom end  230  of the internal cavity  214  to the sleeve shoulder  232  and the distal section  234  of the internal cavity  214  extends from the sleeve shoulder  232  to the closed top end  231  of the internal cavity  214  (i.e., to the upper wall  229  of the sleeve portion  210 ). The proximal section  233  of the internal cavity  214  has a first axial length L 1  measured in the direction of the sleeve axis D-D and the distal section  234  of the internal cavity  214  has a second axial length L 2  measured in the direction of the sleeve axis D-D. In the exemplified embodiment, the first axial length L 1  is greater than the second axial length L 2  (a ratio of L 1 :L 2  is between 2.0:1 and 3.0:1, more specifically 2.2:1 and 2.8:1, and still more specifically 2.4:1 and 2.5:1, although the invention should not be so limited in all embodiments). Furthermore, in the exemplified embodiment the proximal section  233  of the internal cavity  214  tapers with distance from the proximal end  211  of the sleeve portion  210  towards the sleeve shoulder  232 . Nonetheless, due to the sleeve shoulder  232  being the dividing line between the proximal and distal sections  233 ,  234  of the internal cavity  214 , the proximal section  233  has a minimum diameter (or width measured transverse to the sleeve axis D-D) that is greater than a maximum diameter (or width measured transverse to the sleeve axis D-D) of the distal section  234 . 
     Referring specifically to  FIGS. 7 and 8 , the distal section  234  of the internal cavity  214  will be further described.  FIG. 8  illustrates a cross-section taken through the distal section  234  of the internal cavity  214  and it reveals that the distal section  234  of the internal cavity  214  comprises a central portion  235  located on the sleeve axis D-D and at least one slot portion  236  radially extending from the central portion  235 . In the exemplified embodiment, there are three of the slot portions  236 , although more or less than three slot portions  236  may be included in other embodiments. The slot portions  236  are circumferentially arranged about the central portion  235  in a spaced-apart manner from one another. In the exemplified embodiment the number of slot portions  236  matches the number of protuberances  172  of the post  142  of the attachment portion  140  of the stem  120 , as described more fully below with reference to  FIG. 10 . Each of the slot portions  236  has an open lower end formed into the sleeve shoulder  232  and terminates at an upper surface. Furthermore, in the exemplified embodiment each of the slot portions  236  of the distal section  234  of the internal cavity  214  comprises a substantially constant transvers cross-sectional area. 
     The central portion  235  of the distal section  234  of the internal cavity  214  is defined by a plurality of arcuate sidewalls  237 . Adjacent ones of the arcuate sidewalls  237  are separated by one of the plurality of slot portions  236 . Furthermore, each of the slot portions  236  is defined by first and second sidewalls  238 ,  239  that extend radially outward from the central portion  235  and terminate in an end wall surface  240 . Thus, each of the first and second sidewalls  238 ,  239  extend from one of the arcuate sidewalls  237  to the end wall surface  240 . In the exemplified embodiment, the central portion  235  is circular and the slot portions  236  are rectangular, although the invention need not be limited to these specific shapes in all embodiments. As seen in  FIG. 8 , in the exemplified embodiment one of the slot portions  236  extends radially in a first direction from the sleeve axis D-D, and at least one of the tooth cleaning elements  215  extends from the head portion  220  in the first direction. Thus, one of the slot portions  236  extends in the same direction as one or more of the tooth cleaning elements  215 . 
     Referring to  FIGS. 9 and 10 , cross-sections of the assembled oral care implement  1000  are illustrated whereby the refill head  200  is coupled to the stem  120  of the handle  100 . As can be seen, the attachment portion  140  of the stem  120  is located within the internal cavity  214  of the refill head  200  such that the post  142  is located within the distal section  234  of the internal cavity  214 . More specifically, the hub portion  171  of the post  142  is located within the central portion  235  of the distal section  234  of the internal cavity  214  and the protuberances  172  of the post  142  are located within the slot portions  236  of the distal section  234  of the internal cavity  214 . In this particular embodiment, the exposed portions of the outer surface  173  of the hub portion  171  are in contact with the arcuate sidewall surfaces  237  defining the central portion  235  of the distal section  234  of the internal cavity  214  and the side terminal surfaces  176  of the protuberances  172  are in contact with the end wall surfaces  240  of the slot portions  236  of the distal section  234  of the internal cavity  214 . 
     Thus, in this embodiment there is a reasonably snug fit between the post  142  and the distal section  234  of the internal cavity  214 . This ensures that vibrations generated by the vibration generating device  199  are transmitted to the refill head  200  so that they can benefit a user during toothbrushing. Of course, minor gaps may be present for tolerance to ensure that the post  142  of the stem  120  can fit within the distal section  234  of the internal cavity  214 . However, such gaps when included should be quite small to ensure that vibrations are transmitted to the head portion  220  of the refill head  200  as described herein. 
       FIG. 11  illustrates a cross-sectional view similar to  FIG. 10  except in accordance with an alternative embodiment. Specifically, in this embodiment the post  142  has the exact same structure as previously described in that it comprises a hub portion  171  and a plurality of protuberances  172  protruding from the outer surface  173  of the hub portion  172 . What is difference in this embodiment is the shape/configuration of the distal section  234  of the internal cavity  214  of the sleeve portion  210  of the refill head  200 . Specifically, the distal section  234  of the internal cavity  214  in this embodiment does not include a central portion and slot portions extending radially therefrom. Rather, the distal section  234  of the internal cavity  214  is defined by an inner surface  251  which in the exemplified embodiment is a continuous, annular surface in the shape of a circle. Thus, there are no sidewalls and end wall surfaces, but rather a singular inner surface  251  defines the entirety of the distal section  234  of the internal cavity  214 . 
     Thus, when fully assembled, the outer surface  173  of the hub portion  171  of the post  142  is spaced apart from the inner surface  251  of the distal section  234  of the internal cavity  214  of the sleeve portion  210  of the refill head  200  while the side terminal surfaces  176  of the protuberance  172  of the post  142  are in surface contact with the inner surface  251  of the distal section  234  of the internal cavity  214  of the sleeve portion  210  of the refill head  200 . Thus, there are several air gaps  152  that remain that are bounded by adjacent protuberances  172 , a portion of the inner surface  251  of the internal cavity  214 , and a portion of the outer surface  173  of the hub portion  171 . Because there are three protuberances  172  in the exemplified embodiment, there are also three air gaps  152 , although more or less air gaps will be included based on the number of protuberances  172 . 
     Thus, in this embodiment there is conformal surface contact between the side terminal surfaces  176  of the protuberances  172  and the inner surface  251  of the internal cavity  214 , but there is no surface contact between the outer surface  173  of the hub portion  171  and the inner surface  251  of the internal cavity  214 . Vibrations generated by the vibration generating device  199  may still be transmitted through the post  142  to the refill head  200  via the contact between the protuberances  172  and the inner surface  251  of the internal cavity  214 . 
     While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims.